UPERFUND '86 SUPERFUND '86 SUPERFUND '86 SUPERFUND '86 SUPERFUND '86 SUPERFUND '86
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THE 7TH NATIONAL CONFERENCE ON
MANAGEMENT OF
UNCONTROLLED HAZARDOUS
WASTE SITES
DECEMBER 1-3, 1986 • WASHINGTON, DC
AFFILIATES
Hazardous Materials Control Research Institute
U.S. Environmental Protection Agency
U.S. Army Corps of Engineers
U.S. Geological Survey
Agency for Toxic Substances & Disease Registry
American Society of Civil Engineers
Association of Engineering Geologists
Department of Defense
National Environmental Health Association
National Lime Association
National Solid Waste Management Association
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PREFACE
1986 has been a trying year for all of us involved in Superfund activities. At last, however, the
waiting is over. Superfund extension was signed into law in October. The extension of CERCLA to 1990
is at a much increased funding level over the previous five-year period of 1980-1985. Much of the in-
crease in these resources will be devoted to expansion of remedial construction projects at NPL sites.
During FY 1985, the U.S. EPA began construction work at about 50 sites, compared with 15 sites dur-
ing FY 1984. Superfund extension requires more than 300 remedial starts in this next five year period.
Under CERCLA, the U.S. EPA has three major elements of its strategy. First, uncontrolled hazar-
dous waste sites in the Agency's current inventory will be assessed. Second, those sites which present an
imminent threat to public health or the environment will be stabilized. Third, those sites that should
receive priority attention for remedial cleanup action will be dealt with first, using the National Contin-
gency Plan for guidance.
CERCLA will place the states in the implementing role and will delegate responsibilities to the U.S.
EPA Regional Administrators. In the implementation of the CERCLA programs, new sites will be iden-
tified and new technologies will be developed and employed.
These Proceedings emphasize actual experience obtained during the various stages necessary for
remediation of the numerous Superfund sites. These Proceedings therefore enable immediate and effective
technology transfer for response to other NPL Superfund sites.
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ACKNOWLEDGEMENT
HMCRI would like to express our appreciation to all the individuals and organizations who assisted
in the development of the program, the Proceedings and the success of the 7th National Conference and
Exhibition on Management of Uncontrolled Hazardous Waste Sites—SUPERFUND '86.
Affiliated organizations include:
Hazardous Materials Control Research Institute
U.S. Environmental Protection Agency
U.S. Army Corps of Engineers
U.S. Geological Survey
Agency for Toxic Substances & Disease Registry
American Society of Civil Engineers
Association of Engineering Geologists
Department of Defense
National Environmental Health Association
National Lime Association
National Solid Waste Management Association
The professionals on the Program Review Committee reviewed hundreds of abstracts to develop this in-
formative and interesting program. The Committee was composed of:
Hal Bernard, Hazardous Materials Control Research Institute
Michael Black, U.S. Environmental Protection Agency/Hazardous Waste Engineering
Research Laboratory
John Brugger, U.S. Environmental Protection Agency/Hazardous Waste Engineering
Research Laboratory
Steve Church, National Environmental Health Association
Ken Gutschick, National Lime Association
Paul Lancer, U.S. Army Corps of Engineers
Walt Leis, Association of Engineering Geologists
Denny Naugle, Department of Defense
Suellen Pirages, National Solid Waste Management Association
Bob Quinn, U.S. Environmental Protection Agency
Jerry Steinberg, Hazardous Materials Control Research Institute/Water and Air Research
Andres Talts, American Society of Civil Engineers/Defense Environmental Leadership Project
Bob Williams, Agency for Toxic Substances and Disease Registry
A very special thanks to Dr. Gary Bennett, Professor of Biochemical Engineering, The University of
Toldeo; Judy Bennett, Editorial Consultant, Toledo; and Hal Bernard, Hazardous Materials Control
Research Institute, for editing this massive undertaking in the short turnaround time. A special thanks also
to the typesetters, graphics and proofreading team for meeting impossible deadlines and to the HMCRI
staff for keeping it going in the right direction.
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CONTENTS
.11
.14
.18
IMPLEMENTATION OF SUPERFUND
Comprehensive Environmental Assessment and
Response Program Confirmation and
Evaluation Activities
M.K. Martz, D.Env.; K.H. Rea, Ph.D.; R. W.
Vocke, Ph.D. & R. W. Ferenbaugh, Ph.D.
Safety Improvement Using Simulation and
Advanced Control in Hazardous Waste Incineration
S.K. Shoor & R.J. Clinton
Deleting Sites from the National Priorities List
Amelia Z. Heffernan, Kathleen A. Hutson &
Steven C. Golian
Implementation of Superfund: Community
Right-to-Know
Jim Makris
Improvements in Superfund Site Management
Christopher Sebastian, John Mateo, Randall
Kaltreider & Martha Monserrate
LEGAL/ENFORCEMENT
Maximizing Cleanup Options and Minimizing
Liabilities Under CERCLA
Theodore Hadzi-Antich
U.S. EPA/State Relationship in CERCLA
Enforcement Actions at National Priorities
List Sites
Anthony M. Diecidue & Diana Baumwoll
The Effect of the National Contingency Plan
Revisions on Federal, State and Private
Superfund Cleanup Actions
John C. Hall
The Community Relations Benefits of Resolving
Private Property Legal Issues
Raymond C. Givens & Ian von Lindern, Ph.D.
U.S. EPA SUPPORT CONTRACTS
Remedial Planning Contracts 35
Nancy M. Willis
The Field Investigation Team Contracts-
Scope and Functions 36
Scott Fredericks
Technical Enforcement Support Contracts 38
Nancy Deck
Contracting in the Superfund Removal Program 40
James Jowett & Linda Garcynski
.22
.27
.31
Improving and Implementing Superfund
Contracting Strategies 46
Stanley P. Kovell
INDEMNIFICATION & COSTS
Addressing the Consultant's Liability Concerns 47
Laurence T. Schaper, P.E. & Dennis R. Schapker, P.E.
Federal Indemnification of Superfund Program
Response Action Contractors 52
Robert Mason, Mark F. Johnson & Edward
Yang, Ph.D.
A Model for Apportioning the Cost of Closure
of a Waste Site 56
Robert T. Denbo, Sr. & Dhamo S. Dhamotharan
Considerations of Discounting Techniques
Applied to Superfund Site Remediation 61
Thomas J. Buechler, P.E. & Keith A. Boyd, P.E.
HEALTH ASSESSMENT
.65
.69
.74
.78
The Application of Quantitative Risk
Assessment to Assist in Evaluating Remedial
Action Alternatives
Lawrence J. Partridge, Sc.D.
Risk and Exposure Assessment of an
Abandoned Hazardous Waste Site
James D. Werner
Death or Cancer—Is There Anything Else?
B. Kim Mortensen, Ph.D.
Missouri Dioxin Studies: Some Thoughts
on Their Implications
John S. Andrews, Jr., M.D.; Paul A. Stehr-
Green, Dr. P.M.; Richard E. Hoffman, M.D.;
Larry L. Needham, Ph.D.; Donald G.
Patterson, Jr., Ph.D.; John R. Bagby, Jr., Ph.D.;
Daryl W. Roberts; Karen B. Webb, M.D. &
R. Gregory Evans, Ph.D.
SITE DISCOVERY & ASSESSMENT
A National Study of Site Discovery Methods 84
Margie Ortiz, Francis J. Priznar & Paul Beam
The Difficulties of Modeling Contaminant
Transport at Abandoned Landfill Sites 88
Mark D. Taylor, P.E.
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Town Gas Plants—History, Problems and
Approaches to Study
G.J. Anastos, Ph.D., P.E.; C.M. Johnson, P.E.;
R.M. Shapot & V.G. Velez
Dioxin Contamination at Historical Phenoxy
Herbicide Mixing and Loading Locations
Steven H. Simanonok & Pamela Beekley
SCREENING TECHNIQUES & ANALYSIS
Field Screening Techniques Developed
Under the Superfund Program
J.N. Motwani, P.E.; Stacie A. Popp; Glenn M.
Johnson, P. E. & Rae A. Mindock
Statistical Modeling of Geophysical Data
Charles T. Kufs, P.O.; Donald J. Messinger &
Stephany Del Re
Portable X-Ray Fluorescence as a Screening
Tool for Analysis of Heavy Metals in
Soils and Mine Wastes
Richard W. Chappell. Andrew O. Davis, Ph.D.
& Roger L. Olsen, Ph.D.
Field Methods and Mobile Laboratory Scenarios
for Screening and Analysis at Hazardous
Waste Sites
G. Hunt Chapman, Paul Clay. C. Keith Bradley
& Scott Fredericks
SAMPLING & MONITORING
Exploratory Drilling into a Buried Uncontrolled
Drum Disposal Pit
Patrick F O 'Hara, Kenneth J. Bird <$
William A. Baughman
Statistical Approach to Groundwater
Contamination Mapping with Electromagnetic
Induction: Data Acquisition and Analysis
Dennis D. Weber, Ph.D. & George T. Flat man
Processes Affecting the Interpretation of
Trichloroethylene Data from Soil Gas Analysis
Elsa y. Krauss, John G. Osier & Kurt O.
Thomsen, Ph.D.. P.G.
Field Qualit) Assurance: A System for Plan
Review, Tracking and Activit> Audit
Kathleen G. Shimmin, Harry E. Demarest
& Peter L. Rubenstein
The Importance of Field Data Acquisition in
Hydrogeologic Investigations at Hazardous
Waste Sites
Richard J. DeLuca
A Practical Methodology for Designing and
Conducting Ambient Air Monitoring at
Hazardous Waste Facilities
Mark J. Asoian, Michael J. Barboza, P.E.
& Louis M. Militana
Low Level Groundwater Contamination
Investigation at the Cleve Reber Superfund Site
Kenneth R. Miller, P.E., Jeffrey P Hullinger,
P.E. & Stephen A. Gilrein
A Cost-Saving Statistically Based Screening
Technique for Focused Sampling of a Lead-
Contaminated Site
Anthony F. Moscati, Jr., D.Env.; Eric M.
Hediger & M. Jay Rupp
RISK ASSESSMENT/DECISION ANALYSIS
.93
.97
.105
.110
.115
.120
.126
.132
.138
.143
.148
.152
.158
.164
U.S. EPA Guidelines for Risk Assessment
Peter W. Preuss, Ph.D.; Alan M. Ehrlich, Ph.D.
& Kevin G. Garrahan, P.E.
A Comparative Evaluation of Methods for
Determining Alternative Concentration Limits
Gay nor W. Dawson & C. Joseph English
Risk Assessment for Underground Storage Tank*
Captain Dennis J. Foth, P. E.
The U.S. EPA's Methodology for Adjusting
the Reportable Quantities of Potential Carcinogens
Vincent James Cogliano, Ph.D.
Quantitative Risk Assessment as the Basis for
Definition of Kxtent of Remedial Action at the
Leetown Pesticide Superfund Site
Amy E. Hubbard, Robert J. Hubbard, John A.
George & William A. Hagel
Innovative Use of Toxicological Data to Improve
C'osl-Kffcctiveness of Waste Cleanup
Todd W. Thorslund, Ph.D.; Gail Charnley,
Ph.D. & Elizabeth L. Anderson, Ph.D.
The Use of Geographic Information Systems as
an Interdisciplinary' Tool in Smelter Site
Remediations
Ian H. von Lindern, P.E.. Ph.D. & Margrit C.
von Braun, P.E.
Improving the Implementation of Remedial
Investigation/Feasibility Studies Using
Computerized Expert Systems
J. Steven Paquette, Donald A. Bissex, Royce
Buehler & Lisa Woodson
Coping with Data Problems While Performing
Risk Assessments at Superfund Sites
David H. Homer, Ph.D.; John A. Dirgo; Harry
V. Ellis III, Ph.D. & Eric S. Monan
CONTAMINATED AQUIFER CONTROLS
Educational Needs for Hazardous Waste
Site Investigations: Technology Transfer in
Geoph\sics and Geostalistics
George T. Flat man, Evan J. England, Ph.D.
& Denni^ D. Weber. Ph.D.
A Collection/Treatment/Recharge/ Flushing
Groundwater Remediation Program
Kurt O. Thomsen, Ph.D., P.G.; Bakulesh H.
Khara, P.E. & Aloysius 1 Aguwa, Ph.D.
Establishing and Meeting Groundwater
Protection Goals in the Superfund Program
Edwin F. Barth III, Bill Hanson & Elizabeth
A. Shaw
Pitfalls of Geophysics in Characterizing
Underground Hazardous Waste
William J. Johnson & Donald H Johnson
Qualif) Assurance Testing of Monitoring
Well Integrity
Janet la N. Kno.\ & Peter R. Jacobson
.167
.173
.176
.182
.186
.193
.200
.208
.213
.217
.220
.224
.227
.233
LKACHATE FATE & CONTROL
Leachale Characterization and Synthetic
Leachate Formulation for Liner Testing
Jennifer A. Bramlett, Edward W. Repa, Ph.D.
& Charles I. Mashni
.237
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Environmental Behavior of Polynuclear
Aromatic Hydrocarbons at Hazardous Waste Sites
Paul C. Chrostowski, Ph.D. & Lorraine J. Pearsall
Creep Characteristics of Drainage Nets
Robert C. Slocumb, Darwin D. Demeny &
Barry R. Christopher
Innovative Engineered Systems for Biological
Treatment of Contaminated Groundwater
Paul M. Sutton, Ph.D.
Horizontal Drilling Beneath Superfund Sites
Wade Dickinson, R. Wayne Dickinson, Thomas
W. Crosby & Harlan N. Head, Ph.D.
BARRIER TECHNOLOGY
Performance Evaluation of Cement-Bentonite
Slurry Wall Mix Design
Christopher R. Ryan & Steven R. Day
Geomembrane Uses with Hazardous Wastes
John D. VanderVoort
Nondestructive Testing Techniques to Assess
Geomembrane Seam Quality ,
Arthur E. Lord, Ph.D.; Robert M. Koerner,
Ph.D., P.E. & Robert B. Crawford
Attenuating Contaminant Migration with
Neutralizing and Sorptive Admix Barriers
B.E. Opitz, D.R. Sherwood & W.J. Martin
Geomembrane Barrier Technology for
Superfund Cleanup
Mark W. Cadwallader
WASTE STABILIZATION/FIXATION
A Construction Quality Control Program for
Sludge Stabilization/Solidification Operations
Gary J. Deigan & Larry G. Copeland, P.E.
Considerations in Data Collection for Evaluation
of Source Control Alternatives at Hazardous
Waste Landfills
James A. Hill & Robert J. Montgomery, P.E.
Fixation/Solidification of Hazardous Waste at
Chemical Waste Management's Vickery, Ohio
Facility
Michael F.R. Curry
.242
.247
.253
.258
.264
.269
.272
.277
,282
.287
.292
.297
TREATMENT & DISPOSAL
Field Experiences with Silicate-Based Systems
for the Treatment of Hazardous Wastes
G.J. Trezek, J. Wotherspoon, D.J. Leu, L.R.
Davis & C.D. Folk
Lime Treatment of Liquid Waste Containing
Heavy Metals, Radionuclides and Organics
Andre DuPont
Demonstration of Land Treatment of
Hazardous Waste
Roger L. Olsen, Ph.D.; Patricia R. Fuller;
Eric J. Hinzel & Peter Smith
The B.E.S.T. Sludge Treatment Process: An
Innovative Alternative Used at a Superfund Site ...
Jose A. Burruel, P.E.; Shane Hitchcock; Mike
Norman & Mary Jane Lampkins
.303
.306
.313
.318
IN SITU TREATMENT
In Situ Air Stripping: A New Technique for
Removing Volatile Organic Contaminants from Soils..
George Anastos, Ph.D., P.E.; Michael H.
Corbin, P.E. & Michael F. Coia
In Situ Vitrification—A Candidate Process for
In Situ Destruction of Hazardous Waste
V.F. FitzPatrick
Aquifer Restoration via Accelerated In Situ
Biodegradation of Organic Contaminants
Paul M. Yaniga & William Smith
Operation of a Light Hydrocarbon Recovery
System: Theory, Practical Approach and
Case History
Robert M. Galbraith & John W. Schweizer, P.E.
ALTERNATIVE TECHNOLOGIES
.322
.325
.333
.339
Mobile Treatment Technologies
William K. Glynn & Edward P. Kunce
Response to an Underground Fire at an
Abandoned Hazardous Waste Landfill
David G. Pyles, Scott D. Springer & Briand
C. Wu, Ph.D.
Superfund Innovative Technology Evaluation
Program
Ronald D. Hill, Donald C. White, P.E. &
Robert N. Ogg, P.E.
Applying Alternative Technologies at
Superfund Sites
Donald C. White, P.E.; Jeffrey R. Dunckel
& Timothy D. Van Epp
Field Verification of the HELP Model for
Multilayer Hazardous Waste Landfill Covers
Nathaniel Peters, II; Richard C. Warner &
Anna L. Coates
SITE REMEDIATION TECHNIQUES
Application of Fluorescence and FT-IR
Techniques to Screening and Classifying
Hazardous Waste Samples
DeLyle Eastwood, Ph.D. & Russell Lidberg
Toxic Gas Collection and Treatment System at
an Uncontrolled Superfund Site
Wm. Edward McCracken, Ph.D., P.E. &
David R. Henderson
Rapid, Cost-Effective GC Screening for
Chlorinated Pesticides and Volatile Organics
at CERCLA Sites
Richard A. Cheatham, Jeffrey Benson, Jeralyn
Guthrie, William Berning & Roger L. Olsen, Ph.D.
The U.S. EPA's Expedited Response Action
Program
Robert D. Quinn; William M. Kaschak, P.E.;
J. Steven Paquette & Wendy L. Sydow
Data Quality Objectives Development for
Remedial Investigation/Feasibility Studies
Linda Y. Boornazian, Randall Kaltreider,
Tom A. Pedersen & Wendy L. Sydow
An Approach to Remediating Contaminated
Bedrock Aquifers
Peter J. McGlew
.345
.350
.356
.361
.365
.370
.380
.386
.393
.398
.403
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Impact of the New Superfund on the Remedial
Action Program 407
Gregory A. Vanderlaan & D. Brint Bixler
Superfund Revisited 412
Graver H. Emrich, Ph.D.
CASE HISTORIES
Investigation and Remediation of a Pond
Contaminated by Diesel Fuel 415
Lon M. Cooper, P.E. & Richard K. Hosfeld, C.P.C.
Innovative and Cost-Saving Approaches to
Remedial Investigation and Cleanup of a
Complex PCB-Contaminated Site 420
Keven Chisholm, P.E.; Charles E. Newton,
Ph.D. & Anthony F. Moscali, Jr., D.Env.
Installation of Monitoring Wells into Wastes
in the Love Canal 424
Jeffrey S. Pickett & William R. Fisher
Groundwater Studies, Case Histories and
Applied Modeling 430
Michael O. Smith
The NIKE Missile Site Investigation Program 436
Steven L. Shugart, P.O.; Louis S. Karably,
P.E., P.O. & Harold T. Whitney, Ph.D., P.E.
Remedial Investigations and Emergency
Response Measures at a Montana RCRA/
CERCLA Site 441
Lena Blais, P.E.
A Third Part> Neulral •'Validates" an RI/FS 445
Lisa P. Carson & Bruce Clemens, P.E.
Remedial Investigation/Feasibility Study,
NOVACO Industries, Michigan 448
Mary Elaine Gustafson & Stephen J. Hahn
Rational Approaches to Selecting, Performing
and Interpreting Medical Tests In a Medical
Surveillance Program
Bertram W. Carnow, M.D. & Shirley A.
Conibear, M.D.
Superfund Risk Assessment: The Process and Its
Application to Uncontrolled Hazardous Waste Sites
Craig Zamuda, Ph.D.; Jim Lounsbury &
David Cooper
Proper Design and Installation Techniques for
Groundwater Monitoring Wells
David M. Nielsen. C.P.C.
Interrelationship Between Superfund and RCRA ...
Bill Hanson & Steven Smith
Risk/Decision Analysis Module (RIDAM)
In Expert Systems
Chia Shun Shih & Hal Bernard
Geophysical Techniques for Sensing Buried
Wastes and Waste Migration: An Update
Richard C. Benson, C.P.C. & Lynn B. Yuhr
The Role of the Agency for Toxic Substances and
Disease Registry In Superfund Response
Robert C. Williams. P.E.; William Cibulas, Jr.,
Ph.D.; C. Harold Emmett. P.E. & Jeffrey A.
Lybarger, M.D.
Toward an Effective Strategy for Dealing
with Superfund
Peter H. Holler
Selecting PPE — "I Haven't a Thing to Wear"
Richard M. Ronk
Health, Safety and Training Requirements for
Hazardous Waste Site W orkers
Martin S. Mathamel
.455
.457
.460
.462
.463
.465
.467
.469
.471
.472
SEMINARS
The Soil Chemistry of Hazardous Materials:
Basic Concepts and Principles
James Dragun, Ph.D.
.453
Exhibitors 475
Author Index 485
Subject Index 490
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Comprehensive Environmental Assessment
And Response Program Confirmation
And Evaluation Activities
M.K. Martz, D.Env.
K.H. Rea, Ph.D.
R.W. Vocke, Ph.D.
R.W. Ferenbaugh, Ph.D.
Los Alamos National Laboratory
Los Alamos, New Mexico
ABSTRACT
The U.S. Department of Energy Albuquerque Operations
Office (U.S. DOE-AL) initiated the Comprehensive Environ-
mental Assessment and Response Program (CEARP) to iden-
tify, evaluate and conduct remedial actions at hazardous waste
disposal and contamination sites on the eight nuclear weapons
development and production installations under its jurisdiction.
The CEARP is being implemented in five phases: Phase 1—In-
stallation Assessment; Phase 2—Confirmation; Phase 3—Tech-
nological Assessment; Phase 4—Remedial Action; and Phase 5—
Compliance and Verification.
During Phase 1, regulatory compliance was evaluated and
disposal/contamination sites were identified. Phase 2 will provide
the field data for site characterization, risk assessment, deter-
mination of need for corrective action and evaluation of possi-
ble remedial actions at hazardous waste sites. Phase 2 is being
conducted in two stages: (1) monitoring plan development/recon-
naissance sampling and (2) site characterization/remedial inves-
tigation. Problem sites across the U.S. DOE-AL complex were
prioritized for site characterization and CEARP Phase 2 activ-
ities have been initiated.
INTRODUCTION
To fulfill its obligations under CERCLA and RCRA, the U.S.
Department of Energy Albuquerque Operations Office (U.S.
DOE-AL) initiated a program to identify, evaluate and conduct
remedial actions at hazardous waste disposal and contamina-
tion sites under its jurisdiction. The Comprehensive Environ-
mental Assessment and Response Program (CEARP) is the U.S.
DOE-AL implementation of the CERCLA program outlined for
federal facilities by the U.S. EPA. The CEARP is being imple-
mented in five phases: Phase 1—Installation Assessment [regu-
latory compliance evaluation and site identification, inspection,
preliminary assessment and Hazard Ranking System (HRS)
evaluation]; Phase 2—Confirmation (site characterization/re-
medial investigations); Phase 3—Technological Assessment (feas-
ibility studies and remedial action selection); Phase 4—Remed-
ial Action (remedial action design and implementation); and
Phase 5—Compliance and Verification (site closeout and moni-
toring).
The CEARP addresses the eight nuclear weapons installations
under DOE-AL. They include three research and development
laboratories [Los Alamos National Laboratory (Los Alamos,
New Mexico), Sandia National Laboratories-Albuquerque (Al-
buquerque, New Mexico) and Sandia National Laboratories-
Livermore (Livermore, California)] and five production plants
[the Kansas City Plant (Kansas City, Missouri), Mound (Miamis-
burg, Ohio), the Pantex Plant (Amarillo, Texas), the Pinellas
Plant (St. Petersburg, Florida) and the Rocky Flats Plant (Gold-
en, Colorado)]. Implementation of the CEARP at the eight in-
stallations is being accomplished through the combined efforts
of DOE-AL, Los Alamos National Laboratory, DOE Area
Offices, the prime contractor at each facility and subcontrac-
tors as appropriate.
PHASE 1 FINDINGS
The CEARP Phase 1 Installation Assessment activities are
Hearing completion. The purpose of Phase 1—Installation Assess-
ment was twofold: (1) to evaluate current operations for com-
pliance with environmental regulations and (2) to identify/eval-
uate past and present potential hazardous waste disposal sites
and contamination areas that may require remedial action under
RCRA continuing release provisions or under CERCLA. During
the CEARP Phase 1 evaluation, regulatory compliance issues
were addressed and referred to U.S. DOE-AL and the installa-
tion contractor for resolution. Potential CERCLA/RCRA sites
were identified and assigned a positive, negative or uncertain
finding, as appropriate, for the following U.S. EPA CERCLA
program elements: Federal Facility Site Discovery and Identifica-
tion Findings (FFSDIF), Preliminary Assessment (PA) and Pre-
liminary Site Inspection (PSI). No CERCLA findings were re-
corded for sites where past cleanup activities had been docu-
mented or current cleanup operations were in progress. Sites
where remedial action had already been initiated were categor-
ized as CEARP Phase 4, and sites where past remedial action was
well documented will be verified under CEARP Phase 5.
Sites with negative findings (i.e., sites where no significant
quantities of hazardous substances remain because of decay/de-
composition/chemical reaction or suspected sites where nothing
could be found) were documented and eliminated from further
evaluation. Sites were assigned an uncertain finding when the
status of hazardous substances in the environment could not be
determined from the records and insufficient information was
available to conduct a Hazard Ranking Study (HRS) evalua-
tion. Sites with uncertain findings will be evaluated further
through reconnaissance sampling and followup during the sup-
plementary stages of CEARP Phase 1. Based on the additional
data, these sites will be scored using the U.S. EPA HRS and a
IMPLEMENTATION OF SUPERFUND
1
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risk assessment conducted to determine whether the sites should
be targeted for CEARP Phase 2 site characterization and poten-
tial remedial action (CEARP Phases 3 and 4).
Sites with positive findings under CEARP Phase 1 were scored
using the U.S. EPA HRS when sufficient information was avail-
able. Sites that received U.S. EPA HRS scores greater than the
28.5 threshold used by the U.S. EPA for inclusion on the Na-
tional Priorities List (NPL) are identified as CERCLA sites.
These sites are being carried forward into CEARP Phase 2 for
confirmation (site characterization/remedial investigation) and
are being evaluated in accordance with the U.S. EPA CERCLA
guidance for Federal facilities. Sites which did not receive U.S.
EPA HRS scores greater than 28.5 but which may exceed U.S.
DOE clean-up criteria, potentially present an environmental risk
or pose regulatory compliance concerns also are being carried
forward for site characterization and risk assessment under
CEARP Phase 2. Sites with positive findings under CEARP
Phase 1, but without sufficient information to be scored using
the U.S. EPA HRS, are being further studied in the supple-
mental portion of CEARP Phase 1 to obtain the additional in-
formation needed for scoring.
During the CEARP Phase 1 activities conducted to date, more
than 500 potential sites have been screened at the eight facilities.
These sites range from employees' recollections of minor spills of
oil or hazardous materials to documented waste disposal sites
containing hazardous chemical and/or radioactive wastes. All
reported sites were listed and investigated. Many of the sites iden-
tified do not contain significant amounts of hazardous materi-
als. However, all the sites with positive or uncertain findings, as
indicated above, have been targeted for further evaluation. Ap-
proximately 130 sites have been or will be carried forward into
CEARP Phase 2 for site characterization/remedial investiga-
tion. Another 200 of these sites are being further evaluated under
the supplementary CEARP Phase 1 reconnaissance and followup
program to document the present conditions and determine if
site characterization is appropriate.
Scoring of the potential CERCLA/RCRA sites using the U.S.
EPA HRS indicated that only one of the U.S. DOE-AL installa-
tions, the Rocky Flats Plant, has any sites that exceed the U.S.
EPA threshold for listing on the NPL. The sites with high scores
at the Rocky Flats Plant have received priority consideration and
are being evaluated in accordance with U.S. EPA CERCLA re-
quirements.
Although a variety of sites were scored at the other seven in-
stallations, the scores received were significantly lower than the
28.5 NPL threshold. Preliminary evaluation of the sites with low
scores has indicated that the U.S. EPA HRS is not adequate to
determine the long-term potential for migration of contaminants
from these sites and, hence, the need for remedial action. In
addition, the scores cannot be used to rank relative priorities be-
cause the U.S. EPA HRS does not readily account for the differ-
ences in transport potential from the diverse environments en-
countered in the CEARP investigations. Therefore, the U.S.
EPA HRS scores have been used in the CEARP only to indicate
a relative comparison between CEARP sites and other U.S. EPA
high priority NPL sites.
Table 1 lists the U.S. DOE-AL installations and provides a
brief summary of the principal functions, some of the special
hazardous materials routinely handled and materials which po-
tentially may be found in the environment. Because of the unique
testing conducted at both Sandia National Laboratories-Albu-
querque and Los Alamos National Laboratory since the early
days of nuclear weapons development, these installations contain
a significant number of potentially contaminated firing sites (sites
for test firing high-explosive configurations containing various
heavy metals) in addition to waste disposal sites. The CEARP
Phase 1 evaluation identified many of these sites for further site
characterization. Migration potential and risk evaluations from
these sites will be included as an important part of the successive
CEARP activities.
PHASE 2 PURPOSE AND SCOPE
The CEARP Phase 2 Confirmation activities provide the field
data for site characterization, risk assessment, determination of
the need for corrective action and evaluation of possible remed-
ial actions at hazardous waste sites. To accomplish this, the sites
are characterized in sufficient detail to: (1) determine the area!
and vertical extent of contamination, (2) make a qualitative and
quantitative determination of the spatial distribution of contam-
inants within the site, (3) evaluate the potential for migration
of contaminants from the site and (4) assess the risks to humans
and the environment.
CEARP Phase 2 is being conducted in two steps: Phase 2A—
Monitoring Plan development (i.e., reconnaissance sampling and
development of plans for remedial investigations) and Phase
2B—Site Characterization (remedial investigations). Because the
data collected during the CEARP Phase 2 site characterization
activities will provide the necessary information for conducting
the Phase 3 technology assessment (feasibility study), the CEARP
Phase 2 site characterizations are being conducted in tandem
with the CEARP Phase 3 technological assessments/feasibility
studies.
PHASE 2 IMPLEMENTATION
Phase 2A—Monitoring Plans
Development of CEARP Phase 2A reconnaissance sampling
and monitoring plans was initiated for the U.S. DOE-AL facil-
ities during 1986. A three-tiered approach is being used in the
development of the monitoring plans: (1) the CEARP Generic
Monitoring Plan (CGMP), (2) Installation Generic Monitoring
Plans (IGMP) and (3) Site-Specific Monitoring Plans (SSMP).
The CGMP provides the generic policies and procedures that
are being implemented at all the installations and at all the sites.
An IGMP is being prepared for each U.S. DOE-AL installa-
tion. Each IGMP identifies sites targeted for remedial investiga-
tion at this time and provides installation-specific information
that is being or will be incorporated into each of the SSMPs.
An SSMP will be prepared for each planned remedial investiga-
tion. Individual remedial investigations are being conducted for
individual sites or groupings of sites (combined because of prox-
imity or similarities). Each tier of plans consists of a synopsis
(introduction), sampling plan, health and safety plan, technical
data management plan and quality assurance/quality control
plan.
At the SSMP level, the synopsis describes the known charac-
teristics of the site, identifies possible remedial actions and speci-
fies the data needed to evaluate the migration potential and en-
vironmental risks; finally it allows one to select one of the altern-
ative remedial actions. The SSMP sampling plan is used to guide
the site characterization process to: (1) define the objectives of
the investigation; (2) select a sampling approach; (3) identify
sampling locations and the number and types of samples; (4)
specify sample collection and analytical methods; and (5) define
sampling logistics. The SSMP health and safety plans identify
hazards and evaluate personnel risks, stipulate personnel protec-
tion requirements and provide contingency plans for dealing
with specified emergencies. The SSMP technical data manage-
ment plans provide procedures for storing, manipulating, retriev-
ing and archiving data collected during the site characterization
IMPLEMENTATION OF SUPERFUND
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The SSMP quality assurance/quality control plans provide a de-
scription of the procedures for systematic control and cross-
checking of all aspects of the data collection process, including
the adequacy of the measurement or sampling program as well
as laboratory controls addressing analytical accuracy and precis-
ion. Together the plans provide relevant information similar to
that provided in the Remedial Investigation Plans used by the
U.S. EPA. The plans are being submitted to the U.S. EPA and
to the state authorities for review and comment before begin-
ning the CEARP Phase 2B individual site characterization ac-
tivities.
Phase 2A—Reconnaissance Sampling
Reconnaissance sampling is being conducted as part of the
CEARP Phase 2A SSMP development process. The reconnais-
sance sampling program provides preliminary data as appropriate
for better SSMP sampling plans design. The degree of recon-
naissance sampling conducted depends on the information avail-
able for a specific site and may include followup site inspections,
geophysical surveys, direct measurements of radiation or contam-
ination levels and/or collection of samples for analysis.
The reconnaissance sampling program provides useful input to
the development of the SSMPs and site characterization/remed-
ial investigation activities. Because of limited historical records
for many of the sites, followup site inspections, vegetation analy-
sis, geophysical surveys (primarily ground penetrating radar and
magnetometer) and aerial photography are being used to locate
and map potential subsurface sites. Although site boundaries
often cannot be clearly delineated from reconnaissance methods,
the areal extent of the sites can be better defined for scoping the
site characterization effort.
Because of the nature of the installations being investigated,
the CEARP reconnaissance sampling program also provides use-
ful information on the presence of pyrophoric metals (e.g., uran-
ium) and/or high explosives/propellants that will require special
consideration during the site characterization effort. In particu-
lar, the presence of pyrophorics/high explosives/propellants can
limit both the investigation techniques and the equipment used
during both reconnaissance and site characterization field inves-
tigations. If the site contains high explosives/propellants that
could be pressure, shock, spark or electrical impulse sensitive,
the site may have to be sampled by remote operations. This sam-
pling could involve conducting geophysical surveys, drilling or
coring by remote control from protective bunkers or safe dis-
tances. These safety hazards are addressed in the SSMPs and
are revised as additional site information is collected.
Phase 2B—Site Characterization
CEARP Phase 2B site characterization activities are being
conducted on a priority basis across all U.S. DOE-AL installa-
tions. Sites are prioritized according to the following criteria:
(1) sites where contamination levels could result in near term ex-
posures to on-site personnel or the public; (2) sites judged to have
significant potential for migration of contaminants off-site; or
(3) sites that present regulatory concerns.
Major CEARP Phase 2B site characterizations have been in-
itiated at several CEARP sites. Sites selected for initial character-
ization were chosen because of groundwater contamination prob-
lems or potential surface water migration pathways that could
potentially result in off-site transport of contaminants. The site
Table 1
U.S. DOE-AL Installations
DOE-AL W*tpoiu Production FfccililU
Pin.llu mlcmUcironlc*
•1*1 ftbticttton
ftbriettidff
bleb uplo*i*M
Iritlum
Plutonium
piutmlum
unaium
b-num
d
-------
Safety Improvement Using Simulation and Advanced
Control in Hazardous Waste Incineration
S.K. Shoor
R.J. Clinton
Combustion Engineering Simeon, Inc.
Bloomfield, New Jersey
ABSTRACT
Due to the widely varying rates and characteristics of the waste
streams, safe, efficient and stable operation of a hazardous waste
incineration facility is a complex and demanding task. This paper
describes how a well-conceived computer optimization/advanced
control and management information system can be a significant
aid to improving plant performance and reliability. Such sys-
tems have been employed extensively in the process industries
such as oil refining, petrochemicals and chemicals with excellent
results in terms of improved profitability and safety. The com-
puter-based management information system is specially suited
for this type of facility due to constantly changing feeds and is
highly beneficial for inventory control, cost accounting, main-
tenance scheduling and statutory reporting requirements.
The paper also describes how improvement in worker safety,
on-stream time and plant performance can be achieved through
an effective training program using dynamic training simulators.
With the aid of the simulator, the operator can learn to cope with
emergencies and upset conditions in a highly effective manner,
minimizing the possibility of equipment damage, personal in-
jury and harmful discharge to the atmosphere.
INTRODUCTION
Hazardous waste incineration plants are rapidly gaining im-
portance due to increased need and their ability to treat a variety
of waste streams in a highly effective manner. The waste streams
range from waste gas to solid material and can vary consider-
ably in composition as well as rate, depending upon the source
and history of the waste. Under these circumstances, it is a chal-
lenge for even the best operators to maintain a stable, efficient
and risk-free operation.
The application of optimization/advanced control and on-line
data base management can significantly improve plant profitabil-
ity through increased throughput and higher efficiencies. In addi-
tion, there are significant benefits in terms of improved plant
safety and reliability, since a more precise control is achieved and
the effect of disturbances is minimized. The use of real-time
dynamic simulators for training allows the operator to become
well-versed in coping with emergencies and upsets.
DESCRIPTION OF HAZARDOUS
WASTE FACILITY
The design of a hazardous waste incineration facility can vary
depending upon the source, type and composition of the waste
streams. This paper is based on a typical configuration suitable
for the disposal of multiple wastes including gases, liquids,
sludges and solids. A block diagram of the facility is shown in
Fig. 1.
4 IMPLEMENTATION OF SUPERFUND
v«it v«n
J
Figure I
Block Diagram of a Hazardous Waste Incineration Facility
Liquid feeds and sludges are fed to storage tanks that are re-
served for specific types of waste, e.g., high BTU, medium BTU,
aqueous or sludge. Solid wastes are stored either in bulk or in
drums or fiber packs. The drum feed and bulk feed handling sys-
tems are designed to allow feeding into a shredder prior to incin-
eration. The incineration system consists of two units which oper-
ate in parallel: (1) a rotary kiln designed to process solids and
sludges and (2) a liquid incinerator/afterburner designed to de-
stroy liquid wastes. Aqueous and high BTU wastes can be
processed in both the kiln and the incinerator.
Flue gas from the incinerator afterburner enters a quench tower
for gas cooling, gross paniculate removal and partial acid gas
scrubbing. Fresh process water is sprayed in the top zone of the
tower for the evaporative cooling of the flue gas. The flue gas
from the quench tower is treated in the air pollution control sys-
tem for final paniculate and acid gas removal by means of gas
scrubbing. The wastewater from various units is treated in a
wastewater treatment system prior to discharge into a receiving
system, such as sewer or surface water.
OPTIMIZATION/ADVANCED CONTROL
A hazardous waste incineration facility simultaneously pro-
cesses a variety of wastes, the characteristics of which vary wide-
ly depending upon the type and source. The relative flow rate of
each stream is not fixed and must be determined so that there is
no buildup of inventory and, at the same time, the design capac-
ity of the equipment is not exceeded. Despite the changing flow
rates and waste stream characteristics, it is essential to effectively
destroy the hazardous materials. To maximize profitability it is
-------
also necessary to maximize the plant throughput and maintain
the operating parameters at optimum levels. This complex task
can be accomplished best by incorporating an advanced control
and optimization system.
Such systems have been used extensively in the process indus-
try, and their benefits in terms of improved profitability as well as
increased safety and reliability have been fully proven. For ex-
ample, optimization and advanced control have proved to be
highly beneficial to the operation of ethylene plants where mul-
tiple feeds and products make these units very complex. The
objective of an advanced control/optimization system is to form-
ulate an optimal operating plan, reduce this plan to specific in-
strument set points and maintain operation at these set points.
The optimization system to accomplish these goals can be cate-
gorized in the following manner:
• Optimization—determination of the optimal operating strategy
for the plant, including optimal set points
• Advanced Control—assurance of operation at the optimal set
points
Optimization
The rotary kiln and liquid incinerator/afterburner form the
core of a hazardous waste incineration facility. These units are
closely coupled and the interaction between them must be care-
fully considered to arrive at the optimum operating parameters.
For example, all flue gas from the rotary kiln flows to the liquid
incinerator; therefore, the operating capacity of one unit depends
upon the other. Similarly, the flow of high BTU waste must be
split between the kiln and the incinerator depending upon the
available capacity in these units and the plant inventory at a given
time.
The raw hazardous waste tankage inventory must be mini-
mized so that the maximum quantity of waste material can be
received and processed. A major task of the optimizer is to deter-
mine the relative rates of various waste streams to each unit which
maximize the plant throughput and, hence, the profitability.
These rates must be computed within the constraints of equip-
ment design and maintaining the operating parameters such as
incineration temperature, excess air, pressure drop, etc., at values
which permit efficient destruction and removal of hazardous
components.
Optimization Procedure
The optimizer determines major operating parameters using
mathematical models representing the process, thus maximizing
the plant profitability by maximizing the plant throughput and
minimizing utilities (mainly supplementary fuel), while satisfying
all environmental and equipment constraints. The limitations due
to system requirements (such as temperatures leaving the rotary
kiln, liquid incinerator and afterburner, pressure drops, and
excess air) must be built into the model. In addition, the specifica-
tions or environmental emissions with respect to NOX, CO,
SOX and Cl - must be satisfied.
The optimizer can be used in both off-line and on-line modes.
In the off-line mode, the optimizer runs independent of the plant
data base and control system and allows case studies of poltential
future operating modes. In the on-line mode, the system opti-
mizes current plant performance using the actual physical state of
the equipment and environment.
Advanced Control
After the operating targets are determined by the optimizer,
specific set points for all key variables are provided to the con-
trol system. The control system maintains the selected variables
with a minimum deviation from the set points. The system also
seeks to minimize the impact of disturbances. The basic regula-
tory control consisting of single-loop controllers usually is not
sufficient for a plant involving multiple feeds with variable flow
rates and characteristics. For such plants, advanced control
strategies involving concepts such as feedforward, decoupling,
variable PID, cascade, etc., should be utilized. It is also highly
beneficial to use mathematical models and/or analyzer data to
control a given unit. Examples of advanced control strategies for
major areas of the plant follow.
Tank Farm and Waste Preparation
The objective is to maximize the quantity of the wastes that can
be received, categorize them based on heating values and ensure
that a given waste stream is stored in a tank whose contents are
compatible with it. Based on input values for the waste charac-
teristics such as heating values, hazardous component analysis,
specific gravity, ash content and viscosity, etc., and by means of
appropriate models, the computer-based system determines the
following information:
• Destination of the waste stream with respect to the storage
tank
• Status of blending of waste material in a given tank
• Specific characteristics of waste material in a given tank
• Best sequence in which to transfer the waste material to the in-
cinerator
Rotary Kiln
The key operating parameters such as feed rates, combustion
air and kiln temperature determined by the optimizer become set
points for the advanced control system. The fine-tuning of the
waste combustion air flow is performed by the final oxygen ana-
lyzer. The injection of the solid waste to the kiln is on a batch
basis, resulting in pulsation of the heat input which must be
appropriately compensated by the high BTU waste or fuel oil
flow controller.
The flow of the high BTU waste stream determined by the
optimizer to maintain a specific kiln temperature is used as the
set point of the flow controller, provided a sufficient quantity
of this material is available. If not, then the flow rate of the sup-
plementary fuel oil must be used. An important goal is to min-
imize the quantity of the supplementary fuel oil.
An appropriate residence time of the feed material must be
maintained in the rotary kiln to ensure complete incineration.
Based upon the characteristics of the feed material, a residence
time is calculated by an algorithm which then determines the kiln
speed. This value becomes the set point of the speed control sys-
tem.
Liquid Incinerator and Afterburner
The main process function of the liquid incinerator is to incin-
erate the medium BTU waste, waste gas, aqueous waste and high
BTU waste. The combined flue gas from the rotary kiln and the
liquid incinerator is sent to the afterburner. The entire quantity of
waste gas must be incinerated in the incinerator at all times to
maintain a constant header pressure. The flow rates of other
waste streams are set by the optimizer.
If the required quantity of high BTU waste is not available, the
supplementary quantity of fuel oil is calculated by the computer
and is used as the set point of the fuel oil controller. The com-
bustion air requirements calculated using the heating values of
various streams are used as set points for the combustion air flow
controller. An oxygen analyzer in the final stack resets the com-
bustion air flow controller as required.
The control systems for the other parts of the plant are rela-
tively straightforward.
Benefits of Advanced Control/Optimization
The benefits gained from the application of advanced control
IMPLEMENTATION OF SUPERFUND
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and optimization are summarized below.
Capacity
The advanced control and optimization system allows more
stable operation and higher rates closer to equipment constraints.
Experience from the process industry indicates that an increase in
throughput of 5 to 10% can be expected by incorporating ad-
vanced control and optimization.
Energy Efficiency
Incorporating advanced control and optimization concepts can
significantly reduce the energy consumption of a hazardous waste
incineration plant. Although the actual savings are a function of
the specific design and operating data, our analysis shows that
approximately 5% of energy consumption in the rotary kiln and
liquid incinerator can be saved.
Reliability and Safety
The advanced control and optimization concepts allow more
precise control of operating variables to minimize the effects of
disturbances, thereby improving plant reliability and safety. For
example, in the operation of the rotary kiln and liquid incinera-
tor, an accurate control of temperature and excess air is assured
at all times and automatically compensates for the characteristics
and feed rate of waste streams. This control system minimizes
the possibility of explosive mixtures in both the rotary kiln and
liquid incinerator, while ensuring complete destruction of haz-
ardous materials.
Advanced control can minimize the number of shutdowns by
detecting an upset quickly and taking the appropriate action or
by forewarning the operator.
PLANT MANAGEMENT AND INFORMATION
SYSTEM
A hazardous waste incineration facility is associated with exten-
sive statutory reporting requirements which make it essential to
monitor and record a substantial amount of operating data. In
addition, there are internal reporting requirements with respect
to feed rates, energy usage, maintenance, inventory control and
cost accounting. A computer-based plant management and in-
formation system can greatly simplify the task of recording and
reporting. It also can provide valuable information to manage-
ment with respect to the causes of equipment malfunction and
process upsets, permitting improvement in plant design and oper-
ating procedures to enhance plant safety and efficiency.
Federal and state regulations also require that certain operating
records be maintained and retained until closure of the facility
(20 years or more). This record keeping can be accomplished
efficiently by means of the computer-based management in-
formation system. Such a system also can include an emergency
response program which will provide alarms, information and
guidance to plant personnel and public emergency groups in the
event of a hazardous occurrence.
TRAINING SIMULATOR
The safe and efficient operation of a modern hazardous waste
incineration facility requires highly developed operating skills due
to both the complexity and wide range of compositions and flow
rates of the feed streams. The use of a training simulator which
replicates the dynamic performance of the plant can be a signifi-
cant aid in developing these skills. Simulators have been used ex-
tensively in the airline industry for many years and are now recog-
nized as the ultimate training tool in the process industry.
Most modern hazardous waste incineration facilities exhibit a
high degree of interaction, making it essential that the operators
become fully conversant with the process and operating pro-
cedures. The simulator can assist in a variety of other tasks, such
as control system checkout, development of more effective oper-
ating procedures and engineering studies. The training of oper-
ators prior to plant commissioning ensures smooth and efficient
startup with maximum safety and minimum environmental emis-
sions.
Simulator System Objectives
The objective of the simulator is to provide three levels of train-
ing which:
• Teach the operator the basic skills necessary to perform con-
trol actions and to obtain information through the use of the
displays and keyboards
• Familiarize the operator with normal operating values for all
the fundamental indication and control loops
• Simulate a set of typical process upsets and equipment mal-
functions to provide experience in problem analysis and subse-
quent corrective action; operators also learn and practice the
correct procedure for plant startup and shutdown.
These training objectives are accomplished by a simulation sys-
tem which integrates hardware, system software, simulation soft-
ware and process models to realistically simulate a process. The
degree of interaction between all components of the simulated
plant can be nearly the same as that for all components of the real
plant. The complexity of each model component can vary, de-
pending upon its importance to plant operations.
Simulator Components and Configuration
The basic components of a typical simulator system shown in
Fig.2 are:
• Simulation software
• Process models
• Simulation computer
• Trainee station
• Instructor station
Figure 2
Simulator Components
Simulation Software
Various types of dynamic simulation techniques are available
in the industry. Combustion Engineering Simeon's process mod-
els are based on a proprietary GEPURSrM software. GEPURS
software is designed to simulate dynamically any process in real
time. It is based on a block structure which permits the develop-
ment of the dynamic process model without the need to record
IMPLEMENTATION OF SUPERFUND
-------
the program or compile after every change.
The interactive and on-line features provided by GEPURS
software ease the model development effort significantly. A pro-
cess consists of many dynamic elements which are physical pieces
of process equipment or simple arithmetic equations (such as
summation, integration and first order lead/lag). In block-struc-
tured software, each dynamic element is represented by a
"block" that executes a series of calculations.
Process Model
As described above, the software-based process model repli-
cates the interacting dynamic behavior of the actual plant. Once
the plant is started up, the plant engineers can tune and modify
the model as required to adhere to physical changes in the plant
or to conform to subtle dynamic plant responses that differ from
the model.
Simulator Computer
The simulator computer can be 32-bit or 16-bit, depending
upon the complexity of the model and various peripherals.
Emulated Trainee Station
The emulated trainee station design depends upon the type of
instrumentation used in the actual plant. The emulator replaces
the actual operator station with a trainee station similar in appear-
ance to and having the same capabilities as the actual instrumen-
tation. A faceplate type control panel also can be provided de-
pending on the type of instrumentation and training needs of a
specific plant.
Instructor Station
The instructor station lets the instructor control the simula-
tion and monitor the status of the simulated process. From this
station, the instructor can see all the process information avail-
able to the trainee, as well as certain key "internal" process vari-
ables. There are also "menu-driven" displays that allow the in-
structor to load, freeze and snapshot models and to insert mal-
functions. The instructor station consists of a color graphic in-
structor terminal with a function button keyboard, which can
produce tabular displays, trend displays and P&I style process
overview displays. Displays show real-time data from the model.
Major Benefits of the Training Simulator
• The operators become thoroughly familiar with the operating
procedures, substantially reducing the startup time
• On-stream time significantly improves because operators are
better equipped to respond to emergencies and process upsets
• The training simulator provides a means to evaluate new con-
trol schemes and operating procedures
• The training simulator provides realistic operator training with-
out risking plant upsets or production losses associated with in-
plant training.
CONCLUSION
The application of advanced control and optimization systems
to a hazardous waste incineration facility can greatly enhance
plant profitability by improving plant safety, on-stream time and
energy efficiency. The use of such a system should be seriously
considered at the project planning and design stage so that an
appropriate instrumentation system can be selected.
The computer-based management and information system can
greatly simplify the task of recording and monitoring the substan-
tial amount of operating data which are needed to meet the fed-
eral and state requirements for record-keeping and reporting. The
use of a dynamic simulator has significant benefits in terms of re-
duced startup time, improved plant safety and longer on-stream
time.
IMPLEMENTATION OF SUPERFUND
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Deleting Sites from the National Priorities List
u.s
Amelia Z. Heffernan
Kathleen A. Hutson
Booz, Allen & Hamilton Inc.
Bethesda, Maryland
Steven C. Golian
Environmental Protection Agency
Washington, D.C.
ABSTRACT
The inclusion of sites on the National Priorities List (NPL) is
the first step in the Superfund remedial process. This process in-
volves sequential steps including the remedial investigation/feasi-
bility study, Record of Decision, remedial design and remedial
action. The process concludes with deleting a site from the NPL,
following a determination that the site meets one or more of the
deletion criteria described in section 300.66(c)(7) of the National
Oil and Hazardous Substances Pollution Contingency Plan
(NCP).
The U.S. EPA has developed procedures for deleting sites from
the NPL. These procedures focus on notice and comment at the
local and National levels and ensure a sound technical basis for all
deletion decisions. The focus of this paper is on the deletion pro-
cedures described in the recent draft "Guidance on Deletion of
Sites from the NPL." Specifically, it defines the classification of
completions for NPL sites, reviews the deletion criteria in section
300.66 of the NCP and the technical evaluation of deletion can-
didates and describes the overall administrative process.
INTRODUCTION
Under Section 105 of CERCLA, the U.S. EPA maintains a
National Priorities List (NPL) of hazardous substance sites. In
addition to the inclusion of new sites to the NPL, the Agency in-
tends to delete sites from the list that have been determined to no
longer present a significant threat to public health or the environ-
ment. The deletion of sites from the NPL will serve to notify the
public of Agency actions and should provide an incentive for
cleanup response to private parties and public agencies.
The U.S. EPA issued Interim Procedures for Deleting Sites
from the NPL on Mar. 27, 1984. As a result of amendments to
section 300.66 of the NCP and experience gained from the dele-
tion of 8 sites on Mar. 7, 1986, the U.S. EPA has developed a
draft final deletion guidance. This guidance reflects the NCP
amendments which no longer preclude the U.S. EPA from re-
turning to a deleted site to expend fund monies. The deletion pro-
cedures emphasize notice and comment at the local and National
levels and ensure a sound technical basis for all deletion decis-
ions. This paper summarizes the procedures described in the
draft "Guidance on Deletion of Sites from the NPL."
DETERMINING SITE COMPLETIONS
The U.S. EPA will identify deletion candidates from those
NPL sites (remedial, removal and enforcement) that have first
been classified as completions. This classification is based, for the
most part, on whether all required response actions (e.g., con-
struction activities) are completed and performance monitoring
has commenced. In some situations, completed remedial and
enforcement sites will not qualify immediately as deletion can-
didates and will remain on the NPL until performance standards
are met. These sites may be classified separately as long-term
responses (LTRs). Regions are responsible for determining
whether completed sites qualify as deletion candidates or should
be categorized as LTRs until deletion is appropriate. Fig. 1 illus-
trates this decision process.
Sites classified as completions will receive a "C" status code
on the NPL. The necessary stages in the remedial and removal
processes before an NPL site may be classified as a completion
are illustrated in Fig. 2. Specific requirements for remedial, re-
moval and enforcement sites are discussed below.
Figure 1
Process to Determine Site Disposition
IfttAl MTI • Mhftt •tttMlt MIT
Figure 2
Completion Administrative Process
Remedial Sites
Remedial sites include "no-action" sites and sites where remed-
ial actions are implemented. The latter are considered as com-
8 IMPLEMENTATION OF SUPERFUND
-------
pletions when all remedial actions, as described in the Record of
Decision (ROD), have been completed and performance moni-
toring has commenced.
"No-action" sites are considered as completions once it is de-
termined that (1) no response is necessary to protect public health
and the environment and (2) the no-action ROD has been ap-
proved. The determination that the no-action alternative protects
public health and the environment will require adequate assess-
ment of all appropriate media (e.g., soils, air, surface water and
groundwater) to ascertain that levels are safe for each exposure
pathway.
Removal Sites
For the purpose of this paper, "removal" refers to those NPL
sites where a removal action is the only response action neces-
sary to effectively clean up the site. Removal sites are considered
as completions once: (1) it is determined that no further removal
actions are required, (2) confirmatory sampling determines that
taking remedial response action is not appropriate and (3) the
ROD for no further action has been approved.
Regional remedial staff are responsible for reviewing On-Scene
Coordinator (OSC) final reports to determine if remedial re-
sponse is needed. This review process will require an analysis of
all confirmatory sampling to ascertain whether there is a signifi-
cant threat to public health or the environment. Evaluations
should focus on identifying any limitations in the data and
whether the data are sufficient to justify a decision that no signif-
icant threat to human health or the environment exists and that
no further response actions are necessary.
Enforcement Sites
Enforcement sites include Federal and state enforcement-led
sites and Federal facility sites which are classified as completions
as defined above for remedial and removal sites. These sites also
are required to have approved decision documents detailing how
cleanup criteria have been met in order to qualify as a comple-
tion (i.e., Enforcement Decision Documents (EDDs) for Federal-
led enforcement sites and Compliance Agreements, or an equiv-
alent, for Federal facilities and State enforcement-led sites).
LONG-TERM RESPONSES
Some remedial and enforcement sites that are classified as com-
pletions will not immediately qualify as deletions and will remain
on the NPL until performance standards are met. These sites may
be classified separately as LTRs. U.S. EPA Regions are respon-
sible for designating sites as LTRs prior to the promulgation of a
final NPL rulemaking.
Examples of situations where completed sites may be placed in
the LTR category include:
• Long-term remedial action is required, such as groundwater
extraction and treatment
• Institutional controls necessary for the effective performance
of the remedy or protection of public health have not been put
in place by local and/or State governments
• The effectiveness of the remedial action has not been verified
NPL DELETION CRITERIA
Section 300.66(c)(7) of the NCP (50FR 47912) provides that
sites may be deleted from, or recategorized on, the NPL when
"no further response is appropriate." To delete a site, the
Regions and Headquarters must determine whether one or more
of the following deletion criteria have been met:
• The U.S. EPA, in consultation with the state, has determined
that responsible or other parties have implemented all appro-
priate response actions required.
• All appropriate Fund-financed response under CERCLA has
been implemented, and the U.S. EPA, in consultation with the
state, has determined that no further response by responsible
parties is appropriate.
• Based on a remedial investigation, the U.S. EPA, in consulta-
tion with the state, has determined that the release poses no
significant threat to public health or the environment and re-
medial measures are not appropriate.
These deletion criteria are not intended to establish specific
monitoring requirements or performance criteria. Site-specific re-
quirements and criteria are incorporated into the design of re-
sponse actions for each site as post-closure monitoring, confirm-
atory sampling and operation and maintenance plans.
Deletion of a site from the NPL does not preclude eligibility
for subsequent Fund-financed or Potentially Responsible Party
(PRP) actions. Section 300.66(c)(8) of the NCP states that Fund-
financed response actions may be taken at sites that -have been
deleted from the NPL if future conditions warrant such actions.
Depending upon releases from liability contained in the consent
decree or administrative order, future enforcement action may be
taken if necessary.
TECHNICAL EVALUATION OF
DELETION CANDIDATES
In order to determine that one or more of the deletion criteria
have been met, the Region will perform a technical evaluation of
the data generated from performance monitoring and/or con-
firmatory sampling. These data must demonstrate that the rem-
edy has achieved the cleanup levels chosen for the site as defined
in the ROD, EDD or an equivalent decision document. If the no
action alternative is selected, data must confirm that the site poses
no significant threat to public health or the environment.
More specifically, technical documentation and data for any
site must demonstrate that:
• Groundwater is safe to drink and does not pose a threat to en-
vironmental receptors or that controls/treatment achieve the
degree of cleanup or protection specified in the ROD/EDD
and outlined in the groundwater protection strategy for the
classification or affected groundwater
• Soils/waste do not affect the achievement of cleanup objec-
tives specified for other environmental media (e.g., ground-
water, surface water or air) and that the direct contact threat
is at an acceptable risk
• Air emissions are protective of public health and the environ-
ment as defined in section 112 of the Clean Air Act (CAA)
and the 1977 CAA amendments for primary and secondary
major criteria pollutants
• O&M specified for a site is guaranteed by the state or PRP and
is sufficient to maintain the effectiveness of the source control
remedy and performance objectives
• Institutional controls necessary to protect public health and the
environment and for the effective performance of the remedy
are in place
For pollutants without established standards, an assessment of
risk will be necessary to determine that exposure levels are pro-
tective of public health and the environment (i.e., range 10~4 to
10-7).
Prior to deleting a site, the U.S. EPA will make a determina-
tion that the remedy or the decision that no further response ac-
tion is appropriate and is protective of public health and the en-
vironment. This determination will take into consideration Fed-
eral and state environmental requirements which are applicable or
relevant and appropriate to CERCLA response actions at the time
IMPLEMENTATION OF SUPERFUND
-------
of deletion. If cleanup standards/criteria have changed since the
remedy was chosen, the lead agency or PRP will do a site assess-
ment to evaluate the need for additional response actions to meet
current standards/criteria.
DELETION ADMINISTRATIVE PROCESS
The administrative process for deleting sites from the NPL is
illustrated in Fig. 3 and summarized below.
Initiation of the Process
Regions will initiate the deletion process by consulting with
states and obtaining their concurrence on the Agency's intent to
delete a site. In some cases, the state or PRP may initiate this
process by specifically requesting the deletion of a site. Follow-
ing state concurrence, Regional staff will brief the Regional Ad-
ministrator (RA) on the status of cleanup response at the site and
obtain the RA's approval to proceed with deletion.
Figure 3
Deletion Administrative Process
The Regions will prepare a deletion docket containing all perti-
nent information supporting the Region's deletion recommenda-
tion. A complete deletion docket will be maintained in the
appropriate Regional public docket and local repositories before
the Region publishes the Notice of Intent to Delete.
Public Notices and Response to Comments
Once the deletion docket has been established, the Region will
prepare a Federal Register notice of the Agency's intent to de-
lete a site'and will provide U.S. EPA Headquarters with a copy
for review and comment. This National notice will describe the
Agency's deletion criteria and provide: (1) the location of the
Regional dockets, (2) request for public comments for a 30-day
period and (3) description of site history, response actions, clean-
up standards and criteria and other site-specific information per-
tinent to the deletion of the site.
The Region also will prepare the local Notice of Intent to De-
lete. This statement is distributed to community, state and local
officials; appropriate Federal agencies; enforcement personnel
from the Office of Regional Counsel (ORC); and any local reposi-
tories. In addition, the ORC will inform the State Attorney Gen-
eral and other interested agencies of the possible deletion. The
local notice will provide the same information contained in the
National notice.
Regions are responsible for preparing responsiveness sum-
maries of local and National comments including the Agency's
responses to the comments. Headquarters will assist the Regions
in preparing responses to those comments which address issues of
National concern. Regions will send copies of comments received
in response to the local and National Notice of Intent to Head-
quarters.
The responsiveness summary also may provide justification for
proceeding with the deletion if public comments indicate strong
disagreement with the recommendation. If significant comments
are received, Regions may elect to delay publication of the de-
letion until the issue(s) are resolved. Regions will include a copy
of the responsiveness summary, approved by the RA, in the Reg-
ional public docket.
Publication of Deletions
Regions will prepare a draft Federal Register notice to an-
nounce the deletion of sites from the NPL which will include a
summary of the comments received from the Notices of Intent to
Delete (local and National) and the Agency's responses. Reg-
ions will submit the Notice of Deletion and Action Memorandum
to the Assistant Administrator, Office of Solid Waste and Emer-
gency Response (AA, OSWER) for concurrence and publica-
tion. Any supporting documents relating to specific Agency re-
sponses to public comments also will be submitted. The AA,
OSWER will publish the Notice of Deletion in the Federal
Register, and final NPL rulemakings that occur after its publica-
tion will reflect the deleted sites.
CONCLUSIONS
The U.S. EPA's final deletion procedures, by establishing
specific requirements for the technical review and evaluation for
all response actions at NPL sites, will ensure a sound technical
basis for all deletion decisions. Because the deletion of sites from
the NPL will become increasingly important as more remedial
actions are completed, public agencies and private parties should
be familiar with the criteria, documentation and administrative
procedures described in the deletion guidance in order to effec-
tively participate in the deletion process.
10 IMPLEMENTATION OF SUPERFUND
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Implementation of Superfund:
Community Right-to-Know
Jim Makris
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Washington, B.C.
ABSTRACT
The tragedy of Bhopal focussed the attention of the American
government, citizens and industry, on the fact that there is a real
potential for serious, devastating chemical accidents. Congress
acted by including requirements in Superfund reauthorization
for industry and government to make information available to
the public regarding the potential threat from hazardous chem-
icals in their community. Additionally, requirements are pro-
posed for communities to develop contingency plans to address
the possibility of chemical emergencies. The U.S. EPA supports
community right-to-know and has worked with Congress to
develop this legislation.
To provide guidance to states and local communities in the
identification of chemical hazards and preparation for these
potential threats, the U.S. EPA announced the Chemical Emer-
gency Preparedness Program (CEPP) in December 1985. CEPP
provides guidance, training and technical assistance to states and
local communities to help them meet their responsibilities to pre-
pare for and respond to chemical accidents. The guidance assists
states and local communities in organizing the community; in
eliciting site-specific information from industry to identify poten-
tial hazards; and in developing and exercising contingency plans.
In order to assist communities in using the CEPP guidance, the
U.S. EPA developed criteria and a list of acutely toxic chem-
icals that would cause serious health effects or death during a
short term, high level exposure if released accidentally.
Guidance, training and technical assistance are being provided
to state officials and, through states, to local officials to help
them identify potential hazards and develop adequate contin-
gency plans. This guidance also will help implement community
right-to-know provisions of the Superfund reauthorization.
Courses in contingency planning, conducting simulations and
developing hazardous materials teams are available through U.S.
EPA offices, FEMA Regional offices and the state governments.
These CEPP activities are consistent and complement the com-
munity right-to-know and emergency preparedness requirements
of Superfund reauthorization. Currently, the U.S. EPA is laying
out approaches to implement these provisions and will discuss
them at the conference along with the status of the CEPP.
INTRODUCTION
The tragedy in Bhopal, India, an event that occurred halfway
around the globe, shocked the United States and the rest of the
world into recognizing the enormous potential threat that exists
for chemical accidents. Bhopal stimulated an aggressive series of
actions to develop and modify programs dealing with the preven-
tion of and response to such accidents.
The message is clear—no matter how good the intent to miti-
gate chemical disasters, to deal with the causes of chemical disas-
ters and to control the conditions surrounding a potential chem-
ical disaster—accidents will still happen and we must be prepared
to respond. The U.S. EPA's programs are intended to reduce the
possibility of such events and to improve the ability of state and
local officials and emergency managers to meet their responsi-
bilities in preparing for and responding to chemical accidents.
Some say that the U.S. EPA's Air Toxics Strategy announced
by the Administrator in the summer of 1985 was simply a reac-
tion to Bhopal. All of us know that events such as Bhopal, the
'release of uranium hexafloride in Gore, Oklahoma, or the radio-
logical release in Chernobyl do not cause us to "start" but rather
to renew our existing efforts with greater force and resolve. The
Air Toxics Strategy consists of a series of initiatives dealing with
routine emissions and a program targeted toward accidental
chemical releases. This latter program became known as the
Chemical Emergency Preparedness Program (CEPP).
CEPP consists of a series of programs designed to increase
community awareness of chemical hazards and to develop or en-
hance state and local emergency preparedness plans for dealing
with chemical accidents.
EXISTING PRE-BHOPAL INITIATIVES
At the outset, it is essential to note that the possibility of a
chemical accident in the United States and the need to prepare for
such a contingency did not start after Bhopal. There have been
preparedness activities in all levels of government—state, local
and Federal—as well as in the private sector for many years. It is
in full recognition of the always present possibility of accidental
chemical releases that several very specific mechanisms have been
in place:
• CHEMTREC and the National Response Center
• The National Contingency Plan (NCP), originally designed for
oil spills but later expanded to include hazardous materials
• The National Response Team/Regional Response Teams
• Reportable Quantity Provisions in CERCLA
However, it also must be noted that an enormous paradox
exists. While there is a continuing and persistent potential for a
chemical disaster—after all, large quantities of acutely toxic
chemicals are stored, used and transported throughout the na-
tion and the world—nevertheless, a tragic release from a chem-
ical facility has not occurred in this country for many years nor
have very many occurred throughout the rest of the world; one
can count the major chemical disasters on a single hand—Texas
City in 1947; Flixsborough, England in 1974; Seveso, Italy in
1976; Mexico City in 1984 and Bhopal, India in 1984. However,
the Bhopal event triggered a great many concerns regarding the
IMPLEMENTATION OF SUPERFUND 11
-------
possibility of a chemical accident in the minds of the American
public. A recent Roper Poll reported that 2 out of 3 Americans
believe that a major chemical tragedy will occur in the United
States within the next 50 years.
THE CHEMICAL EMERGENCY
PREPAREDNESS PROGRAM
While government and industry have approached the problem
from different perspectives, the Chemical Manufacturers Asso-
ciation's Community Awareness and Emergency Response
(CAER) program and the CEPP both were developed to address
specific concerns; concerns expressed by citizens who want to
know what they should do to protect themselves; concerns ex-
pressed by state and local officials seeking guidance and assis-
tance to revise their programs or initiate new ones where none
exist; concerns expressed by industry taking progressive steps to
increase safety; and concerns expressed by Congress demanding
action.
The CEPP consists of the following:
• Increased federal coordination and technical assistance to state
and local governments
• A list of acutely toxic chemicals, criteria and chemical profiles
• A series of guidance documents
• Increased enforcement of existing laws regarding accidental re-
leases
This effort does not involve the reinvention of any new wheels
or the development of duplicative mechanisms in regard to pre-
paredness activities for chemical accidents; to the contrary, it
builds upon existing mechanisms. To the extent that planning
organizations exist in states and local communities, they should
be energized and asked to proceed with their programs, to re-
view their priorities and to focus on those issues of greatest con-
cern. If plans exist, communities should review them, exercise
them and modify them appropriately. If a planning structure does
not exist, the community should establish one which includes all
the appropriate members of the community, i.e., first respond-
ers, emergency medical officials, chemical engineers, public
media, union and industry representatives, etc.
Since the release of the Chemical Emergency Preparedness Pro-
gram Interim Guidance last December, over 24,000 copies have
been provided to states and local communities as well as indus-
try and foreign governments. The CEPP Hotline has handled
thousands of calls from state and local officials, industry and
interested citizens in its first 9 months.
The U.S. EPA formally requested public scrutiny of its Interim
Guidance document and used all comments in the revision of the
guidance. Of course, this document also will include appropriate
requirements of Title III of the Superfund reauthorization. Most
of the comments received dealt with the list of acutely toxic chem-
icals, the criteria and the quantity determination model. How-
ever, major substantive changes to the planning guidance docu-
ments were not required. Furthermore, in response to the requests
of many state and local officials, several Federal Agencies, which
are members of the National Response Team, have agreed to
jointly issue unified Federal Guidance for preparedness planning
for chemical accidents. This revised guidance will replace several
agencies publications, including the popular "FEMA 10" Check-
list.
TRAINING AND TECHNICAL
ASSISTANCE AVAILABLE
To assist in the implementation of the CEPP, training and tech-
nical assistance are being developed for state officials and,
through the states, for local officials to help them identify poten-
tial chemical hazards and to develop adequate preparedness and
response capabilities. Courses in contingency planning, in con-
ducting simulations and exercises and in developing hazardous
materials teams are available. These training offerings have been
fully coordinated with FEMA, other Federal agencies and the
private sector, including the Chemical Manufacturers Associa-
tion (CMA) and its CAER program.
The NRT and RRTs will be the Federal forum for coordinat-
ing these preparedness technical assistance and training activities.
While government at all levels must be prepared to provide what-
ever assistance is required—whether it be training, technical con-
sultation or a question answered by a state or U.S. EPA regional
official or the U.S. EPA's national CEPP hotline—effective
implementation and the responsibility for dealing with the issues
remains local. Therefore, training and technical assistance must
be coordinated and developed in response to a local area's spe-
cific needs.
OTHER RELATED PREPAREDNESS
ACTIVITIES
U.S. EPA Administrator Lee Thomas has directed the Agency
to explore issues related to the prevention of chemical releases as
part of an overall effort to increase chemical safety and protect
the public health and the environment. In this context, the U.S.
EPA is continuing to gather information to expand knowledge
of the problems associated with accidental releases and their
causes as well as to encourage and facilitate prevention activities
undertaken by other Federal agencies, states, local governments,
private industry and professional organizations.
As part of this effort, the agency has developed a process for
gathering detailed information regarding specific accidental re-
leases which also will provide data on preventive measures taken
by industry following such events. This effort builds on the in-
formation gained through the reportable quantity requirements
ofCERCLA.
CEPP is designed as a voluntary program. The Congress, how-
ever, in Title III of the reauthorization of CERCLA, has legis-
lated Right-To-Know and emergency preparedness provisions
which are complementary to and consistent with CEPP but add
specific enforcement provisions. In implementing this complex
legislation, the agency will build upon the policies, analyses and
guidance which have been developed and used in implementing
CEPP to the extent possible.
This legislation is geared for implementation at the state and
local levels of government and require the establishment of state
commissions and local planning committees to assist in the devel-
opment of emergency preparedness and response plans. This
planning requirement is based around those facilities with speci-
fied amounts of chemicals that are on the U.S. EPA's list of 402
acutely toxic chemicals. Guidance on contingency planning will
be developed by the NRT, and plans may be reviewed and assis-
tance given to local committees by RRTs upon request.
These state commissions, local committees, local fire depart-
ments and other first responders will receive information required
under the reporting provisions of Title III. These include report-
ing provisions for emergency notification of chemical emergen-
cies, submission of Material Safety Data Sheets and information
regarding inventory of covered chemicals, including location and
quantities. In addition to these requirements, information must
be submitted by covered facilities to U.S. EPA on emissions in-
ventories. This information will be used as an aid in research and
development of regulations and will be computer accessible.
12 IMPLEMENTATION OF SUPERFUND
-------
CONCLUSIONS must do his/her job as we work together to fashion and imple-
In conclusion, the CEPP* constitutes an aggressive move to- ment an effective program of local chemical emergency contin-
ward a comprehensive and cooperative program of response and gency plans.
preparedness involving all levels of government, the private sec- ,,f the reader has further questions or would like more information on the CEPP|
tor and the general public. The program is still in its formative he/she may call the CEPP Hotline at (goo) 535-0202 or in Washington, DC at
Stages, and all material is Still characterized as interim. Each Of US (202) 479-2449 from Monday through Friday from 8:30-4:30 (EOT).
IMPLEMENTATION OF SUPERFUND 13
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Improvements in Superfund Site Management
Christopher Sebastian
John Mateo
U.S. Environmental Protection Agency
New York, New York
Randall Kaltreider
U.S. Environmental Protection Agency
Office of Emergency and Remedial Response
Washington, D.C.
Martha Monserrate
CH2M HILL
Reston, Virginia
ABSTRACT
A computerized system was developed in U.S. EPA Region II
to assist site managers in planning, monitoring and controlling
site schedules. The system was developed using commercially
available project management and data base software and exist-
ing Region II microcomputers.
The system works through the establishment of individual site
schedules by site managers. The site schedules are subsequently
combined to provide summary reports to section, branch and
regional managers. Benefits of the system include greater consis-
tency of project activity reporting, training of inexperienced site
managers and improved capabilities for program managers to
allocate limited resources. Future enhancements may include an
automated link to CERCLIS, the U.S. EPA Headquarters pro-
gram management system.
INTRODUCTION
During the summer of 1985 the U.S. EPA's Office of Emer-
gency and Remedial Response (OERR) decided that the Super-
fund remedial program should be reviewed to determine whether
the existing approach was adequate to meet Agency site cleanup
goals. Agency and contractor staff with extensive management
experience in both Superfund and non-Superfund programs par-
ticipated in the review.
The evaluation identified several needed improvements to the
management and conduct of site activities; a key element that
needed attention was improved planning, monitoring and control
of site project activities. The evaluation concluded that there was
a need throughout the Superfund program for the development
of project plans which focused on construction completions,
rather than just RI/FS (remedial investigation/feasibility study)
completions. The evaluation also identified a need for U.S. EPA
site managers to improve their capability to track progress and
better anticipate delays and resource conflicts.
Subsequently, Region II staff who had been working on a com-
puterized project planning system offered to lead a pilot project
designed to meet the improved project management goals set
forth in the OERR study; a second goal of the project was to pro-
vide a better means for collecting and disseminating the site man-
agement data necessary for good program management. The
Region II effort evolved into a site manager based project plan-
ning, monitoring and control (PPMC) system.
PROJECT PLANNING, MONITORING AND
CONTROL CONCEPT
There are four steps which define the PPMC concept:
• Baseline planning
• Monitoring and reporting
• Analysis
• Management action
Each step constitutes an essential element in the successful com-
pletion of a long-term program. The level of detail to which each
is applied depends on the complexity of the program and the em-
phasis placed on the three primary variables:
• Scope
• Schedule
• Cost
The U.S. EPA Superfund program includes important features
that require special consideration in developing a PPMC system.
First, the Superfund program is still evolving. New sites are iden-
tified regularly, and new solutions to toxic waste disposal prob-
lems continue to emerge. In addition, the Superfund program has
evolved in response to statutory and policy requirements. Thus,
the dynamic nature of the program complicates the development
of specific scope objectives. The PPMC process, therefore, must
be flexible and must be updated on a regular basis to stay in syn-
chronization with the changing requirements.
A second special feature of the Superfund program is the de-
centralization within the program structure. The sites are located
in all states and are managed at the U.S. EPA regional level.
Site cleanups primarily are the responsibility of individual U.S.
EPA site managers. Further adding to the decentralization of re-
sponsibility are the states, the U.S. EPA contractors, the Army
Corps of Engineers and private parties participating in various
phases of site work. These aspects of the program require that
the PPMC system be easy to implement, simple to update and
flexible in its application. Users must be free to use as much or
little of the system as necessary to accomplish their individual
objectives while meeting broader program objectives.
The third important feature of the Superfund program is the
annual preparation of program funding levels. Cost goals are
based on annual appropriations. Specific site cost targets initially
may be "educated guesses," then continuously be refined as site
14 IMPLEMENTATION OF SUPERFUND
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work progresses.
Since a prime objective of the Superfund program is to clean
up sites as quickly as possible, the emphasis in the PPMC system
should be on the schedule variable within each project. Identifi-
cation of key milestones, the time required to achieve those mile-
stones and the constraints that could cause deviations from plan-
ned schedules are major considerations in the development of the
PPMC system.
Finally, there are several basic guidelines which apply to the
development of a PPMC system for the Superfund program:
• The goal of the program is to remediate hazardous waste sites;
intermediate milestones are only checkpoints of progress to-
ward that goal.
• A plan does not define a precise end point; it merely defines the
limits of a pathway in the desired direction.
• The volume of data available makes it easy to become "lost in
the numbers" themselves, forgetting what they represent and
the level of accuracy to which they were generated.
• The simpler the planning tool and the easier to use, the more it
will be used.
The PPMC concept is to develop a plan that forms the baseline
by which all activities and performances are measured. The base-
line plan needs to encompass all the goals, criteria, limitations and
constraints imposed on the site project. It should be the best esti-
mate of the activities and resources necessary to complete the site
work available to the site manager at the time the estimate is
made. The monitoring process should be designed to report the
actual schedule and resource expenditures necessary to accom-
plish each activity within the project.
The reporting format should match the planning format such
that variances can be identified quickly and analyzed by manage-
ment. Whether the variance is over or under plan, management
must answer one key question: have conditions changed such that
the initial plan needs to be modified or can procedures be changed
to conform activities to the baseline plan at some point in the
future? The continuous process of going through these steps con-
tributes significantly to successful completion of the program.
In any program, the data base of planning and monitoring in-
formation originates with the smallest unit within the program
and is aggregated to provide reports to various levels of manage-
ment as required. As applied to the Superfund program, the
PPMC concept requires the U.S. EPA site manager to develop a
baseline site plan representing the best estimate of the activities,
resources and schedules required to complete the site work. This
information serves as the basis for monitoring site activity and
allows early identification of potential schedule and budget prob-
lems. The site manager is thus afforded the opportunity to take
management action before the problems impede site cleanup pro-
gress.
By summing this information for all sites in a region, regional
management is able to more accurately forecast program achieve-
ments and regional resource needs. At a national level, the in-
formation helps paint a more accurate picture of current pro-
gram status and trends.
This "grass roots" management concept is being implemented
in several regions. The discussion in this presentation focuses on
the efforts within Region II, where a personal computer based
system is being used by site managers to establish baseline site
schedules and monitor site activities. Project management soft-
ware is being used to facilitate schedule updates, and data base
software is being used to store schedule data and create reports.
SYSTEM DESCRIPTION
The PPMC system uses generic schedules as the basis for creat-
ing site-specific baseline schedules using commercially available
project management software. The baselines then are stored in a
regional data base, and a copy of the baseline is used to track ac-
tual site work progress. As modifications are made to the base-
line copy, it becomes the "actual" schedule or the record of the
durations for activities performed at the site. Individual site
schedules then can be combined into a variety of different man-
agement reports which eventually may be transferred electron-
ically to U.S. EPA Headquarters or other regions. The sched-
ule also may be transmitted directly to CERCLIS to become
part of the national Superfund program data base. The PPMC
system design is shown schematically in Fig. 1. Key PPMC sys-
tem elements are discussed below.
Generic and Baseline Schedules
A generic schedule includes a series of over 80 tasks and mile-
stones covering the standard RI/FS, RD (remedial design) and
RA (remedial action) activities that occur on a site before it can
be considered for deletion from the NPL. Task durations, based
on published guidance and input from experienced U.S. EPA and
contractor site managers, are chosen to represent average site
conditions. The schedule is computerized using project manage-
ment software which allows tasks to be connected by dependen-
cies so that an increase or decrease in a task duration will show the
appropriate impact on the overall schedule. A generic schedule
is maintained for each type of site lead or action, currently includ-
ing Federal-led and state-led site cleanups. Fig. 2 shows the RI/FS
segment of a generic schedule for a Federal-led site cleanup.
Figure 1
Project Planning, Monitoring and Control System Design for Region II
The purpose of the generic schedule is to aid the site manager in
initially preparing baseline plans. The generic schedule feature is
a timesaver for experienced site managers and provides guidance
to less experienced site managers. At a minimum, the generic
schedule acts as a menu of activities which must be considered in
developing a baseline site schedule.
To convert a generic schedule to an actual baseline site sched-
ule, the site manager changes the start and end dates for currently
planned activities. As schedules for specific tasks are adjusted,
the project management software will automatically adjust the
schedules for all subsequent tasks. If inadequate information is
available for out-year activities (e.g., RA tasks when the site is at
the RI/FS stage), the generic schedules for those tasks will serve
as the baseline until some future time when better information
will be available.
The site manager establishes the baseline schedule for indi-
vidual tasks in accordance with a set of standard task and mile-
IMPLEMENTATION OF SUPERFUND 15
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POP Negotiations C
Design Assist. Funds to Corps p
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Scale: Each character equals 1 week
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Jun Jul Aug Sep Oct Nov Dec Jan Feb Har Apr Hay Jun Jul
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. .K . ...
Figure 2
RI' FS Segment of a Generic Schedule for a Federal-Led Sile
stone definitions which identify specific task start and end points.
The use of standard definitions minimizes misinterpretation of
the schedule data in multi-site reports. However, the site manager
is not limited to using the pre-defined tasks. He or she may add
tasks for his or her own use in tracking site activities or may de-
lete generic tasks that do not apply. The only tasks which are
mandatory are approximately 55 tasks chosen by the regional
management and 20 chosen by Headquarters. The 20 Head-
quarters items represent a subset of the 55 regional tasks and are
key program milestone and fund obligation points. Since these
mandatory tasks are spread over the life of a site cleanup (an aver-
age of 5 yr), they represent a minimal reporting burden on the site
manager and allow the PPMC system to be used predominantly
as a site management tool.
Actual Schedules
Once a baseline schedule is established and stored in the reg-
ional data base, the site manager corrects the start and end dates
for current tasks and for those future tasks that can be more
accurately predicted. Periodically, the site manager obtains an
"alarm clock" listing of activities that are late or due. The listing
focuses attention on activities that, if not performed on time, will
lead to further schedule conflicts.
IMPLEMENTATION
The PPMC system currently is being implemented in Region II
through a user review process. The process began with the selec-
tion of a group of site managers and section chiefs. The partici-
pants' computer knowledge and management experience varied
widely. All participants were trained to use the PPMC system and
were asked to establish baseline site schedules and subsequently
monitor those schedules by submitting updates for inclusion in
the regional data base every 2 weeks.
The response of the participants has been very positive. Less
experienced project managers have benefitted from the guidance
provided by the generic schedules. For example, one site manager
noted that, through the process of building baseline schedules,
previous commitments to the completion of a Record of Decision
(ROD) by the third quarter of FY '86 were based on a schedule
much more ambitious than suggested by the generic schedule.
Using the generic schedule, the ROD would be signed later than
the fourth quarter. From a review of the specific site situation,
it was concluded that the generic schedule was, in fact, closer to
reality. This example represents a small victory, but it provides a
glimpse of the power the system can provide as a management
tool. It illustrates how resources can be focused where they are
16
IMPLEMENTATION OF SUPERFUND
-------
most needed to meet regional program targets if realistic sched-
ule data are developed and used.
Impediments to full-scale implementation in Region II are like-
ly to include a lack of interest (by some) in hands-on use of the
microcomputer. This limitation is being circumvented to some ex-
tent during the user review by having section or branch desig-
nees keep track of several sites at a time. The emerging challenge
will be to train site managers that the greatest amount of atten-
tion to site management tasks is required when the workload is
heaviest. An incentive being tried in Region II is to make atten-
tion to management details a part of the annual performance
evaluation criteria.
FUTURE GOALS
Future PPMC system work will focus on the development of
generic cost information for resource allocation and tracking and
increased reporting capabilities. In addition, linkages between the
microcomputer systems and CERCLIS are being evaluated; such
linkages would help eliminate current reporting burdens. The
electronic transfer of data among the U.S. EPA site managers,
contractors, Army Corps of Engineers and states is also being in-
vestigated to help streamline the reporting/data entry process.
One step toward this goal has been a successful effort by the U.S.
EPA and Superfund contractors to develop a common set of
RI/FS reporting tasks and milestones. Future versions of the
Region II generic milestones will reflect the contractor standard
tasks.
CONCLUSION
The purpose of the above discussion is not to reveal new con-
ceptual approaches to Superfund site project management or to
suggest a specific type of management tool. Instead, the point is
to emphasize the substantial benefits which may be gained in pro-
gram performance through simple, broad-based, "grass roots"
improvements in site schedule management. By integrating con-
tractors, states, the Army Corps of Engineers and other program
participants in this effort, information transfer can be stream-
lined and program attention may be focused less on the collection
and manipulation of management data and more on the true goal
of promoting hazardous waste site cleanups.
IMPLEMENTATION OF SUPERFUND 17
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Maximizing Cleanup Options
And Minimizing Liabilities Under CERCLA
Theodore Hadzi-Antich
New York State Environmental Facilities Corporation
Albany, New York
ABSTRACT
This paper identifies and discusses mechanisms under which
companies may maximize cleanup options and minimize liabilities
under CERCLA.' First, the paper addresses the purchase and sale
of properties that may be contaminated by hazardous substances,
and a procedure is provided to help companies ensure they do not
unknowingly purchase contaminated properties.
Second, the paper discusses steps site owners and operators
may take in response to a proposed or contemplated listing on the
National Priorities List (NPL), including specific management
procedures for and conditions of government access to privately
owned sites.
Third, the paper provides advice to generators, site owners, site
operators and transporters regarding participation on committees
of Potentially Responsible Parties (PRPs), including pros and
cons of PRPs conducting their own Remedial Investigations and
Feasibility Studies (Rl/FS), based on recent court decisions.
Fourth, the paper discusses special defenses available to gener-
ators with regard to shipments and sales of hazardous substances,
focusing on CERCLA legislative history and recent judicial
opinions.
Fifth, the paper addresses PRP settlement offers, with specific
reference to the developing CERCLA Settlement Policy and the
recent U.S. EPA policy regarding "how clean is clean."
INTRODUCTION
CERCLA authorizes the federal government to take appro-
priate cleanup or preventive actions in response to a release or a
substantial threat of a release of a hazardous substance into the
environment unless the government determines that the cleanup
actions will be performed properly by private parties who are
liable under the Act.' Government-financed cleanups initially are
paid for by a CERCLA-created fund that comprises certain fed-
eral appropriations and tax revenues.'
Generally, liability for the costs of government cleanup actions
under CERCLA may be imposed upon any person who owns or
operates the facility from which a release or threatened release
emanates, or any person who sends or transports hazardous sub-
stances to the facility.' Moreover, any liable party who fails to
provide proper removal or remedial action pursuant to a govern-
ment order may be liable for punitive damages equaling as much
as three times the amount of the response costs incurred by the
government.' In addition to cleanup costs and punitive damages,
CERCLA imposes liability for "damages for injury to, destruc-
tion of, or loss of natural resources.'"
About half of the states have enacted CERCLA-type statutes;
these laws vary considerably from state to state. Some states have
created emergency response funds for only certain spills,' while
other states have enacted provisions creating hazardous waste
funds for immediate or long-term environmental risks.' Such
risks may include active* or inactive" hazardous waste dump
sites, or, more broadly, uncontrolled hazardous substance sites."
Virtually all of the state statutes provide for at least cleanup cost
reimbursement from those panics responsible for the environ-
mental or health risks leading to state abatement actions.
The mammoth liabilities imposed by this array of federal and
state statutes have caused companies handling hazardous sub-
stances considerable problems. To a large extent, courts have up-
held the government's claim that even de minimus contributors
to hazardous waste sites are jointly and severally liable for site
cleanup. There are, however, palpable opportunities for minimiz-
ing CERCLA liabilities. This paper presents several such oppor-
tunities.
ACQUISITION OF PROPERTY
Owners of property upon which hazardous substances have
been deposited are strictly liable for its cleanup." As a result,
companies must be careful when purchasing real estate.
It makes good business sense to require an environmental audit
of any real property a company wishes to purchase. There are
four general categories of information the audit should address.
First, the prospective purchaser should review all environmen-
tal regulations affecting the property in question, including
applicable standards, guidelines and permits. A full compliance
history of the property (and any related facilities) should be out-
lined. This review should include an identification of all sub-
stances released from or to the property that are either hazardous
substances (as defined in CERCLA) or are otherwise regulated
by environmental, health or safety standards.
Second, a mass balance of all wastes produced at the site should
be performed, with specific reference to whether wastes are dis-
posed of on-site or shipped off-site for disposal. For all off-site
shipments, compliance with RCRA" must be determined.
Third, all environmental, health and safety enforcement
actions, including citizens suits and toxic tort suits, in which the
property is involved, or by which the property has been affected,
should be identified.
Fourth, the environmental organizational structure and the
environmental management practices of the seller should be in-
vestigated. Is there an Emergency Response Plan to deal with
spills and leaks? Have environmental audits previously been con-
ducted at the property? Are chemical concentrations routinely
monitored in the workplace? These are the types of questions
that need to be asked regarding organizational structure and man-
agement practices.
After conducting the above type of environmental audit of the
property, the prospective purchaser will have a good grasp of
CERCLA and other environmental liabilities associated with the
18 LEGAL/ENFORGEMENT
-------
property and thereby be able to protect itself accordingly. For ex-
ample, if the property brings with it CERCLA liability, the
prospective purchaser may still wish to purchase it subject to a
negotiated indemnification agreement. Or, the prospective pur-
chaser may wish to negotiate another transaction involving the
property, such as a lease or an easement, thereby lessening the
chances that a court will hold it liable as an owner.
SPECIAL RIGHTS OF PROPERTY OWNERS
If a company already owns a property contaminated by haz-
ardous substances, there are a number of ways to maximize clean-
up options and minimize liabilities.
The key element is active participation early in the NPL pro-
cess. The NPL process begins when the U.S. EPA identifies sites
and lists them on the Environmental Response and Remedial
Information System (ERRIS). Sites listed on ERRIS are subject
to Preliminary Assessment and Site Investigation. Data from
these assessments and investigations result in quantification of the
types of wastes and their effects on the site and its surroundings.
The data is processed through the U.S. EPA's Hazard Rank-
ing System. Sites that score higher than 28.5 are proposed by the
U.S. EPA for inclusion on the NPL followed by a public com-
ment period and possible final listing.
Owners of potential NPL sites should become involved in the
listing process as early as possible. Property owners have certain
rights, particularly during the site investigation stage. For ex-
ample, an owner may set reasonable limitations on the U.S.
EPA's entry onto the land. These may include requiring the U.S.
EPA to provide the owner with splits of any samples taken on
site,'4 copies of reports arising out of site investigation15 and
copies of field investigators' handwritten notes and photographs
taken while on-site. Moreover, the owner may require that trade
secrets coming to the attention of the investigators during a site
visit be treated confidentially." Furthermore, employees of the
site owner may accompany the U.S. EPA investigators and take
notes of their activities. Such notes may be helpful if future ques-
tions arise regarding the site investigation. On the other hand, it
would be unwise to allow the U.S. EPA investigators to question
the site owner's employees without the presence of an attorney.
In short, site owners should assert their proprietary rights during
a U.S. EPA site investigation. This will result in a better, more
complete and fair site investigation.
If, after the site investigation, the U.S. EPA proposes to list the
site on the NPL, the site owner has a right to comment on the pro-
posed listing. Generally, proposed NPL listings are subject to a
60-day comment period unless the site is listed under a public
health advisory, in which case the comment period is only 30
days.
If a site is listed on the NPL, the listing may be challenged in a
judicial action filed in the U.S. Court of Appeals for the District
of Columbia Circuit. The challenge must be made no later than
90 days after the site is listed.
PARTICIPATION ON PRP COMMITTEES
The extent to which a PRP should participate on a PRP com-
mittee is problematic. Before any decision is made regarding par-
ticipation, the PRP should thoroughly investigate its involvement
with the site in question.
Generally, a PRP who does not own the site (i.e., a generator,
a transporter or a former owner) will first become aware of its
potential liability when it receives a CERCLA Section 104(e)
letter from the U.S. EPA. Among other things, the letter, which
usually will be received after the site in question is listed on the
NPL, generally indicates that the addressee is being considered a
PRP for a particular site and requests the PRP to provide in-
formation regarding its relationship to the site.
Immediately upon receipt of the letter, the PRP must conduct
a thorough investigation. First, the PRP needs to determine if it
sent any wastes to the site in question, and, if so, if any such
wastes were CERCLA hazardous substances. If wastes were sent
to the site, there are a number of ways of showing they were not
hazardous substances. In addition to laboratory results showing
that no hazardous substances are present in the waste, the PRP's
manufacturing process may be used to show that wastes resulting
therefrom could not be hazardous. In addition, constituent parts
of the waste may be shown not to contain or react into hazardous
substances.
If the wastes sent to the site were hazardous substances, the
PRP should determine as accurately as possible the quantity of
such hazardous substances it sent to the site. Certain important
procedures should be followed by a PRP in determining the ex-
tent to which it contributed hazardous wastes to a site.
First, an experienced environmental attorney should be in
charge of the investigation. All documents generated during the
investigation should be delivered to the attorney to determine
whether any of them should be protected under the attorney-
client privilege.
Second, the attorney in charge of the investigation should
gather information from three essential sources:
• All documents relating to shipments to the site, including con-
tracts with site operators, shipping orders, bills, permits and
memoranda should be collected. From these documents, essen-
tial information must be garnered regarding the types and vol-
ume of materials sent to the site, fate of the materials at the
site and possible transhipments from the site to other sites.
• All insurance policies that may cover the cost of cleaning up the
site should be carefully reviewed. If there is possible coverage,
notice should be given to the insurance company as soon as
possible.
• All employees involved in shipments to the site (including plant
personnel) should be interviewed, and their observations
should be memorialized.
Armed with information from the above type of investigation,
the PRP will not only be in a good position to respond to the
CERCLA Section 104(e) letter, but also will be able to effective-
ly evaluate the extent to which it should participate on the PRP
Committee.
A PRP who sent small quantities of hazardous substances to
the site faces a dilemma. On the one hand, participation in a PRP
Committee is time-consuming. On the other hand, the problem of
joint and several liability makes at least some form of participa-
tion almost mandatory. Generally, a small quantity PRP will
want to minimize its presence at PRP meetings but maximize its
impact on PRP decision-making. This can be done best by per-
forming all investigations set forth above as early and thoroughly
as possible. With detailed information regarding its contribu-
tion to the site, the small quantity PRP is in an excellent position
to protect its interests among the entire PRP group. One added
complication for large companies contributing small amounts of
hazardous substances to a site may be the tendency of regulators
to look for "deep pockets" as sources of funds for site cleanups.
PRPs who sent larger quantities of wastes to the site, however,
will want to take a much more active role in the organization,
functions and strategies of the group. These PRPs typically will
spend the most time and resources in dealing with the site.
One of the most difficult jobs of the PRPs is to develop an
allocation or apportionment scheme for sharing costs of site
cleanup. It is at this juncture that most PRP groups have the
greatest problems. Antagonisms can be expected to arise between
LEGAL/ENFORCEMENT 19
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larger quantity and smaller quantity PRPs.
Another problem facing PRPs is the extent to which they
should participate in the Remedial Investigation and Feasibility
Study (RI/FS) regarding the site. Common wisdom suggests that
participation in the RI/FS increases the chances of keeping costs
down and improves opportunities for control over the scope of
work to be conducted on-site. However, there are disadvantages
to heavy participation in the RI/FS, especially if the PRP group
itself is to conduct the RI/FS. First, the U.S. EPA maintains
authority to supervise the work and to modify it in mid-course.
Through the so-called "On-Scene Coordinator," the U.S. EPA
may bring the conduct of a remedial investigation to a halt.
Second, the U.S. EPA often uses the mechanism of a consent
order under CERCLA Section 106 to allow PRPs to conduct the
RI/FS. Failure of the PRPs to comply with the terms of the con-
sent order may result in substantial penalties, including the possi-
bility of treble damages. In addition, Section 106 of CERCLA is
the Act's "imminent hazard" authority. Entering into a consent
order under Section 106 in order to conduct an RI/FS may give
the Agency jurisdiction which it otherwise might not have had.
Consequently, the decision regarding the extent to which the
PRPs should participate in or conduct the RI/FS must be made
on a case-by-case basis after carefully weighing all factors.
SALES OF HAZARDOUS SUBSTANCES
There has been considerable controversy regarding the extent to
which a generator may be held liable for the cleanup of a site if,
prior to disposal at the site, the generator had sold the material to
a third party who, in turn, disposed of it at the site either during
or after use. The key language of the Act appears in Section
107(a)(3), which provides that persons who arranged for disposal
or treatment at a site from which there is a release are liable for
cleanup costs. Arguably, Section 107(a)(3) should not include per-
sons who sold hazardous substances for use by others. Where the
vendees are the responsible parties under Section 107(a)(3), not
the vendors, who are merely the original generators of the
materials."
This position is supported by the specific language of Section
107(a)(3), which places liability on those who "arrange for dis-
posal" not on generators per se.
Courts addressing the issue have recognized the distinction
between "generators" and those who "arrange for disposal." In
an important recent case, one court stated that liability under
Section 107(a)(3) "is not endless" and is limited to the person
who decides how, where and by whom the waste is to be dis-
posed."
The issue of bona fide sales of hazardous substances takes on
even greater importance when viewed in the context of the en-
couragement of recycling and re-use of materials under RCRA."
A broad reading of CERCLA Section 107(a)(3) that would hold
generators liable for disposal of by-products sold 10 third parties
would act as a disincentive to recycling and reuse via sales, there-
by thwarting one of the purposes of RCRA,
In any event, generators who sell by-products or wastes should
ensure that their sales contracts expressly provide for indemnifi-
cation of any possible CERCLA liabilities regarding the ultimate
disposal of the materials being sold.
SETTLEMENT OFFERS
A settlement offer by PRPs to the government must carefully
evaluate the results of the RI/FS and must take into account the
U.S. EPA's CERCLA Settlement Policy and its RCRA/CERCLA
Policy regarding "how clean is clean."
The RCRA/CERCLA Policy" provides that the U.S. EPA will
ensure compliance with "applicable or relevant and appropriate"
federal environmental statutes in cleanups under CERCLA. State
standards may be used if appropriate for specific sites."
The term "applicable," as used in the RCRA/CERCLA Pol-
icy, refers to those federal requirements that legally apply. For
example, RCRA groundwater protection standards are applic-
able to the management of hazardous waste in groundwater.
Therefore, CERCLA groundwater cleanups will comply with
RCRA groundwater protection standards. The term "relevant
or appropriate" refers to those standards which are not legally
applicable but nonetheless provide useful indicators of appro-
priate cleanup levels and practices.
One of the important things to keep in mind about the RCRA/
CERCLA Policy is that it will come into focus at the Feasibility
Study stage and will drive the decision of the appropriate overall
cleanup remedy for the site. It is at that point that requirements
regarding which standards are "applicable" and which are "rele-
vant and appropriate" become crucial. This is an additional rea-
son for PRPs to participate in the RI/FS process.
The optimum time for making a settlement offer to the U.S.
EPA is as soon as possible after the cleanup remedy is deter-
mined. At that point, the PRPs must carefully evaluate the U.S.
EPA's Settlement Policy before making any settlement offer to
the Agency." The Settlement Policy addresses guidelines for
negotiation, criteria for evaluating settlement offers, targets for
litigation and other matters.
One of the most important aspects of the Settlement Policy is
the Settlement Criteria. Although an exhaustive discussion of the
Settlement Criteria is beyond the scope of this paper, a listing of
the criteria is instructive:
Volume of wastes contributed to the site by each PRP
Nature of the wastes contributed
Strength of evidence tracing the wastes at the site to the settling
parties
Ability of the settling parties to pay
Litigative risks in proceeding to trial
Public interest considerations
Precedential value
Value of obtaining a present sum certain
Equities and aggravating factors
Nature of the case that remains after settlement
Even a cursory review of the above ten criteria shows the
importance of retaining experienced environmental counsel to
conduct settlement negotiations with the U.S. EPA. Many of the
criteria are directly related to litigation risks and benefits, and
most involve the types of considerations discussed elsewhere in
this paper.
In short, the U.S. EPA's Settlement Policy should be used as a
guiding document by all who receive Section 104(e) letters. The
goal should be to obtain as much information as possible regard-
ing the site and the relative contributions of the various PRPs so
that a well-conceived settlement offer can be presented to the
Agency in accordance with the Settlement Policy.
CONCLUSIONS
Although CERCLA imposes stringent liabilities on companies,
there are a number of ways to maximize cleanup options and min-
imize liabilities. These options include being cautious in the pur-
chase of real property, taking an early, active part in the NPL list-
ing process, understanding the rights and obligations of PRPs,
ensuring that sales of by-products or used materials do not cause
unnecessary problems and taking advantage of the directions and
criteria set forth in the U.S. EPA's CERCLA Settlement Policy.
20 LEGAL/ENFORCEMENT
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REFERENCES
1. 42 U.S.C. Sections 9601-9657 (Supp V 1981).
2. The term "hazardous substance" is broadly defined in 42 U.S.C.
Section 9601 (14) to include a long list of substances regulated under
a variety of federal environmental statutes.
3. 42U.S.C. Section 9631.
4. 42 U.S.C. Section 9607(a). In addition to releases from facilities,
CERCLA also applies to releases from certain vessels. Id.
5. 42 U.S.C. Section 9607(c)(3).
6. 42 U.S.C. Sections 9607(a)(4)(c), 9607(0.
7. e.g., Colo. Rev. Stat. Section 29-22-101 to 106 (Supp. 1984); Fla.
Stat. Section 403.725(1) (1983); Ky. Rev. Stat. Section 224.876(12)-
(13) (Supp. 1984).
8. e.g., N.H. Rev. Stat. Ann. Section 147-B:1 to B:ll (Supp. 1983);
Okla. Stat. Till. 63, sections 1-2015 to 2021 (Supp 1984).
9. 111. Rev. Stat. Ch. lllVi, Section 1022.2 (1982); Mo. Rev. Stat.
Section 260.391(1) (Supp. 1982).
10. e.g., La. Rev. Stat. Ann. Sections 30:1147-1 to 11149.1 (West Supp.
1985); N.Y. Envtl. Conserv. Law Section 27-1301 to 27-1309 (McKin-
ney 1984 and Supp.).
11. Me. Rev. Stat. Ann. Till. 38 sections 1361-70 (1984).
12. New York v. South Shore Realty, 759 F. 2d 1032 (2nd Cir. 1985).
13. 42 U.S.C. Sections 6901-6987 (Supp. V 1981).
14. 42 U.S.C. Section 9604(e)(l)(B).
15. Id.
16. 40C.F.R. Part 2 (1985).
17. United States v. A&F Materials Co., 582 F. Supp. 842 (S.D. Ill
1984).
18. Id. at 845.
19. See Reference 13.
20. The RCRA/CERCLA Policy is set forth in an internal U.S. EPA
memorandum, dated Oct. 2, 1985, from J. Winston Porter to the
U.S. EPA Regional Administrators, titled "CERCLA Compliance
With Other Statutes."
21. CERCLA Section 104 provides that off-site remedial actions must
comply with the provisions of RCRA. Regarding compliance with
federal environmental standards in other contexts, however,
CERCLA is silent.
22. Interim Enforcement Policy for Private Party Settlements Under
CERCLA. Fed. Reg. SO, Feb. 5, 1985, 5034.
LEGAL/ENFORCEMENT 21
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U.S. EPA/State Relationship in CERCLA
Enforcement Actions at National Priorities List Sites
Anthony M. Diecidue
U.S. Environmental Protection Agency
CERCLA Enforcement Division
Washington, D.C.
Diana Baumwoll
Planning Research Corporation
McLean, Virginia
ABSTRACT
In this paper, the authors discuss the U.S. EPA's efforts to
more fully involve states in enforcement actions under CERCLA.
The authors also address how these efforts should lead to a more
coordinated and consistent approach during U.S. EPA and state
enforcement actions that seek private party cleanups. Specifical-
ly, the authors: (1) outline current thinking behind the need for
better coordination and cooperation between the U.S. EPA and
states in the CERCLA enforcement program; (2) review specific
efforts being implemented to enhance and improve the EPA/
state relationship; and (3) summarize what additional effect
CERCLA reauthorization will have on state participation in Fed-
eral enforcement actions.
INTRODUCTION
CERCLA, unlike other major environmental statutes such as
RCRA, does not impose any statutory requirements on states as
a precondition to being involved in or conducting CERCLA en-
forcement actions. As a result, the U.S. EPA and the states often
may proceed independently. The following considerations that
are absent from CERCLA further complicate the U.S. EPA/state
enforcement relationship.
• CERCLA does not require authorization of state enforcement
programs on the basis of minimum legal, technical and re-
source requirements that states must meet
• CERCLA does not require that state legal provisions and tech-
nical procedures used in their enforcement actions be consistent
with Federal standards
• CERCLA does not establish mechanisms for Federal involve-
ment in or oversight of state enforcement actions
• CERCLA does not require that states report the progress and
results of their enforcement actions
Due to the lack of specific requirements for participation in
the CERCLA enforcement program, states vary in their technical,
legal and administrative approaches and capabilities. This varia-
tion in capabilities may lead to situations where responsible party
settlement agreements or cleanups obtained by a state are incon-
sistent with or do not meet CERCLA requirements. In some
cases, it may even lead to problems in deleting a site from the
National Priorities List (NPL). Also, situations occur where Fed-
eral enforcement actions do not satisfy the desires of a state, such
as applying state standards, permitting and other requirements.
Furthermore, early identification and resolution of disputes be-
tween the U.S. EPA and a state is difficult since no formal mech-
anism exists for identifying and resolving problems.
In an effort to establish some framework for coordinating their
respective enforcement actions, the U.S. EPA and the Associa-
tion of State and Territorial Solid Waste Management Offic-
ials (ASTSWMO) signed a joint policy statement on Oct. 2,
1984.' The policy confirms that absence of a statutory structure
for an effective U.S. EPA/state relationship has presented prob-
lems in the past, and that issues will continue to arise. However,
this mechanism was created to allow the U.S. EPA and the states
to deal with those issues in a way that can minimize conflict, en-
hance respective enforcement efforts and improve the chances for
mutually acceptable private party settlement agreements and
cleanups.
MAJOR ISSUES AFFECTING THE
U.S. EPA/STATE RELATIONSHIP
Based on discussions between U.S. EPA and state representa-
tives, the major issues confronting the U.S. EPA/state relation-
ships were divided into three categories: Coordination; State En-
forcement Authorities and Procedures; and Resources.
Coordination
It is established that absence of a comprehensive policy on the
U.S. EPA/state relationship has left U.S. EPA Regional Offices
and States to determine the level and scope of their relationship
on an ad hoc basis. As a result, the level of coordination and co-
operation varies among U.S. EPA's Regional offices, as well as
among states within the same Region. Without the benefit of
guidance from the U.S. EPA to the states on specific issues,
differences in the policies and procedures used to conduct state
enforcement actions exist among states and between the states
and the U.S. EPA.
This lack of coordination and cooperation is compounded by
the absence of any formal approach to sharing information be-
tween the U.S. EPA and the states on the status of enforcement
actions. These problems also have led to occasional delays and
conflicts in administrative and judicial enforcement actions. If
differences between the U.S. EPA and a state are discovered at
all, they may occur late in the enforcement process and beyond
the point of meaningful Federal or state participation.
Slate Enforcement Authorities
and Procedures
Most states rely either on broad state environmental or gen-
22 LEGAL/ENFORCEMENT
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eral statutes, or on state hazardous waste legislation enacted prior
to CERCLA. State statutes often do not provide the full range
of authorities available to the Federal government under
CERCLA. Two examples of these authorities are:
• Under Section 106 of CERCLA, fines of up to $5,000 per day
can be applied against any responsible party who willfully
violates or fails or refuses to comply with an administrative
order issued under the section
• Under Section 107 of CERCLA, the U.S. EPA may seek treble
damages from any responsible party who fails without suffic-
ient cause to properly provide response actions under Sections
104 and 106 of the Act.
In the absence of equivalent authority, some states work in-
formally with responsible parties. This informal working rela-
tionship can lead to arrangements that are difficult to successfully
enforce. State negotiations with responsible parties sometimes are
conducted without a time limit. In this instance, negotiations
easily can become protracted. Thus, it is often difficult to assess
the likelihood of successful state negotiations or whether respon-
sible parties will conduct cleanups consistent with the National
Contingency Plan (NCP).
Resources
Funding for state hazardous waste enforcement programs
varies widely between states. An ASTSWMO survey conducted
in 1983 confirmed that less than adequate resources are generally
available at the state level.2 Specifically, the survey showed that:
• Anticipated increases in funding among the states still leaves
staffing short of what is minimally required
• Limited funding affects the states' ability to employ the neces-
sary disciplines required to conduct their enforcement pro-
grams
Without adequate funding, states have been limited in the num-
ber of enforcement actions taken and the level of oversight pro-
vided during responsible party response actions.
ACTIONS TAKEN TO IMPROVE THE
U.S. EPA/STATE RELATIONSHIP
Not all issues confronting the U.S. EPA and the states can be
resolved through the U.S. EPA/ASTSWMO joint policy. For ex-
ample, funding assistance for additional state program personnel
is beyond the scope of CERCLA to provide. Also, any inade-
quacies that may exist in state legal authorities is a matter for
states to resolve on an individual basis through their state legis-
latures. However, the U.S. EPA's Office of Waste Programs
Enforcement (OWPE) has begun developing specific guidance to
effectively implement many of the recommendations outlined in
the U.S. EPA/ASTSWMO joint policy.
Classifying NPL Sites as State-Led
Enforcement
CERCLA authorizes two basic approaches to dealing with a
hazardous substance release. The government (U.S. EPA or
state) may act using monies from the Hazardous Response Trust
Fund and subsequently attempt to recover costs from respon-
sible parties. The second approach is to use negotiations and ad-
ministrative or judicial enforcement actions to encourage or com-
pel responsible parties to finance and manage response actions.
However, current U.S. EPA interim guidance on classifying
sites as Fund-financed or enforcement response does not provide
for state involvement in determining which approach is most
appropriate. Although the U.S. EPA's regional offices should
consult with states in making enforcement classifications, the
lack of guidance for state involvement has caused inconsisten-
cies in this effort. Cases arise where a Fund-financed or Fed-
eral enforcement classification might more properly have been
classified as a state enforcement site based on information avail-
able or actions taken at the state level. In some cases, this lack
of guidance may even cause duplicate or opposing actions to
occur at a particular site.
The U.S. EPA/ASTSWMO joint policy helped to correct this
problem by establishing a procedure for consultation with states
to determine whether an enforcement site should be U.S. EPA-
or state-led, or "shared-led" where both the U.S. EPA and the
state jointly pursue enforcement actions at the site.3 In determin-
ing lead responsibility for enforcement sites, the U.S. EPA's
regional offices and states are to consider the following factors:
• Past site history, i.e., whether there has been a U.S. EPA or
state enforcement activity at the site
• Effectiveness of enforcement actions to date
• Strength of legal evidence to support the U.S. EPA or state
action
• Severity of problems at the site
• National significance of legal or technical issues presented by
the site
• Availability of U.S. EPA and state legal authorities and ade-
quate personnel and funding resources to enable effective
action
If, on the basis of these considerations, a site is classified as
state-led enforcement, the state must assure it will:
• Prepare, or have the responsible party prepare, a remedial in-
vestigation and feasibility study (RI/FS) and provide for public
comment, in accordance with applicable U.S. EPA guidance
• Conduct negotiations with responsible parties formally (e.g.,
culminating in the issuance of an enforceable order, decree or
other enforceable document) and, to the extent practicable,
within agreed time limits
• Provide for public comment on settlements, voluntary and
negotiated cleanups, and consent orders and decrees in accor-
dance with applicable U.S. EPA guidance
• Pursue and ensure implementation of a remedy that is consis-
tent with the NCP
• Keep the U.S. EPA informed of its activities, including con-
sulting with the U.S. EPA's Regional office when issues arise
that do not have clear-cut solutions
If a state in unable to provide the above assurances, the site
cannot be classified as a state-led enforcement site. However, the
regional office may consider sharing aspects of the response so
that state enforcement interests can be directly represented.
This approach to classifying state-led enforcement sites now is
being applied consistently across the U.S. EPA's Regional of-
fices. The most recent and beneficial use of the site classifica-
tion process has occurred with states in the U.S. EPA's Denver
Regional office. Until recently, only one site within the Region
had a state-led enforcement site classification. A major reason
was the difficulty in determining and agreeing whether state laws
and standards were adequate to successfully pursue enforcement
action consistent with CERCLA requirements. Using the site
classification approach outlined in the U.S. EPA/ASTSWMO
joint policy as the primary tool, the Denver office and their states
are now successfully coordinating and negotiating formal agree-
ments for sites within the Region. Several sites now are classi-
fied as state-led enforcement and more are anticipated within the
next year. Without the benefit of the classification criteria, the
Regional office and states would not have had any common
ground or understanding for determining the ability of states to
pursue enforcement actions at NPL sites.
LEGAL/ENFORCEMENT 23
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Upon CERCLA reauthorization, the U.S. EPA intends to re-
vise the interim draft guidance to properly include state involve-
ment in the site classification process and other areas requiring
state participation.
Funding State CERCLA Enforcement
Activities
The U.S. EPA's Office of General Counsel (OOC) recently
reconsidered an earlier view on funding of state enforcement
activities at NPL sites, reflected in a July 20, 1984 opinion. The
July 20, 1984 opinion limited assistance to identification of
potentially responsible parties (PRPs) and gathering of evidence,
RI/FS to support state enforcement actions, and oversight of
RI/FS and remedial designs (RD) conducted by PRPs. On Feb.
12, 1986, the original opinion was broadened to allow such activ-
ities as: oversight of PRP-conducted remedial actions (RA) and
operation and maintenance (O&M); negotiation and litigation to
encourage or compel PRPs to initiate response actions; and re-
porting to the public on PRP response actions. The rationale is
that these activities can be defined as a "response" under Sec-
tion 104(b) of CERCLA and, consequently, are eligible for
CERCLA funding." CERCLA reauthorization also will amend
Section 104(d), adding state enforcement to the list of activities
that can be funded through cooperative agreements and thereby
statutorily allowing what has already been established in the
OGC opinions.
Therefore, state CERCLA enforcement activities conducted at
NPL sites can be broken down into three major categories.
• State-led RI/FS to support state enforcement actions
• State-led PRP searches, issuance of notice letters, negotia-
tion, administrative action and litigation
• Oversight of RI/FS, RD, RA, and O&M conducted by PRPs
at state-led enforcement sites
In response to the U.S. EPA OGC opinions and reauthoriza-
tion, OWPE has prepared funding guidance for each category of
activities. The existing guidance on funding state-led RI/FS out-
lines the requirements for the first category of activities.' The
provisions states must agree to, tasks to be funded and level of
funding to be provided for an enforcement-related RI/FS are
the same as for any other RI/FS.
For the second category, an interim draft guidance currently is
being reviewed by U.S. EPA Headquarters management and
soon will be available to the U.S. EPA's regional offices and
states.' The intent of funding states for these activities is to suc-
cessfully secure the greatest number of private party cleanup ac-
tions possible. Funding these activities will enable states to devote
the time and resources necessary to achieve adequate settlements
and judgments. Since Federal funds may be provided, the guid-
ance will require states to follow the Agency's enforcement pol-
icies and procedures to the extent possible under state law. This
requirement is necessary to ensure that state-led enforcement
site cleanups:
• Are consistent with the NCP and applicable U.S. EPA guid-
ance
• Do not require or, if necessary, preclude future Federal en-
forcement action
• Enable the U.S. EPA to delete the site from the NPL
Cooperative agreement funding for PRP searches, issuance of
notice letters, negotiation, administrative action and litigation
will be provided only at NPL sites which have been classified as
state-led enforcement. Prior to accepting cooperative agreement
applications for review and award, the classification criteria out-
lined above will be applied to the site. Once the classification is
made, a state will have to follow the provisions and requirements
outlined in the negotiation and litigation funding guidance. The
guidance also outlines the tasks to be funded and levels of fund-
ing to be provided for these activities.
For the third category of activities, a final oversight funding
guidance document has been prepared merging two previous
drafts in which oversight of remedial planning (RI/FS and RD)
and remedial implementation (RA and O&M) were separately
addressed.' Funding for oversight will ensure that states devote
adequate time and resources toward analyzing and reviewing the
PRP's work. This includes funding for review of PRP work plans
and deliverable*, field-related oversight, monitoring and sampling
and community relations.
Under the final oversight funding guidance, if a state has suc-
cessfully negotiated an administrative order, consent decree or
other enforceable document, then the state has the lead for over-
sight of the PRP's work and is eligible for CERCLA funding.
The state may also, under certain circumstances, undertake vari-
ous, mutually agreed upon oversight activities at Federal-led
sites. These circumstances may include:
• CERCLA, Section 106 settlements with PRPs that are jointly
negotiated and signed by the U.S. EPA and the state
• State oversight that can result in a more effective and timely
PRP response
The final oversight funding guidance will be issued to the U.S.
EPA's Regional offices and states in the near future. The guid-
ance also outlines the provisions states must agree to, tasks to be
funded and level of funding to be provided for state oversight.
During the next year, award of cooperative agreements under
the oversight guidance and negotiation and litigation guidance
will occur on a pilot project basis. The U.S. EPA feels this step
is necessary since funding of these activities is a new venture for
the U.S. EPA and the states and close oversight initially will be
required to ensure consistent national implementation. The long-
term budgetary and administrative impacts of this new program
effort are only now being determined. There currently are over
ISO state-led enforcement site candidates for some type of fund-
ing. However, at least ten cooperative agreements are planned
during the next year. The U.S. EPA's regional offices already
have received and currently are reviewing several applications for
awards.
U.S. EPA/SUte Enforcement Agreements
Where states do not request funding assistance for their en-
forcement actions, CERCLA does not provide the U.S. EPA
specific authority to be informed of and involved in these actions.
In an attempt to bridge this information gap, the U.S. EPA/
ASTSWMO joint policy called for the development of U.S.
EPA/State Enforcement Agreements (ESEAs) to define their re-
spective roles and responsibilities during CERCLA enforcement
actions. As stated in the joint policy, the purpose of the agree-
ments is to ensure that the extent of the U.S. EPA and the state's
relationship at each site is fully thought out and documented to
prevent misunderstandings at a later time.
Few ESEAs have been prepared since the joint policy was is-
sued. This lack of agreements is partially due to the lack of spe-
cific guidance on developing such agreements and the absence of
adequate resources in the regions to develop and oversee their
implementation. However, a recent decision made by the Assis-
tant Administrator, Office of Solid Waste and Emergency Re-
sponse (OSWER) to tie future U.S. EPA regional office resource
requests for state oversight to the existence of formal agreements
(cooperative agreements or ESEAs) with states will influence
their development in the future. Additionally, provisions for state
involvement in Federal enforcement actions outlined in CERCLA
reauthorization also will contribute to developing a more formal
24 LEGAL/ENFORCEMENT
-------
relationship with states.
OWPE has conducted a survey of existing ESEAs. Informa-
tion collected from this survey will be used to develop guidance
on the content and structure of ESEAs prepared in the future.
This will ensure that certain program requirements and responsi-
bilities are consistently applied during CERCLA enforcement
actions covered under ESEAs. Pending issuance of detailed guid-
ance on the content of ESEAs, agreements drafted so far have
covered many different subject areas, such as:
• Coordinating the U.S. EPA and state activities, from early site
planning through enforcement action and site cleanup
• Avoiding duplication of effort between the U.S. EPA and the
state
• Preventing lengthy negotiations with responsible parties
• Ensuring that response actions taken at state-led enforcement
sites are consistent with the NCP and applicable U.S. EPA
guidance
• Providing for smooth transition if a change in site classifica-
tion is required
• Providing for conflict resolution between the U.S. EPA and
the state
• Allowing for review and comment of state and responsible
party documents
• Providing a basis for information exchange between the U.S.
EPA and the state
Since OWPE has not issued guidance on ESEAs, these exist-
ing agreements vary widely in scope and content. Essentially, two
types of agreements have emerged: (1) generic agreements ad-
dressing all enforcement sites classified as state-led and (2) site-
specific agreements usually addressing a single site (or contiguous
sites within a geographical area).
One of the first ESEAs, drafted by the U.S. EPA's New York
Regional office and the New York State Department of Environ-
mental Conservation (NYDEC), adopted a comprehensive
approach to create a program for all state-led enforcement sites.
Provisions of the U.S. EPA/NYDEC agreement tie together the
state's enforcement planning activities and the Agency's annual
planning process, known as the Superfund Comprehensive Ac-
complishments Plan. Yearly revisions to the ESEA are based on
this coordination of the state and the U.S. EPA's planning activ-
ities. The agreement also contains a CERCLA enforcement pro-
tocol, provisions for regular management meetings and conflict
resolution, and state reporting requirements.
In the South Bay area of San Francisco, several semiconductor
firms have contributed to a groundwater contamination prob-
lem involving several proposed NPL sites. These firms have
agreed to perform a voluntary cleanup. This cluster of sites, shar-
ing close geographic proximity, a considerable overlap of respon-
sible parties and enforcement authorities, is well suited to a con-
solidated enforcement approach. Confusion arose when the PRPs
and the U.S. EPA discovered that cleanup activities came under
the jurisdiction of two state agencies. To facilitate efficient and
effective enforcement action, both state agencies and the U.S.
EPA's San Francisco Regional office developed a site-specific
ESEA to clarify their respective authorities, roles and respon-
sibilities.
ESEAS also have been drafted to address legal, technical and
administrative details specific to a particular enforcement action.
Agreements can be made between the U.S. EPA and the state
concerning specific settlement provisions, reporting require-
ments, technical issues and community relations requirements.
Thus, ESEAs can be adapted to deal with special circumstances.
At the present time, ESEAs are not mandatory and are devel-
oped at the discretion of the U.S. EPA's regional office and the
state. However, because of the Assistant Administrator's decision
on regional resource requests for state oversight and new require-
ments outlined in CERCLA reauthorization, pending guidance
on ESEAs may require their use in the future.
Reporting and Exchange of Information
As states become more involved in CERCLA enforcement ac-
tions, the flow of information between the U.S. EPA and the
states will continue to increase. The Agency will need to ensure
that state enforcement actions at priority sites are conducted con-
sistent with U.S. EPA procedures and adequate to allow for dele-
tion from the NPL. The U.S. EPA also will need to determine,
in addition to the appropriateness of state enforcement efforts,
whether Federal review and participation are necessary. CERCLA
reauthorization also will increase the amount of information ex-
change required in order to have adequate state participation in
Federal enforcement actions. The sharing of information needs to
be reciprocal in our efforts to seek responsible party cleanups.
The U.S. EPA/ASTSWMO joint policy recognized that shar-
ing information between the U.S. EPA and the states is key to
developing a more effective relationship. The policy, therefore,
encouraged states to keep the U.S. EPA informed of their activ-
ities, including consulting with regional offices when issues arise
that do not have clear-cut solutions.
Until recently, the U.S. EPA had very little information de-
scribing the status of enforcement actions at state-led enforce-
ment sites. Specifically, a recent review of OWPE's Case Man-
agement System (CMS) showed that of the 157 sites listed as state-
led enforcement, only 44 have a negotiation activity listing (Re-
moval, RI/FS, RD/RA or other). Of the 44 sites, 21 were listed
as having initiated negotiations with PRPs to conduct the activity.
Of the 21 sites, only 7 had information on the type of negotia-
tion taking place (administrative order, judicial action, cost re-
covery, etc.).
In response to this problem, the Assistant Administrator,
Office of Solid Waste and Emergency Response issued a mem-
orandum on March 14, 1986, reiterating the principles of infor-
mation exchange set forth in the U.S. EPA/ASTSWMO joint
policy." The memorandum also encouraged U.S. EPA regional
offices to enhance the quality of information available on state-
led enforcement sites. As an initial step, OWPE conducted a sur-
vey and categorized each site by the type of enforcement action
taking place. The regional offices are now routinely updating this
information on a quarterly basis. In addition to this new regional
reporting requirement, the Agency is continuing to work with
ASTSWMO to develop additional state reporting requirements
and address the information needs of states at Federal-led en-
forcement sites.
EFFECTS OF CERCLA REAUTHORIZATION
ON THE U.S. EPA/STATE RELATIONSHIP
Thus far, the discussion has focused on the increased role of
states as they pursue enforcement actions at NPL sites. However,
CERCLA reauthorization will provide new, expanded opportun-
ities for state involvement in Federal enforcement actions as well.
As of this writing, specific language agreed upon by House
and Senate conferees has not become final. In general, the follow-
ing requirements will be added to the legislation.
• Specifically referencing "enforcement" under Section 104(d)
as a fundable activity through contracts and cooperative agree-
ments
• Applying state standards to on-site and off-site response ac-
tions carried out under Section 106 of CERCLA
• Developing regulations for state involvement in the CERCLA
enforcement process
LEGAL/ENFORCEMENT 25
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• Providing state concurrences for Section 106 enforcement ac-
tions and Federal facilities response actions
CERCLA reauthorization is consistent with and supports the
U.S. EPA's current efforts to fund states during their enforce-
ment actions at NPL sites. However, some revisions to the pend-
ing guidance documents will be required based on new or revised
requirements outlined in other sections of the Act.
Specific requirements for applying state standards to on-site
and off-site response actions under Section 106 will be required
upon CERCLA reauthorization. For on-site actions, the need to
attain applicable or relevant and appropriate requirements
(ARARs) will apply to any promulgated state requirement or
facility siting law that is more stringent than any Federal require-
ment and that has been identified to the U.S. EPA in a timely
manner. These requirements will apply unless they result in a
statewide ban on land disposal, except where certain factors out-
lined in CERCLA reauthorization are met. A remedial action that
protects human health and the environment, but does not meet
ARARs for on-site actions, can be selected if certain waivers also
outlined in CERCLA reauthorization exist. For off-site actions,
hazardous substances, pollutants or contaminants can be taken
only to facilities operating in compliance with RCRA or other
Federal laws where applicable.
CERCLA reauthorization also establishes a formal process for
state involvement in NPL site cleanups. The U.S. EPA must
promulgate regulations for substantial and meaningful involve-
ment in the initiation, development and selection of remedial ac-
tions. With regard to CERCLA enforcement sites, this will in-
clude participating in negotiations with PRPs, reviewing and
commenting on RI/FS, RD and RA and commenting on the selec-
tion of remedy.
State involvement requirements also will apply to enforcement
actions taken under Section 106 of CERCLA and actions at Fed-
eral facilities. For Section 106 actions, CERCLA reauthorization
provides opportunity for state concurrence and establishes a pro-
cess for state intervention before entry of a consent decree and
circumstances under which a remedial action would be required
to comply with ARARs. For Federal facilities, opportunity for
state concurrence also is provided as well as allowing states to
bring action in court to determine whether the action should con-
form to state requirements.
CONCLUSION
In conclusion, the sum total of these efforts to carve states a
larger role in taking their own enforcement actions and to pro-
vide a better avenue of involvement in Federal enforcement ac-
tions should lead to a more coordinated and successful CERCLA
enforcement program. As the Agency continues to implement
the U.S. EPA/ASTSWMO joint policy recommendations and
begins to formulate specific policy and guidance on the new statu-
tory requirements, the continued cooperation from associations
such as ASTSWMO and the National Association of Attorneys
General (NAAG) will be sought. So far, the cooperation of these
groups has added to the quality and acceptability of Agency de-
cisions on state participation and should continue to be valuable
in the future.
REFERENCES
1. Thomas, L.M., Lazarchik, "EPA/State Relationship in Enforce-
ment Actions for Sites on the National Priorities List," Oct. 2, 1984.
2. Ibid., J.
3. Ibid.,7-9.
4. DeHihns, L.A. Ill, "Authority to Use CERCLA to Provide Enforce-
ment Funding Assistance to States," JuK 20, 1984 and Feb. 12. 1986.
5. Office of Emergency and Remedial Response, "Stale Participation in
the Superfund Program," Feb. 1984.
6. Potter, J.W., "CERCLA Funding of State Enforcement Activities
at National Priorities List Sites," forthcoming.
7. Porter, J.W., "CERCLA Funding of Slate Oversight of Potentially
Responsible Parties," forthcoming.
8. Porter, J.W., "Reporting and Exchange of Information on State
Enforcement Actions at National Priorities List Sites," Mar. 14, 1986.
26 LEGAL/ENFORCEMENT
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The Effect of the National Contingency Plan
Revisions on Federal, State and Private
Superfund Cleanup Actions
John C. Hall
Wickwire, Gavin and Gibbs, P.C.
Washington, D.C.
ABSTRACT
On November 20, 1985, the U.S. EPA published a revised Na-
tional Contingency Plan (NCP). (See, Fed. Reg. 59, 479 et seq.)
The revised NCP has substantially altered the criteria for govern-
ment and private party action under CERCLA and has far
reaching effects on all parties involved in the CERCLA process.
Short-term actions known as removals are easier to justify and
will occur more frequently and the cleanup standards for longer
term, remedial actions have become more stringent and complex.
The revised NCP now provides community groups with formal
intervention into the decision-making process and provides a
framework for private parties to sue those responsible for haz-
ardous waste releases. As a result of these changes, the cost of
CERCLA actions is almost certain to increase as well as the
volume of lawsuits initiated by private parties.
INTRODUCTION
The National Oil and Hazardous Substances Contingency Plan
(NCP) outlines the operating procedures and response
mechanisms for the government's actions under CERCLA, other-
wise known as Superfund (42 U.S.C. §9601 etseq.). The existing
NCP was published in the Federal Register on July 16, 1982 at 40
CFR Part 300 (47 Fed. Reg. 31180-31243).
After two and one-half years of implementation, the U.S. EPA
has determined that substantial revision to the NCP could in-
crease its ability to effectuate enforcement actions, foster private
party settlements and streamline Fund-financed cleanups. In cer-
tain respects, the existing NCP restricted the authorities granted
to the U.S. EPA under CERCLA. Because many program con-
straints which were the outgrowth of litigation challenging the
NCP (EOF V. U.S. EPA, (No. 82-2234, D.C. Cir., February 1,
1984); State of New Jersey v. U.S. EPA, (No. 82-2238, D.C. Cir.,
February 1, 1984) (the EDF Consent Decree), proved unduly
restriction, the U.S. EPA decided to revise the NCP.
Pursuant to the EDF Consent Decree, the U.S. EPA agreed to
base cleanup levels on U.S. EPA-developed standards and
criteria, whenever applicable, institute a formal community rela-
tions program and determine the need to comply with other
federal, state and local laws.
The proposed NCP changes address many difficult issues fac-
ing the program and, individually, are very significant. However,
when viewed as a whole and when their interrelationships are fully
understood, they signal a revolutionary approach to the Super-
fund Program. This paper outlines the major NCP revisions and
evaluates cross-cutting impacts of these changes.
THE REMOVAL PROGRAM
Removal actions may be taken at any facility, whether or not it
is listed on the National Priorities List (NPL). Removal actions
are statutorily limited to $1 million or 6 months duration unless
an emergency condition continues to exist. Historically, removal
actions were considered emergency response measures to abate
life-threatening conditions posed by hazardous substance
releases. Typical removal situations were tank car derailments,
fires at storage facilities or serious ground water contamination.
The removal program was basically a continuation of the
U.S. EPA's oil spill program established under the Clean Water
Act. Consistent with its origin, the prior NCP substantially
restricted the circumstances permitting a removal action. The
removal criteria required a determination that "the initiation of
immediate removal action will prevent or mitigate immediate and
significant risk of harm to human life or health or to the environ-
ment...."
Under the proposed NCP, the ability to take removal actions
will be greatly expanded by reducing the threshold that triggers
such action. Removal actions now may be taken where "there is a
threat to public health, welfare or the environment. . ." (See 40
CFR §300.65(b)(l). The proposed NCP includes several factors
indicating a threat. Most factors require a determination of
whether there is an exposure to or release of a hazardous
substance. This avoids the need to quantify the magnitude of the
threat associated with the conditions. Essentially, a threat suffi-
cient to trigger removal action exists whenever a release or threat
of release of a hazardous substance may occur.
The proposed revisions also outline typical response actions for
typical removal situations. For example, capping of contaminated
soils or sludges is considered appropriate where needed to reduce
migration of hazardous substances into the soil, groundwater or
air. This section establishes a presumption that the U.S. EPA has
taken action "consistent with the NCP," which is a requirement
for cost recovery pursuant to CERCLA §107.
The U.S. EPA's primary reason for the proposed changes is to
reduce its burden in cost recovery actions. Properly demonstrat-
ing that an immediate and significant risk existed required an ex-
pert witness presentation of detailed technical analyses. U.S. EPA
personnel executing removal actions usually were not qualified
for this evaluation. The new factors that trigger removal action
involve determinations that can be made without such "health ex-
perts."
This NCP revision raises the issue of whether the U.S. EPA
may take a removal action whenever any release of a hazardous
substance occurs, or whether a minimum threshold threat to the
public or the environment must be crossed before the statute
authorizes the U.S. EPA to respond (as is the case with most
other environmental statutes). The U.S. EPA's proposal has seri-
ous implications because under CERCLA and the NCP anyone
may undertake a removal action if the criteria are met.
The U.S. EPA position is: If a release occurs, assume that a
LEGAL ENFORCEMENT 27
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threat exists and removal action is authorized. Arguably, the
U.S. EPA's position is inconsistent with several provisions of the
Act: the requirement to investigate the extent of threat first
(CERCLA §104[b]); allowance for federally permitted releases
(CERCLA §101(10]); notification of only releases exceeding re-
portable quantities (CERCLA §103); definition of removal which
includes actions necessary to protect public health (CERCLA
§101[23]); and the requirement that standards (i.e., thresholds) be
established for removal actions (CERCLA §105).
Although the U.S. EPA is likely to exercise its removal author-
ity only in response to serious threats, consistent with its current
approach, private parties need not exhibit such discretion. The
NCP proposal allows anyone to initiate removal actions at de
minimis releases which unfortunately could divert responsible
party resources from more substantial threats.
COMMUNITY RELATIONS PROGRAM
The proposed NCP formally institutes a Community Relations
(CR) program for removal actions that extend over 45 days,
remedial actions and enforcement actions. The CR program is
designed to provide the public with accurate information about
site conditions and give citizens the opportunity to comment on
the technical remedies proposed. Where applicable, formal CR
plans must be developed and approved prior to the initiation of
field activities. These plans will be implemented during the course
of the action, typically through workshops, press releases and
public hearings.
Responsible parties will be allowed to develop and implement
CR plans with U.S. EPA oversight. This condition provides the
responsible parties the opportunity to improve their community
image and present all the information necessary to assure the
public that adequate protection will be provided.
The CR program is the U.S. EPA's way of achieving "func-
tional equivalency" with the federal NEPA process. In other
U.S. EPA programs, such as Construction Grants under the
Clean Water Act or the RCRA permitting, public participation
has had a strong influence over pollution control decisions.
Because the CR program provides the public with a similar
mechanism to influence response decisions, it may result in
greater consideration of community concerns over acceptable
remedial alternatives and levels of cleanup.
REMEDIAL ACTION
Remedial actions are long-term, permanent remedies to
minimize or prevent hazardous substance releases. Unlike
removal actions, they are not limited in cost and may be taken
only after extensive analysis of site conditions. Fund-financed
remedial actions may be taken only at NPL sites.
As in the removal program, the U.S. EPA has proposed several
new factors that must be considered in developing remedial action
alternatives. The most significant revisions to the remedial pro-
gram address the "how clean is clean" issue and provide detailed
guidance on developing remedial action alternatives. The pro-
posed changes operate to restrict the U.S. EPA's discretion in
choosing the cost-effective alternative and provide a bias toward
more permanent remedies.
Of all the proposed changes to the remedial program, undoubt-
edly the most controversial is the U.S. EPA's attempt to define
the level of cleanup required at a particular site—the "how clean
is clean" issue. The proposed approach involves assessment of ex-
posures, determination of applicable or relevant (AOR) standards
and criteria and integration of the exposure analysis with the
AOR standard to insure that adequate/consistent public health
and environmental protection is achieved. If there are no AOR
standards, a risk analysis of existing and projected exposure levels
is required. Although the generic framework is logical, the pro-
posed NCP provides little guidance over the existing NCP on the
issue of "how clean is clean." A brief walk through the new maze
will illuminate some of the problems.
An exposure assessment, which is the first step in the process, de-
termines the degree and routes of exposure to the environment and
local population. It also assesses residual exposures from remedial
alternatives. However, one cannot evaluate the level of exposure or
associated risks until the point of exposure is determined.
Whether one assumes that the exposed population is living just
beyond the security fence of the waste site or one-half mile away
at the closest house makes a tremendous difference in the lifetime
exposure calculated. Drinking water contamination highlights this
issue. In most instances, drinking water contamination is lower at
the tap while portions of the aquifer may be much more con-
taminated. Should the U.S. EPA assume that in the future some-
one will drill a well into the contaminated area or only base
evaluations on the existing situation? Under RCRA, the point of
compliance is generally the boundary line of the facility.
However, this may be a very unrealistic point to evaluate a
lifetime exposure. One can probably expect the U.S. EPA and the
responsible parties to calculate exposure levels at several points,
and then argue over which is the "most reasonable" because the
NCP is silent on the issue.
After the exposure is calculated, it must be compared to some
public health or environmental standard to determine the
necessary level of cleanup. However, one must first determine if
there are any AOR standards. This is no small task. There are no
Superfund standards, per se, only standards developed under
other programs (air quality standards, water quality standards,
etc.). However, each program has different guidelines on the level
of protection and application of the standards. No standards have
been developed incorporating the multiple chemical, multiple
routes of exposure problem encountered at Superfund sites.
Therefore, each AOR standard must be reevalulated individually
to be useful for determining the appropriate remedial alternatives.
To provide further guidance on how to select AOR standards,
the U.S. EPA has published a draft memorandum entitled
"CERCLA Compliance With Other Environmental Statutes,"
that outlines the types of standards and criteria that normally may
be AOR. The draft policy lists virtually every ambient and
technology-based standard or criterion ever developed by the
U.S. EPA. The U.S. EPA's policy merely restates the obvious
and provides little additional guidance.
The U.S. EPA's broad interpretation of potential AOR stan-
dards and criteria goes far beyond the intention of the parties
entering into the EOF Consent Decree which spawned this re-
quirement. The intent of those parties was to use ambient stan-
dards such as air quality standards or water quality standards to
determine cleanup levels. However, the U.S. EPA has taken this
ambient standard requirement one step further by stating that
technology-based standards such as RCRA standards are pre-
sumed AOR. The obvious implication is that all Superfund sites
must meet RCRA standards to comply with the NCP. Mandating
blanket compliance with RCRA is an incredible waste of
resources, offers virtually no environmental benefit in many in-
stances and contradicts the basic statutory framework established
under CERCLA.
To analyze whether or not RCRA technology-based standards
should be applied, one must contrast the essence of CERCLA and
the reasons for the development of the RCRA standards.
CERCLA is a health-based statute directed at tailoring site-
specific remedies to address individual problems arising from past
disposal of hazardous substances. CERCLA contains no discern-
ible mandate to develop a uniform technology-based approach
that may or may not be relevant to a particular site. On the other
hand, RCRA is primarily a prospective regulatory program to
28 LEGAL/ENFORCEMENT
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control the hazardous waste disposal industry. For this reason,
uniform standards were desirable and required by law.
The basic statutory inconsistency with imposing RCRA stan-
dards at Superfund sites is that RCRA standards are required
regardless of their environmental or public health need or cost-
effectiveness in providing public health protection. Because
RCRA standards are non-site specific, their implementation at all
Superfund sites typically may result in non-cost-effective expen-
ditures which would preclude fund-financed cleanup under the
Act. (See CERCLA §104[C][4]).
Because of the limited number of ambient standards, few stan-
dards, other than RCRA standards, are likely to be AOR. Where
no AOR standards exist, a risk assessment is necessary to deter-
mine the appropriate remedy. Therefore, risk assessments are
likely to become the norm rather than the exception.
Under present U.S. EPA risk assessment policies, conservative
assumptions often are used to compensate for insufficient data.
High safety factors result from compounding these conservative
assumptions dictating the need for, at times, unnecessarily strin-
gent controls.
Realizing this, responsible parties should obtain as much data
as possible to accurately calculate the risks. Review of the U.S.
EPA risk assessment should reveal the critical data gaps that most
influence the treatment decision. It is prudent for parties to invest
funds to accurately assess risks where a $5 to $50 million dif-
ference in treatment requirements is at stake. Where "Star Wars"
was the novelty of the 70s, "Data Wars" will be the buzzword of
the 80s.
Under the proposed NCP, there is one critical point that should
be noted in the application of AOR standards. An exception to
this requirement is permitted for enforcement actions where there
is a strong public interest to expedite the cleanup and litigation
probably would not result in the desired remedy. One finds it
unusual that the U.S. EPA is providing an incentive for responsi-
ble parties to litigate the U.S. EPA's overly enthusiastic applica-
tion of questionable standards. The more rigorously the U.S.
EPA attempts to apply RCRA standards at Superfund sites, the
more likely the U.S. EPA is to invoke the litigation exception to
avoid the application of those standards because responsible par-
ties refuse to execute unreasonable cleanup orders. Excessive
costs will drive responsible parties to rely on the court's common
sense in reviewing application of RCRA standards. Hopefully,
the U.S. EPA will take a more prudent and technically defensible
position in AOR determinations to avoid this outcome.
Several other proposed changes are noteworthy. In reviewing
off-site disposal alternatives, the U.S. EPA now is required to in-
vestigate potential migration at the eventual RCRA disposal
facility. This helps to ensure that a new problem is not created in
remedying the existing one. Review of prior U.S. EPA response
actions suggests that, at times, wastes have been sent to disposal
facilities that are not likely to meet all RCRA operating re-
quirements and therefore, may close in the future. These future
Superfund sites may have the U.S. EPA as a responsible party for
cleaning up the residual hazardous waste.
Although intended as an additional check on RCRA facilities,
this requirement may have several unintended side effects. For in-
stance, community pressure to relocate waste could be offset by
this requirement. Investigation of potential migration also may
force the U.S. EPA to follow the Act's preference for on-site
management more closely. (See CERCLA §102[24]). To the ex-
tent that the U.S. EPA favors on-site containment, remedial
response costs should decrease substantially.
The ability of the responsible party to implement and maintain
a remedy until the threat is permanently abated will be considered
in selecting the appropriate enforcement remedy. If circumstances
warrant, the U.S. EPA will require a more capital intensive, per-
manent solution rather than a less expensive alternative which
depends upon future maintenance by the responsible party for its
effectiveness. This helps the U.S. EPA to avoid the possibility of
future bankruptcy or neglect by the responsible party that might
require the U.S. EPA to subsequently maintain the project. One
can expect responsible parties to vehemently oppose U.S. EPA
selection of capital intensive alternatives where less expensive
alternatives with long-term maintenance can be properly man-
aged. In such situations, the U.S. EPA may require a perfor-
mance bond from the responsible parties to guarantee proper
maintenance.
PRIVATE PARTY ACTIONS
CERCLA §107 allows any person (including responsible par-
ties) to respond to a hazardous substance release and bring a cost
recovery action against those responsible for the release.
Response costs are recoverable if incurred "consistent with the
National Contingency Plan." This provides a mechanism for per-
sons to address releases that the U.S. EPA or states may not ad-
dress due to other priorities and for responsible parties to share
the costs of compliance.
Over the past three years, courts have struggled with numerous
issues raised in private party actions under CERCLA. The courts
currently are split on several issues: (1) whether sites must be on
the NPL as a prerequisite to cost recovery; (2) whether prior
government approval of the cleanup plan is necessary; and (3)
whether responsible parties may initiate actions for contribution
under CERCLA §107.
To increase the ability of other parties (e.g., private parties or
responsible parties) to execute cleanup actions and obtain cost
recovery or apportionment from responsible parties, a new NCP
section entitled "Other Party Responses" addresses the above
issues. The section states:
"any person may undertake a response action to reduce
or eliminate a release or threat of release. Section 107
authorizes persons to recover response cost consistent
with this Plan from responsible parties."
The section specifies the NCP provisions one must follow to be
"consistent with the National Contingency Plan."
The U.S. EPA's ostensible intent is to enhance settlement
possibilities by establishing a framework for contribution actions
within the NCP. By clarifying the U.S. EPA's interpretation of
the right of contribution under CERCLA, uncertainty over the
ability of responsible parties to obtain contribution is reduced. If
contribution is possible, responsible parties are more likely to set-
tle. The success of this incentive will depend upon the cost of the
subsequent contribution litigation and the ability of responsible
parties to obtain the information the U.S. EPA possesses con-
cerning liability of other parties at the site. Promoting private par-
ty actions should increase the overall number of response actions
because responsible parties can more readily be sued by private
parties, possibly community groups, who wish to clean up sites
that are not U.S. EPA priorities.
The proposed NCP states that prior governmental approval of
private party response measures is not required unless the
response involves an administrative order or fund preauthoriza-
tion (i.e.', a request for the Fund to pay for cleanup costs).
Even with the proposed changes, a private party's ability to ob-
tain cost recovery for remedial actions will be difficult due to the
technical complexity of such actions. However, one can expect a
torrent of removal action suits because of the reduced burden of
proof necessary to justify removal action. As previously dis-
cussed, removal actions are justified if a "threat to public health,
welfare or the environment" exists which is demonstrated by the
existence of a physical condition on the site. Such conditions
might be rusting drums, contaminated soils on the surface or the
LEGAL/ENFORCEMENT 29
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ability to walk on the site and receive an exposure. A film clip of
the site conditions in addition to some minimal sampling probably
would suffice to support a cost recovery action.
Because the U.S. EPA has listed a series of removal actions
considered appropriate to address specific threats, it is easy for a
party to prove consistency with the NCP where a condition ex-
isted and the specific remedy listed by the U.S. EPA was ex-
ecuted. The only solace that a responsible party may have is that
his liability under the removal section generally will be limited to a
million dollars.
There is one substantial stumbling block to the initiation of
private party action. Prior to initiating action, the private party
must obtain any applicable federal, state and local permits. The
permit requirement again raises the RCRA issues previously dis-
cussed. As long as the action does not include management of the
hazardous waste, RCRA permit requirements should not be trig-
gered. Such actions as placing security fencing around the site, in-
stallation of dikes and berms to prevent runoff, or the placement
of a cap over the site, consistent with the U.S. EPA's interpreta-
tions, are not management of a hazardous waste. Where the
private party seeks to move the waste off-site or drain a lagoon
that contains hazardous waste, RCRA requirements must be met.
The issue that the private party must face is whether to incur the
potential liability that results from waste management or settle for
on-site containment.
Concerning releases from liability, the section states that "im-
plementation of response measures by responsible parties, certi-
fied organizations or other persons does not relieve those parties
from liability." The purpose of this statement is two-fold. First,
where a responsible party has executed a response action pursuant
to an enforcement order, the U.S. EPA maintains that a blanket
release from subsequent liability will not be given. Second, the
U.S. EPA was concerned that parties may take a partial cleanup
action that does not meet the U.S. EPA's expectations. Responsi-
ble parties should be aware that the U.S. EPA may subsequently
require additional response measures which the responsible par-
ties would be expected to fund.
Although the possibility of subsequent U.S. EPA action is
always present, the likelihood of such an occurrence is slim,
especially for non-NPL sites. Given the tremendous workload
that the U.S. EPA has in regulating and responding to releases at
NPL sites and other high threat removal sites, the U.S. EPA is
not likely to second guess private party cleanup actions where
good faith efforts have been made to prevent further hazardous
substance releases. Realizing this situation, it may be in the best
interest of responsible parties to execute their own cleanup ac-
tions, preferably with some U.S. EPA or state oversight, because
the likelihood of future governmental action is minimal.
The final point that deserves attention is the U.S. EPA's recog-
nition of private party fund preauthorization. Fund preauthori-
zation provides assurances that if a response action is taken con-
sistent with a plan of action approved by the U.S. EPA, Super-
fund monies will be available to reimburse that party for response
costs. This is particularly important in those instances where a
responsible party is only liable for a percentage of the cleanup
cost yet still wishes to conduct the response action to keep costs
down. In such cases, the U.S. EPA may contribute the balance to
execute a full response action.
Fund pre-authorization will be granted only for response ac-
tions at NPL sites, removal action and CERCLA §104(b) activi-
ties (i.e., site investigations). The critical point to note is that
almost any release can meet the new criteria established for
removals. Therefore, almost any release could be eligible for
Fund preauthorization and a guarantee that Superfund monies
will be available to offset costs incurred. To the degree that the
U.S. EPA has increased the exposure of responsible parties to pay
for removal costs, they also have exposed the Superfund.
It will be interesting to see how the U.S. EPA treats
preauthorization requests for removal actions. In many instances,
even where viable responsible parties may exist, one would expect
parties executing removal actions to prefer to obtain
preauthorization rather than litigate a cost recovery action. Sup-
posedly, the U.S. EPA will only grant preauthorization for
releases considered a priority to avoid diversion of Superfund
monies to lesser threats. In practice, this is likely to turn into a
"first come first serve" priority system because of the substantial
efforts that would be required to investigate every request for
preauthorization and to prioritize those requests.
CONCLUSIONS
The proposed changes in the NCP would greatly expand the
authority and powers of the U.S. EPA and other parties to ex-
ecute response actions and obtain cost recovery from those
responsible for the releases. One can expect private party actions
and suits against responsible parties for contribution to increase
substantially as a result of the proposed changes and the success
rate of those actions to increase markedly.
The net effect of the proposed changes to the removal program
is that more removal actions can be taken and costs can be
recovered more readily. Where typical removal actions are ex-
ecuted by the U.S. EPA or a private party to address a typical
condition, courts will be compelled to find them consistent with
the NCP and award cost recovery pursuant to CERCLA §107.
The new removal section greatly increases the potential liability of
responsible parties.
The development of more accurate and detailed public health
and environmental impacts information will now play a critical
role in choosing the appropriate extent of response. Although this
may slow the decision-making process, the net impact on produc-
ing quality alternatives should be a positive one. Unfortunately,
U.S. EPA's attempt to address the "how clean is clean" issue has
failed to resolve the most pressing issues. In addition, inflexible
application of RCRA standards that may have little or no
technical relevance for implementing a cost-effective remedy to
protect public health, welfare or the environment would
significantly hamper cleanup progress. One can only hope that a
reasonable approach will be taken in this regard.
Communities affected by hazardous waste sites and interested
parties concerned about the level of control that the U.S. EPA
has proposed for a Superfund site have received several new tools
to control and accelerate the process. The Community Relations
Program offers the opportunity for direct involvement in the
selection of response alternatives, and the preauthorization sec-
tion helps communities take direct action.
Expansion of program flexibility increases the possibility that
the U.S. EPA and other parties may take arbitrary actions. To
that extent, the program and responsible parties may suffer unless
increased supervision is instituted. If the necessary supervision is
not provided by the U.S. EPA, undoubtedly it will fall to the
courts. If this occurs, program flexibility achieved through rule-
making will be narrowed to prevent arbitrary results. Only time
will tell.
30 LEGAL/ENFORCEMENT
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The Community Relations Benefits of
Resolving Private Property Legal Issues
Raymond C. Givens
Givens and Michaud
Coeur d'Alene, Idaho
Ian von Lindern, Ph.D.
TerraGraphics EEIS
Moscow, Idaho
ABSTRACT
The Bunker Hill Superfund site in northern Idaho is one of the
largest and most complex sites in the country. Much of the con-
taminated property within the site is private residential or com-
mercial property not owned by the Potential Responsible Party.
Cleanup of private property presents unique legal and com-
munity relations problems. Sharing authority with local interests
can be used successfully to prevent disgruntled local interests
from using politics or lawsuits to seize control from the project
managers. Fast-track, an interim removal cleanup program at the
site, is an example of how authority can be effectively shared and
legal and community relations problems can be solved in a
unique and successful way.
A local private attorney was retained to address the concerns
of the property owners whose property was to be cleaned up in
Fast-track. This approach enhanced community relations,
avoided potential legal difficulties and helped complete the pro-
ject on schedule.
INTRODUCTION
Many CERCLA actions involve cleanups in small company
towns. Special community relations and legal problems develop
when these cleanups are of private residential or commercial
property not owned by the potentially responsible party (PRP).
The community often sides with the PRP, being more concerned
with jobs than with health. Entering such a community to clean
it up can be as dangerous for the Superfund project team as enter-
ing the cage of an ailing grizzly bear to doctor it. The bear is prob-
ably more likely to maul the doctor than to accept the medica-
tion.
The Bunker Hill site project team recognized the need for an
effective community relations program. Project authority was
shared with local interest, and a local private attorney was re-
tained to deal with legal issues and concerns raised by private
property owners in the cleanup of their property. This paper
analyzes the success of that approach.
In the paper, the authors first discuss the background of the
Bunker Hill site. Next, the authors discuss the strategy developed
by the project team (project managers and contractors) to address
the site. The paper focuses on one aspect of that strategy—the
community relations program which retained a local private
attorney to address private property legal concerns raised by the
owners of the property to be cleaned up.
BACKGROUND
The Bunker Hill site represents one of the largest and most
complex projects in the country. It is an NPL site. It was also the
focus of a Natural Resources damage suit instituted by the State
of Idaho. Significant public health damage has been associated
with past smelter operations at the Bunker Hill site. This area
was long the center of one of the world's largest lead, zinc and
silver mining and smelting industries. The NPL site contains four
incorporated cities and about 5,000 people. The smelter complex
encompasses nearly 500 acres including a primary lead smelter,
an electrolytic zinc plant, an ammonium phosphate fertilizer
plant, a mine and mill operation, nearly 200 acres of impounded
tailings and numerous ancillary facilities. The lead/zinc smelter
closed in 1981.
Several important environmental features are found outside the
smelter complex but within the Bunker Hill NPL site boundaries.
A large area of the river flood plain historically served as an im-
poundment area for mine waste discharges. Significant rework-
ing of these tailings by both man and river has left deep beds of
unconfined contaminants. Seepage from two large confined tail-
ings impoundments has severely contaminated the groundwater.
Soils throughout the site have been badly abused. Forest fires and
indiscriminate timber harvesting early in this century denuded
most of the hillsides in the area. Sulfur-oxides emissions in the
following decades pre-empted regrowth. Subsequent erosion has
resulted in high soil acidity and the loss of topsoil, texture and
water holding capacity. Several thousand acres are almost barren
as a result. Local soils are toxic and a risk to public health as a
result of waste discharges, periodic floodings and years of smelter
operations depositing high concentrations of heavy metals. In the
majority of residential soils in three of the four cities within the
NPL site, lead contamination levels exceed the CDC warning level
of 500-1000 ppm lead. Cadmium, arsenic, mercury and other
metals routinely are found above action levels suggested at other
NPL sites.
The Bunker Hill area came to national attention in the mid-
1970s when an epidemic of childhood lead poisoning was discov-
ered following several months of smelter operations with severely
damaged pollution control equipment. All of the children living
within 1 mile of the smelting complex and the majority of those
children living within the NPL site boundaries had excess blood
lead absorption according to Center for Disease Control (CDC)
criteria. More than 40 children had clinical lead poisoning and
were treated as medical emergencies.
The state promulgated pollution control criteria, and a lead
health program was established. These steps substantially reduced
smelter emissions, and a corresponding decline in children's
blood lead levels was noted. The smelter closure in 1981 resulted
in an immediate decrease in air lead concentrations to near back-
ground levels. Blood lead levels, however, remained above CDC
criteria. Two years after the smelter closed, 25% of the children
living within 1 mile of the complex continued to exhibit high
blood lead levels.
LEGAL/ENFORCEMENT 31
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The major suspected sources of this lead contamination were
identified as contaminated residential soils and fugitive dusts
emanating from roadsides and barren soils. Among the chief rea-
sons for the U.S. EPA and state decision to proceed with RI/FS
activities at the Bunker Hill site were the demonstrated health
risks associated with the excess absorption in children and the
severe contamination levels noted in local soils.
PROJECT STRATEGY
It is always difficult for a bureaucracy to decide who has a legit-
imate interest in project decision-making. Yet this project design
is often one of the most crucial decisions in a project. Who is
affected by a particular CERCLA project is, to a great extent,
site-specific. The affected group depends on the magnitude of the
release; the media involved; the degree of off-site penetration;
the characteristics of the community, properties and resources
affected; and the role of the PRPs in the local economy.
Local control allows those most affected to have the greatest
say. But locals are often the most ill-informed, most prejudiced
and most vulnerable to economic and social pressures from polit-
ically powerful PRPs. Including such groups in the decision-
making process involves walking a fine line between facilitat-
ing a meaningful local program and losing control of the project.
Unfortunately, there is no magic formula for resolving this
dilemma.
One of the most effective methods of maintaining control of
the project is a continuing education process. The lead agencies
must educate and re-educate state and local interest groups. In
turn, those agencies must allow themselves to be educated to the
needs of local advocates. Each must respect the other's concerns
as being equally relevant and important to the resolution of pro-
ject issues.
Sharing the decision-making power with local individuals can
be most difficult for traditional program managers, but if prop-
erly handled, it can help keep project managers from losing con-
trol of their projects to the courts or the political arena.
Both the U.S. EPA and the state recognized that the Bunker
Hill site was among the nation's most complex with respect to
size, number of persons, types of properties affected and degree
of off-site contamination.
An innovative and well thought-out project strategy was re-
quired. Negotiations between the state and the U.S. EPA at the
Bunker Hill site began with the state in an advocacy role for local
interests. Understanding the ultimate project strategy requires
some knowledge of local and state attitudes toward the problem.
The state and county health officials had administered a lead
health program for over 10 years. The area was suffering desper-
ate social and economic problems associated with the loss of more
than 3,000 jobs when the smelter closed. Although the degree of
blood lead absorption exhibited by children in 1983 was among
the highest in the country, these levels were the lowest they had
been in over a decade. Community attention was focused more
toward problems associated with the 40% unemployment rate
than with decreasing blood lead levels. However, it was clear that
the years of smelting and mining operations had left a legacy of
residual contamination that represented a continuing threat to
public health. This was bound to hinder future economic rede-
velopment.
State and community leaders recognized that a cleanup was
essential to both public health and new economic development.
However, there was a lingering resentment of the federal govern-
ment. Environmental programs were blamed for the smelter clos-
ure and the resulting unemployment. The prognosis for a local or
state endorsement of a federal environmental project in the area
was grim.
Negotiations between the state and the U.S. EPA resulted in a
strategy that provided for joint administration of the project in a
manner that could both meet program needs and provide for a
maximum level of local involvement. The strategy called for state
and local control in certain areas of the project. Four principal
areas of investigation and remedial action were reserved for the
state. Those were: (I) public health protection, (2) community
relations, (3) socioeconomic impact evaluations and (4) remedial
activities associated with soils contamination on public and pri-
vate citizens' properties.
Total removal of the several thousand acres of contaminated
community soils was not feasible. It was likely that the ultimate
remedy would involve some combination of removal and lim-
ited institutional controls restricting access to or uses of certain
properties. Developing such land use restrictions would require
the cooperation of local governments, because, in Idaho, land
use restrictions are the province of local government. Before
local officials could be expected to adopt necessary land use ordi-
nances, they would need to understand the legal, social and eco-
nomic consequences. They also would need the support of their
citizens.
The U.S. EPA and the state both realized that the develop-
ment of such institutional programs in a hostile community would
be a nearly impossible undertaking. An innovative three-pronged
approach was chosen. The plan was to: (1) establish an aggressive
public health intervention program, (2) create a local task force to
monitor project efforts and (3) clean up the areas of potential
highest exposure quickly (Fast-track).
Since the entire project would take several years to complete,
the public health intervention program was necessary to meet the
on-going blood lead absorption problem among area preschool-
ers. The first state action undertaken was an aggressive inter-
vention program administered at the county level. Every home in
the area was visited at least once a year by a nursing team. Chil-
dren's lead absorption levels were monitored. If excess levels were
found, children were addressed individually from both nursing
and home environment perspectives. In 2 years, this program has
successfully reduced excess absorption in the area to less than 2^.
Creation of a task force of local citizens was the second prong
of the plan. This group was appointed by the local county com-
missioners. The task force monitored project efforts, partici-
pated in project decisions and acted as community advocates.
Two-day meetings were held at the site each month. Complete
project summaries were presented to the task force in an evening
public forum. The forum included representatives from several
area citizen, business and service groups. The task force was in-
volved in both the selection of the sites to be cleaned up in Fast-
track and the selection of the appropriate remedial action for
each site. The project managers and contractors provided the
technical information. The task force provided the practical in-
formation of what cleanup approach would be most compatible
with community use. The result was a constructive sharing of
information. Appropriate cleanup solutions (remedial actions)
were chosen which had broad based community support.
The third prong of the plan was to clean up some areas very
quickly. Several public access areas such as parks, playgrounds
and road shoulders were severely contaminated. They offered un-
due exposure to children. The interim removal program was used
to clean up these properties quickly under a plan called Fast-
track.
Fast-track afforded the project the opportunity to actively in-
volve the task force and local government officials in the decision-
making process. Many of the lessons learned in Fast-track will be
of great value in the ultimate clean-up at the Bunker Hill site.
These lessons also may be of value in other Superfund projects
32 LEGAL/ENFORCEMENT
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where the property to be cleaned up does not belong to the PRP.
The remainder of this paper focuses on Fast-track's handling of
legal property issues and community relations as they pertain to
those legal issues.
FAST-TRACK
There are many aspects of Fast-track which could be discussed.
However, the focus of this paper is on how the legal issues were
handled as part of the community relations program.
As the construction date for Fast-track approached, the prop-
erty owners (mostly local governmental entities) began to pose
numerous questions about the proposed cleanup. Many of the
questions were of a legal nature and concerned the property to
be cleaned up. The projects managers and contractors viewed the
legal questions as legitimate concerns which, if left unanswered,
could cause community relations problems and jeopardize the
project. It was obvious that the property owners could not af-
ford to hire legal counsel to address the matters. The situation
was complicated by the fact that two of the property owners were
represented by the same legal firm which represented the PRP.
The solution adopted was to involve a local attorney through
the state contractor. This attorney met with property owners and
listened to their concerns and questions. These concerns dealt
with knowing exactly what property was to be cleaned up, how
the contaminated soil was to be disposed of, and a score of liabil-
ity issues such as liability for refusing to allow the cleanup, liabil-
ity for an inadequate cleanup, liability for maintenance of a par-
tial cleanup and liability for participation as a subcontractor in
the cleanup. There were also questions concerning compensation
of the property owner by the U.S. EPA for any inconvenience
and damages suffered by the property owner during the cleanup.
After meeting with the property owners, the attorney met with
the project team to see what could be worked out. A report was
prepared which listed the various concerns of the property own-
ers and provided an analysis and recommendations to meet the
expressed concerns.
Several unexpected bonuses resulted from this "before-the-
fact" legal involvement concerning actual property ownership.
To make sure exactly who owned what property, the attorney
recommended obtaining legal descriptions and title searches for
all parcels. The proposed disposal site and some of the property
to be cleaned up were owned by different parties than originally
thought. This problem was determined early enough to find a new
disposal site and to obtain consents from the proper parties. Rec-
tifying this situation before cleanup prevented massive legal com-
plications which could have arisen later.
In the liability area, the public entities were informed that there
were some restrictions and potential liability if they acted as
subcontractors, but they could do it under state law. They also
were informed that they might have to pay Davis Bacon wages
(despite the wording in 42 USC 9604(g)). However, the U.S. EPA
later ruled that prevailing wages did not have to be paid. Property
owners were advised of their potential liability for managing tox-
ics left in place by the cleanup and who was liable for what if
additional cleanup was necessary on the same property. Property
owners also were informed of the U.S. EPA's options if the prop-
erty owners refused to consent to the cleanup.
One issue which should be discussed in some detail dealt with
compensation of the property owned by the U.S. EPA. The prop-
erty owners felt they were entitled to some compensation for
allowing the U.S. EPA and the state to come on to their property
and alter it in some way.
Cleaning up non-PRP property poses unique legal issues. The
United States Constitution allows the government to use or take
private property, but the property owner is entitled to compensa-
tion for that taking. This process can be done by consent or
through a condemnation proceeding. Government road building
on private property would be an example of taking private prop-
erty. There are other situations, however, where government can
effect the use of private property without compensation. Zoning
would be an example. Environmental regulation of property own-
ers who are using their property in a way that is hazardous to the
general public would be another example.
The property owner whose property has been dangerously con-
taminated by the act of another falls somewhere in between the
road building and environmental regulation examples. His prop-
erty in its present condition is a threat to the general public, but
neither the property owner nor his predecessors in interest are in
any way responsible for that threat. If the government determines
that the property must be cleaned up to protect the public good, is
this a taking requiring condemnation and compensation as in the
road analogy, or is it more similar to zoning or environmental
regulation where no compensation is required?
In this case, the property owners were not being greedy in ask-
ing about compensation. Instead, they were looking for a way to
satisfy the 10% state match of the larger Superfund cleanup to
come later. Idaho's Legislature had not established a method of
raising the 10% state matching monies for Superfund. Given the
state of Idaho's depressed economy and the legislative influence
of some potential PRPs, local officials (the property owners)
feared that the state might not be able to come up with the 10%
match. The property owners wondered if they could assign their
right to compensate from the U.S. EPA to the state who could in
turn pledge it to the U.S. EPA as part of the state's 10% match.
When cost recovery eventually was accomplished, the funds
would revert to the property owners from the PRP.
Research disclosed no specific prohibition of this innovative
approach. The U.S. EPA was intrigued but was reluctant to make
any commitments within the tight timeframe of Fast-track. The
result was to include a provision in the consent forms which re-
served the issue of compensation for Fast-track until the larger
cleanup was to take place. This is an excellent example of how a
potentially thorny private property issue can be sidestepped for
the time being and may eventually be turned to the benefit of the
project.
This early legal involvement also provided the property own-
ers with an analysis of the effect a parallel State Natural Re-
sources Superfund suit would have on Fast-track. The inter-rela-
tionship of these two Superfund programs is a complex and fas-
cinating issue, but it is beyond the scope of this paper. It is recom-
mended that if faced with such overlapping suits, one proceed
very carefully.
Involving a local, private attorney in Fast-track was very suc-
cessful for a number of reasons. It was a clear statement to the
community that the project team was willing to go to considerable
lengths to address community concerns. All of the property own-
ers signed written consents to have their property cleaned up
under the plans outlined by the project team. Minor legal prob-
lems were identified and addressed so that the project could pro-
ceed on schedule. Legal questions which could have grown into
lawsuits were dealt with to allow the project to proceed. Most
important, involvement of the local attorney to negotiate with the
U.S. EPA before minor issues became major problems helped the
project managers keep control of the project.
CONCLUSION
Some large Superfund projects involve cleaning up private resi-
dential or commercial property not owned by the PRP. This
cleanup of private property presents unique community relations
and legal issues which are often entwined. Sharing authority with
LEGAL/ENFORCEMENT 33
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local interests and an effective community relations program
which includes addressing local legal concerns can reduce the pos-
sibility that disgruntled local interests will use politics or the
courts to take control of the project out of the hands of the pro-
ject officers.
At the Bunker Hill site, local private counsel was hired to ad-
dress legal concerns of the property owners as part of the pro-
ject's community relations program. This approach, unique to
Superfund, was very successful. It built trust in the community
by showing that the project team was serious about addressing
community concerns. It identified potential legal trouble spots
which could be resolved before they became lawsuits or stumbling
blocks which delayed the project. It provided the benefit of a dif-
ferent legal perspective—just as a private construction company
can do some road jobs better than a government crew, so too,
are there places where a private attorney is preferable to a govern-
ment attorney.
The project team deserves considerable credit for innovatively
involving local legal counsel at an early stage of the proceeding.
By integrating this legal component into their community rela-
tions program, the project team was able to complete this pro-
ject on time without having to contend with lawsuits or political
pressure.
Private property legal issues always will be matters of great
community concern in any Superfund project cleaning up resi-
dential or commercial property not owned by the PRP. If the
Superfund projects' managers recognize the importance of shar-
ing authority with local interests and addressing private property
legal concerns through a good community relations effort, man-
agers can enhance community support for the clean-up, reduce
present and future legal problems and stand a much better chance
of completing their projects on schedule without political or
judicial interference.
34 LEGAL/ENFORCEMENT
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Remedial Planning Contracts
Nancy M. Willis
U.S. Environmental Protection Agency
Remedial Action Contracts Branch
Washington, D.C.
NEED
The U.S. EPA has identified 888 uncontrolled hazardous waste
sites as being a high priority for cleanup. These sites are either on
or proposed for the National Priorities List. Under the Superfund
law, these sites may be cleaned up by the states with Superfund
dollars under a cooperative agreement with U.S. EPA, or U.S.
EPA may take responsibility for the remedial response. The agen-
cy has contracted with engineering firms to conduct the studies
leading to selection of a remedy for these sites when the U.S. EPA
has the lead for the remedy.
STRATEGY
The current remedial planning contracts were designed to:
• Provide engineering services to conduct remedial investiga-
tions, feasibility studies and other technical studies for federal-
led remedial sites
• Provide this support in a manner flexible enough to accom-
modate fluctuating workloads
EXISTING CONTRACTS
U.S. EPA has three large remedial planning contracts:
• REMII
Prime
Period of
Performance
Area of
National
- Camp, Dresser and McKee
-June 1984 - June 1988
Responsibility
REM 111
Prime
Period of
Performance
Area of
Responsibility
REM IV
Prime
Period of
Performance
Area of
Responsibility
- EBASCO
November 1985 - October 1990
Region I - Revion IV
- CH2M Hill
-November 1985 - October 1990
- Region V Region X
STATEMENT OF WORK
The scope of these contracts is written broadly to include all of
the services needed to support the remedial program. Major areas
covered are:
• Remedial Investigations
• Feasibility Studies
• Design of Remedial Actions
• Implementation of Small Remedial Actions
• Oversight and Support of Remedial Response Actions Con-
ducted by Other Parties
• Enforcement Support
• Community Relations
• Quality Assurance
• Data Management
• Laboratory Support
• Technical Support
• RCRA Support
STRUCTURE OF THE CONTRACTS
All of the remedial planning contracts have three major com-
ponents:
• Program management hours
• Level of effort hours
• Subcontract pool
PROCUREMENT
These contracts were procured using a Brooks Act procure-
ment; the firms competing were evaluated and the most technically
qualified firm selected. The factors considered in selection in-
cluded:
• Demonstrated corporate and individual experience in perform-
ing remedial planning activities
• Capacity to perform in a timely way
• Experience in large, multi-discipline, multi-task order contracts
• Adequacy of the management plan for supporting the contract
• Quality of the response to management and technical problems
The selection processes resulted in cost reimbursement plus
award fee contracts.
FUTURE
U.S. EPA SUPPORT CONTRACTS 35
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The Field Investigation Team Contracts-
Scope and Functions
Scott Fredericks
U.S. Environmental Protection Agency
Washington, D.C.
INTRODUCTION
The purpose of the Field Investigation Team (FIT) contract(s)
is to provide technical support to the U.S. EPA to perform pre-
remedial investigative activities at hazardous waste disposal sites.
The U.S. EPA has relied on FIT contractor resources since 1980.
The existing FIT contracts are a part of the Zone (I & II) REM/
FIT contracts which were awarded on Oct. 1, 1982, and will ex-
pire on Sept. 30, 1986.
The FIT contracts constitute the primary capability of the Fed-
eral government for assessing, inspecting and ranking hazardous
waste sites. Specifically, the FIT contracts:
• Establish priorities for remedial action through Hazard Rank-
ing System (MRS) scoring and National Priorities List (NPL)
support
• Perform preliminary assessments (PAs) and site inspections
(Sis) to determine the nature of the problem at sites on the
CERCLA inventory
• Support enforcement case development
• Support special studies (e.g., dioxin, RI support)
• Support state PA/SI program (i.e., training) and
• Give general technical assistance
DESCRIPTION OF WORK FUNCTIONS
Preliminary Assessment
A PA is the first step taken after the U.S. EPA or a state dis-
covers a site. It involves reviewing existing information and
assessing current site conditions to determine if a potential threat
to the public or the environment exists. A PA may, but often does
not, involve a site visit. Sampling rarely is performed. The need
for a site inspection (SI) is based on the results of the PA.
Site Inspection
The purpose of a site inspection (SI) is to gather additional
data sufficient to rank the site using the HRS and to aid in mak-
ing judgments on what further actions are required at the site.
Historically, an SI involves a visual inspection of a site and usu-
ally includes limited sample collection.
A current initiative is underway to expand the scope of an SI
to provide better support to the development of the Remedial
Investigation (RI) work plan and scope. This expanded SI (ESI)
would also provide better support for the HRS, NPL and re-
lated program needs.
Enforcement Support
Enforcement support embraces a wide variety of technical
activities whose purpose is to support enforcement case develop-
ment and litigation, perform oversight or monitoring of respon-
sible party actions and generally augment the TES contract re-
sources by performing technical field activities. While RIs are
within the scope of work for the next FIT contract(s), it is not
anticipated that this will be a routine function.
Quality Assurance Support
Quality Assurance (QA) support is related primarily to the re-
view of Contract Laboratory Program (CLP) data for samples
taken by FIT during field activities. FIT currently provides back-
up for U.S. EPA Regional staff responsible for this activity be-
cause of the heavy workload. Certain QA functions also are asso-
ciated with routine technical activities.
Hazard Ranking Scoring
The application of the Hazard Ranking Scoring (HRS) is used
to determine a site's potential for inclusion on the NPL. This
determination includes background documentation and support
through QA/QC.
Special Studies
Special studies include unusual investigations often involving
"unconventional" sites, such as areas affected by Dioxin or pes-
ticide contamination, underground storage tanks, potential
RCRA Subtitle C facilities or small quantity generating facilities.
Involvement in these areas has been on a case by case basis,
following upper management decisions. Many of these areas may
be excluded in the near future, depending upon specific provis-
ions of CERCLA reauthorization legislation and EPA policy.
Special studies also include efforts such as: discovery projects,
NPL deletions and other various types of site investigations.
Training
Training includes basic and refresher training of FIT person-
nel in health and safety, site inspections, sample handling, HRS,
etc., as well as training support for U.S. EPA, state and other
contractor personnel.
Equipment Calibration and Maintenance
The area includes the necessary maintenance of the field equip-
ment and the calibration and standardization of the hand-held
analytical instruments used in gas chromatographic screening of
samples.
General Technical Assistance
General technical assistance includes literature searches, re-
views of other party reports and data, support in development of
national guidance or standard operating policies, preparation of
information for public information and similar support functions
which do not fall into investigative activities listed earlier.
Program Management
Program management involves the administrative and mana-
gerial functions necessary to operate the contract. This includes
FIT Regional managers and the Zone Program Management
Office (ZPMO). The ZPMO staff has managers for the follow-
36 U.S. EPA SUPPORT CONTRACTS
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ing operations: QA, subcontracts, technical operations, manage-
ment information systems and reports and the overall Program
Manager.
Subcontract Support
A pool of money is specifically set aside and tracked to finance
subcontractor services. These support services are not provided
through either the dedicated ZPMO or Regional FIT Office
staffs. Services include: well drilling, geophysical investigation
support, special consultants and analytical support.
SIZE AND COSTS OF EXISTING CONTRACTS
The current FIT portions of the REM/FIT Zone contracts
cost approximately $35M for FY 85. The total estimated costs
for the period of October 1982-Sept. 1986 are:
$(Million)
Zone I—56M
Zone II—59M
Level of Effort
171
194
115M
365
SCOPE AND SIZE OF PROPOSED CONTRACTS
These will be 5-yr contracts starting at a 15% increase in level
of effort or 422 personnel with an option available for a 50% in-
crease in level of effort to 632 personnel.
U.S. EPA SUPPORT CONTRACTS 37
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Technical Enforcement Support Contracts
Nancy Deck
U.S. Environmental Protection Agency
Office of Waste Programs Enforcement
Washington, D.C.
WHAT IS TES
TES stands for Technical Enforcement Support. This covers
enforcement support at hazardous waste sites under the Compre-
hensive Environmental Response, Compensation, and Liability
Act (CERCLA) and the Resource Conservation and Recovery
Act (RCRA).
TES is the main contract mechanism for fulfilling and sup-
porting the enforcement activities of the Office of Waste Pro-
grams Enforcement (OWPE) and EPA's Regions for their pro-
grams relating to the implementation of the CERCLA and RCRA
laws. Four TES Contracts have been awarded to date.
WHAT TES DOES
The TES contractors provide technical support and the exper-
tise necessary to accomplish OWPE's mission. Examples of activ-
ities tasked under these contracts are:
Review of Technical Documents
LOIS Inspections
Facility Closure Plan Reviews
RCRA Facility Assessment
Comprehensive Groundwater Monitoring Evaluation
Comprehensive Evaluation Inspections
Enforcement Case Support
Expert Witness Support
Sampling Plans and Analysis
Compliance Oversight/Audits
Responsible Party Searches
Endangerment/Health Assessments
Records Compilation
Hydrogeologic/Geologic Studies
Title Search/Financial Assessments
THE TES CONTRACTS-
RESOURCES AND PERSONNEL
TES I
The first TES Contract was awarded to OCA Corporation on
June 9, 1983 and expired June 9, 1986. The TES I contract was a
Level of Effort (LOE) contract with a $14,649,129 capacity in its
3-year life. Their subcontractor team members were:
• Tech Law Inc.
• Metcalf&Eddy
• Clement and Associates
TES II
TES is a LOE contract. PRC (Planning Research Corpo-
ration) is the prime contractor. This contract was awarded
Sept. 30, 1984 with a 2-year base capacity of 539,000 LOE
hours and $24,718,577. The option year was exercised, effective
Oct. 1, 1986, with a capacity of 220,000 LOE hours and
$10,429,956. This contract will expire Sept. 30, 1987.
TES II subcontractors are:
Jacobs Engineering Group, Inc.
GCA/Alliance Technology
Versar, Inc.
Booz-Allen & Hamilton
ICAIR, Life Systems Inc.
Intera/Geo Trans
Putnam Hayes & Bartlett
TES II contract person—Nancy Deck, 382-3058.
TES III
TES III was awarded to Camp Dresser & McKee (COM) on
June 30, 1986. This is a cost-plus award fee contract. This con-
tract has a capacity of 52.5 million and 1,050,000 LOE hours,
over a 1-year base period and 2-year option period. This is a zone
contract which mainly covers Regions I-IV.
The subcontractors are:
Versar, Inc.
Booz-Allen & Hamilton
PRC
Techlaw, Inc.
Labat Anderson, Inc.
PriedeSedgwick, Inc.
Geoscience Consultants
SRA Technologies
Life Systems
Hydraulic & Waste Resources Engineers
AEPCO
Sobotka & Company
Geo Resources, Inc.
Lee Wan & Associates
Putnam Hayes & Bartlett
TES III contact is Linda Stewart, 382-2318.
TES IV
TES IV was recently awarded to Jacobs Engineering on
Sept. 26, 1986. This contract is also a cost-plus award fee con-
tract, and its capacity in LOE and dollar is the same as TES 111
This contract will mainly support Regions V through X.
Jacobs subcontractors are:
• Metcalf&Eddy
• TetraTech
• ICAIR Life System
• Kellogg Corporation
38
U.S. EPA SUPPORT CONTRACTS
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• Putnam, Hayes, & Bartlett
• Geo/Resource Consultants
• Battelle Pacific Northwest Laboratories
• Development Planning and Research Associates
KEY PERSONNEL USED IN THE
TES PROCESS
Some of the key personnel and their functions are:
• Contracting Officer—U.S. EPA headquarters employee with
sole authority to execute contractual agreement, redirect con-
tractor or modify terms of the contract.
• Project Officer—U.S. EPA headquarters employee in the
Office of Waste Programs Enforcement (OWPE) who pro-
vides the overall technical support and management of the con-
tract.
• Regional Coordinator—U.S. EPA employee with OWPE
who coordinates enforcement activities with a Region, OWPE
and the Department of Justice (DOJ).
• Regional Contact—U.S. EPA employee in the Regional Office
who coordinates TES enforcement activities for the Region.
• Primary Contact—U.S. EPA employee responsible for initia-
tion and monitoring of an individual work assignment.
• Program Manager—Contractor employee responsible for over-
all TES program operations.
• Work Assignment Project Manager—Contractor TES team
member responsible for planning, management and execution
of the services requested by U.S. EPA.
• Technical Monitor—Contractor employee responsible for tech-
nical work output of TES subcontractor team members
assigned by Program Manager.
• Contracts Manager—Contractor employee responsible for all
contractural and financial issues associated with the execution
of the TES contract.
ADMINISTRATIVE PROCEDURES FOR
PROCESSING WORK ASSIGNMENTS
At the beginning of each fiscal year the CERCLA and RCRA
Figure 1
Work Assignment/Work Plan Approval Process
programs plan what activities should be accomplished in that
year and what mechanisms to use.
If the contract vehicle needed is determined to be an existing
TES contract, the procedure begins using all the above-men-
tioned key personnel. The flow of the administrative procedures
is shown in the Work Assignment/Work Plan Approval Process
flow chart.
FUTURE CONTRACTS
To be discussed at the Conference.
OTHER CONTRACT VEHICLES
To be discussed at the Conference.
U.S. EPA SUPPORT CONTRACTS 39
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Contracting in the Superfund Removal Program
James Jowett
Linda Garcynski
U.S. Environmental Protection Agency
Emergency Response Division
Washington, D.C.
I. Background
A. The Superfund Removal Program
1. Scope 1980-1985
2. Scope 1986-future
a. Effects of Revised National Oil and Hazardous
Substances Contingency Plan
b. Effects of Superfund Off-site Disposal Policy
c. Effects of RCRA Land Disposal Regulations
and Use of Alternative Technologies
3. CERCLA Reauthorization
II. Overview of Contracting Efforts for the Removal
Program
A. Technical Support
1. 1980-1983
2. 1983-1986
3. 1986-1990
B. Cleanup Services
1. U.S. Coast Guard Basic Ordering Agreements for
Clean Water Section 311 Responses
2. Notice to Proceed Contracts for CERCLA
Activities
3. Emergency Response Cleanup Services Contracts
a. 1983-1986
b. 1986-1990
4. Regional-Specific Cleanup Contracts
a. Mini-ERCS
b. Media or Site-Specific Contracting
5. State-Lead Removals via Cooperative Agreements
6. Other Contract Types
III. Contract Features
A. Technical Assistance Team (TAT) Zone Contracts
1. Statement of Work
a. Management
b. Prevention
c. Contingency Planning
d. Training
e. Community Relations
f. Emergency Response
g. Special Projects
h. Analytical Support
2. Structure of Contract
a. Cost Reimbursable
b. Provisions for Award Fee
B. Emergency Response Cleanup Services (ERCS)
1. Statement of Work
a. Management
b. Containment
c. Cleanup and Disposal
d. Restoration
e. Analytical
f. Response Times
g. Equipment, Material, Labor Lists
h. Geographic Coverage
i. Capacities
2. Structure of Contract
a. Time and Materials, Indefinite Delivery
b. Provisions for Award Fee
c. Subcontracting
d. Daily Cost Documentation
e. Equipment Costs
C. U.S. EPA Management Structure
1. Contracting Office - Contracting Officers
a. Centralized Operation
b. Negotiating and Writing of Initial Contract
c. Obligation Authority
d. Administration of Contract
1) Modifications
2) Invoice Audits
3) Definitization of Delivery Orders
2. Program Office Project Officers
a. Differences Between Headquarters and Regional
Project Officers
b. Project Officer Duties
1) Developing Procurement Packages
2) Monitoring Performance
3) Invoice Certification
4) Management Reviews of Regions and
Contractors
5) Overall Technical Management and Direction
6) Coordination with Other U.S. EPA and
Federal Offices
7) Review of Key Personnel Qualifications
8) Coordinate Use of Multiple Contracts or Use
of Contracts in Multi-Region Zones
3. Regional Office - Deputy Project Officers
a. Issue Technical Direction Documents for TAT
b. Compile Performance Evaluations of
Contractors
c. Recommendations for Award Fees Based on
Performance in Region
d. Approval of TAT Special Projects
e. Monitoring Overall Contractor Costs for Region
f. Ensuring Contractor Follows Correct Manage-
ment Procedures
g. Reviewing Contractor Deliverable
h. Oversees OSC Use of Contractors
i. Authorizes TAT Analytical Services
j. Responds to Headquarters Findings on Manage-
ment Reviews
k. Oversees Contractor Management of
Government-Furnished Equipment
4. Regional Office On-Scene Coordinators
a. Regulatory Roles NCP
b. Contract Field Roles
1) Ordering Officer
2) On-site Direction
3) Daily Cost Monitoring
c. Performance Monitoring
1) Certification of Contractor Progress
2) Tracking Costs Against Project Ceilings
3) Developing Documentation on Contractor
Performance
4) Certification of Site-Specific Invoices
IV. Future of Contracting in the Removal Program
A. Future of Zone Structure
B. Scope of Future Contracts
C. Indemnification
40 U.S. EPA SUPPORT CONTRACTS
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ABSTRACT
The paper outlines developments in the Superfund removal
program that have affected the way the program contracts for
hazardous waste technical and cleanup support services. The
development of the Technical Assistance Team contracts and the
Emergency Response Cleanup services contracts is discussed. The
paper then addresses how the agency manages removal contracts.
Finally, the future of removal program contracts is described.
INTRODUCTION
The Comprehensive Environmental Response, Compensation
and Liability Act (CERCLA) was enacted in December 1980, and
was recently reauthorized by Congress and signed by the Presi-
dent on October 17, 1986. Commonly referred to as Superfund,
this act established a trust fund to clean up abandoned or uncon-
trolled hazardous waste sites. The new trust fund, $8.5 million
over the next five years, may be expended on two kinds of
response actions: short-duration removal actions are authorized
where immediate actions must be taken to address releases or
threats of releases of hazardous substances requiring expedited
response; longer-duration remedial actions are authorized to
reduce releases of hazardous substances that are serious, but not
immediately life-threatening. All Superfund responses are con-
ducted according to the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP). This paper focuses on con-
tracting in U.S. EPA's removal program.
Removal actions are short-term actions that stabilize or clean
up an incident or site which presents a threat to human health or
the environment. Such situations often involve fires or explo-
sions, direct human contact with a hazardous substance or con-
tamination of drinking water supplies. Typical response actions
include removing and disposing of hazardous substances, tem-
porarily relocating residents and controlling public access of peo-
ple to a hazardous waste site. Superfund originally limited remov-
al actions to six months in duration and $1 million in total cost.
The new legislation has raised these limits to 12 months and $2
million. Exemptions to these limits may be granted, if ap-
propriate. To date, 805 removal actions have been conducted
under Superfund by U.S. EPA at a cost of approximately $172
million.
SCOPE OF THE REMOVAL PROGRAM
AND CONTRACTING — 1986-FUTURE
By 1984, the agency had gained experience in the implementa-
tion of its removal and remedial programs. The 1982 NCP, while
providing a good framework for the Superfund program, re-
quired a reassessment based on the experiences of the subsequent
two years. One of the major changes made in the removal pro-
gram was the combination of the three categories of shorter term
response actions: immediate removals, planned removals and in-
itial remedial measures, into a single category: "removals." Be-
cause all three response categories of activities had similar scopes
of work and timeframes, it was believed that consolidation would
enable the Superfund program to accomplish more of these
removal actions with fewer regulatory hurdles. In February 1985
this consolidation was formally proposed. Its economic impact
was assessed and was determined to be minimal. In November
1985 the NCP amendments were published as a final rule and
became effective in February 1986.
These regulatory changes caused the removal program to begin
reassessing the mode of contracting currently in use. Utilizing
broad umbrella-type time-and-materials cleanup contracts was
determined to be inappropriate for some types of actions in this
new broad category of removals. Actions which allowed some
period of planning, albeit short, prior to initiation might lend
themselves to site-specific fixed price, or contaminant or media-
specific cost reimbursement types of contracts. As discussed later
in this paper, several significant changes were made in the con-
tracting methodology for the removal program.
In addition to regulatory changes, significant policy changes
have taken place during the last two years. The Superfund pro-
gram made a commitment to comply to the extent practicable,
with other applicable or relevant and appropriate environmental
standards and regulations. For the case of off-site disposal of
hazardous substances, this required that materials be sent to li-
censed facilities in compliance with the Resource Conservation
and Recovery Act (RCRA) or the Toxic Substances Control Act
(TSCA). Facilities accepting CERCLA waste must have been in-
spected and determined to be acceptable within six months of the
time of disposal. Implementation of this policy requires a site-by-
site determination by the On-Scene Coordinators (OSC) and their
RCRA or TSCA counterparts that the chosen off-site facilities are
appropriate for disposal and that the necessary permits would be
obtained.
Also developed in conjunction with this policy is the RCRA
program's phased development of land disposal restrictions or
"land ban" regulations. This program prohibits disposal of cer-
tain hazardous wastes in land disposal facilities, causing the
removal program to focus on the use of on-site alternative tech-
nologies to supplant land disposal.
CERCLA REAUTHORIZATION
Several significant changes to the 1980 CERCLA are contained
in the reauthorization legislation. The expanded statutory limits
may result in broader actions than those performed under the
former $1 million and 6-month limits. Contracting will change to
respond to these higher cost, longer response actions. Removal
actions, where appropriate, must also contribute to the efficient
performance of remedial actions; a waiver provision allows
removals to exceed the $2 million, 12-month ceiling if the removal
action to be taken is considered to be consistent with the remedial
action ancitipated for the site. These provisions have major ef-
fects on the future methods of contracting used by the removal
program.
CERCLA reauthorization provides that a response action con-
tractor will not be liable under CERCLA or any other federal law
for any damages which result from a release or threatened release
of a hazardous substance, except if the release is caused by the
contractor's negligence, gross negligence, or intentional miscon-
duct. While this precludes the application of strict liability under
federal law, it does not preclude state laws from subjecting
response action contractors to strict liability. CERCLA
reauthorization also provides the federal government with discre-
tionary authority to hold harmless and indemnify a response ac-
tion contractor against any liability for damages that result from a
release of a hazardous substance caused by the contractor's
negligence.
The reauthorized CERCLA also includes a rider that amends
Subtitle I of RCRA and creates a trust fund for responses to leak-
ing underground storage tanks. Although the leaking under-
ground storage tank program will primarily be a state-led effort,
it is envisioned that some limited federal presence will be
necessary for major public health emergencies. Because the
removal program is experienced in emergency response, emergen-
cy responses to underground tanks may be conducted using the
removal program and its contractors.
OVERVIEW OF CONTRACTING EFFORTS
FOR THE SUPERFUND REMOVAL PROGRAM
Successfully implementing emergency responses to releases of
U.S. EPA SUPPORT CONTRACTS 41
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hazardous substances requires extensive technical and cleanup
services in support of the federal On-Scene Coordinators (OSC).
Lacking the in-house resources to provide these essential services,
U.S. EPA has acquired technical assistance and cleanup support
through a network of contractor resources.
Technical Assistance
OSCs are provided technical assistance through the "Technical
Assistance Team (TAT) Contracts for Emergency Response,
Removal and Prevention." These contracts provide full-time
technical personnel in specified professional disciplines. At the
direction of U.S. EPA, TAT personnel provide a wide variety of
technical support services, including prevention, contingency
planning, training, response monitoring, response documentation
and analytical support.
The first TAT contract was awarded to Ecology and Environ-
ment, Inc. on April 10, 1979, for limited support of the oil spill
prevention and emergency response program under Section 311 of
the Clean Water Act. Eleven TAT offices were established to sup-
port each U.S. EPA regional office and the Environmental
Response Team (ERT) in Edison, N.J. These offices were staffed
by a total of 32 TAT personnel. With the enactment of Super fund
in December 1980, new work initiatives involving releases of
hazardous substances imposed a substantial additional workload
on the emergency response program. Accordingly, the agency
upgraded the TAT contract to provide response support at hazar-
dous waste sites. By the end of the original TAT contract in
December 1982, TAT was staffed by 112 technical personnel in 32
professional disciplines.
A successor TAT contract was awarded to Roy F. Weston, Inc.
in October 1982. This contract established 20 TAT offices sup-
porting numerous U.S. EPA facilities, and provided the full
range of technical services required to support the Superfund
removal program. Reflecting an increase in Superfund activities,
TAT contract staff grew from 112 to 198 full-time personnel. By
the end of the Roy F. Weston, Inc. TAT contract in January
1987, over 13,000 technical assistance tasks will have been per-
formed at a cost of $50 million.
In anticipation of an expanded Superfund removal program
due to CERCLA reauthorization, the agency is continuing to
upgrade the capabilities of the TAT program. The successor to
the Roy F. Weston, Inc. contract is being procurred under two
separate TAT contracts. One contract (Zone 1) will provide TAT
services in U.S. EPA Regions I through V, ERT and head-
quarters. A second contract (Zone 2) will provide TAT services in
Regions VI through X. These contracts provide initial TAT staff-
ing of 235 people, with provisions for permanent annual growth
and optional temporary personnel increases. The contracts also
expand the scope of support services, including limited emergency
response implementation, RCRA and TSCA inspections, mini-
remedial investigations and enhanced analytical support. It is an-
ticipated that the TAT zone contracts will be able to accom-
modate an expanding removal program through 1990.
Cleanup Services
In addition to technical assistance, OSCs require equipment,
materials and personnel to physically remove and dispose hazar-
dous substances. This cleanup support is provided through
several contractual mechanisms.
As an interim measure, U.S. EPA implemented Notice to Pro-
ceed (NTP) emergency procurement procedures in 1981 to obtain
cleanup services. Two hundred seventy NTPs were issued at a cost
of over $45 million. NTPs were preliminary contractual
documents awarded by OSCs and meant to be replaced by
definitive contracts negotiated by U.S. EPA Contracting Officers
(COs). While NTPs were effective in obtaining timely cleanup ser-
vices at removal sites, they had several drawbacks. Contractors
were not under any pre-negotiated obligation to provide cleanup
services, so cleanup arrangements were made on a site-by-site
basis. NTPs were awarded non-competitively; and, U.S. EPA did
not generally negotiate contract rates until performance under the
NTP was complete, placing the CO at a disadvantage when
negotiating final rates and terms of the NTP.
In 1983 and 1984, U.S. EPA awarded four Emergency
Response Cleanup Services (ERCS) zone contracts, supplanting
the NTPs. Zone 1 was awarded to O.H. Materials, Inc., and pro-
vides cleanup services in Regions I-III; Zone 2 was awarded to
HAZTECH for Region IV. Zone 3 was awarded to PEI for
Region V; Zone 4 was awarded to Reidel Environmental
Emergency Services for Regions IV-X. The ERCS zone contracts
provide an indefinite quantity, of specific services, equipment and
materials during the contract period. Each contract ensures that
U.S. EPA will order a stated minimum quantity of services, and
that the contractor will furnish the minimum and any additional
quantities, not to exceed a stated maximum. To date, these con-
tracts have provided cleanup services for 472 responses at a cost
of over SI 12 million.
During the next two years, U.S. EPA will increase the number
of ERCS zone contracts. Many of these contracts will provide
cleanup services to only one U.S. EPA Region, as opposed to
multi-regional coverage. It is anticipated that this approach will
enhance competition and accommodate an expanded removal
program due to CERCLA reauthorization.
U.S. EPA is also awarding several separate ERCS contracts to
provide the regions with additional contractor resources to con-
duct removal actions. Like the zone contracts, each ERCS
regional contractor will be responsible for both response-related
and program management-related services. The Statements of
Work for the zone contracts and regional contracts are essentially
identical; however, the regional ERCS contracts generally will re-
quire fewer resources, smaller geographic coverage and less
stringent response times.
In addition to ERCS regional contracts, U.S. EPA will pursue
media or site-specific contracts when appropriate, particularly
when specific removal activities are conducted on a recurring
basis in a specific geographic area of the country. Missouri diorin
cleanup contracts in Region VII exemplify this situation. When
site characteristics are well defined and sufficient time is
available, U.S. EPA will compete site-specific, fixed price con-
tracts. Media or site-specific contracting allows U.S. EPA to ob-
tain more accurate contract rates and enhance overall competi-
tion.
Since the revised NCP consolidated removals, the agency con-
sidered developing cooperative agreements with states to conduct
removal actions. States had conducted initial remedial measures
under cooperative agreements during the years prior to the recent
NCP amendments and there was no desire to eliminate this op-
portunity for state participation and responsibility. A work group
is currently developing guidance for states to conduct non-tune
critical removal actions (i.e., removal actions can be deferred 6
months or more) at both National Priorities List (NPL) and non-
NPL sites under cooperative agreements.
In addition to the changing structure of removal program con-
tracts, a policy decision was made to allow use of remedial pro-
gram contracts or state-led contracts for conducting certain non-
time critical removal actions. These actions, known as expedited
response actions (ERAs), consist primarily of actions previously
identified as initial remedial measures. Site-specific subcontrac-
tors for these responses will be procured under the remedial con-
tracts on a sealed-bid, fixed price basis. Another paper entitled
"EPA's Expedited Response Action Program," presented at this
42 U.S. EPA SUPPORT CONTRACTS
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conference, provides greater detail on ERAs.
CONTRACT FEATURES
Emergency Response Cleanup Service Contracts (ERCS)
The current ERCS contracting structure is undergoing recom-
petition. The four zone structure remains unchanged and the
scope of the recompeted contracts remains similar to that of the
current contracts. Minimum and maximum amounts of cleanup
services are to be ordered under indefinite quantity, indefinite
delivery provisions.
The contractors supply all personnel, materials and equipment
specified in the Delivery Order to conduct removal actions. In ad-
dition, the new contracts will permit support for responses to
leaking underground storage tanks to be conducted. Support is to
be available to the OSC or other federal agent on a 24-hours per
day basis.
An elaborate structure of response time requirements is
specified in the contracts, which will ensure that the agency has
complete national coverage in the event of an emergency; any
delay in mobilization might place the public health at significant
risk. Stringent response times are not necessary for all removal ac-
tions, but coverage must be available at all times for the "classic
emergencies." Historically, 11 to 15 percent of all removal actions
are classic emergencies.
Each contract has a zone program manager (ZPM) and staff to
ensure that the scope of work is being implemented and that
response time requirements are being met. The ZPM oversees the
hiring and distribution of cleanup personnel, maintains cost
records for all responses, manages the submission of required
reports, manages the quality assurance program, and ensures that
all administrative tasks are implemented. The ZPM is the key
focal point for communication with the agency.
Each site response is assigned a response manager. The re-
sponse manager oversees implementation of the site-specific re-
sponse under the Delivery Order and works directly with the OSC
in conducting cleanups. All ERCS contractor activities on-site are
subject to the supervision of the response manager.
The ERCS contractor negotiates hourly, weekly and monthly
rates for equipment, personnel and materials. Equipment,
materials and labor are listed with fixed or provisional rates based
on the program's historical experience and the anticipated fre-
quency of their use. The new ERCS contracts will change the ap-
proach to certain previous fixed rate items, requiring them to be
included as overhead charged to the agency instead of as a direct
charge to the agency. Rates lists are constantly being refined
based on the agency's historical uses of equipment and personnel.
One key element of the new ERCS contracts is the subcontrac-
ting of transportation and disposal. Previously, all transportation
and disposal services were subcontracted. Under the new con-
tracts, the OSC will be permitted to use the prime contractor for
transportation activities costing up to $5,000, based upon the
OSC's best professional justment that using of the prime will be
more cost-effective than using a subcontractor. For all activities
related to transportation and disposal, the CO may waive the sub-
contracting requirement, enabling the prime to provide transpor-
tation or disposal services. The OSC must determine that the costs
quoted by the prime are the appropriate choice in relationship to
bids by potential subcontractors, and that no conflict of interest
will occur by using the prime for transportation or disposal.
The contractor is also responsible for analyzing contaminated
materials to aid in determining appropriate disposal or other
response measures. The turn-around required for samples
analysis is frequently very short due to the urgency of the situa-
tion. U.S. EPA's contract laboratories are generally unable to
supply the quick turn around analytical services required; there-
fore, ERCS must provide this service.
A significant change to the contract structure is the addition of
an award fee. The previous contracts provided only incentive
fees. As the award fee is implemented, contractor efficiency and
effectiveness will be evaluated, with the fee based on this evalua-
tion. The agency expects that this award fee, which will also
replace the previous handling charge for subcontracting, will be
the primary motivation in improving contractor performance.
Subcontracting support will be reimbursed to the prime con-
tractor at cost. A list of items not allowable as direct costs to the
contract has been developed; other items have been listed which
will not be paid for at fixed rates, but for which the contractor
will be reimbursed at cost. Other improvements to the provisions,
such as holiday and overtime pay, have been added. All costs will
be logged on a daily cost tracking sheet which the OSC must
verify. U.S. EPA has developed a software system to aid the OSC
in tracking costs and is encouraging the contractors to use the
system. The agency plans to look at requiring cleanup firms to
develop accounting systems that document all charges based upon
cost.
The future ERCS contracts will be augmented by the regional-
specific ERCS or mini-ERCS contracts, as well as site-specific or
contaminant/media-specific contracts. The agency anticipates
further diversification of the contracting structure as time allows.
Technical Assistance Team (TAT) Zone Contracts
The TAT contract provides technical support to OSCs for
response to releases of oil and hazardous chemical substances.
Each TAT zone is managed by a ZPM. The TAT ZPM is the
single point of contact with the U.S. EPA Project Officer (PO)
and CO, and is responsible for: planning and executing all efforts
performed under the contract; managing and supervising TAT
Leaders; preparing and submitting required requests; monitoring
all contractor costs; managing property; and ensuring overall
quality control. Within each TAT zone, each office is managed by
a TAT Leader (TATL). This individual is the single point of con-
tact with the regional EPA Deputy Project Officer (DPO). The
TATL has overall management and supervisory responsibility for
team members. The TATL also receives and implements technical
direction issued by the DPO; ensures that all quality assurance
and chain-of-custody procedures are met; maintains all records;
obtains any special services not available from within a TAT of-
fice; provides for rapid turn-around laboratory analysis; develops
and implements team and site safety plans; and maintains a
24-hour, 7-day-a-week response capability.
Prevention activities performed by TAT usually involve non-
transportation-related facilities that produce, refine, store and
distribute oil and hazardous substances. TAT activities also in-
clude conducting facility surveys and inspections under the Spill
Prevention, Control and Countermeasures Program, assists the
OSC in preparing Notices of Violation for violations detected
during inspections, and documenting cases. Planning activities
are also taken by the TAT to prepare and review federal, regional,
state and local emergency response contingency plans.
Other TAT activities include: training of EPA, state, local and
contractor emergency response personnel in response procedures
such as personal safety, data systems, decontamination and com-
munity relations; providing media relations support, such as
arranging news conferences, distributing news releases and
developing fact sheets; performing minor hazardous waste release
containment efforts not exceeding $1,000 in cost such as emergen-
cy pumping and sorbent booms deployment; obtaining special
projects for equipment, services and personnel, studies not
routinely available on the TAT, such as renting aircraft or all-
terrain vehicles, providing temporary housing for evacuees, or
U.S. EPA SUPPORT CONTRACTS 43
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providing expert witnesses. The TAT contract also provides rapid
turnaround laboratory or field analysis by collecting, storing,
transporting, analyzing and disposing samples.
The TAT zone contracts are Cost-Plus-Award-Fee (CPAF)
contracts which pay the contractor the actual allowable cost in-
curred in performing required work up to the estimates of total
costs established in the contract, a fixed, base amount fee which
does not vary with performance, and an award pool distributed
based on subjective evaluation by U.S. EPA of the contractor's
performance. Performance measures consider the areas of project
planning, technical competence and innovation, scheduling and
cost control, reporting, resource utilization and overall effort.
EPA Management Structure
Contracting Office — Contracting Officers
U.S. EPA's contracting office, the Procurement and Contracts
Management Division (PCMD), centralized in headquarters, has
the authority to develop requests for proposals (RFPs) or invita-
tions for bid (IFBs) in accordance with the Federal Acquisition
Regulations (FAR). For contracts in the removal program, pro-
ject officers in the Emergency Response Division (ERD) develop a
technical statement of work; projection of needs that considers
personnel, materials or equipment; an estimated budget; and
technical evaluation criteria. Procedures for quality assurance
and treatment of confidential data are also supplied by the pro-
gram. PCMD takes this information and determines the ap-
propriate contract vehicle to develop the IFB or RFP.
The Contracting Officer (CO) evaluates proposal information
on cost, accounting and other contractual grounds; and the pro-
gram office, with regional participation, evaluates technical
aspects of the proposals. Negotiations with the proposer follow
and, upon completion of these negotiations, the CO enters into
the contract. At that point, the CO begins administration of the
contract.
The CO may modify the contracts, close out delivery orders in
the case of ERCS (i.e., definitization), resolve disputes with con-
tractors regarding any terms, conditions or payments, and con-
duct audits of records to determine the accuracy of invoices. The
CO serves as the final arbiter on issues concerning either the TAT
or ERCS contracts.
Program Office — Project Officers
The headquarters Project Officers (POs) (or in the case of mini-
ERCS, regional POs) serve as the final technical authority on the
contracts. The POs develop technical information for the com-
petition process and evaluate all proposals in conjunction with
their regional counterparts. The POs also serve as technical con-
sultants during negotiations.
The POs monitor contract performance, and serve as liaison
between the OSC and the contractor when technical issues arise.
The POs monitor costs, evaluate contractor performance for
award fee recommendations and monitor expenditures against the
contract ceilings. The POs also certify invoices for payment.
The POs perform in-depth management reviews of compliance
with contract terms by the contractors, the regions and the OSCs.
A formal report is drafted, comments considered and final find-
ings developed. A copy of the findings is sent to the Office of the
Inspector General.
The headquarters POs also act in a coordination role with other
federal agencies. This may occur when other agencies wish to use
U.S. EPA contracts, or when they begin developing contracts for
their agencies.
The POs review and approve or reject key personnel to work
within the contract. This effort entails reviewing of resumes and
comparing qualifications to those required by the contract.
The headquarters POs will also assist the regions in determining
which among the ERCS, mini-ERCS or other contracts are the
most appropriate for conducting the cleanup. This may involve
consideration of conflict of interest issues.
In summary, the POs serve as a liaison between the contracting
office and the regional offices, dispensing assistance on issues
related to site-specific responses in the context of the requisite
contracts, A PO may travel, attend meetings and seminars and
provide training in this role, as well as performing day-to-day,
routine aspects of the job.
Regional Office — Deputy Project Officers
In each U.S. EPA regional office, ERT and headquarters,
Deputy Project Officers (DPOs) have program management
responsibilities for planning, executing and controlling the use of
the TAT and ERCS contracts. DPOs interface daily with TATLs
and ERCS ZPMs. DPOs ensure that contractors in their region
provide the OSC with all necessary technical and cleanup support
required during emergency responses. Other DPO responsibilities
include: providing technical direction and oversight; issuing
Technical Direction Documents (TDDs); coordinating the re-
gional performance evaluation process; implementing head-
quarters and regional contract management policies and technical
guidance; receiving and reviewing all contractor reports, such as
monthly status and financial reports, and receiving, reviewing and
distributing monthly contractor invoices.
Regional Office — On-Scene Coordinator
The On-Scene Coordinator (OSC) is defined by the NCP as the
federal official predesignated by U.S. EPA or USCG to coor-
dinate and direct federal responses under Superfund. All TAT
and ERCS technical and cleanup support services are performed
under the control of, and in support of the OSC. While OSC
responsibilities encompass a very broad range of emergency
response activities, the OSC has some specific contract manage-
ment functions. The OSC prepares the Delivery Order statement
of work and estimates the project ceiling amount. The OSC also
directs and monitors ERCS contractor activities, reviews and cer-
tifies ERCS invoices, evaluates ERCS contractor performance at
the end of each Delivery Order and, if warranted, prepares ERCS
incentive award nominations.
The OSC directs and oversees on-scene technical support ser-
vices provided by TAT members. This includes requesting TAT
support from the DPO, directing TAT activities during emergen-
cy response efforts and evaluating TAT performance on a
quarterly basis.
The OSC must ensure that removal contractor costs are
justifiable and adequately documented to substantiate removal
decisions and expenditures. The OSC's role in contractor cost
control includes: projecting funding and costs for ongoing ERCS
Delivery Order and TAT TDDs; monitoring and verifying the
quantities of ERCS cleanup equipment, materials and personnel
used during removal actions; tracking contractor costs against
project ceilings; and documenting contractor activities through
the use of logs and work reports.
CONCLUSION: FUTURE OF CONTRACTING
IN THE REMOVAL PROGRAM
Future of Zone Structure
As stated in previous sections of this paper, the scope of the
removal program has greatly increased since 1980 and the passage
of the original CERCLA. Changes in the new legislation will con-
tinue this trend. The contracting structure will consequently re-
quire further diversification to meet the needs of increased scope-
The Emergency Response Division and the Procurement and
44 U.S. EPA SUPPORT CONTRACTS
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Contracts Management Division are undertaking several in-
itiatives. A possible division of the ERCS structure into smaller
zones is being carefully examined, based on quantity and com-
plexity of work in the various U.S. EPA regions.
Further assistance to OSCs for contract management is being
reviewed. Additional mini-ERCS or site-specific contracts will be
used where the need arises. The TAT contract level of support to
the OSC will be increased, enabling the OSC to better control site
activities, and engineering evaluations/cost analyses may be
undertaken to better define solutions to cleanup problems on
complex sites.
Scope of Future Contracts
The scope of future ERCS contracts will become more limited.
ERCS will primarily be used for conducting cleanups where site
responses are needed in short time frames. Regional contracts will
contain requirements for longer response times, and those sites
where action can be delayed for a few months may be competed
site-specifically using expedited procurement methodologies. In
general, the removal program intends to more fully define the
types of cleanup services required and to develop varying scopes
of work and contract types to meet these needs without sacrificing
protection of public health and the environment. In this way, the
agency hopes to further stimulate market development of cleanup
services to meet the continuing demands of the future Superfund
removal program.
U.S. EPA SUPPORT CONTRACTS 45
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Improving and Implementing Superfund
Contracting Strategies
Stanley P. Kovell
U.S. Environmental Protection Agency
Office of Emergency & Remedial Response
Washington, D.C.
The U.S. EPA is currently evaluating its basic contract strategy
and operational plans to perform Superfund activities, in an-
ticipation of Superfund reauthorization requirements. It is evi-
dent that any reauthorization effort will most likely necessitate an
overall increase in specific site-related investigations and cleanup
actions. Specifically, this effort will require:
• Improving existing contract structures and existing contract
management institutions
• Developing and implementing alternative contract structures
and contract management institutions
• Identifying and escalating "institutional barriers" to an ap-
propriate level of management for resolution
• Reducing the level of operational "hand off" to ensure pro-
gram responsibility and accountability
• Adapting the agency infrastructure to correspond to the change
in contracting structures
The evaluation and modification of current contracting struc-
tures is necessary to improve the pace, quality and cost-
effectiveness of site cleanup actions, in response to the anticipated
expanded scope resulting from Superfund reauthorization.
This paper will report on the progress of models being
developed and policy decisions being made concerning site-
specific investigations and cleanup actions.
46 U.S. EPA SUPPORT CONTRACTS
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Addressing the Consultant's Liability Concerns
Laurence T. Schaper, P.E.
Dennis R. Schapker, P.E.
Black & Veatch Engineers-Architects
Kansas City, Missouri
ABSTRACT
The consultant's desire to provide engineering services in the
hazardous waste field is tempered by its present difficulties in
properly managing the liability risks inherent in hazardous waste
work. Approaches to minimize the probability of potential cat-
astrophic financial loss while providing the engineering services
needed to clean up hazardous waste sites are discussed.
The problem is illustrated by the inability to obtain some types
of liability insurance, higher deductible amounts, lower upper
limits of coverage and substantially higher policy costs.
Tort reform is an essential but long-term approach to a rational
resolution of the liability issue. Tort reform legislation already
has been passed or is pending in a large number of states. Key
categories in which the states are beginning to provide legislative
relief include: limiting joint and several liability and placing a
cap on damage awards, especially as applied to non-economic
damage.
A majority of the litigation against consultants stems from
alleged design error. Quality control programs are being ex-
panded to address this area of concern.
Indemnification by the client provides a means of protecting
the consultant from undue risk. Indemnification language devel-
oped by the American Consulting Engineers Council is suitable
for hazardous waste contracts. However, many states have anti-
indemnification statutes that prevent a party from being pro-
tected against its own negligence. Therefore, caution should be
exercised when contemplating the use of indemnification as a risk
management tool.
INTRODUCTION
Unenlightened and often intentional disposal practices involv-
ing hazardous wastes have resulted in major environmental pollu-
tion. Extensive news media coverage of the problems caused by
hazardous waste mismanagement continues to increase public
awareness and support for the Superfund Program to clean up
dangerous hazardous waste disposal sites.
It is axiomatic that the country's best interest is served by hav-
ing the highest quality engineering talent heavily involved in
analyzing and developing solutions to hazardous waste problems.
To obtain engineering talent, it is essential that liability risk asso-
ciated with involvement in hazardous waste work be manage-
able. Many consultants, fearing financial ruin, have not partic-
ipated in hazardous waste cleanup due to the inability to ade-
quately protect against the liability risk involved. Other consul-
tants participating in hazardous waste work are investing substan-
tial time and resources to minimize this risk. This paper dis-
cusses the methods of addressing the consultant's liability con-
cern and identifies available techniques to manage the risk.
The first step in identifying useful techniques for risk man-
agement is to gain a clear understanding of the problem. The
initial section of the paper defines the nature and extent of the
consultant's liability concern. The remainder of the paper is de-
voted to discussion of the potential risk management techniques
which include:
• Captive insurer
• Tort reform
• Minimizing risk
• Indemnification by the client
PROBLEM DEFINITION
It is often said that a design firm's clients are its greatest asset.
In recent times this truism has proved to be a double-edged
sword. Between 40-50% of all claims have been brought against
the design professional by his greatest asset—owners.
Although specific percentages vary from year to year, Table 1
gives an approximate breakdown of claims brought by various
parties against design firms:
Table 1
Breakdown of Claims Filed Against Engineering Firms
Claims Brought By
Owners
Contractors
Other Design Firms
Other 3rd Parties
40-50%
20-25%
5-10%
25-35%
These professional liability claims can be analyzed also on the
basis of cause. Table 2 shows this breakdown:
Table 2
Types of Claims Filed Against Engineering Firms
Claims Involving
Personal Injury
Design Error & Failures
Contract Disputes
15-25%
50-60%
15-25%
Although the statistics shown in these tables can help focus
claim reduction efforts in the most beneficial directions, the bare
numbers do not explain the current professional liability insur-
ance problem, especially in the area of hazardous and toxic waste
work. Symptoms of this problem include: reduction of the num-
INDEMNIFICATION & COSTS 47
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ber of firms offering professional liability insurance; increasing
premium cost and reduction of coverages (in some areas, such
as pollution claims, coverage has been completely eliminated);
and increasing deductible limits.
The cause of the current problem results from the interaction of
two disparate factors:
• Insurers' use of cash flow underwriting
• Continued expansion of liability under U.S. tort law
In the recent past, high interest rates allowed insurers to use
cash flow underwriting which utilizes investment income earned
from premiums to make up for any difference between actual
losses and premium income. However, once interest rates de-
clined, investment income was insufficient to cover insured losses.
The result was a predictable rise in the cost of insurance.
Although the expansion of tort liability is by no means taking
a straight course, the general trend of our common law (judicial
decisions) is toward compensating injured victims at the expense
of insurance companies. This trend produces results which are un-
expected and, hence, unfunded by insurers. The prospects of
huge losses in cases such as Agent Orange, asbestos and other
product liability suits have resulted in the insurance industry's
complete withdrawal from the area of pollution damages for de-
sign professionals.
Whether insurance companies are partially responsible for the
consultant's liability problems as well as the role they will play in
providing solutions are controversial issues. It is not important
here to judge the wisdom or- integrity of the insurance industry,
but rather to understand the impact of insurance, or lack thereof,
on the consultant's liability dilemma.
The two types of insurance policies carried by most consultants
are:
• Comprehensive General Liability
• Professional Liability
Comprehensive general liability provides protection against
bodily injury and property damage claims which result from an
occurrence as set forth in the policy. Professional liability insur-
ance provides protection against errors, omissions and negligent
acts which arise out of the performance of professional services.
Professional liability insurance, until recently, was available from
a significant number of carriers. The insurance industry problems
have resulted in only two major carriers now offering profession-
al liability insurance. These are:
• Design Professionals Insurance Company
• Victor O. Schinnerer & Company
The insurance industry has been plagued by poor financial per-
formance in recent years. The March 10, 1986 issue of Business
Week reported insurance industry losses in excess of $2 billion in
1984, $5 billion in 1985 and $2 billion in 1986.
A recent survey sponsored by the American Consulting Engi-
neers Council and other groups revealed the consequences of such
a performance. Liability insurance rates for consultants increased
an average of 48% last year. Higher deductible limits and higher
insurance premiums reduce profitability; however, an even great-
er concern is the lower total coverage which can be obtained. This
reduced coverage is caused by a withdrawal from the market by
various reinsurers. (Reinsurers provide the excess layers of cover-
age above the primary policy limits.) The effect of the reinsur-
ers' actions is a lack of protection against catastrophic loss.
For some perils such as asbestos and pollution-related losses,
not even primary coverage is available. Since the 1960s, pro-
fessional liability policies have been written on a claims made
basis. This means the insurance company pays claims which occur
during the policy period but will not pay claims which occur after
the coverage is terminated. Therefore, even if a consultant had
coverage for hazardous waste work at the time the work was per-
formed, the consultant is now totally exposed under current pol-
icies. The pollution exclusion in current policies utilizes a very
broad definition of pollution:
Pollutants are defined as any solid, liquid, gaseous or
thermal irritant or contaminant, including smoke, vapor,
soot, fumes, acids, alkalis, chemicals and waste. Waste
includes materials to be recycled, reconditioned or re-
claimed.
The exclusion applies to claims or claim expense arising out of
the actual, alleged or threatened discharge, dispersal, release or
escape of pollutants.
It appears unlikely that insurance companies will provide cov-
erage for pollution-related claims in the forseeable future. Paul
Genecki is referenced in a May 1986 Engineering Times article
as stating that a turnaround is not expected soon. He indicate:
that providing insurance for pollution claims would require sev-
eral reforms including the following:
• Rescind application of the joint and several liability standard
• Clarify who owns pollution, both now and in the future
• Provide specific quantitative safety standards established by a
federal agency. These standards must indicate what is and is
not legally safe, both now and in the future.
If it is not possible to obtain adequate pollution insurance
coverage, then other means of providing protection against
potentially devastating claims must be utilized.
CAPTIVE INSURER
The inability to obtain coverage on work involving pollution
has provided incentive to consider self-insurance pooh or captive
insurance companies. The concept has been implemented by the
National Solid Waste Management Association for hazardous
waste contractors. A similar approach has been seriously con-
sidered by the American Consulting Engineers Council (ACEQ.
The concept currently is being evaluated by the Hazardous Waste
Coalition, a group of consulting engineering firms.
Tax laws influence the economic viability of forming captive
insurance companies. Insurance premiums are generally tax de-
ductible. However, a March 24, 1986, article in Forbes Magazine
states that payments to self-insurance reserves are not tax de-
ductible. The article notes that claims from a firm's self insur-
ance reserves can be deducted, but only when the claims are ac-
tually made. Thus the Internal Revenue Service receives taxes
on the interest earned by the reserves. The IRS position is being
challenged and the Supreme Court will hear the case.
TORT REFORM
Tort can be defined as a violation of a right not rising out of a
contract, or a private or civil wrong or injury. Under traditional
tort law, the injured person is compensated only if the guilty party
can be specifically identified. However, recent awards have been
made to injured persons even when a specific party cannot be
identified. The trend toward very large awards to injured persons
has caused much concern. The situation has been described by
Paul Wenske as follows:
The civil court system is out of control, juries are run-
ing amok and courts have fashioned new theories of lia-
bility that have turned the court system into an ineffic-
ient social welfare giveaway.
The other side of the argument has been described by a Kansas
48 INDEMNIFICATION & COSTS
-------
plaintiff attorney as follows:
The corporate world is amoral. If it costs more to be
safe than dangerous, they're going to be dangerous.
Regardless of the reader's perspective, the inefficiency of the
existing tort system is disturbing. A Rand Corporation study in-
dicates that in asbestos cases only about one-third of the total
money goes to victims.
There is widespread belief that tort reform is needed. A De-
partment of Justice study recommends the following reforms:
• Return to fault based standard for liability
• Require causation findings be based on scientific and medical
evidence
• Eliminate joint and several liability in certain cases
• Limit non-economic damages (such as pain and suffering) to a
reasonable amount
• Limit attorneys contingency fees
• Provide periodic (rather than lump sum) payments of damages
for future medical care or lost income
• Reduce awards where compensation also will be made from
other sources
• Encourage alternative dispute resolution methods to resolve
cases out of court
The enactment of new legislation at both the state and Fed-
eral levels takes a massive effort by a large number of groups.
One coalition of groups working to achieve tort reform at both
the state and national levels is the American Tort Reform Asso-
ciation (ATRA). Associations that include large numbers of con-
sultants as members and that are members of ATRA include the
National Society of Professional Engineers, American Consult-
ing Engineers Council, American Society of Civil Engineers and
the American Water Works Association. The ATRA serves as an
information clearinghouse for each member association.
Tort law has traditionally been controlled by state law.
Approximately 95% of tort cases are tried in state courts. For
this reason, much of the effort to reform tort law occurs at the
state level. There is tremendous activity in tort reform as indi-
Table 3
Partial History of States that have Passed Tort Reforms
Type of Action
State
Modifies or
Limits
Joint &
Several Liability
Cap on
Damage
Awards
Cuts
Insurance
Premiums
California
Colorado
Florida
Kansas
Maryland
Michigan
Minnesota
Missouri
New Hampshire
New York
South Dakota
Utah
West Virginia
Washington
* cn
X 250, 000 l '
450,000,. X
Varies u;
350,000?!}
X 225, OOO1- ;
1 b)
400,000),:
350,000),j
875, OOO1 '
* /3\
1,000,000),'
X 1, 000, 000 ^
i,ooo,ooo(3)
X Tied to life
Expectancy
(1) Applicable to non-economic damage (i.e., pain and suffering)
(2) Medical malpractice—$250,000; non-economic—$1,000,000; limit for all losses—$3,000,000.
(3) Medical
(4) Intangible losses excluding pain and suffering
cated by the fact that more than one-half of the states are work-
ing on proposed legislation.
A substantial number of states have passed legislation which
addresses tort reform. Table 3 contains a partial list.
In addition to the activity at the state level, there has been Fed-
eral involvement. A Tort Policy Working Group was established
by the Attorney General and consisted of representatives from 10
agencies and the White House. The group issued a report in Feb-
ruary 1986. The report noted the extraordinary growth of the
number of tort lawsuits and the average award per lawsuit. The
group concluded tort law is a major cause of the insurance avail-
ability/affordability crisis and also determined action by the Fed-
eral government was appropriate and necessary.
An example of proposed Federal legislation is the Litigation
Abuse Reform Act (S. 2046). Provisions of the bill include limita-
tions on damages for non-economic losses, contingency fee agree-
ments and awards for punitive damages. The legislation would
cover alleged negligence by consultants where damages are sought
for physical injury or mental pain or suffering.
The effect of tort reform on the availability and cost of liabil-
ity insurance for consultants is somewhat uncertain. Insurance
industry spokesmen indicate that tort reform will expand the gen-
eral availability of casualty/liability coverage. However, the most
critical void in available coverage, pollution coverage, will not
be resolved soon, even with passage of tort reform legislation at
the state and Federal levels. An explanation for the limited impact
of tort reform on consultants is stated by Stefan Jaeger in the
June 1986 issue of Engineering Times. Jaeger's article states that
only about 20% of damage claims paid on engineer's policies
stem from personal injury suits. Most of the claims paid are the
result of property damage and breach of contract suits. The dam-
age and fee limit contained in tort reform legislation would not
greatly reduce the claims paid in the property damage and breach
of contract suits.
MINIMIZING RISK
Minimizing risk is an important part of the consultant's pro-
gram to address the liability concern. Important elements of the
concept include the following:
• Evaluate types of work performed
• Execute a carefully written contract
• Provide quality control
• Document communications
• Use proven contract documents
• Understand and utilize the fundamentals of conflict resolution
The engineer must recognize and evaluate the tendency for cer-
tain types of work to lead to litigation. Traditional problem areas
include services for dams and tunnels. Current concerns include
asbestos removal and land disposal of solid and hazardous waste.
Much of the concern involves uncertainty regarding future conse-
quences. Will employees working on an asbestos removal pro-
ject bring suit over alleged health problems 25 yr in the future?
Will leachate from a land disposal site pollute a drinking water
supply? In either event, the probability of insurance covering liti-
gation costs and damage claims is remote. Thus, the consultant
must understand the risks and implement strategies to limit risk to
acceptable levels.
A key to minimizing the consultant's risk is to negotiate and
execute well-written contracts for engineering services. The con-
tract should clearly define the scope of services to be provided.
Many problems can be avoided by ensuring that both the consul-
tant and the client have the same understanding as to what will be
provided to the client. Although many consultants tend to view
the non-engineering portions of contracts as mere "boilerplate,"
INDEMNIFICATION & COSTS 49
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failure to properly draft and review the entire contract with com-
petent legal assistance can result in unexpected liability. Legal re-
view and assistance during contract preparation should be stan-
dard practice on projects involving hazardous waste site cleanup.
Once a sound contract has been written, the consultant's atten-
tion should be devoted to providing high quality work products.
Employing qualified personnel is a fundamental step in producing
high quality work. Hazardous waste work requires specialists in
the areas of hydrogeology, chemistry, industrial hygiene and
engineering. Firms not having the required expertise on their own
staff must utilize other consultants to supplement their needs.
Personnel training and technology transfer also are essential.
Hazardous waste cleanup techniques are rapidly changing and
therefore new to many engineers. The skills required for haz-
ardous waste cleanup services can be developed through atten-
dance at meetings and seminars, reading the technical literature
and communication with those knowledgeable in the field.
A basic element in quality control is review of work products
by experienced personnel that are independent from the work
product. Errors and omissions can be reduced greatly by inde-
pendent reviews of reports, design memoranda, drawings and
specifications.
Documenting communications should be a part of the consul-
tant's program to minimize and control risk. All significant tele-
phone calls and conferences should be documented in writing.
Design memoranda outlining the approach to the project and
major design parameters should be written early in the project
and updated as needed. All key decisions and changes in agree-
ments should be recorded. It is important that written communi-
cations not include cryptic, trite or cute notes or comments. These
unnecessary or inaccurate comments may be difficult to explain
to a jury in a subsequent lawsuit.
Periodic written progress reports are an effective means of doc-
umenting the sequence of events on any project. These written
reports are especially important on projects which are suspended
or restarted, or which have changes which occur during the life
of the project.
Another element of good communication is timely response.
Letters, shop drawings and other submittals should be processed
and responded to in a reasonable time period.
Many of the claims against consultants result from activities
during construction phase services. To minimize these claims, it is
important to utilize carefully developed contract documents. The
Engineers' Joint Contract Documents Committee (EJCDC) has
developed a set of carefully integrated contract documents. Use
of these contract documents allows a consultant to take advan-
tage of the latest recommendations of the professional societies
based on their continuing research and standardization.
Disputes and misunderstandings occur on all projects of signif-
icant size. All too often, minor differences of opinion burgeon
into demands, and those demands escalate into formal claims.
Without appropriate management, the filling of claims marks the
beginning of lengthy, expensive litigation that culminates in arbi-
tration or courtroom confrontation. It is extremely difficult to
develop a rational strategy for concluding a dispute once en-
meshed in legal proceedings. The dispute quickly becomes mag-
nified to the point that the parties fail to consider alternatives
that would benefit them. Claims and counterclaims often are
significantly inflated above their realistic value; the parties may
fail to consider litigation costs and the time value of money in
their evaluations; and sources of compensation are frequently
overlooked. By structuring construction contracts so that they
can be readily administered and are flexible enough to address
potential claims through administrative procedures, claims fre-
quency can be minimized. Careful attention to the following sub-
jects will minimize the potential for future claims:
• Contract modification procedures and dispute resolution mech-
anisms
• Risk-sharing provisions
• Project constructibility and bidability
• Value engineering review
Effective dispute management requires an aggressive, innova-
tive approach. Every effort should be made to resolve disputes at
the earliest practical date.
INDEMNIFICATION
It is generally conceded that consultants are not responsible for
the existence of most Superfund sites, therefore, the consultant
should not incur excessive liability when providing engineering
services for cleanup of the sites. Based on this premise, a mech-
anism is needed to protect the consultant. As discussed previous-
ly, insurance frequently is not a viable source of protection. An
alternate approach which is being increasingly used is indemnif-
ication.
A committee of the American Consulting Engineers Council
has developed language which can be used to provide indemnifi-
cation to the consultant. The language suggested is as follows:
"For services involving or relating to hazardous waste
elements of the Agreement, Owner shall indemnify, de-
fend and hold harmless Engineer and its consultants,
agents and employees from and against all claims, dam-
ages, and employees from and against all claims, damages,
losses and expenses, direct and indirect, or consequential
damages, including but not limited to fees and charges of
attorneys and court and arbitration costs, arising out of or
resulting from the performance of the work by Engineer,
or claims against Engineer arising from the work of others,
related to hazardous waste."
"The above indemnification provision extends to claims
against Engineer which arise out of, are related to, or are
based upon, the dispersal, discharge, escape, release or
saturation of smoke, vapors, soot, fumes, acids, alkalis,
toxic chemicals, liquids, gases or any other material, irri-
tant, contaminant or pollutant in or into the atmosphere,
or on, onto, upon, in or into the surface or subsurface
(a) soil, (b) water or watercourses, (c) objects, or (d) any
tangible or intangible matter, whether sudden or not."
Legal assistance is important when drafting indemnification
language for a contract. An indemnification clause should be
carefully drafted and should recognize the bargaining position of
all parties to the contract. Numerous states have enacted some
form of anti-indemnification statute. Indemnification tends to be
inconsistent with the general premise that everyone should be
responsible for his own errors. Thus, before the indemnification
approach can be used successfully, it must be compatible with
applicable state statutes. At least one state, New Jersey, provides
by statute indemnification for consultants performing hazardous
waste cleanup services.
CERCLA legislation was pending at the time this paper was
being written. Therefore, no discussion is given to the contents of
the legislation or the impact on consultants' services for super-
fund work. Adequate protection in the legislation for consultants
providing services at superfund sites is critical. If the legislation
authorizes a pass through of indemnification to state led super-
fund work, it will open the door to a substantial portion of the
work being administered by stale agencies.
Federal clients other than the U.S. EPA which manage haz-
50 INDEMNIFICATION & COSTS
-------
ardous waste work include the Corps of Engineers, Department
of Energy and Department of Defense. These agencies have direc-
tives and policies which cover the approach to indemnification.
The adequacy of the indemnification provided must be analyzed
carefully by the consultant on a case by case basis.
CONCLUSIONS
Consultant liability concerns must be resolved to assure the
participation of technically qualified and financially responsible
consultants in the hazardous waste cleanup program. The current
insurance situation provides no coverage for pollution related
claims. The insurance available is characterized by higher deduc-
tible amounts, lower upper limits on coverage and higher insur-
ance costs.
Answers to the liability concerns are found in expanding qual-
ity control programs, obtaining indemnification from the client
and passing tort reform legislation. Expanding the consultant
quality control programs is essential since a majority of suits
against consultants historically have been due to alleged design
error. An important element in quality control is assuring that
personnel utilized on hazardous waste projects have strong cre-
dentials in their areas of expertise.
The availability and costs of insurance for consultants involved
in hazardous waste work are interrelated with tort reform legis-
lation. As state and Federal legislation is enacted, it is likely that
insurance will be available from a larger number of firms, prob-
ably at more reasonable costs. However, tort reform is not ex-
pected to result in the availability of coverage against pollution
related claims in the near future. In the absence of insurance for
pollution related claims, indemnification by the client is neces-
sary. The exact form of the indemnification will vary according
to the type of client and nature of the work involved.
The absence of either insurance coverage or protection through
indemnification will result in an unsatisfactory situation. Under
these circumstances, the only consultants available to provide the
services are firms willing to run the risk of bankruptcy when liti-
gation occurs.
The firms willing to risk bankruptcy are not available in ade-
quate numbers to provide needed services. In addition, a bank-
rupt firm offers no protection against financial loss to its former
clients.
All of the solutions discussed will play a role in overcoming the
liability problem. In the short term, indemnification must be a
major factor in the consultant's ability to provide service. As
tort reform becomes a reality and as the insurance industry re-
turns to a more normal state, it is expected that increased cover-
age eventually will be available to consultants.
INDEMNIFICATION & COSTS 51
-------
Federal Indemnification of Superfund Program
Response Action Contractors
Robert Mason
U.S. Environmental Protection Agency
Office of Waste Programs Enforcement
Washington, D.C.
Mark F. Johnson
Edward Yang, Ph.D.
Planning Research Corporation
McLean, Va.
ABSTRACT
The U.S. EPA currently is evaluating approaches to assist the
Property & Casualty insurance industry's ability to provide pros-
pective pollution liability insurance. The 1986 market for pollution
liability insurance is minimal, is hampered by continuing capacity
problems and is not expected to fulfill the present or future liability
insurance needs of the hazardous waste management industry. Five
Federal environmental statutes require those subject to the statutory
law to furnish evidence of financial responsibility, thus a viable
commercial liability insurance market is important to the achieve-
ment of Federal environmental policy goals.
Public policy decision-making regarding the use of commercial
liability insurance in the hazardous waste management industry
has become increasingly difficult in recent years because of rapid
and unpredictable expansions and contractions in the supply, terms
and conditions, and price of commercial liability insurance. The
Congress, concerned about a withdrawal of response action con-
tractors (RACs) from the Superfund program incorporated
language into the existing CERCLA reauthorization bill authorizing
the U.S. EPA to provide limited interim indemnification against
liabilities for negligence to RACs on a discretionary basis. This
paper briefly reviews the proposed U.S. EPA Superfund response
action contractor indemnification program.
INTRODUCTION
One of the cornerstones of the Superfund Program under
CERCLA has been the availability of qualified response action con-
tractors (RACs). These contractors have developed into a unique
industry specializing in addressing the nation's hazardous waste
sites. Because of the hazardous contaminants managed at these
sites and the uncertainty surrounding new response technologies,
RACs face potential liabilities if a site releases new hazards during
or after the remedial response. In the past, these contractors have
relied primarily on a combination of commercial liability insurance
and government indemnification to reasonably offset the liability
risks (e.g., third-party suite) from Superfund program cleanup
activities. However, the recent retreat of the commercial property
and casualty (P&C) insurance industry from the pollution liability
insurance market is threatening RAC withdrawal from the hazard-
ous waste site business (1).
With the expected heavy load of site responses for the forth-
coming years, any reduction in the capacity of the RAC industry
may adversely affect the Superfund Program (2). Table 1 and
Figure 1 summarize the potential RAC pollution liability issue.
Table 1 lists the potential damages and the liability bases upon
which suits seeking redress could be brought against RACs. Figure
1 displays the potential RAC pollution liability risk as a function
of several key component parts consisting of the probability of
occurrence, potential damages and the legal environment.
Table 1.
Potential CERCLA Response AcUon Damages
and Bases for Liability
Liability Bases
A. Comnoa Law
1. Negligence
2. Strict Liability
3. Trespass
4. Nuisance
& Sutatory Uabffity
1. Suit
1 Federal
Damages
I. Compen»tor> Damage*
A. Special Damage*
I. Medical Care Expenses
2. Loss of Income
3. Medical Monitoring
Tesls
4. Risk of Latent Disease
- Carcinogenic
- Mutagenic
- Tcraiogenic
B. General Damages
1. Pain and Suffering
2. Mental Anguish
3. Loss of Consortium
4. Disfigurement
C Properly Damages
I. Loss of Properly Values
2. Relocation Expenses
Temporary Housing
Permanent Housing
3 Procurement of Alter-
nate Water Supply
4. Business Interruption/
Extra Expenses
5. Other Economic Values
II. Punltlvr Damages
III. Environmental/Natural
Resource Damages
IV. Environmental Right Damages
Cleanup Costs
- State, Local, County, etc.
VI. Other Damages
VII. Defense Costs
The Congress, concerned about a withdrawal of the RACs from
the Superfund program, incorporated language into the existing
CERCLA reauthorization bill authorizing the U.S. EPA to pro-
vide limited interim indemnification against liabilities for negligence
to RACs on a discretionary basis. U.S. EPA indemnification wiB
apply to all U.S. EPA approved RACs and their subcontractors
working under the Superfund cleanup program for the U.S. EPA,
another Federal agency, states involved in cleanups of CERCLA
sites, and potentially responsible parties (PRP). These provisions,
if enacted, will represent an important development in the distri-
bution of the risks from discharges of hazardous substances
managed at Superfund sites. In essence, the Federal government
will be stepping temporarily into the private sector as a surrogate
52 INDEMNIFICATION & COSTS
-------
Probability
of
Occurrence
Potential
Damages
Legal
Environment
RAC
Liability
Function
En g ineerin ft/Construction
1. Investigation u*«i«h crr.^.
2, Remedy Selection "^ Effecls
3. Design Transport/Fate & Exposure to
4. Construction Populations
5. Maintenance
6. Monitoring
i
Health Environment
<
State
Properly & Defense &
Income Losses Cleanup Costs
t
Federal Local
r
Potential Response Action Contractor Liability - flProbability
of Occurrence»Damai;es*Legal EnvironmenuDefense Costs)
Figure 1
Response Action Contractor Liability Function
insurer. This direct interim substitution or supplement of com-
mercial insurance will significantly ensure the nation's technical
ability to remedy uncontrolled hazardous waste sites.
PROBLEM SUMMARY
During the first 5 yrs of the Superfund Program, RACs who par-
ticipated in the program by working for the U.S. EPA were pro-
vided with Federal indemnification in excess of a $1 million liability
insurance policy or self-insurance layer (for third-party liability and
cleanup costs) except in cases that involved gross negligence. During
the course of the recent CERCLA reauthorization debate, it became
apparent to the U.S. EPA, Congress, and RACs that the commercial
liability insurance industry was no longer willing to provide afford-
able and adequate liability insurance coverage to RACs involved
in the Superfund cleanup program.
The insurance industry, suffering from record underwriting losses
and capacity problems during 1984 and 1985, withdrew from many
high risk liability insurance lines (e.g. pollution liability). The
Property & Casualty (P&C) insurance industry argued that it could
no longer underwrite pollution liability insurance because of (1)
a lack of capacity and reinsurance support, (2) a lack of loss data,
(3) no existing uniform risk analysis methods (4) expanding tort
liability in the U.S. legal system, (5) real and anticipated losses and
(6) a general societal perception that hazardous waste cannot be
safely managed.
During the CERCLA reauthorization debate, RACs argued that
without viable risk transfer mechanisms, such as commercial lia-
bility insurance or government indemnification, they would be
forced to withdraw from the Superfund cleanup program, rather
than subject their limited corporate assets to potential Superfund
liabilities. RACs viewed the existing Federal government indemni-
fication program under Superfund to be inadequate because; (1)
there is an absence of statutory authority to indemnify RACs, (2)
there is no source of funds identified by statute, (3) it may violate
the Anti-Deficiency Act, and (4) it did not apply to all parties (e.g.,
RACs working for other Federal agencies, States or responsible
parties). The RAC community introduced several legislative propo-
sals to address the lack of adequate risk transfer mechanisms for
Superfund related RAC liability including: (1) statutes of limita-
tions/repose, (2) liability caps, (1) a negligence liability standard
for RAC and (4) mandatory government indemnification for all
RAC Superfund cleanup program liability.
The U.S. EPA and Congress realized that a lack of viable risk
transfer mechanisms for the RAC community might cause prudent,
qualified RACs to withdraw from the Superfund cleanup program
and could lead to delayed and reduced quality Superfund cleanups
in the future, if the hazardous waste management industry, such
as the Superfund RACs, pulls out of the hazardous waste cleanup
market, the cost of the shortage in pollution liability insurance
coverage ultimately is borne by the public. The Superfund program
is especially vulnerable to this withdrawal because a delay in
response action or use of unqualified contractors may pose direct
risks to public health and the environment. The U.S. EPA, after
extensive study of the P&C insurance industry, realized that
adequate RAC commercial liability insurance might not be available
on a stable basis for several years. In an effort to solve this problem,
the U.S. EPA supported legislative proposals that would provide
the U.S. EPA with interim discretionary indemnification of RACs
to reasonably offset liability risk associated with Superfund
cleanups. The U.S. EPA also supported legislative proposals that
sought a pre-emptive and uniform negligence liability standard for
RACs and a modified version of the Risk Retention Act (which
allows RACs to provide themselves with self-insurance through risk
pooling and captives).
Both Superfund bills contained provisions for the U.S. EPA to
indemnify RACs. After considerable debate, Congress agreed in
conference to adopt the language into the final CERCLA
reauthorization bill authorizing the U.S. EPA to provide limited
interim indemnification against liabilities for negligence to RACs
on a discretionary basis. In addition, Congress agreed in conference
to adopt a Federal non-pre-emptive negligence standard for RACs
and a modified version of the Risk Retention Act.
RATIONAL FOR FEDERAL GOVERNMENT
INDEMNIFICATION
The primary thrust underlying the Government's indemnification
of Superfund RACs is the goal of pushing ahead with Superfund
cleanups. This goal assumes the availability of high-quality cleanup
contractors for all phases of the program (i.e., site investigation,
risk assessment, response selection/design and construction). Pro-
viding the U.S. EPA with the authority to provide discretionary in-
demnification to RACs essentially calls for the Agency to become
a surrogate insurer until the P&C insurance market condition
changes favorably. Federal government intervention in the
marketplace for RAC liability insurance is justified for several public
policy reasons including (1) discretionary indemnification is an in-
terim vehicle designed to keep the Superfund cleanup program
operative until the private sector insurance market is able or willing
to provide adequate and affordable liability insurance for RACs
working in the Superfund program, (2) discretionary indemnifi-
cation of RACs does not create a permanent Federally intrusive
insurance program, which could discourage the private sector in-
surance industry from participating prospectively, (3) discretionary
indemnification provides RACs with performance incentives by not
providing for all liability expenses (i.e., deductibles and limits) and
(4) discretionary indemnification is consistent with Administration
concerns and Congressional intent.
In addition, such temporary Federal government intervention is
justified given the inherent problems in the P&C insurance
marketplace including: (1) the P&C underwriting cycle has tradi-
tionally produced periods of either excess demand or excess supply
for insurance coverage, (2) state regulation of the insurance
mechanism discourages new firms from coming into the
marketplace during periods of low P&C insurance availability and
(3) the P&C insurance industry has high entrance barriers in terms
of capital requirements, thus limiting the number of firms that can
meet the capital reserve requirements. These aspects constrain the
P&C industry from responding quickly to demand for insurance
during periods of low insurance availability and excess demand.
The renewed surge in the use of offshore captives has shown that
only when exempted from state regulation and when backed by
numerous large firms can new insurance entities emerge in response
INDEMNIFICATION & COSTS 53
-------
to excess demand. A modified version of the Risk Retention Act
(contained in both the House and Senate Bills and adopted in con-
ference), allows for expedited and efficient formation of self-
insurance through risk pooling by hazardous waste industry
members (including RACs). Risk pooling should provide additional
risk transfer mechanisms for RACs Superfund cleanup liability in
the absence of adequate and affordable commercial liability
insurance.
Instead of waiting for the insurance industry to realign itself to
RAC demand for liability insurance, the U.S. EPA and Congress
determined that the cost of slowing down the Superfund Cleanup
program warrants temporary intervention into the insurance
marketplace (through RAC indemnification) and long-term pro-
motion of alternative risk transfer mechanisms (through captives,
self-insurance pools, etc.).
HOW THE US. EPA WILL USE ITS DISCRETIONARY
INDEMNIFICATION AUTHORITY
If enacted, the U.S. EPA RAC indemnification program will
apply to all U.S. EPA-approved RACs and their subcontractors
working under the Superfund cleanup program for the U.S. EPA,
another Federal Agency, the States and PRPs. As mandated by Con-
gress, the U.S. EPA will offer indemnification to a RAC working
in the Superfund program only if two conditions are met. First,
the RAC must make every reasonable attempt to obtain adequate
liability insurance and/or responsible party indemnification. The
U.S. EPA will require any RAC receiving indemnification to con-
tinue to attempt to obtain insurance and/or responsible party
indemnification throughout the life of the contract. If liability in-
surance and/or responsible party indemnification is made available
during the life of the RAC contract, the U.S. EPA will have the
discretion to require that such insurance and/or responsible party
indemnification be obtained and may reduce the terms of the indem-
nification agreement accordingly. Second, the U.S. EPA must deter-
mine that liability insurance or responsible party indemnification
is not available, is not adequate to offset the RACs liability risk
and/or is not reasonably priced. If these two conditions are met,
the U.S. EPA will offer indemnification only as a supplement or
substitute for insurance or responsible party indemnification, in-
cluding limits and deductibles, and only for liability related to
releases of hazardous substances resulting from RAC Superfund
cleanup activities. Figure 2 summarizes the proposed sharing of
CERCLA response action pollution liability risk between RACs,
P&C insurers, responsible parties and the U.S. EPA.
U.S. EPA indemnification of RACs, including all specified terms
and conditions, will be offered to the lead (prime) RAC. The in-
demnification will be made available by the lead RAC to any U.S.
EPA authorized subcontractors with which the lead RAC may team.
The U.S. EPA will retain the right to control the defense and set-
Type of Kef lit ence
Dollart
of Lou
RAC Graf
Negligence
Unlimited
RAC
Liability
Iriik
retention)
Layeri of Litbimy in Caiei of RAC
Negligence
Potential RAC Unlimited
Liability Layer
EPA Indemnification Layer
(Subject to Limit! and Deductible
Level!)
Reipooiible Parly Liability Layer
(e.g.. Indemnity Agreement!)
Available Commercial Property It
Catualty Iniurance Layer
RAC Deductible Layer
Riik Handling
Mecbanlim
Riik Retention
Riik Trwrfer
Rlik Retention
Figure 2
Potential RAC Liability Layers
tlements of a claim covered by RAC indemnification. Since the
source of indemnification funding is now identified by statute, it
will allow the U.S. EPA to establish comprehensive processing pro-
cedures for the reimbursement of defense costs and claims. The
limits of indemnification will be determined based on what is
sufficient to offset RAC liability risk, and not by what is or has
been available in the commercial liability insurance market.
U.S. EPA TASK FORCE INDEMNIFICATION OBJECTIVES
At the request of the U.S. EPA Assistant Administrator for the
Office of Solid Waste and Emergency Response, a Task Force was
established to develop policy on indemnification of response action
contractors working in the Superfund Program. The U.S. EPA Task
Force research will form the basis for the development of the U.S.
EPA RAC indemnification policy. The two major goals of the Task
Force's research are: (1) to develop appropriate interim, US. EPA
RAC indemnification terms and conditions and (2) to develop a
RAC underwriting approach which will provide the P&C insurance
industry with the technical assistance necessary to foster prospec-
tive commercial RAC liability insurance coverage.
The first major goal of the Task Force, to develop an interim
Government RAC indemnification program, is vital to prevent the
breakdown of the nation's Superfund hazardous waste site cleanup
program because of the current lack of commercial liability in-
surance coverages for RACs active in Superfund site remedial work.
The second major goal of the Task Force, to develop a RAC under-
writing approach that the insurance industry can use to underwrite
RAC liability insurance coverages, is vital to the creation of a com-
mercial liability insurance market for RACs in the future. By
providing the P&C insurance industry with this technical assistance,
the U.S. EPA anticipates that the insurance industry in the future
will replace Government indemnification of RACs. In doing its
research, the Task Force anticipates considerable input from the
P&C insurance industry. Furthermore, the Task Force intends that
the P&C insurance industry will be the ultimate user of the U.S.
EPA RAC underwriting approach that is developed and used by
the U.S. EPA.
The U.S. EPA Task Force on the Indemnification of Response
Action Contractors faces complex issues and difficult decisions in
reaching its objectives. The Task Force objectives are:
• Determine the limits of US EPA indemnification (above deducti-
bles, commercial liability insurance and responsible party indem-
nification agreement layers) that are reasonable to offset prob-
able and catastrophic risk RACs participating in the Superfund
cleanup program.
• Identify the exposures/risks that RACs are subject to when parti-
cipating in the Superfund cleanup program; identify the various
legal sources of RACs potential liability losses, which result from
a threatened release of any hazardous substance or pollutant or
contaminant if such release arises out of response action activities;
identify the potential liabilities for which RACs may be held
legally liable when participating in the Superfund cleanup
program.
• Determine the extent to which qualified/prudent RACs will avoid
entering into Superfund cleanup contracts with the U.S. EPA if
the limits of U.S. EPA indemnification, as determined by the Task
Force, are set below what RACs deem to be an acceptable level
of risk transfer; identify how the limits of US. EPA indemni-
fication, as determined by the Task Force, affect the capacity and
quality level of RACs available to perform Superfund cleanup
activities; identify how the determined limits affect the US EPAs
ability to meet legislatively mandated EPA Superfund action
schedules.
• Establish the underwriting criteria the the US. EPA will use to
determine whether a RAC is an acceptable risk for U.S EPA to
indemnify; determine the terms and conditions of the indemni-
fication contracts that the U.S. EPA will offer to RACs partici-
pating in the Superfund cleanup program.
• Determine the appropriate regulatory and/or administrative
mechanisms necessary to implement and monitor the progress
of the U.S. EPA's indemnification of RACS.
54 INDEMNIFICATION & COSTS
-------
The U.S. EPA indemnification of RACs will be governed by the
terms and conditions determined by the U.S. EPA Task Force, as
appropriate. The basis for selecting the appropriate terms and con-
ditions is the assessment of RAC liability risks. The U.S. EPA Task
Force will identify and estimate these risks. The baseline for deter-
mining what are adequate RAC indemnification terms and condi-
tions is to establish the upper limits of indemnification that
reasonably offset RAC probable risk (e.g., defense costs) and
catastrophic risk (e.g., third-party liability suits). While maintain-
ing incentives for adequate RAC performance (e.g., deductibles).
Limits will be based on what is determined to be adequate to off-
set RACs liability risk associated with Superfund cleanups, thus
assuring the continuance of the Superfund cleanup program.
The first step in establishing RAC indemnification limits will be
to identify the scope of RACs Superfund cleanup activities (e.g.,
the types of work and disciplines involved) for RACs seeking indem-
nification. Potential loss exposures then will be identified from the
scope of RAC Superfund cleanup activities.
The second step is to measure in dollar terms the potential lia-
bility risks that RACs face when participating in the Superfund
cleanup program, related to the identified scope of work and
disciplines involved. The estimated frequency and severity of RAC
liability claims resulting from Superfund cleanups will be calculated
by incorporating the following information: applicable historical
loss data, technical and scientific data, spread of risk (e.g., poten-
tially liable parties, role of the RAC, etc.), professional judgement
and probability of risk.
The third step will be to create loss forecasts (based on the above
information) that attempt to estimate the maximum possible loss
and the maximum probable loss that RACs could face as a result
of a given scope of Superfund cleanup activities. Once a range of
potential liability losses is statistically estimated and/or established
through professional judgement, the U.S. EPA and RACs.
In establishing RAC indemnification limits, the U.S. EPA will
rely on input from the RAC community (e.g. risk managers, chief
executive officers, etc.), professional insurance actuaries and under-
writers, the legal community, the academic community and U.S.
EPA contract specialists, technicians, scientists and legal counsel.
A survey of RAC liability risks will provide the initial informa-
tion/data basis for this determination. Figure 3 delineates the com-
ponents the U.S. EPA Task Force will incorporate into its policy
analysis to determine the appropriate terms and conditions of the
proposed RAC indemnification program. Once the assessment of
RAC risks is made, the U.S. EPA Task Force will develop alternative
indemnification limits and deductible levels in conjunction with
professional actuaries. The Task Force will incorporate all the above
information into the development of terms and conditions of the
U.S. EPA RAC indemnification mechanism.
RAC Risk
Survey
Probability Tree
Analysis
Potential Damages
Analysis
Assessment of RAC
Liability
Legal Analysis
(Including Potential
Defense Cost Analysis)
Indemnification/
Deductible Analysis
Inter-Industry
Risk Comparison
Development of RAC
Indemnification
Terms & Conditions
Figure 3
Components for Determination of Proposed U.S. EPA RAC
Indemnification Program Terms and Conditions
plementation of such a U.S. EPA indemnification program poses
difficulties in the areas of constructing coverage limitations, deter-
mining deductible levels and other RAC indemnification terms and
conditions.
CONCLUSION
The U.S. EPA faces a challenge in developing and administering
an indemnification program for the Superfund program's response
action contractors, so that cleanup of the nation's hazardous waste
sites will not be interrupted. Although such a program currently
is justified for several public policy reasons, Congressional intent
is to avoid establishing the Federal government's long-term presence
as a surrogate insurance mechanism for the RAC community. Im-
REFERENCES
1. Yang, E. and Johnson, M., "Responding to Hazardous Waste Sites:
Sharing the Response Risks" Journal of Hazardous Materials (in press)
2. Lucero, G, Director, U.S. EPA Office of Waste programs Enforcement,
testimony before Subcommittee on Water Resources, U.S. House of
Representatives, July 24, 1985.
INDEMNIFICATION & COSTS 55
-------
A Model for Apportioning
The Cost of Closure of a Waste Site
Robert T. Denbo, Sr.
R.T. Denbo, Sr., Inc.
Baton Rouge, Louisiana
Dhamo S. Dhamotharan
Woodward-Clyde Consultants
Baton Rouge, Louisiana
ABSTRACT
An approach has been developed for apportioning the costs of
closure (and post-closure) of a hazardous waste site among the
identified potentially responsible parties. The development of this
methodology is principally in response to a need generated by the
Federal Superfund Program for cleaning up hazardous sites as
provided in CERCLA. The developed model utilizes predicted or
actual costs of closure as the primary mechanism for apportion-
ment. Consequently the developed system apportions the cost of
eliminating or minimizing any potential threats to the environ-
ment from the wastes at a given site since that is the function of
the closure plan. As currently developed, the model is not de-
signed for use in apportioning the cost of any damages to human
health or the environment.
The model is based on the contribution of a waste to the cost of
closure rather than on other waste characteristics that have
resulted in a hazardous classification. While such characteristics
as carcinogenicity, oral or dermal toxicity, corrosivity, etc. are
important in establishing the urgency of closure, these char-
acteristics may have little bearing on the cost of the closure
method to be implemented. The principal thrust of apportion-
ment using this model is cost rather than characteristics. Total
cost of closure is intended to include all costs associated with
closure such as costs of the remedial investigation and feasibility
studies and post-closure monitoring.
A model that can equitably apportion total cost of closure will
be of value in prompt settlement of Superfund cases. Quick settle-
ment will benefit all involved parties if expensive and lengthy
litigation can be avoided. It is believed that the model described
herein can be a step in the direction of expediting settlements.
INTRODUCTION
Cleaning up the nation's hazardous waste sites will require an
immense effort. On June 1, 1986, approximately 800 sites had
been named on the U.S. EPA's National Priority Listing which
includes sites deemed to be eligible for cleanup funds under the
Superfund program. The U.S. EPA estimates that the ultimate
list will include 2,500 sites and that the cost of cleanup will
amount to $22.7 billion. The U.S. EPA's inventory of all hazar-
dous waste sites that eventually will require closure currently lists
approximately 19,000 sites.
The Office of Technology Assessment (OTA) has estimated
that the number of priority sites will be much higher than
estimated by the U.S. EPA and will ultimately increase to 10,000.
Cleanup costs for these sites are estimated to amount to $100
billion. The total cost of cleanup will be staggering regardless of
who is correct.
Superfund legislation does not provide a method to apportion
the cost of closure in situations where more than one waste
generator has been identified. As a result, apportioning these
costs under Superfund has been left to the litigants and the courts.
The usual plaintiff in a court action is the federal government and
its position is that liability under Superfund is "joint and
several." Under this concept, any single responsible party maybe
held liable for the entire amount of the costs of closure where
liability is indivisible, or costs may be apportioned equally among
a number of liable parties. This concept has appeal for the federal
government because of its simplicity. The federal government can
attempt to recover all closure costs from a select number of defen-
dants. This simplifies the government's job. The task of bringing
action against other responsible parties not named in the suit is
left to the select number of defendants named in the federal
government suit.
To date, courts have not established a clear cut policy regarding
apportionment. Some courts have held that a defendant who
wishes to avoid apportionment of costs by the "joint and several"
concept has the responsibility to demonstrate that costs can be ap-
portioned fairly by some other procedure. No such demonstration
has been made to the satisfaction of a court.
However, it is obvious that apportionment of costs by the
"joint and several" concept is not equitable. It consequently
follows that an equitable apportionment method acceptable to the
involved parties would be highly desirable.
There is a real temptation on the part of many potentially
responsible parties to accept almost any method of apportion-
ment to "get it over with." However, closure of some sites has
shown that the actual cost of site closure can far exceed initial
estimates. In addition, unexpected developments such as unan-
ticipated contamination of adjacent areas can increase the cost of
closure as much as an order of magnitude. An equitable appor-
tionment will prevent the resulting cost burden from being borne
by parties whose wastes may have contributed only slightly to
unanticipated closure cost increases.
The magnitude of costs of closure and the lack of adequate cost
apportionment methods have complicated litigation and
discouraged out-of-court settlements. Such settlements are con-
sidered highly desirable by all parties for a multitude of reasons
including litigation costs and the excessive time required in litiga-
tion.
CURRENTLY AVAILABLE MODELS
The U.S. EPA is considering a number of models to assist in
settlement of Superfund closures. One model was developed to
estimate the total cost of closure and all future expenditures in-
volved in closure. Another was developed to estimate the cost of
litigation. Yet another was developed to assess the ability of the
56 INDEMNIFICATION & COSTS
-------
potentially responsible parties to pay—a so-called "deep pocket"
model. However, at this writing, a technically sound method of
apportioning the cost of closure among the potentially responsi-
ble parties has not, to the authors' knowledge, been forthcoming.
Some models have been proposed which allocate costs prin-
cipally on the basis of waste quantity and waste characteristics,
such as lexicological properties, biological properties and other
chemical and physical properties. While such properties may be
pertinent to the potential of a waste to do harm to human health
and/or to the environment and establishment of the urgency of
closure, these properties are not relevant to actual costs incurred
in closure in many cases.
THE PROPOSED APPROACH
An ideal method of apportioning costs would be one that
realistically assesses the contribution of each company's waste to
the cost required to eliminate or minimize the combined threats of
all wastes present in the site to be closed. Since the closure plan,
by definition, is designed to eliminate or minimize such threats,
equitable apportionment of the cost of closure should accomplish
this objective. The apportionment model described in this paper is
called the DDA model. It is based on a realistic assessment of the
impact of each waste on the total cost of cleanup of a particular
site containing a particular mixture of wastes. The apportionment
of costs among the involved parties using the DDA model is
customized for a specific closure plan required for a specific site.
Closure of a waste site is a complex operation. Consequently,
apportionment of costs of closure is not a simple matter. The ra-
tionale for the proposed apportionment method is described
below.
Each waste present at a site to be closed may contribute dif-
ferently to costs involved in each of the three phases of a closure
plan:
• Surface Closure—elimination of potential threats to human
health and the environment from waste constituents im-
pounded or stored at the surface
• Shallow Subsurface Closure—elimination of such threats re-
sulting from leakage into adjacent soil and the resultant soil
contamination
• Ground-water Remediation—elimination of such threats from
contamination of groundwater
The separate cost of each phase usually can be readily deter-
mined. Using unit costs for each phase, the cost contribution of
each waste to each phase is then determined. The contribution of
each waste to the overall total closure cost is the accumulation of
the costs associated with each phase.
As shown later in this paper, this approach provides an appor-
tionment that is customized for particular wastes at a particular
site.
APPORTIONMENT EXAMPLE
The example presented in the following section shows the
general method of calculation and also how site conditions alone
may have a dramatic effect on both the total cost of closure and
the apportionment of the closure costs. In the example, it is
assumed that three companies each produce a specific and dif-
ferent waste. It is further assumed that identical quantities of each
of these wastes have been deposited at three sites—each with sig-
nificantly different soil and subsurface conditions.
Discussion of Apportionment Results
Table 1 shows that each company generated identical quantities
of waste. Each waste was hazardous and heavier than water.
Company A's waste has the lowest tendency to move through
soils and is very low in solubility in water. Company C's waste has
the greatest tendency to move through soils and is more soluble in
water than the wastes generated by the other two companies.
Company B's waste is intermediate in both mobility and water
solubility between wastes generated by Companies A and C.
Company C's waste has strong solvent properties and tends to
form a solution of the other two wastes. As a result, Company
C's waste tends to increase the rate of movement of the other two
wastes through soils.
Table 1
Wastes Deposited—Quantities and Type at Example Site
Co.
Qty. of
Waste
(tons)
Type of Waste
1000
B 1000
1000
Hazardous, high density, viscous aromatic oil
containing benzo(a)pyrene, very low mobility
in soil and very low solubility in water
Hazardous, high density, less viscous aro-
matic oil containing creosote, moderate
mobility in soil and slightly soluble in water
Hazardous, high density, low viscosity liquid
waste containing chlorinated hydrocarbons,
very mobile in soils and more soluble in water
Table 2
Site Soil and Subsurface Characteristics at Example Site
Site
1
2
3
Soil Permeability
Extremely low stiff clay
Moderate-silty clay
High-sandy clay
Clay
Depth
(ft)
40
20
0
Depth to
First Aquifer
(ft)
300 +
300 +
30
Table 2 shows the variation in soil and subsurface characteris-
tics at each of the three sites. The sites range from a stiff, low
permeability clay with the first aquifer at a depth of 300 ft at Site
Table 3
Closure Plan Approach and Unit Costs at Example Site
Procedure
Units
$/Unit
Surface Closure
• Treat all free water in impoundment
(use activated carbon) and discharge K gal
• Excavate all wastes tons
• Incinerate all wastes (off-site) tons
• Backfill and vegetate yd3
Shallow Subsurface Closure
* Excavate contaminated soil yd3
• Vault contaminated soil (as required)
on-site yd3
• Backfill yd3
Groundwater Remediation
• Recover contaminated groundwater;
treat and discharge K gal
50
10
400
(includes
transportation)
15
10
40
10
100
INDEMNIFICATION & COSTS 57
-------
1 to a sandy cjay of high permeability and the first aquifer at a
depth of 30 ft at Site 3.
Closure Plan
Table 3 presents the closure plan approach and unit costs for
the steps required for closure of all three sites. The steps in each
phase are summarized briefly below.
Surface Closure
• All contaminated free water in the impoundments will be treated
and discharged under a temporary permit
• All impounded wastes will be excavated and transported for
incineration off-site
• The emptied impoundment will be backfilled with clean soil.
Topsoil will be added and the surface vegetated; handling of
contaminated soil is discussed in the next section.
Shallow Subsurface Closure
• Contaminated soil will be excavated to an acceptable depth de-
pendent on "how clean is clean" criteria
• Contaminated soil will be solidified as required and stored in
an RCRA vault on the site
• Clean soil will be used for backfill
Groundwater Remediation
• Recovery wells will be installed as required
• Contaminated groundwater will be pumped from the aquifer as
determined by "how clean is clean" criteria and treated using
activated carbon prior to discharge under a state or federal
permit
Apportionment of Costs
Closure costs can be expressed on an average unit cost basis for
each of the steps in closure. These units costs then can be used in
the determination of the contribution of each waste to the cost of
closure for each step.
Tables 4, 5 and 6 present the information obtained from the
assessment of each of the three sites in the example. It is also
shown that contaminated free water is present in the impound-
ments at each of the three sites.
As shown in Table 4, there was no contamination of soil or
groundwater at Site 1 resulting from any waste since the soil is a
very stiff, low permeability clay.
Table 5 indicates that at Site 2 there was soil contamination
from wastes from Companies B and C but none from Company
A's waste. The soil at Site 2 was of relatively moderate
permeability.
However, Table 6 shows that both soil contamination and
groundwater contamination occurred at Site 3 since soil was
relatively permeable and the first usable aquifer was quite
shallow.
Table 4
Site 1 — Information from Site Assessment
Table 5
Site 2 — Information from Site Assessment
Co.
Wute
Typ«
Qty. of
Waste (toot)
Qty. of
Contaminated
Soil (ydl)
Qly. of
Conlanjlaaled
Groandwaler
A WA i.ooo o
B WB 980 1,000
C We 800 8.000
Quantity of Contaminated Free Water in Impoundment — 100 K gal
Table 6
Site 3 — Information from Site Assessment
0
0
0
Co.
A
B
C
Wute
Type
WB
wc
Qty. of
Wade (low)
980
900
700
Qty. of
CoaUBlulcd
SoH (jrdJ)
1.000
2.000
10.000
Qly. of
CoaUmiuled
Groudwalcr
(KcaO
100
1.000
10.000
Quantity of Contaminated Free Water in Impoundment — 100 K gal
FREE WATEfl
MO CONTAUINATCO a OH. OH GROUND WATCH
aiTI 1
FREE WATER
BOUNDARY OF
CONTAMINATED SOIL
NO CONTAHHIATCD O.ROUND WATER
atri a
FREE WATER
BOUNDARY OF
CONTAMINATED SOIL
BOUNDARY OF CONTAMINATED OROUND WATER
Co.
A
B
C
Waste
Type
wA
WB
wc
Qly. of
Wute (tons)
1,000
1,000
1,000
Qly. of
Contaminated
Soil (yd3)
0
0
0
Qty. of
Contaminated
Groundwaler
(Kgal)
0
0
0
Quantity of Contaminated Free Water In Impoundment — 100 K gal
Figure 1
Results of Remedial Investigation
Fig. 1 presents a schematic indicating qualitatively surface
water, soil and groundwater contamination at each of the three
sites.
Tables 7, 8 and 9 present the calculations of the share of closure
costs for each company at each site. The total cost of closure and
58 INDEMNIFICATION & COSTS
-------
the pro rata share of each company as calculated using the pro-
posed method is summarized below:
Table 9
Site 3 — Proration of Closure Costs
Company
A
B
C
Totals
Site 1
Share
K$ °7o
427 33.33
427 33.33
427 33.33
1,281 100.00
K$
426
478
826
1,730
Site 2
Share
%
24.6
27.60
48.80
100.00
Site 3
Share
K$
487
615
1,995
3,097
15.70
19.90
64.40
100.00
Quantity
SURFACE CLOSURE
o Treat Contaminated Water 100
o Excavate Waitel 2,310
0 Incinerate Watte 2,310
o Baddlll and Vegetate 2,3SO
SHALLOW SUBSURFACE CLOSURE
o Excavate Contaminated Soil 13,000
and beddlll
0 Vault Contaminated Soil 13,000
Colt,
Units SAInit
Kgal 30
yd' 10
T tOO
yd» 13
yd' 20
yd' to
Portion of Coat to Indicated
ComDOny. KS
2
10
392
13
20
to
D
2
10
360
13
to
10
2
10
2SO
13
200
too
Overall
Cloeure
Total. KS
30
1,032
39
260
320
NOTE: Costs associated with the RI/FS, post-closure monitoring and all other
similar costs were not included in this example. Such costs should be included in total
closure costs and should be apportioned on the same basis as calculated for closure
costs shown above.
Table 7
Site 1 — Proration of Closure Costs
Portion of Coat to Mhate*
.T. KS
SURFACE CLOSURE
0
0
0
0
Treat Contaminated
Surface Water
A
e
C
Subtotal!
Excavate Watte!
A
B
C
Subtotal!
Incinerate Wai te
A
B
C
Subtotal!
Bactilll and Vegetate
A
B
C
Subtotal!
Quantity
33
33
33
100
1,000
1,000
1.000
3,000
1,000
1,000
1.000
3,000
1,000
1,000
1.000
3,000
"""»
KeaJ
Kjel
ICpl
yd'
yd'
yd'
T
T
T
#\
#1
yd'
S/Unlt
30
»
30
10
10
10
too
too
too
13
13
13
_*_
2
.
-
2
10
-
10
too
.
_
too
1]
_
-
13
. "
.
2
_,••_.
2
.
10
_-_
10
.
too
400
.
1J
-
15
C
.
.
2
2
-
.
-L9_
10
.
.
too
too
.
.
_L2_
13
Total. KS
2
2
2
«
10
10
10
30
too
too
too
1,200
13
13
13
t3
SHALLOW SUBSURFACE CLOSURE
N/A
GROUND WATER REMEDIATION
N/A
Total!
% Share
127
33.3
t27
33.3
t27
33.3
1,211
100
Table 8
Site 2 — Proration of Closure Costs
Quantity Unlta
SURFACE CLOSURE
0 Treat Contaminated Water 100 K gal
0 Excavate Waite 2,710
o Incinerate Waite
A 1,000
B 910
c goo
Subtotal! 2, 780
o Backfill and Vegetate 2, 710
SHALLOW SUBSURFACE CLOSURE
o Excavate Contaminated Soil (and baddlll)
A 0
B 1,000
C 1.000
Subtotal! 9,000
o Vault Contaminated Soil
A 0
B 1,000
C 1.000
Subtotal! 9,000
GROUND WATER REMEDIATION
N/A
Total!
W Share
*'
T
T
T
yd'
$
si
_SC»
30
10
too
too
too
13
20
20
20
to
to
to
Portion ol Coat to Indicated
Comronr. KS
A t, t
1
10
too
.
-
too
It
-
__- _
-
_
-
t26
2t.6
2
10
.
392
-
392
It
20
-
20
to
-
to
t7l
27.6
2
10
.
»
3JO_
320
It
;
160_
160
_
J2S_
320
126
• 7.1
Overall
Cbeuro
Total. KS
6
30
too
392
_329
1,112
•2
20
160
in
0
to
320
360
1,730
100
GROUND WATER REMEDIATION
Subtotal!
Total!
100
1,000
10.000
11,000
are
Kjal
Kgal
Kgal
100
100
100
10
10
• 17
13.7
100
100
613
19.9
1.000
1,000
1,993
6t.l
10
100
1.000
1,110
3,097
100
As indicated, variations in only site conditions resulted in an in-
crease in closure costs from $1,28IK at Site 1 to $3,097K at Site 3.
Company shares ranged from a 33.33% for each company at Site
1 to 15.7% for Company A, 19.9% for Company B and 64.4%
for Company C at Site 3.
The simplified case shows only three companies and three
wastes involved at the disposal sites. However, when many com-
panies are involved and each produces several wastes, this ap-
proach involves numerous calculations. The model handles the
arithmetic manipulations required.
APPROACH WHEN MANY
PARTIES ARE INVOLVED
How can the DDA model approach be used in apportioning
closure costs when a large number of parties (each of which may
have produced several wastes) is involved in a site? Since involve-
ment of that many companies is not unusual, the answer to this
question is of great significance. At many sites, 50 or more parties
may be involved. In most cases, when a large number of parties
deposited wastes at an inactive site, one or both of two conditions
may exist. Many of the parties may have deposited only small
amounts of waste and/or some of the parties may not have been
identified. For parties known to have deposited a small quantity
of wastes of moderate toxicity, say 1% or less, at the site in ques-
tion, it is recommended that the actual percentage of the waste
deposited be used as a basis for apportionment of the total cost of
closure. (However, this approach should be reconsidered if the
small quantities of waste are particularly mobile in soils and
found to contribute to contamination of soils and groundwater
far in excess of the percentage of the overall quantity of wastes at
the site.) The model can then be used to apportion the remaining
cost of closure among those parties whose shares exceed 1 %. The
pro rata shares determined on this basis would apply to the entire
cost of closure including costs associated with wastes from parties
not identified.
There may be cases in which the presence of one waste (or a
small number of wastes) may dictate the disposal technique that
will be required for all of the wastes present in a site. For example,
if even a small amount of PCBs was deposited by one party and
mixed with other wastes at a site, the presence of this particularly
hazardous waste probably would result in the mixture of wastes at
the site coming under the U.S. EPA requirements for handling
PCBs and/or PCB-contaminated waste. Conventional landfilling
(vaulting) may have been an acceptable disposal technique for all
other wastes at the site, but contamiantion by PCBs may have
resulted in all of the wastes being classified as PCB-contaminated
INDEMNIFICATION & COSTS 59
-------
with the result that these wastes may require incineration in a
facility permitted for such wastes. Some of the wastes with lower
PCB contamination may require vaulting in one of the few land-
fills permitted by the U.S. EPA to handle such wastes. The
presence of only a small amount of PCBs should thus result in a
dramatic increase in the cost of closure of the site. The question
of how to apportion closure costs in such a case becomes very im-
portant. Such questions would arise as:
• Should the party who deposited the PCB waste bear the entire
increased cost of closure that results from the presence of PCBs?
• What part of the increased cost should the other parties bear?
One school of thought would suggest that the party that
deposited the PCBs was in the best position to know what prob-
lems were being caused and consequently that party should bear
the entire added cost of closure resulting from the presence of
PCBs.
Another school of thought may suggest that all parties should
share "equally" based on the apportionment method used in the
total cost of closure on the basis that those parties whose waste
did not contain PCBs should have been aware of the risk that they
were incurring by depositing waste at the site in question. This at-
titude employs the so-called "cesspool" effect—or guilt by
association.
Perhaps, a better solution than either of these positions would
be an intermediate course. This approach would involve estimates
of the cost of closure if each waste had been deposited separately.
The sum of these costs could be determined as the cost of separate
closure. This sum could be deducted from the actual cost of
closure which would include the effect of the presence of PCBs.
The difference would represent the added cost resulting from the
presence of PCBs. This added cost could be split in half, with one
half being borne by the party who deposited the PCB waste and
the other one half apportioned among the remaining parties on
the same basis as used in the DDA model approach. This ap-
proach would penalize the generator of the hazardous waste that
controls the method of closure more than the other parties who
deposited waste at the site.
INFORMATION REQUESTED FOR
APPORTIONMENT
To employ the DDA model approach, one should use as much
of the following type of information as is available:
• The quantity and properties of each of the wastes that each
company had delivered to the site
• The closure plan expressed in such a way that unit costs can be
expressed for:
—surface closure
—any required shallow subsurface closure
—any required groundwater remediation
This type of information is continually being improved from in-
itial preliminary evaluation through final closure and consequent-
ly would be available at a number of stages of development of
closure. Some of the stages at which estimates would be available
are:
• Completion of preliminary site assessment
• Completion of Remedial Investigation and Feasibility Study
(RI/FS)
• Final design for closure
• Completion of closure
Since apportionment of costs is essentially driven by the cost of
closure, estimates of apportionment can be made at any point in
the development of closure at which cost estimate is available.
Generally, a preliminary apportionment made at an early stage in
closure development is suggested to provide guidance for the
potential responsible parties regarding their approximate shares
of the cost. However, the most accurate apporlionment is based
on the final actual cost since the best information is available at
that point. The proposed procedure is dynamic and can provide
the most realistic apportionment upon actual closure even if some
unanticipated development arises during closure.
A number of suggestions regarding site closure and handling of
the model are presented in Table 10.
Table 10
Suggestion* for Handling Site Closure
And Proratlon of Closure Cacti
• Form a Steering Group to administer closure
• Set up a fund to cover initial costs including the Work Plan, RI/FS
and design of closure
• Obtain agreement on a method for prorating closure (and post-
closure) costs
• Develop first pass proration based on initially available data
• Use the agreed upon procedure to prorate the costs of closure
Note: The names of (he companies should not be divulged to the modeler when sup-
plying waste quantities and properties. A coding system should be used to reduce
subjectivity.
The formation of a Steering Committee composed of repre-
sentatives of the potentially responsible parties is a generally ac-
cepted first step. It would be desirable for this group to provide a
fund for the expenses to be incurred in development of the Work
Plan, the RI/FS and closure and post-closure design. These costs
would later be included in the final apportionment of costs. It
would be desirable to obtain agreement on a method of appor-
tioning closure costs at ah early point. A first pass apportionment
should be developed on the basis of data available at an early
stage for review by the potentially responsible parties. Agreement
should be reached on the stage in closure development at which
final apportionment will be based. Objectivity can be enhanced
by using code names when supplying information about the
wastes that were generated by the various companies to the
modelers.
CONCLUSIONS
Apportionment of the costs of closure and post-closure is a ma-
jor problem with for federal and state agencies and the potentially
responsible parties. One of the primary objectives of all involved
parties is expeditious settlement to avoid delays and costs
associated with prolonged litigation. It is believed that the method
described herein will provide an equitable basis for apportion-
ment and thus expedite closure settlements.
60 INDEMNIFICATION & COSTS
-------
Considerations of Discounting Techniques Applied
To Superfund Site Remediation
Thomas J. Buechler, P.E.
Keith A. Boyd, P.E.
Black & Veatch
Kansas City, Missouri
ABSTRACT
Selection of a remedial action alternative for Superfund sites
involves consideration of several factors including technical and
socioeconomic factors that are often difficult to compare. The
remedial action decision-maker is forced to compare the eco-
nomic costs for varying technologies and differing cash flow
requirements. To facilitate the cost comparison, a discounting
technique—the net present worth concept—is used to produce a
single cost value.
While the net present worth concept simplifies the economic
comparison of alternatives, it fails to fully reflect the costs asso-
ciated with each alternative. Its shortcomings include failure to
fully differentiate the impacts of inflation and project risk. The
use of a sensitivity analysis helps reduce the economic uncertainty
in selecting an alternative. However, the decision-maker must be
aware of the limitations of the net present worth technique if
sound economic decisions are to be made.
This paper explores the application of the net present worth
technique to Superfund site remediation decisions. The assump-
tions necessary for use of the technique are examined as are its
shortcomings in addressing inflation and differing levels of pro-
ject risk. The sensitivity analysis also is discussed and explained
bv use of an example.
INTRODUCTION
The selection of a remedial alternative on sites being managed
under CERCLA is based on several decision criteria including
engineering reliability, implementability and constructability; en-
vironmental and public health impacts; institutional issues; and
project cost. These factors collectively serve as input to the pro-
cess of selecting a recommended or preferred alternative for re-
mediation of a particular site. The total number of sites that can
be remediated is directly related to the number of sites entering
the Superfund system, as well as to the balance in the trust fund
established by Superfund to finance cleanups. Clearly, the al-
ternatives that meet the U.S. EPA policy objectives and result in
the least financial expenditure are preferred.
While technologies that treat or destroy hazardous wastes and
substances are developing due to market demand pressures, the
cost of implementing these technologies is often difficult to esti-
mate. Part of this difficulty stems from uncertainty with respect
to economies of scale, competitor behavior, regulatory compli-
ance and operating efficiencies realized through full-sca'e applica-
tions. Additional uncertainty can be caused by lengthy imple-
mentation times between selection of a remedy and the actual
application of the technology. The decision-maker faces the addi-
tional challenge in comparing alternatives offering different waste
management strategies such as land disposal and waste inciner-
ation. It is difficult to choose between land disposal options and
a more expensive destruction option such as incineration, when
concerns over future releases and resultant liabilities are factored
into the decision process.
Discounting is the conventional method of comparing eco-
nomic costs of alternatives with differing cash flow requirements.
This method allows the decision-maker to evaluate all alterna-
tives in terms of a single, base year cost. Discounting techniques
are quite effective in such applications, but use and interpreta-
tion discounting models can be misleading, particularly if the de-
cision-maker is not aware of the method's limitations.
DISCOUNTING TECHNIQUES
Capital budgeting decisions are based on a number of tech-
niques with the payback method, the net present worth method
and the internal rate of return , employ the discounting concept.
The discounting concept is based on the realization of the value
of a dollar with respect to time. Simply stated, the premise is that
the value of $1 to be received or expended at some time in the
future is worth less than the value of $1 today. The difference in
value depends on the interest rate and the length of time the
amount of money could be invested to yield or provide $1 in the
future. For example, $1 spent 1 yr from now is worth less than
$1 today because it is discounted by the amount of interest it
would earn in the intervening year. In this sense, the interest rate
is referred to as the discount rate, usually stated as a per annum
percentage.
The term "present worth" is an amount at some beginning or
base time that is equivalent to a particular schedule of receipts or
disbursements under consideration. If only disbursements or ex-
penditures are considered, the term can be expressed best as
"present worth cost.'" By discounting all future costs to a com-
mon year base, the costs of various alternatives can be compared
on the basis of a single figure. This figure represents the resources
in today's dollars needed to meet the future expenditures asso-
ciated with a particular alternative.
The net present worth technique uses the discounting concept.
Cash receipts in future years are discounted to a base year. Simi-
larly, the costs to build, operate and maintain a proposed pro-
ject are calculated and discounted to the same base year. The net
present worth is calculated as follows:
Net Present Worth = (Present Worth of - (Present Worth of (1)
cash receipts) cash expenditures)
Businesses prefer alternatives with the highest net present worth
as they maximize the value of the firm. If an alternative involves
only expenditures, the net present worth will be negative. In this
INDEMNIFICATION & COSTS 61
-------
case, the least negative alternative represents the preferred altern-
ative.
Net present worth can be expressed as the equation (2):
NPW =
n
E
Ft
- 1
(2)
where:
NPW = net present worth
F = net cash flow in year t
k = discount rate
I = initial investment
n = number of years from time t = 0.
As indicated by the above equation, the information needed
to calculate the net present worth includes the cash expenditures
and receipts for each year of the life of the alternative, the as-
sumed discount rate, the initial investment required and the ex-
pected number of years in the life of each alternative.
The internal rate of return method involves calculation of the
interest or discount rate required to make the net present worth
of an alternative equal to zero. Instead of comparing net present
worth values, this method compares the interest rates of return.
Decisions which maximize the value of the firm require selection
of the highest rate of return. While this method is widely used
by industry in making a selection among several alternatives com-
peting for limited available investment funds, it is not appropriate
to Superfund site decisions because of the difficulty associated
with quantifying the economic benefits of site remediation. This
method is also tedious; it requires trial and error solutions to de-
termine the one interest rate which makes the net present worth
equal to zero.
CURRENT APPLICATION TO
SUPERFUND SITES
U.S. EPA guidance documents3-4 specify the use of present
worth analysis to compare remedial alternatives. The develop-
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for predicting the differences in the relative escalation of costs
associated with the project. Inflation usually is measured by the
Consumer Price Index (CPI), although other, more discriminat-
ing indices are available. The CPI is a composite index that in-
cludes the costs for housing, food, energy, health services, etc.
Subgroups of the CPI, particularly energy prices, are likely to
have a greater impact on cash flow projections associated with
remedial actions than the cost of housing. Recent history pro-
vides strong evidence that projecting the inflation or deflation of
energy prices contains a large factor of uncertainty. Therefore,
it is likely that energy-intensive alternatives, such as "pump and
treat" or incineration, can significantly underestimate or over-
estimate the costs in future years.
The error that arises from failure to include inflation in cash
flow estimates is compounded with time as long as inflation is
positive. This results in understated distant cash flows tending to
favor alternatives which involve long-term treatment or active
migration prevention systems and long-term storage.
Inflationary expectations of investors are an intrinsic compon-
ent of the discount rate, for investors will invest funds at differing
interest rates and for differing periods of time based in part on
their guess about inflation. The discount rate, therefore, includes
an allowance for inflation. The inflation expectation rates for
businesses and for the government will be different, as they oper-
ate in different economic arenas. Use of the 10% discount factor
appears more appropriate to the business sector than for the
U.S. EPA, which understates the present worth of distant year
expenditures for government financed projects.
Risk Premiums
In practical terms, the discount rate consists of three com-
ponents: a risk free value of money, an inflationary expectation
adjustment and a risk premium. The last component is a func-
tion of the amount of risk associated with a given alternative.
The current practice of utilizing a constant discount rate implies
all alternatives are subject to the same degree of risk. Yet, it is
arguable whether the alternatives that involve destruction of haz-
ardous substances are preferable to alternatives that are based on
storing wastes for an indefinite period, because the destruction
alternative eliminates the long-term threat of future release of
the substance into the environment.
Thus, the long-term risk to the public health and the environ-
ment associated with destruction technologies is usually consid-
ered lower than for storage alternatives. Similarly, the risk asso-
ciated with innovative and developing technologies not proven in
the field is considered higher than the risk associated with proven
technologies.
The discount rate can be calculated as follows:5
(1+K) = (1+Rf) (1+Ei) (1+Rp) (3)
where:
K = discount rate
Rf = risk free value of money
Ei = premium for inflationary expectations
Rp = risk premium
Holding the risk premium component of the discount rate con-
stant for all alternatives fails to acknowledge the differing risk
levels associated with the technologies. While establishing a risk
premium for each management alternative could be cumbersome
and subject to rapid change, a small number of risk classes could
be set up, with a different risk premium being assigned to each
class.6 This would give the remedial site project manager a clear-
er economic indicator on the alternatives being evaluated.
EXAMPLE OF NET PRESENT WORTH
ANALYSIS
To further explore the net present worth method, consider the
following example. One decision to be made on a Superfund site
addresses remediation of the threat to public health posed by con-
taminated groundwater. Two technologies have been declared
feasible in the pre-screening process. One technology consists of
containment of the contamination by means of a slurry wall sys-
tem. The second technology involves removing the contaminated
groundwater, treatment at an on-site water treatment facility and
re-injection of the effluent back into the contaminated aquifer.
The risk associated with this latter alternative is considered
higher because it is uncertain whether sufficient quantities of
contaminants can be removed to lower the public health threat
to a level where no further remedial action is required. Model-
ing of the contaminated aquifer indicates that pumping and treat-
ing will be required for at least 50 yr to achieve a concentration
approaching the one additional cancer in 100,000 (10 ~5) risk
level.
The alternatives and their costs are given in Tables 1 and 2.
These tables present the installation costs in 1986 dollars for each
alternative as well as the annual operation and maintenance
costs. The net present worth calculations are shown using a dis-
count rate of 10% and no allowance for inflation.
As shown in the tables, the net present worth cost of the
"pump and treat" alternative is $4.02 million, and the net pres-
ent worth cost of the slurry wall is $8.07 million, more than twice
the cost of the pump and treat alternative. How would the costs
differ if a lower discount rate were used and inflation were fac-
tored into the equation?
To answer this question, a sensitivity analysis was performed.
The discount rate was changed from 10% to 4%, and a 2% in-
flation adjustment was factored into the projected costs. Table 3
summarizes the results of the analysis. The sensitivity of the dis-
count rate is shown by comparing the net present worth values at
10% and 4%. The pump and treat alternative is not as econom-
ically attractive at the lower discount rate because of the larger
annual expenditures for operation and maintenance.
Because of these higher costs, the impact of inflation was
thought to be critical. Therefore, the annual expenditures were
Table 1
Containment by Slurry Wall
Description of Technology:
Construct slurry wall around contaminated aquifer. To control hy-
draulic gradients, install media (gravel) drains around top of wall and re-
move small quantity of water. Treat water and discharge. Install cap over
site to reduce inflation.
Annual operation and Maintenance:
Maintain and replace cap as needed. Maintain drains and treat ground-
water removed.
Installation Cost:
$7,510,100 (1986 dollars)
Annual Costs:
Cap Maintenance $ 8,000
Drain Maintenance 2,500
Treatment Costs 23,900
Site Monitoring 25,000
$59,400
Net Present Worth:
(30 yr, 10% discount rate)
NPW = (-annual costs) (present worth factor)-Installation Costs
NPW = (-59400) (9.427) - 7,710,000
NPW = -$8,070,064
INDEMNIFICATION & COSTS 63
-------
inflated by 2%/yr for both alternatives, and the net present worth
values were calculated. As demonstrated by the 2% inflation and
4% discount rate scenario, the pump and treat alternative is ap-
proaching the cost for the slurry wall alternative, reflecting the
impact of inflation on the operation and maintenance costs.
Larger inflation rates would drive the cost of the pump and treat
alternative at a higher rate than the slurry wall alternative. Clear-
ly, the cost comparisons are quite sensitive to inflation.
Table 2
Pump and Treat
Description of Technology:
Install extraction wells, pumps and header system. Remove contam-
inated water and treat in on-site treatment facility. Inject effluent into
aquifer to facilitate removal of contaminants.
Annual Operation and Maintenance:
Maintain and replace wells, pumps and header system. Purchase chem-
icals for water treatment and maintain treatment facility. Electricity for
well pumps, labor, to operate equipment.
Installation Cost:
$1,485,550
Annual Costs:
Extraction $111,600
Injection 127,200
Treatment 103,300
Monitoring 49,000
$391,100
Net Present Worth:
(30 yr, 10% discount rate)
NPW = (- annual costs) (present worth factor) - installation cosi
NPW = (-391100) (9.427)-1485550
NPW = -$4,021,413
CONCLUSION
The net present worth discounting technique is valuable in
facilitating the cost comparisons of remedial actions by virtue of
its ability to combine future expenditures with installation costi.
It is relatively simple to use and calculate. Yet such simplifica-
tion of calculations can lead to faulty decisions if the limitations
of the technique are ignored.
The limitations include failure to fully consider the impacts of
inflation and different project risk levels. Alternatives that in-
clude large annual operating and maintenance costs are affected
by inflation to a much higher degree than capital-intensive al-
ternatives. Alternatives associated with long-term cash flows
(e.g., 20 to 30 yr) and times of positive inflation are undervalued.
The project risk for each alternative is difficult to quantify and
is assumed equal in present applications. Alternatives that destroy
hazardous substances contain a lesser risk for additional releases
than landfill or capping alternatives. Recent feasibility studies in-
dicate that the costs of land filling or capping alternatives are sig-
nificantly lower than destruction alternatives such as incinera-
tion. Theoretically, this difference in cost can be accounted for by
assigning different risk premiums to different technologies. This
change would further facilitate the economic comparisons on
Superfund sites.
Developing the risk premiums for each technology would re-
quire input from waste management experts, engineers, scien-
tists and perhaps even those members of the public most affected
by the remediation effort. Such value judgments are not conduc-
ive to quick consensus, but nevertheless could serve the Super-
fund remediation process by facilitating decision-making and gen-
erating more meaningful discussion of the relative merits of each
alternative.
The French philosopher Paul Valery said that a fact poorly
observed is more treacherous than faulty reasoning. By being
aware of the net present worth limitations and assumptions, the
remedial decision-maker can make better decisions.
Table 3
Sensitivity Analysis
Net Present Worth (1986 dollars)
0% inflation 2% Inflation
10% 4% 10% 4%
SlurryWall -8.07 -8.54 -8.19 -8.85
Pumpand -4.02 -5.98 -4.46 -7.34
Treat
REFERENCES
1. Canada, J.R. and White. J.A., Capital Decision Analysis For Man-
agement and Engineering. Prentice-Hall, Englewood Cliffs, NJ, 1980.
2. Weston. J.F. and Brigham, E.G., Managerial Finance, The Dryden
Press, Hinsdale, IL. 1978.
3. U.S. EPA, "Guidance on Feasibility Studies Under CERCLA,"
Washington. DC. 1985.
4. CH2M-HUI, "REM/FIT Cost Estimating Guide," July 1985.
5. Hodder. J.E. and Riggs, H.E., "Pitfalls in Evaluating Risky
Projects," Harvard Business Review, Jan.-Feb. 1985.
6. McGuigan, J.R. and Moyer, R.C., Managerial Economics, 2nd ed.,
West Publishing Company, St. Paul. MN, 1979.
64 INDEMNIFICATION & COSTS
-------
The Application of Quantitative Risk Assessment
To Assist in Evaluating Remedial Action Alternatives
Lawrence J. Partridge, Sc.D.
Camp Dresser & McKee Inc.
Boston, Massachusetts
ABSTRACT
The application of a quantitative risk assessment is employed to
evaluate the cost-effectiveness of remedial action alternatives. A
four-stage cancer model was employed to evaluate the risk of in-
gesting groundwater contaminated with four carcinogenic
chemicals to the exposed population. Three remedial actions were
evaluated (including no-action) to assess the level of risk reduc-
tion following implementation. Baseline risk was evaluated as the
equivalent of 14 excess cancers over the 30-year exposure period
studied during the analysis.
Under the implementation of the remedial alternatives, the
baseline risk was reduced by 58% using a groundwater treatment
system and 72% using a containment wall and groundwater treat-
ment system. The net present value costs for each system are
calculated, and the marginal costs for implementation are com-
pared with the incremental reduction in cancer risk. The results
suggest that the marginal costs for implementing the more costly
alternative should be examined carefully in terms of expenditures
per number of incidents avoided.
INTRODUCTION
The application of quantitative risk assessment has become an
increasingly important component in the evaluation of remedial
alternatives at abandoned hazardous waste disposal sites. This
type of analysis is employed initially to identify the baseline level
of risk associated with both current site conditions and the no-
action alternative. A subsequent analysis then is completed to
evaluate the reduction in the baseline risk that is anticipated
following the implementation of remedial alternatives. This
reduction in public health risk which might be measured, for ex-
ample, in terms of reduction in the expected number of cancer in-
cidents, then can be employed to assess the effectiveness of the
proposed remedial alternatives and examine the costs incurred to
reduce risk to targeted lower levels.
A previous study2 presented an approach to employ quan-
titative risk assessment to evaluate remedial alternatives. This ap-
proach was based upon extrapolations from work completed by
the U.S. EPA Carcinogen Assessment Group (CAG) and served
as a basis to develop a risk assessment methodology. This current
analysis is an extension of the initial study and incorporates
several additional concepts into the analysis procedure.
The first modification of the U.S. EPA work relates to the
evaluation of age-specific considerations with respect to the in-
cidence of risk in a known population. The second modification
incorporated into the analysis is the evaluation of dose attenua-
tion following the implementation of a remedial action program.
The incorporation of these two factors into the analysis provides
the ability to more realistically evaluate potential public health
impacts upon a specific population (of known demographics) ex-
posed to contaminants migrating from hazardous waste disposal
sites.
APPROACH
The risk assessment approach used in this analysis was reported
previously and is summarized in Fig. 1. The critical elements in
the risk assessment include the identification of those hazardous
substances which have migrated from the site (target con-
taminants) and impacted (via ingestion of groundwater) upon a
known receptor population (population at risk). Also, it is impor-
tant to establish the dose-response relationship for human ex-
Indantify Tone Contaminants
Prt i«nt m Groundwattr
and Surtaca Watar
_L
Spteify Individual Watia
Malanala for Inclunon in
Pathways and Fata Analysis
_L
|0«t«rmint F»U of
Individual w»tta
Calculata Exposura Lavals
(or Each Population
1
CalcuUltd Butllna Bilk
for No-Action Allarnallv*
-
Jdantity
Populatlonl at
Risk
SpaclfyOos»fl*spon
flalatlonshlps
Figure 1
Risk Assessment Methodology
HEALTH ASSESSMENT 65
-------
posure to the target contaminants and to evaluate dose reduction
in response to the implementation of a specific remedial alter-
native.
Target Contaminants
This analysis examines the risk to an exposed population
associated with the ingestion of drinking water containing low-
dose levels of 'four hazardous substances which have been
evaluated for carcinogenic potency by the U.S. EPA CAG. The
CAG evaluation of carcinogenic potency is based upon applica-
tion of a linear multi-stage model (others are available) to
evaluate cancer risk associated with a continuous lifetime ex-
posure (70 years) to a carcinogen via ingestion of 2 1 of water per
day contaminated with the carcinogenic substances. A typical
dose response curve is shown in Fig. 2; a linearized curve (dashed
line) which is considerably more conservative in the low dose
region being evaluated in this analysis also is shown for com-
parison.
1.00
Probability
ol Response
si Dose D Over
Background
1.00
Dose
Figure 2
Dose Response Curve
The four chemicals identified in drinking water included
benzene, trichloroethylene, chloroform and 1,2-dichloroethane.
Benzene and trichloroethylene were measured at 20 jig/1, respec-
tively, and chloroform and 1,2-dichloroethylene were measured
at 10 pg/1.
Population at Risk
The population at risk is represented by a hypothetical age-
specific grouping having characteristics which are based upon the
1980 U.S. Census. The exposed population consists of nine in-
dividual groups which are stratified on the basis of age. The
predominant grouping in terms of numbers is the 15-24 age group
with 18.6% of the total populations of 100,000.
The population does have a dynamic quality; the birth rate is
assumed to be 20 per 1,000, the death rate is calculated at 850 per
100,000 and no migration from the study population is allowed.
Remedial Alternatives
There are three remedial action alternatives considered for this
particular program, including the option for no-action. The
technology-based remedial alternatives employ the concepts of
either treating the contaminated groundwater or both containing
and treating the groundwater.
The groundwater treatment option includes the provision for
locating two clusters of extraction wells on-site and off-site. The
extracted groundwater is treated to remove volatile organics and
metals prior to discharge to a POTW. The on-site wells will be
operational for 30 years while the off-site wells will be sequential-
ly phased out of service after 10, 20 and 30 years.
The groundwater containment and treatment option not only
relies upon groundwater extraction and treatment, but also
employs a containment wall to control the migration of con-
tamination from the source. This system will operate for 30 yean
but will reduce the time required to achieve a steady state of
groundwater contamination such that the dose of contaminant
received by the exposed population is less than that associated
with the groundwater treatment option.
It is assumed that the relationship between the relative levels of
groundwater contamination and the time following implementa-
tion of the individual remedial alternatives is represented by a
series of step functions. Each technology-based remedial alter-
native will achieve a similar level of residual groundwater con-
tamination following 30 years of operation. However, this level of
control is achieved in a shorter time-frame when the containment
wall is employed in combination with a groundwater extraction
and treatment system.
Risk Model
The analysis for cancer risk associated with the ingestion of
contaminated drinking water utilizes the application of a multi-
stage model. This type of model is based upon the assumption
that the degeneration of a ceU to the malignant state is represented
by a series of sequential processes or stages. The individual
number of stages is variable but usually ranges from three to six.
Transfer from one stage to another can be in response to dost
dependent initiating or activating events, while transfers from
other stages may occur as random events.
This following analysis of cancer risk is based upon the recent
efforts of Crump and Howe,' who present an approach which
enables the analyst to incorporate consideration of factors such as
short-term exposures, time-dependent dosage patterns, age at the
onset of exposure and the relationship between dose and the
various stages of the cancer process into the assessment of cancer
risk.
This analysis evaluates the cumulative lifetime cancer risk to a
person exposed to a constant dose of a carcinogen beginning atj
age S, and continuing for a duration of (S2-S|). The lifetime risk
must also reflect consideration for the number of stages which
comprise the multi-stage process and the individual stage(s) which
is/are identified as being dose dependent. The number of in-
dividual stages which represent the cell transformation process is
identified as K; the dose dependent stage is identified as r.
Given that the initial stage in the carcinogenic process is dose
related (as might be the case with an initiator as opposed to a pro-
moter), then the risk H(t) is given as:
H(t)-(d)(c)
where:
H(t) equals the cumulative cancer incidence due to exposure
t is the individual's present age
d is the dose level
c is a constant term based upon carcinogenic potency
k represents the number of stages prescribed by the car-
cinogenic process
S, is the age of the exposed population at the onset of exposure
$2 is the age upon termination of exposure
c is a constant which represents carcinogenic potency
0
k
(t-s1)k - (t-s2)k
t
-------
The cumulative incidence of cancer associated with a short-
term environmental exposure can be related to the CAG estimate
(lifetime exposure evaluation) at the same dose level to evaluate
the fraction of lifetime cancer risk which manifests itself during
the short-term episode. This expected level of risk (F) measured as
a fraction of the lifetime risk estimate can be calculated using
Equation 2:
F =
70
t=Sl
(t-s/
70
t=o
70
t=s2
(t-s/
(t-s2)k
(2)
Equation 2 was utilized to generate a family of curves shown in
Fig. 3 which describe the relative risk to individuals exposed to an
environmental carcinogen; the curve shows the risk variation as a
function of both age at onset of exposure and the duration of the
exposure episode. The carcinogenic process was assumed to be a
four-stage process with the first stage being dose dependent and
subsequent transformations represented by the random events.
This family of age-specific curves establishes the relationship be-
tween the years of exposure to an environmental carcinogen
(OO) and the percentage of the lifetime risk (as per CAG) which
is associated with this limited duration exposure. These curves
i.o
.001
.0001
.00001
/ I
4 nag* moat)
only lint lligt ao» -tltlM
10 20 30 40
Y««r» of «ipo«ur»
50
Figure 3
Cancer Risks vs. Years of Exposure by Age at Exposure Onset
provide a mechanism to calculate the age-specific exposure risk
estimate utilized in this analysis.
A review of these curves clearly indicates (based upon the
assumed multi-stage model) that for a given level and duration of
exposure, the younger population groupings incur a significantly
larger percentage of their lifetime cancer risk relative to older
segments of the population. Generally, a majority of a typical
population's risk of environmental carcinogenesis is manifested in
the 35 and younger age group.
CALCULATION OF RISK
The risk calculation for the exposed population addresses three
specific conditions with respect to remedial alternatives. Under
the no-action alternative, the estimate for cancer risk is simply the
population at risk multiplied by the cancer risk estimated by the
CAG procedures. Carcinogenic effects are assumed to be additive
for purposes of this analysis. The results of this calculation in-
dicate that the expected number of lifetime cancer incidents is ap-
proximately 14 over 70 years if no action is taken to remediate the
off-site migration of hazardous wastes. This initial estimate for
risk under the no-action alternative provides a baseline estimate
from which to measure how effectively individual remedial alter-
natives reduce health risk.
The first remedial alternative considered for implementation in-
volves the installation of a containment wall with provisions to
isolate the contaminant sources and simultaneously pump con-
taminated groundwater from the aquifer system and treat the
water prior to discharge. A profile for the levels of contaminant
reduction based upon laboratory treatability studies and com-
puter modeling of the aquifer system indicates that contaminant
levels in the groundwater are represented by a step function with
existing levels remaining relatively constant for 10 years and then
decreasing to approximately 10% of the current levels. The levels
remain unchanged for the 20 years that the system remains opera-
tional. The initial 10-year period that the system does not impact
upon groundwater quality reflects the fact that contamination has
spread beyond the influence of the remedial system; a period of
time must elapse before any improvements are noted in ground-
water quality.
The implementation of this remedial alternative results in the
reduction in the expected level of risk. Based upon the application
of the multi-stage model and the assumed population distribu-
tion, it is estimated that the expected number of cancer incidents
would be approximately 3. This number must be adjusted for the
risk which is incurred following the 30-year remedial action pro-
gram, recognizing that there will be residual contamination in the
groundwater. It was estimated that this residual risk was
equivalent to approximately 1 additional incident of cancer. This
value must be added to the projected 30-year risk associated with
the groundwater containment and treatment system which results
in a final risk level (expected number of cancer events) equivalent
to approximately 4.
A similar analysis was conducted for the second remedial alter-
native based upon groundwater extraction and treatment but with
no provision for the containment wall. This remedial option, like
the previous alternative, had no influence upon groundwater
quality for the first 10 years following installation. The improve-
ment in groundwater quality was modeled as a step-function with
contaminant levels decreasing to 70% of the initial level during
years 10-20 following installation of the system and to 40% of the
initial value during years 20-30. The final level of contamination
was evaluated at 10% of the initial value and the improvement
continued for years 40-70.
The risk associated with this alternative was equivalent to 5.0
expected incidents of cancer associated with the 30-year operation
HEALTH ASSESSMENT 67
-------
of the system. To this, one must add the additional risk associated
with the residual groundwater contamination for years 30-70. The
addition of this incremental risk resulted in a total expected risk
for the groundwater treatment alternative of approximately 6.0
incidents of cancer.
COMPARISON OF REMEDIAL ALTERNATIVES
AND EXAMINATION OF COST-EFFECTIVENESS
The individual risk associated with the three remedial action
alternatives can be compared to assess the cost-effectiveness of
options which employ the application of technology to reduce the
expected incidence of cancer associated with the implementation
of remedial action technology. The baseline level of risk
associated with the no-action alternative was estimated at 14
cancer events in the exposed population based upon application
of the U.S. EPA CAG estimates for carcinogen potency. The
residual risks following implementation of the groundwater con-
inment and treatment system or the groundwater containment
system were 4 and 6, respectively. Therefore, the number of
predicted cancer events avoided following implementation of the
two technology-based remedial alternatives are 8 and 10.
This information about public health risk should be utilized to
assist decision-makers regarding selection of appropriate remedial
alternatives. However, there is no consensus among the scientific
community regarding the approach which should be employed to
formally introduce risk-based calculations into the identification
of cost-effective remedial action programs.
A critical element in introducing risk-based calculations into
decisions regarding public health risk centers upon our inability or
unwillingness to place a numerical value upon mortality and mor-
bidity. There is an entire field of literature based upon alternative
procedures to monetarize mortality and morbidity, but there is no
consensus regarding the most appropriate method to develop
such measures.
The approach used in this analysis examining how monetary
considerations for public health risk can be factored into selecting
remedial alternatives is shown in Fig. 4. Here, a plot is made of
the number of public health incidents avoided versus the present
value cost of remedial action at a hazardous waste site where
groundwater contamination poses a public health threat. Overlain
on the plot is a series of curves representing the costs associated
with each avoided incident. Depending upon the severity of the
incident (mortality vs morbidity, for example) the associated costs
of avoidance were represented as ranging from $100,000 to
•Range of Com Per Incident Avoided
Figure 4
Present Worth of Dollars Expended for Remedial Action (Millions)
$2,000,000 per event.
The analysis proceeds by examining the relationship between
the number of incidents avoided and the costs to implement the
specific technology which leads to the avoided events. The
number of incidents avoided for the proposed remedial alter-
natives are 10 and 8, respectively, for the containment and treat-
ment option and the treatment option. The costs associated with
the implementation of the remedial technologies are represented
as a range (to reflect uncertainty) shown in Fig. 4. The cost per in-
cident avoided can be examined by constructing a line from the
number of incidents avoided which intersects with the range of
costs for the associated technology.
The range in costs per incident avoided ranges from approx-
imately SI.6 to $2.2 million for the containment and treatment
option which results in 10 avoided incidents. Alternatively, the
groundwater treatment option, which results in 8 avoided in-
cidents, has an anticipated range in costs from $0.9 to $1.1 mil-
lion. A comparison of these costs per incident avoided suggests
that the types of remedial action proposed for this hazardous
waste site are in the upper range of the costs per incident avoided
as displayed in Fig. 4.
It is also noteworthy to compare the incremental or margin^
cost associated with the per incident avoided costs when im-
plementing the more costly containment and treatment remedial
program. The two additional incidents avoided could have a cost
ranging from $2.5 to $6.5 million depending upon the exact cost
for each remedial alternative. These per incident costs far exceed
any of the per incident costs plotted on Fig. 4.
This raises the question of whether it is cost-effective to expend
the marginal costs of $2.5 to $6.5 million required to increase the
number of avoided incidents by two. It would be difficult to
justify this type of decision based solely upon consideration for
the cost of incident avoided. There may, however, be additional
factors which could support the decision to expend the additional
funds.
These factors relate to issues of implementability, performance,
reliability, environmental impact and safety. Each consideration
can impact upon selection of the remedial alternative. These
issues were not explicitly quantified in this analysis and will bead-
dressed to future work.
CONCLUSION
This analysis has demonstrated that it is possible to provide for
explicit considerations of quantitative risk assessments when
evaluating remedial action alternatives for implementation at
hazardous waste disposal sites. The comparison between remedial
options can be made on risk-based criteria with consideration of
the costs associated with incremental reduction in risk.
Assessments must be made of the costs associated with the
avoidance of a given incident. However, once a range of costs for
avoidance is established, it is possible to identify the most cost-
effective remedial alternative.
REFERENCES
I. Crump, K.S. and Howe. R.B., "The Multistage Model with a Time
Dependent Dose Pattern: Application to Carcinogenic Risk Assess-
ment," Risk Analysis. 4, 1984. 163-167.
2. Partridge, L.J., "The Application of Quantitative Risk Assessment
to Assist in Selecting Cost-Effective Remedial Alternatives," Proc.
National Conference on Management of Uncontrolled Hazardous
Waste Sites. Washington, DC, 1984, 290-299.
68 HEALTH ASSESSMENT
-------
Risk and Exposure Assessment of an
Abandoned Hazardous Waste Site
James D. Werner
ICF Technology Incorporated
Washington, D.C.
INTRODUCTION
Site Description
The Sylvester (aka "Gilson Road) site in Nashua, New Hamp-
shire (Fig. 1), was a former sand and gravel pit where hazardous
wastes were dumped openly and illegally along with solid wastes
from the late 1960s until November 1979. Solid waste, drums of
hazardous waste, bulk materials and liquids covered about 3 to 4
acres. Although various consultants who have worked on the site
used a figure of about 240,000 Ibs for the total weight of waste
deposited (based on 800,000 gal which was assumed to be over
96% water and exclusive of drummed surface waste), the total
could well be 30 times this figured7 Like many illegal sites,
however, the quantity can never be known with any precision or
confidence, because few records exist.
The Sylvester site is located outside the town of Nashua off
Route 111. Immediately adjacent to the site are two mobile home
communities and a small tributary (Lyle Reed Brook) to the
Nashua River. In the fall of 1982, a 6.2 acre cap and a slurry wall
were constructed. In 1984 the state began construction of a
groundwater recirculation and treatment system which began
operating in 1986 and is expected to achieve its goals in 2 years.
This analysis will consider the site conditions both before and
after these remedial activities.
Risk Assessment Overview and Context
As recently defined by the National Academy of Sciences,6 risk
assessment is:
". . .quantitative and qualitative evaluation of human
health risk from environmental exposures and includes
the uncertainties associated with model assumptions
used in inferring risk."
There is a wide variety of definitions of risk assessment including
the evaluation of physical hazards such as ionizing radiation and
floods. For the purpose of evaluating hazardous waste sites, risk
assessment has been defined by one expert5 as:
". . .the systematic scientific characterization of the
probabilities and types of adverse effects that may result
from chemical releases at the site."
Regardless of the definition, risk assessment methodology
generally includes the following four elements:
• Hazard Identification—Involves gathering and evaluating data
on the types of health injury or disease that may be produced
by a chemical and the conditions of exposure under which in-
jury or disease is produced.
• Exposure Evaluation—Involves describing the nature and size
of the population exposed to a substance and the magnitude
Figure 1
Sylvester Site — Nashua, New Hampshire
HEALTH ASSESSMENT 69
-------
and duration of the exposure. Exposure is used as an indicator
of dose.
• Dose-Response Evaluation (Toxicity Assessment)—Involves
describing the quantitative relationship between the amount of
exposure or intake (as an indicator of dose) to a substance and
the extent of toxic injury or disease.
• Risk Characterization—Involves the use of the data and analy-
sis from the first three components to determine the likelihood
that adverse health effects will occur in the exposed popula-
tion associated with that exposure. In cases where exposure
data are not available, hypothetical risk can be characterized
by use of hazard identification and dose-response evaluation
data alone.
The purpose of this paper is to apply this methodology to ex-
amine the effect of exposure assessment variables on the risk
characterization outcome. Uncertainty is perhaps the foremost
certainty in environmental risk analysis. Despite the uncertainties,
however, useful risk analyses can be developed by estimating
reasonable ranges of risk estimates and by using techniques such
as sensitivity analyses and worst case assessments. Both the basis
and the result of various exposure assessment variables will be ex-
plored. Because evaluation of all potential routes of exposure is
beyond the scope of this paper, only one surface water route and
one air route will be considered.
SOURCE CHARACTERIZATION
Waste Characterization
Although there are almost no records concerning the quantities
and types of wastes that were disposed, some insight on their
nature can be obtained from information documented during an
inspection of the drummed wastes and groundwater contamin-
ants. The majority of the liquid wastes were comprised of vola-
tile organic solvents including mixtures of aliphatic ketones and
esters, alcohols, substituted aromatics and volatile chlorinated
solvents. Many of the waste liquids were similar in appearance
and odor to various paint thinners, varnish, petroleum products
and paint products. Infrared spectrophotometer analyses in-
dicated the presence of alcohols, benzenes, toluenes and xylenes.
Toluene and xylene were the predominant chemical constituents.
For most of the waste solvents, the vapors were easily detectable.
Another group of wastes were chemically classified as organic still
bottoms, consisting of organic polymerized by-product residues
from polyurethane foam production. The contaminant most
often found in groundwater at the highest concentration is
tetrahydrofuran.
Tetrahydrofuran (THF) often is found as an artifact in
chemical analyses because of its use as a plasticizer. Because THF
may leach out of polyvinyl chloride (PVC) monitoring well tub-
ing, artifact THF usually is found at higher concentrations in new
wells than in old wells. Also, THF concentrations tend to decline
over time in a newly constructed well. Finally, if the artifact oc-
curs as a result of analytical apparatus (e.g., tubing) rather than
PVC monitoring wells, and, if analytical procedures are consis-
tent for all wells, then the THF concentrations are uniform across
wells in many locations. Because tetiahydrofuran was found in
high concentrations in the groundwater (3,000 mg/1) from wells
of a variety of ages but localized to certain locations, it is not
believed to be an artifact.
No pesticides or PCBs were encountered in the sampled drums.
This negative observation is important because these chemical
groups are more persistent and tend to bioaccumulate more than
most other substances found at hazardous waste sites, and be-
cause disposal costs for PCBs may be twice as much as standard
RCRA-hazardous waste.8
These analyses of drummed wastes are not necessarily indica-
tive of the wastes at the site. Wastes also were disposed in bulk on
the surface and through a makeshift pipe. These other methods
may have accounted for most of the waste disposed. The lack of
information on the nature and extent of the contaminant sources
is probably the most significant data gap in the risk assessment of
this site. The estimates of the wastes on-site will be discussed fur-
ther below.
Release Estimation
Contaminated groundwater from the site flows northwesterly
toward Lyle Reed Brook, which is about 680 ft from the site and
flows into the Nashua River. Groundwater, sampled at test wells
downgradient of the site and upgradient of Lyle Reed Brook
(e.g., HB-2), contained up to 123 mg/1 methylene chloride, 31
mg/1 chloroform, 330 mg/1 trichloroethylene, 1.7 mg/1 arsenic,
640 mg/1 iron and 115 mg/1 manganese. Although the concentra-
tions of these contaminants in surface waters were substantially
lower than those found in the groundwater, they were adequate to
eliminate all macrobiotic stream life and to cause a nuisance to
nearby trailer park residents from odorous air emissions.
Sometime before 1981, the top of this leachate plume seeped into
Lyle Reed Brook which, via the Nashua River, is a tributary of the
Merrimack River (Fig. 1) and provides drinking water to the
towns of Lowell, Lawrence and Methuen, Massachusetts.1 The
plume of contaminated groundwater at the Sylvester site wai
estimated in January 1982 to be roughly 30 acres in area, 1,500 ft
long and 100 ft deep. This is approximately five times the size of
the actual site area (6 acres) and almost ten times the size of the
original disposal area (3-4 acres). The nature and size of the plume
varied with the concentration and type of pollutants measured.
For volatile organics, a lobe of the plume extended con-
siderably beyond Lyle Reed Brook in January 1982 before the use
of the groundwater recirculation system. This lobe of the plume
was measured at 10 mg/1 of total volatile organics beyond Trout
Brook Road, at least 800 ft beyond the edge of the site. The
source of the plume of volatile organics was centered at the sub-
surface leaching trench leading from the rear of the C&S Disposal
Company Garage.
In late 1980 the "metals plume" (total summed metals at
greater than 1 mg/1) extended beyond Lyle Reed Brook. At the
same time, the volatile organics plume had not yet reached Lyfc
Reed Brook. This suggests that, because metals typically travel
slower than organics, they were in the ground longer than the
organics. In addition, because the metals plume source appeared
to be centered on the eastern edge of the site about 400 ft from the
infiltration drain leading from the garage, it may have emanated
from another source.
The leachate discharge from the site originally was estimated at
about 88,000 gal/day. Following construction of the slurry waU
and cap in fall 1982, this flow rate was reduced to 30,000 to
55,000 gal/day. Because the flow rate was expected to be reduced
to 6,000 gal/day, groundwater is believed to be flowing under the
slurry wall through fractures in the bedrock or through the slurry
wall due to corrosion.1'4 Of the groundwater flowing off-site,
about one-third was expected to breakout into Lyle Reed Brook,
while an additional one-third was predicted to flow into Trout
Brook.
Initially, the three primary potential public health threats caused
by the site were: (1) the contamination of the Merrimack River,
which is used as the drinking water source for the town of Lowell,
Massachusetts.The state predicted that at the Lowell town pump-
ing station the water quality criteria for arsenic (2.2 ng/1) would
be exceeded by a factor of 6.87; (2) the threatened contamination
of several private drinking water wells at houses along Route HI
by the plume of contaminated groundwater, which migrated at
70 HEALTH ASSESSMENT
-------
about 1.6 ft/day; and (3) an air pollution problem caused by
chloroform volatilization from Lyle Reed Brook into the nearby
trailer park at ambient levels exceeding chronic lifetime exposure
limits (MEGs). In addition to these public health threats, an odor
nuisance was created by volatilization of organics (primarily di-
ethylether and dimethyl sulfide) from Lyle Reed Brook.
The residents of Jensen's Trailer Park are not dependent upon
local groundwater resources for drinking water because they are
served by a municipal system. The residents along Route 111,
however, who are in the path of the contamination plume, use
private wells for their drinking water. Because these eventually
were expected to be contaminated, the houses were connected to
city water from a distant municipal well in 1981. Other nearby
private wells, such as the Pennichuck W.D. well, were not in use.
The expected arsenic contamination problem was discounted later
because naturally high arsenic concentration made this apparent
contribution insignificant.
In addition to determining the amount and routes of release,
the releases should be characterized chemically. Again, because
the source material is not precisely known, the groundwater will
be assumed to be the source. All groundwater monitoring analysis
results logs were entered onto an IBM "Lotus 1-2-3" spread
sheet, and means, median and maximum concentrations were de-
termined. To facilitate further data management, chemicals were
separated into three groups (A, B and C) according to their max-
imum concentration (see groups A and B listed in Table 1).
Table 1
Chemicals Found in Groundwater at Sylvester Site
Group A
(1,000 ^g/1)
Group B
(1 /ig/l to 1
30 bis-chloromethyl ether
16 bromodichloromethane
24 bromoform
15 carbon tetrachloride
21 2,1-dibromochloromethane
17 1,2-dichloropropane
18 trans-l,3-dichloropropylene
22 cis-l,3-dichloropropylene
25 hexachloroethane
4 vinyl chloride
35 acetone
20 benzene
28 chlorobenzene
5 chloroethane
12 chloroform
10 1,1-dichloroethane
13 1,2-dichloroethane
9 1,1-dichloroethylene
29 ethylbenzene
41 ethyl ether
36 isopropyl alcohol (IPA)
6 methylene chloride (MeCl)
37 methyl ethyl ketone (MEK)
39 methyl isobutyl ketone
26 perchloroethylene
33 tetrahydrofuran
27 toluene
14 1,1,1-trichloroethane
19 trichloroethylene (TCE)
34 xylene
EXPOSURE ANALYSIS
Exposure analysis is perhaps the most important step in ex-
posure assessment—partly because it is the least understood—but
also because it can dramatically affect the final risk characteriza-
tion through relatively small changes in assumptions. The two
basic steps: (1) identify exposure pathways and (2) estimate ex-
posure point concentrations, provide a systematic method for
evaluating exposure. Although this method does not eliminate
uncertainty, it does assist in organizing and analyzing existing
data, elucidating specific data weaknesses and providing the data
necessary to evaluate the exposures in the next steps of the risk
assessments.
On the basis of the exposure analysis, it is possible to evaluate
the primary sources of uncertainty regarding estimates of exposure
concentrations. A general paucity of data plagued many estimates.
But, specific sources of uncertainty include the following:
• Source characterization (nature and amount)
• Discharge rate from source
• Attenuation of contaminants (volatilization, hydrolysis, etc.)
• Receptor location and intake
The nature and extent of the source and discharge from the site
are described briefly above in the site description. The lack of
data regarding contaminants and site conditions prevented a more
precise treatment of contaminant attenuation. Finally, receptor
location and intake quality are probably the greatest areas of un-
certainty—e.g., will the site be used following cleanup?
Potential exposures to volatile organic chemicals may occur
from the air, groundwater and surface water. The highest poten-
tial exposure concentrations from the site probably would be
from ingestion of contaminated groundwater. Actual intake
quantity should be insignificant in the near term because ground-
water use is unlikely. Groundwater on the site likely will not be
used for several decades because the state owns the site and will
control access and use. Beyond a few decades, however, these in-
stitutional barriers may prove ineffective, while the site may re-
main highly contaminated. The risk analysis framework is useful
for identifying, quantifying and evaluating all potential exposure
pathways, however unlikely, in the near term.
Identify Exposure Pathways
Table 2 shows the possible human exposure points. Although
certain points are very unlikely sources of exposure (e.g., on-site
wells), they are included here for completeness and to
demonstrate a point about receptor uncertainty.
Estimate Exposure Point Concentrations
Estimating exposure point concentrations is the most complex
part of the exposure assessment for two reasons. First, the estima-
tion typically involves mathematical modelling of pollutant
transport and fate, which often requires extensive data collection
efforts. Second, estimating exposure involves manipulation of a
massive amount of data. To simplify this paper, only two ex-
posure points—Nashua River contaminant concentrations and
ambient air above Lyle Reed Brook—were considered. Worst
case data and situations will be used, but the results should be
placed in perspective with the necessary qualifications.
Nashua River at Trout Brook
The predicted concentration of Group A contaminants in the
Nashua River where Trout Brook enters are presented in Table 3.
These estimates are based on a dilution factor from Trout Brook
(d = 111) and appropriate half-life values. This d-value from
Trout Brook is used instead of the minimum cumulative dilution
factor (using the highest breakout rate) from the breakout zone at
Lyle Reed Brook (12,866) for simplicity. By using the Trout
Brook contaminant concentrations, the previously calculated ef-
fects of volatilization (from the Lyle Reed Brook breakout zone)
and other attenuation effects (using the half-life values)
automatically are considered. One-third of the contaminated
groundwater flowing off-site was estimated to be breaking out into
Lyle Reed Brook.
The dilution factor is determined by dividing the average flow
rate of the Nashua River by the discharge rate from Trout Brook.
The flow rate (597 ft3/sec) of the Nashua River used was a mean
of 5 years of records (1975-1980) from the U.S. Geological
Survey. For calculating the attenuation of the contaminants using
the half-life value, a distance of 1,400 ft and a flow velocity of
53.4 ft/min (76,896 ft/day) or 0.02 days travel time between Lyle
HEALTH ASSESSMENT 71
-------
Reed Brook junction with Trout Brook, or Nashua River were
used. For predicting contaminant concentration at the specific
locations (Nashua River at Trout Brook), instantaneous and com-
plete homogeneous mixing was assumed.
Table 2
Possible Human Exposure Points
CkUtlnf off-tit* w*ll
•lent ftouu lit
Downgrtdltni
Table 3
Dilution Concentration In Nashua River
at Trout Brook for Group A Chemicals
10 1,1,
1) l.t-
ff l.l-O
99 •tftaM
».1|T
3 8
•
in
n
ITO
MO
H.tOi
1.U1
i.ooe
in
11.900
•H
It
T*
M
U
II
10
ft
tl
M
11
01
I?
-------
or surface water concentrations that were higher than observed
during the actual air sampling period.
FINAL STEPS
The final steps of a risk assessment—intake estimation and risk
characterization—are beyond the scope of this paper except to
describe in general terms. Intake is used as a surrogate for actual
toxicological dose because of the complexities of calculating
dosages. For estimating drinking water intake, standard assump-
tions (a 72 kg adult drinking 2 1 of water daily) are used to deter-
mine the dose (mg/kg) from water concentration (mg/1). Similar-
ly, a dose is estimated for children (10 kg) and adults (70 kg)
breathing about 5 and 20 mVday, respectively.
Risk characterization is at least as complex as exposure assess-
ment. A "potency factor" for each chemical and route of ex-
posure (oral ingestion, inhalation and dermal contact) can be used
to determine a cancer risk probability associated with observed or
predicted levels of exposure. The U.S. EPA's Carcinogen Assess-
ment Group has derived several potency factors which are listed
in the U.S. EPA's draft Public Health Assessment Manual for
Superfund.
Shortcomings include: (1) the limited number of chemicals for
which potency factors have been estimated; (2) the limited out-
comes for which estimates are performed (e.g., cancer); and (3)
well-documented uncertainties regarding extrapolations from
animal data.'
CONCLUSIONS
The results of this type of analysis may be used to make multi-
million dollar decisions affecting thousands of people for several
generations. Because the results of each step feed into the next
step, it is important that any assumptions used are reasonable. In
the case of this exposure assessment there were two major uncer-
tainties. First, there were data gaps such as source characteriza-
tion and exposure concentrations. Second, the future receptor
locations (on-site, downstream, down wind) were uncertain.
Resolution of these problems will require that the health assess-
ment professionals work closely in design and execution of the
data collection efforts during the remedial investigation.
ACKNOWLEDGMENT
The author gratefully acknowledges the generous assistance of
NH WSPCC officials who provided raw data for this analysis, as
well as the NIOSH Educational Resource Center funding which
made it possible.
REFERENCES
1. Anderson, D.C. et al. "Organic Leachate Effects on the Permeability
of Clay Liners." Proc. of the Second National Conference on the
Management of Uncontrolled Hazardous Waste Sites, Washington,
DC, Oct. 1981, 223-229.
2. Anderson, E., "Qualitative Approaches in use to Assess Cancer
Risk," Risk Analysis, 3, 1984, 277-295.
3. GHA. "Hazardous Waste Site Investigation Sylvester Site, Gilson
Road, Nashua, New Hampshire," Vols. I, II, III, GHR Engineering
Corp., New Bedford, MA, July 1981.
4. Green, W.J., Lee, G.F. and Jones, R.A., "Clay-soils Permeability
and Hazardous Waste Storage," JWPCF, 53, 1981, 1347-1354.
5. Jones, B. and Kolsky, K., "Approaches to Computer Risk Analysis
at Uncontrolled Hazardous Waste Sites." Proc. of the Fifth National
Conference on the Management of Uncontrolled Hazardous Waste
Sites, Washington, DC, 1984, 300-305.
6. National Research Council, National Academy of Sciences. Risk As-
sessment in the Federal Government: Managing the Process, National
Academy Press, Washington, DC, 1983.
7. Weston, R.F., "Final Sylvester Hazardous Waste Dump Site Con-
tainment and Cleanup Assessment" (Dated Jan. 1982. Revised May
1982) by Roy F. Weston, Inc., with Environmental Engineering Con-
sultants, p. 21.
8. Werner, J.D., Yang, E.J. and Nagle, E., "Remedial Action Man-
agement and Cost Analysis," Proc. of the Fourth National Confer-
ence on the Management of Uncontrolled Hazardous Waste Sites,
Washington, DC, Nov. 1983, 370-375.
HEALTH ASSESSMENT 73
-------
Death or Cancer—Is There Anything Else?
B. Kim Mortensen, Ph.D.
Agency for Toxic Substances and Disease Registry
Atlanta, Georgia
INTRODUCTION
Americans seem to have a mental fixation on cancer and death.
As a result, many emergency response actions focus on death and
cancer to the exclusion of other public health concerns. The news
media, using information provided by members of the emergency
response group, can create public reactions to toxic releases that
are out of proportion to the actual health threat. Environmental
and health professionals must respond to the public's concern,
but are we guarding the front door of the chicken coop while the
fox is slipping in the back door?
I believe that, as professionals involved in environmental and
health activities, we are not fully protecting public health and
preventing human suffering if the primary health concerns during
a release of hazardous substances are death and the risk of can-
cer. This paper first discusses why some believe these two out-
comes are often the primary health concerns, and then reviews
what health effects may be ignored or at least accorded lower
priority.
PUBLIC PERCEPTION
One of the main objectives of the news media is to inform the
public; but another objective is to assure the continuation and,
hopefully, the growth of some form of rating of their popularity.
These two objectives are interrelated. For example, if a television
news program does not report a hazardous substance release and
do it in an interesting way, viewers may turn to another station.
The result of this is that news must be presented in a way that
catches the public's attention. Career advancement and income of
reporters, photographers and cameramen in news departments
depend in part on how much of their material is used and whether
it is "above or below the fold." Who wants to read that nothing
frightening, dangerous or exciting happened today? If there is a
possibility that the release of a hazardous material threatens peo-
ple or property and some aspect of the release might be frighten-
ing to the public, that aspect of the information will be (and
should be) reported.
There are strong institutional forces seeking to discover or
create controversy and public interest. Environmental and public
health professionals have very different agendas from news pro-
fessionals. This statement is not made to condemn news media,
it is simply stated to show how they work and the limits placed on
their reporting.
Information and education are two different concepts. The
methods used to inform and educate are different, and so are the
results. The public must be both informed about emergency re-
sponse needs and educated about emergency preparedness and
contingency planning. They must know if they need to respond to
a hazardous substance release, what level of response is appro-
priate to the situation and how to react.
People's perceptions of risk often are inaccurate and these per-
ceptions are influenced by factors such as the memory of past
events and imagination of future events. Studies by Lichten-
stein, Slovic and FischhofP and others have shown that dramatic
and sensational causes of death, accidents and cancer tend to be
overestimated. Risks from undramatic health problems like em-
physema, skin irritation or infected cuts tend to be underesti-
mated, even if they cause greater suffering and loss of workdays.
News coverage often reflects this tendency and may contribute
to the public's perceptions of what are the greatest risks. Table 1
shows how the biases in news coverage in two different news-
papers parallel biases in perceptions. Fig. 1 graphically illus-
trates this hypothesized relationship.
The public's perception of risk is likely to strongly affect their
reaction to news of a toxic release and what they might demand
Table l
Statistical Frequency and Newspaper Coverage
In Two Newspapers for 41 Causes of Death
Rat* par
105 Million Subjacti'
Cauia of D*atn U.S
1.
1.
3.
10.
11.
11.
11.
14.
19.
K.
17.
u.
1*.
JO.
11.
11.
13.
X.
15.
36.
27.
at.
19.
10.
11.
32.
33.
34.
35.
)«.
J7.
11.
19.
40.
41.
Stallpox
Poiaonino by vitaaina
ftotul ia«
Maaalaa
riraworfca
Saallpox vaccination
whooping cough
Polio
Vanoaoua bit* or Btlng
Tornado
Li9htnlng
Hon-vano«oue anlaal
Flood
Cxcaat cold
syphiua
Pragnancy, birth, abor.
Infactioua hapatitla
Appandicltia
Clactrocution
MV/train colllaion
Aathaa
Firaara accldant
Polaon by aol id/liquid
Tubarculoaia
rlra and flaua
Drowning
Laukaala
Accidental (all*
Hoaicida
Caphyaaaa
Sulclda
Braaat cancar
Dlabataa
Motor vahicla accldant
Lung cane r
Sto»ach c near
All accltf nt«
Strokt
All cane*
Haart dia •••
All dlaaa a i.
Ra*idant» Catiaataa
0 57
1 101
> !•}
5 161
a 1(0
( 1}
15 93
17 97
4« 150
90 5(4
107 91
119 174
305 736
1)4 314
• 10 491
451 1,144
677 545
901 605
,015 7(a
,517 6(9
.•ft 50«
,155
.541
,690
7,310
7,}>0 •
14,555
17,415
ll,«60
11,710
14.600
31,1(0
11,950
55.J50 4
75,150
95,110
111,750 1
109,100
111,000 4
7)1,000 1
740,450 »
.345
,011
(51
,))<
,000
,49(
,(75
.512
,I4>
.(79
.'64
.476
, 161
,764
,383
.•79
,109
.609
.599
,»l
Raportad
Daatha
A
0
0
0
0
0
0
0
0
0
)(
1
4
4
0
0
0
0
0
5
9
4
IS
171
1
19
0
0
299
3
0
715
11
15
49
111
B
0
1
1
4
6
2»
1
1
59
1
)
I
Tot«l number of reports (causes 29, Ji, 37, 41)
Source: Combi, B. and Slovic, P.. Journalism Quart , 56. 1979, 837.
1113 910
74 HEALTH ASSESSMENT
-------
FACTOR Z
UNKNOWN RISK
Figure 1
Hypothesized relationship between media coverage (size of dot) and
nature of the hazard. Hazards perceived as unknown and dread would
receive greater coverage than other hazards. (Adapted from Slovic, P.,
"Informing and Educating the Public about Risk." In press.)
of their public health officials. A mathematical technique called
factor analysis arrays characteristics the public uses to describe
hazards (Fig. 2). It is clear that chemicals in general, and spe-
cific hazardous materials in particular, all are viewed similarly.
Hazards at the top were described as not observable, unknown to
those exposed, effect delayed, new risk and risks unknown to
science. Likewise, those along the right side were considered un-
controllable, dreaded, catastrophic, fatal, not equitable, and so
forth, as shown for Factor 1.
UNCERTAINTY IN ENVIRONMENTAL
HEALTH SCIENCE
One of the greatest difficulties in tieing actions to concerns
about cancer is that if an exposure were to cause cancer, the
disease probably would not appear clinically for years or even
decades. To overcome this time delay of cause/effect relation-
ships, we have come to rely, in part, on statistical models derived
from high-dose experiments with animals. When the weight of
evidence is considered, the U.S. EPA Cancer Assessment Group,
the International Agency for Research on Cancer or another
agency assigns a level of risk to a chemical. For example, a chem-
ical may be designated a possible human carcinogen, a probable
human carcinogen or a human carcinogen.
The modeling process introduces many uncertainties and pol-
icy choices that may be hidden in the technical intricacies of the
mathematics of modeling. A recent article reported that bioassay
data were fit to four analytical models used to estimate cancer
risk: logit, multistage, probit and Weibull. These four models are
representative of models currently in use. There are no biological-
ly based criteria for choosing one model over another and no
assurance that the predicted risk lies in the range predicted by the
model.
All models used the same base: 50 )ig/l trichloroethylene in
drinking water. For one model the risk estimate is about 10~2,
whereas with another the estimate is 10-10. This means that the
estimated risk of excess cancer in a population exposed to this
level of TCE for 70 years (assuming ingestion of 2 1 of water per
day) would range from one per hundred persons exposed to one
per ten billion persons exposed. These estimates provide a range
of uncertainty equivalent to not knowing whether one has enough
money to buy a cup of coffee or pay off the national debt.
The rationale for using the most widely used model is that it is
unlikely that its risk number underestimates the true risk. Results
usually are given only as an upper bound estimate of risk (95%
upper confidence limit on the probability of a response). There
are several difficulties in relying solely on the 95% upper confi-
dence limit on risk:
• The upper confidence limit on risk may be very much larger
than the estimate of risk
• The lower bound estimate of risk from the model may be zero,
that is, there is no excess risk
• These models produce the least accuracy and precision at the
low dose levels extrapolated from animal data; these are the
levels of environmental exposures.
• With this model, the upper bound on the risk can be small when
the estimate of risk is small or when it is not small. Thus one
cannot tell if the bounds are extremely conservative of defined
health effects or if they are only slightly conservative.
The sole reliance on this numerical estimate of risk may lead to
large expenditures of effort and money without any assurance
that this protects public health any better than a lesser effort.
The credibility of scientists may be challenged when the public
hears or sees that the experts appear to disagree strongly about
the risk from a chemical release. One problem is the difference
between the process of science in reaching consensus about a
question and the process of law which sets two opposing views of
expert witnesses at the opposite extremes.
The legal need for relative certainty and probable cause drives
expert opinion to opposite extremes of a question, whereas the
scientific process leads to general agreement and consensus.
Another source of uncertainty at a hazardous substance spill
site is the estimate of human dose. Many assumptions are made
for inhalation, skin absorption, ingestion and absorption in
modeling total body uptake. These assumptions often rely on
average values which may not represent the situation at hand. For
long-term exposures, one has the luxury of time to measure the
critical parameters, but at a spill site (for example at a truck or
train derailment), speed in response is often critical. I believe that
one source of uncertainty can be reduced greatly by testing en-
vironmental levels of the chemicals where the population at risk
is located, as well as at the site.
Input from a health scientist can determine the specific needs
on a case by case basis. Without the kind information that a
health scientist knows how to gather best (i.e., human exposure
data and symptoms to look for), the health outcomes reported at
these sites will continue to be, "no one died, so we must have
done the right thing." It is difficult to find an unexciting effect if
no one looks for it.
DIFFERENCES IN RISK PERCEPTION
The scientific community which responds to releases of haz-
ardous materials must understand better their own as well as the
public's perceptions of what constitutes a certain level of risk. We
can be reasonably sure that all communities will not be alike in
this, but how greatly they differ can be discovered only through
more field research. Once we have a deeper knowledge of various
HEALTH ASSESSMENT 75
-------
perceptions of risk, we must improve communication of those
perceptions among the involved groups. Greater and earlier pub-
lic involvement in the process of risk evaluation may help.
Federal and many state agencies mandate or suggest that the
public be a part of the planning or assessment phases of emer-
gency and remedial response. Emphasis should be placed on see-
ing that the public truly has a chance for meaningful involve-
ment. A number of states and federal agencies are channeling re-
sources to the local level for research and training in risk com-
munication.
REDUCING UNCERTAINTY IN RISK ASSESSMENT
We can improve the risk assessment process to make it more
realistic in emergency response actions by:
• Developing and using physiologically based animal exposure
models to derive dose response relationships; pharmacokinetic
models currently under development try to account for re-
sponse at the level of the target cells.
• Collecting better data on human exposure by improving and
calibrating dispersion models; developing methods for more
rapid collection and analysis of biological samples; improving
and expanding data bases on background levels of chemicals
in humans; and continuing to search for new methods to de-
tect exposure, such as DNA adducts, subclinical physiological
response and nerve conduction tests.
• Expanding our knowledge about dose/exposure responses in
animal exposure tests to improve the validity and accuracy of
interspecies comparisons.
tl.clf.e «lr 1 >.,! (Uwcll*
MC10K I
• It.i
hl*r*«t*rti*« • I.<.l-»
I PllttfU*! •
• "••"•» , MI
• 'Vlllt f««ll
• 4«ie CiMxit ICO)
• 0-COI
FACTOR 1
~-^-|-
• CMl M1«l*f lOtlfltfll
• Ultrvitf folllilwn
' >**!• Accl««*U
Controllable
Nol Dread
Nol Global Catastrophic
Coiuequencci Nol Fatal
Equitable
Individual
Low Riik to Future
Generation!
Easily Reduced
Riik Decreailni
Voluntary
Doetn't Affect Me
Factor 2
Not Dewrvable
Unknown 10 Those
Ei posed
Mf«i Delayed
Nc» Riik
Risks Unknown lo
Science
Doervable
Known lo Thote Elpowd
Effect Immediate
Old Riik
Rliki Known lo Science
Uncontrollable
' Dread
Global Caiaitropic
Consequences Fatal
Not Equitable
Calaiirophic Factor I
Hi«h Riik to Future
Generations
Nol Easily Reduced
Riik Incraulni
Involuntary
AftectiMe
Figure 2
Factor analysis of risk relationship among hazards. (Adapted from Slovic, P., "Informing and Educating the Public about Risk." In press.)
76 HEALTH ASSESSMENT
-------
IMPROVING THE SITUATION
There must be more public education about the true risks from
releases. Knowledge of the process and of how risk estimates are
made will encourage appropriate risk reduction behavior and an
accurate understanding and healthy amount of concern by the
public about the potential danger of chemical release. The public
should be neither apathetic nor panicked.
What then are some other issues that should be addressed? The
public is not the only group whose health should be considered.
Are the workers at the scene fully informed about the kind of
risks that exist at the site? Should they be protected from skin irri-
tation with proper protective suit? Is there a risk from lung and
eye irritation that might result in eye damage, blindness or res-
piratory collapse? Is physical protection needed from falling and
exploding objects? Is everyone wearing hard hats and protective
goggles if needed? If a worker or victim is contaminated with a
toxic chemical, do the ambulance crew and emergency room staff
have proper personal protection equipment to treat the victim?
Will the victim contaminate the ambulance and emergency room?
If we are going to try to change an individual's perception of
threat and understanding of risk, it must be done before the prob-
lem occurs. This process must involve active planning for a haz-
ardous materials release by all individuals who may be involved.
Only then will they be prepared when a release occurs.
There are several key points in this idea. First, there must be
"active planning." Preparation for a release is not something that
can be done for someone, and it is not an activity that can be done
in a vacuum. The city planning agency cannot guess how the
health department will respond to a hazardous materials release,
so both agencies must work together to prepare for the time when
a release occurs. Almost everyone in the community should be a
part of the planning team, and, just as in a sport, the team must
practice to assure that each member knows his role and the re-
sponsibilities of the other players.
In preparing to respond to a release of hazardous materials,
the response team must also develop an active cooperative rela-
tionship with the industrial community. Manufacturers, formu-
lators and commercial users of chemicals in the area can provide
expertise and information on their products. These companies
also can supply emergency response equipment and trained per-
sonnel. Throughout the country, this type of cooperative relation-
ship is helping to prepare for accidental chemical releases. This is
particularly evident in the Community Awareness and Emergency
Response (CAER) program of the Chemical Manufacturers'
Association.
Another important partner on this team is the media. A part-
nership should be established with them, also. Biologists would
classify this relationship as symbiotic; for each group, media and
responders, needs the other and each will profit from the relation-
ship. The media must inform the public of potential events, place
the situation in proper perspective and advise the community of
the actions to take when an event occurs. The response communi-
ty must develop a trusting relationship with the media before the
event.
The community also must become involved in the planning pro-
cess. They must be aware of the risks from a chemical release and
the plans for action that might be required. If they are to act ap-
propriately, the community, the government, the media and the
corporate groups must trust each other.
CONCLUSION
In a recent release, a large evacuation was ordered. However,
based upon the perception of the problem by the community and
their belief that the city was overreacting, many individuals did
not relocate or they left the area and returned to their homes prior
In a Scientific Setting
In a Court of Law
Figure 3
Institutional Forces on Scientific Views in a Scientific Setting
and a Legal Setting
to an "all clear" message. This early return to the danger area
resulted in many residents placing themselves at increased risk.
We use the phrase "when an event occurs." It is not a question
of whether an event will occur; a hazardous material incident will
occur. The only factor is when. Contingency planning must be in-
itiated and must extend beyond the scope of fire trucks, protective
clothing and tank patches. It must extend to the community to in-
crease the understanding of risk—total risk in its broadest sense.
Preparation would include representatives from major groups
and institutions to assure that response issues are addressed.
REFERENCES
1. Slovic, P., "Informing and Educating the Public About Risk." In
press.
2. Slovic, P., Lichtenstein, S. and Fischoff, B., "Modeling the societal
impact of fatal accidents," Management Sci. 30, 1984, 464.
3. Sielken, R.L., "Individualized response model for quantitative can-
cer risk assessment." Paper presented at Joint Meeting of The Risk
Assessment Subcommittee of The American Industrial Health Coun-
cil. The Health and Safety Committee of the Chemical Manufac-
turers Association. Washington, DC, 1986.
4. Andersen, M.E., Clewell, H.J. Ill, Oargas, M.L., et al., "Physio-
logically-based pharmacokinetics and the risk assessment process for
methylene chloride," Toxicol. Appl. Pharmacol. In press.
5. Cothern, C.R., Coniglio, W.A. and Marcus, W.L., "Estimating
risk to human health; TCE in water," Environ. Sci. Techno! 20
1986, 2. ' '
HEALTH ASSESSMENT 77
-------
Missouri Dioxin Studies:
Some Thoughts on Their Implications
John S. Andrews, Jr., M.D.
Paul A. Stehr-Green, Dr. P.H.
Richard E. Hoffman, M.D.
Larry L. Needham, Ph.D.
Donald G. Patterson, Jr., Ph.D.
Centers for Disease Control
Center for Environmental Health
Atlanta, Georgia
John R. Bagby, Jr., Ph.D.
Daryl W. Roberts
Missouri Department of Health
Jefferson City, Missouri
Karen B. Webb, M.D.
R. Gregory Evans, Ph.D.
St. Louis University School of Medicine
St. Louis, Missouri
ABSTRACT
In 1971, 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD)-con-
taining sludge wastes were mixed with oils and sprayed for dust
control on various residential, recreational and commercial areas
in Missouri. By February 1986, 40 sites in Missouri had been con-
firmed as having at least 1 ppb of 2, 3, 7, 8-tctrachlorodibenzo-p-
dioxin (TCDD) in soil related to disposal of waste from a hexa-
chlorophene production facility in Verona, Missouri. In order to
investigate these TCDD contaminations, several studies have been
undertaken.
Results of a pilot epidemiologic study recommended that addi-
tional studies looking at possible urinary tract, liver, neurological
and immune system effects should be carried out. Results from
a larger study of persons with exposure to TCDD in a residential
setting reported in April 1986 showed that persons exposed to
TCDD: (1) did not have any statistically significant increased
prevalence of clinical illness diagnosed by a physician, (2) had
no significant pattern of differences on medical history, physical
examination, serum and urinary chemistry studies or neurologic
tests, (3) showed some differences in liver function test results
which may serve as a biological marker of exposure or as a sign
of subclinical effects and (4) had an increased prevalence of
anergy (11.8% vs 1.1%) and relative anergy (35.3% vs 11.8%)
on immune testing compared with persons who were not known
to have been exposed to TCDD. Repeat immunologic studies
of persons with anergy and relative anergy are in progress.
Studies of adipose tissue from persons exposed to TCDD in
occupational, recreational and residential settings also are in
progress. Follow-up studies on the persons with adipose TCDD
are underway. These findings suggest that additional studies are
needed in order to develop a more complete understanding of the
risks and appropriate public health interventions in situations of
community exposure to environmental dioxins.
INTRODUCTION
Historical Perspective
In 1971 approximately 29 kg of 2, 3, 7, 8-tetrachlorodibenzo-
p-dioxin (TCDD)-contaminated sludge wastes, which originated
as a by-product of hexachlorophene production in a southwest
Missouri plant, were mixed with waste oils and sprayed for dust
control throughout the state. Almost 250 residential, work and
recreational areas (including several horse arenas) were thought to
be contaminated, including the town of Times Beach. To date,
approximately 40 sites have been confirmed as having at least
1 ppb of TCDD in soil. At first, levels as high as 35,000 ppb were
measured in soil at one of these sites; at the time of these initial
studies, isolated levels over 2,000 ppb existed in some contam-
inated areas, but most detectable levels in soil samples ranged
from several hundred ppb down to less than 1 ppb.
About one-third of the confirmed sites were contaminated with
peak levels in excess of 100 ppb; one-half of these were in resi-
dential areas. These sites varied widely in their potential for lead-
ing to human exposure' due to the lack of uniformity in geog-
raphy, topography, geology and characteristic land use. This vari-
ation has presented difficulties in the public health decision-mak-
ing process. Sites at which the levels of contamination were high
and which are in areas of frequent and regular access constitute
the greatest public health risk; however, at other sites, dioxin con-
tamination was in clearly circumscribed areas at subsurface
depths exceeding 15 ft, under paved areas, or in areas with lim-
ited land use. All of these considerations were taken into account
in assessing the risk of exposure for an estimated 5,000 individ-
uals from these contaminated areas during the period from 1971-
1983.
The earlier phases of this investigation focused on several sites
in eastern Missouri, but subsequent activities include all contam-
inated sites. The Division for Environmental Hazards and Health
Effects and the Division of Environmental Health Laboratory
Sciences in the Center for Environmental Health of the Centers
for Disease Control (CDC) had worked previously with the Mis-
souri Department of Health (MDH) in 1971 (the time the initial
contaminations occurred) after receiving a report of an exposed
child who presented with hemorrhagic cystitis;1 in 1974, this work
culminated in the laboratory identification of TCDD in the waste
oil. With further discoveries of widespread contaminations in
78 HEALTH ASSESSMENT
-------
mid-1982, MDH and CDC reinitiated public health activities on
the basis of new information and additional environmental data.
PUBLIC HEALTH ACTIVITIES
The case of dioxin illustrates many of the difficulties encoun-
tered in assessing health risks following long-term, low-dose ex-
posure to environmental chemical contaminations.2 At the time
of our initial investigations, there was no widely available method
for directly measuring dioxin levels in human tissue. The lack of
any direct measure of body burden or exposure substantially
hindered attempts to assess the degree of exposure to and con-
comitant health risk posed by environmental dioxins. In addi-
tion, data on human health effects were limited, thereby necessi-
tating reliance on animal experimental studies and/or cases of ac-
cidental acute intoxication in humans. Thus, risk assessment
methods were used to estimate risks to potentially exposed human
populations to serve as a basis for risk management decisions.3
In doing the exposure assessment calculations for contam-
inated residential areas in Missouri, we used an iterative simula-
tion model to estimate a 70-yr lifetime dose to an exposed person.
Extrapolating doses from chronic feeding studies in rats corres-
ponding to known levels of risk and using cancer as the disease
endpoint of concern, we concluded that residential soil TCDD
levels of ^ 1 ppb pose a level of concern for delayed health risks
in residential areas. Assuming that an entire area is contaminated
at 1 ppb, we estimated the excess lifetime cancer risk to an ex-
posed individual ranges from greater than 1/100,000 to less than
1/100,000,000. This risk estimate would amount to a 0.000023
absolute increase (equivalent to a 0.01% relative increase) over
one's "normal" 25-30% lifetime probability of developing can-
cer in the United States (RR = 25.0023/25 = 1,0001).
Thus, MDH and CDC issues advisories which stated that con-
tinued, long-term exposure to persons living in specified residen-
tial areas with 1 ppb or more TCDD contamination in the soil
posed an unacceptable health risk. The U.S. EPA then used these
advisories as the basis for risk management decisions.
In addition to ongoing review and assessment of U.S. EPA
environmental sampling data, MDH and CDC initiated four dis-
tinct public health actions in January 1983:
• Providing health education for both and medical and public
health community and the general public about current under-
standings of the health effects of dioxin exposures. A sum-
mary of the medical/epidemiological literature was prepared
and sent to physicians in eastern Missouri. On Jan. 18, 1983,
experts from government, academic institutions and industry
were brought together to give a seminar for the local medical
community. Individual consultations and toll-free hotlines
were established to answer questions from and concerns of
the general public.
• Providing a dermatologic screening clinic to the general public.
This clinic was intended to screen for cases of chloracne as an
indication of possible dioxin exposure. In February 1983, on
consecutive weekends, all residents of eastern Missouri who
had reason to suspect that they had been exposed and who had
current skin problems were invited to be seen at these screen-
ing clinics.
• Creating and maintaining a central listing of potentially ex-
posed individuals. This listing has enabled public health agen-
cies to keep in touch with and locate potentially exposed in-
dividuals for educational purposes or possible epidemiologic
and/or clinical follow-up. Specifically, if a reliable screening
method for TCDD in serum should become available, we will
be better able to assess exposure status and concomitant health
risks. Baseline and identifying information were collected in
the form of a Health Effects Survey Questionnaire designed to
elicit information on possible routes of exposure, life-style
habits, residential and occupational histories and medical his-
tory. It was also intended to serve as a screening tool for iden-
tifying a "highest risk" cohort on whom intensive medical
evaluations were focused and in compiling a community-based
data set from which epidemiologic inferences might be drawn.
• Designing and implementing a pilot medical study of a "high-
est risk" cohort. This research was conceived as a pilot study
of a group of persons presumed to be at highest risk of ex-
posure to environmental TCDD. It was intended to provide
preliminary information on possible health effects from these
exposures to enable investigators to develop more refined and
specific epidemiologic protocols to be used in further investi-
gations.
PILOT EPIDEMIOLOGIC STUDY
In this pilot study," we assessed potential health effects related
to dioxin exposures by three means. First, as previously men-
tioned, we developed a Health Effects Survey questionnaire to
elicit information on each person's exposure risk, medical history
and potentially confounding influences. We sought data for in-
dividuals believed to be at risk of exposure because they lived
near, worked at or frequently participated in activities near a con-
taminated site.
Second, we sponsored the dermatology screening clinic men-
tioned above.
Third, we reviewed approximately 800 completed question-
naires and selected 122 persons for inclusion in a pilot medical
study. We selected a high-risk group which comprised 82 in-
dividuals who reported living or working in TCDD-contaminated
areas or participating more than once per week, on the average, in
activities that involved close contact with the soil (such as garden-
ing, field/court sports, horseback riding or playing in soil) in con-
taminated areas with TCDD levels of between 20 and 100 ppb for
at least 2 years or levels greater than 100 ppb for at least 6 months.
We also selected a low-risk comparison group of 40 persons who
reportedly had had no access to, or regular high-soil-contact ac-
tivities in any known contaminated areas. Of the 122 persons
selected for study, 104 agreed to participate (68 at high risk and 36
at low risk of exposure).
In addition to being compared according to their responses on
the Health Effects Survey Questionnaire, these 104 persons were
assessed under a clinical protocol that included physical, neuro-
logic, dermatologic, hematologic, immunologic and liver function
testing.
The high-risk and low-risk groups were comparable in terms of
age, race, sex, education of head of household and interview
respondent distributions. The two groups did not differ signifi-
cantly in reporting other potential sources of exposure or the use
of prescription medicines. The only significant difference in life-
style habits was that the high-risk group reported exercising more
regularly (p CO.Ol).
We found no differences or consistent trends regarding the
prevalence of generalized disorders as reported in the question-
naires, the results of the general physical examinations or the
routine hematology tests (except for a higher mean platelet count
and a nonsignificant trend of diminished peripheral pulses in the
high-risk group).
No consistent overall trends or statistically significant in-
dividual diagnostic differences were detected for reproductive
health outcomes from the questionnaire material. No birth
defects were reported among children born to women in the high-
risk group after the time at which exposures could have occurred.
In the dermatologic screening, no cases of chloracne were seen
HEALTH ASSESSMENT 79
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in the 140 persons examined from the general community or in the
104 persons in the study groups. In addition, the study population
demonstrated no significant differences in all other der-
matological findings by either medical history or physical exam-
ination.
Results of the neurological examinations showed no significant
differences or patterns between the two groups from the self-
reported neurological conditions or from the neurological ex-
aminations, although a non-statistically significant diminution of
vibratory sensation at 256 Hz was noted in the high-risk group.
As reported in the medical histories, there were no differences
in prevalence of immune disorders. On physical examination, the
only significant difference was a suggestion of a greater
prevalence of palpable nodes in the low-risk group. Laboratory
analyses showed no statistically significant differences between
the two groups, although there was a trend of diminished
response to the antigenic skin tests and a greater prevalence of ab-
normalities in comparisons of parameters from T cell subset
assays in the high-risk group.1
In regard to the hepatic system, no trends or significant specific
problems were reported in the medical histories. On physical ex-
amination, there was a greater prevalence of hepatomegaly in the
high-risk group, but this finding also was not statistically signifi-
cant. There were no statistically significant differences between
the two groups on tests of hepatic function except for elevated
mean urinary heptacarboxylporphyrin in the low-risk group.
However, the two groups showed no difference in urinary porph-
yrin patterns, and no cases of overt porphyria cutanea tarda
(PCT) or any precursor conditions (latent PCT or Type B porph-
yria) were detected.
There appeared to be a trend of increased urinary tract prob-
lems among the high-risk cohort on the basis of the medical
history section of the questionnaire, although no statistically
significant differences were demonstrated. Urinalyses also sug-
gested a consistent pattern of abnormal findings, with a non-
statistically significant higher prevalance of pyuria ( > 5 WBC/
hpf) and microscopic hematuria ( > 3 RBC/hpf) in the high-risk
group.
The potential health effects considered in this study were based
primarily on the animal toxicology of dioxin and results from
studies of long-term industrial and accidental acute human ex-
posures. These analyses did not produce any firm indications of
increased disease prevalence directly related to the putative ex-
posure. These results did, however, offer some insights and leads
for further study. Of interest was the trend indicative of urinary
tract abnormalities in the high-risk group (especially in light of the
previously reported finding of hemorrhagic cystitis in an exposed
person). The finding of no significant differences in liver function
was important; however, it was recommended that hepatic func-
tion should be examined in subsequent studies because of other
animal and human toxicologic data suggesting hepatotixic effects
of TCDD. Although none of the findings from the immune func-
tion tests and assays demonstrated statistically significant dif-
ferences, several results were of note such as a slight increase in
relative anergy and an increased prevalence of helper:suppressor
T-cell ratios < 1.0 in the high-risk group, although the functional
tests of the immune system revealed no overall abnormalities.
Further investigation of all of these effects in exposed cohorts was
recommended.
EPIDEMIOLOGIC STUDY
We recently completed a more refined epidemiologic study*
which was planned to test the results of the pilot study. This medi-
cal epidemiologic study of residents of the Quail Run Mobile
Home Park in Gray Summit, Missouri, was conducted between
November 1984 and January 1985 to determine if, and to what ex-
tent, the health of individuals who resided in the park for 6 or
more months was affected. This population was selected for study
because of high levels of dioxin contamination found throughout
the environs of the mobile home park, including inside many of
the homes. We compared these dioxin-exposed participants with
residents from one of three similar mobile home parks that had
been tested and found to have no dioxin contamination. At the
conclusion of the study, there were 154 exposed and 155 unex-
posed participants. These persons were evaluated under a pro-
tocol similar to that used in the pilot study with the addition of
more specific tests of neurobehavioral parameters (World Health
Organization's core battery for field studies of persons potentially
exposed to neurotoxins), quantitative tests of tactile, vibratory
and thermal sensations, and additional laboratory tests (serum
IgG and creatinine assays, urine cultures, assay of cytotoxic
T-lymphocyte production and liver function tests of microsomal
enzyme induction).
The exposed and unexposed groups were comparable with
respect to age; sex; race; tobacco and alcohol usage; use of
pesticides, wood preservatives or professional herbicidal services;
and history of employment that involved contact with chemicals,
electrical transformers or capacitors, or the incineration of plastic
or wood materials. We also found no difference in the exposed
and unexposed subgroups with respect to age and sex. There was,
however, a statistically significant difference between the groups
for both the mean Hollingshead index score for the head of
household (p <".01), which is inversely related to socioeconomk
level, and the participants' educational level (p C.01). Educa-
tional and socioeconomic levels were lower in the exposed group.
There were no statistically significant differences between the
two groups in the number of reports of any diagnosed medical
condition except for the categories "other skin problems" and
"other miscellaneous diseases." The interview permitted open-
ended responses to these questions, and the participants fre-
quently reported non-physician-diagnosed illnesses. No predomi-
nant or statistically significant condition was reported in these
categories. No cases of chloracne, acne in nonadolescent years,
porphyria cutanea tarda, lymphoma, sarcoma or cancer of the
liver were reported. Six persons (2 exposed vs. 4 unexposed)
reported having had cancer; one of the exposed individuals had
the disease diagnosed more than 20 years before first residing at
Quail Run; the other exposed person's cancer was diagnosed 1
year after the person moved to the park. Although not
significantly different, a greater number of the following selected
conditions were reported by the exposed group: nephritis (4 vs. 2),
cystitis (12 vs. 5), gastric ulcer (5 vs. 2), immune deficiency (2 vs.
0) and depression (7 vs. 6). No statistically significant differences
between the two groups were detected for the reported conditions
that we could confirm by our review of the medical records. Par-
ticipants were questioned about their reproductive health since
1971, and no differences were found between the exposed and
unexposed groups in the frequency of meirorrhagia, menor-
rhagia, amenorrhea, infertility, impotence and loss of libido (asked
of males only), fetal deaths, spontaneous abortions and children
with congenital malformations. For two of 14 symptoms, the
prevalence was significantly increased in the exposed group.
These symptoms were: (1) numbness or pins and needles in the
hands or feet and (2) persistent severe headaches; however, no
difference between groups was observed in the proportion of par-
ticipants who sought medical care because of numbness or
headaches.
On physical examination, there was a statistically significant in-
crease in nonspecific dermatitis in the exposed group (16 vs. 2, p
< .01), but no cases of chloracne or porphyria cutanea tarda were
80 HEALTH ASSESSMENT
-------
diagnosed in any individual. Overall, there was no statistically
significant difference between the two groups in general ap-
pearance, blood pressure, heart rate, magnitude of peripheral
pulses, presence of palpable lymph nodes, peripheral neurologic
function or proportion with either hepatomegaly or abdominal
tenderness.
Routine laboratory tests showed the exposed group to have a
statistically significant increased prevalence of elevated white
blood cell (WBC) count. Statistically significant differences of
other hematologic parameters included mean WBC count, ab-
solute granulocyte count and percentage monocytes in the WBC
differential. Categorical comparisons of all parameters of the
urinalysis, including microscopic analysis of the urine sediment,
showed no differences between the two groups. When analyses
were stratified by age group, sex or current menstrual flow in
women, we found no differences in regard to these parameters.
In special laboratory tests, the exposed group had an increased
prevalence of elevated urinary uroporphyrin levels and a
significantly higher mean level of urinary uroporphyrins. In
stratified analyses, similar statistically significant differences be-
tween groups in mean urinary uroporphyrin levels were found
among adults, females, persons reporting no current alcohol con-
sumption and persons with less than a high-school education. No
participant had a urinary porphyrin pattern or elevated level of
total urinary porphyrins indicative of either latent (> 400 jtg/dl)
or overt porphyria cutanea tarda. We found no significant dif-
ference between groups means for triglyceride, HDL-C, im-
munoglobulin G. glucose, albumin, ALT, AST, GGTP, alkaline
phosphatase, glutathione-s-transferase, alanine aminopeptidase,
beta-glucuronidase and 5'-nucleotidase. The mean values for
serum cholesterol, creatinine and bilirubin were statistically dif-
ferent, the value for the unexposed group being higher than that
for the exposed group for each of these variables. Multivariate
regression analyses using number of years of residence in the park
as a surrogate for dose of TCDD showed a statistically significant
positive relationship with AST, ALT, GGTP, alanine aminopep-
tidase and beta-glucuronidase.
Evaluation of delayed-type hypersensitivity skin tests (DTK)
revealed significantly decreased responses in exposed participants
compared to those who were unexposed. Exposed subjects had a
smaller mean number of positive skin tests and decreased average
induration than the unexposed group. Subgroup analyses showed
that both male and female children had a significantly smaller
mean number of positive skin tests. The mean average induration
was smaller for exposed children of both sexes, but the difference
was statistically significant only for females. For the adult sub-
groups, the only statistically significant difference was that ex-
posed females reacted to a smaller number of antigens, although
both male and female adults tended to have decreased average in-
duration compared with unexposed adults.
A greater percentage of exposed participants were anergic
(defined as no positive reactions to any of the seven standard an-
tigens) compared to the unexposed subjects; no children in the
unexposed group were anergic. Although the mean induration
was significantly less in the exposed group for only two of the
seven antigens (streptococcus and Candida), the frequency of no-
measurable-cutaneous-response was significantly greater in the
exposed group for all antigens but tuberculin and trichophyton.
In addition to the increased frequency of anergy in the exposed
group reported above, a greater percentage of the exposed than
the unexposed participants had at least one abnormal immune
test or at least two abnormal immune tests. The exposed group
had a significantly greater proportion with at least one in vitro
immune test abnormality and non-statistically significant in-
creased frequencies of abnormal T-cell subset tests, a T4/T8
ratio < 1.0 and an abnormality in the functional T-cell tests.
Specifically, the results of T-cell surface marker analyses
showed statistically significant decreased percentages of T3, T4
and Til cells in the exposed group, but the mean number of
each of the T-cell subsets was comparable between groups. B-
cell counts were not directly measured, but the number of non-T
peripheral lymphocytes was calculated and found to be signifi-
cantly greater in the exposed group. In vitro T-cell function was
assessed by lymphoproliferative responses to three mitogens and
tetanus toxoid antigen and CTL activity. Exposed individuals had
comparable lymphoproliferative responses to stimulation with
phytohemagglutinin, conconavalin A and tetanus toxoid, and
they also had a statistically significantly increased response to
pokeweed mitogen. The difference in CTL activity between the
two groups was not statistically significant.
On the neurobehavioral tests, the mean score for the exposed
group was lower (i.e., in the direction of abnormality) than the
score for the unexposed group of 7 of 10 of the Wechsler intelli-
gence and memory scales. However, a statistically significant
(p<".05) difference between groups in aggregate mean scores
was demonstrated for only the vocabulary subtest of WAIS-R by
using analysis of covariance.
Statistically significant differences between groups were found
in the tension/anxiety and anger/hostility scales of the POMS
inventory with higher (i.e., in the direction of abnormality) mean
scores in the exposed group. In addition, the mean scores of the
exposed group were higher than those of the unexposed group
for the depression/dejection and fatigue/inertia scales, although
these differences were not significant. There were no statistically
significant differences between groups on the Trailmaking A and
B, grip strength and simple reaction time tests. The exposed
group, however, consistently took longer to complete the tests
and made more errors in the Trailmaking tests.
Finally, for the neurosensory tests, we compared the thres-
holds of the two groups for each digit on both the tactile and
thermal sensory tests. There were no differences in mean thres-
hold scores.
The findings from this study suggest that long-term exposure
to TCDD may have adverse consequences. TCDD exposure was
associated with depressed DTK responses, anergy and in vitro
immune abnormalities; however, in view of the absence of sig-
nificant differences in reports of clinically diagnosed immune
suppression and prolonged or repeated infections, the abnormal-
ities found in this study should be considered subclinical. It will
be important to follow those individuals who were anergic to de-
termine if their cellular immune function recovers or they develop
clinical disease and to study immune function in individuals with
known body burdens of TCDD. Similarly, it was recommended
that the evidence suggestive of subclinical alterations in liver func-
tion among the exposed participants be further investigated.
Tests to investigate immune function (delayed type hypersensi-
tivity on in vitro testing) are currently under way.
It is important to keep in mind that those studies were carried
out on self-selected populations. There likely were other exposed
individuals who declined to participate in these studies. The effect
of having a self-selected population isn't known.
ON-GOING STUDIES
Since there is little information on the adverse reproductive
outcomes related to long-term environmental exposure to dioxin
such as might occur after repeated direct contact with contam-
inated soils in Missouri, another on-going study is designed to
provide information to determine if such exposure increased the
incidence of malformations, fetal deaths, low-birth-weight bab-
ies and infant mortality. The exposed group will consist of all
HEALTH ASSESSMENT 81
-------
babies born between January 1, 1972 and December 31, 1982, for
whom the residence address of the mother is close to documented
areas of dioxin contamination; there are approximately 400 such
babies. The outcome data (based on a review of medical records
of newborns) for this group will be compared to data for approx-
imately 800 babies born near in time at the same hospital as the
exposed babies to mothers whose race is the same and whose age
is within 5 years of the exposed mothers' ages. In addition, a sur-
vey of all hospitals in the state for malformations diagnosed in
infants by the age of 1 year will be conducted in order to provide
information for baseline reference and for updating the medical
records review of exposed and matched unexposed babies. The
study began in July 1985 and is expected to be completed by late
1986.
Research into characterizing TCDD body burden measure-
ments was designed to study dioxin levels in adipose tissue and
serum from persons exposed to dioxin at residential and com-
mercial sites in Missouri. Volunteers underwent excision of 20 g
of adipose tissue by a plastic surgeon working on contract for the
Missouri Department of Health. Tissue specimens also were ob-
tained from volunteers who had no known exposure to dioxin.
These specimens from "unexposed" persons will comprise a
matrix based on age, sex, race and residence location. Testing
of specimens from the first 97 persons tested (39 exposed and 58
unexposed) are under way. Measurement of TCDD in adipose
provides a much improved measure of exposure which is impor-
tant for studies evaluating the possible health effects of this com-
pound.
A study currently is underway in Missouri to collect blood from
persons who have donated adipose samples for the purpose of
developing a serum test of 2, 3, 7, 8-TCDD. If such a test can be
developed, then a surgical procedure will no longer be needed to
determine exposure to 2, 3, 7, 8-TCDD. With such a test, it also
will be possible to carry out studies to determine the half-life of
2, 3, 7, 8-TCDD in man. A drawback to the serum test is that the
current laboratory method requires 200 to 250 ml of serum.
We also are conducting medical tests on persons who think they
have been exposed to 2, 3, 7, 8-TCDD to see if they have immu-
nologic or other abnormalities.
Finally, CDC, the state Departments of Health and other agen-
cies (such as the Agency for Toxic Substances and Disease Regis-
try) will continue to review environmental data from dioxin-con-
taminated sites in Missouri to establish or update health advisor-
ies. Furthermore, all involved public health agencies will con-
tinue to provide health education about dioxin exposure to the
medical community and the general public.
CONCLUSIONS
In conclusion, collaborative studies between the Missouri De-
partment of Health and the Centers for Disease Control (funded
by the U.S. EPA and the Agency for Toxic Substances and
Disease Registry) have been carried out for the past 4 years. Tests
have been developed which show that a variety of persons have
been exposed to 2, 3, 7, 8-TCDD in recreational, residential or
occupational settings. Some immunologic and liver abnormali-
ties have been identified in persons with 2, 3, 7, 8-TCDD ex-
posure. It is unclear whether these abnormalities are markers of
exposure, biochemical effects or precursors to future disease.
Now that we can measure 2, 3, 7, 8-TCDD in the adipose tissue of
persons, we can determine objectively which persons actually
have been exposed to 2, 3, 7, 8-TCDD.
Research in these areas will continue in order to develop a more
complete understanding of the risks and appropriate public health
interventions in situations of community exposure to environ-
mental dioxins. However, public health policy must continue to
be focused on the prevention of potential health effects, even if
such effects are not yet fully understood. For this reason, all ap-
propriate efforts need to be made to prevent human exposure.
Table 1
Major Milestones In the History of Dioxin In Mlwourl
1971
• Roads, arenas, parking lots sprayed with waste oils throughout
Missouri
• Deaths of rodents, birds, horses in three Missouri horseback riding
arenas
• Child presents with hemorrhagic cystitis
• Epidemiologic investigation implicated oil spraying but specific agent
could not be identified
1974
• Oil residue analyzed, 2,3,7,8-TCDD identified at levels of 33,000 ppb
in riding arena
• Recommendations to clean up the sites is tempered by the belief that
environmental half-life is 6 months
1982
• Resampling at known contaminated sites shows 2,3,7,8-TCDD to be
still present
• EPA and Missouri DNR initiate extensive evaluation of approximately
250 sites
• CDC and Missouri Department of Health reinitiate health investi-
gation
• Times Beach is evacuated after extensive contamination is found in
soil
1983
• Pilot study
• Central Listing set up
• Chloracne screening clinic
• Follow-up epidemiologic study recommended
Quail Run Study begun
1984
1985
Quail Run Study finished
Missouri Adipose Study begun
Reproductive Outcome Study begun
1986
Quail Run Study results published
Follow-up of Quail Run Study participants with immunologic ab-
normalities carried out
Initial results of Adipose Study released
ACKNOWLEDGMENT
These studies were carried out by cooperative agreement with
the Missouri Department of Health. They were supported in part
or whole by funds from the Comprehensive Environmental
Response, Compensation, and Liability Act trust fund by in-
teragency agreement with the Agency for Toxic Substances and
Disease Registry, U.S. Public Health Service.
REFERENCES
1. Carter, C.D., Kimbrough, R.D., Liddle, J.A., etal.. "Tetrachlorodi-
benzodioxin: an accidental poisoning episode in horse arenas," Sci-
ence 188, 1975, 738-740.
2. Stehr, P.A., Forney, D., Stein, G., et al., "The public health response
to 2,3,7,8-TCDD environmental contamination in Missouri," PwWtr
Health Reports, 100, 1985, 289-293.
3. Kimbrough, R.D., Falk, H., Stehr, P., el al., "Health implications
of 2,3,7,8-tetrachlorodibenzodioxin (TCDD) contamination of resi-
dential soil." J. Tax. Env. Health, 14, 1984, 47-93.
82 HEALTH ASSESSMENT
-------
4. Stehr, P.A., Stein, G.F., Webb, K., et al., "A pilot epidemiologic 6. Hoffman, R.E., Stehr-Oreen, P.A., Webb, K.B., et al. "Health ef-
study of possible health effects associated with 2,3,7,8-tetrachlorodi- fects of long-term exposure to 2,3,7,8-tetrachlorodibenzo-p-di-
benzo-p-dioxin contaminations in Missouri," Arch. Environ. Health oxin," JAMA, 255 1986, 2031-2038.
41, 1986, 16-22. 7 Patterson> DG Jr _ Hoffman, R.E., Needham, L.L., Bagby, J.R.,
Pirkle, J.L., Falk, H., Sampson, E.J., Houk, V.N., "Levels of 2,3,7,
5. Knutsen, A.P., "Immunologic effects of TCDD exposure in hu- 8-Tetrachlorodibenzo-p-dioxin in Adipose Tissue of Exposed and Un-
mans," Bull Environ Contam Toxicol 33, 1984, 673-681. exposed Persons in Missouri," (manuscript submitted).
HEALTH ASSESSMENT 83
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A National Study of Site Discovery Methods
Margie Ortiz
Francis J. Priznar
Booz, Allen & Hamilton Inc.
Bethesda, Maryland
Paul Beam
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Washington, D.C.
ABSTRACT
Under contract to the U.S. EPA, Booz, Allen & Hamilton Inc.
conducted a national study of methods for discovering potential
hazardous waste sites. The study was conducted by interviewing
U.S. EPA staff in Headquarters and in Regional offices, selected
staff of States that have a range of site discovery programs, and
firms under government contract that have site discovery
responsibility.
Our findings indicate a large variety of possible site discovery
mechanisms. Further, a large number of industries that are poten-
tial site producers are identified. A preliminary analysis was carried
out to subjectively compare financial, capture efficiency and
administrative elements of site discovery mechanisms. The results
of the analysis can be used to direct effective approaches to site
discovery.
INTRODUCTION
Interest in conducting a study of site discovery program needs
has arisen because of congressional inquiry, proposed Super fund
reauthorization language and a Mar. 26,1985, General Accounting
Office report, titled, "EPA's Inventory of Potential Hazardous
Waste Sites is Incomplete."
Discovery and identification of releases or threatened releases
of hazardous wastes have been reported to the U.S. EPA through
the 103(c) program and a large variety of other mechanisms across
the country. These include: State government investigation; selected
facility inventories; random Federal, State and local government
agency observation: informal private observation; and reporting
of present hazardous waste operations under RCRA. These
methods are presently part of the discovery program.
The exact magnitude of the uncontrolled hazardous waste
problem on a national level remains unknown. This uncertainty
may result in inaccurate determinations of the amount of resources
ultimately needed to understand and remedy the problem. Analysis
of current discovery methods could result in program changes that
will better forecast future U.S. EPA, State or private resources
and schedules to meet Superfund's comprehensive objectives.
The overall objectives of this phase of the project were to:
• Develop an understanding of the current status of nationwide
site discovery activities
• Prepare conceptual options and determine requirements for a
proactive nationwide site discovery program
This paper is organized in four sections. First, a discussion of
the approach for the study is presented. Second, the study findings
are summarized and discussed. Third, a comparison of the various
site discovery mechanisms using financial, capture efficiency and
administrative criteria to understand the relative advantages of
various site discovery mechanisms is made. Finally, some con-
clusions are made and particular areas of importance are noted.
APPROACH
Site discovery program information was collected by two
methods: telephone inquiries and personal interviews. The
telephone inquiry was conducted in order to understand current
approaches to discovery activities throughout the country and to
identify specific discovery mechanisms. Regional U.S. EPA staff
and State personnel with CERCLA responsibility were interviewed.
An interview guide was used during the telephone inquiries. The
first questions provided an understanding of Regional or State goals
in site discovery and the status of current programs. Additional
questions were asked about the types of industries present in the
State usually associated with the existence of hazardous waste sites.
The remaining questions addressed the need for prescreening site
information by the States, the existence and status of a State data
base and the compatibility of the data base with CERCLA Infor-
mation System (CERCLIS). Prescreening is a term used for any
cursory analysis of sites by a State to determine whether or not
a site will be entered into CERCLIS.
At least one person from each U.S. EPA Regional office was
interviewed. Further, staff from 40 different State agencies were
interviewed; about 80% of the States in each Region were
contacted. Both U.S. EPA Regional and State staff were asked
to provide information on their contractors' activities related to
site discovery.
The second method used for collecting information consisted
of developing a more in-depth understanding of site discovery
activities through in-person interviews. Region V and its consti-
tuent States were selected for these interviews because of the large
number and diversity of sites within the Region. Questions similar
to those in the telephone interviews were asked. In addition, group
discussion among the participants allowed opinions and attitudes
toward a potential site discovery program to be discussed in more
detail and at greater length than in a telephone interview.
FINDINGS
Information gathered during the telephone and in-person inter-
views is presented in this section. A synthesis of this information
serves to detail current site discovery activities and identifies indus-
tries of actual and potential CERCLIS concerns. Highlighted in
our findings are administrative, legislative and technical aspects
of site discovery activities. Included are summaries of:
• Site discovery-related characteristics of state wide programs
• Site discovery mechanisms
84 SITE DISCOVERY & ASSESSMENT
-------
Industries or activities likely to result in hazardous waste sites
SITE DISCOVERY MECHANISM
Figure 1 presents site discovery-related characteristics of State
programs for States participating in the study. The darker part of
each pie chart indicates the percent of affirmative responses to the
interview questions. For example, 40% (16 out of 40) of the States
interviewed had proactive site discovery elements in their CERCLA
programs; these 16 States were evenly distributed throughout the
country; thus, the existence of a proactive program did not seem
to be influenced by geographic location.
» PARTICIPATING STATES WTTH PROACTIVE
SITE DISCOVERY ACTIVITIES
% PARTICIPATING STATES HAVING
SUPEKFUND TYPE LEGISLATION
* PARTICIPATING STATES WITH
HAZARDOUS WASTE SITU DATA BASE
% PARTICIPATING STATES WITH
DATA BASE COMPATIBLE TO CERCLIS
LEGEND
H YES
H NO
« PARTICIPATING STATES THAT PRESCREEN
SITES BEFORE ENTRY INTO CERCUS
Figure 1
Site Discovery Related Characteristics of State Programs
Fifteen of the 40 States interviewed had hazardous waste site
databases. Eight of these States had their own "Superfund-type"
legislation which provided impetus for site discovery activities. Only
one State with the legislation did not mention having a data base
in the interview. A hazardous waste site data base was found in
seven States with no local legislation. Except for Region V (greater
than average affirmative answers) and Region IV (fewer than
average affirmative answers), the States with data bases seemed
to be evenly distributed among the Regions.
The criteria used for entry of sites into each State data base varied
greatly. The information contained in existing data bases was found
to be inconsistent. It varied in type and description of sites included.
In addition, the level of effort used to create and maintain the data
base was different, which resulted in different depths of coverage
of potential sites.
Only two States with a data base have systems compatible (i.e.
containing information about the same sites) with the CERCLIS
data base. State data bases may have sites that could have been
included in the CERCLIS data base as well as sites not included
in the Superfund definition of a hazardous site. For example, they
might include sand and gravel operations, salt water intrusion sites,
sites containing petroleum and other substances excluded from
Superfund. They also may have omitted sites included in
CERCLIS. In the former case, better use of existing information
CITIZEN COMPLAINT
REFERRALS - OTHER
STATE AGENCIES
PA/SI WORK BYPRODUCT
REFERRALS - OTHER BRANCH
OF ENVIROMENTAL AGENCY
HISTORIC SEARCH AND
FILE REVIEW
REFERRALS - OTHER
INSPECTIONS
SOLICITATION OP
INFORMATION
SURVEY REVIEW
PROPERTY TRANSFER
REGULATIONS
SPILLS
(EMERGENCY ACTION)
REMOTE SENSING
INDUSTRIAL
CLASSIFICATION FILE
REPORTING BY
COMMERCIAL INTERESTS
RESPONSIBLE PARTIES
STUDY SELECTED
GEOGRAPHICAL AREA
STODY SELECTED
INDUSTRY
H 1 1 1 r-
H 1 1 1
10 20 30 40 50 60 70 80 90 100
% OF STATES UTILIZING MECHANISM
Figure 2
Frequency of Site Discovery Mechanisms
Utilized by States
could prove to be a method of "discovering" new sites for both
States and CERCLIS.
Initial program guidance in the area of site prescreening can be
found in the 103(c) notification. Forty percent (16 of 40) of the
States surveyed perform a prescreening test to some degree before
the data are entered into CERCLIS. Prescreening criteria are
selected by each State according to its own needs and priorities.
The U.S. EPA neither reviews nor approves the prescreening
activities of individual States.
Prescreening of potential sites has several implications for the
Superfund process. Prescreening by States can reduce the number
of ineligible sites that are reported to CERCLIS and decrease costs
associated with further pre-remedial investigation. Conversely, if
State prescreening criteria are not in agreement with Superfund
requirements, some sites may be prematurely disqualified, thereby
increasing future Superfund costs.
Figure 2 presents a summary of site discovery mechanisms which
emphasizes the variety of ways in which sites presently are
discovered by the States. Because the data used to prepare this
figure were collected through one or two interviews per State, it
is likely that the frequency of each mechanism used was
underestimated. For example, States that mentioned only one or
two mechanisms may, in fact, utilize more. Other possible
mechanisms such as some types of historical searches (trade associa-
tion information, the telephone directory, trade journals, etc.) were
not mentioned at all.
Citizen complaints, site identification through Preliminary
Assessment/Site Inspection (PA/SI) work, referrals by State
agencies and other, unrelated types of inspections were some of
the most frequently mentioned mechanisms. These methods are
classified as passive since they do not require Regions or States
to make a concerted, organized effort to obtain the information.
The information is volunteered or funneled through various
channels until it comes to the attention of the U.S. EPA. On the
other hand, active mechanisms are those in which purposeful
actions are undertaken to obtain new sites. Examples of these are
SITE DISCOVERY & ASSESSMENT 85
-------
historical searches, solicitation of State agencies and special projects
such as an industry-based survey.
The aforementioned passive mechanisms were reported most
frequently for several reasons: they can function with a limited
Site Discovery Program; they are low cost and require no capital
or overhead expenses. Some active mechanisms function at pre-
sent in several States. However, usually only those States with
Superfund type legislation and local data bases are likely to know
about and/or use active mechanisms.
COMPARISON OF SITE DISCOVERY MECHANISMS
A preliminary analysis was made to subjectively compare the
relative advantages and disadvantages of implementing the site
discovery mechanisms suggested by the telephone interviews. The
analysis compared financial, capture efficiency and administrative
elements of the site discovery mechanisms.
In Table 3, a matrix of selected site discovery mechanisms versus
critical elements was used. Numbers ranging from - 2 to + 2 were
assigned to the variables to indicate their relative desirability (from
least to most desirable, respectively). Comparing the totals of the
horizontal rows allowed the mechanisms to be ranked according
to their relative desirability.
Table 1
Relative Desirability of Selected Site Discovery
Mechanisms by Numeric Values
CHITICAI.
ELEVEN!!
POM EFA
•ITf
OUCOVEffV
MECHANISM
FINANCIAL
CAPTURE EFFICIENCY
ill 1!
In this approach, a weighting factor could be used to allow any
specific mechanisms or critical elements to be given more or less
relative importance. By using this process, selected elements that
may strongly influence site discovery mechanism selection could
be taken into account. For example, cost may be considered to
have a greater negative impact than other elements in decision-
making, therefore it would be multiplied by a factor greater than
that of the other elements.
For decision-making purposes, the comparison of various
versions of the analysis, with the application of different weighting
factors or different combinations of the weighting factors applied
to the mechanisms or elements, would aid in the selection of
mechanisms for a site discovery program. For purposes of this
report, no weighting factor was used for any mechanism or critical
element.
For this analysis, site discovery mechanisms were put into three
groups: passive, active and special studies. Passive mechanisms are
defined as actions that occur with minimal organized efforts by
the U.S. EPA or States doing Superfund work. In this group, EPA
primarily receives unsolicited information from sources external
to CERCLA such as interested private parties, referrals or as a
result of activities under other laws and regulations. Only where
additional sites were discovered as PA/SI by-products would the
U.S. EPA and the States' CERCLA programs be directly involved
in producing the information.
Active mechanisms are those that involve planning and direct
costs to the U.S. EPA and the States. Since referrals, PA/SI by-
products and responsible party reporting are mechanisms that may
be passively or actively encouraged, they are included in both the
active and passive groups.
Special studies, such as geographic area or industry-specific
studies, are highly organized efforts with well defined objectives,
methods and timeframes. They may be instituted on a national,
regional or local scale.
The critical elements used to compare the mechanisms are also
divided into three categories: financial, capture efficiency or
administrative. The first two elements may be defined subjectively
or mathematically; the third is very difficult to rigorously define.
The financial elements are the various monetary costs associated
with the mechanisms. Capture efficiency elements are those related
Table 2
Preliminary Ranking of Site Discovery Mechanisms
By Financial, Capture Efficiency, and Administrative Critical Dental
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86
SITE DISCOVERY & ASSESSMENT
-------
to the end result of mechanism utilization. The last category,
administrative elements, indicates the relative difficulty in imple-
menting each mechanism from a management and institutional
standpoint.
The results of the model, although qualitative, can be used to
formulate initial positions on the relative desirability of imple-
menting selected mechanisms and as a focus of discussion for the
evaluation of specific critical elements related to the mechanisms.
Although the information presented in Figure 4 is preliminary, it
is included to present its potential application to site discovery
decision analysis.
Ordering these totals from highest (1) to lowest (10) rank gives
the most to least desirable site discovery mechanism. Table 4
presents the ranking of site discovery mechanisms. The first column
is the overall ranking, based on the summation of all the factors
composing the critical elements. It is not based on a summary of
the other rankings. The mechanisms are listed according to the
overall ranking from most to least desirable. The results vary
according to the critical element used to rank. This division of
decision criteria allows a separate evaluation of each element. In
future iterations, it would be simple to revise the factors included
in each element or add relative weightings to them.
CONCLUSIONS
In this report, information was presented about background
characteristics of State programs related to site discovery,
mechanisms for discovery utilized by the States and industrial types
that are potential sources of hazardous waste sites. One type of
decision analysis that compares site discovery mechanisms to
financial, capture efficiency and administrative elements provided
a preliminary ranking.
The findings suggest that passive mechanisms (with the exception
of responsible party reports) are the most desirable because they
cost less than active mechanisms, produce positive results and
function with or without a formal program. These mechanisms
can be formalized through development of guidance at a relatively
low cost.
Studies, especially of a selected industry, should be given further
consideration as a potential method of discovering new sites because
of its high capture efficiency and administrative rankings.
SITE DISCOVERY & ASSESSMENT 87
-------
The Difficulties of Modeling Contaminant Transport
At Abandoned Landfill Sites
Mark D. Taylor, P.E.
Camp Dresser & McKee Inc.
Atlanta, Georgia
ABSTRACT
The role of contaminant transport models in remedial investi-
gations and feasibility studies for hazardous waste sites is to assist
in formulating appropriate questions concerning the remedial
planning and design activities for the site and to help obtain quan-
titative answers of sufficient accuracy and detail to guide remed-
ial action at the site. The problem of developing a contaminant
transport model which can produce quantitative answers of
sufficient accuracy and detail usually is difficult due to the lack
of information about the contaminant transport properties of the
subsurface environment as well as the attenuation properties of
the contaminants. This problem becomes even more difficult
when trying to simulate contaminant movement at abandoned
landfill sites. Not only is information about the above proper-
ties scarce, but also little or no information often is available
about the amounts of contaminants released into the environ-
ment and/or when they were released.
The most useful models are those that have been calibrated
and verified. Traditionally, calibration of a contaminant trans-
port model involves comparing concentrations of contaminants
measured in the field to those predicted by the model for a given
historical spill or release event and then adjusting the contami-
nant transport parameter values so that model results more close-
ly reproduce the measured concentrations. Calibration thus
requires a reasonable estimate of the contaminant loading rate(s)
for each source at the site. Unfortunately, at abandoned land-
fill sites, there usually are not enough data to make a reasonable
estimate of past, present or future contaminant loading rates.
There are few records, if any, indicating what and how much
waste was deposited at the site, let alone when and at what rate
contaminants were released into the environment. When histori-
cal data are not available, it sometimes is possible to estimate
average contaminant loading rates based on the contaminant
plume concentrations measured in the field. It is imperative,
however, that the contaminant plume be well defined in these
cases.
The inability to calibrate a contaminant transport model does
not make contaminant transport modeling useless in abandoned
landfill site investigations. Although calibrated models are more
useful than uncalibrated models, certain measures can be taken
to obtain useful information from uncalibrated models. Ranges
of values for the contaminant transport parameters can be esti-
mated based on previous modeling studies and research. Model
results for given scenarios then can be investigated over those
ranges of values. In this capacity, the model can be used to pre-
dict ranges of contaminant migration. The results then may be
used to increase understanding of the contamination problem
and thus help guide the risk assessment and decision-making
process for remedial action at the abandoned landfill site.
INTRODUCTION
The use of contaminant transport models in hazardous waste
site investigations is becoming more common. More investigators
are discovering how useful these models can be in guiding remed-
ial action at hazardous waste sites where groundwater has been
contaminated. In addition, more groundwater professionals are
becoming proficient in their use, thus increasing the number and
percentage of successful model applications. With this increase
in model use comes an increase in understanding the contam-
inant transport processes in groundwater systems as well as an
increase in knowing hou to apply these models at various sites.
Like any other discipline, the groundwater profession learns from
its accomplishments and its mistakes.
The purpose of this paper is to relay some of the author's
knowledge and experience to the groundwater profession by dis-
cussing some of the difficulties of modeling contaminant trans-
port, particularly at abandoned landfill sites. Before anyone can
understand these difficulties, however, one must first understand
the roles of contaminant transport models in hazardous waste
site investigations as well as the process or approach taken to
develop a useful model. The first two sections of this paper are
thus devoted to these topics.
THE ROLE OF CONTAMINANT
TRANSPORT MODELS
The role of contaminant transport models in remedial investi-
gations and feasibility studies for hazardous waste sites is to help
formulate appropriate questions concerning the remedial plan-
ning and design activities for the site and to help obtain suffic-
iently accurate and detailed quantitative answers to guide remed-
ial action at the site. The role of these models is not to provide
precise answers to the questions posed but rather to produce re-
sults which will guide the decision-making process. Contaminant
transport models are tools that can aid the study of groundwater
contamination problems and can help increase understanding of
the groundwater system. Just as an X-ray machine is a tool which
helps doctors examine the internal parts of the human body, a
contaminant transport model is a tool which helps scientists and
engineers evaluate the internal constituents of the groundwater
system. Both enable the professional to evaluate the problem
without actually having to see it, and both provide results which
require interpretation by a professional who understands the
tool's limitations. Unfortunately, for the groundwater profes-
sional, contaminant transport models have many more limita-
tions than X-ray machines, some of which are discussed in this
paper. In spite of the limitations, however, contaminant trans-
port models, when developed and used properly, do provide the
most technically sound results on which decisions regarding
groundwater remediation can be based. Contaminant transport
88
SITE DISCOVERY & ASSESSMENT
-------
models thus eliminate the necessity to base groundwater remed-
iation decisions solely on intuition and past experience.
Contaminant transport models can perform three valuable
functions when investigating a groundwater contamination prob-
lem: organized representation, knowledge amplification and com-
parative evaluation. These three functions are discussed below.
Organized Representation
One of the major problems encountered in remedial planning
or design for many hazardous waste sites is to represent and dis-
play in simple and consistent terms the numerous characteristics
of the groundwater system. The hydrogeologic data collected for
most sites are marginally useful in their raw form and need to be
organized in some fashion to provide a simple but complete pic-
ture of the system. Contaminant transport models provide a
means for the representation of such systems, whether simple or
complex, and for actually carrying out much of the computation
required for this organization.
Knowledge Amplification
When properly developed and used, contaminant transport
models can amplify available knowledge of the behavior of a
groundwater system. Contaminant transport models do not pro-
duce new data but do permit the extraction of greater amounts
of information from the existing data base. They can be used to
simulate past or present conditions, or they can be used to pre-
dict future conditions. In this sense, contaminant transport mod-
els increase the understanding of the problem and of the possible
solutions.
Comparative Evaluation
Contaminant transport models can be developed to produce
measures of performance of the groundwater system in response
to different stresses or actions. These measures of performance
then can be used in the comparative evaluation of the various
actions. For instance, at most hazardous waste sites, the future
contaminant attenuation and migration patterns under several
remedial action alternatives need to be evaluated. These remed-
ial action alternatives may include:
Natural flushing/no action
Accelerated flushing using additional recharge
Source removal such as excavation
Plume containment by hydraulic measures such as pumping
Plume containment by physical measures such as slurry walls
Plume extraction using pumping
Contaminant transport models can project or predict the con-
sequences of these actions in terms of time and effectiveness.
These predictions then can be used as a basis for comparing the
remedial action alternatives. Of course, other factors such as cost
and implementability should be considered, too, before selection
of the "best" remedial alternative is made for the site.
Contaminant transport models represent the behavior and per-
formance of the complex real world aquifer system and there-
fore are very powerful analytical tools. Because of their useful-
ness, they play a very important role in remedial investigation
and feasibility studies for hazardous waste sites. However, they,
like most models, are an approximation of the real world system
and are not completely equivalent to the real world in all aspects.
The worst possible misuse of a contaminant transport model is
blind faith in model results.
nique selection, data preparation, calibration, verification and
prediction. These tasks should not be considered separate steps
of a chronological procedure but instead should be considered
as an iterative procedure where each step results in feedback of
how the "new knowledge" obtained fits with what was previous-
ly known about the site. Often, changes in the modeling tech-
nique or the level of detail are necessary as model development
proceeds. For this reason, a clear objective of the study is re-
quired before the study can begin.
System Conceptualization
Development begins with a conceptual understanding of the
physical system. Since simulation of a groundwater system re-
fers to the development and operation of a model whose behavior
assumes the appearance of or approximates the actual system's
behavior, it is imperative that the modeler have at least a basic
understanding of the physical behavior of the actual system. The
general cause-effect relationships must be identified. For ground-
water flow, these relationships usually are known and are ex-
pressed in terms of hydraulic gradient and flow directions. For
the movement of contaminants, these relationships usually are
only partially understood but are expressed in terms of plume
attenuation or migration.
SYSTEM
CONCEPTUALIZATION
DATA
COLLECTION
SOLUTION
TECHNIQUE
SELECTION
DATA
PREPARATION
MODEL
CALIBRATION
MODEL
VERIFICATION
PREDICTION
MODELING APPROACH
The development of a contaminant transport model for a haz-
ardous waste site investigation involves several areas of effort.
These areas are outlined in the flow diagram shown in Fig. 1 and
include: system conceptualization, data collection, solution tech-
Figure 1
Modeling Approach
SITE DISCOVERY & ASSESSMENT 89
-------
Data Collection
All available hydrogeologic and analytic data need to be com-
piled, reviewed and assimilated for the site. These data include
but are not limited to:
• Boring logs which identify the various geologic formations
• Aquifer performance, slug, tracer, and laboratory test results
which are used to determine aquifer properties
• Climatic data such as rainfall and evaporation rates
• Water level measurements
• Water quality measurements
• Streamflow measurements
• Contaminant source characteristics such as mass loading rates
into the aquifer system
The amount of data needed depends on the complexity of the
site, the level of detail required and the desired reliability of model
results. An extensive field program, normally included as part of
a remedial investigation, may be needed to collect all the neces-
sary data. At many sites, however, important data may be too
costly or even impossible to collect. In these cases, the data gaps
have to be filled with assumed values. These assumptions directly
affect the reliability of the model results. The reliability of the re-
sults also is influenced by the quality of the data collected. Mod-
elers must, therefore, never overlook the data collection step as
being trivial, for insufficient or bad data will limit the usefulness
of their models. The old adage "garbage in, garbage out" is all
too possible in contaminant transport modeling.
Solution Technique Selection
A wide variety of solution techniques presently are being used
by groundwater professionals to solve contaminant transport
problems. These techniques range from simple one-dimensional
analytical solutions to complex three-dimensional numerical solu-
tions. Physical and electrical analog models have been used in the
past, but today these types of models generally are considered
archaic. The choice of the solution technique depends on several
factors: the objective of the study, the complexity of the site,
the amount of data and the desired reliability of model results.
The choice of the solution technique should be left to the exper-
ienced modeler who knows the advantages, disadvantages and
limitations of each technique.
Data Preparation
Data preparation for contaminant transport models first in-
volves determining the physical and artificial boundaries of the
region to be modeled. Physical boundaries are those that actual-
ly take shape in the form of some hydrogeologic feature and
for all practical purposes will not move. Examples of physical
boundaries are impervious geologic formations such as bedrock
(no flow boundary) and constant head sources or sinks such as
rivers or springs (constant head boundary). Artificial boundaries
are those that occur in the environment under a certain set of
conditions but which move or change if the conditions change.
For obvious reasons, artificial boundaries need to be set far
enough from the site so that any conditions imposed at the site
will not significantly impact the boundary. An example of an
artificial boundary is a groundwater divide (no flow boundary).
Once the boundaries have been defined, a coordinate system
must be set up. For numerical models, the region must be sub-
divided into a grid system. Depending on the numerical proced-
ure, the grid may have rectangular or polygonal shaped sub-
divisions. For three-dimensional models, the vertical dimensions
also must be subdivided. This step generally involves defining
the elevations of each hydrogeologic unit across the model area.
After the coordinate system or grid system has been laid out,
values for the aquifer properties and stresses as well as contam-
inant attenuation properties are specified. For numerical modeli,
values must be assigned to each subdivision. For most practical
problems, aquifer properties, aquifer stresses and chemical atten-
uation properties include:
Horizontal and vertical hydraulic conductivities
Storage coefficients or specific yields
Effective porosities
Longitudinal and transverse dispersivities
Retardation factors
Biological/chemical decay rates
Pumping rates
Rainfall recharge
Contaminant source loading rates
The last step in preparing data for the contaminant transport
model is specifying the initial conditions. Starting water level ele-
vations and contaminant concentrations are needed to begin
modeling.
Calibration
Before a contaminant transport model is used as a predictive
tool, it should be calibrated to the best extent possible with pres-
ently available data. The most useful models are those that have
been calibrated and subsequently verified. The procedure for cal-
ibration involves selecting past inventory periods where data are
sufficient to investigate the distribution of model parameter!.
Usually, calibration of contaminant transport models is divided
into two phases: groundwater flow calibration and contaminant
transport calibration. Before a contaminant transport model can
be expected to adequately simulate contaminant migration, it
must be able to adequately simulate groundwater movement.
Groundwater flow calibration usually involves comparing
model-generated aquifer water levels to observed aquifer water
levels and performing a sequence of adjustments in the flow
parameter values so that modeled water levels more closely re-
produce observed water levels. Since there are numerous com-
binations of hydrogeologic parameters that can yield similar
aquifer responses, the ranges of parameters used to match his-
toric data are kept within realistic limits. Parameters that are con-
sidered to be least reliable usually are modified more than other
parameters. The primary concern of this process is the global re-
sponse of modeled water levels in both space and time. Although
small areas within the model may not match historical data for
every different hydrologic condition imposed, systematic mis-
matches are investigated and eliminated.
Traditionally, calibration of contaminant transpolrt involves
comparing concentrations of contaminants measured in the field
to those predicted by the model for a given historical spill or re-
lease and then adjusting the contaminant transport parameter
values so that model results more closely reproduce the meas-
ured concentrations. The contaminant transport calibration pro-
cedure is very similar to calibration of groundwater flow. Cali-
bration of contaminant transport, however, requires that reason-
able estimates of the contaminant loading ratc(s) and dura-
tion(s) be made for each source at the site.
No hard and fast rules exist to indicate when a contaminant
transport model is calibrated. The number of test simulations re-
quired to produce a satisfactory match of observed readings de-
pends on the objectives of the study and the complexity of the
site. The point at which a contaminant transport model is consid-
ered to be calibrated is usually left to the judgment of the ground-
water professional.
Verification
The verification process generally is performed to provide addi-
tional assurance that the contaminant transport model is an ade-
90 SITE DISCOVERY & ASSESSMENT
-------
quate representation of the hydrogeologic system. The process
basically consists of using historical data from time periods other
than the calibration time periods as input to the calibrated model
to simulate the associated historical responses. Unfortunately, at
hazardous waste sites, data are usually so scarce that the verifica-
tion process is bypassed. Verification of the groundwater flow
parameters sometimes is possible, but rarely, if ever, is verifica-
tion of the contaminant transport parameters possible.
Prediction
The main purpose of prediction for hazardous waste site inves-
tigations is to estimate the rates and directions of contaminant
movement under various conditions imposed. The fate of the
contaminants if no action is taken is always an interesting pre-
diction. How long it will take to remove the contaminants under
different extraction well schemes is also an interesting prediction.
Generally, the prediction step is used to determine what, if any,
remedial action should be taken at the site.
ABANDONED LANDFILL MODELS
As can be seen in the previous section, developing a useful con-
taminant transport model can be a long, tedious and often diffi-
cult task for any type of hazardous waste site. The amount of
data required to develop a contaminant transport model which
can produce quantitative answers of sufficient accuracy and de-
tail usually is quite extensive. At many hazardous waste sites,
not all the necessary data are available. This makes calibration
very difficult. Among the more difficult sites to model are aban-
doned landfill sites.
At most hazardous waste sites, enough information usually is
available or can be easily obtained to adequately develop and cal-
ibrate the groundwater flow portion of a contaminant transport
model. One exception may be a site where groundwater flows
through fractured or cavernous media. Flow in fractured or cav-
ernous media is an area for which models are not yet well devel-
oped. Groundwater flow in porous media, however, usually can
be modeled without much difficulty. Thus, the difficulties of
modeling contaminant transport at most hazardous waste sites
usually do not arise from a lack of information about the flow
properties of the aquifer system but instead stem from a lack of
information about the contaminant transport properties of the
aquifer system as well as the attenuation properties of the con-
taminants themselves.
The properties in question include:
• Longitudinal and transverse dispersivities
• Retardation factors
• Biological decay rates
• Chemical decay rates
The meanings or definitions of these properties are not impor-
tant to this discussion, and since there are many other references
which explain them quite adequately, they are not discussed.
Contaminant transport is a growing science, and values for the
above properties are not easily measured or determined. There-
fore, these properties usually are considered calibration proper-
ties and initial estimates are obtained from other studies at similar
sites. A great deal of uncertainty emerges, however, when deal-
ing with so many unknown parameters. Because of this uncer-
tainty, calibration is very difficult and generally is performed on
an order of magnitude basis.
The above difficulties in developing a contaminant transport
model are common to all sites. Abandoned landfill sites, how-
ever, have a characteristic which makes contaminant transport
modeling even more difficult. This characteristic may not be
unique, but it is common to most abandoned landfill sites. Not
only is information about the contaminant transport properties
of the aquifer system and the contaminant attenuation proper-
ties scarce, but also many times little or no information is avail-
able about the amounts of contaminants released into the en-
vironment and/or when they were released. As was stated prev-
iously, calibration of a contaminant transport model requires
reasonable estimates of the contaminant loading rates for each
source at the site. In any model study where the properties of the
system are not well defined, simulation of a particular response
and calibration of these properties require that the stress which
created this response be .known. Otherwise, there are too many
unknowns for the model to be calibrated. Therein lies the root
of the problem for modeling contaminant transport at aban-
doned landfill sites. In this case, the contaminant concentrations
in the groundwater system are the response and the contaminant
loading rates are the stress. Unfortunately, there usually are not
enough data to make a reasonable estimate of the past, present or
future stress.
While it is true that there are few, if any, records indicating
what and how much waste was deposited at an abandoned land-
fill site, let alone when it was released into the environment, it
sometimes is possible to estimate average contaminant loading
rates based on the contaminant plume concentrations measured
in the field. The total mass of contaminants released into the
aquifer system can be estimated from the concentrations meas-
ured (allowing for loss due to attenuation). The total time of re-
lease can be estimated by dividing the length of the plume (allow-
ing for dispersion and attenuation) by the average linear flow
velocity. From these two estimates, a crude average historical
loading rate can be calculated. Even for a crude estimate, how-
ever, it is imperative that the contaminant plume be well defined
in terms of the areal and vertical variation in concentration of
contaminants.
Because of the many difficulties inherent in calibrating a con-
taminant transport model for an abandoned landfill site, cali-
bration often is not possible. The inability to calibrate a contam-
inant transport model, however, does not make contaminant
transport modeling useless. Although calibrated models are more
useful than uncalibrated models, certain measures can be taken to
obtain useful information from uncalibrated models.
Ranges of values for the contaminant transport parameters
can be estimated based on other modeling studies and research.
Ranges of contaminant loading rates can be estimated based on
the little information that does exist for the site. If a thorough
analysis is desired, the model results for given scenarios then
can be investigated over all value ranges. In this capacity, the
model can be used to predict ranges of contaminant migration
and concentration at key points.
If only a conservative approach is desired for the study, the
number of simulations can be reduced significantly by only in-
vestigating model results for the worst case conditions of param-
eter values. In this capacity, the model can be used to predict the
worst possible extent of contaminant migration and the worst
possible concentrations of contaminants at key points.
Thus, although an uncalibrated contaminant transport model
cannot indicate or predict with any reasonable degree of relia-
bility the actual fate of contaminants in the groundwater system,
it can predict with a good degree of reliability what can and can-
not happen to these contaminants. These results then may be used
to increase our understanding of the contamination problem and
thus help guide the risk assessment and decision-making process
for remedial action at the abandoned landfill site.
CONCLUSIONS
Contaminant transport models are important tools in haz-
ardous waste site investigations. They can be used to simulate
SITE DISCOVERY & ASSESSMENT 91
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the movement of contaminants in the groundwater system under
many different conditions and thus help guide the decision-mak-
ing process for remedial action at these sites. The development of
these models involves conceptualizing the system, collecting data,
selecting a solution technique, preparing the data, calibrating the
model, verifying the model and finally making the predictions.
Because of the amount of information needed to perform these
tasks, development of a contaminant transport model is usually a
long, tedious and often difficult task.
Among the most difficult sites to model are abandoned land-
fill sites. While most hazardous waste sites are difficult to model
due to the lack of information about the contaminant transport
properties of the aquifer system and the attenuation properties
of the contaminants themselves, abandoned landfill sites have an
added complication; many times there is little or no informa-
tion available about the contaminant source characteristics. With-
out reasonable estimates of contaminant source loading ratej,
the contaminant transport model cannot be calibrated. An un-
calibrated model, however, is not useless. An uncalibrated model
can be used to predict ranges of contaminant migration based
on estimated ranges of contaminant transport parameter values.
These results will help to increase our understanding of the con-
tamination problem which otherwise might have been lacking.
REFERENCES
1. Mercer, J.W. and Faust, C.R., "Groundwater Modeling," National
Water Well Association. 1981.
92 SITE DISCOVERY & ASSESSMENT
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Town Gas Plants—History, Problems
And Approaches to Study
G.J. Anastos, Ph.D., P.E.
G.M. Johnson, P.E.
R.M. Schapot
V.G. Velez
Roy F. Weston, Inc.
West Chester, Pennsylvania
ABSTRACT
Town gas plant sites are receiving increasing attention from the
utility industry and regulatory communities. This attention has been
prompted by greater environmental awareness of impacts due to
past disposal practices and the understanding that gas plant wastes
contain a wide range of chemical constituents that have persisted
in the environment.
This paper discusses the history of the town gas plant industry,
the various processes utilized and the resultant by-products and
wastes. Potential problem areas relating to these sites as well as
potential approaches to site characterization are addressed.
Included are recommendations for the phasing of site investigations
and the use of relatively inexpensive and rapid field screening
techniques to identify contamination.
INTRODUCTION
Town gas plants, utilized throughout the United States in the
late 1800s and early 1900s to manufacture gas for illumination,
cooking and heating purposes, are of growing concern to the utility
industry and regulatory communities. These plants (well over 1,000
across the country), as well as gas storage holders, gas cleanup areas
and waste and by-product disposal areas, are undergoing scrutiny
because of the array of wastes that were generated and/or disposed
of at many of these sites. The wastes commonly found at these
sites can contain heavy metals, cyanides, phenolics, polynuclear
aromatics and volatile compounds. Some of these chemical con-
stituents can be characterized as mobile, while others are persis-
tent in the environment.
This paper discusses the history of town gas plants, the poten-
tial problems posed by town gas plant sites and site characterization
procedures to evaluate these sites. Cost-saving field screening
techniques developed to identify volatiles and polynuclear aromatic
compounds will be discussed.
This paper also will discuss a ranking system that has been imple-
mented successfully to prioritize site characterization at multiple
sites. This system will interest utilities confronted with multiple
site evaluations. In some cases, this ranking system has been used
as a basis for selecting the no action alternative.
HISTORY OF TOWN GAS PLANTS
Town gas plants had their roots in the 1700s with the discovery
that coal carbonization was a major means of producing coal gas,
coal tar, light oils, coke and ammonia liquor. These by-products
were utilized as source materials for the production of various
materials used in diverse industries. Manufactured gas was initially
a major source of fuel for illumination in many cities in England,
Germany and the United States. The uses of manufactured gas
expanded to include those which utilize natural gas today.
In addition to manufactured gas, the use of coal tars and light
oils grew to major importance in the chemical manufacturing
industry. The tars and oils were used as base materials for the
formulation of a variety of products, including paints and coatings,
road tars, roofing and water-proofing materials, pipeline enamels,
fiber conduit and fiber pipe saturants, carbon electrode binders,
foundry compounds, industrial fuels and wood preserving oils and
chemicals. The refined chemicals from coal tar and light oil were
the starting materials for synthetic organic chemicals of the day,
including dyestuffs, drugs, disinfectants, insecticides, antiseptics,
flavoring components, vitamins, food preservatives, perfumes,
photographic materials, plastics and elastomers. Coke and tars were
used as heating materials in both the domestic (coke only) and
industrial sectors.
The manufactured gas industry in the United States became
prominent during the two world wars. Peak production of coal
tar products in the U.S. occurred in the years prior to World
War II. This era was a period of marked changes in coal tar product
patterns. Petroleum asphalts became favored over road tars
produced from coal and demand decreased dramatically. Creosote
production fell mainly because of the reduced demand for creosoted
crossties by American railroad lines. Light-oil recovery decreased
due to foreign imports and the growing use of petroleum-derived
products. Finally, as natural gas became available by pipeline in
the northeast, it was no longer economically feasible to maintain
aging facilities which produced manufactured gas for domestic use.
MANUFACTURED GAS PROCESSES
The manufactured gas processes changed significantly over the
years that the industry operated. However, the basic process con-
sisted of the following three general operations:
• Distillation—heating coal, coke or oil to drive off or crack
organic carbon-based materials (in the presence of steam, in some
cases)
• Condensation—cooling the manufactured gas to remove the
condensible fraction (tars)
• Purification—washing and/or making contact with iron oxide-
soaked chips and other materials to remove toxic materials from
the gas
In addition to these three processes, enrichment processes were
utilized in some cases. For example, carburetion was one of the
earliest enrichment processes in which a petroleum distillate was
mixed with the hot gases and cracked in a brick chamber. Later
enrichment processes utilized catalysts to modify the chemical
makeup of the gas constituents.
Manufactured gas was generated from many different processes;
however, there are five basic types into which all of these processes
generally fell: blue gas, carbureted water gas, coke oven gas,
catalytically cracked gas and oil gas.
Blue gas (or water gas) was a mixture of carbon monoxide and
hydrogen with a heating value of approximately 300 Btu/ft3. The
blue gas was produced by passing steam over coal or incandescent
coke with a resultant endothermic reaction. A cyclic process of
air blasts was used to control the temperature and thereby minimize
the production of excess nitrogen and carbon monoxide. Figure 1
SITE DISCOVERY & ASSESSMENT 93
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is a flow diagram of a typical blue gas producer.
Carbureted water gas was basically an enriched blue gas. Hot
blue gas was enriched in a carburetor with a petroleum distillate
(e.g., Bunker C) and then passed through a superheater (e.g., a
preheated brick chamber) to crack the distillate. Figure 2 is a flow
diagram of a typical water gas producer. The process was cyclical
to control excessive nitrogen and carbon dioxide contamination
of the gas and reduce the overheating of the carburetor and
superheater.
Coke oven gas was a mixture of hydrogen, methane, carbon
monoxide and illuminants (e.g., ethylene) with a heating value of
approximately 500 Btu/ft3. The gas was produced in steel coke
ovens and normally was cleaned at the steel manufacturing plant
to remove tars, ammonia, light oils, naphthalene and some sulfuric
compounds which were sold as separate by-products. Figure 3 is
a flow diagram of a typical coke oven gas process.
Catalytically cracked gas was a mixture of carbon monoxide and
hydrogen with a heating value of approximately 300-400 Btu/ft1.
This process was similar to carbureted water gas in that a low Btu
was enriched by cracking a petroleum distillate over a nickel oxide
catalyst with regulated amounts of steam.
BLUE GAS PRODUCER
GAS PROCESS FLOW
PCOALOR
AND
DESULFURIZATtON
AIR
3 BLOWER
TO DECANTER
Figure 1
CARBURETED WATER GAS PRODUCER
GAS PROCESS FLOW
VENT
STACK
SUPMHEATE
0-w¥->*. lll^
IUN i i •'• r—n
H I I
1 ' A
DOWN
RUN
STEAM
IRSURCTOA
CARBURETED GAS
TO BOOSTER
AND
DESULFURIZATtON
WASH BOX
TO DECANTER TO DECANTER
Figure 2
Oil gas was basically a cracked petroleum distillate (i.e., rang-
ing from kerosene to Bunker C fuel oil). The oil gas was rich in
methane, ethane, hydrogen and light hydrocarbons with a heating
value of approximately 1,000 Btu/ft3. The thermal cracking of the
COKE OVEN
GAS PROCESS FLOW
COKE OVEN PRIMARY EXHAUSTERS TAR NAPHTHALENE
BATTERY COOLER PRECIPfTATOR SCRUBBER
AMMONIA LIGHT OIL H,S
SCRUBBER SCRUBBER ABSORBER
GASHOLDER
CAS
BOOSTER
Figure 3
petroleum distillate was achieved by spraying it onto hot brickwork
(e.g., a superheater similar to that utilized in the production of
carbureted water gas) or a bed of hot catalyst.
BY-PRODUCT/WASTE GENERATION
By-products and wastes generated by the processes of coal/coke
gasification, gas cooling and gas cleaning are linked below:
Process
Coal/Coke Gasification
Gas Cooling
Gas Cleaning
By-prod acts
Gas
Tar
Clean Gas
Ammonium Sulfale
Wulr*
•\-.h. slag and clinkers
Waslewaier and sludges
Spent iron oxide
Gas cooling resulted in the condensation of organic material that
was removed as tar. Gas cleaning was performed to remove
ammonia and toxic compounds. Ammonia scrubbing occurred
primarily at coke oven gas facilities. Other facilities which pro-
duced carbureted water gas and catalytically cracked gas did not
typically include ammonia scrubbing. The removal of ammonia
occurred by simply passing the gas stream through a sulfuric acid
solution \N ith the resultant formation of ammonium sulfate that
was normally sold for the production of fertilizer.
Subsequent to tar removal, toxic compounds (i.e., hydrogen
sull'ide and cyanide) were removed. The most common process for
the removal of these compounds utilized fixed bed purifier boxes.
The purifier boxes contained wooden chips that were treated with
iron oxide which was used as a scavenger for hydrogen sulfide in
the gases. The iron oxide was regenerated by cycling the purifier
boxes (i.e., blowing air through the beds, thereby releasing sulfur
dioxide into the atmosphere). Over time, the iron oxide/wood chip
beds lost their usefulness because of the formation of extremely
stable ferric/ferrous cyanide complexes on the wood chips.
ENVIRONMENTAL CONCERNS
In the evaluation of manufactured gas plant sites, the areas of
potential concern result primarily from the following past practices:
• Spills and leaks of products/by-products during normal opera-
tion and closure of facilities
• Products/by-products that may not have been utilized or were
left in place during closure (e.g., left in process pipes and tanks)
• Wastes that were deposited on-site or off-site
• Wastewaters that were discharged on-site and off-site
94 SITE DISCOVERY & ASSESSMENT
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The specific environmental concerns relative to these operations
and/or practices include:
• Leaching of metals from ash, slag and clinkers land-filled on-site
• Contamination of soils, groundwater, or surface water by spent
iron oxide which contains high concentrations of sulfur and
significant concentrations of various cyanides. Table 1 sum-
marizes compounds that may be identified in spent oxide waste
• Contamination of soils, groundwater or surface water by tars
and light oils. These wastes typically are a complex mixture of
polynuclear aromatic (PNA) compounds and phenols as shown
in Table 2. Environmental concerns stem from the fact that some
of these compounds are known or suspected carcinogens
Table 1
Typical Analysis of Spent Oxide2
Compound
Free sulfur
Moisture
Ferric monohydrate
Ferrous monohydrate
Basic ferric sulfate
Ferric ammonium ferrocyanide
Ferrocoferric ammonium ferrocyanide
Ferric pyridic ferrocyanide
Organic matter peat fiber
Tar
Silica
Naphthalene
Pyridine sulfate
Ammonium sulfate
Calcium sulfate
Ferrous sulfate
Ammonium thiocyanate
Sulfur otherwise combined
Organic matter soluble in alkalies
(humus)
Combined water and loss (by difference)
Concentration (%)
44.70
18.88
5.26
6.25
1.25
3.80
2.50
1.20
4.68
1.21
1.05
0.72
0.77
2.06
0.12
0.02
1.30
1.33
1.54
2.36
100.0
Table 2
Characteristic Compounds Found In
Manufactured Gas Plant Tars1
Benzene
Toluene
Xylenes
Phenol
Cresols
Xylenols
Pyridine
Naphthalene
Methylnaphthalenes
Dimethylnaphthalenes
Acenaphthene
Carbazole
Fluoranthene
Anthracene
Phenanthrene
Fluoranthene
Pyrene
Chrysene
Benz(a)anthracene
Benzo(k)fluoranthene
Benzo(a)pyrene
Perylene
Benzo(g,h,i)perylene
Benzo(b)chrysene
Dibenz(a,h)anthracene
SITE INVESTIGATIONS
The major steps in conducting site investigations and remedial
studies at town gas plants are as follows:
Site Identification/Preliminary Assessment
Site Ranking
Phased Site Investigations
Identification of Problem (Risk Assessment)
Evaluation and Selection of Remedial Measures
The balance of this paper overviews each of the first three steps
of the preceding paragraphs.
Site Identification/Preliminary Assessment
Identification by a utility of town gas plant sites for which it
is responsible can be prompted by:
• Complaints of visible contamination either at the site or as a
result of a discharge to surface water
• Interaction with other utilities due to current and/or prior owner-
ship of a town gas plant site
• Follow-up Superfund 103CC filings on these sites
• Regulatory inquiries
• Internal concerns relative to the potential existence of these sites
Once identified, a preliminary assessment of the site to gather
site-related information is advisable. This assessment should
identify the potential for on-site by-product deposits, site features
that would indicate potential exposure pathways and available
information on site stratigraphy, geohydrology and community
attitudes that would be used to design the site investigation
program.
Examples of potential sources of information that can be used
for the preliminary assessment are identified in Table 3. The overall
objective of Site Identification/Preliminary Assessment is to
develop a data base from which sites can be evaluated as to the
need for future action. In such cases where a utility may have
responsibilities at multiple sites, site ranking typically is utilized
to prioritize the subsequent evaluations. Our firm has found cases
where no further investigation was deemed necessary based upon
preliminary assessments.
Table 3
Potential Sources of Information
For The Preliminary Assessment
Source
Interviews with
Former Employees
Water Resource
Department
(or equivalent)
Utility Records
State/Local Agencies
US FEMA
US Soil Conservation
Service
USGS
Site Visit
Reference: ERT/Koppers,1
(2)
Information/Remarks
• P,lant practices and operation
• Waste disposal areas
• Plant closure
• Location of wells (domestic and
industrial) in site vicinity
• Well boring logs (site stratigraphy)
• Water quality
• Past plant practices and operations
• Aerial photographs
• Title searches
• Former plant layouts
• Regulatory requirements
• Study objectives
• Results from prior studies
• Location in 100-year flood plain
• Classification of soils in
site vicinity
• Location of wells
• Topographical maps
• Evaluate site conditions
• Evidence of contamination
• Impediments to site investigations
• Adjacent land use
SITE DISCOVERY & ASSESSMENT 95
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Site Ranking
For utilities faced with multiple site evaluations, site prioritization
may be appropriate and desirable to allocate resources in a cost-
effective manner. Advantages include:
• Dedication of utility resources to those sites that are considered
the most important and require additional site investigations
• A sound basis for developing site investigation schedules for
multiple sites
• Prioritization of sites in response to regulatory agency inquiries
WESTON uses a modification of the Edison Electric Institute
Ranking System in its approach to ranking town gas plants2. The
system results in a relative ranking of site importance based on
the following factors:
• Site Characteristics
- Size
- Location
- Current Use
Planned Use
• Waste Characteristics
- Operating Period
Visible Surface Waste Deposits
- Odor Problems
- Water Problems
• Resource Characteristics
- Surface Water Proximity
- Surface Water Use
- Groundwater Proximity
- Groundwater Use
• Process Type
For each subcategory under Site, Waste and Resource
Characteristics, and for the category of Process Type, a site is
ranked on a scale of 1 to 5. A score of 1 indicates little importance,
while a score of 5 indicates high importance. The site score is the
sum of the individual scores and the site with the highest score is
ranked the most important (i.e., recommended for additional site
investigations).
Phased Site Investigations
Site investigations are conducted to achieve the following
objectives:
• Confirm the presence of plant by-products and wastes at a site
due to former town gas plant operations as well as determine
the lateral and vertical extent of the source material
• Determine the direction, rate and concentrations of constituents-
of-concern moving off-site
• Gather adequate site information to assess potential site problems
and, if necessary, develop and select remedial measures
• Determine if any immediate remedial measures should be imple-
mented to mitigate environmental concerns
A phased approach is strongly recommended to cost-effectively
achieve the above-listed objectives. In addition, phasing allows
utilization of information from a previous phase to guide subse-
quent phases of potential activity.
An example of a phased field investigation program for a gas
plant site is summarized below:
Phased Field Investigation Program
Phase 1—Shallow soil and sediment samples are collected on-
site for full priority pollutant analysis. Based on the results, "in-
dicator" parameters are selected for analysis in subsequent phases.
The results of the shallow soil sampling will indicate if the site poses
any immediate threats and whether site access should be restricted.
During sample collection, volatile aromatic and PNA field
screening techniques are applied. Correlations can be identified
between field and laboratory results and used in subsequent investi-
gation phases.
Phase 2—Test pits are subsequently excavated to locate the
source material on-site. Additional soil samples are collected and
analyzed for the "indicator" parameters. During backfilling,
piezometers are placed down to the groundwater table in selected
test pits. These piezometers are surveyed and used to measure
groundwater levels to determine groundwaier direction.
Phase 3—Upgradient, downgradient and on-site wells are
installed based on the groundwater flow direction identified. After
well development, groundwater samples are collected for chemical
analysis. Permeability testing is performed to derive soil permea-
bility data and calculate groundwater flowrates.
Field screening methods are expedient, effective and inexpensive
ways to locate the lateral and vertical extent of contamination. Even
during intense soil sampling efforts at a site, field screening can
be used to increase knowledge of the site. Relevant to town gas
plant sites, our firm has developed and had the U.S. EPA validated
field screening methods for the determination of total polynuclear
aromatics (PNAs) and volatile aromatics in both soils and water.
The PNA screening method, which is being implemented at two
Superfund sites, consists of rapid extraction and analysis using UV
flourescence spectrophotometry. The volatile aromatic screening
technique entails collection of a headspace sample from a field
sample in a closed container. The gaseous sample then is injected
into a portable gas chromatograph (Photovac model 10AIO).
CONCLUSIONS
Gas plant wastes contain a wide range of chemical constituents
that have persisted in the environment. The approach to site
characterization should consist of site identification/preliminary
assessment, site ranking and phased site investigations. Site ranking
can be used to prioritize multiple sites for further investigations.
In some cases, this ranking system has been used as a basis for
selecting the No Action alternative.
The phasing of site investigations results in cost savings through
the use of field screening techniques, "indicator" parameters for
analysis and the collection of on-site data prior to investigating
off-site locations. Finally, WESTON has developed field screening
techniques for volatile aromatics and PNAs, two classes of com-
pounds typically found in town gas plant wastes. Advantages in
using these methods include reductions in laboratory costs, quicker
turnaround times and greater knowledge of site contamination.
REFERENCES
1. ERT/Koppers, Handbook on Manufactured Cos Plant Sites, Edison
Electric Institute, Washington, D.C., 1984.
2. Hill, W.H., Recovery of Ammonia, Cyanogen, Pyridine, andOthff
Nitrogenous Compounds from Industrial Gases," 1945.
3. Wilson, D.C. and Stevens, C, "Problems Arising from the Redevelop-
ment of Gas Works and Similar Sites," Prepared for Department of
the Environment, U.K., 1981, p. 175.
96 SITE DISCOVERY & ASSESSMENT
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Dioxin Contamination at Historical Phenoxy
Herbicide Mixing and Loading Locations
Steven H. Simanonok
U.S. Environmental Protection Agency
San Francisco, California
Pamela Beekley
Radian Corporation
Sacramento, California
ABSTRACT
A field study was performed to determine if 2,3,7,8-TCDD per-
sists in a former phenoxy herbicide use area. A search of histori-
cal records determined the exact kinds and amounts of herbi-
cides used. The study focused on helicopter landing spots (heli-
spots) where the herbicides were mixed and loaded prior to appli-
cation. Product spillage and rinsate disposal from spray opera-
tions likely would have occurred at these locations.
Soil samples were collected at five helispots. Surface drain-
age pathways from the helispots were sampled to assess migra-
tion via paniculate transport. Sediment samples were obtained
from nearby streams. Wildlife from the area were collected to
measure dioxin levels in animal tissue. Background, duplicate
and blank samples were included with the soil samples for qual-
ity assurance purposes. Duplicate samples of animal tissue were
included when sufficient tissue volume existed.
High resolution GC/MS analyses of the soil samples detected
dioxin at three helispots and in some soil samples at short
distances from the mix and load areas. Dioxin was not detected in
the sediment and wildlife samples.
INTRODUCTION
The U.S. EPA initiated the National Dioxin Study to deter-
mine the extent of dioxin contamination in the United States.
The U.S. EPA focused on 2,3,7,8-tetrachlorodibenzo-p-dioxin
(2,3,7,8-TCDD) because it is considered the most toxic of the 75
chlorinated isomers of dioxin. Exceptionally low doses of 2,3,7,8-
TCDD elicit both acute and chronic toxicity in animals. 2,3,7,8-
TCDD is the most potent animal carcinogen evaluated by the
U.S. EPA and is a potential human carcinogen.'
2,3,7,8-TCDD is formed as an inadvertent contaminant in the
manufacture of trichlorophenol. Subsequent derivatives of tri-
chlorophenol include the herbicides 2,4,5-T and Silvex which
were used primarily to control weeds on rice, rangeland, forests
and rights-of-way. All uses of 2,4,5-T and Silvex now are ban-
ned in the United States.
The National Dioxin Study investigated locations where tri-
chlorophenol and its derivatives were manufactured, formu-
lated and used. The U.S. EPA identified 20 trichlorophenol pro-
duction facilities with 79 associated waste disposal sites and 637
potential formulation locations where the herbicides were blended
and packaged for distribution. The U.S. EPA selected a num-
ber of herbicide use areas for sampling. This paper discusses
residual levels of 2,3,7,8-TCDD at one such herbicide use area in
a national forest.
BACKGROUND
From 1965 to 1969, the phenoxy herbicides 2,4-D, 2,4,5-T
and silvex were aerially applied in the Globe Ranger District of
the Tonto National Forest near Globe, Arizona. This herbicide
use project was designed to improve rangeland and to increase
water runoff, resulting in increased water yields for downstream
users.
Complaints regarding spray drift, deformed animals and
human illness were received immediately after the 1969 spray
treatment. The U.S. Forest Service convened two task forces and
an interdepartmental panel of experts to assess the health and
environmental consequences of the herbicide project. Silvex was
detected in some environmental samples collected. 2,3,7,8-TCDD
was detected at 0.5 ppm in one sample of unused herbicide.
However, laboratory methods had not yet been developed to ana-
lyze environmental samples for 2,3,7,8-TCDD in the low ppb or
ppt ranges.2
Several lawsuits were filed after the 1969 spray season.3 The
lawsuits gained national attention and became known as the
Globe Spray cases. Due to the litigation, the U.S. Forest Service
maintained the records relating to all 4 years of herbicide use in
the Globe Ranger District.
HERBICIDE USE AREA 1965-1969
Figure 1
Location of Herbicide Use Area
SITE DISCOVERY & ASSESSMENT 97
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SITE SELECTION
The study area was selected because accurate records existed
from the 1965-1969 spray season. In addition, the herbicides
were used prior to 1970 when levels of 2,3,7,8-TCDD in 2,4,5-T
and Silvex were limited by the Federal government.' A review of
Federal and state regulatory agency files did not indicate any sub-
sequent herbicide applications. Fig. 1 shows the location of the
herbicide use area selected for study.
PREPARATION OF A SAMPLE PLAN
The study was designed to determine if 2,3,7,8-TCDD could
be detected 15 years after herbicide usage. Historical records were
reviewed and a sample plan was prepared that detailed the orig-
inal herbicides used and the soil, sediment, wildlife and field qual-
ity assurance samples necessary to meet the study objective. A
thorough discussion of the elements of a sample plan is presented
elsewhere in these proceedings.'
Field sampling techniques were incorporated into the sample
plan by reference to guidance prepared specifically for the Na-
tional Dioxin Study.' Laboratory analyses and quality assurance
were also specified.'
Herbicide Use
A review of U.S. Forest Service files determined the exact
kinds, amounts and locations of the herbicides used. Table 1 con-
tains a summary of this information.
Soil Samples at Helispot Locations
Sample points were focused on areas most likely to be contam-
inated. These areas were the helicopter landing spots (helispots)
where the herbicides were mixed and loaded prior to applica-
tion. Product spillage and disposal of rinsate from spray opera-
tions likely would have occurred at these locations.
U.S. Forest Service files were reviewed for narrative accountj
and maps dating from the herbicide use project. While the maps
indicated a number of helispot locations, there was uncertainty
whether specific helispots had been used for herbicide mixing and
loading or for routine fire suppression purposes.
Knowledge of herbicide operations clarified the distinction be-
tween fire suppression and herbicide mixing and loading heli-
spots. A fire suppression helispot is a flat, prominent location
where a helicopter could land to deploy or retrieve firefighters.
A helispot used for herbicide operations would have two levels:
an upper level for helicopter landing, and a lower level where the
55-gal drums of herbicide and mixing equipment would be lo-
cated.
Interviews with the original spray crew indicated that three heli-
spots had been used for the entire herbicide use project. Historical
aerial photographs were examined for ground scars which con-
firmed that heavy equipment had prepared the three helispots co-
inciding with the herbicide use period.
Sediment Samples
2,3,7,8-TCDD adheres to soil and is transported along surface
drainage patterns. Creeks and stock tanks downgradient from the
herbicide use area were identified for sediment sample collec-
tion. Topographic maps were examined and field observations
were made for sediment deposition areas. Kellner Creek, Ice-
house Creek, Final Creek and Blue Tank receive drainage from
the herbicide use areas and were selected for sediment sample
collection.
Tiblel
Summery of Herbicides U«ed
Dates
of Application
August 23,24,
25, 1965
May 7,8,
1966
May 31,
June 1,2,3,
1968
June 8,9,10,
11, 1969
Chemical USDA Reg.'8' Application Rate"5' Total Acres Total(b)
Name Manufacturer Number (Ibs per acre) Treated Application
2,4-D,
isooctyl
2,4,5-T,
isooctyl
2,4-D,
Isooctyl
2,4,5-T,
isooctyl
ester
ester
ester
ester
Silvex,
propylene glycol
butyl ether ester
Silvex,
propylene glycol
butyl ether ester
Monsanto 524-115 1 lb
Thompson- 148-431 1 lb_
Hayward
Monsanto 524-115 1 lb~
Thompson- 148-431 1 lb
Hayward
Dow 464-162 2 Ibs
Dow 464-162 2 Ibs
2 Ibs 1,496 3300 Ibs
2 Ibs 1,060 1980 Ibs
1,800 3520 Ibs
1,900 3740 Ibs
2,4-D,
isooctyl
2,4,5-T,
isooctyl
ester
ester
2,4,5-T,
butyl ester
2,4,5-T,
2-ethylhexyl ester
Monsanto
Thompeon-
Hayward
Hercules
Hercules
524-115 1 lb
148-431 1 lb_
891-46 2 Ibs
891-45 2 Ibs
Estimate of 24 gallons
solution remaining in
2 Ibs project spray tanks from
previous project.
30 gallons of undiluted
material leftover from
1966 demonstration. This
material applied at start
of operations.
notes: (a) USDA Pesticide Registration Numbers were converted to EPA Pesticide Registration Numbers in 1971.
(b) All pounds Indicated are pounds acid equivalent for the herbicides used.
98 SITE DISCOVERY & ASSESSMENT
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HERBICIDE USE AREA 1965-1969
GLOBE
Figure 2
Location of Helispots Within the Study Area
Wildlife Samples
State biologists indicated that many wildlife species were avail-
able for sampling including deer, javelina and coyote. Fish from
stock tanks also could be collected. Arrangements were made
with the Arizona Department of Game and Fish for a scientific
collector's permit and assistance in sample collection. Arrange-
ments also were made with a local veterinarian for removal of tar-
get tissues (kidney, liver and fat) from large game animals such as
deer and javelina. Small animals were to be submitted whole for
analysis.
Quality Assurance
Soil and sediment samples were planned to include at least 10%
duplicate samples, laboratory-certified organic-free blank sam-
ples and performance evaluation samples. Background samples
were proposed from the top of Final Mountain, upgradient from
the former herbicide use area. The U.S. Forest Service verified
that herbicides had never been applied in the background sample
collection area.
For quality assurance in the wildlife samples, subsamples of the
large game tissues were to be obtained by the project veterinarian
when sufficient volume existed.
SAMPLE COLLECTION
Soil and Sediment Samples
Each helispot was divided into equal-area grid cells, and a soil
sample was obtained from the center of each cell.
The soil sampling device described in the sample plan was a
4-in. deep tulip bulb planter so that equivalent samples could be
collected throughout the study. However, this sampling device
proved difficult to use in the field, as it could not penetrate the
hard and rocky ground. Garden trowels were substituted for the
tulip bulk planters, and the sampling personnel were instructed to
obtain 4-in. deep samples. Soil samples also were collected at the
bottom of small gullies leading from the helispots where fine par-
ticulate settled.
Sediment samples were collected at each of the locations as
described in the sample plan. All soil and sediment samples were
put in precleaned and prenumbered quart jars, taped shut and
placed on ice for preservation.
Wildlife Samples
Animals were collected in and near the former herbicide use
area. The large game were shot and the freshly killed animals
taken to the local veterinary clinic. The veterinarians completed
necropsy reports and removed kidney, liver and fat tissues. Other
animal tissues were preserved in formalin, to allow for future his-
tological examination if the analytical results from target tissue
indicated the presence of 2,3,7,8-TCDD.
A variety of methods were used to collect the smaller animals.
Table 2 details the wildlife collected. All whole animal and ani-
mal tissue samples were wrapped in aluminum foil and frozen as
soon as possible after collection or preparation. Three animal
tissue subsamples (deer fat, javelina liver and javelina fat) were
SITE DISCOVERY & ASSESSMENT 99
-------
HELISPOT # 1
Figure 3
Sample Points at Helispot #1
submitted in duplicate. Several of the stock tanks had dried up
since the prior reconnaissance trip and no fish were available for
collection.
LABORATORY ANALYSES
All soil, sediment and wildlife tissue samples were shipped to
U.S. EPA laboratories for high resolution GC/MS analyses. To
achieve Quality Assurance and Quality Control objectives, gen-
eral requirements for data comparability, data representative-
ness and data completeness were established under the National
Dioxin Study. Specific data quality objectives for analyses also
were defined (e.g., precision, bias, minimum levels of detection
and isomer specificity). AH data were reviewed and validated.
RESULTS
Soil Samples
2,3,7,8-TCDD was detected at both Helispots K\ and K2 (see
Fig. 4 and 5, respectively). Two analytical, values are reported
at duplicate sample locations. 2,3,7,8-TCDD was detected in
every soil sample collected from the uppermost levels at Heli-
spots #\ and Wi. 2,3,7,8-TCDD also was detected in some soil
sampl.es taken in the small gullies leading away from Helispots
#1 and n.
At Helispot tn> (Fig. 6), 2,3,7,8-TCDD was not detected in any
of the soil samples.
Detection limits for the soil samples were examined. Detec-
tion limits at Helispot #3 ranged from 1.0 to 3.0 ppt. Detection
limits at Helispots #1 and #1 ranged from 1.0 to 9.0 ppt. Since
detection limits were generally lower at Helispot #3, detection
limits could not account for non-detectable levels at this loca-
tion. All values reported for duplicate samples were within accep-
table ranges for the study. One explanation for non-detectable
levels of 2,3,7,8-TCDD at Helispot #3 was that it had not been
used for herbicide mixing and loading.
Sediment Samples
2,3,7,8-TCDD was not detected in the sediment samples from
Kellner Creek, Icehouse Creek, Final Creek and Blue Tank. IV
tection limits ranged from 1.0 to 3.0 ppt for these samples.
Wildlife Samples
2,3,7,8-TCDD was not detected in any of the animal tissue ana-
lyzed. Detection limits ranged from 0.2 to 9.7 ppt. With the ex-
ception of the fat samples from the deer, javelina and coyote,
the detection limits for the other wildlife samples ranged from
0.2 to 1.7 ppt. The fat samples apparently contained other chlor-
inated compounds which interfered with 2,3,7,8-TCDD analysis
and resulted in higher detection limits. One sample of deer kidney
could not be analyzed due to insufficient volume.
Preliminary Conclusions
The soil sample analyses indicated that 2,3,7,8-TCDD did per-
sist at the herbicide mixing and loading locations. Two of the
three helispot samples were contaminated in the ppt range. A
followup study was proposed to determine if contamination had
been adequately characterized within the study location.
FOLLOWUP INVESTIGATION
Subsequent investigation provided more information on the
original herbicide use project. Helispot #1 was the only location
used for all four spray years. Kellner Creek was downhill from
this helispot and provided water for herbicide dilution and rinsing
of spray tanks and equipment. The rinsate reportedly was dis-
posed on the lower level of Helispot H\. The initial sampling may
not have fully characterized this helispot, because the lower level
had not been sampled.
Further investigation was performed to account for the non-
detectable levels at Helispot #3. Records and interviews estab-
lished that Helispot tft had been used for at least 3 of the 4 years
of the herbicide use project. A return visit to Helispot #3 revealed
a nearby location with herbicide use artifacts including 55-gal
drum bung hole covers, a funnel and pieces of hose. These arti-
facts pinpointed the actual mixing location for Helispot #3.
The investigation also identified two other helispots which may
have been used. One location, identified as Helispot #4, was used
in 1969 for an emergency landing on a concrete pad after a spray
hose broke as the helicopter passed between Kellner and lex-
house Canyons.
The other location, identified as Helispot #3, was on a hilltop
adjacent to a residence. While there was no evidence the helispot
had been used for herbicide mixing, the residence was near the
1965-1969 herbicide use area and the study had alarmed the cur-
rent residents.
FOLLOWUP SAMPLE PLAN
Soil Sampling
A sample plan for followup study was prepared. The areas
slated for sample collection were: Helispot 01 (lower level), Heli-
spot #3 (mixing location), Helispot #4 (1969 emergency landing
100 SITE DISCOVERY & ASSESSMENT
-------
Table 2
Summary of Wildlife Collected
Common Name
Scientific Name
Coyote
Canis latrans
Black Rattlesnake
Crotalus spp.
Deer
Odocoileus virginianus
Javelina
Dicotyles tajacu
Glossy Snake
Arizona elegans
Gambel's Quail
Lophortyx qambelli
Garter Snake
Thamnophis radix
Toad
Euro cognatus
Leopard Frogs
Rana pipiens
Sex
Female
Unknown
Male
Female
Male
Male
Unknown
Female
Unknown
Unknown
Unknown
Age
8 months
Unknown
1 year
Fawn
Unknown
Unknown
Unknown
Unknown
Unknown
Unknown
Unknown
Weight
Unknown
Unknown
57 Ibs
23 Ibs
SO Ibs
56 Ibs
Unknown
Unknown
Unknown
Unknown
Unknown
General Location
W of Russell Gulch
N of Spray Area
Icehouse Canyon
Near Helispot #3
W of Road 651
Near Helispot #2
W of Road 651
Near Helispot 12
W of Russel Gulch
S of Rock Tanks
W of Russel Gulch
S of Rock Tanks
Kellner Creek at
Kellner Campground
Kellner Canyon
near Road 112C
Blue Tank
Blue Tank
Blue Tank
Collection
Method
Shot
Shot
Shot
Shot
Shot
Shot
Captured
by Hand
Shot
Captured
by Hand
Netted
Netted
Tissue Sampled
Liver
Whole
Liver
Liver
Liver
Liver
Whole
Whole
Whole
Whole
Whole
, Kidney, Fa
, Kidney, Fa
, Kidney, Fa
, Kidney, Fa
, Kidney, Fa
Composite
VALUES REPORTED = pg/g - Parts Per T/illio
Figure 4
Analytical Results at Helispot 11
VALUES REPORTED = pg/g = Parts Per Trillion
Figure 5
Analytical Results at Helispot #2
SITE DISCOVERY & ASSESSMENT 101
-------
VALUES REPORTED = pg/g Harts 1'ei Trillion
Figure 6
Analytical Results at Helispot #3
HERBICIDE USE AREA 1965-1969
GLOBE
Figure 7
Location of Helispou for Followup Study
spot) and Helispot #5 (adjacent to residence). Fig. 7 shows the
locations of these helispots for followup study.
Fish Sampling
Stock tanks located near Helispot #5 may have been in the heli-
copter's path when the spray hose broke in 1969 and may have re-
ceived spray material. Fish collection was proposed.
SAMPLE COLLECTION
Soil samples were collected in similar fashion to the initial
study. The lower level at Helispot #1 was divided into equal-area
grid cells and a soil sample obtained from the center of each cell
Samples were collected adjacent to the herbicide use artifacts at
Helispot #3 and randomly across this open location. Samples
were collected immediately downgradient of the only two con-
crete pads at Helispot #4 and from the small gullies nearby. This
area currently is used as a public picnic area.
Rather than sample Helispot 13 itself, soil samples were col-
lected in small eroded gullies leading from the belispot through
the residential property. These samples would determine actual
levels on the residential property, and any detectable values could
be used for risk assessment purposes.
Background and duplicate samples were included with each
soil sample set. One composite sample of whole sunfish was col-
lected from a stock tank. Sufficient sample volume did not exist
for a duplicate fish sample.
RESULTS
Soil Sample*
All samples collected from the mixing area at Helispot HI con-
tained 2,3,7,8-TCDD, with levels ranging from 43 to 6623 ppt
The upper value is the highest level of 2,3,7,8-TCDD reported
at any herbicide use area sampled under the National Dioxin
Study. A soil sample collected 25 ft downgradient from the mix-
ing area contained 2,3,7,8-TCDD at 195 ppt.
t
-N-
FOLLOV-
VAI.UK.S KEPONTED
pi:/,«•: - f'.irt-
Figure 8
Analytical Results at Helispot #1 (Lower Level)
2,3,7,8-TCDD was also detected in all samples collected at the
mixing location for Helispot #3. The highest values at this loca-
tion were the duplicate samples collected adjacent to where a run-
nel and pieces of hose were found. These duplicate soil samples
indicates 2,3,7,8-TCDD and 2317 ppt.
102 SITE DISC@VERY & ASSESSMENT
-------
FOLLOW-UP STUDY
-HILLTOP
'2872
2317o
A
1
VALUES REPORTED = pg/g = Parts Per Trillion.
A Location of Herbicide Use Artifacts
Figure 9
Analytical Results at Helispot #3 (Mixing Location)
VALUES REPORTED = pg/g = Parts Per Trillion
Figure 10
Analytical Results at Helispot #4
VALUE? REPORTED -~ pg/g ~- Part* Pel Trillion
Figure 11
Analytical Results at Helispot #5
All soil samples collected at Helispot #4 were non-detectable
with detection limits which ranged from 0.08 to 0.33 ppt. All
soil samples collected at Helispot #5 were non-detectable with de-
tection limits which ranged from 0.08 to 0.26 ppt.
Fish Sample
2,3,7,8-TCDD was not detected in the composite sample of
whole sunfish collected at the stock tank near Helispot #5, at a
detection limit of 0.44 ppt.
CONCLUSIONS
Detectable levels of 2,3,7,8-TCDD may persist at historical
phenoxy herbicide mixing and loading locations where product
spillage and rinsate disposal have occurred. 2,3,7,8-TCDD also
was found at short distances from the mixing and loading areas.
Dioxin was not detected in stream sediment or wildlife samples
collected. Other herbicide mixing and loading locations, such as
those found in agricultural areas and used over longer periods of
time, may contain levels of 2,3,7,8-TCDD in excess of values re-
ported in this study.
ACKNOWLEDGEMENTS
The authors thank Mr. Larry Widner, the Globe District Forest
Ranger, for his patience and cooperation during this project.
Additional thanks are due the Radian Corporation sampling
teams who endured long hours in the field for this study and Ivo
with Computer Sciences Corporation who produced the graphics
for this paper.
REFERENCES
1. U.S. EPA, "The National Dioxin Study," 1986.
2. U.S.D.A. Forest Service, "Interdepartmental Panel Report," 1970.
3. Shoecraft, Sue the Bastards, The Franklin Press, Phoenix, AZ, 1971.
SITE DISCOVERY & ASSESSMENT 103
-------
U.S.D.A. Agricultural Research Service, "Pesticide Registration Waste Sites, 1986.
Notice 70-22." Sept. 1970. 6 Versar. Inc., "Sampling Guidance Manual for the National Dioxin
Shimmin, K.O., Demarest, H.E. and Rubenstein, P.L.. "Field Qual- Study," July 1984.
ity Assurance: A System for Plan Review, Tracking and Activity 7. U.S. EPA, "Quality Asiurance Project Plan for Tieri 3,5,6, and 7 of
Audit," Proc. National Conference on Uncontrolled Hazardous the National Dioxin Study," July 1984.
104 SITE DISCOVERY & ASSESSMENT
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Field Screening Techniques Developed
Under the Superfund Program
J.N. Motwani, P.E.
Stacie A. Popp
Glenn M. Johnson, P.E.
Roy F. Weston, Inc.
West Chester, Pennsylvania
Rae A. Mindock
Roy F. Weston, Inc.
Chicago, Illinois
ABSTRACT
Field screening techniques were developed by WESTON for the
Superfund Program to accommodate the increasing data require-
ments associated with Remedial Investigations/Feasibility Stud-
ies. Techniques have been developed for application at National
Priority List (NPL) sites for field analysis of two classes of con-
taminants: (1) polynuclear aromatic hydrocarbons (PNAs) and
(2) volatile organics.
The methods for screening PNAs and volatile organics were
developed in the laboratory and validated by comparison with
standard laboratory analysis. The method for screening PNAs,
consisting of a one-step field extraction followed by a UV fluores-
cence spectropthotometric analysis, was developed for determina-
tion of total PNAs in soil and water samples.
The volatile organic screening method was developed for detec-
tion of 1,1-dichloroethylene, 1,1,2-trichloroethylene and
1,1,2,2-tetrachloroethylene in a water matrix. This method util-
izes a head space analysis with a Photovac portable gas chroma-
tograph at ambient conditions.
Each of the three screening techniques is a reliable method of
analysis of its respective contaminants and was successfully im-
plemented in the field at different NPL sites. In addition, the field
application of these techniques demonstrated rapid turnaround
times for sample analysis and the cost-effectiveness of field
screening.
INTRODUCTION
The Remedial Investigations/Feasibility studies (RI/FS) pro-
cess for NPL sites under the Superfund Program often have been
prolonged because of data requirements. Many factors, including
issues relating to liability, quality assurance, enforcement and
cost recovery have contributed to significant increases in the
amount of data necessary for completion of a RI/FS. As a result,
the associated schedules and costs to conduct the studies have in-
creased accordingly.
In an effort to expedite the RI/FS process, the U.S. EPA has
encouraged the development of field screening techniques. These
techniques allow a more focused, more complete, expedient and
cost-effective field effort during the RI. The major advantages of
the field screening techniques include:
• Rapid turnaround times enabling cost-saving field decisions
• Analysis of a larger number of samples in the field
• Ability to redirect and focus sampling efforts thereby increas-
ing the accuracy of estimates of zones of contamination and
shortening field schedules
• Optimum selection of samples for off-site laboratory analysis
by standard methods
Fig. 1 demonstrates how screening techniques can be incorpo-
rated into an RI/FS.
This paper summarizes two field screening techniques that were
developed for and implemented at NPL sites during fiscal years
1985 and 1986. These include screening techniques for field analy-
sis of the following classes of contaminants:
• PNAs soil, water and sediment
• Volatile organics in water
This paper presents an overview of the method development
procedures for the field screening techniques. The analytical
methods, equipment requirements, typical costs for implementa-
tion, anticipated sample throughput, examples of typical site
applications and technique limitations are discussed in this paper.
DESCRIPTION OF FIELD SCREENING
TECHNIQUES
PNA Screening Technique
This field technique is a rapid semi-quantitative analytical
method for determining total PNAs in soil, sediment and water
samples (i.e., for contamination assessment at wood treating
sites). The method yields a total concentration of PNAs which is
comparable to the sum of individual PNA compound concentra-
tions obtained from conventional analytical methods (e.g., U.S.
EPA-CLP Protocol).
This screening technique utilizes a UV fluorescence spectropho-
tometer as the detection instrument. The fluorescence spectro-
photometer uses ultraviolet light to excite electrons which will
emit light at certain wavelengths when returning to their initial
state. Different chemical compounds and concentrations of these
compounds in a mixture are determined by the varying degrees
that they absorb a particular wavelength of light (i.e., different
instrument response values). The instrument response is displayed
digitally and on a chart recorder.
The UV spectrophotometer is calibrated using standard solu-
tions with known concentrations of PNAs in acetonitrile or hex-
ane. Measured quantities of each field sample are extracted with
acetonitrile (from soil or sediment) or hexane (from water) sol-
vents in an on-site laboratory. A sample of the extract is then
SCREENING TECHNIQUES & ANALYSIS 105
-------
Field
Investigation
Sampling
Rapid Field
Screening
Selected
Laboratory
Analysis
Data Review
RI/FS Report
Figure 1
Use of Field Screening Techniques in Remedial
Investigations/Feasibility Studies
analyzed using the UV instrument and the PNA concentration is
readily calculated using the measured instrument response and the
calibration curve. The instrument operating conditions are shown
in Table 1.
Volatile Organic Screening Technique
This technique is a quantitative analytical method for determin-
ation of 1,1,2,2-tetrachloroethylene, 1,1,2-trichloroethylene and
1,1-dichloroethylene in water using a portable GC. The results of
the field screening technique correlate well with analytical data
obtained by conventional laboratory analysis.
This screening technique utilizes a portable GC—the Photovac
Model 10A10. The Photovac Model 10A10 uses gas chroma-
tography to separate the components in the gaseous mixture,
followed by detection using UV light. Molecules having ioniza-
tion potentials greater than that of the ultraviolet light source
(11 electron volts) are less likely to be ionized. Once the molecule
is ionized by the UV Energy, the resulting charged particles are
captured in an electric field and detected with a sensitive electro-
meter which amplifies the current for display on a recorder.
Table 1
Method Detection Limit* and Operating Condition!
Retention Method Detection
Screening
Technique
Volatile
Organica
Parameter
1 , 1-Dichloroe thy lane
1,1,2 -Trlchloroethylene
1,1..; , 2-Tetrachloroatnylene
Time
0.62
3.32
l.tl
Ll.lt
(OT/II
1.0
1.0
2.0
Total PHAa-Soll/eolvent
Total PRM- Hater
1-10 ffm (o;/9|
10.0
Caa ChroMtoqraph Column Condition*:
ChroBatoqraph coluvui conditional 1.5* SB-JO aupport and % coatiag
unkAovn. Melluv carrier 9aa at 20 ml/min to eatablivh Method
detection lialta. Bioh grade air at 20 «l/»ln in actual field me.
AHbient temperature.
UV rluoraacence Spectropnotoawter Condition*!
Reaponea - 0
Fixed Scale • 0.1
Recorder Scale - 1000 arv
Slit width: eHCitatlon 10 rm, amiailon 10 em
Wavelength paira
Pair 1
Pair 2
Recorder Speed
Scan Speed
Excitation
210
250
OH..IOD
340
400
10 rmjc
Tim*
NOTE: Both recorder apeed and ac»/i ape«d will be aet automatically
by going into wavelength program.
Dependent upon aite background concentratioa.
The technique entails acquisition of a headspace sample from a
field sample that has been allowed to reach equilibrium. The gas-
eous sample then is injected with inert gas into a Photovac model
10A10 portable gas chromatograph. The associated individual
component concentrations are determined with a simple calcula-
tion, using a previous calibration factor based on standard solu-
tions and the measured instrument response for each sample.
The instrument operating conditions are shown in Table 1.
METHOD DEVELOPMENT PROCEDURES
Before implementation in the field, optimum operating con-
ditions and procedures were determined for each screening tech-
nique. In addition, each method was validated by determining
the recovery fraction from spiked samples and establishing posi-
tive correlations between the screening technique and standard
laboratory analysis.
PNA Screening Method Development
Initially, three target PNA compounds were chosen for both
the soil and water method validation. The compounds chosen
were the most predominant PNAs at the two sites used to test this
technique. These compounds (naphthalene, acenapthene and
phanthrene) also should parallel the behavior of the other PNAs
known to be present on two test sites. Using standard solutions of
the three target compounds, UV fluorescence spectra were gen-
erated over a wide concentration range. The fluorescence data
were used to determine instrument sensitivity and excitation and
emission maxima for the target compounds. This information
then was used to determine optimum sample size, method detec-
tion limits and instrument conditions for both the soil and water
methods. Based on the UV fluorescence characteristics of the tar-
get compounds and knowledge of other PNA compounds known
106 SCREENING TECHNIQUES & ANALYSIS
-------
to be prevalent on the sites, 280/340 and 250/400 were chosen as
the optimum wavelength pairs (excitation/emission) for detection
of total PNAs.
A quantitative fluorescence response was observed for each
target compound from 0.01 to 1.0 ug/1 concentration in the
standard solution. The calibration curve was observed to be
almost linear within one order of magnitude of concentration.
The most accurate quantification was obtained by working within
a concentration range of 0.1 to 1.0 ug/1.
In the final step of the method development for each site,
appropriate extraction solvents were chosen for each method
based on performance (i.e., rapid dispersion in soil), sensitivity
and lack of instrument interference. Acetonitrile was chosen for
the soil/sediment extraction and hexane for the water extrac-
tion. The method for screening soil samples consists of adding
anhydrous sodium sulfate (to absorb water from wet soil) and
UV grade acetonitrile to a weighed amount of soil. The mixture is
shaken vigorously for about 15 sec; after 1 min, it can be filtered.
The extract then is analyzed by the UV fluorescence spectro-
photometer, diluting the extract into a readable range as neces-
sary. For water samples, a measured volume of sample is mixed
with UV grade hexane for about 1 min. After 5 min, the hexane
layer can be removed and analyzed by UV fluorescence.
Background soil and water samples taken from each of the two
sites were spiked with the three target PNAs to establish the
accuracy and precision for both the soil and the water methods.
The methods showed high recoveries of the PNAs as listed in
Table 2. Recoveries above 100% occur because calibration curves
were extrapolated to non-linear response regions, thus giving con-
centrations that were biased on the high end of the scale.
After establishing method performance, soil and water samples
from the site were analyzed by the UV screening method. The re-
sults were compared to those obtained by U.S. EPA CLP GC/
MS techniques. Standard solutions of the seven most prevalent
PNAs previously discussed were used to generate the calibration
curve. The PNA screening technique correlated within an order of
magnitude of the GC/MS results (Table 3).
Volatile Organics Method Development
Initially, five volatile aromatic compounds were selected for
study: 1,1-dichloroethane, 1,1-dichloroethylene (DCE), 1,1,1-tri-
chloroethane, 1,1,2-trichloroethylene (TCE) and 1,1,2,2-tetra-
chloroethylene (PCE). To demonstrate correlation of the data,
laboratory grade water was fortified with a methanolic solution of
the above compounds spanning the concentration range of
0-20jig/I. These solutions were analyzed in triplicate using both
the Photovac and standard laboratory methods (purge and trap—
U.S. EPA method 601). Blanks containing methanol equivalent
to the volume of spike added also were analyzed in triplicate.
Additionally, method detection limits (MDL) for specified com-
pounds were determined from data obtained from the Photovac
Model 10A10. The instrument parameters used during calibra-
tion procedures for the purge and trap system and the Photo-
vac 10A10 are shown in Table 4.
The results showed good response for samples greater than 1 to
2jig/l of the chloroethylenes (i.e., 1,1,2-trichloroethylene). How-
ever, samples of the chloroalkanes (i.e., 1,1,1-trichloroethane)
did not exhibit a measureable response at 1000 jig/1, and the
corresponding alkanes could not be identified. This result can be
expected because of the high ionization potential, which means
these compounds are less likely to be ionized by the Photovac
ultraviolet light. These results are presented in Table 5.
In the second step of the method development, standard cal-
ibration procedures were identified to demonstrate that the
measurement of the standard is not affected by method or matrix
interferences. Calibration standards were prepared at a minimum
of three concentration levels for each parameter by the addition
of secondary dilution standards to reagent water.
Table 2
Method Accuracy and Precision for PNA Screening Technique
for Two Sites
Soil/Sediment Matrix
Total
Concentration
tig/9 or jig/11
6
15
30
150
300
3
15
30
150
300
Water Matrix
9
90
1800
9
90
1800
Average
Recovery (t)
Napthalene/
Acenapthene
B5
63
79
90
92
65.5
79.0
68.6
100.0
93.2
94
98
101
81.0
96.7
94.0
BSD (%)2
2.5
1.8
3.3
0.6
0.0
12.7
6.5
3.3
5.5
2.3
10
4.1
4.5
1.7
1.2
3.9
Average
Recovery (%)
Fhenanthrene
87
77
78
85
89
86.1
92.6
66.4
130.0
94.2
100
97
101
92.6
111.0
96.4
USD <«)2
2.0
1.3
3.0
0.7
0.6
9.6
13.0
7.7
9.6
0.9
11
2.4
3.5
0.8
0.6
3.6
1. pg/1 = Soil matrix concentration; pg/1 = water matrix concentration.
2. RSD = Relative Standard Deviation.
Table 3
Comparison of UV Fluorescence Screening and GC/MS Data for
Total PNA Concentration in Soil, Sediment, and Water Samples from
Two Sites
goil/S*dia\*nt Matrix
SS2
SS3
854
8G-1
. Pit* Concentration. »q/« or tia/l
Typ*
On-*it*
On-lit*
On-lit*
Background
On-lit*
Background
Background
11
1C. 4
21. C
104,000
4.1
230,000
31
4.2
ovrJ
12
C.5
45.5
7«,300
4.2
230,000
4*
1.5
Loor*cc*nc*
13
1.4
CO.I
IS, TOO
3.C
12,000
51
5.4
Avo.
1.1
42.4
•1,300
'4.0
11,000
4C
C.4
OC/M
7.0
120
It, COO
4.1
19,000
33 v
It
On-lit*
On-lit*
(2nd lit*)
On-lit*
Background
Background
4.C
2,COO
3*0,000
14
141
0.7
1,200
-Mg,
1. /ig/1 = Soil matrix concentration; /ig/1 = water matrix concentration.
2. ND = Not Detected.
Table 4
Instrument Parameters for the Volatile Organics Method Development
PURGE AND TRAP
Tekmar liquid Sample Concentrator LSC-2
Tekraar Model ALS Automatic Laboratory Sampler
Hewlett Packard Model 5880A Gas Chromatograph
Tracor Model 700A Hall Elec. Cond. Detector
Carrier: Re 9 40 ml./min.
Analytical Column: 8' x 1/8* SS 1% SP 1000 on Cabopack B
60/80 mesh.
Volumne Purged: 5 ml.
Temperature: 45° for 3 minutes
Program: 8° per minute to 220°
Bold at 220° for 35 minutes
Intergrator: Hewlett Packard Model 3390k
PHOTOVAC 10A10
Carrier: He at 20 ml./min.
Temperature: Ambient approximately (15-24°c)
Injection Volume: 100 ul Teflon
Analytical Column: 1.5' SE-30 Support and % Coating unknown
Integrator: Hewlett Packard Model 3390A
SCREENING TECHNIQUES & ANALYSIS 107
-------
Table 5
Method Accuracy and Precision for Volatile Organic*
Screening Technique
fttndvd .
Concentration Conecntrition CanMntrctlon .,
(WV/U (u /It (Hf/1) MD(%r tecoviryllt
. 1,2-mchloros)thyl*)M
I. 2 hour equilibrium.
2. RSD = Relative Standard Deviation.
Table 6
Performance Audit Samples for Volatile Organlcs
Screening Technique
V»lM
Tro*
Vain*
bitt/11
ept*bL«'
1. Not Present.
2. Unknown VOC is possibly irans-1,2 DCE
Table 7
Estimated Cost Breakdown for Field Implementation'
PNA Screening
Coat
Analytical facilities
(UV fluorescence spectre-photometer,
recorder, analytical balance,
refrigerator, lab trailer etc.)
Disposable equipment
Manpower (2 operators)
Throughput
Estimated average cost per sample
Volatile Organic* Screening
Analytical facilities
(photovac, recorder, lab trailer,
etc).
Disposable equipment
Manpower
Throughput
Estimated average cost per sample
$800 $900/week
$7-8/sample
$600-$700/day
20-30 samples/day
$40-50.
$600-$700/day
$2-3/sanple
$400-$500/day
20 samples/day
525-35.
1. Btsed on 1985 dollars and actual Held experience
The field laboratory met the minimum requirements of the
U.S. EPA Quality Control Office which included an initial
demonstration of laboratory capability and an on-going analysis
of spiked samples to evaluate and document data quality. The
field laboratory demonstrated through the analyses of quality
control check standards that the operation of the measurement
system was under control.
To establish the ability to generate acceptable accuracy and
precision, two performance evaluation samples were provided by
the U.S. EPA. These samples were tested in accordance with the
field screening procedure developed for volatile organics during
the first week of field screening. A review of the data by the
Region V Quality Assurance Office concurred that quantifica-
tion of trichloroethylene and tetrachloroethylene was acceptable
using the volatile organics screening technique. These data are
shown in Table 6.
EQUIPMENT REQUIREMENTS AND
TYPICAL COSTS FOR IMPLEMENTATION
The cost to implement the PNA screening technique in the field
involves equipment, temporary laboratory facilities and operator
salaries. The equipment requirements include a UV fluorescence
spectrophotometer/chart recorder, analytical balance, disposable
laboratory supplies for the extraction process and a small refrig-
erator to preserve standards.
The average expected cost per sample is $40-550 per sample
with a sample throughput of about 20-30 samples per day. The
estimated costs are shown in Table 7.
Volatile organics screening in the field involves equipment,
temporary laboratory and operator salaries. The equipment re-
quirements include a Photovac instrument with a chart recorder
and appropriated disposable laboratory supplies. The estimated
cost is $20-530 per sample with a sample throughput of about
20 samples/day. The estimated costs are shown in Table 7.
The PNA and volatile organics screening techniques can con-
tribute valuable information to field programs. However, there
are limitations associated with the screening techniques. Because
both techniques are actually laboratory procedures modified for
use in the field, the limitations for the procedures are similar and
can be associated with almost any laboratory procedure.
Both the UV fluorescence spectrophotometer and the gas
chromatograph operate at ambient temperature and should be set
up in an area in the field where temperatures are expected to re-
main fairly constant. Therefore, the laboratory trailer should be
equipped with an air conditioning and/or a heating unit.
The PNA screening technique is relatively simple; a trained
technician can perform the analyses. The operator must have
some experience in laboratory extraction procedures, instrument
operation and basic instrument properties and screening theory so
that any problems encountered during field implementation can
be evaluated and corrected.
In addition, an analytical trailer equipped with a fume hood is
required for the PNA screening technique because solvents are
used in the extraction process. Since the PNA screening tech-
nique requires a selection of target compounds and understand-
ing of matrix interferences, it must be validated for each site spe-
cific situation.
The volatile organics screening technique requires a qualified
chemist with previous GC experience. An additional limitation
encountered using the Photovac screening is the requirement of
gaseous samples; therefore, headspace samples of a water matrix
need to be prepared for analysis. The volatile organics screen-
ing has not been developed to screen soil samples.
CONCLUSION
The PNA screening method provides an order-of-magnitude
estimate of total PNA concentration in soils, water and sedi-
ments. This determination allows the sampling effort to concen-
trate on and fully characterize contaminated areas and then focus
off-site laboratory analyses on the most critical areas. The screen-
ing method is site-specific and should not be applied to other
site investigations without laboratory investigation to provide re-
calibration and method validation.
The volatile organic screening technique can be used to de-
termine concentrations of DCE, TCE and PCE compounds in
water using head space analysis. In the past, both methods have
been successfully implemented for on-site analysis. The volatile
organics screening technique was used to analyze groundwater
108
SCREENING TECHNIQUES & ANALYSIS
-------
samples to evaluate the vertical stratification of contaminants in make field decisions such as monitor well and test pit placement,
municipal wells at an NPL site. The PNA screening technique and sample selection for off-site laboratory analysis.
was used to identify zones of contamination at an inactive wood Overall, these field screening techniques have been reliable,
treating site and will be implemented at an active wood treating fast and cost-effective when used within their limitations and in
site in the near future. Soil, sediment and water samples were concert with proper laboratory techniques and quality assurance/
analyzed during an on-site investigation; the data were used to quality control procedures.
SCREENING TECHNIQUES & ANALYSIS 109
-------
Statistical Modeling of Geophysical Data
Charles T. Kufs, P.G.
Donald J. Messinger
Roy F- Weston, Inc.
West Chester, Pennsylvania
Stephany Del Re
U.S. Environmental Protection Agency
Philadelphia, Pennsylvania
ABSTRACT
Complex surface geophysical data sometimes cannot be eval-
uated completely using traditional graphical interpretation tech-
niques. In these cases, statistical models can be useful for restruc-
turing the data set to identify trends not obvious in the raw data.
This approach was used to interpret magnetometry, metal detec-
tion and electromagnetic conductivity data from the Kane and
Lombard site in Baltimore, Maryland.
INTRODUCTION
Surface geophysical surveys are used frequently at hazardous
waste sites to identify the locations of buried wastes, leachate
plumes and subsurface geologic features. In many cases, evaluat-
ing geophysical data is straightforward using traditional graphical
interpretation techniques. Occasionally, however, the data are
too complex to interpret visually, particularly when complimen-
tary geophysical techniques are utilized. Statistical techniques
often can be used in these situations to filter and restructure the
data set to provide an evaluation of what might otherwise appear
to be unrelatable data. The objective of this paper is to describe
a case in which statistical models were used to evaluate complex
geophysical data from a hazardous waste site.
SITE DESCRIPTION AND HISTORY
The Kane and Lombard site is an 8.3 acre parcel of undevel-
oped land located in the southeast quarter of Baltimore, Mary-
land, southwest of the intersection of Kane and Lombard Streets.
It is directly adjacent to Lombard Street on the north, Patterson
High School on the east and south boundaries and is within one-
quarter mile of Baltimore City Hospital and numerous residential
properties.
Between 1922 and 1938, the site was graded and flattened,
probably in conjunction with the construction of the hospital.
Differences in topography between 1922 and 1968 indicate that
approximately 10 ft of fill was distributed on the site after 1922.
Between 1938 and 1966, two major areas adjacent to the Kane
and Lombard site were excavated and may have been used for
hazardous waste disposal, given that drums have been observed in
the fill.
The period between 1966 and 1971 involved further excava-
tions and the construction of Lombard Street and 1-95. This
period is especially significant because it included the excavation
and refilling of roughly two-thirds of the Kane and Lombard site.
If wastes were buried at the site, the burial probably occurred
between 1969 and 1971, possibly in conjunction with the con-
struction of East Lombard Street.1 From 1971 to 1984, the Kane
and Lombard site was used for the unauthorized disposal of con-
struction debris, household refuse and hazardous wastes.
In November 1980, inspectors from the Maryland Department
of Health and Mental Hygiene discovered drums at the property.
The majority of the drums were rusted through or punctured. Air
monitoring near the center of the site recorded organic vapors
between 10 and 250 ppm on an HNu. At the request of the state,
the U.S. EPA conducted an immediate removal of 1,163 exposed
drums in April 1984.
SITE GEOLOGY
The site is located on gently-dripping unconsolidated coastal
plain deposits of the Potomac Group. The most prevalent of
these deposits at the site is the Arundel Formation. The Arundel
clay facies is a poorly bedded to massive kaolinitic and illitic day
with local lenses and pods of quartz sand and silt.2-' The clay is
typically gray, brown, black or red with occasional color mottling
and is up to 30 ft thick. The Arundel sand fades typically is found
within the Anindel clay and is characterized by deposits of wefl-
sorted, medium-to-fme quartz sand interspersed with clay-silt
laminae and very thin clay beds. The Arundel sand facies can be
up to 10 ft thick. Borings drilled at the site in 1971 and 1982 sug-
gest that the upper 20 ft of material consists primarily of fill and
generally stiff, brown, red-brown and black silty-to-sandy day.
Highly variable sand deposits found between 17 and 27 ft bdow
grade in the northeastern portion of the site probably are derived
from the Arundel Formation. Across the rest of the site and be-
low 27 ft deep in the northeastern portion, the deposits appear to
be primarily gray to reddish-brown clay of the Arundel Forma-
tion.
GEOPHYSICAL SURVEY
The geophysical survey of the Kane & Lombard site was con-
ducted in October 1985. The objective of the survey was to gather
information on the nature of the materials on the site and iden-
tify areas where wastes may be buried. The survey consisted of
establishing a 100-ft by 50-ft grid on the site and using electro-
magnetic terrain conductivity (EM), metal detection (MD).
magnetometry (Mag) and ground penetrating radar (OPR) to
scan the grid. The results of the GPR survey are not included in
this presentation, but are summarized elsewhere.'
To compensate for diurnal and other variations and to assist
in equipment calibration, two base stations were established and
monitored. The primary base station was located in the wooded
area on the southeast border of the site. Measurements of EM,
MD and Mag were taken at the primary base station at the be-
ginning and end of each survey day and approximately every 2 to
during the surveys. The secondary base station was located in tht
baseball field east of the site between the site and Kane Street.
Measurements were taken at the secondary base station appro*-
110 SCREENING TECHNIQUES & ANALYSIS
-------
imately every 4 hr.
Electromagnetic Conductivity Survey
The EM survey was conducted along the 50-ft by 100-ft grid
using a Geonics EM 34-3 terrain conductivity meter. In general,
EM measures the electrical conductivity of materials in microm-
hos over a range of depths determined by the spacing and orien-
tation of the transmitter and receiver coils, and the nature of the
earth materials.
Four different EM measurements were made at each grid node
by using coil spacings of 10 (33 ft) and 20 m (65 ft) and holding
the coils parallel to the ground (vertical dipoles) or perpendicu-
lar to the ground (horizontal dipoles). Vertical dipole conductiv-
ity measurements emphasize deeper earth materials relative to
horizontal dipole measurements which emphasize near-surface
materials. The relative depth of response also is directly related
to the distance between the coils. Thus, typical exploration depths
for 10- and 20-m coil separations would be 25 and 50 ft for hori-
zontal dipoles and 50 and 100 ft for vertical dipoles. However,
while both horizontal and vertical dipoles can be used to measure
conductivity over the same depth by using different coil spac-
ings, the relative response at different depths is quite different.
Magnetometry Survey
The magnetometry survey was conducted using a Scintrix MF
2-100 portable fluxgate magnetometer. In general, magneto-
meters measure the intensity of the earth's magnetic field and
local magnetic anomalies. By filtering out the earth's magnetic
field and nulling the instrument to zero, the local magnetic anom-
alies caused by concentrations of metallic objects can be quan-
tified. Under ideal conditions, deposits of ferrous metal, such as
drums and scrap iron, can be detected up to 60 ft deep using
magnetometry.
Metal Detection Survey
The metal detection survey was conducted using a Garrett
ADS-6 metal detector with Bloodhound™ attachment. Metal
detection measurements were recorded as either "0" (no re-
sponse), "1" (weak response) or "2" (strong response). In gen-
eral, metal detectors will respond to deposits of both ferrous and
nonferrous metals up to 10 to 20 ft deep.
DATA EVALUATION METHODS
The data from the geophysical survey were evaluated in both
raw and statistically filtered forms. The first step in the analysis
was to enter the data onto our mainframe computer system and
verify the entries. The four types of EM measurements, the Mag
readings and the MD data were then each plotted and contoured
using the CPS-1 software package. The resulting maps were eval-
uated individually and together, however, they did not reveal any
easily discernible trends or unambiguous anomalies. Trends and
anomalies that were detected by one geophysical technique were
not confirmed by the complementary techniques.
Factor Analysis
To enhance the interpretation of the trends and anomalies
observed, the data from the EM, Mag and MD surveys were
statistically filtered using a procedure known as "factor analy-
sis." In factor analysis, variables such as the EM, Mag and MD
measurements) are combined statistically to produce a smaller
number of new variables called "factors" that account for nearly
the same proportion of variance. Scores for the factors then are
calculated and analyzed in the same manner as the original vari-
ables. These scores will have a mean of zero and a standard devi-
ation of one, thus standardizing the units of measurement and
simplifying subsequent computer calculations.'
The factor analysis of the EM, Mag and MD data was calcu-
lated using the principal components option in the FACTOR
procedure of the SAS '82, Version 4 computer software pack-
age. Four factors were identified in the analysis, representing deep
EM (a composite of the vertical dipole measurements), shallow
EM (a composite of the horizontal dipole measurements), metal
detection and magnetometry.
The estimated response of the EM factors with depth is shown
in Fig. 1. Fig. 2 to 5 are isometric diagrams of scores on the Deep
EM factor, the Shallow EM factor, the metal detection factor
and the magnetometry factor, respectively. These diagrams are
essentially smoothed versions of the diagrams obtained using the
raw data.
10 20 30 40 50 60 70
Depth In F««l
Figure 1
Relative Response of Electromagnetic Conductivity Factors
with Depth
Figure 2
Isometric Diagram of Scores on the Deep EM Factor
(Factor 1)
SCREENING TECHNIQUES & ANALYSIS 111
-------
Figure 3
Isometric Diagram of Scores on the Shallow EM Factor
(Factor 2)
Figure 4
Isometric Diagram of Scores on the Metal Detection Factor
(Factor 3)
Cluster Analysis
To assist in identifying trends and anomalies, the factor scores
were processed using a statistical procedure known as cluster
analysis. In cluster analysis, measurements (such as the factor
analysis scores) are grouped according to statistical measures of
their interrelatedness.' The cluster analysis of the factor scores
was computed using the Ward's-Method option in the CLUSTER
procedure of the SAS package. The cluster analysis identified
four areas of the site that appear to represent:
• "Background Areas (Cluster I)"—include geophysical grid
nodes primarily in the western and southern portion of the
site.
• "Debris" Areas (Cluster 2)—include geophysical grid nodes
primarily in the southeast-northwest trending band across the
central portion of the site.
• "Waste" Areas (Cluster 3)—include geophysical grid nodes
primarily in the northern portion of the site.
• "Anomalous" Area (Cluster 4)—includes only one small area
in the northeastern portion of the site.
The locations of these clusters are shown in Fig. 6.
Figure 5
Isometric Diagram of Scores on the Magnetometry Factor
(Factor 4)
Figure 6
Location of Test Pits Relative to Cluster Analysis Groups
Discriminant Analysis
To interpret the basis for the groupings formed from the cluster
analysis, the clusters were evaluated using a procedure known as
discriminant analysis. Discriminant analysis is a linear regression
technique in which data groupings (e.g., the clustered geophysi-
cal grid nodes) are related to a function of a set of independent
variables (e.g., the four factors that were derived from the six
original geophysical measurements). The functions then are
assessed to help interpret the underlying nature of the data dus-
ters. The discriminant analysis of the grid node clusters with the
geophysical factors was computed using the D1SCRIM and
CANDISC procedures of the SAS package. The DISCRIM pro-
cedure was used to reassess the clusters to identify any misdassi-
fied grid nodes. The CANDISC procedure was used to calculate
the three discriminant functions which are:
DF-1 = 10.97 (Deep EM Factor) - 0.44 (Shallow EM Factor) + 0.02
(Metal Detection Factor) - 0.15 (Magnetometry Factor)
DF-2 - 0.62 (Deep EM Factor) - 1.20 (Shallow EM Factor) + O.<0
(Metal Detection Factor) + 1.34 (Magnetometry Factor)
DF-3 =0.11 (Deep EM Factor) + 0.95 (Shallow EM Factor) + 0.98
(Metal Detection Factor) + 0.31 (Magnetometry Factor)
The first discriminant function (i.e., DF-1) was interpreted to
112 SCREENING TECHNIQUES & ANALYSIS
-------
represent deep (i.e., over 20 ft) stratigraphic or groundwater
quality anomalies. This function segregated cluster 4 from the
other clusters. The second and third discriminant functions were
interpreted to represent aspects of waste disposal. The two func-
tions segregated all four clusters when plotted against each other
as shown in Fig. 7.
-2.0 -1.5 -1.0 -O.I 0.0 0.1 1.0 1.5 2.0
Figure 7
Bivariate Plot of Discriminant Functions 2 and 3
Figure 8
Contour Plot of Discriminant Function 3
Figure 9
Contour Plot of Discriminant Function 2
Figure 10
Contour Plot of Discriminant Function 1
Discriminant function 3 appears to differentiate parts of the
site that have been excavated and filled from those that are
natural, as shown in Fig. 8. The trend of the zero contour in
Fig. 8 corresponds well with the limits of site excavation as shown
in a 1969 aerial photograph.' Discriminate function 2 appears to
differentiate between metallic debris (i.e., high positive values
for DF-3) and high conductivity debris such as concrete (i.e.,
high negative values for DF-3), as shown in Fig. 9. The trends in
this figure appear to correspond to the materials found in the test
pits, as discussed in the next section. Discriminant function 1 ap-
pears to follow the general trend of suspected contaminant move-
ment at the site, as shown in Fig. 10.
TEST PIT EXCAVATIONS
To verify the findings of the geophysical survey, 24 test pits
were excavated to a depth of approximately 10 ft at the loca-
tions shown in Fig. 6. Table 1 summarizes the results of the test
pit explorations relative to the statistical analysis.
Based on these results, it appears that areas in Cluster 2 have
been excavated and filled with wastes consisting primarily of
SCREENING TECHNIQUES & ANALYSIS 113
-------
mixtures of household trash and construction debris (e.g., scrap
metal, wood, concrete and brick). Areas in Cluster 3 include the
same type of waste as is found in Cluster 2 areas as well as decom-
posed tanks and drums that may have contained volatile wastes.
The majority of test pits excavated in Cluster 1 areas found no
evidence of buried wastes, thus supporting the contention that
these are undisturbed areas.
Table 1
Results of Test Pit Explorations
Clutter Identification
Clutter Description
1234
•Biigrounfl" "Debrla1 Ikete* -Anaealau'
ATM Aree Aree AnaMly
Keen Value of Diacrlalnant runctloni
1 - Deep Conductivity Varlete -1.34
2 - Mitel («)/3ncreU(-) varlate 0.52
J- Buried Matte Varlete -1.11
Hater of Ifcet Plte in Clueter Aree 4
net Pit Identification AX,
3.X
Percentage of Tcet Pit Containing i
Little or W> Debrla 75
nnfce and Drum 0
Strap Nttal 0
Concrete, Brick 25
Nxd, Paper 0
Maccllaneoua Treeb 25
Organic vapore (BHi) 0
BMoe of Hudlnge (ppa) —
Htthane (Gaitecb) 0
Mnge of Reading, (pp.) -
O
-------
Portable X-Ray Fluorescence as a Screening Tool for
Analysis of Heavy Metals in Soils and Mine Wastes
Richard W. Chappell
Andrew O. Davis, Ph.D.
Roger L. Olsen, Ph.D.
Camp Dresser & McKee Inc.
Denver, Colorado
ABSTRACT
X-ray fluorescence (XRF) has several advantages over atomic
absorption and inductively coupled plasma techniques that make
it useful for the screening analyses of environmental samples.
These advantages are: rapid turnaround time, multi-element
analytical capacity, nondestructive analyses, minimal quantity of
sample required and cost-effectiveness. Further, a portable XRF
instrument has the capability of providing on-site analyses that
can be incorporated immediately into the field investigation pro-
gram. The realization of the potential of a portable XRF device
has led to an increase in its use in remedial investigations at hazar-
dous waste sites. In most cases, however, the accuracy and preci-
sion of the analyses, along with the method detection limits, have
not been well characterized. In this paper, these parameters are
established for a variety of soil/tailings matrices, calibration tech-
niques and field situations.
The authors have used a portable XRF analyzer to determine
heavy metals concentrations in soils, sediments and mining wastes
at three hazardous waste sites in Colorado and Montana. The
elements determined using a Columbia Scientific portable XRF
analyzer were lead, arsenic, copper, zinc and iron. These three
sites represent several potential applications of XRF analyses, in-
cluding: (1) on-site selection of sample locations necessary for
definition of contaminant boundaries, (2) screening of samples
for further analyses through the Contract Laboratory Program
(CLP) and (3) statistical and geochemical evaluation of the spatial
variation of metals concentrations. The requirements and limita-
tions of XRF analyses for each application are evaluated.
The results obtained substantiate the dependence of method
detection limits on sample matrix variability and analyte concen-
tration ranges. The accuracy and precision of the analytical tech-
nique also depend on the number and type of calibration stan-
dards used. These conclusions are demonstrated by statistical
evaluation of the results of the calibration for combinations of 5,
10,15 and 20 standards. The results of both replicate analyses and
XRF versus CLP comparisons are presented and are used to
determine potential sources of error and their relative magnitudes
for the entire procedure. This knowledge can be directly applied
to the design of field programs that more effectively meet the ac-
curacy, precision and detection limit requirements of XRF
analyses for remedial investigations at hazardous waste sites.
INTRODUCTION
As part of the remedial investigations at three hazardous waste
mining sites, screening for heavy metals contamination was per-
formed with the aid of a portable energy dispersive X-ray fluor-
escence (XRF) analyzer. At Site A in Colorado, definition of a
1,000 mg/kg Pb isopleth using on-site XRF in conjunction with
geostatistics was accomplished.1 In the identification of hotspots
and areas requiring further investigation at Site B in Montana,
XRF provided a useful and cost-effective method for screening
for As, Pb, Cu and Zn. XRF screening also was utilized to select
samples for further analysis through the Contract Laboratory
Program (CLP). At Site C in Colorado, analyses for Pb, As, Cu,
Zn and Fe in split spoon tailings samples provided additional in-
formation on the relationships between degree and depth of con-
tamination. In this way, zones of metal accumulation and leached
zones of metal depletion could be identified.
The potential use of XRF spectrometry as a screening technique
for trace constituents at hazardous waste sites has been
demonstrated by several studies.2'3 In these cases, however,
analyses were performed by dedicated laboratory instruments
employing sophisticated computer software. The additional ad-
vantage of immediate results has led to an increased interest in
portable XRF systems, which necessarily are less sophisticated.
The purpose of this study was to outline the techniques essential
to the proper use of portable XRF instruments and to evaluate the
results obtained in relation to the designed screening use of the
method.
XRF THEORY
The fundamental principle of X-ray fluorescence (XRF) or
emission spectrometry is the detection and measurement of the
X-rays emitted from excited atoms in a sample. The excited state
is achieved when the critical binding energy of an electron in a
particular shell is exceeded by the energy of the incoming source
particle. When this happens, an orbital electron is removed from
the shell (the atom is ionized) and another electron from a higher
energy shell takes its place. The excess energy released as an X-ray
photon during this process is characteristic of the atom from
which it was produced. There are, of course, many complications
to this simplified discussion of XRF theory, and a vast amount of
literature addresses them in detail.4-7
Two general types of emission spectrometers can be used:
wavelength dispersive (WD) and energy dispersive (ED). Wave-
length dispersive systems normally provide very high resolution
(sharp narrow peaks) but, because of the additional diffraction
step, they suffer from low efficiency (the energies of the charac-
teristic X-rays are attenuated by the diffraction process). Energy
dispersive systems, on the other hand, are highly efficient but
have less resolving power. Because ED spectrometers do not re-
quire high source energies for excitation (i.e., they are more ef-
ficient) and elaborate mechanisms for geometric positioning of
the detector, they are more adaptable for use in the field. Several
compact ED systems are now available, some with sophisticated
software capabilities.
SCREENING TECHNIQUES & ANALYSIS 115
-------
The energy dispersive XRF system used in this study was a Col-
umbia Scientific X-MET 840 portable analyzer. The X-MET 840
employs a radioisotope source for sample excitation and a high
resolution proportional counter for X-ray detection. For the
elements analyzed for in this study (Pb, As, Cu, Zn and Fe), a 100
millicurie source, composed of Cm 244 which emits Pu L X-rays
with energy ranging from 12 to 20 KeV, was used. The resolution
of the spectrometer, as defined by the full width at half the max-
imum (fwhm) height of the Mn K alpha peak at 5.9 KeV, is about
0.83 KeV or 14%. Typical laboratory ED instruments are now
capable of resolutions of less than 0.15 KeV or 2.5Vo.
SAMPLE MATRIX EFFECTS
The most important consideration in the measurement of X-ray
energy is the influence of sample matrix effects. Matrix effects
can either increase or decrease characteristic X-ray intensities and,
if not corrected for, can lead to significant accuracy problems. In
general, these effects can be divided into either physical or
chemical matrix effects.
Physical matrix effects are the result of variations in the
physical character of a sample. They may include such parameters
as particle size, uniformity, homogeneity and surface condition.
For example, consider a sample in which the analyte exists as very
fine particles within a matrix composed of much coarser material.
If two separate specimens (aliquots) of the sample are ground in
such a way that the matrix particles in one are much larger than in
the other, then the relative volumes occupied by the analyte-
containing particles will be different in each. When measured, a
larger amount of the analyte will be exposed to the source X-rays
in the specimen containing larger matrix particles, resulting in a
higher intensity reading for that specimen.
Chemical matrix effects result from differences in concentra-
tions of interfering elements. These effects appear as either spec-
tral interferences (peak overlaps) or as absorption/enhancement
phenomena. Both effects are common in soils contaminated with
heavy metals. For example, Fe tends to absorb Cu K X-rays,
reducing the intensity measured by the detector. This effect can be
corrected if the relationship between Fe absorption and X-ray in-
tensity can be modeled mathematically. Obviously, establishment
of all matrix relationships during the time of instrument calibra-
tion is critical.
Sample matrix effects can never be fully eliminated. They can
become relatively insignificant, however, through proper sample
preparation and calibration techniques. The techniques used in
this study are addressed more fully in the following section.
METHODOLOGY
Sample Preparation
Samples to be analyzed by XRF (including calibration samples)
were placed in aluminum pans, air-dried and mixed as well as
possible. A representative portion of each sample (40-100 g) was
ground to less than 100 mesh, and a 5-10 g aliquot of the resulting
powder was then analyzed with the spectrometer. Sample
preparation time averaged between 10 and 15 min/sample. Actual
analysis time was 4 min/sample.
By saturating the sample preparation step, analytical variations
due to physical matrix effects were minimized. In other words,
although the physical characteristics of the samples may have
been affecting the intensities of X-rays, correction for these ef-
fects was not necessary because they were the same for all
samples. Of course this assumption was valid only for samples
with identical or at least very similar matrices (e.g., for samples
collected from the same site). Although the assumption was
reasonable from a theoretical standpoint, in practice it was dif-
ficult to test. However, one important aspect, homogeneity of the
ground powder, was tested. The results of this determination are
evaluated later in this paper.
Calibration
The calibration of the XRF spectrometer was based on
previously collected and analyzed samples from each site. The*
samples were handled with the same procedures outlined above in
"Sample Preparation." After digestion with HNOj/H^ ac-
cording to the procedures specified by the CLP, samples were
analyzed by either inductively coupled plasma (ICP) or atomic
absorption (AA) techniques by different laboratories with CLP
procedures. The samples do not represent "true" calibration
standards in the sense that the accuracy of the different CLP
laboratories was not beyond repute. Nevertheless, the potential
calibration error due to the inaccurately known concentrations in
the samples was probably much less than the potential matrix ef-
fect errors that would result using "true" standards with
unknown matrices.
Calibration was accomplished by first measuring the intensities
of the characteristic analyte X-rays, then developing a concentra-
tion versus net intensity regression curve. The calibrations
employed for each element and for each site were essentially
mathematical models designed to compensate for sample matrix
effects specific to the site. The goal was to optimize the calibra-
tion for each analyte by correcting for both spectral overlap
and/or element interference, if necessary. Spectral overlap, which
occurs when two peaks are not completely resolved, was removed
by deconvolution (subtraction of one peak intensity from that of
another). Absorption or enhancement of characteristic X-rayj
due to the presence of interfering elements was handled by multi-
ple linear regression analysis. All of the software necessary for
calibration is contained within the instrument.
Table 1 summarizes the results of the calibration obtained for
each element at each site. The table provides the number of
calibration standards (n), the range of concentrations in the stan-
dards, the instrument detection limit (discussed in next section)
and the resulting correlation coefficient. In all cases, the calibra-
tion was excellent with correlation coefficients typically greater
than 0.9S.
Tibtel
XRF Calibration Piranclcn
Sit*
III* A
Sit* 1
Sltt C2
tleMnl
Fb
fb
As
Cu
Zn
rb
Aa
Cu
Za
r«
'
i
20
16
It
20
20
20
20
20
20
Analytical
tanf*
<•*•'««>
0-1,000
0-1,200
0-1,700
0-2,200
0-2,500
0-4,800
0-230
0-3,900
0-3.400
0-180,000
1
SO1
(•f'kt)
38
97
91
190
267
423
20
137
97
18,200
Correlation
CotHlcltM
(*>
0.999
0.949
0.963
0.963
0.943
0.933
0.963
0.991
0.997
0.931
i
rar
(•!/*»)
120
73
90
60
30
43
13
90
60
140
I Overall iiandtid deviation (root mean iquire of UK residuals) for UK re«re>BOn
2 Model li (20 calibration lampta)
3 Inilnunenl detection limit
ANALYTICAL PRECISION
Replicate analyses were performed to determine the analytical
precision of the X-MET 840. For each site, a check sample was
analyzed at regular intervals throughout the analytical run. The
results, shown in Table 2, include both instrumental error and er-
ror due to spectrometer drift. The data indicate that replicate
116 SCREENING TECHNIQUES & ANALYSIS
-------
precision (as indicated by CV, coefficient of variance or standard
deviation divided by the mean) is generally less than ± 20°7o for
concentrations approaching the method detection limit. At higher
concentrations, however, precision is generally less than ±5%.
Table 2
XRF Replicate Precision
Site
Element
Hean
SD
CV (X)
Site A
Site B
Site C2
Pb
Pb
As
Cu
Zn
Pb
As
Cu
Zn
Fe
93
16
16
16
16
35
35
35
35
35
409
143
215
846
550
713
51
597
728
13,800
52
32
33
21
17
14
7
27
20
870
12.7
22.4
15.3
2.5
3.1
2.8
12.9
4.5
2.8
6.3
156
96
99
63
51
42
21
81
60
2,610
1 Method detection limit
2 Model #5 (20 calibration samples)
XRF DETECTION LIMITS
The limiting factor for XRF precision is the error associated
with the X-ray counting process. This error results from the ran-
dom nature in which X-rays are emitted from the radioisotope
source, excited in the sample and counted by the detector. Thus,
the lower limit of detection can be estimated from the standard
deviation of the counting statistic. For this study, the instrument
detection limit (IDL) of the spectrometer was calculated as three
times the standard deviation of the counting statistic. It is impor-
tant to note that the magnitude of the counting error, and thus
the lower limit of detection, is directly related to both the total
number of X-rays counted and the number of X-rays due to in-
terference and background. Thus, the IDL varies as a function of
both measurement time and sample matrix. For example, as
shown in Table 1, the IDL for Pb at each site is 120 mg/kg (Site
A), 75 mg/kg (Site B) and 45 mg/kg (Site C).
In a similar manner, the method detection limit (MDL) can be
estimated from the replicate precision data (Table 2). As noted
above, replicate measurements also include the error due to in-
strumental drift. A comparison of Table 2 with Table 1 indicates
that, in general, MDLs are only slightly higher than IDLs, sug-
gesting that instrumental drift was not a significant source of er-
ror for the XRF analyses.
LEAD (MO/KG)
O.BO
(IVl
XRF
XRF VERSUS TRADITIONAL METHODS:
STATISTICAL TESTS ON PAIRED DATA
Following XRF analyses at each site, a selected number of
ground specimens were sent to the U.S. EPA's CLP for confir-
matory analyses. These samples were analyzed by either ICP or
AA methods. The results obtained were then compared to the
XRF results in order to evaluate the adequacy of the XRF
method.
Figs. 1 through 5 are examples of the scatter diagrams obtained
for XRF versus CLP analyses. To better evaluate the degree of fit
of the data, statistical parameters were calculated. The results of
these analyses are given in Table 3 and include the average relative
deviation (d), relative standard deviation (Sd), t and Wilcoxon
test statistic and the corresponding two-tailed t-test and Wilcoxon
test critical values at the 95% confidence level. Readings below
the MDL and significant outliers were not included in the
statistical analysis.
ZINC (UO/KC)
Figure 2
XRF vs. CLP for Zn in Site B Soil Samples
COPPER (MG/KG)
Figure 1
XRF vs. CLP for Pb in Site B Soil Samples
Figure 3
XRF vs. CLP for Cu in Site B Soil Samples
The average relative deviation (d) represents the degree of
deviation of the data from a one-to-one correlation. For example,
as illustrated in Fig. 2, the XRF versus CLP results show a
positive deviation of about 25% (dashed line) from perfect agree-
SCREENING TECHNIQUES & ANALYSIS 117
-------
ment (solid diagonal line) for Zn concentrations above approx-
imately 1,000 mg/kg. Such deviations are probably the result of
uncorrected matrix effects due to an inadequate number of
calibration samples at higher concentrations. Below 1,000 mg/kg,
the average relative deviation is 0% (see Table 3 and Fig. 2).
Table 3
X-MET and CLP Comparison
ARSENIC (MG/KG)
0.00
100
14
13 -
12 -
II -
10 -
t -
a -
7 -
a -
9 -
4 -
3 -
2 -
1 J
0
Figure 4
XRF vs. CLP for As in Site B Soil Samples
IRON (X)
i 4 a
XRF
Figure 5
XRF vs. CLP for Fe in Site C Tailings Samples
The agreement between the XRF and CLP results was
evaluated using Student's t-test and Wilcoxon's signed-rank test.
The t-test determines whether the means of two normally
distributed populations are the same, while the Wilcoxon test
determines whether two populations are symmetric (same or
similar shapes) and, if symmetric, whether they differ in location.
Since normal distributions also are symmetric, the Wilcoxon test
is probably the preferred test.8 The Wilcoxon test typically is
termed a non-parametric or distribution-free test while the t-test is
appropriate only for normally distributed data.
Through statistical analyses, it was determined that, for all
elements, neither the CLP nor the XRF data were distributed nor-
mally. Rather, the populations more closely resembled log-
normal symmetric distributions. Further, most element distribu-
tions were bimodal. Therefore, the t-test was applied to the log-
transformed data, and the Wilcoxon test was applied to the non-
«ll<.u> t.il
IIU fftriMtfr »MMfi (H/hf)
Hi. 1 U » . 1UO
O W - 11W
1110 - 40)0
n M • 1140
U It . 1000
1000 . 41)0
111. « n « - lo.ooo
tu> c1 n it - 1100
U 0-1)1
C, 0 • 1140
u to • 1110
r. o . iw.ooo
it
u
It
11
10
II
11
11
11
11
11
11
-It 11
-t u
» II
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0 11
» 11
» tl
II »
It M
.It 111
10 10
I 11
tM 111
iti m
0> IM
101 «
UI 111
0> III
» M
in- m
in no
»i m
ui« iti
lit 110
Ml
10*
111
III
tl*
11
in*
ttf
III
lu-
ll!
1
•O.M
•I.TI
«.!»•
I.W
•O.M
1.10
I.U
t.Wt
l.»
-1 tl
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0.11
..»
«*
M*
i.n
Hi
Ml*
1.11
I*.
1*
1*
1.K
l.tl
I Model 5 (20 Calibration Samples)
• - itfnifkani difference
transformed data. The results given in Table 3 were evaluated as
follows:
• Agreement between the XRF and CLP populations was indi-
cated for values of t between ± t.95. Values of t outside of
± t.95 indicated that the two population means were signifi-
cantly different at the 95% confidence level.
• Agreement between the XRF and CLP populations was indi-
cated for values of W.95 that fell outside of the critical range
of W + and W - (or both W + and W - must be greater than
W.95). For example, from Table 3, a value of W.95 = 171 is
given for Site B Pb. Since this value lies outside of the W- -
203 and W + = 358 range, the means of the two populations
do not differ significantly at the 95% confidence level.
As indicated in Table 3 by the asterisk, both statistical tests in-
dicate significant differences in the two methods only for Pb at
Site C and Cu and Zn at Site B.
SIGNIFICANCE OF THE NUMBER
OF CALIBRATION SAMPLES
To correct for absorption or enhancement interferences, an
adequate number of calibration samples must be included in the
regression model. The exact requirements will depend on the
number of potentially interfering elements, their concentration
range(s) and the requirements of the particular investigation. The
greater the knowledge about how a sample matrix varies at a par-
ticular site, the more sophisticated the calibration model can be
and, therefore, the more accurate the results.
To address the significance of the number of calibration
samples, five different models were developed for Site C. Each
model (1 through 5) covered similar analytical ranges but had pro-
Table 4
Site C Zinc versus Number of Calibration
4 (I) 10 («)
t.TMl
1.0
1
1
1
t
1
.
10
It
10
to
11
11
11
11
11
-II
It
It
It
10
111 ill ui til -i.n t.n
U III HI 111 O.M >•*
11 191 Ml 141 O.U l.M
» 10, »5 ,« I.M •*
10 III IM III l.tO I-W
1 18 SCREENINO"TECHNIQUES & ANALYSIS
-------
gressively larger numbers of calibration samples. The results ob-
tained for each model then were compared to the corresponding
CLP results. As shown in Table 4, a significant improvement in
the comparison for Zn occurred between model 1 (5 calibration
samples) and model 2 (10 calibration samples), but the relative im-
provement became decreasingly less above 10 calibration samples.
This same trend was observed for the other Site C elements and
indicated that at least 10 calibration samples were necessary to
adequately analyze the samples (i.e., to correct for the variation
in matrix element concentrations), but more than 10 probably
were not necessary.
ANALYSIS OF VARIANCE
The purpose of this section is to address the various sources of
error associated with the XRF analytical technique. The
magnitude of these errors, as measured by their variances (S2),
then can be evaluated for the statistical significance relative to the
overall variance of each element (contaminant) within the sample
environment. In this way, it is possible to determine whether or
not the XRF technique can distinguish between different concen-
trations of an element within a contaminated area and, therefore,
whether the technique is valid for screening analysis.
For this determination, total variance was broken down into
three components, as shown by:
SZTot = S2Sample + S2Calib + S2Anal (1)
where each variance component was evaluated as follows:
• Sample variance (S2 sample) was determined from the concen-
tration distribution of the entire population.
• Calibration variance (S2 Calib) was determined from the stan-
dard deviation (SD) of the calibration curve (Table 1). This
variance included both the error due to uncorrected matrix ef-
fects and the error due to the uncertainty in calibration sample
concentrations.
• Analytical variance (S2 Anal) was determined from the stan-
dard deviations of both replicate precision (Table 2) and sample
preparation. This variance included instrumental (counting)
error, drift error and error due to the nonhomogeneity of the
ground specimen.
Homogeneity was determined by analyzing separate aliquots of
the ground specimen. The standard deviation obtained from the
analysis was of the same order as that obtained for the replicate
precision analyses. Therefore, the error due to powder
nonhomogeneity was negligible for these samples.
The percentage of the total variance of each component is
shown in Table 5; the variance due to the samples (S2 Sample) is
by far the primary component in all cases. Calibration variance
(S2 Calib) and analytical variance (S2 Anal) are relatively minor.
This result indicates that the XRF technique is adequate for
distinguishing between different concentrations of the con-
taminants at the three sites. In other words, the error due to the
X-MET calibration and analysis is insignificant relative to the
total variance of each element.
CONCLUSIONS
The data presented in this study indicate that the portable
X-ray fluorescence technique is suitable for screening As, Pb, Cu,
Zn and Fe in soils contaminated with mine wastes. The XRF ver-
sus CLP comparisons show no statistically significant differences
between the two analytical results for these elements over most
concentration ranges. As determined by the components of
variance analysis, the errors resulting from the XRF method are
minor compared to the sample variance at each of the three sites.
This result illustrates the ability of the XRF method to
discriminate between different contaminant levels under the
highly variable concentration conditions likely to be encountered
at mining waste sites.
Table 5
Analysis of Variance
Site
Site A
Site B
Site C1
Element
Pb
Pb
As
Cu
Zn
Pb
As
Cu
Zn
Fe
Percent
S2 Saaple
100
90
94
95
86
76
64
87
98
99
of Total Variance
S2 Calib. S2
0
9
5
4
14
24
19
12
2
1
Anal.
0
1
1
1
1
0
17
1
0
0
1 Model 5 (20 Calibration Samples)
The results confirm the importance of obtaining an adequate
number of calibration samples in order to model the matrix varia-
tions present within the samples. For Site C, at least 10 calibration
samples were necessary to correct for sample matrix effects.
Although more than 10 samples did further improve the calibra-
tion, the degree of improvement was not significant, especially in
light of the intended screening use of the XRF technique.
For the three sites discussed in this paper, a total of about 1,000
soil/tailings samples have been analyzed with the X-MET 840
X-ray fluorescence analyzer. These analyses have helped establish
heavy metal relationships, including both the spatial extent and
relative degree of contamination. The ease of sample preparation
and analysis in the field (i.e., rapid turnaround times) has been in-
valuable for on-site coordination of field sampling activities.
Also, selection of more representative sample sets for further
CLP characterization has been achieved. These advantages have
made XRF screening for heavy metals a very cost-effective means
of maximizing the amount of information obtained from a field
sampling campaign.
REFERENCES
1. Mernitz, S. and Olsen, R., "Use of Portable X-ray Analyzer and
Geostatistical Methods to Detect and Evaluate Hazardous Materials
in Mine/Mill Tailings," Proc. National Conference on Management
of Uncontrolled Hazardous Waste Sites, Washington, DC, 1985,
107-111.
2. Furst, G.A., Tillinghast, V. and Spinier, T., "Screening for Metals at
Hazardous Waste Sites: A Rapid Cost-Effective Technique Using X-
ray Fluorescence,'' Proc. National Conference on Management of Un-
controlled Hazardous Waste Sites, Washington, DC, 1985, 93-96.
3. Kendall, Lowry, Bower and Mesnavos, "A Comparison of Trace
Metal Determinations in Contaminated Soils by XRF and ICAP
Spectroscopics," U.S. EPA National Enforcement Investigations
Center.
4. Russ, J.C., Fundamentals of Energy Dispersive X-ray Analysis,
Butterworths and Co., Ltd., 1984, 308.
5. Jenkins, R., Gould, R.W. and Gedcke, D., Quantitative X-ray Spec-
trometry, Marcel Dekker, Inc., New York, NY, 1981, 586.
6. Tertian, R. and Claisse, F., Principles of Quantitative X-ray Fluor-
escence Analysis, Heydon and Son Ltd., 1982, 385.
7. Dzubay, T.G. Ed., X-ray Fluorescence Analysis of Environmental
Samples, Ann Arbor Science, Ann Arbor, MI, 1977, 310.
8. Bradley, J.V., Distribution-Free Statistical Tests, Prentice-Hall New
York, NY, 1968, 388.
SCREENING TECHNIQUES & ANALYSIS 119
-------
Field Methods and Mobile Laboratory Scenarios for
Screening and Analysis at Hazardous Waste Sites
G. Hunt Chapman
Ecology and Environment, Inc.
Dallas, Texas
Paul Clay
NUS Corporation
Arlington, Virginia
C. Keith Bradley
U.S. Environmental Protection Agency
Dallas, Texas
Scott Fredericks
U.S. Environmental Protection Agency
Washington, D.C.
ABSTRACT
Field Investigations Teams have developed field sampling and
analysis techniques that have effectively assessed field conditions
at hazardous waste sites for specific contaminants and data qual-
ity objectives to supplement the U.S. EPA Contract Laboratory
Program.
Methods and protocols currently used for field screening of
volatile organics, semi-volatile organics and metals are discussed.
Other methods for Non-HSL parameters (TOC, TOX and RCRA
compatibility testing) and their potential for use to support
various field screening objectives are discussed.
Three levels of mobile laboratory capability are described and
compared to commercially available laboratories.
INTRODUCTION
The purpose of this review is to discuss proven methods for
field analysis of environmental samples at hazardous waste sites.
Other analytical methods that could complement currently used
Field Investigative Team (FIT) procedures are discussed as well.
Scenarios utilizing various configurations of methods and instru-
ments in mobile laboratories also are discussed. These topics are
presented in greater detail in a comprehensive FIT document en-
titled "Field Investigation Team Screening Methods and Mobile
Laboratories Complementary to Contract Laboratory Pro-
gram.'" That FIT document also discusses innovative sampling
techniques such as soil-gas sampling and air sampling that are not
discussed in this review. The reader is referred to that document
for discussions of these sampling techniques and a more thorough
discussion of analytical methods for field analysis and screening.
Various U.S. EPA Field Investigation Teams (FITs), con-
tracted to investigate hazardous waste sites, have developed
highly effective analysis techniques for screening for certain con-
taminants. Methods of organic analysis employ gas chroma-
tography (GQ. Several brands of GCs have been successfully used
by the FIT in the field. Each has different capabilities and degrees
of portability; however, the basic functions of all GC instruments
used are the same. Table 1 lists some of the major differences of
the GCs used by the FITs.*
*Trade names and company names are used for identification only and
do not imply endorsement by Ecology and [-nvironment, NUS or the U.S
EPA.
Metals analysis has been accomplished through the use of an
x-ray fluorescence (XRF) spectrophotometer. The XRF methods
used have the advantages of rapid analysis and small sample
volume requirements.
HAZARDOUS SUBSTANCE LIST METHODS
Hazardous substance list (HSL) compounds currently are
analyzed in the U.S. EPA Contract Laboratory Program. This
list contains over 130 organic compounds, 24 metals and cyanide.
Organic HSL compounds are analyzed by gas chromatography/
mass spectrometry (GC/MS) in the CLP laboratories. The mass
spectrometer allows confirmation of all HSL compounds, even in
very complex samples, i.e., samples with many interfering peaks
such as oil wastes.
The organic field analysis methods described in this section and
presently used by the FITs use gas chromatography alone. Conse-
quently, mass spectrometric confirmation is not available. A
degree of confirmation can be performed in the field by using a
second, different GC column. However, this becomes very dif-
ficult when analyzing complex samples containing many interfer-
ing peaks. In addition, many GCs used in the field lack the resolu-
tional capabilities of more expensive non-portable GCs found in
the CLP labs. For these reasons, it is necessary to determine,
through prior sample analysis and/or historical information, the
expected contaminants that are at a site before this level of field
screening is performed. By knowing what to expect at a particular
site, specific standards can be prepared and samples can be
analyzed for these contaminants of concern. However, the field
screening methods also can be used to locate areas containing
unknown contamination. These samples can be sent to a CLP l»b
for complete GC/MS analysis and confirmation. Thus, the field
methods currently used by the FITs can be used to either analyze
for specific contaminants or to screen sites containing unknown
contamination.
Field analysis of metals by x-ray fluorescence does not suffer
from the interferences described above for organic analysis. Dur-
ing the XRF analysis, each metal present in the sample fluoresces
at a unique wavelength. The XRF instrument is programmed to
select the specific wavelengths for each metal of concern. For this
reason, prior knowledge of metals contamination is not required.
120 SCREENING TECHNIQUES & ANALYSIS
-------
Table 1
Comparison of Gas Chromatographs Used by Field Investigation Teams
tm.
OVEN TW RANGE
POWER
DETECTION LIMITS*
SPECIAL FEATURES
1
| AID-511
1
| Shtadzu Hlnl-2 & M1n1-3
I
| Photovec todel 10A10
I
| rNu motel QC-301
|
| OVA model 128
er*1ent-200'C
a*1ent-390'C
a*1ent
a*1ent-300'C
aifcient
battery/115 VAC
115 VAC
battery/115 VAC
battery/115 VAC
battery/115 VAC
1 pg CQ4 (ECO), .05 ppn propane (FID)
.2 pg -BHC (ECD), 0.01 coulonb/g (FID)
0.1 ppb benzene (PID)
5 pg benzene (PID). 100 pg benzene (FID)
0.2 ppn benzene (FID)
Interchangeable detector modules
tanp. programme; separate 1nj/delj
tenps.; capillary colum capability I
very portable
*Manufacturer's specifications
pg = picograms
ppb = parts per billion
ppm = parts per milllion
coulomb = unit of electrical current
In all field analyses, standard quality assurance/quality control
(QA/QC) is employed. This procedure includes use of appropri-
ate standards to calibrate instruments in the expected operating
range. Method blanks are used to check for laboratory con-
tamination and cross contamination of samples. At least 10% of
all samples within each matrix type (soil, water or air) should be
spiked with the compounds of interest and also run in duplicate to
document the accuracy and precision of the method. A complete
discussion of QA/QC procedures used by the FITs is in the
aforementioned FIT document.1
Volatile Organics in Soil and Water
Samples are collected in 40 ml septum vials and analyzed by the
head space technique. If CLP confirmation of positive results is
desired, duplicate vials should be filled when sampling. In this
way, identical samples can be sent to the CLP for confirmatory
analysis without resampling. Water samples can be collected leav-
ing approximately 25% head space, or the vials may be completely
filled and a syringe inserted through the septum to withdraw exactly
25% of the total volume.
Soil samples are weighed and carbon-free water is added to
leave a 5 ml head space. After sonication for 1 hr, the sample is
analyzed on a "wet weight" basis.
Volatile Organics in Air
Air samples can be collected as grab samples in sampling bags
or as composite samples using adsorbents. The FIT has used ac-
tivated carbon and Tenax® adsorbents successfully to collect
composite samples. Prior knowledge of the type of contaminant
is helpful when choosing the particular adsorbent to use. Each has
different characteristics and is best suited for specific kinds of
compounds.
Grab samples can be analyzed by direct injection using a gas-
tight syringe. Composite samples can be thermally desorbed using
a desorption unit in the field (Century Programmed Thermal
Desorber Model PTD-132A, or equivalent) followed by GC
analysis. Adsorbents can be used to concentrate the contaminants
of concern allowing for increased sensitivity and lower detection
limits.
Acid, Base/Neutral Organics in Soil and Water
Field analysis for semi-volatile organic compounds requires gas
chromatographs capable of maintaining an oven temperature
above ambient temperature. This requirement precludes the use
of several of the GCs listed for volatile analysis. The FIT has suc-
cessfully used the AID-511, Shimadzu Mini-2 and Mini-3 and the
HNu GC-301 for semi-volatile analysis.
Thus far, field analysis of semi-volatile compounds in water
and soil has been limited mainly to polycyclic aromatic hydrocar-
bons (PAHs). The sample preparation and analysis is based on
modifications to EPA Method 610. The PAHs are extracted into
methylene chloride by mixing followed by a silica gel column
cleanup to remove potential interferences. The lower limit detec-
tion for PAHs is between 50-500 mg/kg for soils depending on
the particular compound of interest.
Pesticides/PCBs in Soil and Water
The Electron Capture Detector (ECD) has provided a very
selective technique for field GC analysis of pesticides/PCBs. The
FIT has found the AID-511 and Shimadzu GCs to be very
satisfactory for this purpose.
The field analysis method for pesticides/PCBs in soil requires a
hexane extraction and subsequent GC-ECD analysis. The detec-
tion limit for pesticides in soil is approximately 20 jig/kg.
Pesticides/PCBs analysis in water samples requires a liquid-
liquid hexane extraction followed by GC-ECD analysis. The de-
tection limits for pesticides and PCBs in water are 100 ^g/1 and
200 jtg/1 respectively.
Metals in Soil and Water
Field analysis has been performed using the Kevex 7000 x-ray
fluorescence (XRF) spectrophotometer for the following
elements: chromium, barium, cobalt, silver, arsenic, antimony,
selenium, thallium, mercury, tin, cadmium and lead.
Due to fundamental limitations of the XRF technique, it is not
possible to analyze for beryllium and boron. Aluminum is not
analyzed due to low instrument sensitivity to this element.
Simultaneous detection of all elements analyzed is one of the
greatest advantages of XRF. X-ray fluorescence also has the ad-
vantage of being sample-conservative. Atomic absorption (AA)
and Inductively Coupled Argon Plasma (ICAP) require destruc-
tion of the sample for analysis, whereas the XRF sample remains
virtually unchanged and can be stored for future reference.
Samples of almost any medium can be run, and only a very small
quantity (one gram of soil or 50 ml of water) is needed. Sample
preparation can be used to preconcentrate the sample to decrease
detection limits. This procedure requires a greater quantity of
sample, but such preparation is seldom necessary. The detection
limits will vary for each metal; for example, the detection limit for
lead is approximately 75 /*g/l in water and 20 mg/kg in soil.
SCREENING TECHNIQUES & ANALYSIS 121
-------
NON-HSL PARAMETERS
Non-HSL parameters are not included in the regular CLP pro-
tocol and are not currently used by the FIT. They are presented to
suggest alternatives to CLP analysis for specific applications.
Two groups of tests for non-HSL parameters are discussed here.
The first group consists of tests required by RCRA for classifica-
tion of wastes as hazardous or non-hazardous. The second group
consists of tests that may be used for certain samples for rapid
non-specific screening to locate areas suspected of containing
hazardous wastes.
RCRA-Related Methods
Sampling inspections at hazardous waste sites sometimes
generate potentially hazardous waste, usually from drill cuttings
and water from monitoring well installation. Such wastes are
governed by RCRA regulations and must be handled accordingly.
Due to the scarcity of approved RCRA disposal facilities for
hazardous wastes, such wastes often remain in sealed containers
on-site until an approved facility can be located. Non-hazardous
wastes do not require special handling and may be disposed of in
a typical manner. Therefore, the ability to determine whether or
not a waste is hazardous through rapid analysis would be a
valuable tool.
The tests required by RCRA to determine the hazardous nature
of non-specified (in Appendix VIII) wastes are ignitability, cor-
rosivity, reactivity and EP toxicity. In addition, wastes must be
analyzed for PCBs and dioxin. The feasibility of performing each
of these tests in the field is discussed in the FIT document.' These
procedures are not modified for field screening (with the excep-
tion of PCBs) and therefore would require the support of a fairly
sophisticated mobile laboratory.
Non-Specific Screening Methods
Two useful non-specific screening methods are Total Organic
Carbon (TOQ and Total Organic Halides (TOX). These tests do
not identify specific organic compounds; however, when used in
conjunction with other analytical procedures (GC and XRF), they
may aid in rapid site characterization.
Because soils (and some waters) have a large amount of natural
organic carbon, the usefulness of TOC may be limited and care
must be used in interpreting these data. In contrast, TOX only
measures the organically bound halides (chlorine, bromine and
iodine) in the sample, and the background concentrations of these
are much lower. Therefore, TOX could be used to rapidly locate
areas containing PCBs, chlorinated pesticides and chlorinated
solvents. Once a suspected area was located using TOX results,
GC analysis could be used to identify and quantitate specific con-
taminants.
LABORATORY SCENARIOS
Field analysis can be performed through a variety of ap-
proaches depending on the data quality objectives of the sampling
mission. In this study, three levels of mobile laboratory capability
are presented based on various data quality objectives. Cost
estimates for procuring and operating government-owned,
contractor-operated mobile laboratories also are provided. A
limited comparison between these cost estimates and three con-
tractor bids for a medium-level (Level 2) scenario was conducted.
Implementation of a mobile laboratory operation would require a
more thorough analysis of the cost implications and economic
feasibility; however, the costs and economic evaluations
presented are considered acceptable for planning and budgetary
purposes.
Cost estimates in this study are based on assumptions concern-
ing variables such as analysis time. Assumptions used for cost
estimates for each scenario are presented in conjunction with the
scenario.
Level 1
The highest-level data quality objective considered here is CLP-
level data. These data would be obtained using identical protocols
as used in the CLP laboratories and would provide the same level
of quality. These field data would require neither confirmation by
a CLP laboratory nor prior knowledge of site contaminants.
However, it is good QA/QC procedure for any laboratory to
cross-check results periodically with other laboratories.
U.S. EPA methodologies would be used, and U.S. EPA QA/
QC protocols for CLP data would be implemented. However,
this level of quality would prevent immediate reporting of results.
The effort required to comply with current CLP protocols would
require at least a I- to 5-day analysis time between sample collec-
tion and data results. Depending on the complexity and number
of samples, this lag time could increase substantially. As an
estimate, an analysis rate of six samples/day is projected. This
rate assumes that the laboratory is operated for two 8-hr shifts per
day. This rate is based on an average and is more accurately de-
fined as 30 samples/week. In other words, after the laboratory is
set up and functioning, if 30 samples were received on the first
day, the results could be provided by the fifth day.
The equipment required for a Level 1 mobile laboratory is iden-
tical to that required for a typical CLP laboratory. To meet the
typical litigation requirements of the U.S. EPA, no modification
of the methods or the contract statement of work would be accep-
table. Table 2 lists the major instruments needed and their ap-
proximate costs. This list is presented as a general guide, and the
prices listed are estimates only.
Tahiti
Cools of M«Jor Eqalpncnt for Mobile Laboratories
Cost (I)
{pulp
«t
Level
3
K/HS, *m itllm piirfe ** tr*
(volatile «rf«1ct). >f*
BC/NS, aiti *jite» Mto-iH»ler
(M»l-wUl11«)
CC/lM Trap OetecUr, eitt lyttm
(nlatlle oranilci). art
et/Io. Tre» DetecUr. aiti lyitea
(wl-nUtlle aaeljili)
K-fCO (wt«-l«*1tr M»tlCldet/»Cil)«
6C-FIO (termini)*
t K-FID (volatile a toil-volatile
oraMltt)
ICtf (Mtllt)
MS-eraaklle firaaco
Dwnmtef
TOC anetyter (uretnlnf for total
erfMlc CMceotretio*)
TO! analyier (tcreentaf for aeleanate*
BO. 000
M
40.000
25,000
M
100.000
50.000
M
10.000
140.000
B.OOO
10.009
M
M
M
30.000
M
l*,m
*
*
10.000
*
coapowoi)
Fwe two* (orianlc attraction)
fmt hood (wtill tfleeittoiiO
Analytical balance*
Riffle furnace (MM futlon of alfk-
kaiard laaploi)
Orylni oven
(love bo.
Clattnere, tolvontt, Mpvllet, etc.
TOTALS
15,000
1.000
•.000
3.000
1.000
1.000
5,000
50.000
« 70.000
M
e.OOO
M
1.000
M
M
•A
15,000
U 50,000
m
M
•A
l.»3»
*
M
*
10,000
SM.W
•Difference! In price reflect varying detract of capability to meet data quality objective).
122 SCREENING TECHNIQUES & ANALYSIS
-------
The recommended vehicle for the Level 1 scenario would be a
specially designed and modified 40-ft semi-truck trailer which
would require a certified contract driver and semi-type truck to
transport it to and from each site. Ideally, the trailer would be
divided into three sections. One section would be used for receiv-
ing and preparing samples for analysis. This area would contain
the fume hoods, balance, drying oven, glove box, muffle furnace,
sinks and bench space necessary for sample preparation. The se-
cond section would be equipped for organic analysis. This section
would contain the two GC/MS systems, GC-ECD, GC-FID,
TOC analyzer and TOX analyzer. The third section would con-
tain the ICAP and AAS-graphite furnace for metals analysis. The
two instrument sections (organic and inorganic) should be
equipped with air conditioning and heating systems that provide a
positive air flow to help prevent cross-contamination. They also
should have sufficient capacity to replace the air vented through
the fume hoods during sample preparations. This helps maintain
a constant temperature in the laboratory.
To provide electrical power in remote locations, the Level 1
mobile laboratory should include two generators. One would be
used to provide a high-quality power supply for the instruments.
The other generator would be used to run the lights, heating and
air conditioning systems, exhaust fans in the,fume hoods, extrac-
tion equipment and smaller equipment used in the laboratory.
Since the required generators would be quite large, a separate
trailer for these should be considered. The laboratory also should
have the capability to accept power from conventional sources
when available.
A reliable source of water would be required for analysis. A
central reservoir could supply tap water, and a deionization
system also would be included to supply reagent-grade water. For
carbon-free water needed in trace organic analysis, a high-
intensity ultraviolet light/peroxide system could be used.
The vehicle would be fitted with benches specially equipped
with racks and fasteners to secure all equipment stored in the
laboratory. All gases needed for the analytical instruments would
be stored in a centrally located area with easy access for replacing
cylinders. Gas lines would run from this area behind the benches
directly to the instruments to minimize clutter. In general, careful
planning would be required to insure that all space was used in the
most efficient and safe manner possible.
Considering the extreme sensitivity of the instrumentation in
the Level 1 mobile laboratory, the need for a specially designed
suspension system is extremely important. The effectiveness of
this system in reducing the level of vibration during mobilization
is essential to meeting the projected analysis rate and maintenance
schedules of the major instruments.
The estimated purchase cost and modification of the Level 1
mobile laboratory vehicle is between $300,000 and $500,000. For
the purpose of cost analysis, the $500,000 figure is used.
Projected costs of acquiring and operating a Level 1 mobile
laboratory are discussed below. It must be emphasized that these
costs are estimates only. Certain assumptions must be made in
order to present these estimates. These assumptions are:
• The useful life of the instrumentation and mobile laboratory
vehicle is over a 5-yr period.
• For approximately 3 months per year, the laboratory would be
inoperable due to maintenance and calibration requirements.
• A total of 8 days of down time will be required per site for
travel, set up, calibration and restocking of supplies.
• A support warehouse would be needed to house the laboratory
and provide facilities for maintenance and calibrations. Two
support personnel would be required for preparation and ord-
ering of supplies and report preparation.
• Eight chemists would be required to run the laboratory. The
cost of personnel includes salaries multiplied by a factor of 2.2
to cover overhead expenses.
• The average rate of analysis would be six samples/day, operat-
ing with two shifts.
• Maintenance would average approximately $l,000/month.
• Expendable items used would average approximately $2,000/
month.
• The cost of the full HSL analysis by CLP laboratories is as-
sumed to be $l,350/sample. Approximately 180 days per year
would be available for field analysis (9 months at 20 working
days per month).
Yearly operating costs for the Level 1 mobile laboratory,
operating with two shifts, are shown in Table 3.
Table 3
Yearly Operating Costs for Mobile Laboratories
Level
1
Level
2
Level
3
Capital equipment and vehicle 235,600 78,000 24.800
Personnel: [Cost (no. of personnel)]
Chief chemists 198,000(2)
Senior chemists 242.000(4)
Junior chemists 88,000(2).
64,000(1) 66,000(1)
110,000(2) HA
MA 44,000(1)
Per D1em, Trivel, Lodging 95,360 43,200 28,800
Mirehouse:
dentil cost (16.00/sq. ft.)
Utilities (JZ.SO/iq. ft.)
Xeroxing Support:
Support Personnel [Cost (no. of
personnel )]
Service contracts for major Instruments
Contract driver vlth truck
Lab maintenance
Expendable supplies
12,000
5,000
3,000
110,000(2)
36,000
40,000
30,000
36,000
6,000
2,500
M
44,000(1)
5,000
HA
6,000
18.000
4,500
1,875
HA
NA
NA
MA
6,000
12,000
Total Yearly Operating Costs
SI.130.960
1378.700 S187.975
Level 2
The second-level data quality objective is approximate CLP-
level qualitative data, but semi-quantitative data which may re-
quire confirmation by CLP analysis of a percentage of the
samples. Data of this quality may not be litigable, but they are
useful and appropriate for water, soil and air sampling during cer-
tain field investigations and remedial activities.
Modified CLP methods and protocols would be used, allowing
for same-day turnaround of sample results. A conservative esti-
mate of 12 organic and inorganic samples per day for Level 2
analysis is used in this study. This laboratory could analyze low-,
medium- and high-concentration samples but would not be
equipped to handle high-hazard samples (no glove-box). It would
be equipped with mass spectrometers to provide confirmation of
organic analysis results.
Table 2 lists the major pieces of equipment and their approxi-
mate costs. As in the Level 1 mobile laboratory, a separate
GC/Ion Trap x detector system should be used for volatile and
semi-volatile (AB/N) analysis. The Ion Trap® detector is a
relatively new concept in mass spectrometric analysis. It is rugged,
compact and relatively inexpensive; other comparable MS equip-
ment also is available commercially. With mass spectrometric
confirmation capabilities, prior knowledge of site contaminants
would not be necessary.
SCREENING TECHNIQUES & ANALYSIS 123
-------
The approach to metals analysis in the Level 2 laboratory is
very different from the conventional approach of the Level 1
laboratory. The X-ray Fluorescence (XRF) technique is a rapid,
reliable alternative to conventional ICAP or AAS techniques. In
addition, its compact size is well suited for the Level 2 laboratory.
All analytical instruments would be equipped with automatic in-
jectors and sample handling devices to facilitate introduction of
samples for analysis and rapid turn-around of results.
Less space would be needed to house equipment used in the
Level 2 mobile laboratory than in the Level 1 laboratory due to
the modifications made to the analytical procedures. This reduc-
tion is space needs allows the use of a vehicle such as a panel truck
or recreational vehicle modified to serve as a mobile laboratory. A
contract driver would not be needed to move the laboratory to the
site being studied. This would result in simpler logistical re-
quirements and would enable faster mobilization of the
laboratory.
The estimated cost of a 35-ft recreational vehicle is between
$65,000 and $85,000. Modifications to the vehicle would include:
installation of a generator(s); heating and air conditioning
systems; installation of benches, hood and water system; modifi-
cation of the vehicle's suspension; installation of gas lines for the
GCs; and installation of the instrumentation. The estimated cost
of this conversion is between $45,000 and $55,000. Using the high
end of each estimate, the projected cost of the Level 2 mobile
laboratory is $140,000. Yearly operating costs are summarized in
Table 3.
Assumptions used to determine cost estimates and projected
cost savings are similar to those presented for Level 1 and are
summarized in Tables 2 and 4.
Level 3
The third-level data quality objective is semi-qualitative and
semi-quantitative data. A percentage of the samples would have
to be confirmed by CLP analysis. Data of this quality may not be
litigable but are useful for screening purposes. Modified CLP
methods and protocols would be used, resulting in a same-day
turn-around of results. This laboratory could provide screening
for specific contaminants expected to be present based on
previous analyses, but could not provide GC/MS confirmation.
For this reason, prior knowledge of site contaminants would be
needed to analyze specified compounds. Information indicating
complex contaminant mixtures may preclude the use of the Level
3 laboratory. The Level 3 laboratory could analyze low- and
medium-concentration samples. Extremely hazardous samples
could not be analyzed, and samples with a complex matrix or in-
terfering compounds could not be readily analyzed.
The instruments used in the Level 3 mobile laboratory are
designed for basic analysis. Table 2 lists the main instruments.
The two GCs equipped with Flame lonization Detectors (FIDs)
would be used with specific compounds in mind. They should be
equipped with temperature programming and dual column
capability to allow for some degree of confirmation and analytical
flexibility.
The vehicle required for the Level 3 laboratory would be a
modified step-van. The modifications would include: an expand-
ed roof to allow for head room; a generator; and wiring to supply
power to the instruments (capability to use conventional power
supplies would also be included), the heating system and the air
conditioning system to maintain the temperature and laboratory
benches. The cost of the Level 3 vehicle and its conversion would
Table 4
Summary of the Mobile Laboratory Scenarios
Level
1
Level
2
Level
3
Data Quality
Mobilization time
Capital costs
Yearly operating costs
Down-tlme/sHe
Analysis days/year
Analysis rate
litigation quality
pre-planning required
$1.178.000
$1.130.960 (2 shifts)
8 days
180 days
confirmed screening (organic*)
rapid response
$390.000
$378,700
S days
ZOO days
6 samples/day (2 shifts) 12 samples/day
unconfirmed screening
rapid response
$124.000
$187.975
5 days
200 days
12 samples/day (avg.)
Max. samples/year (1) 1032
Cost/sample $1,096
2340
$162
2340
$80
Max. poss. sites/year (2) 20
Cost/sample $9,425
33
$956
33
$475
(1) The "maxlmim number of samples" figure assumes that the mobile laboratory Is stationed at the sane site for the
entire year.
(2) The "maximum possible sites/year: figure assumes that only one analysis day will be spent on-s1t«.
124 SCREENING TECHNIQUES & ANALYSIS
-------
be in the range of $35,000 to $45,000.
The van would be too small for sample preparation; therefore,
a small 15-ft trailer also would be needed. This trailer would con-
tain benches, exhaust hood, electrical power and a heating and
cooling system. These systems would plug into a second generator
in the trailer, which also would be used to run the heating and air
conditioning system in the mobile laboratory. The cost of the
trailer and its conversion would be between $15,000 and $25,000.
The total cost of the Level 3 mobile laboratory vehicle and con-
version would be $79,000. The yearly operating cost of the Level 3
laboratory is summarized in Table 3.
Assumptions used to arrive at operating costs for the Level 3
mobile laboratory are summarized in Tables 2 and 4.
Lease Versus Buy Analysis
An effort was made to obtain daily leasing rates from com-
panies that offer mobile laboratory services on a contract basis.
Price quotes for non-site specific comparative purposes were dif-
ficult to obtain. Moreover, not many mobile laboratory contrac-
tors have laboratories that were equipped like the Level 1, 2 and 3
systems described above. However, based on limited data (three
bidders) for a laboratory comparable to Level 2, the "buy" op-
tion appears to offer significant cost and operational benefits over
the "lease" option. A government-owned and operated (by U.S.
EPA, FIT or other government contractor) laboratory would cost
about $3,800 per day to operate at 50 percent utilization (100
operating days per year). By comparison, three quotes obtained
for a Level 2 contractor-operated laboratory were:
• Company A — $6,000/day
• Company B — $3,600/day
• Company C — $5,000-$8,000/day
The spread of quotes reflects several things: uncertainty as to
specific requirements, unwillingness of laboratory contractors to
provide reliable quotes for study purposes only and the fact that
the layout, contents and capabilities of the laboratories varied,
even though it was claimed by the bidders that they would be able
to meet Level 2 requirements. Furthermore, none of the bidders
would guarantee a daily production rate for comparison.
In conclusion, a comprehensive and reliable lease/buy
economic analysis requires significant effort and would be mean-
ingful only if performed for a specific need and locale. Also, con-
siderable effort would be required to verify that the contractor
laboratories actually meet appropriate level requirements.
CONCLUSIONS
The methods for field analysis developed by the FITs have pro-
ven very useful in meeting the specialized goals of site investiga-
tion. Advantages of on-site analysis are: data interpretation can
direct on-going work through rapid turnaround of results, critical
samples can be prioritized and analyzed and analyses can be op-
timized for a specific site. This procedure can result in better site
characterization and more meaningful samples sent to the CLP
labs for confirmation and litigation purposes.
Table 4 summarizes the three levels of mobile laboratory
capability presented in this review. The "maximum
samples/year" is based on the analysis rate times the total number
of analysis days/year. To meet this goal, the laboratory must re-
main on the same site for the entire year (no travel time). The
"maximum site/year" is based on only one analysis-day per site.
Both of these figures represent obvious extremes that are not
practical. They are presented to demonstrate the comparable
capabilities of the three laboratories.
Any level of field screening or analysis capability must be
justified by the data quality objectives of the field investigation.
Therefore, the emphasis of this review is not to recommend a par-
ticular laboratory scenario, but to help guide decision-makers in-
terested in pursuing field screening and analysis.
REFERENCES
1. Chapman, G.H., Clay, P. Bradley, K., Fredericks, S. "Field Investi-
gation Team Screening Methods and Mobile Laboratories Comple-
mentary to Contract Laboratory Program," 1986, 250 pp. (Available
through Scott Fredericks, U.S. EPA, Washington, DC)
SCREENING TECHNIQUES & ANALYSIS 125
-------
Exploratory Drilling into a Buried
Uncontrolled Drum Disposal Pit
Patrick F. O'Hara
Kenneth J. Bird
William A. Baughman
Paul C. Rizzo Associates, Inc.
Pittsburgh, Pennsylvania
ABSTRACT
Several years ago, a remedial investigation/feasibility study
(RI/FS) was performed at the Lackawanna Refuse Superfund
Site in Old Forge, Pennsylvania. The RI/FS resulted in a recom-
mendation to excavate and dispose of an estimated 15,000 buried
drums and the highly contaminated municipal refuse from an un-
controlled landfill area on the site known as Pit 5. Drilling, sam-
pling and monitor well installation were not performed in Pit 5
during the remedial investigation due to concerns for the safety of
both workers and the public that always arise at the suggestion of
drilling into uncontrolled areas containing buried drums of toxic
materials.
Remedial design for this project was begun during the summer
of 1985. A Value Engineering (VE) study of the project was per-
formed early in the design phase to assess the cost-effectiveness of
various design approaches. The VE study identified the lack of
recent information on the following items as a source of project
uncertainty that could result in inaccurate estimates of the cost
for removal/remediation:
Depth of Pit 5
Extent of contamination within Pit 5
Depth to groundwater/leachate within the pit
Groundwater/leachate quality within the pit
Pit stratigraphy
Those in control decided to perform a subsurface investiga-
tion of the pit to obtain information needed for safe and cost-
effective design of the remedial/removal program and to enable a
more accurate determination of the cost of remediation. Because
of the legitimate concerns for public safety, a specialized drill-
ing technique was designed using technology transferred from
the oil and gas industry originally developed for well installa-
tion through formations containing naturally occurring pressur-
ized toxic gases. A site-specific program for personnel protection
was developed and implemented.
The program was designed in January 1986. The exploratory
program was successfully executed in a period between Feb. 10
and Mar. 21,1986, without significant incident.
This paper will present the design of the drilling and personnel
protection programs, their implementation and the results ob-
tained. Also presented will be recommendations for future pro-
jects which must consider the exploration and sampling of below-
ground uncontrolled highly hazardous environments.
BACKGROUND
Remedial Investigations (RIs) may be performed at "buried
drum sites" without performing drilling and subsurface sampling
into drum disposal pits. Present off-site impacts may be assessed
without drilling into drum disposal pits, particularly if the dis-
posal area already is considered to be highly contaminated.
The work plan for performing the Rl may emphasize deter-
mining the extent of the contamination migration with respect to
potential off-site receptors rather than detailed characterization
of the source(s). In addition, legitimate concerns for occupa-
tional and public health and safety may make investigators hesi-
tant to directly drill and sample buried drum disposal areas.
The need to understand depth, groundwater conditions and
chemical characteristics of a buried drum disposal area may, in
fact, be critical to properly performing feasibility studies as well
as evaluating removal costs, techniques and hazards posed by the
removal activity. It may be argued that prescribing excavation
and removal of a buried drum area without direct knowledge of
required excavation depth, groundwater conditions, chemical
characteristics and stratigraphy in the immediate zone of drum
disposal entails certain risks during remediation that may out-
weigh the risks entailed in exploratory sampling of the drum
disposal zone.
The Lackawanna Refuse Superfund site contains a buried drum
disposal pit which, prior to this study, had not been subjected to
exploratory drilling.
CIRCUMSTANCES AT THE LACKAWANNA
REFUSE SUPERFUND SITE
Paul C. Rizzo Associates, Inc. (Rizzo Associates) is under con-
tract to the U.S. Army Corps of Engineers, Omaha District,
(USACOE) to do remedial design work for the cleanup of the
Lackawanna Refuse Superfund site in Old Forge, Pennsylvania.
The remedial measures to be designed were prescribed in the site
Record of Decision (ROD) issued by the U.S. EPA Region III
administrator.
Problem Areas
The Record of Decision was based upon a remedial investiga-
tion/feasibility study performed in 1983 and 1984 by a U.S. EPA
Zone Contractor. The remedial investigation identified five spe-
cific problem areas to be remediated at the site. These areas are:
• Pits
Pit 5 contains an estimated 15,000 buried drums of undefined
and potentially hazardous materials. This pit was the subject
of an NEIC investigation in 1980 during which several test pits
were dug and several hundred drums were recovered and
assessed. A substantial portion of the contents of these drums
was found to consist of organic solvents. The pit also contains
municipal and commercial refuse.
126 SAMPLING & MONITORING
-------
• Pits 2 and 3
Pits 2 and 3 contain primarily municipal and commercial
refuse.
•Borehole Pit
The Borehole Pit apparently was used for the disposal of bulk
liquid wastes. Only traces of organic compounds have been de-
tected. Contamination, if any, is believed to lie in the top foot
of soil.
• Access Road
Liquids containing heavy metals apparently leaked onto this
road; few organics have been detected. Contamination, if any,
reportedly is confined to the upper foot of soil.
• Paint Spill
A small area of what appears to be spilled paint was found on
the site. High levels of lead have been detected in this material.
The material has penetrated the soil less than 1 ft.
Selected Remedial Alternatives
The selected remedial alternatives for each problem area are:
• Pits
Excavation, disposal of all drums and highly contaminated
wastes off-site, leachate collection and treatment on-site, cap-
ping and gas venting
• Pits 2 and 3
Capping, leachate collection and treatment on site and gas
venting
• Borehole Pit
Excavation and disposal off-site
• Access Road
Excavation and disposal off-site
• Paint Spill
Excavation and disposal off-site
Remedial Design Program
Rizzo Associates initiated design of the remedial action pro-
gram in July of 1985. The conceptual phase of the design work in-
cluded assessments of additional informational needs to properly
complete the design process. Informational needs that were iden-
tified included:
• Depth of Pit 5
• Extent of contamination within Pit 5
• Groundwater level(s) within Pit 5
• Chemical composition of groundwater within Pit 5
• Geotechnical conditions in certain areas of proposed Access
Road relocation
• Subsurface conditions at the site of a proposed leachate collec-
tion trench at the north end of Pit 5
• Location of a buried sluice pipe beneath the west end of the
site access road near the entrance of Pits 2 and 3
Planned Site Assessment
In order to enable completion of remedial design, the USACOE
issued a proposed scope of services to Rizzo Associates for sup-
plementary site investigations on Dec. 24, 1985. The work per-
formed included:
• Preparation of an investigation-specific Health and Safety Plan
• Preparation of an investigation-specific Quality Management
Plan
• Performance of a site reconnaissance and geophysical survey
• Drilling and sampling of Pit 5 (municipal refuse, mine spoil
and groundwater)
• Chemical analysis of samples from Pit 5
• Drilling and sampling of geotechnical borings along the pro-
posed Access Road relocation
• Excavation of test pits at two proposed leachate collection loca-
tions to enable design of the leachate collection system
• Performance of a survey to establish locations of borings and
test pits
The balance of this paper describes the activities related to the
exploration of Pit 5.
HEALTH AND SAFETY AND QUALITY MANAGEMENT
The Health and Safety Plan for this investigation was initially
prepared prior to drilling and finalized to incorporate USACOE
comments in March of 1986.
A short summary of this plan is as follows:
• An industrial hygienist served as the on-site investigation super-
visor and had complete authority over all field activities.
• All site workers participated in medical surveillance programs
and completed site-specific training prior to site activities.
Training culminated with written site-specific examination on
the health and safety program.
• Extensive personnel protective equipment was required for this
project because of the potential hazards associated with site
activities. The equipment included outer acid suits, inner Saran
Tyvek coveralls, three layers of gloves, boots, boot covers and
airline respirators with 5 min. escape capabilities.
• Real-time air monitoring played an integral part of the Health
and Safety Plan. Monitoring was performed with a HNU,
combustible gas meter, hydrogen sulfide meter and hydrogen
cyanide meter. In addition, quantitive personnel monitoring
was performed.
The Quality Management Plan (QMP) for this investigation
was initially prepared prior to drilling and finalized in March of
1986 to include comments from the USACOE. The QMP in-
cluded sampling and chain of custody procedures, analytical
methodology and statistical evaluation of Quality Control Data.
Quality Control Data included calibration, matrix, spikes, dupli-
cates, surrogate standards and independent Quality Control
samples.
FIELD INVESTIGATION
Geophysical screening was performed at Pit 5 using a Scintex
MP-2000 Fluxgate Magnetometer. The magnetometer was used
to indicate relative presence of buried metal (including drums).
The boring locations for Pit 5 were selected based upon represen-
tative distribution within the reportedly deepest portions of the
pit and in areas having lower magnetometer readings than sur-
rounding areas. The purpose of the screening was to minimize the
potential for drilling directly into a drum or drum pocket, partic-
ularly at a shallow depth.
Drilling at Pit 5 was supervised by Rizzo Associates' person-
nel, and the drilling subcontractor was John Mathes Associates.
Drilling was accomplished using a CHE550 hydraulic rotary,
four-wheel drive drill rig with a continuous cavity pump. Potable
water was used as the drilling fluid.
At each boring location, a primary and secondary surface
collar were installed. The surface collar consisted of a 5-ft section
of 4-in. steel pipe used to prevent surface runoff from entering the
borehole and, as explained later, to aid inthe control of gaseous
releases from the borehole. All surface collars were installed with
PVC caps on the bottom to seal off the bottom boring until drill-
ing commenced.
The surface collar holes were drilled with an 11-in. flight auger
to a depth of 4.5 ft. Plastic sheeting was placed around the bore-
holes prior to augering to collect cuttings. Concrete was used to
set the collar and to seal off exposed refuse areas below ground
surface. Continuous air monitoring was performed during auger-
SAMPLING & MONITORING 127
-------
ing, as well as during drilling and monitor well installation.
The surface collars were allowed to set up at least 24 hr before
drilling occurred. Then a device to control liquid and gaseous re-
leases from the borehole was screwed onto the threaded surface
collar, thus making a closed system.
KELLY ROD
r BALL-VALVE OPERATED
SAMPLING PORT
THREADED 41.0. STEEL
SURFACE CASING
(N.T.S.)
Figure 1
Schematic Diagram of Gas Control System Utilized ai Pit 5
(Lackawanna Refuse Site)
The gas control system designed for this project included a
threaded ball-valve which attached to the4-in. I.D. surface collar;
this valve served as the emergency shut-in mechanism in the event
of gaseous release from the borehole (Fig. 1). A steel adapter is
screwed into place above the ball-valve and acts to divert any re-
turn flow of drilling fluids and cuttings through a section of
4-in. flexible corrugated pipe and into an enclosed return tank.
The adapter also has an attached rubber gasket at the top. The
purpose of the rubber gasket is to seal off the annular space be-
tween the casing and the adapter, while allowing the casing to
advance through the gas control system.
Drilling was accomplished utilizing a wireline operated tri-cone
roller bit with a diamond tipped casing advancer (Fig. 2). The
casing was advanced through the stationary gas control system
and surface collar. During drilling, the walls of the boring were
sealed off by the casing and the only downhole open area was
at the bottom of the boring. Water was pumped down the inside
of the casing and out of the drill bit, returning up the annulus
of the borehole or, more typically, lost to the formation.
The purpose of drilling with water was to aid in removal of
drill cuttings from the bottom of the borehole, to mitigate escape
of vapors from the borehole and to lubricate the drilling. Drill-
ing water and cuttings generally were lost to the formation. (Re-
turn for all six borings totaled less than 15 gal). Air monitoring
during drilling indicated that the system was extremely effective
in preventing gas releases. Once the casing penetrated the bot-
tom of the disposal pit, drilling and sampling operations were
continued with negligible releases to the breathing zone.
Soil samples were collected with a 24-in. standard penetration
test (SPT) split-barrel sampler on 5-ft centers. After drilling to
the required sampling depth, the casing was unscrewed at the
surface, above the gas control system. Care was taken to assure
the boring was completely full of water. An overshot latching de-
vice was lowered down the inside of the casing by a hoist-oper-
ated wireline cable. The roller bit and sub were picked up by the
overshot latching device and brought to the surface. The SPT
sampler then was lowered inside the casing attached to AW rods
and the sampler was driven using a cat-head operated 140 Ib
weight.
WIRELINE CABLE
OVERSHOT LATCHING
DEVICE
NW CASING
RETRACTABLE 2 15/16'
TRI-CONE ROLLER BIT
W/ LOCKING INNER SUB
DIAMOND TIPPED CASING
ADVANCER (REAMING SHOT)
(N.T.S.)
Figure 2
Schematic Drawing of Wireline Drill Bit and Reaming Shoe
Utilized at Pit 5
(Lackawanna Refuse Site)
After the SPT sampler was removed from the borehole, the
roller bit and locking inner sub were lowered to the bottom of the
boring by wireline, where they locked into the casing advancer
and drilling continued. Samples were screened using real-time in-
strumentation for radioactivity, hydrogen sulflde, hydrogen cya-
nide, organic vapors (PID) and an explosimeter.
This drilling and sampling method provided a means of obtain-
ing representative soil samples with no collapse of the borehole
walls while preparing to sample. This method also proved effec-
tive in mitigating gaseous vapor releases from the borehole. The
casing effectively sealed the borehole walls while the water in the
borehole contained the bottom of the boring. Any vapors escap-
ing up the annulus were trapped in the return tank where they
could be contained and monitored.
A monitoring well was set at each boring location following
soil sampling. The wells consisted of 2-in. galvanized steel riser
pipe and 2-in. stainless steel well screen (0.01-in.) with PVC caps-
After the final soil sample was retrieved, the weU screen and riser
128 SAMPLING & MONITORING
-------
pipe were lowered into the hole by wireline, with the casing in
place and the borehole full of water. The casing was removed in
sections, and the refuse material was allowed to collapse against
the well.
Pulling casing above the base of the disposal pit generally was
the phase of operations most susceptible to release of gaseous
vapors from the borehole. Measureable amounts of both methane
and hydrogen sulfide were detected for a period of a few min-
utes at one boring during this phase of monitor well installation.
These releases were controlled by filling the borehole with water.
Twenty feet downwind of the boring location, there were no in-
stances of detection of gaseous releases and, therefore, no meas-
ureable off-site releases.
The need to use the emergency shut-in ball valve never arose,
as all gas releases were controlled by filling the borehole with
water. In the event of an uncontrollable gaseous release, the cas-
ing would have been pulled off bottom, unscrewed at the sur-
face and dropped below the surface and the ball-valve closed.
The major drawback to the gas control system utilized at this
site is that unconsolidated garbage and/or soil may collapse
around the bottom of the casing, possibly prohibiting the casing
from being lowered below the ball-valve assembly. This problem
could be remedied by having the ball-valve installed in a short
(1-ft) piece of casing immediately below the kelly swivel. This
adaptation would remove the need to lower the casing below the
ball-valve, and the well could be shut-in at any time during the
operation.
The installation of the surface collars proved to be an impor-
tant part of the drilling process. Surface collars must be vertical
in order to allow the boring to be drilled without major devia-
tion. In one boring location, the surface collar set up slightly out
of level. After the boring depth reached approximately 30 ft, the
boring had to be terminated due to hole deviation.
The use of the tri-cone roller bit and casing advancer with
t
- -
- -
-10-i
-15-
-20—
-25-
!
MJCEF
S-1
X
X
X
X
SAMPLE
RECOVERY (IN.1
5
18
12
te
BLOWS PER
0 IN.
INCREMENT
20-24
25-15
6-15
24-25
6-fl
0-11
4-7
7-10
PROJECT NAM& LACKAWANNA
s>
Ah
BR
BR
CA
we
COORDINATES
N 44fl.22Q.941 E 2.546.790.301
SURFACE EL: flSS.7*
GER CUTTINGS SHOWED BROWN, FINE-MEDIUM
ttD AND S1LTY CLAY. WITH ASSORTED TRASH
ID TIRES (WET AT IS").
OWN. FINE SAND AND SILT (MOIST), CRAY
OWN SANDSTONE FRAGMENTS. BLACK
ABONACEOUS SHALE AND COAL FRAGMENTS,
XX) AND PAPER.
•'BASE OF GARBAGE PIT "14.5'
BROWN, FINE SAND (MOST) DENSE. TRACE
TAN SILT. DARK CRAY SHALE. COAL FRAGMENTS.
OCCASIONAL SANDSTONE FRAGMENTS (SPOIL).
BROWN. FINE SAND AND STLT (MOIST)
MEDIUM DENSE. BROWN HARD SANDSTONE
FRAGMENTS THROUGHOUT. CARBONACEOUS SHALE
AND COAL FRAGMENTS COM WON (SPOtL).
BROWN, FWE SAND (MOST) MEDIUM DENSE. WITH
SANDSTONE FRAGMENTS INTERMIXED. TRACE ,
SHALE FRAGMENTS (SPOIL).
SEE SHEET 2 OF 1
PROJECT NO.: 83-2M
DATE BEGAN: 3-6-M
DATE COMPLETED: 3-7-6«
FIELD EMC./CEOL; WAB/KJB
CHECKED BY; PfO
GWL: DEPTH 1A15' DATE/TIME 3-14--M/075.
1703' OATE/nUE 3-15-86/073
DftHMMC UrmOft WATER ROTARY WITH 2 15/1
TIPPED CASING ADVANCER.
HNU VOLATILE
READING (PPM)
25
40
a
2
0.5
REMARKS
BEGAN DRILLING
3-6-BB/OB40 MRS.
3-4-86 SET 1-4* STEEL
SURFACE COLLAR WITH 11" STEEL
AUGER TO 4.5'.
S-1 LAB SAMPLE (3.0'- 5.0')
(SAMPLED AT AUGER TIP)
NOTE;
'HOLE FILLED WITH WATER TO
3.5' WHILE SETTING COLLAR-NO
WATER ADDED TO CONCRETE MIX
NOTE:
NO RETURN CIRCULATION DUE
TO WATER LOSS IN GARBAGE.
S-2 LAB SAMPLE (B.5'-11.5')
DROVE SPOON 3 TIMES.
S-3 LAB SAMPLE (U.S'-IB.S1)
DROVE SPOON 1 TIME.
HARD DRILLING 14.5'-1B.fl'
EASY DRILLING (VOID) FROM
1B.B'-1B.5'.
S-4 LAB SAMPLE (19.5'- 21.5')
DROVE SPOON 2 TIMES.
S-5 LAB SAMPLE (24.5'-26.51)
DROVE SPOON 1 TIME.
1 NOTES:
it
••s
D
0
140 Ib. HAUMER USED TO DRIVE
T SAMPLER,
OPERATIONS MONITORED
TH HNU OVM, RADIATION MONITOR.
CPLOSIMETER. HCN METER. AND
5 METER. ONLY VALUES
SIGNIFICANCE ARE SHOWN.
t'
X
— J5-
-40-
-45-
-50-
— 55—
gQ
1
&
X
X
X
s$\
X
z
1
19
18
20
17
14
BLOWS PER
6 IN.
INCREMENT
7-«
7-7
4-6
9-14
•-10
20-12
9-10
14-14
B-66
22-12
9-10
14-12
PROJECT NAME: LACKAWANNA
N 446.220.941 E 2.546.790.301
SURFACE EL: 999.7'
BROWN-GRAY BROWN. FINE SAND AND CLAYEY
SILT, WITH TAN-RED BROWN FINE-MEDIUM
SANDSTONE FRAGMENTS. MEDIUM DENSE (SPOft.).
BROWN, FINE SAND AND SILT. WITH BROWN
FINER GRAINED HARD SANDSTONE, TRACE DARK
GRAY-BLACK CARBONACEOUS SHALL SAND IS
MEDIUM DENSE (SPOIL).
BROWN FINE SLTY SAND. MEDIUM
DENSE. WITH INTERMIXED CLAYEY SILT.
RED-BROWN SANDSTONE FRAGMENTS. TRACE
BLACK CARBONACEOUS SHALE (SPOIL).
BROWN SILT AND FINE SAND (MOIST)
MEDIUM DENSE. BROWN AND RED BROWN
SANDSTONE FRAGMENTS. TRACE BLACK
CARBONACEOUS SHALE (SPOIL).
BROWN, FINE SAND AND SLT WITH WEATHERED
BROWN SANDSTONE FRAGMENTS, TRACE BLACK
CARBONACEOUS SHALE FRAGMENTS (MOIST)
VERY DENSE (SPOIL).
BROWN SILT AND FINE SAND, WITH TRACE
CLAYEY SLT. SANDSTONE AND SHALE FRAGMENTS
AS ABOVE. MEDIUM DENSE (SPOIL).
SEE SHEET 3 OF 3
PROJECT NO.: &S-2M
DATE BEGAN: 3-fl-§6
DATE COMPLETED: 3-7-B6
HELD ENC./CEOL: WAB/KJB
CHECKED BY: PFO
CWL: DEPTH JJJi DATE /TIME 3-14-66/0755
17.0? DATE/TIME 3-15-66/0731
DRILLING METHOD: WATER ROTARY WTH 2 15/1
TRI-CONF in 1 Fft HIT WITH NW DIAMOND
TIPPED CASING ADVANCER.
P
I
5g
0
0
0
0
0
0
. J
it
•',«
EX
£
REMARKS
SANDSTONE COBBLE IN SPT
SAMPLER TIP.
OTES:
140 Ib. HAMMER USED TO DRIVE
T SAMPLER.
OPERATIONS MONITORED
TH HNU OVM, RADIATION MONITOR,
PLOSIMETER, HCN METER. AND
£ METER. ONLY VALUES
SIGNIFICANCE ARE SHOWN.
Figure 3 (Continued)
Log of Boring No. P5—4
t
-65—
SAMPLE
*
X
PROJECT NO.:
DATE BEGAN:
g
5. *"
5
12
BLOWS PER
B IN.
INCREMENT
10-14
18-12
13-14
5O-21
PROJECT NAME: LACKAWANNA
SURFACE EL: B55.7*
BROWN FINE SAND AND SILT. WITH BROWN
WEATHERED SANDSTONE FRAGMENTS, MEDIUM
DENSE (SPOIL).
DARK BROWN FINE SILTY SAND. DARK GRAY-
BLACK. CARBONACEOUS SHALE, TRACE DARK
BROWN WEATHERED SANDSTONE. VERY DENSE
(SPOIL).
BOTTOM OF BORING AT 66.5'
NOTE;
INSTALLED 2' MONITOR WELL 3-7-B6
0'-20' 2" GALVANIZED RISER PIPE
20'-30' 2' STAINLESS STEEL SCREEN (0.01')
30'-34' BENTONITE
34'- 58' GRAVEL
5B'-B6.5' COLLAPSED BORING MATERIAL
B5-2DB GWL: DEPTH 19.15' DATE/TIME 3-14-86/075
3-6-86 ,7.02' DATE/HUE 3-15-B6/073
DATE COMPLETED- _tZ^66
FIELD FNC-/CEOL: WAB/KJ
CHECKED BY: PFO
HNU VOLATILE 1
READING (PPM)
0
0
i.
0 I
DRILLING METHOD: WATER ROTARY WITH 2 15/16' j
n TRi-rnwF an i FB BIT. WITH NW DIAMOND E
TIPPED CASING ADVANCER. C
REMARKS
VERY HARD DRILLING 6 3.0'- 6 4. 5'
NOTES:
140 Ib. HAMMER USED TO DRIVE
PT SAMPLER.
- OPERATIONS MONITORED
ATH HNU OVM, RADIATION MONITOR
XPLOSIMETER. HCN METER. AND
2$ METER. ONLY VALUES
IF SIGNIFICANCE ARE SHOWN.
Figure 3
Log of Boring No. P5—4
Figure 3 (Continued)
Log of Boring No. P5—4
SAMPLING & MONITORING 129
-------
water as a drilling fluid along with the gas control system proved
to be both a safe and effective means of obtaining soil and
groundwater data from landfills containing buried drums of un-
identified and potentially hazardous materials.
The drilling, sampling and well installation program took 17
work days and was performed in February and March of 1986.
Air temperatures ranged from 10 °F to 40 °F, with typical lows
in the mid-teens and typical highs in the low 20s. There was one
day lost to bad weather (steady rain at 40 °F). Weather condi-
tions proved close to ideal for working in the personal protective
gear required for the project.
Fig. 3 is a typical log from an exploratory boring. Fig. 4 is a
typical monitoring well installation diagram.
4" 1.0. STEEL PROTECTIVE
CASING WITH LOCKING CAP
ELEV
858.8.
955.2
•S0.t
•35.6
•2S.6.
»216_
DEPTH
— o
0.0-
.^g
GROUT SLURRY — "^ ^
si
CAmMQE/nu M47EHr/u.
(0-tf.f)
«.»'
MME 5PCR.
2«.6'
a*1
/ .. — 1' PVC SCREW CAP (UNVt
t
—
=?
— •
Km
(N.T.S.
-/ /— APPROXIMATE EXIS1
/ GROUND SURFACE
/
:*••' ^ — CONCRETE (4.51)
?.?
ji^ n" DIA. BORING
^ — 3.«2S* DU. BORMC
^ COLLAPSED BORINC M;
_, 2" GALVANIZED STEEL
^^^^ RISER P»«C
^
., — STAINLESS STEEL WELL
.s^ SCREEN (0.01T
^x^ Oa
-------
CONCLUSIONS
The following conclusions can be made:
• Pit 5 at the Lackawanna Refuse site is shallower and less high-
ly contaminated with respect to background than previously
believed.
• Pit 5 contains significant zones of perched water that exhibit
large variations in pheratic level and water quality over rela-
tively short distances.
• Some of the groundwater within Pit 5 exhibits significant con-
tamination related to the drum disposal activities.
It has been confirmed that it is possible to drill, sample and in-
stall monitor wells in a drum disposal pit in a manner that does
not compromise the health and safety of the work force or the
public.
ACKNOWLEDGEMENTS
We appreciate the support of the U.S. Army Corps of Engi-
neers, U.S. EPA Region III, and the citizens of Old Forge, Penn-
sylvania for guidance and assistance with this investigation.
SAMPLING & MONITORING 131
-------
Statistical Approach to Groundwater Contamination
Mapping with Electromagnetic Induction:
Data Acquisition and Analysis
Dennis D. Weber, Ph.D.
Environmental Research Center
University of Nevada, Las Vegas
Las Vegas, Nevada
George T. Flatman
U.S. Environmental Protection Agency
Las Vegas, Nevada
ABSTRACT
A field-to-finish procedure to quantitatively measure electrical-
ly conductive subsurface contamination with surface elec-
tromagnetic induction (EMI) is described. The procedure exploits
the rapid data acquisition feature of EMI to build a statistical
data base for data processing and interpretation, where inverse
modeling is the core of the interpretation technique. The
statistical approach validates and enables the use of statistical
diagnostic tools to test and guide the otherwise intractable inverse
modeling process. This paper focuses on the use of those
statistical diagnostics in the interpretation process. To evaluate
the final results of inverse modeling, a comparison is made with a
vertical cross-section obtained from a set of vertical logs taken
with a borehole induction logger. This study shows, by way of a
case study, some capabilities and limitations of the EMI method
and the results of inverse modeling of 116 vertical soundings. The
degree of detail to which EMI can describe the subsurface using
the statistical approach is shown.
INTRODUCTION
Detecting and monitoring subsurface contamination is accom-
plished by either direct measurements from monitoring wells or
by remote sensing surface geo-electrical probing and soil organic
vapor analysis. Geo-electrical probing often uses electromagnetic
induction that measures the electrical conductivity of the earth to
obtain information about the subsurface. Data acquisition is
either profiling (or gridding), in which a series of measurements
are made at one instrument configuration at regular sampling in-
tervals along a transect (or along parallel transects in the case of
gridding), or vertical sounding, in which a set of measurements
utilizing all available instrument configurations is made at
selected station locations. Profiling data can be interpreted in rare
cases where the subsurface structure is known to be homogeneous
and isotropic and where the data are free of cultural noise. In
most cases, however, the subsurface structure is neither known
nor well behaved so that the vertical sounding technique must be
used to model the structure and to extract the contamination
value from the model. Techniques for analysis and interpretation
of geo-electrical soundings have been developed and generally are
successful, but these applications have involved deeper targets (oil
and minerals) than in hazardous waste studies. Most targets here
are located in the aquifer which can be found from the surface to
tens of meters below the surface, whereas in the mining and
petroleum studies, the targets can be hundreds to thousands of
meters below the surface.
In hazardous waste studies, most reported case studies using
geophysical surface measurements have involved only profiling.
The interpretation of the resulting measurements is difficult
because of noise, a need to know the subsurface structure and a
need to understand the instrument response. Electrical soundings
have been used for these applications,' but the problem was not
treated consistently in a manner that addressed the special prob-
lems inherent in hazardous waste studies. This paper presents a
method of using Electromagnetic Induction in a field-to-fmish
procedure that addresses the problems of cultural and geological
noise, low instrument resolution and anisotropy and inhomogene-
ity of the subsurface. The procedure involves a consistent
statistical approach that takes advantage of a sophisticated verti-
cal sounding interpretation program (Inverse Modeling) and
allows data processing of the raw field data. This procedure pro-
vides a system of internal and external checks on the otherwise
obscure Inverse Modeling procedure and hence guides the in-
vestigator in the analytical process.
OBJECTIVES
The primary objective of this paper is to illustrate the efficacy
of a statistical approach to Electromagnetic Induction (EMI) sur-
face geophysical remote sensing in the detection of electrically
conductive subsurface contamination. The approach attempts to
exploit the advantages of EMI to mitigate the problems of surface
geophysical probing and to provide valid and consistent data for
interpretive procedures. Furthermore, the use of statistical
diagnostic output from Inverse Modeling to guide interpretation
of the modeling process is examined. For evaluation, a com-
parison of the information obtained from the use of computer in-
verse modeling is made with results obtained from a borehole in-
duction logger.' A further objective was to examine the limita-
tions of the EMI surface probing method in cases involving high
subsurface conductivities. The case used to meet the objectives in
this study involves an electrically conductive groundwater con-
tamination plume that resulted from chemical wastes being
dumped into unlined surface containments.
STATEMENT OF THE PROBLEM
The problem of measuring electrically conductive subsurface
contamination by EMI is complicated by a number of factors in-
cluding: (1) instrument limitations, (2) cultural interference and
(3) the inherent non-uniformity of the subsurface geology. Instru-
132 SAMPLING & MONITORING
-------
ment limitations arise because of the nature of the elec-
tromagnetic fields and the difficulty of isolating the signal from
the primary field which lead to a low signal-to-noise ratio and a
relatively low vertical depth resolution. The vertical response of
the instruments allows a relatively high resolution for the top 3 m,
but an increasingly lower resolution with increasing depth.
Although more suitable instrumentation could be designed for
shallow applications, the resolution most likely would not be
greatly improved. Examples of cultural interference are buildings,
fences and buried metal as well as electrical noise caused by radio
stations, machinery and power lines. The effects of some of these
can be mitigated by an increased signal-to-noise ratio which again
required improved instrument design that invariably leads to com-
promises in other areas. The third factor requires the most in-
genuity in interpretation. The earth is inherently complex because
of complicated layering structure, inhomogeneity, anisotropy and
geological noise, and, to further complicate matters, the geology
can vary greatly over a few meters. The varying geology can be
referred to as producing a spatial variability having a short range
of correlation, a fact that we will use later in our analysis. The
complexity means that the subsurface rarely is comprised of
several thick, flat, homogeneous and isotropic layers. Further-
more, geological noise (small volumes of earth having significant-
ly different physical and electrical characteristics) can make the
problem of understanding the picture most difficult.
Sophisticated two and three dimensional modeling techniques
have been studied with varying degrees of success, but the com-
plicity of these studies precludes them from most hazardous waste
studies because of time, money and expertise requirements.
APPROACH
Our approach is to accept the above limitations and to use
available instrumentation and a one-dimensional modeling tech-
nique that allows the use of straightforward data acquisition, data
processing and data interpretation. Effects of noise and low
resolution will be mitigated with improved data acquisition and
processing. This translates to obtaining sufficient data to allow
digital filtering techniques to reduce noise effects in the measured
data and to provide statistical input to the interpretation process.
The EMI instruments lend themselves to this approach, because
data acquisition is fast and can be taken in physically relatively
small areas. To mitigate the two and three dimensional effects
that will be lost in the one dimensional analysis, consideration will
be given to the spatial correlation of the variables in the inter-
pretation.
The model shown in Fig. 1 is the basis of the interpretation that
will be used in this study. In this model, we assume that the sub-
-40m-
-20m-
4 10m h
O - Q
t
T1
T2
T3 =00
P
°2 = °A
°3
Vadose Zone
Aquifer
Aquiclude
Figure 1
Simplified 3-Layer Model Used in Inverse Modeling. Examples
of 10, 20 and 40 m Coil Configurations Are Shown at Station P.
surface is comprised of several layers, all of which are one-
dimensional; they are flat, and the electrical properties are con-
stant over the entire volume. This is equivalent to saying that each
layer is homogeneous throughout its thickness and isotropic
horizontally in all directions. A model such as this is a necessary
simplification in view of the low resolution of our geophysical
technique, and it allows us to apply standard data interpretation
techniques to determine the model parameters. Here the
parameters are the layer thicknesses and the layer conductivities.
The second layer will represent the aquifer and, in general, it will
be the conductivity of this layer that is of interest. In our model-
ing procedure, however, all parameters initially will be calculated.
PROCEDURE
The procedures used in this study will be illustrated by example.
A site in Pittman, Nevada (Fig. 2) with a documented ground-
water plume was used. The contamination originated from
organic and inorganic chemical wastes that were dumped into
unlined surface containments beginning in about 1945 and subse-
quently entered the groundwater. The transect selected for this
study crosses the groundwater plume about 2 km from the source.
Total dissolved solids concentrations of 20,000 mg/1 were
measured by direct sampling of water samples from monitoring
wells along the transect.
Athcni Av«nu« |
~W\
i3o
SunMtRoad
T T T T Power Llnei
«»<»«.>«. Fence
Figure 2
Case Study Site at Henderson, Nevada, Showing the Pittman
Transect. Cultural Noise Sources Relating to the Study Are Shown.
Instrumentation
The instruments used in this study were the Geonics EM31 and
EM34-3. These units, although not designed for sophisticated
sounding applications, are electrically stable, dependable and af-
ford a reasonable range of coil configurations. A coil configura-
tion in this paper will refer to a particular combination of coil
separation and coil orientation. The set of configurations here are
3.7, 10, 20 and 40 m coil separations at both the horizontal and
vertical dipole mode, for a total of 8 unique configurations. The
EM31 has a fixed coil separation (3.7 m) and can be held at
several heights above the ground for additional depth informa-
tion.
Data Acquisition
Data were taken along the 1200 m transect (Fig. 2) in the sound-
ing mode at intervals of 10 m. The sounding mode requires multi-
ple measurements at each station, hence a measurement was made
every 10 m with each coil configuration with the EM34-3. These
were 10, 20 and 40 m coil separations using both vertical and
horizontal dipoles giving a total of 6 measurements.
SAMPLING & MONITORING 133
-------
Measurements were made every 5 m with the EM31 at 0 and 1 m
heights above the ground with both horizontal and vertical
dipoles. The EM31 measurements were taken each 5 m because of
the shorter coil separation and the higher spatial variability of the
surface layer to which the shorter coil separations are sensitive. A
total of 960 EM31 measurements and 720 EM34-3 measurements
were made in one man-week of field time.
Fig. 3 shows a sample plot of EM34-3 10-m field data for the
first 60 stations. The data density allows an immediate visual
analysis for electrical and geological noise. Comparison of the
curves for the vertical and horizontal dipoles shows that, for ap-
parent conductivities over about 100 millimho/m, the measured
values for vertical dipoles decreases for an increase of actual sub-
surface conductivity, and the curves of the vertical dipole data
show more periodic electrical noise indicating its higher suscep-
tibility to this noise. These effects that result from the instrument
design and the nature of the electromagnetic fields are discussed
in a previous paper.' Similar visual analysis can be made for the
curves for the other instrument configurations. Comparisons be-
tween configurations also will give information about the noise.
200-
•i 100H
80-
NoriionulDlpoIci
20
Station Number
Figure 3
Example of EM34-3 10-m Field Data from the Pittman Transect.
Smooth Curves Are the Data after Digital Filtering.
From these curves, it is clear that noise can cause variations of
measured values of apparent conductivity of about 40 to 50%
from their mean values, thus making interpretation based on
them difficult without further processing and modeling. The next
step was to process these data to mitigate the noise. This analysis
involved Fourier analysis and digital filtering to eliminate the
periodic noise components. The results of this processing are
shown in Fig. 3 for the 10-m measurements along with the original
data.
Inverse Modeling
The data now are ready for interpretation by Inverse Modeling.
Inverse modeling is a computerized program that fits a model (in
this case, the one-dimensional model in Fig. 1) to the measured
data.' The basic operation of the inverse model is shown in Fig. 4.
For each station (i.e., for each vertical sounding) the mean value
and its standard deviation (explained below) for each of the 10
measurements are input into the program. The number of layers
(3 for the EMI), and an estimate of their thicknesses and conduc-
tivities are input as the starting values for the model. The inverse
model uses these starting values to calculate the apparent conduc-
tivities that would be measured at the 10 coil configurations used
Figure 4
Block Diagram of the Computer Inverse Model Used in thii Study
in the sounding. These calculated values ofMc then are compared
with the actual measured values og^a* in the least square sense;
the squared error
S.E.
(I)
is calculated where i is summed over the 10 coil configuration!.
The task of the inverse model is to make changes to the original
model parameters, i.e., the layer thicknesses and conductivities,
in such a way that the S.E. decreases. It continues this process
iteratively until the change in S.E. is below a user specified value,
then proceeds to the next station after the final model parameters
and the statistical information are written to a file.
At this point it should be mentioned that a previous study at-
tempted to simplify the inverse modeling technique9 by using a
linearized procedure suggested by the instrument manufacturer.
This procedure did not produce satisfactory results because of
conductivities that exceeded the low induction number approx-
imation/ therefore, an inverse model that does not depend on this
approximation must be used. Unfortunately, most cases of in-
terest seem to exceed the approximation.
Input to Inverse Model
The filtered data are input into the program in the form of
means and standard deviations of the apparent conductivities.
The means in this case are the averages over 40 m, 20 m each side
of the station, because isotropy is assumed over this range, and
the longest coil separation integrates over 40 m. The standard de-
viation can be considered to consist of two components, one from
electrical and geological noise and one from the actual change in
the subsurface structure (anisotropy) over the length of the
model. The noise component SL is calculated by taking the vari-
ance of the difference between the filtered data and the original
data over the 40-m range, i.e.,
where L is the number of stations on each side of the station,],
that are included in the calculation, and k is the coil configura-
tion. The anisotropy component S&, also calculated over the
40-m range, is defined as
134 SAMPLING & MONITORING
-------
= v
1-J-L
(3)
where S$ean is the mean value of apparent conductivity for the
jth station.
The sum of the two components Stetal is the standard deviation
that is necessary in the Inverse Model program to make the rows
of the matrices have equal variance.
After the means and standard deviations were calculated for
the Pittman Transect using the above procedure, and a 3-layer
model was estimated based on well data, inverse modeling was
done at 116 consecutive stations along the transect.
Although the objective of this groundwater contamination
study is to define the subsurface contamination, it is necessary to
calculate all layer parameters unless some are known. In the latter
case, they can be constrained to the known values. Since we want
to demonstrate the efficacy of the EMI for determining the sub-
surface model, we originally have required the program to
calculate all layer parameters.
Statistical Diagnostic Tools
Before the modeling results are analyzed, it is necessary to
briefly describe the principal statistical diagnostic tools. These
"internal" diagnostics provide a check on the procedure; they tell
how well the procedure is working. They do not necessarily tell if
the results correspond with the real world.
Squared Error
The squared error, defined above, is a measure of how well the
program was able to fit the model to the data. Usually, this error
can be made small by increasing the number of adjustments to the
parameter, i.e., the number of iterations that the program makes.
If it is not able to fit the data, it could mean excessive noise in the
data, an entry error or an inadequate number of layers in the
model. On the other hand, a good fit does not necessarily mean
that the model obtained is a true representation of the real world.
It is one piece of information that will aid the interpretation.
Percent Residual
The percent difference between measured and calculated values
of apparent conductivity for the ith coil configuration is
R. =
(4)
RJ gives specific information on the fit of the ith coil configura-
tion and can be used to determine if an instrument calibration
problem exists. For example, if the 40-m vertical dipole residuals
were consistently low or high, one might suspect that the instru-
ment calibration is incorrect; if the residuals for the longer coil
separations were large, one might suspect that the model is not be-
ing fit well at greater depths. Again, it is another piece of the
puzzle.
Parameter Standard Deviation
This quantity is a statistical parameter that is generated from
the least squares regression algorithm that fits the model to the
data. A mathematical expression for it is not helpful here since it
involves matrix algebra and a discussion of biased estimators. The
PSD is an internal diagnostic that gives the investigator a flag if
the program is not able to fit the parameter well. A high value of
PSD indicates that the parameter cannot be trusted because of
highly correlated measurements or parameters, layers that are too
thin or deep, etc. For example, if the model estimates a parameter
to have a value of 50 and a PSD of 3, the standard interpretation
would be that the true value lies between 44 and 56 with a 96%
certainty. The preferred interpretation here is to look at the
relative values of PSD and simply use high values as a flag that a
problem might exist for that parameter.
Parameter Correlation Matrix
The elements of this matrix show the correlation between any
two parameters. A high correlation (near plus or minus 1.0) be-
tween two parameters means that the probability is low that each
can be individually determined. The product or ratio sometimes
can be determined in these cases. A value near zero means that the
parameters are not correlated. A typical case is that for a deep
layer, only the product of thickness and conductivity can be well
defined since the surface measurements could be caused by a thick
layer of low conductivity or a thin layer of high conductivity. This
matrix usually is not used directly in the interpretation, but rather
as a check to see why some parameters are not well defined.
Reference for Validation:
Before we return to the case study, it is important to establish a
method of comparison with the real world. This is an "external"
check that is desired to evaluate the results of inverse modeling.
At this site, a comparison was made with a vertical cross-section
(Fig. 8) obtained from interpretation of borehole induction logs
taken by the manufacturer* with a Geonics EM39 unit. The EM39
measures the electrical conductivity in the borehole using the
same principle of electromagnetic induction that is used by the
surface instruments. The vertical resolution of this instrument is
high and does not depend on depth as in the case of the surface
units. The volume of earth measured by this logger is small,
meaning that local lateral variations (geological noise, in-
homogeneities, etc.) can strongly affect the measurements. The
interpretation in Fig. 8 was based on 15 vertical logs made at
200-ft intervals from station 36 to station 117 using a forward
model program supplied by the manufacturer. It should be
understood that, although the vertical resolution of the downhole
probe is high, the interpretation between stations is made assum-
ing a spatial continuity that is not shown by this technique.
INTERPRETATION
We now return to the case study to demonstrate the use of these
diagnostics. Because of space limitations, only a few steps of the
analysis will be given to illustrate the procedures.
20 40 60
(c)
Stitlon Number
Figure 5
Output from the First Runs of Inverse Modeling for the first 60 Stations.
Shown are: (a) Vadose Zone Conductivity, (b) Aquiclude
Conductivity, and (c) Water Table Elevation.
Fig. 5 shows the results of the initial runs for the vadose zone
and aquiclude conductivities and for the vadose zone thickness
for the first 60 stations. These examples were chosen to show
some of the features of the EMI and the data acquisition method.
Fig. 5a shows the vadose zone conductivity profile as a fairly
smooth varying function of distance along the transect. Further-
more, a comparison of this representation with Fig. 8 shows that
SAMPLING & MONITORING 135
-------
the relative values compare well, that is, both representations
show maxima in the region of station 40 to 50. A discrepancy in
absolute value is not surprising since the borehole measurements
are localized values, whereas the surface instruments average over
larger volumes of earth. In Fig. 5c, the results for the vadose zone
thickness also compare favorably with the measured values (from
monitoring wells) shown in Fig. 8 except in the region 40-50. This
problem can be understood by noting that the top layer conduc-
tivity is extremely high in that region. This has the effect of sharp-
ly limiting the depth of penetration of the EMI instruments,1 and
hence their sensitivity to resolving layers at depth. This effect also
can be seen in Fig. 3 as a strong anomaly in the 10-m vertical and
horizontal dipole raw data and is evidenced by an anomaly in the
aquiclude conductivity in Fig. 5b. The extremely high near-
surface conductivity, therefore, masks the deeper phenomena and
sets a limit for the EMI instruments. This is the limitation this
study targeted to examine.
We now turn to an analysis that exploits the statistical nature of
our procedure. The first step involves a visual inspection of the
parameter curves for values that depart radically from their
neighbors. Anomalous values are suspect because the station in-
terval (10 m) is small compared to the length of the maximum coil
separations (20 and 40 m) and compared to the range of spatial
correlation displayed by the field data. Considering this, we
suspect that no great change in layer parameters should take place
over 10 or 20 m, rather, that the change will be a smooth transi-
tion to higher or lower values. This statement is a consequence of
results borrowed from Geostatistical analysis of the data that
state that the values of a spatially correlated random variable will
vary smoothly within the range of correlation.'
Station 6 (Fig. 5), for example, shows a strong anomalous value
for the aquiclude conductivity (10 millimho/m). Referring to
Table 1, one sees that its Parameter Standard Deviation is very
large (4.10) compared to neighboring values (about 0.03). This in-
dicates that the program considers the reliability of that value to
be low. The problem in this case (and for station 36) was caused
by data entry error. A different type of problem was encountered
for stations 15-20 that exhibit an almost zero (
-------
An interesting outcome of the study, most easily seen from Fig.
8, is that the highest contamination values appear at the bottom
of the aquifer or in the clay aquiclude. Conductivity greater than
about 200 millimho/m is not typical of the clay itself.2 A possible
explanation is that, since the clay conductivity is considerably
greater than the contaminated aquifer conductivity, the clay has
absorbed and retained contamination over time. An even more
significant observation related to that result is that this effect is
not evident from the raw data or from water sample analysis (not
shown). The plume according to the water samples peaks at about
station 50, and the raw data (Fig. 6) show the highest apparent
conductivities between stations 40 and 50. We know from model-
ing, however, that the latter values result from a very high surface
layer conductivity. This example leads to the conclusion that in-
verse modeling can give significant information that is difficult or
impossible to interpret from profiling data or from water
samples.
12-
4-
280
10
350
X
450
100
730
370
\
SOO
210
350
20
100
276
21
220
250
25
270
225
40 80
Station Numbar
100
210
26
150
160
220. .210
120
Figure 7
Geo-electrical Cross-section of the Pittman Transect from Inverse
Modeling of Surface EMI Soundings. Conductivity Values Were
Averaged over 10 Stations for Presentation.
tween instrument and modeling limitations. Continuing the
analysis and interpretation in this manner will allow the investi-
gator to derive the maximum information from the geophysical
technique, and by combining this information with that derived
from other studies (geology, chemistry, hydrology, etc.), the pic-
ture can be improved further.
CONCLUSIONS
Several conclusions can be drawn from this study. First, the
EMI instrumentation has a limitation regarding the maximum
subsurface conductivity, i.e., high top layer conductivities effec-
tively act as a shunt to the induction of energy into the lower
layers. The limitation here occurred at a top layer conductivity of
about 400 millimho/m. As predicted by the manufacturer, data
from the vertical dipoles configurations for the EM34-3 are not
interpretable for layer conductivities over about 95 millimho/m
without correlating them with data from the horizontal dipole
configurations. This limitation, however, was compensated for in
the analysis by using the high data density combined with the
spatial correlation of the data. Next, the vertical dipole configura-
tions are much more sensitive to electrical noise than the horizon-
tal dipole configurations. These are convincing arguments for the
necessity of vertical soundings and subsequent inverse modeling
of the data.
Finally, a product of a consistent field-to-finish statistical ap-
proach is a set of diagnostic tools that enables the investigator to
analyze the interpretation at each step of the process. The EMI
technique used here, despite the limitations of the instruments,
was able to show the important features of subsurface contamina-
tion with this interpretation procedure.
DISCLAIMER
Although the information in this document has been funded
wholly by the U.S. EPA under cooperative agreement CR 812 189
to the Environmental Research Center, this paper does not
necessarily reflect the views of the Agency and no official en-
dorsement should be inferred.
E
$
1 ,-
|
|
o .
iu
•2-
WatarTabla
Aquiclude
1
Conductivity
(mllli-mho/matar)
I— 1 0-60
ES3 60- 100
S3 100- 200
m 200- 400
ES3 400- 600
HB *00- 800
mm 8oo-i3oo
120
Station Numbar
Figure 8
Geo-electrical Cross-section of the Pittman Transect from Borehole
Conductivity Logs. Water Table and Aquiclude Depths Are from
Direct (Physical) Measurement.
This brief analysis has shown that this method provides abun-
dant information to guide the analysis and to differentiate be-
REFERENCES
1. LaBrecque, D.J. and Weber, D.D., "Numerical Modeling of Electri-
cal Geophysical Data over Contaminated Plumes," Proc. of the Na-
tional Water Well Association Conference on Surface and Borehole
Geophysical Methods, San Antonio, TX, 1984.
2. McNeill, J.D. and Bosnar, M., Technical Note TN-22 "Surface and
Borehole Electromagnetic Ground water Contamination Surveys: Pitt-
man Lateral Transect, Nevada," 1986.
3. Weber, D.D. and Flatman, G.T., "Statistical Approach to Ground-
water Contamination Mapping with Electromagnetic Induction: A
Case Study," Proc. of the National Water Well Association Confer-
ence on Surface and Borehole Geophysical Methods and Ground-
water Instrumentation, Denver, CO, 1986.
4. Weber, D.D., Flatman, G.T. and Koebke, T.H., "Subsurface Con-
tamination Mapping from EMI Soundings," Proc. of the HAZTECH
International Conference and Exhibition, Denver, CO, 1986.
5. Weber, D.D. and Scholl, J.F., "Spatial Mapping of Conductive
Groundwater Contamination with Electromagnetic Induction,"
Ground Water Monitoring Review, 4, Fall 1984.
6. McNeill, J.D., Technical Note TN-6 Electromagnetic Terrain Con-
ductivity Measurement at Low Induction Numbers, Oct. 1980.
7. Flatman, G.T. and Yfantis, A.A., "Geostatistical Strategy for Soil
Sampling: The Survey and the Census," Environmental Monitoring
and Asssessment, 4, 1984, 335-349.
SAMPLING & MONITORING 137
-------
Processes Affecting the Interpretation
of Trichloroethylene Data From
Soil Gas Analysis
Elsa V- Krauss
John G. Oster
Kurt O. Thomsen, Ph.D., P.G.
P.R.C. Engineering, Inc.
Chicago, Illinois
ABSTRACT
The use of soil gas analysis data in remedial investigations has
increased in recent years. These data have been used to design
monitoring systems, to identify areas having soil and/or ground-
water contamination and to define the extent of the groundwater
contamination plumes. An assumption implicit in most of the soil
gas analysis studies is that the soil gas values measured at a loca-
tion are representative of the chemical contamination at that
location. Quality assurance experiments conducted during a recent
soil gas analysis survey at a waste disposal site have shown that
this assumption may be erroneous.
One set of experiments addressed the fluctuation of trichloro-
ethylene (TCE) in soil gas as a function of lime. Preliminary results
suggested that TCE concentrations in soil gas increased significantly
during the morning and early afternoon and decreased in the late
afternoon and evening. This increase correlates with changes in
temperature during the day. Diurnal experiments were conducted
to verify this phenomenon by taking hourly readings in areas having
low, medium and large soil gas TCE responses. Significant varia-
tion in the TCE response occurred in the hourly analyses, but the
24-h analyses showed no variation.
Another set of experiments was conducted to determine whether
soil gas values were representative of soil and/or groundwater con-
tamination. In situ soil gas analyses were conducted in bore holes
as they were being advanced. Soil and groundwater samples were
collected for analysis. The resulting data indicated that, in a signifi-
cant number of cases, the soil gas TCE values did not reflect soil
or groundwater TCE values. This finding suggests that the flow
of soil gas through the unsaturated zone may have an important
horizontal as well as a vertical component. This horizontal com-
ponent may be related to the documented difference in horizontal
and vertical permeabilities known to exist in most soil strata.
INTRODUCTION
The objectives of this study were: (1) to determine whether the
trichloroethylene (TCE) concentration in soil gas is a function of
time and temperature and (2) to determine whether soil gas values
are representative of soil and groundwater contamination.
A relatively new method used to estimate the direction, extent
and chemical composition of groundwater involves measuring the
concentrations of diffusing chemicals in soil gas near the surface.
With the past few years, soil gas measurements have been used
more extensively to define subsurface contamination plumes, par-
ticularly for volatile organic compounds. However, the ability of
soil gas sampling to detect and delineate groundwater contamina-
tion plumes depends on specific properties of the compounds (such
as vapor pressure and solubility) as well as characteristics of the
site, i.e., soil moisture content, porosity, permeability and grain-
size distribution).
Soil gas sampling applications are not restricted to detecting and
delineating subsurface contamination during the site investigation;
soil sampling can be utilized in the cleanup operation.
This paper provides a comprehensive site-specific analysis of the
applicability, precision and limitations of a soil gas sampling survey
conducted at a waste disposal site.
SITE CHARACTERISTICS
The site investigated is a waste disposal area situated on the upper
portion of a peninsula formed by a reverse "s" meander of a river.
A manufacturing facility is located on the lower part of the penin-
sula (Figure 1).
Figure I
Site Plot Plan for Soil Gas Analysis Investigation
138 SAMPLING & MONITORING
-------
The general site stratigraphy has five major hydrogeologic units.
The uppermost unit is an unconfined glacial outwash aquifer which
communicates with the river. Within this unit in the western por-
tion of the site is a lacustrine aquiclude. Remnants of this aquiclude
were also found in the eastern portion of the site. Underlying this
upper outwash aquifer is a substantial glacial till aquiclude followed
in order by another glacial outwash aquifer, a glacial till aquiclude
and a glacial outwash aquifer which was encountered in one bore
hole at an approximate depth of 150 ft below grade.
The major hydrogeologic units encountered in the central portion
of the site where most of the disposal activities took place were
the upper outwash aquifer and the underlying upper till unit. Within
the upper outwash aquifer are lenses of various combinations of
fine materials which act as aquitards or aquicludes. These lenses
form the aquiclude/aquitard units and are found at many levels
and varying areal extents throughout the upper outwash aquifer.
The majority of these units seem to be grouped at elevations of
805 and 790 ft (grade elevations range from 811 ft, which is the
river elevation, to 835 ft). The two identified aquiclude/aquitard
layers exhibit variable hydrological characteristics. This variabili-
ty is reflected by the fact that at some locations the 805 layer ex-
ists, but not the 790 layer, and vice versa. At several locations,
the 805 and 790 layers are one unit, while at other locations neither
exists. In addition, some locations have layers at other levels within
the upper outwash aquifer which do not correlate with either the
805 or the 790 layers.
Figure 2 shows the area where the major disposal activities took
place. Three paint sludge pits were located in the area of monitor-
ing well MW-2. A cache of drums was buried just west of MW-2;
drums also were placed in a ravine located in the western portion
of the site north of MW-3. The central portion of the site, between
MW-1 and MW-2, was the location of numerous batch spills and
solid wastes disposal activities.
Figure 2
Location of Disposal Areas
SAMPLING METHODOLOGIES
Soil Gas Sampling
The soil gas sampling technique consisted of driving a metal
hollow probe to a desired depth in the soil, extracting soil gas with
an air sampling pump and collecting the gas in a glass syringe or
glass sampling bulb.
The stainless steel sampling probe is 5 ft long, with a Vi-m. outer
diameter (OD) and a 0.2-in. inner diameter (ID)(Figure 3). The
probe is closed at the tip and perforated above the tip to permit
the soil gas entry. A drive plate permits the probe to be hand driven
up to 3 ft into the soil. The aboveground end of the probe then
is fitted with a 2-ft section which contains a sampling port with
a silicone septum. Soil gas is extracted via an air sampling pump.
The probe was evacuated at a rate of 1.5 1/min. A sample was
Figure 3
Soil Gas Sampling Apparatus
drawn from the probe with a 10 cm3 glass syringe equipped with
Mininert valves or a 250 ml glass sampling bulb. The soil gas sample
was introduced directly into a portable gas chromatograph (GC),
HNU Model 301 at the site.
Several precautions were taken to assure the accuracy of the soil
gas measurements.
• Prior to sampling, syringes and bulbs were purged with nitrogen
and checked for contamination by injecting the nitrogen into
the GC.
• Probes were cleaned with tap water followed by a methanol or
acetone rinse and a final rinse with distilled/deionized water.
The probes were then dried with a propane torch. After cleaning,
atmospheric air was drawn and injected into the GC to ascer-
tain the completeness of the cleaning process.
• The silicon septum on the probe was changed after every 10
samples.
• The GC was continually calibrated with chemical standards
prepared from 0.1 mg/ml trichloroethylene (TCE), in methanol
prepared by Chem-Service, Inc. of Westchester, Pennsylvania,
and 10 ppm TCE in nitrogen from Alltech Associates, Deerfield,
Illinois.
Water Sampling
Water samples were taken with a 1/2-in. O.D. PVC bailer. The
bailer was lowered into the well using a nylon coated rope. Three
volumes of water were evacuated prior to sampling. The first two
bails collected were discarded to acclimate the bailer to the well
water. The third bail was used to rinse the sample containers. When
the sample was transferred from the bailer to the appropriate sam-
ple container, care was taken not to agitate the sample, thus
avoiding the loss of volatile constituents by aeration. Once the wells
were sampled, the sample containers were stored on ice.
To prevent cross contamination between wells, all PVC bailers
SAMPLING & MONITORING
139
-------
and ropes were decontaminated with distilled water, followed by
an acetone rinse and distilled water rinse. Bailers and ropes then
were allowed to air dry. Water samples were sent to a laboratory
for chemical analysis.
Soil Sampling
Boring locations were selected to evaluate the stratigraphy of
the materials underlying the site, to identify directions of ground-
water movement and to determine the presence and areal distribu-
tion of two potentially semi-confining layers.
Soil samples were obtained from the surface and at depth inter-
vals of approximately 5 ft with a 2-in. ID split-spoon sampler.
Representative portions from each split-spoon sampler were
preserved in round, screw-top, airtight-glass jars for physical
analysis. Additional portions were collected from surface grade
until groundwater was encountered; these samples were preserved
in glass jars placed on ice. Each jar was labeled with a boring
number, sample number, the depth at which the sample was ob-
tained and the blow count values for each S-in. interval. To pre-
vent cross-contamination between sampling intervals, the split-
spoon sampler was washed with tap water, rinsed with acetone and
then with distilled water and allowed to air dry. Soil samples were
sent to a laboratory for analysis.
ANALYTICAL METHOD
All soil gas samples and head space samples were analyzed at
the site using an HNU 301 GC equipped with a dual flame ioniza-
tion detector (FID) and a photoionization detector (PID). The col-
umn used in this study was 6-ft by 1/8-in. stainless steel packed
with 0.1% AT-1000 on 80/100 mesh Graphpac GC from Alltech
Associates, Deer field, Illinois. UHP nitrogen was used as the car-
rier gas (flow rate 25 cmVmin). The oven was operated isother-
mally at 1SO°C while the injector/detector temperature was main-
tained at 200 °C. Soil gas samples were introduced into the GC
directly from the syringe used to collect the sample or the syringe
used to extract the sample from the glass bulb.
Soil and water samples were analyzed in the laboratory using
a Hewlett Packard 5880 GC equipped with are Electron Capture
detector.
DIURNAL SOIL GAS ANALYSIS
The objective of the first set of experiments was to determine
whether TCE concentration in soil gas is a function of time and
temperature.
During a survey in the fall of 1985, a test was performed to check
the variability of TCE concentration as a function of time. The
data indicated that the TCE response increased as the temperature
increased during the day and decreased as temperatures decreased
in late afternoon and evening (Figure 4).
To verify this phenomenon, a 24-hr soil gas analysis was per-
formed during late spring in 1986. Three locations containing low,
medium and high TCE responses were chosen near wells CNl, AS1
and MW-17. Sample volumes of 5 to 10 cm3 were collected with
a 10 cm1 gas-tight syringe equipped with Mininert valves. A set
of syringes was dedicated to each location to prevent cross-
contamination. Replicate samples were taken at each location. Tune
and temperature were monitored closely.
The results of this test showed significant variability between
samples throughout the daj. However, the diurnal analysis showed
no change. The relationship of TCE peak heights and time is shown
in Figure 5 for each location.
O CHI
Figure 5
Log In Situ Soil Gas TCE Peak Height as a Function of Time
Reproducibility
A statistical analysis of the reproducibility of this test
demonstrated that for the high TCE responses at well CNl, the
reproducibility of this method was 3 to 8%; for the low to
medium TCE responses at AS) and MW-17, the reproducibility
was 10 to 35%, which is a measure of both human/instrument
performance and the effects of the volume of soil gas pumped.
Replication
Throughout the study it was noticed that the results of con-
secutive samples demonstrated an increased TCE response after
evacuating the probe. This prompted an analysis of seven con-
secutive soil gas samples at one of the locations used in a previous
survey. A plot of this relationship (Figure 6) shows that the rela-
uruuri KUKIU
Figure 4
CNl Soil Gas TCE Peak Height as a Function of Time
Figure 6
Soil Gas TCE Peak Height as a Function of Replicate Number
140 SAMPLING & MONITORING
-------
tionship is linear. It suggests that there might be an optimal amount
of soil gas which needs to be evacuated to obtain a representative
sample. Review of similar data having two to three replicates seems
to indicate that a linear relationship may exist at other locations;
however, these relationships will vary from location to location.
Effects of Soil Moisture
During the course of this study, it was observed that the soil
moisture content greatly increase the soil gas TCE response. The
initial soil gas analysis survey was conducted shortly before a period
of heavy rainfall. Resampling several points on the original survey
grid after an extended rainy period resulted in significant increases
in the TCE soil gas responses over those recorded during the
original survey.
SOIL GAS PROFILING
The objective of the second set of experiments was to deter-
mine whether soil gas values are representative of soil and ground-
water contamination. Surveys profiling soil gas responses as a
function of depth can yield information as to which medium is
contaminated; that is, whether the contamination is in the soils
or in groundwater(l). Decreases in soil gas responses with depth
indicate soils contamination; increases indicated groundwater
contamination.
As part of this study, profiling was conducted at several loca-
tions. In situ soil gas TCE responses were taken and soil was
sampled and subjected to head space analysis. Splits of the soil
samples were sent to the laboratory, where the TCE was extracted.
After the bore hole was completed and the wells were installed,
the groundwater was sampled and analyzed for TCE.
Techniques
Soils were sampled at the surface and at 5-ft intervals until the
water table was encountered. At the surface, an in situ soil gas
sample was taken as described above. A 2-ft split-spoon sampler
was driven into the soil and the resulting sample was split into three
fractions. One fraction was dedicated to head space analysis, one
fraction went to laboratory TCE extraction, and the final frac-
tion went to the soils laboratory for grain-size analysis. After the
soil fractions were obtained, the auger was advanced 5 ft to the
next sampling depth.
One variation in the soil sampling technique described above was
used during profiling. This consisted of using a 1-in. electrical con-
duit. Before driving the soil gas probe, it was inserted into the con-
duit, thereby limiting probe flexing.
Twenty 6-g samples of soil were placed in six 40-ml vials having
caps fitted with septa. Three vials were sent to the laboratory for
TCE extraction; the remaining three were used for on-site TCE
head space analysis. Samples for head space analysis were prepared
by shaking the sample vials vigorously for 2 min, allowing them
to sit for 5 min and extracting a head space sample using a syringe.
RESULTS
Two methods were used to determine the soil gas TCE response
during profiling: (1) in situ measurement of TCE in the soil gas
and (2) head space analysis of an extracted soil sample. Figure 7
shows a plot of the head space TCE responses as a function of
the in situ TCE responses. One would expect a correlation to exist
between the head space TCE response and the in situ TCE response
measured at the same location and depth. However, Figure 7 shows
that this relationship does not exist. This result probably can be
attributed to the disturbance of the soil sample during the sampling
and sample preparation process.
In addition, a review of the in situ/head space data revealed no
pattern where one method of soil gas measurement yielded higher
TCE responses than the other. In some cases the in situ TCE
responses were larger than the head space TCE responses, and vice
versa. It was thought that grain size could be a contributing factor.
With extracted soil samples, soil gas trapped by finer material could
yield higher head space responses than the in situ responses. With
a
i
I
I
I
j
§
!
•
1
a
7.0-
(.0 -
S.O-
4.0-
J.O -
1.0-
1.0 -
a
a
a a a
a a a
a
aaD
DO ° o
o
Baa
0 0
3 0.0 1.0 2.0 3.0 4.0
LOO nnrru SOIL
-------
LO i.O 10.0 IU 14.0
PIICIIIT mat Ǥoo mil)
If* 11.0 BO.O
Figure 9
Log Head Space TCE Peak Height as a Function of Percent Fines
situ soil gas TCE response is greater than predicted, indicating that
soil gas TCE is being transported to the sampling location from
another location. This suggests that the flow of soil gas through
the unsaturated zone may have an important horizontal as well
as a vertical component. This horizontal component may be related
to documented differences in horizontal and vertical permeabilities
known to exist in most soil strata.
Table 1
Summary of TCE Data as Function of Depth
Locttioa
1
B
C
C
C
C
CNI
MINI
MINI
MINI
MISI
MISI
tjO
IOJ
I4J
1.0
U
1JI
»J>
1.0
10
LO| lBlll«
Soil Omt TCE
Pe»k H>l|kl
I.JI
l.tt
1.10
2.11
2J4
1.75
2JI
2.71
IJU
1.71
2J7
in
Soil TCE
(•I/KI)
b
b
b
b
b
b
5
<0.05
<0j05
BUB. it il. (I9IJ) (2).
' No TCE Mil •euireMBli kvBllible.
• Tkl rllfj of ib< pr«dlcud Mil |*i TCE pnk b| Ikll
B^BlBi«a TCE valMf were I Bi|/k| kad I at/L for ull kBd irouBdwkttf, rnpccllvcly, kfld
•"!••• ral>« >er< 50 mt/ki tad 50 »|/U inpoellnly.
CONCLUSIONS
The results of the experiment suggest that the interpretation of
soil gas data may be more complicated than previously thought.
On the other hand, the results suggest that more information may
be obtained from soil gas collection and analysis activities.
The following observations were made during the course of this
study:
• During diurnal testing, hourly soil gas TCE sampling showed
significant variation between samples, but the diurnal trend
exhibited no change over the 24-hr sampling period. The results
were the same for tests conducted at three locations having low,
medium and high soil gas TCE responses.
• Replicate sampling at surface soil gas sampling locations showed
a marked increase in TCE response as more replicate samples
were taken. This relationship seems to be linear and suggests
that there may be an optimum volume of soil gas which should
be evacuated before sampling.
• The presence of soil moisture seemed to enhance the soil gas TCE
response.
• No relationships existed between head space measurements of
TCE in soil samples taken from the in situ sampling locations
and the in situ measurements of TCE. This probably is due to
the disturbance of soil structure during sampling.
• No relationship could be established between head space TCE
responses in the soil gas and the amount of Tines in the soils.
This also was true of the in situ TCE responses as a function
of the percent fines. Again, this may be due to disturbance of
the soil sample while conducting a grain size analysis. This
finding suggests that the in situ soil moisture content, permea-
bility, porosity and density are key parameters in determining
the volume of soil gas which can exist in a given soil pore space.
• Comparison of in situ soil gas TCE responses with TCE soil and
groundwater concentrations showed significant differences
between the amount of TCE expected in the soil gas and the
amount actually measured. Cases were observed where the soil
gas TCE response was greater than expected and less than
expected. These results suggest that a horizontal component of
soil gas movement through soil pore spaces may be significant,
particularly since it has been documented that most soil strata
have greater horizontal permeability than vertical permeability.
The experiements conducted and the observations made during
the course of this study were auxiliary to the soil gas analysis survey
conducted at the waste disposal site and are preliminary in nature.
More work is required to verify these findings and learn more about
the nature of the movement of soil gas in soil pore spaces. The
results of this study are helpful in planning future soil gas analysis
surveys and suggest that more information may be available to the
researcher through the use of this technique.
REFERENCES
1. Marrin, D. L. and G. M. Thompson, "Remote Detection of Volatile
Organic Contaminants in Ground Water via Shallow Soil Gas
Sampling." Tracer Research Corporation, Tucson, AZ. 172-186.
2. Lyman, W. J. "Solubility in Water and Soil," in W. J. Lymanrt
al. (eds.) Handbook of Chemical Property Estimation Methods.
McGraw-Hill Co., New York, N.Y. 1982.
142 SAMPLING & MONITORING
-------
Field Quality Assurance: A System for
Plan Review, Tracking and Activity Audit
Kathleen G. Shimmin
Harry E. Demarest
Peter L. Rubenstein
U.S. Environmental Protection Agency
San Francisco, California
ABSTRACT
The purpose of this study was to develop a process for plan-
ning and executing field sample collection undertaken in support
of Superfund investigations in U.S. EPA Region IX. Procedures
are described for preparing Sample Plans which detail study ob-
jectives, rationale for sampling, analytical resource requirements
and field methodology, incorporating Agency protocols. The
plans also serve as a basis for audits of field activity. Criteria have
been developed to review and evaluate field work quality.
The procedures have evolved over a 3-year period, during
which approximately 150 site-specific Sample Plans have been re-
viewed and over 15 field audits have been conducted in Cali-
fornia, Arizona and Nevada. Participants in the system include
contractors, cooperating state agencies and the U.S. EPA. Im-
portant elements of the process are training, communication,
automated tracking systems, consistent review and followup to
correct deficiencies.
Details of the system will be discussed, and field examples of
the process will be shown. The findings demonstrate the impor-
tance of management overview and audit in order to achieve val-
id data and effective resource utilization.
INTRODUCTION
Nationwide, the Superfund program has been expanding rapid-
ly and this pace will increase with the anticipated reauthoriza-
tion. In U.S. EPA Region IX, many organizational units and con-
tractors participate in the process of site assessment and cleanup.
One unit (the Superfund Programs Branch) bears ultimate re-
sponsibility for assuring that a comprehensive schedule is estab-
lished to carry a given site from the point of discovery to clean-
up. Field operations and associated contractor support are the
responsibility of the Field Operations Branch. Since a number of
activities in several organizational units may occur simultaneous-
ly, it is essential to coordinate and track the phases so that funds
will be spent effectively, milestones will mesh and contamina-
tion threatening the public health and environment will be miti-
gated expeditiously.
The process of site assessment involves two major technical
arenas: field surveys (including monitoring and sample collec-
tion) and laboratory analyses. All activities must be planned in
advance, staged and the results interpreted to accurately assess
contamination characterization at a given geographic location.
In the laboratory phase of the assessment, the analytical pro-
tocol and the data review/validation process follow well-estab-
lished and accepted methods. Generally, historical compilations
of laboratory results using the standard methodologies exist so
that specific findings may be contrasted with theoretical expec-
tations. With many individual laboratories and researchers using
standard methodology, the statistical evaluation of outcomes can
be based on a relatively large population sample.
These perspectives and data bases are not available for most of
the field work associated with hazardous waste sites. Procedures
for the planning and execution of field work have not been stand-
ardized to any substantial extent. The purpose of this study was
to develop an effective, orderly procedure to plan and audit field
work, with a goal of reducing the opportunity for error. This
paper is based upon findings gathered from reviews of more than
150 plans and audits of approximately 10% of these plans.
Typically, there are limited and specific applications for field
studies undertaken in support of Superfund:
• Regulatory activity—to establish U.S. EPA authority and to
permit U.S. EPA involvement
• Enforcement evidence gathering—to demonstrate a violation
of the law
• Investigation—to gather information on the type, extent and
dispersion pattern of contamination
• Remedial project decision-making—this is the most demand-
ing use of data
Usually, this last application has the greatest number of asso-
ciated consequences—both economic and social. Design and im-
plementation of multimillion-dollar remedial programs are based
upon analytical findings. These solutions are expensive and the
prospect of being wrong is untenable for the welfare of the
affected population as well as for budgetary reasons.
For any of these applications, the attributes of the high quality
data being sought include:
• Validity—the concentrations and identities of the pollutants
fall within acceptable confidence limits, or if they do not, the
actual confidence limits can be stated
• Accuracy—the assessment of contamination closely reflects the
situation originally being investigated
• Defensibility—the evidence must be able to stand up in court,
i.e., maintain credibility under intense scrutiny by experts in an
adversarial setting
• Reproducibility—the results must be achievable by another re-
searcher using comparable equipment and methodologies
Seven or 8 years ago, there was mostly art in the application of
state-of-the-art hazardous waste sampling. Contaminants were
measured usually in the ppm range. Today, however, it is rou-
tine to measure contaminants in the ppb and ppt ranges of con-
centration. With this increased sensitivity in analytical quantifi-
cation limits has come a parallel need for corresponding sensitiv-
ity in the execution of the field work.
SAMPLING & MONITORING 143
-------
SAMPLE PLAN
The device developed by the Toxics and Waste Management
Division. U.S. EPA Region IX, to induce precision and accuracy
in hazardous waste field work planning is the Sample Plan.
Sample Plans are required of:
• All U.S. EPA sampling done in support of hazardous waste
programs
• All contractors doing similar work for U.S. EPA Region IX
• All cooperating state agencies
• All potentially responsible parties doing field work under a
Consent Agreement or other enforcement arrangement with
the U.S. EPA
Sample Plans serve dual purposes. They are used for:
• Justification for expenditure of laboratory resources—the U.S.
EPA Region IX (CA, AZ, NV, and HI) spent $1.4 million last
year in hazardous chemical waste analyses alone; the cost per
sample for organic hazardous substances has averaged over
$1.000.
• Field quality assurance—the Sample Plan document is used by
the field team as a blueprint of the field work (this plan may be
supplemented by a specific compendium of standard operating
procedures); it is used by the field auditors as a description of
what should take place during the field work.
The Sample Plan contains the following elements:
• Background information (usually the Preliminary Assessment)
• Objective of sampling effort
• Rationale for sample locations, number of samples and analyti-
cal parameters
• Maps
• Analyses to be performed
• Methods and procedures
Sample collection techniques
Equipment decontamination
- Disposal of contaminated materials
- Sample containers
Sample preservation
Sample packaging and shipment
Sample documentation
- Quality assurance samples
• Site Safety Plan
The plan usually contains a bibliography of pertinent standard
operating procedures. If the Sample Plan references another
document such as a quality assurance project plan or a special
analytical methodology, it should be included for ease of review.
Once the Sample Plan has been written, it is reviewed by a
qualified organizational unit separate from the Plan's author.
The review focuses on the Plan's logic flow from the opening
premises to the execution. The reviewer refers repeatedly to the
Plan's objectives, asking whether the hypotheses will be con-
firmed and whether the planned work will achieve the objectives.
Field work does not commence until the Sample Plan adequately
ensures that the field work to be undertaken will achieve the de-
sired objective.
Training is an essential element in the process. Formal train-
ing sessions are conducted by the U.S. EPA whenever there are
new teams coming into the system (these may be new contractors
or new state agencies). As a followup to the training, the U.S.
EPA schedules a field audit when the newly-trained team com-
mences field work for the first time after the training session.
This field audit has proven to be a cost-effective expenditure of
resources; it is much easier to work with the team, showing them
how to perform the work correctly at the beginning, than it is to
reassess the work after the fact and attempt compensations.
It is prudent to avoid setting up a system which has minimal
planning and focuses on resampling as a routine occurrence. The
cost of laboratory analyses for hazardous substances is too high.
Even more costly is the potential need to redeploy specialized
sampling equipment (such as drill rigs), special on-site monitor-
ing equipment and mobile laboratories.
The logistics of planning and staging field operations require
specialized tracking systems to assure that all the elements of the
project mesh. Currently, the U.S. EPA Region IX administra-
tive system is comprised of several separate organizational uniti
including contractors, and there are a large number of projects in
the system. Sample Plan reviews at times are complicated, with
several iterations of a plan going back and forth from reviewer to
author.
Once the field work is in progress for a given project, several
laboratories may be involved in sample analyses. To maintain
project momentum, successful completion of each step must be
tracked to enable all critical efforts to be accomplished. Comput-
erized tracking has proven to be the most versatile method. In-
herent in the concept of tracking is the need for periodic review of
progress and deliberate action to correct any problems in the com-
plex system.
Fig. 1 shows a diagram of the flow of a sampling event from
the initial determination by the project officer that a sampling
study is necessary with certain data objectives through to the pro-
duction of validated data. Decision points are shown. Review
must be timely so that overall project decisions and deadlines can
be achieved.
(1)
Project Requires Sample Collection
Data objectives determined
for Study (Project Officer)
Sample Plan Written
( Team A )
Sample Plan Reviewed
( Team B )
(3)
(4)
(5)
(6)
(7)
(B)
Laboratory Analyses &
Field Sampling Scheduled
I
Field Sampling
^
t
Samples to Laboratory
for Analyses
>
Data to Reviewers for
Data Validation
^
Validated Data to
Project Officer
Do»I field
•etuvv*
AT. nlMllwi <>»U
.ulfict.nl to Mhl«»
siudj obj«u«> *
_,
Figure 1
Sampling Event Diagram: Planning, Review, Execution and
Decision Points
144 SAMPLING & MONITORING
-------
Observations made during the performance of field work prove
that without a blueprint for the field work actually present on-
site, the work will proceed with shortcuts and other modifications
rendering the approved Sample Plan meaningless as a description
of what actually occurred in the field. This can cause errors in in-
terpretation when the results of analyses are provided. It further
has the potential to cause misdirection of resources to correct site
problems (i.e., money may be spent erroneously and the real
problems may persist uncorrected). However, field judgment is
essential to determine whether necessary modifications still
achieve study objectives.
FIELD AUDIT
The field audit process is outlined in Table 1. Checklists are
developed, specific to each sampling episode, and based upon the
investigation's Sample Plan.
Table 1
The Sampling Field Audit Process
I. Review and evaluate Sample Plan for completeness and adequacy.
A. Sampling objectives.
B. Rationale for sample locations, number of samples, and
analytical parameters.
i;. Methods t procedures.
1. Sample collection.
2. Equipment decontamination.
3. Sample containers.
4. Sample preservation.
5. Sample shipment.
6. Sample documentation.
7. Quality Assurance/Quality Control (OA/OC) samples.
ZI. Develop audit checklists based on Sample Plan.
A. Checklist for sampling at each sampling point.
B. Checklist for overview of the sampling event.
111. Conduct audit.
A. Field work
1. Document all field work with checklists, notes and
photographs.
2. Audit complete sampling process at one or more sample
points (more • better).
B. Interview samplers (after field work is completed).
1. Review overall sampling process.
2. Discuss problems so changes can be initiated.
3. Copy complete sampling field notes for the entire
sampling event.
4. Copy complete sampling field notes for prior sampling
event or events (Check for consistency of field work
over time).
IV. Review and evaluate field work for completeness and adequacy.
A. Hill the sampling event meet the Sample Plan objectives?
B. Are the sampling procedures adequate (professional judgment)?
C. Will the sampling procedures bias the data in a positive
or negative direction?
v. Compare the actual sampling event to the Sample Plan.
A. Has the Sample Plan followed?
B. Are dlscrepencies significant?
VI. Hrite the report.
A. Sample Plan review.
B. Field work review.
C. Comparison of field work with Sample Plan.
D. Validity statement as to usability of data generated by this
sampling effort as a result of procedures used in the field.
Table 2 is a typical checklist for overview of a groundwater
monitoring well sampling event. The checklist is tailored to pro-
vide a summary of the points for scrutiny. It should be noted that
for east of field operation, the details are compressed onto a
single sheet printed on both sides. The observation points are
arranged so that they follow the flow of the sampling effort as
described in the Sample Plan.
Table 3 shows a Summary of the Field Audit Findings during
a groundwater sample audit. A copy of this summary is given to
the field team after the exit interview by the auditor. The benefit
of providing immediate feedback is that problems may be cor-
rected promptly.
Table 2
Sample Audit Checklist
Typical Sample Audit Checklist (Ground water Monitoring Well)
(One Per Sample Location)
Date Purged:
Samplers:
Date Audited:
Date Sampled!
1} Was the well locked?
2) Is the well vented?
Is the well clearly labeled?
3)
4) Does the integrity of the surface seal appear adequate?
(Y/N)
(Y/N)
(Y/N) .
(Y/N)
5)
Was Depth-to-Water (DH) measured prior to the Initiation of purging? (Y/N)
Hhat was the increment of measure?
What device was used to measure DW?
Was the sounding equipment decontaminated after use?
What equipment was used to purge the well?
(Y/N)
7} Where in the water column was the intake Cor the purge system placed?
At the well screen (top middle bottom) Just below the surface
Other
8) Was the purging equipment decontaminated prior to purging?
(Y/N) .
Hew was the purging equipment decontaminated?
9) Was the Purge Volume calculated prior to purging?
10) Was the Purge Volume measured during the purging?
How?
(Y/N)
(Y/N)
11) Was a Discharge Rate measured during the purging?
How?
(Y/N)
13) What volume of water was evacuated?
14) How many Casing \blumes?
15) What was the purge schedule?
16} How was the purged water disposed of? _
17) What was the time period between the purge and saiplirg at this well?
18) Was Depth-to-Water (DW) measured just prior to sampling?
What was the increment of measure?
What device was used to measure DW?
(Y/N)_
Was the sounding equipment decontaminated after use? (Y/N)
FIELD JUDGMENT
The Sample Plan is not an inflexible document. There is no
method for authors of the plan to predict with unerring certainty
all the real field conditions. It is essential that the goals and objec-
tives of the investigation be stated clearly so that samplers may
have the leeway to substitute technologies and decisions which do
not adversely affect the overall objectives.
The Sample Plan is neither a substitute for field judgment,
nor a blueprint for auditor judgment. In fact, the Sample Plan
enhances both judgment and audit, because field personnel can
continually refer to the stated objective and question whether the
activity as described will achieve the desired objective. If the
answer is "no," then the effort must be modified, and both audi-
tor and sampling team must perceive the adequacy of the modifi-
cation to achieve the objectives.
TYPICAL FIELD DECISIONS
These field situations are given to illustrate the types of decis-
SAMPLING & MONITORING 145
-------
Table 3
Summary of Field Audit Findings During a Groundwaler Sample Audit
SMPLE AUDIT (Ground Water Monitoring Hellll OVERVIW
AudUort
Date Audited!
Facility Repei
I) When »«» the purge eaquence eatabllehed?_
2} Ho **a» the purge sequence eatabllahed? _
3) When are Depth-to-Mter iMiurexnu takan?_
41 AT* Depth-to-Bottcai weaaurennta taken?
5) Htv frequently?
ct/m
«) Ii the 'acundar' calibrated prior to each Maaurlng event?
7) Pro» utxn In UK »ater colian la the eaaple oollected?_
B) »»wt la the aource of UN eaaple oontalnera? _
» U UK Q/C incantation on the ea*>la containers available? If/Hi
10) tt»t Inforaatlan la kept In Held log bocks?
11) Are Chaln-ot-Cuatcdy recorde kept tor each eaqila? (I/M)
12) Ac* Chaln-of-Custody aesla placed on Men saiBple container? (l/M)
13) Does a Saaple Analysis Bequest sheet tcocnpuv *^h u^>l*7 (I/M)
14) Ar« dupllctu uvln ooll«ct«J7 Of/Ml
Ho* frvquvntly?
How ac« th« duplicate M^>1« point* M
IS) Are tr«v«l blanke collected?
Hc» trequently?
(r/N)
) Are equipaent rtneete/eethode blenke oollecteo7
IT) Are field blinke collected?
Ha. traquenUy?
(I/M)
16) teut U the eource at «eter lor the tjl«n» >Mplee?_
neld Hendling
19) Panaetec I/Type of Container and Preeeryetton
tani
KM
TCK
TOC
Cxtracublee
Anlone fc Cet
HeuU
RAD
ColKora
Cyanide
Cr».
Suit idee
Nitratee
20) Ho> Ireguently an Uie lenplei ehlppM?
211 Milch laboratorlea are being uMd tor thla wnpllng event?
ADOITICNU. OCHMEKTSl
ions which might be made during a sampling event. Sample team
members as well as auditors must be experienced enough to judge
146 SAMPLING & MONITORING
whether the field situation encountered warrants a deviation from
the Sample Plan to achieve the objectives of the study. The aud-
itors must also be able to evaluate whether any perceived devia-
tions from the approved Plan procedures actually constitute sig-
nificant variation.
Example I
The purpose of a recent investigation was to collect dry sedi-
ment samples for the analysis of pesticides. The sample location
was a dried pond in a low spot on the property. In the Sample
Plan, the procedure specified sampling the upper 2 in. of sedi-
ment. However, in the field, the sediments in the dried pond wen
unexpectedly clay material with cracks 8 to 10 in. in a crazy-quill
pattern. Additionally, the samplers were limited by the number of
samples which could be collected and processed through the lab-
oratory. Seven sample points had been specified in the Plan.
A field decision was made to collect six samples from the upper
2 in. of clay. The seventh sample was collected at a depth of 2 in.,
and another sample was collected by tearing out a chunk of day
and sampling along the base of the crack. This seventh sample
was at the lowest point in the dried pond and was the most likely
to have incorporated contaminated sediment particles.
A second decision was that if the analyses results showed the
samples along the crack exhibiting significantly increased concen-
trations of pesticides, then another phase of sample collection
would be scheduled to include additional depth samples.
Example II
Monitoring well sampling was planned at another site. Then
were a number of wells to be sampled in a limited time; the order
of sample collection was specified as volatile*, semivolatiles,
TOC, TOX, phenols, metals, anions/cations and finally radio-
nuclides. Some prior knowledge existed about the concentration
found of the various contaminants at the different well location.
(volatiles and certain metals had been detected at some wells). AD
samples collected were to be split with the property owner, mean-
ing that double volume was required.
When the well at one location was purged, it was observed to
have a very slow recovery rate. Several days recovery would have
been required in order to collect sufficient volumes to enable
analyses of all the constituents. A field decision was made to
change the order in which the sample containers would be filled
after purging: first, volatiles (as in original plan); second, metals;
third, TOC and TOX. After the well recovered, semivolatiles and
anions/cations were to be collected. The remaining analyses were
dropped because the volume after recovery was not sufficient to
include them. It was a management decision to spend 5 hours
rather than 3 days sampling at this location.
Example III
In a dioxin sampling study described in another section of these
Proceedings,' the Sample Plan called for conformity with Na-
tional Dioxin Study protocols. One requirement specified that soil
be collected with a 4-in. tulip bulb planter.
Field trials showed compacted soil (which the tulip bulb planter
could not penetrate) and unconsolidated material in sedimenta-
tion pathways (i.e., loose soil and gravel) which would not stay
together in a core as intended. The problem had been anticipated.
Garden trowels with measures graduated in inches had conse-
quently been included in the sampling gear. These trowels were
used to collect an equivalent sample volume (the uppermost 4 in.
of soil) at each sample location.
HELD EXPERIENCE AS A PREREQUISITE
FOR AUDITORS AND REVIEWERS
Observations of the process have demonstrated the liabilities of
-------
employing field auditors with little pertinent field experience.
Deviations from the approved Sample Plan may be noted, but the
auditor has no perspective within which to evaluate the
significance of the perceived deviation. Thus a minor substitution
of sampling tools may be noted, and the significance of the event
cannot be distinguished from something as major as the lack of
adequate decontamination procedures between two sampling
locations where the same sampling tool was used or the substitu-
tion of an inapproproate drilling method during installation of a
monitoring well.
Field experience is also important during the independent
review of the plan by knowledgeable reviewers. Otherwise there is
the possibility that independent, non-approved operating pro-
cedures inadvertently may become incorporated into the pro-
tocols with the resultant possibility of not achieving the desired
data quality objectives. An independent qualified reviewer is in
the position to compare the written plan with the objectives and
answer the question, "Does this procedure enable the gathering
of evidence to support this goal?"
Currently, field audits of Superfund projects in U.S. EPA
Region IX are performed on approximately 10% of the total
sampling projects. The auditors are experienced field staff who
are trained in field sample collection and who could serve as ex-
pert court witnesses in the event of an enforcement challenge.
The report of the field audit is a memo stating:
• Whether or not the Sample Plan was followed substantially
• The nature and significance of any observed deviations
• Whether or not the sample effort was valid to meet the study
objectives
Audit results receive appropriate and timely followup to correct
identified problems within the monitoring systems. When generic
problems with a specific group are found, immediate manage-
ment attention is devoted to solve the difficulties through train-
ing, discussion, reorientation of personnel or other appropriate
remedies.
CONCLUSIONS
It has been found in the Sample Plan review, tracking and audit
system that the described process helps organize the various com-
ponents of the Superfund site field project. A number of teams
can be deployed to deliver their own expert contributions, and the
entire project coalesces and provides needed answers on the extent
and type of contamination. The field audit supports the process
by verifying that the sample objectives have been met and that
any significant deviations have been noted and corrected.
REFERENCES
1. Simanonok, S. and Beekley, P., "Dioxin Contamination of Historical
Phenoxy Herbicide Mixing and Loading Locations," Proc. National
Conference on Uncontrolled Hazardous Waste Sites, Washing-
ton, D.C., 1986.
SAMPLING & MONITORING 147
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The Importance of Field Data Acquisition in
Hydrogeologic Investigations at Hazardous Waste Sites
Richard J. DeLuca
OCA Corporation
Bedford, Massachusetts
ABSTRACT
Hazardous waste site investigations and remediations are de-
pendent on the sampling data collected during Field activities.
These data are the foundation of all engineering remediation de-
sign. Field data collected that are not representative of sampling
media can result in inappropriate decisions, reduced efficiency in
a remedial measure of even the selection of an ineffective tech-
nique.
Because groundwater impact is often a major concern at haz-
ardous waste sites, the acquisition of the geohydrologic informa-
tion is of the utmost importance in site remediation decision-mak-
ing. Decision-making in remedial design based on erroneous data
will inherently slow the cleanup of hazardous waste sites through-
out the country.
Close coordination between scientists and engineers during the
Remedial Investigation is essential to design a Held program that
will supply the necessary data to evaluate the remedial options
applicable to the site.
INTRODUCTION
The identification, prioritization and remediation of Haz-
ardous Waste Sites are primary objectives of CERCLA. In the
assessment of Hazardous Waste Sites, the acquisition of field data
is extremely important to the decision-making process. Informa-
tion collected during site identification and prioritization often
is used to plan and implement the Remedial Investigation and,
subsequently, to characterize the fate and migration of the waste
and the associated risk to public health and the environment. Re-
medial Investigations are conducted to define the extent of the
problem and provide adequate information to identify the appro-
priate remedial technology.
Since the authorization of CERCLA, it has become apparent
that groundwater contamination is the predominant problem
associated with many hazardous waste disposal sites. Since the
enactment of this legislation, the installation of groundwater
monitoring wells has increased dramatically. The National Well
Water Association reports that 39,084 monitoring wells were in-
stalled at hazardous waste sites in 1983, compared to 121,294
monitoring wells installed in 1985.' Guidance documents have
been developed by Federal and state agencies, consultants and
professional societies to standardize the selection, installation,
construction and sampling of groundwater monitoring wells.
Many technical papers have identified inherent problems with
existing technology and statisticians have shown that human error
can affect chemical analysis. Evaluation of the hydrogeologic
environment, through data collected and interpretation, has been
and will continue to be an area that will come under much scru-
tiny by scientists and engineers in the assessment and remedia-
tion of hazardous waste sites.
The following text discusses two commonly used groundwater
remedial technologies and how the collection of the field data
can affect the decision-making process during remediation. It
also recommends an approach that will increase the efficiency of
the investigations and remediation of groundwater contamina-
tion.
GROUNDWATER REMEDIATION
The ideal approach to the remediation of contaminate^
groundwater is to remove or neutralize the contaminant source
and capture and treat the affected groundwater. Unfortunately,
removing the source is rarely the most economical or desirable
approach. Feasibility studies are conducted to select the mast
cost-effective remedial technology that protects public health and
the environment.
These studies are largely dependent on the data base devel-
oped during the Remedial Investigation. Two groundwater re-
medial options frequently evaluated in feasibility studies are
contaminant barriers and groundwater control, or pump and
treat.
In contaminant barrier remediation, a cap is commonly in-
stalled over/around the contaminant source area to minimize
leachate generation and retard migration, while vertical walk are
installed to a specified depth and tied into a horizontally contin-
uous unit, referred to as a key-in unit. This key-in unit must be a
confining layer and be of sound structural and hydraulic integ-
rity so a good seal between the vertical wall and the key-in unit
can be obtained. The vertical walls typically are composed of a
combination of bentonite, cement and natural fill. Contaminant
barriers are not intended to reduce contamination but may effec-
tively capture contaminated groundwater and minimize the
spread of contamination. In many cases, the barrier system will
require some type of upgradient groundwater diversion to pre-
vent excessive hydraulic gradient buildup.
Groundwater control/pump and treat is also an increasingly
common approach to groundwater remediation. Contaminated
groundwater, once extracted, can be treated to predetermined
contaminant concentrations and released. To enhance this remed-
iation, the treated water can be injected or released upgradient of
the existing recovery system to recirculate and help flush the
contaminated portion of the aquifer. It is important to note that
the treated water must be released within the cone of influence
of the recovery system. Recent studies have shown that the addi-
tion of nutrients to the treated water, prior to the release through
the injection well, can accelerate the biodegradation of certain
hydrocarbons.1
Both of these technologies require an extensive data base to
148 SAMPLING & MONITORING
-------
evaluate these options. This data base is generated during the re-
medial investigation and is extremely important for a success-
ful remediation.
DATABASE
Remedial Investigations are typically large-scale multi-disci-
plinary studies aimed at addressing several overall objectives.
Two major objectives of Remedial Investigations, in which
groundwater contamination is the focus, are the characterization
of the hydrogeologic setting and the determination of the con-
taminant distribution profile.
The hydrogeologic data base is comprised of subsurface in-
formation available through regional and local maps and existing
borings. Regardless of the amount of regional information, col-
lecting site-specific information always is required. Collecting this
information is the primary objective of the Remedial Investiga-
tion. There is no mathematical formula to determine the neces-
sary number of data points to adequately define the hydrogeo-
logic environment. The number of wells and borings is dependent
on the complexity of the strata, the type or types of aquifer(s)
and the variety of chemical compounds found at the site.
Four common examples of aquifer systems are sedimentary,
alluvial, glacial and igneous/metamorphic. A brief description of
some specific variables is identified for these four systems.
Sedimentary environments, generally, are the least stratigraph-
ically complex of the four but may, depending on the sequence,
contain several water bearing units. In the multi-unit case, the
number of monitoring wells installed to define water bearing units
may exceed the number of wells required to define the aerial
contaminant distribution. This is especially true of contaminants
that have specific gravities in excess of 1.0.
Alluvial aquifers deposited by rivers and streams often will re-
quire extensive permeability tests and grain size analysis to deter-
mine hydraulic conductivities throughout the deposit.
The average grain size found in alluvial deposits can vary con-
siderably and may vary from fine silt (found in flood plains) to
coarse sand and gravel (typical of alluvial fans). The data col-
lected prior to and during the drilling activity are extremely im-
portant in the evaluation of contaminant pathways through allu-
vial aquifers.
Hydraulic conductivities in glacial aquifers can vary widely.
Grain size and grain sorting are important parameters in the data
base. Depending on the type of deposit, grain size can be quite
uniform (as in an outwash plain deposit) or heterogeneous (as
in glacial moraines). Glacial features can be identified using topo-
graphic maps and visual reconnaissance. Subsurface stratigraphy,
however, generally can be confirmed only by drilling.
Most igneous and metamorphic rocks have extremely low hy-
draulic conductivity, and groundwater movement is controlled by
secondary porosity (i.e., fractures and joints). The data base for
hydrogeologic investigation in igneous and metamorphic rock in-
cludes regional fracture information obtained from aerial
imagery. The effectiveness of monitoring wells installed in bed-
rock is extremely dependent on the interception of fractures.
Predominant flow patterns often are linear in fractured bedrock
and frequently are oriented parallel to regional strike of larger
scale features (folds and faults).3'4
These four types of aquifer systems can include unconfined as
well as confined groundwater which can add to the complexity of
the evaluation. Definition of the hydrogeologic regime is essential
to the successful design and construction of contaminant barriers
and groundwater control systems.
It is also essential to develop a suitable data base in chemical
contamination throughout the subsurface. The chemical data
base is generated from analysis of samples collected from the con-
taminant source areas and migration pathways (e.g., ground-
water, surface water, air, soil). To assess the migration patterns
of contaminants, a thorough understanding of the physical prop-
erties of the individual contaminants is needed.
Variations in the chemical data base can be caused by the drill-
ing technique, well construction and sampling. Selecting a drill-
ing technique and well construction specifications should take
into account the potential effects of the drilling fluid, grouts and
well construction material. The sampling data base should include
more than one round of sampling and sufficient QA/QC sam-
ples (blanks and duplicates).
The generation of the chemical data base, in conjunction with
the hydrogeologic information, must be carefully planned and
implemented so the selected remedial technology will be both
appropriate and effective.
Two examples are presented to illustrate how the collection of
field data can adversely affect site remediation.
EXAMPLE #1
This site is situated on a fine grain glacial outwash formation.
The strata consists of fine sand and silt varying in thickness from
10 to 60 feet. The water table was within 20 ft of the ground sur-
face. An undetermined amount of hydrocarbon fluid (less dense
than water) was being released into the subsurface.
A preliminary set of monitoring wells was installed into the un-
consolidated deposits with 10-ft screened intervals. These wells
were single well installations designed to intercept the water table.
A floating hydrocarbon layer was detected in one of the wells;
however, the lateral boundary of the hydrocarbon layer could not
be determined. Subsequently, additional monitoring wells were
installed to provide data to be used for site remediation. Follow-
ing the installation of the additional wells, a map identifying the
lateral limits of the hydrocarbon layer was developed. A recovery
system was installed that consisted of the installation of one large
diameter well designed to induce a cone of depression (with a sub-
mersible pump) to draw in the hydrocarbon layer. A second
pump, or scavenger pump, would then collect the hydrocarbon
layer. The remediation attempts were largely unsuccessful. The
surrounding monitoring wells began to show increasing volumes
of hydrocarbons with little or no hydrycarbon fluid in the re-
covery well during operation.
Review of the study revealed the absence of very important
field data which made calculations of hydraulic conductivity
values impossible and resulted in the selection of an ineffective
remediation. During the installation of the preliminary wells, too
few overburden samples were collected to define the average
grain size. Screening intervals were not located to monitor the
water table. The installed screen slot size was too large and
allowed excessive sedimentation, and, in some cases, sediment
buildup extended upwards to the seasonal high water table. The
second set of wells also used the same screen slot size and had the
same sedimentation problem, although to a lesser extent. Screen-
ing intervals were longer and positioned to intercept the water
table. The recovery well was designed based on these wells. How-
ever, in situ permeability tests were not performed and, to the
author's knowledge, no type of aquifer pumping test was per-
formed to delineate the cone of depression.
During the drilling program, borehole permeability tests should
have been conducted to ascertain the permeability of selected
strata. Grain size analysis also would have provided valuable in-
formation for the screen slot size and filter pack selection. Final-
ly, an aquifer pumping test would have provided transmissivity
values necessary for determining the appropriate recovery system.
SAMPLING & MONITORING 149
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EXAMPLE #1
A site located on a sand and gravel aquifer received and per-
mitted the disposal of liquid hazardous waste onto the ground.
The waste percolated to the groundwater and began to migrate
off-site. The degradation of the groundwater and its potential im-
pact on residential groundwater wells downgradient prompted
an investigation. The objective of the investigation was to gather
the necessary field data to plan and implement site remediation.
The immediate remedial option was determined to be the in-
stallation of a slurry wall extending to the bedrock surface. Bor-
ings were advanced until refusal into glacial till. The till was as-
sumed to be continuous and relatively impermeable. At the one
location where bedrock was encountered, the surface was found
to be highly fractured.
The result of this one boring prompted further site character-
ization of the bedrock integrity. The subsequent study found that
the bedrock sloped and the till layer thickened. The assumption
that the till layer extended horizontally proved to be correct.
However, a redesign of the slurry wall was necessary due to the in-
creased depth, and integrity of the bedrock surface.'
Here the key-in unit was the bedrock, and the initial study had
only one boring into the bedrock. The subsequent study enabled
better definition of the till layer and bedrock surface, which
allowed a redesign of the slurry wall. If the original study had
included better definition of the bedrock, the second evaluation
may not have been necessary.
These two examples demonstrate that collecting field data is ex-
tremely important in hydrogeologic investigations and remedia-
tion. Managers, engineers, scientists and regulatory officials all
must be aware of the limitations of the field data collected and
how that data will affect the decision-making process and, ulti-
mately, the remediation effort.
INCREASING THE EFFICIENCY OF
HELD DATA COLLECTION
The author has observed numerous occasions where the data
base compiled during the Remedial Investigation was not suffic-
ient to evaluate the remedial options. In some cases, additional
studies or followup data collection were unavoidable. However,
in many cases, the engineers and scientists developing the feasi-
bility study did not become involved in the project until after the
remedial investigation, and similarly, the remedial investigation
coordinator may not be involved in theoretical applications re-
garding the remedial options. Remedial investigation field data
should provide the appropriate type and amount of data to en-
able the evaluation of all applicable remedial options.
The logical approach to designing a successful program that
will support the Feasibility Study involves first identifying which
remedial options might apply to the site and then designing the
data collection program to provide the required information.
Without this foresight, field data will be collected which may or
may not provide all the necessary information to evaluate the
appropriate remedial technologies.
If the field program is initiated without knowing which remed-
ial techniques are being considered, the following approach will
maximize the likelihood that the data base will be sufficiently
complete to support the subsequent Feasibility Study.
When drilling in unconsolidated formations, split spoon sam-
ples usually are collected every 5 ft and at all strata changes. For
example, in the unconsolidated glacial formations, sand and
gravel lenses are common.' When collecting samples every 5 ft,
these lenses can be missed even by an experienced field geologist.
These lenses, which may have higher horizontal permeabilities,
can provide more rapid and concentrated attenuation of contam-
inants.' If the screening interval does not intercept these lenses,
the contamination may be detected at a lesser concentration or
even be missed altogether, depending on the density and solubil-
ity of the contaminants. Therefore, it may be prudent to collect
continuous split spoon samples at selected wells. Representative
overburden samples from the screened horizons should be sub-
mitted for grain size analysis to confirm field classifications.
Proper monitoring well screening intervals depend not only on
the strata, but also on the objectives of the investigations. In a
preliminary investigative situation, a fully screened monitoring
well may be more appropriate to provide an overall picture of the
groundwater quality. For investigations that likely will spawn a
comprehensive Remedial Investigation, nested wells provide the
hydrogeologist with a much better data base to evaluate the
hydrogeologic environment and the characteristics of the contam-
ination migration.' Regardless of whether the investigation is at
the preliminary stage or the advanced remedial level, field ana-
lytical screening of split spoon samples with portable field mon-
itoring instruments can enhance the likelihood of identifying con-
tamination zones during the drilling activity. Monitoring weO
screening intervals then can be selected to intercept the zones of
interest.
Field analytical screening of split spoon samples can be bene-
ficial in selecting monitoring well screening intervals. However,
field analytical screening should not be the entire basis for the
selection of monitoring well screening placement. Therefore, it
may be advisable to install nested wells to screen the entire length
of the unconfined water table, especially in cases where the con-
taminants are soluble in water or more dense than water. This
approach toward monitoring well screening intervals should pro-
vide sufficient data to evaluate the chemical contamination
throughout the water column.
Monitoring well screen slot configuration should be selected
based on the filter pack material (backfill) which, in turn, should
be selected based on the grain size distribution of the geologic
material. This relationship provides the maximum well efficiency
when the filter pack is evenly distributed in the annulus.' The
use of centering guides to ensure that the screen is centered in the
borehole prior to installing the filter pack will ensure that the
backfill is evenly distributed.
The use of well screens with filter packs is necessary to prevent
the buildup of sedimentation; however, groundwater monitoring
wells seldom are designed for maximum efficiency. This may not
appear important when a data point is used strictly for sampling
and water table elevations, but if well points are used to calculate
permeability values, certain care should be exercised. For ex-
ample, a 10-ft section of 2-in. PVC with a 0.010 in. machine slot
opening has an open area of 3.5%.' If well screens are installed
into stratigraphic units that have an open area of more than
3.5%, then the well screen will be the limiting factor and the
permeability data will be representative of the well screen and not
the formation. For this reason, well screens should have open
areas equal to or greater than the open area of the aquifer.
A 10-ft section of 2-in. continuous slot PVC with a 0.010 in.
slot opening has an open area of 7.6%, which far exceeds that of
the machine slot PVC.I0 The stainless steel version with the same
dimensions has an open area of 14.0%. Since the maximum open
area of a perfect aquifer with rhomboidal packing is approxi-
mately 10%," the continuous slot well screen offers double the
open area and, in most cases, will not be the limiting factor.
An additional problem with in situ permeability tests conducted
after the completion of the well stems from well development.
Every type of drilling operation changes the hydraulic character-
istics in the immediate vicinity of the borehole. Hydraulic con-
ductivity around the borehole tends to be lower than is found in
the undisturbed formation. To restore the formation around the
150 SAMPLING & MONITORING
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borehole to its most representative condition, the monitoring
well must be developed.
Typical development techniques include flushing, bailing,
mechanical surging, air lift surging and pumping and high veloc-
ity jetting. Too often the development technique commonly
chosen is dependent on the equipment readily available to the
driller. This use of opportune equipment may result in the selec-
tion of a less effective development technique. High velocity
jetting has been a highly effective development technique and
should be specified as the development technique. High velocity
jetting will cause volatilization of certain compounds and may
reduce concentrations if the monitoring well is sampled shortly
after development.
Whether drilling is in unconsolidated or consolidated depos-
its, the use of drilling muds should be avoided at all costs. Drill-
ing muds reduce hydraulic conductivities and attenuate contam-
inant concentrations.'2
A relatively new drilling technique shows great promise for the
installation of monitoring wells in formations that require muds
to maintain an open borehole. This drilling technique, featured
in the August 1985 Water Well Journal, is known as the ODEX
method. It employs a retractable air rotary bit that allows the
casing to follow the bit, eliminating the need for drilling mud in
most cases. As currently utilized by Philip Brien (the driller fea-
tured in the article), the casing is rapidly advanced through the
overburden until it reaches bedrock. Once solid bedrock is
reached, the bit is extracted by rotating the drill stem in the oppo-
site direction. The bentonite can be pumped down through a
special injection sleeve while the casing is in place to provide the
seal. As the sleeve is removed, the bentonite is allowed to swell.
Once swelled, a smaller diameter hammer is advanced through the
seal to the desired depth. This method is particularly useful if the
objective of the well point is to monitor the groundwater found
in the bedrock, because it ensures a high integrity seal.
It is quite possible that this technique could be adapted for the
installation of overburden/sedimentary monitoring wells. If this
were the case, the use of muds frequently could be eliminated and
the drilling fluid could be clean water.
The chemical data base obviously depends on the lateral place-
ment of the monitoring well points and their vertical screened in-
tervals. The drilling fluid and well construction are also extreme-
ly important to the groundwater chemistry. If at all possible, the
drilling fluid should be clean water. The use of bentonite (sodium
or calcium) and cement for seals and grouts likely will have ef-
fects on the pH and cation exchange rate." The compatibility of
these materials (and the monitoring well material itself) with the
contaminants of concern should be evaluated prior to use.
The chemical data base is extremely sensitive to sampling pro-
cedures, field conditions, equipment and sample handling. Dup-
licates and blanks (field, trip, equipment) should be a part of all
sampling programs to prevent contamination from the sampling
procedures. Dedicated equipment can be employed to minimize
the potential for cross contamination.
Groundwater sampling often is considered to be simple and
routine. However, this component of data collection can have a
dramatic effect on the Remedial Investigation (and subsequently
site remediation) if it is not performed correctly."
To ensure reproducible data, it is advantageous to conduct
multiple sampling rounds to develop the analytical data base.
Since chemical analysis can be extremely expensive, one ap-
proach may be to perform partial analysis after the original full
comprehensive analysis. Many options exist to provide the analy-
tical data base without exhausting available resources.
CONCLUSIONS
The importance of appropriate field data collection cannot be
overemphasized. Collection of unrepresentative field data or re-
liance upon field data beyond its limitations most likely will lead
to unsuccessful site remediation or increased costs due to addi-
tional investigation.
With the increasing number of monitoring wells being installed
at hazardous waste sites each year, it is extremely important that
all investigative programs provide the maximum amount of data.
It is especially important for those sites where some type of re-
medial technology is to be planned and implemented. If these
technologies are identified prior to the Remedial Investigation,
the collection of field data will be more likely to provide the
necessary data base to properly evaluate the applicable remedial
options.
REFERENCES
1. Jagucki, P., Personal Communication—NWWA.
2. Jhaveri, V. and Mazzacca, A.J., "Bio-Reclamation of Ground and
Groundwater Case History," Proc. National Conference on Man-
agement of Uncontrolled Hazardous Waste Sites, Washington,
DC, Nov. 1983, 242-247.
3. Jenkins, D.N. and Prentice, J.K., "Theory for Aquifer Test Analy-
sis in Fractured Rock Under Linear (non-radial) Flow Conditions,"
Groundwater, Jan.-Feb. 1982.
4. Buckley, B.K., DeLuca, R.J. and McGlew, P.J., "Hazardous
Waste Investigations in Fractured Bedrock," NWWA Eastern Reg-
ional Conference, July 1985, Portland, ME.
5. DiNitto, R.G., "Evaluation of Various Geotechnical and Geophysi-
cal Techniques for Site Characterization Studies Relative to Plan-
ned Remedial Action Measures," Proc. National Conference on
Management of Uncontrolled Hazardous Waste Sites, Washington,
DC, Nov. 1983,130-134.
6. Driscoll, F.G., Groundwater and Wells, 2nded., Johnson Division,
1986.
7. Freeze, R.A. and Cherry, J.H., Groundwater, Prentice Hall, Engle-
wood Cliffs, NJ, 1979.
8. Maslansky, S.P., Kraemar, C.A. and Henningson, J.C., "An Eval-
uation of Nestled Monitoring Well Systems."
9. Timco Geotechnical Products Catalog, 1984.
10. Smith, A., Personal Communication, Johnson Division-Technology
Services.
11. Clark, L. and Turner, P., "Experiments to Assess the Hydraulic
Efficiency of Well Screens," Groundwater, May-June 1983.
12. Jennings, K.V.B., "The Effects of Grouts, Sealants and Drilling
Fluids on the Quality of Groundwater Samples."
13. McKown, G.L., Schalla, R. and English, C.J., "Effects of Uncer-
tainties of Data Collection on Risk Assessment, Proc. National
Conference on Management of Uncontrolled Hazardous Waste Sites,
Washington, DC, Nov. 1984,283-286.
SAMPLING & MONITORING 151
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A Practical Methodology for Designing
And Conducting Ambient Air Monitoring
At Hazardous Waste Facilities
Mark J. Asoian
Woodward-Clyde Consultants
Denver, Colorado
Michael J. Barboza, P.E.
Louis M. Militana
Woodward-Clyde Consultants
Wayne, New Jersey
ABSTRACT
The body of information presented in this paper is directed to
those scientists charged with designing and conducting ambient
air monitoring for air toxics at hazardous waste or other facilities.
The emphasis is on preliminary planning of the monitoring pro-
gram and the decision paths required to develop a successful pro-
gram. A decision tree approach is suggested in which the goals of
the program are set by asking the basic questions of who, what
and for whom. Three basic reasons why toxic air monitoring may
be required are: (1) to support an on-site health and safety pro-
gram; (2) to evaluate ambient levels to which the public may be
exposed, and (3) to determine a facility's contribution to ambient
air toxic levels.
Development of a project-specific monitoring plan is recom-
mended, and the suggested contents are presented. Instantan-
eous, continuous and integrated air samples are defined and dis-
cussed. A summary of various sampling methods falling under
these categories is presented. An overview of QA/QC require-
ments for both monitoring and analysis procedures also is pre-
sented. Finally, several case studies of various air toxic sam-
pling applications are discussed.
INTRODUCTION
Recent ambient air monitoring efforts conducted for a variety
of hazardous waste facilities have underscored the lack of spe-
cific guidance available for designing and conducting such pro-
grams. The majority of existing technical guidance is directed
toward specific sampling and analytical procedures. Little atten-
tion has been given to the overall monitoring effort, the design
or the conduct of the monitoring program as a whole. This situa-
tion can be likened to conducting a prevention of significant
degradation air monitoring program with guidance only for oper-
ating sampling equipment and performing analytical procedures.
Conducting ambient air monitoring for air toxics is becoming
more important as regulatory requirements for monitoring in-
crease at hazardous waste facilities. This importance also stems
from the increase in adjudicatory proceedings involving liability
issues associated with the release of hazardous air contaminants,
whether from facilities defined as hazardous waste facilities or
from other sources. Regardless of the catalyst, the objective is to
determine the existence, magnitude and extent of toxics in the
ambient air. The overall trend in monitoring requirements ap-
pears to be leading to the protection of the public health and
welfare from ambient air toxics in a manner similar to that more
traditionally associated with criteria pollutants.
An important implication (for regulatory or adjudicatory pur-
poses) of protecting the public health and welfare from adverse
152 SAMPLING & MONITORING
ambient air toxic levels, aside from the problem of defining ambi-
ent levels which are adverse, is consistency of approach to the
monitoring effort. The authors' intent is to suggest a consistent
approach for designing and conducting ambient monitoring pro-
grams for evaluating ambient levels of air toxics at hazardous
waste facilities or for similar applications. Practical guidance
provided is derived primarily from methodologies used to develop
and conduct monitoring programs for criteria pollutants and re-
cent experience in conducting a variety of ambient air toxics sam-
pling programs. Several case studies upon which this paper was
based are discussed, including a retrospective review of the ad-
vantages and disadvantages of the monitoring programs. A dis-
cussion on the relative usefulness of the data obtained is in-
cluded, as well as a discussion of the problems encountered and
steps taken to resolve them.
DECISION TREE APPROACH
A decision tree approach has been suggested to facilitate de-
signing and conducting ambient air monitoring programs for
toxics at hazardous waste and other facilities. The approach is de-
picted in a simplified decision tree presented in Fig. 1. An essen-
tial part of the approach is identification of program objectives.
The reason for the monitoring program is the most important
question that should be asked: "Why is the program being con-
ducted?" Once the program objectives have been established, the
Program Planning can begin. By answering additional ques-
tions (Fig. 1), one can design the program. Additional ques-
tions must be considered for program implementation. As the de-
cision process continues, the more subtle issues are identified,
thus completing the process and filling out the decision tree and
defining the scope and content of the air monitoring program.
OBJECTIVES
The initial aspect of the decision process (Fig. 1) is the deter-
mination of WHY the monitoring will be conducted. Although
this question is basic to all monitoring programs, it is perhaps
more essential to ambient air toxics programs, as the answer sets
the course of the entire program. The answer to why a program is
being conducted can be classified into one or more of the follow-
ing three major categories:
• To determine a facility's contribution to ambient contami-
nant levels and regulatory compliance
• To support on-site health and safety efforts
• To investigate ambient levels to which the public may be ex-
posed
Each of these major reasons for a monitoring
-------
cussed below.
Figure 1
Air Monitoring Program Decision Tree
Contribution to Ambient Contaminant Levels
To adequately determine the contribution from a given facility
to ambient contaminant levels requires an upwind, downwind
monitoring network. This is particularly true if the facility in
question is located in an area with other facilities contributing to
ambient contaminant levels. Under this scenario, the concern is
not to determine instantaneous or acute contaminant levels or
even to determine chronic levels, but rather to determine long-
term (1 to 24 hr) ambient concentrations as accurately as pos-
sible. Attention must be paid to fluctuations in wind direction,
as source/receptor alignment is critical to obtaining meaningful
results from the monitoring. Additionally, a high degree of sen-
sitivity in both the sampling and analysis procedures may be
necessary to distinguish between very small changes in contam-
inant levels from one sample location to another.
Health and Safety
The primary focus of on-site health and safety programs is to
protect personnel from the acute and/or chronic effects of ex-
posure to toxics. With respect to air quality, protecting against
acute or chronic effects requires separate and distinct monitor-
ing approaches. Each approach utilizes unique and specialized
sampling equipment with associated operational and analysis re-
quirements. Therefore, one must determine which type of ex-
posure protection is necessary to develop a suitable monitoring
program.
Acute
Protecting against potentially acute effects of exposure to air
toxics implies the need to determine real time contaminant levels
on a continuous basis. Typically, the equipment used for this pur-
pose would be portable, providing a continuous readout of con-
taminant concentrations as referenced to some standard. Exceed-
ing a predetermined action level would then trigger implementa-
tion of a contingency plan. The shortfall of these types of moni-
toring devices is their inability to accurately qualify and quantify
the (all) types of contaminants present. However, they do satisfy
the primary goal by providing a real time indication of ambient
air toxic levels without the need for time-consuming and expen-
sive sample collection and analysis.
Chronic
Protecting against potentially chronic effects of exposure to
ambient hazardous air contaminant levels implies the need to
identify and quantify the types(s) of contaminants present.
Equipment used for this purpose is portable and can be used
stationary or on personnel. This equipment samples a known
quantity (volume) of air for a specified sampling time (typically
1 to 24 hr). Although this type of sampling does not readily allow
for field analysis, a very accurate determination of the type(s)
and concentrations of air contaminants can be made. This type
of analysis is crucial in determining potentially chronic effects of
air toxics, as the effects will vary by contaminant, by concentra-
tion and by length of worker exposure.
Public Exposure
Evaluation of ambient hazardous air contaminant levels to
which the public may be exposed usually requires a determina-
tion of fence line contaminant levels. This requires sampling at
more than one location to account for changes in wind direction
that may occur during the sampling period. It is assumed that
fence line concentrations represent the maximum level to which
the public may be exposed. Since concentrations will decrease
with transport from the property. Under some situations, it also
may be necessary to monitor ambient hazardous air contam-
inant levels at nearby residences. In the majority of evaluations
of contaminant levels to which the public may be exposed, the
concern will be to identify and quantify contaminants with the
potential to cause chronic effects.
PLANNING
Answering the planning questions posed on the decision tree
(Fig. 1) will clearly define the methods required to achieve the
identified program objectives. Development of a project-specific
monitoring plan encompassing all the issues raised in the decision
process is essential. Regardless of which branch the decision
process follows, a monitoring plan of one form or another should
be developed. Prior to developing the monitoring plan, all the
issues outlined on the decision tree should be addressed, with
project-specific issues included in the monitoring plan. Suggested
contents of a monitoring plan are presented in Table 1.
Air Sampling Methodologies
An integral part of the monitoring plan is to determine and
develop the sampling methodologies to achieve the goals of the
monitoring program. Sampling for specific hazardous com-
pounds, especially organics, in the ambient air can be extremely
complex. This complexity is due to the high degree of variability
associated with measurement of air contaminant concentrations
including source variability, meteorological variability, spatial
variability, personnel activity variability and influence of extran-
eous sources variability (on-site or off-site). Adding to the com-
plexity of the monitoring task are the wide variety of contam-
inants of interest and the lack of standardized sampling and
analysis procedures.
An initial step toward establishing some standardization of
sampling and analysis procedures is presented in a compendium
of specific guidance in Table 1—Suggested Contents of Air
Toxics Monitoring Plan determination of selected toxic organic
compounds in ambient air.' At present, the compendium is lim-
ited to guidance on five methods utilizing different collection
media. The various methods and types of equipment available
for conducting air sampling analyses are related to the kinds of
contaminants of concern, the range of contaminant concentra-
tions expected and the sampling period and sampling duration.
Some sampling methods are specific to a single contaminant,
while others will respond to many different contaminants and
provide total gross indications of the possible presence of many
contaminants. Some methods allow determination of a contam-
inant in different ranges and have different sensitivities (min-
imum detectable limits) to various contaminants. Some methods
provide sampling results over different time periods due to in-
SAMPLING & MONITORING 153
-------
Table 1
Suggested Contents of Air Toxics Monitoring Plan
Table!
Summary of Air Sampling Methodologies
1.0 INTRODUCTION
Purpose
• Scopt
• Objective!
2.0 SITE DESCRIPTION
• Topographic Inscription
• Land UM Oticrlptlon
Source Description
• Climatologies! Description
3.0 MONITORINS PROGRAM DESCRIPTION
• Monitoring locations (relationship to sources, property boundaries.
structurts, etc.
• Photographs
• Instrumentation (sir quality «nd •eteoroloey)
• Collection MedU (type, prepsrstton. quantity)
• Monitoring Schedule (averaging, period, frequency, duration)
• Operating Procedures (f lo. rates. volumes)
• Maintenance Procedures
• Staple Handling Procedures (Installation, shipment)
• laboratory Procedures (saeailo preparation, ewthods. sensitivity)
4.0 DATA PROCESSING AND REPORTING
• Format
• Frequency
• Content
5.0 QUAIITT ASSURANCE (field, laboratory, reporting)
Calibration Frequency
• Independent Audit Program
• Internal Quality Control Procedures
• Data Precision and Accuracy Calculation Procedures
• Blank (field, laboratory)
• Duplicates
• Breakthrough
• Spikes
• Cheln-of-Custody
6.0 REFERENCES
tam>1> atwlti Riwtti Umil
•^-- '•« JIB tesl_ nmm. tea,
herent properties of the method and equipment involved. A sum-
mary of air sampling methods is presented in Table 2.
The different types of air samples obtained can be classified
according to sampling duration. The three classifications are:
• Instantaneous samples
• Continuous samples
• Integrated samples
Instantaneous samples are those which are collected instantan-
eously over an extremely short period of time in the range of a
few minutes or less. Continual sampling can be accomplished by
continually taking instantaneous samples. These often are refer-
red to as grab samples. Continuous monitoring includes methods
which provide a continuous readout of instantaneous changes in
concentration. This method usually utilizes a continuous instru-
ment with a constant meter readout and sometimes is used with
a chart recorder to provide a continuous record of contaminant
concentration levels with time. Integrated samples are those col-
lected over a time period usually in the order of an hour or more,
extending to a day or, in some cases, a number of days. The re-
sult of integrated sampling provides a given value which is essen-
tially an average value for the sampling period of concern.
Sampling methods can be classified further by the physical
and chemical properties of the contaminants of concern. Physi-
cal properties that must be considered include: boiling point,
vapor pressure and solubility. Compounds with low volatility
(boiling points greater than 200 °Q may exist as paniculate mat-
ter, while compounds with higher volatility usually will be in the
gas phase. Sampling techniques can vary greatly depending on
whether compounds exist in the gas phase, solid phase or are
particulate-bound.2
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Diucur li*M Re-lia •'»"'" a«* «N
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I rt«t (tract 0.*
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rieu ec IMUMMMH Niuaric, lirect o.ool-o.l Nnt OrfMicf n*& an
linmn IM»r«U< Start Time a^Mlne mn Inilii.
•elay •«!«•
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UlUrlc U» Vvl*l< TMal tr
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tliMn exl fM tlract 1-10
Iimrmmilei * uvw
Paniculate Sampling
Filtration is a sample collection technique most commonly
used for sampling paniculate matter and other paniculate-bound
components. Various filter media are available, and some art bet-
ter suited to collection of certain compounds. Filtration media
include:
• Cellulose
• Glass or quartz fiber
• Membranes
• Teflon coated glass fiber
Paniculate sizing may be of interest in some situation, and
there are techniques available for this. However, particle sizing
can increase the complexity of sampling.
Examples of particulates or particle-bound components in-
clude: fugitive dusts, trade metals, PCBs and coal tar volatile.
Methods for sampling PCBs utilize polyurethane foam (PUP)
with both low volume and high volume sampling systems.'
Gas Sampling
A number of different techniques are available for sampling
gas phase compounds. Selection is important because some tech-
niques are better suited to sampling certain compounds and not
others. Available techniques include:
• Colorimetric detector tubes
• Solid/liquid adsorbents
• Grab sampling (bags, rigid containers)
• Flame ionization detectors (FID)
• Photoionization detectors (PID)
• Infrared analysis
Meteorological Monitoring
The importance of acquiring meteorological data concurrent-
ly with ambient air data can vary significantly. However, in al-
most every air monitoring situation, the acquisition of some form
of meteorological data is required. The parameters required from
one monitoring program to another may vary, but in almost every
situation, some determination of wind direction and wind spew
is essential. Depending on the overall goals and duration of the
monitoring program, the meteorological monitoring equipment
154 SAMPLING & MONITORING
-------
may vary from a wind sock to a fixed 10-m instrumented tower
with strip chart or cassette recording devices.
Quality Assurance '
The overall objective of quality assurance/quality control
(QA/QC) is to increase the level of confidence of the sampling
or measurement data of air contaminant concentrations. Quality
control can be considered normal procedures and activities (rou-
tine checks, calibrations, duplicate samples, split samples, blanks
and spiked samples) that increase quality of results. Quality as-
surance consists of activities that provide assurance that the qual-
ity control functions are performed adequately. In air toxic sam-
pling, the terms QA/QC commonly are used collectively to indi-
cate a variety of procedures and activities utilized to meet the
overall objective of improving data quality.4 QA/QC elements
of an air toxic sampling program commonly include:
Calibrations (routine and audit)
Document control
Data validation
Prevention maintenance (equipment)
Training
Inter- and intra-laboratory testing
Cross-methodology correlation/verification
Some of these elements should be part of all air sampling pro-
grams, while others may be included in larger sampling efforts.
QA/QC activities pertain to field sampling efforts as well as
laboratory analysis. Laboratory analysis QA/QC activities usual-
ly are easier to implement than those for field activities; it is often
simpler to control variables in the laboratory, as most labora-
tories have formal QA/QC plans and participate in inter-/intra-
laboratory testing programs. QA/QC activities for field sampling
efforts include:
Calibration (zero/span checks)
Sample duplicates/split samples
Sample blanks
Spiked samples
Standard reference materials
Co-located samplers
Cross-method correlations
Documentation
Calibration of field sampling systems is an integral part of
QA/QC activities and should be performed. Calibrations should
include flow rates, volume, pressure, temperature and other
meteorological factors. For continuous meters, calibrations
should include precision and accuracy checks with zero and span
gas responses and use of standard reference materials, certified
gases or standard traceable calibration gases. Since field efforts
tend to be expensive, consideration should be given to collecting
duplicate samples during the initial field effort because additional
sample collection cost is usually minimal compared to the pro-
gram as a whole. Decisions regarding analysis of duplicates can be
made after the field effort, since laboratory costs increase propor-
tionally with the number of samples analyzed. If possible, it is
often more advantageous to corroborate results by using multiple
methodologies (i.e., detector tubes, absorption tubes, bags, etc.)
Flow rates and volume measurements should be calibrated us-
ing primary standards (i.e., bubble flow meters or wet test meters)
and/or checked with transfer standards (i.e., calibrated
rotometers or mass flow meters).
Documentation is an important aspect of QA/QC since it
allows verification of QA/QC activities that have been performed
and also provides an indication of the overall quality of the re-
sults of a sampling program. The advantages of having a paper
trail documenting activities cannot be overemphasized, especially
for ambient hazardous air monitoring programs where data may
be required by regulatory authorities used for litigation, remedia-
tion design or assessment of public risk. Examples of documen-
tation include field logs, data sheets, calibration records and
chain of custody forms.
A major benefit of utilizing QA/QC programs is that prob-
lems may be detected in the early phases of the sampling pro-
gram, thus allowing implementation of corrective actions or pro-
gram modifications with minimal loss of data or time.
IMPLEMENTATION
One of the major questions regarding program implementa-
tion (Fig. 1) is who is to conduct the monitoring. Expertise is re-
quired in program design and field implementation. Is the special-
ized expertise required available in house? Laboratories that have
GC equipment do not always possess the capabilities to satis-
factorily handle air samples. Care should be taken when selecting
air analysis laboratories. A frequent concern with regard to air
analyses is the turnaround time. Due to recent demand, delays
in receiving analysis results can be quite common.
Another major consideration is program cost. Costing may be
considered a planning function. However, the program should be
planned first, costed and then reevaluated as needed to assess the
program with regard to costs versus benefits. The benefits usual-
ly are associated with the level of confidence in the results or the
degree of uncertainty with regard to concentrations of air tox-
ics. Major costs can be assessed as labor, equipment and labor-
atory charges. Cost for continuous equipment can require high
cost initially. However, major costs of air toxics monitoring are
usually associated with laboratory charges.
CASE STUDIES
Several case studies are presented below which show the wide
variety of applications for monitoring of hazardous air contam-
inants at hazardous waste and other facilities.
Hazardous Waste Landfill Site
The site in question is an inactive 24-acre site which was used to
landfill industrial process wastes generated from the mid-1960s
to 1977. Process wastes included salts and cell bath (barium,
calcium and sodium chlorides), contaminated discarded cell rub-
ble, a variety of chlorocarbons and other organic and inorganic
wastes.
The site was closed in 1977, and a clay cap was completed in
1978. A groundwater recovery system was installed to remove and
treat contaminated groundwater and reduce off-site transport of
contaminants with groundwater. As part of an endangerment
study, a review (including modeling) of the air pathway raised
some concern regarding airborne contaminants due to potential
for volatization of chemicals and subsequent off-site transport.
An ambient air sampling program including sampling for selected
contaminants and meteorological parameters was initiated at the
site to provide more information regarding airborne concentra-
tions of site contaminants.
Due to the different natures of the contaminants of concern,
three different sorbent media were used. These included Tenax
for volatile nonpolar organics, Carbon Molecular Sieve (CMS)
for highly volatile organics (i.e., vinyl chloride) and inorganics,
and XAD for compounds such as hexachlorobutadiene.
The objective of the sampling was to establish the potential for
air contaminants coming from the site. A major concern was the
potential for interferences from other waste sites and/or indus-
trial sources in the area. Five sampling locations were used to
collect concurrent upwind and downwind samples required to
isolate and identify emissions from the site and any potential
SAMPLING & MONITORING 155
-------
off-site upwind sources. The sampling period was three days dur-
ing different times of the year to obtain data on seasonal vari-
ability.
Some insights associated with this air sampling program in-
volved the sensitivity and selectivity of the methods. In many
cases, as in this one, the concern is associated with long-term
low level releases and not necessarily acute short-term releases.
Therefore, it is necessary to push to the limits of both ana-
lytical and sample collection sensitivities in order to be able to
make meaningful conclusions. The results obtained have been ex-
tremely low and mostly below detectable limits. Indication of up-
wind off-site sources of some contaminants of interest was found.
Firefighter Exposure Study
This study consisted of designing and implementing an air
monitoring program to monitor firefighter exposure to toxic ma-
terials encountered during firefighting operations. The air mon-
itoring program is part of an overall health hazards study of fire-
fighters in a large municipality. The study also included a med-
ical surveillance program with an objective of correlating air
monitoring and medical testing results. A varying number of
chemical compounds can be produced and released during Tires.
Many variables control the types of compounds that become by-
products of combustion with the most important variables be-
ing the type of material which is burning, the temperature at
which it burns and oxygen concentration present. The combus-
tion of material containing nitrogen, sulfur and halogens in the
presence of carbon and hydrogen can form hydrogen cyanide,
nitrogen oxides, sulfur dioxide, ammonia and halogen acids.
Other toxic chemicals of concern are halogens, aldehydes and
vinyl chloride.
The study focused on two firehouses with the reported highest
number of fire incidents in the City of Buffalo. These fire houses
are comprised of approximately 100 Firefighters. Over 50 of the
100 firefighters actually participated in the air monitoring pro-
gram.
The air monitoring program required the use and assembling
of specialized sampling equipment that would sample the air for
various toxic compounds, be worn by firefighters without
hampering them during performance of their normal duties and
also stand up to the hostile environments to which firefighters
commonly are exposed. The equipment included sampling
pumps, colorimetric detector tubes, sample manifolds, adsor-
bent tubes, paniculate filters, temperature monitors and a carrier
pack.
Personal samples were collected in the breathing zones of the
firefighters during their responses to incidents. If respiratory pro-
tective equipment was being worn, samples were collected out-
side the face pieces. The samples collected represent the potential
inhalation exposure of firefighters not wearing respiratory pro-
tection. Samples were collected during various stages of fire-
fighter activities (i.e., rescue, fire control, overhaul).
The air monitoring was performed over a 10-day period in Jan-
uary of 1986. During this period, the two firehouses involved in
the study responded to 106 calls, 14 of which were of sufficient
duration and magnitude to monitor. The characteristics of these
fires (i.e., type, activities, smoke intensity, etc.) and air sampling
information were recorded.
Sampling insights drawn from this study relate to sampling
periods, sample duration and equipment. Although the occur-
rance of fires can be thought of as random, future sampling
efforts should be focused on periods of expected higher frequen-
cies of events. Sampling duration is of concern because of the
great variability associated with different fires as well as the dif-
ferent activities of each firefighter. Recommended modifications
to equipment are associated with cold weather (i.e., tubing) and
156 SAMPLING & MONITORING
also loss of samples from water.
Shopping Center Study
Reports wered received of chemical odors from a number of
small stores in a shopping center complex. The complaints con-
sisted of chemical odors causing varied symptomatic health re-
lated complaints of headaches, nausea, eye and nasal irritation,
etc. Inspections of the most obvious potential causes were per-
formed by respective contractors (i.e., heating and air condition-
ing systems, gas services, fire department). No malfunctions or
leaks were found that could explain the odor. Air sampling wai
performed to identify the type and level of air contamination
present and to locate the source. It was necessary to determine the
extent, if any, of health hazard posed by the contamination and
to locate the source of the odors so that mitigation measures
could be implemented. Immediate response was required.
Four major air quality sampling techniques were used due to
the unknown nature of the type, levels and source of contamina-
tion. The methods used were total volatiles screening, colori-
metric detector tube sampling, adsorbent tube sampling and bag
sampling. Screening for total volatiles was performed with two
photoionization analyzers; a Model PI 101 by HNU System,
Inc. and a TIP by Photovac, Inc. Screening of indicated concen-
trations was performed in the stores and locations where the
problems were reported. The analyzers were used continuously
throughout the area to assess variations in ambient concentra-
tions.
Colorimetric detector tube sampling indicated the presence of
benzene and potentially other aromatic compounds such as
toluene and xylene, compounds indicative of those found in gas-
oline.
Adsorbent tube samples were collected and sent to a laboratory
for analysis. The results confirmed and expanded upon the detec-
tor tube results. Bag samples collected were sent to a different
laboratory whose results supported those of the previous tech-
niques.
A potential source of the gasoline was traced to a storage tank
and filling facility located at an ambulance service on an adja-
cent property. It was suspected that gasoline collecting under the
building could be the result of a leak in the tank, associated pip-
ing and/or spills due to overfilling. Reports of a recent spill/in-
cident due to overfilling and the fact that the complaints were re-
cent and not of a chronic nature indicated that spills due to over-
filling most likely were responsible for the problem.
As a result of this project, we concluded there was a need to
utilize as many techniques as possible to increase the degree of
information and level of confidence of the results obtained. An-
other important factor is the availability of qualified analytical
laboratory service. The current turnaround from most labora-
tories can create a major problem for a project such as this, where
results are needed rapidly. Even premium rates for priority serv-
ice do not guarantee quick service. For projects with the potential
for litigation, it is advantageous to corroborate results with differ-
ent methodologies and different laboratories.
CONCLUSIONS
Monitoring for air toxics in the ambient air at hazardous waste
and other facilities is becoming more important and increasingly
necessary. Because the results of monitoring programs are being
used to demonstrate regulatory compliance and to resolve mat-
ters of litigation, they must be obtained in a rigorous and defen-
sible manner. Since no standardized methodology exists for devel-
oping and conducting ambient air toxics monitoring programs, an
approach has been presented in this paper.
The approach presented uses a decision tree to first identify
-------
program objectives and then to develop planning and implemen-
tation methods to achieve them. Defining the goals of the pro-
gram is seen as the most important part of the decision process.
Three primary goals are identified: (1) to support on-site health
and safety efforts, (2) to investigate ambient levels to which the
public may be exposed and (3) to determine a facility's contribu-
tion to ambient contaminant levels and regulatory compliance.
An integral part of the approach is the preparation of a site
specific monitoring plan encompassing the issues raised in the de-
cision process. Suggested contents of an air monitoring plan in-
clude site description, monitoring methods (for both air toxics
and meteorology) and QA/QC procedures. Regardless of the size
of the monitoring efforts, a monitoring plan of one form or an-
other should be prepared.
Several air sampling methodologies are suggested for sampling
particulate and gas phase air toxics. These methodologies have
been placed into three classifications based on sampling duration:
(1) instantaneous samples, (2) continuous samples and (3) inte-
grated samples. Depending on the application, any or all of these
sampling classifications may be employed.
It is generally felt that some meteorological monitoring should
be conducted concurrently with almost every air toxics monitor-
ing program, especially for wind direction and speed. The im-
portance of the meteorological monitoring will vary depending on
the goals of the air monitoring program.
The importance of QA/QC procedures for both field and ana-
lytical portions of the monitoring program cannot be overstated.
Use of rigid QA/QC procedures is the only way to assure de-
fensible air toxics data for regulatory compliance or litigation
purposes.
The methodology suggested for designing and conducting am-
bient monitoring at hazardous waste facilities can simplify the
process for obtaining air toxics data. However, the problems and
decisions faced are not simple ones. As evidenced in the case stud-
ies, a variety of applications exists for air toxic monitoring. Al-
though the decision process is essentially the same (decision tree)
from application to application, the nuances within each appli-
cation require the analyst to draw on past experience to develop
a program to meet the unique needs of each new project.
REFERENCES
1. Riggin, R.M., "Compendium of Methods for the Determination of
Toxic Organic Compounds in Ambient Air," EPA-600/4-84-041,
U.S. EPA, RTF, N.C., April 1984.
2. Riggin, R.M., "Technical Assistance Documents for Sampling and
Analysis of Toxic Organic Compounds in Ambient Air," EPA-600/
4-83-027, U.S. EPA, RTF, N.C., 1983.
3. Lewis, R.G., Martin, B.E., Sgontz, D.L. and Howes, J.E., "Meas-
urement of Fugitive Atmospheric Emissions of Polychlorinated Bi-
phenyls from Hazardous Waste Landfills," Environ. Sci. Tech., 19,
1985,986-991.
4. U.S. EPA, "Quality Assurance for Air Pollution Measurements
Systems," Vol. 1, Principles, EPA-600/9-76-005, Jan. 1976.
SAMPLING & MONITORING 157
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Low Level Groundwater Comtaination Investigation
At the Cleve Reber Superfund Site
Kenneth R. Miller, P.E.
ICF Technology Inc.
Pittsburgh, Pennsylvania
Jeffrey P. Hullinger, P.E.
CH2M HILL
Montgomery, Alabama
Stephen A. Gilrein
U.S. Environmental Protection Agency
Dallas, Texas
ABSTRACT
A groundwater investigation was performed at the Cleve Reber
Superfund Site to estimate the extent of hexachloro compound
migration from the site at the ng/1 (ppt) levels. This study of low
level groundwater contamination was performed due to the several
orders of magnitude difference between the normally used
laboratory detection limits and the very low health risk criteria for
the compounds of concern. Following the establishment of quality
assurance procedures for laboratory analyses, drilling and well in-
stallation and sampling, a series of "ultraclean" monitoring wells
was installed around the site and sampled.
The results of the study indicated that the site contributes very
little, if any, contamination to the groundwater. Additionally, the
investigation concluded that water samples obtained from wells
installed and sampled using standard techniques have falsely high
contaminant concentrations.
INTRODUCTION
The Contract Laboratory Program (CLP), which performs
chemical analysis of environmental samples for the Superfund pro-
gram, reports contract detection limits that are several orders of
magnitude greater than the 10"* lifetime excess cancer risk con-
centrations for numerous compounds on the Hazardous Substance
List (HSL). The 10"* lifetime excess cancer risk is the target
criterion generally used by the U.S. EPA to evaluate public health
risks resulting from a hazardous waste site. This variation between
the 10'6 lifetime cancer risk concentration (criterion concentra-
tion) and the detection limits reported by laboratories can lead to
difficulties in assessing site risks. When a compound is not found,
the assumption that the compound is not present can lead to
underestimation of site risks. Conversely, the conservative approach
of assuming the compound is present at the detection limit may
significantly overstate the site related risks.
The Cleve Reber Superfund Site Remedial Investigation and
Feasibility Study (Rl/FS) was completed using standard CLP detec-
tion limits for the compounds of concern. These detection limits
were up to three orders of magnitude greater lhan the criterion
concentration for the major site contaminant of concern, hex-
achlorobenzene (HCB). After the final Rl/FS was issued, the U.S.
EPA requested a one-time sampling of selected existing monitor-
ing wells surrounding the site. The samples were analyzed for HCB
using detection limits at or below the criterion concentration (21
ng/1 or ppt). The results of this sampling indicated that the con-
taminant of concern was present in a thin, water bearing zone
located approximately 40 ft below the ground surface. Positive
results were reported one to two orders of magnitude above the
criterion concentration. This original low concentration sampling
effort was conducted without the benefit of a detailed quality
assurance plan due to severe schedule restrictions. The U.S. EPA
then requested an extensive investigation of this shallow sand zone
to map a contaminant plume at ppt levels. This new investigation,
funded by the U.S. EPA, was to include a quality assurance plan
that considered the sensitivity of a ppt investigation. The one-time
low concentration sampling was important since it identified a
potential health risk previously unidentified. Although the sampling
was conducted without extensive quality assurance procedures, con-
fidence in the data existed because of good duplicate sample results,
and because residential well samples were clean, as expected.
SITE BACKGROUND
The Cleve Reber site is located in an undeveloped area between
Baton Rouge and New Orleans, Louisiana, about 2 mi east of (he
Mississippi River. There are approximately 25 homes within 0.5
mi of the site, with the nearest town (Sorrento, population 1,000)
being about 2 mi to the northeast. The area surrounding the site
has mixed uses. There is some agriculture within O.S mi of the site,
but most of the immediate surrounding area is undeveloped and
swampy land. There is a combination municipal/industrial land-
fill approximately O.S mi south of the site, and there is extensive
industrial development nearer the Mississippi River and along its
banks.
Before waste was disposed there, the site was used as a source
of borrow soil for the construction of nearby highway projects.
The resulting borrow pit was later used for municipal and industrial
wastes disposal. The pit area was about 600 ft by 1,400 ft. Test
borings drilled within the pit indicate that wastes were buried at
depths of about 6 to 20 ft. Disposal operations were halted in 1W4
prior to completely filling the pit. Consequently, a large pond
formed at the northern end of the site (Figure 1).
The site not only held state permits for the disposal of municipal
wastes, but also accepted industrial wastes. Reportedly, about 95*
of the waste disposed was municipal refuse. Records show that
industrial wastes were disposed on-site in drums and as bulk sludges
in segregated areas of the fill. The largest reported volume of in-
dustrial wastes disposed on-site was "hex pot" bottoms containmj
hexachlorobenzene (HCB), hexachlorobutadiene (HCBD) and
hexachloroethane (HCE). These chlorinated compounds are tne
site contaminants of primary concern due to their carcinogenic
nature. Although segregation of the wastes may have been
attempted during disposal activities, testing performed on leachw*
samples detected the presence of hazardous substances throughout
the waste pit, making the entire volume a hazardous matenal.
158 SAMPLING & MONITORING
-------
Figure 1
Cleve Reber Superfund Site Plan
Preliminary evaluations suggested that public health and environ-
mental hazards posed by the site were related primarily to surface
contacts and to groundwater. The remedial investigation (RI) con-
cluded that direct contact with contaminants on-site clearly posed
an unacceptable hazard. Contact with contaminants that may have
migrated off-site by surface water runoff was also a concern iden-
tified in the RI. Remediation of the surface contact related con-
tamination was called for in the RI/FS, including isolation of the
contaminants and prevention of migration by capping the site and
diverting surface water runoff. The presence of groundwater con-
tamination and the need for groundwater remediation were not
verified by the RI.
BACKGROUND GROUNDWATER DATA
The major fresh drinking water aquifers in the vicinity of the
site are the Norco and Gonzales Aquifers. The Norco Aquifer is
the major source of drinking water for residents near the site, while
the Gonzales Aquifer is a major regional source of water for both
private and industrial uses. The Norco Aquifer is located at a depth
of about 250 ft below ground surface at the site. The top of the
Gonzales Aquifer is reportedly about 500 ft below ground surface.
A generalized geologic section of the area is presented in Figure
2. The soils overlying the Norco and separating the Norco from
the Gonzales were reported to be low permeability, fine-grained
soils (clays and silts). Water levels in both aquifers are artesian
and are under free-flowing conditions for much of the year. Water
levels in these aquifers reportedly rise and fall with the Mississippi
River stage.
The RI concluded that the Norco and Gonzales Aquifers are not
likely to be contaminated by the site now or in the future. The
upward hydraulic gradient from these aquifers due to the artesian
conditions would cause contaminated groundwater to move up-
ward and away from these aquifers. The thick layers of low
permeability soils also provide a barrier to downward groundwater
flow. The density difference between the hexachloro compounds,
and in particular HCB and water, were considered but were not
considered great enough to overcome the hydraulic and physical
barriers to downward flow.
The RI also identified a sand zone at a depth of 40 ft below the
ground surface as shown on Figure 2. The sand zone is approxi-
mately 5 to 10 ft thick in the vicinity of the site. There are no
documented current uses of this groundwater source in the area,
although an onsite well is screened in this zone. This well reportedly
was used to produce water for use on-site. This zone could be used
as a source of small volumes of water, such as for domestic use.
The RI also indicated that the soils separating the 40-ft sand zone
and the waste pit were more permeable than previous investigations
had indicated. These soils are primarily fine-grained clays and silts
with laboratory permeabilities in the range of 10~7 to 10~9 cm/sec.
However, in-place test results were in the range of 10~3 to 1Q-5
cm/sec. It appears that secondary permeability features such as
root holes, fractures, slickensides and sand lenses, identified by
visually examining the soil samples, control overall soil mass
permeability. Laboratory tests do not accurately account for the
influence of these secondary features. Therefore, it was concluded
that some contamination could be expected to reach the 40-ft sand
zone.
DEPTH (FT.)
0
100
200
300
400
500
X
CLAY AND
=j] SANDY CLAY
SAND AND
SILTY SAND
CLAY AND
SILTY CLAY
SAND
(NORCO AQUIFER)
FINE GRAINED
SOILS
SAND
{GONZALES AQUIFER)
Figure 2
Generalized Geologic Section at the Cleve Rebel Site
Although the geologic and hydrogeologic findings suggested the
possibility of contaminant migration in shallow soil zones, samples
from wells screened in those zones gave negative results when sub-
mitted for standard CLP analyses. However, as Table 1 shows,
the detection limits for those standard analyses are up to orders
of magnitude higher than the health criterion concentration for
site contaminants. Therefore, the U.S. EPA requested a limited
sampling and testing program for the shallow monitoring wells in-
stalled during the RI using specially developed analyses to provide
detection at the criterion concentration of HCB (which is 21, ng/1).
In response to the U.S. EPA's request, five perimeter wells that
were used previously only as piezometers and were screened in the
40-ft sand zone were sampled. These samples were tested using
standard CLP detection limits for the complete HSL, and for hexa-
chlorobenzene using a detection limit of about 5 ng/1. Due to
schedule constraints, only HCB was analyzed at low detection levels
and no time was available to develop a quality assurance plan for
this sensitive work. Water samples from all of the wells showed
the presence of hexachlorobenzene at concentrations ranging from
about 0.2 to 7.4 /tg/1 (ppb). There was confidence in the low level
analytical procedures since split samples had similar results, and
residential well samples obtained were analyzed as being clean, as
anticipated. After receiving these results, the U.S. EPA requested
the development of a plan to determine the extent of groundwater
contamination in the 40-ft sand zone, with detection capability at
or below the criterion concentrations listed on Table 1.
SAMPLING & MONITORING 159
-------
Table 1
Comparison of CLP Contract Detection Limits
And Criterion Concentrations
HuadUonfcuttdim
OFIXUctltn
Tillltl fTTtll
20
30
90
Crlt«rl(ii
0.021
0.450
3.400
•Qrltwrlcn in thl» CM I* 10~* «n:im llfltlH cwnr riik in UM of •
drinkirg Mtor KffQy with th« lisud coitjaimit uimiLnticn.
INVESTIGATION PLANNING
Objectives
The major objective of the study was to verify the presence of
hexachloro waste contaminants in shallow groundwatcr in the site
vicinity. Results of previous analyses from samplings of standard
PVC monitoring wells were positive at concentrations above the
health risk criteria contamination. The zone in which these positive
results were detected was the thin sandy layer approximately 40
ft below the ground surface. The investigation focused on that
layer. Another objective of the study was to help the U.S. EPA
evaluate whether similar low-level groundwater contamination
studies might be feasible for other sites. Technical feasibility and
cost were to be evaluated at the completion of the investigation.
Documentation was therefore extensive.
Well Locations
Existing data for the site suggested that little gradient existed
in the shallow groundwater near the site, except for a general gra-
dient away from the site due to leachate mounding within the waste
pit itself. Consequently, there was no reason to concentrate the
monitoring in any direction from the site. Wells were planned in
equidistant locations (concentric rings) from the site center. Each
ring was planned to comprise six wells, equally spaced in plain view
on the ring.
One of the contamination avoidance measures was to drill and
sample wells in an order of least-contaminated to most-
contaminated. The first ring of wells was to be about 0.5 mi from
the center of the site, since at this distance the groundwater was
expected to be clean. The next ring was expected to be moved in-
ward, to perhaps 0.25 mi of the site center, unless positive analytical
results were received from samples from the first ring of wells. Deci-
sions on the location of the additional well ring(s) proceeded qukkly
to avoid downtime in the field. This meant that the laboratory had
to provide results within 48 hr of their receipt of the samples.
In addition to the monitoring wells located on the rings surroun-
ding the site, the study also included the installation of wells adja-
cent to existing monitoring wells screened in the 40-ft sand layer.
The existing wells that were sampled subsequent to the Rl were
constructed of PVC pipe using only standard decontamination and
drilling procedures. Since special techniques were planned to
prepare the wells for sampling and analysis for low levels of con-
tamination data, it was proposed that two "ultra-clean" wells
(described in Well Installation Techniques section) be installed ad-
jacent to two previously installed PVC wells. These wells would
be simultaneously sampled and the analytical results compared to
estimate the effects of drilling, development techniques and well
materials on low-level analytical results.
WELL INSTALLATION TECHNIQUE
Drilling was performed using dry augers, rather than the wash
technique typical in south Louisiana. The auger technique intro-
duces no external fluid into the borehole, and was expected to pro-
vide a leaner hole. An oversized surface hole was bored with
separate equipment to avoid introducing surface soil contamina-
tion into the well hole. This initial hole then was cased off as a
safeguard.
Although the auger drilling specification was a simple one, it
was difficult to fulfill, since drillers in south Louisiana prefer to
use wash techniques. The heavy clays which predominate in the
region are very stiff and plastic and place great torque demand!
on the drilling rigs using auger methods.
Procedures used for decontamination downhole drilling tools
and equipment included the following:
Scrubbing with potable water to remove accumulated mud
Rinsing with kerosene
Rinsing with hexane
Scrubbing with trisodium phosphate
Cleaning with high pressure steam
Stainless steel well casing was used for well construction since
the contaminants of concern might be expected to be in PVC. The
rigorous steam cleaning specificiations led to concerns that Teflon
casings would deform and Teflon's higher cost was not warranted
since no inorganic contaminants were of concern.
Glass beads were used as the gravel pack medium to avoid arti-
fact contamination. This was a field change, since rinse samples
of the same used for the first few wells in this study proved to be
contaminated with HCB at unacceptably high levels.
Rigorous decontamination procedures were followed for well
materials also. Also casing and screens were washed first with
acetone to remove paint and markings. They were then steam
cleaned.
Once tools, equipment, well casing and screen were decon-
taminated, they were wrapped in clean polyethylene sheeting until
they were used. Equipment which fell to the ground or which
became soiled in any way was decontaminated again before use.
Drill crew members changed coveralls and gloves between drilling
the borehole and installing well materials.
A series of rinse samples was collected periodically for analysis,
to evaluate decontamination effectiveness. These rinse samples were
collected from augers, drill rods, well casings, screens, surface
casing and gravel pack material (first sand; later glass beads). The
decontamination water also was sampled and analyzed.
Well Development and Sampling Methods
Once the wells were installed, special well development and
sampling techniques were needed to avoid introducing external con-
tamination. The only pieces of equipment to contact the well water
were decontaminated stainless sted bailers with teflon check valves
and a short length of hose for the development pump. The bailers
and check valves were decontaminated in a laboratory by solvent
and distilled water washing and baking in an oven at a temperature
of 392 °F for 1 hr. The decontaminated equipment was wrapped
in aluminum foil until use.
Development of the wells was by surface mounted centrifugal
pump, with the intake hose connected to a bailer lowered to the
bottom of the well. A high volume of water was flushed from each
well at high flow and high turbulence. The purpose of this tur-
bulence was to encourage sediments to flush completely out of the
well. Since HCB and the other contaminants of concern have high
octanol-water partition coefficients, they have an affinity for sedi-
ment over water. For this reason, removal of sediment was
especially critical. The high development flow also was expected
to flush any residual external contamination from the well casing
and allow a representative sample of groundwater to be obtained.
To sample each well, a bailer was attached to a decontaminated
stainless steel cable and the bailer was raised and lowered using
a downrigger reel (heavy-duty fishing reel). The reel was mounted
on a stepladder over the top of the well. During the bailing pro-
cess, the bailer touched nothing except the cable, well water and
the inside of the casing. The bailer was not allowed to be com-
pletely submerged, so the cable would not become wet.
Only one member of the sampling team (with dean gloves) was
allowed to handle the bailer itself. If the gloves touched anything
other than the bailer, new gloves were put on before proceeding.
In order to estimate the effectiveness of the bailer and other
equipment decontamination procedures, a series of rinsate samples
was planned. This included rinsate samples from bailers, stainless
160 SAMPLING & MONITORING
-------
steel cables, the downriggers and decontamination fluid containers.
Laboratory Methods
West Coast Analytical Services (WCAS), the laboratory selected
to perform the analytical work, performed the testing at reduced
detection limits and provided results within 48 hr after receiving
the samples. The fast turnaround was needed to properly locate
additional monitoring wells (i.e., further or closer to the site).
U.S. EPA Method 612 for Gas Chromatographic Analysis of
Chlorinated Hydrocarbons was modified to reach the required
detection limits. The Method Detection Limit (MDL) of Method
612 for hexachlorobenzene is 50 ng/1, although CLP and standard
laboratory analyses typically report detection limits of 20,000 ng/1
(20 ng/1). WCAS had to reduce its MDL one order of magnitude
(10 times) to achieve a MDL of 5 ng/1 for HCB and similar com-
pounds. Modification in Method 612 to achieve this reduction
included doubling sample size from 1 to 21 and concentrating the
sample to 2 ml rather than the usual 10 ml.
Validation of the above revised analytical method included:
• Analysis of six distilled water replicates (same source) spiked at
20 ng/I to estimate relative standard deviation (RSD), percent
recovery and MDL
• Analysis of six replicate field samples with low levels of con-
taminants to estimate RSD and MDL
• Analysis of six replicate field samples spiked with twice the
background levels to estimate percent recovery and RSD
In addition to the quality assurance procedures required by
Method 612, two additional procedures were followed. The
laboratory performed a daily mid-range calibration at an HCB con-
centration of less than 100 ng/1 and a weekly 5 point calibration
with at least one calibration point at less than 20 ng/1.
IMPLEMENTATION PROBLEMS/FIELD CHANGES
For the most part, the planned program and procedures were
implemented in the field and required no significant changes.
Necessary changes were due primarily to encountering contamina-
tion at unexpected concentrations or locations. These sources and
resultant changes included:
• Rinsate samples of the sand pack material indicated the presence
of hexachloro compounds. The natural sand material was
replaced by sterile glass beads. The beads were shown to be essen-
tially free of hexachloro compounds by rinsate sample analyses.
• Initially, kerosene was used as the decontamination solvent for
well casings and drilling tools. However, sources of kerosene
that were used for decontamination were contaminated with
hexachloro compounds in the range of 20 ^gle. After this
discovery, kerosene was no longer used for the decontamination
of drilling equipment.
• The first decontamination water source was contaminated with
low levels (hundreds of ng/1) of hexachloro compounds at con-
centrations greater than 100 ng/1. Several sources were analyzed
and rejected before a clean decontamination water source was
found.
We originally planned that only decontaminated stainless steel
bailers would be in contact with water during development. The
hose between the bailer and the pump was to remain above the
water within the well. During development of the first well, it
became apparent that the flow of water using this scheme was too
slow to lift the heavy sediments from the screened area of the wells.
After this discovery, decontaminated pump intake hoses were
allowed to contact the well water. The intake end of the bailers
was placed into the sediments at the bottom of the wells so that
the sediment at the base of the wells could be withdrawn directly.
This led to more rapid and more complete development and rinsing
of the wells.
In addition to the above procedural changes, the schedule
changed greatly from the plans. Decontamination procedures for
equipment and materials for each 40-ft deep well took 8 hr initially,
decreasing to about 6 hr once the drilling crews became familiar
with procedures. Adding to the time required to perform the sen-
sitive decontamination procedures was the time required to scrub
the sticky clays from the equipment between the drilling of suc-
cessive wells. Also, due to the extreme care being taken to purge
and sample the wells, a two-man crew could sample only two wells
per day compared to the anticipated four wells per day.
RESULTS OF INVESTIGATION
Laboratory Results
In general, the WCAS was able to achieve QA criteria throughout
the program. One problem did arise with reported concentrations
of the target compounds in laboratory blanks. Normally, if the
concentration of a compound in a sample is less than five times
the compound's concentration reported in the laboratory blank,
the sample results are rejected for that compound. This criterion
was exceeded numerous times during the investigation.
One approach considered for data use was to simply report
results as being above or below the criterion concentration (for
HCB, 21 ng/1). Below that concentration, it would be assumed
that site-related contamination was absent. This approach was re-
jected, since it did not take actual experimental error into account.
As an alternative to this approach, laboratory results, including
blank, rinsate and duplicate sample results, provided a reasonable
idea as to what measured baseline level of contamination could
be considered as suggestive of real groundwater contamination and
which could not. Observed bailer blank concentrations were com-
pared to well-casing rinse and gravel-pack rinse results; the highest
of these was selected as the baseline for HCB or other con-
taminants. Therefore, results were evaluated with this baseline con-
cept in mind. This was true even though the baseline concentra-
tion changed during the study.
Another problem resulted from a low concentration carryover
contamination between samples. Midway through the investigation,
a sample was obtained from an on-site well that had shown only
low levels of contamination when analyzed previously. During this
investigation, however, the sample concentrations were: HCE:
3,400,000 ng/1, HCBD: 1,300,000 ng/1 and HCB: 110,000 ng/1.
These concentrations saturated the GC column and laboratory test
equipment and considerable effort was required to clean all the
equipment so it could be used again.
The analyses performed following this sample, including
laboratory and field blanks, reported elevated levels of contam-
ination. The first field blank following the contaminated sample
detected HCB at a concentration of 150 ng/1 while the first
laboratory blank detected HCB at 13 ng/1. The concentrations of
contaminants reported in the blanks fell gradually, with the final
field blank having an HCB concentration of 7 ng/1 and the final
laboratory blank having an HCB concentration of 2 ng/1. These
blank concentrations elevated the baseline against which sample
results were compared.
Confidence in data quality was enhanced by splits of selected
samples analyzed by another laboratory under contract to poten-
tially responsible party (PRP) industries. This laboratory did not
analyze the highly contaminated sample, and thus had no carryover
problem. The carryover problem was shown to be minor con-
sidering the laboratory split data and therefore the confidence in
the data remained high.
Groundwater Contamination
Ten "ultra-clean" monitoring wells were installed around the
site. As planned, the first ring of wells was installed 0.5 mi from
the site. Due to property restrictions, however, only five wells were
installed on this ring instead of the planned six. Water samples
from these wells showed very low (less than 21 ng/1) concentrations
of hexachloro compounds; for this reason, the second ring of wells
was installed adjacent to the site boundary. Five wells were installed
on the second ring which was not circular but instead followed the
site boundary. (Figure 3).
SAMPLING & MONITORING 161
-------
LINE or nmr WILLS
(APMOX v, wu nan m>
STATE NOHWUV TO
•TULUCH MAO
Figure 3
Monitoring Well Plan—Location or Sampling Wells
All samples collected from ultraclean wells had reported concen-
trations of less than the criterion of 21 ng/1, except one sample
collected form well P7 and one analysis of a sample from well P8.
These were samples collected at nearly the same time as the highly
contaminated sample referred to elsewhere in this paper. Although
P9 is downgradient from the site, a second sample from it had a
reported HCB concentration of only 12 ng/1. Table 2 shows all
results for samples from ultraclean wells.
It is likely that some or perhaps all of the contamination
measured in the shallow groundwater water samples was not site-
related. Hydrogeologic data obtained during this investigation indi-
cated that the effects of on-site leachate mounding were less than
originally anticipated. Water flow in the 40-ft zone appears not
to oscillate but to flow continuously to the east. For this reason,
the wells located west of the site should not be contaminated due
to the Cleve Reber site. The samples from these wells had reported
hexachlorobenzene concentrations in the range of 10 ng/1.
Since analysis of samples from the ultraclean wells installed west
of the site reported concentrations of HCB of about 10 ng/1, we
concluded that either the sand zone has been contaminated by hexa-
chlorobenzene from other sources (apparently unlikely) or that the
reported concentrations are false positives due to experimental er-
ror. In either case, the site is contributing very little, if any, con-
tamination to the 40 ft sand zone.
Well Construction Comparison
Two monitoring wells were installed using ultraclean installa-
tion techniques adjacent to wells previously installed during the
Rl. The previously installed welk were constructed using PVC pipe,
wash boring methods and a non-tested source for decontamination
and drilling water. These wells also supplied samples subjected to
the initial low level analyses. Positive results from those analyses
were the driving force for this investigation. The new ultraclean
wells were constructed using stainless pipe and screen, dry auger
drilling methods nd strict decontamination procedures. Paired PVC
and ultraclean wells were sampled simultaneously using identical
sampling techniques as outlined in this paper to assess the difference
in water quality results between adjacent wells. The results of the
samples are presented on Table 3. while the locations of the wells
are shown on Figure 3.
Table 2
Groundwaler Quality Results
40-Fl Sand Zone
Htll Mo.
Hell Type
P-l Ultraclean
P-2 Ultraclean
P-3 Ultraclean
P-4 Ultraclean
P-5 Ultraclean
P-6 Ultraclean
P-7 Ultraclean
P-fl Ultraclean
P-t (rwanple) Ultraclean
P-9 Ultraclean
P-10 Ultraclean
PVC
W-12 PVC
W-14 PVC
H-16 PVC
USX
NO
ND
ND
ND
ND
ND
2
260
3
16
3
42
ND
ND
ND
H03J
ND
ND
ND
ND
ND
ND
3
470
6
70
11
400
140
20
62
OSS
14
10
10
10
7
13
30
120
12
20
13
490
1100
140
100
Several samples from wells immediately adjacent to the site (P6
through P10) had higher reported concentrations of hexachloro
compounds than similar results from the more distant wells (PI
through P5), especially for HCE and HCBO. Whether this reflects
true contamination in shallow groundwater near the site or rather
a bias effect due to accumulation of contamination in laboratory
or field equipment is open to question, since reported concen-
trations in both laboratory and field blanks became greater as the
study proceeded. Re-sampling of all ultraclean wells in random
order may be the best way to resolve this question.
Results for samples from PVC wells installed during the RI are
presented in Table 2. The difference in results when compared to
samples from the ultraclean wells is obvious. The specific source(s)
of artifact contaminants in the RI well samples could not be deter-
mined. Drilling method, well materials and decontamination proce-
dures all may contribute to downhole contamination. Earlier
contaminant migration assessments based on ultra-sensitive
analyses on samples from these wells were inaccurate.
Table 3
Comparison of Well Installation
Techniques and Materials
Well
Pair
Hell
No.
Investigation
Irstalled
Uaticns
W-14
P-6
W-10
P-9
RI
Low level
RI
Inw level
ND
ND
42
16
20
ND
400
70
140
13
490
20
Concentrations (ng/1)
The difference in results is obvious between the PVC wells
installed during the RI and the ultraclean wells installed during
the low level investigation; the results clearly demonstrate the
problem with normal drilling and well installation practices for this
type of investigation. The specific sources) of contaminants in the
Rl well samples could not be determined. The drilling method, well
materials, sampling techniques and decontamination procedures
all may contribute to well sample contamination. Contamination
assessments performed using the ng/1 level analyses for HCB from
the RI wells were inaccurate.
Well Development and Flushing Effects
As discussed previously, the hexachloro contaminants of con-
cern in this study have high octanol-water partition coefficients
and can be expected to attach preferentially to sediments rather
than stay in solution. Consequently, it was realized that effective
development of the wells (to flush out sediment remaining from
drilling activities) was especially important in this low level study
of groundwater contaminants. Several of the existing wells sampled
were not extensively developed during the RI in an attempt to
minimize the effects on the in-place permeability of the soils
adjacent to the well. These wells were redeveloped during this in-
vestigation and sampled.
162 SAMPLING & MONITORING
-------
Two ultraclean wells and two RI wells were sampled several times
over an extended period of time to determine the effect of total
purge flow on measured sample contaminant concentrations. The
results of these samplings are presented on Table 4. Since all wells
were purged of at least five well volumes of water before each
sampling, the progressively lower sample results suggest a signi-
ficant effect of total purge flow on reported contaminant concen-
tration. The results are more dramatic for the RI wells, but are
significant even for the ultraclean wells. Although the effects of
time and increased purge volume cannot be accurately separated
they are expected to be negligible, since degradation of these com-
pounds in groundwater should be very slow.
CONCLUSIONS
As a result of this careful study of the Cleve Reber Site to detect
Table 4
Water Quality Results After Multiple Well Samplings
Investigation
Program Installed
Date
Sanpled
Hexachlorobenzene
Cone, frotl
W-l
H-14
p-1
P-8
RI
RI
Low Level
Low Level
1/22
1/30
2/6
4/19 (1 IM)
4/19 (4 IM)
1/20
2/4
1/29
2/6
4/9
4/11
4/20
1,900
800
600
650
220
440
140
IB
14
9
120
12
low level hexachloro chemicals, we concluded that:
• It is possible to perform an investigation to measure low con-
centrations of contaminants in groundwater and obtain useable
results. The cost-effectiveness of the methods is questionable and
the procedures are time intensive.
• Laboratory QA can be maintained to obtain usable results at
low ng/1 concentrations. However, a rigorous program of
laboratory blanks and method validation is necessary to assess
the extent of laboratory-related contamination.
• The installation of wells to measure contaminants at ng/1 levels
is possible, but requires rigorous procedures including:
— Extensive decontamination
— Careful drilling with continuous professional oversight
— Testing all well materials at the criterion concentration
• Samples suspected as being highly contaminated should not be
analyzed using the equipment utilized for low concentration
analyses without first screening on less sensitive equipment.
Samples should be collected and analyzed in the order of least-
expectation to greatest-expectation that contaminants are present.
• Large numbers of field QA samples (blanks, duplicates and
spikes) are especially desirable to improve confidence in low level
contaminant data. Additionally, replicate wells (two or more
wells installed near each other and screened in the same interval)
should be installed to quantify well related random contamina-
tion; if possible.
• Contamination related to well materials, drilling methods, decon-
tamination fluids and sampling methods may become especially
significant during an investigation of low level contaminant con-
centration. Fluid and rinsate samples must be sampled rigorously
to determine whether these sources of contamination are compro-
mising the investigation. The investigator must be willing to
change materials and fluids to eliminate identified contamina-
tion sources.
Extensive well development (high turbulence and high total
purged volume of water) is essential for accurate measurement of
groundwater quality, especially in low level investigations.
SAMPLING & MONITORING 163
-------
A Cost-Saving Statistically Based Screening
Technique for Focused Sampling
Of a Lead-Contaminated Site
Anthony F. Moscati, Jr., D. Env.
Eric M. Hediger
WAPORA, Inc.
Rosslyn, Virginia
M. Jay Rupp
Martin Marietta Corporation
Baltimore, Maryland
ABSTRACT
High concentrations of lead in soils along an abandoned rail-
road line prompted a remedial investigation to characterize the
extent of contamination across a 7-acre site. Contamination was
thought to be spotty across the site reflecting its past use in bat-
tery recycling operations at discrete locations. A screening tech-
nique was employed to delineate the more highly contaminated
areas by testing a statistically determined minimum number of
random samples from each of seven discrete site areas. The ap-
proach not only quickly identified those site areas which would
require more extensive grid sampling, but also provided a statis-
tically defensible basis for excluding other site areas from further
consideration, thus saving the cost of additional sample collection
and analysis. The reduction in the number of samples collected in
"clean" areas of the site ranged from 45 to 60%.
INTRODUCTION
In December 1985, WAPORA surveyed the extent of reported
lead contamination of railroad property in Troy, Ohio, formerly
owned by the Cleveland, Cincinnati, Chicago and St. Louis
Railway (CCC & St. L). Until 1978 a portion of this property was
utilized for automobile and industrial battery salvage operations.
Batteries to be salvaged at a nearby concern were received at a
common railroad loading dock, off-loaded and trucked to the
salvage site. Reclaimed lead was packed in 55-gal drums, trucked
to the loading dock and shipped to processing facilities. During
these activities, materials containing lead were spilled in the
loading dock area and the general environs of the former depot.
Lead concentrations in excess of 380,000 ppm were measured at
the site in an initial investigation by the U.S. EPA's TAT contrac-
tor. Interviews with area residents, many of whose residences
abutted the railroad property, provided a vague picture of the
physical layout of the battery recycling operation. More accurate
delineation of the areas of contamination prior to sampling was
precluded by a fire after the recycling operation ceased. The fire
destroyed structures that might have provided further clues and
caused major portions of the site to be regraded, thus obliterating
other indicators. An overview of the site showing the seven areas of
interest (including north/south components) is provided in Fig. 1.
THE SAMPLING APPROACH
The description by area residents of the lead recycling opera-
tions suggested that some portions of the site, notably areas 1
and 3, might contain no lead. There were several reasons for
thinking so:
• Major elements of the recycling operation had been located in
areas 2 North, 4 North and, as was eventually discovered,
area 5
• Lead compounds left to weather at a site are usually highly in-
soluble and are often not susceptible to wind dispersion over
large distances
• No visual observations of lead deposition were made in areas 1
and 3, in contrast to the other areas
It was felt that a preliminary screening of the site using a
statistically defensible approach might eliminate areas 1 and 3
from the more exhaustive grid sampling necessary in the other
areas, thus conserving the private client's sampling budget.
The method ultimately selected considered all points within a
sampling areas to be at equal risk for lead contamination. For
each of the seven areas flanking the CCC & St. L railroad
mainline, a sampling grid was selected with grid size based on the
likelihood of gross contamination (i.e., smaller grid sizes in areas
known to be used for battery recycling or scrap loading). The in-
tersections of the grid lines (nodes) were each identified by a
number. The total number of grid nodes within an area became
the sample population at risk, referred to as N. At this point, the
statistical approach begins to deviate from straightforward grid
sampling.
To minimize the sampling burden, a subgroup, n, is selected to
have a high probability to include sample locations of maximum
concentration (highest 10%). The probability of missing locations
within the highest 10% concentration levels becomes a. The cor-
rect sample size for subgroup n is expressed by the following-
equation:
Po(N, T, n) = a
(D
where:
N -
n =
total number of grid intersections for area of concern
subgroup sample size
r = percentage of maximum concentration (highest 10%)
a = the probability of missing locations within maximum
concentration percentage, T (0.05)
The solutions for various sample populations, concentration
subgroups and allowed probability have been previously pub-
lished. For this project, the most stringent criteria were utilized as
presented in Table 1.
164 SAMPLING & MONITORING
-------
Figure 1
Lead Sampling Project: Location of Sampling Areas 1-5
Table 1
Sample Size for Top 10%
(T = 0.1), confidence = 0.95 and a = 0.5 (use n = N if N < 11)
Total locations
N = 19-21 22-24 25-27 28-31 32-35 36-41 42-50 >50
Required no. of
sample points
(n) = 15 16 17 18 19 20 21 29
With the total potential sampling locations (N) and the number
of sample points (n) established, random selection for the identi-
fier numbers of the actual sampling points was accomplished by
computer. Utilization of computerized random selection
eliminated both individual and site bias.
APPLICATION OF THE METHOD
The statistical methodology was employed independently on
each of the seven site areas. In areas 1 through 4 North and
South, the sampling results corroborated the statements of area
residents:
• Areas 1 and 3 generally were indicated to be clean areas in
both memory and analytical result. Only 5 out of 38 samples
showed lead contamination at levels from 500 ppm to 1,000
ppm. Subsequent sampling of the two areas as a check on the
approach revealed no pattern of more extensive contamination
in either area.
• Areas 2 North and South showed evidence of moderate con-
tamination. In area 2 North, for example, 5 of 21 samples
showed contamination at levels in excess of 500 ppm; 3 of the
samples tested in excess of 1,000 ppm. Again, subsequent
sampling and analysis confirmed a pattern of limited contam-
ination as shown in Fig. 2.
• Areas 4 North and South were indicated to be among the most
heavily contaminated in both interview and analytical result. In
Area 4 North, for example, about half of the samples ob-
tained in the initial pass through the area tested at levels in ex-
cess of 1,000 ppm with one as high as 6,000 ppm.
• Area 5 was a surprise. Interviews with residents had suggested
that Area 5 would look more like Areas 1 and 3 (i.e., lightly, if
at all, contaminated). However, 10 of the 29 samples analyzed
showed levels over 500 ppm with 6 at levels greater than 1,000
ppm. One sample tested at 24,000 ppm. These results indicated
Area 5 should undergo more intensive sampling, a process
that confirmed a pattern of heavy contamination of the area.
Fig. 3 shows the pattern of contamination eventually re-
vealed and highlights the samples selected statistically for an-
alysis.
CONCLUSIONS
Application of the statistical sampling screen to the site facili-
tated delineation of the overall picture of site contamination in a
rapid and cost-effective manner. Areas, such as Areas 1 and 3,
where light contamination was suggested by the results of the
statistical sampling approach were confirmed through subsequent
sampling to be, indeed, only lightly contaminated with lead.
These areas required far less excavation than the others. Using the
statistical approach in Areas 1 and 3 in lieu of full grid sampling,
cut sampling and analysis costs by 45% and 60% respectively.
The benefit of this approach, however, was perhaps best indi-
cated in its detection of Area 5 as an area of potentially serious
contamination, an indication confirmed by subsequent detailed
sampling. Prior to sampling, anecdotal evidence had suggested
that Area 5 could be largely ignored.
SAMPLING & MONITORING 165
-------
LEGEND
Pb Conc.(ppm)
CD 0-800
•I 801- 1000
• > 1000
^Drilling Raluaal
CD] Nol Analyiad
DaptM II.)
§0-0.8
y ;
6 ample No.
Railroad
ONID:IO'l20'
'Statistically determined
sampling location
N = 49
n=21
Figure 2
Lead Sampling Project: Area 2 North
In summary, the method has several features that make its ap-
plication at a site useful for broad-brush delineation of gross con-
tamination:
• Samples are taken at standard grid nodes so that all data ob-
tained remains useful even if full grid sampling is subsequently
implemented (i.e., neither data nor dollars are wasted)
• Cost savings achieved over full grid sampling and analysis
of "clean" areas are in the ratio of N-n, a value ranging from
from about 21% to 50% for grids having up to 50 nodes and
increasing for higher numbers of grid nodes
LEGEND
Pb Conc.(ppf) 0«plM ll )
CD 0-500
•1501- 1000
•I >1000
^Drilling Rduial
[III Not Analyzed
0-0.S
00 1
t *
Sampla No.
— Railroad
GRID: 2«' « IB'
^Statistically determined
sampling location
N = 90
n=29
Figure 3
Lead Sampling Project: Area 5
• Laboratory turnaround time can be significantly shortened
due to the smaller number of samples required, thereby facili-
tating a (better informed) secondary sampling effort following
up on first phase results
• Different confidence levels for results can be obtained using
different numbers of samples
REFERENCES
Leidel, N., Busch, K. and Lynch. J., Occupational Exposure Sampling
Strategy Manual. U.S. Department of Health, Education and Welfare,
Cincinnati, OH, 1977.
Paizen, E., Modern Probability Theory and Its Application, John Wiley
& Sons, New York, NY, I960.
System Control, Inc. 1975. SCI Report #5119-1. Produced under Con-
tract No . CDC-99-74-75.
166 SAMPLING & MONITORING
-------
U.S. EPA Guidelines for
Risk Assessment
Peter W. Preuss, Ph.D.
Alan M. Ehrlich, Ph.D.
Kevin G. Garrahan, P.E.
U.S. Environmental Protection Agency
Office of Health and Environmental Assessment
Washington, D.C.
ABSTRACT
In recent years, the U.S. EPA has moved toward a risk assess-
ment/risk reduction framework to make regulatory decisions. The
Agency has taken a number of steps to assure the quality and con-
sistency of the risk assessment component of those decisions. The
first, and perhaps most important, is the development of Agency-
wide risk assessment guidelines. Five guidelines have been proposed
and are nearing the completion of the public- and peer-review pro-
cess. They are: carcinogenicity, mutagenicity, developmental tox-
icity, chemical mixtures and exposure. The provisions of the five
guidelines are discussed in the context of the four components of
risk assessment.
Other activities designed to assure quality and consisteny in risk
assessments, reduce uncertainty in risk assessment, ensure a more
efficient information exchange about risk and risk assessment and
develop the appropriate oversight mechanisms also are discussed.
These include additional guidelines, the Risk Assessment Forum,
risk assessment research, the Integrated Risk Information System,
the Hazard Assessment Notification System, and the Risk Assess-
ment Council.
INTRODUCTION
One of the U.S. EPA's key factors in developing a pollution
control strategy is evaluating scientific information to assess the
risk from an environmental insult or the degree that the risk may
be reduced under any particular control scenario. As a result, risk
assessment is increasingly important to the regulatory process. It
is clear that the distinction between risk assessment and other parts
of the regulatory decision process needs to be carefully and com-
prehensively defined. This regulatory decision process was basically
defined several years ago by the National Academy of Sciences
(NAS) and can include legal, economic, political and social factors
as part of the management of risks determined by the risk assess-
ment process (1) (Figure 1).
RISK ASSESSMENT
! "do MIAIUKIMINTI.
! IITIMATIO fXPOIUflEI.
! CHAUCTUIUT10M Of
i WUUTMNI
RISK MANAGEMENT
OtVELOPMI
HEOULATOH
T OPTION!
Figure 1
Elements of Risk Assessment and Risk Management
During the past decade, the U.S. EPA has moved vigoriously
to a risk assessment/risk management/risk reduction framework
for making regulatory decisions. As a consequence, the assurance
of quality and the consistency of assessments have become im-
portant Agency issues.
A number of steps have been taken to help achieve these goals
of quality and consistency; perhaps the most important step is the
development of Agencywide assessment guidelines. The U.S. EPA
had developed such guidelines in the past: carcinogenicity in 1976
and 1980, systemic toxicants and mutagenicity in 1980 and exposure
assessment in 1983 (2,3,4,5). In January, 1984, the U.S. EPA began
intensive work on six new or revised guidelines: carcinogenicity,
mutagenicity, reproductive toxicity (subdivided into individual
guidelines for developmental toxicity and male and female
reproductive toxicity), systemic toxicants (e.g., target organ toxi-
cants), chemical mixtures and exposure assessment 6.
The first stage for each guideline was the development of drafts
by Agency-wide work groups of scientists. These drafts then were
circulated to scientists from academia, other governmental agencies,
industry and public interest groups.
Using this procedure, five guidelines (carcinogenicity,
mutagenicity, developmental toxicity, chemical mixtures and ex-
posure) were proposed for public comment 7,8,9,10,11 After the
public comments were received, Agency staff evaluated the com-
ments, suggested revisions and sent the proposed guidelines and
the evaluation of comments to special review panels of the Science
Advisory Board (SAB). The review panels and the Executive Com-
mittee concurred on the guidelines subject to certain revisions and
subsequently concurred on the revisions12-13. The proposed risk
assessment guidelines are* in the final stages of review and clearance
and will, upon completion, be published in the Federal Register
14,15,16,17,18
The U.S. EPA's guidelines set forth internal Agency procedures
that will:
• Promote consistency across U.S. EPA risk assessments by
developing common approaches to risk assessment
• Promote the quality of the science underlying the U.S. EPA risk
assessments by using a consensus approach (discussed below)
where appropriate
• Clarify the U.S. EPA's approach to risk assessment by informing
the public and the regulated community about the process used
to evaluate scientific information
The guidelines are not regulations: in fact, they are intentionally
flexible to encourage the use of all data and the appropriate scien-
tific methods and judgments. The guidelines can, however, in-
fluence the regulatory process by:
• Making the U.S. EPA's risk assessments more consistent and
of higher technical quality
• Familiarizing risk assessors throughout the country with the U.S.
EPA's approach
• Making it possible for scientists to plan their experiments to
collect the information that U.S. EPA scientists would like to
have available when conducting a risk assessment
RISK ASSESSMENT/DECISION ANALYSIS 167
-------
Finally, these guidelines are intended to be evolving documents.
They are being updated, even now, as the science base relating to
risk assessment leads to new understanding of the effects of toxic
substances or to a reduction of the uncertainty inherent in the risk
assessment process.
General agreement on the need for risk assessment guidelines
does not exist. Some scientists have argued that articulation of
guidelines is inappropriate and that every situation should be
evaluated on a case-by-case basis. They believe that this case-by-
case approach is necessary because of the complexity of the scien-
tific issues and their concern that it is not easy to develop or follow
general rules. On the other hand, others prefer detailed guidelines
that take risk assessors through each step of the process and spell
out specific approaches or scientific conclusions. As in most
disagreements, there is a mddle group wishing to develop a general
logic for the kinds of information needed and to articulate ap-
propriate methods for assessment and evaluation. In this approach,
the guidelines are intended to be tools in the hands of skilled scien-
tists; they encourage the evaluation and use of all the available in-
formation on a case-by-case basis.
COMPONENTS OF RISK ASSESSMENT AND THEIR
RELATIONSHIP TO THE GUIDELINES
In discussing risk assessment and risk management, the NAS
divided the process of risk assessment into four components':
• Hazard Identification—the determination of whether a particular
chemical is or is not causally linked to particular health effects
• Dose-Response Assessment—the determination of the relation
between the magnitude of exposure and the probability of
occurrence of the health effects in question
• Exposure Assessment—the determination of the extent of human
exposure before or after application of regulatory controls
• Risk Characterization—the description of the nature and often
the magnitude of human risk, including attendant uncertainty
To the extent possible, the U.S. EPA's guidelines follow the
Academy's definitions. The following sections describe each in
greater detail and show how the guidelines relate to them.
HAZARD IDENTIFICATION
The hazard identification component of a risk assessment con-
sists of a review of relevant biological and chemical information
bearing on whether or not an agent may pose a specific hazard.
Sometimes, there is enough information available for the qualitative
evidence to be combined into a formal weight-of-evidence
determination.
For example, in the guidelines for carcinogen risk assess-
ment 7'14, the following information is evaluated to the extent that
it is available:
• Physical/chemical properties and routes and patterns of exposure
• Structure/activity relationships
• Metabolic and pharmacokinetic data
• The influence of other toxicologic effects
• Short-term tests
• Long-term animal studies
• Human studies
Once these data are reviewed, the animal and human data are
divided separately into groups by degree of evidence:
• Sufficient evidence of carcinogenicity
• Limited evidence of carcinogenicity
• Inadequate evidence
• No evidence of carcinogenicity
The animal and human evidence then are combined into a weight-
of-evidence classification scheme similar to the one developed by
the International Agency for Research on Cancer." This scheme
gives more weight to human evidence when it is available. The
scheme includes the following groups:
• Group A human carcinogen
• Group B probable human carcinogen
• Group C - possible human carcinogen
• Group D not class!ficiable as to human carcinogenicity
• Group E - evidence of non-carcinogenicity towards humans
To some degree, these are arbitrary divisions along a continuum;
therefore, categories should not be overinterpreted. The attached
matrix (Table I) shows how the human studies and long-term
animal studies are combined to derive the first approximation of
the overall weight-of-evidence classifications. Other types of
evidence then are used to adjust the first approximation upwards
or downwards as appropriate.
Table I
Illustrative Categorization of Evidence Based on Animal and Htuun
Data.14
HIHAK
EVIDENCE
SUFFICIENT
LWI HO
(Motown
HO 0»t»
evidence or
•0 CFftCT
ANINU EV1DEKC
SUFflCltKT LIMITED IMOEDlWTE MTA
A « « A
1) 11 11 II
12 C 0 D
W C 0 0
tt C 0 0
IVIBlfcci a
K) EFFECT
«
11
0
E
E
NOTE: The above assignment* «rc presented lot illustrative purposes. There may be ntuaca m
the classification of both animal UK! human data indicating thai different categoruauoftt Una
ihoK given in the (able should be assigned- Furthermore, these assignments are tentative and at)1
be modified by ancillary evidence. In Urn regard all relevant information should be cvatoaudig
determine if the designation of the overall weight of evident* needs to be modified- RdevM lac-
ion lo be included along with the tumor data from human and animal studies include flracurt-
activity relationships, short-term test findings, results of appropriate phyuolofkal. ^"it'Trri
and lexicological observations and comparative metabolism and pharmacofcineik studies. Theaanrt
of these findings may cause an adjustment of the overall categorization of the weight of enacaoe.
In the case of mutagenicity risk assessment,8'15 the goal is to
assess the likelihood that a particular chemical agent induces
heritable changes in DNA and the likelihood that the chemical will
interact with human germ cells.
Evidence that an agent induces heritable mutations in human
beings could be derived from epidemiologic data indicating a strong
association between chemical exposure and heritable effects. It is
difficult to obtain such data, however, because any particular muta-
tion is a rare event and only a small fraction of the estimated
thousands of human genes and conditions currently are useful as
markers in estimating mutation rates.
Therefore, in the absence of human epidemiologic data, it is
appropriate to rely on data from experimental animal systems so
long as the limitations of using surrogate and model systems are
clearly stated. The universality of DNA and the interest in the possi-
ble causal relationship between mutagenesis and cancer induction
are partly responsible for the development of a large number of
both in vitro and in vivo mutation tests which may be used to
evaluate the potential mutagenic activity of specific agents, the prac-
tical implication is that the available data for any set of chemicals
are extremely variable, thus precluding a precise scheme for classi-
fying chemicals as potential human germ-cell mutagens. A rank-
ordered scheme of categories of evidence hearing on potential
human germ-cell mutagenicity has evolved. The highest category
is reserved for human epidemiologic data, recognizing that no such
data currently are available. There are five other categories fin
descending order) based on the premise that greater weight is placed
on tests conducted in germ cells than in somatic cells, on tests per-
formed in vivo rather than in vitro, in eukaryotes rather than pro-
karyotes and in mammalian species rather than in submammalian
species. Additionally, there is a category for defining a non-
mutagen, and there is a category for insufficient information to
make a qualitative decision.
The specific statements of the eight categories are:
I. Positive data derived from human germ-cell mutagenicity
studies, when available, will constitute the highest level of
168 RISK ASSESSMEN/DECIS1ON ANALYSIS
-------
evidence for human mutagenicity
2. Valid positive results from studies on heritable mutational
events (of any kind) in mammalian germ cells
3. Valid positive results from mammalian germ-cell chromosome
aberration studies that do not include an intergeneration test
4. Sufficient evidence of a chemical's interaction with mam-
malian germ cells, together with valid positive mutagenicity
test results from two assay systems, at least one of which is
mammalian (in vitro or in vivo). The positive results may both
be for gene mutations or both for chromosome aberrations;
if one is for gene mutations and the other for chromosome
aberrations, both must be from mammalian systems
5. Suggestive evidence of a chemical's interaction with mam-
malian germ cells together with a valid positive mutagenicity
evidence from two assay systems as described under 4, above.
Alternatively, positive mutagenicity evidence of less strength
than defined under 4, above, when combined with sufficient
evidence for a chemical's interaction with mammalian germ
cells.
6. Positive mutagenicity test results of less strength than defined
under 4, combined with suggestive evidence for a chemical's
interaction with mammalian germ cells
7. Although definitive proof of non-mutagenicity is not possi-
ble, a chemical could be classified operationally as a non-
mutagen for human germ cells if it gives valid negative test
results for all end points of concern
8. Inadequate evidence bearing on either mutagenicity or
chemical interaction with mammalian germ cells
In the guidelines, developmental toxicity includes adverse effects
on the developing organism that may result from exposure prior
to conception (in either parent), during prenatal development or
postnatally to the time of sexual maturation9'16. The major
manifestations of developmental effects include death of the
developing organism, malformation, altered growth and functional
deficiency. The term teratogenicity refers primarily to malforma-
tions and is a subclass of developmental toxicity.
Short-term and in vitro tests, which frequently are used for
assessing risks from suspect carcinogens and mutagens, are not
apropriate approaches for assessing developmental toxicity because
the developing organism is such a complex system. Instead,
bioassays and human epidemiologic data are the primary sources
of information used. The primary biological assays involve treat-
ment of animals during organogenesis and evaluation of the off-
spring at term. These types of evaluations also may be done as
part of a multigeneration study.
The kinds of evaluations that are made in the U.S. EPA's hazard
identification/weight-of-evidence determination include, as with
all such evaluations:
• Quality of the date
• Resolving power of the studies; that is, consideration of the
significance of the studies as a function of the number of animals
or subjects
• Relevance of route and timing of exposure
• Appropriateness of dose selection
and, more specifically in the case of developmental toxicity, an
evaluation of the information for a series of end points that may
include:
• In the developing animal
— deaths
— structural abnormalities
— growth alterations
— functional deficiencies in the developing organism
• In the maternal animal
— fertility
— weight and weight gain
— clinical signs of toxicity
— specific target organ pathology and histopathology
In the case of chemical mixtures10-17, the U.S. EPA conducts
its hazard identification by considering the weights-of-evidence for
the mixture's component chemicals. Occasionally, and especially
for complex mixtures, the evidence for a health hazard comes
directly from studies on the mixture itself. Information on the mix-
ture itself, however, must be carefully reviewed for evidence of
masking of one toxic end point by another. For example, when
one of the component chemicals is a suspect carcinogen but the
data show marked toxicity in major organs (e.g., liver, kidney)
and no indication of cancer, there is the possibility that other toxic
effects may mask the evidence of carcinogenicity. The hazard
identification then would suggest no cancer risk at any dose when,
in fact, there could be significant risk of cancer at doses below
the threshold for systemic toxicity.
Exposure assessment usually is a separate step in the risk assess-
ment process; the exposure guidelines are discussed in a later section
of this document. For mixtures, however, the exposure informa-
tion must be considered to determine the chance that chemical in-
teractions in the environment could produce new chemicals, over
time or during transport, with different types of health hazards
resulting. This concept is discussed more fully in the next section.
DOSE-RESPONSE ASSESSMENT
Classically, there are two general approaches to dose-response
assessment depending on whether the health effects are threshold
or nonthreshold. For threshold effects, discussed later in this
section, the assessment estimates the point below which we do not
expect a significant adverse effect. For nonthreshold effects, an
attempt is made to extrapolate response data from doses in the
experimental range to response estimates in the dose ranges typical
of most environmental exposures. The largest number of such dose-
response extrapolations have been performed in the field of car-
cinogen risk assessment; therefore, the cancer guidelines give the
most detailed guidance on dose-response assessment7'14. These
guidelines include the kinds of evidence that should be used in the
dose-response evaluation, such as:
• If available, estimates based on human epidemiologic data are
preferred over estimates based on animal data.
• In the absence of appropriate human studies, data from animal
species that respond most like humans should be used.
• The biologically acceptable data set from long-term animal
studies showing the greatest sensitivity generally should be given
the greatest emphasis.
• Data from the exposure route of concern are preferred to data
from other exposure routes; if data from other exposure routes
are used, the considerations used in making route-to-route extra-
polations must be carefully described.
• When there are multiple tumor sites or multiple tumor types,
each showing significantly elevated tumor incidence, the total
estimate of carcinogenic risk is estimated by pooling, i.e., counting
the number of animals having one or more of the significant
tumors.
• Benign tumors generally should be combined with malignant
tumors for risk estimates.
Another major consideration is the choice of the particular
mathematical model used for low-dose extrapolation. Different
extrapolation models may fit the observed data reasonably well,
but may lead to large differences in the projected risk at low doses.
In keeping with the recommendations of the Office of Science and
Technology Policy,20 the Agency will review each assessment as
to the evidence on cancer mechanisms and other biological or
statistical evidence that indicates the biological suitability of a par-
ticular extrapolation model. A rationale will be included to justify
the use of the chosen model. In the absence of adequate informa-
tion to the contrary, the linearized multistage procedure will be
employed. The linearized multistage procedure is recognized as
leading to a plausible upper limit to the risk that is consistent with
some proposed mechanisms of carcinogenesis.
Additional issues are species- and route-extrapolation of the
doses. Currently, the U.S. EPA adjusts animal doses by the ratio
of animal-to-human surface areas. The evidence in support of this
approach is not strong, and research is in progress to improve the
method. Route extrapolation is used when the only available data
RISK ASSESSMENT/DECISION ANALYSIS 169
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are for a route different from the route of concern.
In the present case of mutagenicity risk assessment8-15, dose-
response assessments can only be performed using data on ger-
minal mutations induced in intact mammals. The morphological
specific locus and biochemical specific locus assays can provide
data on the frequencies of recessive mutations, and data on
heritable chromosome damage can be obtained from the heritable
translocation test. As in carcinogen risk assessment, the Agency
will strive to use the most appropriate extrapolation models for
risk analysis and will be guided by available data and mechanistic
considerations in this selection. However, it is anticipated that for
tests involving germ cells of whole mammals, few dose points will
be available to define dose-response functions, and a linear extra-
polation will therefore be used. The Agency has recognized that
pioneering work in the field of molecular dosimetry ultimately may
lead to useful extrapolation models.
The other major approach to dose-response assessment concerns
effects which the Agency refers to as systemic toxicants or non-
carcinogenic health effects (see below). Although this particular
area is not yet covered by guidelines (they are still being developed),
it is appropriate to discuss the general approach. The Agency
usually calculates what is called Reference Dose (RfD), that is, the
dose below which we do not expect a significant risk of adverse
effects. The reference does is related to the more familiar concept
of the Acceptable Daily Intake (ADI), but strives to remove the
elements of risk management from the process. At present, the
U.S. EPA is not sure at which point above the RfD there will be
a significant adverse health effect. The dose-response evaluation
is done in the following way. The literature is examined to deter-
mine both the critical toxic effect (that is, the adverse effect that
first appears in the dose scale as the dose is increased) and the
highest dose at which the effect does not occur (often called the
highest No-Observed-Adverse-Effect-Level or NOAEL). This
NOAEL is divided by an uncertainty factor which generally ranges
from 10 to 1,000; the uncertainty factor is composed of a series
of factors, each representing a specific area of uncertainty inherent
in the data available.
The RfD calculation is a generic calculation for most toxicants
considered to have thresholds. In addition, much work is being
conducted in an attempt to develop more quantitative approaches
for dose-response assessment for reproductive and developmental
toxicants both within and outside of the U.S. EPA.
The dose-response procedures described in the chemical mixtures
guidelines are a bit different10'17 In this case, guidance is provided
to combine several different types of information on the mixture
of concern as well as on the mixture's components. If dose-response
data are available for the mixture itself, such data are used and
other Agency risk assessment procedures would apply to the mix-
ture as a whole. If data are not available on the specific mixture,
it may be appropriate to infer information from sufficiently similar
mixtures. When neither is available, the guidelines suggest using
what is called dose or response addition, appropriately modified
if interactions between components (such as synergism) can be
quantified. When interactions cannot be quantified and when the
component chemicals are lexicologically similar, strict dose addi-
tion is used. For most threshold pollutants this means dividing each
estimated intake level by its RfD and summing each of these quo-
tients to calculate a hazard index. When the hazard index is much
greater than one, a significant risk might be expected. When the
hazard index is near one, each case needs to be considered
individually.
For carcinogens and for dissimilar systemic toxicants that have
dose-response data, response addition is used so that, at typical
environmental levels, the excess risks for each component chemical
are summed to reach an overall risk estimate. Again, interactions
need to be considered, and we must recognize the added uncer-
tainty in the assessment. The Agency intends to investigate this
and other problems involving mixtures that contain carcinogens
over the next few years.
EXPOSURE ASSESSMENT
From the titles of the various risk assessment guidelines, it is
clear that four of the five relate to health effects; in those cases,
which have been presented previously, discussions of hazard iden-
tification and dose-response assessment are appropriate. In con-
trast only, one guideline discusses exposure assessment.
The Proposed Guidelines for Exposure Assessment" and the
Guidelines for Estimating Exposures" provide a procedural
framework on how best to estimate the degree of human contact
to a chemical. The major areas to be evaluated when estimating
exposures are:
• Source assessment—a characterization of the sources of con-
tamination
• Pathways and fate analysis—a description of how a contami-
nant may transport from the source to the potentially exposed
population
• Estimation of environmental concentration—an estimate using
monitoring data and/or modeling of contamination levels away
from one source where the potentially exposed population it
located
• Population analysis—a description of the size, location and
habits of potentially exposed human and environmental receptorc
• Integrated exposure analysis—the calculation of exposure levels
and an evaluation of uncertainty
An integrated exposure assessment quantifies the contact of an
exposed population to the substance under investigation via all
routes of exposure and all pathways from the sources to the ex-
posed individuals.
Generally, exposure estimates may be presented by expressing
the magnitude and duration of an individual event of exposure or
by expressing potential lifetime exposure. For example, evaluations
of acute or subacute effects, such as developmental effects, would
use the magnitude of exposure per event or several events over a
short period of time. On the other hand, assessments of carcino-
genic risk often consider the daily average exposure calculated over
a lifetime. The nature of the toxic effect being evaluated in the
risk assessment will determine the appropriate length of exposure
presented.
For most risk assessments involving chronic exposure, exposure
(mg/kg/day) is calculated as a dose averaged over the body weight
(kg) and lifetime (days):
Average Daily
Lifetime Exposure
Total Dose
(I)
Body Weight x Lifetime
The total dose (mg) can be expanded as follows:
Total Contaminant Contact Exposure Absorption^)
Dose = Concentration x Rate x Duration x Fraction
The four parameters in equation (2) are defined as follows:
• Contaminant concentration represents the concentration of the
contaminant in the medium (air, food, soil, etc.) contacting the
body; typical units are mass/volume or mass/mass.
• Contact rate is the rate at which the medium contacts the body
(through inhalation, ingestion or dermal contact); typical units
are mass/time or, for dermal contact, volume/surface area.
• Exposure duration is the length of time for contact with the
contaminated.
• Absorption fraction is the effective portion of total contami-
nant contacting and entering the body. Entering the body means
that the contaminant crosses one of the three exchange mem-
branes: alveolar membrane, gastrointestinal tract or skin.
The six factors given in equations (1) and (2) must be known
(or estimated) in order to estimate exposure. Research is in pro-
gress to better define how to estimate each of these factors for
humans as well as test animals.
RISK CHARACTERIZATION
In our guidelines, the risk characterization step is a summing
discussion in which information is put together in a useful way.
This means that the risk characterization contains not only a risk
170 RISK ASSESSMENT/DECISION ANALYSIS
-------
estimate for a specific exposure, but also a cogent summary of the
biological information, the assumptions used and their limitations
and a discussion of both qualitative and quantitative uncertain-
ties in the risk assessment.
In the case of cancer, mutagenicity and chemical mixtures
guidelines7'8'10'14'15'17, the risk characterization specifically consists
of the dose-response extrapolation information as well as the
associated weight-of-evidence determination from the scale or table
contained in the guidelines. For mixtures10'17, the weight-of-
evidence covers three areas: health effects information, toxic in-
teractions and exposure estimates.
In the case of the exposure assessment guidelines, a specific
mathematical technique has been developed to assess
uncertainty11'18. In this case, the probability distributions
estimated for the uncertainty around each compartment in the
calculation are entered into a computer program, and the proba-
bility distribution of the results of the exposure assessment can then
be calculated or estimated.
SYSTEMIC TOXICANTS
The last of the six original areas of guidelines development is
for systemic toxicants. Guidelines have not yet been prepared
because it is difficult to reach consensus for such a broad area.
The U.S. EPA essentially includes chemicals causing a variety of
health effects other than cancer, mutagenicity and specific acute
effects under the umbrella of systemic toxicants. This umbrella
clearly covers many end points and many different target organs
that could be considered for any one chemical.
In the absence of consensus procedures, each Program Office
at the U.S. EPA has approached the problem in different ways21.
Examples include evaluating a specific adverse health effect rather
than determining the critical health effect (the adverse health effect
occurring at the lowest dose and assessing risk for less than lifetime
exposure rather than determining a lifetime chronic Acceptable Dai-
ly Intake (ADI) or Reference Dose (RfD). In addition, Program
Offices have used different approaches for dealing with uncertainty.
Some offices estimate a lifetime chronic RfD based on uncertainty
factors tied to the available information and then establish criteria
based on that RfD. Some offices calculate a Margin of Safety
between the highest No-Observed-Adverse-Effect-Level (NOAEL)
of the critical effect and the estimated exposure and then evaluate
that margin specifically in terms of the chemical of interest and
its expected exposure pattern. Some offices estimate an appropriate
degree of protection on a case-by-case basis, using their best
technical and scientific judgment. Finally, some programs have
developed their own quantitative techniques for extrapolating or
interpolating across data gaps; few of these have yet gained general
acceptance within the Agency.
The guidelines development effort has postponed the Agency
achieving consensus on the entire list. Generic issues resolved in
this RfD review process will then form the basis for the guidelines
on systemic toxicants.
OTHER GUIDELINES PROJECTS
The Science Advisory Board (SAB) reviewed the proposed
guidelines and suggested the development of two additional
documents: guidelines for making and using environmental
measurements in exposure assessments, and a technical support
document for the guidelines on chemical mixtures. Work on those
projects is under way. In addition, a document is being developed
to focus on areas in need of research in developmental toxicology.
Work also is continuing on two other guidelines, one for the
Assessment of Risk to the Male Reproductive System and the other
for the Assessment of Risk to the Female Reproductive System.
In addition, Agency staff is working on guidelines for the assess-
ment of systemic toxicants and is planning guidelines for the assess-
ment of ecological risk and the appropriate use of metabolism and
pharmacokinetic data and models.
RISK ASSESSMENT FORUM
Risk assessment guidelines are only one tool used to make
decisions. The guidelines, therefore, are only one part of the pro-
cedures to make the Agency's decisions more consistent and
reliable. Another mechanism is the Risk Assessment Forum. For
any one issue, the available information may lead to differing
scientific interpretations; these differences need to be resolved. In
addition, there may be areas that the guidelines presently do not
cover but which need immediate or short-term resolution.
Finally, as scientific theories develop and change or as experimen-
tal techniques and risk assessment assumptions change, there needs
to be a way to augment or amend the Agency's risk assessment
policies. The Agency, therefore, decided to establish a standing
group of senior scientists who would meet regularly to provide a
"forum" for those kinds of discussions and decisions6'22. This
new organization is not intended to be involved in routine quality
assurance of risk assessments; it will only become involved where
significant scientific uncertainties or science policy issues need
resolution.
The Forum assists the U.S. EPA's risk assessment process in
several ways:
It analyzes scientific information and science policy issues for use
in Agency risk assessment
• It develops risk assessment guidance not covered by the guidelines
• It recommends revisions to the guidelines whenever such revisions
appear to be necessary
• It mediates inter-office differences on risk assessment issues
• It recommends appropriate research to reduce uncertainties in
risk assessment
REDUCING UNCERTAINTIES
One of the critical needs in risk assessment is reducing the uncer-
tainty of the estimates. The U.S. EPA is undertaking several
activities to do that. First, the Agency has planned three workshops.
One, a "Consensus Workshop on the Relationship of Maternal
and Developmental Toxicity" was held recently to address issues
of interpretation of data in the area of developmental toxicity when
toxicity to the maternal animal may also be apparent23
Another workshop to be held this fall is on the use of pharma-
cokinetic models in risk assessment. The goal of this workshop
is to identify the basis on which these models are formulated and
the assumptions and data that are necessary for their use. This
workshop will address the practical application of pharmacokinetic
principles and models to improve risk assessment.
Finally, there will be a workshop this fall on cancer research
needs to help the Agency identify the key areas of risk assessment
research for carcinogenicity and to establish a list of priorities for
that research. The authors anticipate that these latter two
workshops will be the first of a fairly extensive series on workshops
in these areas.
OTHER ACTIVITIES
The U.S. EPA was one of the pioneers in developing and
adopting risk assessment methods. For the first 10 yrs, this meant
developing the techniques, applying them and then attempting to
reach consensus about their appropriate use. That effort has
culminated in the proposed publication of the five guidelines and
in the continued plans for guideline development and risk assess-
ment research.
It is now appropriate to consolidate that effort by ensuring a
more efficient information exchange about risk and risk assess-
ment and by developing the oversight mechanisms to ensure con-
sistency and high technical quality in the Agency's risk assessments.
One area of concern is quality assurance of the hazard and risk
evaluations developed within various Program Offices; for
example, the work of the RfD review group referred to earlier.
A review group has been working since early 1985, and its first
group of RfDs is nearing approval for inclusion in Agency infor-
mation systems (see discussion below). A similar review process
is being established for carcinogen risk estimates.
RISK ASSESSMENT/DECISION ANALYSIS 171
-------
Another area of concern is the development of appropriate in-
formation exchanges about risk assessment activities in the U.S.
EPA in order to identify the hazard assessment activities under
way within the Agency and prevent possible duplication, to increase
the awareness of ongoing activities of interest to various Program
Offices and to improve Hazard Assessment Notification System
in which Program and Regional Offices will list all hazard
assessments in a data base and report on work that is under way
or anticipated.
Another such Agency-wide activity is the Integrated Risk Infor-
mation System (IRIS). One of the many problems encountered by
risk assessors both inside and outside of the U.S. EPA is obtaining
coherent information about existing Agency risk conclusions useful
for formulating risk assessments. The results of carcinogen
bioassays, dose-response calculations, NOAELS, RfDs and other
parameters for a large number of chemicals exist, but this infor-
mation has never been integrated into an easily accessible,
centralized information base.
Information in IRIS will be organized in a readily accessible elec-
tronic mail system on a chemical-by-chemical basis. Information
will be provided by four continuing efforts, each of which will be
reviewed periodically for consistency and quality prior to entry into
the system. As a chemical-based system IRIS will collect informa-
tion for a compound and construct a file in which all numbers Tit
into a particular format.
Information provided by the four continuing efforts, will
periodically supply updated assessments and information to the
central IRIS management unit. One effort will contribute reviewed
RfDs, while a second will do the same for cancer risk estimates.
The third component will list acute hazard information that the
Agency has recently published24 and the fourth will provide risk
management numbers Agency-wide (Reportable Quantities,
National Ambient Air Quality Standards, Water Quality Criteria,
Maximuim Contaminant Levels, etc.). Information from these four
projects will be merged to produce a file consisting of a series of
chemical-specific documents. The user then will be able to call up
a chemical by name and review all of the pertinent U.S. EPA
summary material.
Other computer-related projects include the development of
toxicity data bases. The furthest along is "Studies on Toxicity
Applicable to Risk Assessment." This data base is unique because
it contains toxicity data for each dose group and includes programs
for calculating and presenting the data in human equivalent terms
by using the extrapolation models and time-weighted-averaging
methods discussed previously. A second project is a mixtures data
base, currently containing summary information about more than
1,200 studies on toxic interactions such as synergism and an-
tagonism. Both data bases are being prepared so that they can be
accessible to the public to further the improvement of risk assess-
ment methodology.
Finally, the Agency has established the Risk Assessment Coun-
cil to provide oversight for the development, review and imple-
mentation of U.S. EPA policy related to risk assessment.
CONCLUSION
Risk assessment at the U.S. EPA has evolved from an art
developed by a small group of people discussing primarily cancer
to a general analytic and decision tool used by many people in many
programs across the Agency. Furthermore, many of the U.S. EP A's
statutes are now predicted on a risk reduction basis, which requires
more and better health risk and exposure analyses. Since the
possibility of overlapping and conflicting analyses exists, a larger
Agency program is necessary to review risk assessments in general,
to oversee the process and to develop more detailed guidelines. The
structures to assure this quality and technical consistency are now
evolving within the Agency.
Therefore, as risk assessment becomes more sophisticated, as
more risk assessments are performed and as the need for assurance
of quality and consistency is increased, the Agency will develop
guidelines for more end points, add more detail to existing
guidelines, strengthen the management procedures to resolve scien-
tific disputes, publicize those resolutions, and maintain the appro-
priate degree of oversight. This process will result in the develop-
ment of better risk assessments with less overall uncertainty and,
ultimately, better protection of public health.
DISCLAIMER
The views expressed in this paper are those of the authors and
do not necessarily reflect the views or policies of the U.S. EPA.
REFERENCES
I. National Research Council, Risk Assessment in the Federal Govern-
ment: Managing the Process, National Academy Press, Washington,
D.C.. 1983.
2. U.S. EPA, "Interim procedures and guidelines for health risk and
economic impact assessments of suspect carcinogens," Federal Register
41 (1976) 21402.
3. U.S. EPA, "Mutagcniciiy risk assessment: proposed guidelines,"
Federal Register 45 (1980) 79317.
4. U.S. EPA, "Ambient water quality criteria documents: notice of
availability," Federal Register 45:(I980) 79317.
5. U.S. EPA, "Guidance for performing exposure assessments," on-
published draft, available from Science Advisory Board, U.S. EPA,
Washington, DC (1983).
6. U.S. EPA, "Risk Assessment and Management: Framework for Deci-
sion Making," Report *EPA-600/9-85-002, available from Office of
Policy, Planning, and Evaluation. U.S. EPA, Washington, DC (1984).
7. U.S. EPA, "Proposed guidelines for carcinogen risk assessment,"
Federal Register 49: (1984) 46294.
8. U.S. EPA, "Proposed guidelines for mutagenicily risk assessment,"
Federal Register 49 (1984) 46314
9. U.S. EPA, Proposed guidelines for the health assessment of suspect
development toxicants," Federal Register 49 (1984) 46324
10. U.S. EPA, "Proposed guidelines for the health risk assessment of
chemical mixtures," Federal Register SO' (1985) 1170.
11. U.S. EPA. "Proposed guidelines for the exposure assessment," Fedatl
Register 49 (1984) 46304.
12. Nelson N., letter to Lee M. Thomas, Administrator, U.S. EPA, Match
14, 1986, available from Science Advisory Board, U.S. EPA,
Washington, DC
13. Nelson N., letter to Lee M. Thomas, Administrator. U.S. EPA, March
14. 1986. available from Science Advisory Board, U.S. EPA,
Washington. DC
14. U.S. EPA, "Guidelines for carcinogen risk assessment," in preparation.
15. U.S. EPA. "Guidelines for mutagenicily risk assessment," in
preparation.
16. U.S. EPA, "Guidelines for the health assessment of suspect
developmental toxicants," in preparation.
17. U.S. EPA, "Guidelines for the health risk assessment of chemical ma-
tures," in preparation.
18. U.S. EPA, "Guidelines for estimating exposures," in preparation.
19. International Agency for Research on Cancer, IARCMonographs™
the Evaluation of the Carcinogenic Risk of Chemicals to Humans, Sup-
plement 4, Lyon, France, 1982.
20. U .S. Office of Science and Technology Policy, "Chemical caranogpis:
a review of the science and its associated principles," Federal Register
50: (1985) 10372.
21. Anderson E.L., Ehrlich A.M., "New risk assessment initiatives in
EPA," Toxicol. Ind. Health 1 (1985): 7.
22. Goldstein B., "Strengthening the assessment of risk," EPA Journal
10{1984):5.
23. Kimmel G.L., Kimmel C.A., Francis E., Pmc of the Consensus
Workshop on the Relationship of Maternal and Developmental Tox-
icity, May 1986, Fund. Apl. Toxicol., to be published.
24. U.S. EPA, "Chemical Emergency Preparedness Program: tatenm
Guidance, Revision 1, 9223.0-1 A," Nov. 1985.
172 RISK ASSESSMENT/DECISION ANALYSIS
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A Comparative Evaluation of Methods for
Determining Alternative Concentration Limits
Gaynor W. Dawson
C. Joseph English
ICF Northwest
Richland, Washington
ABSTRACT
Alternative concentration limits (ACLs) provide a means of
establishing cleanup levels for site restoration. Derivation of an
ACL requires determination of two numbers, an effects criterion
(EC) and an exposure factor (EF). The EC represents the con-
centration at the point of exposure and reflects the contaminant's
intrinsic toxicity. The EF represents the degree to which the con-
taminant concentration will be reduced in moving from the source
to the point of exposure (i.e., the ratio of source concentration
to exposure concentration). The EF is often a composite factor
combining dilution, dispersion, degradation and attenuation on
soils and aquifer media. The product of the EC and EF represents
the maximum permissible concentration at the source area or the
allowable cleanup level.
This paper provides a comparative discussion of methods
which can be employed to derive values for EF. Specific ap-
proaches include analysis of monitoring data, the use of tracers
and the use of mathematical models. The advantages, disadvan-
tages and costs of each approach are discussed, and general guide-
lines are offered to select methods on a site-specific basis. Key
determinants in the selection of an approach include the exis-
tence and quality of a monitoring well system, the physical/chem-
ical properties of the contaminants and the complexity of the
groundwater system at the site.
INTRODUCTION
The passage of CERCLA, promulgation of the National Con-
tingency Plan (NCP) and amendments to RCRA in 1984 have
raised considerable debate over the issue of "How Clean is
Clean" with respect to corrective and remedial actions. While
the U.S. EPA has not chosen to promulgate specific standards
for site cleanup residuals, its growing use of risk assessment and
risk management has provided the framework for a definitive
approach on a site-specific basis. In particular, the agency has
espoused the concepts of acceptable risk and probable exposure
levels based on fate and transport considerations between the
source and the receptor.
The use of risk assessment for selecting restoration levels was
illustrated early in the CERCLA program with the Exposure-
Response Analysis method.' In this approach, acceptable site re-
sidual levels are derived from a health-based concentration goal.
The former is larger than the latter in recognition of dilution and
attenuation which will occur during transit. The ratio of the
former to the latter is a quantitative measure of dilution and
attenuation factors for a given site. The U.S. EPA similarly
acknowledges dilution and attenuation by allowing ACLs for site
restoration levels which are higher than, but based on, health cri-
teria, i.e., restoration levels are derived after allowance for con-
centration reduction during transport. As with the Exposure-
Response Analysis method, the development of safe ACL values
depends on the successful selection of the dilution/attenuation
or exposure factor and the health-based effects criteria.
Development of defensible effects criteria for a number of
pollutants based on lexicological data presently is being con-
ducted by the U.S. EPA. Determination of the former for site-
specific cases is the subject of the following discussion, which
characterizes the relative merits and deficiencies associated with
different methods currently available. For purposes of organiza-
tion, alternative methods have been grouped into three categories:
passive empirical (monitoring data), active empirical (tracers)
and theoretical (modeling).
PASSIVE EMPIRICAL METHODS
Passive methods involve the analysis of monitoring data to de-
termine the degree of concentration reduction that will occur
between the point of release and the point of exposure. In the
ideal case, monitoring wells already would exist at the contam-
inated site and at several points downgradient, including the
compliance point. Concentrations of the contaminant of interest
would be measured at each well. The ratio of the source concen-
tration and compliance point concentration represents the atten-
uation undergone by the contaminant while in transit. As such,
the ratio constitutes the desired EF.
Clearly, the monitoring approach represents an accurate and
inexpensive means of determining an EF under favorable circum-
stances. If monitoring wells are already in place, the incremental
costs amount to those for analyses (which are likely to be required
anyway). Many times, however, circumstances are not ideal.
Common difficulties include those stemming from improper well
location and inadequate plume development. These difficulties
are discussed below.
Improper Well Location
If wells are not available at the source and at the point of com-
pliance, the EF cannot be directly calculated. Two potential solu-
tions are available. The most straightforward involves comple-
tion of monitoring wells at the required points. However, this
approach can be expensive. For sites which are poorly character-
ized, a number of wells may have to be installed to accurately
define the source of contamination, both areally and vertically.
In cases where the plume is broad or multiple potable wells need
to be protected, a number of compliance point wells may be re-
quired. This approach is contingent on an adequate knowledge of
the geohydrologic setting to designate the compliance points for
protection of all threatened receptors. The approach offers the
advantage of providing wells which subsequently can be used to
RISK ASSESSMENT/DECISION ANALYSIS 173
-------
monitor the adequacy of corrective or remedial actions.
The second approach can be implemented if there are a num-
ber of monitoring wells proximate to and surrounding the points
of interest. In this case, geostatistical methods are used to esti-
mate the contaminant concentrations and uncertainty levels near
the source and points of compliance. Mapping the concentra-
tions provides a means of determining the probable range of con-
centrations which would be measured in a properly located mon-
itoring well at each point of interest. If applicable, this approach
is often less costly than construction of additional wells and has
the added advantage of quantifying uncertainty. Even if addi-
tional wells are required, geostatistical analysis of existing mon-
itoring data is often valuable for determining new well locations.
Inadequate Plume Development
Direct use of monitoring data will not be possible if the con-
taminant of interest has not reached the compliance point or has
not reached steady-state conditions between the source and the
compliance point. In either case, comparison of monitoring data
would produce an inordinately high EF. The first condition can
be identified easily when the contaminant of interest does not
appear in samples from the compliance point. The second con-
dition may not be as easy to identify without time sequence data
establishing a constant ratio between well head concentrations
over a period of a year or more. Once again, some knowledge of
the geohydrologic setting is desirable to help establish the likeli-
hood that the plume has reached steady state or to identify the
required period of observation to make that determination.
If plume development is inadequate for all species in a dis-
charge, the monitoring approach will not work in the short term.
However, if plume development is complete for constituents
other than those of concern, alternatives are available. For in-
stance, if a contaminant of like adsorption and degradation po-
tential has reached a steady state, it can be used to develop the
EF by analogy. More commonly, if a conservative, mobile species
has reached steady state, concentration data for it can be used to
quantify the contribution of dilution and dispersion to the overall
EF. If adsorption and degradation prolperties for the contam-
inant of interest are well characterized, EF can be increased ac-
cordingly with simple algorithms. Chloride is a particularly good
conservative species for this purpose. Under proper circum-
stances, sulfate, nitrate, sodium, bromide or fluoride also may
be employed. The analog approach is inexpensive to perform, but
requires the presence of the conservative species in the overall
plume at levels distinguishable from background.
ACTIVE EMPIRICAL METHODS
Active approaches to determining an I-1- parallel the passive
options but involve the intentional release of a tracer material to
delineate groundwater travel times and paths. Most active sys-
tems require the same network of release and monitoring wells as
passive systems and, therefore, cncounicr the same costs and
drawbacks related to improper well location. The unique feature
of active systems, the introduction of the tracer, offers both ad-
vantages and disadvantages to the overall activity.
The advantage of an active tracer stems from the analyst's
ability to select a tracer with specific transport properties. Ideal-
ly, one would specify a nontoxic tracer with attenuation and de-
gradation properties identical to those of the contaminant of
concern. Recent work with fluorocarbons has been very success-
ful in developing a variety of tracers with a spectrum of attenua-
tion properties.
The disadvantage of active tracers is the need to wait for the
tracer to move from the source to the monitoring well. In slowly
moving groundwaters, the time delay will be larger than waiting
for the contaminant to reach the monitoring wells. In such a
case, passive monitoring becomes more economical. To circum-
vent the time problem, nonattenuating tracers can be introduced
to elucidate dilution. Absorption, degradation and other atten-
uation mechanisms then can be accounted for with simple algo-
rithms. Various agents are available as conservative tracers (i.e.,
tritium, chlorides and nonreactive fluorocarbons). Additionally,
monitoring well locations can be moved backward to accelerate
tracer tests. The data obtained then can be extrapolated forward
to the compliance point. This accommodation adds uncertainty
with respect to the linearity of the dilution phenomenon from the
monitoring point on out to the compliance point.
An interesting modification to direct tracing approaches in-
volves the use of a tracer which can be remotely monitored with-
out wells. Electromagnetic induction (EMI) measures in situ con-
ductivity in the earth. When intervening clay layers or metallic
objects do not interfere, remotely-sensed conductivity can map
the existence of saline plumes in groundwater or of freshwater
in a groundwater brine. Therefore, if groundwater is low in con-
ductivity, a brine solution (e.g., sodium chloride) could be added
at the source and monitored remotely. When mapped, periodic
measurements would provide a good indication of plume speed,
dilution and plume size over time. Freshwater could be injected
into a brine system and similarly tracked. In both cases, the trac-
ers (brine or freshwater) would be conservative and factors other
than dilution and dispersion would have to be considered sep-
arately.
The problems associated with use of tracers, namely the neces-
sary time delays, can be avoided with proper planning in RCRA
programs. In particular, if waste materials are intentionally
spiked with conservative tracers at known levels prior to disposal,
existing monitoring wells will provide an early warning that
corrective action is needed as well as the necessary data to calcu-
late the dilution portion of the EF. If the tracer were carefully
selected, it also could reduce monitoring costs significantly.
THEORETICAL METHODS
Theoretical methods for establishing exposure factors can be
classed under the general term mathematical modeling. While the
word modeling often raises images of sophisticated numerical
constructs and high costs, it is important to note that models can
consist of a wide variety of tools that simulate reality. They may
be as simple as a single equation or as complex as a massive com-
puter program. The level of complexity should be dictated by the
requirements of the problem.
In general, mathematical models can be grouped into three
broad categories: simple algorithms, analytical models and
numerical models. Algorithms may define a single phenomenon
such as one-dimensional flow under set conditions of head, con-
ductivity and porosity. Analytical models generally accommodate
a number of phenomena under prescribed boundary conditions
and homogeneous properties. Numerical models are the most
flexible of the three and, therefore, can accommodate hetero-
geneity and complex boundary conditions. Costs and input data
requirements increase with the level of sophistication. Similarly,
within each group there are different levels of flexibility and
sophistication available at increasing levels of cost.
The advantage offered by modeling is the ability to predict
forward without the time delays inherent in monitoring or tracer
approaches. Modeling also may be possible without construction
of new monitoring wells. However, well data are required for the
necessary inputs to the modeling process. Sites with no existing
wells will require well construction to obtain the data needed to
calibrate the model. In this regard, theoretical and empirical
methods will incur similar costs. Modeling may reduce the nunv
174 RISK ASSESSMENT/DECISION ANALYSIS
-------
ber of wells required and, more importantly, can assist in de-
termining whether existing data represent a steady-state plume
development or a transient state. Perhaps the greatest advantage
of modeling is the ability to evaluate the utility of proposed
corrective/remedial actions as well as develop exposure factors
for an array of compliance points. When tracers or monitored
constituents have attenuation properties different from those of
the contaminant of concern, the use of algorithms to accom-
modate those differences constitutes modeling.
Attenuate
'• Contaminant
I
No
Fully Developed f
I
!• There Time
Available For
Tracer Study?
Figure 1
Decision Tree for Developing an Exposure Factor to Derive
Alternative Concentration Limits
In addition to groundwater transport models, geochemical
models also may be useful for establishing ACLs, particularly
with inorganic contaminants. The value of geochemical models
arises for contaminants whose concentrations in groundwater are
controlled by geochemical reactions, particularly dissolution/
precipitation reactions. In cases where contaminant concentra-
tions are solubility limited, there is no fixed relation between the
concentrations at the source and compliance point. Evaluation
of the geochemistry at the site is necessary to determine whether
the effects criterion will be exceeded.
The disadvantages of modeling arise from input data and re-
source needs. Since these needs are commensurate with the com-
plexity of the model applied, they will vary between sites. There is
also a perception problem associated with models. With strictly
empirical approaches, one need only assure the quality of the
data collected. With modeling, it is necessary to verify the model
itself as well as the input data. Because models are often very
technical, their use and interpretation requires special training. In
turn, they often are viewed with suspicion by nonmodelers.
If modeling is selected as the best approach for deriving an
exposure factor, the analyst still may be faced with the need to
select a specific computer code. The U.S. EPA recently has devel-
oped model selection criteria for use in conducting exposure
assessments. The guidelines accompanying these criteria will be
of great value to less experienced modelers.
CONCLUSIONS
As indicated in the previous sections, there are a number of
approaches which can be taken to select an exposure factor dur-
ing the derivation of an ACL. Each approach has advantages
and disadvantages based on the conditions at the site of concern
and the problem set at hand. In general, the analyst should seek
to select the most accurate, least costly approach feasible for a
given site. Because the relative accuracy and costs will vary among
the alternatives, selection is accomplished best using a logic tree
evaluation, as illustrated in Figure 1.
REFERENCES
1. Dawson, G.W. and Sanning, D., "Exposure-Response Analysis for
Setting Site Restoration Criteria." Proc. of the National Conference
on Management of Uncontrolled Hazardous Waste Sites, Washing-
ton, DC, 1982, 386-389.
RISK ASSESSMENT/DECISION ANALYSIS 175
-------
Risk Assessment for Underground Storage Tanks
Captain Dennis J. Foth, P.E.
United States Air Force
Directorate of Environmental Planning
Tyndall AFB, Florida
ABSTRACT
Risk is an issue of growing importance in both public and pri-
vate sectors. Each has been faced with the task of examining the
environmental and public health risks associated with under-
ground storage tanks. Such risk assessments usually end with a
decision as to what action, if any, should be taken to mitigate
existing or potential problems. These decisions are based on many
quantitative and nonquantitative variables. This paper describes
one methodology involved in conducting risk assessment.
The process starts by compiling factual information relevant to
an underground tank system. This process is called risk analysis.
In the next step, risk assessment, the completeness of the infor-
mation, its uncertainty and its applicability to the system and
location are put into perspective through a numerical rating meth-
odology. The objective of the assessment is to arrive at a numer-
ical rating for each system. Using this numerical rating, the de-
cision maker can develop a relative ranking of systems. Ideally,
the rank ordering of the systems will correlate closely with the
actual health and ecological risks. The key is to manage these risks
at a minimum cost while protecting the environment. Because re-
sources are limited, the ranking of systems will aid the decision
maker in setting priorities to address those problems that offer
the greatest reduction in risk for the money spent.
INTRODUCTION
Cleanup of a leaking tank system can cost millions of dollars.
Because of the potential for huge direct and indirect costs of a
leaking underground storage tank, it is imperative to have a pro-
gram to assess risks involved with operating and maintaining such
a system. With the increase in awareness of environmental sen-
sitivity in recent years, the field of Risk Assessment has taken on
increased importance. In the most general sense, Risk Assessment
involves the evaluation of the potential impact of an underground
storage tank leak. The negative impacts due to a storage loss
might include not only environmental damage, but also economic
loss and legal liability. Such liabilities can be caused by on-site
soil or groundwater contamination, off-site contaminant migra-
tion, contamination of drinking water supplies or generation of
potentially explosive vapors, just to mention a few possibilities.
By conducting an early risk assessment, a company can imple-
ment preventative measures which are generally less costly than
after-the-fact cleanup procedures. Clearly, the assessment of risk
prior to incidents can be a valuable planning tool.
Risk Assessment can be performed in many different formats.
One method of evaluating risk is based on Risk Assessment and
Management (RAM) which is patterned after the Air Force Haz-
ard Assessment Rating Methodology (HARM) system. The objec-
tive of RAM is to assess any risks involved with current and past
operations that fall under the Underground Storage Tank (UST)
program. RAM will provide a relative ranking of tank systems
as to their potential for leaking. It also will provide indicators
for early detection and remedial action before a leak occurs. If a
leak does occur, RAM will allow one to detect and intercept con-
taminants before damage is caused.
RAM is designed to quantify the risk of contamination through
the application of a numerical rating. This is done to enable one
to rank tank systems in a relative manner as to potential for leak-
ing and subsequent potential for contaminating the environment,
particularly water resources. Each assessment considers multiple
parameters in order to rate a specific site. The standard meth-
odology is designed to yield consistent results so that each site can
be rated accurately against the rest. An accurate definition of the
tank system and surrounding environment at a site is critical to
Risk Assessment and Management Rating. By ranking the system,
the manager will have a good indication as to which system should
be given priority attention.
There will not be sufficient funds available to take care of all
potential problems at the same time. Thus, it is prudent to have a
risk assessment management program to prioritize sites and to ex-
pend funds on those sites where the greatest savings through leak
prevention and detection can be achieved.
DESCRIPTION OF MODEL
The rating model described in this paper is referred to as the
Risk Assessment and Management Rating Methodology (RAM).
Like other site ranking models, the RAM rating model uses a
scoring system to rank sites for priority attention (Fig. 1).
Figure I
Risk Assessment and Management Rating Methodology Flow Chan
The model uses data readily obtained during the evaluation of
past and current operations and field inspections. Scoring JW
176 RISK ASSESSMENT/DECISION ANALYSIS
-------
ments and computations are easily made. In assessing the hazards
at a given site, the model develops a score based on the physical
characteristics of the system, the most likely routes of contamina-
tion and the worst hazards of the site. Sites are given low scores
only if there are clearly no hazards at the site and the tank system
is in very good condition.
This model considers five aspects of the hazards posed by a
specific site:
• The physical characteristics of the system
• The possible receptors of the contamination
• The product and its characteristics
• Potential pathways for product contamination migration
• Product management practices
Each category contains a number of rating factors used in the
overall Risk Assessment and Management rating.
The physical characteristics and receptors category ratings are
calculated by scoring each factor, multiplying by a factor weight-
ing constant and adding the weighted scores to obtain a total cate-
gory score.
Pathway Category
The pathways category rating is based on evidence of contam-
inant migration or an evaluation of the highest potential (worst
case) for contaminant migration along one of three pathways. If
evidence of contaminant migration exists, the category is given a
subscore of 80 to 100 points. For indirect evidence, 80 points are
assigned and for direct evidence, 100 points are assigned. If no
evidence is found, the highest score among three possible routes
is used. These routes are surface water migration, flooding and
Table 1
Risk Assessment and Management Rating Methodology Form
DATE OF OPERATION OB OCCURRENCE
COKHEeTS/DESCEIPTIOIf
SO* RATIO BY
OWUEE/OPERATOR .
PHYSICAL CHARACTERISTICS OF TANK SYSTEM
FACTOR KAIIKUH
RATIK HULTI- FACTOR POSSIBLE
ME
A ACI
1. SIZE
C TAB1C COHPOSITIOR-
I . CATHODIC PROTKCTIOV
1 . VISIBLE CORROSIOa-
PIPIBC
F ACE OF PlPIire
C PIPXHC COMPOSITIOK
B . CATHODIC PROTECTION
I, VTSIBLR CORROSIOIf
OTHER
* RELEASE DETECTIOH
I. HOBITOR»C WELLS
B. MIITOIA1ICI Aim IIPAIR HISTORY
7
5
10
6
10
7
10
<
10
5
4
5
21
15
JO
IB
30
21
30
IB
30
15
_ 12
»
Phyi. char. Subacore: (100 x factor aeor* eubtotal/aaxli
II. RECEPTORS
I aeore aubtotal).
FACTOR HAXIHUH
RATIHC RULTI- FACTOR POSSIBLE
A. POPULATIOB UTTHTI 1.OOO FRET OF SITI
«. DISTAMCE TO IEAREST WILL
C. LAID USE/Zomc WITHU 1 KILE RADIUS
0. OISTAUCE TO RESKEVATIOE' BOIWDAEY
E. CRITICAL EWIEOnODJTS WTTHIV 1 KILE RADIUS
OF IITE
E, MATER OUALITY or HXAREST SURFACE WATER BODY
5, CEOmDWATEB USE OF UPPERMOST AQUIFER
«• POPULAtlOe- SERVED BY SURFACE WATER SUPPLY
WITHIB 3 HILES DOVMSTREAH OF SITE
I. POPULATIOII SERVED BY CROUHDWATER SUPPLY
WITHM 3 KILES OF SITE
4
10
3
t
10
'
9
t
*
12
30
1
IB
30
IB
2'
11
18
subtotala 1BO
groundwater migration. Evaluation of each route involves factors
associated with the particular migration route. The three path-
ways are evaluated and the highest score among all four of the
potential scores is used.
Product Characteristics Category
The product characteristics category is scored in three steps.
First, a point rating is assigned based on an assessment of the pro-
duct quantity and the hazard (worst case) associated with the site.
The level of confidence in the information is also factored into the
assessment. Next, the score is multiplied by a product persistence
factor, which reduces the score if the product is not very persis-
tent. Finally, the score is further modified by the physical state of
the product. Liquid products receive the maximum score, while
scores for sludges and solids are lower.
Summation
The scores for each of the four categories are then added to-
gether and normalized to a maximum possible score of 100. Then
the product management practice category is scored. The final
site score is calculated by applying the product management prac-
tices category factor to the sum of the scores for the other four
categories. The higher the score, the more risk can be assumed.
XII. PBODUCT CHARACTERISTICS
A, Select the factor ecore baaed on the eatla«ted quantity, the degri
and the confidence level of the information.
L. Product quantity (S - null, H - BedluB, L • large)
z. Confidence Level (C • confined, 6 • euepeeted
J. Heterd ratlin <« * hl«h. • - •edlua, L - low)
Factor Subeeore A (fro* 20 to 100 baaed on factor aeore Batrix)
B. Apply peralatanee factor
Factor Subacora A I Paralatance Factor • Rubacore B
i of hazard.
Apply phyaical atate eultlpller
Subecon I I Phyaical State Multiplier - Product Characterlatlca Subacore
IV. PATHWAYS
RATI1IC FACTOR
FACTOR HAXIHUH
RATIW FACTOR POSSIBLE
(0-3) MULTIPLIER SCORE SCORE
A. If there la evidence of nitration of hezerdoua contavinanta, aeaian •axinm
factor aubecore of 100 pointa for direct evidence or BO pointa for Indirect
evidence. If direct evidence exlata then proceed to C. If no evidence or
Indirect evidence exlata. proceed to B.
Subacore
B. Rate the »Lgretlon potential for 3 potential pathwaye: aurfaee water edgra-
tlon, flooding and groundwatar ailgratlon. Select the hitheat rating and
proceed to C.
1. Surface water Migration
Diitanca to tta..raat Surfae* Uatar
Mat Precipitation
Surfaca aroaion
Surfaea »ar.M..bilitr
Hainfall intanaitv
B
t
a
i
e
24
18
24
IB
24
Subacora (100 X factor aeor* mibtotal/euxiwrn icor* .nibtotal)
*• Flooding l
Subieor* (100 x factor •cor*/3)
3. GrounoVator migration
Deotb to iroundwater
let preclBltatlon
Soil peneebllltv
Subeurfaca flowa
Direct aeceaa to iroundwater
B
*
B
•
«
24
18
24
54.
24
Subtotal*
••capton tubfcor* (10O Z factor acora nibtotal/•etxinua acor* tubtotal)..,,,
Subacora (100 x factor acora nbtotal/maxiiKim aeora aubtotal)
Hi(hait pathway nibieora.
Bntar tha hifthast cubacora valua fro* A. 8-1. V-2, or 1-3 abova.
Pathwaya Subieor*
RISK ASSESSMENT/DECISION ANALYSIS 177
-------
rttjrilc*. Ch*ro.etorlotLe«
•ocoptoro
Uooto ChorcctorLotlc*
PothmfOfi
Totol eUvUod »r « •
Oroot
• . PIODUCT KAtUCDOVT PUCTICtS FACTO!
rt* oultipllor OrLvod bolow to thon •pfUoe] t* tho t*lav
polnto (Croio Total tcoro) fro» Port A ok«voi
I . U«4iMt« •Mltorln* mil* O.OJ
4. ••tt*f*ct*T7 tjBMVMUf f ••>>••• pr*c«dur*i o.u
1. rutiOul •• f*r fillip tinU •»*! h«v« •4*vu*t«
pncMitL4M cvcovOLAf •jill* €•• •"•rflflao O.OS
t. lff*etlr« 4«ll7 laoMilarr r«c«r4 o.u
1. Mf*cuar4« «4«UMt ^r*4uct UM/t 0.09
0. F«rU4U »«* tMtUt fir Udu O.U
T«U1 0««« •• *tllr ewtk »f l-n*« l*r ~l«r M-l««t 0.05
10. TnUU* fntrm ~* «rUr» urtUtutU* f«r
l*«k«4« t««tlag. •ylll e««tr»l M4 ^i«r(anc7 pr«««4ur«« O.U
11. Tvik* ftM La ••rvlc* H'«y« iy tit^fttrimt *t «^tl*4 Q.M
1 «v*ru« rlik Ou^*Cat« Total* aH>
•urm«t« T»t«l) . riitiil luoamnl mctttu f«Ur
For »«ch of tho olovon factor* Ilito4 holow. ctomilotlvolr »*M rotUki
valttoo to fot ta ouc«t*t* totoli
1. PHYSICAL CHARACTERISTICS CATEGORY
Rating Factors 0
A. Age of Tank 0-2 years
B. Size less than 500 gal
C. Tank Composition 0
0. Cathodic Protection High Amount
E. Visible Corrosion None
F. Age of Piping 0-2
G. Piping Composition 0
H. Cathodic Protection High Amount
1. Visible Corrosion None
J. Loose Fittings/Breakage None
K. Release Detection High Amount
L. Monitoring Metis High Amount
H. Maintenance and Excellent
Repair History
1 1 . RECEPTORS CATEGORY
c. Cr**« l«t«l Cc*r« l Product ••>nj»^it Pr«ctu«« r«cl«r • rUil lc*n
I . _
Tible 2
RJtk Aneumenl «nd Miugcment
Rating Methodology Guidelines
Rating Scale levels
1 2 3 Multiplier
2-5 5 10 greater than 10 7
500-2,000 1.000 - 5,000 greater than 5,000 5
Fiberglass Protected Steel Unprotected Steel 10
(Non-N»tallic)
Medium Low None 6
Low Medium High 10
2-5 5-10 greater man 10 7
Flberglass-PVC Protected Steel Unprotected Steel 10
(Non-Metallic)
Medium low None 6
Low Medium High 10
low Medium High 7
Medium low None 5
Medium IOM None 4
Good Fair Poor 5
Rating Scale Levels
Rating Factors 0
A. Population within 1,000 0
feet (includes on-base
facilities)
8. Distance to nearest Greater than 3 miles
water wel 1
C. Land Use/Zoning Completely remote
(within 1 mile radius) (zoning not applicable)
1 2 J Multiplier —
1 25 26 100 Greater than 100 '
1 to 3 miles 3,001 feet to 1 0 to 3,000 feet «>
mile
Agricultural Ccnmercial or Residential 5
Industrial
178 RISK ASSESSMENT/DECISION ANALYSIS
-------
D. Distance to Installa-
tion boundary
E. Critical environments
(within I mile radius)
Greater than 2 miles I to 2 miles
Not a critical
environment
F. Ground Hater use of
designation of nearest
surface water body
G.
Groundnater use of
uppermost aquifer
Agricultural or
industrial use.
Not used, other
sources readily
available
H. Population served by 0
Surface water supplies
within 5 miles down-
stream of site
I. Population served by 0
aquifer supplies within
3 miles of site
Natural areas
Recreation, propa-
gation and manage-
ment of fish and
wildlife.
1,001 feet to I
mile
Pristine natural
areas, minor wetlands;
preserved areas; pre-
sence of economically
important natural
resources susceptible
to contamination
Shellfish propaga-
tion and harvesting
Conrnercial, Indus- Drinking water
trial, or irriga- municipal water
tion, very limited available.
other water sources.
I 50
I 50
51 1,000
51 - 1,000
0 to 1,000 feet
Major habitat of an
dangered or threatened
species; presence of
recharge area; major
wetlands.
Potable water supplies
Drinking water, no muni-
cipal water available;
commercial, industrial,
or irrigation, no other
water source available.
Greater than 1,000
Greater than 1,000
6
10
III. PRODUCT CHARACTERISTICS
A-1 Product Quantity
S - Small quantity (500 - 1,000 gals)
H - Moderate quantity (1,000 - 10,000 gals)
L - Large quantity (greater than 10,000 gals)
A-2 Confidence Level of Information
C - Confirmed confidence level (minimum criteria below)
0 Verbal reports from Interviewer (at least 2) or written
information from the records.
0 Knowledge of types and quantities of products used
by shops and other areas on base.
0 Based on the above, a determination of the types and
quantities of product at the site.
A-J Risk Rating
S - Suspected confidence level
0 No verbal reports or conflicting verbal reports and no
written information from the records.
0 Logic based on a knowledge of the types and quantities of
products generated at the base, and a history of past
product management practices indicate that these products
used at a site.
Rating Scale Levels
Risk Category
Toxic ity
Ignitability
Use the highest individual
0
Sax's Level 0
Flash point greater than
200° F
rating based on toxicity or
Hazard Rating
High (H)
Hedium (H)
Low (L)
1
Sax's Level 1
Flash point at 140° F
to 200°
ignitability and determine
Points
J
2
1
2 }
Sax's Level 2 Sax's Level 3
Flash point less than Flash point less than
80°F to I40°F 80°F
the risk rating.
RISK ASSESSMENT/DECISION ANALYSIS 179
-------
III. PRODUCT CHARACTERISTICS (Continued)
Product Characteristic Matrix
Point
Rating
100
80
70
60
50
40
50
Product
Quantity
I
I
n
i
s
H
I
I
M
S
S
M
N
L
S
M
S
Confidence level
of Information
C
C
C
S
C
C
S
C
s
C
s
s
C
s
C
s
s
Risk
Rating
H
H
H
H
H
H
H
L
H
M
H
H
I
L
I
I
M
20
B. Persistence Multiplier for Point Rating
Persistence Criteria
Metals, polycyclic compounds and halogenated hydrocarbons
Substituted and other ring compounds
Straight chain hyrdrocarbons
Easily biodegradable compounds
C. Physical State Multiplier
Physical State
liquid
Sludge
Solid
Motes:
For a site Mitti more than one hazardous product, the product
quantities may be added using the following rules:
0 Confirmed confidence levels (C) can be added
° Suspected confidence levels (S) can be added
0 Confirmed confidence levels cannot be added with
suspected confidence levels
Product Risk Rating
0 Hastes witti the vane hazard rating can be added
0 Hastes with different hazard ratings cm only be added
in a downgrade mode, e.g., MCH « SCH - ICK if the total
quantity is greater than 20 tons.
Example: Several products m»y be present at a site, each
having an NCM designation (60 points). By adding th>
quantities of each product, the designation may change to
ICM (80 paints). In this case, the correct point rating for
the product is 80.
Multiply Point Rating from Part A by the following
1.0
0.9
O.B
0.4
Multiply Point Total Fro» Parts A and B by the Following
1.0
0.75
0.50
IV PATHWAYS CATEGORY
A. Evidence of Contamination
Direct evidence is obtained fro* laboratory analyses of hazardous contaminants present above natural background levels in svfact
water, groundwater, or air. Evidence should confirm that the source of contamination is the site being evaluated.
Indirect evidence might be from visual observation (i.e., leachate), vegetation stress, sludge deposits, presence of taste and odors in
drinking water, or reported discharges that cannot be directly confirmed as resulting from the site, but the site is greatly sospecM
of being a source of contamination.
B-l POTENTIAL FOR SURFACE MATER CONTAMINATION
Rating Factors
Rating Scale levels
water (includes drainage
ditches and storm sewers)
Net precipation
Surface erosion
Surface permeability
Rainfall intensity based
on I year 24-hr rainfall
0
Greater than 1 mi le
1
2,001 feet to 1
mile
2
501 feet to 2,000
feet
5
0 to 500 feet
Multiplier,
less than -10 in.
None
01 to I5t clay
-2
•10 to 4 in.
Slight
151 to Wlclay
-2 -4
»5 to 20 in.
Moderate
JOt to 501 clay
-4 -6
Greater than -20 in.
Severe
Greater than 501 clay
-6
(greater than 10 cm/sec) (10 to 10 cm/sec) (10 to 10 cm/sec) (less than 10 cm/sec)
less than 1.0 inch
1.0-2.0 I runes
2.1-5.0 Inches
greater than 5.0 inches
180 RISK ASSESSMENT/DECISION ANALYSIS
-------
IV PATHWAYS CATEGORY (Continued)
B-2 POTENTIAL FOR FLOODING
Floodplain
Rating Factors
Beyond 100-year
f loodplain
0
In 25-year flood- In 10-year flood- Floods annually
plain plain
Rating Scale Levels
1
2 5
B-5 POTENTIAL FOR GROUNOUATER CONTAMINATION
Depth to groundwater
Net precipiation
Soil permeability
Subsurface flous
Greater than 500 feet
Less than -10 in.
Greater than 50% clay
-6
(greater than 10 cm/sec)
Bottom of site greater
than 5 feet above
high grounduater level
50 to 500 feet
-10 to +5 in.
Kit to 501 clay
-4 -6
Bottom of site
occasionally
submerged
II to 50 feet 0 to 10 feet
+5 to +20 in. Greater than +20 in.
151 to JOT clay 01 to 151 clay
-2 -4 -2
(10 to 10 cm/sec) 10 to 10 cm/sec)
Bottom of site Bottom of site locate
frequently sub- below mean groundwate
merged
Multiplier
8
6
8
less than 10 cm/sec)
Direct Access to ground-
water (through faults,
fractures, faulty uelI casings,
subsidence fissures, etc.)
No evidence of risk
Lou risk
Moderate risk
High risk
V PRODUCT MANAGEMENT PRACTICES CATEGORY
A. This category adjusts the total risk as determined from the physical characteristics, receptors, pathways and product
characteristics categories for product management practices and engineering controls designed to reduce this risk. The total risk
is determined by first averaging the receptors, pathways and product characteristics subscores. Then from Part B below, a
management factor is computed and subtracted from the number I to get a decimal multiplier.
B. PRODUCT MANAGEMENT PRACTICES FACTOR
The multiplier derived below is then applied to the total average risk points from Part A above:
For each of the eleven factors listed below, cumulatively add rating values to get an aggregate total:
PRODUCT MANAGEMENT PRACTICES
I. Liners in good condition
2. Sound dikes and adequate freeboard
5. Adequate monitoring wells
4. Satisfactory emergency response procedures
5. Procedures for filling tanks must have adequate precautions regarding spills and overflows
6. Effective daily inventory record
7. Safeguards against product theft
B. Periodic tank testing for leaks
9. Daily check of tanks for water content
10. Training program and employee certification for leakage testing, spill control and emergency procedures
II. Tanks not in service properly safeguarded or emptied
Aggregate Totals
RATING VALUE
0.10
0.10
0.05
0.10
0.05
0.10
0.05
0.10
0.05
0.10
0.05
(I - Aggregate Total) - Product Management Practices Factor
RISK ASSESSMENT/DECISION ANALYSIS 181
-------
The U.S. EPA's Methodology for Adjusting
The Reportable Quantities of Potential Carcinogens
Vincent James Cogliano, Ph.D.
U.S. Environmental Protection Agency
Office of Health and Environmental Assessment
Washington, D.C.
ABSTRACT
CERCLA Section 102 designates a list of hazardous substances
and establishes statutory reportable quantities (RQs) for them.
The federal government must be notified whenever one of these
substances is released in a quantity greater than or equal to its
RQ. CERCLA gives the U.S. EPA the authority to adjust RQs as
appropriate. The U.S. EPA is now about to adjust the statutory
RQs of most potential carcinogens. To support this effort, the
U.S. EPA's Carcinogen Assessment Group has developed a meth-
odology for ranking potential carcinogens. This methodology is
based on two factors—weight of evidence and potency—that the
Carcinogen Assessment Group considers essential to describing a
carcinogenic hazard. This paper describes the methodology and
the supporting rationale.
INTRODUCTION
CERCLA Section 102 designates a list of hazardous substances
and establishes statutory reportable quantities (RQs) for them.
The federal government must be notified whenever one of these
substances is released in a quantity greater than or equal to its
RQ. CERCLA gives the U.S. EPA the authority to adjust RQs as
appropriate.
No determination has been made that the release of a substance
at or above its RQ will be hazardous. The RQ is merely a trigger
for notification. Many considerations will affect the
government's decision about whether and how it should respond
to a particular release. The location of the release, its proximity to
drinking water supplies or other valuable resources, the likelihood
of exposure or injury to nearby populations, remedial actions
taken by responsible parties and other factors must be assessed by
the federal on-scene coordinator on a case-by-case basis.
By the end of 1986, the U.S. EPA will have promulgated or
proposed three rules to adjust the statutory RQs of most of the
717 CERCLA hazardous substances. The first two rules deal with
hazardous substances that are not potential carcinogens, and the
third rule deals with the potential carcinogens. The first rule,1
published on April 4, 1985, adjusted the statutory RQs of 340
hazardous substances that are not potential carcinogens. On the
same date, the U.S. EPA also published a Notice of Proposed
Rulemaking for the second rule.2 The final second rule, which will
adjust the statutory RQs of another 102 hazardous substances,
should be promulgated before this paper appears in print. Also
anticipated is the Notice of Proposed Rulemaking for the third
rule, which will adjust the statutory RQs of most potential carcin-
ogens. The final third rule should be promulgated in 1988 after a
review of public comment. The U.S. EPA's Office of Solid Waste
and Emergency Response (OSWER) decided to separate the po-
tential carcinogens in this manner so that the other statutory RQs
could be adjusted while a methodology for ranking potential car-
cinogens is developed, the potential carcinogens are ranked and
there is public comment on the methodology and rankings.
CERCLA gives the U.S. EPA wide discretion in adjusting RQs.
The U.S. EPA has chosen to use the five RQ levels—1, 10,100,
1,000 and 5,000 Ibs—originally established pursuant to Section
311 of the Clean Water Act. RQs are adjusted after evaluating
each hazardous substance for its intrinsic physical, chemical and
lexicological properties. Six properties, called primary criteria,
are considered: aquatic toxicity, mammalian toxicity, ignitability,
reactivity, chronic toxicity and potential carcinogenicity. Each of
the six primary criteria is ranked on a five-tier scale that cor-
responds to the five RQ levels. The lowest of these six tentative
RQs becomes the hazardous substance's primary criteria RQ.
After the primary criteria RQ is assigned, the hazardous
substance is evaluated further for susceptibility to certain degra-
dative processes. Three processes are considered: biodegradation,
hydrolysis and photolysis. If a hazardous substance degrades
relatively rapidly to form a less harmless substance, then its
primary criteria RQ is raised one level unless the substance is also
bioaccumulative, environmentally persistent, highly reactive or
otherwise unusually hazardous. If a hazardous substance
degrades to form a more harmful substance, then its primary
criteria RQ is replaced by the RQ for the more harmful substance.
This RQ, determined after considering the six primary criteria and
three degradative processes, becomes the hazardous substance's
adjusted RQ for the purpose of rulemaking.
OVERVIEW OF THE METHODOLOGY
To identify which CERCLA hazardous substances should be
ranked on potential carcinogenicity, OSWER relies on four
sources: annual reports on carcinogens from the National Toxi-
cology Program, monographs of the International Agency for
Research on Cancer, final determinations published by the U.S.
EPA in the Federal Register that identify a substance as a poten-
tial carcinogen and determinations by the U.S. EPA's Office of
Health and Environmental Assessment that a substance may be a
potential carcinogen. If a substance is identified as a potential car-
cinogen, then its adjusted RQ is based on all six primary criteria.
If a substance is not identified as a potential carcinogen, then its
adjusted RQ is based on the other five primary criteria.
The U.S. EPA has decided to treat potential carcinogenicity
with more caution than the other primary criteria. This decision
recognizes a number of positions that the U.S. EPA has taken re-
peatedly with respect to cancer and is thought to be in concert
with prudent public health concerns:
• Threshold levels of exposure, below which there is no risk of
cancer, have not been demonstrated.3'4'5 Thus the release of
182 RISK ASSESSMENT/DECISION ANALYSIS
-------
any quantity of a potential carcinogen may increase the risk of
cancer in the exposed population. This is in contrast to most
other toxic effects for which thresholds can be demonstrated.
• Cancer risks are considered to be cumulative.3 A number of
small releases can be as serious as a single large release.
• Cancer is not immediately manifested.4'5 There is a latent period
between exposure to a carcinogen and the manifestation of
cancer that makes it impossible to directly observe carcinogenic
risks from substances newly released into the environment.
This period of delay is in contrast to acute toxic effects which
are more immediately manifested.
Partly for these reasons, OWSER has decided to adopt a 100-lb
maximum RQ for potential carcinogens, so the 1,000-lb and
5,000-lb RQ levels are not used for potential carcinogens. Because
three RQ levels are left to be used, potential carcinogens are ranked
on a three-tier scale (High, Medium and Low) that corresponds to
RQ levels of 1, 10 and 100 Ibs.
The U.S. EPA's Carcinogen Assessment Group (CAG), part of
the Office of Health and Environmental Assessment, has devel-
oped the methodology for ranking the potential carcinogens
High, Medium or Low. This methodology is based on two factors
—weight of evidence and potency—that CAG believes are essen-
tial to describing a carcinogenic hazard. Weight of evidence is a
qualitative evaluation of the strength of the case that a substance
causes cancer in humans. Potency is a quantitative estimate of the
strength of a substance to cause cancer. These two factors are
evaluated separately and then are combined to arrive at the three-
tier hazard ranking. The rest of this paper describes these two fac-
tors and how they are combined.
WEIGHT OF EVIDENCE—
THE QUALITATIVE PHASE
Weight of evidence is a qualitative evaluation of the strength of
the case that a substance causes cancer in humans. Partly to en-
courage consistent evaluations, the U.S. EPA published its pro-
posed guidelines for carcinogen risk assessment.3 These guidelines
call for the evaluation of all pertinent human, animal and in vitro
studies. The rest of this section is a paraphrase of the system for
classifying the weight of evidence.
Evidence of carcinogenicity from human studies comes from
case reports of individual cancer patients, descriptive epidemi-
ologic studies and analytical epidemiologic (case-control and co-
hort) studies. Three criteria must be met before a causal associa-
tion can be inferred between exposure and cancer in humans:
there is no identified bias that could explain the association, the
possibility of confounding has been considered and ruled out as
explaining the association and the association is unlikely to be due
to chance. The degree of evidence for carcinogenicity is then sum-
marized as:
• Sufficient (there is a causal relationship)
• Limited (a causal interpretation is credible)
• Inadequate (chance, bias or confounding could not adequately
be excluded, or there were few pertinent data)
• No data
• No evidence (no association was found in well-designed and
well-conducted independent analytical epidemiologic studies)
Evidence of carcinogenicity from animal studies is summarized
as:
• Sufficient—there is an increased incidence of malignant tu-
mors in multiple species or strains, in multiple experiments or
to an unusual degree with regard to high incidence, unusual
site or type of tumor or early age at onset.
• Limited—the data suggest a carcinogenic effect but are limited
because the studies involve a single species, strain, or experi-
ment and do not meet the criteria for sufficient proof; the ex-
periments are restricted by inadequate dosage levels, inade-
quate duration of exposure, inadequate period of follow-up,
poor survival, too few animals or inadequate reporting; or
the studies show an increase in the incidence of benign tumors
only.
• Inadequate — the studies cannot be interpreted as showing
either the presence or absence of a carcinogenic effect.
• No data
• No evidence — there is no increased incidence of neoplasms in
at least two well-designed and well-conducted animal studies in
different species.
Based on the combined evidence for carcinogenicity for human
and animal studies, a substance is classified into one of five
weight-of-evidence groups:
• Group A — Human Carcinogen — sufficient human evidence
• Group B — Probable Human Carcinogen — limited human evi-
dence, or sufficient animal evidence in the absence of suffici-
ent or limited human evidence; this group is divided into two
subgroups: usually Group Bl is reserved for substances with
limited human evidence, and Group B2 for substances with
sufficient animal evidence in the absence of sufficient or lim-
ited human evidence
• Group C— Possible Human Carcinogen— limited animal evi-
dence in the absence of sufficient or limited human evidence
• Group D — Not Classifiable — inadequate human and animal
evidence or no data
• Group E — Evidence of Non-Carcinogenicity for Humans — no
evidence for carcinogenicity in at least two adequate animal
tests in different species or in both adequate epidemiologic
and animal studies
All relevant supporting information then is evaluated to see if
the overall weight of evidence should be modified. Relevant fac-
tors to be included along with the tumor information from human
and animal studies are: structure-activity relationships; short-
term test findings; results of appropriate physiological, biochem-
ical and lexicological observations; and comparative metabolism
and kinetic studies. The nature of these findings may cause one to
adjust the overall weight of evidence.
POTENCY— THE QUANTITATIVE PHASE
Potency is a quantitative estimate of the strength of a substance
to cause cancer in humans. Potencies are calculated for sub-
stances in Groups A, B and C that have suitable dose-response
data. Potencies are not calculated for substances in Groups D and
E, since they are not properly called potential carcinogens.
A prime concern in ranking hazardous substances is the need
for consistency and comparability across substances. In accor-
dance with the U.S. EPA's proposed guidelines for carcinogen
risk assessment3 and with the U.S. EPA's practice in numerous
risk assessments, the multistage model has been chosen for
estimating potency. According to the multistage model with k
stages, the lifetime increased cancer risk from a lifetime dose of D
milligrams of carcinogen per kilogram of body weight per day is:
P(D) = 1 - exp - (q]D + q2D2 + . . . + qkDk) (1)
For adjusting statutory RQs, the potency is defined as the
reciprocal of the estimated dose associated with a lifetime increased
cancer risk of 10% (ED10). That is, the potency is 1/ED10 where
P(ED10) = 0.10. This measure of potency has been chosen in-
stead of the upper bound on the linear coefficient (q{*) that CAG
regularly uses to estimate potency because:
RISK ASSESSMENT/DECISION ANALYSIS 183
-------
• It is relatively insensitive to the choice of the dose-response
model, so the potency rankings are not distorted by the choice
of any particular dose-response model.
• It does not require extrapolation beyond the observed data, be-
cause a 10% response is usually within the observed range.
• It is a statistically stable estimate, in contrast to the measure
QJ*, which requires the use of upper bounds to ensure stabil-
ity. (It should be noted that other elements of the methodol-
ogy, such as the use of the most sensitive animal species, intro-
duce non-statistical upper bounds into the potency estimate.)
The selection of dose-response data for fitting the multistage
model follows the U.S. EPA's proposed guidelines. Human
studies are preferred to animal studies, although they need to be
considered case by case. Otherwise the data set from the long-
term animal studies showing the greatest sensitivity is used, with
due regard to biological and statistical considerations. Animals
with one or more tumor sites or types showing significantly
elevated tumor incidence are pooled, and benign tumors generally
are combined with malignant tumors unless the benign tumors are
considered to have the potential to progress to the associated
malignancies. In the absence of comparative lexicological,
physiological, metabolic and kinetic information, extrapolation
to humans is made on the basis of body surface area. Finally, to
adjust for the smaller number of tumors expected in a less-than-
lifetime study, the potency is increased by the third power of the
ratio of the animal's lifespan to the study's duration.
The potential carcinogens are classified into potency groups as
follows:
• Group 1— 1/ED10 above 100 (highest potency)
• Group 2—1/ED 10 between 1 and 100
• Group 3— 1/ED10 below 1 (lowest potency)
For some potential carcinogens, the dose-response data are not
suitable for estimating potency. In most of these cases, the
substance is assigned to Group 2 as if it had a mid-range potency.
In a few of these cases, however, the data indicate a possibly high
potency because every dosed animal developed cancer, so the sub-
stance is assigned to Group 1.
Because 1/ED10 is not the usual measure of potency, CAG has
investigated how it is related to q, *, its usual measure of potency.
If a straight line were drawn between the 10% response point and
the origin, the slope of that line would be one-tenth of the value
1/ED10. Thus 1/ED10 should be approximately 10 times q,*, an
upper bound on the slope. There are three reasons why this factor
of 10 may not hold in general. Because the dose-response curve
usually lies below this straight line at very small doses, the factor
should be increased. Because q, * is an upper bound, the factor
should be decreased. And because upper bounds to not always
overestimate by the same amount, there should be some spread
around the factor.
Empirical analysis of the CERCLA potential carcinogens
shows that 1/ED10 is closely related to q,*. In Fig. 1, the loga-
rithm of 1/ED10 is plotted against the logarithm of q,* for 86
substances where both could be computed independently from
the same data set. (This excludes substances where the dose-re-
sponse data are not suitable for estimating potency, where the po-
tency is based on a related substance or where 1/ED10 is com-
puted directly from 11 * as estimated from a human study.) The
logarithmic transformation is used to equalize the variances of
estimates that range over several orders of magnitude. There is
very little deviation from a straight-line fit; the correlation is 0.99.
Linear regression yields:
The result is equivalent to saying that 1/ED10 averages about 6
times qj*.
This close relationship between 1/ED10 and q(* demonstrates
that a ranking of potential carcinogens based on 1/ED10 should
agree with a ranking based on q, *. This agreement, together with
the other advantages of 1/ED10 cited earlier, has led CAG to
choose 1/ED10 as the measure of potency to be used in adjusting
statutory RQs.
Figure 1.
Correlation of I/ED 10 and QI -
COMBINATION OF WEIGHT
OF EVIDENCE AND POTENCY
Hazard rankings are based jointly on two factors—weight of
evidence and potency—that CAG believes are essential to describ-
ing a carcinogenic hazard. Hazard rankings of High, Medium and
Low are assigned so that the hazard ranking increases as either the
weight of evidence or the potency increases. Table 1 shows how
hazard rankings are assigned.
Table 1
Hazard Ranking Assignments
1
Potency group
2
Welght-of-
evldence
group
A
B
C
D
E
High High Medium
High tedium Low
tedium Low Low
No hazard ranking
No hazard ranking
log 1/ED10 = 0.8 -I- 1.0 x logq,* (R2 = 0.99)
(2)
Depending on whether a substance falls into potency groups 1.
2 or 3, a hazard ranking of High, Medium or Low is assigned to
Group B carcinogens. Hazard rankings are one level higher
(High, High or Medium) for Group A carcinogens. This increased
concern is justified because there is direct human evidence
establishing that Group A substances cause cancer. Hazard rank-
ings are one level lower (Medium, Low or Low) for Group C car-
cinogens. This reduced concern is justified because the evidence
implicating Group C substances is less certain, as it may be either
unreplicated or of marginal biological or statistical significance.
Before settling on these hazard ranking assignments, alternative
ranking schemes were considered. Proposals that all Group A
substances be ranked High or that all Group C substances be
ranked Low were rejected because CAG believes strongly that
184 RISK ASSESSMENT/DECISION ANALYSIS
-------
potency is essential to describing a carcinogenic hazard. Similarly, a
proposal to base hazard rankings on potency alone was rejected
because CAG believes that weight of evidence must be considered
as well. It is CAG's judgment that the chosen ranking scheme gives
proper consideration to both weight of evidence and potency.
Because CAG believes that both weight of evidence and poten-
cy are essential to describing a carcinogenic hazard, it is in-
teresting to see whether the two concepts are related. An empirical
analysis of the CERCLA potential carcinogens shows that there is
no striking relationship between weight of evidence and potency.
Table 2 is a cross-tabulation of substances by weight of evidence
and potency. It excludes substances where the dose-response data
are not suitable for assigning a potency group and a mid-range
potency is assigned, or where the potency group is based on a
related compound.
Table 2
Count of Substances by Weight of Evidence and Potency
Potency group
1 2 3
Total
Weight-of-
evidence
group
A
Bl
B2
C
Total
5
2
23
1
31
3
4
50
5
62
2
0
16
5
23
10
6
89
11
116
There are good reasons not to expect a correlation. A high
potency means that relatively small doses of a substance cause
cancer. A high weight of evidence means that there is a good epi-
demiologic study making a credible case that a substance causes
cancer. These are not the same. The existence of good epidemio-
logic studies depends on many factors, among them the availabili-
ty of a study population that can be followed over a sufficiently
long time, the absence of confounding factors that prevent a
substance from being isolated as a cause of cancer and the interest
and funding of investigators. This lack of correlation reinforces
CAG's position that weight of evidence and potency are two in-
dependent pieces of information that describe a carcinogenic
hazard.
After CAG has completed the hazard rankings, OSWER
translates the hazard rankings of High, Medium and Low into
RQs of 1, 10 and 100 Ibs. OSWER then compares these RQs with
the RQs for the other primary criteria and evaluates the degrada-
tive processes before adjusting the statutory RQs in a rulemaking.
CONCLUSIONS
The U.S. EPA is now about to adjust the statutory reportable
quantities of most potential carcinogens. To support this effort,
the U.S. EPA's Carcinogen Assessment Group has developed a
methodology for ranking potential carcinogens. This methodol-
ogy is based on two factors—weight of evidence and potency—
that the Carcinogen Assessment Group considers essential to de-
scribing a carcinogenic hazard.
ACKNOWLEDGMENT
The author wishes to thank the members of the U.S. EPA's
Carcinogen Assessment Group; John E. Riley, K. Jack Koo-
yoomjian and Ivette Ortiz of U.S. EPA's Office of Solid Waste
and Emergency Response; and Gregory R. Ricci and Jeffrey S.
Gift of Environmental Monitoring and Services, Inc. (a wholly
owned subsidiary of Combustion Engineering, Inc.), for their in-
valuable support and assistance in preparing this manuscript.
REFERENCES
1. U.S. EPA, "Notification Requirements; Reportable Quantity Ad-
justments." Federal Register, Apr. 4, 1985, 50, 13456-13513.
2. U.S. EPA, "Reportable Quantity Adjustments." Federal Register,
Apr. 4, 1985, 50, 13514-13522.
3. U.S. EPA, "Proposed Guidelines for Carcinogen Risk Assessment."
Federal Register, Nov. 23, 1984, 49, 46294-46301.
4. Office of Science and Technology Policy, "Chemical Carcinogens; A
Review of the Science and Its Associated Principles," Federal Regis-
ter, Mar. 14, 1985, 50, 10372-10442.
5. National Research Council, Risk Assessment in the Federal Govern-
ment: Managing the Process. National Academy Press, Washington,
DC, 1983.
RISK ASSESSMENT/DECISION ANALYSIS 185
-------
Quantitative Risk Assessment as the Basis
For Definition of Extent of Remedial Action
At the Leetown Pesticide Superfund Site
u.s
Amy E. Hubbard
Robert J. Hubbard
John A. George
NUS Corporation
Pittsburgh, Pennsylvania
William A. Hagel
Environmental Protection Agency
Philadelphia, Pennsylvania
ABSTRACT
A study of comparative public health risk was undertaken by
the U.S. EPA in conjunction with a Remedial Investigation of the
Leetown Pesticide Superfund Site. The 2'/z mile^ area encompass-
ing the site includes a watershed tributary to the Potomac River
and is approximately 5 miles west of Harper's Ferry, West Vir-
ginia.
Hazardous waste activity at the Leetown site included both
land disposal of pesticides and accumulation of pesticide residues
in soils of former orchards within the study area. In defining
source areas within the watershed to be considered candidates for
remedial action, the U.S. EPA used quantitative risk evaluation,
comparative levels of residual contamination and the character of
the hazardous waste activity (i.e., disposal versus agricultural
application).
By thoroughly characterizing a total of six suspected pesticide
source areas, the U.S. EPA was able to focus remedial action on
an area of land disposal and two areas where concentrated
residual pesticide levels had occurred as a result of improper
storage and careless handling of pesticides during mixing opera-
tions. In so doing, the U.S. EPA avoided establishing the prece-
dent at this site of using Superfund monies to remediate residual
contamination resulting solely from agrichemical application.
This paper presents the basis for characterization of the source
areas and the rationale employed by the U.S. EPA in establishing
the scope and extent of remedial actions required at the Leetown
Pesticide Site.
INTRODUCTION
An evaluation of comparative public health risk posed primar-
ily by the presence of residual pesticide levels in soils at the
Leetown Pesticide Superfund Site was performed in conjunction
with a Remedial Investigation (RI) of the site. In addition to
quantifying risk, the evaluation played an important role in the
definition of candidate source areas to be remediated and in the
establishment of target levels for remedial action. Reliance upon
the risk evaluation, at least in part, was especially useful at the
Leetown Pesticide Site since the pesticide residual in soil resulted
not only from unauthorized land disposal, but also from typical
use of pesticides in insect control on orchards within the study
area in the 1940s and 1950s.
Risk assessments estimate the magnitude and probability of
harm to public health or the environment as a result of the release
of a hazardous substance. In the present case, probable con-
tamination migration pathways were first characterized to serve
as a basis for definition of a comprehensive, basin-wide environ-
mental sampling program. The chemical analytical results ob-
tained served as input to accepted models of environmental fate
and transport phenomena, resulting in calculation of anticipated
doses at receptors. The anticipated health risk was then calculated
based on assumptions regarding the probability of exposure via
various routes (e.g., dermal contact, inhalation of particulates).
By basing the risk assessment on actual empirical data and ex-
trapolating from the data base where necessary to approximate
future contaminant distribution, it was possible to define baseline
risks which will remain operable unless mitigated by remedial
action.
After evaluating environmental and public health risks, risk-
based goals for cleanup technologies were proposed. The residual
risks associated with each remedial alternative were then con-
trasted to those presented under the baseline or "no action" alter-
native.
LEETOWN
PESTICIDE
SITE
Figure 1
General Site Location
186 RISK ASSESSMENT/DECISION ANALYSIS
-------
DESCRIPTION OF THE LEETOWN
PESTICIDE SITE
The Leetown Pesticide Site is located in northeastern West
Virginia, about 5 miles west of Harper's Ferry in Jefferson Coun-
ty.' Fig. 1 is a general site location map while Fig. 2 provides a
plan of the study area, showing the six areas of suspected
pesticide disposal identified during the RI (see below).
Former Pesticide Pile Area
Former Jefferson Orchard
Former Jefferson Orchard Pesticide Mixing Area
Former Crimm Orchard
Former Crimm Orchard Packing Shed
Suspected Pesticide Landfarm
X
(I) FORMER PESTICIDE PILE AREA
© FORMER JEFFERSON ORCHARD
0 FORMER JEFFERSON ORCHARD PESTICIDE MIXING AREA
@ FORMER CRIMM ORCHARD
(f) FORMER CRIMM ORCHARD PACKING SHED
© SUSPECTED PESTICIDE LANDFARM
Figure 2
Plan of the Study Area
The areas of suspected pesticide contamination lie predomin-
antly within the Bell Spring Run watershed. This watershed drains
to Hopewell Run and, ultimately, to the Potomac River.
The site was first brought to the attention of the West Virginia
Department of Environmental Resources (WVDNR) in 1981. In-
itial concern was raised by personnel from the Leetown National
Fisheries Center (NFC) over the apparent dumping of pesticide-
contamianted debris in the upper reaches of the watershed. The
NFC is a prominent U.S. Fish & Wildlife Service (USF&WS)
research facility located at the base of the Bell Spring Run water-
shed; it specializes in research on infectious fish diseases. In addi-
tion to the NFC, the surrounding agricultural community of Lee-
town utlilizes groundwater from the watershed as its sole source
of potable water.
The area of initial concern relative to pesticide dumping has
been noted in Fig. 2 as the Pesticide Pile Area. At the time of
discovery, it was alleged that this area and a nearby tract of about
50 acres (Suspected Pesticide Landfarm) were repositories for
pesticide-contaminated debris from a fire at a local agrichemical
warehouse. The "pile" was physically removed in 1983 under
direction of the U.S. EPA and the WVDNR; however, sampling
performed during the RI indicated that substantial pesticide con-
tamination still remains at this site. Sampling during the RI did
not provide evidence of similar pesticide disposal at the Suspected
Pesticide Landfarm. Rather, pesticide residuals in the soils of the
landfarm area were consistent with its use for corn production.
The remaining areas of pesticide contamination were associated
with past use of much of the watershed as an orchard. The Jeffer-
son Orchard formerly occupied approximately 170 acres and was
an active orchard during the 1940s and 1950s. A 25-acre tract east
of Route 15/1 subsequently was sold to the Robinson family. The
remainder ultimately was purchased by the USF&WS. The "Rob-
inson Property" apparently was the focus of the orchard opera-
tions and was the most intensively-used portion of the Jefferson
Orchard. A fourth area of pesticide contamination is located at
the southwestern periphery of the Robinson Property. This loca-
tion has been shown on Fig. 2 as the Jefferson Orchard Pesticide
Mixing Area. It was apparently a customary practice in the local
area for orchard pesticides to be mixed at points where roads
crossed streams, primarily due to the easy access to water both to
formulate the sprays and to rinse out the spray equipment.
A second abandoned orchard, the Crimm Orchard, was located
across Bell Spring Run southwest of the Jefferson Orchard. A
former orchard packing shed presently stands in the approximate
middle of the former Crimm Orchard. In addition to serving as a
packing shed, the eastern portion of this land was used for
pesticide formulation and storage.
Presently, there is little evidence of the existence of the or-
chards other than the pesticide mixing areas and the elevated
residual pesticide levels in the soils. These areas now are being
used for production of silage or corn grain as cattle feed and/or
for pasturing dairy cattle.
RISK ASSESSMENT BASIS FOR AREAS
REQUIRING REMEDIAL ACTION
Requirement for Definition of Source
Areas Candidate for Remedial Action
As discussed, the study area included several potential sources
of pesticides. However, the more extensive areas of residual soil
contamination (i.e., the orchards) are "typical" of much of Jef-
ferson County, since much of the land at one time supported or-
chards. In addition, this contamination did not result from
"disposal" activities normally associated with uncontrolled
hazardous waste sites. These factors emphasized the importance
of establishing a sound basis for definition of those areas can-
didate for remedial action. This basis was grounded in the follow-
ing:
• Comparison of contaminant levels within the study area as
well as with average agricultural levels reported in the litera-
ture
• Comparative risk assessment
RISK ASSESSMENT/DECISION ANALYSIS 187
-------
us
Orchards
10-122,600
7.720
20
,90-1.410
NR
Abandoned
Orchards
(Leetown)
9.186
ND
ND
ND
ND
US
Cornfields
100-4,050
NR
10
90
4
Suspected
Pesticide
Landfarn
(Leetown)
18
373
0.6
IS
0.9
The quantitative risk assessment formed a cornerstone in this
development and is discussed in detail in this section. Insight into
the actual decision-making processes employed by the U.S. EPA
in selecting the scope and extent of remedial action are discussed
in the following section.
Comparative levels of risk, particularly to human receptors,
were used to focus the study on actual areas of concern at the
Leetown Pesticide Site. The six source areas identified in the RI
were reduced to the three areas noted below that present the most
significant risk in excess of thai considered acceptable by the U.S.
EPA's decision-making process.
• Former Pesticide Pile Area
• Former Jefferson Orchard Pesticide Mixing Area
• Former Crimm Orchard Packing Shed
Atypically high areas of soil contamination were identified by
comparing source area contaminant levels and those normally
found in U.S. orchards or cornfields. Table 1 presents a com-
parison of site contaminant levels with literature values for
residual pesticide contamination in agricultural areas.
Table 1
Mean Pesticide Residue Concentrations In U.S. Soils'
Values Reported In ppb
Pesticide
DDT
toxaphene
aldrln
dleldrln
heptachlor
Note:
NR - Not Reported
MD = Sot Delected
Although DDT and its metabolites—ODD and DDE—were the
most pervasive and concentrated contaminants, the potential im-
pact of all of the detected pesticides was evaluated.
The three source areas noted above contained levels of DDT
that could be considered excessive. The pesticide pile soils con-
tained up to 416,000 ppb of DDT and its metabolites, while the
other two areas exhibited contamination levels between 22,000
and 96,000 ppb of these species. The orchards and the suspected
landfarm contained much lower levels of pesticides.
Levels of arsenic in the pesticide pile area (21 to 759 ppm) and
in the pesticide mixing area (23 to 110 ppm) exceeded the average
arsenic concentrations expected in orchard areas (110 ppm)1 and
in non-agricultural areas (7.4 ppm).1 The average lead concentra-
tion in soil is approximately 17 ppm; levels in the pesticide pile
reached 1,040 ppm, levels in the pesticide mixing area reached 328
ppm and levels in the soils near the packing shed reached as high
as 725 ppm.
Arsenic's potential carcinogenicity is the center of current
debate. It has been assigned a carcinogenic potency index by the
U.S. EPA Carcinogen Assessment Group (CAG). At the same
time, however, there is an acceptable level for arsenic in drinking
water (50 /ig/1). If the potency index were used to calculate the
risk from ingestion of water containing 50 /tg/1 of arsenic, it
would result in an incremental cancer risk of 1 in 50 (i.e., one ad-
ditional case of cancer in an exposed population of 50 persons).
Definition of an "acceptable" level of a carcinogen in drinking
water is somewhat contradictory, since carcinogens are, by defini-
tion, "non-threshold" chemicals (i.e., the occurrence of cancer is
not related to dosage). In any case, arsenic is thought to cause
only skin cancer by the oral and inhalational routes of exposure
and is not known to be dermally-absorbed in any form.*
Exposure Assessment
The site assessment process included a systematic evaluation of
potential or actual contaminant migration pathways, exposure
routes and populations at risk. Each of the potential source areas
was examined in light of public health and environmental risk.
Contaminant Migration Pathways
and Exposure Routes
Contamination in the pesticide pile area is confined to the sur-
face soils and will be released only when the soil is disturbed. The
most likely release mechanisms are erosion of soils by surface
water runoff or wind. Runoff could eventually carry con-
taminants to Bell Spring Run where they might accumulate and
magnify in the aquatic food chain. The carnivores at the highest
trophic level in the stream are creek chubs (Semoiilus
atromaculatus) and fallfish (S. corporalis), which are not con-
sidered gamefish. Thus, human exposure as a result of eating fish
from Bell Spring Run is unlikely. Fugitive dust from this area
could be carried off-site, exposing nearby residents.
Particulates could be emitted during tilling. Although the area
is currently in pasture, land use may change. Farmers could ex-
perience both dermal and inhalational exposures to pesticide-
laden particulates.
Soil disturbance is also the primary release mechanism for
DDT-con lamina ted soils in the mixing area and near the packing
shed. Both areas presently are well-vegetated, however, effective-
ly minimizing air and water erosion. The proximity of the pesti-
cide mixing area to Bell Spring Run may result in direct deposition
of contaminated soils in the stream during intense storms. As with
the pesticide pile area, this area could be tilled, thereby exposing
farmers to soil contaminants.
Activities in the former orchard areas and the suspected land-
farm area have some associated risks. Part of the former Jeffer-
son Orchard presently is used for production of silage corn, lead-
ing to an evaluation of the risk associated with ingestion of milk
from a local dairy. The orchards and the landfarm could add con-
taminated sediments to nearby streams. In addition, tilling these
areas could result in a human exposure to contaminants.
Exposure Coefficients and
Carcinogenic Risk Estimation
Once contaminant migration pathways and exposure routes are
defined, doses can be estimated and risks can be quantified.
Doses are determined by the amount of a contaminant that comes
in contact with a receptor's skin, lungs or gastrointestinal tract,
adjusting for bodily absorption. Conservative guidance on ab-
sorption is to use 100% unless another rate has been reported. A
dose in mg/day can be converted to a body dose by dividing the
dose by a representative body weight in kilograms (kg), thus pro-
ducing a dose in mg/kg/day. The following calculation is pro-
vided by way of example. Assuming:
• Residual pesticide concentration in soil of 0.5 mg/kg
• Ingestion of 1 mg/day during plowing
• Exposure rate of 10 days/yr for 40 yr
• An average lifetime of 70 (25,550 days)
• An average adult body weight of 70 kg
• Absorption rate of 100%
a dose can be calculated as follows:
(0.5 mq)(l x IP'6 ka)(10 days)(40 yr)(1.0)
fcg <<«y y
(70 kg) (2S.SSO days)
(1)
• 1.1 x 10'
'10
188 RISK ASSESSMENT/DECISION ANALYSIS
-------
Table 2
Exposure Coefficients Used at the Leetown Site
Exposure Route
Inhalation - Tilling
Inhalation - Fugitive Dust
Demi Contact
Ingestlon of Milk
Age
(Yr)
70
70
70
70
Body
Weight
(Kg)
70
70
70
70
Exposed
Surface
Area (o>2)
NA
NA
2948(7)
NA
Bloaccumulatlon
Factor
NA
NA
NA
0.7 (7)
Estimated
Exposure
Duration
10 day, 12 hr/day
for 40 yr
25 day/no, 10 ao/yr
for 70 yr
120 day/yr for 40 yr
70 yr
Absorption
Factor
0.75 (7)
0.75 (7)
0.10 (8)
1.0 (8)
Note: NA = Not Applicable
Table 3
Inhalations! Carcinogenic Risks from Tilling the Soil
Contanl nant
DDT/metabolites
alpha-BHC
beta-BHC
ganu-BHC
toxaphene
chlordane
aldrln
dleldrln
arsenic
TOTAL RISK
Pesticide
Pile
4.4 x 10'4
1.5 x 10 '4
3.5 x ID'7
5.4 x 10 -1
NO
NO
NO
ND
5.0 x 10-2
5.1 x 10-2
(1 In 20)
Pesticide
Mixing Area
4.3 x 10 '*
ND
ND
NO
NO
ND
ND
ND
1.7 x 10-2
1.7 x 10-2
(1 In 60)
Packing
Shed
5.7 x 10 '5
ND
ND
ND
ND
ND
ND
ND
4.4 x 10"3
4.5 x 10"3
(1 In 225)
Jefferson
Orchard
8.2 x 10"5
ND
ND
ND
ND
ND
ND
ND
ND
8.2 x 10'5
(1 In 12,000)
CM™
Orchard
2.9 x 10-5
ND
ND
ND
ND
ND
ND
ND
ND
2.9 x JO'5
(1 In 34,500)
Suspected
Landfarm
1.5 x 10"5
1.1 x 10"6
4.6 x 10 "8
1.6 x UP8
5.7 x 10'6
3.1 x UT7
2.2 x 10'9
1.5 x 10'7
2.8 x 10'3 *
2.8 x 10-3
(1 1n 360)
Notes:
ND = Not Detected during laboratory analysis
* = Due to arsenic at high concentration in one sample
This dose results in a dimensionless risk value when multiplied
by the carcinogenic potency factor, which has the units of kg-
day/mg. The potency factor converts a dose directly to risk using
a linear dose-response curve recommended for use by the U.S.
EPA.! The "linearized multi-stage" model is used as a conserva-
tive, upper-limit estimate of risk; that is, the true risk is not likely
to be higher than the estimate, but it could be considerably lower.
In this study, a worst-case estimate was presented, tempered by
reasonable exposure durations. However, risk estimates so de-
rived are very sensitive to the assumed factors in the dose estima-
tion calculations.
The probable incidence of adverse (carcinogenic) health effects
was estimated using the exposure scenarios presented in Table 2.
A total risk, according to U.S. EPA guidance for exposure to
multiple compounds, is the sum of the individual risks.6 This ad-
ditive model assumes that individual intakes are small, that there
are no antagonistic or synergistic effects between chemicals and
that all the chemicals produce the same health effect (in this case,
cancer). Cancer risks from various exposure routes also are ad-
ditive if the exposed populations are the same.
Total dermal risks to farmers calculated for all existing or
potential agricultural areas ranged from 6.6 x 10-7
(1/1,520,000) at the suspected pesticide landfarm to 5 x 10-5
(1/18,000) at the pesticide pile. Maximum and average risks were
calculated using the maximum and average contaminant concen-
trations, but the average risk is more representative of the ex-
posures incurred in tilling a large area. These dermal risk calcula-
tions do not include arsenic because arsenic is not dermally ab-
sorbed.
Table 3 is a typical risk summary chart, presenting the average
inhalational risks associated with tilling contaminated soils. In-
halational risks were somewhat higher than those associated with
dermal contact and served as the basis for development of the
target cleanup levels.
Fugitive dust blown from the plowed fields was a third po-
tential route of human exposure. Risks are generally much
lower than those for inhalation during tilling, except where ar-
senic is present. Estimated risks ranged from 1.2 x 10-10
(1/8,200,000,000) at the packing shed to 1.3 x 10-6 (1/770,000)
at the suspected pesticide landfarm, chiefly due to the greater
number of different types of pesticides found at the latter.
If lifetime milk consumption was from cattle grazing within the
watershed and feeding on silage and corn grain grown within the
study area, the additional risk of cancer would be approximately
1.3 x 10-4 (1/7,800). However, in actual practice, milk pro-
duced within the Bell Spring Run watershed is mixed with that
from other dairies at the local cooperative. Based on lifetime milk
consumption from the cooperative, the estimated risk is reduced
RISK ASSESSMENT/DECISION ANALYSIS 189
-------
to 9.9 x 10-8(1/10,000,000).
Establishment of Target Cleanup Levels
The risk assessment was used to develop target cleanup levels
for an engineering feasibility study of potential remedial alter-
natives using the same exposure scenarios and risk calculation
equations as described earlier, but solving for a soil concentration
by using a given risk goal such as 1 x 10-6 or 1 x 10~4. For ex-
ample, if Risk = (potency factor)(contaminant concentration)
(exposure coefficient), then contaminant concentration =
Risk
(potency factor)(exposure coefficient)
(2)
The resultant reduction in pesticide concentrations must be at-
tained during remediation. For every order of magnitude change
in desired risk, the soil concentration also will change by an order
of magnitude. This allows the U.S. EPA to set conservative ac-
tion levels to meet any desired residual risk. As an example, in
order to achieve a 1 x 10 ~6 incremental cancer risk at the three
areas subject to remedial action, pesticide levels would have to be
reduced to the following levels:
Contaminant
Pesticide Pesticide
Pile Mixing Packing
Area Area Shed
DDT/metabolites
alpha-BHC
beta-BHC
gamma-BHC
300
10
60
80
1.200 1,200
Note: All values in «ig/kg
—indicates thai these contaminants were not found ai these areas at concen-
trations requiring the establishment of action levels
Where more than one carcinogen is present in the soil matrix,
proposed residual soil concentrations for each contaminant must
be proportionally lowered. That is, if four carcinogens are present
in the soil and the desired residual risk is 1 x 10-', then the con-
centration of each contaminant must correspond to a risk of
1 x 10-6
or 2.5 x 10-7. This method assumes that the effects of all the
contaminants are equally harmful.
The only contaminant action level at this site that was not en-
tirely based on risk is that for arsenic. When risks were calculated
for inhalation of arsenic, it was found that a concentration of 7 to
10 mg/kg resulted in a risk of about 3 x 10-3. However, such
levels of arsenic can be considered normal for soils in the eastern
United States. Therefore, the target cleanup level for arsenic was
set at approximately 10 mg/kg, which is a reasonable background
level. It is not technologically feasible to remove arsenic to levels
that are below those found naturally.
DEVELOPMENT OF REMEDIAL
ACTION ALTERNATIVES
When developing alternatives to address a problem such as the
one at Leetown, or any other hazardous waste site, it is always ad-
vantageous to remember the objectives of the remedial action.
These objectives can be and should be discussed and agreed upon
long before the final data are received or before the feasibility
study begins to take shape. For Leetown, the remedial action ob-
jectives were developed in the final Leetown Pesticide Site Work
Plan' some 15 months before the selection of the remedial action
alternative. The objectives which molded the appropriate
responses to the contamination at Leetown called for:
". . . the determination of the remedial measures neces-
sary to mitigate the existing and potential impacts of con-
taminant migration on air, groundwater, surface water,
biota and soil resources in the vicinity of the site."
Based on these objectives and coupled with the information
and data from the remedial investigation, eight remedial action
alternatives were developed for the Leetown site:
No action
No action with monitoring
Consolidation with soil cover
Consolidationwith multimedia cap
On-site landfill
Off-site disposal
Off-site disposal with incineration
On-site treatment/off-site disposal
Each alternative would achieve the objectives as stated above
(except the no action alternatives which are required as a baseline
comparison) and would provide for the mitigation of potential
contaminant migration through the air and to the surface waters
in the affected area. With all of the environmental and health ob-
jectives addressed, the selection of the remedial alternative is
reduced to consideration of other factors such as costs, im-
plcmentability, institutional constraints and public opinion.
Issues in the Evaluation of toe
Remedial Action Alternatives
A discussion of the major issues unique to this site that in-
fluenced the selection of the final remedy at Leetown is provided
below.
Background Contamination
To better define the extent of the remedial action at Leetown,
the U.S. EPA had to establish a site-specific definition for "back-
ground contamination" and from there determine which areas fit
that definition. For this site it was determined that contamination
in the soil due to the normal application of pesticides on the or-
chard areas would be considered as background, while con-
tamination in areas of careless pesticide application (e.g., the
pesticide mixing area) and the dumping of contaminated material
not connected with the orchard operation (i.e., the former
pesticide pile area) would be considered the contaminated areas.
Acceptable Risks
By establishing background contaminant levels at this site, the
U.S. EPA did not ipso facto determine that any areas considered
as background were not to be considered in the final remedy. The
quantitative risk analysis for defined "background" areas had to
be reviewed and the concept of acceptable risk had to be dis-
cussed.
For example, by not taking any action in the former orchard
areas, the average inhalational carcinogenic risks (excluding
arsenic) for the exposure scenario as discussed earlier for the
former Jefferson and Crimm Orchards arc 8.2 x 10-s and 2.9 X
10-5, respectively. The U.S. EPA has determined in this case that
these risks, which were calculated from a very conservative ex-
posure scenario, were acceptable.
The decision to call these risks acceptable was considerably in-
fluenced by institutional factors and the consequences of the
potential precedent-setting decision that would have addressed
historical contamination due to normal application of pesticides
as hazardous waste activity subject to remediation. A decision by
the U.S. EPA to remediate the orchard areas would have set the
precedent of using Superfund monies to remedy a problem which
may well be very common in agricultural locations throughout the
190 RISK ASSESSMENT/DECISION ANALYSIS
-------
United States. If the U.S. EPA had determined the extent of
remedial action based solely on the exposure scenario risk calcula-
tions, it then would seem that almost all former orchard areas and
other agricultural use areas in this country would be candidates
for inclusion on the National Priorities List and eligible for Super-
fund cleanup.
This does not, in turn, establish the policy that any orchard or
agricultural area with similar pesticide concentrations would not
pose an unacceptable risk to potential targets. The potential ex-
posure scenario (chronic inhalation of dust from tilling) and the
likelihood of that scenario actually occurring had some influence
in determining acceptable risk. These decisions have to be made
on a site-specific basis.
Arsenic and Lead Contamination
The early orchard operators used lead arsenate as the pesticide
of choice, resulting in the occurrence of these two metals in the
soil. Table 4 shows that the arsenic and lead levels found in the
Robinson Property (non-disposal) areas are similar to those levels
found in the pesticide pile area and the mixing area. However,
Table 4
Arsenic and Lead Levels in Leetown Pesticide Study
(concentrations in /ig/kg)
Location
Avenge Detection •Adjusted
Concentration Frequency Average
Orchard background 10-53
(USFM Areas)
Orchard background 111-123
(Robinson Property Area)
Mixing Area 23-110
Pesticide Pile Area 21-759
location Pb Range
Orchard background 36-341
(USFM Areas)
Orchard background 474-991
(Robinson Property Area)
38
lie
62
137
7/7
2/2
3/3
IS/IS
41
116
62
98
Average Detection Adjusted
Concentration Frequency Average
Nixing Area
Pesticide Pile Area
104-328
44-1.040
209
732
199
304
7/7
2/2
3/3
15/15
217
732
199
267
Adjusted average obtained by eliminating the blgb and low sample concentration where signifi-
cant number of samples allow.
the average concentration of arsenic and lead found in the or-
chards that are now the USF&WS properties are somewhat lower.
This decrease is explained by the age of the orchard areas. The or-
chard that once occupied the Robinson Property area was the
older and more extensively used portion of the Jefferson Or-
chard. Therefore, the accumulation of lead arsenate is greater in
this area. However, the comparative risks associated with these
concentrations of arsenic and lead are within the same order of
magnitude across the study area. This exposure is unlike the risks
from DDT and its metabolites which were an order of magnitude
higher at the Robinson Property disposal areas than in the or-
chard background areas.
Therefore, it can be concluded that the levels of arsenic and
lead derived from historical lead arsenate spraying from
agricultural activities are somewhat consistent over the orchard
areas. On the other hand, the contrast of DDT levels and risks
between the disposal areas and the orchard background areas in-
dicates that the elevated levels of pesticides and other con-
taminants in the disposal areas were caused by non-agricultural
activities. In the pesticide pile area, the cause was dumping, while
in the pesticide mixing areas (including the packing shed) the
cause seems to be carelessly handling the pesticides.
To conclude, the same factors which eliminate the orchard
areas from remedial action (acceptable risks, exposure scenario,
historical contamination) also eliminate the need to remediate the
lead and arsenic contamination in the Leetown area.
Innocent Landowner Issue
Of particular interest in this investigation was another factor
which was discussed in the decision-making process—that of the
innocent landowner. As presently configured, all of the remedial
actions would take place on the Robinson Property where the
bulk of the contamination lies. A landowner is statutorily a
responsible party. However, in the present case, the Robinsons
may be considered victims of a "midnight dumping" episode in
which the land lessor dumped in the area which is now the former
pesticide pile location.
Selection of any alternative which incorporated on-site storage
of the contaminated soils would negatively impact future use (and
value) of the property. The off-site disposal alternatives and the
on-site treatment options would only require a short-term (2 years
maximum for on-site treatment) reservation of land. Again, it is
stressed that this is only a small variable in the overall decision-
making process of selecting the final remedial alternative.
Selection of the Remedial Action Alternative
The remedy selected to address the pesticide contamination at
the mixing area locations and the former pesticide pile area in
Leetown was the on-site treatment option. This alternative would
be designed to eliminate DDT and other pesticide contamination
by microbial degradation.
Destruction of this waste on-site is a desirable alternative since
it eliminates potential exposure to DDT and its metabolites from
future tilling operations in the area. In addition, this option re-
quires only a temporary dedication of lands in the site vicinity for
treatment of wastes. Waste transport from the source areas over
public roads is limited, and no hazardous waste disposal capacity
at an off-site RCRA-approved facility is necessary. The key provi-
sion in the selection of this remedy is the destruction of the
wastes. This "treatment" of hazardous contamination is consis-
tent with recent U.S. EPA policy and guidance on selecting an en-
vironmental remedy at a Superfund site. The U.S. EPA's Off-site
Disposal Policy10 states:
"It is EPA's policy to pursue response actions that use
treatment, reuse or recycling, over land disposal to the
greatest extent pratticable . . . and when recommending
and selecting the appropriate remedial action, treatment
reuse or recycling may be found more protective of public
health and the environment than land disposal."
In addition, recent interim guidance from the U.S. EPA en-
courages the consideration of treatment technologies and gives
guidance on how to approach the issue of cost-effectiveness of
treatment operations over a long-term period.
Finally, the preamble to the National Contingency Plan states
that higher-cost alternative technologies can be selected when
treatment or destruction offers a permanent solution to en-
vironmental contamination.
REFERENCES
1. NUS Corporation ."Draft Remedial Investigation Report - Leetown
Pesticide Site," NUS Corporation, Pittsburgh, PA, 1986.
2. Edwards, C.A., Ed., Persistent Pesticides in the Environment, 2nd
edition, CRC Press, Cleveland, OH, 1973.
3. Shacklette, H.T. and Boerngen, J.G., "Element Concentrations in
Soils and Other Surficial Materials of the Conterminous United
States," U.S. Geological Survey Professional Paper 1280, Wash-
ington, DC, 1984.
RISK ASSESSMENT/DECISION ANALYSIS 191
-------
4. U.S. EPA, "Health Assessment Document for Inorganic Arsenic,"
Office of Health and Environmental Assessment, Washington, DC,
EPA-600/8-83-021F, 1984.
5. U.S. EPA, "Proposed Guidelines for Carcinogen Risk Assess-
ment," Federal Register 49, Nov. 23, 1984, 227.
6. U.S. EPA, "Proposed Guidelines for the Health Risk Assessment
of Chemical Mixtures and Request for Comments," Federal Register
50, Jan. 9, 1985, 6.
7. Schaum, J., "Risk Analysis of TCDD-Contaminated Soil," Ex-
posure Assessment Group, Office of Health and Environmental
Assessment, U.S. EPA, Washington, DC, EPA-600/8-84-031,1984
8. McLaughlin, T., "Review of Dermal Absorption," Expoiure As-
sessment Group, Office of Health and Environmental Assessment
U.S. EPA, Washington, DC, EPA-#»/8-84-033, 1984.
9. NUS Corporation, "Final Remedial Investigation/Feasibility Study
Work Plan-Leetown Pesticide Site," 1984.
10. U.S. EPA, EPA Offsite Disposal Policy, U.S. EPA, Washington
DC, May 6, 1985.
192 RISK ASSESSMENT/DECISION ANALYSIS
-------
Innovative Use of Toxicological Data to Improve
Cost-Effectiveness of Waste Cleanup
Todd W. Thorslund, Ph.D.
Gail Charnley, Ph.D.
Elizabeth L. Anderson, Ph.D.
ICF-Clement Associates
Washington, D.C.
ABSTRACT
A new approach for estimating the total cancer risk associated
with given exposures to multiple polynuclear aromatic hydrocar-
bons (PAHs) has been developed. This approach is based upon
two important methodological improvements. First, a mathemati-
cal dose-response model that incorporates the most advanced
understanding of the carcinogenic mechanisms of action of PAHs
was generated for benzo[a]pyrene (B[a]P). The parameters in this
model were estimated for both ingestion and inhalation of B[a]P.
Second, the open literature was surveyed for data from car-
cinogenesis bioassays in which B[a]P and other PAHs were tested
simultaneously in the same test system. Based on the assumption
that the functional form of the theoretical dose-response model
for B[a]P is applicable to the other PAHs, relative potency
estimates were obtained from each of the relevant studies.
A dose-response model for joint exposure to multiple PAHs
was generated, using the relative potency estimates and the B[a]P
theoretical model functional form. An example of the total risk
associated with exposure to multiple PAHs-was given to illustrate
how cancer potency estimates can be modified to obtain a more
cost-effective remedial solution. Also discussed are the conditions
under which the U.S. EPA and other Federal and state regulatory
agencies would be likely to accept this approach to improving
cost-effectiveness of waste cleanup.
INTRODUCTION
Most regulatory decisions have specified that the total risk to
an individual exposed to carcinogens at a Superfund site must be
controlled to fall within a target range of 1 x 10-4tol x 10-7.
This goal is to be achieved through the development of remedial
actions that reduce uncontrolled exposures to levels that lie within
the target risk range.
Designing cost-effective remedial measures to reduce exposure
to multiple potential carcinogens is a complex legal, engineering
and lexicological problem. Virtually all proposed remedial solu-
tions treat the carcinogen potency factors as rigid physical con-
stants. A far more cost-effective approach often may be achieved
by incorporating improvements in the toxicological data base and/
or carcinogenic dose-response models into the remedial solution.
Such an approach is consistent with the U.S. EPA policy of up-
dating the cancer potency numbers whenever there is sufficient
scientific evidence that changes would improve the estimate. At
present, a number of the models used to estimate the cancer
potency factors used in Superfund public health evaluations do
not make best use of available information. Time and/or resource
constraints imposed in the development of the cancer potency
value and subsequent expansion of the knowledge base are the
prime reasons for the sometimes inadequate cancer potency
estimates presently in use.
B[a]P traditionally has been used by the U.S. EPA as the in-
dicator of the carcinogenicity for those PAHs suspected of being
carcinogens. Many states have followed suit. However, it is
known that B[a]P is one of the most potent carcinogens of the
polycyclic organic family. It may, in fact, be as many as three
orders of magnitude more potent than some of the other
suspected PAH carcinogens. It is therefore possible to hypothe-
size that, if mathematical models based upon relative potency
estimates of PAHs compared to B[a]P were developed to estimate
the joint risk of the total exposure, carcinogenicity estimates
might be reduced considerably.
This approach has been used successfully in the past. A
relative potency approach for estimating risk associated with
PAHs in diesel exhaust has been obtained. This approach avoids
the over-estimation of risk by the use of B[a]P as a surrogate for
these PAHs.1 A National Academy of Science oversight commit-
tee developed the approach, and it has been accepted by the U.S.
EPA as the most appropriate for characterizing the potency of
PAH mixtures from diesel emissions. In addition, long-term in-
halation bioassays are now being completed at the Lovelace
Laboratories, and the results support the comparative potency
approach developed earlier. We believe that a similar approach
for estimating joint PAH risk from other sources is a highly credi-
ble alternative to the current system.
In this paper, new state-of-the-art dose-response models are de-
rived for B[a]P for both ingestion and inhalation exposures.
Values for the relative potency of various PAHs compared to
B[a]P are estimated using the new dose-response model and ap-
propriate carcinogenicity studies from the literature. By combin-
ing this information, a dose-response model for joint exposures to
PAHs is generated. Finally, we discuss the factors that would in-
crease the probability of acceptance of this and other innovative
approaches by the regulatory agencies, and we offer arguments
for the cost-effectiveness of such approaches.
DEVELOPMENT OF A MATHEMATICAL
CANCER RISK MODEL
Advances in the estimation of the cancer risk associated with
exposure fo B[a]P within the framework of the available data
base are dependent upon improvements in dose-response model-
ing. In this report, new approaches to cancer risk modeling are
reviewed, and a general model is recommended. A special case of
this general model is developed based on the postulated mechan-
ism of action of B[a]P, and the information that is consistent with
this hypothesis is noted. Finally, the postulated model is fitted to
the available cancer dose-response data on the effects of ingesting
or inhaling B[a]P.
RISK ASSESSMENT/DECISION ANALYSIS 193
-------
Multistage Models
Multistage and related mathematical models of carcinogenesis
have evolved over the past 30 years. Comprehensive reviews of the
development of these models through the late 1970s are found in
articles by Whittemore1 and Whittemore and Keller.' In recent
years, advances in the understanding of the mechanisms of car-
cinogenesis have been incorporated into more realistic variations
of multistage mathematical models. Notable in this regard is the
two-stage model that takes into account the proliferation of in-
itiated, first-stage cells. This model is discussed in detail in
Moolgavkar and Venzon,' Moolgavkar and Knudson,' and Mool-
gavkar.6 Thorslund el al.1 have extended the two-stage model to
incorporate the effects of environmental agents on cell transition
rates, first-stage cell proliferation rates and cell death rates. In its
general form, the model may be written as:
P(x,t) = |-exp - M[l + (I +
- 1 - G(x)t)/G(x)2
+ Sx)(exp[O(x)t)
(1)
where:
S
S + l
M
x
is the smallest relative transition rate,
is the largest relative transition rate,
is a scaling factor,
is a constant lifetime exposure of the reactive
form of the agent at the molecular or cellular site
of action,
t is the age at which the risk is evaluated, and
G(x) is the exposure-dependent growth rate of the
first-stage, i.e., preneoplastic cells.
In the next section, the rationale for using a specific form of this
model for B[a]P is explained.
Dose-Response Model for B|a)P
One simple form of the B[a]P dose-response model is based on
two assumptions: (1) that both transition rates are the same linear
function of dose x, (2) and that the growth rate of preneoplastic
cells is independent of the exposure level. As Moolgavkar'
pointed out, such a situation would occur when two genes on
homologous chromosomes that regulate cell growth experience
critical point mutations, which would reduce the controls on
growth. If these point mutations are linear functions of dose, the
dose-response relationship may be expressed as:
P(x,t) = 1 -exp - M( 1 + Sx)2[exp(Gt) - 1 - Gt]/G2 (2)
which reduces to the form:
P(x) = l-exp[-A(l+Sx)2] (3)
if the time of observation is assumed to be constant across all ex-
posure groups.
This model, in its various forms, has a number of advantages.
Among the most important are the following:
• At low doses, the models converge to a linear, no-threshold
form;
• It can be used to adjust for different lengths of observation
among exposure groups;
• The time-independent form of the model has only two parame-
ters that have to be estimated, so that goodness-of-fit tests can
be run on the data from the standard bioassay with one con-
trol and two exposure groups;
• A stable point estimate of risk can be obtained directly;
• The mathematical form of the model follows directly from the
most widely accepted hypothesis of the mechanisms of cancer
induction.
Rationale for Using the Model: Mechanism of
Tumorigenesis for Benzo[a]pyrene
B[a]P is metabolized by the cytochrome P450 microsomal
mixed-function oxidase system to a number of hydroxylated
derivatives that are generally conjugated as glucuronide, sulfate
or mercapturic acid compounds. Sims et a/.' noted that the in-
trinsically active form of B[a)P responsible for its covalent bind-
ing to DNA is the 7,8-diol-9,10-epoxide; it is generally accepted
that this metabolite is responsible for the tumorigenicity of B(a]P
(IARC 1983). Covalent binding of reactive metabolites of B[a]P
and other carcinogenic PAHs to DNA appears to be an essential
step in the production of PAH-induced neoplasia.910 If the ad-
ducts are not repaired, replication of damaged DNA during cell
proliferation may lead to mutation. The induction of neoplaiu
thus is related both to the extent to which PAHs bind to DNA and
to the level of cell proliferation in the target tissue.
Pereira et al.n applied single doses of B[a]P topically to ICR/
Ha mice and found a linear relationship between the applied dose
and the amount of each of the two major B[a]P-DNA adductj
formed in the epidermis over a dose range of 0.01 to 300 mg of
B[a]P/mouse. The level of adduct reached a maximum after 7 hr
and remained constant for the next 49 hr, indicating that repair of
such lesions is slow.
Adriaenssens el al.n administered single doses of B[a]P orally
via intubation to rats and examined the formation of DNA ad-
ducts over a dose range of 2 to 1,351 umol/kg (0.048 to 29.7
umol/mouse). The rate of formation of the major diol epoxide-
DNA adduct was linear with respect to dose in the forestomach.
Although the authors state their results show no linear relation-
ship between dose and adduct formation in the lung, we contend
the extent of the deviation from linearity is so slight that such a
relationship may indeed have existed.
B[a]P metabolites bind to DNA in every tissue that has been ex-
amined, regardless of species, dose or route of administration.
Adducts tend to be persistent and are similar both qualitatively
and quantitatively in various tissues, whether or not the tissue is a
target for cancer.13 Thus, formation of an adduct to DNA is a
necessary step in B[a]P-induced carcinogenesis, but other factors
also may be involved. If target tissues have higher rates of cell
proliferation than other tissues, it may be postulated that these
tissues have a greater probability of fixing a mutation following
adduct formation than tissues with lower rates of proliferation.
In an extensive series of skin-painting studies in mice, it has
been shown that the tumor dose-response relationship is
quadratic in form,'-1 even though the DNA-B[a]P adduct forma-
tion in mouse skin is linear at the same levels. This seeming con-
tradiction is exactly what we would predict on the basis of the
model suggested here if background tumor and mutation rates
were low.
Because the evidence strongly suggests that B[a]P is a genotoxk
agent acting at two sites on DNA, the two-stage model with equal
transition rates is a useful approach for estimating the cancer risk
associated with exposure to B[a]P In the next two sections, the
restricted two-stage model is fitted to dose-response data for ex-
posure to B[a]P via both ingestion and inhalation.
Dose-Response Relationship for
Oral Exposure to B(a]P
The carcinogenicity of B[a)P via ingestion was investigated in a
series of experiments conducted by Neal and Rigdon15 and by
Rigdon and Neal16'17. The most pronounced dose-response rela-
tionship, obtained under reasonably consistent conditions, was
observed in the Neal and Rigdon" study. The results of this ex-
periment are reproduced in Table 1. The type of carcinogenesis
induced in this study was either a papilloma or a squamous cell
carcinoma in the squamous portion of the stomach.
Neal and Rigdon" employed a number of experimental factors
that are atypical of the standard bioassay protocol in the Iw*
study, including a variable age at first exposure, a duration of «•
194 RISK ASSESSMENT/DECISION ANALYSIS
-------
Table 1
Gastric Tumors in Mice Fed Benzo[a]pyrene
Age first
exposed
(days)
30
30
116
33-67
33-101
31-71
17-22
20-24
18-20
49
56
49
62
49
91
74
48
98-180
Milligrams
of B[a]P per
gram of food
0.0
0.001
0.01
0.02
0.03
0.04
0.045
0.05
- 0.10
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.10
0.10
5.0
Number
of days
fed B[a]P
110
110
110
110
110
110
107-197
98-122
70-165
1
2
4
5
7
30
7
30
1
Age killed
(in days)
300
140
140
226
143-177
143-211
141-183
124-219
118-146
88-185
155
162
155
168
155
198
182
156
209-294
Number with
gastric tumors
Number of mice
0/289
0/25
0/24
1/23
0/37
1/40
4/40
24/34
19/23
66/73
0/10
1/9
1/10
4/9
3/10
26/26
0/10
12/18
17/33
Source: Adapted from Neal and Rigdon"
posure that only lasted about one-fifth of a lifetime and an obser-
vation period that was less than one-third of a lifetime.
Syracuse Research Corporation (SRC), under contract to the
U.S. EPA, had only limited resources to devote to developing a
unit risk estimate for B[a]P. They therefore decided to use the
Neal and Rigdon15 study, but to restrict the data set to that
subgroup of the experimental population that had been exposed
continuously throughout the experiment. In fitting the multistage
model, no adjustments were made for the variable length of the
follow-up period or for the age attained at the end of the observa-
tion period. Using the standard U.S. EPA approach discussed in
Anderson et a/.,18 SRC discarded all data on animals exposed to
50 ppm B[a]P or more because of "lack of fit" and obtained an
upper-bound estimate on the chemical's potency to humans of
11.53(mg/kg/day)-i
If more detailed data were available on the age at first exposure
and on the length of exposure for individual animals rather than
data on exposure groups as a whole, a more precise, time-
adjusted analysis would be possible. Because such detailed infor-
mation is lacking, however, the approach taken here is to restrict
the analysis to exposure groups that are comparable with respect
to age at exposure and number of days exposed. The resulting
homogeneous experimental subpopulation, selected from the en-
tire experimental population (Table 1), is presented in Table 2.
This is the same subgroup used by Chu and Chen,19 two members
of the U.S. EPA's Carcinogen Assessment Group (CAG), in a
paper presented at the Pacific Rim Risk Conference.
Table 2
Data Used to Estimate the Dose-Response Relationship
Between Ingested B[a]P and Gastric Tumors
Dose
(ppm in diet)
0
1
10
30
40
45
Dose (x)
(rag/kg/day)
0.00
0.13
1.30
3.90
5.20
5/85
Number of
mice with
gastric tumors
Number Exposed
0/289
0/25
0/24
0/37
1/40
4/40
Expected number
of tumors pre-
dicted by model
0.50
0.05
0.20
1.32
2.25
2.72
Note: This table contains data on only those groups that are comparable with respect to age when
first exposed and number of days exposed. The first three columns are from Neal and Rigdon."
The fourth column is based on the two-stage, dose-dependent, time-independent, identical transi-
tion rate model:
P(x) = 1 - exp [-0.0017256(1 + 0.922x)2]
The two-stage model with identical linear dose-dependent tran-
sition rates was fitted to the data in Table 2. The joint maximum
likelihood estimates of the parameters are indeterminate, with
A > 0 and S *» oo. One way around this problem is to ob-
tain a positive estimate for "A" using a different method. Based
on a priori biological assumptions, we know that A > 0. This
follows from the fact that if one assumes that B[a]P exerts its ef-
fects via a direct genotoxic mechanism of action, the background
tumor rate is proportional to the square of the mutation rate
caused by factors other than B[a]P at the critical gene locus.
Because a variety of other factors, such as background levels of
PAHs, viruses and solar irradiation, have the potential to induce
such mutations, a nonzero background tumor rate estimate is re-
quired for biological consistency. Unfortunately, the "maximum
likelihood" estimate of the background tumor rate is zero, (i.e.,
0/289 = 0). We have chosen to use a Bayesian estimator with an
invariant prior. This approach has been suggested by Jeffreys20
and by Gart,21 among others, in comparable situations where it is
known a priori that a zero estimate is unlikely.
Using this approach, the background tumor rate is estimated
to be:
P(0) = 0.5/(n + 1) = 0.5/290 = 0.0017241
(4)
Equating this value to the parametric form of the two-stage, dose-
dependent, identical transition rate model yields the following
relationship:
P(0) = 0.0017241 = 1 - exp[-A(l + S-0)2] = 1 - exp(-A) (5)
which may be solved directly for A. The solution is A =
0.0017256, which is put into the model equation to obtain the
relationship:
P(x) = 1 - exp[-0.0017256(1 + Sx)2]
(6)
The remaining unknown parameter, S, is then estimated by fit-
ting the equation above to the data in Table 2. An approximate
maximum likelihood estimate of 0.922 is obtained. The model's
goodness of fit is also shown in Table 2. The expected values are
too small to conduct a formal X2 goodness-of-fit test. However, it
is apparent that the model is not underestimating the tumor rate
in the experimental range.
The low-dose linear term from this model may be expressed in
terms of the parameter values as 2AS, which must be greater than
zero because the background rate A is always greater than zero
and S is greater than zero for all positive dose-response relation-
ships. The low-dose linear term in animal exposure units
(mg/kg/day) for a 140-day (30 + 110) experiment is thus
q, = (2)(0.001723)(0.922) = 0.00318 (mg/kg/day)-1
(7)
Two adjustments are necessary to translate this into a human
potency value. First, the risk must be adjusted to take into ac-
count constant exposure throughout one's lifetime. It is assumed
that 1.5 mice years equal 70 human years (i.e., a lifetime) and 1.5
mice years)(365 days/year) = 548 days. The U.S. EPA's standard
procedures for less than full lifetime followup yield an ad-
justment factor of (548/140)3 = 59.97. Second, it is standard
practice to calculate species-equivalent exposure units on a mg/
surface area basis. To convert our estimate to these units, we
multiply by the additional adjustment factor of (60/0.034) '/* =
12.08, where 60 and 0.034 kg are the weights of an average human
and CFW mouse, respectively. After making these two ad-
justments, the human potency factor is estimated to be:
qi = (0.00318)(59.97)(12.08) = 2.30 (mg/kg/day) -1 (8)
for human exposure. This value can be compared to the 95%
upper-bound estimate of 11.53 (mg/kg/day) -1 obtained by the
U.S. EPA's contractor, which is not an actual estimate; it is only
RISK ASSESSMENT/DECISION ANALYSIS 195
-------
the upper-bound estimate of the actual values and is approximate-
ly five times greater than the linear point estimate obtained here.
Dose-Response Relationship for
Inhalation Exposure to B[a]P
Studies conducted to assess the risk of cancer posed by airborne
B[a]P tend, for obvious reasons, to employ inhalation as the
route of exposure. Such studies, however, face difficult methodo-
logical problems. Intratracheal instillation of B[a]P alone or in
combination with other agents is therefore often substituted for
inhalation. Although much valuable qualitative information has
been obtained by this approach, its use in quantitative risk
assessments has not met with much success.
Most carcinogenesis bioassays in which B[a]P has been ad-
ministered via inhalation exposure have yielded negative results.
There are several exceptions. Most notably, a positive response
was obtained in rats using a combination of B[a]P and the at-
mospheric irritant sulfur dioxide; sulfur dioxide by itself was not
carcinogenic.22 The tumors induced in this experiment were
squamous cell carcinomas; a proportion of the bronchogenic car-
cinomas found in humans are of this type.
A well-conducted study by Thyssen el al.u provides the most
clearcut evidence of the dose-response relationship between in-
haled B[a]P and tumorigenesis. In this experiment, Syrian golden
hamsters were exposed throughout their lives to B[a)P by means
of a sodium chloride aerosol for 4.5 hr per day, 7 days/week, for
10 weeks and for 3 hr/day thereafter. Respiratory tract tumors
were induced in the nasal cavity, larynx and trachea. The dose-re-
sponse relationship obtained for these tumors is shown in Table 3.
Table 3
Data Used lo Estimate Dose-Response Relationship Between
Inhaled B|a]P and Respiratory Tract Tumors
Exposure
rate (x)
(mg B(a)P/m3)
0
2.2
9.5
46. 5
Average
survival (t)
(in weeks)
96.4
95.2
96.4
59.5
Effective
number
exposed
27
27
26
25
Number of
tract
Predicted
0.73
1.88
9.06
12.59
respiratory
tumors
Observed
0
0
9
13
Note: Based on two-stage, dote- and time-dependent, identical transition rate model:
P(x.i) = l-expl-O.OOOII5(l+0.3l2»)2)|ejtp<0.057l)-l-0.057l)
Source: Thyuen el al."
Using the average survival time as the length of observation, the
two-stage model with identical transition rates and variable at-
tained ages was fitted to the observed data using an approximate
method. The goodness of fit is demonstrated in Table 3, where a
x* of 2.81 with 1 =(4-3) degree of freedom is obtained, which
implies that the observed data are not inconsistent with the model
at the p > .05 level. The risk at the end of an average lifetime was
obtained from the equation shown in Table 3 by evaluating P(x,t)
at t = 96.4 weeks, the average survival time in the control popula-
tion. This gives the following time-independent lifetime risk rela-
tionship:
P(x) = 1 -exp[- 0.0272(1 +0.312x)2] (9)
For low levels of exposure, the linear term of the model times the
exposure level is a close approximation of the estimated risk. The
linear term in this case may be expressed as:
q, = (2) (.0272) (0.312) = 0.0170 (mg B[a]P/m3]-1 (10)
To extrapolate this value to exposure by humans for 24 hr/day,
the average length of exposure per day over the approximate 2-yr
experimental period is calculated. The weighted mean of the two
exposure periods is:
1(10) (4.5) + (92)(3)]/102 = 3.147 hr/day. Thus, exposure 24 hrA
day renders a potency value of:
q, = (0.0170) (24/3.147) = 0.1295 (mg B[a]P/m3]-l (jj)
This calculation is based on the assumption that inhalation ex-
posures are equivalent across species. To convert this exposure
level to (mg/kg/day) - > so as to compare it to exposure via inges-
tion, we assume that the absorption rates for inhalation and jn.
gestion are the same and that the average person weighs 70 kg and
inhales 20 m* air per day. Under these assumptions, exposure to 1
mg/m^ for 24 hr results in an exposure level of 1*20/70 = 0.2857
mg/kg/day. Thus, on a mg/kg/day basis, the estimated slope ii:
q, = 0.1295/0.2857 = 0.4533 (mg/kg/day) - 1 (12)
This value is considerably smaller than the U.S. EPA's estimate
of 6.1 1 (mg/kg/day)- '. which is based upon an adjustment for
difference in species metabolism that is questionable.
The next section describes the model that was developed to
estimate relative carcinogenic potencies for mixtures of PAHs.
ESTIMATION OF THE JOINT
CARCINOGENIC RESPONSE OF THE
TOTAL PAH EXPOSURE
The relative potency of the jth carcinogenic PAH compared to
the potency of B[a)P at response level is defined as:
Rj(p) = x(p)/yj(p) (13)
where x(p) and y}(p) are the number of exposure units of B|a]P
and the jth carcinogenic PAH, respectively, required to produce a
total carcinogenic response rate of p in the test system.
If the mechanism of action of B[a]P is the same as that of the
jth carcinogenic PAH, it follows that:
Rj(p) = Rj (H)
(i.e., the relative potency is independent of the response level).
This assumption is identical to the hypothesis of simple similar ac-
tion24 which often is used to estimate the joint response to multi-
ple agents for various biological end points.
Under the hypothesis of simple similar action, it follows direct-
ly that the joint response to a set of carcinogenic PAHs is depen-
dent upon the total PAH exposure, T, expressed in B[a]P
equivalent units. This exposure may be written as:
T = £
. J •'
where:
m
+ x
(15)
= the total number of indicator PAHs exclusive of
BlaJP,
yj = the exposure to the jth indicator PAH,
x = exposure to B[a]P, and
RJ = relative potency of the jth indicator PAH com-
pared to B[a]P.
The probability of a cancer response given T is P(T), where P(0 is
the dose-response relationship for B[a]P.
It was shown that the same functional relationship is consistent
for the dose-response to B[a]P in mouse skin via skin-painting,
hamster lung via inhalation and mouse stomach via ingestion.
Given this demonstrated experimental consistency and the under-
lying theoretical rationale for the mechanism of action of the
PAHs, it is reasonable to assume that the same functional rela-
tionship exists for all animal test models. The parameter estimates
would undoubtedly be species-tissue-dependent, but the under-
196 RISK ASSESSMENT/DECISION ANALYSIS
-------
lying structural relationships should be the same.
Using the two-stage identical transition rate model developed
for B[a]P, the dose-response relationship for a specified test
system can be expressed as:
P(x) = 1 - exp - A(l + Sx)2 (16)
for B[a]P and as:
Pfy) = 1 -exp-A(l + SRjyj)2 j = 1,2,. . ., m (17)
for the carcinogenic PAHs.
It is possible to obtain 100% efficient estimates of the Rj values
by joint maximum likelihood estimation. However, such estima-
tion procedures are time-consuming to develop and lie beyond the
scope of the present project. Fortunately, a simple approximation
for the estimates of the Rj values can be obtained.
We first estimate the value A from the control data. It can be
shown that the final potency estimates are not particularly sen-
sitive to this estimate. Given the estimated value of A, the terms
SR; can be estimated by an approximate goodness-of-fit pro-
cedure for each PAH for which data are available. The parameter
S is estimated in a comparable manner using B[a]P dose-response
data. The final relative potency estimates for Rj, which are in-
dependent of the animal test system used, are obtained from the
ratio of the estimates for SRj and S, determined from the jth
PAH and B[a]P, respectively.
For many test systems, the highest dose may be the least rele-
vant for determining potency, because of its association with
acute toxicity, activation of cell proliferation mechanisms and/or
saturation of metabolism or local penetration. When the highest
dose yields a level that is inconsistent with the assumed dose-
response model, it will not be used in estimating the parameters.
In other situations, only a single dose level for B[a]P may be
available. In this case, if B[a]P gives a high response, a more
stable estimate may be obtained by simply using the PAH ex-
posure level that gives the closest response rate to that of B[a]P.
Even when a control value and a single response for B[a]P and the
jth carcinogenic PAH are the only values available, it is possible
to obtain an estimate of the relative potency. To demonstrate how
such estimates can be obtained, consider the following limited
response data.
Table 4
Observed Rates
Agent
Exposure Response
Control
B[a]P
jth PAH
0
x
r/n
rj/nj
An estimate for the relative potencies can be obtained by
equating the observed rate with the function response. This
results in the equations:
r0/n0= 1-exp-A (18)
r/n = 1 - exp - A(l + Sx)2 (19)
rj/nj = 1 -exp-A(l + SRjyj)2j = 1,..., m (20)
which can be solved algebraically by hierarchical substitution of
the parameter estimates for A and S into the equation defining the
relative potencies. This approach yields the algebraic solution:
D _ X
Rj- —
In the next section, the relative potency values (Rj) are
estimated for chemicals expected to be present at waste sites. We
also present an example of the extent to which estimates of risk
can differ using the new method compared to the U.S. EPA's
standard approach.
COMPARATIVE POTENCY ESTIMATES
The number of quantitative evaluations of the carcinogenicity
of PAHs in comparison to B[a]P is somewhat limited. In the
studies that have been selected to form the basis for comparative
potency estimates, B[a]P was tested in the same bioassay system
as the other PAHs in the same, laboratory and at the same time.
The following table lists the comparative potencies that have been
derived in several studies for a number of PAHs commonly found
at environmental waste sites.
Table 5
Summary of Relative Potency Estimates Derived for Indicator PAHs
Benzo[a]pyrene 1.0
Benz[a]anthracene 0.145C
Benzo [b]fluoranthene 0.140*
Benzo[k]fluoranthene 0.066a
Benzo [ghijperylene 0.022a
Chrysene 0.0044^
Dibenz[ah]anthracene 2.82b
Indeno[l,2,3-cd]pyrene 0.2323
References:
a. Deutsch-Wenzel et al."
b. Pfeiffer"
c. Bingham and Falk"
d. Wynder and Hoffmann"
The following example illustrates how cancer risks due to ex-
posure to a mixture of PAHs can be estimated using comparative
potencies or using the standard U.S. EPA upper-bound ap-
proach.
Assume that an individual was exposed via inhalation to the
mixture of PAHs given in the following table.
Table 6
Results of Cancer Risks from PAH Exposure
PAH
Benzo[a]pyrene
Chrysene
Dibenz [ah] anthracene
Benzo[k]fluoranthene
Benzo [b]fluoranthene
Benz[a]anthracene
Total
Exposure level
mg/kg/day
W
0.0012
0.0105
0.0001
0.0010
0.0010
0.0014
0.0152
Relative
potency
(Rj)
1.0000
0.0044
2.8200
0.0660
0.1400
0.1450
BMP
equivalent
units (Rjx)
0.00120
0.00005
0.00028
0.00007
0.00014
0.00020
0.00194
Using the upper-bound approach, an estimate of risk is obtained:
6.11 x 10-3 x .0152 = 9.3 x 10-5 (22)
Using the alternative point estimate, the risk is estimated to be: •
(23)
.453 x 10-3 x .00194 = 8.8 X 10-7
[In(l-r/n)/ln(l-ro/n0)]^ - 1
j = 1,2, . . ., m (21)
or more than two orders of magnitude lower. In this example, the
upper-bound approach would probably cause regulatory concern;
the point estimate would most likely not trigger remedial action.'
RISK ASSESSMENT/DECISION ANALYSIS 197
-------
OBTAINING REGULATORY ACCEPTANCE
OF A NEW APPROACH
Estimates of the risk of exposure to carcinogens are based upon
a series of conservative assumptions chosen to protect human
health. When information is limited, parameter values are chosen
conservatively to ensure that their incorporation in a risk model
does not lead to an underestimate of risk. However, when actual
data are available that can be used to measure a parameter direct-
ly, this information can be supplied as an alternative to the upper-
bound assumption. Such improvements in precision usually result
in a lower upper-bound risk. As a general rule, as the scientific
depth of the knowledge base increases, risk estimates based upon
that knowledge decrease for the same assumed exposure level.
This concept is illustrated in Fig. 1. Nevertheless, just because an
improved model has been developed does not mean that it will be
adopted by highly precedent-bound regulatory agencies. Often,
new approaches must be sold to the regulatory agency through
such mechanisms as:
• Outside review by prestigious unbiased review committees
• Presentations at scientific meetings
• Publication in the peer review literature
• Formal and informal meetings and seminars with regulatory
personnel
The relationships among such effort, the quality of the study
and the effort expended in gaining acceptance are depicted in Fig.
2. Efforts expended in this direction can give a highly profitable
return on the investment when the potential savings in remedial
action are considered. A reduction in risk of one order of
magnitude brought about by improvements in risk assessment
methodology can lead to a 100-fold reduction in cleanup cost.
The benefit-to-cost ratio for such an approach can be very large.
Although generating extensive new biological information is cost-
ly, undertaking the kind of cleanup activities that might be recom-
mended based on the upper-bound dose-response modeling ap-
proaches is even more costly. The general relationship between
total cost of effort and risk is depicted in Fig. 3.
Figure 1
Relationship Between Improvements in Mathematical
Dose-Response Model and Estimated Risk
CONCLUSIONS
Biological parameters used in quantitative risk assessments
should not be treated as fixed physical constants; rather, they
should be viewed as crude approximations that can be altered by
more extensive analysis and experimentation. Such effort usually
will result in a reduction of perceived risk and a potentially large
saving in remedial action costs. One example of where such an ap-
proach could result in considerable savings is in sites where ex-
fW
Proboblllly
(PA Adopll
Kotull
1.0
.1
.1
.7
.4
.*
.t
.1
0.0
Ouollly ol lludy
EXCELLENT
0000
Figure 2
Relationship Between Probability of a Result Being
Adopted and Effort and Quality
Eipoeod 8>Tl>|«
In ToUl Cell On
lo Uotfol Ellorl
Co«t-Uodtl Moro»M«
• nd EPA Adoption EMM
100
» Obuinooio Pnciiiu
© Lotol Ellorl
IXIo"' Rlok ElH«tOill
Flioe1 exrlroMMtil
Eipoooro Lo»1
Figure 3
Relationship Between Costs and Extent of Modeling Studies
posure to multiple PAHs is a potential problem. It was shown
that alterations in the B(a]P dose-response models and the
establishment of B[a]P-equivalent toxicities for other PAH ex-
posures could reduce the theoretical risk by several orders of
magnitude. It will be necessary to exert considerable persuasive
effort, through formal and informal scientific channels, to gain
acceptance of such new approaches by regulatory agencies.
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2. Whittemore, A., "Quantitative theories of carcinogenesis," Ado.
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4. Moolgavkar, S.H. and Venzon. D.J., "Two-event models for car-
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198 RISK ASSESSMENT/DECISION ANALYSIS
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model for human carcinogenesis," J. Natl. Cancer Inst. 66, 1981,
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6. Moolgavkar, S.H., "Carcinogenesis modeling: From molecular biol-
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8. Sims, P. and Grover, P.L., "Epoxides in polycyclic aromatic hydro-
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9. Gelboin, H.W., "Benzo[a]pyrene metabolism, activation, and car-
cinogenesis: Role and regulation of mixed-function oxidases and re-
lated enzymes," Physiol. Rev. 60, 1980, 1107-1166.
10. Weinstein, I.E., Jeffrey, A.M., Leffler, S., Pulkrabek, P., Yama-
saki, H. and Grunberger, D., "Interactions between polycyclic
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Academic Press, New York, NY, 1984, 3-26.
11. Pereira, M.A., Burns, F.J., and Albert, R.E., "Dose response for
benzo[a]pyrene adducts in mouse epidermal DNA," Cancer Res..39,
1979, 2556-2559.
12. Adriaenssens, P.I., White, C.M. and Anderson, M.W., "Dose-
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13. Stowers, S.J. and Anderson, M.W., "Formation and persistence of
benzo[a]pyrene metabolite-DNA adducts," Environ. Health Per-
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14. Lee, P.N. and O'Neil, J.A., "The effect both of time and dose ap-
plied on tumor incidence rate in benzo[a]pyrene skin painting experi-
•ments," Br. J. Cancer 25, 1971, 759-770.
15. Neal, J. and Rigdon, R.H., "Gastric tumors in mice fed benzo[a]py-
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1966, 297-305.
17. Rigdon, R.H. and Neal, J., "Relationship of leukemia to lung and
stomach tumors in mice fed benzo[a]pyrene," Proc. Soc. Exp. Biol.
N.Y., 130, 1969, 146.
18. Anderson, E.L. and The Carcinogen Assessment Group of the U.S.
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Risk Analysis 3, 1983,277-295.
19. Chu, M.M.L. and Chen, C.W., "Evaluation and Estimation of Po-
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Paper presented at the Pacific Rim Risk Conference, 1984.
20. Jeffreys, H., Theory of Probability, 3rd ed., Oxford University
Press, Oxford, England, 1961.
21. Gart, J.J., "Alternative analyses of contingency tables," J.R. Stat.
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22. Laskin, S., Kuschner, M. and Drew, R.T., "Studies in pulmonary
carcinogenesis," In Hanna, M.G., Nettesheim, P. and Gilbert,
J.R., Eds., Inhalation Carcinogenesis: Proc. of the U.S. Atomic
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23. Thyssen, J., Althoff, J., Kimmerle, G. and Mohr, U., "Inhalation
studies with benzo[a]pyrene in Syrian golden hamsters," J. Natl.
Cancer Inst. 66, 1981, 575-577.
24. Finney, D.J., Statistical Method in Biological Assay, 2nd ed.,
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25. Deutsch-Wenzel, R.P., Brune, H., Grimmer, O., Dettbarn, G. and
Misfeld, J., "Experimental studies in rat lungs on the carcinogenicity
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71, 1983, 539-544.
26. Pfeiffer, E.H., "Oncogenic interaction of carcinogenic and non-
carcinogenic polycyclic aromatic hydrocarbons in mice," In: Mohr,
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27. Bingham, D. and Falk, H.L., "The modifying effect of carcinogens
on the threshold response," Arch. Environ. Health 19, 1969, 779-
783.
28. Wynder, E.L. and Hoffman, D., "A study of tobacco carcinogene-
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1959, 1079-1086.
RISK ASSESSMENT/DECISION ANALYSIS 199
-------
The Use of Geographic Information Systems as an
Interdisciplinary Tool in Smelter Site Remediations
Ian H. von Lindern, P.E., Ph.D.
TerraGraphics EEIS
Moscow, Idaho
Margrit C. von Braun, P.E.
University of Idaho
Moscow, Idaho
ABSTRACT
Geographic Information Systems (GIS) represent an emerging
technology that, in recent years, has been applied progressively to
a variety of environmental studies. GIS's ability to flexibly in-
tegrate numerous technical considerations from several disciplines
into a usable format promises to enhance traditional management
and decision-making processes in CERCLA1 projects. In this
paper, two applications of GIS technology to similar toxic waste
sites are presented. The first is a classroom application to a
relatively straightforward soils contamination problem involving
a secondary lead smelter. It provides a classical demonstration of
GIS capabilities in an academically controlled setting. The second
case history is an ongoing CERCLA project involving a huge
primary lead-zinc smelting complex and 21 mJ2 of potentially af-
fected properties, including massive impoundments of mine
wastes, a major river drainage and four cities.
Several lessons can be learned in comparing these case histories.
These include classical problems of "academic versus real world"
applications and the magnitude of difference in technical sophisti-
cation dictated by the relative size and complexity of the sites.
However, equally important lessons concern CERCLA-specific
institutional problems associated with inherent drawbacks in pro-
viding interdisciplinary ends-directed analysis in a litigious expert-
laden environment.
INTRODUCTION
A Geographic Information System (GIS) might be described as
a universal processor of spatial data in map format. However,
GIS is a schizophrenic technology. It suffers an identity crisis and
often is misunderstood in origin, purpose and application. Estes2
has reviewed several systems and found a variety of formats that
differ substantially in capabilities and methods of data storage
and manipulation. Five essential components of a computer-
based GIS are described as: (1) data encoding and input process-
ing, (2) data management, (3) data retrieval, (4) data manipula-
tion and analysis and (5) data display. GIS technology has evolved
from and integrated aspects of several disciplines. University
catalogs list GIS emphasis in Natural Resources Management,
Geography, Environmental Studies, Geology, Cartography,
Landscape Architecture, Remote Sensing, CAD-CAM (Com-
puter Aided Design/Manufacturing) Laboratories, Engineering
and other areas. This extensive list means that GIS has different
meanings depending on the discipline and application. In this pro-
ject, two allied GIS' were utilized. The Map Analysis Package
(MAP)1 distributed for academic use by the Yale School of
Forestry and Environmental Studies and pMAP4, a similar micro-
computer package for professional use. Both are grid-based and
store and manipulate maps in the form of fixed-size cells in Car-
tesian format.
The technology's unique asset in CERCLA application may be
as a technical tool for interdisciplinary endeavors. Superfund pro-
jects offer immense multidisciplinary challenges. Severe technical
problems are encountered in both site assessment and remedial
design. Projects are often the focus of intense public concern and
scrutiny. Community relations, education efforts and political
considerations sometimes become as demanding as the technical
issues. Commonly, major CERCLA projects are litigation-driven
and managed as lawsuits rather than engineering projects.
Congressional mandates and U.S. EPA policies place unmer-
ciful management constraints on site personnel. The certainty
necessary in cleanup and disposal plans, rigid closure specifica-
tions and "bombproof" quality assurance and control (QA/QC)
requirements for litigation leave site managers with few ready
technologies and little flexibility in completing difficult tasks.
Ultimately, this situation has resulted in massive production of
paper products. It is much easier to assess than it is to address tox-
ic waste problems. Reports and site assessments are proliferate. It
is easier yet to critique and review, making reassessments even
more evident. Finally, CERCLA projects are run by committees
of U.S. EPA and state personnel, Potential Responsible Parties
and numerous consultants. These circumstances invite experts to
find basic data insufficiencies, and millions of dollars are spent on
studies, reassessments and studies of studies.
Such problems are common to bureaucracies faced with for-
mulating major technical strategies. Baritz,' in reviewing the
failures of such institutions, noted, "Although efficiency is a
means, not an end, there is an overwhelming likelihood that
bureaucracies will sooner or later, usually sooner, confuse means
and ends, or will simply lose sight of the organization objectives
in the continuous search for higher levels of efficiency." In
CERCLA, means-oriented policies have evolved into an obses-
sion with methodology and assessments to the point of avoiding
ends-oriented cleanup questions. Introducing a new technology,
such as GIS, that cuts across several disciplines in an expert
means-directed climate of "study, critique, but don't act" is a
difficult proposition.
CASE HISTORY I —
DALLAS/RSR SMELTER
This case history was developed for a senior/graduate level
course conducted by the College of Engineering at the University
of Idaho and Washington State University in the spring of 1986
entitled "Computer-Assisted Spatial Analysis of Environmental
Problems."
Background
The RSR facility was a secondary smelter, located in West
200 RISK ASSESSMENT/DECISION ANALYSIS
-------
Dallas, Texas, and was principally involved in recovering lead
from scrap batteries. It operated from the World War II era until
1984. Air pollution from the complex was largely uncontrolled
until primary point source and sanitary emission controls were in-
stalled from 1968 to 1973. Major enforcement actions undertaken
in 1974-75 resulted in additional emissions reduction by 1976.
However, subsequent ambient monitoring showed poor perfor-
mance and best available smelter control capacity was not in-
stalled until 1980.
This long history of uncontrolled and excessive emissions
resulted in gross contamination of local soils by lead particulate.
The smelter was located adjacent to major residential areas. A
400-acre area northwest of the complex contained small single
family dwellings housing approximately 2000 people. Northeast
of the smelter was one of the city's largest public housing projects
including several thousand units within 1 mile of the complex.
Fig. 1 shows a map of land use in the vicinity.
Figure 1
Land Use in Vicinity of RSR Smelter, Dallas, Texas
In 1982 Federal and local government agents cooperated in a
study of childhood blood lead absorption and environmental con-
tamination in the area. Fourteen percent of the preschool children
living within 0.5 miles of the smelter were found to have blood
lead absorption levels in excess of the federal Centers for Disease
Control criterion of 25 /tg/dl whole blood.6 Concurrent analyses
suggested that the excess blood lead levels were associated with
elevated residual soils and current airborne lead contamination in
the neighborhood.7'8 Subsequent court-ordered enforcement ac-
tions required the removal and replacement of contaminated soils
from surrounding residential areas and imposed rigid emission
restrictions on the smelter.9 Civil litigation also resulted in large
recoveries for health and property damage to local citizens. The
complex ceased operations in 1984.
GIS Procedures
Data Base Development
Fig. 2 illustrates the four basic input data "maps" created for
subsequent GIS analyses in this study. These were: (a) Soils Map
plotting the location and concentration of soil lead samples ob-
tained by the EPA, (b) the Landuse/Features Map showing land-
use characteristics, (c) the Housing Map showing the distribution
of dwelling types and (d) the Street Map showing the major streets
in the Study Area. These maps fix the locational aspects of the in-
put data. Other attributes of the same features are retained in a
relational data base. New maps are created by reclassification as
illustrated in the figures and discussion below. Attribute data for
the Landuse/Features Map include zoning categories, principal
use and percent of bare ground surface. Housing attributes in-
clude housing type, unit and per unit population density and
ownership; streets could be reclassified by type, number of lanes,
travel times and traffic volume.
Determining Hazard Zones
The first major classroom analysis was to determine hazard
zones based on projected soil lead levels. Spatial estimation and
contouring of the soils sample grid were accomplished by a variety
of techniques. The course included "nearest neighbor," "weight-
ed distance" (inverse distance squared weighting), "moving-
average" (a method to artificially smooth complex surfaces)10 and
"Kriging" methodologies." These methods all resulted in pat-
terns of contamination similar to those developed by the U.S.
EPA.7'12 Candidate hazard zones were developed by reclassifying
areas within specified isopleths. Several methodologies were
utilized, and zone definitions were based on both mean concen-
tration estimates and the probabilities of exceeding certain limits.
Students designated four categorical zones of contamination or
risk (i.e., severe, moderate, mild and none) as shown in Fig. 3.
SOILS
LANDUSE
HOUSING
STREETS
Figure 2
Four Base Maps Comprising OIS Data Base for Smelter Site
Populations and Properties Affected
After action zones were defined those populations and proper-
ties found within the zone boundaries were assessed. This defini-
tion was accomplished by simple GIS processing that overlaid the
hazard zone map on the desired attribute maps and tabulates
RISK ASSESSMENT/DECISION ANALYSIS 201
-------
Mean Lead Concentration
Estimates (ppm)
Figure 3
Conversion of Isoplethic Estimates to Hazard Zones
values within zone boundaries. Cross-tabulations were developed
for numbers of persons, numbers of dwellings and types of dwell-
ings per hazard zone, number of persons per housing type per
hazard zone, etc. Results of representative analysis are shown in
Table 1.
Table 1
Cross-tabulation of Population and Housing Type by Hazard Zone
Hazard Zone
Severe
Moderate
Mild
Public
Housing
1872
2304
3888
Private
Housing
544
676
1940
Total
2416
2980
5828
8064
3160
11224
Students utilized these results in considering potential remedies.
It was obvious that those areas where major benefits can be
developed do not neatly follow the hazard zone boundaries. In
considering "remedial" zones (in contrast to "hazard" zones),
the real property and population density configurations become
equally important. Remedial zones eventually are defined based
on the intersections of hazard and property and population at-
tribute maps. Moreover, when considering the eventual costing
and design ramifications of remediation, specific geographic units
based on land use attributes are more efficient and defensible
determinants of remedial zones than are contamination estimates.
Several methods of designing remedial zones are available in
the GIS. The simplest involve reclassifying geographic land use or
population units by reversing the overlay procedure above.
Specific geographic areas are designated as remedial zones based
on the distribution of hazard levels within their boundaries.
Reclassification can be based on the mean, median, majority or
maximum hazard encountered or some combination of the
several variables involved. A second, more elegant, method is to
use the moving average surface smoothing algorithm to "mold"
hazard zones around desired land use and population units. The
result of either of these methods is a map of Remediation Zones
indicating areas where some level of corrective action is desired.
Fig. 4 shows example Remedial Zones.
Costing Remedial Scenarios
Cleanup scenarios were then developed for the several remedia-
tion zones. Table 2 shows one such scenario similar to the actual
cleanup accomplished in West Dallas. GIS reclassification and
cross-tabulation procedures were used to develop preliminary cost
estimates for the scenarios. As illustrated in Fig. 5, unit cost
estimates were applied to individual property parcels through
reclassification of the attribute and contamination maps. Various
assumptions were developed regarding disposal requirements for
excavated soils based on projected concentrations, the costs of ex-
cavation and removal associated with access based on the dwelling
type, the cost of health and safety precautions based on concen-
tration and population proximity, excavation volumes based on
housing density and type and costs for street berm and housing
cleanup based on type. The cost results of the Fig. 5 scenario are
202 RISK ASSESSMENT/DECISION ANALYSIS
-------
^^^^^r-
0 900
Zom A -Private Housing
Zone A-Public Housing
Zone B -Print* Housing
ZOM B-Public Housing
Zom C-Commercial Property
Zone D-Smelter Properly
Figure 4
Remedial Zones in Vicinity of the RSR Smelter, Dallas, Texas
shown in Table 3. Numerous scenarios can be accomplished
quickly by simply changing the reclassification assumptions and
repeating the Fig. 5 procedure.
Table 2
Example Remedial Scenario for Figure 4
Remedial Zone
Proposed Remedy
A-Prlvate Housing
A-Publlc Housing
6* soil reapval and replace-water subsidy
6* soil removal and replace - attics cleaned
B-Prlvate Housing Rototlll/Establlsh vegetative cover-water subsidy
B-Public Housing Rototlll/Establlsh vegetative cover
B-Parks/Undev. Rototill/Esubllsh vegetative cover
C-commerclal/
Industrial
Zoning restrictions
Pavement washing
D-Snelter
"Hazardous Waste" Removal
Pave all traffic/storage areas
Emissions Reductions
Modeling Cleanup Schedules
The final course exercise modeled the movement of cleanup
crews and equipment utilizing network transportation analyses
available with the CIS. Truck movement through the community
to disposal areas was analyzed by reclassification of the street
map into time/travel cost maps. Various disposal site locations
and movement constraints on cleanup crews were considered. The
interdisciplinary aspects of a hostile community were interjected
into the last analyses by eliminating certain streets as access and
transportation routes, imposing artifically low speed-limits and
Figure 5
Map Analyses Used to Estimate Costs of Various
Cleanup Scenarios Detailed in Tables 3a-c
Table 3
Typical Remedial Scenario Cosl Cross-tabulations
3a—Soil Remedial Costs by Hazard Zone
Hazard Zone Area (AcI Pickup (»K) Disposal I»K) Total (IK)
Severe
Moderate
Mild
168
202
566
440
484
1198
593
S43
161
1033
1027
1565
o 16
2122
1503
3625
3b—Soil Remedial Costs by Hazard Zone and Landuse Class
Hazard Zone Residential
Soils Cost ($K)
Parlcs/Undev. ccwerclal/Indua. Totals
Severe
Moderate
Mild
699
712
1129
4(1
241
239
74
197
1033
1027
1565
2540
520
565
3625
3c—Soil Remedial Costs by Remedial Zone
Remedial Zone Soil Cost OK)
A-Prlvate
A-Publlc
B-Prlvate
B-Public
B-Park/Undev.
C-Commerclal/Indus.
333
999
820
,;NR
520
565
3625
time-consuming precautionary measures and utilizing alternate
disposal sites to avoid protesters. The cost of these actions in both
time and dollars was evaluated utilizing the G1S procedures.
CASE HISTORY II —
THE BUNKER HILL CERCLA SITE
Background
The 21 m2 area designated for the Bunker Hill Remedial In-
vestigation and Feasibility Study (RI/FS) represents one of the
nation's largest and most complex CERCLA sites. The area is
located in a steep mountain valley drainage in northern Idaho and
has been the center of one of the world's most active and produc-
tive lead, zinc and silver industries for over a century. The current
site boundaries encompass: four incorporated cities; an affected
population of more than 5000 persons; a large river floodplain; an
RISK ASSESSMENT/DECISION ANALYSIS 203
-------
Figure 6
Soils Related Features of Bunker Hill Smeller Sile. Kellogg. Idaho
immense, largely dormant industrial facility including a major
mine and mill works, primary lead smelter, primary zinc smelter,
ammonium phosphate fertilizer plant, over 160 acres of impound-
ed tailings and several hundred acres of contaminated soils and
waste piles. Fig. 6 shows several soils-related features of this site.
A century of mining, milling and smelting has resulted in
widespread contamination of soils throughout the area. Excessive
levels of heavy metals in area soils have resulted from a combina-
tion of waterborne wastes deposited by floods or discharge im-
poundments, deposition of airborne emissions from nearly seven-
ty years of smelter activities and direct dumping of solid waste
materials. Several epidemiological studies conducted over the last
decade have shown excess levels of lead in the blood of area
children. 16'17'lg The most recent studies have concluded that con-
taminated soils are currently the largest contributor to that excess
absorption. Children access the metals in area soils either by
direct contact or through contact with wind-blown dust from bar-
ren areas that contributes to house dust and contaminates
foodstuff.
CIS Procedures
Data Base Development
A comprehensive Data Base Management and Analysis System
has been developed for use in this project. Fig. 7 shows the basic
components of that system. This area has been studied for a varie-
ty of reasons for a long period of time. To maximally exploit the
historical data base, an exhaustive records search was conducted
and an extensive site library was established." More than 2 dozen
state, federal, university and private entities that had conducted
previous studies were visited. More than 100 theses and disserta-
tions, 20 years of regulatory records and several hundred thou-
sand dollars worth of data collected in business, legal, regulatory
and research efforts were reviewed and logged. Standard biblio-
graphic data were entered, and the information was indexed and
cross-referenced by several subject identifiers.
Draft data quality criteria for review and use of historical infor-
mation in the CERCLA process were developed by U.S. EPA
technical and legal staff and contractors. The first of many
CERCLA institutional problems was encountered in applying
these criteria. Of the more than 3,000 items reviewed, only one
met the intitial policy criteria. This nonsensical policy was soon
revised to allow specific use of some data and standards to verify
others. All the available material was reviewed, and two major
historical site characterization documents were developed.'*-15
Selected Data A nalyses
Residential soils in these communities are severely con-
taminated. In a comprehensive 1983 Lead Health Study, 90* of
residences within 1 mile of the smelter were found to have lead
levels in excess of 1000 ppm; 70% of those exceeded 2500 ppm.
(Less than 10"% were greater than 1000 ppm in Dallas in 1982.)
Soils in this survey were extensively sampled in a well-controfleo
effort similar to the Dallas studies. It was thought that application
of the procedures and techniques developed for the Dallas situa-
tion might accelerate the residential soils portion of the Rl/FS.
The basic strategy was to utilize these historical data to develop
preliminary hazard zone estimates to develop a conceptual
methodology to assess population and properties affected and to
204 RISK ASSESSMENT/DECISION ANALYSIS
-------
SITE LIBRARY
RELATIONAL DATA BASE
n
MICROCOMPUTER
OPERATING SYSTEM
MAIN-FRAME
COMPUTER FILE
MANAGEMENT SYSTEM
MAIN-FRAME CIS
MAP
MAIN-FRAME DATA
HANDLING UTILITIES
MAIN-FRAME
STATISTICAL/
ANALYTICAL UTILITIES
-------
where it would be most helpful.
Several discussions, reviews and responses reminiscent of the
classical debate of "how many angels fit on the head of a pin"
followed. It soon became evident that actual sampling would cost
less than fueling the methodological bickering. A wise project of-
ficer obtained a change in U.S. EPA policy allowing advance
sampling of all residential soils. In this case, at least, the applica-
tion of GIS analyses resulted in more rational U.S. EPA policy,
albeit indirectly.
CONCLUSIONS
The variety and sophistication of the analyses accomplished
with a relatively small data base in the Dallas case history demon-
state the flexibility and capability of GIS. Despite its early identity
crisis and less than enthusiastic response from rigid
disciplinarians, GIS promises to do for the analysis of maps,
aerial photography and spatial data, what hand calculators have
done for engineers and field investigators. The level of sophistica-
tion in these endeavors will range from the simplist of "quick-
and-dirty looks" to complex modeling efforts, and some forms of
GIS will perform well across the spectra.
However, in beginning to use GIS as a tool in a real project,
other problems surfaced. The GIS's flexibility and usefulness as a
tool that emulates and assists in logical analyses of diverse data
sources makes it particularly amenable to forms of semi-
quantitative interdisciplinary applications. Such analyses,
however, are vulnerable to esoteric criticism from those
disciplines that are bridged. Such critical review is expected in an
academic or research environment and is, indeed, healthy and
conducive to development of a better technology.
In the CERCLA climate, however, such treatment may be
neither healthy nor wise. Some strict disciplinary experts either
are unaware of, or refuse to recognize, the underlying strategy
and limited nature of the conclusions drawn with GIS or other in-
terdisciplinary analyses. Their critiques, when applied out of con-
text, can be irrelevantly but nevertheless severely damaging to
project credibility in litigation. This is most unfortunate, as many
of the questions that must be resolved in remediation never can
have the level of certainty that technical disciplines impose in
assessment activities. Further, the standard of proof to justify
decision-making in litigation differs substantially from scientific
methodological criteria. The basic steps in both these case
histories, and in CERCLA projects in general, might be described
as: (1) the technical decisions made in investigation and assess-
ment, (2) the decisions involving remedial alternatives and boun-
daries and (3) defending those decisions in cost recovery. The ma-
jor challenges are in the second area where the decision-making
process is forced beyond the security of technical certainty.
In the Dallas classroom example, students were quick to learn
that, however well they fine-tuned hazard zones, the decision as
to "remedial zones" was difficult and involved qualitative and in-
terdisciplinary subjectivity. Similarly, in the actual Dallas
cleanup, a comprehensive analysis of the soils contaminant
distribution was developed by federal personnel. The geostatistics
were to the highest level of precision. However, no federal agency
accepted the responsibility of determining remedial zones. Those
decisions were made in settlement negotiations involving state,
local and private litigant's attorneys with limited technical
assistance.
GIS analyses might have provided a great service in those
negotiations. Classroom students found that the best definition of
remedial zones resulted from evaluating the effects of alternate
scenarios applying different constraints and interdisciplinary con-
siderations. Similar calculations were, doubtless, hand-labored in
the actual settlement. Better, quicker and more sophisticated
"looks" could have been provided with GIS.
206 RISK ASSESSMENT/DECISION ANALYSIS
In the Bunker Hill situation, continual "backsliding" to a
means-directed project is evident. It is clear, with practical cer-
tainty, that residential soils in this area are contaminated 4 to 40
times those levels remediated in Dallas. If the Dallas cleanup
model conceptually applies to Bunker Hill, remediation will be
based largely on land use and population distribution criteria.
Because most of the residential areas in three cities are sorely con-
taminated, cleanup priority will be directed to property parceb
that the population can or wishes to access. Although contami-
nant levels are more severe than in Dallas, interdisciplinary con-
siderations other than pollutant distributions will play a larger
role in determining remedial zones and schedules.
In order to facilitate this cleanup, contaminant levels should be
verified as soon as possible. Basic information regarding current
and projected land use and population characteristics should be
developed and identification of, negotiation with and assimilation
of the decision-making entities into the project should be en-
couraged. Additionally, the interests of these vital participanti
will go far beyond the geostatistical certainty of the contamina-
tion estimates on particular parcels of land. Whether children wi
inhabit the property, property values, taxes, utilities, economic
development potential, zoning and liabilities will be important
considerations to landowner representatives.
Comprehensive efforts should be made to develop answers to
such questions. GIS has great potential to provide such services
through its ability to quickly evaluate numerous scenarios. GIS
well may be a key technical tool in facilitating resolutions to the
many non-technical problems encountered in remedial planning
and negotiations. However, effective use of GIS and other inter-
disciplinary technologies will be difficult in CERCLA projects
unless they are recognized and judged as ends-directed tools.
REFERENCES
1. U.S. Congress. Comprehensive Environmental Response Compensa-
tion and Liability Act of 1980.
2. Estes, J.E., "A Perspective on the Use of Geographic Infonnition
Systems for Environmental Protection," In Proc. of the 2nd Aiuuul
GIS Application Coherence. U.S. EPA EMSL (Laboratory) Us
Vegas, NV, 1986.
3. Tomlin. C.D., "Map Analysis Package," Distributed by the Yak
University School of Forestry and Environmental Studies, New
Haven. CT. 1979.
4. Spatial Information Systems, "The Professional Map Package,"
Distributed by Spatial Information Systems, Omaha, NE, 1985.
5. Baritz, L.. Backfire, Ballentine Books, New York, NY, 1986 ed.
6. U.S. EPA, "Report of the Dallas Area Lead Assessment Study,
Lead Smelters Study Group," Office of Toxics Integration, Wash-
ington, DC, 1983.
7. Brown, K.W., el al., "Assessing Soil Lead Contamination in Dallas,
Texas," J. of Environ. Man. and Assess., 1984.
8. Dallas Alliance Environmental Task Force. "Final Report to the
City Council. City of Dallas, Texas," 1983.
9. State Court - Texas, 95th District. 1983. City of Dallas and Stateof
Texas versus RSR Corporation et al. Docket No. 83-5680-D. Memo-
randum Opinion, Oct. 19, 1983.
10. Davis, J.C. Statistics and Data Analysis in Geology. Kansas Geologi-
cal Survey. Wiley and Sons, New York. NY, 1973.
II. U.S. Geological Survey. "ST ATP AC" - A Statistical Analysis Pro-
gram distributed by the U.S. Geological Survey Service Office, Fed-
eral Service Center, Denver, CO, 1985.
12. Flatman, G.T., Brown, K.W. and Mullins, J.W., "Probabilistic
Spatial Contouring of the Plume Around a Lead Smelter," Pnx-V
the National Conference on Management of Uncontrolled Ha-
ardous Waste Sites. Washington, DC, Nov. 1985, 442-448.
-------
13. U.S. EPA, "The Bunker Hill Site Library System," Prepared for
Region X U.S. EPA, Seattle, WA by Woodward-Clyde Consul-
tants, Walnut Creek, CA and TerraGraphics EEIS, Moscow, ID,
1985.
14. U.S. EPA, "Draft Interim Site Characterization Report for the Bun-
ker Hill Site," Prepared for Region X U.S. EPA, Seattle, WA by
Woodward-Clyde Consultants, Walnut Creek, CA and Terra-
Graphics EEIS, Moscow, ID, 1985.
15. Idaho Department of Health and Welfare, "Draft Geographic In-
formation System and Soils Characterization Report," Bunker
Hill Site RI/FS. Prepared by TerraGraphics EEIS, Moscow, ID,
1986.
16. Yankel, A.J., von Lindern, I.H., et al. "The Silver Valley Lead
Study: The Relationship Between Childhood Lead Levels and En-
vironmental Exposure," JAPCA 27, 1977, 764-767.
17. Walter, S.D., von Lindern, I.H., etal., "Age-Specific Risk Factors
for Lead Absorption in Children," Arch. Env. Health 35, 1980,
53-58.
18. Idaho Department of Health and Welfare, "Kellogg Revisited: The
Results of the 1983 Lead Health Study," Idaho Dept. of Health and
Welfare, Division of Health, Boise, ID, 1985.
19. State Court - Texas 44th District, "Hayes, et al. versus RSR Cor-
poration et al., Docket No. 82-6852-B. Statement of Facts,"
July 2, 1983.
RISK ASSESSMENT/DECISION ANALYSIS 207
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Improving the Implementation of
Remedial Investigation/Feasibility Studies
Using Computerized Expert Systems
J. Steven Paquette
Donald A. Bissex
Royce Buehler
COM Federal Programs Corporation
Annandale, Virginia
Lisa Woodson
U.S. Environmental Protection Agency
Hazardous Site Control Division
Washington, D.C.
ABSTRACT
In this paper, the authors discuss how computerized knowl-
edge-based or "expert" systems have numerous applications
within the RI/FS process. These expert system applications com-
bine traditional data bases with "knowledge bases" characteris-
tic of expert systems. Actual results using the expert system con-
cept on the U.S. EPA's Remedial Program are discussed to
demonstrate how useful expert systems can be to the U.S. EPA
in their remedial program. The development of one operational
system, the Work Assignment/Work Plan Memorandum Gen-
erator, is discussed.
INTRODUCTION
Many of the programs implemented by the U.S. EPA involve
collecting and evaluating technical data and using this data to
develop limits for operating facilities or to promulgate general
regulations. Most decisions made by the U.S. EPA (and their con-
sultants) rely on the composite knowledge of technical experts
and specialists, and many of these are completely amenable to
development by computer aided engineering systems or expert or
knowledge-based systems. In particular, many aspects of the U.S.
EPA's remedial process and the Remedial Investigation/Feasibil-
ity Studies (RI/FS) used by the U.S. EPA to investigate CERCLA
sites have great applicability for the use of these expert systems.
Expert systems are advanced computer programs that simu-
late human expertise to aid a user in the analysis of difficult and
often complex problems. They differ from traditional computer
programs in that they can simulate and integrate a far greater
range of information-representation and information-processing
mechanisms. The systems are developed in sophisticated pro-
gramming languages and "shells" that speed programming and
execution. The technology has evolved over the last several years
to the point where large expert systems now can be implemented
on microcomputer systems.
CDM Federal Programs Corporation (COM) has extensive ex-
perience with the analysis of hazardous waste situations using
computer and expert system techniques. We have worked closely
with U.S. EPA program staff and have demonstrated the utility
of expert systems in the RI/FS process. In our work for the U.S.
EPA, we have shown how the use of this engineering analysis
tool can save months out of a typical RI/FS schedule, stream-
line the administrative requirements of the process and also save
considerable amounts of money.
In this paper, we will present a short overview of the expert
system technology, demonstrate the applicability of these systems
to remedial investigations and describe in detail several technical
applications which we have developed for use on CDM REMII
remedial contract.
THE RI/FS PROCESS
In addition to establishing a fund for financing the cleanup of
uncontrolled hazardous waste sites across the nation, CERCLA
also required that procedures be established to evaluate remedies,
to determine the appropriate extent of the remedy and to ensure
that cost-effective remedial measures are developed which pro-
vide protection of public health and the environment.
One of the means used by the U.S. EPA to evaluate and remed-
iate hazardous waste sites is the Remedial Investigation/Feasi-
bility (RI/FS) Study process. The purpose of this process is to
collect sufficient data to characterize a site so that feasible remed-
ial actions can be evaluated, costed and eventually selected in a
Record of Decision (ROD). The RI/FS process is part of the U.S.
EPA's overall remedial program in which sites are evaluated,
ranked for inclusion on the NCP and remediated through the
Remedial Design and Action process.
The RI 'FS process is an involved technical and administrative
process through which site data are collected, validated and eval-
uated. A normal RI/FS often requires completion of over 40
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The RI/FS Process and Potential Expert System Development
208 RISK ASSESSMENT/DECISION ANALYSIS
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interrelated field and office activities, many of which require EPA
or state involvement. A typical work flow for a normal RI/FS
study is shown in Fig. 1.
RI/FS IMPLEMENTATION ISSUES
A typical RI/FS now takes slightly over 2 years from assign-
ment to completion, i.e., the signing of a Record of Decision for
that particular site. This time frame is months longer than orig-
inally envisioned by the U.S. EPA.
Besides the long duration for these studies there are other issues
that often complicate the implementation of an RI/FS for the
U.S. EPA. These include:
• Lack of experienced senior-level personnel
• Increasing administrative requirements
• Changing program requirements
• Regional and state implementation differences
• PRP negotiations
These issues, and others, can easily be addressed within the
framework of an expert system or computer-aided engineering
system. Rules for completion of parts or all of the RI/FS tasks
can be developed and coded within an expert system. An expert
system essentially captures the knowledge of selected experts
within a narrow knowledge domain. For this reason, the expert
judgment of key program people can be utilized more efficiently
on a larger number of assignments using the expert system tech-
nique.
Administrative and regional variations can be defined within
the expert system rule base, set up once and used routinely with-
out the need to remember or keep track of the many different
RI/FS execution options used by the states and regions.
And finally, new program requirements often alter the RI/FS
decision-making process or modify current technical procedures.
These types of changes can be changed once within the expert
system, and the new program requirement can be implemented
immediately without extensive training or development and trans-
mittal of new guidance material.
The advantages of using expert systems in the U.S. EPA's re-
medial program have been demonstrated with the work CDM
has completed. The many automated systems developed by CDM
have shown that both administrative and technical applications
can be effectively implemented using expert system technology.
Over the past year, we have worked closely with the U.S. EPA
to identify CERCLA expert system applications and are now
actively developing several of the high priority systems. The plan-
ning work we completed with the U.S. EPA led to a classifica-
tion of potential expert system applications. These applications
are also presented in Fig. 1. Additional details on some of these
applications are discussed later in this paper.
EXPERT SYSTEM TECHNOLOGY
Expert systems form part of the broader discipline within com-
puter science known as artificial intelligence (AI). While nearly
every researcher has his or her own definition of this term, we
define AI as the study of how to get computers to make choices
we would regard as intelligent if those choices were made by
human beings.
As AI research evolved, much of the development work
focused on ways to store in the computer the large body of knowl-
edge specific to a particular task, then to approach the task by
combining pieces of this knowledge in relatively straightforward
ways, and finally to keep track of the facts and line of reasoning
employed so that the program could explain how it arrived at its
results in much the same terms that a human expert would. This
new research focus became known as "knowledge based sys-
tems," or "expert systems," and the people engaged in develop-
ing knowledge bases became known as "knowledge engineers."
The tasks which expert systems are built to address ordinarily
will call on knowledge which is ill-defined, largely intuitive and a
matter of exercising judgment rather than adhering to clearly
formulated procedures. If the task had been clearly formalized, a
conventional programming approach most likely would have
been more appropriate. Because the problems expert systems seek
to solve are of this nature, the bulk of the work that goes into
their construction goes into understanding how the expert thinks.
Thorough understanding of how the expert thinks will not come
all at once, but is an important component of the knowledge engi-
neering process so that the resulting system correctly models the
expert's thought processes for an accepted percentage of applica-
tions.
An expert system contains two kinds of knowledge which are
kept strictly segregated in the interests of efficiency. First, it has
knowledge about logical inference and general problem solving
methods; the part of the system that embodies this general knowl-
edge is referred to as the "inference engine." The creators of an
expert system usually will purchase most or all of the inference
engine off the shelf so that they can concentrate on the second
part of the system, where detailed knowledge about the problem
domain is stored. This second part of the system is known as the
"knowledge base."
The concept of a knowledge base is not to be confused with the
familiar notion of a data base. A typical data base consists of raw
data, of columns of numbers and names much like those in a
financial spreadsheet. A knowledge base stores information at a
higher, more conceptual level in the form of facts and rules; this
information is not constrained to fit into any predefined matrix
of rows and columns. In a system to draw up an employee health
and safety plan for a CERCLA RI/FS, for example, the knowl-
edge base would encompass facts and rules like the following:
• DATA: (1) The measured atmospheric concentration of
toluene at the site is 734 mg/m3.
(2) Neoprene clothing will survive at least 1 hour of
exposure to aliphatic hydrocarbons.
• RULE: If a substance can be classified as a combustible gas
and the substance is present at the site and the oxygen con-
centration meter in a zone shows at least 19.5% oxygen and the
combustible gas indicator in the zone reads 10% to 20% of
LEL and an activity will involve work in that zone, then assign
an additional person to that activity to monitor the combus-
tible gas indicator.
Rules like the one just quoted, known as "if-then rules" or
"production rules," are the most common form used for expert
system rules. Another common type is the inheritance rule. For
example, an inference engine that understood the operation of in-
heritance rules would take "An FID is a kind of monitoring de-
vice" to mean "All rules that apply to monitoring devices apply
to FIDs." Special logical mechanisms like this allow many rules
to be condensed to a few and improve the clarity and efficiency
of the system.
The expert system's ability to deal with information at the level
of knowledge rather than at the level of data has two beneficial
side effects. In traditional computer systems, the programmer
also might begin with a set of facts and rules, but he would have
to translate them to the level of operations on simple data before
the computer could understand them. Using expert system tools,
he does not need to go through that translation. For those sys-
tems that are susceptible to the expert systems approach, this ap-
proach results in greatly reduced programming costs. Second, be-
cause the information is still in fact/rule form while the com-
RISK ASSESSMENT/DECISION ANALYSIS 209
-------
puter js working on it, the computer can explain what it is doing
at each step in immediately comprehensible terms. It can quote
the facts, rules and line of reasoning used to reach any of its con-
clusions or recommendations.
EXPERT SYSTEM DEVELOPMENT PROCESS
More formally, we can identify six steps in the knowledge en-
gineering process (Fig. 2). First, the problem is defined. This iden-
tification process involves locating sources of information: ex-
perts, textbooks, reference manuals and guidance documents;
steeping oneself in these materials to get a broad understanding
of the field; and setting clear, realistic boundaries on the task the
system is to perform. The scope of the task must be neither so
narrow that a successfully built system will not be of significant
practical value, nor so broad that the system cannot be built with
currently available tools and within the resources committed to it.
Second, the problem is conceptualized. The knowledgeable engi-
neer determines the principal objects the expert thinks about, de-
termines their important characteristics and asks the fundamental
questions the expert would ask as he begins work on a problem.
Third, the problem is formalized. A particular computer model
is laid out for the concepts extracted in the second stage. Then
the process enters the main cycle of knowledge engineering, in-
corporating several iterated steps: (1) interview the expert and
extract new information; (2) express that information in the form
of rules and enter the rules into the knowledge base; (3) test the
revised system (the experts may be present at the more formal
tests); and (4) conduct the next interview on the basis of the test
results.
Figure 2
Expert System Development Process
Expert systems have been successfully developed to deal with a
wide variety of serious real world problems. They have been
used, for example, to diagnose and prescribe for bacterial infec-
tions (MYCIN), configure minicomputer installations (XCON),
reduce the structure of complex organic molecules (DENDRAL)|
and review geological data to recommend places to drill for ofl
(PROSPECTOR). As we will indicate, many of the component
tasks of planning and administering a CERCLA Rl/FS satisfy all
our criteria.
CURRENT COMPUTER-BASED APPLICATIONS
Since the onset of the REM II contract, CDM has aggressively
researched the role of automated systems in the CERCLA re-
medial process in order to make more efficient and effective use
of available resources. These automated systems include both
traditional applications for database and financial modeling as
well as more advanced applications such as knowledge-based ex-
pert systems. The philosophy of systems development has been
a modular approach so that the many parts may be used individ-
ually or together for building larger, integrated systems.
CONVENTIONAL SYSTEMS
The conventional micro- and minicomputer systems now in use
include those for office automation, cost accounting and esti-
mating, and various technical database systems. Two of the main
database systems are REMTECH, the technical database, and the
Chemical Compound database.
REMTECH is a relational database system developed to main-
tain large amounts of technical data from hazardous waste sites.
The system resides on a VAX-11/785 minicomputer. Included
are facilities to enter, edit and retrieve data related to on-site
sampling and laboratory testing of samples. A microcomputer
data entry system permits users to enter data locally on micro-
computers to be verified and uploaded into the VAX database
system. The file generation feature allows users to select data for
numerous report formats or ASCII fiat file generation. These
flat files may be input to other VAX-based systems or may be
downloaded to microcomputers for input to micro-based com-
puter programs. These other types of programs include systems
for graphics, statistics, reports and expert systems requiring tbese
sampling data.
The Chemical Compound database system contains over 70
chemical, physical and biological properties for hundreds of com-
pounds. Included is information relating to health hazards, flam-
mability and reactivity characteristics, environmental properties
and personnel protection and monitoring characteristics.
EXPERT SYSTEMS
The development of expert systems at CDM grew out of a need
for increasingly more powerful, robust systems to aid the remed-
ial planning activities of the REM II contract. The early expert
system development was CDM sponsored research in order to de-
termine the applicability of expert systems in the remedial pro-
cess. These initial efforts proved fruitful, leading to further devel-
opment of in-house systems and a U.S. EPA Work Assignment
for expert system development.
One such system is the Health and Safety expert system which
is being used to generate concise, practical health and safety plans
(HSP). The purpose of the HSP is to establish site-specific re-
quirements for protecting the health and safety of personnel dur-
ing all activities conducted at a site. The primary data required
as input to the system includes site-specific information such as
location, site size and type, a description of the tasks to be com-
pleted and known contaminants and their quantities. The output
210 RISK ASSESSMENT/DECISION ANALYSIS
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of the system includes contaminants of concern including health
effects, required personal protection apparel, equipment required
and recommended monitoring procedures. Many of these data,
such as the chemical data, reside in conventional databases
accessed by the expert system.
A current U.S. EPA Work Assignment for expert system
development addresses the need of the U.S. EPA to estimate
schedules and financial requirements for all of its remedial assign-
ments. The purpose of this assignment is to investigate systems or
procedures that could be used to provide the agency with more
accurate schedule and financial estimates to: (1) aid in planning
funding and scheduling requirements for the remedial program
and (2) better forecast phasing of assignments and future resource
requirements for both contractor and agency personnel.
Another expert system is the Work Assignment/Work Plan
Memo (WA/WPM) generator which automates one of the more
routine, but time-consuming steps in the startup of site investiga-
tion activities. The output of the WA/WPM system is a draft
word processing document including a cover sheet with admin-
istrative information, descriptions of core and optional tasks re-
quired and a level-of-effort matrix of each task divided into four
job categories, ODCs and travel and expense categories. The sys-
tem also will optionally generate a Work Plan Memo consisting
of a cover letter and confidentiality letters to be signed by key
Work Assignment personnel. The system requires three types of
data to be input including administrative information, data from
the Hazard Ranking System worksheets and a series of site-spe-
cific questions.
A CLOSER LOOK: WORK ASSIGNMENT/
WORK PLAN MEMO EXPERT SYSTEM
The Work Assignment/Work Plan Memo (WA/WPM) gen-
erator creates two documents which are required to begin work
on a hazardous waste site. These documents are the Work Assign-
ment which is issued by the U.S. EPA and begins the process by
notifying CDM to initiate the remedial planning process. CDM
accepts the Work Assignment by signing and returning this docu-
ment and begins drafting the Work Plan Memo. The Work Plan
Memo outlines in general terms each task that will be completed
during the Remedial Investigation and Feasibility Study and in-
cludes the level of effort required for each task for each of four
job groups, ODCs and travel and expense estimates. Knowledge
of the remedial planning process, regional and state requirements,
contractor labor rates and site-specific characteristics must be
known to draft the Work Plan Memo. The current manual sys-
tem of drafting a Work Assignment and Work Plan Memo takes
3 weeks to 3 months and an average of 150 man-hours. The WA/
WPM expert system reduced this to 2 to 3 days and an average of
16 man-hours.
The Work Assignment/Work Plan Memo expert system re-
duces the time required to generate and approve the Work Plan
Memo in order to begin work on a hazardous waste site. The time
required for the process is reduced for several reasons. Since the
expert system was developed to CDM and U.S. EPA specifica-
tions on writing Work Plan Memos, the expert system may be
operated by U.S. EPA personnel with the output in a sense "pre-
approved" by CDM. Of course both parties must review the doc-
uments before signing, however pre-approval of the knowledge-
base by both parties greatly reduces the amount of editing re-
quired. In addition, data are entered into the system in three
parts; the first two data bases can be entered by support staff
while the last data set contains technical questions requiring
knowledge of the specific hazardous waste site. All three sections
can be completed by support staff if data entry forms are filled
out in advance by those people knowledgeable about the site.
This system allows the technical staff to work on more unique or
challenging problems.
Time savings also are realized due to the fact that the finished,
edited documents reside on the CDM computer and are trans-
portable to other word processing systems fully compatible with
the CDM system. This allows documents to be transferred be-
tween machines and sent to other users electronically, with the
traditional paper mail system reserved for final versions requir-
ing signatures.
Where a selected task or the hours required appear to be in-
appropriate, we can determine why and update the knowledge
base by changing or adding a rule or modifying the standard
hours required. This flexibility is particularly important for a sys-
tem which is dependent on changes in regulations or laws. These
changes become implemented immediately for all users of the sys-
tem. In this manner, the expert system learns incrementally much
like a human expert does. The difference is that the system is
storing the knowledge of many experts and, unlike a group of ex-
perts, the system must learn a new rule only once; each expert
must learn a rule for himself.
The development cycle of the WA/WPM was approximately 6
months from the time the problem was defined to the develop-
ment and testing of the research prototype. However, there is no
one approach to developing an expert system. The steps in the
development of the Work Plan Memo Generator described be-
low did not simply follow one another; there was a constant re-
evaluation of each component as the project progressed:
• Selection of an appropriate problem is the most critical step in
ensuring the success of a project—The WA/WPM project was
seen as a simple application with a high payoff in terms of time
savings at the beginning of the remedial process.
• Problem familiarization and scheduling—This step included
general research to obtain a basic understanding of the prob-
lem domain. The goal here was not to become an expert in the
problem domain, because doing so may bias the outcome of the
knowledge engineering sessions. Project scheduling with a clear
understanding of time, budget and personnel constraints will
assist in project success.
• Identify the experts in the problem domain to include them in
the knowledge engineering sessions—The goal was to have just
enough information to stimulate discussion and look at the
problem from different perspectives without being over-
whelmed with different points of view. If the problem were
properly defined, the heuristics or "rules of thumb" gleaned
from the experts should not greatly differ from expert to ex-
pert. There were six such experts identified for the WA/WPM
project. Since these individuals are expert in their fields, the
demand on their time was great and therefore often difficult to
schedule. Top management support played a critical role in ob-
taining their time.
• Problem scope determined but remained flexible—The devel-
opment team occasionally evaluated the problem for appro-
priateness and potential for success. We were prepared to mod-
ify the scope to ensure success in a reasonable amount of time.
• Knowledge engineering sessions—There is no optimal num-
ber or length of engineering sessions. Three sessions were held
for the WA/WPM project, each lasting 1 day. Numerous less
formal discussions with the experts clarified points of confus-
ion and continue as the knowledge base is constantly evaluated.
• Formalize the problem—The basic concepts and their relations
were represented within the language framework.
• Develop rules—The IF...THEN rules are developed to proper-
ly model the knowledge of the experts. The object was to create
enough rules to create the prototype system which will be used
in further development and refinements. The rules were coded
RISK ASSESSMENT/DECISION ANALYSIS 211
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into the program environment; in this case, the programming
system used was OPS-5.
• Prototype system created—A prototype system was developed
within 1 month of the first knowledge engineering session. A
prototype is usually only useful for a limited number of cases
presented to it. Many of the user-interface questions were
addressed in developing the prototype. A working prototype is
important in justifying continued development.
• Testing—Initial testing proceeded in conjunction with the cod-
ing of rules as the knowledge base grew and became more com-
plete. The system evolved through several levels of "proto-
type" systems until the system gained depth and breadth at
solving problems. The testing involved the experts, end-users
(including technical and non-technical personnel) and man-
agement.
• Delivery to the end-user—This step must address any final end-
user issues to ensure the system will be accepted with minimal
coercion. Good, concise documentation with worksheets, sam-
ples, facts and rules contained in the system all assist the user in
understanding and thus finding the system a useful productivity
tool.
CONCLUSION
The advantages of using expert systems in the remedial plan-
ning process have been demonstrated with the applications CDM
has developed to date. By streamlining many of the tasks using
expert system technology where it is most applicable, the experts
can concentrate on the more complex, unique cases or problem
areas. The use of expert systems based on multiple sources of
knowledge can lead to a higher level of consistency and accuracy
and more informed decision-making in less time or when the ex-
perts are not available. Additional benefits of expert system tech-
nology include using them as training tools for new or less tech-
nical personnel and using them for hypothesis testing to better
understand the problem domain.
212 RISK ASSESSMENT/DECISION ANALYSIS
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Coping with Data Problems While Performing
Risk Assessments at Superfund Sites
David H. Homer, Ph.D
John A. Dirgo
Harry V- Ellis III, Ph.D
Eric S. Morton
P.R.C. Engineering, Inc.
Chicago, Illinois
ABSTRACT
The U.S. EPA requires that a risk assessment (sometimes called
an endangerment assessment, public health assessment or environ-
mental assessment) be performed at each Superfund site. The
assessments may be part of a remedial investigation/feasibility
study or part of an enforcement action. The purpose of these
assessments is to evaluate all relevant site-related data and deter-
mine the potential risk to human health and the environment from
site releases. PRC has performed risk assessments for the U.S. EPA
at several Superfund sites throughout the country.
This paper describes some of the problems encountered in
preparing assessments, focusing on those problems associated with
site and supporting data. Specific problems include evaluating site
data for quantity or quality, addressing variability in available data,
identifying major site contaminants, obtaining media-specific data
on contaminant fate and transport and contaminant toxicology,
obtaining information or concentrations and determining which
procedures to use to characterize risk from site releases. The paper
describes how these problems were addressed and solved.
INTRODUCTION
A risk assessment is a tool used to estimate the probability of
harm to a receptor from exposure to toxic agents. The U.S. EPA
has recognized the importance of risk assessment and risk manage-
ment in environmental regulatory decisions '. The agency has
published in the Federal Register a series of proposed guidelines
to be used in assessing various types of risks, such as carcinogenic,
mutagenic, developmental and systemic risks and risks from
chemical mixtures 2-3'4-5.6.
In CERCLA, Congress requires that the U.S. EPA assess risks
at hazardous waste sites. Specifically, Section 106(a) of CERCLA
states that ".. .when the President determines that there may be
an imminent and substantial endangerment to public health or
welfare or the environment because of an actual or threatened
release of a hazardous substance from a facility, he may... secure
such relief as may be necessary to abate such danger and threat."
The risk assessment* aids in determining whether a release from
a site poses an imminent and substantial endangerment. The risk
assessment evaluates the actual or potential releases from the site
and estimates the impact of those releases. The U.S. EPA then
uses the assessment results, along with other information, to decide
whether relief is required at the site. Risk assessments also are used
to evaluate any remedial action proposed for a site; specifically,
whether remedial actions will mitigate any of the risks posed by
site releases.
PRC has performed risk assessments at numerous hazardous
waste sites throughout the country to fulfill the U.S. EPA's man-
date under CERCLA. Each site was unique and had its own set
of problems; however, certain types of problems occurred at many
of the sites. This paper presents several of the general and site-
specific problems encountered and discusses how these situations
were addressed.
THE RISK ASSESSMENT PROCESS-
PROBLEMS AND SOLUTIONS
The risk assessment process includes seven major steps:
Reviewing existing data
Identifying major contaminants
Determining contaminant fate and transport
Identifying exposed populations
Estimating exposure doses or concentrations
Reviewing contaminant toxicity
Characterizing the risk associated with exposure
These steps, along with problems that have been encountered
and the methods used to solve those problems, are discussed in
the following sections.
Reviewing Existing Data
The most important input to any risk assessment is the data used
to characterize site releases. Therefore, it is necessary to obtain
as much data as possible relating to contaminant releases from a
site. The data available for a specific site can pose problems in
terms of quantity, quality and variability.
The quantity of available data may pose the first problem. In
conducting risk assessments, there have been instances when the
only data available were one set of data from one sampling effort.
In some cases these data did not identify the extent of the con-
tamination of the site but only determined whether contamination
was present. Also, since the set of data was for one sampling effort
only, the assessment team could not determine whether the con-
taminant concentrations were increasing, decreasing or remaining
constant and whether they varied seasonally. In instances such as
these, the data cannot be manipulated; however, if the data are
of good quality they may be of value. To use such data in a risk
assessment one must be aware of their limitations.
Where very large amounts of data exist, the data can be screened
to eliminate duplicate or incomplete information. The most useful
data are those which are from consistent sampling locations over
a long period of time. Computerized databases greatly assist in
manipulating large numbers of data points. At one site, over 16
years of daily or weekly data existed for one contaminant of
concern at two key locations. After entering all these data into a
database, we could readily calculate monthly and annual averages
and draw graphs of variations within years and between years.
From this analysis, we could easily evaluate the data and predict
the degree of contamination.
Major problems that influence the quality of the data are
encountered routinely, especially at a site that has been studied
for a long period of time. Various groups may have sampled the
site with no specific long-term objectives. In this situation, samples
often were taken just to "see what was there." To evaluate such
data, as much information as possible should be obtained regarding
sampling, sample handling and analytical procedures. At a site in
Indiana, large differences existed in analytical results for heavy
RISK ASSESSMENT/DECISION ANALYSIS 213
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metals from groundwater monitoring samples taken by two dif-
ferent groups. By obtaining information on sampling procedures,
the assessment team eventually determined that one group did not
filter or preserve their samples in the field, but did filter and
preserve the samples in the laboratory. As a result, the heavy metals
precipitated out of solution and were removed before analysis.
Since heavy metals were the contaminants of concern at this site,
the data generated by this group did not accurately represent site
conditions and could not be used.
The analytical techniques used also present problems when
various groups study a site. This is especially true if the data are
from several different laboratories. It is important to determine
the analytical techniques used and the quality assurance/quality
control (QA/QC) procedures used. However, this can be difficult.
PRC evaluated a site in California with over 40 years of analytical
data available. No QA/QC information was available on the earlier
data; however, there were several ways to evaluate the data. First
the earlier data from the background areas were compared to the
present day background data obtained with acceptable QA/QC
procedures, and they were found to be similar. Information was
available on the procedures used to analyze the samples. An
evaluation of the analytical procedures did not indicate any of the
major constituents found at this site that may have influenced the
results. Based on these evaluations, it was decided to use these data
in the site evaluation.
If QA/QC procedures cannot be verified, then the data may only
be of limited value. In addition, when sample analyses are not con-
ducted by a reliable source such as a federal or state laboratory
or an industrial laboratory with a long record of excellence, the
risk assessment based on these data may be limited to a qualitative
assessment only.
Variability in data also may present problems. This variability
especially occurs with groundwater monitoring results from land-
fills. Several procedures may be used to evaluate analytical results.
First, it is usually helpful to evaluate the contamination levels in
a specific well over time and determine whether there is a trend
of increasing or decreasing contamination. Statistical tests, such
as regression or time series analysis, may be applied to these data;
however, PRC has found that, in most situations, available data
are insufficient for detailed statistical analysis. Another helpful
technique is to determine contaminant concentration isopleths that
aid in visually presenting the data. A series of contaminant isopleth
figures may be used to show if contamination concentrations have
changed over time. They also may be used to show the extent of
contamination and the direction of contaminant migration.
When groundwater monitoring data are evaluated, it is impor-
tant to know whether the wells monitored the same aquifer at the
same approximate depth. At a site in New Jersey, groundwater
wells monitored three distinct geologic units. The approach used
in this case was to group results from each geologic unit and com-
pare the upgradient results to the downgradient results within each
unit to determine whether a significant increase had occurred. The
sample results of each unit were compared to determine whether
contaminants found at the site had migrated to the lower units.
Identifying Major Contaminants
The number of contaminants identified at a Superfund site can
vary widely—a site in New Jersey had over 100 contaminants, while
a site in Delaware had less than 30. However, in both situations
it was not feasible to evaluate the potential risk from exposure to
all the contaminants. The question is how to identify the major
contaminants at the site.
The Superfund Health Assessment Manual 7 contains pro-
cedures to identify the major contaminants (indicator chemicals)
at a site. This procedure uses a formula to obtain an indicator score
for each contaminant. The formula is determined by multiplying
the contaminant concentration by the toxicily constant for that
contaminant (the constant is media-specific and is given in the
manual). PRC's assessment team calculates these scores for
maximum and mean concentrations found at the site. The team
does not, however, use these scores alone to identify the major
contaminants. After the scores are obtained, a group is assembled
to review the indicator scores. The group may consist of achemist,
lexicologist, environmental scientist, public health scientist]
geologist and hydrologist. This group reviews the indicator scores
for the site contaminants and other site data. The group looks
specifically at site data to determine if outlying data points may
have unrealistically influenced the scores. It also evaluates the
changes in a contaminant's concentrations over time and whether
the contaminant has been identified in many samples or only in
occasional samples. It also is important to compare a contaminant's
score in each medium, looking for those contaminants that scored
high in all media.
The fate and transport characteristics of the contaminants also
are considered, specifically, whether they will migrate or persist
in the media at the site. Contaminants of similar structure are
grouped together, with the objective of using one of the compounds
to represent the entire class of compounds. For example,
trichloroethene may be used to represent other chlorinated ethenes.
The group also will review the site history to determine whether
the contaminants identified actually originated from the site. Take,
for instance, a site in Ohio located adjacent to a strip mine. During
the risk assessment, the PRC assessment team had to consider the
influence of acid drainage from the mine when identifying the
major contaminants from the site.
The team identifies the final list of major contaminants based
on the above evaluations. No strict protocol is used; instead, we
rely on the experience and professional judgment of team members.
The total number of major contaminants identified usually varies
between 5 and 10.
Determining Contaminant Fate and Transport
Once the pertinent-to-site contamination data have been
evaluated and the major site contaminants have been identified,
the next step is to review the available data on the environmental
fate and transport properties of the major contaminants. One of
the major problems encountered is that specific site information
describing a contaminant's behavior relative to actual conditions
rarely is available. In these cases, one must rely on literature
information concerning the behavior of a specific constituent in
a generic context. For many chemicals, only limited information
is available concerning their behavior in the environment. It is then
up to the professional to interpret this information and predict the
behavior of a contaminant at the site.
Often information is available which describes the behavior of
a structurally related chemical in conditions similar to those at the
site. For example, at one site a contaminant of concern was
1,1 -dichloroethene; the major transport medium was groundwater.
Although hydrolysis is a process that may impact the fate of
1,1 -dichloroethene, no information specific to 1,1 -dichloroethene
was found on this process. Instead, information was reviewed on
the hydrolysis of two other chlorinated ethenes compounds—
trichloroethene and letrachloroethenc. Because of the similar struc-
tures of the three, PRC inferred that 1,1-dichloroethene may behave
in a fashion similar to trichloroethene and tetrachloroethene and
have a comparable half-life in water. The same type of procedure
has been used for other processes such as photolysis, oxidation,
volatilization, sorption, bioaccumulation, biolransformationand
biodegradation.
Some of the properties that influence a contaminant's fate and
transport can be estimated. Handbooks, such as Lyman and Reehl
and Rosenblatt8, which contain procedures to estimate such pro-
perties as octanol/water partition coefficient, solubility, bioconcen-
tration factors, rate of hydrolysis, rate of biodegradation, volatifio-
tion from water or soil and atmospheric residence time, are
available. For an assessment of a New Jersey site, PRC estimated
the bioaccumulation of PCBs in aquatic organisms based on water
concentration. This information then was used to estimate potential
exposure to populations consuming these aquatic organisms.
Identifying Exposed Populations
To assess the risk from a site release, one must identify the human
and environmental populations that may be exposed to such a
release. One process which consists of several steps has been used
214 RISK ASSESSMENT/DECISION ANALYSIS
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to successfully identify those populations. The first step is to
develop exposure scenarios. The exposure scenarios identify the
mechanisms of exposure (such as ingestion of groundwater or
inhalation of dusts) and identify specific populations exposed (such
as those using groundwater as a drinking water source or children
playing in contaminated soils). The scenarios rely on information
regarding the contaminant's extent, fate and transport properties
and area populations. The exposure scenarios should be developed
around the major contaminant migration pathways and sources,
such as groundwater, surface water, soils, sediment and air. Since
these scenarios should be as realistic as possible, site visits are
extremely helpful. If the assessment team does not visit the site,
unrealistic scenarios may be developed and others may be com-
pletely overlooked.
Once the scenarios are developed, the next step is to describe
the populations that may be exposed. In many instances, problems
arise in attempting to quantify these populations. Information on
human populations can be obtained from census surveys. In
addition, local public health agencies may be excellent sources of
information. At an Indiana site, the assessment team was concerned
whether homes downgradient from a leaking surface impoundment
used groundwater as a drinking water source. To address this con-
cern, the team first checked local registers of groundwater wells.
However, due to the imprecise nature of those records and the age
of some of the potentially impacted homes, it was possible that
the register information was not current. Next, the local water
utility was contacted. They compared the addresses of the poten-
tially impacted homes to their list of customers. The list of homes
obtained from the water utility was then cross-checked with a city
directory to verify addresses. Those homes not identified as being
serviced by the utility were visited to confirm their use of
groundwater.
Problems occur when attempting to describe exposed environ-
mental populations. At most Superfund sites, there has been no
sampling to quantify either the aquatic or terrestrial populations.
At several sites, the only data available on local populations have
been obtained from studies where the objective was to determine
whether tissues of organisms found near the site contained signifi-
cant concentrations of contaminants. These data can be used
qualitatively to characterize local populations.
Another way to obtain information about environmental popula-
tions is to contact state and federal agencies, such as the Depart-
ments of Fish and Wildlife, Conservation or Natural Resources,
to obtain any biological survey information on the general site area.
If the information is not available, these agencies may have publica-
tions which describe the major regional or state habitats and the
species common to those habitats. In addition, general literature
may contain this type of information.
Estimating Exposure Doses or Concentrations
Once exposed populations have been identified, the next step
is to estimate the exposure doses (or concentration) and the
exposure frequencies. Estimation of exposure doses may be the
most straightforward aspect of the exposure assessment; it also can
be the most difficult. For example, at a site in Connecticut,
analytical results from residential wells adjacent to the site were
used to determine exposure from ingestion of contaminated
groundwater. If aquatic organisms are the exposed population,
surface water concentrations have been used to determine the extent
of exposure.
In other cases, a mathematical model can be used to predict the
concentration. Using such a model, however, is the exception rather
than the rule. Most models, such as groundwater flow models or
air dispersion models, require a minimum amount of data before
they can be used. A groundwater flow model may require infor-
mation on flow direction and velocity, porosity and permeability
of the bedrock and pump test data. An air dispersion model used
to estimate releases from a surface impoundment may require in-
formation on the contaminants' physical/chemical parameters such
as vapor pressure, Henry's law constant, solubility, liquid phase
mass transfer coefficient and gas phase and liquid phase exchange
coefficient. Also required would be data on wind speed,
temperature, surface area and depth of the surface impoundment
and flow velocity. In most instances, there is insufficient infor-
mation available to support even a simple model; this is especially
true with groundwater contaminants.
Air releases from surface impoundments are more likely can-
didates for modeling because the data required usually are available
or can be estimated. PRC has modeled releases from surface
impoundments in Texas and New Jersey using a combination of
several models9'10'". The approach used to estimate releases was
to treat the surface impoundment as a point source and determine
the emission rate of contaminants to the atmosphere9'10 This
emission rate was then applied to another model to calculate pollu-
tant concentrations downwind of the source11.
Another problem encountered is the contaminant concentrations
to use in estimating exposure doses for each medium. PRC has
used both maximum and average contaminant concentrations
found at the site to establish the "worst case conditions" and
"realistic case conditions." The worst case conditions is based on
the highest concentrations found at the site in the medium of
concern, while the realistic case condition is based on mean con-
centrations. By developing both exposure estimates, a better under-
standing is gained of the spectrum of possible exposures.
The average and maximum contaminant concentrations at the
site usually are determined during the review of existing site data
and are used to identify the major contaminants. Usually the data
from each sampling point are entered into a personal computer
using a spread sheet format. These data are manipulated to deter-
mine the maximum and mean concentrations for each contami-
nant identified and in each medium of concern at the site. To aid
in evaluating these data, it is helpful to indicate the frequency of
detection for each contaminant. This frequency of occurrence gives
the risk manager a better understanding of the site data and how
to weigh the "worst case" versus "realistic case" conditions.
Reviewing Contaminant Toxicity
The previous steps in the risk assessment process identified the
site's major contaminants, their fate and transport properties,
exposure scenarios and estimates of exposure doses or concentra-
tions. The next step is to review available data on the toxicity of
the major contaminants, focusing on the exposure routes expected
at the site. As was the case with the fate and transport informa-
tion, site-specific information on the toxicity of a contaminant,
such as epidemiology studies, usually is not available. The accepted
practice is to use data from toxicity studies that have similar ex-
posure routes—ingestion, inhalation or direct contact. In cases
where information is not available for a specific exposure route
(such as toxicity via ingestion), it may be possible to use information
for other routes (such as'toxicity via inhalation). However, an
understanding of the behavior of the chemical in a biological system
is required to draw conclusions from one exposure route and apply
them to another. In making these inter-route comparisons, con-
cern about absorption and metabolism are foremost.
Characterizing Risk
The last step in the risk assessment is to assemble all the data
to characterize the risk associated with releases from the site. One
of the major problems with this step is deciding whether the risk
characterization should be quantitative or qualitative. The ability
to perform quantitative analysis depends on the quality and quan-
tity of the available data and whether any required assumptions
are reasonable. No hard and fast rule has been developed to resolve
this issue; professional judgment must be applied. For example,
one may not want to calculate a carcinogenic risk estimate based
on one set of data taken at a site 3 years ago, as occurred with
a site in Texas. Rather than perform such a calculation, it may
be appropriate to qualitatively assess the risk by comparing the
data to U.S. EPA standards, criteria or guidelines, such as maxi-
mum concentration limits in the Safe Drinking Water Act, ambient
water quality criteria or Health Advisories (formerly known as
Suggested No Adverse Response Levels—SNARLS). On the other
hand, if quality data are available in sufficient quantity, then the
RISK ASSESSMENT/DECISION ANALYSIS 215
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risk can be characterized quantitatively, as was the case for a site
in Florida. Several years of data were available for this site from
monitoring wells located in an area that contained several drink-
ing water wells. These data were used to calculate an estimate of
the carcinogenic risk for the area represented by the monitoring
wells.
The grey area occurs when the data are insufficient to predict
concentrations at the point of greatest potential exposure, but are
available for an area where exposure is limited or may occur in
the future. In many instances, PRC has chosen to assume that
exposure will occur in the future and estimate the potential risk
to future populations.
Evaluation of risk to aquatic communities usually is limited to
a qualitative assessment. A common practice is to compare surface
water concentrations to the U.S. EPA's ambient water quality
criteria. At present, we have not attempted to determine the impact
of contaminants on the entire ecosystem because limited amounts
of biological, chemical and physical data are available on the
specific ecosystem impacted by releases from a site.
CONCLUSION
In summary, risk assessment is a tool used to estimate the prob-
ability of harm to a receptor from exposure to toxic agents.
CERCLA mandates that the U.S. EPA perform a risk assessment
at each Superfund site. The agency uses these assessments and other
information to effectively manage the risks posed by a Superfund
site.
PRC has performed risk assessments at numerous hazardous
waste sites throughout the country to support U.S. EPA. Although
each site was unique and had its own set of problems, certain types
of problems occurred at many of the sites. These problems
included: evaluating data for quantity, quality and variability;
identifying major contaminants; obtaining data on contaminant
fate and transport properties; determining toxicological properties;
identifying exposed populations; estimating exposure; and
characterizing risk.
This paper has presented various methods that have been used
to solve some of these problems. In most instances, research beyond
the initial set of information was required. Professional expertise
and judgment also played a role in solving these problems. The
procedures presented may be only some of the ways to solve these
problems.
REFERENCES
1. U.S. EPA, "Risk Assessment and Management, Framework for
Decision-Making," EPA 600/9-85-002, Dec. 1984.
2. U.S. EPA, Office of Health and Environmental Assessment "Pro-
posed guidelines for carcinogenic risk assessment." Federal Register
¥9:46294, Nov. 23, 1984.
3. U.S. EPA, Office of Health and Environmental Assessment, "Pro-
posed guidelines for exposure assessment." Federal Register 49:463304
Nov. 23, 1984.
4. U.S. EPA, Office of Health and Environmental Assessment, "Pro-
posed guidelines for mutagenicity risk assessments," Federal Register
¥9:46314. Nov. 23, 1984.
5. U.S. EPA, Office of Health and Environmental Assessment, "Pro-
posed guidelines for the health assessment of suspect developmental
toxicants." Federal Register 49:46324, Nov. 23. 1984.
6. U.S. EPA, Environmental Criteria and Assessment Office, "Proposed
guidelines for the health risk assessment of chemical mixtures," Federal
Register 50:1170. Jan. 9. 1985.
7. ICF Incorporated, "Superfund public health assessment manual."
Draft for Office of Emergency and Remedial Response, Office of Solid
Waste and Emergency Response. U.S. EPA 1985.
8. Lyman, J., Rcehl, W F., Rosenblatt. D. H., editors, Handbookoj
Chemical Property Estimation Methods, McGraw-Hill, New York, NY
1982.
9. Schwarzenbach. R.P.. Molnars-Kubica, E., Giger, W. and Wakehan,
S.G. "Distribution. Residence Time, and Fluxes of Teirachloroeihyfcnc
and 1,4-Dichlorobenzene in Lake Zurich, Switzerland," Environ. Set.
Technol. 13:1919, 1367-73.
10. Thomas, R. G. "Volatilization from Water" in Handbook of Chemical
Property Estimation Methods (W. J. Lyman, W. F. Reehl, and
D. H. Rosenblatt) Eds., McGraw-Hill. New York. NY, 1982
II. Turner, D. B.. Workbook of Atmospheric Dispersion Estimates (IA
Printing, AP-26) U.S. EPA. Research Triangle Park, NC. 1974.
216 RISK ASSESSMENT/DECISION ANALYSIS
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Educational Needs for Hazardous Waste Site
Investigations: Technology Transfer in
Geophysics and Geostatistics
George T. Flatman
Evan J. England, Ph.D.
U.S. Environmental Protection Agency
Environmental Monitoring Systems Laboratory
Las Vegas, Nevada
Dennis D. Weber, Ph.D.
Environmental Research Center
University of Nevada, Las Vegas
Las Vegas, Nevada
ABSTRACT
The multi-disciplinarity of the science of hazardous waste site
investigation is placing an enormous demand on the site investiga-
tor who must be knowledgeable of the rapidly increasing gamut
of highly technical procedures being developed to meet the inves-
tigative needs of the field. This paper identifies the problems of
technology transfer and views it as a three-stage process involv-
ing the technological procedures, the technology transfer mech-
anisms and the site investigator. The three components are
analyzed, requirements specified and possible solutions suggested
to improve the process.
INTRODUCTION
Hazardous waste site (HWS) investigation is emerging rapidly
as a new multi-disciplinary science. Advancements are being
made by experts in many fields that contribute to the science.
These advancements, many in the areas of geophysics, statistics,
geochemistry and geohydrology, have the potential to aid the site
investigator in assessing the contamination at a site accurately and
cost-effectively. Several problems exist, however, that have
slowed the technology transfer from the experts who have devel-
oped the advancements to the site investigator who needs the
technology.
The magnitude and complexity of the contamination problem
imposes demanding qualifications on the site investigator. This in
turn suggests the need for a systematic program that facilitates
the technology transfer by making demands on the technology it-
self, the technology transfer mechanisms and the site investiga-
tors. The experts must develop generally applicable procedures
that solve real problems. Furthermore, the procedures must be
proven, documented and easily used by non-experts.
The software and hardware must be readily available along
with readable documentation and procedures manuals. The site
investigator must be made aware of this technology, and the
mechanism must exist to acquire the information. Finally, pro-
visions must be made to remove educational deficiencies that
might exist because of widely varying formal educations. This
paper uses examples from geophysics and geostatistics and draws
from the experience of the authors in presenting short courses to
describe the problems and techniques of technology transfer.
THEPROBLEM
Hazardous waste sites have posed a completely new set of prob-
lems to the technical world. The problems are difficult because
most of the contamination is below the surface of the earth. The
classical method of obtaining information is to drill a monitor-
ing well, collect groundwater samples and analyze the samples in
the laboratory. Monitoring wells, however, are expensive to drill
and maintain, are expensive and time-consuming to sample and
sometimes are destructive to the surface and subsurface. Proper
placing of the wells is difficult to assess, and obtaining enough
wells for statistical analysis is prohibitively expensive.
The magnitude and extent of the hazardous waste problem has
forced us to consider alternative methods of obtaining subsur-
face information. These methods, involving geophysical or soil
gas techniques, have some advantages over monitoring wells,
but, as in any new application of technology, they must be well
understood, proven and documented before they are of general
use. Finally, the information gained from the geologist, hydrolo-
gist, chemist and geophysicist (the "experts") must be consoli-
dated to give a meaningful representation of the data. This rep-
resentation often is cast as a contour map showing isopleths of
contamination level. The problem the investigator now faces is to
make the "BEST" map. This is the domain of geostatistics.
Geostatistics must provide not only the best map, but also a
second map that estimates the errors in the map of the contam-
inant's estimations. In some cases, geostatistics can give valua-
ble information about the spatial correlation of the contamina-
tion and, hence, about how the data should be or should have
been taken. Highly sophisticated techniques are being developed
to meet the problems of HWS, but the questions remain, how
does the site investigator know of their existence, whether they
are applicable or how to use them?
In this paper, geophysics and geostatistics will be used to ex-
plore the problems and possible solutions associated with the
above questions. One of the authors spent a year on the road pre-
senting a short course on Geophysical Investigations of Haz-
ardous Waste Sites' which included geostatistics as a topic. The
participants were mostly state and U.S. EPA personnel, with an-
other course given for contractors. Some of the observations
made while teaching these courses: (1) most of the participants
had no concept of what geophysics does or how it works,
and many considered it akin to water witching with a forked stick;
(2) a large percentage of the participants lacked the background
necessary to understand the subject; (3) under the circumstances,
a short course is entirely inadequate to do more than give the par-
ticipant some idea of what geophysics is; (4) most of the partici-
pants had not even heard of geostatistics.
In the case of geophysics and geostatistics, it is not difficult to
CONTAMINATED AQUIFER CONTROLS 217
-------
see where the problems lie. Geophysics is a multi-disciplinary field
that draws on physics and geology. In short, it uses sophisticated
remote sensing probes to extract information about the subsur-
face. The data obtained from these probes are subject to inter-
pretation and often must undergo complicated data processing
and modeling2 to extract the desired information. These tech-
niques, developed and used by experts, are rarely, if ever, docu-
mented such that a non-expert could learn them; they are devel-
oped principally by and for the mining and petroleum industries.
Comparable techniques are being developed by the U.S. EPA
for use at HWSs, but so far the same problem exists. Only the
experts, few in number, have the technical know-how.
Geostatistics, or spatial statistics, is being researched and devel-
oped for the Environmental Monitoring Systems Laboratory, Las
Vegas by top researchers in the field.' Developments are being
made in understanding the applications to HWS and special
algorithms (for example, soft kriging, indicator kriging and prob-
ability kriging) are being developed. The technology has been
developed and is being tested at HWS, but again, the site investi-
gator does not have easy access to sufficient information.
SUGGESTED SOLUTIONS
The solution to the technology transfer problem can be ap-
proached by considering the problem in three stages: (1) the tech-
nology itself, (2) technology transfer devices and (3) the site inves-
tigator.
Technology
To justify technology transfer, there must be conditions set for
the technology. First, it must prove that it solves a definable prob-
lem (i.e., it must be clearly capable of solving a real problem).
For example, geophysics has been used to map conductive
groundwater contamination using the Electromagnetic Induction
(EMI) technique. Before the technique is accepted, it must be de-
finable and it must prove under which conditions it can solve that
problem.
Next, the technique must be reduced to a defined procedure or
set of procedures. In an Electromagnetic Induction (EMI) study,
this means defining data acquisition, data processing and inter-
pretation procedures that are self-consistent and that provide in-
ternal and external checks to guide the investigative process. This
does not mean that a technique must be perfunctory or mechan-
ical. The key aspects of remote sensing are interpretive and prob-
ably never will be relegated to the "black box" concept. It means
that the process must make sense physically with respect to the
real world (external control) and it must be internally consistent.
An example of internal consistency in EMI is that the modeling
process requires statistical methods to make the output valid. If
the input is correct, the statistical output of the modeling provides
an internal check to tell if the mechanics of the modeling process
are working.
The procedure must be definable in terms understandable by
the site investigator, and the technique must be demonstrably cost
effective. In the case of geophysics, the quality of the results ob-
tained by an EMI survey must justify the cost of the investigation.
The final requirement to implement technology transfer is
ready accessibility of the necessary hardware and software. It
serves no practical purpose to suggest to the hazardous waste site
investigator a procedure that is proprietary or that is not generally
applicable. When the procedure is proven and completely devel-
oped, it must be packaged before the transfer process is initiated
so that it can be used by a site investigator.
Technology Transfer Devices
The next problem involves the mechanism for getting the infor-
mation from the technological experts to the site investigator. We
discuss: (1) procedures manuals; (2) short courses; (3) videotapes,
computer tutorials and expert systems; and (4) on the job train-
ing/consultation.
Of greatest general value is a well-written documentation of the
entire procedure, which we refer to as a procedures manual. The
procedures manual is a complete reference document for an inves-
tigative technique. It should contain enough theory to give the site
investigator an understanding of why the procedure is valid; it
also must tell in detail how to proceed from field-to-finish. Again
it must be emphasized that this does not mean that there u no
room for decision or inclusion of supplementary information.
The most successful investigation usually will be the one that in-
corporates results of several techniques into the final interpre-
tation.
The concept of a procedures manual is not new, but the paucity
of them is clearly evident if one attempts to learn about a new
technique. For example, there are several textbooks on the theory
of geophysical prospecting from which the adequately educated
can gain an understanding of the principles of the techniques.
Although it is necessary for the expert to have this understand-
ing, it does not mean he or she can apply that information to the
real problem.
A real problem (for example, shallow electrically conductive
contamination) has its own set of problems that must be studied
and solved. Many facets of such an investigation are gained by
experience, and an efficient operation must be developed. This
type of information seldom exists in a useable form.
Data processing of geophysical data is standard procedure, but
it requires an expert to determine which procedures are applic-
able to the hazardous waste site investigation, and it requires
considerable time and effort to develop the capabilities in-house.
Inverse Modeling,' the heart of geo-electrical sounding interpre-
tation, is necessary to interpret data from EMI and resistivity
measurements to obtain the subsurface structure. This proced-
ure, a computerized modeling technique used by professional
geophysicists but understood by very few, is, to the authors'
knowledge, not documented in an understandable form any-
where. In this case, a manual describing some theory, the bask
procedure and the input requirements as well as explaining the
statistical output would benefit the site investigator and the pro-
fessional geophysicist. This type of document is the first step in
bringing technology to the user. In each case where a technical
procedure has been identified, developed, tested and proven
useful, such a document must be produced as the first step in
the technology transfer.
A computerized procedure such as Inverse Modeling is an inter-
active procedure. This will be the case for any geoscience inter-
pretive procedure. Decisions will need to be made throughout
the procedure; in general, the greater the supplementary informa-
tion and experience of the interpreter, the better the interpreta-
tion. It is suggested that the procedure be explained to facilitate
appropriate decisions made with the most information possible.
For example, the computer inverse model requires statistical in-
formation in order to make the results valid. If that is under-
stood, the data acquisition can be optimally planned so that the
modeling has the highest chance of success. Furthermore, if the
results of the statistical analysis are understood, the interpreta-
tion is further aided. This information must be combined with
all other data from other sources (geochemical, hydrological.
geological, etc.) to make the final interpretation. Another im-
portant aspect of procedure establishment is standardization. A
procedure must be repeatable at a particular site by an inde-
pendent investigator, and the procedure must be defensible in
case of litigation.
218 CONTAMINATED AQUIFER CONTROLS
-------
Once the procedures manual has been written, there are many
ways to bring that information to the user. If the document could
be written to accommodate all levels of users having varying
educational and experiential backgrounds, the most effective
transfer mechanism would be distribution to all users. Such,
however, is not the case. A conclusion from the year of present-
ing short courses to U.S. EPA personnel is that the only assump-
tion that can be made about the user is that he or she has some
technical background and is capable and willing to learn. To im-
plement and enhance the technology transfer, a number of de-
vices are available.
Short courses can effectively supplement the procedures man-
ual. The manual should be available to the participant at least 1
month prior to the course, and time should be alloted to read and
digest the manual to the extent of the participant's ability. A
short course then would provide an opportunity to offer specific
information and explanations, to fill minor background defic-
iencies and to learn more about the needs of the participants.
The instructors must have actual experience in performing the
procedures and, if possible, must demonstrate the procedure
from field-to-finish. If this is not possible, a video tape should
provide the demonstration. Video tapes can provide illustrations
of actual field operations and other facets that are difficult to ex-
press in a written document. Finally, some sort of in-class evalua-
tion must be given to test the efficacy of the course and the level
of understanding of the participant. The length of the course
would depend upon the subject.
Computer tutorials and video tutorials can be used with the
manual and/or short course, or separately. The benefit of these
aids is well understood. Expert systems, however, play a different
role. The expert system is a popular topic in the field of comput-
ing and has the potential to become a significant mechanism for
technology transfer. The basic concept is not new; expert sys-
tems are essentially interactive computer programs that assist the
user working through a problem by prompting him or her to pro-
vide necessary data and by applying a set of pre-programmed
rules to this data to identify the best solution. What is new in
expert systems is a programming methodology, developed as a
result of research in "artificial intelligence." This methodology
permits the rules which apply to a particular problem to be en-
tered in a data table independent of the program which processes
the rules; rules can be added, deleted or modified without exten-
sively re-programming the system. It is, therefore, becoming more
practical to computerize such things as procedures manuals,
guidance documents, operating instructions, etc. The expert sys-
tem must degrade gracefully when queried beyond its rules and
must use feedback loops to learn new rules from previous ex-
periences. However, the expert system is only an aid to but not a
replacement for the expert. The U.S. EPA Office of Research
and Development has commited funds to evaluate the applica-
tion of expert systems to HWS. We can look forward to some
very interesting developments in this field in the next 4 years.
Finally, again supporting the theme that HWS Investigation is
an interpretive interdisciplinary science and that expert decisions
must at times be made, there must be access to experts. These
experts must be available either for consultation by telephone or
to provide on-the-job training. An investigation should not be
completed without the capability of consultation with an expert.
Preferably, on-the-job training would be provided to guide the
investigators trained by the above methods through the first in-
vestigation. This last step would close the loop in the transfer
from expert to practitioner and would provide the opportunity
for the expert to fine-tune the method to the application.
Site Investigator
Finally, a few comments must be made about the investiga-
tor. The educational backgrounds of the HWS investigators are
varied and include biology, geology, hydrology, business, phys-
ics, art, etc. It is easy to see that the difficulty of implementing
technical procedures will vary greatly according to the back-
ground of the investigator. This is a matter over which there is
very little control; however, a reasonable approach would be to
recommend appropriate university courses for those lacking the
appropriate technical background. This requirement would be
most feasible in locations close to a university campus. Some
universities offer appropriate short courses during the summer.
Another long-range solution would be to offer scholarships to
students to train in specialties that are needed for HWS inves-
tigations.
CONCLUSIONS
Presently, many new technical methods have been and are
being developed for HWS investigations. These methods are
understood by only a few researchers, i.e., the experts, and very
little if any information is shared with the site investigator
charged with the responsibility of evaluating the contamination.
These technical methods must be fully developed, tested and
proven useful and cost-effective.
Next, the methods must be completely documented so that they
can be understood and executed by the properly educated site
investigator. The wide range of educational and experiential
backgrounds of the investigators requires a more complete pro-
gram of technology transfer including short courses, video and
computer aids and the close interaction of the experts with the in-
vestigator during early stages of the learning process. The Haz-
ardous Materials Control Research Institute has been a pioneer
and pace-setter in this multi-disciplinary technical transfer by
making available a forum in the annual Superfund Conferences.
DISCLAIMER
The information in this document has been funded wholly or
in part by the U.S. EPA through a cooperative agreement,
CR812189, with the University of Nevada, Las Vegas, Nevada.
It has not been subjected to Agency review and, therefore, does
not necessarily reflect the views of the Agency and no official en-
dorsement should be inferred.
REFERENCES
1. Evans, R.D. and Weber, D.D., A short course "Geophysics for
Hazardous Waste Site Investigations." Presented to 16 state and
U.S. EPA offices, and to the National Water Well Association once
as a training course, 1984-1985.
2. Weber, D.D. and Flatman, G.T., "Statistical Approach to Ground-
water Contamination Mapping with Electromagnetic Induction: A
Case Study," Surface and Borehole Geophysical Methods and
Groundwater Instrumentation Conference of the National Water Well
Association, Denver, CO, October 1986.
3. Flatman, G.T. and Yfantis, A.A., "Geostatistical Strategy for Soil
Sampling: The Survey and the Census." Environ. Man. and Assess.
4(1984)335-349.
4. Weber, D.D., Flatman, G.T. and Koebke, T.H., "Subsurface Con-
tamination Mapping from EMI Soundings," Proc. of the HAZTECH
International Conference and Exhibition, Denver, CO, 1986.
CONTAMINATED AQUIFER CONTROLS 219
-------
A Collection/Treatment/Recharge/Flushing
Groundwater Remediation Program
Kurt O. Thomsen, Ph.D., P.G.
Bakulesh H. Khara, P.E.
P.R.C. Engineering, Inc.
Chicago, Illinois
Aloysius A. Aguwa, Ph.D.
General Motors
Warren, Michigan
ABSTRACT
Volatile organic compounds usually associated with spent sol-
vent disposal were identified as the contaminants in an uncon-
fined glacial outwash aquifer. As a result of a remedial inves-
tigation/feasibility study, a remedial action alternative was
selected.
The selected alternative included a combination of ground-
water collection, treatment and recharge and soil flushing. The
collection system withdraws the groundwater from several levels
in heavily contaminated areas. This water is diluted with water
collected from a system of wells that prevents the migration of
contaminants to an adjacent river. The groundwater will be
treated using an induced draft air stripper. Effluent from the
stripper will be spread in a recharge area located over the heavily
contaminated areas. Additional treatment of volatile organics will
be provided by natural volatilization as the water percolates into
the ground. Prior to being recycled, recharge water will move
downward through the contaminated soils flushing the residual
contaminants.
Pump and pilot testing conducted prior to construction re-
sulted in several design changes. These included an increase in the
amount of groundwater treated, a change in the treatment hard-
ware specified and a redesign of the system to distribute the
treated water over the recharge area.
INTRODUCTION
A manufacturing facility is located on the lower of two penin-
sulas formed by a reverse "S" meander of a river (Fig. 1). In the
late 1960s the local regulatory agencies granted permission to the
manufacturer to use the upper peninsula as a waste disposal
area. As a result of the change in the environmental regulatory
atmosphere in the 1970s, a consent judgment was negotiated be-
tween the state and the manufacturer providing for the cleanup
and remediation of the waste disposal area.
Fig. 2 shows the areas where the major disposal activities took
place. Three paint sludge pits were located in the area of monitor-
ing well 2 (MW-2). A cache of drums was buried just west of
MW-2; drums also were placed in a ravine located in the western
portion of the site north of MW-3. The central portion of the site,
between MW-1 and MW-2, was the location of numerous batch
spills and general disposal of solid wastes.
Site cleanup was conducted in 1981. At this time, 1500 drums
were removed from the ravine, while another 1200 were removed
from the cache located west of MW-2. Approximately 2700 yd'
220 CONTAMINATED AQUIFER CONTROLS
of paint sludge and associated contaminated soils were excavated
from the three paint sludge pits. In addition, 27,300 yd* of con-
taminated soils were excavated from the central portion of the
site and the drum areas.
Figure 1
Site Plot Plan
Remedial Investigation
The remedial investigation was conducted in three phases.
The first phase was the exploratory phase during which six well
nests were installed (MW-1 to MW-6). As a result of this activity,
the general site stratigraphy was defined. Five major hydrogeo-
logic units were identified. The uppermost unit is an unconnned
glacial outwash aquifer which is in communication with the river.
-------
UTUN OF UOMTOKMO
Figure 2
Locations of Disposal Areas
Within this unit in the western portion of the site is a lacustrine
aquiclude. Remnants of this aquiclude also were found in the
eastern portion of the site. Underlying this upper outwash aquifer
is a substantial glacial till aquiclude followed in order by an-
other glacial outwash aquifer, a glacial till aquiclude and a glacial
outwash aquifer which was encountered in one borehole at an
approximate depth of 150 ft below grade.
During the second phase of the remedial investigation, it was
determined that all contamination was confined to the upper out-
wash aquifer and that trichloroethylene (TCE) was the dominant
contaminant at the site. As a result, TCE was selected as the in-
dicator compound used to monitor site cleanup.
A third phase was instituted to better define the stratigraphy of
the central portion of the site where most of the disposal activities
took place in preparation for designing the groundwater collec-
tion system. The major hydrogeologic units encountered during
this third phase study were the upper outwash aquifer and the
underlying upper till unit. Within the upper outwash aquifer are
lenses of various combinations of fine materials which act as
aquitards or aquicludes. These lenses form the aquiclude/aqui-
tard units and are found at many levels and varying areal ex-
tents throughout the upper outwash aquifer. The majority of
these units seem to be grouped at elevations of 805 and 790 ft
(grade elevations range from the river elevation of 811 to 835 ft).
The two identified aquiclude/aquitard layers exhibit variable
hydrological characteristics. This variability is reflected by the
fact that at some locations the 805 layer exists but not the 790
layer, and vice versa. At several locations, the 805 and the 790
layers are one unit, while at other locations neither exists. In addi-
tion, some locations have layers at other levels within the upper
outwash aquifer which do not correlate with either the 805 or the
790 layers.
The movement of groundwater within the upper outwash
aquifer is complex. Groundwater flows to the river and vertical-
ly around and through the aquiclude/aquitard layers. The upper
outward aquifer was divided into the upper, middle and lower
portions. The upper portion of the aquifer roughly lies between
the water table (811.0 to 812.5 ft) and the 805 layer. The middle
portion lies between the 805 and the 790 layers, and the lower por-
tion lies between the 790 layer and the upper till aquiclude.
Lateral groundwater movement on the site is directed toward
the river from a groundwater high located between MW-1 and
MW-2. This same pattern generally is reflected in the flow pat-
terns of the three levels. Vertical groundwater movements are up-
ward to the river along the site boundary. Upward and down-
ward groundwater movements have been identified at various
locations and over a variety of the hydrogeologic units.
As described above, the complex nature of the site stratigraphy
is responsible for the variability of the horizontal and vertical
groundwater flow pattern and, thus, is the major factor determin-
ing the contaminant migration pathways. Once the stratigraphy
was well defined, the design of a groundwater collection system
became a relatively straightforward task.
Feasibility Study
The feasibility study was a relatively straightforward proced-
ure because of the limited options available for consideration.
The groundwater had to be collected, treated and discharged.
The options for collection included number of wells, depth of
wells and the amount to be pumped. Pump tests were needed
before the proper selection could be made. Air stripping was
selected as the treatment process due to its recognized lower cap-
ital, operation and maintenance costs. Discharge to the adjacent
river was the obvious solution, but it was decided to put the
treated discharge to work by recharging the discharge in the area
where most of the disposal activity took place. Recharge and the
recycling of the water would act to flush the residual contami-
nants from the soils.
Once these basic decisions were made, a pilot study was insti-
tuted to better define and determine the feasibility of the selected
alternatives. Pump tests were conducted to help define the collec-
tion system. In addition, pilot treatment and recharge tests were
conducted.
COLLECTION
Pumping tests were conducted in five pumping wells at three
locations and at two depths. The pumping well locations are
designated PW-1 to PW-3 on Figure 2. The two depths coin-
cided with the upper and middle portion of the upper outwash
aquifer. Contamination within these two portions of the aquifer
was documented during the third phase of the remedial investiga-
tion. Location PW-1 was chosen because it was representative
of the central spill area. PW-2 was chosen to be within the iden-
tified contamination plume extending from the waste disposal
area to the river, and PW-3 was chosen to represent conditions in
the paint sludge pit area.
All pump tests were 48 hr long; a minimum of 4 and a max-
imum of 6 observation wells were monitored during each test. Ob-
servation wells screened at depths other than the pumping depth
were included in the group of wells monitored for each test. These
wells were included so that the effect of pumping on other por-
tions of the aquifer could be evaluated. A summary of the pump
testing results is presented in Table 1.
TREATMENT
The major contaminant identified in the groundwater through
the above mentioned remedial investigation is trichloroethylene
(TCE). Based on the physical and chemical properties of this vol-
atile organic compound, the two treatment processes suitable
for its removal from water are air stripping and carbon adsorp-
tion. Although these two treatment processes are both feasible
and dependable, air stripping was selected due to its recognized
lower capital, operation and maintenance costs.
Having selected the type of treatment process applicable, the
next phase was to determine the optimum engineering parameters
for design. Accordingly, treatability studies were planned and ex-
ecuted. An induced draft air stripper equipped with nozzles hav-
ing an air-to-water ratio of 575 was used for the treatability study.
While the air-to-water ratio remained constant during each exper-
imental run, the environmental air temperature did vary. Temp-
CONTAMINATED AQUIFER CONTROLS 221
-------
erature variation is expected during the actual treatment opera-
tion.
The objective of the treatability study was to obtain design data
by simulating the actual treatment process. Accordingly, all ex-
periments were conducted with full-scale equipment using the
contaminated groundwater at the site. For the induced draft
stripper, the objectives were to determine the removal efficiency
and the number of strippers needed to attain a treatment level
less than or equal to 15 jig/L of TCE. Another objective was to
determine the number of passes required to achieve the treat-
ment level using only a single induced draft stripper.
Fig. 3 depicts the field experimental setup. First, groundwater
at a temperature of 55 °F was pumped to fill the lower reservoir
(Tank #1, approximately 500 gal). The groundwater then was
pumped up to the stripper, circumventing the nozzles, and
allowed to gravity flow to the upper reservoir (Tank tfl, approx-
imately 500 gal) and then to the lower reservoir where it was re-
cycled back to the stripper. This was done for about 10 min to
equilibrate the system. After equilibration when the lower reser-
voir was filled, two samples were taken and measured for TCE
concentration. The average TCE level in the two samples was
designated as the initial concentration, or C0. The water in the
lower reservoir was then pumped (40-50 gal/min) through the
stripper nozzles, and the effluent was collected in the upper reser-
voir. After all the water had passed through the stripper and into
the upper reservoir, two samples were taken for analysis from a
sampling bibb. The average level in the two samples was desig-
nated as effluent concentration, or Ce. The removal efficiency
was calculated as follows:
r QLOae VAIVB FO* THROTTLING
removal efficiency =
Co-Ce
x 100
(1)
The above procedure was repeated for the number of times re-
quired to achieve the treatment level.
RESULTS
Fig. 4 depicts typical results of the stripping action system. The
concentrations as a function of the number of passes through the
stripper are plotted. These results indicate that almost all the TCE
in the water can be removed. However, to achieve the near zero
effluent concentration, five passes through one stripper or one
pass through five strippers in series are required. Fig. 5 shows the
cumulative removal efficiency versus number of passes. As prev-
iously indicated, this type of plot can be used to determine num-
ber of passes required to achieve a desired removal. As was veri-
fied in the field, higher TCE levels (greater than 400;jg/L) would
require greater number of passes to achieve a near zero concen-
tration level. The reverse is true for lower concentrations.
• l/f SAMPLING
AND OHAH4
1/2* AIR ft
VACUUM COMB
VALVE r*
m
^
ii
i AII Dicing ind »aiv«i • 2* accept t/2* air and vacuum, and 1/2*
bibb (Maiif 2*]
2 Proctii pu«K> SO 9Om al 55 pal(mto).
3 Gravity flow Ironv air alrleper to Tank *2. and Tank *J (o Tank *1.
or ball valva (depending on coil).
Figure 3
Pilot Plant Schematic
400r
|\
300 -j \
o
iaoo
z
UJ
O
O
U
UJ
U
200
100
• INFLUENT TCE: 370 mg/L
OVERALL REMOVAL: 99.9X
A INFLUENT TCE: 400mg/L
OVERALL REMOVAL: 99k
TEMPERATURE: UPPER 70s
AIR/WATER: 575
WATER FLOWRATE: 53 GPM
^ "* = =:*
2 3
NUMBER OF PASSES
Table I
Pumping Characteristics
Figure 4
Effluent TCE Concentration as a Function of the Number of Passes
Well
PW-IA*
rw-jB
rw.jA
PW-3B
*Thciuffix "A"
denotes a pumpini
Triairainlvily
dii/^i, ro
M900
12400
14500
19*00
10100
Slomivity
(unities!)
0.0041
0.000015
00000)
0.0)]
0.00047
Locll
Bouadiry
CaBdilloa
rtchlfgc
InpfrneBble
itch., |t
denotes a pumping well screened in the upper portion i
i well screened In the middle portion of the aquifer
Loot
AQWlTcf
leiky co.fimd
leahy coaflned
>r (he aqullci and "D
RECHARGE
A 20- by 40-ft pilot recharge area was constructed on-site. The
area was excavated, leveled, filled with pea gravel to a depth of
approximately 1.0 to 1.5 ft and bermed. The gravel was used to
provide greater distribution of the treated water and to provide
additional air/water contact before the water infiltrated into the
ground.
Several methods were used to distribute the treated ground-
water on the gravel bed. These methods ranged from using per-
forated flexible field tile to using a rigid system constructed of
222 CONTAMINATED AQUIFER CONTROLS
-------
100
> 90
ui
5
tZ
u.
UJ 80
_j
O
u
cc 70
ui
_l
60
50
. FROM PUMPING WELL
OR PILOT PLANT
• INFLUENT 370 mg/L
OVERALL REMOVAL: 99.9%
A INFLUENT 400 mg/L
OVERALL REMOVAL: 99%
TEMPERATURE: UPPER 70s
AIR/WATER: 575
WATER FLOWRATE: 53 GPM
2 3
NUMBER OF PASSES
Figure 5
Cumulative Removal Efficiency as a Function of the Number of Passes
PVC pipe equipped with spray nozzles. The latter method proved
to be the most effective, both in terms of efficiency and cost. Fig.
6 shows both a plot plan and a cross-section of the pilot recharge
area using the spray distribution system. In constructing the spray
distribution system, the gravel bed provided direct structural sup-
port. The spray nozzles were directed upward to provide optimal
distribution of the treated water over the recharge bed and to op-
timize residence time for additional air stripping of the TCE.
This additional air stripping removal efficiency was 94% at an
ambient temperature of 77 °F (Table 2). Removal of 79% of the
influent TCE was achieved between the time the water left the
nozzles and the tune it came in contact with the gravel bed. An-
other 15% removal was achieved as the water traveled through
the gravel bed.
Table 2
TCE Removal in Groundwater Distribution/Recharge System
Influent to
Diitribution
System
Influent to
Grivel Bed
Effluent from
Grivel Bed
Avenge
TCE
Concentration
(ui/L)
95 Percent
Confidence
Limili
Removtl
Efficiency
(*)
Overall Removil Efficiency: 93.9%
FLUSHING
Due to the complex nature of residual soil contamination, no
pilot studies were conducted addressing the flushing of the con-
taminants from the soils. The flushing of contaminants from the
soils will be a direct result of a combination of treated ground-
BERM
p
^2* PVC HEADER
NOZZLES*
N
V
COLLECTION
\ZSr PAN \
\
x \
:X-'J
RECHARGE AREA
y u
~^* — — — -, ^JTT7» '
I
uA
• 2- PVC -.
LATERALS c
\
f
10'
I
y
PLAN
FLOW INTERCEPTION SYSTEM
CROSS SECTION
Figure 6
Pilot Recharge System
water recharge and groundwater collection. The groundwater
collection system will facilitate the movement of the treated water
through the contaminated soils. The effectiveness of this remedia-
tion system will be evaluated by monitoring the TCE concentra-
tions of influents from wells in key areas over time.
CONCLUSIONS
The results of the remedial investigation and feasibility study
indicated that the remedial program being evaluated is feasible.
However, the complex nature of the disposal area stratigraphy
will require a larger number of collection wells than originally
estimated. These wells will be placed at two levels. The collec-
tion system will be designed to collect contaminated ground-
water and prevent its migration to the adjacent river. The system
also will provide a flushing mechanism for the soils. It is esti-
mated that a combined pumping rate of 600 gal/min would be
optimal for the system.
The study also indicated that the desired level of TCE removal
can be achieved using a series of induced draft air strippers or a
combination of the tested induced draft air stripper with the dis-
tribution and recharge system. Since the expected flow to the
treatment plant is much higher than the previously anticipated
flow (600 gal/min compared to 30-60 gal/min), 12 air strippers
of the type used in the pilot study would be required to treat the
expected flow. A re-evaluation of the proposed use of the in-
duced draft air stripper is warranted because of the large num-
ber of strippers needed.
Finally, the pilot studies showed that the treated groundwater
distribution and recharge system is very efficient and cost effec-
tive and, under certain circumstances, could stand alone as a
groundwater treatment system.
CONTAMINATED AQUIFER CONTROLS 223
-------
Establishing and Meeting Ground water Protection
Goals in the Superfund Program
Edwin F. Barth III
Bill Hanson
Elizabeth A. Shaw
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Washington, D.C.
ABSTRACT
A decision process for identifying, evaluating and selecting
Superfund groundwater response actions is currently being devel-
oped by the Superfund Program. The process applies the
Agency's Oroundwater Protection Strategy and is a flexible rem-
edy selection and re-evaluation process that allows for more effec-
tive decision-making at the Record of Decision stage. The goal of
this decision process is to return usable groundwater to beneficial
use within a time-frame that is reasonable given the particular cir-
cumstances of the site.
INTRODUCTION
Decisions on contaminated groundwater at uncontrolled haz-
ardous waste sites are complicated due to complex fate and trans-
port patterns. The process being developed will guide Remedial
Project Managers (RPMs) and other decision-makers concerned
with groundwater remedial actions at Superfund sites so thai a
consistent groundwater evaluation and decision approach is
applied to all Superfund sites.
APPLICABLE OR RELEVANT AND
APPROPRIATE REQUIREMENTS
Under the NCP,' remedial actions at Superfund sites shall meet
or exceed all applicable or relevant and appropriate Federal re-
quirements and consider other pertinent Federal criteria, advisor-
ies and guidance and state standards. (This paper was prepared
prior to CERCLA reauthorization. In the event of a new statute
certain aspects of the cleanup standards discussion may be al-
tered.) The Federal requirements that may be most applicable,
relevant or appropriate to Superfund groundwater actions are
the RCRA Subpart F regulations. Determinations of ground-
water protection levels under both RCRA and Superfund may
be based on a site-specific risk assessment.
The Safe Drinking Water Act and the Clean Water Act resulted
in the development of maximum concentration levels (MCLs),
recommended maximum concentration limits (RMCLs), health
advisories and water quality criteria for protection of public
health which may be evaluated for groundwater protection levels
in the Superfund program. The U.S. EPA's Groundwater Pro-
tection Strategy is an important component of Superfund's
groundwater approach. The strategy says that ground waters
should be protected differentially based on characteristics of vul-
nerability, use and value.
Special groundwaters (Class I) are those that are highly vulner-
able to contamination because of the hydrological characteristics
of the areas where they occur. They are characterized by either
of the following factors:
• The groundwater is irreplaceable because no reasonable alter-
native source of drinking water is available to substantial pop-
ulations
• The groundwater is ecologically vital, by providing the base
flow for a particularly sensitive ecological system that, if
polluted, would destroy a unique habitat
Current use groundwaters (Class II A) and potential use
ground waters (Class II B) that are sources of drinking water (or
other beneficial uses) include all non-Class I groundwaters that
are currently used or are potentially available for drinking water
or other beneficial use.
Groundwaters not considered potential sources of drinking
water and of limited beneficial use (Class III) are non-usable
groundwaters which are highly saline, i.e., they have total dis-
solved solids (TDS) levels over 10,000 mg/1, or are otherwise
contaminated beyond levels that allow cleanup using methods
reasonably employed in public water treatment systems. This con-
dition must not be the result of a single waste site, but must be the
result of a wide range of sources. Class III is further separated by
the degree of inter-connection with adjacent water. Class III A
groundwaters are highly to moderately inter-connected and are
thus most relevant to Superfund. Class III B groundwaters have a
low degree of inter-connection and are typically at greater depths.
As will be explained in this paper, the Superfund program will
use these groundwater characteristics in the evaluation of alterna-
tive response actions.
DEVELOPMENT OF GROUNDWATER
ALTERNATIVES
In general, source control measures should facilitate the
achievement of long-term remediation objectives and goals for
groundwater. The Guidance Document for Feasibility Studies
Under CERCLA1 calls for the development, screening and de-
tailed evaluation of alternatives proposed for remedial actions.
For groundwater contamination problems, this process involves
the development of a limited number of remediation alternatives
to be presented to the decision-maker.
The performance goal of each groundwater alternative should
be expressed in terms of a cleanup concentration (in the ground-
water) and a time period for restoration for all locations in the
area of attainment. Concentration levels may be derived from
health based criteria such as excess unit carcinogenic risk (UCR)
or reference dose values. These levels may be available or be de-
rived from MCLs, RMCLs, health advisories or water quality cri-
teria. Health based criteria also may be developed if no stan-
dards, advisories or criteria are available. The reader is referred to
224 CONTAMINATED AQUIFER CONTROLS
-------
the Superfund Public Health Evaluation Manual3 for information
on developing health based criteria. Restoration time periods may
range from very rapid (1 to 5 years) to relatively extended (per-
haps several decades).
If Class I or II groundwaters are contaminated with known or
suspected carcinogens, the program desires that a limited num-
ber of groundwater protection goals be developed that vary be-
tween 10"4 UCR and 10~7 UCR and vary between restoration
time periods. A point of departure alternative for initial decision
evaluation should be developed at a 10 ~6 UCR and 1- to 5-year
restoration time period. For non-carcinogens, alternatives should
be developed that meet chronic or acute threshold levels in vary-
ing restoration periods.
In situations where the plume is not close to a receiving body of
water, plume containment measures (such as gradient control)
also should be evaluated which eventually will result in a 10 ~4
UCR and 10~6 UCR for carcinogen levels in the groundwater. A
limited number (possibly two to three) of other alternatives also
should be developed around the point of departure. Fig. 1 pre-
sents a conceptual risk/restoration time plot of these suggested
alternatives for carcinogens contaminating groundwaters with
Class I or II characteristics.
These alternatives then will be evaluated to compare the trade-
offs between the cleanup level, time to the achieve level and cost
of the action.
REMAINING
GROUND WATER
CONTAMINANT
CONCENTRATION
Actual
Performance
Predicted
Performance
DURATION OF REMEDIAL ACTION
Case 3A Ground Water Goal will be achieved
REMAINING
GROUNDWATER
CONTAMINANT
CONCENTRATION
DURATION OF REMEDIAL ACTION
Case 3B Ground Water Goal will be achieved
in longer time frame
Noli: Nondrclnonnl will hid i Ihrllhold
In* Ihlt il nol (llilMl.
Figure 1
Suggested Alternatives to be Developed for
Groundwater Contaminated with Carcinogens
l e
I...I 10'5
Hor urcinoginil
Minimum Alllrnllivll Ricommlndld lor
A Minimum AlKrnllivll
T Dlllilld E»llun.on
iBIunl Altenuition/Cor
REMAINING
GROUNDWATER
CONTAMINANT
CONCENTRATION
DURATION OF REMEDIAL ACTION
Case 3C Ground Water Goal will not be achieved
over long period of time
Figure 2
Performance Range for Groundwater Remedial Alternatives (General)
LEGEND
* Remedial Action Performance Goal
* Time of Performance Evaluation
Figure 3
Possible Restoration Scenarios When Evaluating Performance Data
CONTAMINATED AQUIFER CONTROLS 225
-------
DECISION ANALYSIS
Selecting and implementing a remedial action alternative de-
pends upon many factors. Those factors relating to the concen-
tration level for carcinogens in the groundwater are:
• Other health risk borne by the affected population
• Population sensitivities
For example, at the Reilly Tar Superfund site, the population
had been exposed to contaminated groundwater for an undeter-
minable period of time; this unknown exposure influenced the de-
cision to use a "more protective" concentration level. Similarly,
a more protective concentration level may be evaluated if the ex-
posed population is unusually sensitive to the contaminants.
Acute and chronic levels for non-carcinogens are threshold values
and, therefore, are not influenced by these two factors.
Factors that influence the restoration time period for ground-
waters contaminated with carcinogens and non-carcinogens are:
Feasibility of providing an alternative water supply
Current use of groundwater
Potential need for groundwater
Effectiveness and reliability of institutional controls
Ability to monitor and control the movement of contaminants
in groundwater
If there are other readily available drinking water sources of
sufficient quality and yield that may be used as an alternative
water supply, the importance of rapid restoration of the contam-
inated groundwater is reduced. Where a future demand for drink-
ing water from groundwater is likely and other potential sources
are not sufficient, those remedies which achieve more rapid res-
toration should be favored.
The effectiveness and reliability of institutional controls to pre-
vent the utilization of contaminated groundwater for drinking
water purposes should be evaluated. If these controls are not
clearly effective, rapid restoration may be necessary.
In some circumstances, complex flow patterns increase the
potential for unanticipated migration pathways and may reduce
the effectiveness of remedial action. Remedial actions that will
rapidly restore groundwater should be emphasized in these situa-
tions.
Other factors that should be considered in determining the ap-
propriate groundwater protection goal for carcinogens and non-
carcinogens are:
• Limiting extent of contamination
• Impact on environmental receptors
• Technical practicability of implementing the alternative
• Cost of alternative
Limited increases in concentration may be evaluated if the ex-
panded area is relatively small, the time period of degradation is
short and the ultimate discharge of the plume has no significant
effect on surface waters.
The technical practicability of each alternative must also be
evaluated in light of the contaminant characteristics and hydro-
geological conditions which may not allow effective implementa-
tion of the alternative to clean up the groundwater.
Environmental receptors should be taken into account when
evaluating the appropriate cleanup concentration levels and time
period.
Finally, under the NCP, response actions must be cost-effec-
tive. Therefore, a careful evaluation of capital outlays and oper-
ation and maintenance costs associated with each alternative
must be considered and compared to those of each of the other
alternatives. Groundwater goals may not be met if high costs in-
voke fund balancing.
Fig. 2 presents general groundwater goal areas associated with
Figure 4
Flexible Decision Process for Groundwater Remedial Actions
the groundwater characteristics on the risk/restoration plot for
carcinogens. The decision-maker should first evaluate the point
of departure remedy and then move to other general areas on the
plot as influenced by the groundwater characteristics. The reader
should be cautioned that the general areas delineated on the plot
are not rigid.
FLEXIBLE DECISION PROCESS
Complex fate and transport mechanisms of contaminated
groundwaters often make accurate predictions of the perfor-
mance of the groundwater remedial action difficult. Therefore,
the remedial process must be flexible and allow changes in the
remedy based on the performance of several years of operation.
To illustrate this variability in results and concomitant need
for flexibility. Fig. 3 presents three possible situations that may
occur after several years of a groundwater response action. In
the first scenario (Case 3A), the target concentration will be
reached within the desired time period; in the second scenario
(Case 3B), the target concentration will be reached somewhat
later than the desired time period; and in the final scenario (Case
3C), the target concentration will not be reached in a foreseeable
time period.
A performance feed-back concept has been incorporated into
the decision process so that in situations where the performance
goal will not be met (such as Case 3B and Case 3Q, the decisions
may be re-evaluated based on actual experience. If the imple-
mented remedial action is not meeting expectations, the decision-
maker should decide the extent to which further or different
action is necessary and appropriate to protect human health and
the environment; Fig. 4 illustrates this evaluation process. Should
it be impracticable to restore the groundwater to the initial clean-
up goal, an exception to the NCP for meeting applicable or rele-
vant and appropriate Federal requirements such as Fund bal-
ancing or the technical impracticability waivers could be demon-
strated.
REFERENCES
1. Fed. Reg., Nov. 20, 1985.
2. U.S. EPA, "Guidance Document on Remedial Investigations
and
Feasibility Studies Under CERCLA," prepared for HWERL, OERR,
OWPE, Washington, DC, June 1985.
3. U.S. EPA. "Superfund Public Health Evaluation Manual" (draft),
prepared for OERR, Washington, DC, Dec. 1985.
226 CONTAMINATED AQUIFER CONTROLS
-------
Pitfalls of Geophysics in Characterizing
Underground Hazardous Waste
William J. Johnson
Paul C. Rizzo Associates, Inc.
Pittsburgh, Pennsylvania
Donald W. Johnson
CH2M HILL
Milwaukee, Wisconsin
ABSTRACT
Several geophysical techniques, including magnetics, electrical/
electromagnetics, seismic refraction and ground probing radar,
frequently are applied to hazardous waste investigations. De-
pending on the nature of the problem, these techniques have been
used successfully to trace groundwater contamination, locate bur-
ied drums, map the location and extent of pits and trenches and
assess the general geologic setting of a site. However, many re-
searchers find that the methods often do not work or can be mis-
leading.
In some cases, cultural or natural "noise" or terrain con-
ditions preclude successful surveying. However, the most im-
portant problems occur because of inexperienced operators and/
or interpreters. The main conclusion of this study is that, when
properly applied by experienced personnel, geophysics is a neces-
sary and useful tool in a hazardous waste site investigation. With
a minimum amount of site information, the geophysicist usual-
ly can assess the probability of success of a given technique and
define an effective program of study. Some locations are so ad-
verse that geophysical techniques are not appropriate, but such
locations can be defined in advance.
INTRODUCTION
Much of the current experience in applying geophysical tech-
niques to hazardous waste investigations is negative. The results
of the investigations often fall short of what is expected and, in
some cases, can yield misleading results. Some of the problems
frequently encountered include:
• Incorrect Method Applied—Possible causes include lack of
understanding of geophysical technology by the planner (a
non-geophysicist), or a lack of understanding of site con-
ditions or the objectives of the survey.
• Poor Data Quality—Possible causes include high ambient
noise, poor field procedures, improper use of equipment,
faulty equipment, adverse geologic conditions or inexperienced
operators.
• Poor Interpretation—The problem of interpretation is fre-
quently the use of an inadequate interpretation method, hav-
ing insufficient background information or insufficient or
noisy data.
• Insufficient Data—Possible causes include a lack of under-
standing of methods and/or site conditions and objectives,
operator inexperience, lack of up-to-date plotted data in the
field (some contractors gather data but do not plot it or look
at it until they are back in the office).
The situation is serious. One researcher' estimates that with one
technique alone (DC resistivity) about 40% of the surveys for the
evaluation of groundwater contamination were not successful or
obtained only limited results. This estimate may be optimistic.
The experience of some organizations is so bad that the use of
geophysics in a site investigation is virtually banned.
The intent of this paper is to highlight the authors' experience
with problems that commonly are faced with the surface geo-
physical techniques most commonly employed during investiga-
tions of groundwater contamination and hazardous waste.
Emphasis has been placed on defining the limitations of apply-
ing geophysics, considering factors such as cultural or natural
"noise," terrain conditions, resolution and common mistakes
made due to the inexperience of operators and/or interpreters.
Examples are provided from real case histories where methods
were not successful or where data were misinterpreted (for ob-
vious reasons, confidentiality has been maintained). Comments
are provided to highlight the pitfalls that can trap the unwary re-
searcher.
PITFALLS OF DIFFERENT
GEOPHYSICAL TECHNIQUES
The main surface geophysical techniques applied to hazardous
waste and groundwater investigations include DC resistivity,
electromagnetics (EM), magnetics, ground probing radar (GPR)
and seismic refraction. Details of the theory and applications of
these methods are beyond the scope of this presentation and the
reader is referred to publications such as the book Geophysical
Techniques for Sensing Buried Wastes and Waste Migration,2 for
a general introduction and the proceedings of the NWWA/U.S.
EPA conferences on "Surface and Borehole Geophysical
Methods in Groundwater Investigations,"3'4 for more detailed
information. These techniques are discussed separately.
DC Resistivity
DC resistivity is one of the most widely applied methods of
engineering geophysics. The basic field and interpretive proced-
ures have been known since the beginning of this century. Equip-
ment is relatively inexpensive and readily deployed in the field
with little operator training. This last characteristic also works to
the disadvantage of the technique.
DC resistivity measurements usually are made by measuring the
voltage drop between two electrodes in the ground after an elec-
trical current has been induced in the ground between two other
electrodes. The most commonly applied electrode configura-
tions are referred to as the Wenner and the Schlumberger array.
In the Wenner array, the electrodes always are separated by a
constant distance called the "A" spacing. With the Schlum-
berger array, the voltage electrode spacing is constant while the
current electrode spacing is variable.
CONTAMINATED AQUIFER CONTROLS 227
-------
Electrical "soundings" obtain information on the vertical var-
iation of electrical properties by expanding the electrode spread.
Electrical profiles are obtained by moving a fixed electrode spread
along a survey line in order to define lateral variation of sub-
surface electrical properties. Ultimately, the data are used to de-
rive electrical models of the subsurface which can be related to
the presence of contaminated plumes (dissolved contaminants
frequently cause groundwater to have an abnormally low resis-
tivity) and buried wastes.
All of the generic difficulties inherent in conducting a geo-
physical survey outlined in the introduction are applicable to DC
resistivity. Pitfalls specific to this method are outlined as follows:
• Improper Selection of Technique—Unless ground conditions
are fairly simple, the use of the Schlumberger array is nearly
always preferable to the Wenner array. The Wenner array
can have excessive problems due to lateral resistivity varia-
tions to which the Schlumberger array is less sensitive.
• Improper Equipment—The equipment should be capable of in-
ducing adequate current in the ground. Low-frequency AC is
preferable to pure DC.
• Difficult Terrain—The presence of a highly resistive surficial
soil (e.g., dry sand, frozen ground), presence of surface con-
ductors (e.g., fences or railroad tracks), underground metal
pipes or any buried metal will cause difficulty. Meaningful re-
sistivity results should not be expected from the top of a land-
fill.
• Poor Field Procedure—Careful field notes should be made to
note the proximity of electrodes to any possible source of an
erroneous reading, such as a metal fence; the operator should
be aware when metal electrodes are not suitable and special
electrodes and/or salt water soaking of the ground is neces-
sary; repeat measurements should be made; lateral inhomo-
geneities need to be recognized in the field.
• Improper Interpretation—Most of the difficulty with this tech-
nique is associated with the interpretation. Often, the inter-
preter did not collect the field data and is not in a position to
recognize possible cultural interference in the data unless care-
ful field notes have been made. An accepted, verified inver-
sion program should be used to derive sections of true resis-
tivity versus true depth. Contour maps of apparent resistivity
can be highly misleading, and electrode spacing should not be
considered to have a linear relationship with depth of penetra-
tion.
A few of these pitfalls are cited in the following case histories.
Case History Site 1
Site 1 is the location of two unlined ponds containing an acid
fluid with chloride. Overburden forming the base and sides of the
ponds consists of low permeability silts and clays. Seven resistiv-
ity soundings using a Wenner array were conducted at several
locations, and an optimum "A" spacing of 35 ft was selected as
the basis for several fixed-spacing measurements. The apparent
resistivity at the 35-ft "A" spacing was contoured as shown on
Fig.l. On this basis, it was concluded that groundwater flow in
the overburden occurred predominantly in one or more thin dis-
crete sand units interbedded with the silt and clay. Chloride-
contaminated groundwater was interpreted to leak radially from
the pits and preferentially toward the northwest. A second source
of contamination was identified approximately 500 ft north of the
ponds. Bedrock was interpreted to be present at a depth of 25 to
45 ft with a N-NW dip, occasionally with a 10-ft layer of
weathered rock at the bedrock surface.
Comments: The soundings were not interpreted; i.e., true re-
sistivity versus depth sections were not calculated. Apparent re-
sistivity values were miscalculated so that the contoured values
should actually range between about 300 and 900 ohm-ft. This
range did not justify the fine contour interval presented. The
apparent resistivity values at all "A" spacings (from 5 to 80 ft)
generally do not exceed this range of resistivities. Information on
the depth to bedrock or bedrock weathering cannot be resolved
by the sounding curves. It is not known by what basis a 35-ft
"A" spacing was selected for fixed-spacing measurements, but
with the clayey soils found at this site it is certain that the 35-ft
"A" spacing docs not represent information from a depth of 35
ft. The available data are difficult to interpret, but the variation!
in measured values of apparent resistivity are consistent with in-
terbedded silt and clay with some sand lenses. The interpreta-
tion of a northwest migrating contaminant plume and the dipping
bedrock surface is not substantiated by the resistivity data. Pit-
falls: improper field procedures, poor interpretation and inade-
quate data base.
LEGEND
. WPARENT RESBTlvrrt FOR *
-125- FIXED OtPTM Of 36 FEET (IN
OHM -FEET)
Figure 1
DC Resistivity Results for Site I
Case History Site 2
To provide preliminary data on geologic conditions at a haz-
ardous waste landfill, a resistivity survey was conducted to pro-
vide guidance to the proposed drilling program. Specifically, the
survey was designed to identify the extent of low-permeability
sediments beneath a known aquifer and to provide information
regarding the lower aquifer. A grid of vertical soundings was
conducted around the landfill using a Wenner array with "A"
spacings ranging from 10 to 120 ft. The "Keck" method was
used to interpret the data. Contours representing resistivities at
228 CONTAMINATED AQUIFER CONTROLS
-------
4
6 7
* *
20-
60-
80-
100-
LANOFILL AREA
DATA PROBABLY
INVALID
Sj49 "'••"•734 '/.;• •J092-;."' -681 '1396
491
LEGEND =
F||<2SO OHM-FT (POSSIBLE CLAY)
f>:;] 250-500 OHM-FT (POSSIBLE FINE SAND)
&3>500 OHM-FT (POSSIBLE SAND AND CR4MEU
? SOUNDING LOCATION
.85
RESISTIVITY VALUE IN OHM-FT
DERIVED WITH KECK METHOD
Figure 2
Electrical Cross-Section Through Site 2
various depth intervals were generated, and geoelectric cross-
sections were made indicating zones of possible clay, fine sand
and sand and gravel. An example cross-section is provided on
Figure 2.
Comments: As shown in the cross section, the "Keck" method
generated some unrealistically high resistivities, some higher than
1,000,000 ohm-ft. Such points should have been recognized as
due to noise and eliminated. The interpreted cross-section de-
rived is not geologically realistic and implies that the "A" spac-
ing is somehow equivalent to depth, which it is not. A more real-
istic and meaningful cross-section probably could have been ob-
tained by use of a conventional inversion technique. However,
the use of a resistivity survey to derive information from a hori-
zon beneath a known aquifer implies the existence of more layers
than the resistivity technique can be expected to interpret. Pit-
falls: poor interpretation and improper use of technique.
Case History Site 3
To map the migration of a contaminant plume from a haz-
ardous waste landfill, a series of geoelectrical soundings was
conducted at the perimeter of the site. A detailed stratigraphic
model of numerous layers was defined. The raw sounding data
are plotted on Fig. 3.
Comments: The soundings at all locations were essentially iden-
tical. Geologic conditions were either very uniform and homo-
geneous or for some other reason resistivity contrasts just did not
exist. Pitfalls: adverse geology.
Electromagnetics (EM)
EM surveys are similar to DC resistivity surveys because they
also measure the electrical properties of the subsurface. With this
1000
900
g no
I
_.ZBil57 T
o
» 60 100 500 1000
L-SEPARATION (FEET)
Figure 3
Summary of Geoelectric Soundings from Site 3
technique, it is not necessary to plant electrodes in the ground
and measurements are, therefore, quicker and easier to perform
than with DC resistivity. Areas with a highly resistive surficial
soil, asphalt or concrete which preclude the planting of elec-
trodes, are readily surveyed with EM equipment. EM measure-
ments are not as susceptible as DC resistivity to the presence of
metallic interference such as fences, underground pipes or scat-
tered metallic debris. With these advantages, many investigators
apparently feel that EM methods can replace the need for DC
resistivity. However, site conditions favorable to DC resistivity
can severely limit the effectiveness of EM and there are other
pitfalls, as outlined:
• EM measurements are highly susceptible to cultural or natural
EM fields. Power lines, underground cables, transformers,
etc., which tend to be present at hazardous waste sites, can
severely distort the measurements. Field personnel must care-
fully document the position of known EM interference.
• EM surveys do not work well where the resistivity of surficial
materials is low, for example where chemicals have been spilled
on the surface or where clay soils are present.
• The EM method has very limited capability for defining the
variation of resistivity with depth.
The above restrictions are severe. In cases where the desired
result is to map a contaminated plume in a sand layer beneath a
surficial clayey soil in an area of cultural interference, it prob-
ably is not worth the effort to conduct the survey. Note that many
hazardous waste sites fit this description.
Case History Site 4
An EM survey was conducted to define the extent of soil and
groundwater contamination around a sludge lagoon. Measure-
ments were taken in essentially a random manner with a Geonics
EM-31 (Fig. 4). The study concluded that the survey was not suc-
cessful in defining the extent of contamination because insuffic-
ient contrast existed between contaminated and non-contami-
nated areas.
Comments: The results shown on Fig. 4 clearly show the pres-
ence of anomalously high ground conductivity along the south-
ern border of the lagoon which gradually decreases with distance
away from the lagoon (see contours added on Fig. 4). This should
have been identified as a contaminant plume, as was later demon-
strated on the basis of groundwater testing. The study would
have benefited greatly if systematic measurements were taken
along profiles or as a grid, rather than in a haphazard manner.
CONTAMINATED AQUIFER CONTROLS 229
-------
Magnetics
A modern magnetometer, such as a proton procession device,
is a powerful, cost-effective tool for delineating regions which
contain buried ferromagnetic material, especially buried drums.
However, the use of magnetic surveys often can fall short of the
expected goal of accurately defining the region of burial. The
following pitfalls frequently cause problems:
• Inadequate Survey Layout—The most effective survey lines
should be oriented N-S, although in some cases this may not be
practical. Readings should be taken at a minimum of every 10
ft along the profile. Initially, profile lines can be separated by
about 30 ft, with additional lines added if anomalies are en-
countered.
• Cultural Interference—One cannot find buried drums when the
surface is covered with scrap iron. Careful notes should be
made by the field technician of the presence of any ferromag-
netic material, such as "tin" cans, construction debris, build-
ings, fences, etc.
• Misinterpretation of Anomaly Patterns—Buried ferromag-
netic material can produce a complex magnetic signature which
frequently is subject to misinterpretation. In particular, with
the orientation of the earth's magnetic field in North America,
a buried drum will cause a magnetic high on the southern edge of
the surface projection of a buried drum and a magnetic low to
the north of it. Caution should be exercised when using com-
plex deconvolution techniques to estimate the mass and depth
of buried metal, although in some cases meaningful calcula-
tions can be made.
In addition to using a conventional magnetometer, a gradio-
meter (essentially two magnetometers in one, where the differ-
ence in response of two sensors at different elevations is re-
corded) is also commonly used. This system frequently is more
efficient in determining whether or not buried ferromagnetic ma-
terial is present, but it is subject to the same limitations as a con-
ventional magnetometer and anomaly patterns are more difficult
to interpret.
Case History Site 5
Site 5 was suspected of containing buried waste in drums, and
a total field magnetic survey was conducted on a 10-ft grid to
LEGEND
SO WOUND CONDUCTIVITY
IN UUHO/U UiOC WITH
EM-31
,US POSSIBLE CONTOURS OF
OHOUND CONDUCTIVITY
INTERPRETED BY AUTHORS
Figure 4
Results of EM Survey at Site 4
230 CONTAMINATED AQUIFER CONTROLS
locate this material. Data were contoured and interpreted to de-
fine three pit locations and a trench (Fig. 5).
Comments: Several mistakes were made in the interpretation.
The linear anomaly trending E-W in the southern part of the site
proved to be essentially surficial scrap metal which should have
been noted in the field by the technician. The interpreter should
have suspected the anomaly was surficial because of the absence
of a pronounced magnetic low north of this anomaly. The sharp
anomaly in the northwest corner proved to be an abandoned well
casing that should have been noted by the field technician. The
anomaly in the northeast corner did prove to be related to haz-
ardous waste, but two pits were interpreted, whereas the anomaly
pattern is indicative of only one source. Pitfalls: improper field
procedures (inadequate note-keeping) and improper interpreta-
tion.
Ground Probing Radar (GPR)
The GPR technique has developed almost exclusively as a tool
of engineering geophysics and as such is not generally familiar to
most geophysicists with a background in the petroleum or mining
industries. It is capable of generating in real-time, shallow earth
profiles of dielectrical discontinuities related to subsurface con-
ditions such as moisture content, lithology, bedding, voids, frac-
tures, as well as man-made objects. When conditions are favor-
able, GPR profiles exhibit the greatest detail and resolution of
any technique. However, conditions are seldom favorable and the
pitfalls of measurement and interpretation are numerous, as out-
lined.
• Adverse Soil Conditions—Radar waves will not effectively
penetrate damp, low-resistivity clay or other conductive ma-
terial.
• Improper Antenna—The selection of the proper antenna is
difficult to predict in advance, except in general terms. It is
preferable to be prepared to try several frequencies between
about 100 and 600 MHz before selecting the optimum fre-
quency.
ROM)
LEGEND
•500-
MAGNET1C INTENSITY (TOTAL FCLD AFTER
REMOVING NATURAL FCLO)
•TTERPRETED PIT LOCATION
INTERPRETED TRENCH LOCATION
Figure 3
Interpreted Magnetic Map of Site 5
-------
i Adverse Surface Conditions—In many cases, long grass is suf-
ficiently conductive to present a problem of penetration.
Rough ground can cause patterns to appear on the record
when the antenna is bounced. These patterns can be confused
with subsurface signals. Extreme care must be taken to assure
that the movement of the antenna is smooth, and substantial
surface grooming may be required.
• Cultural Interference—Small pieces of scrap metal on the sur-
face can severely distort a GPR record, as can any buried metal
object. An unshielded antenna can be affected by a nearby
EM source, such as a power line. Rebar in an otherwise fav-
orable concrete surface will severely distort a record.
• Improper Calibration—Unless a target at a known depth can
be identified, depth is difficult to derive from a single antenna/
receiver. Where the antenna and receivers are separate, depth
can be calculated following principles similar to the normal
moveout correction employed by seismic reflection specialists.
• Improper Interpretation—Generally speaking, interpretation
requires the intervention of an expert. The GPR method fre-
quently records patterns that defy interpretation and much
additional data frequently are required to make sense of the
results.
No case histories of the GPR technique are provided. It is
assumed that anyone who has familiarity with the method (un-
less that person's experience is with sand dunes, permafrost or
ice) will be aware of case histories where the method did not
work.
Seismic Refraction
The seismic refraction technique has long been a mainstay of
the engineering geophysical profession, as it offers good potential
for determining depth to bedrock, rock strength, depth to satur-
ated soil or rock and rock and soil layering in general. Some of
the limitations of the method are well known, especially that it
will not identify any layer which has a lower seismic velocity than
the layer above it. Fortunately for this method, ground conditions
in natural terrain usually are favorable for conducting a good
survey. Conditions at hazardous waste sites frequently are not as
favorable, and special precautions must be taken. Typical prob-
lems are outlined below:
• Low-Velocity and/or Variable-Velocity Surficial Layer—Fill
material commonly found at hazardous waste sites must be
evaluated with extreme caution. Geophones must be closely
spaced near the source to accurately measure the first layer
velocity and identify any lateral velocity variations. Failure to
do this can cause gross errors in determining the depth to deep-
er horizons. This implies that a survey at a hazardous waste site
should utilize substantially more shot locations than a conven-
tional survey.
• Data Quality—Industrial sites are frequently noisy, and it may
be necessary to utilize sources of energy more powerful than
normally would be used for a given spread length. The equip-
ment should be capable of signal stacking to reduce noise. The
field technician must be responsible for assuring that the first
arrival waveforms are clearly and consistently defined.
• Interpretation—Simplified interpretations that can be based
on hand calculations are not adequate for hazardous waste
work, where the contacts between individual layers are fre-
quently irregular. A number of acceptable processing/inver-
sion programs which account for irregular layering are pub-
licly available. It is important for the interpreter to have access
to site geological data, preferably from borings, to obtain
meaningful results.
The case history cites an example where good data were ob-
tained, but simplified interpretation led to substantial misinter-
pretation of the geological setting.
Case History Site 6
This site was the locality of extensive PCB spills over a num-
ber of years. Off-site migration in aquifers bounded by bed-
rock channels was considered possible, and a seismic refraction
survey was conducted along the borders of the site. Hand calcu-
lations used to interpret the seismic refraction data did not indi-
cate the presence of a bedrock channel (Fig. 6).
Comments: The hand calculations to derive depth to bedrock
were complicated by the presence of three layers above the bed-
rock. Computerized inversion of the data with the Generalized
Reciprocal Method defined the presence of a bedrock channel.
The overall seismically-derived stratigraphy subsequently was
confirmed by borings.
CONCLUSIONS
Much of the difficulty with the application of geophysical
technology to problems of groundwater contamination and haz-
ardous waste lies in the inexperience of the individuals conduct-
ing the surveys. Much of the work is conducted by hydrogeolo-
gists and civil engineers who do not have a strong background in
geophysics. Conversely, the majority of geophysicists have their
main expertise related to petroleum exploration and cannot be
expected to be familiar with the specialized geophysical studies
required for groundwater and hazardous waste studies. In some
cases, a contracting or consulting firm may achieve competency
with one specific method and tend to always employ that method,
even if others would be better suited. The overall problem is well
stated by Kendrick Taylor of the Desert Research Institute, Reno,
Nevada, in a recent letter to Dr. Stanley Ward published in the
February 1986 issue of Geophysics: The Leading Edge:
"Inaccurate information from both government and over-
zealous contractors and equipment manufacturers along
with instant geowizards with no real background have on
occasion raised expectations [of geophysics] to unobtain-
able levels that result in inevitable disappointments. At
several recent conferences it was clear that the geophysi-
cists could do the work but frequently had a difficult time
relating it to hydrogeology and that hydrogeologists who
were inquisitive enough to use geophysics, frequently did
not use the methods in the most advantageous way.
Hence, we see a situation with much confusion which in
the long run discourages the use of geophysics.''
UNSATURATED ALLUVIUM
GLACIAL TILL
LKNTIM-FCET -ID1
MOTE: PARABOLIC TRACE GENERATED BY COMPUTER PROGRAM BASED
ON GENERALIZED RECIPROCAL METHOD; SOLID LINES BASED ON
SIMPLIFIED HAND CALCULATIONS.
Figure 6
Cross-Section of Site 6 Based on Seismic Refraction
CONTAMINATED AQUIFER CONTROLS 231
-------
In spite of the difficulties which have occurred in the applica-
tion of geophysical technology to investigations at hazardous
waste sites, many excellent surveys have been conducted. When
properly applied by experienced personnel, geophysics is a pow-
erful tool. With a minimum amount of site information, prefer-
ably with a site visit, the geophysicist usually can assess the prob-
ability of success of a given technique and define an effective
program of study. Some locations are so adverse that geophysi-
cal techniques are not appropriate, but such locations can be de-
fined in advance.
REFERENCES
1. Pennington, D., "Selection of Proper Surface Resistivity Techniques
and Equipment for Evaluation of Groundwater Contamination,"
NWWA Conference on Surface and Borehole Geophysical Methods
in Groundwater Investigation*. Fort Worth, TX, 1985.
2. Benson, R.C., Glaccum, R.A. and Noel, M.R., "Geophysical Tech-
niques for Sensing Buried Wastes and Waste Migration," Environ-
mental Monitoring System* Laboratory, Office of Research and
Development, U.S. EPA, 1982.
3. Nielsen, D.M. and Curl, M., Ed*., Proc. NWWA/EPA Confer-
ence on Surface and Borehole Geophysical Methods in Ground-
water Investigations, San Antonio, TX, 1984.
4. National Water Well Association, Proc. NWWA Conference on Sur-
face and Borehole Geophysical Methods in Groundwater Investiga-
tions, Fori Worth. TX. 1985.
232 CONTAMINATED AQUIFER CONTROLS
-------
Quality Assurance Testing of
Monitoring Well Integrity
Janetta X. Knox
Peter R. Jacobson
Woodward-Clyde Consultants
Plymouth Meeting, Pennsylvania
ABSTRACT
The loss of monitoring well integrity may prevent the acqui-
sition of reliable and representative results during groundwater
quality investigations. Aside from faulty design and installation,
loss of monitoring well integrity is the absence of casing or grout
leaks either into the well or between aquifers. This definition is
adapted from the concept of mechanical integrity in the U.S.
EPA's Underground Injection Control Program. Loss of moni-
toring well integrity can result in inaccurate water level measure-
ments, nonrepresentative water samples and cross-contamination
of aquifers.
Potential methods of testing monitoring well integrity include
well records inspection, cement bond logging, temperature log-
ging, density logging, neutron logging, television logging, bore-
hole televiewer, noise logging, tracer logging, caliper logging,
pressure testing, pipe analysis survey and electromagnetic thick-
ness survey. Most of these methods were developed for testing
use in petroleum, mining or injection wells, which are generally
deeper, wider and constructed and operated differently from con-
ventional monitoring wells. Furthermore, these methods may lack
the sensitivity to detect the types of leaks manifested by the micro-
annuli of a failing monitoring well.
Most logging techniques are limited in applicability due to the
small diameter and shallow depth of monitoring wells. Cement
bond logs may produce the most reliable results to detect the in-
tegrity of a casing-cement-formation bond. However, casing leaks
must be detected by other techniques such as television or caliper
logs. Inspection of well records may be a successful means of
qualitatively describing the viability of monitoring wells at in-
stallation, depending on the completeness of the well records.
Comparisons of theoretical and actual grout usage may be used
to imply good or poor grout emplacement. Where grout quality
is suspect, compatibility tests with formation fluids should be
performed to determine the ability of the grout to withstand
chemical attack, especially where the aquifer is known to contain
fluids that could aggressively attack the grout. Grout compatibil-
ity investigations should be part of monitoring system design.
INTRODUCTION
Once installed, the integrity of most monitoring wells is rarely
questioned. As an integral part of groundwater quality investiga-
tions, monitoring wells are designed for the particular conditions
to which the well and its grout, sand pack, seals, etc., will be
subjected. Under ideal conditions, the well is installed by a com-
petent driller under the supervision of a qualified geologist/
hydrogeologist/engineer who has the project perspective on the
well's long-term purpose. Water quality investigations may ex-
tend over many years, and monitoring wells are expected to last
with the study. Often, wells are needlessly replaced due to im-
proper design or poor initial emplacement.
Inherent in this system is the potential for well failure. Well de-
fects may occur as a result of improper design (e.g., incompat-
ible materials or incorrect placement of seals), faulty installation
(improper or sloppy methods), physical abuse from equipment or
sitting idle between sampling episodes. With multistage ground-
water studies and remediation projects, the wells' lifespans may
extend over many years in contact with corrosive fluid. Defects
may be severe, placing the validity of samples collected from the
wells in question. Nonrepresentative samples may be obtained
from wells which outwardly appear to be reliable.
Since even minute leakage into or out of the well could signif-
icantly affect the parts-per-billion analytical results obtained from
analyses of groundwater from the well, such leakage must be de-
tected. However, small leaks are difficult, if not impossible, to de-
tect, especially in small-diameter monitoring wells.
This paper discusses the applicable methods of testing the integ-
rity of monitoring wells and presents some ideas for identifying
potential integrity problems during groundwater quality investi-
gations. For complete descriptions of the available well logging
methods, see Hearst and Nelson,1 Nielsen and Aller,2 Keys and
MacCary3 and Kwader.4
TYPES OF WELL INTEGRITY PROBLEMS
Section 146.08 of the U.S. EPA's Underground Injection Con-
trol (UIC) Program (40 CFR Part 146) concerns the mechanical
integrity of injection wells. According to these rules, an injection
well has mechanical integrity if: (1) there is not significant leakage
in the casing, tubing or packer, and (2) there is not significant
fluid movement into an underground source of drinking water
through vertical channels adjacent to the well.
The rules state that some combination of listed tests shall be
used to evaluate the absence of significant leaks. The section also
describes methods to demonstrate the absence of fluid move-
ment, including: (1) well records demonstrating the presence of
adequate cement to prevent such migration or (2) the results of a
cement bond log, sonic log, temperature log, density log or neu-
tron log. The following describes the applicability of these meth-
ods to monitoring wells. Additional methods not listed in the UIC
regulations to test monitoring well casing and cement grout in-
tegrity are discussed in this paper. These well logging methods
have not been widely incorporated into groundwater quality in-
vestigations, but may be helpful in assessing monitoring well in-
tegrity.
The UIC Program regulates wells used for subsurface injection
of fluids such as industrial waste or oil field brines. It recognizes
casing, tubing or packer leaks as the primary means of an injec-
CONTAMINATED AQUIFER CONTROLS 233
-------
tiorvwell's loss of integrity. Monitoring wells are constructed dif-
ferently from injection wells and have no open annulus, tubing or
packer (Fig. 1). For monitoring wells, loss of integrity can be de-
fined in terms of the four generalized types of problems shown in
Table 1. Although any of the four types of problems described in
Table 1 can affect the quality of samples obtained, this paper
will address only potential means of detecting casing and grout
leaks. Improperly placed gravel packs, seals and grouts may be
significant factors in determining well integrity, but these prob-
lems are avoided by careful well design and installation.
MECHANICAL INTEGRITY TESTS
Well Records
The well records obtained during drilling usually contain in-
formation on types, sizes and lengths of casing and the types,
quantities, weights of cement-based grout and methods of em-
placement. These records probably do not indicate if the cement
was successfully emplaced and an effective seal was obtained.
However, an implication of good or poor grout emplacement
may be possible by comparing estimates of theoretical grout re-
quirements (based on annulus volume) with the actual volume of
grout used. A severe discrepancy in volume used may indicate
that the grout bridged the annulus during emplacement, leaving
a section of annulus unsealed.
Cement Bond Logging
Cement bond logs can help evaluate the condition of grout be-
hind the casing. These logs indicate the potential for fluid move-
ment by monitoring the quality of the bond between the casing
and the grout and between the grout and the formation. The
logging method relies on the difference between the energy loss of
a sound pulse traveling through casing that is free-standing in the
hole and the energy loss of a pulse traveling through casing that
is firmly bonded to a hard material of a low sonic velocity, such
as cement grout.
The cement bond log, which is a type of sonic log, indicates
whether the cement is bonded to the casing and to the forma-
tion. However, it should be pointed out that this only indicates
the presence or absence of an adequate bond. In rock where there
are known vertical and horizontal fractures, these also would be
detected as poor bonding. The cement bond does not detect fluid
migration behind the casing; it indicates whether such a poten-
tial exists.
Temperature Logging
Three types of temperature logs currently are available: con-
ventional, differential and radial differential. The temperature of
the earth increases with respect to depth except for approximately
the first 100 ft, which are influenced by partial fluid saturation
and seasonal variations in temperature. Below this depth, the
temperature gradually increases at a rate of approximately 1 °F
per 100 ft. Conventional and differential temperature logs record
minute changes in temperature as a function of depth. The differ-
ential temperature log more sensitively measures the geothermal
gradient, detecting slight changes in well temperature. The radial
differential temperature log measures the variations in tempera-
ture in the plane of the casing radius at two points. It can locate
channeling behind the casing by detecting minute temperature
anomalies.
Temperature logging methods are most advantageous in wells
deeper than 100 ft. Their application to monitoring wells should
be considered where there is a temperature differential between
the aquifers penetrated by the well.
Density Logging
The density or gamma-gamma log is primarily a tool for meas-
uring porosity by measuring the electron density of a material. It
measures the intensity of backscattered gamma radiation emitted
by the density log probe. The results of the log indicate the pres-
ence of grout within 6 in. of the casing center, but may not pro-
vide detailed information on the adequacy of the grout. Density
logging should be considered when gaps in the grout are sus-
pected.
Neutron Logging
The neutron log operates by emitting and receiving neutrons.
Cement grout contains more interstitial water than surrounding
rock formations and less than groundwater. The neutron log thus
can distinguish between grout, rock and groundwater by different
degrees of neutron attenuation. The method may give some indi-
cation about the presence or absence of grout. However, hydro-
carbons found in many groundwater studies may give anomalous
results in neutron logging.
Television (Visual) Logging
Television borehole logging has been used to visually inspect
casings by providing a continuous videographic log of the inside
well casing surface. This simple technique has some clear disad-
vantages. The minimum well diameter is 3 in. If the casing is cor-
roded or dirty, the camera will not detect holes or cracks in the
casing. Small cracks or holes are difficult to detect. Visual logging
may detect larger pits in the casing which are not channels for
fluid movement. Therefore, this test is not sensitive enough to
distinguish channels for small leaks but is recommended where
large holes or structural failures have occurred.
Borehole Televiewer
With high-frequency acoustic energy, the borehole televiewer
scans and provides an image of the inside casing surface. Casing
defects are visible on the resulting log to an experienced log ana-
lyst. The televiewer is available in smaller sizes than the visual
television logging device and can log through most homogen-
eous liquids. Disadvantages include limited experience in cased
wells and limited commercial availability of the equipment.
Noise (Acoustic Emissions) Logging
Fluid flowing through restrictions as leaks in the well casing or
channels behind the casing generate distinctive sound frequen-
cies. A sophisticated microphone traveling up the well can detect
and pinpoint the sound, provided the leak and the pressure
changes are of adequate magnitude. Noise logging is ideal for in-
jection wells which are under pressure, as fluid leaking from the
well would undergo a significant pressure drop and could spurt,
emitting a specific sound. Noise logging may not be helpful in de-
tecting leaks in monitoring wells with insufficient pressure differ-
entials between the aquifers penetrated by the wells. The tech-
nique, however, may be appropriate given adequate research and
development into the instrumentation sensitivities, reliability, re-
producibility and data interpretation.
Radioactive Tracer Logging
Radioactive tracers have been used by mixing the tracers with
well fluid and with cement before group emplacement. Tracers
in well fluid may be pressurized in the casing with a packer at the
bottom. If a casing leak is present, the tracer may enter the annu-
lus or formation and be detected after flushing the casing. Due
to the sensitive nature of monitoring well uses for groundwater
assessments, radioactive tracers are not highly recommended.
Callper Logging
Mechanical calipers contact and measure the inside casing sur-
face with a range of sensitivity (2 to 64 feelers), producing a pro-
file of the inside diameter with depth. Caliper logging is a simple
method of inspecting casing by detecting and signaling irregulan-
234 CONTAMINATED AQUII ER CONTROLS
-------
ties on the inner surface of the casing. One disadvantage is that
holes smaller than approximately 0.5 in. in diameter and vertical
cracks may go undetected by the calipers as they are raised along
the well. Caliper logging may detect casing pits which are not in
danger of becoming channels for fluid movement and may help
evaluate the quality of grout seals at the bottom of casings in wells
with open hole completion. Caliper logging is useful in detecting
variations in casing diameter due to chemical destruction of the
casing.
Pressure Testing
Pressure testing can locate casing leaks in a monitoring well by
using two packers in staged pressure tests. An isolated casing in-
terval may be pressurized using a fluid such as water while moni-
toring the pressure drop. Pressure tests can detect sizable casing
leaks, but do not detect grout leaks. An incomplete packer seal
may be confused with a casing leak. However, results of pressure
tests may contribute to the assessment of monitoring well in-
tegrity.
Pipe Analysis Survey
The pipe analysis survey was developed to detect downhole
corrosion damage such as holes, gouges or cracks by measuring
fluctuations in an induced magnetic field. Using high-frequency
eddy current and magnetic flux leakage tests, defects on the inner
surface and the outer surface of the casing wall can be dis-
tinguished by a skilled log analyst. The survey can detect dam-
age as small as 0.125 in. on the inner casing wall and 0.375 in. on
the outer casing wall. Although the pipe analysis survey is one of
the best available methods for detecting casing defects, it does not
provide information about fluid movement and can be run only in
steel-cased wells.
Electromagnetic Thickness Survey
The electromagnetic thickness survey measures the phase shift
of an induced magnetic field and detects casing deterioration,
including large-scale corrosion, casing splits and mechanical
wear. However, the log is dependent on the magnetic and elec-
trical properties of the casing being surveyed. It is difficult to dis-
cern whether a log anomaly is due to loss of metal from the casing
or a change in casing properties. The logging method is limited to
metal casing wells with outside diameters between 4.5 and 9.625
in. The resolution also is limited to pits or holes at least 1 in. in
diameter.
DISCUSSION
None of the test methods described above can verify conclus-
ively the absence of casing or grout leaks in monitoring wells,
although some methods provide a higher degree of confidence
than others. Monitoring well integrity testing is most conclusive
with the detection of leaks or poor grout seals. Tests interpreted
to indicate the absence of leaks may only reflect an improper or
insensitive test, regardless of the well's integrity.
The best way to increase the level of confidence of a testing
program is to incorporate several test methods into the program.
For logging techniques, this generally is quite feasible, as most
well logging service companies can provide several of the recom-
mended methods. Also, the most logistically cost-effective ap-
proach usually is to conduct a testing program in stages, initial-
ly inspecting well records, followed by a limited logging program
to test the applicability of selected methods to individual wells.
The limited logging may be followed by more comprehensive log-
ging, testing additional wells at the site. Following analysis of
the logs, pressure tests may be used selectively on individual wells
for which the logs are inconclusive or indicate a high probability
of leakage.
The selection of a particular test method may depend on the
type and scale of the integrity problem experienced by the well in
question; however, any symptoms exhibited by the well may be
subtle and may not provide sufficient insight into the nature of
the problem. For example, if large-scale casing leaks are sus-
pected, caliper logs would be appropriate, possibly supplemented
by borehole television. For suspected grout problems, cement
bond logging is the most widely recommended method and may
be accompanied by density logs.
Site-specific factors need to be considered in the design of any
testing program. Well construction details will dictate the applic-
ability of techniques such as pressure testing, pipe analysis sur-
vey and borehole television. Well depths and hydraulic grad-
ients between aquifers are important in determining the viability
of temperature logging and noise logging, respectively.
The costs of performing a logging program generally can be
separated into three main elements: (1) rental and mobilization
costs for the logging equipment (usually truck-mounted), (2) per-
sonnel costs to operate the equipment on the site and (3) inter-
pretation costs by an experienced well log analyst. For a given
program, these three elements represent approximately equal por-
tions of the total cost.
All three of the cost elements are scale-dependent; the more
wells tested or the deeper the wells, the lower the per-foot or
per-well costs. Increasing the number of well logs will increase the
project costs, but not always in direct proportion to the number
of logs. Interpretation time is an important factor in total costs;
however, the level of effort required is dependent on the com-
plexity of the logs, the number of logs, the ability to cross-corre-
late the logs and,the subtlety of the integrity problems.
GROUT COMPATIBILITY
The question of monitoring well integrity may be partly ans-
wered by assessing the grout's compatibility with its environment.
The assessment may be conducted both by library and by labor-
atory, both before and after well emplacement.
Studies of grout durability in the presence of hazardous wastes
and leachates have been conducted for construction, slurry wall
and waste isolation projects; the information has been collated
by publications such as Spooner et al.3 Although the informa-
tion is far from complete, it may contribute to choosing the most
durable grout for a given environment. Spooner, et. al., have pro-
duced matrices of known and predicted effects of different chem-
ical groups on the set time and durability of various grout types.
From this and additional information, an appropriate grout may
be chosen for specific areas of a contaminated site.
Little information is available about the combined effects of
different chemical groups on a grout. One can perform labor-
atory tests in combination with library search information to
establish the compatibility of a specific hazardous waste with the
grout. Fixed-wall and triaxial permeameters can be used to meas-
ure the effects of chemicals on permeability. Visual observation,
although subjective, is one of the easiest methods for recording
set time changes due to chemical interactions.
CONCLUSIONS
Logistically, the currently available tests to detect leaks in the
casing or fluid movement are not always applicable to monitoring
wells. These tests were developed for oil, mining or disposal in-
dustry wells which are deeper, wider and under pressure. Further,
injection wells which are pressurized regularly are more likely to
crack or wear the casing and cement grout. No single well log-
ging method stands out as the solution to monitoring well integ-
rity problems. The scale of sensitivity needed for leak testing in
CONTAMINATED AQUIFER CONTROLS 235
-------
Table 1
Types of Monitoring Well Integrity Problems
TYPE OP PROBLEM
CuInfUikl
Improper Or*v«l
Improper Sul/Grout
POSSIBLE CA08BS)
Mochutetl cull* dtn>f«4 bofora,
during, or .fur UuUlkUcni
miUrUI ch.mte.l Incompitblllly
Poor frout bonding) froul/ftqulfer
ImompublUty, (roul eraoklnf
from ntchankal dbrupUon)
Improper grout mixture.
Poor mil oMfni iloppy ml
IniUlliUon
Poor dulfn. ftalty ln.UU.tlon
POTEKnAL EFFECT
iMceurate w.ur ItvtU,
eroi»«onumlfuUon of
••rnplu ud •oulfirbj
««ur tavcti,
eroi»Uon of
I
F~
— an-t HIM emu
tllMM'MI
!*• 011»
fMH HMi «
t-«.
H""
11* noi««
monitoring wells exceeds the needs of most larger wells. A small
crack or hole spreading a few parts per million of contaminants
to another zone generally is not detectable by the methods de-
signed for injection wells. A combination of present logging
methods supplemented by pressure testing may be used to inter-
pret monitoring well integrity. Casing integrity and grout integ-
rity may be established best by noise or cement bond logging
methods. All test methods require interpretation by qualified
analysts to maintain reasonable confidence levels.
Assessing the durability and compatibility of monitoring well
grout may also provide clues to the problem of well integrity.
Laboratory tests of grout durability may support confidence in
the present monitoring well integrity. During planning stages, a
suitable grout can be chosen in consideration of the groundwater
chemistry of a hazardous waste site. The choice does not necessi-
tate expensive laboratory time; it can be made from literature
surveys.
Figure 1
Typical Injection and Monitoring Well Designs
REFERENCES
1. Meant, J.R. and Nelson, P.M., Well Logging for Physical Proper-
ties. MacOraw-HtU, New York, NY, 1985.
2. Nielsen, D.M. and Aller, L.. "Methods for Determining the Mechan-
ical Integrity of Class II Injection Wells," EPA-600/2-M-121,1984.
3. Keys, W.S. and MacCary, L.M., "Techniques of Water-Resources
Investigations of The USGS," Chapter El. Application of BortHok
Geophysics to Water Resources Investigations, 1983.
4. Kwader, T., "Interpretation of Borehole Geophysical Logs in Shallow
Carbonate Environments and Their Application to Groundwater Re-
sources Investigation," 1982.
5. Spooner, P.A., Hunt, G.E., Hodge, V.E. and Wagner. P.M., "Com-
patibility of Grouts with Hazardous Wastes," EPA-600/2-S4-OI5,
1984.
236 CONTAMINATED AQUIFER CONTROLS
-------
Leachate Characterization and Synthetic
Leachate Formulation for Liner Testing
Jennifer A. Bramlett
Science Applications International Corporation
McLean, Virginia
Edward W. Repa, Ph.D.
National Solid Wastes Management Association
Washington, D.C.
Charles I. Mashni
U.S. Environmental Protection Agency
Cincinnati, Ohio
ABSTRACT
A U.S. EPA-sponsored study was conducted to characterize
leachates from hazardous waste land disposal sites and to assess
the feasibility of formulating a multi-compound synthetic leach-
ate for liner testing. Leachate samples from 13 hazardous waste
disposal sites were analyzed for priority pollutant metals and
organic compounds, other organic compounds, total cyanide,
total organic carbon, chemical oxygen demand and various other
general parameters.
The analytical data were evaluated to characterize the occur-
rence frequency and concentrations of detected constituents in
the leachates. Conclusions were made regarding the feasibility of
formulating a synthetic leachate based on the study data. Recom-
mendations were made for approaches to representing constit-
uents in a leachate formulation and for followup analytical pro-
grams which would more comprehensively characterize leachates
and enlarge the organic constituent data base.
INTRODUCTION
The Hazardous Waste Engineering Research Laboratory-
Cincinnati (HWERL) of the U.S. EPA Land Pollution Control
Division is developing a data base containing information about
a variety of hazardous wastes and associated leachate compo-
sitions. The data base is required to assess the feasibility of form-
ulating multi-compound synthetic hazardous waste leachates for
testing containment liners under consideration for use in landfills
and other hazardous waste storage, treatment and disposal facil-
ities. Liner and chemical compatibility experiments generally have
involved testing only a single chemical compound or waste.
Therefore, any synergistic effects on liners that might be caused
by multi-compound hazardous waste leachates generated from
complex waste mixtures are relatively unknown.
The U.S. EPA sponsored a study in 1985 to gather data on the
composition of leachates generated by operating hazardous waste
disposal sites. An assessment was made regarding the feasibility
of formulating a synthetic leachate based on the study data. The
data can also be used by other researchers to predict the chemical
compositions of leachates generated by various hazardous wastes
and as a general reference on leachate composition.
This paper presents the study approach, selected results and
recommendations for both synthetic leachate formulation and
followup analytical programs. Another U.S. EPA-sponsored
study which incorporates some of these recommendations was in-
itiated in June of 1986. The results of this new study were not
available at the writing of this paper.
DESCRIPTION OF SITES SELECTED
FOR LEACHATE COLLECTION
The leachate samples characterized during this study were
collected from 13 professionally operated hazardous waste land-
fills. These sites were selected from a master list of 43 operating
landfills which accepted either only hazardous wastes or a com-
bination of municipal and hazardous wastes. Besides willingness
to participate, criteria for site inclusion in the study involved con-
sideration of the following:
• Existence of a leachate collection system and system accessibil-
ity for sample collection
Table 1
Overview of Thirteen Sites Selected for Leachate Sampling and Analysis
sit.
Slu Age
Number (ton)*
1 3
2 3
3 S
4 4
5 6
6 3.S
7 6
8 7
Waste Type Input'
Alkaline inorganics; liquids end solids;
40% drummed/80% bulk
Variety, specifics not available; •• bulk
solids
Wide variety; inorganic and organic: solids
onry. drummed and bulk
Wlda variety; organic concentrations
< 5%; solids only; 25% drummed/75%
butt
Wide variety; inorganic and organic;
mostly containerized soMs and Bqukts
Variety; mostly petrochemical and
etoctropleting wastes; aoHds only;
drummed and bulk
drummed liquids
68% wastewaur biological treatment
Geographic
Location
In the U.S.
Southern
Southern
Southern
Central
Western
Northmen,
Northeastern
Net
Precipitation
Range (Inches)
-Wto+5
+K> to +15
+5 to +10
-Wto+5
<. -10
«. -W
+510+10
+5 to +W
sludge, 18% phthalate/benzyl chloride
wastes; 16% lime grit; bulk aolMs onry
Variety; inorganic and organic; drummed
non-halogenatad solvents and orjy
reekjuea; bulk pigments
wastes, asbestos, fry ash; drummed and
bulk, no free liquids
Wide variety; organic and inorganic,
drummed and bulk
70% PCB-containIng materials, 29%
waatewater metment sludge, 1%
cyanides and corrosbee: 20%
drummed/80% bulk
Wlda variety; inorganic and organic; solids
only; drummed and bulk
-10 to +6
+5W+W
+6 to+10
*This information is only for the sampled portion of a site.
LEACHATE FATE & CONTROL 237
-------
• Period of site operation, i.e., for 5 yr or at least long enough to
generate leachate at a sufficient rate for sample collection and
at a quality representative of disposal wastes
• Available and reliable information regarding the types of
wastes disposed at the site
• Contribution to an overall site profile which illustrated waste
type, geographic and climatic diversity
One study objective was the generation of a data base repre-
senting a wide spectrum of existing leachate characteristics. The
sites finally selected for inclusion were located in various geo-
graphic sections of the United States, thereby representing to
some degree varying climatic conditions. The sites also varied in
the relative quantities, types and physical forms of the wastes ac-
cepted for disposal (e.g., containerized liquids versus bulk solids);
the landfill disposal operating practices (e.g., cover material and
frequency of cover application); and the period of site operation.
All of these factors plus others can interrelate and impact the gen-
eration rates and chemical characteristics of the respective leach-
ates. Table 1 provides an overview of the 13 sites finally selected
for leachate sampling and analysis.
LEACHATE SAMPLE COLLECTION
AND ANALYTICAL PARAMETERS
Collection of leachate samples from each of the 13 sites occur-
red between June 9 and 21 of 1985. Sample collection was con-
ducted as close as possible to the generation source to maximize
sample representativeness of actual leachate quality. However,
points of collection varied depending on system design and leach-
ate accessibility. Sample collection points included leachate
collection system sumps, bleeder valves, pipe discharges into
drainage channels, recently filled storage tanks and, in one case, a
storage lagoon.
Field tests (i.e., pH, temperature, redox potential and specific
conductance) were performed on-site. Laboratory analyses in-
cluded tests for volatile organics; semi-volatile organics, includ-
ing acid and base/neutral extractables; heavy metals; total cy-
anide; total organic carbon (TOC); and chemical oxygen demand
(COD).
Laboratory analyses involved standard U.S. EPA procedures
and protocols. Samples for the organic analyses had to be diluted
five or ten times to reduce their high chemical concentrations to
testable levels. A 24-hr continuous liquid/liquid solvent extrac-
tion system was used during the analyses of semi-volatile organ-
ics rather than the separation funnel technique in order to avoid
emulsion formation.
OVERVIEW OF THE ANALYTICAL RESULTS
The data generated from the analyses of the leachate samples
during this study are too extensive to present completely in this
paper on a sample-specific basis. However, general information
regarding the occurrence of the components and the ranges of
certain parameter levels will be presented. A report which pre-
sents the details and complete results of this study was submitted
to the U.S. EPA in September 1985 and will be made available to
the public.'
Field Tests and COD Data Results
Sample temperature, pH, redox potential and specific conduc-
tance were measured at the time of sample collection. Data for
these parameters, however, were not considered reliable for every
site because of suspected field instrument malfunction.
Leachate temperature was measured at 5 of the 13 sites and
ranged from 20 to 32 °C, with a mean of 27 °C and a standard
deviation of 6.2°C. The parameter of pH was measured at 5 sites
and ranged from 7.1 to 9.3, with a mean of 8.2 and a standard
deviation of 0.857. Redox potential was measured at only 3 sites
and was recorded as -0.343, -0.241 and -0.093.
Specific conductance was measured at 9 of the 13 sites. A spe-
cific conductance greater than 20,000 micromhos/cm was meas-
ured in samples from Sites 4, 6, 8 and 10. The specific conduc-
tance of samples from the other 5 sites ranged from 4,250 to
12,000 micromhos/cm.
Laboratory analysis for COD was performed on samples from
all of the sites. The results ranged from 1,950 to 23,300 mg/l,
with a mean of 10,217 ppm and a standard deviation of 6,475
mg/l. Samples from Sites 3, 4, 5, 6, 7 and 9 had COD measure-
ments of less than 10,000 mg/l.
Inorganic Data Results
Each of the 13 samples was analyzed for 13 metal priority
pollutants including silver, arsenic, beryllium, chromium, cad-
mium, copper, mercury, nickel, lead, antimony, selenium,
thallium and zinc. Most of the metals were detected in every
sample except mercury, antimony, thallium and beryllium. Gen-
erally, the metals were detected only in the low or fractional
mg/l. Beryllium was the least commonly detected metal and was
detected only in samples from six sites.
Arsenic and selenium were the most common of the metals de-
tected at least once at levels greater than 1 mg/l. They were de-
tected in samples from 7 sites each, followed by nickel and zinc
in 5 samples each and copper in 4 samples. The samples collected
from Sites 1, 3, 6 and 12 contained 5 or more metals at concen-
trations greater than 1 mg/l, including selenium and zinc in all
cases.
Total cyanide was detected in samples from 9 sites. Cyanide
levels ranged from 0.01 to 55 mg/l. Five of the leachate sam-
ples contained total cyanide at levels less than 1 mg/l. The high-
est levels of total cyanide were 27.6, 40 and 55 mg/l and were de-
tected in samples from Sites 11,1 and 3, respectively.
Total Organic Carbon Results
Total organic carbon (TOC) was determined to gauge how suc-
cessfully analysis had identified the organic constituents. The
constituents have been comprehensively identified if analytical
TOC equals the calculated TOC of the whole sample based on
measured combined quantities of individual organic compounds.
The analytical TOC values ranged from 195 to 11,750 mg/l.
The percentage of the analytical TOC accounted for was less than
10<% for 11 of the 13 leachate samples and less than 5% for 6 of
the 13 samples. A substantially larger percentage of the analytical
TOC was accounted for by the calculated TOC in samples from
Sites 5 and 9, 40.4 and 59.5Vo, respectively. These samples also
had the lowest analytical TOC values at 195 mg/l (Site 5) and
309 mg/l (Site 9).
The low percentage of analytical TOC accounted for reflects
substantial concentrations of non-volatile low or high molecular
weight organics or other constituents which do not extract or suc-
cessfully chromatograph using routine and standard analytical
methods. Three other possible explanations for the low accounta-
bility of TOC include:
• The incomplete extraction of water soluble semi-volatiles may
have occurred during sample preparation.
• A combination of sample concentration (very high in organics)
and sample complexity (a large number of diverse compounds)
may have caused misidentification of compounds. This is un-
likely because the mass spectrometric results were computer
matched. However, OC peak overlap was observed and, even
with the identification of peak components by mass spectro-
metry, concentration errors may have occurred.
• The OC/MS methodology was highly sensitive, and most of the
leachate samples contained a large organic component. There-
238 LEACHATE FATE & CONTROL
-------
fore, the samples required large dilutions to keep the readings
on scale. These dilutions increased the minimum detection lim-
its for the compounds, which ranged from as little as 25 >ig/l to
as much as 10,000 jig/1. As a result, many trace constituents
which may have been detectable in an undiluted sample were
rendered undetectable by the large dilutions.
Organic Data Results
The leachate samples were analyzed for 35 volatile and 68
semi-volatile organic priority pollutants. In addition to the de-
tected priority pollutants, 84 non-priority pollutant compounds
and families of compounds were identified by matching GC/MS
spectra with a library compiled from National Institute of Health
and U.S. EPA libraries.
All of the detected organic compounds were grouped into the
six general classes of organic compounds which are frequently
used to discuss the compatibility of chemicals with various con-
tainment liners. These classes include organic acids, oxygen-
ated/heteroatomic hydrocarbons, halogenated hydrocarbons,
organic bases, aromatic hydrocarbons and aliphatic hydrocar-
bons.
The overall-characterized TOC on average equalled approx-
imately 4% of the total sample analytical TOC. Assignment of
this characterized amount to the six classes mentioned above
(based on mole fraction) is as follows (in decreasing order):
organic acids, 39%; oxygenated/heteroatomic hydrocarbons,
35.8%; halogenated hydrocarbons, 11%; organic bases, 7.2%;
aromatic hydrocarbons, 6%; and aliphatic hydrocarbons, 0.9%.
In general, the classes containing compounds with relatively high
aqueous solubilities accounted for higher mean mole fraction
percentages than did the classes containing compounds with lower
aqueous solubilities.
A summary of the leachate organic compound occurrence data
is presented in Table 2. The following observations were made
based on all of the data:
• Organic acids, as a class, were approximately 55% (by mole
fraction) phenol and substituted phenols and 45% carboxylic
acids, including benzole acid and alkanoic acids with 4 or more
carbon atoms. The compounds detected in leachate samples
from the greatest number of the sites were phenol (13 sites),
4-methylphenol(12 sites), 2-methylphenol (10 sites), 2-4-di-
methlyphenol (9 sites) and benzoic acid (8 sites).
Table 2
Summary of Leachate Organic Chemical Occurrence Data
Chemical Diminution
Percent Occurrence
(Toul Mean
Hepreaentetlve ChemlceMel and
Occurrence (Total Meen Mole Fraction)
Organic Adda
Oxygenated/ Heteroatomlc
Helogenited Hydrocarbon
Organic Baaee
Ammitic Hydrocarbon
*%*a«c Hydrocarbon
7.2*
8.0*
0.9%
Phenol 111.8*1
Subatttuted Phenote 117 compounda at 9.5*1
Benzole Add 15.3*1 end Subatrtuted Benioic
Adda 14 compounda at 0.1*1
AJkenofc Adda (13 compounda at 12.3*1
Acetone IM.5«)
Common Ketone SoKenta, e«.. 2-Hexanone,
2-Butanone, and e-MethyU-pontanone 19.2*1
AJcohob of el lypaa IM compounda at 8.1*1
Mettiytjno Chloride 18.8*1
CMorobenianea (4 compounda at 1.4*1
MuMehtorinaud Atonee/AJkenea 110 eompounda
at 2.8*1
AnBne 12.9*1 and Subettutad Anaaiee
(8 compounda at 1.4*1
Ibluenee (4.2*1
Benane and Akyta
Ibluenee) 11.4*1
TNe group old not have any good ianeaeiiml»«a
• The oxygenated/heteroatomic hydrocarbons, as a class, were
approximately 46% acetone, 26% common ketone solvents
and 23% alcohols. The compounds detected in samples from
the greatest number of sites were acetone (13 sites), 2-hexa-
none (13 sites), 2-butanone (12 sites), 4-methyl-2-pentanone
(11 sites) and di-n-butylphthalate (9 sites). Methanol or etha-
nol was not detected in leachate from any site. The various
ethers, esters and aldehydes were infrequently detected in low
concentrations. These three groups were not well represented
by any particular compound.
• Methylene chloride accounted for approximately 61% of the
halogenated hydrocarbon occurrences. Dichlorinated benzenes
and chlorobenzene accounted for about 13%, but these com-
pounds generally were not widely distributed and only occur-
red at less than half of the sites. The compounds detected in
samples from the greatest number of sites were methylene
chloride (13 sites), trichloroethylene (11 sites), chloroform
(10 sites), tetrachloroethylene (7 sites) and chlorobenzene (6
sites).
• Organic bases were present in leachates from nine sites. A single
organic base did not occur at half or more of the sites. Al-
though aniline ranks first by a large margin in the mean mole
fraction percentage represented, it was detected in samples
from only 3 of the 13 sites sampled.
• Toluene, benzene and other alkyl-substituted aromatics
accounted for approximately 92% of the aromatic hydrocar-
bon class. The aromatic hydrocarbons detected in samples
from the greatest number of sites were toluene (13 sites), ben-
zene (12 sites), total xylenes (11 sites), ethylbenzene (10 sites)
and naphthalene (4 sites). Toluene ranks first by a large mar-
gin in the mean mole fraction percentage represented.
• Aliphatic hydrocarbons occurred infrequently and were only
detected in samples from 3 of the 13 sites.
Pesticide Data Results
A GC/ECD analysis for PCBs and chlorinated pesticides was
carried out on the sample from Site 12, at which 70% of the
wastes were PCB-contaminated materials. Seven different PCBs
and pesticides were detected in the sample. In order of concen-
tration from highest to lowest (injig/1) the compounds were: en-
dosulfan sulfate (14.8), endrin ketone (11.4), heptachlor epoxide
(8.6), dieldrin (4.5), 4,4'-DDD (2.2), endrin (1.9) and alpha-
BHC (1.7). The combined contribution of these substances was
negligible at less than 0.01 mole fraction percentage. In addi-
tion, the above compounds accounted for only a very small part
of sample analytical TOC.
RECOMMENDATIONS REGARDING SYNTHETIC
LEACHATE FORMULATION
The results of this study do not collectively characterize any
particular leachate which was generated by any particular waste
or land disposal unit. Instead, as intended, the datas represent
an integration of leachate qualities exhibited by a variety of pro-
fessionally operated hazardous waste landfills. A synthetic leach-
ate for actual liner testing could not be formulated based on a
4% characterized organic fraction. Organic compounds that exist
within the 96% of uncharacterized TOC can impact the effective-
ness of liners and thus deserve to be represented in a synthetic
leachate. Nevertheless, useful information about the composition
of actual leachates has been revealed, particularly with respect to
the relative distribution and representation of the six organic
classes. Additionally, recommendations can be made in regards to
approaches for future studies which would generate a more com-
plete data base on organic constituents.
The study did characterize completely the concentrations of
priority pollutant metals in the various leachates, finding that
the most common metals were arsenic, selenium, nickel and zinc.
Additionally, other parameters were quantified for many of the
samples and demonstrated a range of values. Nevertheless, liner
LEACHATE FATE & CONTROL 239
-------
compatibility tests have shown that heavy metals in saturated
solutions generally are compatible with flexible membrane liners
and that inorganic constituents mostly affect only soil and clay
materials.2'3 Additionally, reference materials regarding the im-
portance of cyanide, redox potential and COD with respect to
leachate and liner compatibility are scarce. Most, if not all, liner
materials also are affected by very high or very low pH values.
For all of these reasons, only guidelines for the selection of organ-
ics and pH levels are recommended.
The pH values which were reported during this study ranged
from neutral to mildly alkaline. Based on these results, a value
range of 7±2 is proposed as a reasonable pH for a synthetic
leachate.
A synthetic leachate also should be approximately 99% water
and 1 % organics by weight. This estimate is based on an analyti-
cal average TOC of about 0.3 g/100 ml of sample, or about 0.3%
carbon. This amount of carbon would produce a weight of 1 g (or
less) of organic compounds/100 ml.
Several approaches can be taken toward the formulation of a
synthetic leachate once a sufficiently complete data base is gen-
erated on the organic constituents of actual hazardous waste
leachates. Tables 3 and 4 present examples for three such ap-
proaches by using the results of this study. These formulas should
be viewed only as prototypes, intended only to illustrate possible
approaches to leachate formulation, and not as strict examples of
what constituents and concentrations should be in such formula-
tions.
Table 3
Example of a Generic Synthetic Leachate Formulation
Chemical Typ»
ORGANIC ACIDS
Phenols
Carboxylic AcWt
Example(a)
Phenol, Cmote
Benzole, Hexanoic
Mole Fraction
Percentage
21
16
OXYGENATED/HETEHOATOMIC
HYDROCARBONS
Ketones
Alcohols
Acetone, 2-Bulanone, 26
4-Methyl-2-penUnone
Benzyl, Hexanol K)
HALOGENATED HYDROCARBONS
ORGANIC BASES
AROMATIC HYDROCARBONS
ALIPHATIC HYDROCARBONS
Methytene Chloride,
Chloroberuene
Aniline
Toluene, Benzene
Hepudecane
11
7
6
1
Table 3 presents a generic synthetic leachate formula; it sim-
ply proposes at what proportions the organic classes should be
represented, as supported overall by a data base. Each organic
class is represented by only a few specific compounds (such as
those given as examples in the table) at the respectively appro-
priate mole fraction percentage. The constituents and class pro-
portions should be supported by representations in the data base.
For example, based on the results of this study and as presented
in the table, the organic acid group consists of representative
phenols and carboxylic acids in approximately equal proportions
with respect to mole fraction; the oxygcnated/heteroatomic
group consists of representative ketones and alcohols, in a ratio
of about two to one, respectively.
Table 4 presents two synthetic leachate formulas which are
more chemically complex and specific than the generic formula
of Table 3. Each organic class still is represented in the formulas
by that proportionate amount supported by the overall data base,
but many more chemicals are selected to represent each class.
Table 4
Example* of Two Specific Synthetic Leachate Formolitlou
Compound Contribution as a Mole Fronton
(m.M Pareamege
Compound
Synthetic Uachate A
Chemical* Occurring
« > S CHM
Chemlcafc Occurring «
Average ConceiMiiilMi
J I* «>•'. («W)
ORGANIC AGIOS
Phenol
4-M*Ihylph*nol
2-MethvtprMnol
2.4-Oimetnrlpnenol
2-MMhytpfOpenoic Add
BenioK Add
Buianofc Add
Pmunoic Acid
HwanoJc Ad*
2 Einytwunote Add
Subtotal
OXYOENATED/HETEHOATOMIC
HYDROCARBONS
2-Butenow
4-MMhyl-2-penunane
M-n-buiytphtheiau
Benzyl Alcohol
Subual
HALOGENATEO HYDROCARBONS
Mwhytene CMorid*
U-tMcMoiDtMrum
CMorevofiTt
•bliKhtonthylena
t.l.MHchkxontim
n*n»-1.2 ChcNonxthyton*
Subtotal
ORGANIC BASES
Anttnt
N.N-OknMhytacramida
Subtotal
AROMATIC HYDROCARBONS
IbkMnt
Etnytwuene
XytoneU)
Benzent
Subnal
12%
6%
3%
2%
t%
8%
36%
17%
S%
3%
2%
1%
8%
36%
5%
1%
1%
1%
1%
1%
1%
11%
7%
7%
3%
1%
1%
1%
6%
12%
(%
6%
1%
6%
4%
1%
2%
7%
4%
9%
2%
11%
3%
4%
6%
6%
The specific formulas differ based on the criteria used to select
the chemicals and the respective proportions. The criterion for
chemical inclusion in Synthetic Leachate A is the frequency of
chemical occurrence in samples, i.e., a chemical is included if it
was detected in leachates from five or more sites. The criterion
for chemical inclusion in Synthetic Leachate B is the detected
concentration of a chemical, i.e., a chemical is included if it was
detected at average concentrations greater than 1.0 mole frac-
tion percentage. Chemical class and chemical proportionate con-
tributions to the synthetic leachate are shown in the table by a
mole fraction percentage and again should be dependent on the
supporting data.
The leachate samples collected during this study were approx-
imately 1% organic by weight. Organic concentrations can vary
with time and location within a site as the wastes age and change
in composition. Additionally, a punctured and corroded con-
tainer can result in a localized and highly concentrated organic
contact with a liner. Compatibility tests which use a synthetic
leachate containing an organic portion much greater than 1*
may be performed to represent such a situation.
RECOMMENDATIONS REGARDING ANALYTICAL
PROGRAMS FOR SIMILAR STUDIES
Subsequent leachate characterization studies ideally should in-
clude analytical programs which employ state-of-the-art teen-
240 LEAOHATE FATE & CONTROL
-------
niques designed to more fully characterize the organic materials.
Studies initially should be limited in scope to characterizing leach-
ates from one or two facilities and thereby first evaluate the ade-
quacy of any proposed analytical program. The analyses of sam-
ples from sites which accept a wide variety of waste types, such
as commercial facilities, would probably best gauge a program's
ability to identify a variety of compounds.
Based on observations regarding the limitations of this study's
analytical scheme, the following approaches are recommended
with regard to subsequent studies:
• Total recoverable oil and grease analyses could be performed
on the samples to improve the mass balance results (i.e., the
agreement between analytical and calculated TOC). This in-
formation could be very helpful in characterizing at least part
of the organic fraction.
• In addition to carrying out oil and grease extractions, other
separation procedures could be attempted. Silica gel column
chromatographic separation into polar, aromatic and aliphatic
fractions before GC/MS analysis would permit better separa-
tions by GC and more reliable identification by MS. Also, a
TOC or oil and grease analysis on an aliquot of each column
chromatographic fraction would allow an assessment of
material balance during analysis.
• Alternatively, general chemical classes could be analyzed,
rather than specific organic compounds. For instance, total
inorganic halogen, total phenols and oil and grease could be
included as key parameters.
• A determination of the amount of water could be performed
on the sample. This procedure would give direct information
about the extent of the aqueous portion of the leachate.
• A determination of whether the leachate sample is homogen-
ous or has a separable organic fraction that either floats or
sinks could be made. This factor would determine whether
or not a mainly aqueous phase or a mainly organic phase is in
contact with the liner. An analytical scheme could be devel-
oped, if preferred, only for that phase in contact with the liner.
At the writing of this paper, another U.S. EPA-sponsored
study is underway which incorporates some of the above recom-
mendations. This effort's analytical scheme hopefully will char-
acterize more fully the organic content of leachate. The first
phase of this new study involves the application of the analyti-
cal program to one sample to gauge its effectiveness. If the initial
results are not satisfactory, changes may be made to this pro-
gram's scope before its application to two additional samples.
CONCLUSIONS
The routine analyses of 13 hazardous waste leachate samples
resulted in the complete characterization of priority pollutant
metals and the incomplete characterization of organic constit-
uents. However, the results did provide valuable information re-
garding the relative distribution and representation of six organic
classes.
Nevertheless, a synthetic leachate could not be formulated
based on these results alone. However, several approaches can
be suggested regarding the selection and relative concentrations
of constituents in a synthetic leachate formula for consideration
once a sufficient data base is available. Such approaches might
include the development of a generic formula in which each
organic class is represented by a few of the compolunds most
commonly encountered in actual leachates. Other approaches
might include developing formulas in which many more chemicals
are represented. The criteria for chemical inclusion in these more
specific formulas might be based on whether the chemicals fre-
quently occurred in a number of actual samples or whether the
chemicals were detected above a certain proportionate concen-
tration.
Future studies should employ an analytical program which is
specifically designed to more comprehensively characterize the
organic components of actual leachates. This approach is partic-
ularly relevant with respect to formulating synthetic leachates for
liner compatibility studies because organics have been particu-
larly aggressive agents toward such liners. A study which incorpo-
rates such an analytical program is currently underway and is
being sponsored by the HWERL of the U.S. EPA.
REFERENCES
1. Bramlett, J.A., Furman, C., Johnson, A. and Nelson, H., "Com-
position of Leachates from Actual Hazardous Waste Sites," Pre-
pared for the Hazardous Waste Engineering Research Laboratory,
U.S. EPA, Cincinnati, OH, September 1985.
2. Stewart, W.S., "State-of-the-Art Study of Land Impoundment Tech-
niques," EPA-600/2-78-196, 1978.
3. Haxo, H.E., et al., "Lining of Waste Impoundment and Disposal
Facilities," EPA-530/SW-870/NTIS PB 81-166365,1980.
LEACHATE FATE & CONTROL 241
-------
Environmental Behavior of Polynuclear Aromatic
Hydrocarbons at Hazardous Waste Sites
Paul C. Chrostowski, Ph.D.
ICF-Clement Associates
Washington, D.C.
Lorraine J. Pearsall
Silver Spring, Maryland
ABSTRACT
Complexities in the analysis and environmental fate of poly-
nuclear aromatic hydrocarbons associated with inactive wood
treating and gasification sites have led to problems in interpre-
tation of results. This paper presents a preliminary investigation
of a methodology developed in response to these problems. A
chemometric profiling technique involving pattern recognition is
proposed and investigated in relationship to source apportion-
ment and environmental fate and transport. Examples of PAH
profiles from several inactive waste sites are examined and in-
terpreted regarding site management.
INTRODUCTION
Polynuclear aromatic hydrocarbons (PAH) constitute a diverse
group of several hundred organic compounds consisting of at
least two fused benzene rings. From the environmental health
standpoint, PAHs are important due to their mutagenicity and
potential human carcinogenicity.
Soil and groundwater contaminated with PAHs have been
found at numerous hazardous waste sites associated with coal gas-
ification industries or wood preservation with creosote. PAHs are
ubiquitous in nature, being formed by combustion and possibly
by biosynthetic processes. Several routes exist for migration of
PAHs from contaminated soil. The most important routes are
runoff with subsequent deposition in a surface water body, trans-
port in the subsurface both in dissolved form and as a non-
aqueous plume and entrainment of dust contaminated with PAHs
by wind. Once PAHs have migrated from a site, it is difficult to
ascribe them to a particular source due to their ubiquity and the
fact that individual compounds are subject to different fate and
transport processes. This situation causes problems related to
effectiveness of source control remedial measures; if the source is
ambiguous, it is difficult if not impossible to effectively design a
remedial program to control it.
BACKGROUND OF METHOD DEVELOPMENT
Although coal tar and creosote are the primary manufactured
materials containing large amounts of PAHs, they have been
found in virtually all media under a variety of circumstances.
Table 1 presents a compilation of materials which have been
analyzed and found to contain substantial quantities of PAHs.
Positive identification of any one PAH mixture is a difficult
task due to the complexity of the chemical composition. Not
only can a single mixture contain literally hundreds of PAHs,
but there also is considerable diversity between batches. The task
is further complicated by the effects of fate processes on the mix-
ture which often result in a loss of the lower molecular weight
compounds which are more volatile and more water soluble. An
early attempt at a chemically definitive definition of creosote was
published by the U.S. EPA.' The method involved measuring
phenanthrene and carbazole in environmental samples. If the
ratio of these compounds is between 1.4:1 and 5:1, the pres-
ence of creosote is indicated. Experience since the publication of
this method, however, has led to the conclusion that the ratios are
not reliable due to differential fate processes operating on the two
compounds.
Table 1
Environmental Distribution of PAH
• Coal and Related Products
Asphalt, Coal Tar, Coal Tar Pitch, Petroleum Jelly
• Food
Smoked Ham, Broiled Meal, Fish, Sausage, Margarine, Spinach,
Orange Rind, Sunflower Oil, Onion Peel
• Ail
Urban Air, Automobile Exhaust, Cigarette Smoke
• Soil
• Water
• Oils
Used Motor Oil, Creosote, Used Cutting Oil, Bunker C Fuel, Crude
Oil
• Sewage Sludge
Source: Referencrs "" tod 8.
One important step in the solution of the problem has been the
institutionalization of the number and identities of PAHs meas-
ured in environmental media and publication of standardized
laboratory techniques. Before the advent of gas chromatography/
mass spectroscopy (GC/MS) and High Performance Liquid
Chromatography (HPLC) techniques, PAH analyses reported in
the literature were often a function of the capabilities of the in-
dividual analyst. The net consequence of this was that results
from different laboratories were not comparable. Table 2 pre-
sents a matrix of PAHs measured in various media by different
laboratories. Note that these differences are not in PAHs found,
but in PAHs sought. Other problems in comparability of results
have involved the complex and often confusing nomenclature of
PAHs in addition to the existence of a plethora of extraction and
analytical techniques.
Since the publication of the U.S. EPA's priority pollutant list,
most measurements of environmentally important samples have
been limited to the 16 priority pollutant PAHs listed in Table 1
The U.S. EPA's hazardous substance list for Superfund contract
242 LEACHATE FATE & CONTROL
-------
laboratory program analysis also includes 2-methylnaphthalene
among the PAHs routinely measured. Additionally, the U.S.
EPA approved GC/MS or HPLC methods5 are used for the
analyses, and the nomenclature used in Table 2 has been almost
universally adopted. This has led to standardization across in-
vestigations and subsequent comparability of results.
Table 2
Variation in Analytes Sought
Nap thai ene
Blphenyl*
3-Methylnapthalene
Acenapthene
Fluorene
Phenanthrene
Anthracene
Fluoranthene
Pyrene
Benzo ( a) f luorene
Benzo ( a) anthracene
Chrysene
Benzo(b)fluoranthene
Benzo (k)f luoranthene
Benzo(a)pyrene
Benzo(ghl)perylene
Benzo (h)chrysene
Benzo ( J ) f luoranthene
Benzo(e)pyrene
Carbazole
Dlbenzot ah ) anthracene
Perylene
Dlbenzo ( def , mno ) chrysene
Nap tho ( 1 , 2 , 3 , 4-def) chrysene
Benzo(rst)pentaphene
Acenapthylene
Indeno (1,2, 3-cd ) py rene
Coal
Tar
(2)
X
X
X
X
X
X
X
X
X
X
X
X
x
x
x
x
Creosote
(3)
X
X
X
X
J£
J[
JJ
x
X
JJ
X
X
X
X
Air
Partlculate
M>
X
X
X
X
x
x
X
Priority
Pollutant
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
•Not strictly a PAH, but often Included In PAH analyses.
One analytical problem which has not been adequately treated
by current attempts at method standardization concerns resolu-
tion of isomers and/or co-eluting compounds. At a coal tar or
creosote site, each sample may consist of hundreds of PAHs. Due
to their structural and physicochemical properties similarities,
there is an excellent chance that some of them may co-elute from
a chromatographic column. For example, in the U.S. EPA's gas
chromatographic method for PAHs (Method 610), the two ben-
zofluoranthenes are co-eluting as are three other pairs of com-
pounds. The benzofluoranthenes also co-elute by the GC/MS
method (Method 625). It is likely that other compounds also may
be present but unresolved. For example, other benzofluoran-
thene isomers could be in the sample, however, the results may
be reported only as the sum of benzo(b)- and benzo(k)-fluoran-
thene.
The problem is compounded by the inability of mass spectro-
metry to distinguish among structural isomers. In one chroma-
tographic run with Method 625, an unknown at a retention time
of 14.1 min was identified as a dimethylnaphthalene isomer. The
MS library suggested 10 different isomers with quality indices
from 671 to 719. It was not possible to distinguish among the dif-
ferent isomers or to definitively state that only one isomer was
present.
During the time that standardization in PAH analysis was
occurring, advances were occurring in chemometrics, especially
with regard to pattern recognition and analysis of chromato-
graphic results. A recent symposium sponsored by the American
Chemical Society6 presented results of both chemical and statisti-
cal analyses for pattern recognition. Many of these techniques
are quantitative and rely on multivariate statistical analysis. Be-
fore embarking on an application of these methods to PAHs at
hazardous waste sites, it was decided to conduct a preliminary
study to assess the suitability of a pattern recognition technique
for environmentally important PAHs.
The technique proposed for PAH profiling involves visual
comparison of patterns of histograms which describe PAH con-
centrations. To utilize the same scale for all measurements, it was
decided to normalize the histograms with respect to the concen-
tration of an individual PAH. Benzo(a)pyrene [B(a)P] is the PAH
usually considered to be of greatest health significance and is
therefore sought most frequently by analysts. For this reason,
B(a)P was chosen as the compound to be used for normalization.
In general, there is good correlation among several physico-
chemical properties of PAHs including number of benzene rings,
molecular weight, aqueous solubility and vapor pressure (Table
3). To enable the histograms to convey the maximum informa-
tion (i.e., to use them in understanding environmental fate and
transport), it was decided to order them on the basis of molecular
weight. The histograms developed in this research thus show
abundance relative to B(a)P on the ordinate and increasing molec-
Table 3
Physicochemical Properties of Priority Pollutant PAHs
Compound
Naothalene
Acenapthylene
Acenapthene
Fluorene
Phenanthrene
Anthracene
Fluoranthene
Pyrene
Benzo(a)anthracene
Chrysene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(k)fluoranthene
Indeno(1,2,3-cd)pyrene
Benzo(ghi)perylene
Dibenzo(a,b)authracene
Abbreviation
NAP
ACY
ACE
FLU
PHE
ANT
FLA
PYR
BAA
CHR
BAP
BBF
BKF
IPY
BGP
DAA
Molecular
Weight
128
152
154
166
178
178
202
202
228
228
252
252
276
276
27-8
Number of
Rings
2
3
3
3
3
3
A
4
4
4
5
5
6
6
5
Vapor Pressure
(torr)
Not
5
5
6.8
1.9
6.8
1
Not
5.5
9.6
0.0492
Available
x 10~3
x 10~3
x ID'4
x 10~4
io-5
x 10~7
x 10~7
Available
x 10~9
x 10~1:L
20-10
ID
Water Solubility
(mg/1)
34,400
3,930
3,420
7,900
1,290
70
260
140
14
2
3.8
0.88
62
0.26
0.5
Sources, References 9, 10, 11.
LEACHATE FATE & CONTROL 243
-------
ular weight on the abscissa. The method is illustrated in Fig. 1.
In an effort to test the method, several samples from the litera-
ture were normalized and plotted as histograms (Fig. 2). The re-
sults show that there are clear differences among samples of coal
tar, coal tar pitch, used motor oil and urban air. The results also
show that there is good precision between duplicate samples.
These results were sufficiently encouraging to expand the inves-
tigation to PAHs found at hazardous waste sites and to the com-
plete suite of priority pollutant PAHs.
RESULTS
Several hypotheses were posited for testing in this portion of
the investigation. The first concerned reproducibility of profiles
from the same medium at the same site. Profiles of two sam-
ples of soil PAHs taken from an inactive wood treating site con-
taminated with creosote are shown in Fig. 3. The prifilcs are quite
similar for the two samples. Profiles of two samples of soil PAHs
from an inactive coal gasification site are shown in Fig. 4. Again,
a strong similarity is noted between the profiles. Also, there is a
strong dissimilarity between the wood treating (creosote) and
gasification (coal tar) samples. This result appears to confirm the
second hypothesis—that there is a recognizable difference be-
tween materials of different chemical origins.
The next hypothesis tested was that of consistency between
samples of similar materials from different sites. Fig. 5 shows the
results of profiling PAHs from an inactive gasification site
located over 1,000 miles from the previous site. Despite some
variation in the two samples, it is relatively easy to recognize the
similarities between these samples and the soil samples shown in
Fig. 4.
C««l T«f Pilch
i I I I I
u»»0 Uolai OH
Figure 2
Profiles Taken from Incomplete Literature Data
o
e
•D
3
a
E
a >. u D lu
o 0 ° 0 0 -
Molecular Weight
Figure I
Example of a Profile Histogram
PAHs may undergo numerous fate and transport processes in
the environment. Among the various physical processes, move-
ment of non-aqueous plumes, dissolution, sorption and volatili-
zation are most significant. Among chemical processes, biotrans-
formation in soil or aromatic substitutions in air are most impor-
tant. The testing of hypotheses concerning fate and transport was
the next stage in development of the profiling process.
Figure 3
Examples of Creosote Adsorbed to Soil
244 LEACHATE FATE & CONTROL
-------
I I
I I I I I I .
JII
Figure 4
Examples of Coal Tar Adsorbed to Soil I
Adsorbecf
Dissolved
, . 1 1
1 1 1 1 1 1 , 1
I I I I
Figure 5
Examples of Coal Tar Adsorbed to Soil II
_L
i I i
Figure 6
Differences Between Liquid Adsorbed Coal Tar and Coal Tar
Adsorbed to Soil
Figure 7
Differences Between Dissolved and Adsorbed Coal Tar
1 1 1
1
Mill,
Coal Tar
I , , i I
Unknown
J_L
Uncured Asphalt
Figure 8
Analysis of an Unknown
LEACHATE FATE & CONTROL 245
-------
The function of these hypotheses was to determine if the pro-
filing technique accurately reflected known environmental pro-
cesses undergone by PAH. Fig. 6 shows a comparison of liquid
coal tar PAHs to PAHs found in site soil. The material bound to
soil shows considerable attenuation in the lower molecular weight
range, especially with respect to naphthalene. This result is indica-
tive of the higher mobility or, alternatively, poorer adsorption
properties of naphthalene. Supporting data are not adequate to de-
termine the exact mechanism operating between the two samples.
Fig. 7 shows a comparison of creosote PAHs sorbed to soil and
PAHs found in surface water at a creosote site. For the water
samples, benzo(a)pyrene was found to be below the detection
limit, so one-half the detection limit was used as the normalizing
factor. The relative abundances are plotted on a natural log scale
due to exceedingly high values for the low molecular weight
PAHs. When viewing this figure, it should be remembered that
the true values for aqueous low molecular weight PAHs are more
than 100 times larger than the soil bound PAHs. Here, an enrich-
ment of low molecular weight materials in water relative to soil
may be noted. This condition probably is due to the higher aque-
ous solubilities of these materials.
Last, a hypothesis was formulated to test the utility of the tech-
nique as an aid in site remedial design. An investigation at a site
revealed soil contamination with PAH. At another portion of the
site, there was an asphalt road which had viscous uncured asphalt
as part of its sub-base. Since asphalt is composed of PAHs,
among other materials, it was hypothesized that the site contam-
ination was due to the presence of improperly cured asphalt. The
profiles of the unknown material, a genuine uncured asphalt
sample and a coal tar sample taken from another site are shown
in Fig. 8. Comparison of the profiles shows that the unknown
more closely matches the coal tar than the uncured asphalt. This
has obvious ramifications to site remediation. If only uncured
asphalt had been present, remediation could consist of excavation
of the old road. Contamination of soil with coal tar, however, in-
dicated another source and triggered additional remedial investi-
gation activity to define the extent of the contamination.
CURRENT AND FUTURE WORK
Several tasks are either planned or on-going to extend the utility
of this work. First, numerous additional analyses are being com-
piled and profiled to generate a comprehensive data base. Second,
methods of quantification of pattern recognition such as cluster,
correlation, factor, principal component and discriminant
analyses are being investigated for applicability to the method.
Last, the method is being applied to other environmentally im-
portant mixtures such as polychlorinated dibenzodioxins, poly-
chlorinated biphenyls, chlordane and toxaphene.
CONCLUSIONS
A pattern recognition technique for evaluating concentrations
of PAHs found at waste sites has been developed. Preliminary
results indicate that the method is reproducible, that it can dis-
criminate between various types of PAH containing materials,
and that it is responsive to environmental fate and transport pro-
cesses. The method also is potentially useful as an interpretive
adjunct to remedial design.
REFERENCES
1. U.S. EPA, Identification and Listing of Hazardous Waste. Federal
Register, May 19,1980.
2. Andersson, K., Levin, J.O. and Nilsson, C.A., "Sampling and
Analysis of Paniculate and Gaseous Polycyclic Aromatic Hydrocar-
bons from Coal Tar Sources in the Working Environment," Chemo-
sphere 12. 1983.197-207.
3. Lijinsky, W.. el al., "The Chromatographk Determination of Trace
Amounts of Polynuclear Hydrocarbons in Petrolatum, Mineral Oil,
and Coal Tar," Analyt. CHem., 35, 1963,932-956.
4. Katz. M. and Cha. C., "Comparative Distribution of Eight Poly-
cyclic Aromatic Hydrocarbons in Airborne Particulaies Collected by
Conventional High-Volume Sampling and Size Fractionalion." En-
viron. Sci. Tech. 14,1980,838-843.
5. U.S. EPA, "Guidelines Establishing Test Procedures for the Analy-
sis of Pollutants Under the Clean Water Act," Federal Register,
49, Oct. 28, 1984.
6. American Chemical Society, Symposium of Environmental Applica-
tions of Chemometrics, ACS 188th Annual Meeting, Philadelphia,
PA. Aug. 1984.
7. Edwards, N.T.. "Polycyclic Aromatic Hydrocarbons in the Tenet-
trial Environment—A Review," J. Environ. Qual. 12, 1983, 427-
441.
8. K.W. Brown and Associates, "Background Levels of Polynuctear
Aromatic Hydrocarbons," Report for Melvin Simon Associates,
Indianapolis, IN, July 1983.
9. Callahan, M.A., el al., "Water Related Environmental Fate of 129
Priority Pollutants," EPA-440/4-79-029,1979.
10. Radding, S.B., el al., "The Environmental Fate of Selected Poly-
nuclear Aromatic Hydrocarbons," EPA-560/5-75-009,1976.
11. Verschueren, K., Handbook of Environmental Data on Organic
Chemicals, 2nd Ed. Van Nostrand, New York. NY.
246 LEAdHATE FATE & CONTROL
-------
Creep Characteristics of Drainage Nets
Robert C. Slocumb
Darwin D. Demeny
Conwed Corporation
Minneapolis, Minnesota
Barry R. Christopher
STS Consultants, Ltd.
Northbrook, Illinois
ABSTRACT
Since the HSWA of RCRA were signed into law in November
of 1984, drainage nets have been increasingly used as the drainage
medium of choice for primary and secondary leachate collection
in hazardous waste containment facilities. An area of concern in
the use of plastics materials in these facilities is to what extent
creep, resulting from high continuous static pressure, affects
transmissivity of drainage nets over time.
Many drainage nets are available to collect leachate. They
could be made from polyethylene resins of a wide variety of den-
sities and manufactured by significantly different processes. The
question then is what effect, if any, do these different resin
variables have on the long-term performance characteristics of the
drainage nets?
In this paper, the authors provide a comparison of drainage
nets made from low, medium and high density polyethylene resins
with respect to their transmissivity characteristics under load. The
loads are applied to the samples for a minimum of 120 days and
testing will continue for an indefinite period of time into the
future (after presentation of this paper). The effect of creep on
transmissivity is discussed and actual performance data are fitted
to well-established mathematical models available in the literature
and developed for polyethylene. These models are then used to
project long-term transmissivity performance (30 years +) of
drainage nets.
INTRODUCTION
The use of plastic nets to provide liquid and gas drainage in
waste impoundments is finding increasingly wide-spread accep-
tance due to the benefits these nets provide over traditional
granular materials. These benefits are both economic and perfor-
mance related and are well documented.1'2-3
Nets are an effective drainage medium because they have good
flow properties at high static pressures and are resistant to
chemical attack. They consist of two sets of crossing strands in
which the strands of one set lie on top of strands of the other set
forming a biplanar structure (Fig. 1).
The two sets of strands create two sets of channels which can
carry fluids. The biplanar nature of these nets provides high fluid
flow rates and permits flow even under conditions in which the
channels of one set are blocked by flexible contact materials. The
various types of drainage nets available can be characterized ac-
cording to the following properties:
Resin type
Thickness
Density (foamed vs. unfoamed)
Weight per unit area
Porosity
These nets can have significantly different characteristics with
respect to their ability to provide fluid flow when subjected to
relatively high static pressures. Their ability to maintain the
desired flow properties over time can also vary, and selection of
the proper type for a given application requires an understanding
of the differences among these products. The object of this
research was to evaluate the flow (transmissivity) vs. creep
characteristics of drainage nets primarily with respect to the first
of the aforementioned properties—resin type.
MATERIALS OF CONSTRUCTION
Drainage nets generally are made of polyethylene. ASTM
defines polyethylene types in terms of density as follows:4
Type
I
II
III
IV
Table 1
ASTM Polyethylene Classifications
Specific Gravity (Density, g/cm3)
0.910 - 0.925
0.926 - 0.940
0.941 - 0.959
0.960 and higher
Figure 1
Biplanar Drainage Net
Types I and II are referred to as low-density polyethylene
(LDPE) and medium-density polyethylene (MDPE), respectively.
Type III is copolymer high-density polyethylene (HOPE), and
Type IV is homopolymer high-density polyethylene. Drainage
nets currently available are made from Type II polyethylenes.
Type III, as well as high-performance Type II resins, are made by
reacting ethylene with alpha-olefin comonomers such as butene
(C4), hexene (C6) and octene (Cg).
Drainage net physical properties are affected by the base resin
chosen. Such net properties as stiffness, tensile strength, elonga-
tion, ESCR and creep resistance are dependent to varying extents
upon base resin properties such as density, molecular weight
distribution, melt index and comonomer type.4-5 In general,
higher carbon comonomers produce higher performance
LEACHATE FATE & CONTROL 247
-------
resins.5'6'7
For these tests, three physically similar drainage net samples
were produced from each of three different resin types: I. II and
III. These samples had the following characteristics:
-WATER CHAMBER
T«bk2
Test Mifertiis
Ntl Ctiirscleriitki
But Kali Onracteriflks
Sample
11
n
Unit
Wl
Ibi/M
ft1
IJ5
138
136
Thickneu
(in )
0,1*0
0 169
0 161
Type
1
11
III
Rain
Deiuily
0925
09JJ
0951
Mill
Indtn
055
1 00
0 JJ
Copolymcr
Type
homopolymcT
odene
hnene
METAL PLATE
PNEUMATIC BLADDER
f METAL PLATE
NET
WATER BASIN
Figure 3
Transmit*! vity Tester
These nets were all compounded with 2% carbon black as an
additive. The samples then were subjected to 10,000 lb/ft2 static
pressure and periodic measurements of transmissivity were taken.
TEST EQUIPMENT
The test results presented here were obtained utilizing a uniaxial
permeameter (Figs. 2 and 3).
Figure 2
Transmissivity Tester
In this method, a test specimen, approximately 4.5 in. wide by
8.5 in. long, is positioned between a top plate with an inflow tube
and a base plate and then is placed in an overflow basin. The base
plate arrangement directs the flow through the plane of the
drainage material. For this test program, the prefabricated drain
extended to the front of the inflow port. Therefore, flow could
occur through the full drain simulating field conditions. This
long-term test was subjected to 10,000 Ib/ft* normal load by
loading the top plate with air pressure diaphragms.
TEST PROCEDURE
The samples were cut to dimension and placed in the tot
device.* Edges parallel to the flow were caulked to prevent
leakage around the net. The top plate was then put in place and
the edges were caulked. A pneumatic diaphragm wat installed
above the plate. Above this, another metal place wat boiled in
place to restrain the diaphragm. The tester was then placed in i
water basin to provide a reference water level.
•Tests conducted by STS Consultants, Ltd., Northbrook, DJinni,
The tester was Tilled with water, the diaphragm was inflated to
provide a 10,000 Ib/fU load and constant head tnuismtamtf
tests were run immediately. Tests were run at gradients of (US
and 1.5. Subsequent tests were run after 1, 2,4,8,16,30,Mind
100 days under load.
TRANSMISSIVITY CALCULATION
Transmissivity values were calculated as follows:
Sr = Q/B-i (1)
where:
9T = Transmissivity at the test temperature
T (cmVsec/cm)
B = Width of the sample (cm)
i = Gradient (dimensionless)
Q = Volumetric flow rate (cmVsec)
Sample temperature was maintained at ambient conditioni of
about 20 °C so no temperature corrections were applied.
EXPERIMENTAL RESULTS
Results obtained are displayed in Figs. 4(a-f). Results are pro-
vided for two different hydraulic gradients (0.2S and 1.SO) lor
each of the 3 resin types tested.
Resin type III showed a rapid decline in transmissivity begin-
ning approximately 10 days (250 hours) after the tests were in-
itiated. The rate of decline stabilized somewhat after 105 dap,
and the test was terminated to permit examination of the simp*
(Fig. 5).
The strands of the sample were found to be laid over from aw
original vertical alignment (Fig. 1) which decreased the n»M*'
effective thickness significantly. In addition, most of the junc-
tions at which the upper layer of strands crossed the lower layer of
strands were fractured or cracked. The strands them***1'
however, appeared to be undamaged.
248 LEACHATE FATE & CONTROL
-------
TRANSMISSIVITY vs TIME at i = 0.25
TRANSMISSIVITY vs TIME at i = 1.50
>"
g
H
CO
en
co u
25 co
co
CO
S-
p
4ffl e
4U) u u
1 H-— '
1 t^
1
1
•.1 i !• 1M IW« I.M ti
TIME /(DAYS)
Figure 4e
•
a
TPE n:
1
TIME /(DAYS)
Figure 4f
Figure 4
Results of Transmissivity vs. Time Tests Performed on
Type I, II and III Polyethylenes at 10,000 Ib/ft2
LEACHATE FATE & CONTROL 249
-------
Figure 5
Type III Polyethylene Net After 105 Days at 10,000 Ib/ft2 Normal Stress
DISCUSSION
Several mathematical model types are available in the literature
to which long-term compression creep data can be fitted.8'9 These
are generally power-law models of the type:
e = e0 + m I" (2)
where:
E = strain
t = time
f O09 and m = constants for constant stress
Findley and Tracy8 report good agreement of this model with
data obtained for polyethylene after 132,000 hrs (~ 16 years).
Rearranging Equation 2 and taking the logarithms of both sides
yields:
log (e - e0) = log m + n log t
(3)
Equation 3 represents a straight line with log (t - to) as or-
dinate, log t as abscissa and n as the slope of the line.
Values for these constants can vary within a fairly well docu-
mented range for various polyethylenes.8'10-"'12 A typical set of
values is shown in Table 3.
Table 3
Evaluation of (0, m and n In Equation 1 for Compressive
Creep Tests of Polyethylene al 75 °F.
(From O'Connor and Findley")
S.G Ml MWn «0* m* n a (lb/in.2
0.924
0.924
0.924
0.924
1.2
1.2
1.2
1.2
22,000
22.000
22,000
22,000
-0.40
-0.80
-1.20
-1.80
0.810
1.657
2.498
3.578
0.0208
0.0208
0.0208
0.0208
75
100
225
300
Figure 5
Type III Polyethylene Net After 105 Days at 10,000 Ib/ft2 Normal Stress
An estimate for the compressive creep of polyethylene at the
end of 262,000 hours (» 30 years) at a stress of 300 lb/in.2 using
these constants in Equation 1 yields:
t = -1.80 + 3.578 (262,000)0 M08
= 2.83<%
Findley9 and others have proposed a modification of this model
which yields somewhat different results where «0 and m are hyper-
bolic sine functions of stress a and are expressed by:
e0 = e'0sinh((7/ffe) (4)
m = m' sinh (a/am) (5)
where e I0, m',ae and am are constants of the material. Equation 2
can be written to incorporate Equation 4 as follows:
t = t\) sinh (a/ae) + m*t" sinh (a/am) (">• (g)
0 = 6.90 - 1.585 t 0.140
This model predicts that the transmissivity of the Type I poly-
ethylene reaches zero at approximately 35,000 hours (3Vi years).
It became apparent during the testing program that com-
pressive creep was not the only (or, in some cases, even the major)
source of thickness loss. Models such as Equation 8 are meant to
fit compressive creep data only. Non-creep factors which bias the
coefficients of these models can lead to incorrect conclusions
when extrapolated.
As previously shown in Fig. 5, the strands in the post-test type
III sample were laid over resulting in a net structure in which the
overall thickness was primarily a product of the strand width
rather than the strand height. The thickness loss (and thus the
transmissivity loss) exhibited in the type III sample is the sum
resulting from three separate sources of thickness loss:
250 LEACHATE FATE & CONTROL
-------
• Initial compression
• Corapressive creep
• Strand layover
These sources of thickness loss can be quantified best by using
the following technique on the type III sample since this sample
clearly underwent strand layover during the test.
5AMPLE CALCULATION
Initial Compression
Actual strain gauge measurements are used to obtain initial
;ompressive strain data for the type III net sample, for example at
: = 0.01 days:
Initial strain = 0.031 in. = e.oi
TO - «.01 = °-167 in- ~ °-031 in-
= 0.136 in. = T0i
where T.QI (subscripts in days) is the thickness from which the in-
itial transmissivity is taken (Fig. 4e). Therefore, there is a
thickness loss from T0 of 0.031 in./0.165 in. = 0.186 or 18.6%
which is a function of the initial compressibility (or compressive
resistance) of the sample. Note, however, that the initial
transmissivity 0.oi is measured at the T 01 datum.
Compressive Creep
The compressive creep thickness loss component at 105 days
7520 hrs) can be computed using Equation 2 and the extrapolated
/alues from Table 3 (for 1500 lb/in.2 static pressure):
e = - 3.06 + 6.15 (2520)0.0208
= 4.17% of T0 = 0.007 in.
TRANSMISSIVITY VS. DEFLECTION
1 THICKNESS LOST ((To - Ti)Ab) .100
*10t T10950
Figure 6
Transmissivity Retention vs. Thickness at i = 0.25
Strand Layover
Direct measurement of the strand width yields the following
result:
Top = 0.067 in.
Bottom = 0.057 in.
0.124 in.
(This value also can be approximated by a calculation which uses
the strand count, density, thickness and unit weight of the net.)
When laid over, the net thickness is the product of the sum of
the strand widths and the compressibility. (Ideally, this calcula-
tion should be corrected to reflect reduced pressure due to in-
creased strand contact area when laid over). Our measure of com-
pressibility is:
(T0 - f .Ol)/To = (0.167 in. - 0.031 in.)/0.167 in. = 0.814
Thus the approximate thickness after layover is:
(0.124 in.) (0.814) =0.101 in.
The total thickness after subtracting the compressive creep
component is:
0.101 in. - 0.007 in. = 0.094 in.
and as a percentage of T0:
0.094 in./0.167 in. = 0.563 or 56.3%
The total thickness loss from T0 due to initial compression,
compressive creep and strand layover is, therefore, 100% -
56.3% = 43.7%. Using Fig. 6, one would predict a transmissivity
retention (0io5/00) of 22a?o after 105 days (2500 hours).
The initial transmissivity of this sample was measured at time
101 which corresponds to a thickness loss of 18.6%, as previously
discussed, and from Fig. 6:
8 01 = 0.78
00
Therefore the actual transmissivity retention ratio at 105 days
(Fig. 4e)
.01
106
4.14
0.26
corresponds to a base transmissivity retention ratio of:
9.01 9 105
= (0.78)(0.26) = 0.20
'.01
or 20% which is in good agreement with our predicted results.
One can also project that the transmissivity at 262,000 hours
(30 yrs) will be reduced from this level by compressive creep strain
only (since strand layover of this sample has obviously occurred):
(%) = - 3.06 + 6.15 (262,000)0.0208
= .0491%
The thickness loss due to creep strain is, therefore:
(0.0491) X (0.167 in.) = 0.008 in.
which is an additional (0.008 in. - 0.007 in. =) 0.001 in. from
the 105-day value. The total thickness after subtracting the
30-year creep component is now:
0.101 in. - 0.008 in. = 0.093 in.
and as a percentage of T0:
0.093 in./0.167 in. = 0.557 or 55.7%
The 30-year (10,950 day) thickness loss from T0 due to initial
LEACHATE FATE & CONTROL 251
-------
compression, compressive creep and strand layover for the type
III sample is projected to be 100% - 55.7% = 44.3%.
Using Fig. 6, one would predict a base transmissivity retention
(010 950/0,,) of approximately 19% after 30 years (Table 5). This is
approximately equivalent to a transmissivity retention of 24% of
the initial transmissivity measurement taken at 10,000 Ib/fU.
Table 5
Projected vs. Actual Transmlsslvlty Retention
Type HI Simple
Actual
To - 0.16711.
Projected
Time
initial 0.167 — -p~
0.01 0.136 — 078
*I05 — 0.26 0.20
* 10,950 — N/A N/A
(30 yn)
T(ln) »I/».OI >l/'o
....
0.094 0.21 0.22
0093 024 0.19
after strand layover
It is apparent from the strand layover calculations that increas-
ing the strand width will have a significant effect on increasing the
30-year transmissivity in a layover condition. Of course, such a
product is also less likely to undergo such a layover.
It would be premature to extrapolate the performance potential
for the Type I and II resins because of the uncertain status of the
relative components of strand layover and compressive creep in
making up the model. The Type II polyethylene appears to
substantially out-perform the Type I resin up to 2500 hours (105
days), however. Note that the Type II 100-day transmissivity
retention ratio (0j/0.oi) is in excess of 80% (Fig. 4c,d).
Tests are presently underway to more accurately identify the
model coefficients with respect to:
• Resin type
• Comonomer type
• Specific resin properties such as tensile, modulus, compres-
sive resistance, etc.
CONCLUSIONS
The factors which cause a drainage net to lose thickness and,
therefore, transmissivity are:
• Initial compression
• Compressive creep
• Strand layover
Compressive creep appears to be a relatively small contributor
to overall thickness loss at the stress levels considered relative to
other sources of thickness loss, however.
A significant potential source of performance loss is strand
layover. Problems in this area can be avoided by:
• The selection of properly designed drainage nets
• The use of nets which have a significant margin of safety at the
targeted stress levels. (The nets evaluated in these tests are on
the lower performance end of products available, whereas the
pressures evaluated are on the higher end of pressures com-
monly encountered in these applications.)
Low compressibility (i.e., high compressive resistance) is a
desirable feature in a drainage net to minimize initial compression
as long as it does not result in a brittle product prone to fracture.
However, a drainage net which does suffer layover and even joint
fracture apparently will continue to function, albeit at a lower
level of efficiency.
Data of this type are not easily extrapolated because of the
dynamic nature of the transmissivity versus time plot. Component
modelling is probably a more accurate way to predict drainage net
behavior. In any event, tests of this type should be conducted for
periods of time greater than 120 days to facilitate trend identifica-
tion.
Finally, although this testing was conducted at room
temperature (approximately 20 °Q, the application temperature
for these products may be on the order of 10 °C lower. This would
tend to reduce any error in the estimation of strain due to com-
pressive creep which may be present in this analysis."-14
REFERENCES
1. William*. N. et at., "Properties of Plastic Nets for Liquid and Gu
Drainage Associated with Gcomembranes," Proc. International
Conference on Geomembranes, Denver, CO, 1984, 399-404.
2. Bonaparte, R., el at., "Innovative Leachate Collection Systems for
Hazardous Waste Containment Facilities." Available from Geo-
services Consulting Engineers, Inc.
3. Udwari, J. and Kittridge, J., "Designing of Double Lined Im-
poundments—Lessons Learned," Proc. Third International Confer-
ence on GtottxtUes, Vienna. Austria, 1986, 924-934.
4. See, for instance, Benham. J.V., "Polyethylene and Ethylene Co-
polymers," Modern Plastics Encyclopedia. 1985-1986. S2-54.
5. Phillips Petroleum Company, Technical Information Marten Poly-
olefin Plastics," Chemical Department, Plastics Division, Bartles-
ville,OK,2-lS.
6. Finley. S.. Plastics World, Nov. 1984, 38-41.
7. Lustiger, A. and Corneliussen, R.D., Modem Plastics, March 19S6,
74-82.
8. Findley, W. and Tracy, J., Polymer Engineering and Science, 14,
1974, 577-580.
9. Findley, W. and Khosla, SPE Journal, Dec. 1956, 20-25.
10. Findley. W., et at., ASME Journal of App. Mech.. 67-WA/APM-
10,1-10.
11. O'Connor, D. and Findley. W., SPE Transactions, 1962.273-289.
12. O'Connor, D. and Findley, W., ASME Journal of Engineering for
Industry, 1962, 237-247.
13. Trantina. O., Polymer Engineering and Science, 26,1986,776-780.
14. Turner, S., Polymer Engineering and Science, 1986,101-109.
252 LEACHATE FATE & CONTROL
-------
Innovative Engineered Systems for Biological
Treatment of Contaminated Groundwater
Paul M. Sutton, Ph.D.
Dorr-Oliver Incorporated
Stamford, Connecticut
ABSTRACT
Improved biotreatment techniques represent an economical
and effective means of complying with new environmental legisla-
tion calling for control of toxic and hazardous organic and in-
organic substances. Microbiological research has expanded
knowledge of the biotreatability of complex organics. By combin-
ing this knowledge with innovative reactor design concepts, Dorr-
Oliver has developed efficient engineered systems for treatment
and detoxification of contaminated water and wastes. The
systems are based on the aerobic and anaerobic biological fluid-
ized bed and membrane biological reactor concepts. Physical-
chemical mechanisms for contaminant removal are an inherent
part of the systems or can be integrated readily into the systems.
This paper describes the technologies and their benefits in treating
complex organics, discusses the technical and economic factors
dictating system selection and presents application information.
INTRODUCTION
Improved biotreatment techniques represent an economical
and effective means of complying with new environmental legisla-
tion calling for control of toxic and hazardous organic and in-
organic substances. Extensive research work at the government
and university levels and, to a lesser degree, by private industry
has expanded knowledge of microbial detoxification and/or
degradation of complex organics. In 1985 the U.S. EPA was in-
volved in the management of biotechnology research projects
such as biodegradation of 2,4-D, microbial dechlorination and
aerobic degradation of trichloroethylene.
Wastewaters normally are composed of a complex matrix of
various concentrations of compounds. These compounds may be
degradable, inhibitory or recalcitrant to various degrees. Physi-
cal-chemical treatment techniques may be required in order to
render the wastewater less inhibitory to microbial treatment or en-
sure the removal of non-biodegradable compounds. Physical-
chemical treatment normally is provided by the addition of unit
processes before or after the biological step. Integration of these
removal mechanisms into the biological step represents a cost-
effective treatment alternative if technically feasible.
Dorr-Oliver has developed efficient engineered systems for
treatment and detoxification of contaminated water and waste-
waters by combining the knowledge gained from biotechnology
research with innovative reactor design concepts. The systems the
company has developed are based on aerobic and anaerobic fluid-
ized bed and membrane biological reactor concepts. Physical-
chemical mechanisms for contaminant removal are an inherent
part of the systems or can be integrated readily into the systems. It
is the purpose of this paper to describe the technologies and their
benefits in treating complex organics, discuss the technical and
economic factors dictating system selection and present applica-
tion information.
FLUIDIZED BED AND MEMBRANE
BIOREACTOR TECHNOLOGIES FOR
TREATMENT OF COMPLEX ORGANICS
The biological process reactors available for wastewater treat-
ment can be classified according to the nature of the biological
growth in the system. Those reactors in which the active biomass
is suspended as free organisms or microbial aggregates can be
regarded as suspended growth reactors, whereas those in which
growth occurs on or within a solid medium can be termed sup-
ported growth or fixed-film reactors.
The fluidized bed reactor represents a highly efficient fixed-film
reactor in which biomass build-up occurs on an inert (sand) or ac-
tive (activated carbon, resin material, etc.) fluidized support
medium high in external surface area. The principles of the fluid-
ized bed process have been incorporated into full-scale aerobic
and anaerobic configurations through the development of the
Oxitron® and Anitron™ systems, respectively.
In the fluidized bed process (Fig. 1), the contaminated waste-
water and recycled effluent pass upward through the medium at a
velocity sufficient to expand the bed beyond the point at which
the frictional drag is equal to the net downward force exerted by
gravity. Once at or beyond this point of minimum fluidization,
the particles that make up the bed are individually and
hydraulically supported. These particles provide a large surface
area for biological growth, in part leading to the development of a
biomass concentration approximately five to ten times greater
Figure 1
Oxitron System Process Schematic
LEACHATE FATE & CONTROL 253
-------
than that normally maintained in a suspended growth system,
consequently reducing the required liquid contact time or
hydraulic retention time (HRT).
The fluidized bed bioreactor is extremely simple in design, con-
tains a piping to distribute the influent flow and has a component
to control the expansion of the fluidized bed. When biological
growth occurs on the fluid bed medium, the effective diameter of
the medium support particle increases and its effective density
decreases, resulting in an expansion of the fluidized bed beyond
that due to fluidization of the unseeded medium. It may be
necessary to control the biofilm thickness to prevent the density
of the biofilm-covered medium (bioparticle) from decreasing to
the point where bed carryover occurs. This control is accom-
plished by monitoring the bed expansion optically, carrying out
separation of the medium from the biomass if the maximum
specified bed height is reached and returning the medium to the
reactor.
The maintenance of a highly active biomass in a suspended
growth reactor is dependent on the performance of the
downstream solid-liquid separation step and subsequent cell recy-
cle. The membrane bioreactor represents an advanced suspended
growth reactor in which a high active microbial concentration
(12,000 to 30,000 mg/l volatile suspended solids) is achieved
through the use of ultrafiltration for biomass-effluent separation
and subsequent recycle to the biological reactor. Commercial em-
bodiments of the concept in aerobic (Fig. 2) or anaerobic con-
figurations are represented by the Membrane Aerobic or
Anaerobic Reactor System (MARS™).
Ml MUANf STATION
Figure 2
Aerobic MARS Process Schematic
The fluidized bed and membrane bioreactors will be most at-
tractive when the benefits of the systems can be realized due to
qualitative and/or quantitative characteristics of the wastewater
in question. The Oxitron/Anitron and MARS concepts overcome
many issues of concern in applying microbial methods for treat-
ment of hazardous wastewaters (Table 1).
Situations which require rapid treatment of the organic con-
taminants will favor these technologies versus alternative
biological systems. Microbial detoxification and/or degradation
of complex organics normally require the maintenance of a long
solids retention time (SRT) or cell residence time corresponding to
a slow net specific growth rate of the organisms in question. Ac-
cumulating a large biomass concentration in the fluidized bed or
membrane bioreactor allows efficient removal of complex organic
compounds at a short liquid contact time or HRT relative to more
conventional suspended growth (activated sludge, sequencing
batch reactor, aerobic/anaerobic lagoons) and fixed-film (down-
flow or upflow packed bed reactors) systems.
The fluidized bed and membrane bioreactors allow selective de-
velopment and reliable retention or microbial populations effec-
tive against specific complex compounds. The fluidized bed
Table 1
Issues of Concern In Blofreatmenf of Hazardous Waters and
Wastewaten Addressed by Fluidized Bed and/or Membrane
Bioreactor Concepts
issue
SM.VTIM
Efficient tr
SylUB UOMtt tut to loll Of
PMCtOr blOMII (ckUf<*f MO
MII Mttllno, cMncUrd-
llci).
l«lid-up U4 rtmitlon »f
blOMtt In IrMOwit of
MilU llrvMl low !• C0«-
UtlMllt COftC«*tr«tlO*.
Trttuvnt of llonljr o>fr>4-
Ibll or rtcjlcltnnt «•-
Long lolldi raunttoD tl«tt (urti) cu to
•ckfmd l« f1«M bod Md! ••triM Mortic-
ian it tMrt liquid co»Uct tlm.
UM of mt*tru» blorwctor pro»ldM •bwlitt
control of lloMII \nntarj. M«d-flli
Mtvn of fluU bftf tloructor clnlriztl OM-
cirn.
AMoluU blown ImMtary uwtrol In
brm blort«ct«r Itlll tllon •l
r*«iln4 »T for tr«iUnit. Fl«4-ftli N-
Uir« of fluid 0*4 «llow t«Hd-v»/r.tt.tl«
of klojan.
Cktricurlitlctlljr lo^ SITi mt tit of |rw-
•1«r »tmu4 urbo* U n»U t*t or pM-
dtr»d fr rttldXMlt)
• It ItlOCKUd (lorfted)
contMlfuntl.
Cll«liut«4 or •Inl>lli4 In fluid »M at m-
•rono blorvlctor by cMrtcUrlttlcllljr lo«9
WTl »d optlOMl UM of >ctl»Ud urbn.
Mlo* tfni>»t rtcirclt In fluid bed prorldd
food dllvtlon. Co^l«U-ali utirrt of *tn-
brtnc b1or««ct«r 4\lftntl Uilcont.
tlon of tattron >ltk «w of fcto* purl.
wid pn-dl«Ml«tlo«i illvliiiui ttrlo-
tj 0,
ClKricUrlltluUy lo«l S>T> rtult l> «l«l-
M! txccll blOMti production. Sloityastrt-
ttoti of c«rbon Btn-,Blztt Its repttcemt wtm
vitd «> vrdli In flyld bed or Mhcn added Is
po*4«r«d for« t« MMbrane bloreictor.
achieves this microbial retention through development of a
biofilm. A certain amount of uncontrolled biomass is lost from all
biofilm reactors; this loss is minimal in the fluidized bed reactor
since the design of the Oxilron/Anitron systems provides for con-
trol of biofilm thickness.
Biomass loss must be less than the rate of growth of new bio-
film. Since the rate of growth of new biofilm declines as the con-
centration of the contaminants of concern declines in the reactor,
the biofilm reactor may lose its efficiency and the reactor HRT
may have to be increased in order to maintain the required SRT.
The MARS bioreactor achieves a large biomass density by ab-
solute and controlled retention of all developed microorganisms.
The SRT can be controlled precisely by removal of excess biomass
directly from the reactor (Fig. 2). Precise SRT control prevents
the loss of specially selected microorganisms having thejcapability
to remove a specific compound or grow efficiently at very low
contaminant concentrations.
The characteristically long SRTs attainable in the fluidized bed
and membrane bioreactors minimize the changes of inhibition
due to microbially toxic or inhibitory feed inputs. Tolerance to
such conditions can be further achieved by promotion of physi-
cal-chemical adsorption through the use of granular activated
carbon (GAC) as the fluidizing medium in the fluidized bed reac-
tor and/or the addition of powdered activated carbon (PAQ to
the membrane bioreactor. The use of activated carbon in the
bioreactors provides additional benefits including more rapid in-
itial removal upon startup and a greater removal of slowly
degradable or recalcitrant compounds. Upon reactor startup, the
activated carbon removes these materials from the wastewater,
concentrating them on the carbon surface. With microbial
growth, biodegradation becomes an important removal mechan-
ism in addition to extending the life of the carbon through
bioregeneration.
Activated carbon in a biological reactor should reduce the vola-
254 LEACHATE FATE & CONTROL
-------
tilization of adsorbable compounds. Operation of the aerobic
MARS concept using pure oxygen as the source of oxygen, with or
without the addition of PAC, would reduce air stripping of vola-
tile organic compounds (VOCs) relative to conventional aerobic
systems. The Oxitron system represents the optimal choice in situ-
ations where environmental constraints dictate that VOC strip-
ping must be minimized. In the system (Fig. 1), required oxygen is
dissolved in the influent stream prior to entry into the fluidized
bed in a controlled fashion to ensure no excess oxygen is released
at the top of the reactor. The use of high-purity oxygen and pre-
dissolution ensures little or no release of volatile organics into the
atmosphere.
SYSTEM SELECTION
Selection of the fluidized bed or the membrane bioreactor for
treatment of a specific wastewater stream is dictated by both
technical and economic factors (Table 2). Although the mass
organic loading (flow multiplied by concentration) is a key factor
when determining the size of the biological reactors, the size of
the ultrafiltration unit of MARS is directly dependent on flow
rate. Consequently, relative to Oxitron/Anitron, this system is
often more cost-effective for treatment of lower volumes of
wastewaters.
Hazardous wastewaters containing degradable organic
suspended material and emulsified oil and grease are handled
more readily in MARS. The use of ultrafiltration for biomass-
effluent separation and subsequent cell recycle ensures retention
of such materials and subsequent biodegradation provided the
organisms responsible for their removal have growth rates equal
to or greater than the inverse of the SRT maintained in the
biological reactor.
The characteristics of the specific soluble organics contained in
a hazardous wastewater stream in terms of biodegradability, ad-
sorbability and volatility determine the applicability of the fluid-
ized bed and/or the membrane bioreactor systems with or without
the use or addition of activated carbon. Examples of complex
soluble organics treatable in aerobic versions of these systems are
provided in Table 3.
Table 2
Factors Governing Selection of Fluidized Bed versus Membrane
Biological Reactor in the Treatment of Hazardous Wastewaters
FACTOR
FLUID BED BIOREACTOR (OXITRON/ANITRON) VERSUS
MEMBRANE BIOREACTOR (MARS)
Effluent quality.
Membrane bioreactor normally will provide better
effluent quality as effluent will contain no sus-
pended solids.
Table 3
Examples of Complex Organics Treatable in Aerobic Fluid Bed
or Membrane Bioreactor Systems
SYSTEM
CHARACTERISTICS OF
APPLICABLE COMPOUNDS
EXAMPLE
Oxttron or
aerobic MARS
Oxltron
Oxltron with
carbon as
fluid bed
Mdlt
Oxltron with
carbon is
fluid bed
media or
uroblc MARS
with carbon
iddltlon
Aeroblcilly biodegrad-
able and not readily
volatilized
Aeroblcally biodegrad-
able and volatile or
seat-volatile
Not readily aeroblcally
biodegradable, volatile
or se«1-volatile, and
absorbable on carbon
Not readily aeroblcally
biodegradable, not readi-
ly volatilized but ab-
sorbable on carbon
Phenol. Acrylonltrlle, Hexa-
chloroethane
Carbon tetrachlorlde, Haptha-
lene, Ethylbenzene, Toluene,
Benzene. Methylene chloride.
Methyl ethyl ketone
Trlchloroethylene, Tetrachloro-
ethylene, l,2-d1chlorobenzene
1,2,4 trlchlorobenzene, Bts-
(-ethyl hexyl) pthalate. Penta-
chlorophenol
series operation of anaerobic and aerobic fluidized bed or mem-
brane bioreactors may be the most attractive flow scheme, de-
pending on the specific organics contained within the wastewater
and the degree of treatment required.
APPLICATIONS
To date, mobile/transportable and permanently installed Oxi-
tron/Anitron and MARS systems have been used for the treat-
ment of a number of wastewater streams containing a variety of
toxic organics and inorganic compounds. Example applications
are listed in Table 4.
Table 4
Applications to Date of Dorr-Oliver's Biological Systems
to Treatment of Toxic Organic Wastewaters
SOURCE
TYPE OF CONTAMINANTS
Automotive Industry
Paint solvents
- Hetalinrktng fluids
Chemical/Petrochemical Industry
- Process water fro*
synthetic fiber pro-
duction
011 refinery process
wastewater
Volatile organic compounds
Petroleum-based hydrocarbons, glycols,
autoes, wines, ethers
Acrylonltrlle and other organtcs
Methyl ethyl ketone, toluene, methyl
pyrrol(don and other organics
Treatment of highly
volatile organtcs.
Treatment of parttcu-
lite and soluble
organtcs.
Economics.
Little or no volatilization/stripping of organtcs
will occur tn Oxltron. More volatilization nor-
mally will occur tn MARS.
Parttculate organics are handled better tn MARS
due to retention by ultraftltratton component and
subsequent btotreatment. Fluid bed and membrane
btoreactor both handle soluble organtcs efficient-
ly-
Fluid bed Is often more cost effective than MARS
tn treatment of 'high* volume water and waste-
waters.
The anaerobic versions of the fluidized bed and the membrane
bioreactor systems may be attractive in situations where it is an-
ticipated that the treated effluent will be disposed of in a
municipal treatment plant. Treatment of a leachate from a land-
fill is an example where anaerobic pretreatment may be a more
cost-effective solution than aerobic treatment. Alternatively,
Synthetic Fuels
- Shale oil processing
wastewaters
- Coal liquefaction
process wastewaters
Iron and Steel Industry
Coke plant wastes and
blast furnace blowdown
Pulp and Paper Industry
XSSC corrugating mill
and hardboard mill
wastewaters
- Sulftte mill conden-
sates
Polycycllc organics, ammonia, organic
sulftdes, etc.
Phenols, ammonia, organic nitrogen
compounds and other organics
Phenols, polyaromatfc hydrocarbons,
nfa. etc.
Organic adds, alcohols, sulfur com-
pounds, etc.
Acetic add, methanol, furfural,
ammonia, sulfur compounds, etc.
Applications of the technologies for nitrate and nitrite-nitrogen
removal from groundwater and river water have not been includ-
ed in Table 4. These compounds normally are not considered tox-
LEACHATE FATE & CONTROL 255
-------
ic, although they can give rise to serious health issues. High
nitrate levels in drinking waters have been associated with metha-
emoglobinemia in infants and may influence human cancer in-
cidence through the formation of nitrosamines. Three of the 11
Dorr-Oliver fluidized bed commercial installations involve the ap-
plication of the technology for nitrate removal. One system is
located at a municipal water treatment plant and is designed to
treat up to 1 mgd of river water containing approximately 15 mg/1
of nitrate-nitrogen. The fluidized bed reactor of the system con-
sists of a 5.2 m2 rectangular tank 3.5 m high. A smaller transpor-
table fluidized bed reactor was operated at an industrial site
treating groundwater containing up to 60 mg/1 of nitrate-
nitrogen. The nitrogen originated from the use of sodium nitrate
in the manufacturing of rubber trim for the automotive industry.
Nitrate-nitrogen reductions greater than 90% were achieved at a
fluidized bed liquid contact time of less than 45 min.
Additional information derived from other applications of the
technologies follows.
Contaminant Source: Automotive Manufacturing
The painting of automobiles and light-duty trucks at assembly
plants has been identified by the U.S. EPA as a significant source
of volatile organic compound emissions. VOC emissions can be
reduced by process changes such as using water-based coatings or
powder coatings; however the change may not necessarily be cost-
effective. Carbon adsorption and incineration of airborne VOCs
are feasible control techniques, but again at very high costs.
Recently, a major automotive company completed an in-depth
study of options for controlling VOC emissions from paint spray
booths. It was demonstrated that significant portions of the
VOCs can be removed by existing Venturi scrubbers in the paint
spray booths and then biologically degraded in the Oxitron
aerobic fluidized bed system. The effluent from the biological
system was subsequently recycled to the paint booth to allow for
further VOC uptake (Fig. 3).
BOOTH
EXHAUST
PAINT
SPRAY
BOOTH
BOOTH WATER
RESERVOIR
OXITRON
BIOLOGICAL
REACTOR
BIOLOGICAL
SLUOOE
DIPOSAL
RECYCLED
WATER
PAINT
SLUDGE
REMOVAL
SYSTEM
PAINT I
SLUDGE 1
DISPOSAL
I igure 3
Oxitron VOC Control Concept
The fluidized bed reactor of the biologically based VOC control
system consisted of a 17.8 m* rectangular tank. The reactor was
5.0 m high and had a total organic carbon loading capacity of 2.8
kg/day. The fluidizing medium utilized in the reactor was quart-
zite sand.
Variable concentration levels of a wide variety of organic car-
bon compounds were measured in the feed to the fluidized bed
reactor including methanol, acetone, methyl chloride, isopropyl
alcohol, 1-propanol, methyl ethyl ketone (MEK), benzene,
toluene, 1-butanol and cyclohexanone. A performance assess-
ment indicated that little or no volatilization of the organics oc-
curred in the biological reactor. Although the efficiency of the
VOC control system depended on achieving a high volumetric
VOC removal rate (kg VOC/m'-day) versus a high percent VOC
reduction, percent removal information was determined for cer-
tain compounds at a relatively constant feed rate to the reactor.
The results (Table 5) were not derived under controlled conditions
and, therefore, only reflect the potential performance of the Ox-
itron system in this application.
Contaminant Source: Petroleum Refining
The process wastewafr from a Pennsylvania petroleum refiner
is treated in an on-site facility that uses flow equalization, free oil
removal, chemical emulsion breaking, flocculation and dissolved
air flotation. This conventional oily wastewater treatment scheme
was not able to achieve compliance with permit requirements dur-
ing spills of methyl ethyl ketone (MEK), toluene and N-methyl-2-
pyrrolidon (NMP), compounds used in the dewaxing and extrac-
tion unit processes associated with the manufacture of high quali-
ty lubricants. A transportable Oxitron unit was tested to deter-
mine its ability to handle the effluent from the oily wastewater
treatment plant during permit excursions associated with MEK,
toluene and NMP spills. The unit was operated under normal feed
conditions and (hen subjected to shock inputs of these organics.
The results in Figure 4 are representative of the performance of
the Oxitron system under such conditions.
TibleS
Results Indicating Performance Potential of the Oxitron System
in the Treatment of Painl Solvent!
CONPOUM
knztM
t-bouiwl
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».i
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ilium EFFIUEVT
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4
4
4
4
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t) feted on vOltflat
fl«td1l«4 b*d.
The aerobic fluidized bed produced an effluent biochemical
oxygen demand (BOD5) of approximately 10 mg/1 prior to a
shock loading of MEK and toluene (Fig. 4). Although the shock
loading resulted in the feed BOD5 increasing from approximately
60 to 220 mg/1, the impact on the effluent from the fluidized re-
actor was relatively insignificant. These results illustrate the abili-
ty of the Oxitron system to absorb shock loads of complex
organics.
Contaminated Source: Metalworking Operations
Major segments of the metalworking industry are converting
from petroleum and oil-based coolants used for machining and
hydraulic applications to synthetic and semi-synthetic coolants.
The synthetics are based on water soluble organics such as com-
plex glycols, amines, amides, esters and fatty acids. A major con-
cern relating to the use of synthetic coolants for the industrial user
is the incompatibility of the compounds with existing on-site
wastewater treatment systems. The true synthetic coolants con-
tain no petroleum oil, thus the organics are completely water solu-
ble and normally cannot be separated from the water phase as can
the oil by breaking the oil-water emulsion. Therefore, the conven-
256 LEACHATE FATE & CONTROL
-------
240-
•180-
60-
FUIIDIZEDBEDHRT
FEED D
EFFLUENT •
55MIN
\
53 55 57 59 61
DAYS SINCE REACTOR START-UP
63
Figure 4
Response of Oxitron System to Shock Loading of MEK and Toluene
tional oily wastewater treatment system will not effect removal of
the soluble organics, and the plant effluent will contain significant
levels of BOD5, chemical oxygen demand (COD) and organic
nitrogen compounds.
In 1984 and 1985, General Motors' Hydramatic plant in Ypsi-
lanti, Michigan, conducted extensive pilot studies involving the
Oxitron system. On the basis of the results of those studies, a full-
scale Oxitron system is being installed at the Hydramatic plant for
the treatment of the effluent from the conventional oily
wastewater treatment system. The pilot plant results indicated
that, although a 98% BOD5 reduction could be achieved in the
Oxitron system, a large fraction of slowly biodegradable or
recalcitrant organic carbon limited the COD removal to an ef-
fluent level of approximately 450 mg/1. A study currently is being
completed to assess the capability of Oxitron and aerobic MARS
reactors operating in parallel to reduce this COD level.
The fluidized bed reactor contains granular activated carbon as
the fluidizing medium, and powdered activated carbon is being
added to the MARS reactor. Combined biodegradation and phy-
sical-chemical adsorption is expected to result in a significant
degradation of this slowly biodegradable/recalcitrant organic
material. Preliminary results indicate that the systems can reduce
the COD level to less than 80 mg/1.
CONCLUSIONS
Dorr-Oliver has developed efficient engineered systems for
treatment and detoxification of contaminated wastewaters. The
systems are based on the aerobic and anaerobic biological fixed-
film fluidized bed (Oxitron/Anitron) and membrane suspended
growth biological reactors (MARS). Physical-chemical mechan-
isms for contaminant removal are an inherent part of the systems
or can be readily integrated into the systems.
The Oxitron/Anitron and MARS systems overcome many con-
cerns in applying microbial methods for treatment of hazardous
wastewaters. The systems: provide high volumetric efficiency and
maximum opportunity for treatment of slowly biodegradable or
recalcitrant compounds; can withstand microbially toxic/inhibi-
tory feed inputs; allow treatment of volatile organics with little or
no stripping; and result in the production of minimal residual by-
products (excess biomass or other residuals). Examples of com-
plex organics treatable in one or more of the systems include
toluene, methyl ethyl ketone, naphthalene, trichloroethylene and
pentachlorophenol. To date, mobile/transportable and per-
manently installed Oxitron/Anitron and MARS systems have
been applied for treatment of a variety of toxic organic and in-
organic compounds.
REFERENCES
1. Sutton, P.M., Kothari, D., Mishra, P.N. and Hachigian, L., "Bio-
logical Treatment of Metalworking Fluids: A New Application for
Fluidized Bed Technology," presented at the WPCF Conference,
Kansas City, MO, 1985.
LEACHATE FATE & CONTROL 257
-------
Horizontal Drilling Beneath Superfund Sites
Wade Dickinson
R. Wayne Dickinson
Petrolphysics, Ltd.
San Francisco, California
Thomas W. Crosby
Harlan N. Head, Ph.D.
Bechtel National, Inc.
San Francisco, California
ABSTRACT
As a result of new drilling techniques, horizontal radial wells
can now be remotely placed from a central vertical well. This new
technology potentially has numerous applications to hazardous
waste problems. This paper describes the methods by which such
horizontal wells (radials) are emplaced and discusses potential
applications in remediation and monitoring of hazardous waste
sites.
Current conventional methods for groundwater control rely on
placement of numerous vertical drill holes and wells for the char-
acterization, monitoring and remedial action phases of site stud-
ies. There are limitations and inherent difficulties with vertical
wells, such as surface access and potential cross-contamination of
aquifers. Horizontal well placement techniques may provide vi-
able solutions to these limitations.
INTRODUCTION
Horizontal wells have been used for decades in a limited way.
Traditional horizontal well drilling methods include hillside
drains and collector radials from large diameter wells. These
methods are either limited in application by terrain or require
human miner access downhole. In the oil industry, deviated drill-
ing from the vertical to the horizontal is available with large
radius of curvature (1800 to 3000 ft) or with medium radius of
curvature (20 to 40 ft). Two major limitations of large and med-
ium radius deviated drilling are that: (1) only one radial may be
placed in each vertical well, and (2) the horizontal wells cannot be
placed at a precise level. Such precise placement requires curva-
ture from vertical to horizontal via a small radius turn. The recent
development and commercialization of a novel high pressure,
hydraulic jet drilling system by Petrolphysics and Bechtel now
allows the placement of multiple horizontal radials or wells at a
small, very sharp 12-in. radius of curvature from a central vertical
well. With this new system, horizontal radials can be placed at any
depth radiating from a 5.5-in. or larger diameter vertical casing.
Several stacked layers of radials can be placed from the same ver-
tical well.
Placement of horizontal radials into a contaminated aquifer
from a conventional vertical well can provide marked enhance-
ment of access to the formation. Because most aquifers are near
horizontal, the placement of wells in the plane of the aquifer
should increase the collection/injection area of a well, as com-
pared to placement of vertical wells across the aquifer. With that
intrinsic geometric advantage, the volume of formation that can
be serviced by a well is markedly increased. Hence, fewer vertical
wells need to be drilled, and a more uniform access to the con-
taminated aquifer is provided.
This paper first will describe the short radius horizontal radial
drilling system and associated well completion methods. Applica-
tion of this horizontal technology to hazardous waste site prob-
lems then will be discussed.
HORIZONTAL RADIAL DRILLING SYSTEM
Over the past 6 years, Bechtel Group and Petrolphysics Ltd.
have been developing a completely new technology of placing and
completing horizontal drain holes or radials. That technology was
developed primarily for enhanced recovery of both heavy and
light oil in both shallow and deep oil reservoirs.
The Petrolphysics/Bechtel radial system consists of a pattern of
radials radiating from a central vertical well. Several such pat-
terns can be spaced vertically at different depths in a single well.
These radials extend into the formation for distances up to several
hundred feet (Fig. 1). To place the radials an erectable whipstock
is lowered downhole into a previously underreamed cavity. The
whipstock is loaded with a long 1.25-in. diameter steel contin-
uous tube which has a hydraulic drill head welded to its nose.
High pressure water drilling fluid is pumped through the steel tub-
ing. The hydrodynamic forces on the drill head pull 1.25-in.
tubing through the whipstock, making a 90° turn at a very short
12-in. radius. The tube then moves horizontally into the forma-
tion.
Several radials may be placed at a specific horizon to allow in-
jection or drainage from contaminated hydrogeologic units. Each
radial is completed in situ by electrolytic perforation of the tub-
ing and by placement of a gravel pack within the radial well bore
around the steel tube.
HELD RESULTS AND COST OF RADIAL
PLACEMENT
Over 27,000 ft of 1.25-in. diameter horizontal radials have been
placed during development and commercial production opera-
tions. These radials have been placed at various depths from near-
surface down to 6,800 ft in several parts of the United States and
in Canada. As shown in Fig. 2, multiple radials can be placed at
the same depth, and patterns of radials can be placed at multiple
levels from a single vertical well. As many as 100 radials have been
placed in a single well at three different levels.
The drilling is done hydrodynamically, and the radial is pulled
into the formation by its own hydrodynamic force (Rabbit Force)
which always keeps it in tension. Hence, the radial naturally tends
to go horizontal and straight. A wide variety of geologic forma-
tions from unconsolidated formations to beds of granite cobbles
have been successfully penetrated.
In the oil industry, the total cost of radial placement in deep oil
reservoirs is about $135,000 for four 1.25-in. radials of 100- to
200-ft length. This cost includes the deep drilling rig, tubing
258 LEACHATE FATE & CONTROL
-------
CABLE
RESTRAINT TRUCK
RIG
HIGH PRESSURE
TUBING STRING
CABLE RESTRAINT
1-1/4 INCH STEEL
DRILL STRING
FORMATION
UNDERREAMED
ZONE
CASING
HIGH PRESSURE SEAL
RADIAL BORE
INTO FORMATION
HYDRAULIC ERECTION
CYLINDER
Figure 1
Overall Drilling System
strings, pumps and all services including logging. The incremen-
tal cost of placing more than four radials is small because the
placement time per radial is very short. For shallow applications
of radials such as Superfund sites, these radial placement costs
should be reduced by 50% or more both because of a lesser equip-
ment requirement and a substantially lesser time requirement.
DRILLING SYSTEM DESIGN
Drilling and Drill String Propulsion
Drilling of the formation and propulsion of the drill both use
the same hydrodynamic force. This force concurrently pulls and
pushes forward the radial tube or drill string. The force both digs
the bore hole and pulls the string into that hole; hence, it is called
the Rabbit Force.
In drilling, the drill string begins vertically, proceeds around a
90° whipstock turn and then enters and rapidly penetrates a for-
mation horizontally. Typical velocities are 5 to 120 ft/min in un-
consolidated formations. The same fluid pressure forces are
further applied to control the vertical movement of the drill string
while drilling. The overall drilling system configuration is shown
in Fig. 1.
Pulling and Pushing Force
The 1.25-in. drill string is vertical and contained in a sealed
chamber made up of a working string of larger diameter drill pipe
from the surface down to the whipstock. The 1.25-in. drill string
is placed within the larger working string and thence passes
through a fixed high pressure chevron seal in the top of the whip-
stock.
.CENTRAL VERTICAL WELL
RADIAL
FOUR RADIAL PLAN VIEW
\
TWELVE RADIAL PLAN VIEW
Figure 2
Well Radial Patterns
The high pressure drilling fluid, usually water at 8,000 to 10,000
Ib/in.2, creates a pulling force (Rabbit Force) on the nose of the
string. This pulling force keeps the string in tension so that it
tends to go straight. The same fluid pressure exerts a pushing
force on the cross-section of the posterior of the drill string. This
pushing force helps push it through the seal/whipstock system.
For example, at 10,000 Ib/in.2 pressure in a 1-in. ID tube, the net
pulling force is about 8,000 Ib. A pushing force of about 3,500 Ib
is exerted on the posterior of a typical 1.25-in. tube. The com-
bined result is a total push/pull forward force on a 1.25-in. tube
of approximately 11,500 Ib.
Whipstock
The next major component of the system is the whipstock
shown in Fig. 3. The whipstock is lowered on the end of a larger
diameter working string. It is then erected downhole in a prev-
iously underreamed zone. The whipstock contains a set of slides
and wheels that enable the 1.25-in. steel drill string to move con-
tinuously and rapidly from the vertical, around the 90° whip-
stock turn, through the exit section or straightener and thence out
horizontally into the formation.
LEACHATE FATE & CONTROL 259
-------
HIGH PRESSURE
TUBING STRING
ENTRY SECTION
(INITIATES 90' CURVE)
WHIPSTOCK BODY
1-1/4 INCH STEEL
DRILL STRING
EXIT SECTION
(STRAIGHTENER)
HYDRAULIC ERECTION
CYLINDER
Figure 3
Mark I Whipstock
EXCITATION
I SOURCE
,TOOL
ELECTRICAL SCHEMATIC
- SLIDE WIRE
FLEXIBLE VERTEBRAE CABLE
SKIN BACKBONE
VERTEBRAE
FLEXIBLE
N /
SEPARATOR LINEAR VOLTAGE
SPRINGS DIFFERENTIAL
TRANSFORMER
CABLE BACKBONE
SLIDE WIRE
TOOL CROSS SECTION
Figure 4
Model V, Radius of Curvature Tool
UHCOWOUWH
Figure 5
Spinning Jei in Unconsolidated Formation
VERTICAL WELL
/ SLOTTED UNEB
- UNDERflEAMED ZONE
RADIAL BORE LENGTH
GRAVEL PACK
-.--V:-/-"r:¥P:^ip«!
' -', -• --V*v^fc?J
viW
~
TAa. PERFORATED NOSE
FttJER HORIZONTAL FILTER
WELL
DRU.HEAO
PERFORATION
Figure 6
Radial Well Completion with Perforations
Because the drill string is triaxally stressed during this process
(hoop stress plus axial stress plus bending stress), the deforma-
tion of the 1.23-in. string at a 12-in. radius can be accomplished
at low incremental stress. In effect, the 1.25-in. tube is in a tran-
sient plastic state. Many radials can be placed with the same whip-
stock at the same level and at several different azimuths without
tripping that whipstock uphole. If desired, the whipstock can be
used to place stacked layers of radials in the same vertical well.
Radial Restraint and Control System
Some real-time control of radial pitch or inclination can be
achieved by controlling the drill string velocity as it moves
through the formation. To provide that control of velocity, es-
pecially during progress through the whipstock and during initial
entry into the formation, a cable restraint is applied. As s00*™.1?
Fig. 1, this consists of a cable restraint truck and a wellhead lugfl
pressure grease seal at the surface. A connecting cable runs down
to a removable disconnect at a tail of the 1.25-in. drill string. Ttos
disconnect is removed after a run to permit the entry of wire line
logging tools. The restraining cable instrumentation gives a real-
time indication of both the extent and rate of drill string move-
An alternate restraint system to keep the radial from moving
too fast uses a hydraulic tail which is constructed much wee a
double acting shock absorber so that the radial is restrained ana
its velocity is controlled by a closed fluid system. This eliminates
any cable connection to the 1.25-in. radial.
Electrical Downhole Logging V.WMO
Following the placement of a radial, it is usually desirame i
precisely locate the radial bore hole in three dimensional space. *
260 LEACHATE FATE & CONTROL
-------
WATER
SURFACE
Figure 7A
Conventional Vertical Well Field
L WATER
SURFACE
RADIAL WELL
Figure 7B
Well Field with Vertical Well and Horizontal Radials
EXISTING
DISPOSAL
TRENCH
Vertical Well System in Fractured Media
' Figure 8
Leachate Monitoring or Collection by Horizontal Radials
Horizontal Radial System in Fractured Media
Figure 9
highly flexible directional wireline logging system, the Model V
Radius of Curvature Tool, has been developed and commercial-
ized for this purpose.
The Model V Tool, shown in Fig. 4, can be pumped down the
90° whipstock turn within a 1-in. ID tube to yield three dimen-
sional data on the radial trajectory. The tool yields vertical and
horizontal location; the length of the wire line cable yields the
length of trajectory.
Model V is built around a flexible backbone with small mov-
able slide wires placed at 90° to each other. Differential move-
ments of these slide wires on the inner and outer radius when the
tool is bent within the 1.25-in. drill string result in electrical sig-
nals that provide a reproducible indication of curvature of the
drill string down which the tool has been pumped. The tool also
can function under several thousand psi hydrostatic pressure.
Model V can locate and print out the location of the 1.25-in.
radial with reproducible accuracy of better than 99%. This tool is
commercially operational.
Spinning Jet Drill Heads
A major improvement in fluid jet drill heads, the Spinning Jet,
has been developed (Fig. 5). These drill heads in general produce
a thin, conical shell of water which, in turn, is believed to create a
toroidal slurry body of cuttings; this toroidal body would be
shaped like an inflated inner tube. These cuttings appear to act as
a rotating body of abrasive slurry because this drill head cuts both
hard crystalline rocks and consolidated sedimentary formations.
In effect, the cuttings are the cutter. The technology also is applic-
able to other down hole processes such as underreaming.
LEACHATE FATE & CONTROL 261
-------
With the Spinning Jet drill head, it is possible to cut unconsoli-
dated formation at 5 to 120 ft/min. The resulting bore hole diam-
eter may be selected and varied from 4 to 24 in. by controlling the
internal angle of the conical shell of water particles.
For harder materials analogous to Berea sandstones, the pene-
tration rate for a 4- to 6-in. bore hole is several in./min. For hard
granite rocks, the penetration rate is one or more in./min. The
Spinning Jet drill head applied to an unconsolidated formation is
shown in Fig. 5.
RADIAL WELL COMPLETION METHODS
Once the radial tubing is in place in the formation and its loca-
tion is logged, the well can be completed by perforating the radial^
gravel packing and placing the flexible slotted liner. These meth-
ods have been demonstrated in the laboratory on 80-ft full-scale
radials.
Gravel packing of the annular space between the radial bore
and the steel radial tube is conducted with a two-step, bi-direc-
tional process which provides a 100% fill of consolidated gravel.
The gravel is placed in a slurry using water as a transport medium.
To allow fluid infiltration from the formation into the radial,
the 1.25-in. radial tube can be perforated in situ by an electroly-
tic perforator tool. Over 120 perforations can be made simultan-
eously. The perforations are round, sharp-edged orifices, and
perforation size can be controlled from the surface while the per-
forating process is underway.
A flexible slotted liner then can be placed within the perforated
radial to keep gravel or formation sand from entering the well
perforations. Flexible liner permeability can be selected over a
wide range to preclude any formation fines from being carried
into the radial by the fluids.
Wire brush filters then are placed at the ends of the radial to
prevent gravel pack gravel from entering into the slotted radial.
The total radial well completion system is shown in Pig. 6.
The final well construction therefore consists of an array of
horizontal wells which can extend laterally up to 200 ft from the
central vertical well. The location of each horizontal well bore is
defined from the electronic downhole logging. The radial bores
are gravel packed, and the steel radial tube is perforated and lined
to prevent migration of the gravel pack or formation fines into
the 1.25-in. radial tube. These radial tubes are terminated in the
underreamed zone of the vertical well. A standard submersible
pump and a vertical slotted liner then can be placed in that central
vertical well.
APPLICATION OF HORIZONTAL WELLS
TO WASTE PROBLEMS
There are several potential applications of horizontal well
methods to hazardous waste problems. The most obvious poten-
tial applications include groundwater control and in situ modifi-
cation. The benefits of horizontal drilling arise primarily from
the ability to intercept horizontal groundwater and geologic struc-
tures. Thus contaminant plumes may be penetrated laterally
rather than vertically.
Groundwater Control
The typical well field treatment scheme consists of several ver-
tical wells laid out in an array which intercepts and withdraws
the contaminated plume for treatment (Fig. 7A). The design of
the well field is dependent on site specific parameters such as
aquifer transmissivity, plume geometry, groundwater character-
istics, contaminant characteristics and surface restrictions. Sur-
face restrictions include power or process plants, office and in-
dustrial buildings, suburban developments, streets, highways and
powerline corridors. Natural surface restrictions, such as water
bodies, also may restrict well field construction.
Vertical wells draw water in all directions within the cone of
depression as shown in Fig. 7A. Large amounts of water are
drawn in from the plume area as well as some clean groundwater.
The mixed groundwater is collected by a header system for treat-
ment. Thus potentially large volumes of water for treatment may
be generated.
A horizontal radial well system shown in Fig. 7B could help to
overcome the typical problems shown in Fig. 7A. As shown in
Fig. 7B, a limited number of central vertical wells can be strateg-
ically placed to deploy horizontal radial wells within the contam-
inant plume area. The radials can be placed beneath existing sur-
face facilities without disruption. The horizontal radial well sys-
tem thus reduces the number of vertical wells, the footage of drill-
ing and the number of screens and pumps.
Aquifers with low transmissivity require a larger number of
conventional wells since they need to be placed on closer spacing.
Hence well field operating costs are high in contaminated aquifers
of low transmissivity due to the long operational period for ex-
traction and treatment. The alternative of using horizontal collec-
tor radials could provide significant cost savings by requiring few-
er wells and providing lower operating costs.
Subsurface Drains—Leachate Interception
The horizontal radial system allows the placement of radials
directly beneath existing surface and shallow burial waste facili-
ties (Fig. 8). The horizontal radials allow the interception of
leachate from disposal trenches prior to migration and mixing
with groundwater.
Placing perforated horizontal radials in the unsaturated zone
beneath the disposal trench or tank also could allow the deploy-
ment of leachate detection equipment such as vapor monitors.
Leachate detection monitors could possibly be designed to func-
tion on a perforation by perforation basis within the radial to give
contaminant concentration gradient data along the radial.
In disposal areas where the migration of leachate is primarily
via vertical fracture flow, a perimeter horizontal radial array
would intercept vertical and steeply inclined fractures. The perim-
eter array allows detection and monitoring in the unsaturated
vadose zone. In the saturated section, monitoring is supplemented
by the ability to pump and treat leachate prior to migration off-
site. A horizontal monitoring array thus has obvious significant
advantages over the conventional vertical monitoring well system,
since effective monitoring is dependent on interception of vertical
fractures (Fig. 8). Horizontal radials will intercept such fractures
much more effectively than vertical wells. The effectiveness of in-
tercepting vertical fractures with horizontal radials for improved
oil production already has been successfully demonstrated com-
mercially.
Injection Wells
Similar advantages exist when using horizontal radials to inject
groundwater to change flow and gradient or to discharge treated
groundwater. The injection can occur along a horizontal line
across the aquifer, which significantly reduces the number of ver-
tical wells typically required.
In Situ Modification
The horizontal drilling system has the unique ability to pene-
trate contaminated soil and groundwater plumes in a horizontal
plane regardless of the depth below ground surface. The horizon-
tal radial can be utilized for a wide variety of in situ treatment
methods: (1) injection of acids for neutralization, absorbing clays
or reactive chemicals, (2) injection of micro-organisms and nu-
trients and (3) physical modification by freezing or grouting. The
latter two methods are of particular interest.
262 LEACHATE FATE & CONTROL
-------
Bioremediation is a developing method for in situ treatment of
certain petroleum products and volatile organic compounds.
These contaminants often occur as horizontal lenses within the
soil or floating along the water table surface. The introduction
of microorganisms and nutrients along a horizontal line or radial
array within the contaminant lense would allow rapid in situ de-
gradation.
In situ modification by solidification/stabilization can be
effected by binding waste within a solid mass. Solidification can
be accomplished through grout injection (cement or polymer) and
through freezing by continuous circulation of a refrigerant or
injection of a cryogenic liquid. Conventional grout injection con-
sists of an array of numerous vertical holes through which cement
or a chemical grout is injected under pressure. The grout perme-
ates the pores and the fractures in the formation prior to solidifi-
cation at its set time. In situ freezing is accomplished through in-
jection of cryogenic fluids (nitrogen, liquid nitrogen or liquid
carbon dioxide) through a well and header of concentric pipe sys-
tem. Horizontal wells placed in a contaminated aquifer or ortho-
gonal to vertical fracture sets would allow a more effective means
of in situ solidification.
As shown in Fig. 7B, in some emergency applications radials
could be placed remotely and rapidly as after a catastrophic acci-
dent at a nuclear or chemical plant. Such a procedure possibly
could have been applied to a situation such as Chernobyl in the
USSR to provide grouting beneath the failed reactor without re-
quiring personnel to be near or under the reactor.
CONCLUSIONS
The application of horizontal radial well methods to waste
problems offers another subsurface dimension to contaminant
collection, monitoring, treatment or immobilization both in un-
saturated and saturated materials. Such radials can be placed
around the periphery or beneath a waste disposal site where they
can monitor leakage or collect leaked fluids.
For permanent immobilization, radials offer the opportunity to
grout along horizontal injection holes. For temporary stabiliza-
tion, injection of cryogenic fluids along radials could effectively
freeze a plume in place. In emergency situations, radials could be
placed very rapidly beneath a failed and leaking plant to provide
grouting to isolate potential leakage into the groundwater.
Many radials can be placed from a single vertical well. These
radials can be placed in one horizontal plane or in several layers
stacked above each other. The total radial placement operation is
done very rapidly.
ACKNOWLEDGEMENTS
The authors gratefully thank the Bechtel Group Inc., Bechtel
Investments Inc. and all of their colleagues for their support and
encouragement of this work.
REFERENCES
1. Dickinson, W. and Dickinson, R.W., "Horizontal Radial Drilling
System," SPE 13949, Proc. of Society of Petroleum Engineers (SPE)
1985 California Regional Meeting, Bakersfield, CA, Mar. 1985.
2. Dickinson, W., Anderson, R.R. and Dickinson, R.W., "A Second-
Generation Horizontal Drilling System," IADC/SPE 14804, Proc. of
1986IADC/SPEDrilling Conference, Dallas, TX, 1986.
LEACHATE FATE & CONTROL 263
-------
Performance Evaluation of
Cement-Bentonite Slurry Wall Mix Design
Christopher R. Ryan
Steven R. Day
Geo-Con, Inc.
Pittsburgh, Pennsylvania
ABSTRACT
A cement-bentonile slurry cut-off wall is a variation of the slurry
wall process that is used to create an underground barrier (o stop
the lateral flow of groundwater and other fluids. Because of the
relative simplicity of the construction process, the cement-bentonile
technique might be chosen over other types of slurry cut-off walls
in situations with poor across or poor subsoil conditions. The
characteristics and engineering properties of cement bentonite are
generally not well understood and are poorly documented. This
paper documents a case study where enough testing was done to
draw significant conclusions.
The principal findings of this study were the moderate increase
in strength and decrease in permeability which result when fly ash
is added to cement-bentonite. In addition, sampling and testing
techniques were found to have little effect on the cement-bentonite
permeability. Due to the complexity of the cement-bentonile scaling
mechanism, only long term permeability tests were appropriate to
evaluate cement-bentonite permeability.
INTRODUCTION
Slurry cut-off walls have been used in the United States for about
40 years to control the lateral migration of groundwater and other
fluids. The slurry wall system uses bentonite slurry (similar to
drilling mud) to facilitate the excavation of a vertical-walled slot
or trench into the ground. This slot subsequently is backfilled with
various materials, depending on the application.
The most popular type of cut-off wall is the soil-bentonite (SB)
variety where the trench is back Tilled with a blended mass of soil
and benlonite. At least 90
-------
There are several disadvantages to the CB technique, however, that have
led to its limited use when compared to the SB technique:
• Due to the addition of cement to the backfill blend, the cost of CB will
be more than a comparable SB project unless one of the technical ad-
vantages listed above presents a significant economic benefit.
• CB mixes, in most cases, yield permeabilities in the range of 1(T6
cm/sec, whereas SB usually can be mixed to provide
permeabilities in the range of 10'7 - 1 (Hem/sec.
• Because of the high water content of the set mix and the relative
susceptibility of both cement and bentonite to various types of
degradation by waterborne contaminates, CB walls are not
always the best choice for sites that have contaminated ground-
water. Leachate compatibility tests may be run to confirm this
on a case by case basis.
APPLICATIONS
The CB technique was developed in Europe in the late 1960s and
continues to be used there almost exclusively instead of soil-
bentonite. The first application in the United States was in 1973
for a cut-off under a dam in the southeast. Since that time, there
have been many projects, some quite large. Perhaps the most
dramatic was the work done at Braidwood Nuclear Power Station
in the mid 1970s. The plant site was dewatered by 1 -mile long, 30-ft
deep CB wall. Subsequently, the cooling lake for the plant was
isolated by miles of slurry wall up to 120 ft deep.
Since the early projects, a better understanding of CB proper-
ties and advantages has begun to evolve; now most applications
are more appropriately engineered. There had been, for example,
the notion that CB is "stronger" and more resistant to loads than
SB. In fact, the opposite can be true. CB generally is stronger in
unconfined compression tests, but SB usually is stronger and less
compressive when consolidated and tested under triaxial conditions.
The result of the new understanding of CB has been a more appro-
priate use of the product.
Currently, the most typical applications are those where difficult
access is involved (Figure 4) and the CB represents an economic
advantage over SB by eliminating the backfill mixing operation.
Samples are (1) situations where the cut-off wall passes through
plant sites with buildings close by and (2) along the narrow tops
of containment dikes. There have not been many environmental
applications for the reasons stated earlier. The major exception
is tank farm containments for underground spills of petroleum pro-
ducts (Figure 5). Oil and gas usually have no deleterious effect on
theCB material, and the tough access conditions around most tank
farms make the CB method economically attractive. Sometimes
it is possible to key the wall into the lowest seasonal water table
and literally skim the floating product off the groundwater surface.
Figure 4
CB Work in Area of Tight Access
STORAGE TANKS
...7 ?. ^?..f..f 7 >
OILY WASTES SEEP DOWN'
TO THE WATER TABLE
GROUNDWATER
TABLE
BEFORE CONTAINMENT
I I
SUMP TO
COLLECT OIL
CEMENT-BENTONITE
CUT-OFF WALL
Figure 3
Set-up CCB Slurry
AFTER CONTAINMENT
Figure 5
Schematic of Typical Application
Oil-Polluted Groundwater
It is worth noting that the first Superfund project ever carried
out (Stroudsburg, Pennsylvania) used a CB wall for containment.
In retrospect, this application may have been somewhat inap-
propriate; all subsequent superfund slurry wall containments have
used the SB technique.
MIXED DESIGN CONSIDERATIONS
The determination of appropriate ingredients for cement-
bentonite requires a knowledge of the material properties and their
interactions and an understanding of mixing technology. An appre-
ciation of slurry workability, recognition of project specifics and
experience must be added to this list. Most knowledge about CB
comes from previous experience, much of it with proprietary
mixtures and mixing techniques.
The basic component of cement-bentonite slurry is the bentonite-
water mixture. Specifically engineered cement-bentonites generally
are created by changing the cement content or by adding other in-
gredients to the bentonite-water slurry.
BARRIER TECHNOLOGY 265
-------
The final properties of cement-bentonite are a function of the
initial mix proportions, curing time, soil conditions and sampling
and testing methods. Some commonly specified mix proportions
are given in Table 1. More exotic mixtures may contain fly ash
and set retarders. In general, cement-bentonite mixtures for slurry
trenching are specified by performance criteria.
The performance limits of cement-bentonite are defined by the
following major restraints:
• The slurry must be pumpable and allow excavating equipment
to penetrate it easily for extended periods. High cement and/or
bentonite proportions and fly ash can increase slurry viscosity;
set retarders can decrease viscosity.
• The slurry must set within a definable period. Too little cement
or too much fly ash can impede the set. Set retarders may ex-
tend the fluid state, although unpredictably.
• The slurry properties must be controllable and regular within
limits. Fly ash is generally of irregular quality and may adversely
affect slurry viscosity without the use of set retarders.
• A continuous, low permeability barrier must result. Too little
bentonite can result in higher than expected permeabilities. A
higher solids content generally leads to lower permeabilities.
• The set slurry should be strong enough to resist hydraulic and
earth pressures, yet flexible enough to resist cracking and earth
movements. Too much cement or fly ash can result in a material
which is stronger, yet subject to brittle failure at low strains.
The mixture of materials used in cement-bentonite slurries is
known to meet the above criteria depending upon mix proportions.
Any significant change in the proportion of one ingredient can
affect the entire mixture in ways which may make the product
unusable either in the liquid or solid state.
SAMPLING AND TESTING TECHNIQUES
During a recent project in southern California, three separate
design mixtures were used to construct five cement-bentonite
groundwater barriers. Four well-known independent testing
laboratories were employed to perform various tests on the field-
mixed cement bentonite. Samples of the cement-bentonite were ob-
tained from the trench while still fluid. Other samples were cored
from the set-up wall using thin tube samplers months after con-
struction. Over 100 permeability measurements were made and IS
unconflned compression tests were performed.
AMPLES TESTED BY FALLING HE
(em /IK)
5i 3'
« a
ACCELERATED CURED S
K,
»^
^/
'
/
f
r
S
f
£
7
- • • •
•
•
X
-^j-
f
/
^
/
^
2
2
•
K*
2
«•
K, (cm/we)
NATURALLY CURED SAMPLES TESTED BY CONSTANT HEAD METHOD
Figure 6
Influence of Curing and Testing Conditions
On the Permeability of Cement-Bentonite Samples
Fluid samples of cement-bentonite slurry were gathered from
the mid-depth of the trench when each panel was completed. The
still-fluid samples were poured into 3-in. diameter plastic tubes of
two lengths, 1 ft and 3 ft. The samples were capped, sealed and
allowed to set undisturbed on-site for 3 days in a climate-controlled
construction trailer.
Due to the long time lapse between construction and final cure,
it may be desirable to somehow artificially accelerate the cure of
the slurry in order to monitor performance of the installation. Some
of the 1-ft samples were artificially cured in a water bath (at 140°F)
for 5 days. The samples were extruded, trimmed to a workable
length and tested in a triaxial permeability apparatus for 3 days
including time for consolidation. The 3-ft samples were allowed
to cure at room temperature for at least 28 days and were tested
in a triaxial permeability apparatus for a period of 7 to 8 weeks.
A comparison of the results is presented in Figure 6. The quick
cure method did not produce an acceptable agreement with the
naturally cured samples. The average ratio of permeability of the
artificially cured samples to the naturally cured samples is about
5. This discrepancy could be due to other factors beyond cure con-
ditions. In order to ascertain the source of this discrepancy, a com-
parison was made to evaluate the effect of the sampling and testing
techniques on permeability.
The results of the comparison between the different sampling
techniques are shown in Figure 7. No obvious or persistent dif-
ferences are evident; however, there is a slight tendency for the
undisturbed samples to give slightly lower permeabilities. In situ
cure conditions, consolidation stresses and water loss through the
trench walls may have contributed to this trend.
CM ADOT LOM 1UK
TWW HIT UOM TOUt •
1
i
1-5
t-4
SAMPLE NUMBER
Figure 7
Permeability Results from Various Sampling Techniques
(All Samples Cured at Least 30 Days)
A separate comparison was made to evaluate various testing
parameters on cement-bentonite permeability. The factors
evaluated were sample size, permeant, test method and consoli-
dation stress. The results are presented in Figure 8. Again, testing
effects are rather insignificant, with increased consolidation
pressures giving the most noticeable effect.
DESIGN MIX PERFORMANCE
Unconfined compressive strength tests were performed to
evaluate the strength of the three cement-bentonite mixtures. The
results of these tests are presented in Figure 9 along with design
curves from previous work by others. In all cases, the strengths
were somewhat higher than expected. We assume that this was due
to higher than normal water loss from the slurry into the trench
walls. The slurry walls were constructed in essentially dry ground,
well above any permanent groundwater level. The dry ground per-
mitted some of the free liquid to pass out of the slurry Witt a
resulting increase in solids accumulated in the trench and, thus,
266 BARRIER TECHNOLOGY
-------
DEMNENALIZEO WATER
OHOUNDWATM
TAP WATER
C/W FA/C
MIX I 0.20 O.OO
MIX 2 0.20 O.Z4
MIX 3 0.25 0.60
SAMPLE SIZE
SAMPLE I SAMPLE t
SHORT TERM INFLUENCE OF PERMEANT
LEflEHO
| FALLING HEAD
Q CONSTANT HEAD
I
§4
SAMPLE I SAMPLE •
TEST METHOD
SAMPLE 1-3 SAMPLE !-4
AVERAGE EFFECTIVE CONFINING STRESS
Figure 8
Permeability Results Using Various Testing Techniques
(All Values of Hydraulic Conductivity Obtained After 3-5 Days of Flow)
FLY ASH TO CEMENT RATIO FA/C
0
3
80
60
40
?0
90,90,90,
17,9''
90
9O
|
90 .
90 '
/ <
/ ;
/ /'
/
/ i
90-5P ,
42(tOSptl)
28 DAYS*
9O
62 .
7 DAYS
32
1.15
Unconfined Compressive Strength (psi) >5
Strain at Failure (<7o) > 15
Hydraulic Conductivity (cm/sec) sSxlCT
Curing Time (days) >28
BARRIER TECHNOLOGY 267
-------
CONCLUSIONS • The addition of fly ash to cement-bentonite was shown to
Artificially accelerating the cure of cement-bentonite leads to scrved durin* lon*-tcrm PcrmeabilitV tests-
conservative permeability test results.
Cement-bentonite is relatively insensitive to laboratory test Additional research and more documented case studies are
conditions. Effective confining stress is the most important needed to help the engineering community fully understand cement-
variable investigated. bentonite mixes.
268 BARRIER TECHNOLOGY
-------
Geomembrane Uses with Hazardous Wastes
John D. VanderVoort
Poly-America, Inc.
Grand Prairie, Texas
ABSTRACT
This paper discusses the use of geomembranes with hazardous
wastes. It concentrates mainly on polyethylene geomembrane
which is the predominant material being used because of its super-
ior strength and chemical resistance properties. This paper in-
cludes sections on manufacturing, quality control, failure modes,
seaming methods and monitoring.
INTRODUCTION
The first synthetic materials began to appear as liners for use in
water retention ponds and canals in the 1940s. In the early days,
butyl rubber was the most commonly used material. As the devel-
opment of polymers and the need for synthetic liners increased,
more base materials were commonly used for liners. Today, the
most common base materials used as liners are:
• Butyl Rubber
• Chlorinated Polyethylene
• Chlorosulfonated Polyethylene
• Ethylene Propylene Diene Monomer
• Polyethylene
• Polyvinyl Chloride
In the beginning, liners were referred to as Flexible Membrane
Liners. Later, because liners did not show immediate permeation
to liquid, they were called Impermeable Barriers. Today, syn-
thetics are being referred to as Geomembranes. Applications
have expanded from canals and water retention ponds to many
other uses. Included among these uses are curtain walls, floating
covers, landfill caps, renovations, tunnels and underground
storage.
Recently, geomembranes have become more popular because
of new regulations where they can be one of the least costly alter-
natives for hazardous waste containment. Because hazardous
wastes, in most cases, contain organics (particularly aromatics)
the predominant material being considered for containment is
polyethylene due to its overall superior chemical resistance. An-
other problem with many hazardous waste containment appli-
cations is that the exact compositions and concentrations of the
wastes are unknown. Another reason polyethylene is the pre-
dominant geomembrane in hazardous waste containment is that
many of these applications contain solids, etc., and polyethy-
lene's superior strength properties become advantageous.
POLYETHYLENE
Polyethylenes generally are classified into one of three cate-
gories described below.
Low Density Polyethylene (LDPE)
LDPE is produced by high pressure polymerization yeilding a
non-linear chain. LDPE is not commonly used as a geomem-
brane since the other polyethylene materials have improved
strength and chemical resistance properties.
High Density Polyethylene (HDPE)
HDPE is produced with low pressure polymerization yielding
a linear chain. Materials produced by this process generally are
used as liners only when the material density is below 0.942, as
higher densities would be too stiff and would not pass the stress
crack test. HDPE geomembrane materials are, in fact, HDPE
copolymers where the copolymers are 1-hexane or 1-butene which
is used to obtain side branching and reduce density.
Linear Low Density Polyethylene (LLDPE)
LLDPE is produced with low pressure polymerization yield-
ing a linear chain but lower density. LLDPE is the newest mem-
ber of the polyethylene family. With its lower crystalline nature,
LLDPE gives the polymer added flexibility with a molecular
weight for chemical resistance. There are LLDPE materials that
demonstrate superior ultimate tensile, tear and puncture resis-
tance over the common HDPE liners.
MANUFACTURING
Polyethylene geomembranes typically are manufactured by two
processes.
Sheet Extrusion
In the sheet extrusion process, the molten plastic is forced
through a die under pressure to form the final sheet thickness re-
quired. This process lends itself to sheet thicknesses in excess of
20 mils. Sheet widths of up to 12 ft are produced in standard sheet
lines, and specialized processes have been developed to produce
greater widths.
Blown Film Extrusion
In the blown film extrusion process, molten plastic is ex-
truded through a tubular die in a vertical direction. Air is blown
through the die to form a bubble. The bubble is cooled, col-
lapsed/flattened at the top of its travel and then passed through
a wind-up system. This process lends itself to making extremely
thin gauges (even below 1 mil) to thicknesses over 100 mils. Com-
mon widths exceed 20 ft.
MANUFACTURING QUALITY
It is important to ensure the use of good quality control pro-
cedures in manufacturing. Because polymer manufacturing is a
controlled process in an enclosed environment, there are min-
imal problems arising from the original producer. However, it is
imperative to keep good records. These records should include
all materials, operating conditions and samples of not only the
BARRIER TECHNOLOGY 269
-------
finished product but also all basic raw materials. The most im-
portant recorded physical properties of a polyethylene sheet are:
• Thickness
• Continuity
• Tensile Properties
• Tear
• Puncture
• Stress Crack Resistance
• Density
• Percent Carbon Black
• Melt Index
FAILURE MODES
An application engineer should understand the potential causes
of failure in the initial selection process. Polyethylene, like all
synthetic materials, has its limitations. The more information
one has about the intended application of the material and the
ability to relate this future use to the geomembrane, the more
one can reduce the chance for failure. The most common sources
of failure are described briefly below.
Weatberability
Weatherability studies should include verification of the
temperature extremes as well as the ultraviolet resistance of the
polyethylene. Generally, polyethylenes have a constant use
temperature range from -70°C. to +90°C. At high tempera-
tures this could be affected by chemicals; whenever liquid temp-
eratures above 70°C. are expected, verification tests should be
run. Polyethylene is well known for its ability to withstand sun-
light if properly compounded with carbon black. The ability to
withstand UV relates to concentration, type and dispersion of
carbon black in the polymer. Generally, the specification should
include a 2.0'% minimum carbon black of an ASTM N550 grade
or better and a dispersion rating by ASTM D3015 of Al.
Chemical Resistance
The primary purpose of a liner is to protect the groundwater
from contamination. Thus the liner must be resistant to the chem-
icals it is expected to contain. It is advisable to test the material
against the worst case temperature and contaminant concentra-
tion expected. Unfortunately, there are many areas which make
chemical compatibility projections difficult. Among these are:
• Concentration
• Future Chemicals
• Temperature
• Internal Reactions
Tear and Puncture
One source of potential geomembrane failure is tear and punc-
ture. Polyethylene's tear and puncture properties are linear to
thickness. However, recent data show that the use of geotextiles
can greatly enhance the puncture resistance of a polyethylene
geomembrane. Typical results show that a 40 mil liner in conjunc-
tion with a 6 oz geotextile can give puncture values greater than
100 mil polyethylene alone. Not only does a cost savings occur,
but also one can expect other benefits, such as constant weld-
ing surface, subsoil stability, potential help in leak detention,
reduces abrasion and improved venting.
Seam Failure
Probably the most common cause of geomembrane failure is
seam failure. This failure usually is caused by poor workman-
ship in the field seaming.
SEAMING METHODS
Polyethylene seaming is unique because the bond can be
stronger than the parent material. Polyethylene seaming methods
do not include the addition of materials other than polyethy-
lene, and thus there are no seam failures caused by adhesives
not being resistant to the chemicals.
There are several polyethylene seaming methods, but all basic-
ally rely upon heating the two sheets to be bonded so that the re-
sultant seam is as one. All seaming methods require applied
pressure following the heating, and all rely upon time, tempera-
ture and pressure. Hot air simply melts the two surfaces to be
bonded. Fusion uses molten plastic to effect the bond. Extrusion
welding adds new material via the extrusion process either be-
tween two sheets or as a filet type weld. Finally, "hot shoe of
hot wedge" welding melts the surfaces to be bonded by use of a
hot metal shoe or wedge.
All of these systems will give an excellent weld that is stronger
than the parent sheet if done properly; conversely, all will give
poor welds if not done properly. In the field, extra care is needed
to ensure the best results. Sometimes unpredictable factors must
be accounted for (i.e., temperature changes, wind velocities and
contamination). In all methods, simple precautions such as pre-
cleaning the surface prior to seaming are common sense but quite
often are overlooked.
INSTALLATION
The installation of a polyethylene geomembrane not only is
the most critical step, but also is the most difficult step to man-
age and control. Because the liner is subject to uncontrollable
factors such as potential wind damage, traffic on the liner, etc.,
it is advisable to continually inspect the liner during installation
in addition to the final inspection upon completion. Because
seams are most prone to future problems, they should be given
the closest scrutiny.
INSTALLATION QUALITY
Upon arrival, the geomembrane should be inspected to ensure
no damage occurred in transit. Samples should be taken for ver-
ification of physical properties as well as thickness, etc. Before
installation commences, engineering and site specifications should
be checked for conformance. The placing of the liner should be
controlled to eliminate or minimize damage to the material. Once
seaming starts, it is important to do the testing and quality con-
trol along with the actual installation. This testing begins with
non-destructive tests. The four most common tests used with
polyethylene seams are:
• Air Jet Testing
• Impact Testing
• Ultrasonic Testing
• Vacuum Box Testing
The above non-destructive tests, in essence, only tell one
whether one has a leak or not; they do not test the integrity of
the seam. Even though these tests will show a seam that needs
immediate repair, they cannot be relied upon for complete qual-
ity analysis. Thus, it becomes essential to do destructive tests.
There are two destructive tests used with polyethylene:
• Tensile Testing
• Peel Testing
The peel test is considered the best method for assessing bond
strength. In this test, a force is applied against the bond in a
severe manner. A good bond will exhibit ductility and elonga-
tion, whereas a poor bond will crack or peel apart easily under
low force. If the bond is stronger than the liner, the liner will tear
away from the bond before the bond peels or breaks. This is re-
ferred to as film tear bond or "FTB."
270 BARRIER TECHNOLOGY
-------
It is advisable to keep samples of seams for future reference
and testing, if needed. During the seaming process, all conditions
for seaming should be checked before starting. Samples should be
produced under exact site conditions. All conditions for seaming
should be rechecked, and good seams should be verified if the
following excessive delays or major changes in the environment
occur:
• A temperature change of more than 10 °C
• A change in wind velocity of more than 15 miles/hr
• A change from dry to wet, etc.
• A change in the seaming surface
• A change in barometric pressure
MONITORING
In addition to the normal leak detection systems, it can be ad-
vantageous to make efforts to monitor the system to discover
potential problems before a leak occurs. A few recommendations
would be:
• Place coupons in the contained medium so that testing will
show if any side effects are taking place because of chemical
attack, exothermic reactions, etc.
• Place coupons above the containment line to measure any ad-
verse effects caused by ultraviolet light or weathering.
• Keep environmental records including wind velocities and
temperature extremes.
CONCLUSIONS
As long as geomembranes are used in the containment of haz-
ardous wastes, it is important to make the best evaluation pos-
sible in the selection process to reduce the chance for failure.
This paper deals mainly with polyethylene geomembranes, but
the points made would still have some validity with other syn-
thetic materials. Because of the dangers that can be associated
with a failure, it is important that everyone involved in the pro-
cess of liner production/installation cooperate in a joint effort
from inception to completion. It is hoped that this paper contrib-
utes to this effort, if only in a small way.
REFERENCES
1. Geotechnical Fabrics Report; Special Issue: Product Reference Guide
and Directory; 3, Nov./Dec. 1985.
2. Proc. International Conference on Geomembranes: I; Denver, CO,
1984.
3. Proc. International Conference on Geomembranes: II; Denver, CO,
1984.
4. Proc. International Conference on New Frontiers for Hazardous
Waste Management, EPA/600/9-85/025; Pittsburgh, PA, 1985.
5. U.S. EPA Lining of Waste Impoundment and Disposal Facilities;
SW-870, Washington, DC, 1983.
6. Managing Corrosion with Plastics, NACE V; Atlanta, GA, 1981.
7. Modern Plastics Encyclopedia, Volume 61, Number IDA, McGraw-
Hill, New York, NY, 1984-85.
8. Proc. Second Canadian Symposium on Geotextiles and Geomem-
branes, Edmonton, Alberta, 1985.
9. Standard Number 54, Flexible Membrane Liners; National Sanita-
tion Foundation, Ann Arbor, MI, 1983.
BARRIER TECHNOLOGY 271
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Nondestructive Testing Techniques to
Assess Geomembrane Seam Quality
Arthur E. Lord, Ph.D.
Department of Physics and Atmospheric Sciences
Robert M. Koerner, Ph.D., P.E.
Robert B. Crawford
Department of Civil Engineering
Drexel University
Philadelphia, Pennsylvania
ABSTRACT
A review of the various nondestructive testing (NOT) tech-
niques for geolmembrane seam integrity is given. A bonafide
NOT technique is desperately needed which will test 100% of all
field seams. At present, such a technique does not exist. In the
authors' opinion, ultrasonic techniques are the only ones which
will perform the task. Some experimental results are presented
for the pulse-echo and shadow ultrasonic methods on high density
polyethylene seams. The ultrasonic techniques should be devel-
oped to their full potential in order to assure that field seams in
geomembrane-lined landfills are as defect-free as possible.
INTRODUCTION
Liners and covers for hazardous waste landfills, surface im-
poundments and waste piles currently must use geomembranes
for the prevention of unwanted liquids leaving or entering the
contained waste. Almost every recent document regarding haz-
ardous waste landfills, surface impoundments and waste piles has
noted the need for 100% nondestructive testing of geomembrane
field seams.1 Current emphasis on construction quality assur-
ance (CQA) makes this need an absolute necessity. Not only are
seams along the sides and ends of full liner sheets important, but
also the liner connection details around connections and appur-
tenances are absolutely critical. These connections are very often
the cause of problems in lined waste facilities. Almost every study
recently conducted lists inspection of field seams as a major de-
ficiency. Additionally, these reports2' '• * target a nondestructive
testing method assessing 100% of the field seams as the highest
priority. In the absence of high quality seams and their inspec-
tion, the "de-minimum" limits for leachate entering into leak de-
tection systems of doubly lined facilities are ludicrous. One small
length of bad seam can easily generate the complete amount of
"de-minimus" leakage under almost any scenario. In the authors'
opinion, field seams of FML are the Achilles' heel of liner design,
construction and proper long-term functioning of waste manage-
ment facilities.
Results of chemical compatibility exposure (via U.S. EPA 9090
test procedures) generally leave the liner material of choice as
polyethylene. Furthermore, of the various available varieties of
polyethylene, high density polyethylene (HOPE) is usually the
liner material selected. While excellent for chemical compatibil-
ity, the constructability of HOPE is very difficult due to the
following features:
• HDPE is a relatively hard polymeric liner material (its Shore
Hardness is approximately 65 versus 20 to 30 for PVC)
• Due to this hardness and lack of flexibility, its conformability
to the subsoil after placement is very poor
• HDPE has a low coefficient of friction (12° to 20° on various
soils)
• HDPE yields at a very low elongation (10% to 20% typically)
• There is controversy about the proper field seaming methoc
(extrusion welding or thermal fusion) of HDEP with respect tc
the sheet thickness and its crystallinity
• The temperature window for seaming HDPE is very narrow
(typically 100 °F, dependent upon the degree of crystallinity)
• Overheating and/or burn through of thin sheets of HDPE
while making seams is not uncommon when using extrusion
welding
• Thermal fusion of thin sheets is then necessary for field seams
but generally is not used on thicker sheets
• Seaming around connections and appurtenances is very diffi-
cult irrespective of the seaming method.
• Superimposed upon the above listed difficulties of working
with HDPE, and more specifically its field seams, is the abso-
lute necessity of a rigorous CQA program
PROGRAM
Currently, the generally acknowledged need for quality seams
usually is satisfied with the compliment of periodic destructive
shear and peel tests (Fig. 1) to assess the specific seaming method
and procedure and with nondestructive methods like the air lance
or pick test (mechanical point stress) to assess seam continuity.
Sometimes vacuum box methods also are used but only on a spor-
adic basis. While a limited number of destructive tests probably
always will be necessary, the other tests mentioned fall far short
of a "true" nondestructive test method. Needed is a nondestruc-
tive test where operator experience, sensitivity and judgment arc
kept to a minimum. Certainly this is not the case for the air lance
or pick test which can be done in an almost cavalier manner. The
vacuum box method is indeed worthwhile, but it does not lend it-
self to 100% continuous testing or to use around connections
and appurtenances.
To give an overview of the entire seam monitoring spectrum,
Table 1, after Frobel,' is presented. Since concentration in this
article will be focused on HPDE, the NOT methods that one can
consider are:
Air lance (not recommended for geomembrane thickness
mils)
Vacuum chamber
Pressurized dual seam (for thermally fused seams only)
Electrical sparking
Mechanical point stress (pick test)
Ultrasonic pulse echo
Ultrasonic shadow
Ultrasonic impedance
These test methods will be discussed in the next section.
45
272 BARRIER TECHNOLOGY
-------
T
R»
(UnMOMd)
T T
• In Sh*or Sea* in P*«l
later!.I
Figure 1
Tensile Test Results of 60 mil HOPE Bulk Samples Compared to
Welded Seam Samples. Seams on the Same Material Tested in Shear
and Peel
DESTRUCTIVE AND NONDESTRUCTIVE
TEST METHODS
The need for destructive tests, whereby a test specimen is
actually cut from the seamed geomembrane and tested in tension
until failure occurs, probably always will be a necessity. Results
as shown in Fig. 1 for the unseamed material versus the seam
tested in shear and peel are typical.6 It is reassuring to ascertain
that the field-produced seam has the same values of mechanical
properties (strength, elongation, modulus, etc.) as does the parent
material. If these properties fall below accepted limits, then the
necessary adjustments must be made in the seaming procedures.
Such items are critically important to the designer, manufac-
turer, contractor and ultimately to the facility owner. They are
necessary items to qualitatively assess geomembrane seams. Their
problem, however, is that they must be taken sparingly since each
sample requires a patch (hence additional seaming) to be made at
that particular location. Typical guidelines for taking of field
seam test specimens are at the beginning of the morning and
afternoon work periods and at intervals of one per 500 to 1000 ft.
It is quite apparent that the areas between these test specimens
must also be adequate but cannot be tested in a destructive man-
ner. This is precisely what creates the need for nondestructive
tests. Such NDT tests should be performed on 100% of the
seamed geomembrane.
Shown in Table 1 are the available NDT seam testing methods
which will be reviewed briefly.
Air Lance
The air lance method uses a jet of air at approximately 50 lb/
in.2 pressure coming through an orifice of 3/16 in. diameter. It is
directed beneath the upper edge of the overlapped seam to detect
unbonded areas. When such an area is located, the air passes
through, causing an inflation and fluttering in the localized area.
The method works best on relatively thin flexible geomembranes,
Table 1
Available NDT Methods for Evaluating FML Seams, Modified from Frobel'
Geomembrane
system
Thermoplastics
(PVC, TN-PVC;
EIA)
Reinforced
Nonreinforced
Crystalline thermo-
plastics
(LDPE; HOPE)
Nonreinforced
Elastomers
(Butyl; EPDM;
CR; CO)
Reinforced
Nonreinforced
Thermoplastic
elastomers
(CPE; Hypalon;
T-EPDM)
Reinforced
Nonreinforced
Electronic
Air Vacuum Pressurized Electrical Mechanical Ultrasonic Ultrasonic
lance3 chamber0 dual seam sparkingc point stress pulse echo shadow
(5-15 MHz) (0.5-5 MHz)
XX X X
XX XXX
X X X X XX
XX X X
XX X X
XX X X
XX XXX
Ultrasonic
impedance
(160-185 kHz)
X
X
X
X
a Air lance should be restricted to thickness less than 45 mils; this method is not recommended for stiff sheeting.
*" Vacuum chamber should be restricted to 30 mils and greater due to deformation.
c Electronic methods do not work on EIA material.
BARRIER TECHNOLOGY 273
-------
but it works only if the defect is open at the front edge of the
seam, where the air jet is directed.
Vacuum Chambers
Vacuum chambers (boxes) have been used where a box 3 ft.
long with a transparent top is placed over the seam and a vacuum
of approximately 2.5 lb/in.2 is applied. When a leak is encoun-
tered, the soapy solution originally placed over the seam shows
bubbles. These bubbles are due to air entering from beneath the
liner and passing through the unbonded zone. The test is slow to
perform, and it is often difficult to make a vacuum-tight joint at
the bottom of the box where it passes over the seam edges (es-
pecially those encountered in thick HOPE geomembranes).
Pressurized Dual Seam
The pressurized dual seam method is one where two parallel
seams are made with Vi in. air space between them. This contin-
uous air channel is inflated to approximately 30 lb/in.2 for a
length of 100 to 200 ft. If no drop in pressure occurs, the seam is
acceptable; if a drop does occur, a number of alternatives can be
followed.
• The distance can be systematically halves until the leak is
located and repaired
• The difficult section can be tested by some other leak detection
method
• A cap strip can be sealed over the entire edge
Electric Sparking
Electric sparking is an old technique used to detect pinholes
in thermoplastic liners. The method uses a high-voltage (IS to
30kV) current and any leakage to ground (through an unbonded
area) will result in sparking. The method is not very sensitive to
overlapped seams of the type generally used in modern liners and
currently is used only in rare instances. A new variation of the
method is to embed a wire in the seam itself and test through the
bonded zone.
Mechanical Point Test
The mechanical point stress or "pick" test uses a dull tool (such
as a blunt screw-driver) under the top edge of an overlapped
seam. With care, an individual can detect an unbonded area
which is easier to lift than a properly bonded area. It is a rapid
test but obviously depends completely on the care and sensitivity
of the person doing it. Detectability is similar to that using the
air lance. Both tests are very operator dependent.
Ultrasonic Pulse Echo
Electronic techniques are the newest of the methods used to
evaluate seam integrity. The ultrasonic pulse echo technique is
basically a thickness measurement technique and is only for use
with nonreinforced FMLs like HOPE. Here a high-frequency
pulse (of about 0.1 u sec duration and center frequency a few
megahertz) is sent into the upper geomembrane and (in the case of
good seam) reflects off of the bottom of the lower one. If, how-
ever, an unbonded area is present, the reflection will occur at the
unbonded interface. Fig. 2 is a schematic diagram of the pulse
echo method with results for "good" and "bad" seams. Fig. 3
shows actual data from a 30-mil hot air welded HOPE seam,
where the pick penetration was 15/16 in. An echo from one
single geomembrane thickness is seen whenever the transducer is
less than 15/16 in. from the edge of the seam, and an echo from
two geomembrane thicknesses is seen whenever the transducer is
more than 15/16 in. from the edge.
Ultrasonic Shadow
Related to the pulse echo method is the ultrasonic shadow tech-
nique which uses similar equipment (although with physically sep-
arated transducers) but transmits a long pulse (about 50-100ji sec)
ri v—'\—{ Q.....V.
I- 14.lv- tv C»V»llf>t
Figure 2
Schematic Diagram of the Pulse Echo Ultrasonic Methods Used in
Testing Flexible Membrane Liner Seams. Pictorial Representations
of the Response of a "Good" and "Bad" Seams are Given.
I ' I ' I
KEX
T r—
' li.m^.0
Figure 3
Actual Data Using the Pulse Echo Ultrasonic Method. The Results are
the HOPE of 60-mil Thickness. The Pick Penetration in this Case was
15 16-inch. Note the First Echo Wherever the Pick Penetrates.
of ultrasonic energy rather than a short pulse. In this method, a
good seam will convey most of the energy, while a poor or bad
seam will convey little or none of it. By comparing received sig-
nals on a CRT screen, a qualitative seam assessment can be
made. Fig. 4 shows a schematic diagram of the shadow method
and the results for "good" and "bad" seams. Fig. 5 shows
actual data for extrusion welded HOPE seams of 30 to 60 mil
thickness. The varying amplitude of response indicates varying
seam quality.
Ultrasonic Impedance Plane
The ultrasonic impedance plane method functions on the prin-
ciple of acoustic impedance. A continuous wave of 160 to 185
kHz is sent through the seamed liner, and a characteristic dot pat-
tern (representing the tip of the acoustic impedance vector) is
displayed on a CRT screen. Calibration of the dot pattern is re-
274 BARRIER TECHNOLOGY
-------
Signal Ottnaratar and
f CRT DIspIay flon I tor-
Larg*
—Tran*»l»*lan Plastic
^ Slgnltura
g«
Trannlnlon
Sign I tut-.
Figure 4
Schematic Diagram of the Shadow Ultrasonic Method Used in
Testing Flexible Membrane Liner Seams. Pictorial Representations
of the Response of a "Good" Seam and a "Bad" Seam are Given.
Indlcalion of
Shadow
Bianilur*
nominal
ThlcknMi of HOPE
Undv Inspection
30 mil
60 mil
Ullrtuonlc Shadow Bianilurt
Indicating Qood Overall
S«am InlMrtlu
Ultraaonlc Shadow eianllurt
Indicating Poor Seam
Intagrllu In Bom* or All
P«r/armanc« Standard*
Figure 5
Actual Data Using the Shadow Ultrasonic Method. The Results are for
HOPE of 30 and 60-mil Thickness.
quired to signify a good seam; if the dot falls away from the cal-
ibrated position, a bad seam is indicated. Fig. 6 is a schematic
diagram of the ultrasonic impedance plane setup, with the dot
position indicated for good and bad bonds. The method has
potential for all types of geomembranes but still needs additional
development work. The authors of this paper have not worked
directly with this method.
The pulse echo and impedance plane methods can be used only
on surfaces that are reasonably flat, whereas the shadow method
works on all types of seams. Many (not all) extrudate welds have
a "bead" and are not at all flat, while the hot air and hot wedge
seams are quite flat.
In closing this section of the paper, it should be mentioned that
none of the tests described has been standardized by ASTM,
NSF or other like body. Hence, testing of field seams is not con-
sistent from one job to the next.
coluar
\
1
»
T
•
/
\"^^,~
LJ
Uat«r lot
- Coupl Ing
BI gno I Oanora tor* and
CRT DKploy
*p I ay Ron 1 tor
Trant I tt.d
Signal
lBtIc Dot or.
Calibrated C*nt«r positio
Indicating Good Bonding
z
JJ_L
Charactttrlaftlc Dot off
Calibrated C«nt«r Position
Indleatlng Unbondlng
Figure 6
Schematic Diagram of Ultrasonic Impedance Plane Method Used
in Testing Flexible Membrane Liner Seams. Pictorial Representations
of the Response of a "Good" and "Bad" Seam are Given.
CONCLUSIONS
Upon reviewing the numerous comments suggesting the use of
NOT field testing of geomembrane seams, the lack of published
information regarding ultrasonics and other NOT methods is sur-
prising. For example, a recent conference in West Germany on
FML lined hazardous waste landfills' cites the potential use of
ultrasonics ten times but never gives data (except one small de-
scriptive figure like Fig. 2) and gives no references on the sub-
ject. Also, no data or references are given for any of the other
NOT techniques.
Peggs8- 9 has presented work on the shadow method and
Spanner10 has reported on work with the impedance method. Two
other references11'12 also are available using the shadow method,
but do not apply directly to geomembranes. Certain companies
claim to use pulse echo ultrasonics "routinely" on geomembrane
field seams, but no data are available showing the statistical cor-
relation of their results to other direct measures of seam integrity.
At present there is no NDT method which has the necessary
background research and data to qualify it as a bonafide, reliable
geomembrane seam testing device. In the authors' opinion, the
ultrasonic techniques offer the best potential for a true NDT
method. The ultrasonic methods alone, of all the NDT methods
described, can be used at a rate fast enough (10 to 20 ft/min) to
inspect 100% of the seams at a typical field site in a reasonable
length of time. Operation subjectiveness and error are reduced
considerably using ultrasonic methods compared to the other
NDT methods. Ultrasonics can be used on all types of seams, and
the shadow method can be used around connections and appur-
tenances. "Hard copy" can be produced and real-time audio
alarms can be actuated over a defective area.
Desperately needed is a detailed experimental program where
the results of ultrasonic methods are correlated with other im-
portant seam parameters such as:
• Seam strength
• Seam elongation at failure
• Seam permeability
• Seam mode of failure
This is a very ambitious task, but of extreme importance when
one considers the effects of leakage of a lined landfill, waste pile
or surface impoundment.
BARRIER TECHNOLOGY 275
-------
REFERENCES
1. Giroud, J.P., "Synthetic Pond Liner Assessment," for Battelle
Pacific Northwest Laboratories, Rich land, WA, June 30, 1983.
2. Shultz, D.W., "Field Studies of Liner Installation Methods of Land-
fills and Surface Impoundments," U.S. EPA-600/S2-84-168, 1985.
3. Bass, J.M., Lyman, W.J. and Tratnyek, J.P., "Assessment of
Synthetic Membrane Successes and Failures at Waste Storage and
Disposal Sites," U.S. EPA 600/S2-85/100, 1985.
4. Matrecon, Inc., "Lining of Waste Impoundment and Disposal
Facilities," Draft Final Report to U.S. EPA, 1984.
5. Frobel, R.K., "Method of Constructing and Evaluating Ceomem-
brane Seams," Proc. Intl. Conf. on Geomembranes, Denver, CO,
June 1984, IFAI, pp. 359-364.
6. Koerner, R.M., Designing with Geosynthetics, Prentice-Hall, Engle-
wood Cliffs, NJ, 1986.
7. Koerner, R.M., Wa»te and Refuse, Erick Schmidt Publishers, 22,
1985, 1-111, (In German).
8. Peggs, I.D., "Why Quality Control; A Graphic Case History,"
Proc. Geoteck Fabrics Conference '85, Cincinnati, OH, June 1985
35-42.
9. Peggs, I.D., Briggs, R. and Little, D., "Developments in Ultra-
sonic* for Geomembrane Seam Inspection," Proc. Canadian Ceo-
textile Conf., Edmonton, Alberta, 1985.
10. Spanner, G.E., "Nondestructive Technique for Assessing Field Seam
Quality of Prefabricated Geomembranes," Proc. Intl. Conf. on
Geomembranes, Denver, CO, June 1984, 369-373.
11. Dickson, J.K., "Investigation into the Inspection of Bonded Joints
on Inflatable Boats," Balteau Sonatest Ltd., North Bucks, England,
Aug. 1980.
12.Badgerow, D.L., "New Development in Ultrasonic Joint Inspection
for Polyethylene Systems." Am. Gas. Assn. Distribution Conf.,
Houston. TX, May 1983.
276 BARRIER TECHNOLOGY
-------
Attenuating Contaminant Migration with
Neutralizing and Sorptive Admix Barriers
B.E. Opitz
D.R. Sherwood
W.J. Martin
Pacific Northwest Laboratory
Richland, Washington
ABSTRACT
The milling of uranium ore produces large quantities of acid
waste (mill tailings) that are deposited in earthen pits or reposi-
tories. These wastes, which remain potentially hazardous for long
time periods, may reach the biosphere at levels greater than those
allowed by the U.S. EPA. As a result, technologies must be de-
veloped to ensure that such wastes will not reach the biosphere at
hazardous levels.
Pacific Northwest Laboratories (PNL) investigated the use of
various neutralizing reagents and techniques and the use of
engineered barriers to attenuate the movement of contaminants
associated with acidic mine waste. The objective of this study was
to identify the contaminants that are, and are not, effectively at-
tenuated by common neutralization methods. For those consti-
tuents not effectively attenuated by neutralization, our objectives
also included developing and testing alternative control measures
such as specific ion removal techniques. Results of these investiga-
tions led to the development of: (1) a low permeable, neutralizing
barrier composed of lime and coarse-grained sediment, and (2)
tailings additive comprised of a mixture of lime and barium
chloride, which, when added to acidic tailings, can reduce the
amount of teachable radium escaping a designated tailings im-
poundment.
The barrier was developed as a low-cost alternative to clay liner
schemes for use in areas where clays were not locally available and
must be shipped to the disposal site. In laboratory verification
tests, the neutralizing and sorptive barrier reduced the effluent
solution concentration of several constituents (e.g., Al, As, Cr,
Fe, V, total Ra,21°Pb, 230jh and total dissolved solids) by greater
than 90% in comparison to concentrations found in untreated
leachate samples. Furthermore, the neutralizing and sorptive bar-
rier inhibited drainage resulting from permeabilities on the order
of 10-8 cm/sec.
INTRODUCTION
In 1981 the Nuclear Regulatory Commission expanded the
scope of the uranium research program at PNL to address the use
of tailings neutralization for immobilizing toxic materials in acidic
uranium mill waste. The objective of this project was to assess
viable alternatives for reducing contaminant mobility under a full
range of site and environmental conditions. Laboratory ex-
periments were performed to test various neutralizing agents, to
evaluate their performance and to optimize treatment conditions
for contaminant immobilization.2*3'4 The results of these batch
treatment experiments indicated that calcium alkalies [CaCO3 and
CafOIDj provide the highest quality neutralized effluent at the
lowest cost.
The neutralization process is very effective in attenuating a high
percentage of the dissolved constituents contained originally in
acidic UMT solutions. However, certain constituents commonly
associated with tailings solution are not strictly dependent on
solution pH for their solubility in uranium tailings liquors. There-
fore, the activities or concentrations of these constituents show
only slight and sometimes no attenuation after solution
neutralization. One of these constituents not ideally controlled by
neutralization is radium.
Control or attenuation of radium is of special concern primar-
ily because of its radiological health implications. Current U.S.
EPA guidelines call for total radium activities not to exceed
5 pCi/L. Due to the high activity of soluble radium in the acidic
UMT environment (several hundred to several thousand pCi/L),
specific ion removal procedures were investigated for use in atten-
uating radium in order to prevent future groundwater contamina-
tion.
In this study, we performed further laboratory tests using lime
neutralization. In these tests, lime was mixed as an additive into
overburden material from the Exxon Highland mill site in Con-
verse County, Wyoming. The study's objective was to test a
method of amending coarse-grained materials to improve their
ability to retard contaminant migration.
In addition, we performed laboratory tests using lime
neutralization plus barium addition (in the form of barium
chloride) to the tailings directly. These tests evaluated a method
of amending solid acidic tailings in order to attenuate the migra-
tion of contaminants from the waste source and reduce the poten-
tial for future groundwater contamination.
MATERIALS AND METHODS
For the purposes of assessing the performance of the barriers,
columns of both overburden and tailings were compacted with
and without chemical amendments. The calcium hydroxide
amendment was mixed into the tailings as an oven-dried solid.
Table 1
Description of Columns Containing Overburden and Tailings
Column ID
1
2
3
4
5
6
Description
1000 g tailings, 7.3 g Ca(OH)2,
151 ml BaC12 solution.
1000 g tailings, 151 ml DD H20.
1000 g overburden, unamended,
high density
1000 g overburden, 50 g Ca(OH),,
high density £
1000 g overburden, unamended
low density
1000 g overburden, 50 g Ca(OH)?,
low density
BARRIER TECHNOLOGY 277
-------
Barium chloride was added to the tailings in liquid form after
dissolving 3.286 g/1 of BaCl2-2H2O in distilled, deionized water
(DD H2O). Distilled deionized water only was added to the un-
treated tailings not containing barium chloride. The descriptions
of the amended and the untreated tailings columns are shown in
Table 1.
Once compacted, the columns containing the amended tailings
mixtures and the untreated tailings were leached with local
ground water. The columns containing the amended and un-
treated overburden were contacted with Exxon tailings solution as
collected from the tailings solution pond. The chemical composi-
tions of the local groundwater and the tailings solution are shown
in Table 2.
Table 2
Groundwater and Tailings Solution Chemical Composition
Parameter
Al
As
Ba
Ca
Co
Cr
Cu
Fe
K
Mg
Hn
Na
Se
S1
In
Cl
so4
Total dissolved
solids (g/l )
pH
Local
Groundwater (itig/1 )
0.1
<0.02
0.03
25.1
ND
ND
0.04
0.9
4.4
<0.3
2.9
ND
3.6
0.2
1.5
19.8
0.6
8.2
T«1Hngs
Solution (mg/1 )
440
0.21
<0.1
560
1.31
1.25
0.97
1000
44
540
50
340
1.35
310
4.5
300
9300
12.9
1.9
(a) ND - Not Determined
RESULTS
Radium Attenuation Experiments
The results of the radium attenuation experiments, which com-
pare the untreated tailings with the amended tailings, are shown
in Fig. 1. The first sample collected from the untreated acidic tail-
ings at an adjusted pore volume of 0.51 contained 3345 pCi/L of
soluble radium. As local groundwater contact continued, the ac-
tivity of the radium leached from the acidic tailings decreased to
1218 pCi/L after 1.6 pore volumes of leaching. The final sample
collected in these experiments contained 570 pCi/L at an adjusted
pore volume of 2.8, still over two orders of magnitude higher than
the U.S. EPA's drinking water limit of 5 pCi/L total radium. The
amended tailings column [neutralized with Ca(OH): plus BaCl2
added] displayed a high degree of radium attenuation throughout
the duration of the experiment. The initial radium activity in the
sample collected at an adjusted pore volume of 0.6 was 1.7
pCi/L. This decrease represents a reduction in total radium activ-
ity of greater than three orders of magnitude compared to the first
sample collected from the untreated acidic tailings. With con-
tinued leachant contact, the radium activity showed an additional
reduction to 1.1 pCi/L at 1.72 adjusted pore volumes. The last
sample collected from the amended tailings column displayed a
slight increase in radium activity. At an adjusted pore volume of
2.8, 6.1 pCi/L of soluble radium were detected in the column ef-
fluent. Although the final sample collected from the amended
tailings column was 1.1 pCi/L higher than the U.S. EPA's drink-
ing water limit, a value of 6.1 pCi/L represents a decrease of near-
ly two orders of magnitude over the untreated tailings column at
similar leaching volumes.
xooo
1,000
a 100
•*
o
<
I
•6
•
cr
10
5
1.0
0.1
0.01
— Neut. * BaClz
— Untreated
1
1
1
1
0.4 0.8 1.2 1.6 2.0 2.4
Adjusted Pore Volume
2.8
Fig. I
Resulis of Treated and Untreated Tailings Experiments
The mechanism that accounts for the removal of soluble
radium from the tailings effluent solution is assumed to be co-
precipitation. The reactants in the amended tailings material are
BaCl2 and radium from the acidic tailings. The reaction is shown
in equation (1) and is probably the most common method for
radium removal from solution.5
BaCl2 + Ra2 + + SOj-= 2CT+ (Ra,Ba)SO4 (1)
As barium sulfate is precipitated, radium is effectively removed
from solution by adsorption onto the precipitate surface or is in-
corporated into the lattice structure of the solid precipitate.
Radium removal is very much dependent on the solution
parameters associated with the precipitation reactions. For ex-
ample, there must be an excess of sulfate in solution and the
kinetics of the co-precipitation reaction are sometimes slow so
adequate column residence time or reaction time (ranging from
hours to days, dependent on conditions) is necessary.5-6 Since
most U.S. mills use a sulfuric acid leach cycle, excess sulfate
typically is present. Furthermore, by neutralizing the acidic tail-
ings, the reactants (BaCl2 and radium) are retained in the column
long enough for the reaction to occur.
Tailings neutralization causes the pH-dependent ions to
precipitate in the pore spaces within the column. The solids
formed plug the pathways through which solution normally trav-
els, reduce the flow rate of leachant through the neutral tailings
and, therefore, increase the residence time for reactions.
Permeability and Leaching Experiments
The calculated permeability values for both the untreated
Exxon overburden and the overburden with 5% lime versus the
number of pore volumes of effluent tailings solution are plotted
in Fig. 2. The graph indicates permeabilities were nearly identical
at the start of the experiment. The untreated overburden dis-
played permeabilities in the range of 4 x 10-* cm/sec to 1 x
10-6 cm/sec during contact with approximately 24 pore volumes
of acidic tailings solution. The Exxon overburden with 5% lime
displayed an initial permeability of 3.5 x 10-6 cm/sec followed
by a rapid decrease in column flow rates as contact with add tail-
ings solution continued.
278 BARRIER TECHNOLOGY
-------
10"
3
LU
10'
TREATED
— UNTREATED
i I i I i I
I
8 12 16
PORE VOLUME
20
24
Figure 2
Permeability vs. Pore Volume Comparison Between
Untreated and Treated Overburden (with lime)
After interaction with approximately four pore volumes of tail-
ings solution, the permeability of the lime-treated overburden
decreased over one order of magnitude to 5 x 10 ~7 cm/sec.
After 20 pore volumes of acidic solution contact, the permeability
decreased to 4 x 10-8 cm/sec and remained at that flow rate un-
til a total of 24 pore volumes of uranium tailngs solution had con-
tacted the lime-treated Exxon sediment. This final permeability
represents a decrease of two orders of magnitude over the course
of 24 pore volumes of acid solution contact.
Solution Chemistry
The chemical compositions of the effluents collected from both
the untreated acidic tailings and the amended tailings columns are
shown in Table 3. The data indicate that in addition to a substan-
tial reduction in total radium activity, similar reductions were
Table 3
Solution Compositions of Untreated and Treated
Tailings Effluent
Untreated
pH
Adjusted pore
volume
Total dissolved
solids (g/l)
Total radium
(PC1/1)
Macro Ions
(mg/l 1
Al
As
Ba
Ca
Co
Cr
Cu
F*
*)
Hn
Na
Se
SI
In
Cl
S04
1
2.40
0.52
7.22
3345
2100
2.82
<0.06
610
5.33
2.70
2.69
1400
1740
197
1000
0.24
60
32
510
25600
z
2.65
1.64
2.46
1218
570
0.76
<0.02
560
1.22
0.89
0.76
390
472
50
360
<0.03
34
7.8
170
8100
3
2.77
2.77
1.70
570
300
0.43
<0.02
610
0.83
0.55
0.34
240
254
26
230
<0.02
30
-------
both the untreated and treated overburden indicate a substantial
reduction in solution constituent concentrations. The total
dissolved solids (TDS) content in the effluent from the untreated
sediment column after 1.6 pore volumes of solution contact was
reduced by 63%, while the lime-amended sediment showed reduc-
tions greater than 76"% after 1.8 pore volumes of solution/sedi-
ment interaction.
The reduction in solution consistent concentration can be at-
tributed to two mechanisms: sediment adsorption interactions
and, more importantly, precipitation reactions caused by influent
solution neutralization. High concentrations of macro ions (i.e.,
Al, Fe, Mg, Mn, Si and SOJ and trace metals (i.e., As, Co, Cr,
Cu and Zn) in the very acidic (pH 1.9) tailings solution exceed
their solubility limit and form precipitates as the solution ap-
proaches a neutral pH. The effects of solution neutralization con-
tinue until the sediment's buffering capacity is expended (primar-
ily the dissolution of CaCOj contained in the sediment).
14
13
12
11
10
9
* 8
7
6
5
4
3
2
TREATED
—. UNTREATED _
I I I I
T
T
T
4 6 8 10
PORE VOLUME
12
14
16
Figure 3
Acid Breakthrough Curves for Untreated and Treated Overburden
The acid breakthrough curves shown in Fig. 3 illustrate the
ability of the untreated overburden to buffer several pore volumes
of acidic uranium tailings solution. In the case of the overburden
with no lime, approximately four pore volumes of tailings solu-
tion contacted the sediment before the buffering capacity was ex-
pended. As solution contact continued, the effluent solution pH
decreased rapidly (higher acidity), and after a total of five pore
volumes of acid solution contact, the effluent solution was ap-
proximately pH 3.5.
Data for the effluent from column 5 (untreated overburden) in
Table 4 shows the TDS content approaching that of the influent
solution after 4.7 pore volumes of contact. After 7.3 pore
volumes of tailings solution interaction, the effluent solution was
pH 3.0 and had begun to redissolve part of the initially formed
precipitates, as indicated by the TDS content and individual con-
stituent concentrations being higher than originally present in the
influent solution.
The treated Exxon overburden representing the neutralizing
barrier exhibited a much greater buffering capacity because of the
addition of 5% lime. The acid breakthrough curve, as shown in
Fig. 3, illustrates how an increase in buffering capacity signifi-
cantly increased the ability of an existing sediment to retard con-
taminant migration via neutralization reactions. After 15 pore
volumes of tailings solution contact, the effluent solution from
the lime-amended sediment column remained highly alkaline (pH
12.8). In addition, the solution constituent concentrations and/or
TDS content continued to be significantly reduced (see Table 5).
The data for the four effluents analyzed (Table 5) demonstrate
the barrier's capability to reduce the quantities of dissolved solids
in effluents from uranium tailings ponds. Effluent #4 (Table 5)
has 4.67 g/1 TDS remaining in the effluent solution after 17.9
pore volumes of contact (reduced 63% from influent levels). In
other words, approximately 8.2 g/1 (influent dissolved solids
minus effluent dissolved solids) of precipitates continue to be
deposited within the column sediment. After 17.9 pore volumes
of solution contact (268 mL/pore volume as per Table 1), approx-
imately 41 g of precipitated solids were deposited in the lime-
amended sediment. In effect, the deposition of the solids gradual-
ly increased the column's overall bulk density (1.39 g/cm3 to 1.46
g/cm*) and therefore decreased the porosity (0.49 to 0.46) of the
compacted sediment. The gradual accumulation of precipitates,
deposited within the pore space of the sediment, plugs the
pathways through which solution normally migrates and results in
a decrease in sediment permeability (such as observed in Fig. 2) as
tailings solution/sediment interaction continues.
CONCLUSIONS
The results of these tests indicate that barium chloride addition
to tailings can effectively limit the amount of soluble radium
leached from acidic uranium mill tailings. Initial radium activities
in the untreated acidic tailings (0.52 pore volumes) were greater
than 3300 pCi/1. After 2.8 pore volumes of leaching, the radium
activities were 570 pCi/l; still greater than two orders of
magnitude higher than the U.S. EPA's water standard of 5 pCi/1.
At similar pore volumes, the radium activity of the barium-
treated tailings was 1.7 pCi/1 (0.60 pore volumes); equivalent toa
reduction by a factor of greater than 1900. At 2.8 pore volumes,
the radium activity was 6.1 pCi/1; a reduction of nearly two
orders of magnitude.
The results of the overburden amendment studies indicate that
a neutralizing barrier comprised of a sandy loam material and
lime can be an effective barrier to acidic seepage. Dissolution of
lime within the barrier not only buffers the acidity, but also pro-
vides a source of calcium for the precipitation of sulfate as gyp-
sum (CaSO4 - 2H2O). The removal of soluble sulfate from the ef-
fluent constitutes the major portion of the TDS reduction.
Precipitation of nearly two-thirds of the influent TDS content
was maintained in the neutralizing barrier columns through the
17th pore volume, whereas the untreated overburden columns
eluted a higher TDS content than the influent after only about 7
pore volumes.
Tailings treatment techniques such as barium chloride/hy-
drated lime treatment and neutralizing barriers effectively reduce
the TDS content, the trade contaminant content and the velocity
at which effluent can seep. Using such a barrier appears to be a
viable alternative for limiting the migration of acidic seepage
through coarse-grained sediments and geologic formations.
ACKNOWLEDGMENTS
This work was sponsored and supported by the Office of
Nuclear Regulatory Research of the Nuclear Regulatory Commis-
sion under contract DE-AC06-76RLO 1830, NRC FIN B2370. The
authors acknowledge Mr. Frank Swanberg, who was the technical
monitor of this project, Mr. Robert Poyser at Pathfinder Gas
Hills Mill and Mr. Tom Yarnick and Mr. David Clark at Exxon
Highland Mill.
REFERENCES
1. Sherwood, D.R. and Seme, R.J.. "Tailings Treatment Techniques
for Uranium Mill Waste: A Review of Existing Information,
NUREG/CR-2938 (PNL-4453), U.S. Nuclear Regulatory Commis-
sion, Washington, D.C. 1983.
280 BARRIER TECHNOLOGY
-------
2. Sherwood, D.R. and Seme, R.J., "Evaluation of Selected Neutral-
izing Agents for the Treatment of Uranium Tailings Leachates: Labor-
atory Progress Report," NUREG/CR-3030 (PNL-4524), U.S. Nu-
clear Regulatory Commission, Washington, D.C., 1983.
3. Opitz, B.E., Dodson, M.E. and Seme, R.J., "Laboratory Evaluation
of Limestone and Lime Neutralization of Acidic Uranium Mill Tail-
ings Solution: Laboratory Progress Report," NUREG/CR-3449
(PNL-4809), U.S. Nuclear Regulatory Commission, Washington,
D.C., 1983.
4. Opitz, B.E., Dodson, M.E. and Serne, R.J., "Uranium Mill Tailings
Neutralization: Contaminant Complexation and Tailings Leaching
Studies," NUREG/CR-3906 (PNL-5179), U.S. Nuclear Regulatory
Commission, Washington, D.C., 1985.
5. Moffett, D., "The Disposal of Solid Wastes and Liquid Effluents
from the Milling of Uranium Ores," CANMET Report 76-19. Canada
Centre for Mineral and Energy Technology, Ottawa, Canada, 1976.
6. Levins, D.M., "Mobilization of Radionuclides and Heavy Metals in
Uranium Mill and Tailings Dam Circuits." Presented at The Office of
the Supervising Scientist Workshop, Jabiru, Australia, May, 1983.
BARRIER TECHNOLOGY 281
-------
Geomembrane Barrier Technology
For Superfund Cleanup
Mark W. Cadwallader
Gundle Lining Systems Inc.
Houston, Texas
ABSTRACT
Superfund cleanup work requires careful consideration of the
latest developments in barrier technology. High quality geomem-
branes have proven very useful in dealing with the monumental
problems posed by toxic and hazardous wastes. This paper deals
with issues of material selection in barrier technology and reports
on the emerging options for barrier wall construction with geo-
membranes.
INTRODUCTION
The Superfund program has taken a first step toward solving
one of the most perplexing environmental challenges of all time,
i.e., improper past disposal of hazardous waste. The true cost of
past waste disposal practices is confronting this country as a vivid
reality, and billions of dollars are being set aside for cleaning up
the environment. Since we did not pay to properly dispose of the
waste before, we are paying now.
But what are proper waste disposal techniques? Many people
talk about waste recycling or incineration as though they are the
panacea to the hazardous waste problem. Yet neither solution
is a complete answer; quite hazardous non-reusable waste and
ash still remains. The above-cited methods are suitable only for
certain wastes. Deep-well injection, another viable disposal tech-
nique, also has limited application, in this case to certain liquid
wastes. The simple truth is that disposal and containment of
waste products on the earth's surface must continue for lack of a
better alternative.
Since surface containment of waste is necessary, the most real-
SOLID WASTt
FILTER
HEHIRANE
FML
FML
• PRIMARY LEACtATE COLLECTI $*..•'.;.'.•. :'.•:';'.•':'•.•".•:.'
SECOKDARY LEACHATE COLLECTIOX ;•..••; :;V-
\\TT\\\\\\\\\\\\\
COMPACTED LOW PERMEABILITY SOIL
'•*.°o*e°o* XATIVE SOIL FOUNDATION
Figure 1
Type 1 Double Liner System for Landfill1
istic approach is to provide the best possible barrier for waste con-
tainment. If money is spent on appropriate barriers to waste mi-
gration, savings result because future cleanup operations become
unnecessary. Also, if costs are increased for traditional surface
containment because of better barrier construction, desirable al-
ternatives such as recycling become more cost-competitive. In-
centive therefore develops to conserve and recycle waste.
The U.S. EPA has recognized the importance of improving the
barriers to waste migration in hazardous waste containment In
November of 1984, RCRA was modified to contain more rigor-
ous minimum technology requirements for land disposal facil-
ities. Certain landfills and surface impoundments now are re-
quired to have "two or more liners and a leachate collection sys-
tem above (in the case of a landfill) and between such liners"
(Fig. 1).
DEVELOPMENT OF BARRIERS FOR
WASTE CONTAINMENT
Over the years, a number of different types of materials, both
natural and synthetic, have been available for use as barriers in
waste landfills and impoundments:
Clay
Bentonite Clay
Bentonite Slurry Walls
Cement Stabilized Sand
Bitumen
Asphalt
Grout Curtains
Steel Sheet Pilings
Flexible Membrane Liners (FMLs)
- Butyl Rubber
Chlorinated Polyethylene (CPE)
Chlorolsulfonated Polyethylene (CSPE-Hypalon)
Epichlorohydrin Rubber (ECO)
- Ethylene Propylene Rubber (EPDM)
- Ethylene Propylene Terpolymer (EPT)
Low Density Polyethylene (LDPE)
High Density Polyethylene (HOPE)
Neoprene (Chloroprene Rubber)
Polyvinyl Chloride (PVC)
- Thermoplastic Elastomers
Clays, including bentonite (which swells to increased imper-
meability when in contact with water), had proven the most prac-
tical and popular. Permeability studies, however, have shown
that certain alkaline solutions and hydrocarbons can seriously
affect the impermeability of clays.2-3
Conventional clay permeability tests using water with 0.01 N
CaS04 qualify most clay soils for lining hazardous waste disposal
282 BARRIER TECHNOLOGY
-------
facilities on the basis of their having permeabilities lower than 1 x
1Q-7 cm/sec. However, when the same clay soils are subjected to
permeability tests with solutions of organic fluids, they undergo
large permeability increases exceeding permeabilities of 1 x 10 ~7
cm/sec. Reintroduction of plain water does not return the soil to
its original permeability, thus implying some structural alterations
caused by the interaction of organic chemicals with compacted
clay soil. This change in permeability is beh'eved to be due to the
organic fluids tending to pull the soil particles in the clay into
aggregations of many particles resulting in the formation of large
interconnected pores.
Acidic or basic leachate also has been found to disrupt clay
barriers with permeability increases.4 The mechanism in this case
is dissolution of the soil binding agents in the clay followed by
movement of the clay particles out of the barrier.
In addition, the actual field permeability of compacted clay lin-
ers apparently greatly exceeds laboratory measured clay perme-
abilities. Laboratory permeability tests do not take into account
the presence of cracks, fissures and inter-clod voids which appear
by virtue of the larger scale in the field.5 Cement stabilized sand
can also crack, especially in the presence of acidic conditions.
Steel sheet piling will rust, especially in the presence of acids.
Synthetic flexible membrane liners (FMLs) are therefore high-
ly attractive because of their negligible permeability and good
chemical resistance. As can be seen from the previous list of
potential materials used as liners, many different polymers have
been used in geomembranes. Only a few, however, have achieved
widespread use for applications in which fluid containment is
absolutely critical—such as for containment of hazardous chem-
ical wastes. Only a few have the long-term durability to with-
stand harsh environment for many years. In the short history of
FMLs, the industry has been quick to adopt the most appro-
priate polymeric material for waste containment available. This
means that the most commonly used polymeric material for FML
manufacture has changed as polymer technology has progressed.
In the same way that the airplane industry's choice material of
construction has gone from wood to aluminum, the waste con-
tainment industry's choice material for FMLs has gone from
butyl rubber to high density polyethylene (HOPE). This histori-
cal progress is displayed in Fig. 2.
Figure 2
Life Cycle of the Most Commonly Used Chemically Resistant
Synthetic Liners
With the advent of copolymer pipe grade HDPE technology,
geomembranes can now boast of strength, toughness, durability,
chemical resistance and environmental stress crack resistance. The
qualities of HDPE as a barrier material are also increasing its
applications in the container market. Much growth is expected
for HDPE containers of agricultural chemicals, insecticides, herb-
icides, paint thinners, household chemicals and other chemical
products.' HDPE is expected to replace more and more tra-
ditional metal and glass containers in the market place.
Advances in HDPE resin technology are responsible for its in-
creased use as a barrier membrane for chemicals; hence, its in-
creased (and almost exclusive) use in geomembranes for haz-
ardous waste landfills and surface impoundments. But to pro-
vide maximum barrier protection, the proper grade of HDPE
should be utilized. For instance, linear low density polyethylenes
(LLDPE) also utilize the new copolymer technology, as do the
pipe grade HDPE resins. Yet, because of their lower density
and molecular weight, they do not provide the chemical resis-
tance, strength and durability that the pipe grade HDPE resins
do. To test their respective barrier performances, the chemical
immersion test described in the next section was performed on co-
polymer HDPE and LLDPE.
CHEMICAL RESISTANCE STUDY
Chemical immersion testing of geomembranes presently is re-
quired by the U.S. EPA before approval of new hazardous waste
facilities is granted. The protocol for testing is outlined in U.S.
EPA Method 9090. Because of such routine testing, in addition
to data generated by the resin manufacturers, there exists a con-
siderable volume of information regarding the chemical resis-
tance of HDPE.
Apart from a few strong oxidizing acids, there are few chem-
icals which damage pipe-grade quality copolymer HDPE ma-
terials. Organic solvents may be absorbed into the liners caus-
ing some softening with a corresponding decrease in physical
property performance. However, they do not actually degrade
the HDPE.
Degradation of a geomembrane liner is interpreted as an irre-
versible process in which useful polymer properties degenerate
when exposed to the environment. The degradation takes place
because of the rupture of primary and secondary chemical bonds
in the polymer matrix. Chemical species as well as energy sources
cause the destruction of polymer bonding.7
As a part of this study, a chemical immersion test was con-
ducted. Sixty mil thick (1.5 mm) pipe-grade quality copolymer
HDPE geomembrane liner was immersed in 100% dichloro-
ethylene. The chlorinated hydrocarbon was chosen because of re-
portedly degradative action on HDPE. U.S. EPA Method 9090
provided the test procedure pattern for the chemical resistance
testing. The test differed from the U.S. EPA method in that
sample specimens for testing were cut prior to immersion. This
allowed more liner contact with hazardous solvents and a reduced
volume of solvent necessary for testing. Testing was continued
for 150 days instead of the 120 days required by the U.S. EPA.
The following tests were performed:
Test
Method
Tensile Properties
Initial Tear Resistance
Puncture Resistance
Weight Change
Thickness Change
ASTM D638, Type IV Specimen 2 ipm
ASTMD1004, Die C
ASTM 101B, Method 2065
1 x 3 in. Specimen
1 x 3 in. Specimen
Two temperature conditions were maintained for each chem-
ical solvent in the study; 23 °C and 50 °C (as per Method 9090).
Tables 1 and 2 list the results of the study. Sample specimens
were cut both parallel to machine direction as well as perpendicu-
lar to machine direction in order to check any possible polymer
orientation effects. Three specimens were tested for each line
entry in Tables 1 and 2. Specimens were checked at 60, 100 and
150 day intervals. The averaged results and percent change in test
BARRIER TECHNOLOGY 283
-------
property values are recorded in the tables.
There are no well-defined standards to determine if the results
from a Method 9090 type immersion indicate if the liner "passed"
or "failed." But, after examining the results in Tables 1 and 2, we
can make the following remarks. The sample specimens seem to
have stabilized in the dichloroethylene by the first sampling
period (60 days). For dichloroethylene, any reaction with the
HDPE appears to have ceased. In fact, the change may well be
due to absorption of solvent only, without chemical reaction.
These conclusions are confirmed by the results of thermal-
oxidative stability testing of the liner at the 60, 100 and 1 SO day in-
tervals of immersion. Thermal-oxidative stability testing is a con-
venient and practical approach to determine the extent to polymer
degradation in geomembrane liners. High temperatures and high-
ly reactive oxygen are combined in thermal-oxidative stability
testing in order to accelerate the reactions responsible for the
destruction of polymer bonding. If degradation has taken or is
taking place, then thermal-oxidative stability testing will indicate
a degraded condition in the sample because of reduced stability
to thermal-oxidative conditions.
Table 1
Tensile Properties Testing Over 150 Days of Immersion In
Dlchloroethylene
40 mi •»» AT 2]'c
TICU
ILOKOTIOJ C.1
—
Octroi
40 Oajrf
Z Ck«(*
too o«r>
Z Qua|*
150 0>r*
I Cko|>
TD
Coitrol
40 o«r«
Z ChMa«
100 Day*
Z OlMt*
150 o«r>
Z d>«|«
„,
Concrol
M 0«rf
Z Qun|«
100 t»r'
Z O>U|«
150 D.ri
zo»,.
ContfoL
40 O.yi
Z ClUA|«
100 Oayi
• Chaag*
150 D.,i
Z duaga
,„,
2391
-1.4
2511
-1.1
2512
-1.9
2MI
2129
-2.1
2457
-1.4
2111
-:.5
UDJ
2429
-7.2
2*23
-14.4
2544
"*'*
2>74
-9.1
litt
•i.6
2110
+11
11
17
+1]
17
+11
17
+13.3
11
It
+4.7
17
+13
11
1
(o an. mn a tat
11
17
+u
i)
•i)
17
•1) )
1)
17
+13
17
+1)
17
+1].]
STUPcni (PSI)
4191
l«0>
•I.I
m;
+7.6
441}
• 1.5
4141
5252
+1.
52M
•4.1
41U
•2.4
4511
4(07
+5
471]
•4.4
45J7
• 1.4
JI07
IUAJI
IIOXUTIOH (»
s:s
to)
155
+1.7
•00
•4.5
+11
Bt
tli
946
+15
190
+7.1
83]
3.)
9M
155
+1.3
T«ble2
Other Physical Properties Testing Over 150 Days of Immersion IB
Dichloroetnylene
Co«:fJl
M> 2.Mil
I.rot]
I.4111
.054-
.054-
It) ' .054*
TO .05«-
14
J7
MIGHT auxi a »'c
too
men auKi a K'C
:.tiu
2.71 M
.054-
.057-
.057-
.057-
4.7
t.i
2.U17 +4.3
2.7124 +4.1
mcprm auxi a 23'c
•i.i .057* <
mcprm omg « 5Q*c
+1.1 .Oia-
X.t .057-
TUJi HSlt-JiXt AT I3'C
+1.4
+1.1
-11 J
•17
31
I]
2.7710
l.MIO
.OST-
.057-
.057-
.0}7-
52
J)
taumci a we
M>
w
54
47
41
i.
-ii.]
•15
51
+1.4
H.I
-7.1
+13
-II. J
•13
racrou c »-c
-«.) to
a »'c
t.i
40
MD— S»mpk iftcanm initd in machine dinction of procat manufidure.
TD — Sampk fpecxmem tested to numeric directioa to proceu manufacture.
Table 3 displays results of thermal-oxidative testing of the pipe
grade quality copolymer HDPE liner during chemical immersion
testing at the intervals of the test. The OITs were run accord-
ing to instrument manufacturer recommendations. A small sam-
ple of copolymer LLDPE liner was also tested for thermal-oxi-
dative stability during chemical immersion alongside the HDPE.
Table 3
Chemical Resistance Comparison of Copolymer HDPE Liner lo
Copolymer LLDPE Lteer by Measuring Changes in Stability Toward
Thermal-Oxidadve Degradation
Dlc>l»ro«tlqrl«««
Central
M tar
loo »*}
ISO »w
naal I
LU71
15
M
M
+5.11
U
to
10
MD—Sample specimens tested in machine direction of process manufacture
TD—Sample specimens tested in transverse direction lo process manufacture.
1 OIT (Oudatlve Induction Time) determined by Differentia) Scannini Calorimocr 02WC
I icmofOj.
' Samples immersed in chlorinated hydrocarbon at 23 *C.
In thermal-oxidative stability testing, since the reactions of
polymer degradation are exothermic, rapid deterioration shows
up on a differential scanning calorimeter (DSC) as heat flows out
of the sample. The time at which these degradative reactions
occur in a run-away fashion is therefore visible on the DSC by the
heat released in the destructive reactions. The time which the
sample requires to reach this run-away state of degradation is
called the oxidative induction time (OIT). OIT therefore pro-
vides a convenient measure of how long the liner sample is able
to withstand thermal-oxidative stress.
The results of Table 3 indicated that the dichloroethylene does
not actually degrade the HDPE. The HDPE retained its thermal
oxidative stability in dichloroethylene. On the other hand, the
LLDPE appears to have been degraded in the dichloroethylene,
losing 55% of its stability. The importance of polyethylene resin
selection in the manufacture of high quality geomembrane bar-
riers was confirmed.
Because of their excellent chemical resistance properties,
HDPE geomembranes are prime candidates for barriers to con-
tain the toxic and hazardous wastes encountered in Superfund
projects.
284 BARRIER TECHNOLOGY
-------
SUPERFUND CLEANUP STRATEGY
Every Superfund site requires its own special considerations
before a cleanup strategy can be delineated. The goal, however,
in every case is to prevent the toxic waste from migrating.
Current barrier technology can offer a number of practical ap-
proaches to site cleanup. These procedures can be generally
classified into the following groups:
* Removal of the contaminated material off-site for contain-
ment in a RCRA-approved hazardous waste facility or treat-
ment/cleansing of polluted soils
• Construction of an RCRA landfill at or adjacent to the site for
transfer and proper containment of the polluted soil
• Construction of an impermeable cap and barrier wall for on-
site waste containment to prevent infiltration of surface water/
precipitation and the spreading of contamination to the sur-
rounding groundwater
Removal of contaminated material to a hazardous waste facil-
ity means the construction of increased capacity at RCRA-ap-
proved disposal sites.
Proper construction of a landfill at or adjacent to the Super-
fund site would also demand the double liner technology re-
quired by RCRA. All the considerations appropriate to haz-
ardous waste facility construction centered around the installa-
tion of two layers of geomembrane would apply. These con-
siderations are not unique to Superfund work and will not be
dealt with in this article.
The construction of caps and barrier walls for on-site contain-
ment of Superfund waste likely will be a frequent strategy in
cleanup work. The use of geomembranes for cap construction
has been well-proven over a good many years. Barrier walls are
now being made with geomembranes. Caps and barrier wall ap-
plications for Superfund work are discussed in some detail in this
article.
CAP AND BARRIER WALL CONSTRUCTION
USING GEOMEMBRANES
Superfund cleanup work at Nashua, New Hampshire, util-
ized a cap and barrier wall to meet a fast-moving plume of
groundwater contaminated with organic solvents including chlor-
inated hydrocarbons. The contaminant plume was moving at a
rate of about 2 ft/day when work began in 1982 and had to be
halted right away. The 20-acre synthetic cap was constructed with
an HOPE geomembrane liner, and the barrier cut-off wall was
made from a bentonite slurry extending down to bedrock and
ringing the site in an oval shape.
- fHOUMO SWVACl-
W«ll Location*
• HOPE *»rrl«r
FILL
AND
•(FUSE
V «»DO«
MATEHuCN
>umn—
(•EHTONITC)
I
I
- WHCT WO KM FILL
EXCAVATED TRENCH BEFORE
PLACEMENT OF THE LINER
CROSS-SECTION OF THE
TRENCH WITH LINER
Figure 4
Bentonite Slurry—HDPE Barrier Wall Combination
Figure 3
Schematic of Cap and Barrier Wall On-Site Containment System
for Superfund Projects
Figure 5
Barrier Wall Construction at Quincy, Illinois, with Gundline HD as the
Impermeable Layer
BARRIER TECHNOLOGY 285
-------
Figure 6
Completed Barrier Wall at Quincy, Illinois
Because of fractures in the bedrock and because of evidence
that the organic chemicals in the aquifer would tend to degrade
the bentonite by altering the mineral composition of the clay,
groundwater interception and treatment were implemented
through the use of pumps. Contaminated water is thus being
pumped out of the containment area, treated and reinjected so
as to flush out remaining contaminants. This innovative and
dollar-saving Superfund project at Nashua, New Hampshire,
likely is indicative of the approach to be used at many sites in the
future (i.e., cap and barrier wall construction with pumping of
contaminated water to lower the water table within the contain-
ment and remove pollutants).
Construction of caps for Superfund cleanup could utilize other
geosynthetics such as geonet for drainage of surface precipita-
tion above the impermeable geomembrane layer as well as geotex-
tile for separation of cover soil from the fluid flow zones.
HOPE geomembranes recently have found application in bar-
rier wall construction in addition to their normal application in
synthetic caps. The advantages they offer are apparent:
• Completely watertight
• Inherent flexibility to allow for settlement
• Suitable for installation in all types of soil
• Resistant to decay, microorganisms, rodents and chemicals
• Simple, installation procedures
A new technique of locking together entire rolls of HOPE
sheet is now available. The lock ensures a completely water-
tight joint to prevent leakage of contaminated groundwater. The
sheets of HOPE equipped with the lock can be slid into place
next to each other as a vertical barrier down to the clay/bed-
rock layer. They can be joined to a synthetic cap at the surface
for isolation and containment of the toxic waste. Fig. 3 shows a
schematic diagram of this approach. To create both inward and
upward hydraulic gradients, thus further ensuring non-migra-
tion of the pollution, the water table within the containment can
be lowered through the use of drainage wells. Contaminated
groundwater flowing into the drainage wells then can be treated
and separated, and the waste can be properly disposed.
Barrier wall construction with HOPE can be applied in con-
junction with bentonite slurry as depicted in Fig. 4. Chemical
resistance is improved compared to conventional slurry walls or
grout curtains. Barrier effectiveness can be monitored from be-
tween the double layer of liner. This is a significant advantage
since most barrier walls are installed through contaminant pluma
and contamination exists on both sides of the barrier making it
difficult to tell if the barrier is leaking.
Another route to barrier wall construction using geomem-
branes is that taken by Gundle Lining Construction Corpora-
tion at Quincy, Illinois in the winter of 1986. The problem in
this case was that a river was eating into a landfill; as a result,
stream bank stabilization and protection of the hazardous wastes
from stream inflow were required. Fig. 5 is a picture of the ap-
proach used.
A metal framed bin wall was lined with HOPE sheet on the
side facing the landfill. Free-draining soil was used as internal
backfill inside the retaining wall. Granular backfill for leachate
collection was placed outside the wall adjacent to the HOPE. Fig.
6 is a picture of the completed bin wall. This type of construction
could be modified easily for use in Superfund cleanup projects.
CONCLUSION
Containment of hazardous chemicals on the earth's surface it
and will continue to be necessary for some time to come.
For long-term quality in barrier technology, attention must be
paid to the barrier materials. Even apparently similar materials
can behave quite differently.
The suitability of high quality geomembranes as barriers in the
containment of hazardous waste has been and is continuing to be
demonstrated on a very wide scale. The adaptability of the pro-
ducts and construction techniques to many different situations is
continuing to prove their usefulness and is extending their appli-
cation to the highly important work of the Superfund.
REFERENCES
1. U.S. EPA. "Minimum Technology Guidance on Double Liner Sy*
(ems for Landfills and Surface Impoundments—Design, Commc-
tion, and Operation" 1985.
2. Kingsbury, G.L. and Truesdale. R.S., "Clay—Chemical Compttibfl-
ity and Permeability Testing." Proc. Annual U.S. EPA Katordi
Symposium. U.S. EPA, Cincinnati, OH, 1985.
3. Brown. K.W. and Anderson. D.C.. Effects of Organic Sorventt on
the Permeability of Clay Soils, Report for Municipal Environmental
Research Laboratory of U.S. EPA. Cincinnati, OH, 1983.
4. Anderson, D.C. and Jones, S.G., "Clay Barrier—Leachate Interac-
tion." Proc. National Conference on Management of Uncontnlltd
Hazardous Waste Sites. 1983.
5. Day, S.R., "A Field Permeability Test for Compacted Clay Linen,"
Master of Science Thesis, University of Texas, Austin, TX, 1984.
6. Leaversuch. R., "HOPE: Resin of Choice for Barrier Functions?,"
Modern Plastics, May 1986, 68-71.
7. Schnabel, W.. Polymer Degradation: Principles and Practical Appli-
cations. MacMillan Publishing Co., New York. NY, 1981.
286 BARRIER TECHNOLOGY
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A Construction Quality Control Program
For Sludge Stabilization/Solidification Operations
Gary J. Deigan
Larry G. Copeland, P.E.
Weston Services, Inc.
West Chester, Pennsylvania
ABSTRACT
A construction quality control (QC) program was developed to
monitor full-scale sludge stabilization/solidification operations
often implemented during remedial and/or final closure activities
at surface impoundment, storage pile and landfill disposal units.
The QC program presented consists of monitoring the perfor-
mance of a stabilization/solidification process involving the addi-
tion of a proportioned admixture (portland cement, cement kiln
dust, fly ash, lime, soil or combinations thereof) to the sludges,
thereby reducing sludge moisture content and enhancing struc-
tural stability of the waste material.
The QC program has been effectively implemented at several
major surface impoundment closures and remedial action sites
by utilizing a combination of technically recognized field con-
struction and geotechnical-testing methods adapted to determine
index properties, establish QC-criteria and provide reproducible
data. An overview of stabilization/solidification operations is
followed by a technical amplification of each principal element
of the construction QC program.
INTRODUCTION
The stabilization/solidification of hazardous and non-haz-
ardous sludges, contaminated soils and sediments often is deter-
mined from feasibility and value engineering studies to be a cost-
effective technology designed to improve physical and chemical
properties of waste materials, thereby enabling more effective
waste handling, containment, storage and disposal. Stabiliza-
tion/solidification has been technically recognized by state and
Federal regulatory agencies and throughout the industry as a vi-
able hazardous waste management technology for certain wastes
when utilized as a preliminary process for land disposal and land
containment. Applications of the process include:
• Industrial pretreatment and on-site waste processing operations
• Final dewatering/moisture reduction process at treatment,
storage and disposal facilities (TSDFs)
• Remedial action technology or pretreatment process for final
stabilization/solidification of waste materials during closure of
waste pits, surface impoundments, landfills and storage piles
The effectiveness of the technology depends primarily on the
ability of a proportioned waste admixture to provide solidify-
ing-stabilizing effects through improvements in physical and
chemical properties of the waste. The mechanisms which pro-
duce these improvements are waste and admixture specific; how-
ever, they usually are limited to sorption and/or hydration
through pozzolanic reactions. Characteristic improvements are
mainly in the form of moisture reduction, change in particle dis-
tribution and subsequent improved physical consistency and load
bearing capacity. Following a curing period, the resultant waste
product usually has a physical consistency representative of a
solid, dry mass more suitable for long-term containment in engi-
neered land disposal systems.
The stabilization/solidification process depends upon a num-
ber of significant design parameters, engineering and operational
considerations including:
• Determination of initial physical and chemical waste character-
ization
• Development of waste-specific admixture designs
• Methods of implementing full-scale stabilization/solidification
operations
• Physical and chemical characteristics of the stabilized/solidi-
fied waste materials
• Economics of the technology relative to other available tech-
nology alternatives
Variations during full-scale implementation in any one or more
of these design/engineering parameters can result in reduced
overall effectiveness of the stabilization/solidification technol-
ogy. The resultant stabilized/solidified waste material may be
characteristically less suitable for long-term containment and thus
create increased stress on the performance of the engineered land
containment/disposal system.
This potential occurrence, combined with increased utilization
of the technology and intensified emphasis now being placed on
quality control/quality assurance mechanisms, necessitates devel-
opment of a quality control (QC) program as an integral part of
the design and construction management tasks associated with
stabilization/solidification operations.
The purpose of this paper is to introduce a QC program devel-
oped from recognized construction management techniques and
from standardized soils and concrete test methods adapted spe-
cifically to monitor full-scale waste stabilization/solidification
operations.
The QC program draws on the experiences of developing waste-
specific admixture designs and monitoring the performance of
both full-scale batch process and in situ stabilization/solidifica-
tion operations implemented during closure of sludge-storing
surface impoundment units. Variations in the QC techniques
presented herein are dependent on the project scale, site-specific
conditions, implementation techniques and objectives of the tech-
nology application. The QC mechanisms should interest facility
owners and operators, resident engineers and inspectors, contrac-
tors and regulatory personnel.
STABILIZATION/SOLIDIFICATION
PROCESS OVERVIEW
The compound term stabilization/solidification, as used here-
WASTE STABILIZATION/FIXATION 287
-------
in, refers to waste treatment processes which are designed to
accomplish one or more of the following objectives:
• Improve handling and physical characteristics of the waste
• Decrease the surface area across which transfer or loss of con-
tained pollutants can occur
• Limit the solubility of or detoxify hazardous constituents con-
tained in the wastes'
Stabilization refers to the chemical interaction which may take
place within the process to render the waste material less haz-
ardous by converting contaminants to a less soluble and less
mobile, toxic form. Stabilization alone may not result in im-
proved or changed physical characteristics of the waste. Solidifi-
cation does not necessarily result in a chemical interaction which
detoxifies the waste material to any degree; however, it refers to
the physical characteristic improvements which take place
through addition of the waste admixture. Solidification accom-
plishes one or more of the above objectives by mechanically bind-
ing, fixating or encapsulating waste constituents into a mono-
lithic solid with greater structural integrity.
Stabilization/Solidification Techniques
Current methods used to achieve stabilization/solidification of
waste sludges, slurries, sediments and soils include:
• Absorption/adsorption
• Cement-based pozzolanic processes
• Lime-fly ash pozzolanic processes
• Encapsulation (micro and macro)
Each of these methods may be implemented as a single pro-
cess or in combination with physical/chemical pretreatment sys-
tems such as dewatering, waste blending, neutralization, oxida-
tion/reduction and chemical destruction.
Absorption/adsorption techniques mainly involve the addition
of a dry, solid, fine-grained material (soil, ash, kiln dust or syn-
thetic sorbents) to semi-solid and liquid wastes to reduce free
liquids and improve materials handling characteristics.
Cement-based pozzolanic processes utilize the properties of
Portland cement and cement production by-products (cement kiln
dust) to achieve the stabilization/solidification objective. The
high pH of cement-based waste admixtures provides stabiliza-
tion for many metal-bearing waste types by converting soluble
cations to low solubility hydroxides or carbonates. Additionally,
cementitious reactions produce a stiff to hard material consis-
tency which incorporates contaminants into a hardened material
matrix.
Lime-fly ash pozzolanic processes utilize the same principles
as cement-based admixtures to achieve stabilization/solidification
of waste materials. Pozzolanic reactions take place between lime,
fine-grained siliceous materials and water to produce a hardened
waste/admixture mass. As a result of its characteristically high
pH, lime also reduces solubility and toxicity of certain waste con-
stituents.
Micro- and macro-encapsulation techniques are less widely
used to accomplish solidification/stabilization due to high cost
and the need for specialized equipment and trained personnel.
In general, these methods involve isolating wastes within a jacket
of synthetic plastics or asphalt. The QC methods presented here-
in deal primarily with the more widely used pozzolanic processes
of stabilization/solidification.
Process Implementation Mechanisms
Stabilization/solidification techniques are typically imple-
mented utilizing in-place or batch processing methods to incorpo-
rate the admixture into the waste material. Generally, in-place
or in situ methods involve mechanical introduction of the waste
288 WASTE STABILIZATION/FIXATION
additive within the confines of a diked surface impoundment or
constructed mixing area. The waste/admixture combination then
is mixed in-place with earth moving equipment (hydraulic back-
hoe, dragline, clamshell or bulldozer). The mixed material is left
to cure prior to excavation and disposal, or the material may be
disposed in-place and capped with an engineered cover system.
Larger scale stabilization/solidification projects may use a
batch plant to obtain a homogeneous mix of waste and admix-
ture. This technique typically involves application of convention-
al (or slightly modified) cement mixing equipment or pug mill
operations. In this manner, the mixed materials normally are dis-
charged to a curing area prior to final handling and disposal.
Several proprietary methods and mechanisms are marketed to
implement the stabilization/solidification process. In most cases,
however, these are only moderate variations to the generalized
methods previously described and may serve to more economical-
ly or efficiently accomplish the mixing task.
STABILIZATION/SOLIDIFICATION
CONSTRUCTION QUALITY CONTROL
Principal elements of a comprehensive construction QC pro-
gram to monitor sludge stabilization/solidification operations in-
clude:
• Obtaining chemical and physical waste characterization data
• Performing bench/field pilot-scale testing
• Evaluating QC data relative to the objectives or specifications
of the technology applied
These QC elements are specified to: provide initial waste char-
acteristics (index properties) of the unstabilized/unsolidified ma-
terial; verify or finalize the waste-specific admixture design
through bench and field pilot-scale operations; monitor full-scale
operations for QC through inspection of equipment and opera-
tional processes, providing field documentation and record
keeping; conduct a combination of field and laboratory physical
tests to monitor changes in material index properties. Data gen-
erated by the QC program are evaluated in the field relative to
project-specific standards and work is accepted or rejected for
failure to meet the specified design.
The overall QC program is applied more rigorously to the in
situ or area-mix methods of stabilization/solidification often im-
plemented during closure of surface impoundments and unstable
landfill or storage pile areas. Several elements of the program also
can be effectively utilized to monitor QC during batch process-
ing operations.
Chemical Physical Waste
Characterization
Obtaining chemical and physical waste characterization data is
a preliminary step in developing the QC program. Chemical char-
acteristics of the wastes are essential to determine personnel safe-
ty considerations during handling, inspection and testing of pro-
cessed and unprocessed wastes. Additionally, chemical compo-
sition of wastes may be utilized to determined the presence of
chemicals which may interfere with the effectiveness of stabil-
ization/solidification .
Chemical characterization both before and after stabilization/
solidification also is utilized to provide significant information
on improved leachability and toxicity characteristics of the waste
materials. Obtaining new chemical characterization data, how-
ever, is not essential to implementing the QC program since
changes in physical characteristics of the wastes are utilized as
primary indicators of the applied technology's performance.
This paper, however, is not intended to address associated im-
provements in chemical characteristics as a result of the stabiliza-
-------
tion/solidification process, as these occurrences are primarily
waste-specific. On this subject, the reader is referred to appro-
priate references cited at the end of this article.
Physical characterization of wastes includes determination of
density, moisture content, solids content, Atterberg Limits and
compressive strength. These physical parameters define initial in-
dex properties of the unstabilized/unsolidified waste materials.
Utilizing these indices (adopted from their traditional use in geo-
technical and foundation engineering practice), a QC monitor-
ing program is designed to define reproducible changes in ma-
terial index properties and thus provide a criterion for field mon-
itoring stabilization/solidification operations. The task of physi-
cal characterization may be conducted during bench-scale stabil-
ization/solidification activities or as a preliminary field or off-
site laboratory activity. The following subsections provide gen-
eral definitions of the index properties utilized to monitor sludge
stabilization/solidification operations.
Density
The density of a material may be expressed in terms of a wet
unit weight or a dry unit weight. The wet unit weight includes
the weight of porewaters, free liquids and particle solids in a
given volume of waste and is utilized in the field and laboratory
to establish informative weight-volume relationships of the ma-
terial. The most significant use of this property is to determine
accurate waste/admixture proportioning which is essential to
maintain mixture quality control.
Moisture Control
By definition, moisture content is the ratio of the weight of
water in a volume of waste to the weight of solids which usual-
ly is expressed as a percentage. Monitoring changes in the mois-
ture content of the wastes provides a primary indication of the
effectiveness of the stabilization/solidification process. Improve-
ments in physical consistency, bearing capacity and stability of
the waste normally are contingent upon a substantial reduction in
moisture content.
SoUds Content
Solids content may be utilized as an indicator of significant
changes in waste composition. This index property often is used
to determine changes in physical waste composition during area-
mixing or in situ methods of stabilization/solidification. From
a QC viewpoint, changes in this value may serve to induce opera-
tional changes in waste/admixture proportioning to accommo-
date for a decrease in the solids content of the waste and achieve
solidification.
Atterberg Limits
Atterberg Limits are utilized to establish criteria to determine
and define various states of cohesive materials consistency rela-
tive to moisture content. Atterberg Limits are defined as the
liquid limit (LL), the plastic limit (PL) and the plasticity index
(PI) under ASTM designation D4318.
The liquid limit is taken as the moisture content at which a soil
(in this case, waste) can be rolled into a 1/8-in. diameter thread
before crumbling. The plasticity index is the numerical differ-
ence of the liquid and plastic limits and indicates the range of
moisture contents through which the material remains plastic.
Although these limits values have little direct meaning, correla-
tions have been established to relate these index properties to
other meaningful engineering index properties. The QC program
for sludge stabilization/solidification operations utilizes Atter-
berg Limits, in combination with other index properties, as a
mechanism to provide reproducible QC data.
Compressive Strength
Compressive strength (shear strength) is a measure of a ma-
terial's ability to withstand a load without causing overstressing
or shear failure. There are a number of technically accepted
field and laboratory test methods to determine compressive
strength. In terms of its applicability to the solidification pro-
cess, compressive strength can provide an accurate indicator of
resultant changes in a waste material's physical consistency.
Measured numerical values for compressive strength of stabil-
ized/solidified wastes are correlated to various physical states of
soil, concrete and rock in evaluating the effectiveness of the solid-
ification operation. Values for compressive strength typically are
expressed as an applied load per unit of surface area.
Table 1 summarizes the physical characterization tests and lists
technically accepted testing protocols to determine each of these
properties.
Bench/Field Pilot Scale Testing
Utilization of bench and/or field pilot-scale studies can pose
significant advantages to refining the overall system design, in-
cluding the construction QC program. Bench-scale test mixtures
can be utilized to verify or supplement the waste/admixture de-
sign, providing both visual and numerical observations in estab-
lishing QC criteria. Determining the physical index properties
before and after bench-scale stabilization/solidification can pro-
vide an idealized range of potential changes in measurable index
properties, curing times and associated physical consistencies
prior to full-scale or pilot-scale operations.
In the field, piloe-scale operations reduce uncertainties and re-
fine the process of implementing full-scale stabilization/solidif-
ication operations. Further waste-specific characteristics and ad-
mixture properties often are discovered during this activity, and
corresponding operational modifications (such as equipment re-
quirements, material handling methods and construction sequen-
cing) can be resolved. Pilot-scale studies also can be an effective
mechanism for full-scale quality control. Mixture ratios may be
altered due to previously unforeseen variabilities in waste uni-
formity, moisture content, admixture properties, stratified den-
sity or materials handling and equipment capabilities. Signifi-
cant experience also can be gained by equipment operators and
QC inspectors, in recognizing visual and textural changes in waste
characteristics at various curing intervals of the stabilization/
solidification technique.
Index Property:
Density
Moisture Content
Solids Content
Atterberg Limits
Compressive Strength
Table 1
Test Methods:
ASTM D2937
ASTM D2922
ASTM D2216
ASTM D3017
AASHTOT217
Pan Drying Method
U.S. EPA Standard Method for Settleable
Matter (Storet No. 5008G)
ASTMD4318
ASTM D2166
Pocket Penetrometer
Cone Penetrometer
Construction Oversight/Inspection
Construction oversight and inspection is an integral part of the
QC program for full scale stabilization/solidification operations.
Typical construction inspection techniques utilized to accomplish
this task include:
WASTE STABILIZATION/FIXATION 289
-------
Visually observing mixing methods
Monitoring waste/admixture ratios
Documenting curing intervals
Delineating curing areas
Determining material sampling and testing frequencies
Establishing directives to implement corrective measures in the
event of non-compliance with specifications
These QC tasks are conducted in addition to the field and lab-
oratory testing program detailed in the following subsections.
Field/Laboratory Testing Program
A field and laboratory testing program is utilized, in addition
to a planned system of construction inspection, to provide read-
ily implementable tests to determine changes in initial index prop-
erties brought about by the stabilization/solidification process.
Values for index properties derived from these tests then are
evaluated against acceptable ranges or design standards estab-
lished during bench and pilot-scale studies. In this manner, less
rigorous and more frequent field tests for significant index prop-
erties can be conducted and values used as indicators that the pro-
cess is achieving specified design criteria. Adherence to design cri-
teria then is verified on a periodic basis through supplemental
laboratory testing for design parameters (i.e., compressive
strength, free liquids determinations, moisture-density relations,
permeability).
Field Test Methods
Field testing methods utilized to determine initial index prop-
erties of unmixed sludges and monitoring changes in index prop-
erties of stabilized/solidified sludges include moisture content de-
terminations, density measurements and in situ compressive
strengths. Periodic moisture content determinations are taken on
both mixed and unmixed sludges to monitor variations in mois-
ture content caused by changes in waste uniformity and induced
by hydration during the curing process. Methods of determining
moisture content may include oven drying (ASTM 2216) or pan
drying.
Atterberg Limits of stabilized/solidified materials should be
determined at various intervals utilizing ASTM Method D4318.
This index property then can be utilized to provide correlations
between moisture content, curing intervals and physical consis-
tency.
Field density measurements may be conducted utilizing the
drive cylinder method to determine in-place density (ASTM
Method D2937). This value should be utilized in checking mix-
ture ratios and in evaluating density relative to optimum mois-
ture-density relations of the material.
Several field methods are available to determine initial
strengths and monitoring improvements in compressive strength
of mixed and unmixed waste materials. Pocket penetrometer and
cone penetrometer testing are utilized most often to provide a
rapid field estimate of compressive strength and as a secondary
verification of results obtained by laboratory unconfined com-
pressive strength testing (ASTM D2166). The QC inspector
should correlate field-determined moisture content, physical con-
sistency and estimated compressive strengths at various curing in-
tervals with laboratory-determined design parameters to provide
a timely indication of acceptable or unacceptable work relative
to project standards.
Laboratory Test Methods
A laboratory testing program can be utilized in conjunction
with field testing methods to determine conformance with design
standards and specifications. This program may be implemented
utilizing an on-site geotechnical laboratory equipped to conduct
physical parameters and an off-site analytical lab to analyze
chemical parameters.
Laboratory-tested design parameters for QC determinations
during stabilization/solidification operations may include:
Unconfined compressive strength
Permeability of compacted, solidified wastes
Toxicity testing
Free liquids determinations
Moisture-density testing
Unconfined compressive strength testing (ASTM D2166) is
optimally performed on 3-in. diameter by 6-in. length cylindrical
corings and remolded samples. Depending on the consistency of
the waste mixture, corings can be taken by the drive cylinder
method or by remolding freshly mixed materials into test cyl-
inders. Remolded samples should be taken only in those mix-
tures where the material consistency is at or near the liquid limit
as determined by testing or visual observations. In this instance,
samples can be molded into 3 in. by 6 in. cylinders, left to cure
for the specified design period and then extruded and tested for
unconfined compressive strength. This testing may be conducted
for a given mixture at various curing intervals to determine im-
provements in strength with curing time (i.e., 7,14 and 28 days).
Project-specific requirements may necessitate determining
waste permeability as a design parameter to evaluate the stabiliza-
tion/solidification process. This measurement can be made by
subjecting similar cylindrically molded samples or corings to fall-
ing or constant head permeability testing (ASTM D2434 or Corps
of Engineers Manual EM 1110-2-1906).
Toxicity testing can be used to determine changes in certain
chemical characteristics of stabilized/solidified waste through the
Extraction Procedure toxicity test or the Uniform Leach Pro-
cedure.
Free liquid content of stabilized/solidified wastes can be tested
using the U.S. EPA-specified paint filter test method. This deter-
mination has become increasingly important with recent landfill
liquid prohibitions under RCRA.
Moisture-density (Proctor Testing) is a soils test method to de-
termine relations between moisture content and various degrees
of density based on compactive effort. This testing is used to a
significant extent to monitor the placement of layered and com-
pacted fills. ASTM Method D15S7 is appropriate for conducting
this test.
QC Data Evaluation
Evaluation of QC data consists of:
• Interpreting changes in index properties and visual character-
istics of the waste materials during implementation
• Correlating these indices with design standards established dur-
ing bench and/or pilot-scale testing
• Directing corrective measures in a timely and economic man-
ner when index property tests are below expected values
• Accepting or rejecting work based on design parameter test-
ing and the objectives of the technology application
CONCLUSION
Stabilization/solidification techniques often are implemented
to improve chemical/physical waste characteristics prior to final
handling and disposal and to mitigate waste constituent releases
during remedial actions. The effectiveness of the technology
application depends upon a number of design and operational
parameters: (1) the ability of a waste admixture to react with the
wastes to accomplish stabilization/solidification and (2) a mech-
anism to physically incorporate the admixture into the waste ma-
terial safely, economically and efficiently.
A number of QC methods can be utilized to monitor the
290 WASTE STABILIZATION/FIXATION
-------
stabilization/solidification process and thereby ensure, with rea-
sonable certainty, that the objectives of the technology applica-
tion have been satisfied. Combinations of construction over-
sight/inspection techniques, bench/pilot-scale studies and physi-
cal/chemical test methods have been introduced as mechanisms
to implement a comprehensive QC program during stabiliza-
tion/solidification operations.
REFERENCES
1. Landreth, R.E., "Guide to the Disposal of Chemically Stabilized
and Solidified Waste," U.S. EPA, Office of Solid Waste and Emer-
gency Response, SW-872,1982.
2. Cullinane, M.J., Jr. and Jones, L.W., "Draft Technical Handbook
for Stabilization/Solidification of Hazardous Waste," Environmental
Laboratory, U.S. Army Engineer Waterways Experiment Station,
1984.
3. Northeim, C.M. and Truesdale, R.S., "Construction Quality Assur-
ance for Hazardous Waste Land Disposal Facilities—Public Com-
ment Draft," EPA/530-SW-85-021,1985.
4. Cote, P.L. and Hamilton, D.P., "Leachability of Four Hazardous
Waste Solidification Processes," Proc. 38th Purdue Industrial Waste
Conference., 1983,221-231.
5. Winterkorn, H.F. and Fang, H.Y., Foundation Engineering Hand-
book, Van Nostrand Reinhold Co., New York, NY, 1975.
WASTE STABILIZATION/FIXATION 291
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Considerations in Data Collection
For Evaluation of Source Control Alternatives
At Hazardous Waste Landfills
James A. Hill
Robert J. Montgomery, P.E.
Warzyn Engineering Inc.
Madison, Wisconsin
ABSTRACT
To design and construct effective leachate source control alter-
natives, one must determine the internal structure and moisture
conditions within a landfill. Test pits yield an excellent under-
standing of the structure of landfilled materials. Samples col-
lected from test pits allow a reasonable degree of certainty that
the material tested is representative of subsurface conditions.
In situations where waste is greater than 20 ft thick or where
leachate head wells will be installed, drilling and sampling in
refuse are routinely performed. Geophysical logging of boreholes
or leachate head wells can yield substantial data on the internal
structure of a site. The construction of leachate head wells can ef-
fect the leachate level observed in a well. Observed leachate quali-
ty can vary significantly with location and time. Data generated
through these investigations are useful in assessing the effec-
tiveness of various remedial alternatives.
INTRODUCTION
With the increasing number of landfill facilities being placed on
the National Priorities List, investigating landfills for evaluation
of source control measures is becoming increasingly important.
Reducing leachate (free liquid) production rates and collection of
leachate before release into the surrounding environment are im-
portant parts of remedial actions undertaken to mitigate releases
from controlled or uncontrolled hazardous waste facilities. Con-
ditions at each landfill are unique and require detailed site-specific
investigations into their structure and the character of the wastes
and liquids contained within them. Factors which can effect the
selection and performance of source control measures at a landfill
include:
• Presence and composition of daily and intermediate cover
layers
• Refuse moisture content
• Presence of perched leachate zones at intermediate cover/
refuse interfaces
• Chemical character of the leachate, including the potential
for multiphased leachate
• Leachate head levels
• Refuse permeability and porosity
• Homogeneity of waste, particularly presence of containerized
wastes or areas of special waste disposal
• Liner construction and composition
• Presence of granular material directly above the liner
Landfills are dynamic systems which can take up to 30 yr after
filling is completed' to reach an equilibrium where infiltration
through the cover equals leachate exfiltration. Exfiltration can
occur by removal of leachate through the collection system or by
leakage out of the base and sides of the landfill. Detailed investi-
gations of landfill interiors are necessary to properly design re-
medial measures. If it is not recognized that moisture inflow is
exceeding current exfiltration rates, measures to contain, collect
or treat leachate releases may be undersigned. A treatment sys-
tem's hydraulic or contaminant loads may be significantly in-
creased when the refuse reached "field capacity" (maximum
moisture-holding capacity) when average moisture inflow is
passed through the unsaturaled zone to become leachate.
During the past 15 yr, Warzyn Engineering has performed over
100 investigations at municipal, industrial and hazardous waste
landfills. Many of the investigations have involved evaluating and
monitoring leachate within waste materials in landfills. Some of
the methods and procedures for investigating landfills, developed
during the performance of these studies, are presented here. Ex-
amples from several sites are used to illustrate investigative prob-
lems and the effects data collection methodology can have on de-
signing source control remedial measures.
INVESTIGATIVE APPROACH
Investigating contaminant releases attributable to a landfill re-
quires documentation of conditions within the disposal area. The
appropriate approach to investigating landfill conditions is dic-
tated by the physical configuration and setting of the landfill and
the known types of waste materials accepted. Depending on site
conditions, some or all of the following activities are involved in a
landfill characterization study:
• Test Pits
• Refuse Drilling
• Leachate Head Well Installation
• Chemical and Physical Characterization of Wastes (from test
pits or borings)
• Geophysical Logging of Leachate Head Wells or Refuse Bor-
ings
• Leachate Head Level Monitoring
• Leachate Analyses
A detailed discussion of the methods used to safely investigate
the interior structure of landfills is presented below.
TEST PITS
Excavations into waste materials produce a cross-section of
disposal activities. Test pits give a more representative view of the
landfill structure than can be obtained from samples and cuttings
from borings. The wider cross-section exposed and the larger
amounts of material available for sampling can give site in-
vestigators greater confidence that the samples being collected
and analyzed are reflective of the overall composition of subsur-
292 WASTE STABILIZATION/FIXATION
-------
face materials. Test pits generally are excavated with a backhoe,
which usually limits the depth of investigation to 20 ft. Backhoes
with custom-built arms or draglines can be used to excavate below
20 ft, but hourly equipment costs increase substantially.
Prior to excavating the pits, a bulldozer can remove and
segregate cover materials. This material can be used later as a cap
when the pit is backfilled. By placing wastes on stripped areas, in-
advertent contamination of surface materials is avoided. At-
tempts to place excavated wastes on polyethylene sheeting have
been awkward and ineffective in containing potential con-
taminants.
Bulldozers or end-loaders are considerably more efficient in
backfilling excavations than backhoes and substantially reduce in-
vestigation time. If the possibility for release of airborne con-
taminants exists, it is imperative that equipment be present to
immediately fill the excavations if monitoring indicates that unac-
ceptable releases are occurring.
At sites where drummed waste burial is suspected, an experi-
enced backhoe operator may detect and remove drums intact.
When investigating suspected drum burial areas, overpacks for
containing ruptured drums and a small pump and/or adsorbent
for recovering releases should be immediately available.
Before initiating subsurface work, all parties concerned should
agree to the protocols and procedures to be used when drummed
wastes are encountered. Generally, recovery of drummed wastes
is not the primary goal of subsurface investigations. Once con-
tainerized waste is encountered during an investigative phase of a
project, it is advisable to define the extent of drum disposal areas
while minimizing drum contact and time spent on removal. If
large numbers of drums are present, recovery usually is limited to
those drums whose integrity have been compromised by the in-
vestigation. Large scale drum removal and containment is han-
dled best by qualified removal contractors as an emergency
removal or as part of site remediation activities.
Fig. 1 shows the location of test pits used to define subsurface
features at a landfill facility in southeastern Michigan. The site
was originally operated as an oil recovery facility, but the opera-
tion was closed after polluting local groundwater. Two oil ponds
*"•*—JL_ I FORMER C
TM
OIL POND
I Test Pit E.lenl
— Edge ol 01 Pond
01 Dlicharge Area
# Drum OUpocil Area
•"-— Eslenl of Landfill
Figure 1
Test Pit Investigation Program
Investigation of Oil Pond and Drum Disposal Areas within a Landfill
and a number of drum disposal areas subsequently were covered
with up to 20 ft of municipal refuse. Oil from the ponds was dis-
charging into small ponds downgradient of the site. Definition of
the ponds' locations and characterization of the materials
associated with them was part of the Remedial Investigation of
the site.
Based upon approximate locations obtained from aerial photo-
graphs taken when the site was active, 34 test pits were excavated
to locate the oil ponds and drum disposal areas and to generally
characterize refuse disposal at the site. Samples of sludge from the
bottom of the oil ponds and underlying contaminated soils were
collected for chemical characterization. Results from the test pit
program were used to design a network of monitoring wells on
and around the landfill to determine the extent of contamination
from the oil ponds and the drum disposal areas. Data collected
during the test pit program will be used to evaluate removal and
containment alternatives during the Feasibility Study.
REFUSE DRILLING
When refuse depths extend beyond the limit of available ex-
cavating equipment of where leachate head wells are required,
drilling in refuse is necessary to characterize the internal structure
of a landfill.
Methods
Typically, a truck-mounted rotary drill rig similar to those used
for groundwater monitoring well installation is used for refuse
drilling. The drilling contractor should supply a machine with
adequate power to perform the required drilling (minimum
CME-55 or equivalent). Air rotary equipment should be avoided
for refuse drilling because it enhances the rapid release of air-
borne contaminants.
Hollow flight augers are an effective drilling method in refuse.
They have the following advantages over wash boring methods:
• A continuous casing is provided to isolate zones of perched liq-
uids, without the time delays and expense of driving flush joint
casings
• Water does not necessarily have to be introduced into the bore-
hole. Clean water may be introduced if air monitoring indi-
cates potential health and safety concerns exist from venting
landfill gases up the augers. However, dry drilling makes de-
termining the leachate levels easier.
• A continuous return of cuttings up the outside of the augers
allows for more accurate logging of the borehole between
samples.
When drilling in refuse, impenetrable zones may be en-
countered, due to objects as diverse as bedsprings, refrigerators
or wood. Up to 25% of drilling footage in refuse is terminated
due to penetration problems, so estimated drilling footages
should be adjusted to reflect "false starts." If sufficiently high-
powered drilling equipment is provided, it is generally more cost-
effective to choose a lesser footage rate on all refuse drilling than
to pay a higher rate only on borings reaching the desired depth.
Sampling
Chemical analyses of waste or refuse samples provide data to:
• Characterize materials for removal actions
• Assess the compatibility of waste materials with barrier or
collection piping materials
• Assess long-term leaching and future releases
• Characterize source materials for endangerment assessments
The samples collected during drilling yield a relatively undis-
turbed portion of subsurface material for physical and chemical
testing. Parameters typically of interest include Atterberg limits
WASTE STABILIZATION/FIXATION 293
-------
(fine grained soils), moisture content, grain size and permeability
(shelby tube samples). All samples of fine-grained soils from im-
mediately beneath wastes should be evaluated for degradation of
the material (typically characterized by an increase in permeabil-
ity) by an immiscible heavier than water phase of leachate.'
Collecting data on refuse moisture conditions is important to
determine if leachate production in a landfill is at equilibrium. If
refuse above the observed saturated level within a landfill is near
field capacity, then most moisture infiltrating through the cover
will become a free liquid and will not be bound up in waste
materials. If waste materials are not at field capacity, a greater
portion of liquids infiltrating the landfill will remain as a free liq-
uid as the waste nears field capacity. With increased amounts of
leachate production, leachate head levels will increase and/or
leakage rates will increase. The difference in currently observed
versus projected leachate levels can significantly impact the design
of leachate collection, holding and treatment systems.
Collection of split spoon (ASTM D-1586)' or shelby tube
(ASTM D-1587)' samples during drilling operations can add valu-
able information on daily soil cover and liner conditions. Stan-
dard protocol1 calls for collection of samples at S-ft intervals;
however. S-ft sampling intervals may miss intermediate or daily
cover materials that are causing perched liquids.
When the exact configuration of cover layers is required, either
continuous sampling or sampling at S-ft intervals and geophysical
logging should be used. If a good correlation between geophysical
logging and sampling observations is obtained and samples are
not needed for physical or chemical testing, sampling many refuse
borings can be eliminated. When it is suspected that a clay barrier
is present beneath the waste or samples of the waste/native soil in-
terface are desired, continuous sampling should occur over the
last 5 to 10 ft of the boring. The exact depth is dependent upon
the investigator's confidence in available data on the depth to the
bottom of waste. The risk of liner penetration should be kept in
mind during sampling. Compromising the integrity of a liner can
subject the consultant to liability suits brought by the site owner
or third parties.
Geophysical Logging
Geophysical logging can be used to obtain additional data on
the subsurface structure and moisture conditions within landfills.
Below is a brief description of the logging which typically is per-
formed on refuse borings:'
• Natural Gamma Logging—will differentiate between clay rich
(daily and intermediate cover) and clay poor materials (refuse);
gamma logging may be inappropriate if sand or sandy silt was
used for cover; however, determination of cover configura-
tion is less important for coarser materials, since they are less
likely to impede liquid flow.
• Gamma-Gamma Logging—indicates changes in bulk densi-
ties of materials; cover materials typically have a higher density
than the surrounding refuse.
• Neutron Logging—will indicate moisture content; the probe is
sensitive to the hydrogen content of organic materials.
Refuse boreholes typically are logged with several methods to
confirm observations. Geophysical logging can be performed in
an open borehole before a well is installed or down a leachate
head well. However, the density of the steel and the hydro-
carbon content of the PVC must be taken into account in log
interpretation. Use of calibration test barrels is recommended
on a site-by-site basis. Logging before well installation will avoid
interpretation problems caused by well construction, such as
"kicks" caused by casing collars. If open boreholes are to be
logged, a commercial well logging firm should be employed with
heavy-duty equipment for raising and lowering the probes.
Without such heavy-duty equipment, probes may be lost if the
borehole has partial cave-ins. In addition, NRC licensing require-
ments virtually demand use of subcontractors for radiation log-
ging, due to experience requirements. Logging open boreholes
can result in substantial standby charges for the waiting periods
between drilling boreholes. It is not advisable, given the unstable
nature of refuse, to keep all the boreholes open and have them
logged at the end of drilling. If cased wells are logged, smaller
portable logging units can be used to effectively log the boreholes.
Geophysical logging can substantially improve the understand-
ing of the interior of a waste site. Fig. 2 presents geophysical log-
ging results from a leachate head well at a landfill in southeastern
Wisconsin. Adjacent to the three logs is the interpretation of con-
ditions based on the logging. The well was constructed so the S-ft
screen was set and sealed at the bottom of the refuse. The liquid
level observed in the head well was substantially below the level
where geophysical logging indicated continuous saturated refuse
started. All the leachate head wells were screened at the bottom of
the site and consistently underestimated the saturated waste
thickness.'
The logging &k° determined the cover and refuse sequencing.
Throughout the site, clay materials proportionately increased at
the bottom of borings due to consolidation of the refuse layer.
Two zones of perched liquids also were defined.
920
INTERPRETED
RESULTS GAMMA NEUTRON
DENSITY
730
COUNTS/SECOND
Figure 2
Geophysical Logging Results
294 WASTC STABILIZATION/FIXATION
-------
LEACHATE HEAD WELL INSTALLATION
Approach
Leachate head wells can be screened at different depths within a
landfill. Prior to well installation, the investigators should have a
clear understanding of the ramifications of the type of well con-
struction used. Below is a summary of the three main types of in-
stallations and how their construction may affect data collected
from the well. Diagrams of each type are shown in Fig. 3.
Wells Screened and Sealed at the Bottom of the Waste
Wells constructed in this fashion act as piezometers, with the
leachate level noted representing the piezometric surface at the
bottom of the landfill. The observed leachate levels can be con-
siderably below the saturated refuse level, if saturated refuse is
relatively thick and leakage is occurring out the bottom of the
site. Analytical results of samples collected from a well sealed at
the bottom of the refuse may be reflective of an immiscible
heavier-man-water phase in the leachate. Leachate quality results
should be considered only representative of the interval in which
the well is screened, and not overall site leachate quality.
Wells Screened at the Bottom of the Waste
Wells constructed in such a manner with sand pack extending
to near the observed saturated level will probably provide a repre-
sentative measurement of the leachate head level within refuse.
Care should be taken so the sand pack does not extend into the
perched leachate pockets, possibly overstating leachate levels at
the base of the site. Wells with saturated sand packs which extend
considerably above the well screen may not detect any floating
phase leachate. Wells with screens which extend over the entire
saturated zone typically are not used due to the cost of the well
screen.
Wells Screened at the Top of Saturated Zones
Wells situated near or at the top of saturated sequences are a
good indicator of the saturated level of leachate within a landfill.
If a well is installed in a perched saturated zone, care should be
taken not to rupture the layer perching the liquids. When thick se-
quences of saturated refuse are present, a well screened at the top
of refuse may be installed in conjunction with either of the two
well types discussed above.
COVER
REFUSE
. V
~
0
SATURATEC
REFUSE
1
.
)
*• r*
;
f 1
:•
11 £
o |
— pi
; ;
't
if ;
I ^
1 /
\ ;
!
'•>
-------
basis (not filtered), paniculate matter in a sample can significant-
ly affect leachate quality results. The use of a fine grained sand
pack limits the use of the leachate head wells for horizontal
permeability testing. In high permeability zones, the maximum
permeability detected may be limited by the permeability of the
well screen filter.
The screen pack's grain size should be determined by the in-
tended use of the well and not necessarily by the suspected particle
size of the surrounding materials. When leachate head wells will
be used for permeability and leachate quality testing, a coarse
sand (0.7 mm) has been a good compromise.
Distribution of Wells
The vertical and horizontal distribution of leachate head wells
is ultimately determined by the investigator's confidence in the
homogeneity of the site. It is advisable that each distinct phase or
area of a site be instrumented with leachate head wells. At a
minimum, on a site where no detailed engineering plans are
available and little or no data are available on the waste structure
or leachate characteristics, one leachate head well should be in-
stalled for every 5 acres of fill area. The number of nested (multi-
ple level) wells installed depends on the depth of saturated refuse.
Where a saturated thickness of 20 ft above the top of the well
screen is detected, it is advisable to install more than one well.
Table 1 contains average values of indicator parameters from
leachate head wells installed in a 12-acre municipal landfill in
northwestern Wisconsin. The head wells were installed at essen-
tially random locations equidistant along the longitudinal axis of
the site. The apparently anomalous analyses for head well number
two (LH-2) were confirmed with subsequent analyses. Interviews
with local citizens and previous site operators indicated that the
well probably was located where open burning was conducted un-
til the late 1960s. The area used for burning was bermed off from
other sections of the site, allowing a pocket of unique quality
leachate to form.
Table 1
Average Leachate Quality at a Landfill In NW Wisconsin
Parameter
Well Designation
Conductivity
Total Alkalinity
Chemical Oxygen Demand
(COD)
Chloride
Total Hardness
Dissolved Iron
LH-1
6338
1638
3048
1293
1965
122
LH-2
260
47
51
43
69
0.005
l.H-3
4425
1328
2506
856
1593
35
Rttulu in mg/1 except conductivity, which ii in umhot/cm
Investigators need to consider the time frame of leachate
sampling during a Remedial Investigation. Fig. 5 shows changes
in indicator parameters for leachate from a collection manhole at
a large engineered landfill in central Wisconsin. The variability in
indicator parameters seen at this site and others implies that in-
vestigators need to seriously evaluate how representative their
data are of long-term leachate quality. Potential variability in
leachate quality must be factored into evaluations of leachate col-
lection and treatment alternatives and subsequent designs.
I
ft
TIM (r>«r»)
coNoocrivn-r
Figure 5
Leachate Quality in a Landfill Collection System
CONCLUSIONS
• Test pits are a relatively inexpensive and effective method to in-
vestigate waste disposal areas where waste does not exceed
20 ft in thickness.
• Refuse drilling, when used in conjunction with standard sam-
pling methods and/or geophysical logging, can provide a good
indication of the internal structure of a landfill.
• The construction of leachate head wells can effect observed
leachate levels. Leachate head wells can substantially under-
estimate the depth of saturated refuse.
• The location of leachate head wells and sampling time frame
can impact the observed leachate quality.
REFERENCES
I. Rice, J.M., Voorhees, M.L and Ohehe, A.C., "Use of Cdl Model in
Predicting Liquids Movement and Levels in a Landfill Site," Pnc.
National Conference on Management of Uncontrolled Hazardous
Waste Sites, Nov. 1985, 182-188.
2. Anderson, D.C.. Brown, K.W. and Green, J., "Effects of Organic
Fluids on the Permeability of Clay Soil Liners," Land Disposal of
Hazardous Waste, U.S. EPA Report No. EPA-600/9-82-002, 1982,
179-190.
3. American Society for Testing and Materials, D 1586-84 Penetration
Test and Split Barrel Sampling of Soils, 15-1587-83 Standard Practice
of Thin-Walled Tube Sampling of Soils, Annual Book of ASTM
Standards, Volume 04.08, 1985, 298-307.
4. Montgomery, R.J., Wierman. D.A., Taylor, R.W. and Koch, H.A.,
"Use of Downhole Geophysical Methods in Determining the Internal
Structures of a Large Landfill," Proc. Eighth Annual Madison
Waste Conference. 1985, 559-569.
5. Warzyn Engineering Inc., "Caisson Analysis Report," 1985.
296 WASTE STABILIZATION/FIXATION
-------
Fixation/Solidification of Hazardous Waste
At Chemical Waste Management's Vickery, Ohio Facility
Michael F. R. Curry
Chemical Waste Management, Inc.
Vickery, Ohio
ABSTRACT
Chemical Waste Management, Inc. is ceasing treatment of
hazardous/toxic wastes in open surface impoundments at the
Vickery, Ohio, Facility. The lagoons are being closed and wastes
which are highly acidic are being neutralized and chemically fixed
with dolomitic quicklime and cement kiln dust. This fixed material
then will be placed in a secure landfill.
The paper describes the reagent selection and the procedures and
methods used to solidify the toxic sludge which produced 250,000
yd of fixed material. The design of the landfill to hold the hazard-
ous material also is described.
INTRODUCTION
The Chemical Waste Management site at Vickery, Ohio, is
located six miles east of Fremont, Ohio, on State Route 412. The
248-acre site is bounded by the turnpike to the North, State Route
412 to the South, State Route 510 to the East, and County Road
244 to the West. Only about 97 acres are used for the waste disposal
operations; the remaining land is farmed (Figure 1).
Figure 1
General View of Chemical Waste Management, Inc. Site, Vickery, Ohio,
Showing Surface Impoundments to be Closed.
The Site originally was started by a local resident in 1964 for
the purpose of oil recovery. In order to "crack" the oil emulsions,
acid was required. For economic reasons, waste acid was used and
this led to the construction of surface impoundments in 1970 to
hold this material. From those early beginnings, the site developed.
By 1971, five lagoons existed.
The first deep well permit was obtained in 1975, because disposal
by evaporation was considered an unacceptable method of disposal
by the authorities. Four deep wells had been permitted by the time
Chemical Waste Management, Inc. purchased the site in 1978. Two
further wells have been installed since that time.
In early 1983, PCBs (less than 500 ppm) and dioxins were found
on-site in three of the surface impoundments. The Company, in
negotiations with both the State of Ohio EPA and the U.S. EPA,
decided to close all five surface impoundments that remained on-
site. Because the controlling regulations for disposal would be the
PCB regulations promulgated under TSCA, the available options
permitted were limited to disposal in an approved landfill, incinera-
tion in a U.S. EPA-approved incinerator or disposal via some
alternative methods approved by the U.S. EPA Regional Adminis-
trator. A risk assessment study was undertaken which showed that
off-site disposal with the large volume of material and distance
to an approved disposal site posed a greater risk than on-site
disposal. It was, therefore, decided to develop a plan to stabilize
and fix the material and dispose of it in an on-site closure cell,
which would be acceptable to both the U.S. EPA and the Ohio
Environmental Protection Agency (OEPA).
This proposal was further influenced by the natural soil con-
dition of the area, which comprises a very low permeability clay.
The area, which is rural, requires the installation of extensive land
drainage systems by local farmers.
CLOSURE PLAN
The initial concept for closing the impoundments was fairly
simple and straightforward. There was excess land on-site where
a land cell could be constructed and site personnel had solidified
pond sludges in the past utilizing a mixture of sugar beet tailings
and lime kiln dust.
However, as discussions with the U.S. EPA developed, it became
clear that a restriction on the closure cell was likely to be imposed.
For a variety of reasons, the U.S. EPA required that any closure
cell constructed at the site for the disposal of fixed material from
the ponds should occupy the same location that initially was
occupied by the three impoundments containing the PCBs.
Because of this, an additional restriction resulted: the volume
of material the closure cell could hold was limited by the plan area
of the three ponds and a restriction on the height to which the cell
could be filled. Any reagents used for the fixation process would,
therefore, have to keep "bulking" to a minimum.
SELECTION OF REAGENTS
Battelle-Columbus Laboratories were retained to evaluate a
variety of solidification agents. Eight various combinations were
used (Table 1), and evaluated on the basis of the Extraction Pro-
cedures toxicity test as described in the Federal Register, May 19,
1980; in addition priority pollutants PCBs, and 2, 3, 7, 8 tetra-
chlorodibenzo-/»-dioxin (2, 3, 7, 8-TCDD) were measured. In
addition to assessing the efficiency of fixation, "bulking" of the
resultant fixed material also was assessed.
Samples of unfixed sludge and fixation materials were subjected
to extraction and analysis for the contaminants mentioned above,
WASTE STABILIZATION/FIXATION 297
-------
using U.S. EPA protocols. For each system, the effectiveness of
the stabilization alternatives were compared in what was the relative
attenuation of the contaminants. Analyses of the samples were
reviewed and compared.
None of the three contaminant compounds found in the pond
sludges and deemed particularly important at the outset of the
study, namely 2, 3, 7, 8, tetrachlorodibcnzo-p-dioxin (dioxin),
polychlorinated byphenyls (PCBs) and dichlorobenzidine (DCB)
were detected in any of the leachates generated.
Table 1.
Composition of Sludge Fixation Alternative*
(All Parts on a Weight Basis)
System I
100 parts sludge
.15 pans cement kiln dust
40 parts sugar beet lailmgs
15 parts steel pickle liquor
System II
100 parts sludge
20 parts cement kiln dusi
60 parts clean site clay
System III
100 parts sludge
20 parts cement kiln dust
30 parts fly ash
30 pans calcium sulfate sludge
System IV
100 parts sludge
30 parts cement kiln dust
20 parts calcium sulfate sludge
System V
100 parts sludge
30 parts cement kiln dust
20 parts Portland cement
System VI
100 parts sludge
20 parts cement kiln dust
20 parts beet tailings
20 parts Portland cement
System Ml
100 parts sludge
15 parts quicklme (calcium oxide)
System VIII
100 parts sludge
1 5 pans quicklime
20 parts cement kiln dust
From a leachate quality standpoint, Fixation Systems I, II, VI,
VII, and VIII generally produced very good and virtually equivalent
results for the Vickery sludge [I]. System HI leached significantly
greater quantities of lead, while IV and V afforded the poorest
performances of all the systems tested.
Volumetric tests on the various systems showed significant varia-
tions on fixation (Table 2).
With the restriction on volumetric capacity in the closure cell,
clearly Systems VII and VIII had advantages over the other systems.
Another factor considered which influenced the final decision
on system selection was the availability of reagent material. Sugar
beet tailings which were utilized in System I and VI proved to have
limited local supply and were very seasonal. This, in effect, elim-
inated these systems, while the bulking factor eliminated System il.
Material for Systems VII and VIII was then subjected to strength
Table 2.
WMIC Volume Increase for Fixed Sludges
System
I
II
ill
IV
V
VI
VII
VIM
Volume Increase It
56
47
47
(Not Tc»lcd)
19
26
9
21
and consolidation tests [2). These showed that with both samples
there was a high initial compression and relatively low consolida-
tion compression (Table 3).
Table 3.
Volume Change* with Single Load Increment or 3600 Ib/fl1
Total Volume Decrease (r«)
Volume Detrea« Due To Inilial
( ompreMion (**•(
Fluid Drained ("• of original »eight)
Increase In Density (r«l
12 I
70
5 9
7.1
7.3
55
0.8
7.1
Both materials exhibited measurable secondary compression but
only equated to a settlement of 2-4 in. over a period of approx-
imately 100 yr on a 45-ft high cell.
Because of the lesser bulking of the calcium oxide, it was decided
to utilize this mix, but add limited cement kiln dust to reduce con-
solidation and fluid leachate. A mixture of 100 pans sludge to 15
parts calcium oxide and 5 pans cement kiln dust was selected.
FIELD EVALUATION
Having approved the constituents for the reagents and accepted
the results obtained in the laboratory for fixing the pond sludges,
the U.S. EPA required proof of the results in a field trial.
At the site, a small pond (approximately 180 ft x 85 ft) containing
some 2000 yd of sludge, was designated to be treated as a pilot
project.
This project was used to determine three things:
• Could the results obtained in the laboratory be reproduced
in the field and would the fixed material have acceptable
structural strength?
• How could the additives be applied to minimize dust
generation?
• Could the material be mixed satisfactorily with back-hoes?
For the pilot project, super bags were filled from a silo with the
Figure 2
Storage Bins for Reagent Storage During Closure Operations
with Dust Collectors in Position.
298 WASTE STABILIZATION/FIXATION
-------
ilcium oxide and cement kiln dust. The weight per bag varied from
000 to 3000 Ib, and these were placed on the sludge using a crane
o support the bag approximately 6 to 12 in. above the surface.
lie pilot project showed that this method of dispensing the reagent
ras practical and that mixing with a back-hoe was possible and
induced satisfactory results.
The pilot project took three weeks to complete working 12
ir/day. Based on the pilot project experience, it was decided that
wo shifts should be worked on the main project.
SITE PREPARATION
Because the U.S. EPA required the closure cell to be located
in the same area occupied by the ponds, a temporary stockpile area
for the fixed material had to be constructed.
This requirement meant that significant construction work had
to be completed prior to the commencement of any operation. The
stockpile area, approximately 6 acres in size immediately east of
the ponds, had to be prepared by lining the area with a minimum
of 3 ft of clay and providing a retention area to contain precipi-
tation run-off from the stockpile. The capacity of the retention
area was to accommodate a 24-hr, 25-yr storm. Three quarters of
a mile of fence line was erected to isolate the operational area from
the rest of the site. Separate areas were established for personal
and equipment decontamination, both having their own water
supply and wastewater disposal systems.
Because of concerns about dust (the reagent material was of 16
mesh and below), a dust collection system was installed at the point
of discharge to the storage pigs. Storage pigs (Figure 2) were
employed to ensure that any failure of transportation or factory
production could be accommodated for up to 3 days.
In addition, lighting was installed on the entire 12-acre site, im-
poundment and stockpile areas to provide background lighting for
the night shift who utilized mobile lighting sets for point lighting
(work area lighting).
It already has been mentioned that, during the pilot project, super
bags were used. Because these bags sustained damage and often
were not reusable, it was decided to manufacture reusable
dispensers to dispense the anticipated 20,000 tons of reagent. Each
dispenser could hold approximately 4,500 Ibs, could be loaded
pneumatically, had a dust control facility and could be unloaded
mechanically and remotely. Because of the volume of reagent, eight
dispensers were manufactured and used throughout the project.
Prior to startup, two further tasks had to be accomplished. The
first was the installation of weigh scales to control the weight of
reagent dispensed. The second was to train all personnel in the use
of self-contained breathing apparatus and all aspects of the safety
rules, regulations and operating procedures.
POND CLOSURE
The three ponds to be closed (Ponds 4, 5 and 7) were each
200ft wide and 800 ft long. The ponds had been surveyed in 1983
in an attempt and estimate the depth of sludge. The best estimate
that could be obtained indicated that the depths were likely to be
3 ft in Pond 7, 8 ft in Pond 5 and 14 ft in Pond 4. A portion of
Pond 4 had also been closed previously; included in the Closure
Plan was the re-opening, excavation and fixation of the material
in the previously closed section.
Because it was not known what problems were likely to be
encountered, it was decided the fixation/solidification process
should take place in Pond 7 first as it contained the least amount
of sludge.
The supply of reagent was contracted with three different sup-
pliers. Two quick lime suppliers were used, as a single supplier could
not supply the total volume necessary. Use of two suppliers also
provided an alternate source in case of factory breakdown. Only
one supplier was used for the cement kiln dust. The additives were
delivered in bulk, using tankers which discharged their loads
Pneumatically into the eight storage pigs, each of which held
between 100 and 150 tons. Six pigs were reserved for the calcium
°xide and two for the cement kiln dust.
From the storage pigs, the reagent material was pumped
pneumatically into the reagent applicators. During this operation,
the applicators were placed on scales so the reagent could be
weighed as it was loaded. Weighing was necessary to determine
and maintain the mixing rates in the pond.
The plan for the actual mixing operation utilized two cranes,
each with a 100-ft boom. One crane sat on the East dike and one
on the West dike to dispense the reagent. The cranes were rigged
with double cables, one supporting the applicator and the second
enabling the crane operator to activate the lever to operate the clam
shell gate at the base of the unit and deposit the reagent.
As three back-hoes were used in the mixing operation, each crane
served one and a half hoes. To simplify the reagent application,
the applicators were numbered "1" through "8"; "1" through
"6" were filled with quicklime and "7" and "8" with cement kiln
dust. This mechanism maintained the 3:1 ratio for the fixation
recipe. To make things even simpler, odd numbered applicators
were used on the West dike and even numbered applicators on the
East dike.
The applicators were pneumatically loaded while connected to
both the pigs and a dust control system, which was located beside
the scales. The weight of reagent in each applicator was recorded
before the applicator was picked up and transferred by a forklift
to the cranes. The cranes moved the applicators over the sludge
and deposited the reagent, utilizing their second cables to control
the quantity of material deposited (Figure 3). If the chemical
Figure 3
Crane Depositing Cement Kiln Dust on Sludge with Back-hoe
on Right Mixing in Calcium Oxide.
Figure 4
Back-hoe Outloading Solidified/Stabilized Sludge onto Dump Truck.
WASTE STABILIZATION/FIXATION 299
-------
reaction between the sludge and reagent became strong, the quan-
tity of reagent deposited was reduced. The crane operator varied
the quantity of reagent applied as required by the prevailing con-
ditions in order to control heat and dust generation.
Once the reagent was deposited, the back-hoes started mixing
with a "kneading" action. As soon as solidification started, the
solid material was used to form a dike around the mixing area.
Additional reagent then was placed in the mixing area and mixing
continued until solidification and fixation were completed. Com-
pletion of fixation was determined using the following criteria:
• Visual inspection (the material to be solid and earth-like)
• No free liquid
• Possible to excavate with back-hoe (material sitting in bucket
and not flowing over edge)
• Holding angle of repose of 30-45° when stockpiled
• Maintain a ratio of reagent/fixed material of 1 /6 or 0.13-0.16
The material then was excavated and cast to the rear of the back-
hoes. The dike then was broken to permit an inflow of additional
sludge. This process was repeated until sludge ceased to flow to
the hoes. The back-hoes then moved out onto the fixed material
using crane mats. This process was repeated until each pond was
fixed.
Once the material had been fixed and cast behind the three mixing
back-hoes, a fourth hoe on the dike loaded the materials into trucks
(Figure 4) for transport to the stockpile area. As the back-hoes
moved along the bottom of the pond, a bulldozer was used to feed
the material to the fourth back-hoe which then loaded it onto trucks
for disposal in the stockpile.
The sludges in all three ponds took just under 5 months to
solidify and fix, utilized approximately 20,000 tons of reagent and
produced about 170,000 yd1 of fixed material. Once all the
sludges had been removed, the previously closed portion of Pond
4 was excavated material fixed where necessary and stockpiled. A
further 70-80,000 yd1 of material were removed and 2,000 tons
of reagent were used.
Once all the fixed material and the southern half of Pond 4 (i.e.,
the previously closed portion) had been excavated and stockpiled,
there was a requirement to ensure the remaining clay was clean.
This requirement was met by excavating at least 6 in. of clay and
transporting it to the stockpile. Tests then were run on samples
of soil, and excavation continued until the area was shown to be
clean based on laboratory results. Depths of excavation varied by
the time clean conditions were reached. These were generally
between 6 and 18 in. but in one location reached 3 ft. The most
difficult contaminants to remove were the heavy metals.
All the material excavated produced a stockpile approximately
46 ft high and measuring 620 ft x 460 ft (Figure 5). One plan
requirement was that the pile should be covered. The initial con-
cept was to utilize gunnite but because of the size of the stockpile,
a gunnite cover would have cracked extensively unless the cover
had been constructed with significant thickness and included rein-
forcement. An asphalt cover also was considered. Finally, a
polypropylene cover was selected and approved by the OEPA, but
a restriction on the number of separate sheets utilized was imposed
by the U.S. EPA. The restriction was eight sheets. A cover was
placed on the stockpile using the required eight sheets, but these
were lost in gale force winds of over 55 mi/hr. soon after instal-
lation. The cover has been redesigned utilizing 53 sheets—12 ft wide
and of varying lengths. This construction has proved to be much
more satisfactory and has been in place for the last year.
The stockpile retention area contains all the runoff from the
stockpile and has a capacity of approximately 1.5 million gal. In
order to dispose of the volume of liquid in the retention area, a
pipeline was installed to discharge the liquid to the two remaining
surface impoundments (Ponds 11 and 12).
SAFETY
Throughout the entire fixation process, safety was of the utmost
importance. It already has been stated that a training course for
personnel was held prior to the start of operations. In addition
to instruction in the operation and use of breathing apparatus
(Figure 6), instruction also was given on potential hazards, first
Figure 5
Stockpile (in upper picture) with Runoff Retention Area.
Call Construction Starting (in foreground).
Figure 6
Workers Wearing Full Personnal Protective Equipment.
aid, safety equipment locations, both project and site contingency
plans and last, but by no means least, dressing, undressing and
decontamination procedures.
Apart from the personnel aspects of safety, both air monitoring
and monitoring of decontamination procedures were undertaken
extensively. With regard to air quality, three different aspects were
monitored. These were:
• Perimeter monitoring; i.e., air at site boundary
• Organic vapor analyses monitoring within the operational area
• Monitoring of operational personnel
MONITORING
Perimeter Monitoring
Monitoring was undertaken to measure the air quality at the
perimeter of the site and to see if there was any significant increase
of contaminants in the air during mixing. In order to establish a
base, air samples were taken prior to the commencement of any
operation to measure the level of contamination existing in the air,
to determine what those contaminants were and to establish
background readings.
Further samples were taken over weekly periods during the fix-
ing operations in Ponds 4, 5 and 7. The results showed that there
was a slight increase in air contaminant levels during the fixation
300
WASTE STABILIZATION/FIXATION
-------
process. These levels were well below a level, of concern, but did
show an increase as the fixation process went from Pond 7 to Pond
5 to Pond 4. This increase was expected and would seem to in-
dicate that the fixation of the remaining ponds will produce even
less air-borne constituents than already have been experienced.
OVA Monitoring
The level of protection employed by the workers was determined
by monitoring at 16 discrete locations within the operational area
with an Organic Vapor Analyzer (OVA). This device was read at
each location prior to start-up. Throughout the entire operation,
which lasted approximately 6 months, readings on the OVA were
taken twice per shift, every shift. By reviewing these readings, the
level of protection to be afforded the men was determined after
consultation between the Project Manager and Safety Officer and
Industrial Hygienist.
Personal Monitoring
Finally, to supplement all of the above data, personal monitoring
devices were worn by 20% of the work force during each shift.
These devices monitored 16 constituents and gave an indication
of the level of contamination in the work area. These results, in
turn, could be correlated with the OVA readings. The collection
tubes were analyzed on-site with a 24 hr turnaround time.
CLOSURE CELL
The basic TSCA requirments for a toxic landfill are fairly
straightforward. There should be a 50-ft separation between the
cell and groundwater, and the material should be sealed from the
surrounding area by a clay liner with a minimum thickness of 3
ft and a maximum permeability of 10~7 cm/sec.
The TSCA land cell designed for Vickery is much more
sophisticated than the requirements require and has been evolved
over the past 2 yrs after considerable discussion between the U.S.
EPA and the Company and redesign by our geological consultants.
The geology of the site is good, as was demonstrated by the depth
of soil contaminated in the surface impoundments. Remembering
that the impounded material was highly acidic and was present in
the impoundments for some 15 yrs, the penetration was minimal.
Any form of liquid penetration in the same area is difficult. The
area always has significant ponding of water, and farmers have
to employ extensive land drainage schemes. The main aquifer is
also between 50 to 600 ft below ground surface. It was because
Figure 7
Vickery Closure Cell—Double Liner Schematic
of this geology that there was the possibility of building the land
cell on-site. However, it was stipulated that the disposal area should
be accommodated within the area previously occupied by the
ponds.
The first problem encountered with the cell design was to obtain
the 50 ft differential between the groundwater and the cell base.
Because the area is flat and virtually non-permeable, groundwater
is at-grade. It was requested that a variance from the 50-ft separa-
tion from the aquifer be granted and a 2-ft thick gravel capillarity
barrier be installed below the cell in order to prevent any upward
migration of the groundwater. Water entering this capillarity barrier
or drain would be collected and pumped to a holding tank. Liquid
collected in the tank would be tested and either disposed of through
the deepwell system or discharged into the surface water system,
depending on its quality.
A variety of designs for the cell were submitted, and these have
been reviewed over the last 2 yrs. The final design (Figure 7) is
probably the most advanced for any form of land cell.
Immediately above the capillarity drain or barrier, compacted
clay will be placed and shaped for the gradients for the ultimate
leachate collection systems. The gradients to be installed, which
will create collection points at the north and south edges of the
cell, are significant, being in excess of 2%. Because the cell length
is just under 800 ft, 8 ft of clay need to be placed at the center
of the cell to provide satisfactory gradients.
Above this contoured clay will be a 2-ft clay liner. QA/QC for
installation will have a much tighter specification than for the con-
tour clay, and routine field testing will be conducted to ensure a
permeability of less than 10~7 cm/sec.
Above the clay liner will be two 60 mil HOPE liners. Each liner
will have its own leachate collection system and sump (Figures 8
and 9) together with pumps and ancillary equipment to extract any
leachate that may collect. Filter fabric will be used on either side
of the liners to protect them during installation.
QA/QC procedures on the liner system will be strict and con-
ducted by an outside consulting firm. QA/QC control for the liner
will not be restricted to the installation process only, but will in-
clude both manufacture, storage and transportation. During the
installation of the liners, inspection and non-destruction testing
will be conducted on 100% of all joints. In addition, one destructive
test will be conducted for every 500 ft of joints. These destructive
tests will be accomplished in the field and confirmed in the
laboratory.
Once the closure cell design was formulated and the specifica-
tions for liner and filter fabric evolved, testing was undertaken by
the Battelle Laboratories in Columbus, Ohio, to determine the
compatibility of the materials with the possible leachate. In the
testing process, tests were conducted under the most stringent con-
ditions, utilizing actual pond sludge. The tests were done in
accordance with U.S. EPA Method 9090 and at elevated
temperatures. No deterioration of either the liner material or the
filter fabric was observed, and the lifetime expectancy of both is
in excess of 30 yr.
Once the cell has been built, the fixed material from the stockpile
will be placed in the cell, but only to a height ensuring that the
side slope gradients do not exceed 1 in 5. A cover will be placed
over the cell to encapsulate the material completely.
The cover, like the liner, has been upgraded (Figure 10). A double
liner will be placed above the material. There will be a compacted
2-ft thick clay liner, laid to the same tight specifications as the bot-
tom clay liner, followed by a 40 mil HDPE synthetic liner. Once
again, the liner will be protected by filter fabric. Above the liner,
there will be a one foot sand drainage layer followed by 18 in. of
compacted clay and top soil. The final cover will be seeded with
grass, and the whole area will be fenced.
MONITORING WELLS
Once the Closure Cell has been constructed and covered, it will
be marked and the whole area will be monitored for a minimum
of 30 yr.
To this end, 39 monitoring wells have been installed around the
WASTE STABILIZATION/FIXATION 301
-------
SCCONOANY LCACHATC COLLCCTION
ITITCM WUVCL CHAIN
to'
t O'
PRIMARY LCACHATC COLLCCTION
SYJTCM OKAVCL D«AIN
NOMIRAL «* LATCH OF
MTOHATCD ICNTOHIT;
MITC
PRIMARY LCACHATC
COLLCCTION JYJTCM
DRAIN
3§&$^^^
iiliiii^
COMFACTCO
CLAY lACItriLL
Figure R m1M».I SYHTMCTIC
Primary Leachate Collection System Details LOCKINC coven JLATC y Lmt" »HCNO«
to*
KCONOMY LCACM1TC
COU.CCTION
OI»IN K'l
JCCONMKY Lt*CM»rt
LCACIUTC COLLCCTION SYSTCM
COLLCCTION STITCH OIUVtL t"»»l—
0UVTL DHAINJPIK)
SCCONOAKY CLAY LINCM .
v&vcf&itiAWtV^:^^
.•» A *m c • / a* Am •:.'.':'.• "•:7^!^». w^l fa t*.-. ft, i •iff-ij*; < ^«i'T-'?/???T^//-\V-\vV\V!V/:-.V; •.'.•; -.V: -.VV--': •'•': '•'•': '•'••: '•'•': '•'•': '• •': '•'•': '••'.• '.••'. '•': •'. '• '.• •'. '• > •'. '•::'• ::'.:'::'r.^:'^.
COHPACTCO CLAY
Figure 9
Secondary Leachate Collection System Details
site and a further six wells will be installed. These wells will monitor
groundwater at various depths down to 165 ft. The distribution
of wells will surround all the closed ponds, and test samples taken
from these wells will be compared with samples from a number
of up-gradient wells.
CONCLUSION
When the Closure Cell is completed, it will be a state-of-the-art
landfill. Chemical Waste Management, Inc. is dedicated to devel-
oping and managing the most environmentally-sound disposal sites.
The Company has demonstrated that, working in close coopera-
tion with both the Federal and State regulatory agencies, any
potential environmental problems can be solved in an efficient and
practical manner.
REFERENCES
1. Vigon, B. W., and DeRoos, F. L., "Assessment of Waste Sludge
Stabilization Alternatives," Final Report, Battellc (Columbus)
Laboratory, July 13, 1984, and Addendum, Aug 1984.
2. Collison, G. H., "Physical Property Testing of Chemically Fixed
Material, CWMI, Vickery, Ohio," Colder Associates Report, Aug,
1984.
Figure 10
Vickery Closure Cell—Final Cover Schematic
302 WASTE STABILIZATION/FIXATION
-------
Field Experiences with Silicate-Based Systems for the
Treatment of Hazardous Wastes
G. J. Trezek
Department of Mechanical Engineering
University of California
Berkeley, California
J. Wotherspoon
Hugo Neu-Proler Co.
Terminal Island, California
D. J. Leu
California Department of Health Services
Toxic Substance Control Division
Sacramento, California
L. R. Davis
C. D. Falk
Lopat Enterprises, Inc.
Wanamassa, New Jersey
ABSTRACT
A new chemical treatment for hazardous waste applications has
been developed and found successful in an actual field application.
Soils generating leachable lead concentrations in the range of 200
to 300 mg/1 using the California WET procedure (which is far more
stringent than U.S. EPA's Extraction Procedure Toxicity test) were
subjected to treatment and subsequently re-tested for lead. Test
results show the leachable lead concentrations in the treated
material were reduced to only 2 to 4 mg/1 (the California stand-
ard is 5 mg/1). In one case, a sample having a concentration of
2,300 mg/1 was reduced to 10 mg/1 lead with only a modest in-
crease in treatment. The cost of the treatment is in the range of
$15 to $20 per ton. This chemical treatment is based on the use
of a proprietary silicate-based system in combination with a cemen-
titious fixative, such as lime, which generally does not result in
substantial volume increases, as is typical with traditional fixation
and stabilization approaches.
INTRODUCTION
Results obtained under field conditions of a new silicate-based
treatment system for mitigating leachable heavy metals are
presented. To date, chemical treatment approaches have been, for
the most part, developed in an ad hoc fashion by commercial in-
terests. Moreover, the field seems confusing because of the many
different names given to that class of techniques wherein a relatively
harmless chemical(s), usually liquid, is reacted with the hazardous
waste to render it harmless enough so that it no longer has to be
managed as a hazardous waste. For example, some speak of
chemical fixation, chemical stabilization, encapsulation or chemical
treatment. Although no standard names, definitions or tests to
reveal the effectiveness of such techniques exist, treated materials
were evaluated by the California Waste Extraction Test procedure
(WET). This test differs from the traditional U.S. EPA-Extraction
Procedure toxicity test in that treated material is ground so that
it will pass through a 10 mesh sieve and then is heated 20-40 °C
for 48 hr in citric acid instead of acetic acid for 24 hr.
The successful development and implementation of this
technology involved the collaboration nd integrated efforts of four
groups. These groups included an industry which had a problem
and elected to find a solution through treatment rather than litiga-
tion, a university that assisted in the design and evaluation of the
treatment, a state regulatory agency (Department of Health
Services) which encouraged the development of a new treatment
technology and supported the effort through a meaningful appli-
cation of the regulations, and a company (Lopat Enterprises, Inc.)
that was able to develop and produce a custom-blended chemical
system that would prove to be effective in treating widely variable
hazardous wastes.
NATURE OF THE PROBLEM
The 200 ton/day waste stream that required treatment was
generated in the process of shredding cars. This material, commonly
known as auto shredder residue, is a heterogenerous mixture of
non-ferrous residuals remaining after an automobile has been
shredded and the ferrous material removed. The size distribution
ranges from fine sand-like particles of glass, plastic, metal, etc.
to large pieces of seat cushions, dash boards, parts of tires, trim
molding, etc. Parts of electrical components can also be found
throughout the size distribution.
As a result of the shredding process, the residue also has a
30-40% moisture content. In addition, because of a high rate of
bacterial action on its organic matter, interaction of iron fines,
moisture and pressure resulting from depth of burden, large piles
of residue behave similarly to compost piles and are prone to
combustion. Once combustion occurs, the piles have been known
to smolder for long periods of time.
Based on the California WET procedure, the soluble lead content
of this waste stream is on the order of 100 to 300 mg/1. Conse-
quently, the initial attention was focused on lead because it ex-
ceeded the California hazardous waste classification threshold of
5 mg/1. The scope was expanded further to include cadmium, zinc
and PCBs. The levels of these constituents are as follows: cadmium,
0.8 to 4 mg/1; zinc, up to 2000 mg/1; and PCBs, non-detectable
to 100 mg/1.
Since the residue was considered hazardous according to the
California WET procedure, the state and local regulatory agencies
TREATMENT & DISPOSAL 303
-------
required that it be managed as a hazardous waste, thereby pre-
venting it from going to a normal municipal landfill for disposal.
The unavailability of local hazardous waste options required that
it be trucked out of state at a considerable cost. It is interesting
to note that the material satisfies the U.S. EPA requirements so
that it can be considered a nonhazardous waste in states other than
California.
TREATMENT METHODOLOGY
A successful treatment system had to satisfy the following con-
straints: (1) the treated material had to be rendered nonhazardous
according to the California WET procedure, (2) the treatment had
to be economically justifiable, and (3) because of the regulatory
burdens affiliated with becoming a treater of hazardous waste, the
material had to be rendered non-hazardous in the process line in
order to avoid evoking the hazardous waste permit regulations.
After rejecting several chemical treatment techniques such as the
direct application of caustic soda and several high pH commercial
dictating agents, a treatment system utilizing silicates was
developed. The motivation for selecting silicates is that the technical
and commercial literature indicate that they are effective in some
applications and they are relatively harmless and readily available
commercially.
A commercial silicate blend known as K-20™/Lead-in-Soil
Contaminant Control System (K-20™/LSC), developed and
manufactured by Lopat Enterprises Inc., of Wanamassa, New
Jersey, was selected because of its ability to be custom-blended
as needed for a particular application.* Typically, the
K-20™/LSC System consists of an equal mixture of a silicate
solution of varying viscosity and a "catalyst" which usually con-
tains a dispersing agent. Typically, the K-20™/LSC mixture is
prepared just prior to use from the components, i.e., part A con-
tains the silicate blends and part B contains the catalyst. The ratio
of pans A and B utilized depends on the mixture of the silicate
and the particular requirements of the field application. In this
application, a 50/50 ratio of A and B provided the greatest cost-
effectiveness and ease of use in the field.
The treatment is completed by mixing the silicate wetted residue
with a cementitious material such as lime, Pozzalime™, portland
cement, kiln dust or fly ash. To satisfy the previously mentioned
treatment goals, it was necessary to optimize the custom blend of
K-20™ with the proper amount of cementitious material so that
an effective treatment methodology could be achieved which pro-
vides the necessary mitigating characteristics to render the residue
in compliance with California standards for nonhazardous wastes.
The treated material must be allowed to cure. Residues which
are damp after treatment may require one to two days for drying
and curing. Several mechanisms have been postulated for the
efficacy of the technology. In the case of a heavy metal contamina-
tion such as lead, it is believed that a lead metasilicate is formed
which is an insoluble precipitate. The results suggest that the
K-20™/LSC silicate system deeply penetrates into the waste
material and causes tight bonding.
The development of the treatment system for the 200 ton/day
residue stream began with a series of laboratory studies in which
100 Ib samples were treated by a process of preconditioning through
screening followed by applications of various levels and blends of
K-20™/LSC and lime in order to achieve a desired level of treat-
ment and cost-effectiveness. In this case, a custom K-20™/LSC
blend was created which optimized the treatment of lead.
Basically, the custom K-20™/LSC blend plus lime resulted in
passing the California WET procedure at 5 mg/1 at a cost of $25
to $30/ton treated. However, independent studies by the Depart-
ment of Health Services indicated that treating the predominant
form of lead found in the residue (divalent form of lead oxide)
to a level of 50 mg/1 would be an acceptable standard for dispo-
sition in a municipal landfill. This decreased the treatment costs
• Lopal Industrie, Inc. ii (he owner of U.S. Palenl No. 4.47J.95I Issued Oct 9, 1984 and entitled
"ENCAPSULATING SEALANT FOR THE TREATMENT AND PRESERVATION OF
BUILDING MATERIALS" and u also the owner of a pending application on an Improved com-
position for encapsulating waste products, as described herein, and co-Invented by Dr. Charles
D. Falk and Mr. Lincoln R. Davis, employees of Lopal.
to approximately $10/ton.
The laboratory proof of the concept determination was follow-
ed by a large-scale pilot plant at the site and the full-scale installa-
tion of the system. The configuration of the treatment system in-
cluded an 8- by 20-ft screen (surplus equipment from a coal min-
ing operation), a spray chamber for the K-20™/LSC and water
mixture on the undersize material and a pug mill for mixing.
Controls were developed which aUowed equal mixtures of the
K-20™/LSC A and B solutions to be mixed on line with an
appropriate amount of water and sprayed into a hopper receiving
the screened undersized material. The screened oversize material
did not exceed the hazardous waste threshold value for lead and,
thus, did not require treatment. Approximately 50 to 60% of the
weight of the incoming material to the screen was in the fines. The
treated material was placed on a concrete pad to cure and, because
of its non-hazardous character, could be taken to a conventional
landfill for final disposal.
Unfortunately, the treatment without cementitious material does
not adequately reduce the levels of cadmium and zinc. The design
of the full-scale treatment system, however, included a provision
for lime feeding at the midpoint of the pug mill mixer. The com-
bination of K-20™/LSC with a cementitious fixative brought afl
of the metal leachate values within acceptable levels according to
the California WET procedure. For example, at a level of treat-
ment of about S20 to S25/ton residue, the metal leachate values
from the residues were reduced in the treated material, respectively,
as follows: lead, 92 to 43 mg/I; cadmium, 3.4 to 0.2 mg/1; and
zinc, 1900 to 240 mg/1.
EXPERIENCES WITH OTHER WASTES
Some preliminary work has been conducted for a national com-
pany having a major battery recycling plant in California. The first
step in the recycling process involves the milling of the batteries;
the milling essentially breaks apart the case and frees the internal
components containing lead. During the milling operation, the
plastic casings become impregnated with lead so that the waste
stream is considered a hazardous waste in California. WET lead
levels of 400 to 700 mg/1 have been measured.
Our initial results with K-20™/LSC and lime indicate that lead
levels of 40 mg/1 can be achieved at a cost of about $100/ton. Plans
are underway for field testing of the treatment through a modifi-
cation of existing equipment in the process line.
Various sludges from industrial processing that contain large
quantities of lead, on the order of 1 to 5%, are being subjected
to the treatment. In one case, a 1 to 2% heterogeneous lead sludge,
treated with custom blended K-20™/LSC and lime, yielded
results of about 140 mg/1 by the WET procedure and 0.2 mg/1
by the EP toxicity test. The approximate cost of the treatment was
approximately SlOO/ton. A large-scale field test is being considered
to further refine the process and economics of treating the 1,500,000
gal of sludge.
A K-20™/LSC System is being evaluated for a site containing
40 acres of soil contaminated with lead to a depth of about 10 ft.
This site would be a prime candidate for a mobile on-site treat-
ment system embodying this technology. Preliminary indications
are that the soil can be treated with K-20™/LSC and Poz-
zalime™, resulting in essentially a soil-like material which can be
backfilled.
The treatment also has been applied to a sludge containing
barium where the EP toxicity test levels were reduced from 400
mg/1 to 36.5 mg/1 barium at a cost of about $70/ton of sludge.
Soils containing 2000 mg/kg of arsenic and 1000 mg/kg of
chromium were treated with K-20™/LSC and lime to give a 75%
reduction in arsenic and a 90% reduction in chromium. The respec-
tive WET procedure values were 97 mg/1 and 22 mg/1. Preliminary
results on incinerator ash are also encouraging; the treatment
reduced lead levels from 17 mg/1 to 0.05 mg/1 on the EP toxicity
test at a cost of about $50/ton of ash.
CONCLUSIONS
This field-tested treatment methodology offers several unique
304 TREAf MENT & DISPOSAL
-------
advantages. Briefly, the silicate-based K-20™/LSC mixture can
be custom-blended to achieve certain desired results in terms of
treatment level for a particular waste with concurrent cost effective-
ness. In general, the volume increase of the treated material is small,
and in some cases there is no volume increase. This is particularly
important when the final disposal of residues must be considered.
It is also possible that certain treated materials could be cast into
a form which would allow their reuse as feed stock in another
manufacturing process. For example, consideration is being given
to further treating auto shredder waste residue so that it can be
used as a lightweight aggregate. Treated ash and certain sludges
are being considered as material for concrete and brick making.
Contaminated soils can be backfilled after treatment, thereby
eliminating further disposal.
Preliminary results indicate that the treatment is capable of
dealing with wastes having high concentrations of metal con-
taminents. The application of the technology is relatively straight-
forward so that it could be easily incorporated into a mobile treat-
ment system.
TREATMENT & DISPOSAL 305
-------
Lime Treatment of Liquid Waste Containing
Heavy Metals, Radionuclides and Organics
Andre DuPont
National Lime Association
Arlington, Virginia
ABSTRACT
Lime is well known for its use in softening drinking water and
the treatment of municipal wastewaters. It is becoming important
in the treatment of industrial wastewater and liquid inorganic
hazardous waste; however, there are many questions regarding
the use of lime for the treatment of liquid hazardous waste.
INTRODUCTION
Under the proposed rule on Land Disposal Restrictions 40 CFR
260 of Jan. 14, 1986, there have been many changes and revisions
for the disposal of liquid wastes. Liquid hazardous wastes, includ-
ing free liquids associated with sludge, may no longer be put in a
landfill without treatment. The current criterion for determining
the "free liquids" is to use the Paint Filter Liquid Test (Method
9095) which was promulgated on Apr. 30, 1985.
The liquid portion (free liquids) of a sludge may not contain
metals in a concentration greater than or equal to the following:
Metal
(Valence) mg/1
As( + 3) 500
As( + 5) 500
Cd(-t-2) 100
Cr( + 3) 500
Cr( + 6) 500
Hg( + 2) 20
Ni( + 2) 134
Se( + 4) 100
Se( + 6) 100
Tl( + 3) 130
The metals listed above usually are found in an acidic medium
and must undergo a treatment process before they can be dis-
posed of in a landfill. The treatment of radionuclides and organic
waste may also undergo some of the same steps outlined below:
Neutralization-
Treatment Process
—^Precipitation—
•Solidification
One method of treating liquid waste containing metals is to use
a neutralizing material. Lime often is recommended because the
calcium cation is an environmentally safe binder, since most of
the salts formed at a neutral pH are insoluble after precipitation.
Other alkalies such as sodium hydroxide form soluble salts after
precipitation at a neutral pH and may cause an environmental
problem when neutralizing an acidic metal waste.
Lime is often the chemical of choice for neutralizing acidic
metal wastes because of its effectiveness and low cost. As the pH
of an acidic metal liquid begins to increase because of lime treat-
ment, most metal cations will precipitate into a hydroxide sludge
of low solubility. Once this sludge has formed, it must undergo
further treatment to insure that the metallic sludge is completely
harmless to the environment.
On May 9, 1985. the U.S. EPA Office of Solid Waste and
Emergency Response issued a Statutory Interpretive Guidance on
the treatment of bulk hazardous waste. The agency has prohibited
the use of an absorbent material that does not chemically stabilize
or solidify a bulk hazardous waste. Examples listed as absorbents
by the U.S. EPA are vermiculite, fuller's earth, bentonite, fly ash,
fine-grained sand, shredded paper and sawdust.
The material specified for treatment is an adsorbent that
"binds the liquid waste through a chemical reaction (e.g., hydra-
tion) rather than through a physical process." The two listed
stabilization adsorbents are ponland cement and pozzolans and
lime.
When considering the cost of using an adsorbent, pozzolans
and lime are always less expensive than portland cement. Pozzo-
lanic adsorption is based on the reaction of lime and a fine-
grained siliceous material (e.g., fly ash) that combines to form a
cementious solid.
Currently some generic and patent solidification techniques are
used for the adsorption of liquid waste.'
PROCESSES
Neutralization and Precipitation
Both neutralization and precipitation are chemical processes in
which a metal cation reacts with a hydroxide anion. This is the
process of adding an hydroxide ion which then precipitates the
metals.
The process of coagulation is both a physical and chemical pro-
cess. Through the attraction of cation for anions, the suspended
solids group together to form a floe. This flocculation is accom-
plished through the process of small particles colliding together
under the mild turbulent conditions found in a stirred tank. Next,
all of the precipitated material can be removed from the stirred
tank to yield a material with a concentration of 20-50% solids.
The process of precipitation can be reversed by mixing the
sludge with a low concentration of acid at pH = 5.0. The addi-
tion of lime to an acidic metal waste creates a hydroxide sludge,
while the further addition of acid to this sludge brings down the
pH to produce an acidic metallic waste. Hence, once an acidic
metallic sludge has been treated with lime, it must undergo fur-
ther treatment to prevent the leaching of metals.
Solidification of Inorganics
To render this material harmless to the environment, it is neces-
sary to go through the process called solidification. The distinc-
tion between absorption and adsorption defines whether a sludge
306 TREATMENT & DISPOSAL
-------
is solidified. Absorption is a physical process that does not chemi-
cally stabilize a waste material; adsorption is a final chemical re-
action that forms a cementitious precipitated sludge.
As stated earlier, the U.S. EPA has prescribed the use of a poz-
zolan and lime as an effective chemical stabilizing material. The
metal sludge in the presence of free water will combine with more
lime plus the addition of fly ash to form a solid block. The lime
reacts with fine-grained siliceous material, and the metal hydrox-
ide then becomes part of the structure. This is the general process
for inorganic waste treatment. The process treatment is identical
for radionuclides.
Organic Waste Treatment
Organic wastes, however, may have a neutral pH, and the pro-
cess of neutralization and precipitation does not occur. Solidifica-
tion of organic waste occurs when the organic waste becomes part
of the lime-pozzolanic material.
TYPES OF LIME FOR
LIQUID WASTE TREATMENT
Many types of limes are available for neutralization, precipita-
tion and solidification. The two main categories of lime are quick-
lime and hydrated lime. Quicklime consists of calcium and mag-
nesium oxide from the calcination of limestone. There are three
forms of quicklime currently available in this country:
• High calcium quicklime—usually containing 90 to 95% cal-
cium oxide and 0.5 to 2.5 % magnesium oxide.
• Dolomitic quicklime—usually containing 55 to 60% calcium
oxide and 35 to 40% magnesium oxide.
• Magnesium quicklime—usually containing 85 to 90% calcium
oxide and 5 to 10% magnesium oxide.
• Commercial hydrated lime—is a dry powder obtained by treat-
ing quicklime with sufficient water to satisfy its chemical af-
finity for water, thereby converting most of the metal oxides
to metal hydroxides.
• High calcium hydrated lime—high calcium quicklime pro-
duces a hydrated lime usually containing 72 to 74% calcium
oxide and 23 to 24% water.
• Dolomitic hydrated lime (normal)—under atmospheric hydrat-
ing conditions, only the calcium oxide fraction of dolomitic
quicklime hydrates, producing a hydrated lime of the follow-
ing chemical composition: 46 to 48% calcium oxide, 33 to 34%
magnesium oxide and 15 to 17% water.
• Dolomitic hydrated lime (pressure)—this lime is produced
from dolomitic quicklime under pressure, which results in hy-
drating almost all of the magnesium oxide as well as all of the
calcium oxide, producing the following chemical composition:
40 to 42% calcium oxide, 29 to 30% magnesium oxide and 25
to 27% water.
PRECIPITATION OF METALS
Since the overall steps are clarified, the detailed process of in-
organic and organic waste treatment can be explained. The fol-
lowing shows the pH at which metal cations begin to precipitate:
Ion (Valence)
pH
Ion (Valence)
PH
Fe( + 3)
Al( + 3)
Cr( + 3)
Cu( + 2)
Fe( + 2)
Pb(+2)
2.0
4.1
5.3
5.3
5.5
6.0
Ni( + 2)
Cd( + 2)
Co( + 2)
Zn( + 2)
Mg( + 2)
Mn( + 2)
6.7
6.7
6.9
7.0
7.3
8.5
Fig. 1 shows the actual range of pH where neutralization and
precipitation occur. Notice that zinc( + 2) will completely precipi-
tate at a pH = 8.4, while cadmium will not completely precipitate
until a pH = 9.7 is reached.
11.0
10.0
LIME
NEUTRALIZATION
LIME PRECIPITATION
Figure 1
Minimum pH Value for Complete Precipitation
of Metal Ions as Hydroxides
I I I
7 * 1 10
t»
I
II
I
li ••-
Figure 2
Solubilities of Metal Hydroxides at Alkaline pH
The lowest solubility limit of a metal ion may not be reached
until the pH of the particular metal sludge is 0.5 to 1 unit above
the pH where complete precipitation occurs. A good example is
the divalent zinc ion. The zinc metal will completely precipitate
when a pH of 8.4 is reached. However, Fig. 2 shows that the
minimum solubility of the zinc cation is reached at pH = 10.
TREATMENT & DISPOSAL 307
-------
Also, if the pH of a metal sludge increases above pH = 12, the
zinc cation will become more soluble. Therefore, the conclusion
that all sludge will precipitate at the same pH is not true.
A sludge containing a combination of metals will have some
metal cations in their most insoluble stage at the precipitating pH
while other metal cations will not be as insoluble. But certainly
these metals will be precipitated and insoluble as far as a sludge
consistency is concerned. A good example is a waste sludge from
a metal canning operation. The metal sludge will contain a variety
of constituents, and the curve observed for maximum insolubility
of the metals will show a shift from that indicated in Fig. 2.
The percentage precipitations of a metallic liquid waste with a
lime treatment process are shown in Table 2 and Fig. 4 in Appen-
dix A. Appendix A contains many examples of treatment applica-
tions for the precipitation of metals.
10 0
• A
• 0
40
tS
LO
• ->
0.1
Figure 3
Relationship of pH and Radium-226 Concentration
in Phosphoric Acid "Contaminated Water" Bench Tests
PRECIPITATION OF RADIONUCLIDES
This process is similar to the treatment of heavy metals. Tradi-
tionally, highly radioactive waste has been treated with the forma-
tion of a glass binder. This typical glass binder contains lime.
Lime also precipitates radium, strontium, uranium and yttrium.
Removal of these elements is also dependent upon pH. A good
example is uranium-228. At pH = 6, only 60% can be
precipitated; at pH = 10, more than 95% of the uranium cation
can be precipitated.
Radium-226 behaves in a similar manner. Its solubility curve in
the presence of phosphoric acid is shown in Fig. 3. With lime
treatment at a pH greater than or equal to 10, the maximum
solubility of the radium ion is less than 0.25 pCi/1. Based on the
general laws of chemistry, it can be easily postulated that elements
56 through 71 and elements 88 through 103 can be precipitated
with lime at pH = 9 or above.
SOLIDIFICATION
Metals and Radlonuclldes
Metals and nonmetals can be solidified with a pozzolan and
lime after the waste has been precipitated. Metal hydroxides and
calcium salts will combine with fly ash and lime in the presence of
water to form a cementious product. A good demonstration of
this is to make a sample as shown below:
Final Solid = Lime + Fly Ash + Waste + Water
Lime = 5 to 15% by weight
Fly Ash = 50 to 65% by weight
Waste = 8 to 19% by weight
Water = 10 to 60% of original sludge by weight
Organic Waste Treatment
For an organic sludge, lime and fly ash are used to solidify the
organic waste. A good example is to make a sample. The typical
mixture ratio for the final treated solid is shown by the following
equation:
Final Solid = Lime + Fly Ash + Waste + Water
Lime = 5 to 15% by weight
Fly Ash = 50 to 65% by weight
Waste = 8 to 19% by weight
Water (for binding reaction) = 10 to 20%
APPENDIX A: EXAMPLES OF MATERIALS
THAT CAN BE TREATED WITH LIME
Metals
Lime can be used for the treatment of potable water to meet
National Interim Primary Drinking Water Contaminant Levels.
Also, lime can be used to treat a liquid hazardous waste contain-
ing metals. Under the new U.S. EPA guidelines for the disposal
of liquids containing heavy metals, lime is the material of choice
for neutralization and precipitation. The following table com-
pares the various regulatory limits for the treatment of an
aqueous medium.
Table 1
Treatment of Metals in an Aqueous Medium
Arsenic, (As -f 3, As + 5)
Barium, (B + 2)
Cadmium (Cd + 2)
Chromium, (Cr + 3)
Lead, (Pb + 2)
Mercury, (Hg + 2)
Nitrate (NO - 3)
Nickel, (Ni + 2)
Selenium (Se + 4, Se + 6)
Silver (Ag + 2)
Thalium, (Tl + 3)
Fluoride, (Fl-1)
MCU: NX'I
Interim Prim.
Drinking Water
Max. Contam-
inant Lereb
0.05
1.0
0.010
0.05
0.05
0.002
10
—
0.01
0.05
—
2.4
EPToric
Teat Max.
LeTebfor
Solid
Waste
5.0
100
1.0
5.0
5.0
0.2
—
—
1.0
5.0
—
—
Calif omta
Uslfor
Liquids In i
Hazardous
Sludge
500
—
100
500
500
20
—
134
100
—
130
—
Description of Neutralization Processes
A rsenic
The first cation on the list is arsenic; it can be found either in
308 TREATMENT & DISPOSAL
-------
the As( + 3) (arsenite) or As( + 5) (arsenate) valence state.
Aluminum sulfate (alum) or ferric sulfate coagulation at a con-
centration of 20-30 mg/1 can achieve 90% removal of As( + 5) at a
concentration of 0.3 mg/1. At a pH greater than or equal to 10.8,
lime can remove 95% of a liquid containing 0.1 10.0 mg/1 of
arsenate.
Arsenite [As( + 3)] is more difficult to coagulate. Alum (30
mg/1) can only remove 20% at a pH between 5.5 and 9.0, while
ferric sulfate (30 mg/1) removes less than 60% of 0.3 mg/1 of
arsenite.
Lime is more effective at a pH greater than or equal to 10.8 to
remove 70% of 0.3 mg/1 of arsenite.
With chlorine, arsenite can be oxidized to arsenate. However,
in highly organic water, this promotes the formation of
chloroform or tri-chlorinated methane. Hence, the use of chlorine
to oxidize arsenite to arsenate for greater removal can be a disad-
vantage to a treatment scenario.
Barium
Barium is an important metal contaminant. Alum and ferric
chloride coagulation are not effective for barium removal.
Lime softening can achieve greater than 90% removal of
Ba( + 2) in the pH range between 11 to 10 in a concentration of
7-8.5 mg/1 of Ba( +2).
Cadmium
Cadmium, a well known industrial contaminant, is found in the
+ 2 valence state. Lime softening can achieve a 78% removal of a
0.3 mg/1 of cadmium in the pH range of 8.5 to 11.3. Cadmium is
extremely soluble below pH = 7.
There is evidence that cadmium coagulation with dolomitic
lime is 99% efficient at removing cadmium. This effect was
reported by Schiller and Khalafalla in "Magnesium Case for Im-
proved Metals Removal."
Alum coagulation is reported to remove a maximum of 40%
cadmium (0.3 mg/1) at pH = 8. However, in turbid water, alum
coagulation can drop to 20% of cadmium concentration. Ferric
sulfate can remove 90% of 0.3 mg/1 of cadmium at pH = 8.
However, at pH = 7.2, cadmium removal drops to 20%.
Chromium
Chromium is found in two valence states: Cr( + 3) and Cr( + 6).
In an aqueous solution, Cr( + 3) will exist as a cation and Cr( + 6)
in an anion form as Cr2O4( - 2) and dichromate Cr2O7( - 4). The
Cr( + 6) hexavalent form is the most toxic and the most likely
pollutant in water.
Lime, alum or ferric sulfate are all capable of removing
chromium [Cr( + 3)] in excess of 90%. With a pH between 10.6
and 11.3, 98% removal of 0.15 mg/1 of Cr( + 3) can be achieved
by lime coagulation.
For Cr( + 6) removal, it is better to reduce the Cr( + 6) with fer-
ric sulfate. As ferrous iron oxidizes to ferric iron in the formation
of ferric hydroxide floe, the precipitate of chromium hydroxide is
formed. After the ferrous sulfate is added, sufficient time should
be given for the reduction of Cr( + 6) to Cr( + 3). A 99% removal
of Cr( + 6) can be achieved with pH adjustment after the reduc-
tion process.
Lead
The carbonate and hydroxide forms of lead are very insoluble.
Ferric sulfate and alum coagulation can achieve 97% removal of a
lead concentration of 0.15 mg/1. At higher lead concentrations,
alum can only achieve 80% removal, while ferric chloride can still
achieve high removal.
However, lime can remove more than 98% of a 0.15 mg/1
Pb(+2) in a pH range between 8.5 to 11.3.
Mercury
Mercury is found in two forms of its valence +2 state. The in-
organic form is known to be less toxic and will be described first.
Alum and ferric chloride can be used to coagulate Hg( + 2) (in-
organic). Ferric sulfate coagulation is best at a pH equal to 8 for
97% removal of 0.05 mg/1 of Hg( + 2) (inorganic). Alum coagula-
tion is less effective; at pH = 7, a maximum of 47% of Hg( + 2)
(inorganic) of 0.05 mg/1 can be removed.
Lime is very effective for inorganic Hg( + 2). In the pH range of
10.7 to 11.4, 60 to 80% of a 0.5 mg/1 Hg( + 2) can be removed. At
pH = 9.4, only a 30% removal can be expected.
The organic form is more commonly found and is more toxic.
Organic Hg( + 2) is much harder to remove than the inorganic
compound. In turbid water, alum and ferric sulfate can remove
up to 40% of the Hg( + 2) present. Lime is not an effective
coagulant for organic Hg( + 2) at any known pH.
Selenium
Selenium is found in two valence states, Se( + 4) (selenite) and
Se( + ) (selenate). Selenium can be found in an aqueous solution
as SeO3(-2) (selenite) or SeO4(-2) (selenate).
Ferric sulfate is most effective at pH = 5.5 for an 85% removal
of 0.03 mg/1 Se( + 4). At a higher pH, removal of selenium de-
creases. Alum coagulation is less effective with a maximum
removal of 32% of a selenite.
Lime can remove up to 35 % of a 0.03 mg/1 Se( + 4) at pH = 11.
AtalowpH = 5.5, ferric chloride is more effective for Se( + 4);
at pH greater than or equal to 11, lime is more effective.
Silver
Silver is found in the valence state Ag( + 2). Alum and ferric
sulfate coagulation is effective at a pH range between 6 and 8 for
a 70% removal of 0.15 mg/1 of Ag( + 2) in an aqueous waste.
Lime is more effective for Ag( + 2) coagulation; at pH — 11.5,
90% of 0.15 mg/1 of Ag( + 2) can be achieved.
Nickel
The most common form of nickel is (+ 2) valence state. When
lime is added to nickel, the hydroxide of nickel will precipitate
very well. At a pH between 9.5 to 10.0, the solubility of nickel
hydroxide is 0.01 mg/1.
Copper
A common valence state of copper is the (+ 2) valence state. In
the pH range between 7.0 and 11.0, the hydroxide solubility of
Cu(OH) is 0.05 mg/1.
Zinc
Lime can also do a tremendous job in removing zinc from a
waste stream. Zinc is commonly found in the ( + 2) valence state.
Zn(OH)2 in the pH range of 9 to 11 has a solubility of 1.0 mg/1.
Inorganics
Fluoride
Fluoride is not a metal; however, it is found to be a naturally
occurring contaminant in the raw water of many communities.
There is considerable controversy over the allowable limit of
fluoride [F( -1)] in drinking water. An old argument has been
that in low concentrations, fluoride is needed for the prevention
of dental decay.
The maximum fluoride level allowable in drinking water is set
at approximately 2 mg/1 at 63 °F. Fluoride normally is removed
during potable water treatment as a side reaction.
(Ca(OH)2*
-CaF2 + 2OH(-1)
(1)
TREATMENT & DISPOSAL 309
-------
Phosphate
Phosphate is an industrial pollutant that is known to cause
eutrophication of fresh-water lakes when in a high concentration.
A pH equal to 11 must be reached to reduce phosphate concentra-
tion significantly. A concentration of 300 mg/1 of Ca(OH)2 can
reduce residual phosphate to below 5.0 mg/1. Below a pH of 11,
the common resultant phosphate residue is tricalcium phosphate
Ca3(P04)2.
At a pH greater than 11, the primary compound formed is ny-
droxylapatite {CajOHfPO^]. Hydroxylapatite will form a mi-
crpfloc and may be treated with a coagulant.
Also, by using lime to achieve a pH of 11.0, the chemical oxy-
gen demand (COD) of a wastewater can be reduced from 400-600
mg/1 to a level below 200 mg/1.
Sulfiie and Sulfate
Sulfite (SOp and sulfate (SO?) are the common by-product
ions of reactions with sulfurous and sulfuric acid. These ions also
are the by-product of sulfur emissions from coal burning power
plants. Currently, there is an excess of 1.3 million tons of lime for
the treatment of these two ions. Calcium sulfite is considered to
be slightly soluble, while calcium sulfate is considered relatively
insoluble. The sulfate ion often is found in pickle liquor sludge.
Four examples are given below.
• Pickle Liquor is classified as RCRA waste K063. Treating
pickle liquor with lime results in the formation of three com-
mon calcium salts: CaSO4 1/2(H2O) Plaster of Paris; CaSO4
2(H2O) gypsum; CaSO4 anhydrite. The other compounds
are metal hydroxides such as Fe(OH)2 and Fe(OH)3. A com-
mon treatment method is to use fly ash or cement kiln dust
along with an excess of lime (3 parts lime; 1 part cement kiln
dust; 20 parts acid sludge by weight). In this treatment
scenario, the neutralization, precipitation and solidification
occur in one step.
• Cold Mining Draining—in the gold industry, the gold ore often
contains pyrite at a concentration of 9 g/ton. The pyrite con-
tent may contain between 1 and 3% sulfur. The pyrite bacteri-
ologically oxidizes to yield sulfuric acid. This oxidation pro-
cess is similar to the acid mine drainage found in the coal min-
ing industry where pyrite is also a contaminant. Lime is the
preferred material for the neutralization of this acidic waste.
• Coal Mining Drainage—coal mining operations often have
tremendous amounts of acid drainage because coal contains
K4
J=
4-1
f
1 *
i "
8
§ -
U
M id
01
d-
I
-
I
[1) Inorganic
(2) Organic
pyrite and marcasite. When a coal pile is exposed to oxygen,
the pyrite (FeSj) will oxidize to produce acid (H + ), ferrous
iron (Fe + 2) and sulfate (SO?). The ferrous iron will oxidize
to ferric iron as shown below.
2FeS2 + 702 + 2H2O +• 2Fe- 2 + 4SO? + 4H + (2)
4Fe + 2 + O2 + 4H + *• 4Fe + 3 + 2H2O (3)
Fe+3 + 3H2O B* Fe(OH)3 + 3H + (4)
Hence, hydrated lime [Ca(OH)J will undergo the following re-
action with pyritic acid mine drainage:
2Fe + 2 + 2SC# + 2Ca+ + 4OH —*>•
2Fe(OH)2 + 2CaSO4 (5)
2Fe-3 + 6(OH)- —*" 2Fe(OH)3 (6)
• Metal Recovery from Ore—Similarly, in the mining of copper
and zinc, sulfuric acid is used to leach the metal from the ore.
Lime is then used to treat the spent sulfuric acid waste.
Table 2
Metal Hydroxides: Removal of a Particular Metal in a Given pH Range
Hatal'i Br4roii4i: Vfcat i« tha raaoval of a particular
raa|a.
laparltj
laaoval
Araaaita («3)
Araa.at* (*5)
B.rl.a (.2)
Ca'.la. (»2)
Chro.l.. (.3)
Ckro.l.a («6)
Laad («2)
B|(*2) l.orf.alc
B|(*2) orgaalc
Sa (»») aalaalta*
Sa (»6) aalaaata
CoflcaatritlQa
(0.1 .|/1)
(0.1-10.0 M/D
(7-8.5 •!/!>
(0.3-10.0 a, /I)
(0.15 M/l)
Baat t« ra4.ca tri
(0.5 .|/1)
(0.5 •«/!>
(0.03 .|/1)
ll
210.8
ilO.B
lli.BilO
11.3i»Bll
11.3i,BilO
EtMclaact
701
951
901
.5 «»
.6 98X
th farroaa aalfata aad thaa
ao that a floe m»j lotm
11.3ia«2.8.5 98X
Il.tipBilO
ll«a la aot
,B - 11
.7 70X
offactl'a
aOI
Ll.a la aot affactKa
Za (.2)
Ca (»2)
HI (»2)
Cr («3)
C< (.!)
Pk (.2)
ft . 10
pB - 9.8
pB - 8.0
pB ' 11.0
pB - 11.0
0.8 .|/1
O.OS .1/1
0.01 M/l
0.01 .|/1
0.08 "I/I
0.1 M/l
•l-crric Sullilc it more cffccme >l pH « S.5 for 85* removal of 0.03 mg/1 (Se + 4)
APPENDIX B: RADIONUCLIDES
A common example of radionuclides from industry is the min-
ing of phosphate for the production of fertilizer. Radium-226 is a
common by-product associated with the mining of phosphate.
Radium-226 can be removed through the process called double
liming. The curve of precipitation versus pH for Radium-226 is
given in graph 3.
Table 3
Efficiency of Removal Percentages, Radioactive Elements
Figure 4
Metals Precipitation
Ridio»Ctl»«
Ridlui-226
Strotiua-90
Ur«nlui»-228
YtcrluB-91
pH For Bast
R««ov«l
Efflcltncj of
90X
961
951
981
310 TREATMENT & DISPOSAL
-------
Figure 5
Radioactive Elements Precipitation
APPENDIX C: ORGANIC WASTE TREATMENT
The following information is taken from a patent granted to
Conversion Systems Inc..' The following is a description of
organic sludges that can be treated with a pozzolan and lime.
1. Petroleum Sludge from Petroleum Refinery Units, pump
leakage, surface runoff, spilled lubricants and waste liquids from
housekeeping maintenance tasks (pesticide residue). This sludge
will often compromise some of the following organic fractions:
On a wet weight basis, 20% sludge can be mixed in with the
pozzolanic material.*
A. Alkanes
1. Octane (constituent of gasoline)
2. Nonanes
3. Decanes
B. Cycloalkanes
1. Cyclooctan (constituent of gasoline)
C. Alkyl benzenes
1. Ethylbenzene
2. Propylbenzene
D, Kerosene
E. Furnace Oil
F. Diesel Oil
G. Aromatics (usually C6 to C^
H. Polynuclear Aromatics
2. Acrylic Emulsion Waste from the production of acrylic resins
(e.g. acrylate) and emulsions.
On a wet weight basis, 14% sludge can be mixed in with the
pozzolanic material.*
A. Acrylic Paint Sludge
3. Watery Waste from demilitarized nerve gas and obsolete
chlorinated pesticides decommissioned by the U.S. Army. These
watery wastes contain some of the following:
On a wet weight basis, 20% sludge can be mixed in with the
pozzolanic material.*
A. Aldrin
B. Isodrin
C. Dieldrin
D. Endrin
E. Diisopropylmethylphosphonate
F. Dimethylphosphonate
G. P-Chlorophenylmethylsulfoxide
H. P-Chlorophenylmethylsulfone
4. Coking tar which is the by-product from the quenching of
volatile gas during the coking process. Coking occurs when coal
undergoes destructive distillation. Coking tar is composed of the
following various organic materials:
On a wet weight basis, 20% sludge can be mixed in with the
pozzolanic material.*
A. Benzene
B. Toluene
C. Xylenes
D. Cumenes
E. Coumarone
F. Indene Naphthalene
G. Acenophthene
H. Methylnaphthalenes
I. Fluorene
J. Phenol
K. Cresol
L. Pyridine
M. Picolines
N. Anthracene
O. Carbozole
P. Quinolines
Q. Phenanthrene
'Phosphate Extraction Process,"
REFERENCES
1. Albertson, O. and Sherwood, R.,
WPCF, Oct. 1967.
2. Chen, K. et al, "Pilot Plant Study to Treat Priority Pollutants in
Coal Pile Drainage," 45th Annual Meeting of International Water
Conference, Oct. 22, 1984.
3. Chestnut, R. et al., "Method of Stabilizing Organic Waste," U.S.
Patent # 4,514,307, Ar/ril 30, 1985; Assignee: Conversion Systems,
Inc., Horsham, PA.
4. Dean, J.G. et al., "Removing Heavy Metals from Waste Water,"
Environ. Sci. Tech. 6, 1982, 518-522.
5. "Guide to the Disposal of Chemically Stabilized and Solidified
Waste," U.S. Army Engineer Waterway Experiment Station, Vicks-
burg, MS EPA-IAG-0569, 1969.
6. U.S. EPA, "Interim Radium-226 Effluent Guidance for Phosphate
Chemicals and Phosphate Fertilizer Manufacturing, State of Con-
siderations," Aug. 5, 1974.
7. U.S. EPA, "Manual of Treatment Techniques for Meeting the In-
terim Primary Drinking Water Regulations," EPA-600/8-77-005,
1977.
8. Higgins, T.E. and Marshall, B., "Combined Treatment of Hexa-
valent Chromium with Other Heavy Metals at Alkaline pH," CH2M
Hill, Reston, VA, from the book Toxic and Hazardous Waste, Pro-
ceedings of the Seventeenth Mid-Atlantic Industrial Waste Con/.,
Technomic Publishing Co., Lancaster, PA, 1985.
*Care should be taken that the sludge containing greater than 8% by weight of any
single organic compound listed may take longer than 28 days to reach the maximum
strength developed in the pozzolanic reaction. A good example of this is the rule that
when sugar is added to pozzolans or portland cement, the reaction is retarded but the
cementious reaction does go to completion.
TREATMENT & DISPOSAL 311
-------
9. McArdle, el a/., "Treatment of Hazardous Waste Leachate," U.S.
EPA, Cincinnati, OH, 1985.
10. National Academy Press, Water Chemicals Codex. NAS, Washing-
ton, DC, 1982.
11. National Lime Association, "Chemical Lime Facts," Bulletin 214,
Fourth Ed., 1981.
12. Netzer, A., et a/., "Removal of Trace Metals from Wastewater by
Treatment with Lime and Discarded Automotive Tires," U.S. EPA,
Cincinnati, OH, EPA-600/8-77-005, 1977.
13. Skinner, J.H., "Statutory Interpretive Guidance—Treatment of
Bulk Hazardous Liquids," U.S. EPA Memorandum, May 9, 1985.
14. Spohr, G. and Tults, A., "Phosphate Removal by pH Controlled
Lime Dosage," Public Works Mag., July, 1970.
15. U.S. EPA, "Development Document for Interim Final and Pro-
posed Effluent Limitations Guidelines and New Source Perform-
ance Standards for the Ore Mining and Dressing Industry," Vol. I
& II, U.S. EPA, Washington, DC. 1975.
16. van Staden, C.M., "The Usage of Lime in the South African Gold
and Uranium Mining Industry," Rand Mines, South Africa, Inter-
national Lime Congress, Hershey, PA, 1978.
312 TREATMENT & DISPOSAL
-------
Demonstration of Land Treatment
Of Hazardous Waste
Roger L. Olsen, Ph.D.
Patricia R. Fuller
Eric J. Hinzel
Peter Smith
Camp Dresser & McKee Inc.
Denver, Colorado
ABSTRACT
Using the upper soil zone to manage wastes has been referred to
as landfarming, land spreading, land disposal, land application,
sludge farming and land treatment. The application of waste on
soil has been practiced, particularly by the petroleum industry,
for more than 30 years. On July 26, 1982, the U.S. EPA estab-
lished performance standards for the treatment of hazardous
wastes in soil under Subtitle C of RCRA. At this time, the term
"land treatment" was officially adopted. Under the performance
standards, the operator must demonstrate that the hazardous
constituents in the waste are being degraded, transformed or im-
mobilized in the soil treatment zone. Several guidance documents
have been issued by the U.S. EPA on "how to" perform the
demonstration.
Data from a land treatment facility used to dispose of hazar-
dous oily wastes from a refinery in the northwest United States
are presented. The data include concentrations of selected organic
(e.g., naphthalene and benzene) and inorganic (e.g., arsenic and
copper) compounds in the soil at depth below the treatment zone.
These data indicate that the organic chemicals in the waste are be-
ing biologically degraded, transformed and volatilized in the soil
while inorganic metals are being immobilized. Statistical analyses
on samples collected at selected depths in the soil indicate that the
hazardous constituents in the waste have not migrated below 2 to
3 ft from the surface. Furthermore, calculations indicate that typ-
ically more than 90% of the organic compounds applied are being
degraded. The unit life of the facility is limited to 20 to 30 years by
the accumulation of metals in the soil that may affect revegetation
at closure. Techniques to improve degradation including tilling,
fertilization and applications rates and methods are discussed.
Finally, applicability of land treatment for other hazardous
wastes is discussed.
INTRODUCTION
The petroleum industry has used the upper soil zone to manage
waste for more than 30 years. The incorporation of waste into the
soil will be referred to in this document as land treatment. Cur-
rently, the treatment of hazardous wastes in soil is regulated
under Subtitle C of RCRA. Some of the major performance stan-
dards contained in these regulations include:
• Control of run-on and run-off for 24-hour, 25-year storm
• Control of particulate matter by wind dispersion
• Unsaturated zone monitoring of both soil and water on a regu-
lar frequency
* Maintenance of the treatment zone no more than 5 ft below the
surface and at least 3 ft above the seasonal high water table
* Demonstration that the hazardous constituents in the waste are
being degraded, transformed or immobilized in the soil treat-
ment zone
Many of the performance standards make the use of land treat-
ment difficult. For example, in areas with a high water table such
as those encountered at refineries in the northwestern United
States, the standard of a 3-ft separation zone between the bottom
of the treatment zone and water table is not attainable due to
naturally high water tables, perched water zones or saturated, low
permeable materials near the surface. Such sites have found it
necessary to install subsurface drains or other artificial means to
lower the water table.
The necessity to demonstrate that the wastes are being degraded,
transformed or immobilized also has proven more complicated
than indicated by the performance standard. In December 1984,
the U.S. EPA issued a draft manual on how to perform the
demonstration.1 According to the Guidance Manual, the land
treatment demonstration (LTD) should consist of the following
initial evaluations:
• Reconnaissance Characterization of Waste Constituent Distri-
bution in Soil— This evaluation includes collection and analysis
of soil samples with depth in the land treatment facility and in a
background area. Four background locations and one location
per two acres of the treatment facility (minimum of six) are
recommended in the Guidance Manual. At each location, eight
samples over a depth of 20 ft are recommended. An elaborate
compositing scheme is proposed resulting in 16 samples to be
analyzed for an extensive list of parameters including the re-
duced Skinner list compounds (Tables 1 and 2). If greater than
background concentrations are found, individual samples must
be analyzed.
• Barrel Lysimeters or Field Plots—This evaluation includes
conducting barrel lysimeter or field plots studies. The barrel
lysimeters are composed of 55-gal drums that have been driven
into the ground to obtain a relatively undisturbed soil mono-
lith. The barrels are removed from the ground and waste is ap-
plied at three different rates. All tests are performed in tripli-
cate. Both the soil and effluent are collected and analyzed
with time for up to one year. In all, 12 barrel lysimeters (in-
cluding three control lysimeters) and approximately 60 samples
are recommended in the Guidance Manual.
• Toxicity Tests—This evaluation includes conducting toxicity
tests on the water soluble fraction of both the waste and waste-
soil mixtures. The proposed toxicity test uses a system to
measure the response of luminescent bacterium to the various
soluble chemicals by measuring the light output of the organ-
ism. The data are used to select maximum acceptable initial
loading rates.
Other proposed evaluations include more intensive soil/pore
water sampling, soil mapping and a 2-year follow-up study.
A new Guidance Manual has been written because of many
TREATMENT & DISPOSAL 313
-------
Table 1
Parameter* for Land Treatment Demonstration
Ganaral
Natal*
Orftnlc*
Parcant Vatar
Pareant Oil
Parcant Solid*
A*b
Solubla Salt*
Total Nltrocan
Total Phoaphorua
P«
Total Organic Carbon
13 SUnnar Llat Natal*
(*aa Tabla 2)
41 fklnnar Lilt
(••a Tabla 2)
Table 2
Appendix VIII Hazardous Constituent Sublet
for Petroleum Refinery Studies'
(Reduced Skinner List)
natal*
aatianoy
Araanic
tariw
•aryllluu
Cadalw
Chraiua
Cobalt
Laad
Marcury
Mickal
falaniua
Sllrar
Vanadin
Telatlla Organic*
••BI ana
Carboa Dlmilfida
Calorobaaian*
Chlorofora
1,2-OibroBMthaaa
1,2-Diehloroathana
1,4-Dioxaaa
Mathjrl attqrl fcatooa
Ityrant
Itbyl Baniana
TolMn*
Xylana*
Xylana*, •
Ijrlaou, o 4 t
ia»a/llautral Organic*
Anthracana
kant(a)anthracana
lanz(b)(luoranthan*
»a»«/H»iltr«l Organic* (Coat.)
»auo( J ) (loo ran tbana
•aBie(k)(luoraatbaM
•ao*o(a)nrraaa
lU(2-atn7lb*x7l)phthalat*
iutyl bauyl phthalata
CarjraaM
Dibau(a,a)aerldiiia
Dlbanx(a,h)anthracan*
Di-B-Dvrjrl pkthalata
DlchlorobaniaM*
o-DiehlorobaiuaBa
o-Dlchlorobauana
a-Dteklorobauaaa
Diathjrl ahthalata
7,12-OiMthrltMn«(>)uthracao*
Maalhyl phthalata
Pi • octyl pethalata
Pluoraa
Indaa*
Ha thy 1
1-Hatlqrbupbthalaaa
Haphthalana
fbaoaa tiiraoa
Pjrraoa
OlllDOllM
*el< Organic*
lanianathlol
Craaola
o-Cra*ol
p 4 B-Cra*ol
2,4-DlMtb7lphanol
2,4-Oiaitrophaiiol
4-«itrophanol
fbanol
adverse comments concerning the proposed LTD methods. The
new Guidance Manual is currently in review and will focus more
on actual sampling and contaminant fate modeling versus barrel
lysimeter and toxicity testing. Overall, the best methodology used
to perform an LTD may become a less important issue. On Jan.
14, 1986, the U.S. EPA proposed its Land Disposal Restrictions
which may severely limit future land treatment of RCRA hazar-
dous wastes.
In the next section, the results of the first step of an LTD, Re-
connaissance Characterization of Waste Constituent Distribution
in Soil, are discussed at one land treatment facility used to treat
petroleum refinery waste in the northwestern United States.
CHARACTERIZATION OF WASTE CONSTITUENT
DISTRIBUTION IN SOIL
The purpose of this phase of the LTD is to determine the depth
314 TREATMENT & DISPOSAL
to which hazardous constituents have moved below the zone of
waste incorporation and to document the degree to which
degradation, immobilization and/or transformation of the hazar-
dous constituents are occurring within the treatment zone.
Methodology
As recommended in the Guidance Manual, a minimum of six
locations were randomly selected on the treatment facility. In ad-
dition, two locations were selected to represent "hot" (visually
black, high quantity disposal) and "wet" (standing water) spots.
Four locations were also randomly selected in the background
area. Continuous split spoon samples were collected at each loca-
tion to a depth of 10 ft. In addition, a split spoon sample also was
collected at IS to 16.5 ft. Samples were selected for laboratory
analyses based on field observations (e.g., bottom of oily material
or change in lithology or horizon). Typically, the following
samples were collected at several depths at each location for
analyses:
• 0-12 in.
• 18-24 in.
• 30-42 in.
• 54-68 in.
• 90-102 in.
As shown, samples were composited over a depth of 6 to 12 in.
that represented the amount of material needed to fill the
laboratory bottles. Therefore, the samples actually were not com-
posites but represented the entire 12 in. interval. No extensive
compositing as proposed in the Guidance Manual was performed
because in similar cases, statistical analyses indicated that in-
dividual samples would have to be analyzed to perform the re-
quired evaluations.
The resulting sampling program resulted in 67 samples (12 loca-
tions multiplied by 5 to 6 samples per location). Because of the
large number of samples and the decision not to make com-
posites, the cost of analyzing the samples for all parameters would
be cost prohibitive (Table 1 parameters currently cost approxi-
mately $2,500 per sample). Therefore, all samples were analyzed
by the following screening techniques:
Screening Parameters
Methodology
Aromatic Compounds (e.g., benzene,
toluene, etc.)
Polyaromatic Compounds (e.g., naph-
thalene, phenamhrene, etc.)
Metals (antimony, arsenic, chromium,
copper, lead and zinc)
PH
Electrical Conductivity
Oil, water and solids
Modified Method
80201
Modified Method
8310'
6010, 7060, 7041'
12-2.6*
A.2.2.61
As shown, the screening methods used for analyses of the
organic compounds were gas chromatographic (GC) techniques
(Method 8020) and high-performance liquid chromatographic
(HPLC) techniques (Method 8310). To assure correct identifica-
tion of the organic compounds and to verify that the correct
screening parameters had been selected, 10% of the samples were
analyzed for all of the parameters shown in Table 1. Organic com-
pounds were analyzed by gas chromatographic/mass spectro-
metric (GC/MS) techniques and metals were analyzed by induc-
tively coupled plasma (ICP) emission spectroscopic or atomic ab-
sorption (AA) spectroscopic methods.
-------
Results
Organic Compounds
The GC and HPLC screening procedures were able to identify
soils containing no contamination at similar or lower detection
levels than the GC/MS method. This conclusion is illustrated by
the following detection limits typically obtained:
Compound
Units
Detection Limits
GC/MS Screen
Anthracene
Fluoranthene
Toluene
Xylene
mg/Kg
mg/Kg
/*g/Kg
Atg/Kg
0.16
0.16
5
5
0.01
0.1
3
5
Therefore, the screening techniques were able to accurately iden-
tify "clean" versus "contaminated" soils.
When highly contaminated soils were analyzed, however, the
screening methods resulted in higher values than the GC/MS
methods for the same compound. That is, the screening tech-
niques were not in all cases able to resolve various compounds into
individual components. Therefore, the reported value actually
represented several compounds. This phenomenon is often re-
ferred to as "false positives." The concentrations reported by the
screening techniques may be one to three orders of magnitude
high.
Based on the analyses of percent of oil with depth, the average
amount of oil remaining in the zone of incorporation (a depth
ranging from 5 to 24 in.) was 11 % by weight. Since 1977 when the
treatment facility was first used, 15,000 tons of waste containing
4,300 tons of oil have been applied. Based on the quantity of oil
remaining, 64% of the oil that has been applied has been degrad-
ed. Based on the analyses of the waste and the soil, the percent of
degradation of selected compounds also can be calculated. As
shown in Table 3, more than 99% of the volatile compounds have
been removed from the soil. This loss is probably the result of
both volatilization and biodegradation. The percentage degrada-
tion of the polyaromatic compounds ranged from 30 to 95%. The
low degradation percent calculated for chrysene may be due to its
extremely small concentration (near detection limits) found in the
waste. No acid extractable organic compounds (e.g., phenols and
cresols) were detected in the soil; therefore, their degradation rate
would be 100%.
Table 3
Percent Degradation of Selected Compounds
Coipound
tuiint
athylbeuene
Toluua
»»P-Xylene
•-lylint
1-Mthylnaphthalene
Kiphthalene
Fhtnanthrtm
Cfcryiene
Fjrrene
Applied
(toni)
3.81
7.43
23.29
57.07
23.74
17.30
6.84
25.42
2.13
2.14
Remaining
(tOM)
0.034
0.026
0.032
0.085
0.089
2.833
0.325
6.288
1.479
0.407
Fercent
Degradation
99.1
99.
99.
99.
99.
83.
95.
75.
30.
80.
Metals
Unlike the organic compounds, the metals in the waste applied
to the field do not degrade; rather, they accumulate. Based on the
analyses of the waste and soil samples, the quantity of metals ap-
plied to the treatment facility and remaining in the zone of incor-
poration can be calculated. As shown in Table 4, the amount of
Cr and Zn applied is almost equal to the amount remaining on the
treatment facility. If the sampling was representative and the
volume calculations were correct, the values should be equal. For
Cu, Pb and Sb, however, the calculations indicate that greater
amounts of these metals exist on the treatment field than were ap-
plied. Some possible explanations for this observation include:
• The quantity of waste applied was actually greater than
records indicate
• The calculated volume of soil containing the metals was too
large
• The concentrations measured in the waste were larger in the
past
• The concentrations measured in the soil were actually less
Even though the exact explanation is not known, it is clear that
the metals are being immobilized in the zone of incorporation.
This statement will be verified by the migration assessment
presented in the next section.
Table 4
Quantity of Metals Immobilized
M«t«l
A*
Cr
Fb
Sb
Cu
Zn
Applied Measured on Facility Background
(tons) (toni) (toni)
1.67
4.37
1.04
3.20
1.48
4.89
0.61
4.01
3.01
16.02
3.21
6.43
0.13
0.57
0.13
__ 1
0.41
0.78
Remaining2
(toni)
0.48
3.44
2.88
16.02
2.80
5.65
1 All values = Not Detected = 0.2 - 0.4 /ig/g
2 Remaining = Measured on Facility - Background
Migration Assessment
To determine if contaminants were migrating below the zone of
incorporation of the waste, the concentrations of the metal con-
taminants were statistically compared at the 95% confidence level
to the concentration measured in background soils. Statistical
analyses for the organic compounds of concern could not be per-
formed because values were not detected in the background soils.
Therefore, any soil depths in the treatment facility having a con-
centration of any organic compound above the detection limit
were assumed to have potential migration to that depth. The
results of the comparison are shown in Table 5. Depths below the
zone of incorporation of the waste (24 in.) with contamination
above background concentrations are indicated by an "X" on the
table. As shown, only two of the eight locations revealed signifi-
cant migration below 24 in.
Table 5
Observed Concentrations Above Background
D*pth Bu«/
(Inchu) Nwltr*l» Volatile! Aj Cr Cu Pb Sb Zn
16 - 30 X
M - 54 I
— non« -
— nom •
• noni —.
TREATMENT & DISPOSAL 315
-------
For location 5, the two compounds (phenanthrene and pyrenc)
found at the 26- to 30-in. depth were very near detection limits.
The concentrations observed at depth at location 1, although near
the detection limits, appear to be real and may have resulted from
the installation of a lysimeter near this location.
As shown in Table 5, none of the metals hase migrated below
the zone of incorporation, confirming the early statement that the
metals are being immobilized.
Calculation of Unit Life
The concentrations of metals increase with time in the soil
because the metals are being immobilized in the zone of incor-
poration. Therefore, the unit life of the treatment facility is
limited by the amount of metals. Current acceptable concentra-
tions at closure are shown in Table 6. As shown in this table, zinc
and copper would drastically limit the life of the treatment facility
to less than 5 years. The acceptable concentrations shown,
however, are conservatively low and typically based on phyto-
toxic levels of the metal to specific plant species.
If moderate pH values above 6.5 are maintained, the metals
such as copper and zinc typically are not available for plant up-
take. If the criteria values are increased by a factor of two, the
unit life increases to 20 to 40 years. Other possible alternatives in-
clude use of Cu- and Zn-tolerant plants, soil amendment or top-
soil addition at closure.
Table 6
Calculated Unit Life
Table 7
Summary of Optimal and Observed Soil Properties
oH.rY.41
rrep«riy
C/» MtlM
C/r 14<1>
etc
M
1C
Unit!
Ml/100 f
• .H.
«h«l/o
UVI1M1
falM
<0il-100il
500il-«00il
>10
4.0-4.0
0.0
4v«r«g«
1 00.1
XX), 1
14.4
4.4
2.0
-"
Mil-lJOil
700il-UOil
11-33
4.1-7.4
0.4-5.1
«—"*«-
A44 HltrOfW
^ ^ ^ ifc»>«Blioruj
444 HM
T«ilar«
T»«»«r«twr«
»«l«r Talll
<40> cUr
20-3 J
30-VO
fl » (MI talOTr
U1
11
rokic- D»«f plov.Df
-r»fcle
1V2I2
aaflr mm
Iro 4»rll .
2&-100 fU»ln«t curUe*
*ft*tM fro*
Afril -
1-4 UlBlBatti vaitt
•f^llcatloo in
lover portion
•urlau vttet
— « Not Determined or no action necessary
1 For Zone of Incorporation
2 Field Estimate
ta«mr
todo*
*r»Jc
l>rliai
tB7llb>
CadM,.
Orali»
CbtaOl
QW-
lad
Iknur
«dBl
9>>Kl»
tttar
tn!U>
UK
taKIj
1156
31
an1
0.3J1
1.22
273
132
U7
U>
0.12
41J
B1'5
0.3s
S71
434
Ora.cr.tta
-
3CO
^
30
3
1000
200
230
BOD
_
100
J
_
300
300
tar (lb)
IOUJ
340.*
47.4
0.12
l.t
11X1.1
4.7
J94.J
2H.4
0.41
52.4
4.0
0.40
27.1
1335.1
(bit
Ufa (jrc)
—
39.1
22,000
51.4
32.2
1497
4.3
143.4
—
51.4
4
_ .
*»
2.4
t Zone of Incorporation
2 Baud on one umple
} ND for Selenium •= 6 0 pf/g
4 Cannot be calculated because the detection limn i
greater than the acceptable concentration
Recommendations
As shown by the analyses of soil samples discussed in the
previous section, the treatment facility is functioning properly
and the hazardous constituents in the waste are being degraded,
transformed or immobilized in the treatment zone. That is, the
LTD has been completed and no further tests (e.g., barrel
lysimeters) are necessary. The nonmigration of the hazardous
constituents, however, will be verified by groundwater monitor-
ing. This will assure that no migration from the treatment zone is
occurring.
Even though the treatment facility is functioning properly, fur-
ther improvements could be made. These are summarized in
Table 7. By following the recommendations shown in this table,
degradation will be enhanced further.
APPLICATION AT OTHER
HAZARDOUS WASTE SITES
As previously stated, land treatment has been applied most
widely at petroleum refineries, but several other RCRA and
CERCLA sites also are using or proposing to use some form of
biodegradation as pan of closure.*-10 Treatment methods range
from direct land farming of waste to enhanced treatment in lined
cells. In most cases, biodegradation has been shown to be the
most cost-effective alternative with costs for treatment being be-
tween $50 and $100 per ton.
Some recent studies have shown biodegradation to be an inef-
fective technique for the treatment of the high molecular weight
polyaromatic compounds and other compounds such as penta-
chlorophenol."'12 This finding may be correct for some
chlorinated compounds (e.g., dioxin); however, biodegradation is
still a useful technique to reduce the volume of waste whether or
not all the hazardous components are destroyed. After
biodegradation is applied, some further treatment or containment
may be necessary to achieve final closure.
The current alternatives to elimination of land treatment for all
waste are limited. Some techniques such as waste recycling and
solvent extraction technologies do show some promise; however,
the resulting costs ultimately will be much higher than land treat-
ment.
REFERENCES
1. U.S. EPA, "Permit Guidance Manual on Hazardous Waste Land
Treatment Demonstration," EPA/S30-SW-84-015, 1984.
2. U.S. EPA, "Petitions to Delist Hazardous Wastes, A Guidance
Manual," EPA/530-SW-85-003, 1985.
3. U.S. EPA, "Test Methods for Evaluating Solid Waste," SW-846,
1982.
4. Page, A.L. (Ed.), Methods of Soil Analysis, American Society of
Agronomy, Inc., Madison, WI, 1982.
316 TREATMENT & DISPOSAL
-------
5. Rocky Mountain Analytical, Arvada, CO.
6. Patnode, T., Linkenheil, R. and Lynch, J.W., "Closure and Re-
medial Action at a Creosote Impoundment," Proc. National Con-
ference on Management of Uncontrolled Hazardous Waste Sites,
Washington, DC, 1985, 323-325.
7. Linkenheil, R.J., et al., "On-Site Treatment of Creosote Contam-
inated Soils," HAZTECH International, Denver, CO, 1986.
8. Ramsey, Steimle and Chaconas, "Renovation of a Wood Treating
Facility," Proc. National Conference on Management of Uncon-
trolled Hazardous Waste Sites, Washington, DC, 1981, 212-214.
9. Bogart, J., "Modern Technology," Juliet, TN, personal communi-
cation, 1986.
10. Planning, Design and Research Engineers, "Closure Plan for Sur-
face Impoundment at Langdale Forest Products Co., Sweet water,
TN, 1986.
11. Bulman, T.L., Lesage, S., Fowlie, P.J.A., and Wheeler, M.D.,
"The Persistence of Polynuclear Aromatic Hydrocarbon in Soils,"
Environmental Protection Service, Environment Canada, PACE
Report No. 85-2, 1985.
12. Rochkind, M.L., Sayler, O.S. and Blackburn, J.W., "Microbial De-
composition of Chlorinated Aromatic Compounds," U.S. EPA,
Hazardous Waste Engineering Research Laboratory, Cincinnati,
OH, 1986.
TREATMENT & DISPOSAL 317
-------
The B.E.S.T. Sludge Treatment Process:
An Innovative Alternative Used at a Superfund Site
Jose A. Burruel, P.E.
Resources Conservation Co.
Bellevue, Washington
Shane Hitchcock
Mike Norman
U.S. Environmental Protection Agency
Atlanta, Georgia
Mary Jane Lampkins
Roy F. Weston, Inc.
Decatur, Georgia
ABSTRACT
As the cost of cleaning up oily sludge impoundments increases,
there arises a need for alternatives to the traditional means of
sludge disposal. Several alternatives have been proposed and
some are being tested, but the B.E.S.T.™ (Basic Extraction
Sludge Treatment) process currently is being used to clean up a
Superfund site near Savannah, Georgia. This full-scale 100 ton/
day solvent extraction unit is being used to process approximately
10,000 tons of hazardous waste which were abandoned in 1975.
Resources Conservation Co., which owns the B.E.S.T.™
patents, is currently responsible for the cleanup of four acidic
sludge ponds, contaminated filtercake and backfill lagoon
material. The cleanup involves neutralizing the sludge from the
ponds, screening the filtercake and backfill and then blending.
The mixture then is processed through B.E.S.T.™ where it is sep-
arated into three factions: oil, water and solids. The oil is trucked
off-site and sold as bunker fuel; the water is treated on-site and
trucked to a large local wastewater treatment facility; and the
solids, having been rendered non-hazardous, are disposed of on-
site.
The B.E.S.T.™ process handles difficult-to-treat, emulsified
oily sludge by breaking the emulsion and chemically separating
the sludge into its components. These fractions (oil, water and
solids) then can be handled separately, effectively and with less
expense than using traditional means.
INTRODUCTION
Removal actions at hazardous waste sites generally have in-
volved the excavation of site contaminated solids with their
re-disposal at RCRA-approved landfills. Several recent develop-
ments have discouraged this "hole-to-hole" concept of waste site
cleanup. The 1984 reauthorization of RCRA has limited land
disposal of hazardous substances, and escalating landfill costs
have made alternative technologies more feasible. Also, current
U.S. EPA policy encouraged the use of innovative technology to
avoid potential long-term public health and environmental im-
pacts of off-site land disposal.
The U.S. EPA Region IV Superfund Emergency Response Pro-
gram is implementing one such innovative approach at a waste
site near the Georgia coast. Resources Conservation Co. (RCC),
through the Emergency Response Cleanup Services Contract, cur-
rently is operating its Basic Extraction Sludge Treatment
(B.E.S.T.™) system at an abandoned oil re-refining site.
THE B.E.S.T. PROCESS
Resources Conservation Co. (RCC) developed and patented the
B.E.S.T.™ process in the mid-1970s as a means of dewatering
municipal wastewater sludges. The process was proven to success-
fully recover solids high enough in nutrients to be sold as animal
feed or fertilizer. The low price of these products combined with
the availability of inexpensive disposal alternatives made commer-
cialization uneconomical at the time. The process was not
developed further until 1984 when environmental legislation
under RCRA escalated hazardous waste disposal costs. As a
result, investigation of B.E.S.T.™ as a method for the treatment
of oily sludges was initiated. After an intensive market study,
RCC felt that it could provide a totally engineered processing
plant at competitive prices to process listed and non-listed oily
wastes (Table 1).
Table 1
RCRA Listed Hazardous Wastes
K001 Creosote-Saturated Sludge
K048 Dissolved Air Floation (DAF) Float
K049 Slop Oil Emulsion Solids
KOSO Heat Exchanger Bundles Cleaning Sludge
KOS1 API Separator Sludge
K052 Tank Bottoms (Leaded)
Non-Listed Hazardous Wastes
• Primary oil/solids/water separation sludges
• Secondary oil/solids/water separation sludges
• Bio-sludges
• Cooling Tower sludges
• HF Alkglation sludges
• Waste FCC Catalyst
• Spent Catalyst
• Stretford Unit Solution
• Tank Bottoms
• Treated Clays
318 TREATMENT & DISPOSAL
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Figure 1
B.E.S.T. Sludge Processing Unit on Location
In 1985 RCC built its first full-scale unit. This unit has a
nominal capacity of 100 tons/day (wet throughput) and can
handle sludges which contain up to 30% oil and up to 40% solids,
without modifications (Fig. 1). Actual throughput, however, will
vary with the actual composition and chemistry of the sludge.
B.E.S.T.™ was designed using modular concepts which makes
the unit mobile. The ability to move the unit from site to site
enables RCC to contract B.E.S.T.™ on a fee basis. By owning
and operating B.E.S.T.™ units, RCC can contract cleanup work
and free customers from capital expenditures.
The key to the patented B.E.S.T.™ process is the use of one or
more of a family of aliphatic amine solvents to effectively break
oil-water emulsions and thus release bonded water in the sludge.
The aliphatic amines have a unique property: cooled below 20 °C
they become completely miscible with water, but upon heating
they become immiscible (Fig. 2). To take advantage of this
"solubility" property, the B.E.S.T.™ process mixes the
refrigerated amine solvent with the oily sludges. The solvent im-
mediately liquifies the sludge and turns the mixture into a
homogenous solution. Since the temperature is kept below the
solubility line, solids are no longer bonded by the oil/water emul-
sion that was part of the original sludge and are released from the
solution. Once the solids are removed, the temperature of the liq-
uid fraction, which contains the oil, water and solvent, is heated
above the solubility point and the water separates from the oil and
solvent. The last step in the process is to remove the solvent from
the oil using classical distillation.
80 -
70 -
60 -
LJ
a:
LJ
OL
50 -
40 -
30 -
20 -
10 -
• SOLVENT-WATER
IMMISCIBLE*
• WATER-SOLVENT-OIL
MISCIBLE
, —
0
WATER
1
0.2
1
0.4
1
0.6
1
0.8
1
1.0
AMINE
* OIL STAYS WTH SOLVENT DURING SEPARATION
Figure 2
Aliphatic Amine-Water Solubility
In Fig. 3, the B.E.S.T.™ process flow is diagrammed. The
sludge is introduced to the solvent in a mix tank. The refrigerated
solvent is agitated along with the sludge. This step constitutes the
first stage of the extraction process. The mixture then is sent to a
solid bowl decanter centrifuge where it is separated under the
force of several thousands g's. A centrifuge is used to increase the
rate of the solids separation and to insure that sub-micron-size
particles are'removed. It is critical to a successful operation that
the first centrifuge obtain a very high capture rate and produce
very clear centrate because any carryover of solids may result in
the formation of "rag" layers in the decanter or emulsions in the
oil product resulting in degraded oil. The solid cake from the first
centrifuge normally contains approximately 50% solids by
weight. These solids are sent to a second mixing tank and the
solids are again washed with the solvent. By this time, the oil has
been extracted from the solids twice and has been reduced to
about 1% by weight.
The solids can be washed further by pressing them through a
multiple stage countercurrent extractor which can reduce the oil
concentration in the solids to less than 0.01%. If very low oil
levels are not required, the countercurrent extractor may be by-
passed. At this point, the solids are essentially free of oil and
water and are sent to a second centrifuge where they are concen-
trated to about 50% by weight. This cake is sent to a dryer which
is a hollow disc indirect heater that uses steam as the heating
medium. Since the solvent has a lower heat of vaporization than
water, the drying step requires less energy than if water were being
TREATMENT & DISPOSAL 319
-------
evaporated.
The centrate that leaves the first centrifuge is essentially free of
solids and contains all the oil and water extracted from the raw
sludge. This centrate, which is still cool and, therefore, in solution
with the amine solvent, is heated in a series of heat exchangers to
a temperature well above the solubility curve; thus, the mixture is
in the immiscible region. This two-phase stream is passed through
a decanter where the lower water fraction is separated and sent to
a stripping column to remove residual solvent. The top fraction
leaving the decanter is primarily the solvent containing oil ex-
tracted from the raw sludge. This top oil/solvent fraction is sent
to a second stripping column where the solvent is recovered and
the oil is discharged.
The overheads are stripped off as an azeotrope containing 10<%
water and 90% solvent by weight. These overheads are sent, along
with the solvent vapors from the dryer, to a condenser from
which the condensate is sent to a second decanter. In the
decanter, the bottom water fraction is removed and recycled
through the water stripper; what is left is pure recovered solvent.
The recovered solvent is refrigerated and returned to the begin-
ning of the process, and the cycle is repeated.
SITE HISTORY
The General Refining site located near Savannah, Georgia, was
operated as a waste oil re-refining facility from the early 1950s un-
til 1975. The sulfuric acid used to treat the oil produced an acidic
oily sludge and oily filter cake as by-products. The sludge was
disposed of in four unlined lagoons, and the filter cake was buried
and stockpiled on-site.
An additional unlined lagoon that had been used as an oil-
water separator subsequently was backfilled with filter cake and
sludge. There was also waste oil stored in bulk tanks on-site. The
total volume of waste has been estimated to be in excess of 10,000
tons.
Analysis of waste oil, sludge and filter cake revealed the
presence of petroleum compounds and heavy metals including
lead (16-10,000 ppm) and copper (83-190 ppm). PCBs were de-
tected in all samples at low concentrations ( < 10 ppm). The
lagoon sludge and associated water have a pH of less than 2.
Lead, copper, PCBs, oil and grease detected in the groundwater
beneath the site threaten nearby drinking water supplies.
To remedy the situation, site cleanup actions were initiated to
stabilize the site, secure the facility and explore disposal alter-
natives. In evaluating disposal alternatives, consideration was
given to both on-site and off-site incineration, land filling and an
on-site solvent extraction process. The various methods were
evaluated primarily on the basis of cleanup time and cost. With
the exception of landfilling, all options offered an ultimate solu-
tion to the waste disposal problem at the site.
Because the B.E.S.T.™ solvent extraction process required
neither major transportation costs (as in the case of off-site in-
cineration) nor an involved testing and permitting process (as in
the case of on-site incineration), it was chosen as the most suitable
and cost-effective disposal option for this site.
A three-phase approach was implemented to identify any site-
specific problems that may have resulted in the system being in-
compatible with the wastes at the site. Phase I included detailed
analyses of all waste streams and pond strata to identify treatment
and disposal requirements. Pilot-scale testing was conducted dur-
ing Phase II to evaluate each component to determine treatment
system operating requirements. Phase III, which currently is
underway, includes the mobilization and on-site operation of the
mobile treatment system.
PROCESS OVERVIEW
Processing the hazardous waste at the General Refining site
starts with front end materials handling (Fig. 4). As previously
discussed, the filter cake and backfill material are screened in-
dependently from the sludge and placed in piles. The sludge is
pumped out of the ponds and placed into large holding tanks.
When the sludge storage tank inventory is reduced, the neutraliza-
tion step begins.
Neutralization is accomplished by mechanically mixing the
wastes with sodium hydroxide. The raw sludge is blended with the
filter cake and backfilled lagoon solids until the mixture is
homogenous and the pH is appropriate. This mixture, which is
approximately ~10% water, 10% oil and 20% solids, is pumped to
the sludge storage tank where it is pumped to the B.E.S.T.™ and
processed.
Since the ponds are stratified, free water from the ponds is
pumped out separately into a holding tank which stores water to
be processed by B.E.S.T.™ along with the sludge. Depending on
the operating needs of B.E.S.T.™, part or all of the free water
can be pumped directly to Water Treatment, bypassing B.E.S.T.™
altogether.
The Water Treatment plant is a modular facility using two-
stage clarification. The first stage consists of acidifying the water
and adding a flocculant and an oil/water emulsion breaker. Solids
removal is accomplished in a contact clarifier. Lime is added to
increase the pH, and alum is added to precipitate the heavy metals
(in particular lead). Again, a contact clarifier is used to settle out
KXJ08 PRODUCT
Figure 3
B.E.S.T. Process Flow Diagram
Figure 4
Process Overview
320 TREATMENT & DISPOSAL
-------
ludge materials. A centrifuge is used to dewater the clarifier
underflows, and the rejected water treatment sludge is returned to
B.E.S.T.™ for retreatment.
Since the General Refining site is an inactive site, RCC was re-
quired to supply all required utilities except electricity and service
water. RCC provided a mobile oil-fired boiler and a cooling tower
instrument air module which provides the necessary steam, cooling
water and instrumentation air for process equipment operation.
OPERATIONAL EXPERIENCE
The B.E.S.T:™ unit installation was completed in July 1986 at
which time waste material was first introduced into the system.
Although some mechanical problems have been encountered since
system startup, the B.E.S.T.™ unit has consistently separated the
sludge into fractions that meet or exceed contractual require-
ments.
The front end materials handling operation necessitated the use
of several types of solids processing equipment. Since all site
material was required to be less than 1/4 in. mesh, the solids pile
of filter cake and backfill had to be screened. Difficulties were en-
countered meeting the 1/4 in. screening requirement. Original ef-
forts were made to pass filter cake material through a 1/4 in.
vibrating dry screen; however, the high moisture and oil content
in the filter cake material adversely affected the efficiency of this
operation by allowing formation of conglomerate material which
would not pass through the screen.
A change was made from the vibrating dry screen to a 1/4 in.
hammer mill, which crushes material to a desired size. However, a
2 in. drag screen was required in conjunction with the hammer-
mill to pre-screen metal and other objects that could damage the
unit. This drag screen limits the rate of filter cake processing and
may back up materials handling operations.
Screening of the sludge from the ponds, in contrast to the filter
cake solids, has been successfully accomplished using a vibrating
screen. The sludge is pumped from the ponds using a submerged
double diaphragm pump into the vibrating screen where it is mixed
with sodium hydroxide. The screened sludge and caustic drop into
a mixing tank where they are mixed with the filter cake solids.
This mixture is pumped into a storage tank to await treatment in
B.E.S.T.™. The consistent reliability of this equipment to handle
this very difficult material (viscosities in excess of 1,000,000 cen-
tipoises) has been one of the successes at the site.
Unfortunately, the B.E.S.T.™ unit itself has not been free of
mechanical difficulties. Three problem areas have been the centri-
fuge seals, the dryer solids conveying system and the control of
the solvent stripper.
Triethylamine, the solvent which is used at the General Refin-
ing site, can be flammable in the presence of air. Therefore, all
unit processes must be sealed from the atmosphere and kept
under a nitrogen blanket. Since centrifuges are not inherently leak
tight, special close tolerance seals were designed by the manufac-
turer. These seals were purged with nitrogen. Unfortunately, the
seals never worked and when they failed they caused the bearings
to fail. After many centrifuge outages, a suitable material for the
seals was discovered, although some triethylamine continued to
leak. A search for an appropriate seal design continues, although
the centrifuges are now operational.
The successful conveyance of dried solids out of the dryer re-
quires one to maintain a constant solids level at the solids exit
chute and control the pressure in the dryer. The first design failed
to achieve either requirement. As a result, the solids could not be
removed from the unit without leaking triethylamine vapors ac-
companied by large amounts of hazardous dust. Two changes are
being made to the dryer to alleviate the situation. A larger chute is
being built with a level control to control the speed of the con-
veyor. In addition, the dryer will be uncoupled from the main
condenser, making the dryer an independent unit process with its
own condenser and pressure control. It is anticipated that these
modifications will result in a controlled exit of solids from the
dryer.
The solvent still controls originally were designed to control the
energy balance of the stripping column with indirect steam heat to
the reboiler which continuously heats the oil that is being cir-
culated at the bottom of the column. Since the design is based on
stripping triethylamine as an azeotrope, live steam was used to
control the water balance in the column. Control of the live steam
proved to be difficult. As a result, the live steam control was
changed from a temperature-based control system to a propor-
tional control system. RCC also is considering the use of a direct
water injection design instead of the live steam design.
CONCLUSIONS
Land disposal is becoming a less viable answer to hazardous
waste management. Consequently, the U.S. EPA is directing ef-
forts toward innovative and alternate technology as exemplified
by Resources Conservation Co.YB.E.S.T.™ Solvent Extraction
Process. This approach is necessary to develop more environ-
mentally acceptable solutions to the hazardous waste problem.
Although the Superfund Removal Program is oriented toward
direct, effective results, it must be flexible enough to accommo-
date changing technology. In fact, due to its efficient approach,
the Removal Program is better able to evaluate new technology in
a cost-effective manner.
Although the cleanup at the General Refining site is still in its
startup stages, the B.E.S.T.™ Solvent Extraction Process's abili-
ty to make the basic sludge separation as required indicates that
B.E.S.T.™ does indeed represent a new technology and a real
viable alternative.
DISCLAIMER
The authors are solely responsible for the views and opinions
contained herein. The paper is neither an official statement by the
U.S. EPA nor is it an endorsement of the views and opinions ex-
pressed or implied on the part of the authors.
Resources Conservation Co. is a subcontractor to Haztech, Inc., for
all work at the General Refining site. Haztech, Inc. is responsible for
the materials handling portion of the contract. RCC appreciates the
assistance Haztech has provided on this project.
TREATMENT & DISPOSAL 321
-------
In Situ Air Stripping: A New Technique for Removing
Volatile Organic Contaminants from Soils
George Anastos, Ph.D., P.E.
Michael H. Corbin, P.E.
Michael F. Coia
Roy F. Weston, Inc.
West Chester, Pennsylvania
ABSTRACT
The contamination of soils and groundwater by past waste sol-
vent handling and disposal practices has been identified as one
of the major environmental concerns throughout the nation.
Numerous industrial locations and abandoned hazardous waste
sites on the National Priorities List are plagued with solvent-re-
lated contamination problems resulting from chlorinated volatile
organics in the soil and groundwater. Due to the mobility and
volatility of most chlorinated volatile organics, control of the con-
taminant source area is difficult and long-term impacts on
groundwater quality are prevalent. The U.S. EPA and state en-
vironmental agencies have not established soil cleanup standards
for volatile organics such as trichloroethylene, but recommended
water quality criteria and primary drinking water standards have
been used as a guide for hazardous waste remedial actions.
INTRODUCTION
While groundwater treatment is widely understood and prac-
ticed as a cleanup strategy, soil decontamination and treatment
techniques still are regarded as innovative technologies. The pri-
mary accepted practices for treating volatile organic contam-
inated soils have involved either site isolation through capping
or excavation with ultimate disposal in an appropriate landfill
facility. In the future, however, land disposal of solvent-con-
taminated soils will become much more difficult or even impos-
sible as the new RCRA amendments for secure land disposal be-
come operative.
This paper describes a pilot-scale, field demonstration of an
innovative technique for soil decontamination; that technique is
in situ air stripping of chlorinated volatile organics from con-
taminated soils. WESTON conducted the pilot demonstration
during a 14-week field program at a site comprised of sandy
glacial soils where open burning of waste solvents had been per-
formed periodically during a 30-yr period. Trichloroethylene
(TCE) was utilized as the indicator monitoring compound to eval-
uate the overall effectiveness of the technology.
TCE had been found in the groundwater at the site at concen-
trations two to three orders of magnitude greater than the
recommended drinking water quality criterion of 2.7 /ig/1 while
soil concentrations had been found to be as high as 5,000 mg/
kg. Due to the extensive soil contamination, an in-place soil treat-
ment option (air stripping) was recommended as a potential
source control remedial action for the site.
In situ air stripping required a pilot demonstration project be-
fore implementation as a full-scale remedial cleanup strategy. The
pilot project was designed to demonstrate the feasibility of the
technology and to develop design data for full-scale site remed-
iation.
PROCESS DESCRIPTION
In situ air stripping involves the removal of volatile organics
from a soil matrix by mechanically drawing or venting air through
the unsaiurated soil layer. The soils are gradually treated as the
volatile organics are stripped from the soil particles; volatile
compounds and soil moisture are driven into the air phase within
the soil pore spaces. The in situ air stripping system must be de-
signed and operated in accordance with the site-specific subsur-
face conditions to maximize the contaminant removal effective-
ness.
While air stripping techniques have been applied on a limited
basis for the removal of some chlorinated organics and light
molecular weight hydrocarbons from contaminated soils, overall
system effectiveness and design and operating parameters have
not been previously established. During this pilot demonstra-
tion, we investigated the relationship between TCE concentra-
tions in the soils and the air as well as the proper design values
for the air stripping parameters of air flow rate and spacing of the
extraction pipe vents. We also determined that the cost of full-
scale remediation utilizing the technology is low in comparison to
conventional remediation technologies (i.e., $15 to $20/yd3 of soil
to be treated).
SYSTEM DESIGN AND OPERATION
FOR AIR STRIPPING IN SOIL
The experimental apparatus for the in situ air stripping pilot
demonstration was comprised of a pipe vent and forced air venti-
lation system installed in the unsaturated zone along with the
necessary control mechanisms to monitor and sample the air strip-
ping process (Fig. 1).
The pilot demonstration project utilized a gas chromatograph
equipped with a photoionization detector (GC/PID) for on-line
analysis of TCE in the exhaust gases.
The system shown in Fig. 1 is described below:
• Pipe Vents—perforated PVC pipes were installed vertically into
the subsurface soils within the zones of contamination.
• Air Blowers—a closed forced-ventilation system consisting of
lateral pipe manifolds connecting the pipe vents with air blow-
ers was constructed. A separate manifold and air blower appa-
ratus was used for the extraction and injection systems.
• Air Flow Control and Measurement—ear flow measurement
annubar meters were installed to monitor air flow rates on a
continuous basis, and manifold valve arrangements were in-
stalled to control the air flow rate for the system.
• Exhaust Emissions Control—air emissions from the extraction
manifold were passed through a vapor phase activated carbon
unit prior to final discharge to the atmosphere.
322 IN Situ TREATMENT
-------
» Electric Space Heaters—an electric space heating and thermo-
stat control system was used in the small building housing the
air blowers and instrumentation to supply a relatively uniform
temperature of injection air.
• Automated Data Logging—an automated microprocessor data
logging system was used to facilitate continuous monitoring of
air flow rates, air flow pressures and temperatures.
Previous soil sampling and analysis performed at the site iden-
tified the likely presence of at least two TCE-contaminated areas
resulting from past solvent burning activities. Two separate air
stripping systems were installed at a depth of 20 ft at two contam-
inated areas. Each system used separate injection and extraction
pipe vents, manifold pipes, air blowers and sampling and moni-
toring equipment.
Electric Mr Flow Heater
Forced Drift Inaction Fin
Injection Air Bypaia Valve
InlecttonMrGampUnoPort
Injection Air Ftow Ualer
Extraction Uanlfotd
inlectlon ManHoW
1 Slotted Vertical Extractor! Vent Pipe (typ)
t SiotUd Vertical ln)*ctlonV*n1 Pip* (lyp)
0 EHlracUoniAIf Sampling Port
1 Extraction Air Flow Malar
1 Extraction AkBypaaa Valve
1 Induced Draft Exlraetton Fan
4 Vapor Carbon Package Treatment UnH
Figure 1
Schematic of Pilot Study Apparatus for In Situ Air Stripping of
Organics from the Sun
Pilot System No. 1 was designed to test air stripping of low-
level TCE contamination identified in the soil of the smaller burn
area (TCE soil concentrations of 5-50 mg/kg). Pilot System
No, 2 was designed to investigate the air stripping technology
within the more highly contaminated second burn area (TCE soil
concentration of 50-5,000 mg/kg). Table 1 shows the basic de-
sign approach of the two pilot air stripping systems.
AVAILABLE DESIGN DATA
The design and operation of an in situ air stripping system is
based upon the theory of gas movement in porous media. Air
stripping applications at hazardous waste sites must address the
chemical characteristics of contaminant migration as well as the
characteristics of air flow and pressure in the subsurface soils.
In situ air stripping, as a new technology, has received limited
attention as a potential remedial action alternative, and previous
investigations have established no design or operating parameters.
Table 1
Design Basis for the Two Pilot-Scale In Situ Air Stripping Systems
Pilot System No. 1
Pilot System No. 2
Designed for lower concentrations
of residual TCE contamination in
soil (5 to 50 mg/kg TCE)
Constant air flow rate system;
approximately 50 ftVmin
20-ft spacing for extraction pipe
vents
Designed for higher TCE con-
tamination in soil (50 to 5,000
mg/kg TCE)
Variable air flow rate system;
50to225fWmin
50-ft spacing for extraction pipe
vents
TEST PROGRAM
Data were generated during the project to establish TCE re-
moval rates, air blower pressure and flow rate characteristics,
and subsurface pressure and distance relationships. The follow-
ing general project tasks were performed to evaluate the effec-
tiveness of in situ air stripping to TCE from soil.
Soil Sampling Program
The subsurface soils at each pipe vent location were sampled
through auger/split spoon samplers to determine both TCE con-
centrations and soil characteristics. The soil from each system was
sampled before and after the air stripping investigations to pro-
vide an order of magnitude estimate of TCE removals.
Exhaust Air TCE Sampling
The exhaust air from each system was analyzed for TCE using
the on-site GC/PID. An automated switching and air purging
arrangement was developed to retrieve hourly samples from each
system. TCE concentration detection limits of 50 ppb were ob-
tained, and exhaust air TCE concentrations as high as 350 ppm
were measured during the project. The TCE air stripping trends
were established, and mass removal rates were calculated.
Evaluation of Operating Relationships
The subsurface air flow dynamics and the radius of influence
for pipe vent extraction systems were investigated. The vacuum
maintained in the soil at various flow rates and radial distances
was measured, and pressure drop relationships were developed to
recommend air blower capacities and pipe vent spacings.
AIR STRIPPING RESULTS
Both in situ air stripping pilot systems were effective in con-
sistently removing TCE and other volatile organics from the con-
taminated soils under investigation (Table 2).
In addition to analytical data relating to removal performance,
design data were obtained. These data address the relationship
between air pressure in the soil, air flow rate and vacuum pres-
sure (head) at the blowers. This work can be used to design an
in situ stripping system for other types of sites and site conditions.
Table 2
Comparison of TCE Air Stripping Results for the Two Sites
Pilot System No. 1 Results
Pilot No. 2 Results
Daily exhaust air TCE concen-
trations exhibited generally de-
creasing trends from a high
range of 5-12 ppm early in the
projects to the low range of 500-
800 ppb at the end, over a
three-month period.
TCE mass removal trends re-
sembled an increasing exponen-
tial relationship with a cumula-
tive TCE removal of about 2.2
Ib from the residual soil con-
tamination.
TCE removals of below 100 ppb
in the exhaust air may have been
achieved through continued
system operation.
Daily exhaust air TCE concentrations
remained essentially in the same range
of 250-350 ppm during the project
over a three-month period.
TCE mass removal rates resembled a
linear increasing relationship as 22-
33 Ib of TCE were removed each day
during the project. Nearly 1600 Ib of
TCE were removed from the highly
contaminated soils.
Similar TCE removal trends would
have more than likely continued under
further air stripping until TCE masses
in the soil were significantly reduced.
Only an estimated 10-20% of the TCE
was removed from the soil during the
short-term pilot test.
IN SITU TREATMENT 323
-------
DISCUSSION
The pilot-scale air stripping program demonstrated the poten-
tial application of this technology as an in situ soil treatment
strategy for remedial action cleanup of organically contaminated
soil. The project demonstrated that volatile organics (i.e., tri-
chloroethylene, 1,1,1-trichloroethane, dichloroethylene and
toluene) can be effectively removed through the use of forced air
ventilation systems such as the air stripping apparatus used in the
investigations.
In situ air stripping may have application where volatile organ-
ic contaminants are of primary concern from a remedial action
standpoint. However, each site will require separate design and
optimization consideration. Using a site-specific optimization
program, the relationships between air flow rates, soil vacuum
conditions and air stripping system layout can be determined.
The U.S. EPA is presently evaluating the use of the technology
at NPL sites to accelerate, in a cost-effective manner, the removal
of volatile organics from soil. In addition, the application of the
technology is being proposed as a means of minimizing potential
off-site exposure to volatile organics to critical receptors prior to
final remediation of contamination in the saturated zones.
We have utilized the technology for remediation at two sites in-
volving propane and chlorinated solvents, respectively. In addi-
tion, several projects are in the planning stages to develop site-
specific design information at two sites contaminated with vola-
tile organic solvents.
324 IN SITU TREATMENT
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In Situ Vitrification — A Candidate Process
For In Situ Destruction of Hazardous Waste
V.F. FitzPatrick
Pacific Northwest Laboratory
Richland, Washington
INTRODUCTION
As management of hazardous materials gains increased atten-
tion in the United States, new, more effective technologies are be-
ing sought to immobilize and/or destroy the wastes either in situ
for previously disposed wastes or at the waste generation site for
newly generated wastes. The new RCRA and CERCLA legisla-
tion, combined with proposed rule-making by the U.S. EPA, is
making landfill disposal very costly and is moving in a direction
that will severely limit future land disposal. Further, the extended
liability associated with future environmental impairment pro-
vides a significant corporate incentive to dispose and delist wastes
within the plant or waste site boundary.
Pacific Northwest Laboratory (PNL) is developing a remedial
action process for contaminated soils that is potentially signifi-
cant in its application to these concerns. Although the process was
initially developed to provide enhanced isolation to previously
disposed radioactive wastes, recent tests have shown that many
hazardous chemical wastes are also destroyed or immobilized as a
result of the treatment. The process, in situ vitrification, was
originally developed for the Department of Energy for radioactive
waste material and more recently has been adapted for selected
commercial clients for hazardous wastes.
In situ vitrification (ISV) is a thermal treatment process that
converts contaminated soil into a chemically inert and stable glass
and crystalline product. Fig. 1 illustrates how the process
operates.
A square array of four electrodes is inserted into the ground to
the desired treatment depth. Because the soil is not electrically
conductive once the moisture has been driven off, a conductive
mixture of flaked graphite and glass frit is placed among the elec-
trodes to act as the starter path. An electrical potential is applied
to the electrodes, which establishes an electrical current in the
starter path. The resultant power heats the starter path and sur-
rounding soil up to 2000 °C, well above the initial melting
temperature or fusion temperature of soils. The normal fusion
temperature of soil ranges between 110 and 1400 °C.
The graphite starter path eventually is consumed by oxidation,
and the current is transferred to the molten soil, which is now
electrically conductive. As the vitrified zone grows, it incor-
porates nonvolatile elements and destroys organic components by
pyrolysis. The pyrolyzed byproducts migrate to the surface of the
vitrified zone, where they combust in the presence of oxygen. A
hood placed over the processing area provides confinement for
the combustion gases, and the gases are drawn into the off-gas
treatment system.
PNL began developing ISV technology in late 1980 under the
support of the U.S. Department of Energy. Since then, numerous
experimental tests with varying conditions and waste types have
been conducted.2-3'7 Table 1 describes the different scales of test
units that PNL used in developing the technology. The successful
results of the 43 bench-, engineering- and pilot-scale tests have
proven the feasibility of the process. Also, economic studies have
indicated that tremendous economies of scale are attainable with
the ISV process.1 This led to the commitment to design, fabricate
and test a large-scale prototype unit. Its successful testing has
demonstrated the field utility of the large-scale unit and has pro-
ven the initial economic projections.
Table 1
ISV Test System Characteristics
System Power
Scale (kW)
Bench 30
Engineering 30
Pilot 500
Large 3,750
Electrode
Spacing (m)
0.11
0.23 - 0.36
1.2
3.5 -5.5
Vitrified Mass
per Setting
1-2 kg
0.05 - l.Ot
10 - 50 t
400- 800 t
No. of
Tests
4
25
14
4
Figure 1
The In Situ Vitrification Process
This report describes the large-scale ISV system, discusses its
capabilities and summarizes the results of testing to date. PNL
recognizes that ISV is not the solution to all hazardous waste
management problems. But judiciously applied, ISV can offer
technical and economic improvements to state-of-the-art remedial
action technology. With understanding of the process design and
functions, the waste manager can make sound judgments about
the applicability of ISV to site-specific disposal problems.
PROCESS AND OPERATION DESCRIPTION
As already described, the melt grows downward and outward
while power is maintained at sufficient levels to overcome the heat
losses from the surface and to the surrounding soil. Generally, the
melt grows outward to about 50% of the spacing of the elec-
trodes. Therefore, if the electrode spacing is 5.5 m, a melt width
of about 8.5m would be observed under nominal conditions. The
molten zone is roughly a square with slightly rounded corners, a
IN SITU TREATMENT 325
-------
shape that reflects the higher power density around the electrodes.
As the melt grows in size, the resistance of the melt decreases,
making it necessary to periodically adjust the ratio between the
voltage and the current to maintain operation at constant power.
This is done by adjusting the tap position on the primary power
supply to the electrodes. There are 14 effective taps that permit
adjusting the voltage from a maximum of 4000 V to a minimum
of 400 V per phase and the current from a minimum of 400 A to a
maximum of 4000 A per phase. Operations follow the power
equation P = 12 x R, where P is power, I is current and R is
resistance.
The large-scale process equipment for in situ vitrification is
depicted in Fig. 2. The process immobilizes contaminated soil and
isolates it from the surrounding environment. Controlled elec-
trical power is distributed to the electrodes, and special equipment
contains and treats the gaseous effluents. The process equipment
required to perform these functions is divided into five major sub-
systems:
Electrical power supply
Off-gas hood
Off-gas treatment
Off-gas support
Process control
Except for the off-gas hood, all components are contained in
three transportable trailers (Fig. 3): (1) an off-gas trailer, (2) pro-
cess control trailer and (3) support trailer. All three trailers are
mounted on wheels sufficient for a move to any site over a com-
pacted ground surface. The off-gas hood and off-gas line, which
are installed on the site for collection of the gaseous effluents, are
dismantled and placed on a flatbed trailer for transport between
the sites to be treated. The effluents exhausted from the hood are
cooled and treated in the off-gas treatment system. The entire
process is monitored and controlled from the process control
trailer.
The off-gas trailer is the most complex and expensive of the
three trailers. The off-gas treatment system cools, scrubs and
filters the gaseous effluents exhausted from the hood. The
primary components include: a gas cooler, two wet scrubber
systems (tandem nozzle scrubbers and quenchers), two heat ex-
changers, two process scrub tanks, two scrub solution pumps, a
condenser, three mist eliminators (vane separators), a heater, a
charcoal filter assembly and a blower system.
TO ELECTRODE*
AW COOLER*
I
Figure 2
Large-Scale In Situ Vitrification System
A major element of the off-gas support system is the glycol
cooling system, which is mounted on the support trailer. This
system interfaces with the scrub solution and extracts the thermal
energy that builds up in the off-gas treatment system from cooling
the combustion gases from the hood. The heat is rejected to the
atmosphere is a fin tube, air-cooled heat exchanger. This makes
the entire process system self-sufficient in terms of site services,
326 IN SITU TREATMENT
ELECTRICAL TRAILER
OlVCOt LOOPS
MR COMPRESSOR
(HOLDING)
TANK
PROCESS
CONTROL
PROCESS CONTROL TRAILER
HEATER
CHARCOAL
FILTERS
OFF-GAS TRAILER
Figure 3
Process Trailers for the Large-Scale In Situ Vitrification Unit
except for electrical supply. In cases where electrical supply is
remote and costly to bring in, diesel generators can be used to
supply the required electricity. Details of the large-scale process
equipment and the process capabilities are found in Buelt and
Carter.2
The normal processing rate for the large-scale system is 3 to 5
tons/hr or nominally 3 to 5 ydsJ/hr, a rate competitive with many
other remediation technologies. The average processing operation
lasts about 150 to 200 hours depending upon the depth and elec-
trode spacing, although for processing to depths of SO ft, single
processing operations can run in the range of 300 to 400 hours.
The production rate will remain constant at 3 to 5 tons during the
entire time period, resulting in a vitrified mass greater than 1,000
tons.
For routine operations on a site, all three trailers are coupled
together and moved from one processing position to another by
pulling them as a unit. The hood is moved from one position to
another with a crane. The crane also is used to assist in coupling
and uncoupling the off-gas lines. Moving from one processing
position to another takes about 16 hours; thus, a relatively high
operating efficiency can be achieved. This 16-hour interim for
movement also provides time for performing routine maintenance.
PRODUCT CHARACTERISTICS
The ability of the waste form to retain the encapsulated or in-
corporated heavy metals is of prime importance to the usefulness
of the ISV process.
The vitrified waste form has been subjected to a variety of leach
tests, including the U.S. EPA's Extraction Procedure Toridty
Test (EP Tox) and Toxic Characteristics Leach Test (TCLP). All
of these tests show a uniformly low leach rate for heavy metals of
about 5 x 10-5 g/cmVday or lower. Based on limited tests, it is
reasonable to assume that the vitrified material can be delisted
under the provisions of either the EP Tox or the TCLP
Another indication of the durability of the ISV waste form is
-------
found in a study of the weathering of obsidian, a glass-like
material physically and chemically similar to the ISV waste form.4
In the natural environment, obsidian has a hydration rate cons-
tant of 1 to 20 /tmVlOOO years.5 Using a hydration rate of 10 /*m2
and a linear rate produces a highly conservative estimate of a
1 mm hydrated depth for the ISV waste form over a 10,000-year
time span.
Data for the release of sodium from vitrified Hanford soil dur-
ing a leach test at 90 °C are available1 for durations of 7,14 and 28
days. Because the sodium is soluble in the leachate, its normalized
release is a measure of the extent of hydration of the glass and, in
particular, its normalized release divided by the density of the
glass is the depth of hydration. If the glass is assumed to hydrate
according to the same parabolic rate law as has been found for
obsidian, then the square of the depth of hydration divided by the
duration of the test should be constant. Using the data in Oma et
a/,,1 the result of this calculation increases between the 7- and
14-day data but is constant between the 14- and 28-day data. Tak-
ing this final value and using the density of the glass, the hydra-
tion rate at 90 °C appears to be about 2 /imVyr.
In the literature on field studies of obsidian hydration, the rate
is found to obey an Arrhenius relation with an activation energy
of 20 kcal/mole. Applying this to the ISV glass hydration, we can
predict rates of 5 jimVlOOO yr at 20°C (e.g., for glass exposed to
the air) and 1 /imVlOOO yr at 10°C (e.g., for glass buried under-
ground). These values are comparable to those found for obsidian
hydration rates in the field for similar average weathering
temperatures.
The long-term stability of obsidian in nature is controlled by
three mechanisms:4 alteration (weathering), devitrification (re-
crystalization) and hydration (water absorption). Review of the
literature indicates that the usual controlling mechanism is
devitrification. Studies of the mean age of natural glasses indicate
that obsidian has a mean life of about 18 million years.4 Consider-
ing the similarity of the ISV waste form to obsidian, it is
reasonable to postulate that the mean life of the vitrified material
would be on the order of 1 million years.
The ISV waste form is a glass with the atomic structure that is
random, rather than the highly structured nature of a crystalline
material. This leads to another benefit: that the fracture
mechanism is conchoidal, which means that the waste form is not
subject to significant damage by freeze/thaw mechanisms that
can accelerate natural degradation. Accelerated fracturing by a
freezing and thawing would increase the surface area and the
amount of material that could be leached into groundwater.
ECONOMIC ANALYSIS
The economics of the process have been examined under
various conditions that represent typical conditions that might be
encountered throughout the United States. While the methodol-
ogy for developing ISV cost estimates was developed and
reported1 prior to the design, fabrication and testing of the large-
scale system, the approach is still considered valid. The two key
assumptions in the initial economic projections were: (1) that the
system could be operated with two people per shift, and (2) that
the system could be moved from one processing area to another
processing area in less than 24 hours. Both of these assumptions
have been proven correct.2
Highlights of the cost estimate technique used for the initial
cost projections are summarized here; details can be obtained
from the original reference.1 The cost estimate is divided into five
main categories: (1) site costs, (2) equipment costs or capital re-
covery, (3) operations and labor, (4) electrode costs and (5) elec-
trical costs. The two factors that most significantly affect total
cost are the amount of moisture in the soil and the cost of elec-
tricity. The amount of moisture directly affects operational time
and, therefore, has a direct bearing on the labor and operations
costs. The electrical energy equivalent of the heat of vaporization
for the moisture in the soil must be supplied and the water boiled
off before vitrification can proceed.
The cost of electrical power also has a direct effect on the
operational costs. Equipment or capital recovery costs and elec-
trode costs are significant; however, they are treated as constants.
Site costs are based on nominal amounts of civil work that must
be performed, which include acquiring and placing clean backfill
in the subsidence zone.
Equipment costs or capital recovery include the costs of the ISV
system and the necessary support equipment such as a front
loader and crane for earth-moving operations and moving the
hood and trailers, respectively. There is also a nominal allowance
for extending existing power lines and installing a substation. All
equipment is assumed to have a 10-year life. The sum of the
equipment costs is multiplied by a 20% capital recovery factor
and added in as a unitized cost factor.
Operations and labor costs consist of the labor and materials
for those activities that must be performed to support normal
operations. These activities include labor time for the two
operators required to operate the system. System operation is
calculated on the basis of 24-hour continuous operations. Other
support activities include digging the holes and placing the elec-
trodes, moving the trailers and hood from one processing position
to another and performing routine maintenance operations when
the system is being moved. Also included are costs for placing the
starter material and connecting, disconnecting and testing the
electrodes. The operational cost also includes an allowance for
secondary waste disposal, i.e., treating and/or disposing the scrub
solution once per week.
Electrode costs are for the purchase of electrode materials,
which are used only once, assuming that the electrodes are left in
the melt. For operations in a chemically hazardous environment,
the electrodes can be retrieved and sold for salvage value, which is
about 20% of the original cost. For operations with a process
sludge where significant decomposition of the sludge occurs,
there is a potential for electrode reuse; however, estimating elec-
trode recovery values that are higher than the salvage value is not
conservative planning at this time.
These cost factors have been calculated and plotted in graphical
form in Fig. 4. The maximum cost for all three cases is $8.25/kW-
hr. At local electrical rates that are higher than this value, the use
of portable diesel generator power is recommended. Whether the
units are rented or purchased depends on the length of the
remediation operation and business decisions regarding future
operations. The flat rate also can be used for planning for sites
where local electrical power is unavailable and bringing in a power
300
200 -
100 -
468
Electrical Rate (C/kWhr)
Figure 4
Cost of ISV Applications
10
12
IN SITU TREATMENT 327
-------
line would be very expensive. The case for process sludges was in-
cluded to cover those situations where the sludge has a natural
radioactive component (such as radon) that must be immobilized.
PROCESS PERFORMANCE
The discussion on process performance is divided into two sec-
tions: (1) experience with hazardous wastes and (2) applications
considerations. The discussion will focus on the overall treatment
efficiency; the retention and/or destruction in the melt and the
capture and removal of the material released from the melt by the
off-gas system. The sum of the two functions represents the
overall system Destruction Removal Efficiency (DRE). The
results of the process performance testing with hazardous
materials are subdivided into two categories: metals and organics.
Metals
During the processing operations with ISV, metals are either
dissolved in the glass or incorporated in the vitreous matrix. The
three factors that have the largest effect on retention are burial
depth, solubility and vapor pressure. Burial depth has a direct
function on retention, increasing the amount of retention with in-
creased burial depth. Metals are retained in the melt as a direct
function of the solubility and inversely proportional to their
vapor pressure.
The measure of the material retained in the melt is the retention
factor, defined as:
Retention Factor = FR = [A]i/[A]e
(1)
where [A]i is the concentration of the element A initially present
and [A]e is the concentration of element A exiting the com-
ponent. This terminology is used for the retention in the melt as
well as the retention in the off-gas treatment system. The reten-
tion factor is the inverse of the quantity [1-DRE].
The effect of burial depth on retention of elements can be seen
in Fig. 5. In these pilot-scale tests, the metals were in common
chemical forms such as nitrates, fluorides and oxides. Fig. 6
shows the results of the engineering-scale tests with lead and cad-
mium. The lead shows a constantly higher retention in the melt
with increasing depth, most likely reflecting the high solubility of
lead in glass. Cadmium, which is less soluble in glass, also shows a
depth-dependent retention. When estimating retention factors for
metals in the melt or off-gas system, it is important to consider the
solubility of the metal in the glass and also the likely oxidation
state. The melt is reducing in nature, so the most likely form of
most metals is either the pure state or the lowest oxidation state
that will accommodate a stable oxide.
99.99
99.9
99
90
0.2
J_
J_
_L
1.2
0.4 0.8 0.8 1.0
BURIAL DEPTH, m
Figure 5
Element Retention vs. Burial Depth During Pilot-Scale Tests
1.4
4 I 12 It 20 24
AVBUOt imUAI. DEPTH FROM CUMFACf torn)
* 12 1C 20 24
AVtMOC KMBAl OtTTH FHOM tMVACf ICfM
Figure 6
Element Retention vs. Burial Depth During Engineering-Scale Tests
Data from other glass processes, such as melters, are not con-
sidered reliable sources in estimating retention factors because of
the difference in reducing conditions in the glass. Ruthenium in
an oxidizing environment can form RuO3 which sublimes at
about 1000°C and cause serious problems in melter off-gas treat-
ment systems. In the pilot-scale radioactive test, ruthenium ex-
hibited a retention of 99.82% or a decontamination factor (DF)
of 550. The enhanced retention because of oxidation state and
solubility is very important when assessing potential applications
to traditionally volatile metals.
Retention factors measured in pilot-scale testing are shown for
both the melt and the off-gas treatment system in Table 2. These
data allow one to predict the retention of other hazardous metals.
Results for large-scale testing show that retention continues to in-
crease with increasing depth below 1 m. An order of magnitude
increase in retention was observed when the depth was increased
from 1 to 5 m.2 The presence of combustibles can provide a path
to the surface by entraining the metals in the combustion product
or pyrolytic gases, increasing the retention fraction. The closer to
the surface, the more likely the entrained material will not be
scrubbed out by the molten glass and recaptured. Even the
decomposition of nitrates can provide an elution path if the reac-
tion occurs nears the surface.
Enhanced releases associated with combustion events are
shown in Fig. 7. These results are also from pilot-scale tests where
the simulated metals were deliberately placed with combustibles.
At each combustion event, the concentration of the metals in the
scrub solution increases measurably with a clear change in the
slope of the concentrative curve.
328 IN SITU TREATMENT
-------
Table 2
Retention Factors of Metals
Type of Metal
Particulates
Sr, Pu, U, La, Nd
Semi-Volatiles
Co, Cs, Sb, Te, Mo
Volatites
Cd.Pb
SoU
105
102
2-10
Off-Gas
105
10*
10*
Combination
lO'O
10*
105
These data are important for estimating the amount of secon-
dary waste that will be generated by contaminating the scrub solu-
tion with hazardous chemicals, necessitating potential treatment
of the scrub solution before its disposal. With a meter of clean
overburden, decontamination factors (DFs) of at least 100 can be
expected even for the volatile elements. Decontamination factors
of 1,000 and greater can be expected for the semi- and nonvolatile
metals, assuming that there is no significant quantity of com-
bustibles.
20 30
RUN TIME, h
Figure 7
Cadmium and Lead Release as a Function of Run Time
Organics
During processing, organics that are contacted by the vitrified
material are destroyed by pyrolysis. The pyrolytic gases move up-
ward through the melt and combust when contacted by the oxygen
atmosphere in the hood. The data base for processing organics has
been limited to selected organics in containers, PCBs and organics
associated with electroplating wastes. As the ISV process gains
additional acceptance as a remediation tool, the data base will
grow.
Combustible testing with organics has included up to 50 kg of
solid combustibles and 23 kg of liquid organic in a single pilot-
scale experiment. The materials were packaged in a container
such as might be found in a solid-waste burial ground. Chromato-
graphic, sample bomb and mass spectrometric analyses of the ef-
fluent from both the hood and the exhaust stack showed less than
5 x 10-3 vol% release for light hydrocarbons during peak com-
bustion periods. This level of release indicates nearly complete
pyrolysis and combustion.6
A limited number of experiments have been conducted to
define the pressure rise and rate of release associated with
organics in sealed containers. Theoretical calculations predicted
that the internal pressures would be several hundred lb/in.2, and
that the pyrolized material would produce a transient pressure
wave that would move through the melt in a few seconds. The
tests were performed using the engineering-scale system; the sealed
containers were lecture bottles, equipped with pressure sensors.
The maximum pressure observed was 32 lb/in.2; the pressure at-
tenuated over a period of 1.5 min. These data indicate that the
metal softened as the vitrified zone approached the sealed con-
tainer, and that the intrusion of the glass was slower than the
theoretical maximum rate. This could be a scaling effect, related
to the relatively high viscosity of the glass. Intrusion into a buried
55-gal drum is expected to be very rapid. The organics in the con-
tainers were completely destroyed.
An engineering-scale test was conducted using soils con-
taminated with 500 ppm of PCBs. The data from the test showed
that the process destruction was slightly greater than 99.9%. The
small amount of material released to the off-gas system was effec-
tively removed, yielding an overall system ORE of > 99.9999%.
Analysis of the vitrified block showed that there were no residual
PCBs; considering the processing temperature, the data are
reasonable. The soil adjacent to the vitrified area was examined
for PCBs; limited quantities were detected (0.7 ppm of PCBs).
These data indicate that the vitrification rate is greater than the
PCB diffusion rate and that migration away from the vitrification
zone during processing is not a significant concern.
Engineering-scale tests on electroplating wastes have shown
that the destruction efficiency for contaminated soils is > 97%
for the process even when the contaminated soil is not covered
with a layer of clean soil. Other tests have shown that an uncon-
taminated layer of soil increases the efficiency of the process to
greater than 99.99%. Additional removal can be obtained by the
use of charcoal filters in the off-gas treatment system, thus im-
proving the overall system DRE.
The observed system DREs indicate that the process has a
potential to be a very valuable tool for the remediation of sites
that contain both organic and metallic hazardous wastes. While
the results are promising, feasibility testing to confirm applicabil-
ity is strongly recommended prior to any commitment to deploy
the process on a site that contains significant quantities of
organics that are unconfined in the soil column.
APPLICATIONS CONSIDERATIONS
Prior to exploring various hazardous waste application
scenarios, the operational capabilities and limitations of the large-
scale system will be reviewed. The capabilities of the large-scale
system to treat various soil characteristics and inclusions can
logically be divided into two categories: (1) capabilities of the
power supply system and (2) capabilities of the off-gas system to
maintain a negative pressure during transient events. The
capabilities of the electrical system in terms of electrode width,
depth and shape have been reported in Oma et a/.1 and Buelt and
Carter.2
The two factors that can influence the ability of the power sup-
ply system are the presence of groundwater and buried metals. As
a general rule, soils having low permeabilities do not inhibit the
ISV process even in the water table because the rate of recharge is
not significant in terms of the processing rate. The melt proceeds
at a rate of about 3 to 6 in./hr. Thus, soils with permeabilities in
the range of 10-5 to 10-9 are considered able to be vitrified even
IN SITU TREATMENT 329
-------
in the presence of ground water or in the water table. Soils with
permeabilities in the range of 10-5 to 10 ~4 are considered
marginal. Soils with permeabilities higher than 10 ~4 are difficult
to vitrify in the water table unless additional steps are taken, such
as drawing the local water table down by pumping and installing
underground barriers.
The presence of buried metals can result in a conduction path
that would lead to electrical shorting between the electrodes; how-
ever, the processing margins are quite generous. Buried metals
that occupy up to 90% of the linear distance between the elec-
trodes can be accommodated without suppressing the voltage be-
tween the electrodes. Also, once melted, the impact of the metal is
less significant. Miscellaneous buried metal, such as drums,
should have little or no effect on the ability to process a candidate
site. Metal limits are currently 5 wt% of the melt. This is a large
fraction when considering drums of waste. In fact, drums con-
taining hazardous and/or classified wastes can be placed in an ar-
ray that will take advantage of the melt configuration. Such an
array is shown in Fig. 8. Here, the metal content of the 273 drums
is 1.5% of the melt weight, leaving considerable capacity for
miscellaneous metal contained within the drums.
ACCEPTABLE CONDITIONS 90% UNEAR DISTANCE * 5 wt%
DDDD
D
D
D f
D
D
METAL «rt - I 6% Of MELT MASS
Figure 8
Utilization of 1SV for Buried Metals
Large-Scale Designed to Contain Rapid
Gas Releases
MolUn
Soil
Molten
Soil
Combuctiblet
M«Ul Container
Combuttibl* Volumt
Molten
Figure 9
Gas-Generating Configurations
Schematically, the capacity of the off-gas system to contain the
gas resulting from the processing event is shown in Fig. 10. These
capacities are representative of what might be encountered in a
solid-waste burial ground. The release of the gas is a transient
event, ending in about 1 minute. Therefore, once the transient
event has passed, the system still has the capacity to handle
another transient event. These are time-order limits, not
cumulative capacities.
9*00 **l* Of OEITK
Oft 7 wl%
MOOKrfOT DEPTH
Capacity of the off-gas system to maintain a negative pressure
during processing, thus preventing the spread of contamination
or resulting in fugitive emissions, is a function of the gas genera-
tion rate within the processing area. Gas generation resulting
from the decomposition of humus and other natural chemicals
within the soil is considered insignificant. Gas generating situa-
tions are generically shown in Fig. 9. These represent the intru-
sions of the molten glass into void spaces. Such intrusions result
in release of the entrapped air, penetration of a drum that con-
tains combustible materials and intrusion into soil inclusions that
contain combustible materials, either solids or liquids.
Figure 10
Combustible Limits for 1SV Processing
The ISV process is particularly well suited to in-place disposal
of hazardous waste. The toxic heavy metals are encapsulated or
incorporated into the glass, and the organics in containers are
destroyed. Certain inorganic compounds such as nitrates also are
destroyed by reducing the compound to the diatomic gases by the
temperature and reducing conditions of the melt. Sulfates are par-
tially decomposed; the remainder can easily be removed by the
off-gas treatment system. Fluorides are dissolved into the glass to
98% for source terms of several hundred ppm. Chlorides are dis-
330 IN SITU TREATMENT
-------
solved to the limits of solubility, which are much less than those
for fluorides, but up to 1 wtVo of the melt, which can be a large
quantity. The fluorides and chlorides not dissolved in the glass
can be scrubbed out by the off-gas treatment system, using a
caustic scrub solution.
There are five general areas where the ISV process might be ap-
plied to mixed hazardous waste: (1) contaminated soil sites, (2)
burial grounds, (3) tanks that contain a hazardous heel in the
form of either a sludge or salt cake, (4) classified waste that is
already containerized or amendable to containerization and (5)
process sludges and tailings piles that contain radioactive
materials. The application of the ISV process to contaminated
soil sites and burial grounds is similar to the previously discussed
application to general soil and burial ground sites, with the same
processing limits for metal and combustibles.
The use of ISV to destroy the hazardous heel in tanks has been
tested on the engineering scale with chemical salts. The results of
the feasibility study showed that the release was within acceptable
limits for the off-gas system and that a vitreous mass was formed.
The original tests were performed adding glass formers during the
processing to achieve a vitreous waste form. The data could be ex-
tended to the disposal of the residual heels and the tank and to im-
mobilize contaminated soil in the immediate vicinity of the tank.
By adding soil and/or rock backfill, the tank could be filled
with glass-forming materials prior to processing. This could
eliminate the concerns of tank dome and/or wall collapse iden-
tified during the original testing. Techniques for filling to the
peak of the tank dome have been developed. Electrodes would be
inserted into the tank through existing openings. The vitreous
area would grow downward and outward, encompassing the tank,
the contents and a portion of the surrounding soil. Estimates of
the maximum size tank have not been completed, but tanks in the
range of 100,000 to 300,000 gal could be permanently disposed by
this technique. The metal content of the tank structure should not
impose a processing limit.
Process sludges and tailing piles that contain natural radioac-
tive materials and hazardous chemicals can be disposed using the
ISV process. Applications that involve natural radioactive ele-
ments that result in relatively high radon fluxes at the surface are
considered potential candidates for remediation by ISV. Tests
with zirconia-lime sludges showed that the material was not only
able to be vitrified, but that the radon emanation level was re-
duced by a factor of 104 to 10s after processing. Measured radon
emanation rates were in the femto curie range. This is a practical
solution where the radon emanation levels are high, the wastes
also contain hazardous chemicals that could be leached into the
groundwater and the local infiltration rate is high. In contrast, for
large piles in remote areas and where the infiltration rate is very
low, barriers over the pile have quite effectively prevented release
of hazardous chemicals. Each potential application must be ex-
amined on its own merit.
Valuable land that is contaminated can be reclaimed by the use
of ISV processing, converting a corporate liability to a capital
asset. Old transformer areas and capacitator storage and repair
areas that are now in the business district, but contaminated with
PCBs, are examples of this concept. The ISV process has been ef-
fective on PCB-contaminated soils, achieving a system destruc-
tion removal efficiency (ORE) of 99.9999%. There will be some
limitations associated with equipment access; however, these
usually can be dealt with by a combination of equipment design
and staging operations.
Other applications considered, but not yet developed, include
shaft sealing, foundations and erosion barriers for remote loca-
tions and the generation of impermeable barrier walls to prevent
groundwater seepage into a site. Barrier generation is considered
an interim solution that would mitigate an existing hazardous
situation until a final solution could be implemented.
PROCESS STATUS AND
BENEFITS OF APPLICATION
The ISV process has been demonstrated at field-scale condi-
tions, thus eliminating the risks of scale-up. This is significant
because scale-up is the major risk area in the development and
deployment of a new technology. Technology adaptation is a
much smaller investment risk than technology development. The
applicability of the ISV process to a particular waste can be deter-
mined with existing ISV equipment for a few thousand dollars.
Thus, feasibility testing is relatively inexpensive. The focus of the
feasibility testing is the performance requirements for the off-gas
treatment system and the type and quantity of secondary waste
generated. It has already been shown that almost all of the soils
encountered are able to be vitrified, so this is not a consideration
during most feasibility testing.
The experience to date indicates that the process is ready for
deployment for soil sites contaminated with heavy metals and in-
organics. Experience with low boiling point organics that are un-
contaminated in the soil column is very limited, and feasibility
testing with actual site samples prior to application is strongly
recommended. The experience with PCBs, process sludges and
plating wastes is very encouraging. It is anticipated that the ISV
process will be used for a broader application of waste manage-
ment problems. It is also recognized that no single treatment pro-
cess is applicable to all waste management needs. Within this con-
text, ISV is a new and powerful tool that should be considered
and evaluated for radioactive, mixed hazardous and hazardous
chemical applications that fall within the treatment capabilities of
the process.
Specific benefits inherent in the ISV process are:
Safety for workers and public
Long-term durability of the waste form ( ^ 1 million years)
Applicability to a variety of soils
Cost effectiveness ($100-$250/ton for soils)
Volume reduction for sludges ( C$100/ton)
Efficient processing rates (3-5 tons/hr)
The safety aspect includes both containment during processing,
as well as the lack of potential transportation accidents that might
be involved with exhumation and off-site shipment of the waste.
The durability of the waste form is consistent with the potential
length of the foreseen hazards associated with both radioactive
and chemically hazardous materials. The projected stability of
more than 1 million years for the life of the waste form is consis-
tent with the hazard of even long-lived radioactive isotopes, such
as plutonium. While it might be argued that heavy metals have no
half lives, the waste form life is consistent with prudent en-
vironmental planning.
In summary, the applicability of the ISV process to a wide
variety of soils and wastes, combined with the process' cost-
effectiveness, are responsive to the regulatory changes that are
currently in progress, i.e., changes which emphasize the need for
on-site treatment and remediation as opposed to off-site disposal.
ACKNOWLEDGEMENT
The Pacific Northwest Laboratory is operated for the Depart-
ment of Energy by Battelle Memorial Institute.
REFERENCES
1. Oma, K.H., et al., "In Situ Vitrification of Transuranic Wastes:
Systems Evaluation and Applications Assessment," PNL-4800, Pacif-
IN SITU TREATMENT 331
-------
ic Northwest Laboratory, Richland, WA, 1983. west Laboratory, Richland, WA, 1979.
2. Buelt, J.L. and Carter, J.O., "In Situ Vitrification Large-Scale Op- 5. Larsen, T. and Langford, W.A., "Hydration of Obsidian," Nature,
erational Acceptance Test Analysis," PNL-5828, Pacific Northwest 276, 1978, 153-156.
Laboratory, Richland, WA, 1986. 6 FitzPatrick, V.F., el at., "In Situ Vitrification—A Potential Remed-
3. Buelt, J.L. and Carter, J.O., "Description and Capabilities of the ial Action Technique for Hazardous Waste," PNL-SA-12316, Pacific
Large-Scale In Situ Vitrification Process," PNL-5738, Pacific North- Northwest Laboratory, Richland, WA. 1984.
west Laboratory, Richland. WA, 1986. 7 Timmerman, C.L. and Oma, K.H., "An In Situ Vitrification Pilot-
4. Ewing, R.C. and Mocker, R.F., "Naturally Occurring Glasses: Ana- Scale Radioactive Test," PNL-5240, Pacific Northwest Laboratory,
logues for Radioactive Waste Forms," PNL-2776, Pacific North- Richland, WA, 1984.
332 IN SITU TREATMENT
-------
Aquifer Restoration via Accelerated In Situ
Biodegradation of Organic Contaminants
Paul M. Yaniga
William Smith
Groundwater Technology Inc.
Chadds Ford, Pennsylvania
ABSTRACT
Recovery of the appreciable quantities of free floating hydro-
carbons has become a proven reliable technology for minimizing
the spread or impact from subsurface hydrocarbon losses. Re-
trieval of the free floating phase does not, however, mitigate all
the associated impacts, nor does it return the aquifer use or poten-
tial use. Hence, cleanup and restoration to natural conditions
through accelerated in situ aerobic degradation of organics by
native hydrocarbon utilizing bacteria is a cost-effective alterna-
tive.
Subsurface contamination from hydrocarbons predominantly
exists in the three phases of free floating of mobile hydrocarbons,
product adsorbed onto the soil matrix and hydrocarbons dissol-
ved in the aqueous environment.
The latter two phases of adsorbed and dissolved hydrocarbon
contamination affect a greater area within the formation. The
symptomatic impacts, although less intense than free product, are
more persistent.
This paper discusses a 3-year abatement program implemented
to address hydrocarbons adsorbed/dissolved into the ground-
water system. The treatment program consisted of a combined
physical/chemical/biodegradational approach to reduce aquifer
degradation and supply potable interim portable water to the im-
pacted well owners.
The in situ biodegradation phase consisted of: (1) introduction
of clean oxygenated water from beyond the contaminated plume,
(2) addition of dissolved oxygen by mechanical air spargers, (3)
utilization of hydrogen peroxide to supply dissolved oxygen and
subsequent phase out of air spargers and (4) addition of nutrients
at prescribed doses and intervals. The net results of the work pro-
gram are a 70%-80% reduction of total hydrocarbons within the
aquifer.
INTRODUCTION
Many of the organic compounds which were developed in the
late 1920s and 1930s to serve the needs of evolving technological
societies have found their way into the environment. These com-
pounds originally developed to serve mankind have become a
nemesis. The increasing awareness of soil and groundwater de-
gradation by organic compounds is now widely recognized as a
problem of international dimension. The sources and vehicles for
the entry of these diverse compounds into the soil and ground-
water system are as varied as the contaminants.
Historically, deliberate and sometimes sanctioned disposal of
waste solvents, sludges and off spec products into landfills have
resulted in significant environmental degradation. Today, an even
more common, yet equally unintentional, source of loss of
organic chemicals to the soil and groundwater system presents
itself in the form of leakage from below ground transmission
lines and tanks used to contain these compounds. This paper dis-
cusses one such problem of soil and groundwater degradation by
benzene, toluene, xylene and certain associated inorganic param-
eters in terms of its treatment and abatement.
The key to the treatment and abatement of this particular
cleanup is the application of an in situ bioreclamation technique
which enhances the growth of existing native hydrocarbon-utiliz-
ing bacteria by means of the addition of nutrients and oxygen to
the groundwater system. This paper presents information show-
ing the superiority of oxygen transmission to the groundwater
system through the use of dilute mixes of hydrogen peroxide over
traditional mechanical air spargers.
The aquifer cleanup and abatement program also incorporates
a comprehensive physical-chemical treatment system for water
neutralization and metallic compound removal.
BACKGROUND
In this case history, the contamination problem occurred when
an undetermined amount of gasoline leaked from a below ground
storage tank. The area of the loss is underlain by approximately
6 to 7 ft of red-brown, heavy silt loam which, in turn, is under-
lain by a fractured red-brown shale and silt stone. The ground-
water table is found within the bedrock system at a depth to 20 to
25 ft below grade. The gasoline migrated through the overburden
into the bedrock groundwater system.
The resulting significant impacts of the loss included soil con-
tamination by absorbed concentrations of gasoline-type hydro-
carbons which proved to be a continuing source of organic vapors
and contamination source of low level water-soluble organic com-
pounds to groundwater. Associated changes in geochemistry also
led to increased concentrations of iron and manganese. The re-
WATER TABLE
DISSOLVED HYDROCARBONS
.GASOLINE/WATER
INTERFACE
Figure 1
Typical Impacts from Loss of Organic Chemicals
IN SITU TREATMENT 333
-------
suiting impacts affected the quality and use of 10 domestic water
supply wells. The observed impacts were typical of leaks of such
materials, except a free floating phase was absent (Fig. 1).
• RECOVERY WELL
• OBSERVATION WELL
A DOMESTIC WELL
l rti M fin
Figure 2
Water Table Contour Map
(Data Taken from Groundwater Technology Monitoring Wells)
• RECOVERY WELL
• OBSERVATION WELL
A DOMESTIC WELL
Figure 3
Isocon Map of Initial Hydrocarbon Contamination (ppm) of
Domestic Wells
• RECOVERY WEIL
• OBSERVATION WELL
A DOMESTIC WELL
I ret M rccv
Figure 3 A
Isocon Map Manganese Concentration (ppm)
(November 1981)
• RECOVERY WELL
• OBSERVATION WELL
A DOMESTIC WELL
Figure 3B
Isocon Map Iron Concentration (ppm)
(November 1981)
PROBLEM ASSESSMENT
The areal extent and magnitude of the organic contamination
was determined via a combined program of sampling and analysis
of domestic wells and the installation of 12 additional observa-
tion wells.
The data showed a plume of dissolved organics and inorganics
334 IN SITU TREATMENT
-------
that extended approximately 200 to 250 ft in a north-south direc-
tion and 300 to 350 ft in an east-west direction. The east-west
plume elongation proved a function of local geologic structure
and direction of groundwater movement (Fig. 2 and 3). Contam-
inant concentrations ranged from less than the detection limit (10
jig/1) to greater than 15 mg/1 for gasoline type hydrocarbons.
Iron and manganese concentrations ranged from 0.1 mg/1 to 6.7
mg/1 and 0.2 mg/1 to 12.0 mg/1, respectively (Fig. 3A and 3B).
DEVELOPMENT OF CONTAMINANT
ABATEMENT PROGRAM
As the organic/inorganic contamination was spread through a
significant portion of the aquifer, a comprehensive aquifer res-
toration program was required to restore the groundwater to
usable quality. The cleanup was directed at the organic com-
pounds, as they were deemed the most unacceptable in the drink-
ing water supply. The presence of the organic compounds and
subsequent changes in aquifer geochemistry also appeared re-
sponsible for the increased leaching and presence in drinking
water of the two trace metals. The program developed was based
on both field and laboratory bacterial cultures (Nocardia and
Pseudomonas) that were hosting and degrading the organic com-
pounds present. Studies further indicated that the greatest limita-
tions on the rate of degradation by the aerobic bacteria were the
amounts of oxygen and certain inorganic nutrients.
A system of contaminant plume and water table manipula-
tion via pumping, dissolved organic removal of the pumped water
by air stripping and accelerated in situ biodegradation of ad-
sorbed dissolved phases by physical addition of oxygen and nu-
trients was designed (Fig. 4).
Prior to operation of the system for aquifer restoration and
removal of the organics, it was necessary to develop a means of
supplying the impacted residents with aesthetically usable water
beyond their bottled water supply.
Further chemical analysis, beyond organic scans, showed a
need to address both inorganic and organic compounds. The
analytical results dictated the development of a physical/chem-
ical treatment process that relied on neutralization, carbon ad-
sorption, ion exchange and biological treatment (Fig. 5). This
combination of treatment steps produced aesthetically usable
water, which was free of any residual dissolved organic com-
pounds.
Notes:
1. Neutralizing fitter; preliminary sediment, iron and manganese removal.
2-2a. Taste and odor filter; activated charcoal with high surface area for removal of taste and
odor (removal of hydrocarbons).
3. Portable ion exchange units (in parallel); removal of hardness and further iron and manga-
nese removal.
4. Ultra violet light; bacteriological treatment unit for coliform treatment.
Figure 5
Schematic: Water Treatment System to Improve Aesthetic Water Quality
in Residences Affected by Suspect Hydrocarbon Contamination
STATION
r«
f
RECOVERY WELL
OBSERVATION WELL
DOMESTIC WELL
AIR SPARGING WELL
AIR COMPRESSOR
INFILTRATION GALLERY
AIR STRIPPING TOWER
AREA OF CONTAMINATION
AIR LINE
WATER DISCHARGE LINE
JL
Figure 4
Schematic of Bioreclamation System
INITIATION OF ABATEMENT/
AQUIFER RESTORATION
In implementing the designed program, the practical approach
adopted took into account the nature of the problem, the source,
the configuration of the plume, the nature of the groundwater
system and the character of the community. The program devel-
opment was carried out in a logical sequence which included:
• Development, installation and shakedown testing of the physi-
cal/chemical water treatment system on domestic wells
• Excavation and disposal of highly contaminated soil in the
tank pit area
• Conversion of the tank pit, via backfill with crushed stone, to
an infiltration gallery
• Construction of a pumping well located in the center of the
plume to control the water table and movement of contami-
nated groundwater
• Pump testing of the central well to allow calculations of the
expected radius of influence to assess the well's capability to
control the migration of the plume
• Construction and erection of an air stripper for volatile organic
removal
• Development of nutrient mix ratios for addition to the ground-
water system to accelerate hydrocarbon-utilizing bacteria for
reduction of the fugitive organics
• Development of mechanical means of air supply and air sparg-
ing to deliver oxygen into the groundwater system; previously
existing observation wells were used as air sparging and nutrient
addition points
• Development and construction of a nutrient mix tank in the
area of the infiltration gallery for batch feed of nutrients to
the contaminated tank pit area
• Shakedown testing of the system to ensure operational effic-
iency in the control of the organic plume
IN SITU TREATMENT 335
-------
The system, as designed, was to begin pumping at the central
well, inducing water in the plume to flow radially inward from
the periphery. The recovered contaminated water was then to be
passed through an air stripping tower where volatile organics were
to be removed and oxygen was to be added. Nutrients were then
to be added to the hydrocarbon-free/oxygen-rich water, which
was then to flow through the contaminated soils and ground-
water system, thus accelerating the in situ reduction of organic
compounds via the increased numbers of hydrocarbon-utilizing
bacteria.
The control of the spread of nutrients, oxygen and micro-
organisms was to be maintained by the central pumping well. The
treatment for the organics was to be enhanced via the addition
of oxygen and nutrients on the periphery of the plume. This water
was then to be pulled back through the contaminated zone to the
central plumbing well.
RESULTS OF THE ABATEMENT
PROGRAM
The results of the aquifer restoration program were quite good.
The physical/chemical treatment system for the domestic wells
functioned well, producing a reliably usable water supply (Fig.
5A and 5B). As the total aquifer cleanup program moved for-
ward, decreased frequency of treatment media exchange (i.e.,
WELL V
WELL U
WELL B
'991 NOVEMBER
WELL V
KEY
I • INFLUENT
E • EFFLUENT
1991 NO/EMBER
WELL L
WELL P
IMI NOVEMBER
Figure 5B
Iron Concentrations Pre & Post Physical-Chemical Treatment
WELL M
WELL B
E
0
1981 NOVEMBER
O 0
t- K>
WELL L
WELL P
1981 NOVEMBER
!»•! NOVEMBER
Figure 5A
Manganese Concentration Pre & Post Physical-Chemical Treatment
activated carbon) was required, thus attesting to overall contam-
inant reduction. The central pumping well contained and con-
trolled the plume configuration like an in situ treatment vessel
(Fig. 6). The air stripping tower, subsequent to shakedown test-
ing, performed as designed with greater than 98% to 99% effic-
iency for removal of volatile organics (Fig. 7). The designed infil-
tration gallery, located in the former tank pit, proved functional
in accepting the 30,000 to 35,000 gal/day of treated oxygen- and
nutrient-rich water. Heavy spring rains and recharge caused some
concern regarding overtopping of the gallery which, however, did
not occur.
The air sparging system, consisting of mechanical air compres-
sors, air lines and down well diffusers, proved to be effective to
partially effective in delivering needed oxygen to peripheral areas
of the plume outside the infiltration gallery. The major limita-
tions were the maximum quantity of oxygen that could be in-
duced into the groundwater system (10 mg/1) at the sparging
point and the fouling/plugging of the sparging points by the
development of thick biological growths. These two items pre-
cluded optimum oxygen transfer to the fractured bedrock sys-
tem and required frequent mechanical cleaning.
Despite non-optimum conditions, cleanup over the first 11
months resulted in a 50% to 85% reduction in organic contam-
inants. Several wells had no organic contaminants at this point
(Fig. 8 and 9).
While pleased with the overall results, the rate of oxygen trans-
fer was limiting microorganism growth rates and lengthening the
336 IN SITU TREATMENT
-------
Figure 6
Water Table Gradient Subsequent to Start-Up
(Data Taken from Groundwater Technology Monitoring Wells)
NOTE' SAMPLES WERE RETRIEVED BUT NOT
ANALYZED DURING SEPT TO DEC 1962.
MONTHLY SAMPLINQ AND ANALYSIS PRO-
GRAM WILL CONTINUE IN JAN 198).
INFLUENT
— EFFLUENT
(DATA FROM INFRA-RED PROCEDURE)
DATE OF SAMPLING
Figure 7
Total Hydrocarbon Concentrations for Air Stripping Tower
project restoration time; therefore, a program to accelerate this
problem was developed. The program involved a comprehensive
approach that included:
• Laboratory research
• Field studies
• Further hydrogeologic and engineering assessment
• Information/educational meetings and contact with represen-
tatives of the community and regulatory agencies
WELL 3
fKPT It NOV
1981
4 FEe 4 MAM
1982
O
ffi
WELL 2
fh
• JAM 4 FCI 4 HAH
1982
WELL 9
n n
SEPT I* NOV
1981
fJM I FES 4
1962
4 MAR
4
I-
O
WELL 6
tSEPT W HOV
1981
n.rrfl fin
M HOV f4tN 4FEB4MM SEPT 1C NOV
4FEB4HM
1982
DATE
WELL 0
nn
OF
1981
SAMPLING
f EB 4 MAft
1982
Figure 8
Total Hydrocarbon Concentrations for Core Homes
The result of the applied efforts was the development of a com-
prehensive approach to deliver increased quantities of oxygen to
the groundwater system via the trickle feed and disassociation of
dilute concentrations of hydrogen peroxide. Laboratory studies
were conducted jointly by R.L. Raymond and FMC (Richard
A. Brown). Use of hydrogen peroxide increased bacterial num-
bers and subsequently the rate of hydrocarbon reduction. Field
studies by R.L. Raymond also showed similar results. In the
development of the handling, delivery and application techniques
for hydrogen peroxide, the experience of FMC Corporation was
most valuable.
Laboratory and specific field trials at the project site showed
favorable results. One specific area of the site, located in a down
dip area from the origin of the contamination, proved trouble-
some in maintaining a sufficiently high dissolved oxygen rate to
support the aerobic biodegradation of the fugitive organics. As a
means of testing the new oxygen diffusion technique under worst
case conditions, a 5-gal batch of peroxide at a 100 mg/1 concen-
tration was added to a point on the periphery of the plume, which
was approximately 40 ft from the closest sampling location to-
ward the pumping well. The test was initiated with the central
pumping well in operation, to induce flow of water and hydrogen
peroxide to it; dissolved oxygen increased from 0.5 to 8.0 mg/1
in a 24-hr period. The increase in dissolved oxygen also stimu-
lated an increase in microbiological activity and a decrease in
hydrocarbon concentrations.
IN SITU TREATMENT 337
-------
• RECOVERY WELL
• OBSERVATION WELL
A DOMESTIC WELL
2 res M rtCT
• MCOVEKY WILL
• OBSfRvlTIOH WELL
A DOMESTIC WELL
t ft* M rtCT
Figure 9
Isocon Map of Hydrocarbon Contamination (ppm) of Domestic Wells
10 Months after Start-Up
Figure 10
Isocon Map of Hydrocarbon Contamination (ppm) of Domestic Wells
(After Hydrogen Peroxide Addition)
The concentration of hydrogen peroxide used in the ongoing
program for enhanced bioreclamation has been 100 mg/1, yield-
ing 50 mg/1 of dissolved oxygen for uptake and utilization by
the microbiological community. Hydrogen peroxide currently is
being added to the groundwater system at the site, both at the in-
filtration gallery and former air sparging wells. An added bene-
fit of hydrogen peroxide use in the wells is that when introduced
to the well bore at 100 mg/1, it keeps the well free of heavy bio-
growth, thus allowing even and quick transmission of needed
oxygen to the impacted areas of the groundwater system. The
most recent results from the site show that overall hydrocarbon
concentration levels have declined in the core area, with only five
homeowner wells still showing degradation (Fig. 10).
CONCLUSIONS
The applied techniques of physical/chemical treatment of
domestic well water combined with groundwater manipulation
via a pumping well, air stripping for volatile organic removal
and enhanced biostimulation/bioreclamation of groundwater sys-
tems contaminated by organic compounds proved a most applic-
able and cost-effective technique. Limitations of oxygen transfer
critical to aerobic decomposition of the organic contaminants can
be overcome by the application of a superior oxygen donor, such
as hydrogen peroxide.
BIBLIOGRAPHY
1. American Petroleum Institute, "The Migration of Petroleum Pro-
ducts in Soil and Groundwater—Principl.es and Countermeasures,"
API Publication No. 4149, 1972.
2. DePastrobich, T.C., Barndat, Y., Bat el, R., Chiarelli, A. and
Fussell, D., "Pollution of Groundwater from Oil Pollution," Con-
cawe the Hague, Netherlands, 1-18. 1979.
3. Jamison, V.W., Raymond, R.L. and Hudson, J.O., "Biodegrada-
tion of High Octance Gasoline." Proc. Third International Biode-
gradation Symposium. Applied Science Publishers, 1976.
4. Kramer, W.N., "Groundwater Pollution from Gasoline,'' Ground-
water Monitoring Rev. 2(2).
5. Litchfield, Jf.H. and Clark. L.E., "Bacterial Activity in Ground-
waters Containing Petroleum Products," API Publication No. 4211,
1973.
6. Raymond, R.L.. Jamison, V.W. and Hudson, J.O., "Beneficial
Stimulation of Bacterial Activity in Groundwater Containing Petrol-
eum Products."
7. Suntech, Inc., "Vapors Invade School: Bioreclamation Process
Clean Up Groundwater," Petroleum Marketer (July/August), 1978.
8. Wheatley, S., "Alternatives in Decontamination for Hydrocarbon-
Contaminated Aquifers," Groundwater Monitoring Rev., Fall,
1982.
9. Yaniga, P., "Alternatives in Decontamination for Hydrocarbon
Contaminated Aquifers," Groundwater Monitoring Rev., Fall, 1982.
10. Yaniga, P. and Cisneros, R., "Advanced Techniques in Containment
and Retrieval of Refined Petroleum Hydrocarbons from Ground-
water," DTOL Federal, Venezuela, South America. UPADI 82,
Proc. of the XVII Congress of the Pan American Federation of
Engineering Societies, 1982.
11. Yaniga, P. and Demko, D., "Hydrocarbon Contamination of Car-
bonate Aquifers: Assessment and Abatement," Proc. of the Third
National Symposium on Aquifer Restoration and Groundwater
Monitoring, National Water Well Association, Worthington, OH,
1983.
338 IN SITU TREATMENT
-------
Operation of a Light Hydrocarbon Recovery System:
Theory, Practical Approach and Case History
Robert M. Galbraith
IT Corporation
Edison, New Jersey
John W. Schweizer, P.E.
IT Corporation
Martinez, California
ABSTRACT
Light hydrocarbon recovery systems can have a wide range of
recovery well designs and equipment arrangements to meet an
equally large variety of geologic situations. However, the prin-
ciples of operation and data management for all recovery systems
are simple and easy to apply to all situations and equipment con-
figurations. The piezometric surface is determined for the water
and free hydrocarbons in the monitor wells. This surface is then
systematically controlled to prevent the further spread of liability
and to recover the free hydrocarbons. The determination of the
piezometric surface and its use as the control surface automat-
ically compensates for unknown factors such as the permeability
of the soil with respect to the hydrocarbon, relative flow veloci-
ties and volume of material spilled.
INTRODUCTION
The purpose of a gasoline recovery system is to limit the ex-
posure to liability and remove the gasoline from the subsurface.
The conditions under which this is achieved vary with each site;
however, several general conditions are present in all cases.
Gravity is the driving force that causes the gasoline to spread
out on the surface of the water table, and gravity is the only force
used to collect the gasoline when the recovery system is imple-
mented. The conditions that influence the spread of the plume are
the permeability of the soils with respect to gasoline and the shape
of the water table surface.
If the water table is flat and groundwater flow velocities are
low, the gasoline will spread in all directions with a slight bias to-
ward the direction in which the groundwater is moving. If the
water table has a steep slope and groundwater velocities are high,
then the plume will stream out in the direction of groundwater
flow unless there is a large difference between the permeability of
the soils with respect to water and gasoline.
To achieve its purpose, a gasoline recovery system must influ-
ence the shape of the water table enough to stop the spread of the
plume and direct the flow of gasoline to a location where it can
be pumped out of the groundl This process is accomplished by
pumping a well sufficiently fast to create a cone of depression.
Once this cone of depression is created, the gasoline will accum-
ulate in the depression wells and can be removed from the
ground. As the plume gets smaller, the depression level is raised in
stages until finally there is no gasoline accumulating in the well
and the monitor wells show only a sheen or no gasoline at all.
After the system is turned off, monitoring continues for a
quarter. If at the end of that time no new accumulation of gaso-
line is found, then the recovery system has done its job.
RECOVERY WELL LOCATION
Determining the location of the recovery well is relatively easy
if there are enough monitor wells to define the extent of the plume
and the groundwater gradient. The purpose of the recovery well is
to create a hydraulic barrier that will prevent the further spread of
the free hydrocarbon plume and collect the hydrocarbons for re-
moval from the subsurface. The hydraulic barrier can be pro-
duced by one well drawing the water table way down or by mul-
tiple wells with each providing a small cone of depression and thus
collectively creating a hydraulic barrier. Since the purpose of the
recovery well is to control the movement of hydrocarbons float-
ing on the water table rather than to produce a large volume of
water, multiple wells or a trench collector system are preferable to
a single well in controlling large plumes.
Multiple well systems have the disadvantage of requiring
pumps, piping, electrical connections and pump controllers for
each well. This duplication of equipment is very expensive to in-
stall and adds to the operation and maintenance costs. Storage
tanks for the hydrocarbons may be fed by more than one well,
and water from multiple wells can be treated in one system. To
avoid excessive costs, a collector trench with one or more sumps
is preferred over multiple well systems. The installation of the
collector trench generally is not practical where the water table is
deeper than about 8 ft below land surface. In order to create a
hydraulic barrier, the depression level must be several feet below
the normal water table. If the water table is 8 feet deep, then the
trench has to be 12 ft deep and the sump where the pumps are in-
stalled has to be several feet deeper than the trench.
The location of the well, wells or trench should be on the down-
gradient side of the plume where the monitor well data indicate
the presence of the greatest amount of hydrocarbons. The
hydraulic barrier must have a wide enough area of influence to
reverse the flow of hydrocarbons that lie on the downgradient
side of the barrier.
STAGES OF OPERATION OF
THE RECOVERY WELL
The critical factor in the operation of the recovery well is main-
taining the hydraulic barrier. Hydrocarbon removal is a secon-
dary factor. By maintaining the hydraulic barrier, the plume is
controlled so that there is no increase in liability. Maintaining
the hydraulic barrier causes the soils to dewater, thus improving
their permeability with respect to hydrocarbons and improving
the rate at which they will flow to the recovery well. Experience
has shown that the rate of hydrocarbon accumulation in the re-
covery well is often greatest in the dryest months of the year.
When the soils are dry, the permeability with respect to hydro-
carbons increases dramatically. The recovery operation in areas
where rainfall is relatively constant throughout the year may take
longer than in areas where there are strong seasonal differences in
soil moisture content.
IN SITU TREATMENT 339
-------
Fig. 1 illustrates the stages of operation of a recovery well. The
initial depression level in the recovery well is set so that the cone
of depression controls the edge of the plume. The initial depres-
sion level has two immediate effects: first, the migration of the
plume is controlled and second, the hydrocarbons that were on
the water table surface are now migrating downward in the
partially saturated soils above the new water table surface. In Fig.
1, hydrocarbons that were at point "A" prior to turning the de-
pression pump on must travel to point "B" before resuming their
migration on the water table to the recovery well. This downward
migration can take from several days to weeks. During this re-
equilibration period there often is little or no hydrocarbon accum-
ulation in the recovery well, and the installation can appear to be
a failure.
Figure 1
Stages of Recovery Well Operation
As the plume diminishes in lateral extent, the depression level
may be raised in the recovery well as illustrated in Fig. 1. The de-
pression level should be raised cautiously. If it is raised too quick-
ly, there may be a loss of plume control, and the recovery well
will no longer limit one's liability. If plume control is lost, then
the lower depression level will have to be used again and, in
essence, the recovery operation will start from the beginning.
Having a large number of monitor wells can prevent such errors
that cost far more than the cost of a few monitor wells.
As the plume continues to diminish, the depression level can
be raised until the free hydrocarbons no longer accumulate in the
recovery well and the cleanup is complete. The depth of the initial
depression level and the number of times the depression level is
raised are decisions that must be made for each site and its spe-
cific conditions. Although each site will have its own peculiari-
ties, this approach will work under all conditions.
RECOVERY WELL EQUIPMENT
There are potentially two complete pumping systems that may
be installed in a recovery well. The critical system is the ground-
water depression pump and its controllers. The second system is
the hydrocarbon removal system. A variety of manufacturers
make complete systems, or the components can be bought sep-
arately and combined into a custom system.
Groundwater Pumping
The basic requirement is that the system is reliable. The de-
pression pump will be required to maintain the cone of depression
for at least 6 months and more likely several years before the
cleanup is complete. Each pump or controller failure will result
in the temporary loss of control of the plume and a return to the
beginning of the recovery effort.
The depression pump should be adequately sized for the flow
rate and heads resistance in the piping system. The seals and wir-
ing in the pump should be resistant to attack by hydrocarbons.
The depression pump control should be based on the hydrocar-
bon/water interface in the well. This interface should not get
close to the pump intake to cause raw hydrocarbon to be re-
moved with the water; therefore a second low water shutoff sen-
sor should be installed in the well in addition to the normal de-
pression level sensor.
The water from the depression pump must be treated and dis-
charged in accordance with local regulations. Fig. 2 shows the
components of a well designed depression pump system. A flow
meter and site glass are installed in the piping from the well to
allow one to monitor the recovery effort's progress. An oil/water
separator tank is included in the piping system as a fail safe pro-
tection against discharging raw hydrocarbons. Discharge is from
the bottom of the tank through a piping loop with an anti-siphon-
ing vent. This loop is installed at a height that assures that if
hydrocarbons are pumped to the tank, the high level shutoff will
be triggered before the hydrocarbons reach a level where they
will be discharged. The height of the loop is therefore dependent
on the density of the hydrocarbons involved.
The least costly alternative for water disposal is to a sanitary
sewer system. In this instance, the oil/water separator is very im-
portant because it prevents the discharge of raw (hydrocarbon)
product to the sewer, which may result in a greater liability than
the original spill. Where the recovered water is reinjected into the
ground, the separator is very important as it assures that the
hydrocarbons are not simply transferred from one location in the
subsurface to another.
Hydrocarbon Removal
Hydrocarbons are removed by pumping or skimming the free
phase of hydrocarbons off the water surface in the recovery well.
This activity is almost independent of the depression pumping.
The choice of manual, automatic or semiautomatic systems is
available. Again, a judgment must be made as to which system is
best suited for the situation. Where large volumes of gasoline are
expected to flow to the well, an automatic skimmer or pump is
best for the job. Automatic systems do require a complicated set
of controls and sensors which require cleaning and maintenance,
a holding tank for the recovered product which must meet local
fire regulations and a well sized to accommodate all the pumps,
lines and sensors.
— HIGH WATM SHUT DOWN
LEVEL SWITCH LEVEL 6AUS
VEHTS
Figure 2
Typical System for Handling of the Pumped Water and Hydrocarbons
340 IN SITU TREATMENT
-------
Fig. 2 shows a typical arrangement for a recovery system with a
skimmer in the well to remove gasoline. Such an arrangement
requires a well on the order of 30 or more inches in diameter, and
the skimmer has a limited pumping pressure. For both of these
reasons, such systems usually are installed where the water table is
less than 15 ft below the land surface. Installations where the
water table is deeper use a down-hole pump for removing hydro-
carbons. Again, because of the need to accommodate pumps,
cables and controls for two systems, the well must be at least 10
in. in diameter.
Where the water table is deep and the amount of free gasoline
is relatively small, a single pump can be used. This pump serves
as the groundwater depression pump most of the time as the gaso-
line is allowed to accumulate in the well. When several feet of
gasoline are present, the discharge from the pump is connected
to a waste tank and the well is over pumped to remove all the
water and gasoline. The periodic removal of gasoline will become
less frequent as the plume diminishes, thus reducing operational
costs.
MANAGEMENT OF THE RECOVERY PROCESS
The subsurface conditions are determined by drilling a series of
monitor wells that penetrate the water table. The screen that is
installed in the monitor wells must extend above the water table to
allow the gasoline which moves on the water table to enter the
well. Boring logs of the soils encountered while drilling the moni-
tor wells gives an indication of the permeability of the soils and in-
dicates whether the recovery system will use wells or trenches as
the means of controlling the water table. Generally, four to seven
monitor wells can be drilled in a day. The numbers and locations
of the monitor wells are determined by such physical restraints as
the location of buildings, overhead wires and the information
provided by each borehole as it is drilled.
Unless there is strong evidence of gasoline in most of the mon-
itor wells at the time they are drilled, they will be allowed to equi-
librate for a day before fluid measurements are made. If there is
strong evidence of gasoline at the time of drilling, additional
drilling will be done on subsequent days to determine the gross
extent of the plume. After the wells have equilibrated and the
data have been analyzed, a few additional wells may be needed
to complete the delineation of the plume so that the recovery well
or wells can be effectively placed. The need for additional moni-
tor wells is determined by the number of unanswered questions
about the site:
• Is gasoline migrating along utility or sewer lines?
• Could there be a plume for a second source?
It is a judgment call for each situation, and one more well will
never hurt.
MONITOR WELL MEASUREMENT METHODS
Water Table and Hydrocarbon Monitor
Well Measurements
The measurements are made with a transparent plastic bailer
type sampler suspended on a fiberglass measuring tape. A ball
check valve in the bottom of the bailer allows a sample showing
the product thickness to be withdrawn from the well. Fig. 3 illus-
trates the measurement process. The measuring tape is attached
to the lower end of the bailer and passes up through the center of
the body of the bailer. This arrangement allows direct readings
from the tape where it passes through the top of the product layer
and at the product water interface. The length of measuring tape
in the well indicates the depth of the sampler and is recorded as
the "Tape Reference" as shown in Table 1. If the product layer
is thicker than the length of the bailer, then deeper measurements
are made until the product water interface is found. Under these
circumstances, a deeper tape reference is shown for the water
measurements than the product measurements.
EXISTING GROUND SURFACE
<%%J^^^^^^' ^
f
sTs
'-
'.
- •>
[-
1
\?v
$
j
O-
*?/ TAPE REF.
'•" —CONCRETE
" VALVE BOX
TAPE MEASURE
•*— SLOTTED PVC CASING
TRANSPARENT SAMPLER
_ TOP OF PRODlim
"^PRODUCT /WATER
INTERFACE
•« • 0" ON TAPE
Figure 3
Typical Monitor Well Measurement Process
Table 1
Water Levels and Product Thickness Readings Taken in a Monitor Well
Dirty Dunbar, Fr*«ontp CA
1O/14/B3
kii
h.
1
2
10
11
12
13
14
IS
II
17
II
If
20
21
22
23
24
Ulttr
lift
Irf.
.80
.10
.70
.20
.40
It 0» M
.30
i.fO
1.50
7.30
7.30
I.f0
1.20
1.20
7.40
1.40
I.fO
1.50
7.fO
8.70
8.40
7.30
7.80
7.30
25 h Ml.
*tl4iHi Prefect Intlmi
lift
Int.
.13
.14
.48
.55
.73
11 tot
.2f
.11
.38
.48
.20
.30
.50
.2f
.75
.13
.25
.27
.25
.77
.33
.51
.70
.45
Ikttr
8tftk
7.37
8.41
1.22
1.15
8.17
to*.
7.01
l.2t
1.12
1.82
7.10
1.40
5.70
5.11
1.15
5.75
1.15
8.21
7.15
7.f3
1.07
1.74
7.10
1.85
Tipt
Itf.
.80
.20
.70
.20
.20
.20
.30
l.»
1.50
7.30
7.30
I.fO
1.20
1.20
7.40
1.40
I.fO
8.00
7.W
8.70
1.40
7.30
7.80
7.30
TIM
till.
.78
.41
.U
.00
.75
.3f
.00
.00
.00
.00
.00
.00
.00
.00
.18
.34
.20
.32
.00
.00
.38
.00
.00
fell jnt trlllri.
Pro**! Itl
Itotk h
7.02
1.74
1.10
.00
1.45
1.81
.00
.00
.00
.00 1
Cllcul'ttd Vilun in Ftft
litiu ! Predict
Elnitic* ! Tkickntil
20.37
20.44
lf.3l
20.04
20.18
20.51
20.81
20.15
11. »1
1 20.48
.00 11 20. W
.00 1
.00 1
i 20.14
3 11.54
.00 14 11. H
.00 1
5.72 1
1.51 1
S ».32
1 11.25
7 11.91
7.80 18 21.11
7.51 1
.00 2
t 21.15
0 21.12
.00 21 11.15
1.72 2
2 20.00
.00 23 20.30
.00 2
4 20.08
25 11.17
.35
1.72
.12
.00
2.22
> 3. If
.00
.00
.00
.00
.00
.00
.00
.00
.00
.03
.Of
.41
.07
.00
.00
.02
.00
.00
llttr
ELn.
13.00
11.18
13.01
13.31
11.71
n
13.80
13.81
13.77
13.11
13.51
13.74
ll.M
13.47
13.17
13.50
13.11
12.99
13.50
13. If
11.08
13.21
13.20
13.23
riiioittric
ElmtloH
13.27
13.21
13.18
13.31
13.40
•n
13.80
13.81
13.77
I3.U
11.51
13.74
13.80
13.47
11.17
13.32
13.23
11.21
11.55
13.11
11.08
13.28
13.20
11.23
Product
an.
13.33
13.70
13.21
.00
13. f3
> 3.11
.00
.00
.00
.00
.00
.00
.00
.00
.00
13.51
13.25
13.31
13.57
.00
.00
13.21
.00
.00
The depth to water and depth to product are calculated from
the tape readings and are shown in the fourth and seventh col-
umns in Table 1. The datum elevation is the reference elevation
for the top of the casing on the well where the tape reference was
noted. The last four columns of Table 1 show the calculated val-
IN SITU TREATMENT 341
-------
ues for product thickness, water elevation, piezometric elevation
and product elevation. The product thickness is the difference
between the depth to water and the depth to product. The water
elevation is the datum elevation less the depth to water. If product
is present, the piezometric surface is determined for gasoline
plumes by multiplying the product thickness by 0.8 and adding
the result to the water elevation. The density of gasoline is
approximately 0.8, and this calculation corrects for the difference
in density and provides a value that would be the water table sur-
face if no gasoline were present. The product elevation is deter-
mined by subtracting the depth to product from the datum eleva-
tion.
Piezometric Surface Map
The piezometric map is a representation of what the water table
surface would be if there were no gasoline in the wells and is based
on the density of the hydrocarbon in the well. The piezometric
surface indicates static head in the wells which reflects the pres-
sure gradients that determine the direction in which groundwater
will move. The gasoline usually will follow these gradients, and
the location of the recovery well is based on the shape of the
piezometric surface. The depression well should be located where
it will intercept the leading edge of the plume and take advantage
of natural gradients to minimize the amount of water that will be
pumped.
Product Thickness Map
The product thickness map shows the thickness of the gasoline
132-
131-
130-
128-
128-
127-
126-
&125-
u>
z
124.
5 123-
122-
121-
120-
110-
118 -
LEGEND:
TOP OF PRODUCT
PIEZOMFTRIC SURFACE
—— TOP OF WATER
PRODUCT THICKNESS
@
NOV DECEMBER
1082
0® ©@ ®
JANUARY FEB
1083
o
I
•©
column in each of the monitor wells. The thickness of gasoline in
a well does not reflect the thickness of the soil that is saturated
with gasoline but does indicate the relative abundance and mobil-
ity of the gasoline in the vicinity of the well.
Hydrograph
The hydrographs present the data from one well and show how
the fluid levels and gasoline thickness have changed with time.
Fig. 4 is a hydrograph for a well and illustrates the .changes that
have occurred in the well since monitoring began in December.
Hydrographs make small changes and the development of trends
more apparent than the maps do, while the maps show how the
changes occur spatially.
CASE HISTORY
The following case history involving two service stations is illus-
trated in Fig. 5 through 9. Service Station A was our client. In
the course of defining the plume from a leak at Station A, we dis-
covered an equally large amount of gasoline in the ground on the
west side of Station B (Fig. 5). The two service stations are sep-
arated by a 4-lane highway and are bounded on the east by a 6-
lane highway. Our task was to recover the gasoline under our
client's station and not bring the plume from the other station
onto our client's property. We followed the procedures explained
in this report using two recovery wells.
LEGEND:
® MONITOR WELL
• RECOVERY WELL
Figure 4
Hydrograph for Observation Well
Figure $
Piezometric Surface Elevation in Feet 20 Days After Beginning Operation
342 IN SfTU TREATMENT
-------
N
IS
^
l)}***r*£^
/1if/jjji^^.. x>
llftJ/M.,
''«'- •////'III
\ V-'
Figure 6
Product Thickness in Feet 20 Days after Beginning Operation
LEGEND:
© MONITOR WELL
• RECOVERY WELL
Figure 7
Piezometric Surface Elevation in Feet 9 Months after Beginning Operation
The plume under Station B was mitigated by our competitor
who chose to use an approach of daily well purging. We were
allowed to collect monitor well data from both stations through-
out the recovery operation.
Fig. 5 shows the piezometric surface 20 days after the two re-
covery wells were turned on. There was a cone of depression
established for Station A to control the spread of the gasoline.
Fig. 6 shows the product thickness for both stations. The plume
under Station B was very large because there were as yet no moni-
tor wells to define the true extent of the plume.
Fig. 7 shows the piezometric surface 9 months later. The recov-
ery well located on the southeast side of Station A was turned off
at this time because a recovery well finally had been installed at
Station B. The effect of the cone of depression from the Station B
well and our recovery well would have caused the plume under
Station B to migrate to our client's property. Fig. 8 shows the
product thickness 9 months after the recovery wells were put into
operation. The plume under Station A was greatly reduced in
thickness and extent while the plume under Station B was smaller
only because wells had been installed to indicate the accurate ex-
tent of the problem.
Fig. 9 shows the product thickness map 1 year after startup of
the recovery wells. The second recovery well was turned off in
July, and the tanks were removed from the station. The local fire
marshal would not allow tank removal until the product thick-
ness around the tanks was less than 1 ft. There still were minor
amounts of gasoline in the monitor wells in the curb lanes of both
streets adjacent to Station A, but the ground under the station no
longer had any free hydrocarbons on its surface. The wells in the
streets were purged monthly for the next year and the site was
then determined to be clean. In this instance, the presence of dis-
solved hydrocarbons in the groundwater was not an issue.
Fig. 9 also shows that after a year of frequent well purging
there was still a significant amount of gasoline under Station B.
The recovery well on the property was never operated systemati-
cally. Two years after the recovery operation began, a new 2-
story office building had been built and occupied on our client's
property. The Station B property was abandoned with more than
1 ft of gasoline remaining in some monitor wells.
CONCLUSIONS
The systematic manipulation of the piezometric surface to con-
trol the migration of free hydrocarbons is a reliable and easy
method of mitigating these spills. The use of piezometric surface
data to manage the recovery compensates for the unknown
parameters of soil permeability with respect to the hydrocarbon,
flow velocities or attempts to determine the true volume of the
spill. Recovery and liability control are achieved using simple field
measurements methods.
IN SITU TREATMENT 343
-------
LEGEND:
© MONITOR WELL
• RECOVERY WELL
Figure 8
Product Thickness in Feet 9 Months after Beginning Operation
This approach has been used successfully in 15 recovery oper-
ations. It was superior when applied to a situation where the soil
and water table conditions were identical under two service sta-
LEGEND:
© MONITOR WELL
• RECOVERY WELL
Figure 9
Product Thickness in Feel I Year after Beginning Operation
lions; one station used the plume and liability control strategy
described in this paper, while the other service station used a dif-
ferent recovery approach.
344 IN SITU TREATMENT
-------
Mobile Treatment Technologies
William K. Glynn
Edward P. Kunce
Camp Dresser & McKee Inc.
Boston, Massachusetts
ABSTRACT
The role that mobile or transportable waste processing systems
will play in future Superfund site activities appears to be increas-
ing. These systems, which presently are employed to treat some
RCRA wastes, appear to apply to the treatment of CERCLA
wastes.
Mobile treatment systems usually consist of modular equip-
ment that can be brought onto a site (e.g., by truck or railcar)
and can be used on a number of different sites over the life of the
equipment. Size and configuration of the equipment may differ
considerably from the conventional equipment used in permanent
structures.
The information in this paper will provide policy planners, on-
scene coordinators and remedial managers with guidance for the
implementation of mobile treatment systems. The paper pre-
sents a review of applicable treatment technologies currently used
as mobile systems. Waste characteristics, environmental impacts,
costs and other development and implementation factors are con-
sidered in assessing the potential role of these mobile systems.
INTRODUCTION
The use of mobile or transportable technologies for the treat-
ment of hazardous wastes has shown increasing promise for appli-
cation to the CERCLA program. Some of these systems pres-
ently are being employed for the treatment of hazardous wastes
regulated under the RCRA program, while other mobile treat-
ment systems currently are being developed as pilot units. The
opportunity for technology transfer of these technologies from
RCRA to CERCLA, as well as further development from the
pilot stage, represents an important challenge to the Superfund
program.
The mobile treatment systems considered in this paper usually
consist of modular equipment that can be brought onto a site
(e.g., by truck or railcar). When the cleanup is complete, they can
be transported to a number of different sites over the life of the
equipment. Size and configuration of the equipment may vary
considerably from the conventional equipment used in perma-
nent structures. In general, the equipment is smaller than con-
ventional equipment in order to allow for mobility. One large
piece of equipment, however, may be in several parts on separate
trucks, trailers or railcars. The equipment also may consist of
several removable components in order to accommodate the
needs of several sites. Mobile treatment systems may be skid-
mounted, prepiped and prewired for fast response to emergency
situations or they may require assembly on-site before opera-
tions commence and then require disassembly prior to transport-
ing to another site.
Mobile systems show considerable promise for remedial activ-
ities at Superfund sites. These technologies can provide a perma-
nent solution with many advantages over alternatives involving
off-site transport and disposal. While the experience base is some-
what limited, interest in mobile systems is growing rapidly. The
number of venders offering viable systems has increased dramat-
ically in recent years.
Several cautions should be exercised, however, before more
resources are committed to process technologies. The complexity
of Superfund wastes, many of which have been fully integrated
into the environment for many years, has required the applica-
tion of labor intensive mobile technologies to deal with the vari-
able field conditions (i.e., the changes in waste composition and
the regulated waste effluents). Even inert materials in the con-
taminated wastes (i.e., silts, clays, debris, rocks and iron) may
create significant waste processing and handling problems.
Abrupt changes in waste composition make it very difficult to
apply process control instrumentation to these wastes. More-
over, since most mobile treatment systems are smaller than sta-
tionary systems their application to the smaller hazardous wastes
sites may be limited and prevent the mobile concept from being
the "total solution" to the cleanup of uncontrolled hazardous
wastes sites.
PAST AND PRESENT USE
The concept of using mobile treatment systems to process
water and wastes is fairly well-established. The United States De-
partment of Defense has developed and used mobile water treat-
ment units to provide potable water and to treat sewage. Addi-
tionally, many conventional wastewater treatment systems have
been modularized to the extent that small-scale systems can be
practically considered transportable (e.g., equipment on oil rigs,
ships and airplanes).
The application of the mobile concept to uncontrolled haz-
ardous waste sites is not new. Under U.S. EPA sponsorship,
mobile equipment has been developed for emergency response
and has been used to contain, collect and, in some cases, provide
preliminary treatment of accidentally released hazardous mater-
ials and contaminated groundwater. The types of mobile equip-
ment developed by the U.S. EPA for emergency responses include:
Carbon adsorption/sand filter system
Rotary kiln incineration system
In situ containment/treatment system
Soil washer system
Activated carbon regeneration system
Flocculation-sedimentation system
Reverse osmosis treatment system
Independent physical/chemical wastewater treatment system
ALTERNATIVE TECHNOLOGIES 345
-------
Experience with the use of mobile systems at Superfund sites
is limited, but the concept has been or is being incorporated for
both remedial response and waste removal. Some past and/or on-
going activities involving mobile systems at uncontrolled haz-
ardous waste sites are described in Table 1.
Tiblc 1
Mobile System Use at Uncontrolled Hazardous Waste Sites
Bridgeport. NJ
Slum Uilll Type
riTol)
i/at
Completed Aqueous/Oily Lagoon
Vaste Contaminated
vlth fell
TteatMM Technology
Physlcel/Cheolcal
Tim l««eh, HO
ACM Reclaiming, XL
U»e Canal. HT
lof Creek Farm, NJ
HcIUn, KH
Triangle Chemical, T>
Old Inger, u
riclllo Farm
Design
0»>tl>
Design
Construction
Design
Design
Design
Design
Design
Design
Completed
Pd Contaminated
Sludge/tolls
tolls Contaminated
Vlth Volatile
Organlea
Soil Contaminated
vllh Lev Levels «f
Organlcs
i Leacnate tram
Chemical Damp
Sludges/Sol ll
Contemlnetmd with
Ilgh Unit el
Organic*
Sollf Contaminated
vith Lav U.els o(
Orgsnlcs
Surface Vetore
Solli Contaminated
vllh Volatile)
Soil Contaminated
vllh VoUlllt
Orgenlce
Organlcellljr Contam-
inated Sludges 1
Solll
Phenol Conlemlnaled
Soil
Incineration
Incineration
Incineration
Plasma Art (Thermal)
Incineration
Soil WaiMni'
til tact lor,
Clwvleel Treetment
and Air Stripping
Mechanical Aeration
Mechanical
Aeration
Landfermlng
In aim blo-
degradatlon
Lee'I Faro, VI
Ulde >«»ch
Deilffn
Deil|n
Sells Containing
Lead
PCB Contaminated
Solll
Sejraour lecycllni. IM Coepleted Surface Runoff
Resolve. HA
Iruln Ufoon, PA
Oavle Landfill, PL
McAdoo Aisoc.. PA
Tysons Ouop, PA
Mo-Ccology
Coapleted PCt Contaolnated
Sludfe
Construction Acid Aaphaltlc
Studies
Oeslfn
Oesljn
Deslfo
Deslfn
Sludfes
Soil Contaminated
vllh OrianUs
loll Conlaelnated
vlth Organlct
•eavy Metal
Ilutffes i Soils
Soil Vashlnf/
Extraction
Cheelcal Trealnenl/
Kxtractlon
Physlcal/Cheailcal
Stabilisation/
Solidification
Stabilisation/
Solidification
Stabilisation/
Solidification
Stabilisation/
Solidification
Stabilisation/
Solidification
Stabilisation/
SolUKUallon
Note: Some designs hive been delayed pending roulhortutlon.
In spite of the increased use of mobile treatment systems for
both emergency responses and remedial actions at hazardous
waste sites, there are many factors that have contributed to the
very limited application of mobile systems at Superfund sites.
These factors include:
• Generally higher costs and longer periods for development and
operation
• Developmental nature of some technologies
• Local institutional issues of concern
• Limitations of capacity, materials handling or process char-
acteristics that prevent the mobile concept from being a total
solution
FUTURE USE
Land disposal of hazardous waste is becoming less acceptable
as a means of managing uncontrolled hazardous waste sites. Pol-
icymakers are realizing that land disposal does not offer a final
solution to the hazardous waste problem—rather than providing
a method of treatment, land disposal often provides only tem-
porary containment. As a result, many wastes will be restricted
from land disposal within the next 5 years. Developing alterna-
tives to land disposal is, therefore, imperative.
Cost, availability and reliability are three of the key factors
used to determine which systems are preferable to others. The
development climate with respect to these three factors appears to
be changing in favor of mobile systems. The following points
summarize some of the favorable aspects of these systems:
• As more systems are developed, cost, reliability and availabil-
ity will continually improve.
• Although several innovative mobile technologies have large
capital equipment costs, those equipment costs may be applied
to many sites and be shared by those projects.
• Mobile on-site treatment may be preferable to off-site station-
ary facilities in cases where permitting is an important issue.
The exemption of the on-site system from some permitting re-
quirements may make the mobile alternative more attractive.
• The ability to manage the waste handling, treatment and dis-
posal activities on-site has many inherent advantages for re-
medial action planners and managers.
• A number of vendors have expressed interest in developing a
mobile system to meet the needs of Superfund. In addition, the
state of Illinois has requested bids for mobile incineration
systems.
• Many fixed technologies are currently available and are used by
a number of large industries for RCRA wastes. Modifications
of these units (i.e., smaller sizes and modular construction) to
accommodate mobility probably could be accomplished in a
relatively short time (less than 6 months).
There are a number of impediments to development and com-
mercial use of mobile treatment systems. Some of these imped-
iments are:
• Shortage of reliable and comparable technical performance
information and standardized cost data
• Uncertainties in scale-up of designs from bench- or pilot-scale
• Uncertainty in the performance and treatment standards for
many pollutants
• Substantial delays and cost increases resulting from compli-
cated procedures for environmental permitting
• Difficulty in obtaining liability insurance to cover operational
risks during development and testing of various technologies
• PRP concerns about liability in the event of innovative tech-
nology failure
• Hesitation by states to use innovative technologies given the
perceived uncertain reliability of such technologies
• Tendency of concerned communities surrounding Superfund
sites to prefer remedial alternatives that remove all hazardous
substances to a management facility that is far from the site;
innovative on-site technologies may, therefore, appear less
attractive from the adjacent community's point of view.
In spite of these impediments, options are being considered
and, in some cases, used to remove them and/or create incentives
to promote development of innovative mobile technologies.
346 ALTERNATIVE TECHNOLOGIES
-------
For example, CERCLA amendments now pending may solve
the PRP concerns about liability by allowing the U.S. EPA to
indemnify those participating in cleanups. In addition, state sup-
port for mobile systems is increasing. Illinois has requested bids
for mobile incineration systems. New York currently owns a py-
rolysis (plasma arc) system and will be testing it soon at one of its
hazardous waste sites.
PLANNING CONSIDERATIONS
Mobile treatment systems can be designed and operated to
handle almost any waste type processed by permanent units. Lim-
ited experience using these systems necessitates, however, a very
close assessment of their applicability, design and operation on a
case-by-case basis.
There are many planning considerations that must be incorpo-
rated into an assessment of the viability of mobile systems for a
particular site. The direction provided in U.S. EPA guidance doc-
uments on planning remedial investigations and feasibility studies
is very useful in this assessment. Some of the more critical plan-
ning considerations are:
• Waste characteristics
• Site constraints
• Potential environmental impacts
• Costs
• Technology support requirements
Each factor will be addressed in the subsequent sections.
Waste Characteristics
It is important to identify and assess both favorable and restric-
tive characteristics of wastes with respect to each treatment sys-
tem. Examples of characteristics to consider in selecting a treat-
ment system are:
• Waste variability and requirements for treatment performance
—some technologies can handle a wide range of wastes with
consistent treatment performance while others are more sus-
ceptible to variable waste conditions.
• Non-Toxic waste components—operational problems such as
fouling and plugging of equipment can result from innocuous
components such as iron, suspended solids and naturally occur-
ring organic materials.
• Need for pretreatment—some wastes may require a more elab-
orate treatment process while others may be treated by a less
capital intensive treatment process such as fixation/solidifica-
tion.
Each mobile technology system must be reviewed to identify
the waste types that can be processed with that unit. Restrictive
waste characteristics, i.e., wastes with characteristics that may
interfere with efficient operation, and requirements for both pre-
treatment and post-treatment should also be identified.
Site Constraints
When locating equipment on the site (or immediately off the
site), one should consider many factors such as:
1 Impact on the local community
• Security of the equipment
• Existence of adequate electric utilities
• Roads for large trailer accessibility
' Water supply
' Sewer lines
* Slope stability of the land
* Soil conditions
•Flood plains
* Local zoning ordinances
Mobile treatment systems should rely as much as possible on
existing utilities in order to speed implementation and to prevent
unnecessary capital expenditures on auxiliary equipment. Site
preparation required to operate a mobile system may include:
• Access roads
• Concrete pads for equipment
• Accidental spill control and staging
• Connections to public utilities
Potential environmental impacts must also be weighed in the
equipment siting decision.
Potential Environmental Impacts
Environmental impacts are an important consideration with
regard to mobile treatment systems:
• Air pollution can be a major concern for incineration systems
and air stripping systems.
• Constituents must be identified and their transport away from
the facility must be anticipated under worst case situations
(e.g., stagnant air and thermal inversions).
• Road construction and intensive activity on-site may create
additional pollution problems such as airborne particulate
dust, surface runoff and erosion. These emissions of fugitive
dust are of particular concern if disturbed soils are contam-
inated.
• Noise generated during waste treatment or during equipment
transport may disturb nearby residents.
Every effort should be made to minimize these impacts by se-
lecting the proper location for the mobile units and by following
good engineering practices. The health and safety of the workers
as well as nearby residents must be considered, and sufficient
precautions should be incorporated into the remedial program de-
sign.
Residuals generated by the selected treatment process must be
handled in an environmentally safe manner in order to minimize
future potential environmental impacts. The concentration and
quantity of residuals must be assessed early in the selection pro-
cess to incorporate proper treatment and/or disposal into the
overall process. Extensive requirements and/or restrictions with
respect to residuals for one treatment process may make the use
of other treatment technologies more favorable.
Although the potential for negative environmental impacts
does exist, mobile treatment systems offer many beneficial en-
vironmental impacts for the remediation of Superfund sites in-
cluding:
• On-site treatment systems eliminate the need to transport
contaminated materials to off-site facilities. As a result, poten-
tial risk during transport is eliminated.
• Mobile treatment systems could reduce the implementation
time for remedial action and prevent further contamination.
• Mobile systems can treat source materials efficiently and min-
imize the overall impact due to extensive removal and activities.
Costs
The cost of implementing mobile treatment technologies is
also important in determining the preferred alternative. There are
five major cost concerns that may affect the selection of one tech-
nology over another:
• With all alternatives, capital, operating and maintenance costs
must be carefully reviewed to assess the economic impacts to
the remedial program.
• Several innovative mobile technologies have large capital equip-
ment costs. If a specific technology is applied to numerous
sites, however, the cost of the equipment can be shared by
ALTERNATIVE TECHNOLOGIES 347
-------
these projects. The end result would be savings in the Super-
fund program. Mobile treatment may, therefore, provide the
advantage of using higher cost technologies on Superfund sites.
• Many mobile units have not been used extensively at Super-
fund sites. Therefore, cost data are not yet available.
• Waste-specific conditions can greatly affect the costs of a re-
medial program, and efforts to provide detailed cost estimates
for these technologies usually must be made on a case-by-case
basis.
• Labor-intensive efforts may be required for mobile systems due
to the high variability of the waste; however, these costs can be
offset by reduced handling and disposal costs of the residuals.
Technology Support Requirements
The use of specific mobile treatment systems should include
an assessment of:
• Utilities required (e.g., electricity, water, wastewater, fuel and
cooling) for system operation
• Availability of utilities at the site and the services required for
the treatment system (e.g., laboratory and maintenance)
• Extent of training required for the operating labor force; in
general, the labor force for a mobile treatment system used at a
Superfund site will require more training because the monitor-
ing requirements for the process operation will b« more inten-
sive than for permanent treatment systems or for nonproceu
alternatives.
The reasons for the additional training are:
• Field operation of mobile treatment systems, particularly in
the initial stages, may be labor intensive
• Automatic control systems are employed less often
• The variability of the waste requires a significant monitoring
effort
CONCLUSIONS
A summary of the planning considerations for several mobile
technologies (Table 2) is included to provide a qualitative review
for comparison with other technologies. Descriptions of the waste
types, the removal/destruction capability, the residual generated,
the residual management and the relative costs are detailed for
each mobile technology. The management of residual side
streams and effluents may require additional processing steps
Tibet 2
Summary D»U on Mluile Technologic*
Primary Waste
TtCIINUlOcr
TICKHAL IREATKNT
Incineration
Rotary Kiln
liquid Injection
Fluidtied Bed/
Circulating Bed
Infrared
Pyrolysis
PI JVM Arc
Advanced Elec. Reactor
rbblle
Uilt
Status
Conrerclal
Ccmnerctal
Pilot
Pilot
Pilot
Pilot
Types
Class
0
0
0
0
0
0
Treated
Fore
S.I
L
S.I
S.L
I
S.I
Unubllltatlon/
Removal/
Oestruct Ion
Capability
Very High
Very Illgh
Very III oh
Very Illgh
Very High
Very High
Reduction of
Waste Volux
Illgh
High
High
High
Illgh
Illgh
Air Missions
or Residues
feneraled
A.L.S
A.I.S
A.l.S
A.I.S
A.I
A.L.S
•Wet O.ldatlon-
Supercritical Uater
Ondatlon
Wet Air Oildatlon
IHfltlllZATION
Pilot
Comnercla!
l.W
I
Very High
Illgh
Illgh
Moderate
A.L.J
I
Inorganics In ash/landfill
Inorganics In ash/landfill
Inorganics In ash/landfill
Inorganics In ash/landfill
Inorganics In ash/landfill
Inorganic! In uh/lanlllll
Inorganic! In treated streai
Inorganics/organIcs In
treated stream
Relative
[situated costs
Capital nu<
High
High
High
High
High
High
High
High
High
Illgh
High
Illgh
High
High
High
High
fliatlon/Solldlflcatlon
tenrnt-based
Flyash or Lime-based
Asphalt-based
RtrflVAl TF.CIMXOCIES
Connvrclal
Comnerclal
Pilot
S
S
dry S
High
High
High
tone
Hone
tone
landfill
landfill
landfill
low low
low loo
McdllB
Chen leal
Uildalion-Reductlon
Neutralisation
Precipitation
Oechlorlnatlon
Physical
Distillation
Steam Stripping
Cruse Separation
Air Stripping
Activated Carbon
Clarification
Evaporation
Soil Washing
Filtration
Ion Exchange
HcmVanu Separation
Biological Treatment
/Wrobic
Anaerobic
Mobile Unit Status
totiniTC liil • Full Seal
Pilot • Demonstration
Comcrclal
Comnerclal
Comnerclal
Comerclal
ConrcrcUl
Comnerclal
Cflnmsrc lal
Ccninerclal
Corm.-rc lal
Cannorclat
Conrarclal
Pilot
Comncrclal
Connercla)
Pilot
Conncrclal
Coflncrc 1 a 1
e/flperallonal
Scale/Operational
1.0
1.0
1
0
0
0
O.I
0
0
1
O.I
O.I
1
1
O.I
0
0
S.l.W
S.l.GW
l.GW
L.S
L.GU
S.L.GW
S. L
GW.S
GW
GW.l
L.S
S
GW.l.S
GW
GW.l
GW.l
6W.L.S
Moderate
Illgh
federate
Hlijh
High
Illgh
Moderate
High
Very Illgh
Moderate
Illgh
Moderate
Illgh
Very Illgh
Very Higli
Illgh
Illgh
W»te Class
0 • Crnanlc
1 • Inorganic
Moderate
Moderate
Illgh
Illgh
Illgh
High
Moderate
Illgh
Illgh
Moderate
Illgh
Illgh
High
Illgh
III Oil
Moderate
Moderate
Waste Fora
S •Solids/Sludge
1 • Concentrated liquid
GW • Groundwater
(low concentration)
*.S
*,S
S
US
L
I
L.S
*.L
L
l.S
l.S
l.S
l.S
L
I
l.S
l.S
QewattrlnoAandflll
DeMilerlng/landflll
Oe-alerlng/landllll
Landfill
Recycle/destruction
Recycle/destruction
landfill/destruction
Treatment of air missions
Carbon Regeneration
landfill
landfill/destruction
Washing Fluid Treatment
Oewater /landfill
Recycle/destruction
Recycle/destruction
flc water Ing/landfill/
destruction
Dewaterlng landfill
Emissions
Removal Efficiency Generated
Low MedlM
Low Medlw
low Hedlin
Hedluei High
High High
High High
Moderate Low
low low
High High
Low low
low High
Moderate Moderate
low Moderate
High Moderate
High Illgh
low low
low low
or Residues
Byproduct
Very Illgh - >Q« A • Air
Illgh -951 L • liquid, concentrated
Moderate -til S • Solid
348 ALTERNATIVE TECHNOLOGIES
-------
and increase costs. Thus, planning considerations should thor-
oughly evaluate the treatment and/or disposal of these residuals.
In summary, the transfer of treatment technologies from
RCRA wastes to CERCLA wastes into a mobile configuration
shows great promise for the cleanup of uncontrolled hazardous
wastes sites where the remedial action can be accomplished with-
in a reasonable timeframe. The application of mobile treatment
technologies will allow more capital intensive technologies to be
used for the cleanup of hazardous waste sites, sharing the costs
between several projects. The application of mobile technology
will result in a decrease in the total cost for the cleanup of each
Superfund site.
The technology transfer, however, is complicated by the un-
characteristic nature of CERCLA wastes, and the application of
these mobile technologies must be reviewed on a case-by-case
basis. The use of a mobile treatment technology at a particular
Superfund site may require extensive laboratory and/or pilot
scale treatability studies to assess the specific application to
Superfund wastes.
ALTERNATIVE TECHNOLOGIES 349
-------
Response to an Underground Fire
At an Abandoned Hazardous Waste Landfill
David G. Pyles
Scott D. Springer
Roy F. Weston, Inc.
Chicago, Illinois
Briand C. Wu, Ph.D.
U.S. Environmental Protection Agency
Chicago, Illinois
ABSTRACT
An underground landfill fire on the south side of Chicago,
Illinois, was reported to the U.S. EPA in August of 1985. The
scene of the fire was previously an industrial waste disposal facil-
ity owned by the U.S. Scrap Corporation. The facility reportedly
operated from the late 1960s through 1975 during which time in-
dustrial waste and debris were disposed on-site in pits; industrial
wastes were also burned in an incinerator.
In response to actual and potential threats to human health
posed by the fire and other side conditions, the U.S. EPA con-
ducted a removal action under authority of CERCLA. This paper
details both the efforts at extinguishing the uncontrolled under-
ground fire and at mitigating potential threats posed by the
alleged presence of chemical, shock-sensitive, radioactive and
biological wastes in an elevated railroad roadbed bordering the
site. Emphasis has been placed on the U.S. EPA's utilization of
advanced technology in monitoring and mitigating site con-
ditions.
INTRODUCTION
The U.S. Scrap Corporation (U.S. Scrap) was an industrial
waste disposal facility located on the south side of Chicago,
Illinois (Fig. 1). The abandoned site was brought to the atten-
tion of the U.S. EPA on Aug. 16, 1985, when an official em-
ployee with the Chicago Metropolitan Sanitary District (MSD) re-
ported dense smoke emanating from several areas of the haz-
ardous waste landfill. In addition to the potential threats posed
by the off-site migration of toxic gases, U.S. EPA and Technical
Assistance Team personnel identified a second serious potential
hazard posed by the site; namely, the alleged presence of shock-
sensitive and toxic waste within the landfill. The remainder of this
paper summarizes the site's physical properties and operating
history and the U.S. EPA's response to the two major hazards
posed by site conditions.
SITE DESCRIPTION AND OPERATING
HISTORY
The U.S. Scrap site measured approximately 270 by 1,600 ft
(Fig. 2). The site was bounded on the west by a railroad embank-
ment, on the south and east by a sewage treatment facility oper-
ated by the MSD and on the north by an industrial area. Residen-
tial areas were located 1,500, 3,000 and 4,000 ft east, north and
south of the site, respectively. Notable physical features on the
site included an access road leading to the southern end of the
property, a loading area and industrial incinerator near the center
of the site, and sludge pits and eight concrete silos along the site's
eastern edge.
Figure 1
Site Location Map, U.S. Scrap, Chicago, Illinois
350 ALTERNATIVE TECHNOLOGIES
-------
Garvey
Grains
Property
Slle Access Road
ine | Lagoon 4
'Property Li.
Figure 2
Site Map U.S. Scrap Landfill, Chicago, Illinois
Figure 3
Location of Regional Air Monitoring Stations
While the exact dates of operation are not known, it has been
reported that this drum reclamation facility began accepting waste
in the late 1960s and was closed by 1975. Wastes from reclaimable
drums were emptied into pits excavated on-site while other
drums, whose condition was such that recovery was not feasible,
were buried within the same pits. In addition to these recovery
and disposal practices, the company also allegedly operated under
the guise of an incineration facility.
During interviews with past U.S. Scrap employees, it was
alleged that past disposal practices included the burial of drums
containing pesticides, shock-sensitive wastes and hospital wastes.
The hospital wastes were allegedly in the form of lab packs con-
taining radiated biological research wastes, blood specimens
and body parts. Reportedly, these drums were implanted into the
railroad embankment along the western border of the site; the
common procedure used was to excavate a small cavity into the
embankment, place three or four drums into the opening and
subsequently cover the drums with the excavated fill.
A hospital that was contacted for the purpose of gathering
additional information confirmed that it had sent several types of
waste to the U.S. Scrap site for disposal. It was estimated that
ether and radioactive wastes would be very abundant within the
lab pack materials. The origin and actual volume of other wastes
that reportedly were buried within the embankment were un-
known.
Prior to the CERCLA-funded action described in this paper,
there had been limited attempts at securing a comprehensive
cleanup of the site. There was, however, a partial removal of on-
site waste under an agreement between the responsible party and
federal, state and local agencies. This action resulted in the re-
moval of 100 drums of liquid hazardous waste stored within the
silos and an estimated 10,000 gal of sludge within drainage swales.
U.S. EPA INVESTIGATIVE AND
MITIGATIVE ACTIONS
Proper response to any emergency situation involving haz-
ardous materials involves the following three key tasks: (1) iden-
tification of the materials involved, their distribution and their in-
herent threats as determined by their specific chemical and physi-
cal characteristics; (2) assessment of the threats posed to the gen-
eral public, the environment and the responding personnel; and
(3) mitigation of these threats after prioritizing each and evaluat-
ing the feasibility and effectiveness of alternative actions. It was
within this framework that the U.S. EPA conducted a compre-
hensive investigation and timely removal action at the U.S. Scrap
Landfill. As described in the following discussion, priority first
was given to the underground fire as it posed the most immed-
iate potential threat to the health and well being of residents and
workers in the vicinity.
Response to the Underground Fire
The primary objectives of investigative efforts upon mobiliza-
ALTERNATIVE TECHNOLOGIES 351
-------
tion to the site on Aug. 11, 1985, were to characterize the air
emissions originating from the site and to document the location
and nature of the underground fire. Within hours after the initial
response, the gases emanating from fissures or "vents" created
by subsidence were partially characterized, and the primary burn
areas within the fill were identified through field observations.
Initial air monitoring efforts revealed the presence of compounds
such as hydrogen cyanide, hydrogen chloride, hydrogen sulfide,
benzene and acetone. Some of the compounds are known to be
acutely toxic at low levels, while others are classified as carcino-
genic.
Subsequent to the discovery of these compounds, the U.S.
EPA: (1) directed the cleanup contractor to begin applying clay
caps on all venting areas; (2) expanded the air monitoring and
sampling program to document air quality; and (3) initiated addi-
tional efforts to define the extent of the underground fire. The
fire had, at this point, progressed to the stage where flames at the
vents were clearly visible in brightest daylight.
Air Monitoring
The air monitoring performed during this phase of the response
further characterized the off-gases in order to protect personnel
conducting on-site investigations and mitigative operations; air
quality in adjacent residential areas also was determined in order
to ensure the protection of public health.
Several air monitoring techniques were employed in support of
on-site activities at the U.S. Scrap site. Real-time monitoring in-
strumentation utilized included combustible gas indicators,
organic vapor analyzers (OVA), photoionization detectors (PID),
permissible toxic gas indicators and colorimetric detection tubes.
The OVAs and PIDs detected organic gases at concentrations ap-
proaching 200 ppm in areas near the vents. Of the four types of
permissible toxic gas indicators used (i.e., phosgene, hydrogen
cyanide, hydrogen sulfide and hydrogen chloride), all detected
concentrations above their respective alarm levels with the excep-
tion of phosgene. Colorimetric tube results correlated well in the
identification of these compounds.
The detection of toxic gases in the vent gas and the knowl-
edge that large amounts of solvents and other volatile materials
were burned at the site suggested that off-site releases of contam-
inants may have been occurring. Therefore, an eight-station off-
site monitoring program was concurrently operated in conjunc-
tion with the on-site program. The eight stations established in
neighborhoods surrounding the site (Fig. 3) were attended every
8 hr and monitored for airborne contaminants. This monitoring,
maintained throughout the duration of the fire, did not detect
off-site releases of those compounds identified through on-site
air sampling.
The precise delineation of the aerial extent of the underground
fire was obtained through the use of two innovative technolo-
gies: infra-red photometry and thermocouple temperature
probes. The photometry was conducted at night; an infra-red
camera was taken aloft by a light, fixed-wing air craft. The air
craft would perform low altitude (minimum of 1,000 ft) over
flights of the U.S. Scrap site while the infra-red images were re-
corded on video equipment allowing for later viewing and inter-
pretation. For purposes of establishing proper scale and accurate
mapping of burn areas, reflectors (in this case two by two foot
aluminum foil) were placed in a 50- by 50-ft grid pattern over the
entire site (Fig. 4). The initial over flights revealed the presence
of two major burn areas (Fig. 5). This information proved in-
valuable as the burn areas were shown to extend beyond the vent-
ing areas that were initially capped to reduce contaminant emis-
sions.
Burn Area Delineation
In conjunction with the infra-red photometry, the U.S. EPA
conducted subsurface temperature monitoring through the use of
thermocouples implanted approximately 3 to 4 ft below the
ground surface (Fig. 5). In addition to monitoring the intensity
and horizontal migration of the fire, the temperature probe data
were correlated with the infra-red images. This correlation
allowed rough approximations of the subsurface temperature
without requiring the relocation of probes.
The data collected by the U.S. EPA through its investigative
efforts documented several substantial threats to human health.
The landfill fire was releasing volatile organic compounds and
various toxic gases resulting in a direct contact (i.e., inhalation)
threat. Left unattended, the fire could have intensified and emit-
ted higher volumes and concentrations of those compounds, thus
increasing the potential for air contaminant migration into adja-
cent residential areas. This threat, in addition to the threat of
explosion of subsurface wastes, demanded that the underground
fire be totally extinguished. Toward this end, several methods for
extinguishing the fires at the U.S. Scrap site were identified and
evaluated.
Remedial Action
Considerable discussion between all involved responding per-
sonnel generated six options to extinguish the fires. These options
were:
• Continued remote monitoring with additional capping of each
burn area
• Application of large volumes of water over burn areas with
passive infiltration
• Subsurface injection of cryogenic inert gases into burn areas
• Artificial raising of the perched water table under burning
masses
• Construction of a surface pond over the burning masses
• Exhumation of burning material and extinguishment above
ground
After intensive evaluation, taking into account public health,
feasibility, potential for positive results and cost, the capping op-
tion was selected. The cap required approximately 1,600 yd3 of
clay and was put in place within 2 days.
Figure 4
Site Control Grid, U.S. Scrap Landfill
Infra-red overflights and thermal probes monitoring indicated
the northern burn area to be burning in a southerly direction,
out from under the capped area. Therefore, a second applica-
tion of clay was required. The cap proved to be highly effective
and eliminated a majority of the on-site air emissions. The cap
was periodically watered to inhibit the cap from cracking. Once
the capping technique appeared to be effectively controlling and
extinguishing the burn areas, permanent temperature probes were
installed to enhance the definition of the thermal anomalies.
To add further definition of subsurface gas composition, a
soil gas survey was conducted by the U.S. EPA Environmental
Response Team (ERT). The survey identified the presence of a
complex array of organic compounds, including benzene,
toluene, ethyl benzene, xylene and trichloroethylene. This survey
correlated closely with the data from several soil samples that had
352 ALTERNATIVE TECHNOLOGIES
-------
Garvey
Grains
Property
Legend
A Subsurface Temperature
Monitoring Point
Lagoon 4
Figure 5
Underground Fire Location Map, U.S. Scrap Landfill, Chicago, Illinois
been obtained from the site.
Within 3 weeks, the temperatures decreased gradually to
ambient conditions. Once the fire was completely extinguished,
the second serious potential hazard posed by the site was
addressed.
RESPONSE TO WASTE IN THE
RAILROAD EMBANKMENT
Consistent with the aforementioned emergency response frame-
work, the U.S. EPA first determined the types of waste and their
distribution within the embankment, second assessed the threats
posed by these materials within the physical setting at the U.S.
Scrap site and third performed a removal action to eliminate and/
or mitigate the respective health and environmental hazards. The
remainder of this section discusses the various actions under-
taken within each stage of the response.
The task of characterizing the nature and location of buried
waste, prior to actual exhumation, required considerable effort.
As mentioned previously, the U.S. EPA obtained information on
the types and quantities of waste within the embankment from
the reports of waste generators suspected of having sent waste to
the site and from interviews with former U.S. Scrap employees.
During these interviews, it was alleged that past disposal prac-
tices included the burial of drums containing pesticides, shock-
sensitive wastes and hospital wastes (the latter were in the form of
lab packs containing radiated biological research wastes, blood
specimens and body parts). Visual scans of the embankment
tended to confirm the alleged burial practices, as several drums
were protruding from the ground. To further corroborate the
allegations, and in an attempt to delineate the sections of the em-
bankment used for burial purposes, a geophysical survey was
conducted.
Geophysical Survey
The survey was conducted within a sampling grid along a 1,500-
ft length of the railroad embankment using both an EM 31 elec-
tromagnetic conductivity meter and a SCINTREX MF-2 flux
gate magnetometer. During the course of the survey, documen-
tation of surface debris that may have affected instrument read-
ings was maintained. The raw data were entered into a Tech-
tronix data processing system that generated contours of the raw
data, first partial derivative with respect to the X-axis and first
partial derivative with respect to the Y-axis. The results of each
survey were correlated and the anomalies were summarized in
graphic form (Fig. 6).
The extent of the anomalies suggested that virtually the entire
length of the embankment exhibited a high potential for the
occurrence of buried ferromagnetic material. Although the survey
could not distinguish buried drums from other ferromagnetic ma-
terial, it did tend to verify allegations made by former U.S. Scrap
employees regarding the burial operations along the embank-
ment.
Based upon the rather consistent information obtained from
both waste generators and former employees of the operation, the
data generated from the geophysical survey and data from lim-
ited sampling efforts, the U.S. EPA determined that the waste
within the embankment posed a significant threat to public health
and the environment. The primary threats cited were fire and ex-
plosion and exposure to hazardous substances by nearby popula-
tions.
Removal Planning
Subsequent to the determination that the site continued to pose
a significant threat, the U.S. EPA began to develop a detailed re-
moval plan. Such a plan was deemed critical as removal of the
alleged waste presented complex safety and logistical problems.
The resulting plan identified three work phases: (1) preparation
of the site; (2) excavation of the drums; and (3) performance
of followup studies.
g e
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Figure 6
Correlation Between Exposed Drum Occurrence and Geophysical Results
Site preparation activities were extensive and generally con-
sisted of the development of safety and contingency plans, devel-
opment of materials handling procedure and construction and/or
set-up of staging and work zones. The site safety plans for both
technical and cleanup personnel were developed based upon con-
servative projections of the types and quantities of materials that
were to be unearthed.
ALTERNATIVE TECHNOLOGIES 353
-------
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Figure 7
Materials Handling Decision Diagram, U.S. Scrap Corp.,
Chicago, Illinois
Figure 9
U.S. Scrap Landfill, Chicago, Illinois, Transect Air Sampling Technique
Contingency planning resulted in several pre-excavation actions
including:
• Construction of two 10,000 gal pools to aid in extinguishing
potential fires during drum handling activities
• Stockpiling of sand to handle potentially exposed air-reactive
waste
• Establishment of a communicative system with the Chicago
and Western Indiana Railroad Company enabling the coor-
dination of site activities and train movements atop the em-
bankment
Because of the variety and hazards associated with the buried
wastes, a materials handling protocol was established. The result-
SitaAccaiifVMd'
Figures
Site Layout Map, U.S. Scrap Landfill, Chicago, Illinois
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Figure 10
Correlation Between Anomalies and Survey Techniques
ing decision diagram (Fig. 7) was developed and incorporated
into the excavation operating plan.
Proper site preparation also required the construction of sev-
eral staging and work zones (Fig. 8). Two staging areas were
established at the southern end of the site for radioactive and
nonradioactive wastes, respectively. Also constructed were
detonation bunkers for ignition of shock-sensitive waste and a
portable building for lab-pack separation.
354 ALTERNATIVE TECHNOLOGIES
-------
Removal Action
The second phase of the removal action entailed the excava-
tion of the drums and the initiation of a comprehensive air moni-
toring program. Immediately prior to drum removal, personnel
from the U.S. EPA's Technical Support Division provided guid-
ance and equipment for radioactive material identification and
performed a radiation survey of the entire embankment. The sur-
vey revealed no reading above the ambient range. Fire breaks
then were excavated every 300 ft along the embankment to min-
imize possible chain reaction fires and/or explosions. During a
5-day period in mid-October, 1985, 77 drums containing mercap-
tans, paint residues and resins were exhumed. The expected
shock-sensitive, radioactive and acutely toxic materials were not
exposed.
Throughout the period of drum exhumation, the U.S. EPA
performed both on- and off-site air monitoring. In addition to
the standard array of real-time monitoring instruments, portable
air sampling pumps and high-volume air samplers were used to
obtain data on organic and inorganic airborne contaminant con-
centrations, respectively. The portable pumps were equipped
with activated charcoal collection tubes and were configured ac-
cording to the transect technique (Fig. 9). A less elaborate config-
uration of high-volume samplers was maintained. Analysis for
both organic and inorganic constituents revealed no constituents
significantly above ambient concentrations.
Final Monitoring
The third phase of the response included post-excavation ac-
tivities such as conducting a second geophysical survey of the em-
bankment and further sampling efforts. The second geophysical
survey was performed in early November, 1985. The primary
objective was to determine if any ferromagnetic anomalies re-
mained within the embankment. The methodology and equip-
ment used were the same as the first survey with one exception:
due to the installation of a 6-ft chain-link fence on the embank-
ment crest, the grid system was shifted 15 ft to the east. Fig. 10
displays the occurrence of the geophysical anomalies, the ma-
jority of which were suspected to be caused by surficial metal
near the embankment and the recently installed fence. The re-
sults, therefore, suggested that the excavation successfully re-
moved all drums within the railroad embankment.
CONCLUSION
The response to the underground fire and buried waste at the
U.S. Scrap site incorporated the use of several advanced tech-
nologies. The technologies were employed in rapid fashion and
enhanced the U.S. EPA's ability to: define and monitor site con-
ditions; identify mitigation alternatives; and minimize both safety
risks for on-site personnel and health threats posed to the gen-
eral public.
ALTERNATIVE TECHNOLOGIES 355
-------
Superfund Innovative Technology
Evaluation Program
Ronald D. Hill
U.S. Environmental Protection Agency
Hazardous Waste Engineering Research Laboratory
Cincinnati, Ohio
Donald C. White, P.E.
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Washington, D.C.
Robert N. Ogg, P.E.
CH2M HILL
Reston, Virginia
ABSTRACT
The U.S. EPA has initiated the Superfund Innovative Tech-
nology Evaluation (SITE) program to allow it to participate with
the private sector in an effort to enhance the use of innovative
cleanup technologies in the Superfund program. The SITE pro-
gram is intended to enhance the development and demonstration
of promising innovative technologies and thereby assist in estab-
lishing their commercial availability. The program has been de-
scribed in the SITE Strategy and Program Plan published by the
U.S. EPA.
There are four parts of the SITE program including Super-
fund regulatory and policy analyses, research and development
activities, an analysis of the potential demand for specific demon-
strated technologies and full-scale Held demonstrations of
promising technologies at Superfund sites. The SITE program is a
joint effort between the Office of Solid Waste and Emergency
Response and the Office of Research and Development.
INTRODUCTION
Concern exists over the extensive use of land-based contain-
ment technologies to mitigate the problems posed by Superfund
sites. This concern has been expressed by the public, the Office of
Technology Assessment, U.S. EPA's Science Advisory Board and
Congress. The U.S. EPA recognizes this concern and has devel-
oped the Superfund Innovative Technology Evaluation program
(SITE) to accelerate the development, demonstration, and use of
innovative technologies at Superfund sites. The program is jointly
sponsored by the U.S. EPA's Office of Solid Waste and Emer-
gency Response and the Office of Research and Development.
The primary purpose of the SITE program is to enhance the
development and demonstration of innovative technologies and
thereby establish their commercial availability for use at Super-
fund sites. To accomplish that purpose, the program has four
goals:
• To identify and where possible to remove impediments to the
development and commercial use of alternative technologies
• To conduct a demonstration program of the most promising
innovative technologies to establish reliable performance and
cost information for use in site-specific decisions under Super-
fund
• To develop procedures and policies to encourage the develop-
ment and selection of appropriate innovative and alternative
technologies in lieu of land-based containment technologies at
Superfund sites
• To structure a research and development program to nurture
emerging technologies
This paper will discuss each of the four parts of the SITE pro-
gram in further detail and provide a summary of progress in im-
plementing the program. SITE includes a technology transfer,
community relations and a communications strategy to assist in
ensuring that information developed is made available to appro-
priate audiences. In addition, the demonstration of promising
innovative technologies is the present focus of the SITE program
and therefore that effort will be discussed in depth.
BACKGROUND
Under the current Superfund program, the predominant
method of remedying a site is to move the wastes to regulated
land disposal sites or to contain the wastes on the Superfund
site itself. Neither approach is a true remedy; the wastes are
neither treated nor destroyed. The contained sites require con-
tinued maintenance to ensure that an unacceptable level of con-
tamination does not escape from the system to the environment.
In addition, containment systems do not last forever and must be
replaced periodically. This places a long-term burden on agencies
responsible for ensuring the site's integrity.
The U.S. EPA believes that land-based containment technol-
ogies are not appropriate for the Superfund program. Consis-
tent with the intent of the National Contingency Plan, the U.S.
EPA prefers to utilize technologies that destroy, immobilize
and/or treat contaminants instead of merely containing them.
However, the legislative requirement to take costs into account
when selecting a remedy and the practical limitations of existing
technologies mean that containment systems will not be elim-
inated altogether.
The U.S. EPA has agreed that there needs to be a comprehen-
sive program to assist industry in developing long-term perma-
nent solutions for Superfund cleanups. It also appears that the
legislation reauthorizing Superfund will establish an RD&D pro-
gram for innovative and alternative technologies. In response to
the evidence in favor of such a program, ORD and OSWER
have developed and are implementing the SITE program to en-
hance the commercial availability of innovative technologies for
use at Superfund sites.
The terms "alternative technology" and "innovative technol-
ogy" are widely used central concepts in the SITE program. An
alternative technology is any unit operation or train of unit oper-
ations that permanently alters the composition of hazardous
356 ALTERNATIVE TECHNOLOGIES
-------
wastes through chemical, biological or physical means to signif-
icantly reduce the toxicity, mobility and/or volume of the haz-
ardous waste or contaminated material being treated. In essence,
alternative technologies are any treatment technologies that are
alternatives to land disposal. Alternative technologies may be
"available," "innovative" or "emerging" (Fig. 1).
Available alternative technologies, such as several forms of in-
cineration, are fully proven and available for routine commer-
cial or private use. Innovative technologies include any fully
developed technology for which insufficient cost or performance
data exists to allow its routine use. Innovative technologies re-
quire full-scale field testing. Emerging alternative technologies
are ones for which research has not successfully passed labora-
tory and pilot scale testing.
The four parts of the SITE program address each type of
alternative technology noted above and, as noted earlier, are in-
tended to foster the use of innovative alternative technologies at
Superfund sites.
IMPEDIMENTS TO THE USE OF
INNOVATIVE TECHNOLOGIES
There are a number of impediments to the acceptance and use
of innovative technologies for the treatment of wastes at Super-
fund sites. Under the SITE program, they are categorized as in-
formational, regulatory and institutional impediments.
CONCEPT
PROVEN
TECHNOLOGY
DEVELOPED
ALTERNATIVE
TECHNOLOGY
DEMONSTRATION PROVEN AND
DATA AVAILABLE
LAB SCALE
DEMONSTRATION
GUIDANCE
J
'EMERGING* 1
INNOVATIVE
AVAILABLE
Figure 1
Alternative Technologies in Relation to the
Technology Development Process
Informational impediments are generally those associated with
the fact that if insufficient information exists concerning the cost
and performance of a technology, potential users will be reluc-
tant to invest in it. The SITE strategy assumes that there is a
shortage of reliable and comparable technical performance in-
formation and standardized cost data for innovative technolo-
gies and that this deficiency is inhibiting the acceptance and use
of such technologies. A major objective of the demonstration
program is to develop data to overcome this informational im-
pediment.
Another identified informational impediment is uncertainty
surrounding marketing. A market must be defined so developers
can decide whether and how much venture capital will be worth
risking to pursue the development of innovative technologies.
Relevant market related issues include definition and standardiza-
tion of performance and treatment standards and the long-term
outlook for the nation's commitment to Superfund site clean-
ups. The SITE program will help overcome these barriers through
a technology transfer effort, regulatory and policy analyses (in-
cluding the applications analysis described later in this paper)
and general information transfer.
Regulatory impediments to the use of innovative technologies
are more generally recognized. The most discussed impediment
is the array of permitting requirements, including the delisting of
residual wastes that face a potential developer when attempting to
bring a technology from the laboratory to full-scale demonstra-
tion and into use at a site. Efforts under the SITE program will
focus on assisting existing and on-going work groups, task forces
and policy groups within the U.S. EPA which have been formed
to address regulatory issues. An example of such ongoing groups
is the Mobile Treatment Task Force which is investigating imped-
iments and issues concerning the use of mobile-treatment units at
Superfund sites. The purpose of such work groups is to solve
identified problems over which the U.S. EPA has control. Addi-
tional impediments exist which are outside the control of the U.S.
EPA.
There are also institutional impediments to commercialization
of innovative technologies. Institutional impediments refer to in-
hibiting factors that are outside the regulatory arena which may
affect private parties, communities surrounding Superfund sites
and governmental entities. An example of an institutional im-
pediment for a private party is the potential lack of sufficient
liability insurance for a developer to risk pursuing his technology.
A governmental impediment is the use of a definition of cost-
effectiveness which encourages the selection of traditional con-
tainment systems even though an analysis of long-term costs
would result in the opposite conclusion.
Communities near Superfund sites generally prefer solutions
which remove the wastes from their area. Therefore an innova-
tive technology treating wastes on-site may not be well received.
The SITE program does not envision a specific study to address
identified areas of impediments. Instead, the program will
address the problems both through working with established
Agency mechanisms to modify policies, guidance and regula-
tions, as necessary, and through generating and disseminating
information which may be used by the existing Work Groups,
Task Forces, private sector and public.
DEMONSTRATION PROGRAM
During development of the SITE strategy, the Agency's efforts
were reviewed and commented upon by a number of experts
outside of the U.S. EPA. These individual experts have collec-
tively been referred to as the SITE Strategy Review Group. One
of the major points made by that group in its review was that
acceptance of a new technology is driven by and dependent upon
the level of confidence in the technology by decision-makers
and the public. The most important factor in gaining the neces-
sary level of confidence is the availability of pilot and full scale
demonstration data indicating that the technology can be con-
sidered both operational and reliable. Therefore, to meet the
objective of the SITE strategy of moving developed technologies
into routine use, the program includes a significant effort directed
to full-scale field testing of promising innovative technologies.
The goal of this Demonstration program is to allow the U.S.
EPA to evaluate innovative technologies in realistic test con-
ditions so that reliable and comparable cost and performance
data is developed and made available. The U.S. EPA's crucial
role in the demonstration program is to ensure credibility of the
results by defining the testing protocols, test procedures, analyti-
cal protocols and methodologies and by performing the quality
assurance and quality control function so that the resulting data
from the demonstrations can be consistently and accurately in-
terpreted. In addition, the tests to be conducted are to simulate
actual conditions as much as possible and are to be performed
at full-scale. The end result is to provide performance, cost-effec-
tiveness and reliability data so that potential users have suffic-
ient information to make sound judgments as to the applicability
of a given technology and how it compares to other promising
technologies.
Consistent with the focus of SITE to accelerate the accep-
tance and use of innovative technologies, the demonstration pro-
gram will select technologies that have been fully developed and
ALTERNATIVE TECHNOLOGIES 357
-------
require only the collection of cost-effectiveness and performance
data necessary to determine the credibility of the technique.
Alternative technologies which are currently considered available
and therefore not innovative (e.g., some forms of incineration)
will not be considered for the demonstration program. The focus
pf the demonstration programs will be technologies that meet one
or more of the following criteria:
• Provide a permanent solution, i.e., destroy the contaminant or
significantly reduce the toxicity, mobility, volume or com-
bination thereof
• Can be utilized on-site as opposed to requiring costly transport
off-site
Are applicable to a variety of sites and wastes
Address critical problems that presently have no solution
Potentially have significantly lower costs than current methods
Provide significantly better performance than current methods
Produce manageable emissions, effluents and/or residues from
environmental, cost and health viewpoints
• Are easy and safe to operate
The scale of the demonstrations will vary, but generally only
commercial scale units will participate. Any demonstration must
be at a sufficient scale to ensure that results are credible to users
regardless of future scale-up requirements. Likewise, the program
will emphasize performing demonstrations at actual Superfund
sites to further add to the credibility of results. While all sites will
be considered, the priority will be given first to federal-led Super-
fund remedial and removal sites, then to other state-led and fed-
eral facility sites and last to privately owned sites. It also may be
possible to conduct demonstrations at ORD test and evaluation
facilities if necessary.
The financial relationships between the U.S. EPA and the
developer in conducting the demonstrations are somewhat de-
pendent on the final terms of the Superfund reauthorization
bill. The bill is expected to provide specific funds to conduct the
demonstration program. It is the U.S. EPA's intent that the U.S.
EPA and the developer jointly fund the demonstration program.
The developer will be responsible for equipment mobilization and
demobilization as well as maintenance and operation during the
demonstration. The U.S. EPA will fund its costs associated with
preparing protocols and procedures, collecting performance and
cost data during the demonstration and issuing a report. The
U.S. EPA is also considering the potential of funding site prepa-
ration activities such as access roads, utility connections, founda-
tions, etc. In addition, the SITE program will be implementing a
technology transfer and communications strategy on the program
as a whole to disseminate the findings. The U.S. EPA does not in-
tend to reimburse the developer for costs associated with the
demonstration unless there is no private source of funds avail-
able and the technology is of interest to the U.S. EPA.
Demonstrations will occur under two separate but parallel
efforts. The SITE strategy contains a formal process of annual
solicitations and selections. In addition, demonstrations will be
incorporated into on-going Superfund projects. The two com-
bined efforts will assure that demonstrations are conducted (and
subsequent cost and performance data developed) as quickly as
possible and that a balanced and fair program for all interested
developers is initiated.
SITE DEMONSTRATION PROGRAM
The solicitation/selection process developed for the SITE pro-
gram is depicted in Fig. 2. While the process is obviously compli-
cated, it is designed to ensure that available technologies are iden-
tified and screened, that those with greatest potential are selected
and that all developers have equal access to the program. The
process will be administered by a steering committee comprised of
individuals from ORD's Office of Environmental Engineering
and Technology (OEET) and OSWER's Office of Emergency
and Remedial Response (OERR).
The process depicted in Fig. 2 includes development of an
annual program plan for demonstrations which is comprised of a
solicitation of technologies, selection of technologies and a deter-
mination of the priority of selected demonstrations. This annual
plan will be published and submitted for public comment. Dur-
ing implementation of the annual plan, site specific demonstra-
tions will be planned, conducted and reported upon. While the
plan will be established annually, any individual demonstration
may last longer than 1 year. Throughout the development of the
annual plan and implementation of the individual demonstra-
tions, the U.S. EPA will implement a communications strategy
to keep interested parties informed of the program and individual
site community relations plans to allow the communities in the
vicinity of the demonstrations to comment upon and participate,
as appropriate.
Figure 2
Demonstration Program Structure
The process for development of the annual plan involves four
primary steps: (1) solicitation of technologies, (2) selection of
technologies, (3) selection of demonstrations and (4) public re-
view and comment. The U.S. EPA intends to solicit candidates
through advertisements in the Commerce Business Daily and
through less formal means such as the publication of this paper.
To be eligible to participate in the demonstration program, how-
ever, a developer must respond to the Request for Proposal
358 ALTERNATIVE TECHNOLOGIES
-------
advertised in the Commerce Business Daily. The proposals then
will be formally evaluated based upon: (1) applicability to Super-
fund (i.e., the eight criteria described above), (2) readiness of the
technology and the developer to conduct a demonstration and
(3) capabilities of the developer.
As the list of eligible technologies is selected, a process to de-
termine the available sites and, therefore, the demonstrations to
be conducted also will be completed. Since it is preferable to con-
duct demonstrations at actual Superfund sites, the U.S. EPA
must actively screen the locations and match them with the prom-
ising technologies. Consideration will be given to the wastes and
media of concern to the Superfund program to ensure that
selected demonstrations are directed to recognized problems. Site
selection will consider a variety of factors including potential
public acceptance, urgency of the cleanup, PRP involvement,
U.S. EPA Regions and/or state agency involvement, status of
cleanup efforts at the site and its practicality for use as demon-
stration site. Selection of the final list of proposed demonstra-
tions will consider the effectiveness of the technology, costs asso-
ciated with the technology and the risks posed by the technology
as compared to conventional technologies. A draft of the annual
plan will be published to allow all interested parties to review and
comment upon it. After public review and comment, the annual
plan will be modified as necessary and then published in final
form, and individual site demonstrations will be implemented.
Implementing the site-specific demonstrations after the annual
plan is developed will involve several steps normally involved in
establishing such a program. Negotiations with the applicant will
occur to determine the financial arrangements and the division of
responsibilities between the U.S. EPA and the developer. Site-
specific demonstration test plans will be prepared to establish all
relevant test conditions such as equipment operating parameters,
sampling and analytical protocols, reporting responsibilities and
procedures and community and public relations procedures. A
community relations program will be implemented during the life
of the demonstration including release of the final report.
Once the actual on-site activities are completed, it will be the
U.S. EPA's responsibility to prepare a report on the results of the
demonstration.
Final demonstration reports will include information such as
performance and design parameters, waste characteristics,
destruction and removal efficiencies, process residues and wastes,
O&M requirements, operational safety considerations, mass
flow/energy balances, mobilization and demobilization proced-
ures, instrumentation and control processes and QA/QC re-
quirements. In addition, costs associated with capital, opera-
tions, maintenance, unscheduled maintenance, disposal of resi-
dues, QA/QC and administration will be reported. If possible,
time requirements for design, permitting, manufacture and
mobilization will be determined and included in the report. The
SITE technology transfer strategy will be developed and imple-
mented to disseminate the test results.
RI/FS DEMONSTRATION PROGRAM
As noted above, there will be an on-going program parallel to
the SITE demonstration program just described, which allows
the U.S. EPA to respond to opportunities and accelerate the eval-
uation of technologies. To select the appropriate remedy for a
Superfund site, the U.S. EPA performs a Remedial Investiga-
tion and Feasibility Study (RI/FS). The RI/FS is conducted to
determine the nature and extent of contamination at a site and,
therefore, the specific problems which must be addressed. The
RI/FS also evaluates the appropriateness of available technol-
ogies to remedy the site. Under the NCP, the Agency may con-
duct pilot tests and treatability studies as part of an RI/FS. Given
the U.S. EPA's desire to utilize alternative and innovative tech-
nologies, there likely will be occasions where an RI/FS will in-
clude the testing of a technology to determine its potential applic-
ability at a specific site.
To ensure consistency and comparability of data on innova-
tive technologies, the U.S. EPA intends to conduct technology
evaluations scheduled for tests as part of RI/FSs in a fashion
similar to the SITE demonstration program. These evaluations
will provide information on the technologies with a broader
applicability than likely would occur under a site specific RI/FS
demonstration.
In addition, the U.S. EPA may evaluate technologies during
the design phase of a remedial project or during a removal action
at a site, if appropriate. A test under the design phase of a project
or a removal action may occur to ensure the performance of a
technology and allow adjustments to its final design to make it
applicable to the specific site. Where appropriate, a SITE demon-
stration type test will be conducted at this stage of the Superfund
project as is contemplated for the RI/FS.
APPLICATION ANALYSIS AND
POLICY REQUIREMENTS
Successful demonstration of a technology will not guarantee
by itself that a technology will in fact be adopted for full-scale
use at Superfund sites. In addition to the analysis of impediments
and the demonstration programs described earlier, the SITE pro-
gram includes an analysis of the investment potential and long-
term demand for a technology. ,
The need for an analysis of investment potential and demand
stems from the fact that successful technologies for use in the
Superfund program will have to be available at a reasonable cost.
The determination of what constitutes a reasonable cost is in part
dependent upon the demand for the technology as well as the way
in which costs are calculated. If a given technology is used at
many sites, it is anticipated that its overall cost will be less than
if it is used at few sites. Since the U.S. EPA manages the Super-
fund program, its actions largely determine the ultimate demand
(i.e., the number of available sites) for a technology.
SITE, therefore, has included an analysis of the potential de-
mand for a given technology in its program to assist developers
in planning for commercialization of their technology. The analy-
sis is not intended to replace the normal market analyses per-
formed by the private sector, but rather will provide informa-
tion to help improve the accuracy of such analyses as well, as assist
the U.S^ EPA in long-term program planning. The effort pri-
marily will be directed to determine how many sites can use a
given technology. This may involve additional tests using surro-
gate wastes at a test and evaluation facility.
DEVELOPMENT PROGRAM
While much of the SITE program necessarily is focused on
technologies that are ready for demonstrations to accelerate their
acceptance into routine commercial use, it is recognized that there
may be technologies in a lesser state of development which de-
serve attention. Therefore, the SITE program includes a devel-
opment program to assist the development of technologies from
the laboratory and pilot-scale phases to the demonstration phase.
This work usually should be performed by the private sector.
However, where attractive technologies have not generated suffic-
ient private sector interest, the U.S. EPA may choose to assist
their development.
The development program is similar to the demonstration pro-
gram. The U.S. EPA will monitor non-federal research and devel-
opment activities to identify promising technologies. There will be
ALTERNATIVE TECHNOLOGIES 359
-------
routine solicitations to allow developers to propose a program of
U.S. EPA assistance to develop their technologies. The U.S. EPA
intends to focus on emerging alternative technologies that deal
with recycling, separation, detoxification, destruction and stabil-
ization of hazardous constituents. The selection of technologies
for U.S. EPA support will be based on the same criteria as the
selection process under the demonstration program plus con-
sideration of the capability of the developer to conduct the work
and the costs to be borne by the U.S. EPA.
The program also may involve extensive use of U.S. EPA in-
house capabilities. The Agency has several test and evaluation
facilities which may be appropriate to further research and
develop specific technologies. If the demand for such facilities
grows, the U.S. EPA may improve or modify Us facilities or some
private sector facilities may be developed to further enhance re-
search of alternative technologies. In general, however, this pro-
gram is intended to be incorporated into the U.S. EPA's long-
term Research and Development programs and become a perma-
nent part of the Agency's hazardous waste programs.
CONCLUSIONS
The U.S. EPA has initiated a major new program to further the
acceptance and use of alternative and innovative treatment tech-
nologies at Superfund sites. The program is titled the Superfund
Innovative Technology Evaluation (SITE) program and will be
jointly sponsored by the Office of Research and Development
and the Office of Solid Waste and Emergency Response. The pro-
gram is in response to the identified need to utilize treatment
technologies that actually treat or detoxify or immobilize or de-
stroy hazardous wastes rather than the containment technologies
frequently used in the past.
The SITE program is comprehensive in that it consists of four
major parts: (1) a program to identify and address impediments
to the use of innovative technologies at Superfund sites, (2) a pro-
gram to demonstrate promising technologies to develop critical
cost and performance data for those technologies, (3) an analysis
of the potential demand for specific demonstrated technologies
and (4) a development program to focus U.S. EPA research
and development efforts to foster the development of emerging
alternative technologies. The program is designed to be respon-
sive to the needs of the Superfund program, involves extensive
public input and includes technology transfer aspects to assist in
disseminating as much information as possible to the audiences
who need it.
REFERENCES
1. U.S. EPA, Office of Research and Development. Office of Solid
Waste and Emergency Response, "Draft Strategy and Program Plan,
Superfund Innovative Technology Evaluation Program," June 1986.
2. National Oil and Hazardous Substances Pollution Contingency Plan.
40 CFR Part 300; Federal Register. SO, Nov. 20,1985,47912.
360 ALTERNATIVE TECHNOLOGIES
-------
Applying Alternative Technologies at Superfund Sites
Donald C. White, P.E.
U.S. Environmental Protection Agency
Hazardous Response Support Division
Washington, D.C.
Jeffrey R. Dunckel
Timothy D. Van Epp
CH2M HILL
Reston, Virginia
ABSTRACT
In the past, the U.S. EPA has used land disposal often to man-
age Superfund hazardous wastes. Efforts are now under way to
use alternative treatment technologies to remediate Superfund
sites. This paper discusses some of these technologies and de-
scribes the U.S. EPA's efforts to encourage the wider applica-
tion of alternatives to land-based containment.
INTRODUCTION
Currently, CERCLA and the resulting NCP stipulate that re-
medial actions selected for Superfund must meet two key criteria:
(1) remedies must be proven technologies, and (2) remedies must
be cost-effective. Therefore, land disposal has been applied at
many Superfund hazardous waste sites in the past because it has
been considered "proven" and "cost-effective." Unfortunately,
these requirements often have inhibited the development and
application of new technologies that offer the promise of more
permanent solutions to the problem of managing Superfund haz-
ardous wastes.
However, revisions passed in 1984 to RCRA have placed cer-
tain restrictions on the use of land disposal. In addition, versions
of CERCLA now under consideration specify alternatives to
land disposal as the preferred remedial options at Superfund
sites. These changes to the U.S. EPA's mandate will significantly
increase the use of alternative technologies at such sites.
The U.S. EPA already has begun to use alternatives to land
disposal. Thermal destruction has been used for approximately
13% of all past removal actions and is planned for approximately
10% of all future remedial actions. Chemical and physical treat-
ment has been planned for approximately 9% of remedial ac-
tions. Although not usually considered an alternative to land dis-
posal, groundwater treatment now is being planned for almost
45% of all remedial actions.
The U.S. EPA has established the Superfund Innovative Tech-
nology Evaluation (SITE) program to develop and demonstrate
innovative and emerging technologies. Until results from the
SITE program are available, however, many existing technologies
will be applied to Superfund sites. The following examples illus-
trate ways that existing technologies can be applied in future re-
medial actions.
IN SITU ENHANCED VOLATILIZATION OF
VOLATILE ORGANIC COMPOUNDS
At the Verona Well Field site in Michigan, soils above an aqui-
fer are contaminated with volatile organic compounds (VOCs). A
soil vapor extraction system uses a number of vacuum wells to in-
duce a flow of air through the soil; the volatile contaminants are
expected to migrate from the soil into a piping system under
vacuum.
Although this volatilization technique is considered to be a new
process for treating VOC-contaminated soil, it is similar in prin-
ciple to some well-established technologies. Air stripping, for ex-
ample, uses a flow of air through a porous medium to strip VOCs
from a stream of water. Another similar technology is landfill gas
extraction, in which vacuum wells are used to remove gases from
the unsaturated soil zone.
The Problem
The Verona Well Field supplies potable water to most of the
City of Battle Creek, Michigan. In 1981, the well field was found
to be contaminated. Seven VOCs were identified as the primary
contaminants in the well field: 1,1-dichloroethane, 1,2-dichloro-
ethane, 1,1,1-trichloroethane, cis-1, 2-dichloroethylene, 1,1-
dichloroethylene, trichloroethylene and perchloroethylene. The
plume of contamination was nearly 1 mile long and 0.5 mile wide.
Five existing wells were incorporated into a "blocking well sys-
tem" designed to arrest the advancement of the contaminant
plume.
During the remedial investigation, two facilities operated by a
local solvent wholesaling company were identified as major
sources of contamination. VOC concentrations as high as 1,000
ppm were found in both groundwater and soil. It has been esti-
mated that the soils on the property contain a total of approxi-
mately 1,700 Ib of VOCs and that the groundwater in the immed-
iate vicinity of the property contains a total of 3,900 Ib of VOCs.
Using a groundwater extraction system alone would prevent the
continued migration of the plume. However, using only this sys-
tem would take a long time to solve the problem because of the
slow rate of leaching of contaminants from the soil to the ground-
water. Eliminating contaminated soils as a source of ground-
water contamination was required to expedite cleanup actions and
- restore the well field.
Why This Technology Was Selected
Several alternatives involving the use of "demonstrated tech-
nologies" to treat contaminated soils were considered to augment
the pumping and treatment of contaminated groundwater.
One alternative was to install a clay cap over the contaminated
soils to reduce infiltration by at least 90(7o, thus isolating the con-
taminated mass in the unsaturated zone soils. Another alterna-
tive was to excavate contaminated soils and dispose of them in
an on-site or off-site double-lined landfill, in compliance with
1984 RCRA amendments. It was estimated that 9,300 yd3 of soil
would have to be excavated and disposed under the landfill op-
tion.
The clay cap and landfill alternatives were rejected because they
merely isolated the contaminated soils and provided no real treat-
ALTERNATIVE TECHNOLOGIES 361
-------
merit. In addition, construction of an on-site land disposal facility
would be difficult because of the limited area of the property.
The installation of the clay cap would be difficult because of the
narrow range of clay moisture content required to construct an
effective cap.
Another remedial alternative evaluated—and considered to be
innovative—was in situ soil washing. This alternative would allow
clean water to percolate through the contaminated soil. VOCs
would be washed into the groundwater, which then would be col-
lected and treated by an extraction well system. This alternative
was rejected because it was projected that it would take 8 years to
reduce the contamination to acceptable levels.
Thus, the U.S. EPA selected the enhanced volatilization of
VOCs using a soil vapor extraction system to augment ground-
water treatment. Nearly complete removal of the contaminant
mass from the unsaturated zone is expected to occur within 1
year. Through the use of this process, with accompanying treat-
ment of groundwater, VOC contamination in groundwater is ex-
pected to be reduced to 100 pg/1 in only 3 years, and VOCs ac-
tually will be removed from contaminated soils.
The Technology
This technology reduces the level of contamination in the un-
saturated zone above aquifers by inducing, under vacuum, a flow
of air through the soil. Contaminants normally are removed from
the resulting air stream through the use of an activated-carbon
air treatment system.
Wells are installed through the unsaturated zone into the sat-
urated zone; screens are placed in the wells just above and slight-
ly below the water table; and a vacuum is placed on the well, air is
extracted and the contaminated air is treated before being re-
leased to the atmosphere. As more air is extracted from the soil,
the pressure surrounding the well is lowered, with two effects:
• Vapor pnote
carbon ootoptlon
column
• More contaminants volatilize from the soil moisture phase to
the soil vapor phase
• Clean air flows from the atmosphere at the surface, through the
contaminated soil (where it collects vaporized VOCs), and to
the well, carrying the volatile contaminants with it
With a clean source of air and a system of wells with overlap-
ping influences, the contaminants can be extracted from the un-
saturated zone.
Applvtng the Technology at the
Verona Well Field Site
The actual design of this system for the Verona Well Field will
be developed by the vendor. However, a general system was eval-
uated in the feasibility study.
A network of approximately eight air extraction wells will be in-
stalled at Verona Well Field for the withdrawal of air and volatil-
ized contaminants. The wells will extend approximately 2 ft below
the water table. Screens will be placed above the water table and
a short distance below the bottom of the unsaturated zone. A
conceptual diagram of this system is shown in Fig. 1.
This array of air extraction wells will be connected by an air-
tight transfer line to a vacuum pump. Because the VOCs are
collected through a vacuum system, contaminants can be con-
trolled at a single emission point, and the potential for fugitive
losses of air contaminants is reduced. The vacuum pump will be
used to draw 100 to 150 ftVmin of air from each well. The com-
bined flow of approximately 1,000 to 2,000 flVmin of contam-
inated air from the wells will be directed through a vapor phase
carbon adsorption treatment system before being discharged to
the atmosphere so that the resulting emissions meet applicable air
quality discharge limits. When the carbon has been regenerated in
a furnace, the VOCs will have been destroyed.
Initoll groundwater
extraction wvlli monitoring
well*. Interconnecting Rnei.
and other equipment
(*.) mdoDwelliand
ok withdrawal
ry»tem
Exljtlng Water Table
ContarrunoiedUrraturotodZone
Air extraction
weH» (typical)
——Groundwater ((traction Well
(Typical)
Sond and Grove! Aquifer (contaminated)
.•' Sandstone Aquifer ;:::;• ;•••:•;.;•..;;::•:;•,;
Figure 1
Enhanced Volatilization with Groundwater Pumping and Treatment will be used at the Verona Well Field Site in Michigan.
362 ALTERNATIVE TECHNOLOGIES
-------
Espotatioiu
This in situ enhanced volatilization process has been used suc-
cessfully in some hazardous waste applications but never at a
Superfund site. Enhanced volatilization requires conventional in-
stallation materials and equipment, periodic maintenance to en-
sure effective operation, periodic monitoring of discharge air to
guard against vapor breakthrough and periodic monitoring of soil
to confirm the expected decrease in contaminant concentrations.
The system is anticipated to be installed at the Verona Well Field
site in the spring of 1987.
The U.S. EPA anticipates that the system will remove over
90% of the estimated 1,700 Ib of VOCs in the unsaturated soil
zone within the first year of operation. The cost to construct and
operate this system for 1 year is estimated to be $410,000. Be-
cause this technology is expected to destroy the volatile organic
contaminants, annual operating and maintenance costs are not
expected.
SOLIDIFICATION/STABILIZATION OF
ORGANIC COMPOUNDS
Solidification/stabilization of soils contaminated with lead,
arsenic and PCBs is the alternative selected for the Pepper's Steel
and Alloys site in Florida. Use of this technology at the Pepper's
Steel site is innovative since it is to be used with soils contam-
inated with PCBs and other organic compounds. Solidification
physically reduces the movement of water through the soil mass,
reducing advective transport from the soil and decreasing the ex-
posed surface area and the diffusion potential. Stabilization
chemically binds constituents within the soil, reducing dissolu-
tion and diffusion rates.
The Problem
The site covers 30 acres of an unsewered industrial area ap-
proximately 10 miles northwest of Miami. Groundwater is about
5 to 6 ft below the ground surface and is part of the Biscayne
Aquifer, a sole-source aquifer that supplies all of Dade County's
water. Contaminants identified within the soil, sediments and
groundwater in and around the Pepper's Steel site include PCBs,
organic compounds and several heavy metals. PCBs, lead and
arsenic are present in soils in high enough concentrations to war-
rant remedial action.
Studies estimate that there are approximately 48,000 yd3 of
PCB-contaminated soils with concentrations greater than 1 ppm;
2%, or approximately 1,000 yd3, exceed SO ppm. In addition,
oily concentrations of PCBs were detected in test pits dug on-site.
It is estimated that 21,500 yd3 of soil are contaminated with
lead at concentrations exceeding 1,000 ppm. The volume of arsen-
ic-contaminated soil exceeding 5 ppm is estimated to be about
9,000yd3.
Why This Technology Was Selected
Several methods of disposing of contaminated soils were eval-
uated, including off-site disposal, solvent extraction of PCBs, on-
site incineration and off-site incineration. Off-site disposal was
eliminated from consideration because it was more costly than
other alternatives and it added transportation risks. Solvent ex-
traction was not selected because the technology was considered
to be experimental and costs were very uncertain. Incineration
was considered and rejected because of the problems associated
with the volatilization and release during incineration of heavy
metals contained in the soils. In addition, there still would be a
need to dispose of a significant amount of residuals from ma-
terials collected by the air pollution control system and from
metal-contaminated soils remaining after incineration.
Solidification/stabilization was the selected alternative because
it is expected to control the movement of constituents in soils by
solidifying soil particles and by stabilizing (chemically binding)
the constituents within the soil, thus reducing their mobility.
The Technology
Cement-based and pozzolanic materials have been used to
immobilize a wide variety of hazardous and radioactive wastes.
When tailored to a specific waste, these materials can produce a
matrix that resists leaching and degradation in a geochemical en-
vironment. However, these materials must be carefully matched
to the specific wastes to be immobilized and to the physical char-
acteristics of the site. In the past, solidification was not thought
to be applicable to organic contaminants.
A suitable mixture of solidification reagents and solidification
aids has been developed to lock the metals and PCB-contam-
inated soils from the Pepper's Steel site into a solidified mass.
This mixture has passed the engineering performance criteria and
leaching criteria established by the U.S. EPA for the site. The
U.S. EPA will continue to monitor groundwater in the vicinity of
the site to assure the effectiveness of this technology.
Applying the Technology at the
Pepper's Steel Site
At the Pepper's Steel site, this process will be used on soils with
levels of contamination exceeding 1 ppm PCBs, 1,000 ppm lead
or 5 ppm arsenic. Contaminated soils will be solidified/stabilized
and disposed of on-site. In addition, concentrations of PCB-con-
taminated oils that are uncovered during excavation will be re-
moved and disposed of off-site. In effect, soils with heavy metals
will be chemically stabilized, while soils contaminated with PCBs
will be solidified. Research conducted for this remedial action
established that a fixing agent consisting of 40% Portland cement
and 60% fly ash could be mixed with contaminated soils to form
a concrete-like material.
No liner will be used for an on-site disposal system because
solidified materials are expected to adequately prevent contam-
inant migration. Future institutional controls on land use and
future monitoring of the effectiveness of the remedy will be im-
plemented at the site.
Expectations
Tests conducted on solidified materials prepared with soils
from the site have indicated that this remedial action has a high
probability of success. Three leaching tests were conducted, in-
cluding the EP toxicity test. Soil samples were spiked with oils
containing 2,000 ppm PCBs to assure that the samples repre-
Figure 2
Contaminated soils from the Pepper's Steel Site in Florida were
solidified and tested for strength and leaching.
ALTERNATIVE TECHNOLOGIES 363
-------
sented a conservative oil loading. Under laboratory conditions,
the solidified material exceeded all engineering strength criteria
set for the project and was reported to have met leaching per-
formance criteria for lead, arsenic and PCBs. Testing of a con-
crete cylinder made with soils from the site is shown in Fig. 2.
The U.S. EPA has estimated capital costs for applying this
technology at the Pepper's Steel site to be $5.2 million, with an
annual cost of $260,000 during remediation. Project operation
and maintenance costs, primarily for post-remedial groundwater
monitoring, are estimated at $42,000 annually. Construction of
this remedial action is expected to begin next year.
ENCOURAGING THE USE OF AVAILABLE
ALTERNATIVE TECHNOLOGIES
While many alternative technologies currently are available for
use at Superfund sites, there often are impediments to their use.
These impediments involve such issues as liability, economic and
marketplace uncertainties, regulatory and permitting require-
ments, delisting, federal procurement and public acceptance.
Steps are being taken to remove these impediments. The U.S.
EPA is considering procedures "equivalent" to RCRA for delist-
ing treatment residuals at Superfund sites. "Up-front" con-
ditional delisting at off-site test and evaluation facilities is being
considered. A two-step formal advertising process is being estab-
lished to allow more flexibility in the procurement of technol-
ogies for Superfund cleanups. In addition, the U.S. EPA is try-
ing to streamline the permitting process and prioritize the per-
mitting of treatment technologies.
Another example of actions the U.S. EPA is taking to help
promote the use of alternative technology is the Superfund Inno-
vative Technology Evaluation (SITE) program, which has been
established to help overcome the problem created by the lack of
cost and performance data available for certain technologies.
Innovative technologies will be demonstrated at full scale and on
real wastes at Superfund sites; the first SITE demonstrations
are scheduled to begin by mid-1987.
Through such demonstrations, it is hoped that the commercial
availability of alternatives to land-based containment systems will
be expedited. The results from these tests will provide the cost
and performance data necessary to evaluate the techniques for use
at other Superfund sites. Once this cost and performance in-
formation is available, it must be delivered to those who can apply
it. The U.S. EPA is developing a technology transfer program
to accomplish this.
CONCLUSION
Congress, the U.S. EPA and the public all are seeking long-
term, reliable solutions to the problem of managing Superfund
hazardous waste sites. Land disposal of hazardous waste no
longer will be the preferred remedial alternative for Superfund
sites, and programs such as SITE have been initiated to encour-
age the development of information on technologies for future
use.
However, there are existing technologies that can be used at
Superfund sites now. The two technologies described in this paper
and others currently being applied at Superfund sites are evidence
that alternatives to land filling hazardous wastes exist. The U.S.
EPA is identifying and removing impediments that discourage the
wider application of alternative technologies. Future policies and
guidance will promote efforts to find more permanent solutions
to the disposal of hazardous wastes.
364 ALTERNATIVE TECHNOLOGIES
-------
Field Verification of the HELP Model for
Multilayer Hazardous Waste Landfill Covers
Nathaniel Peters, II
Richard C. Warner
Anna L. Coates
University of Kentucky
Agricultural Engineering Department
Lexington, Kentucky
ABSTRACT
Data obtained from two field-scale experimental landfill covers
are used to verify the ability of the Hydrologic Evaluation of
Landfill Performance (HELP) model to predict the performance
of a multilayer soil cover system. The HELP model uses algo-
rithms based on the physics of soil water movement to predict per-
colation into the waste layer and resulting leachate production.
The data used for HELP model testing were obtained from ex-
perimental covers, each consisting of a 2-ft soil barrier layer
overlain by a 2-ft sand drainage layer and topped with a 2-ft vege-
tated soil layer. The covers, which were 89 ft x 20 ft with a 3%
slope in the longitudinal direction, were large enough to require
field-scale compaction equipment. Extensive density and
moisture testing was conducted during construction of the soil
barrier layers. Measures employed in construction of the barrier
layer were later incorporated into the U.S. EPA's Construction
Quality Assurance for Hazardous Waste Disposal Facilities
Draft.
A thorough description of the procedure used for estimating
soil parameters is given. Major HELP model input parameters
were derived from soil analysis (particle size and specific gravity),
soil moisture characteristic curves and soil classification (USDA
and USGS). These initial parameters were employed in the HELP
model to predict values of runoff, drainage and percolation
volumes for the covers, which are compared with actual field
data.
The HELP model is shown to be capable of estimating drainage
from and percolation through, a multilayer soil cover for the
specific geometric conditions of this site. Advantages and limita-
tions of the HELP model are also presented.
INTRODUCTION
This paper presents an assessment of the HELP (Hydrologic
Evaluation of Landfill Performance) model based on intensely in-
strumented and monitored field-scale multilayer landfill covers.
Components of this analysis include: (1) results of the multilay-
ered cover experiment especially as affected by construction dif-
ferences; (2) procedures and results of the HELP model analysis,
including a thorough discussion of input parameters; (3) advan-
tages and limitations of the HELP model, and (4) conclusions.
The HELP model was developed under an Interagency Agree-
ment between the U.S. EPA Municipal Environmental Research
Laboratory, Cincinnati, Ohio and the U.S. Army Waterways Ex-
periment Station at Vicksburg, Mississippi.' The program is a
quasi-two-dimensional hydrologic model of water movement into,
through and out of a landfill. The HELP model was intended for
use as a design and review tool so that alternate landfill designs
could be rapidly evaluated with regard to expected amounts of
surface runoff, subsurface drainage and leachate. The program
models the hydrologic processes occurring in a landfill system in-
cluding surface runoff, infiltration, percolation, evapotranspira-
tion, soil moisture storage, lateral drainage and leachate produc-
tion.1 The experimental site used in this analysis concentrates on
the cover portion of a landfill. The cover system, if properly
planned, designed and constructed, is the primary line of defense
against the production of leachate and the associated need for
leachate containment and/or treatment.
Three multilayered, field-scale covers were constructed,2 and
have been comprehensively monitored for the past 22 months.
The multilayered cover experiment consists of three 6 m by 27 m
cells. Each cell has three layers: a lower clay barrier, a middle
drainage layer of sand, and an upper topsoil layer. All layers are
0.6 m thick.
A nearly automatic data acquisition system has been installed.
Data ports are scanned every second and summed for 5 min to 1
hr intervals, depending upon predetermined criteria which define
significant changes. Instrumentation provides data on in situ soil
moisture at 48 locations and soil temperature at 28 locations
throughout the multilayered cover profile. Data which allow for
construction of complete hydrographs of surface runoff, subsur-
face lateral drainage and leachate are automatically recorded. In
this study drainage is defined as that flow which is collected from
the sand layer above the barrier layer and leachate is the moisture
that percolates through the barrier layer and is collected in a lower
drain layer. Standard climatological data, including precipitation,
evaporation and wind velocity, are also collected. Thus, all hy-
drologic and climatologic information necessary for assessing the
predictive capability of the HELP model is collected by sensors
within this field-scale, multilayered cover system.
MULTILAYERED LANDFILL COVER
PERFORMANCE
Data Summary
The data discussed herein are for the 12-month period from Oc-
tober 1984 through September 1985. The HELP model com-
parisons are based on the second and third constructed covers.
The first cover was developed as a construction demonstration
cell and has only minimal instrumentation. A summary of hydro-
logic data from covers 2 and 3 is presented in Table 1.
Construction Effects
A cursory review of the data contained in Table 1 shows that
there is a significant difference in the overall performance be-
tween covers. Although the construction of the clay barriers in
covers 2 and 3 was quite similar, the method and sequence of top-
soil placement varied between covers. The resulting performance
differences have significant regulatory ramifications. Many
ALTERNATIVE TECHNOLOGIES 365
-------
Table 1
Hydrologlc Summary of Multilayer Cover Performance
Oct. 84 - June 85 July 85 - Sept. 85 ToUl
Q». (In.)
I) Precip.
2) Surf. Runoff
3) Drainage
4) Leachale
5) (2) + (3) + (4)
6) (1)- (5)'
Cover 2 Cover 3
30.22
1.66
16.64
1.80
20.10
10.12
30.22
0.89
9.54
1.31
11.74
18.48
Cover 2 Cover 3
14.15'
1.16
5.44
0.70
7.30
685
15.16
0.09
5.33
0.54
5.96
9.20
Cover 2
44.37'
2.82
22.08
2.50
27.40
16.97
Cover 3
45.38'
0.98
14.87
1.85
17.70
27.68
1 (I)-(S) - evapotranspiration + net change in toil moialure
2 Different amounts of artificial rainfall were applied using the modified Kentucky rainfall umu-
lator.
regulatory and research efforts have almost exclusively focused
attention on the clay barrier. Recent studies have been directed
toward laboratory and Field permeability, with respect to both
water and leachate, as well as field infiltrometer studies.3'4'5'6 The
draft "Construction Quality Assurance (CQA) for Hazardous
Waste Land Disposal Facilities"7 directed activities toward insur-
ing a field tested landfill cover, again with respect to the clay bar-
rier. Certainly, a well-documented clay liner is essential, but the
hydrologic performance of the complete multilayered landfill
cover system needs to be considered. This research documents
that construction activities with respect to the uppermost topsoil
layer can either benefit or impair the effective performance of the
clay barrier. The total performance of the multilayer system is af-
fected by each layer.
In order to understand the results presented in Table 1, the
reader must be aware of the differences between covers 2 and 3 in
regard to construction of the topsoil layer. In constructing the ex-
perimental multilayered covers, emphasis was placed upon the
clay barrier layer. The construction sequence and method was
carefully specified and well monitored to ensure consistent
results. The sand drainage layers did not differ between covers.
But the topsoil layer was only specified with respect to design
depth and slope; and the investigators, with the concurrence of
the U.S. EPA project officer, decided to illustrate the effects of
alternative topsoil construction techniques.
A skid-steer front end loader was used to simultaneously place
the sand drainage layer and the overlying topsoil layer. Starting
from the downsloped end of each cell, the sand was dumped to
the maximum distance of the loader's extension. Then topsoil was
placed on top of the sand and used as a driving surface for addi-
tional sand. Cover 2 was constructed by dumping almost the en-
tire 0.6 m layer of topsoil at the downslope end of the cover and
then progressing toward the upslope end, while constantly com-
pacting previously placed topsoil. The uppermost topsoil layer
was roto-tilled to about the 10- to 15-cm depth to prepare a seed-
bed for establishing vegetation. It is expected that such a con-
struction sequence created a hardpan approximately 15 cm thick
at about 15 cm below the surface. The remaining 30 cm below the
hardpan received less compaction due to its distance below the
tires of the loader. Thus, cover 2 was difficult to roto-till, and it
had difficulty in establishing a hardy grass cover, likely due to
poor root penetration and development.
On cover 3, rather than progressively placing a 0.6 m topsoil
layer along the entire cover length, a 15 cm "driving surface" was
constructed over the entire area of the cover. This layer became
very dense from being repeatedly driven upon. The remaining 45
cm topsoil layer was placed by driving the entire length of the cell,
dumping the material, and backing out. Since the uppermost 45
cm of topsoil in cover 3 was never driven over, it was not com-
pacted at all. Consequently, no topsoil seedbed preparation was
required nor was root penetration or development inhibited. A
vegetative cover was easily established on cover 3.
Another phenomenon observed on the surface of cover 2 was
the occurrence of desiccation cracks prior to establishment of
vegetation. If these cracks extend into, or through, the compacted
portion of the topsoil layer, they provide a ready pathway for
water to infiltrate into the relatively uncompacted lower portion
of the topsoil layer. These combined factors have resulted in a
relatively high hydraulic conductivity. The upper 45 cm of cover
3, which are relatively loose, are also expected to have a high hy-
draulic conductivity. But it is likely that the denser 15 cm layer, at
the bottom, impedes moisture movement into the sand, resulting
in moisture buildup into the upper topsoil layer. Moisture is thus
retained for a greater length of time in the topsoil of cover 3 and
subjected to evapotranspiration. Also, the looser soil and the
presence of soil moisture in the lower portion of the topsoil layer
has encouraged the development of a thick root system that deep-
ly penetrates the layer and extracts more soil moisture.
Figs. 1 and 2 demonstrate that differences in drainage between
covers 2 and 3 can be attributed to differences in evapotranspira-
tion. The graph of drainage for December (Fig. 1) when evapo-
transpiration is relatively low, shows drainage patterns which are
similar in both shape and magnitude for both covers. However, in
June (Fig. 2), cover 3 has significantly lower peaks and lower
IST»
Figure I
Drainage from Covers 2 and 3, December 1984
D
COVCK J
coven >
Figure 2
Drainage from Covers 2 and 3, June 1985
366 ALTERNATIVE TECHNOLOGIES
-------
overall quantity of drainage than cover 2. Figs. 1 and 2 also show
that drainage in cover 2 responds 1 to 3 days earlier than that of
cover 3.
HELP MODEL ANALYSIS
This section of the paper provides brief background material
on the methodology of the HELP model. Input parameters of the
HELP model encompass the areas of geometry, soil
characteristics and climate. Initial estimates of input parameters
are applied to the HELP model, and computer predictions are
compared to measured data for covers 2 and 3.
Input Parameters
The HELP model requires three types of input parameters: (1)
geometric, (2) soil characteristics and (3) climatic. The geometric
parameters are defined by design and construction criteria. Re-
quired input geometry encompasses: (1) number of layers, (2)
layer type, (3) thickness, (4) slope at the base of all drainage layers
and (5) cover area. The "layer type" is a numeric designation that
indicates whether a layer is represented by: (1) vertical percola-
tion, (2) lateral drainage, (3) soil barrier, (4) waste or (5) soil bar-
rier with an impermeable flexible membrane liner.1 The covers
constructed for this research all have three layers which are from
the surface downward: (1) a vertical percolation layer, (2) a lateral
drainage layer and (3) a barrier soil layer. All layers are approx-
imately 61 cm thick. The cover is sloped 3%. Therefore, the base
of the drain layer in the cover is also sloped 3%. Cover area is
nominally 167.2 m2. Actual cover area ranges from 167 m2 to
177.5 m2.
The soil parameters required by the HELP model include the
hydraulic conductivity (K) and field capacity (FC) of all layers,
the porosity of the vertical percolation layer and the lateral
drainage layer, and the wilting point (WP) and evaporation coef-
ficient (EVAPC) of the vertical percolation layer.
Field capacity and wilting point are terms used, mostly in
agriculture, to define levels of soil water available to plants. Field
capacity is defined as the water content remaining after free
drainage from an initially saturated soil has practically ceased.8
Wilting point is defined as the water content of a soil at which
plants wilt and fail to recover their turgidity when placed in a dark
humid atmosphere.8 Since these values are not easily determined,
they have been somewhat standardized by assuming that field
capacity is the water content corresponding to 33.5k Pa soil suc-
tion and that wilting point corresponds to 1520k Pa soil
suction.9-10 A pressure-plate apparatus was used according to the
procedure presented in Ref. 11, to determine the needed field
capacities and wilting points.
Porosity values were determined as a first step in the pressure-
plate procedure. The saturated water content, on a weight per
weight basis, was determined gravimetrically. Knowing the
saturated water content and the specific gravity of the soil, it was
then possible to calculate the volume per volume saturated water
content, which is approximately equal to the porosity. The bulk
density could then be obtained, based on the saturated sample,
and used to convert later (unsaturated) gravimetric water con-
tents to volumetric values. A limitation of the pressure-plate
method, for characterizing the barrier layer soil is that the
remolded sample is typically not compacted to maximum density.
Therefore considerable consolidation may take place as the
pressure is increased to various levels. Thus the estimated value of
field capacity must be somewhat in error. Fortunately, a sensitivi-
ty analysis showed that the HELP model is not sensitive to the
field capacity of the barrier layer.
The results of the pressure-plate analysis are more important
for the topsoil (vertical percolation layer) because the HELP
model uses all parameters for that layer. Since the topsoil layer is
normally not highly compacted in the field, the pressure-plate
procedure is more representative of field conditions. For purposes
of initial parameter estimation, the previously mentioned dif-
ferences between the topsoil layer of covers 2 and 3 were
disregarded. Once a soil layer is placed in the field, samples can be
taken to determine in situ porosity, field capacity and wilting
point. But a designer attempting to use the HELP model to com-
pare alternate designs prior to construction would not be afforded
this luxury. The estimated topsoil parameters, from the pressure-
plate experiments, were very similar to typical values given under
the USDA Soil Classification system for loam, while the particle
size distribution resulted in a USDA classification of silty loam.
The values of K and EVAPC corresponding to loam1 were used as
estimated parameters to describe the vertical percolation layer.
Parameters required in the lateral drainage layer (sand in this
case) are porosity, FC and K. Again, the porosity based upon a
saturated sample should relate well to the field case, because sand
will not consolidate much under pressure. In fact, the porosity
was estimated to be 0.340 while the typical value listed for coarse
sand (USDA textural class) is 0.351.' However, the estimated
value of field capacity using the pressure-plate appeared very low.
It was 0 .041 vol/vol as compared with a published value of 0.174
vol/vol for coarse sand. The very low number indicates that the
sand has almost no capillary suction. Particle size analysis of the
sand used resulted in a USDA soil textural classification of
"sand." Schroeder et a/.1 gives 6.62 in/hr as an estimated value of
K for that USDA class. A sensitivity analysis showed that for this
geometry the HELP model was not very sensitive to the K value
of the drain layer* so the value of 4.7 x 10 ~7 cm/sec was used.
The one parameter not yet discussed is the K of the barrier soil
layer. As with many of the previous parameters, it is impossible to
know what that value is prior to construction of the layer. The
clay soil which was used in the experimental covers was tested and
classified as a CH soil according to the Unified Soil Classification
System. Such soils are expected to be "practically impermeable"
when compacted, which generally means having a K less than
1 x 10-7 cm/sec (1.417 x 10-4 in/hr).12 Therefore, i x 10-7
cm/sec was used as the input parameter for the HELP model.
Table 2 gives a summary of the design soil data used as input to
the HELP model.
Table 2
Initial HELP Model Inputs
Parameter
Porosity
Field Capacity
Wilting Point
K (in/hr)
Evaporation Coeff. (cm/sec)
Vegetation
Evaporation Zone
Curve Number
Vertical Perc.
Layer
0.523
0.376
0.217
0.21
4.5
Good Grass
25cm
SI (default)
Drain
Layer
0.34
0.174
— -
6.62
— -
— -
_—
Barrier
Layer
—
0.352
0.000142
— -
....
—
—
The primary climatologic data required by the HELP model are
daily precipitation, mean monthly temperatures and mean
monthly insolation. The daily temperature and insolation are esti-
mated from mean monthly values by fitting the monthly values to
a simple harmonic curve with an annual period.1 The precipita-
tion used is the actual daily amount recorded by the tipping
bucket raingauge.
ALTERNATIVE TECHNOLOGIES 367
-------
HELP Model Performance with
Initial Parameter Selection
The capabilities of the HELP model were first tested using the
initial parameters listed in Table 2 and on-site daily precipitation
data for October 1984 to June 1985. Comparisons were based on
the overall model performance, i.e., totals for the entire tested
time frame and not on a daily output basis. The overall model
predictions are compared to measured cover performance, for
covers 2 and 3. As can be seen in Table 3, the HELP model, using
these initial parameter estimates, underpredicted surface runoff,
drainage and leachate production. This underprediction of flows
for both covers indicates that the HELP model, using estimated
parameters and Lexington, Kentucky climatic data, overpredicted
evapotranspiration. The total predicted HELP outflow quantities
were underestimated by 56%, and 24%, for cover 2 and 3, respec-
tively.
Table 3
Initial HELP Model Test (Oct. 19M - June 1985)
Results Runoff Dnlnift * Error Lnchite ft Error Toul
(In.) (lo.) (In.) (la.)
Error
Cov. 2
HELP
Model
Co\. 3
HELP
Model
1.66
0.58
0.89
0.58
16.64
7.53
9.54
7.53
1.80
- 55 0.83
1.31
-21 0.83
20.10
-54 8.94
11.74
-36 8.94
-56
-24
HELP calculated leachate quantities were also underpredicted by
54% and 36% for covers 2 and 3, respectively. However, these
HELP model results were based on "best estimates" of what con-
structed cover parameters might be expected to be and not on in
situ measurements, i.e., from the perspective of a knowledgeable
design engineer. In this regard, model predictions within 50% are
considered quite good.
Additional HELP Model Tests
Additional testing of the HELP model included testing of
default procedures, calibration testing, and a sensitivity analysis.
Soil samples were tested and classified according to USDA soil
textural class and the HELP model was applied using strictly
default soil parameters. The default procedure of specifying a
compacted layer was tested based on the construction procedures
for covers 2 and 3. A compacted vegetative layer was specified for
cover 2 and model results were compared to field performance.
Covers 2 and 3 were then treated separately in model calibrations.
Tests indicated that realistic variations in input parameters could
result in model predictions closely matching actual data. A sen-
sitivity analysis was then performed on the calibrated input
parameters. For a complete discussion of these test procedures
and results see the final U.S. EPA project report.13
ADVANTAGES AND LIMITATIONS
OF THE HELP MODEL
Advantages
The HELP model has several advantages which make it a
potentially valuable design tool. The model uses published
methods to model the effect of all the major hydrologic processes
of moisture movement and balance in a landfill. The model ties all
of the processes together into a computer program which makes it
feasible to model long time periods. Especially important is the in-
clusion of a daily evapotranspiration algorithm in facilitating
long-term simulations.
The HELP model is designed to allow for various layer con-
figurations and drainage lengths that are typical in a landfill
design. This flexibility allows for very quick comparisons of
drainage and leachate predictions for alternative landfill designs.
The computer program includes default climatologic data for 102
cities and it has detailed default data for soil characteristics. The
default data also facilitate relative comparisons based upon dif-
ferent climates or different soil types.
Limitations
Some of the algorithms used by the HELP computer program
to model the various components of water movement have
specific limitations. One potential limitation of the HELP model
is that water is not allowed to move laterally in a designated ver-
tical percolation layer. That limitation is not a serious problem
for this particular study. However, in many typical landfills a
drainage layer is not used between the vegetated layer and the bar-
rier layer. If there is a significant difference in hydraulic conduc-
tivity between the two layers, the upper layer would certainly act
as a lateral drainage layer (assuming the barrier layer is sloped).
This particular limitation can be partially overcome by separating
the vegetated layer into two segments for use in the model. The
upper segment would be a lateral drainage layer with the same
hydraulic conductivity.
Another limitation indicated by results of this experiment is
that flow in the topsoil layer may not be strictly idealized porous
media flow. However, that is a limitation of any model for satur-
ated/unsaturated soil water movement which is based upon the
mathematical equations for porous media flow. Potential users of
the HELP model should be aware that the predictions have much
greater chance of validity if all soil materials (including the topsoil
layer) are placed as uniformly as possible.
Finally, the inclusion of default soil data is a very attractive
feature of the HELP model. However, the parameters are
presented in the HELP model manual,1 for the various USDA
textural classes, as if they are established values. An inexperienced
model user may incorrectly assume that, if the soil can be classi-
fied according to textural class, its characteristics are "known."
Yet practically any natural soil type can be worked or compacted
such that the soil characteristics will not be consistent with those
listed in the manual.
CONCLUSIONS
The HELP model proved to be capable of estimating drainage
and leachate production based on initial parameter estimates of
tested cover materials. The HELP model performs well, for this
application and could be used to document the expected perfor-
mance of alternative landfill cover configurations. It is recom-
mended that a range of feasible input parameters be tested to pro-
duce estimates of leachate production on which future recycling,
treatment and/or hauling cost can be projected.
ACKNOWLEDGMENT
Funding for this research came from the United States Environ-
mental Protection Agency, Hazardous Waste Engineering Re-
search Laboratory, Cincinnati, Ohio. The EPA Project Officer,
Dr. Walter E. Grube, provided valuable guidance throughout the
course of this work.
REFERENCES
1. Schrocder, P.R., Morgan, J.M.. Walski, T.M. and Gibson, A.C.
"The Hydrologic Evaluation of Landfill Performance (HELP)
Model," Vol. 1, EPA/530-SW-84-009, U.S. EPA, Washington,
DC. 1984.
2. Warner, R.C., Wilson, J.E., Peters, N., Sterling, H.J., Grube,
W.E., "Multiple Soil Layer Hazardous Waste Landfill Cover: De-
368 ALTERNATIVE TECHNOLOGIES
-------
sign, Construction, Instrumentation and Monitoring," In: Land
Disposal of Hazardous Waste-Proceedings of the Tenth Annual Re-
search Symposium. EPA-600/9-84-007, U.S. EPA, Washington,
DC, 1984.
3. Anderson, D.C., Sai, J.O. and Gill, A., "Surface Impoundment
Soil Liners." Report to U.S. EPA by K.W. Brown and Associates
Inc., EPA Contract #68-03-2943, 1984.
4, Daniel, D.E., "Predicting Hydraulic Conductivity of Clay Liners,"
J. ofGeotech. Eng. 110, 1984, 285-300.
5. Daniel, D.E., Anderson, D.C. and Boyton, S.S., "Fixed-Wall Ver-
sus Flexible-Wall Permeameters," In. Hydraulic Barriers in Soil
and Rock. American Society for Testing and Materials, ASTM
STP 874, 1985.
6. Day, S.D. and Daniel, D.E. "Field Permeability Test for Clay Lin-
ers." In: Hydraulic Barriers in Soil and Rock. American Society for
Testing and Materials. ASTM STP 874, 1985.
7. U.S. EPA, Construction Quality Assurance For Hazardous Waste
Land Disposal Facilities — Public Comment Draft. EPA/530-SW-
85-021. U.S. EPA, Washington, DC 1985.
8. Brady, N.C., The Nature and Properties of Soils, 8th ed., MacMil-
lan Publishing,' New York, NY, 1974.
9. England, C.B., Land Capability: A Hydrologic Response Unit in
Agricultural Watersheds," ARS 41-172, Agricultural Research
Service, USDA, 1970.
10. Lutton, R.J., Regan, G.L. and Jones, L.W., "Design and Con-
struction of Covers for Solid Waste Landfills," EPA-600/2-79-
165. U.S. EPA, Washington, DC 1979.
11. Richards, L.A. "Physical Condition of Water in Soil." In: Meth-
ods of Soil Analysis - Part I. C.A. Black, Ed., American Society of
Agronomy, 1965.
12. Lambe, W.T. and Whitman, R.V., So/7 Mechanics, SI Version.
John Wiley and Sons, New York, NY, 1979.
13. Warner, R.C. et al., "Construction, Monitoring, and Modeling of
Multilayer Landfill Covers for Hydrologic Effectiveness," Final
Project Report. U.S. EPA, Washington, D.C., Report due Jan.
1987.
ALTERNATIVE TECHNOLOGIES 369
-------
Application of Fluorescence and FT-IR Techniques to
Screening and Classifying Hazardous Waste Samples
DeLyle Eastwood, Ph.D.
Russell Lidberg
U.S. Army Corps of Engineers
Missouri River Division
Omaha, Nebraska
ABSTRACT
Fluorescence spectroscopy has been applied successfully to
screening, classifying and semiquantitating hazardous waste sam-
ples from U.S. Department of Defense sites. Fluorescence meth-
odologies provided a cost-effective and time-saving alternative
for detecting, classifying and semiquantitating real world samples
containing petroleum oils or classes of hazardous chemicals which
are relatively strong fluorescers such as polychlorinated biphenyls
(PCBs) or aromatics, etc. In addition to standard emission meth-
ods, excitation and synchronous scanning techniques were
employed as well as both room and low temperature measure-
ments.
Fourier transform infrared spectroscopy also was used for con-
firmation. It is a complementary technique which is sensitive to
nonaromatic and nonfluorescing species.
Reference spectral libraries were developed in-house for refer-
ence petroleum oils for both fluorescence and infrared spectra.
Spectral search routines based on appropriate feature sets and
similarity measures are being developed and tested. Pattern recog-
nition parameters used for spectral searches and comparisons
include such factors as spectral areas, peak positions and ratios
and angular distances between spectra regarded as vectors in n-
dimensional space.
INTRODUCTION
This paper is a continuation of a series of studies by one of the
authors on pattern recognition and forensic identification for
petroleum oils and hazardous chemicals by various spectroscopic
methods including fluorescence, low temperature luminescence
and infrared spectroscopy which resulted in several publica-
tions'"* and ASTM standard methods.9'10 In addition, many tests
and publications have dealt with general considerations of
fluorescence spectroscopy to identify and classify oils"20 and
chemicals21'26 and similarly with infrared spectroscopy of petrol-
eum products27"3'4 and hazardous chemicals." "
The present study extends a similar pattern recognition ap-
proach to topics of interest to the Corps of Engineers for U.S.
Department of Defense (U.S. DOD) environmental projects
under Defense Environmental Restoration Account (DERA).
For these environmental projects, it is desirable to classify crude
and refined petroleum oils and related fuels as to type and prob-
able origin, to classify or identify hazardous chemicals and some-
times to quantitate concentrations of oils and chemicals present in
soil, water and unlabelled drums.
The present study has successfully applied fluorescence (emis-
sion, excitation and synchronous), low temperature lumines-
cence and, to a limited extent for comparison, Fourier transform
infrared (FT-IR) spectroscopy to screening, classifying and semi-
370 SITE REMEDIATION TECHNIQUES
quantitating hazardous waste samples from DERA sites in Alaska
and Kansas. Fluorescence methodologies provide a relatively in-
expensive and quick approach to detect, screen, classify and semi-
quantitate environmental samples involving petroleum-derived
constituents or hazardous chemicals having fluorcscmg aromatic
or heterocyclic ring systems, e.g., phenols or polychlorinated bi-
phenyls (PCBs).
In addition to standard emission methods,6- '• ** less common
techniques such as synchronous and excitation spectra were util-
ized at both room and low (77 °K) temperatures. As has been
demonstrated by several authors including Lloyd,17- l8 Vo-
Dinh20 and East wood,'•2 synchronous spectra permit more spec-
tral structure and hence enhanced pattern recognition capabili-
ties. Low temperature luminescence spectra1- '• M generally have
greater emission intensity, more spectral structure and phosphor-
escence as well as fluorescence, thus expanding the number of
chemicals which can be studied by molecular emission techniques.
With appropriate reference standards and emission techniques,
petroleum oils and fluorescent hazardous chemicals also can be
quantitated over a range from 100 ppm to a few ppb even in diffi-
cult matrices such as river sediments, therefore accomplishing by
a simple technique what would be difficult to do by standard
GC-MS methodology.
For comparison vsiih real world samples for classification and
pattern recognition purposes, there is an evident need for appro-
priate spectral reference libraries of known petroleum oils and
hazardous chemicals of known purity. Obviously, these refer-
ence spectra should be taken under the same instrumental and
experimental conditions and preferably should be measured on
the same instrument. This is especially important for mixtures
such as oils where the emission spectrum will vary with excitation
wavelength and bandpass. Matrix effects, concentration effects,
possible solvent shifts and effects of emulsions and possible
weathering effects must be taken into account. Fortunately,
earlier studies of weathering effects on fluorescence and disper-
sive infrared3'*• "• M- M spectra of petroleum oils allowed estima-
tion of the extent of these effects.
Spectral search routines for classification based on appropriate
feature sets and similarity measures were developed and tested.
For fluorescence, these included such pattern recognition tech-
niques as computer library searches and comparisons of factors
such as spectral area, peak positions and angular distances be-
tween spectra regarded as vectors in n-dimensional hyperspace.
Preliminary studies on FT-IR were used for confirmation and
as a complementary technique. Appropriate libraries of reference
petroleum oil spectra are being developed in-house and, for FT-
IR, libraries of hazardous chemicals are already available. Pattern
recognition techniques for infrared spectra of petroleum oils in-
cluded peak positions and peak ratios and angular distances us-
-------
ing 20-dimensional space (based on 20 infrared peaks commonly
used for oil identification).
EXPERIMENTAL
Instrumental Conditions—Fluorescence
A SPEX Fluorolog 112A corrected spectrofluorometer was
used for all fluorescence data collected. The instrument consisted
of a single excitation monochromator and a double emission
monochromator. The gratings were ruled at 1200 grooves per mm
and were blazed at 250 nm (excitation) and 500 nm (emission).
The excitation source consisted of a 150 W ozone generating
Xenon lamp. Photomultiplier tubes used for both emission and
reference detectors were Hamamatsu type R928P and were oper-
ated at 950 v and 500 v, respectively.
The spectrofluorometer was interfaced to a SPEX DM IB spec-
troscopy laboratory coordinator which was programmable in
Basic. This data system provided digitized spectral data, disc stor-
age and ease of spectral manipulation.
Calibration of wavelength accuracy was checked by analyz-
ing anthracene in cyclohexane at 1 Mg/8- An ovalene sample of
approximately 10~7 M concentration, which was embedded in a
polymethylmethacrylate matrix, also was analyzed periodically.
These results indicated the wavelength accuracy to be ± 1.0 nm.
Scans were performed using a 0.5 nm step interval with a 0.75
second integration time at each step. This scanning procedure
was equivalent to a scan speed of 40 nm/minute. Slit widths used
for emission and synchronous scans were 1.25 mm (bandpass =
4.5 nm) and 0.5 mm (bandpass = 0.9 nm) for excitation and
emission monochromators, respectively. For excitation scans,
the slit widths were reversed. These slit widths were used through-
out unless otherwise stated.
Room temperature spectra were collected using a standard
10 mm quartz cell. Optical dewars and fluorescence-free fused
silica sample tubes, used for work at liquid nitrogen tempera-
tures, were obtained from SPEX. Emission spectra were excited
for most samples at 254 nm, using an excitation wavelength of
230 nm if the sample appeared to be a lighter fuel (e.g., JP-4 jet
fuel). An excitation wavelength of 270 nm was used for
Aroclors® . The emission scan was then collected from 280 nm
to 600 nm. Synchronous spectra were collected by scanning both
monochromators with a A X of 25 nm and collection emission
data from 275 nm to 625 nm. Excitation scans were performed by
detecting at the wavelength corresponding to the strongest emis-
sion peak and scanning the excitation monochromator from
220 nm to within 10 nm of the detection wavelength.
The solvent background first was subtracted from the sample
spectra and the spectra then was normalized to make the maxi-
mum peak equal to one. This tended to remove any variability in
spectral area arising from different emission intensities or minor
concentration effects for different samples. From these normal-
ized spectra, maximum peaks, secondary peaks, peak shoulders
and spectral areas were determined. By comparing spectra digi-
tized every 2 nm for a total of 160 points (for emission spectra)
or 175 points (for synchronous spectra) to a similar vector in n-
dimensional hyperspace, angles between vectors were calculated
for classification purposes.
Instrumental Conditions—FT-IR
A Digilab FTS 60 FT-IR spectrometer was used to collect all
infrared data. The instrument used a Michelson interferometer
with a beam splitter consisting of a Ge film on a KBr substrate.
The source was a high temperature water cooled element, and
the detector was a deuterated triglycine sulfate pyroelectric bolo-
meter (DTGS). The spectrometer was interfaced to a Digilab 3200
Data Station with a 40 Mbyte Winchester disk and was program-
mable in C. All spectra were collected using a resolution of
2 cm"1 with 64 scans, a scan speed of 5 kHz and a low pass filter
of 1.12 kHz. Instrument calibration was checked by running a
polystyrene film and checking peak positions. Peak wavenum-
ber accuracy was found to be ± cm~ ' over the entire spectrum.
Chemicals and Oils
Solvents used were all spectroquality or purer. Acetone and
dichloromethane were obtained from Mallinckrodt (SpectAR® ),
cyclohexane from Burdick and Jackson (high purity) and methyl-
cyclohexane from Baker (Photrex® ). Aroclor® (Monsanto
Co.) standards were obtained from Chem Services, Inc. The
anthracene used for fluorescence calibration was from Aldrich
(99.9%). The ovalene plastic standard also used for fluorescence
calibration was from Starna Cells, Inc.
Reference oils were obtained from the Environmental Protec-
tion Agency (EMSL-Cincinnati), Oak Ridge National Labora-
tory (Martin-Marietta) and the U.S. Coast Guard Research and
Development Center. Reference oils were chosen to include repre-
sentative samples from the principal types of petroleum oils (light
fuels, heavy fuels and crudes).
PATTERN RECOGNITION
Spectra of petroleum oils usually can be classified by a trained
observer using the simple overlay method and visually comparing
the closeness of match. In order to compare and classify spectra
more objectively, systematic mathematical approaches have been
developed.5' 39> *° Various factors such as peak wavelengths, peak
ratios, spectral areas and angular distances (or angles) between
spectra regarded as vectors in n-dimensional hyperspace were util-
ized. Peak positions and vectors in n-dimensional space can be
applied to both fluorescence and infrared spectra, with peak
ratios playing an important role in characterization by infrared
spectroscopy. Spectral areas were reserved for use with fluores-
cence spectra because there are fewer distinct fluorescence peaks
as opposed to infrared making the total spectral envelope of more
importance for fluorescence spectra.
A spectrum can be considered a vector in n-dimensional space
corresponding to n-digitized intensity values of the spectrum.
Two spectra with identical intensities at each digitized point over
the same spectral range can be considered identical, correspond-
ing to an angular distance in n-dimensional space of zero. Conse-
quently, as the difference in spectral structure increases, the angle
between vectors increases. The angle between two vectors X and
Z can be defined as:
_ ' _
= arccos X • Z
This approach was used successfully for fluorescence and infra-
red spectra on the weathering effects of petroleum oils by Killeen,
et al?< 34> 39 A similar approach comparing two other similarity
measures was used by Sogliero and Eastwood7- 8 for hazardous
chemicals. Since members of a class of oils or chemicals are spec-
trally similar, such an approach can be used for classification, for
forensic identification or for estimating weathering effects.
Using these criteria, peaks corresponding to maximum inten-
sity, areas of spectra normalized as described previously and
classifying unknown oils to appropriate spectral libraries of
known reference oils by angles in n-dimensional space have been
utilized for emission and synchronous spectra. Data are summar-
ized in the Results section.
SAMPLE PREPARATION
Fluorescence — Reference Oils
Standard solutions were prepared from the reference oils at a
SITE REMEDIATION TECHNIQUES 371
-------
concentration of 20 pg/g.9 This sample preparation was done by
diluting 1.6*1 mg of the oil to 100 mL with cyclohexane. Low
actinic volumetric flasks were used to prevent photodecompo-
sition. All samples were analyzed within 5 hr of preparation. For
low temperature luminescence, spectroquality methylcyclohexane
was used as the solvent. Methylcyclohexane was used because it
forms a clear glass at liquid nitrogen temperatures (77 °K).J> **
Aroclor® Reference Solutions
Aroclor® reference solutions, for PCB analysis, were prepared
by appropriate dilutions to concentrations of 10-30 pg/g, using
cyclohexane at room temperature of methylcyclohexane at low
temperature.
Samples—Oils
Real world samples obtained for analysis were divided into
three basic groups: neat samples that appeared to be pure oils;
soil samples; and liquid samples (many containing a water phase)
that were not pure oils.
Neat samples, those considered to be single phases, were pre-
pared identically to the reference standards. The samples were
diluted to 20 /tg/g with cyclohexane in low actinic volumetric
flasks and treated as stated above.
Soil samples were extracted with cyclohexane using 10 grams of
soil and 20 ml of cyclohexane with a 30 min extraction period
with stirring. This solution then was Filtered through glass filter
paper (Whatman glass microfiber filters 934-AH) which had been
prerinsed with solvent. If necessary, the solution concentration
was adjusted to bring the oil concentration into a range where the
sample and references spectra would be comparable.
Liquid samples that did not fall into the neat oil category were
visually examined to determine the primary constituent. If an oil
layer was obvious, it was removed and a 20 /tg/g solution was
prepared as with the neat oil samples. If no oil was visually appar-
ent, the sample was scanned to determine if the levels of oils were
above detection levels. Where the sample showed no obvious
fluorescence, the sample was extracted with cyclohexane and the
organic portion was re-examined. Occasionally, a sample con-
tained no apparent oils but did show evidence of other fluorescing
species such as dyes. The excitation and emission wavelengths
corresponding to peak maxima for the excitation and emission
spectra were then determined and spectra analyzed for each. Lit-
erature21'a> M was then consulted to determine the unknown.
Aroclor* Soil Samples
Soil samples were extracted with cyclohexane followed by treat-
ment of the filtrate with an equal amount of concentrated sul-
furic acid. This degrades oils and other possible interfering fluor-
escing species also extracted from the soil. The emission spectrum
was then obtained by exciting at 270 nm.
FT-IR Oil Spectra
Reference oils were analyzed using a demountable cell with KBr
windows and a 0.05 mm Teflon spacer. Samples then were scan-
ned under the conditions noted under the instrumental con-
ditions section over the range of 4000 cm ~' to 500 cm ~'
RESULTS
Fluorescence/Luminescence
Use of fluorescence spectroscopy for forensic identification
and classification of petroleum oils was proposed by Lloyd11'18
and has since been used by Eastwood,'•*• *• 6 Vo-Dinh20 and
others."'16 ASTM methods have been developed for identifica-
tion. Eastwood review article1 lists many earlier references for
oil fluorescence. The oil classification method used in this paper
is based on a modification of ASTM method D3650-78' designed
for forensic identification of water-borne oils. It assumes that a
sufficient library of corrected fluorescence spectra of reference
oils is available or can be generated in-house.
Twenty-nine reference oils were studied primarily by emission
spectra excited at 254 nm or 230 nm and also by synchronous
emission spectra (A X = 25 nm). In addition, published and un-
published spectra generated under similar conditions were avail-
able for comparison. It was known that low temperature lumi-
nescence spectra1-*•u would yield additional spectral structure if
needed.
Tables 1 and 2 list the important spectral features for emission
and synchronous spectra for the 29 reference oils used in this
study. These features include maximum peak wavelengths, wave-
lengths for secondary peaks and shoulders and the relative area
under the normalized spectral envelope. Table 1 shows that spec-
tra of diesel fuels and No. 2 fuel oils are structurally similar and
that the heavier oils (No. 6 fuels and crudes) also tend to be simi-
lar to each other. Fig. 1 represents a typical No. 2 fuel oil and a
typical No. 6 fuel oil. In this case, the special differences are
obvious, thus allowing easy classification.
Fig. 2 shows two No. 6 fuel oils with slight emission spectral
differences. Fig. 3 shows a Prudhoe Bay crude oil that has analo-
gous spectral features to the No. 6 fuels in Fig. 2. Such close cor-
respondence in emission spectra is very common and thus can
lead to classification errors. Fig. 3 presents two crude oils that do
have obvious spectral differences. The South Louisiana crude is
a lighter crude than the Prudhoe Bay crude and, therefore, has
its maximum peak at a shorter wavelength corresponding to a
higher proportion of low molecular weight aromatics.
As mentioned above, this ambiguity between emission spectra
of No. 6 fuels and some crudes may lead to classification errors.
Table 2 and Fig. 4 through 6 (which show the same oils as Fig. 1
through 3) indicate that synchronous emission spectra can pro-
vide more spectral structure than the more commonly used emis-
sion scans, therefore providing more structure for spectral classif-
ications. Of particular interest is the difference between the max-
imum peak wavelengths of the No. 6 fuel oils in Fig. 5 and the
Prudhoe Bay crude in Fig. 6. This difference has increased to ap-
proximately 50 nm in the synchronous spectra where, as in the
emission spectra, the maximum peak positions were identical.
Thus, emission spectra often are sufficient to differentiate be-
tween dissimilar oil types, but a more definitive classification may
be made in conjunction with synchronous spectra.
Fig. 7 through 10 provide real world examples comparing un-
known oil samples with known samples in our spectral library.
Fig. 7 shows that extraction from soil by the method given in this
paper yields recognizable spectra. Fig. 8 shows a water sample
analyzed directly without sample preparation which is compar-
able to a No. 2 fuel oil. Fig. 9 is interesting because it compares a
real world sample with JP-4 jet fuel less commonly analyzed by
fluorescence and potentially more subject to weathering. Fig. 10
shows a close correspondence between a known Prudhoe Bay
Crude oil with an unknown real world sample which was received
in isopropyl alcohol.
When the oils are more extensively weathered or when the
classification of the oil is less clear, a more quantitative approach
may be necessary. Weathering effects on fluorescence spectra of
weathered oils have been described in previous papers includ-
ing ASTM method 3650-78 and papers by Eastwood10 and Kil-
leen3'39 and have indicated that fluorescence spectra of oils (after
weathering in a thin film or water) are still distinguishable for
identification purposes after periods from 2 days (for No. 2s) to
2 weeks or even longer (for No. 6s).
Killeen, et a/.' proposed a pattern recognition approach which
allowed the possibility of correcting fluorescence spectra for
weathering, given weathering data on a similar oil. This approach
372 SITE, REMEDIATION TECHNIQUES
-------
Table 1
Fluorescence Spectra: Emission Characteristics of Typical
Petroleum Oils1
Table 2
Fluorescence Spectra: Synchronous Emission1 Characteristics
of Typical Petroleum Oils
LAB NO.
101
102
103
104
105
106
107
108
109
TYPE
JP-4 FUEL'2'
DIESEL FUEL
DIESEL FUEL
DIESEL FUEL
DIESEL FUEL
N0.2 FUEL
N0.2 FUEL
N0.4 FUEL
M0.6 FUEL
WAVELENGTH (m)
PRIMARY PEAK
( ±1 m)
328
314
311
307
307
308
308
355
358
NAVELEN3TH (m)
SECONDARY PEAKS,
SHOULDERS (SH)
( ±1 m>)
337
324(SH),352(SH)
324(SH)
324(SH), 349,382,404
323 (SH)
313(SH), 352,369
308,324,407,440 (SH)
314,374, 402(SH) ,
NORMALIZED
AREA
79.8
86.4
116
97.4
122
101
102
241
233
LAB NO.
101
102
103
104
105
106
107
108
TYPE
JP-4 FUEL
DIESEL FUQ*
DIESEL FUEL
DD3SEL l^ll*!! •
DIESEL FUEL
NO. 2 FUEL
N0.2 FUEL
NO. 4 FUEL
WAVELENGTH (ran)
PRIMARY PEAK
292
325
312
324
324
325
316
325
WAVELENGTH (nra)
SECONDARY PEAKS,
SHOULDERS (SH)
( ±1 nm)
323
317,349(SH)
3 23, 349 (SH)
306, 346 (SH)
306,346,383,403
306,347 (SH)
326, 348 (SH)
309(SH), 345,381,411
431,438,463
NORMALIZED
AREA
69.0
68.9
77.7
70.7
72.4
75.7
70.9
170
110 N0.6 FUEL 357
111 N0.6 FUEL 356
0.3
444 (SH)
316,374,407,444(SH) 218
314,345(SH),371(SH) 160
109
110
ND.6 FUEL 419
N0.6 FUEL
417
313,330,362,383, 262
447(SH),487(SH),505,
516
315,331,346,360,383, 238
411,446,490(SH),505,
516
112
113
114
115
116
117
116
119
120
121
122
123
124
125
126
127
128
129
Ml
N0.6 FUEL
LOW SULFUR
N0.6 FUEL
LOH SULFUR
N0.6 FUEL
MED. SULFUR
ND.6 FUEL
2.9% SULFUR
DOMESTIC
PRODUCT
N0.6 FUEL
HIGH SULFUR
NO. 6 FUEL
HEAVY
ND.6 BUNKER
BUNKER FUEL
BUNKER C
RESIDUAL
ARABIAN LIGHT
CRUDE
ARABIAN,
SAFANTVA
HEAVY CRUDE
CALIFORNIA,
KERN RIVER
CRUDE
CALIFORNIA,
HILMIN3ION
CRUDE
IRANIAN HEAVY
CRUDE
ram SLOPE
AUSKA CRUDE
PRUDBOE BAY
CRUDE
SCOTH
LOUISIANA
CRUDE
WHKQC,
RECLUSE
CRUDE
Bxcited at 254 ran exc
357
314,372, 445(SH)
215
111
ND.6 FUEL
0.3% SULFUR
311
330,347,353,378(SH), 166
413 (SH)
CARIBBEAN PRODUCT
357
356
364
357
362
359
357
363
356
358
358
357
358
357
357
357
357
ept where
315,374,454
314,372,451
315(SH), 376,408,446
315,375,404,442(SH)
316,364, 405(SH), 453
315,373, 444(SH)
315 (SH), 378,408,
440 (SB)
316(SH), 378,407,451
312,372,448
313,372,453
315,375,447
315,373,445(SH)
315,373,453
315,368, 445(SH)
315,372,445(SH)
313,326 (SH), 346 (SH)
374,445 (SH)
313,371(SB)
indicated
234
232
270
246
295
212
232
286
231
261
222
211
217
193
212
232
199
112
113
114
115
116
117
118
119
120
121
122
123
124
125
N3.6 FUEL
LOW SULFUR
N0.6 FUEL .
LOW SULFUR
N0.6 FUEL
NED. SULFUR
N0.6 FUEL
2.9% SULFUR
DOMESTIC
PRODUCT
N3.6 FUEL
HIGH SULFUR
NO. 6 FUEL
HEAVY
ND. 6 BUNKER
BUNKER FUEL
BUNKER C
RESIDUAL
ARABIAN LIGHT
CRUDE
ARABIAN,
SAFANTVA
HEAVY CRUDE
CALIFORNIA,
KERN RIVER
CRUDE
CALIFORNIA,
WILMIN3TON
CRUDE
IRANIAN HEAVY
CRUDE
418
420
421
417
416
417
363
415
417
418
417
363
363
363
310,330,348(SH) ,356 286
381(SH), 406,448,476,
492(SH), 505,515 (SH)
312,328,366,383, 249
408(SH),447,476,492(SH)
505,516
312,328,365,383 254
408(SH), 448,477,492
505,516
314 (SH) ,366 (SH) ,382 219
430(SH),447,463,492(SH)
505,516
315 (SH), 329,347 (SH) 232
362,381, 410 (SH), 430,
447,463(SH),482(SH)
505,516
316(SH), 329,384, 222
409 (SH), 447, 476
492(SH),506,516
316, 334 (SH), 381, 398, 227
418,446(SH),476,
491 (SH), 505,516 (SH)
314(SH), 345,360,381 222
409, 430,446, 463, 492(SH)
505,516
314(SH),368(SH),383 216
447, 462(SH), 477,492
505,516 (SH)
310,329,364,383 271
408(SH) ,448,476,492(SH)
505,516
311,330,366,383 251
408(SH),447(SH),476
492,505,516
314,334(SH),382 242
404(SH),417,447,492(SH)
505,516
315,331(SH) ,382,418 231
447,492(SH),505,516(SH)
312,330,382,417,447 258
492,505,516 (SH)
(2),
Excited at 230 m
SITE REMEDIATION TECHNIQUES 373
-------
TABLE 2 (oon't.)
LAB NO. TYPE
WAVELENOTH (m) WAVELENGTH (nm)
PRIMARY PEAK SECOMARy PEAKS,
( ±J m) SHOULDERS (SH)
( ±1 n»>
NQfMAUZED
AREA
126
127
128
129
NORTH SLOPE 360
ALASKA CRUDE
PRUDHOe BAY 360
CRUDE
SOUTH 312
LOUISIANA
CRUDE
WYOMIN3 327
CRUDE
r A X - 2Srn
313,328,381 (SH),
401(SH),417,446(SH),
492(SH),505,516(SH)
312,328,382(SH)
401 (SH), 417,446 (SH),
492
T3
I
CO
E
280
440
600
Wavelength (nm)
Figure 2
Emission spectra of a No. 6 fuel oil, low sulfur, Lab No, 113
(solid line ), and a No. 6 fuel oil, Lab No. 110 (dashed line --).
Both 20 /ig/g in cyclohexane. Excited at 254 nm. Excitation bandpass,
4.5 nm. Emission bandpass, 0.9 nm. Backgrounds subtracted out.
374 SITE REMEDIATION TECHNIQUES
(0
e:
I
(0
O
280
440
Wavelength (nm)
Figure 3
Emission spectra of South Louisiana Crude (solid line ), and
Prudhoe Bay Crude (dashed line —). Both 20 pg/g in cydobenne.
Excited at 254 nm. Excitation bandpass, 4.5 nm. Emission
bandpass, 0.9 nm. Backgrounds subtracted out.
m
O
To
O
275
450
Wavelength (nm)
Figure 4
Synchronous spectra of a No. 2 fuel oil, Lab No. 106 (solid line ),
and a No. 6 fuel oil. Lab No. 109 (dashed line—). Both 20 pg/g in
cyclohexane. Both monochromators were scanned simultaneously with
a A X of 25 nm. Excitation bandpass, 4.5 nm. Emission
bandpass, 0.9 nm. Backgrounds subtracted out.
uses spectra of weathered and unweathered oils considered as n-
dimensional vectors in hyperspace (where n is the number of dig-
itized points). These spectra then can be used to generate a
weathering surface in hyperspace, and angles between vectors can
be calculated to estimate weathering effects.
In this paper, an approach similar to the one discussed in the
Pattern Recognition section is used to determine if an unknown
oil belongs to the same class as a known reference oil. As seen in
Tables 3 and 4, 0 - 0.0 is equivalent to identity. Allowing for
weathering effects, experimental error and computer rounding
error, spectra within 8 = 0.005 might still represent the same oil.
Oils of the same class might reasonably be expected to agree to
within 0.15. Table 3 shows the search of a No. 2 fuel oil against
the entire emission library. The similarity between No. 2 fuels oils
and diesel fuels can readily be seen. In some cases it may be neces-
sary to include the wavelength of the maximum peak and the peak
-------
w
c
0
•o
3
rt
E
0
z
450
625
Wavelength (nm)
Figure 5
Synchronous spectra of a No. 6 fuel oil, low sulfur, Lab No. 113
(solid line ), and a No. 6 fuel oil, Lab No. 110 (dashed line —).
Both 20 /tg/g in cyclohexane. Both monochromators scanned
simultaneously with a A X of 25 nm. Excitation bandpass, 4.5 nm.
Emission bandpass, 0.9 nm. Backgrounds subtracted out.
n
c
0)
•o
0)
_N
0
z
625
Wavelength (nm)
Figure 6
Synchronous spectra of South Louisiana Crude (solid line .
_), and
Prudhoe Bay Crude (dashed line —). Both were 20 /tg/g in cyclohexane.
Both monochromators were scanned simultaneously with a A X of 25 nm.
Excitation bandpass, 4.5 nm. Emission bandpass, 0.9 nm.
Backgrounds subtracted out.
area. As indicated in Table 4, it may be necessary to include the
angles between the synchronous spectra to more readily distin-
guish between No. 6 fuel oils and crude oils. Table 5 shows the re-
sults of a library search using the spectrum of a real world sam-
ple (Fig. 10) and the degree of match with reference oil spectra.
Fluorescence/Luminescence-Hazardous
Chemicals Including PCPs
A 1979 U.S. Coast Guard report by Brownrigg, et a/.," listed
approximately 90 hazardous chemicals from the U.S. EPA HSL
list and the U.S. DOT CHRIS list which could be readily iden-
tified by their room temperature fluorescence spectra (now the
basis for a draft ASTM method). By including low temperature
luminescence/phosphorescence spectra, this list could be ex-
tended to include approximately 250 hazardous-chemicals.
Sogliero and Eastwood7'8 used pattern recognition techniques
Table 3
Computer Search of Emission Spectrum of No. 2 Fuel Oil
(Lab No. 107) Against Emission Library (5 Best Matches)
LAB NO.
107
103
106
104
102
TYPE
NO. 2 FUEL
DIESEL FUEL
N0.2 FUEL
DIESEL FUEL
DIESEL FUEL
MAX PEAK(nm)
( ±1 nra)
308
311
308
307
314
NORMALIZED
AREA
102
116
101
97.4
96.4
ANGUIAR*
DISTANCE
(RADIANS)
0.0000
0.0954
0.0964
0.1099
0.1430
*160 DIMENSIONAL VECTOR
Table 4
Comparison of Searches Between Emission (Table 1) and
Synchronous (Table 2) Libraries, for Kern River, California Crude Oil
(5 Best Matches)
EMISSION
LAB NO.
123
TYPE
CALIFORNIA
KERN RIVER
MAX PEAK(nm)
( ±1 nm)
356
CRUDE
NORMALIZED
AREA
222
ANGULAR11'
DISTANCE
(RADIANS)
0.0008(2)
118
124
109
110
NO. 6 BUNKER
CALIFORNIA
WILMINGTON CRUDE
N0.6 FUEL OIL
1O.6 FUEL OIL
359
357
358
357
212
211
233
218
0.0482
0.0708
0.0754
0.0841
SYNCHRON3DS
LAB NO.
123
TYPE MAX
CALIFORNIA
KERN RIVER CRUDE
PEAK(nm)
( ±J. nm)
363
NORMALIZED
AREA
242
ANGULAR13'
DISTANCE
(RADIANS)
o.ooos'21
118
124
125
127
(1)
(2)
(3)
NO.6 BUNKER 363
CALIFORNIA 363
WILMINGTON CRUDE
IRANIAN 363
HEAVY CRUDE
PRUDHOE BAY 360
CRUDE
160 Dimensional Vector
227
231
258
254
0.0478
0.0619
0.0722
0.1958
Note computer rounding error
175 Dimensional Vector
and similarity measures such as angle between spectra as n-dimen-
sional vectors in hyperspace, Euclidean distances and correla-
tion coefficient on a library of about 60 low temperature lumi-
nescence spectra of hazardous chemicals.
Earlier work by Brownrigg and Hornig" showed that low
temperature luminescence spectra could distinguish PCBs from
DDT. In this study, only PCBs (Aroclors® ) have been used as
an example of hazardous chemicals for which fluorescence/lum-
inescence techniques should be useful. Fig. 11 shows a compari-
son of PCBs at 77 °K where the emission intensity is greater for
phosphorescence than fluorescence so that greater sensitivity
(allowing quantitation to a few ppb) is achieved using low
temperature luminescence. For field screening at the ppm range,
SITE REMEDIATION TECHNIQUES 375
-------
CO
c
-------
II)
c
0)
•o
3
rt
E
0
z
Tables
440
Wavelength (nm)
Figure 11
Low temperature (77 K) luminescence spectra showing both
fluorescence and phosphorescence of Aroclor® 1221,10/tg/g
(solid line ), and Aroclor® 1254, 27 /tg/g (dashed line
Both in methylcyclohexane. Excited at 270 nm. Excitation
bandpass, 4.5 nm. Emission bandpass, 0.9 nm. Blank in spectra
indicates where second order emission has been deleted.
600
(0
Q)
TJ
ffl
N
ffl
0
Z
390
500
Wavelength (nm)
Figure 12
Emission spectra of a real world sample extracted from soil with
cyclohexane and H2SO4 (solid line ), and Aroclor® 1254,
27 /(g/g in cyclohexane (dashed line —). Excited at 270 nm. Excitation
bandpass, 4.5 nm. Emission bandpass, 0.9 nm. Backgrounds
subtracted out.
sites, they usually were unnecessary.
Two examples of typical FT-IR oil spectra are included. Fig. 13
compares the FT-IR spectra of No. 2 and No. 6 fuel oil from
2000 - 500 cm-'. Note that the 900-700 cm-' region, the so-
called fingerprint region, has been particularly indicative of oil
type and relatively unchanging with weathering. Fig. 14 compares
similar reference spectra for a Prudhoe Bay crude oil and a South
Louisiana crude oil. Earlier studies by Brown and others27"34
have addressed likely changes in reference spectra (peak positions
and peak ratios) due to weathering and have proposed artificial
weathering or knowledge of the weathering history for similar oils
as a method of compensating for these effects.
In Table 6, peak positions for the oils in Fig. 13 and 14 are
listed for the peaks previously selected by Brown and others27'34
Against Emission Library (5 Best Matches)
LAB NO.
127
126
121
125
114
TYPE
REAL WORLD SAMPLE 343
pRUDHoe BAY am
NORTH SLOPE ALASKA CKEE
ARABIAN LIGHT CRUDE
IRANIAN HEAVY OODB
NO. 6 FUEL KBDXOI SOUDR
MAXFEM(m)
(ilm)
357
357
357
35C
358
35C
NQfHALIIED
AREA
209
212
193
231
217
232
ANGULAR*
DISTANCZ
(RADIANS)
0.0764
0.0903
0.0931
0.1045
0.1131
•160 DIMENSIONAL VECTOR
Table*
List of Wavenumbera Used in Computer Analysis of Infrared Spectra
(To Nearest 5 CM-1)
720
725
745
765
770
780
790
60S
810
820
835
845
870
8M
955
1020
1070
1145
1160
Table 7
Aromatic-Aliphatic Peak Intensity Ratios for Infrared Peaks
747CM->and725CM->
LAB NO.
WPB
AKMUIGftUHUIC BMCID*
106 N0.2 FUEL 1.33
110 N0.6 FUEL 1.44
127 PRUDBOB BAY OBDB 1.07
128 SOOTH LOOISIMR CMB 0.737
•Peak at 747 on, oarMpanda to 0-0 aranaUc
Peak at 725 of* CDmepONls to OH aliphatic
Tables
Computer Search of FT-IR Spectra of Prudhoe Bay Crude Against
Typical Oil Types
LAB NO.
mmmm DISTANCE
(RHOMB)
(1)
127 PHJDHOE BKXCMXB
106 N0.2 KIEL
110 N0.6 FUEL
128 SOUTH LOUISIMA CUJDB
0.0010*2'
0.1819
0.1997
0.3551
(1)
(2)
20 DIMENSION. VECTOR
NOTE COMPUTER HOUNDING ERROR
SITE REMEDIATION TECHNIQUES 377
-------
1600
Wavenumbar8(cm~')
Figure 13
FT-IR spectra of No. 2 and No. 6 fuel oils. Resolution was 2 cm ~' with
64 scans. KBr windows with a 0.05 mm Teflon spacer were used.
1900
Wavenumbersfcnr1)
Figure 14
FT-IR spectra of Prudhoe Bay and South Louisiana Crudes.
Resolution was 2 cm -' with 64 scans. KBr windows with a 0.05
Teflon spacer were used.
as useful for oil identification by infrared. In Table 7, the ratio of
747 cm"17725 cm"' gives a comparison of the aromatic/aliphatic
composition. This is of interest primarily for comparison to the
fluorescence spectra which characterizes the aromatic fraction of
the oil or fluorescent hazardous chemicals containing aromatic or
heterocyclic ring systems.
For pattern recognition purposes, the greater spectral structure
and greater ease in infrared interpretation of infrared peaks in
terms of vibrations of known structural components (group fre-
quencies) plus the large infrared libraries of hazardous chem-
icals available make more elaborate pattern recognition schemes
relatively unnecessary. Although spectral areas and angles be-
tween n-dimensional vectors can be given, they are needed less for
classification purposes than in the case of fluorescence. The use
of oil classification by angles between spectral vectors is illus-
trated in Table 8.
CONCLUSIONS
Fluorescence/luminescence spectroscopy has been used suc-
cessfully for screening, detecting, classifying and semiquanti-
tating real world DOD samples containing petroleum oils, petrol-
eum-based fuels and solvents and PCBs in a variety of sample
matrices (water, soil, sludge and bulk chemicals). By supplement-
ing fluorescence techniques with FT-IR, where necessary, for con-
firmation and to detect non-aromatic or non-fluorescing com-
ponents, these complementary techniques can form a powerful
analytical tool for screening and classifying hazardous chemicals
in a variety of environmental wastes. These techniques poten-
tially can be applied to a broader range of hazardous chemicals
under field conditions.
Appropriate in-house reference libraries of petroleum oils are
being developed. Pattern recognition techniques for both fluores-
cence and FT-IR spectra have been developed. For fluorescence
(emission and synchronous), useful parameters included maxi-
mum peak positions, areas under the spectral envelope of the
normalized spectra and angles between appropriate spectra where
spectra are treated as n-dimensional vectors. For FT-IR, pat-
tern recognition techniques included peak positions (for 20 major
peaks), a peak ratio to indicate the aromatic/aliphatic character
of the oil and angles between spectra treated as 20-dimensional
vectors.
In the future, we plan to expand spectral libraries for reference
petroleum oils and fuels and hazardous chemicals analyzed on
in-house instrumentation by both fluorescence and FT-IR. A bet-
ter classification scheme for oil spectra including subclasses based
on spectral characteristics rather than just API categories or
physical properties could be developed. Classification schemes re-
lated to the geographical origin of oils also may be of interest.
Different chemometric or pattern recognition approaches may
be applied, including use of similarity measures such as correla-
tion coefficients or Euclidean distances, Fourier transformations
or sine and cosine series.
Preliminary measurements on PCBs need to be expanded and
refined to allow better detection, identification and quantitation
of these ubiquitous chemicals even in the presence of oils. Studies
of other important classes of fluorescing hazardous chemicals
such as phenols, organochJorine pesticides, dioxins and PNAs are
needed.
Better quantitation procedures for oils by fluorescence are
needed. Better field procedures are required, especially for PCBs,
pesticides and DDT. Exploration of techniques such as room
temperature phosphorescence and remote fiber optics also are
planned.
ACKNOWLEDGEMENTS
The authors wish to acknowledge the U.S. EPA (EMSL-Cin-
cinnati), Oak Ridge National Laboratory (W. Griest) and the
U.S. Coast Guard Research and Development Center (M. Hend-
rick) for providing reference oils and fuels. They wish to thank
J. Winters for assistance with manuscript preparation. In particu-
lar they wish to acknowledge R. Schlenker and J. Solsky for gen-
eral administrative and laboratory support and T. Killeen and
C. Brown for useful discussions.
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378 SITE REMEDIATION TECHNIQUES
-------
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13. Giering, L.P. and Hornig, A.W., Am. Lab. 9, 1977,113.
14. John, P. and Soutar, I., Anal. Chem., 48, 1976, 520.
15. John, P. and Soutar, I., Proc. Anal. Div. Chem. Soc., 13, 1976, 309.
16. Kerkhoff, M.J., Files, L.A. and Winefordner, J.C., "Identifica-
tion of Polyaromatic Hydrocarbon Mixtures by Low-Temperature
Constant Energy Synchronous Fluorescence Spectrometry," Anal.
Chem., 57,1985,1673.
17. Lloyd, J.B.F., Analyst, 99,1974, 729.
18. Lloyd, J.B.F., /. Forens, Sci. Soc., 11, 1971, 83, 135, 153.
19. Neal, S.L., Patonay, G., Thomas, M.P. and Warner, I.M., "Data
Analysis in Multidimensional Luminescence Spectroscopy," Spectro-
scopy, 1, 1985,22.
20. Vo-Dihn, T., "Room Temperature Phosphorimetry for Chemical
Analysis," Health and Safety Research Division of Oak Ridge Na-
tional Laboratory, 1984.
21. Berlman, I.E., Handbook of Fluorescence Spectra of Aromatic
Molecules, 2nd ed., Academic Press, New York, NY, 1971.
22. Brownrigg, T.J., Busch, D.A. and Giering, L.P., "A Luminescence
Survey of Hazardous Materials," Report No. DOT-CG-D-53-79,
May 1979.
23. Miller, T.C. and Faulkner, L.R., "Computer Assisted Structural
Interpretation of Fluorescence Spectra," Anal. Chem., 48, 1976,
2083.
24. Parker, C.A., Photoluminescence of Solutions, Elsevier, New York,
NY, 1968.
25. Schulman, S.G., Molecular Luminescence Spectroscopy: Methods
and Applications: Part 1, Wiley-Interscience, New York, NY, 1985.
26. Yim, K.W.H., Miller, T.C. and Faulkner, L.R., "Chemical Char-
acterization via Fluorescence Spectral Files: Data Compression by
Fourier Transformation,'Mna/. Chem., 49,1977,2069.
27. Ahmadjian, M., Baer, C.D., Lynch, P.P. and Brown, C.W., "In-
frared Spectra of Petroleum Weathered Naturally and Under
Simulated Conditions," Environ. Sci. Tech., 10, 1976, 777.
28. Brown, C.W., Lynch, P.P., Ahmadjian, M. and Baer, C.D.,
"Weathered Petroleum: Advantages of Using Infrared Spectroscopy
for Identification," Am. Lab., Dec. 1975, 59.
29. Brown, C.W., Lynch, P.P. and Ahmadjian, M., "Chemical Analy-
sis of Dispersed Oil in the Water Column," Chemical Dispersants
for the Control of Oil Spills, 1978,188.
30. Brown, C.W., Lynch, P.P. and Ahmadjian, M., "Monitoring
Narragansett Bay Oil Spills By Infrared Spectroscopy," Environ.
Sci. Tech., 8, 1974,669.
31. Brown, C.W., Lynch, P.F. and Ahmadjian, M., "Feats of Magic,"
Ind. Res. Dev., May 1978,122.
32. Lynch, P.F. and Brown, C.W., "Identifying Source of Petroleum
By Infrared Spectroscopy,"Environ. Sci. Tech., 7,1973,1123.
33. Lynch, P.P., Tang, Sheng-Yuh and Brown, C.W., "Application of
Cryogenic Infrared Spectrometry to the Identification of Petrol-
eum," Anal. Chem., 47, 1975, 1696.
34. Anderson, C.P., Killeen, T.J., Taft, J.B. and Bentz, A.P., "Im-
proved Identification of Spilled Oils by Infrared Spectroscopy,"
Environ. Sci. Tech., 14, 1980,1230.
35. Brown, C.W., "Multicomponent Analysis Using P-Matrix
Methods,"ASTM, 12, 1984, 86.
36. Griffiths, P.R. and De Haseth, J.A., Fourier Transform Infrared
Spectrometry, Wiley-Interscience, New York, NY, 1986.
37. Puskar, M.A., Levine, S.P. and Lowry, S.R., "Computerized
Infrared Spectral Identification of Compounds Frequently Found at
Hazardous Waste Sites," Anal. Chem., 58, 1986,1156.
38. Gurka, D.F., Project Summary, "Interim Protocol for the Auto-
mated Analysis of Semivolatile Organic Compounds by Gas Chrom-
atography/Fourier Transform Infrared (GC/FT-IR) Spectrometry,"
EPA-600/S4-84-081, Dec. 1984.
39. Chien, Y.T. and Killeen, T.J., "Computer and Statistical Consider-
ations for Oil Spill Identification" in Handbook of Statistics vol. 2,
Krishnaiah, P.R. and Kanal, L.N., eds., North Holland Publishing
Co., New York, NY, 1982, 651-671.
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Recognition, Wiley-Interscience, New York, NY, 1975.
SITE REMEDIATION TECHNIQUES 379
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Toxic Gas Collection and Treatment System
At an Uncontrolled Superfund Site
Win. Edward McCracken, Ph.D., P.E.
S & D Engineering Services, Inc.
Metuchen, New Jersey
David R. Henderson
New Jersey Department of Environmental Protection
Trenton, New Jersey
ABSTRACT
A toxic gas collection and treatment system was installed on an
emergency basis at the uncontrolled landfill Superfund site in
Gloucester Township, New Jersey. Monitoring at the site indi-
cated that a mixture of combustible and toxic gases was moving
toward two residential areas built near the toe of the landfill. The
New Jersey Department of Environmental Protection (NJDEP)
became concerned about the combustibility and toxicity of these
gases as they continued to migrate toward the homes. When mon-
itoring data began to indicate combustible levels approaching the
lower explosive limit near the homes, the NJDEP decided that
action should be taken to install a gas collection and treatment
system.
Problems that are presently being resolved include:
• Fail-safe systems to prevent liquids from reaching the blower
• Monitoring exhaust gases from the present treatment unit to
determine if further treatment is necessary.
Toxic dangerous chemicals included methane gas, benzene
compounds, xylene and toluene. Numerous other compounds
were present at lesser levels.
INTRODUCTION
During the period beginning Oct. 22, 1985 and ending Jan. 24,
1986, S&D Engineering Services was engaged in the fabrication,
installation and erection of a gas recovery and treatment system
at the GEMS Superfund site under the direction of the New Jer-
sey Department of Environmental Protection (NJDEP). Upon
completion of the construction phase of the work, S&D Engineer-
ing Services provided operations and maintenance services for
the collection and treatment system as directed by the design en-
gineer and the NJDEP.
The system consists of 32 wellpoints installed in two locations
designated "Site A" and "Site B" and consisting of 14 and 18
wells, respectively. The wells are connected by 8-in. schedule 40
PVC piping designated "Header A" and "Header B", respec-
tively. A 10-in. PVC pipeline extends from the treatment plant to
header B and connects it to the system. A 2000 ftVmin positive
displacement pump is connected to the system which draws the
gas and air mix from the soil and groundwater and passes it
through an activated carbon treatment system and thereafter out
through a 20-ft high exhaust stack.
PROBLEM DESCRIPTION
The Gloucester Environmental Management Services (GEMS)
Landfill had operated for more than 20 yr. Prior to 1974, organic
solvents and other industrial chemicals were disposed of in areas
below the groundwater table. Preliminary geophysical investiga-
380 SITE REMEDIATION TECHNIQUES
lions conducted by the Department's Division of Water Re-
sources indicated that the landfill is the cause of surface and
groundwater contamination. Volatile organic chemicals have
been detected in monitoring wells, private wells, leachate and
stream samples.
The GEMS Landfill is located in Gloucester Township, New
Jersey. The residences closest to the landfill are in two small
developments off Enal Road; namely Fox Chase II and Holly
Run Road (see Fig. 1). Holly Run is a small stream that is lo-
cated between these residences and the landfill. The site has been
studied by the NJDEP, the U.S. EPA Technical Assistance Team
(TAT) and the NUS corporation.
Much of the previous investigation of the site has focused on
groundwater. However, this work addressed the soil-to-air emis-
sions and the migration of hazardous gases through the soil and
the groundwater.
Previous studies identified some of the organic gases in the
soil. The principal gas is methane which is generated through
municipal decomposition; however, volatile organic compounds
(VOCs) also were found in the gas phase in the soil.'
Samples were taken in the general vicinity of the residential
housing developments. The data show significant concentrations
of gases in the area between Fox Chase II and the landfill. Levels
ranged up to lOO^o Lower Explosive Limit (LEL). VOCs were
found in the gas from these areas at concentrations of 1.0 to
48.6 ppm. Neither methane gas nor VOCs were detected north of
Erial Road. In the remaining areas investigated, levels of organics
were not as high and dropped off rapidly as the distance from
the landfill increased. As a result of these findings, remedial
measures were developed to reduce gas migration from the land-
fill.
Compounds found in the ambient air at the site include
toluene, benzene, ethylbenzene, chlorobenzene and xylenes.
Some of the highest concentrations were found along Erial Road
and along Holly Run.
Soil gases were measured by extending a borehole about 4 ft in-
to the ground and sampling the borehole air. Contaminants
found in the soil gas samples included 1,2-transdichloroethene,
trichloroethene, xylene, benzene, toluene, ethylbenzene, chloro-
benzene and styrene. Details of these data are available in other
reports.1'2
The conclusions from both of these previous investigations that
are most relevant to the emergency situation are:
• Methane gas contaminated with volatile organics was migrating
from the landfill face parallel to Erial Road in the vicinity of
the Holly Run Road residences in concentrations greater than
100% of the LEL. Volatiles were detected at 49 ppm.
• Methane gas contaminated with volatile organics was migrating
-------
from the landfill face parallel to Erial Road in the vicinity of
Fox Chase II development in concentrations exceeding 100% of
the LEL. Analysis of the soil gas from the backyard of one of
the residences confirmed the presence of methane gas migrating
from the landfill.
• The residential area between Holly Run Road and the intersec-
tion of Erial Road and Hickstown Road was the site of one
sample, and this showed no detectable levels of either methane
gas or volatile organic compounds.
It was evident that methane gas existed in the area at concen-
trations greater than the LEL. While not usually a hazard in the
soil, under certain atmospheric conditions this gas could create an
explosive mixture if allowed to accumulate in a confined space
such as a basement. This gas was contaminated with detectable
and significant quantities of volatile organic compounds com-
posed primarily of benzene, toluene and ethylbenzene, with less-
er amounts of chlorobenzene and dichlorobenzene.
It was the opinion of the NJDEP that there may be an explo-
sion hazard to the residences of the Fox Chase II development
and those on Holly Run Road but not to those north of Erial
Road. This situation presented a health and safety risk to those
on-site and near the site in the areas of concern.
REMEDIAL ALTERNATIVES
As a result of these findings, two remedial actions that ad-
dressed gas controls for hazard elimination at the affected resi-
dences were considered.2 These were:
• Induced draft pipe vents with a collection system and gas treat-
ment system
• Induced draft closed trench vent with an integral collection sys-
tem and gas treatment system
Induced Draft Pipes
An induced draft pipe vent collection system consists of four
main parts:
• Pipe vents in and/or around landfill surface
• Collection system with fittings and balancing valves
• Fan or blower to provide driving force on vents
• Pressure Measuring device before and/or after the fan or
blower
In addition, provisions for moisture collection, access ports
and allowances for differential settlement of the header pipe sys-
tem need to be considered and incorporated into the design of the
system. The vent pipes are installed at appropriate intervals de-
pendent upon subsurface soil conditions to collect all gas and not
allow any migration past the vent line. The vent is usually about 4
to 8 in. in diameter and is surrounded by a Iwyer of coarse gravel.
The total diameter of the installation may vary up to 3 ft. The sur-
face in the immediate vicinity of the vent is capped with impervi-
ous material to prevent rainwater infiltration and unwanted gas
venting.
The vents are connected to an exhaust header which may be a
single branch or one of a number of branches connected to a man-
ifold and ultimately to a fan or blower that puts a negative pres-
sure on the vent and draws out the gas. Each connection to the
vent is supplied with a measuring device such as a pilot tube and/
or a control device such as a butterfly valve for balancing the sys-
tem.
The final part of the vent system includes equipment for the
treatment and disposal of the collected gas. The two primary
treatment methods used are carbon adsorption and thermal oxi-
dation. Given the high concentrations of VOCs found in the gas
from the GEMS Landfill, it probably will be necessary to treat the
gas by passing it through a carbon chamber prior to venting or
flaring. The carbon scrubs the higher molecular weight volatiles
from the gas stream while leaving the methane intact for subse-
quent venting or flaring.
Induced Draft Trench
An induced draft closed trench collection system utilizes a hori-
zontal collection pipe in a continuous trench excavated down to
either ground water or an impervious layer. The trench is lined
with a synthetic liner to eliminate gas migration and is filled with
gravel to facilitate gas movement toward the collection pipe bur-
ied in the trench. This collection pipe is connected to a blower or
fan for gas collection. The gas is treated and discharged in a sim-
ilar fashion to the pipe vent system.
System Choice
These two alternatives were evaluated based on five criteria:
Reliability
Constructibility
Implementation time frame
Environmental effectiveness
Cost
The pipe vent collection system scored the highest in the evalua-
tion and was the alternative of choice for perimeter control of
gas.2 The gas vent specification is shown in Fig. 3; the final re-
medial design installed at the site is shown in Fig. 1 and 2.
THE EMERGENCY INSTALLATION
NJDEP Action
After evaluating the environmental and health concerns at the
site, the NJDEP decided an emergency response was necessary.
The main object was to prevent the combustible and toxic mixed
gases from continuing to migrate toward the two residential areas.
New Jersey has several sources of funds to be used for remed-
ial work at Superfund sites. These are:
• The Spill Compensation Fund—$25,000
• The Hazardous Discharge Bond Act—$100,000
• The Superfund Allocation for New Jersey—$84,000
In this case, the Emergency Spill Fund was used.
A Project Officer was designated by the state. His responsibil-
ity was to select the best remedial alternative within the time and
cost constraints given and select a contractor who could install the
system on an emergency basis. The major constraints in descend-
ing order were:
• Protection of health and environment from the migrating gases
• Time—selection of remedial design and the installation of the
system was on an emergency basis
• Cost—the emergency basis was inherently expensive, but cost
savings were considered each step of the way
• Operation and maintenance—the system had to operate unat-
tended with a minimum of maintenance
Consultant's Actions
S & DESI was called on Oct. 10,1985 (because it was at the top
of a rotational list of qualified emergency contractors for the
Southern Region of the state) and was told that a gas collection
system needed to be installed at the site on an emergency basis.
However, a planning meeting was required to discuss the pro-
posed design and how to implement it at the site. A result of this
meeting was that the gas collection system was changed from a
trench design to a collection well design. Both designs were de-
scribed in the preceding section.
The main reason for changing the design was to minimize the
risk of a release of explosive/toxic gases and the associated poten-
SITE REMEDIATION TECHNIQUES 381
-------
tial hazards. Installing one 6-in. diameter gas collection well at a
time minimized both the risk of gas release and hazardous inci-
dent.
Health and Safety
Health and safety guidelines were established to protect both
the workers and nearby residents. The main concerns were the
potential releases of toxic gases above the Permissible Exposure
Limit (PEL) and release of explosive gases above or near the
LEL. The action level for initiating ambient gas monitoring of
nearby homes for sustained levels of methane and other explosive
gases was 25% of the LEL. The action level for upgrading the
personal protection level was a sustained level of the toxic volatile
organics of 5 ppm or the lowest PEL, whichever was determined
to be lower.
On-site monitoring during the installation included the follow-
ing:
• A meteorologic weather station was installed to daily record
wind direction, speed, temperature and humidity
• A photoinization detector was calibrated and used to monitor
for the listed volatile organics
• Explosimeters were used to monitor both methane gas and total
mixed explosive gases
• Packed sampling tubes with calibrated pumps were used to ob-
tain 7-hr samples for GC/MS analysis as required
• The ANJDEP Air Monitoring team used a PID and OVA
(portable gas chromatograph) to periodically (approximately
once per week) monitor in the work zone and near the residen-
tial homes
The on-site health and safety plan included an air monitoring
survey using a PID; this survey was conducted prior to the com-
mencement of work each morning. The readings found in the sur-
vey were used to determine the level of personal protective equip-
ment to use and to confirm the level of protection needed at the
various areas/zones at the site.
The NJDEP required that all personnel have medical monitor-
ing prior to working at the site. This requirement was used to
determine whether the worker (1) was physically fit for the job
and could wear respirators and (2) had an existing physiological
problem due to previous exposure to the types of contaminants
at the site.
Contingency and emergency evaluation plans were developed
for the project. The most critical safety planning elements for
this site concerned what to do if explosive gases levels approached
the LEL and/or toxic gas levels exceeded their PEL. Local emer-
gency resources were contacted and included in the plan. Emer-
gency response gear maintained at the site and near the work
zones during operations included:
• SCBAs for respiratory protection
• Several class A, B, C Fire Extinguishers
• Several protein foam canisters and applicators for vapor sup-
pression
• A portable fire pump and fire hose with long-range nozzle
• Earth-moving equipment with enclosed cabs and SCBAs to
provide emergency earth coverage
The major health and safety problems encountered at the site
were:
• The roadway constructed between Sites A and B involved a
considerable amount of uncertainty; therefore operations were
conducted in Level B protection; additional concerns were
raised by several buried drums that required special cleanup
and security
• The recovery well installation at Site B required a considerable
amount of Level B protection and portable communication
since it was approximately 3,000 ft from Site A and the office
trailer
• Several workers received temporary medical treatment for nau-
sea due to the inhalation of normal "garbage" odors associated
with most domestic landfills: methane and other toxic gases
were not detectable even with an 8-hr sample analyzed with a
GC/MS. We went to Level B protection for additional safety
in this work area
PROBLEMS AND SOLUTIONS
Specific Problems
Difficult problems that were overcome during the installation
included:
• Installing collection wells rapidly in unconsolidated materials
with a near-surface groundwater table
• Maintaining a slope on the collection manifold to drain off
condensate and leachate
• Allowing for collection pipe movement due to thermal effect
and soils movement
• Connecting two gas collection systems located approximately
3,000 ft apart through rough terrain, forest, marsh and landfill
areas
• Contending with buried drums and other hazardous waste
• Preventing possible gas ignition from occurring and moving
through the system
Specific Solutions
The overall assessment of the installation project was that it
was very successful. Each problem listed above was overcome.
S & D Engineering Services, Inc. developed a recovery well in-
stallation technique using a large truck mounted backhoe, a front
end loader and a 12-in. diameter by 25-ft long steep pipe with a
4-ft lift cable attached to one end. The backhoe dug a pit rough-
ly 4 ft in diameter and 15 ft deep in the unconsolidated/unstable
soils. This pit normally went at least 4 ft into the existing ground-
water table. The steel pipe was quickly attached to the backhoe
and lowered into the pit to prevent the soil from caving in. The
6-in. diameter slotted/screened PVC pipe was then installed in-
side the steel casing, and river gravel was packed around it using
the loader and shovels. The soil was then packed around the out-
side of the casing and the casing was lifted vertically and removed.
Using this method, up to 8 wells could be installed per day, bar-
ring unforeseen difficulties.
Much of the excavation for access roads and well installations
was into parts of the landfill. This created some unpredictable
health and safety problems that had to be solved. The same safety
procedures stated for the general well installation technique were
used here, also. In addition, an emergency response vehicle with
spill response materials and drum handling capability was put on
standby while working in the landfill areas per se. This response
capability was used on several occasions.
One of the biggest obstacles to the completion of this project
was how to connect two gas collection systems locateld approx-
imately 3000 ft apart, through rough, forested terrain. The con-
necting line was to have constant slope from system B down to
the system A connecting points and a minimum pressure loss.
This line was successfully achieved by using 8-in. diameter PVC
pipe, heavy equipment and chain saws to clear the trees and thick-
ets and wooden mounts to elevate the pipeline and maintain the
slope. With the manifold pipelines and the common collection
point, all water could be drained out of the lines prior to reaching
the blower.
Thermal effects on the above-ground system also were consid-
ered. The effects of thermal expansions and contractions
382 SITE REMEDIATION TECHNIQUES
-------
throughout the thousands of feet of welded PVC pipes were re-
lieved by using rubber-base connectors (Fernco® connectors).
These connectors also allowed flexibility in routing the pipeline
through the marshy woods and adjusting for elevations. Also,
the vertical gas collection wells were connected to the horizontal
manifold pipeline using wire reinforced rubber pipe connectors
for both systems A and B.
Several potential sources of ignition were defined in the gas
treat system which consisted of a gas blower (or pump) and a
granulated activated carbon (GAC) unit. The gas blower was re-
quired to deliver 2000 ftVmin at 24 in. of water column pres-
sure. However, the blower had to be an "off-the-shelf" unit
since the installation was on an emergency basis. To get a unit
that was non-ferrous and internally explosion-proof for the gases
involved would have taken several months. So the glas blower be-
came a potential source of gas ignition. The supplier of the GAC
unit indicated that static electricity could build up and possibly
ignite the gases at their LEL. To eliminate the possibility of ig-
nited gases cascading throughout the entire system, a flame arres-
tor was placed both upstream and downstream of the gas blower.
Project Startup
After the installation was completed and the blower was in-
stalled and checked out electrically, the equipment was tested.
Startup procedures were carefully adhered to, especially with
the blower. This included operating the unit under the no load
condition for the specified period of time.
Having completed all shakedown requirements and initial
startup procedures, the gas collection/treatment system was
ready for commissioning. Since there was no way to be sure about
the pressure drops throughout each system, we decided to open
the butterfly valves to each well and the main control valve for
the interconnecting line to system B only 50%. The three air inlet
valves (one at each end of manifold A and one at the extremity
of manifold B) were left closed. The blower was started and
vacuum pressures were measured at selected wells for system A
and B and the pressure drop across the blower. The Positive Dis-
placement type blower generated much more vacuum than re-
quired at the wells, and the systems were not balanced. After con-
siderable trial and error, the valves were adjusted to effect nearly
the same vacuum in each well, and the air inlet valves were opened
to allow a general lowering of the vacuum throughout the entire
system.
Water Problems
Once the system was balanced and running well, we decided to
let it run continuously for 24 hr. During this period, we discov-
ered that the varying water table could have a drastic effect on
the system as the level of groundwater rose to cover the slotted/
screened portions of the gas recovery wells. When this occurred,
the blower would lift the water/leachate out of the well and draw
it into the gas blower. The blower, not being designed for liq-
uids, became overloaded and shut down. Fortunately, the blower
was repairable and all moisture and impending rust were re-
moved. The blower has been installed in a standby mode until the
system is modified to eliminate/prevent moisture from reaching
the blower.
TREATHIGAS '
SIDF VIFW
TREATED GAS
TOP VIEW
(*•
7
i
> K
«BL£f
xj;
OSE K^yi
_ C> ))
•^
ACCWULATOR CABINET
WITH GAC TFEATIENT UNIT
nz±^
POS1T1NE
DISPLACEMENT
-FUME AWESTCRS
TCKIC
'GASES
SCALE
RADIALLY DISPERSING
GRANULAR ACTIWIED
CARBON (GAC)
TOEATIEJff IHIT
COSTIVE
DISPLACEMENT
BLOWER
2 FT 0
8 IOFT
Figure 1
Toxic Gas Treatment System
SITE REMEDIATION TECHNIQUES 383
-------
* nltKWi • } FCC I
AM AS NO! CO
DO
rf
5CAU
1— I I \ III I.I I I
; oo aa »o «oo wo
Figure 2
Toxic Gas Collection and Treatmeni System
System Uncertainties
Normal procedures for installing a system as complex as this at
an uncontrolled site with its numerous uncertainties would re-
quire a complete and thorough study of all pertinent facts and
design parameters. However, when significant health and en-
vironmental risks are so imminent, there is hardly time to follow
the normal/standard operating procedures. Rather, the question
becomes one of what can be done to alleviate the dangers and
risks within a specified short amount of time. So time becomes
the overriding specification and engineering design and specifica-
tions as well as the environmental information upon which they
are based become supplemental to it. Even with the uncertainties
at hand, a system was installed that had the necessary flexibility to
allow it to operate adequately under continuous supervision and
provide protection to the nearby residents suffering from the
migrating toxic/explosive gases.
FUTURE PLANS
Future plans call for further refinement of the system to allow
it to operate unattended and trouble-free. These planned modifi-
cations include the design and specification of water/moisture
sensors that will be installed at various strategic points through-
out the system to send early warning signals to activate an alarm
and/or shut the blower off. Should the blower be shut off, an
automatic telephone dial system would be activated to place an
emergency call to the NJDEP and/or emergency response con-
tractor. A preprogrammed message would be given to the recip-
ient of the emergency call. Immediate action could be taken to re-
store the system to proper operation.
Figure 3
OEMS Landfill Gas Vent Detail
384 SITE REMEDIATION TECHNIQUES
-------
Also, consideration is being given to using automatic monitors REFERENCES
for the exhaust gas. This monitoring is especially desirable if high j _ UiS> EPA> ..Remedial Investigation Report Volume I for Gloucester
concentrations of methane are encountered. It is fairly certain Environmental Management Services, Inc. (GEMS) Landfill Site,
that the recovered gas concentrations will vary significantly over Camden County, New Jersey," U.S. EPA Work Assignment Num-
extended periods of time. Should significant levels of methane ber 15-2M29.0, July 1985, Chaps. 4 and 5.
continue, the NJDEP will consider the installation of the ground 2. NJ Department of Environmental Protection, "Gas Migration Re-
flare system to burn-off the methane and mixed gases, polrt for GEMS Landfill Gloucester Township, New Jersey," Mal-
colm Pirnie, Oct. 1985.
SITE REMEDIATION TECHNIQUES 385
-------
Rapid, Cost-Effective GC Screening for Chlorinated
Pesticides and Volatile Organics at CERCLA Sites
Richard A. Cheatham
Jeffrey Benson
Jeralyn Guthrie
William Berning
C.C. Johnson & Associates, P.C.
Denver, Colorado
Roger L. Olsen, Ph.D.
Camp Dresser & McKee Inc.
Denver, Colorado
ABSTRACT
The Region VIII REM II Team (CCJA/CDM) has developed
an in-house analytical support program that provides rapid, cost-
effective screening analyses of organic contaminants in en-
vironmental samples. This program has been used to support
RI/FS field activities at a CERCLA site in the Denver metropoli-
tan area. The site manager and the project health and safety of-
ficer have used the screening data in the execution of the follow-
ing activities: site characterization, decontamination procedures,
monitor well screen placement and site personnel exposure
monitoring.
The screening protocol for organic contaminants has been de-
signed to meet project requirements for the semi-qualitative,
semi-quantitative analysis of specific target compounds that have
been identified from previous site work. For this project, the list
of target compounds that are indicative of the classes of chemical
contaminants (e.g., volatiles and chlorinated pesticides) that are
present on-site includes: trichloroethylene, toluene, p,p-DDT and
dieldrin. Additionally, relative amounts of organic contamination
due to the presence of either exiractable or volatile compounds
may be determined. Organic compounds are detected using two
portable HNu 301 gas chromatographs equipped with a PID con-
nected in series with either an FID or a Hall-type ECD (halogen-
mode). Sample preparation techniques include a hexane/acetone
extraction procedure for chlorinated pesticides and either
headspace or purge and trap for volatiles.
Requirements for sample cleanup and preparation are mini-
mized using the halogen-specific detector and the headspace tech-
nique (for volatiles).
The analytical quality assurance program includes standard
operating procedures for the following steps: sample collection
and analysis, personnel training, sample custody, document con-
trol and data management. Laboratory quality control samples
(i.e., blanks, duplicates and matrix spikes) have been analyzed at
a minimum frequency of 1 per 10 samples or 1 per batch. Instru-
ment calibration has been performed daily, and calibration
checks have been performed on a per batch basis. Split samples
have been sent to U.S. EPA Contract Laboratory Program (CLP)
laboratory for analysis at a minimum frequency of 1 per 5 field
samples collected. Split sample data has enforcement-quality
analytical data.
A statistical data summary is presented below for the analysis
of volatile compounds in the low /tg/1 to the mg/I range and of
chlorinated pesticides in the low /ig/1 to the high mg/1 range.
INTRODUCTION
A critical procedure for RI/FS activities conducted under the
CERCLA program is the development of a sampling and analysis
plan that is consistent with CERCLA program objectives and re-
quirements. This plan must address the specific requirements of
individual sites, be based upon the intended use of the data and be
consistent with project constraints such as time and resources.
For example, in order to meet these objectives, the RI/FS pro-
ject discussed in this publication was designed to be implemented
in several phases The two main intended uses of the data for the
RI Phase I are (1) for health and safety and (2) for site
characterization. Data collected for health and safety purposes
typically are used, for example, to establish the level of protection
needed for investigators or workers at a site. Standard practice is
to collect baseline health and safety data, and then to collect data
during site activities that involve disturbing baseline conditions,
e.g., well drilling. Health and safety data generally have been col-
lected using real-time, direct-reading portable instruments. The
main disadvantage of this procedure is that it can only establish
the presence or absence of volatile organic compounds and only
at levels of mg/1 or greater. Data collected for site characteriza-
tion purposes are used to determine the nature and extent of con-
tamination at a site. This is the process that usually requires the
most data. Site characterization data are generated through
sampling and analyzing waste sources and environmental media.
The site characterization should identify the specific con-
taminants and their concentrations, quantities and physical
states. Often only a few contaminants will play a large role in
determining the overall remedy for site contamination. These
substances are called indicator parameters. Indicator parameters
usually "represent" groups of substances; however, in this con-
text, indicators mean a small set of substances which by reason of
their large volume, high toxicity, difficulty of treatment or
mobility determine the overall remedy and/or degree of con-
tamination. It is important to identify and relate other substances
to the indicator parameters when possible.
Once contaminants of concern have been identified, multiple
levels of analytical support may be utilized simultaneously in
response to RI/FS activity. The extent to which screening mech-
anisms can be used depends on their ability to identify contamin-
ants/concentrations of concern. A most powerful form of ana-
lytical support can be developed by integrating aspects of in-
dividual analytical support levels into one collective analytical sys-
tem. The type and design of this analytical system will be deter-
386 SITE REMEDIATION TECHNIQUES
-------
rained by the intended use of the data (i.e., data quality objec-
tives). This analytical system (e.g., screening analyses coupled
with U.S. EPA-approved analysis methods to produce "enforce-
ment quality" data), coupled with a sound sampling plan design,
permits a larger number of samples to be collected and analyzed.
The use of less sophisticated screening techniques initially allows
large numbers of samples to be screened for indicator parameters
and gross contamination quickly and at low cost.
By strategically selecting which samples are to be analyzed at
each analytical support level, a much higher degree of confidence
can be obtained for the overall data set without sacrificing, due to
project resource constraints, either the quantity of samples to be
analyzed or the quality of data produced.
DESCRIPTION OF SCREENING PROGRAM
A Close Support Laboratory (CSL), supplied by the REM II
team, provided field laboratory services to reduce the Contract
Laboratory Program (CLP) load for the Superfund site and to
facilitate decisions regarding the sequence and execution of field
activities. The CSL was audited by the National Enforcement In-
vestigation Center (NEIC), which is the enforcement litigation
arm of the U.S. EPA. The CSL quality assurance (QA) program
adequatedly addressed and implemented the evidenciary pro-
cedures that are required under the CERCLA program (e.g.,
chain-of-custody and document control). In addition, the CSL
QA program and the laboratory itself were approved by the U.S.
EPA for use on CERCLA projects. Fig. 1 represents a summary
of the analytical QA program and the analytical decisions relating
to QC sample analysis in the form of a decision-making flow
chart.
IEF. BTD. WITHIN OC LIMITS!
| MtTHOO BlAMIKBETECTICmLIMIT )
mst |
,Y«t 1 LAB CHECK STD. )
•*"-] WITHIN oc uurrst J
H«
EXCESSIVE DEVIATION
BCTWEEN SIMULTANEOUS
BAMPLEB
EXCESSIVE
DEVIATION
BETWEEN
REPLICATE
ANALYSES
SYSTEM
SAMPLE 1
OR BAD 1
R
49
1LAS CHECK BTD.
WITHM OC LIMITS*
'l
AT1C ERROR
MTCRPERENCEB
ACKQROUHD
BULT
—I""
MULTIPLICATIVE SAMPLE
MTEMPERENCEB THAT
RBQUINE A LONO TUB
PERIOD OR BPICIAL
CONDITIONS TO HAVE A
NOTICEABLE IFFCCT
UPON RECOVERY OF
THE SPIKE
Figure 1
Procedure for Evaluating QC Data from CSL
Screening Analysis Program
The CSL was established near the project site and supplied
preliminary screening data for soil and water samples. This pro-
cedure allowed quantification of a limited number of target com-
pounds and determination of the presence of certain other
materials. The CSL analyzed soil and water samples for indicator
parameters that, although not all highly toxic themselves, are
characteristic of specific waste types or toxins present at the
Superfund site. These indicator parameters included trichloro-
ethylene, total organic carbon, total organohalides, lead, arsenic
and low pH values. The indicator parameters varied from one
sampling site to another, and the CSL analytical procedures were
modified as necessary to allow the staff to focus on specific in-
dicators for each source area within the Superfund site.
Based on the results of initial analyses during the RI, the in-
dicator parameters were revised as appropriate to address the re-
quirements for the duration of the project. Selected split and
duplicate samples were sent to the CLP for complete hazardous
substance list (HSL) analysis in order to provide confirmation of
the CSL results.
The results of the CSL analyses were used primarily to:
• Guide the selection of the aquifer interval to be screened at
monitor well sites. The CSL data were used at each well site to
identify the extent of contamination and the change in con-
taminant concentrations with depth. The screened interval was
chosen to monitor the stratum of highest contaminant concen-
tration that was consistent with the geology of the formation
(e.g., presence of clay seams or buried channels).
• Assist in selecting locations for deep soil borings and Phase II
wells in a timely manner. The CSL data provided a rapid indi-
cation of whether or not contaminants were present at a spe-
cific location. Placement of wells to define the maximum ex-
tent of contaminant migration was improved by the availability
of such data.
• Assist the project health and safety officer to define the re-
quired level of personal protection during drilling activities at
each site and to select decontamination sites and procedures
for field activities.
ANALYTICAL APPROACH
CSL Organics Screening Protocol
Organic constituents were analyzed using an HNu 301 gas
chromatograph with one or more of the following detector types:
FID or PID. Halogenated organic compounds were selectively
analyzed using a Hall-type microcoulometric detector and the
HNu 301 GC. Fig. 2 represents the CSL analysis sequence for
sample characterization. The CSL analytical method menu is
presented as Table 1. The associated QC criteria are summarized
as Table 2.
N«g
-------
Table 1
Close Support Laboratory Analytical Procedures
ruuxirn KHUX anoo
Volitll. ChlorlMttd Ot|utu
VoUlllo Boachlorlutod Otfulei
Aroutlt Volitllo Orfuilci
OriBAOchlortn* footieldoi
Polynuclou AroMtlc lydroearbooj
Chlorlutod Ijrdrftctrbou
towl nwull
VoUtllo Orfulu
tBlrtctoblo OrfMiu
Vnor
L«id
JLrsoalc
Sulfilo
litor
toll
line
toll
••tor
toll
Vottr
toll
four
loll
t«lor
loll
v.t.r
loll
••Mr
loll
t»ur
toll
«0>0
Soil
V«l«r
Soil
1010
1010
•015
MU
MI
tot
tlO
tlO
ill
til
SIM
5101
term
tCCOOB
Rrooo
term
IV-IU
to»o
mi
JUI
M7C
J07C
!n-tt»
*i*-*to
n-*tt
JtO en f.n 1M
'to cn f«n ut
«o cn rut IM
to cn rui IM
to cn r.rt ut
to cn »«t IM
to cn r>ri IM
to cn rut IM
htultrd Mtkadi
'tuntut lot»Wi
CtL (Il-Houo)
CM. »VA
n-iz TVIU
•3-137 */*
}V1C B-lli
n-m
n-us
n-u>
n-uy
30-2>-) *.*'-a»
•0-S7-I DUldrlA
Xk-tVJ ItamUi)
(inn
ii/m
(WO)
(UW
11^01
ivm
(l/»)
(IAD)
(l/ffl)
(l/W)
• Reprawnu in idvitory limit only.
method performance criteria (especially achievable detection
limits) using packed analytical columns. Further sample charac-
terization was performed as dictated by sample-specific project
requirements. Additional organic parameters included:
halogenated volatiles, non-halogenated volatiles, halogenated
semi-volatiles (extractables), non-halogenated semi-volatiles and
chlorinated pesticides. Methods used were standard U.S. EPA
reference methods or in-house modified methods that had been
shown to produce comparable data that had the required defined
performance specifications. Initial screening methods were
developed using reference standards and U.S. EPA QA check
samples spiked into reagent water.
Screening Procedure* for Organic*
Limitations
The procedures for sample extraction and preparation were
developed to provide rapid "screening" of field samples in order
to determine the presence or absence of organic contaminant!.
The procedures were designed to meet project goals with respect
to analysis "turnaround time" and analytical results (i.e., speci-
ficity and sensitivity to the indicator parameters). Confirmation
of compound identity and exact quantitation of sample com-
ponents were not required (such analyses could be performed on a
"sample by sample" basis, if desired). Analytical results thus
represented estimated quantities of "tentatively identified com-
pounds" or of classes of constituents (e.g., non-halogenated
organics) present in the sample. Spikes, recoveries and method
sensitivity may vary due to composition of the sample matrix and
to the presence of interferents that may affect the performance of
the gas chromatographic column.
Interferences
Analytical interferences are minimized due to the selectivity of
the electrolytic conductivity detector. Method interferences may
be caused by contaminants in solvents, reagents, glassware and
the chromatographic system. The analysis of laboratory method
blanks with each batch of samples provided a mechanism for the
routine monitoring of all interferences that would affect
analytical performance.
Contaminants were identified by comparing the retention times
of sample peaks to the retention time of standards. This technique
is not definitive, and identifications were considered tentative.
Two to three column identifications could have been made for
more definite identification, but this procedure requires con-
siderably more time. Analytical conditions did not always max-
imize resolution, which is the ability to separate compounds.
Method development/optimization was conducted as priorities
dictated. Since compound identifications were tentative, exact
resolution was not always critical. The desired analytical resolu-
tion was determined by the objectives of the sampling.
Relative measurements of contaminant peaks were accom-
plished by comparing the peak heights of contaminants to the
peak heights of the standards and utilizing the following formula:
„ . L - ,_ SAM SAM
Peak height —— x attenuation x
STD
SAM
STD
x concentration STD
(D
STD
Injection
where:
SAM = sample
STD = standard
Since concentration measurements by these methods were based
on peak height rather than peak area (integration), the values
generated are approximate. Numbers were reported in ranges
where appropriate to avoid misinterpretation of the data. The
limitations, tentative identifications and approximate concentra-
tions were noted on all analytical reports and in all presentations
of the data.
EXPERIMENTAL SUMMARIES:
SOIL AND WATER QUALITY
Split samples from all soil and groundwater sampling efforts
were submitted to the CSL. The CSL performed screening
analyses on the various samples to provide rapid (usually less than
2-hour turnaround time) assessment of the presence or absence of
organic contamination.
The original work plan called for the CSL to perform screening
analysis for volatile and extractable organic compounds and
388 SITE REMEDIATION TECHNIQUES
-------
specific analyses for three inorganics (arsenic, sulfate and lead)
and one organic (phenol). The additional time required for the
specific inorganic and organic analyses, however, created an
unacceptable delay (in terms of time and cost) in field activities,
specifically in selecting the depth interval to be screened and com-
pleting the well. Consequently, these specific analyses were not
performed. The CSL did perform analyses for volatile and extrac-
table organics as described in the sections below.
EXTRACTABLE ORGANICS ANALYSIS
SoU
Approximately 10 g (recorded to the nearest 0.1 g) of well-
mixed, undried soil were weighed into a 100 ml serum bottle. Ten
ml of 50% acetone/50% hexane were then added (complete im-
mersion of the soil was required). The bottle was capped and then
sonicated for 10 min. Subsequently, the extract was allowed to
settle and then was decanted into a 16 ml glass vial (Teflon-lined
cap) containing approximately 1 g of sodium sulfate. The
resulting extracts were stored at less than 4 °C until gas chroma-
tographic analysis.
Water
Approximately 10 g of water (recorded to the nearest 0.1 g)
were weighed into a 16 ml vial having a Teflon-lined cap. Two ml
of hexane were added, and the vial was capped and shaken for 1
min. The phases were allowed to separate for 10 min. The hexane
phase then was transferred with a clean Pasteur pipet to a 5 ml
septum-sealed vial containing approximately 0.5 g of sodium
sulfate. The extracts were stored at less than 4°C until required
for gas chromatographic analysis.
Table 3
Extractables Duplicate Sample Pair "Peak Response Precision'"
Dupllcut
Mr I.D. Matrix
1. SoU
1. DifUeate
2. SoU
2. Duplicate
3. SoU
3. Delicate
'• Soil
'• Utter
i. Duplicate
'• Water
'• Duplicate
'• Utter
8. D^Ucate
'• Utter
'• Duplicate
* Hater
10. Duplicate
Peak 2 RFDof
Response Response
NoResponse —
Detected
NoResponse
Detected
200 86
500
SCO 22
400
NoResponse —
Detected
NoResponse
Detected
12,000 22
15,000
w Response —
Detected
NoResponse
Detected
No Response ~—
Detected
NoResponse
Detected
ND F£spcnM -**•
Detected
NoResponse
Detected
rb Response —
Detected
NoResponse
Detected
Reported Estimated Concentrations
Range for Selected Peak
No peaks detected,
Lov ppn range
tow ppn range
No peaks detected,
Lav ppn range
No peaks detected,
No peaks detected,
No peaks detected,
No peaks detected.
MX - 0.5 ppn
HX - 0.5 ppn
MX- 10 ppb
HX- 10 ppb
MX- 10 ppb
MX- 10 ppb
Quality Control
Spiked samples and duplicates were analyzed at a minimum fre-
quency of one per 10 samples extracted and a minimum of one per
batch of samples. The matrix spikes were prepared by spiking ap-
proximately 10 g of sample (recorded to the nearest 0.1 g) with
amounts of standards to give levels of 5 mg/1 p,p'-DDT and 2
mg/1 dieldrin. A method blank was prepared for each sample ex-
traction batch.
Initial and final calibrations were performed daily using a stan-
dard mixture of 5 ng//tl p,p'-DDT and 2 ng/jd dieldrin. Instru-
ment conditions were adjusted to achieve a minimum response of
one-half full-scale detection. Chromatographic temperatures, in-
strument attenuation, retention times and responses (peak height)
of analytical standards were recorded daily. A QC check sample
was analyzed routinely to calibrate retention time range for the
organochlorine pesticide class. A weekly three-point calibration
was performed to ensure linearity across the attenuation range
(i.e., at all attenuation settings) of the chromatographic detector.
The duplicate sample analysis results are summarized as Table 3.
The spiked sample analysis results are summarized as Table 4.
Table 4
Extractables Spiked Sample Recovery: Acceptability Criteria'
Staple
X.D.
1
2
3
4
5
6
7
a
9
10
Spike taunt
Hatrix
Viler
Utter
Utter
Uater
Utter
Soil
Soil
SoU
Soil
SoU
an
»w*
»ppb
MB*
5
X
5ppn
2pp.
3pp.
SfP"
SK»
Dieldrin
20 ppb
20 pf*
20 ppb
2
20
2ppm
Ippi
2pp.
2K-
2PP"
Percent Recovery
an
93
45
63
57
100
93
75
58
103
90
DieUrin
94
71
78
57
92
70
61
59
129
93
Reported Concentntlon
Ranges of Sample Ccaponents
Ho peek] detected, MX - 10 ppb
No peaks detected, MX - 10 ppb
(to peaks detected, MX . 10 ppb
No peaks detected, MX. . 10 ppb
No peaks detected, MX - 10 ppb
No peaks detected, MX - 0.5
Pf»
7 peaks detected in the high
ppb to low ppn range
8 peaks detected in the high
ppb- to low ppn range
No peaks detected, MX - 0.5
PP"
No peaks detected, MX - 0.5
PP»
1 Target value for RDP = 50
2 p»k response listed for sample peak having retention time closest to dieldrin peak. (Peak re-
>P
-------
nique. Sample I.D., attenuation setting and injection volume
were recorded. The extracts were screened at the attenuation set-
tings at which the standard calibration was performed. Attenua-
tion was adjusted to keep sample response peaks on-scale. Levels
of peaks detected were estimated by the comparison of the peak
heights of the sample to the peak heights of standard p.p'-DDT
and dieldrin. Samples for which the detector response was out of
the attenuation range of the chromatographic detector were
diluted with hexane and reinjected.
VOLATILE ORGANICS ANALYSIS
Approximately 10 g of well mixed sample (soil or water),
recorded to the nearest 0.1 g, were weighed into a tared 100 ml
serum bottle. The bottle was crimp-sealed with an aluminum seal
containing a Teflon-lined rubber septum. The bottle was allowed
to equilibrate 1 hour in a 90 °C water bath before chromatograph
analysis.
Quality Control
Spiked samples and duplicate samples were analyzed at a fre-
quency of one per 10 samples analyzed and a minimum of one per
batch of samples. The samples were spiked with a U.S. EPA QC
check sample using an amount which gives levels of 60 pg/1 tri-
chloroethylene and 30 jig/1 tetrachloroethylene. A reagent and
glassware blank was prepared and analyzed with each sample
batch.
Initial and final GC calibrations were performed daily using an
aliquot of deionized water spiked at levels of 50 /tg/1 trichloro-
ethylene and 250 /ig/1 toluene. Chromatographic temperatures,
instrument attenuations, analytical standards retention times and
responses were recorded daily. A multilevel calibration (range =
50 pg/1 to 5 mg/l TCE, 100 /ig/1 to 5 mg/1 toluene) was performed
on a weekly basis using toluene for FID calibration and a toluene
Table 5
Volatile Duplicate Sample Pair "Peak Response Precision'"
Itlr I.D.
Mitrlx
W> of Aaporled btliBtad Cbnoantratlcn
ftanaa forSalactad Mi
1.
1. OuplldU
2.
2. tXajllau
3.
3. OxJJcau
4.
4. baillau
1.
5. OlUieaU
i.
t. ttjOJcat.
7
7 Dtadlcau
a
6 Oa>Uau
9
9 Dupllcau
10.
10. ttaillcat.
Soil
Soil
Soil
Sail
Soil
Soil
Soil
Soil
Ihlar
thur
Uktar
feur
SoU
SoU
Uaur
Ifcttr
feur
Uaur
Ihtar
Uat«r
fetaipn. -
Oaucud
K> Haayiiai
teucud
40 M.6
ao
320 U.a
360
800 U.2
960
60 0
60
feUaapra* -
tetactad
feRaapna
tetactad
1,040 7.4
1,120
3,200 0
3,200
360 10.)
40)
640 22.2
600
00 ppb
lav ppb rmifi
Uw ppb rar*»
IMlMppb can|«
U* ppb ranfl
00 ppb
tadlM ppb [«*•
Hl^i ppb rana*
Lav ppb nngi
Hadluappb rar««
1 The target value Tor duplicate precision KPD » 50%.
2 Peak response lilted for iimple peak having retention dmc close*I to TCI- peak. (Peak re-
sponse - peak height s attentuation factor.)
3 Reported ranges for volatile analysis (bated on TCE response)
and trichloroethylene mixture for PID calibration. The calibra-
tion standards were prepared in DI organic-free water.
These extended range calibration curves were used to estimate
amounts of sample component responses which fell out of the
daily standard attenuation setting (i.e., amounts greater than that
in the normal working range). The daily matrix spike was com-
pared to the multilevel calibrations to assure acceptable correla-
tion between sample matrix spikes and deionized water calibra-
tion spikes. The volatile analysis PID calibration was performed
at five calibration points ranging from 50 p.g/1 TCE to 5 mg/1
TCE. The mean RF and percent RSD were calculated for the
multilevel calibrations. The target value for percent RSD was for
<25V«. The daily matrix spike was at a level of 60 jtg/1 TCE.
The duplicate sample analysis results are summarized in Table 5,
and the spiked sample analysis results are summarized in Table 6.
Table 6
Volatile* Spiked Sample Recovery:
Response Ficlor Acceptability Criteria'
I.B.
SpUu
Wat Saapl*
*trl* Spite tr
Ttetar. vj. Calibration, ftap
at Vf Sunoard W »••"
1
1
3
«
3
(
7
1
*
10
fetar
Ifctar
Ma tar
toll
Iktar
•alar
Soil
Soil
Soil
fell
«ppb
60 ppb
60 ppb
WPP*
We*
«PP»
to ppb
»ppb
«ppb
«H*
J.3
4.0
J.O
J.3
4.0
4.0
4.0
4.0
4.0
4.0
a
9
3.1
1.*
0
».l
».l
20.8
204
11.1
W> paakj oatacud, NX - 90 H*
1 pi* in t*a lw npb ran*
1 paak la ttandliai >hlttppb
rmfa
M> paakj datactad, MX. - 30 Rk
1 paafc in &* Ion ppb twin
1 paak la tht loippbranai
2 paata la tha lovppb ranji
3 paakj la *• 1» ppb ntaja
1 paak la lh> lav ppb atft
1 pHk la the w*ibm ppb m|<
I The uifd critcru for *tD »u 15*^
2 Roponjc Tictor • TC£ rtsponse-'amount (ppb)
] %D - {RF daily calibration ilandard) — (RF sample spike) RF daily calibration iundard
(daily calibration iiandaid <• 90 ppb TCE in DIH2O)
Gas Chromatography
The following instrumental and chromatographic conditions
were used:
• Analytical Column: 180 cm x 0.3 cm Stainless Steel
• Column Packing: 5«7o AT-1200/1.15% Bentone-34 on 100/120
Chromosorb WAW
• Column Temperature:
63 °C initial, 2 min hold time
6°C/min to93°C final
• Detector/Injector Temperature: 150°C
• Carrier Gas: Helium 40 ml/min
Chromatography
A 4 ml portion of the sample headspace was injected into the
gas chromatograph. Sample I.D., injection volume and instru-
ment attenuation were recorded. Initial attenuation was set at the
same level (setting) that had been used for the calibration stan-
dard analysis and was subsequently adjusted to keep sample
response peaks on-scale. Concentration levels of peaks detected
were estimated by comparing sample peak heights to the standard
calibration curve peak heights.
390 SITB REMEDIATION TECHNIQUES
-------
RESULTS AND DISCUSSION
CSF Quality Assurance (QA) Program
The CSL QA program for screening analysis included the fol-
lowing key QC procedures: (1) Establishment of linear working
range using a five-point calibration curve, (2) weekly three-point
calibration range linearity verification using U.S. EPA reference
standards, (3) daily continuing calibration check, (4) duplicate
sample analysis at a minimum frequency of 10% per matrix, (5)
spiked sample analysis at a minimum frequency of 10% per
matrix, (6) reagent blank analysis at a minimum frequency of
10% per matrix, and (7) the limit of quantitation (LOQ) was de-
termined daily by calculating the peak response for a matrix spike
of reagent water or background soil.
Due to the nature of screening analysis protocols and the
method for reporting results, the QC criteria for the above pro-
cedures were considered to establish advisory limits only. Data
were not "rejected" on the basis of exceeding the QC limits,
although samples may have been reanalyzed if the criteria were
grossly exceeded.
Analytical Results
Selected representative analytical results are presented in Tables
7 and 8 as comparative examples of the sample analysis data as
reported by the CSL and by the CLP laboratory. In order to
assess the equivalency of these two data sets, the following factors
must be considered: (1) relative detection limits, (2) analytical
selectivity, (3) method of reporting and (4) intended use of each
data set.
In order to use CLP data for project purposes, the data first
must be "validated" according to specified U.S. EPA protocols
by trained data validation specialists. The data validation task for
the Phase I samples of this project was estimated to require 1300
Table 7
Comparison of CSF VolatUe Results Versus
Contract Laboratory (CLP) Results'
Siaple Saaple
I.D. Hatrlx CSF Reported Data
CLP Reported Data
1 peak in the high ppb to
lov ppa range
25 peaks In the Bediu« pp*
to high pp* range
Soil
Soil
No peaks detected,
NOL . 30 ppb
1 peak in the high ppb to
lov ppB range
Hater' 5 peak! In the.high ppb to
lov ppa range
Ethyl Benzene - 11,000 ug/Kg
Total Xylenes . 41,000 ug/Kg
Chloroform . 820 ug/Kg
Nethylene Chloride > 5,800 ug/Kg
Ten Tentatively Identified
compounds ranging fro* 790 to
2,400 ug/kgz
Chlorofora • 8 ug/Kg
1 tentatively identified coapound
at 5 ug/Kg
1,1,1-Trlchloroethane . 740 ug/Kg
Ethyl Benzene - 890 ug/Kg
Total Xylenes . 4,700 Ug/Kf
1 tentatively identified compound
at 600 ug/Kg
I Validated results were available for only a few of the samples analyzed by the Contract Labora-
tory, thus a full database comparison of CSF vs. CLP results cannot be performed at this
time.
2 The remaining HSL volatiles were reported as less than the sample detection limits. The
sample detection limits were reported between 1,600 and 3,300 jig/kg due to the required dilu-
tion to bring the reported compounds within the CLP calibration ranges.
3 Chloroform is not detected by the PID detector and has a low response to the FID detector
due to the high degree of chlorination.
4 Based on the retention time and a negative PID response, this result is indicative of methanol
present in the sample. Methanol was used by field sampling personnel during decontamina-
tion procedures. Based on this result, the field sampling personnel were advised to allow
longer periods of drying time for the surface soil sampling equipment before proceeding
with the next sampling site.
5 The CSF chromatographic fingerprint was observed to be indicative of ethyl benzene and
xylene isomers. The deionized water obtained for drilling rig decontamination procedures was
found to be contaminated, prior to use, by the CSF results. This data prevented contamina-
tion of the drill site locations and the samples collected by the use of this deionized water for
•Wiling rig decontamination procedures.
6 Decontamination procedure rinsate.
hours and has not been completed in time to reference the entire
Phase I data base in this publication, whereas the CSL staff was
able to provide useful data to the project management and field
crews in a time frame of several hours. Two examples of useful in-
formation obtained during CSL screening follow.
On the basis of the analysis of decontamination rinsate
samples, the CSL discovered after the first day of monitor well
drilling that the decontamination rinse water source had been
contaminated with several organic compounds by a storage tank
that had not been adequately cleaned to remove organics. The
CLP corroborated this finding with enforcement-quality data.
Table 8
Comparison of CSF vs. CLP Extractable Data Results'
Sample
I.D. Matrix
1 Soil
2 Soil
CSF Reported Data2
No peaks detected,
MQL - 0.5 ppm
9 peaks In the high ppb to
lov ppm range
The peaks wre vithin the
retention time range for
Organochlorine Pesticides
dP Organochlorine
Pesticides Reported Data
No pesticides reported
Sample Detection Units 10 to 200 ug/Kg
Heptachlor . 150 ug/Kg
4,4'-OE . 830 ug/Kg
Bndrin . 210 ug/Kg
4,4' -CO) . 540 ug/Kg
4,4' -COT - 5,700 ug/Kg
Bidrin Ketcne - 490 ug/Kg
Oilordane . 1,196 ug/Kg
Soil No peaks detected,
MQL - 0.5 ppm
Soil 8 peaks in the high ppb to
low pp* range
The peaks vere vithin the
retention tine range for
orgatochlorine pesticides
No pesticides reported
Sample Detection Units 82 to 1,600 ug/Kg
Heptachlor - 1,100 ug/Kg
Dieldrin . 960 ug/Kg
4,4'-tie - 3,100 ug/Kg
4,4'-T£0 - 1,900 ug/Kg
4,4'-Oir - 17,000 ug/Kg
Bidrin Ketcne . 1,400 ug/Kg
Chlordane . 4,670 ug/Kg
1 Validated results were available for only a few of the samples analyzed by the contract labora-
tory, thus a complete database comparison of CLP vs CSF results cannot be performed at
this time.
2 CSF reported concentration ranges for extractables
High ppb = 500 ppb to 1 ppm
Low ppm = 1 to 10 ppm
3 Chlordane exhibits a multipeak response
Similarly, the CSL reported that the decontamination pro-
cedure for the surface soil collection equipment was inadequate to
remove all residual methanol from a decontamination solvent
rinse step. The CSL reported a positive methanol value for the
decontamination rinsate sample. The CLP laboratory did not
report finding methanol per se or as a tentatively identified com-
pound. The analytical protocols for CLP routine analytical ser-
vices, however, do not allow for the detection of methanol. Con-
sequently, this problem would not have been discovered if the
CSL had not been utilized or if the CSL staff had not been aware
of the specific project procedures.
CONCLUSIONS
The Close Support Laboratory and analytical screening pro-
tocols concepts as implemented for this project allowed for the
production of reliable analytical data on a short turnaround basis.
The analytical services provided were relatively low-cost com-
pared to commercial or CLP laboratories and addressed project-
specific requirements.
Due to the nature of the screening program (i.e., relative low-
cost compared to standard GC protocols) and quick turnaround
(approximately 2 hours/sample), the following benefits to the
project were realized: Selected priority and enforcement-sensitive
samples could be sent to the CLP laboratory for confirmation of
screening results; the accuracy of the site characterization and
contaminant plume(s) mapping was significantly improved as a
SITE REMEDIATION TECHNIQUES 391
-------
result of the increased number of samples that could be analyzed conditions and to select subsequent well locations, soil borings
with a fixed project budget; the responsiveness of the analytical and screened intervals in wells on the basis of reliable data rather
staff to changing project requirements and schedules was in- than previously assumed conditions or estimates.
creased as a result of the large degree of communication with the As can be seen from a review of the data in Tables 3 to 8, the
field personnel. CSF screening methods provided accurate reproducible analyses
This procedure enabled the field staff to better understand site within the limits of the screening program.
392 SITE REMEDIATION TECHNIQUES
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The U.S. EPA's Expedited Response Action Program
Robert D. Quinn
William M. Kaschak, P.E.
U.S. Environmental Protection Agency
Washington, D.C.
J. Steven Paquette
Wendy L. Sydow
CDM Federal Programs Corporation
Annandale, Virginia
ABSTRACT
Revisions of the National Contingency Plan redefine the re-
sponse categories of "removal actions" and "remedial actions"
so that removals now include all activities formerly considered
immediate removals, planned removals and Initial Remedial
Measures (IRMs). These changes in response categories will ex-
pedite many cleanup activities.
A program is being implemented by the Hazardous Site Con-
trol Division of the U.S. EPA to facilitate response actions at
NPL sites. These actions are referred to as Expedited Response
Actions (ERAs). Removal actions taken under this program will
be performed by remedial contractors to ensure continuity with
remedial investigation/feasibility study (RI/FS) activities and
schedules as well as consistency with final remedial alternatives.
The approach will entail the use of an Engineering Evaluation/
Cost Analysis procedure, plans and specifications development,
competitive bidding and construction management to plan, de-
sign and implement the project.
The main benefit of the ERA process is that it results in the
cleanup of site contamination without the implementation of a
full RI/FS. As a result, obvious technical site cleanup alterna-
tives can be selected, designed and implemented on a fast-track
basis.
The authors describe the concept of the ERA Program and
how it will improve the U.S. EPA's ability to rapidly clean up
NPL sites. The procedures that are in use to implement the pro-
gram are explained, and an example of an ERA that has been
conducted is discussed.
INTRODUCTION
An expedited response action (ERA) is a removal action im-
plemented at an NPL site by a remedial response contractor. The
action must be conducted within the time and cost constraints of
removal actions. The statutory limits of $1 million and 6 months
currently apply; these are expected to be revised upward when
CERCLA is reauthorized. These actions may include initial meas-
ures at a site slated for a comprehensive remedial action later
(these used to be called IRMs, initial remedial measures), a rapid
cleanup required based on data collected during an ongoing re-
medial response, or a permanent remedy for a site with limited
cleanup requirements.
As defined by Section 101(23) of CERCLA and cited in Section
300.6 of the NCP, "remove or removal means the cleanup of re-
leased hazardous substances from the environment; such actions
as may be necessary to monitor, assess and evaluate the release
°r threat of release of hazardous substances, the disposal of ma-
terial or the taking of such other actions as may be necessary to
Prevent, minimize, or mitigate damage to the public health or
welfare or the environment...." Based on this definition, a re-
moval action may include capping, on-site treatment or other
measures in addition to or in place of actual removal of hazardous
materials. The term "remedial action," then, refers to work con-
ducted under the U.S. EPA's CERCLA remedial response pro-
gram, which includes long-term cleanups with the objective of a
permanent remedy for the site. An ERA is an action under the
CERCLA removal authority, conducted by a remedial contrac-
tor at an NPL site. Removal actions that must be accomplished
quietly and actions at sites that are not on the NPL will be con-
ducted by removal contractors.
The purpose of the ERA is to accomplish rapid cleanups by
streamlining the remedial investigation/feasibility study process
for operable units or sites where the most effective mitigation
method is readily evident. The level of detail required in the
analysis of alternatives for these actions depends on the urgency
of the required response.
General guidelines for determining the suitability of a site for
an ERA include the following:
• The circumstances meet removal action criteria
• The ERA remedy is consistent with the final permanent remedy
• The remedy can be accomplished within the statutory cost and
time constraints specified for removal actions
PURPOSE
The primary purpose of conducting an ERA is to expedite
cleanup at NPL sites where solutions are clear and where an emer-
gency situation does not exist but a release or threat of release
exists. ERAs may include removal actions that need not be done
immediately; in this case they will use a response schedule that
will allow for completion of an engineering evaluation/cost analy-
sis and competitive procurement of a construction subcontractor.
Besides expediting the cleanup of hazardous waste situations, the
ERA also:
• Accomplishes partial site cleanup consistent with remedial re-
sponse actions
• Makes future RI activities easier to accomplish by removing or
controlling on-site wastes
• Improves the public perception of the Superfund program by
rapidly accomplishing partial site cleanups or by furnishing
alternative water supplies
The analysis of alternatives in an ERA is documented in an en-
gineering evaluation/cost analysis report. This document serves
as the basis for the action memorandum (EPA's decision docu-
ment for removal actions), much as the RI/FS report serves as
the basis for the Record of Decision for remedial projects.
SITE REMEDIATION TECHNIQUES 393
-------
COORDINATION OF REMOVAL AND
REMEDIAL PROGRAMS
The selection of a remedial or removal contract vehicle for the
conduct of a removal action involves multiple factors. The selec-
tion is based on the time critical nature of the response, the status
of on-going site activities, long-term plans for the site, exper-
ience and capability of the remedial project manager or on-scene
coordinator, technical expertise required and contract capacity
and accessibility. Guidelines for determining the lead program
for removal actions are diagrammed in Fig. 1.
All removal actions, regardless of program lead, must be con-
sistent with CERCLA and the NCP. Response activities under
the removal authority are characterized by an urgency of re-
sponse that affects the extent to which they must address cer-
tain areas specified in the NCP. As specified in Section 300.65
of the NCP, "removal actions shall, to the greatest extent prac-
ticable, considering the exigencies of the circumstances, attain or
exceed applicable or relevant and appropriate federal public
health and environmental requirements."
THE ERA PROCESS
ERA and the RI/FS Process
The ERA normally will proceed concurrently with an RI/FS
assignment. However, these two activities share only front end
data collection tasks. The goal of the ERA process is to break out
feasible ERA units from an RI/FS assignment and fast-track the
evaluation of alternatives for these discrete contamination situa-
tions. In this way, the ERA evaluation can proceed rapidly to
the point where a decision about the potential for design and im-
plementation of an ERA can be made. If ERA criteria are satis-
fied, then the ERA process results in a rapid cleanup of part or
all of a hazardous waste situation. If the ERA criteria cannot be
satisfied, then either a full or limited RI/FS can proceed with
little or no interruption. A diagram showing the relationship of
the ERA process to a typical RI/FS assignment is presented in
Fig. 2
ERA Components
An ERA is conducted in four phases in which feasible removal
actions are screened, evaluated, selected and implemented. ERA
activities include the following:
• Phase I—Preliminary Screening of ERA Alternatives
• Phase II—Engineering Evaluation and Cost Analysis (EE/CA)
• Phase III—Design and Contractor Procurement
• Phase IV—ERA Implementation
In Phase I of an ERA study, data gathering activities com-
mence (Fig. 3). At this stage in the ERA evaluation, data needs
particular to the complete ERA evaluation will be identified. Pre-
liminary ERA candidate option screening will address issues such
as:
• Potential for quick cleanup
• Identification of ERA alternatives that would be consistent
with remedial response actions
• Likelihood of remedies being completed on a fast-track time
schedule with a limited amount of engineering or expensive
data gathering
• Compliance with initial ERA inclusion criteria
If a site meets the initial ERA screening criteria, then a Phase
II ERA evaluation will be conducted. In Phase II, data gaps are
filled, and an engineering evaluation and cost analysis (EE/CA)
is completed (Fig. 4). The results of the EE/CA are compiled in
an EE/CA report. After review by the U.S. EPA, the report is
issued for public comment. During the public comment period,
Figure 1
Decision Tree for Removal and ERA Projects
Figure 2
Relationship of ERA Process to RI/FS Assignment Flow
Figure 3
ERA Phase I—Preliminary Screening
394 SITB REMEDIATION TECHNIQUES
-------
DEVELOP
DETAILED
OPTIONS
EVALUATE
- PUBLIC HEALTH/
ENVIRONMENTAL
- TECHNICAL
- COST
- INSTITUTIONAL
I
DRAFT
EE/CA REPORT
1
PUBLIC
COMMENT
FINAL
EE/CA REPORT
ACTION
MEMORANDUM
Figure 4
ERA Phase II—Engineering Evaluation/Cost Analysis
the contractor may proceed with initial preparation for design of
the removal action.
When an ERA alternative is selected for implementation, Phase
HI is conducted (Fig. 5). In this phase, the contractor prepares
Invitation for Bid (IFB) or Request for Proposal (RFP) contract
documents, advertises and conducts the bid or proposal evalua-
tion. Selecting the cleanup firm is EPA's prime contractor's re-
sponsibility.
During Phase IV, the cleanup contractor is notified to initiate
the execution of the remedial work (Fig. 5). Upon completion of
the work, an ERA Completion Report is prepared which sum-
marizes the technical and financial aspects of the ERA and com-
pares these actual results to the initial estimates.
ENGINEERING EVALUATION/COST ANALYSIS
An engineering evaluation/cost analysis (EE/CA) will be con-
ducted for removal actions where time permits. The EE/CA is
conducted in Phase II of the ERA process, beginning with a lim-
ited number of alternatives that have been selected through
screening in Phase I. Phase II entails refinement and specifica-
tion of the alternatives, followed by a detailed analysis based on
DEVELOP IFB OR
RFP DOCUMENTS
FOR CLEANUP
ADVERTISE
PROCUREMENT
EVALUATE
RESPONSES AND
SELECT CLEANUP
CONTRACTOR
CONTRACTOR
AWARD
NOTICE TO
PROCEED
OVERSIGHT AND/OR
CONSTRUCTION
MANAGEMENT
PRE-FINAL AND
FINAL
INSPECTIONS
I
ACCEPTANCE
OF WORK
ERA
COMPLETION
REPORT
Figure 5
ERA Phases III and IV—Design, Procurement and Implementation
SITE REMEDIATION TECHNIQUES 395
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the following criteria:
• Public health, welfare and environmental impacts
• Technical feasibility
• Institutional considerations
• Cost
The evaluation addresses areas that also are considered in the
overall RI/FS for the site. Potential impacts upon public health,
welfare or the environment are evaluated for each alternative
with the purpose of eliminating alternatives that may have signif-
icant adverse impacts or may not adequately protect the environ-
ment. Under technical considerations, each remedial alternative
is evaluated for performance, reliability, implementability and
safety. Institutional concerns include the areas of community
relations, PRP involvement, permit requirements and compliance
with relevant and applicable regulatory requirements. Evaluation
of costs should consider estimation of costs, present worth analy-
sis, sensitivity analysis and summarization of alternatives
analysis. The level of detail of the analysis will be commensurate
with the complexity of the proposed project.
The results of the detailed evaluation of response alternatives
will be compiled in the EE/CA report. The EE/CA report pro-
vides the U.S. EPA decision-makers with the information needed
to select an alternative for implementation. The EE/CA report
will form the basis for the ERA Action Memorandum, the U.S.
EPA's decision document for the expedited response action.
Evaluate Data Requirements
Data collected during the initial site visit, the extent of contam-
ination survey and any additional specific limited site visits pro-
vide the data base for the screening and detailed analysis of
alternatives.
If the initial site visit is conducted with adequate considera-
tion for the alternatives defined in Phase I, the data base should
be adequate to complete the EE/CA. Any followup data collec-
tion activities should focus on the needs for properly assessing
alternatives. Some examples of follow-up activities include:
• Verification sampling and analysis
• Analysis to clearly define extent of contamination
• Determination of actual or potential exposure to hazardous
substances, pollutants or contaminants by nearby populations,
animals or food chain and assessment of health impact of such
exposure
• Characterization of waste material for detailed determination
of process applicability
• Pilot testing of various solidification/fixation agents with waste
material
• Detailed analysis of embankment or dike stability for support
of heavy equipment
Development and Analysis of Alternatives
Each candidate alternative must be developed in sufficient de-
tail for comparative analysis. Utilizing the base map and other
data obtained through the initial site visit and other data collec-
tion activities, site-specific descriptions of each alternative are
developed. The chronology and implementation schedule for each
alternative also is considered under the technical evaluation. The
descriptions of the alternatives should include the following:
Plan of operations
Ancillary support requirements
Contingency requirements
Equipment needs
Operations and maintenance
Sidestream waste generation and management
Off-site disposal requirements
Easements
396 SITE REMEDIATION TECHNIQUES
Engineering and Technical Feasibility
The technical feasibility of each alternative should be sum-
marized in terms of expected performance, reliability, imple-
mentability and safety. Technical evaluation of the alternativei
also must consider the applicability of alternative technologies to
the site, whether or not the alternative results in a permanent
remedy, and if the alternative it consistent with the final remedy
for the site.
The implementation schedule also is taken into consideration
as part of the technical evaluation.
Cost Analysis
The objective of this activity is to develop cost estimates for
each alternative. Cost accuracy should be within a targeted range
of +50% to -307*. Costs should include implementation, de-
sign and construction contingencies, construction management,
operations and maintenance and closure/post closure, as applic-
able.
Summary of the Alternatives Evaluation
The results of the detailed assessment of the alternative ERAi
should be assembled and analyzed on a comparative basis. For
each alternative, the summary should present the following in
tabular form:
Public health and environmental concerns
Estimated construction cost
Technical concerns
Construction concerns
Compatibility with final remedy
This analysis should include the reasons for differences among
alternatives. For example, if costs are significantly different, the
basis for this difference should be presented. It also should be
noted if the alternatives result in permanent remediation or if
they require followup remedial or removal activities.
CASESTUDY
One of the first ERAs conducted was for the Gregory Incline
and Tailings site, part of the Clear Creek/Central City NPL site
in Colorado. The Clear Creek site consists of five sources of acid
mine drainage and unstable tailings that resulted from hard rock
mining and milling. The sites are located in one of the most con-
centrated areas of hard rock mining in Colorado; there are over
800 abandoned mine workings and adits located in this mining
district around the Central City /Black Hawk area.
A potential environmental threat was identified at the Gregory
Incline and Tailings site during field investigations as part of an
on-going RI/FS. A timber crib retaining wall, built between
1880 and 1889, supports mine tailings contaminated with heavy
metal. This wall has failed in part and has deteriorated to the
point that mass failure of the wall is imminent. The general site
layout of the Gregory Incline and Tailings site is shown on Fig. 6.
Alternative Analysis
The preliminary screening analysis evaluated the feasibility of
five various remedies to correct the unstable tailings at the
Gregory Incline and Tailings site. These alternatives included the
following:
No action
Stabilize the tailings slope
Replace the retaining wall
Remove the tailings
Isolate the creek from the tailings
Preliminary screening of these alternatives revealed that the re-
moval of the tailings alternative exceeded ERA cost constraints,
and an extension could not be justified. In addition, the no action
-------
alternative was unresponsive to CERCLA goals. The remaining
three alternatives were evaluated in more detail. As part of the
detailed analysis, three variations of the wall replacement alterna-
tive were identified: reinforced earth, rigid retaining wall and
flexible retaining walls.
Figure 6
Gregory Incline and Tailings Site Layout
Compatibility with Final Remedy
The alternatives proposed to stabilize the tailings were deter-
mined to be compatible with the permanent remedy for the Clear
Creek site, which includes isolation of the tailings and control of
seepage water quality. Based on preliminary analysis conducted in
the on-going RI/FS for the Clear Creek site, the most cost-effec-
tive solution to controlling the spread of toxic tailings will be to
leave the tailings at their present location, isolate them from direct
human or animal contact and prevent their migration off-site
through water or wind erosion.
The seepage of acidic waters rich in heavy metals was iden-
tified as a potential problem during Phase I of the ERA. Mitiga-
tion of this seepage through installation of a drainage system is
beyond the scope of the ERA but could be installed as part of
the long-term remedy for the site subsequent to construction of a
retaining wall without any additional cost.
Cost and Schedule
The cost to implement any of the alternatives analyzed ranges
between $467,600 and $553,800. With an upper limit of $1
million, up to $532,400 could be available for additional ERA
action within the 6-month timeframe. Time required for construc-
tion of the alternatives ranges from 4 to 5 months.
Institutional Considerations
Institutional issues addressed in the EE/CA for the Gregory
Incline and Tailings site included permit requirements, respon-
sible party considerations and community relations.
Investigators identified two permits typically required for the
type of construction proposed for the ERA alternatives under
consideration for this site. These are a U.S. Army Corps of En-
gineers, Section 404 Individual Permit for dredge and fill in
waterways and a Colorado Department of Health, Section 401
Water Quality Certification and construction dewatering dis-
charge permit. The site may be exempt from some on-site permit
requirements because of its status as a CERCLA site.
To address community relations, a fact sheet on the ERA for
Gregory Incline and Tailings was prepared for distribution after
issuance of the EE/CA report, with a 3-week comment period.
CDM also coordinated with the owner of the site in discussion of
the approach to be taken in the analysis of the ERA alternatives.
The results of the EE/CA are documented in the EE/CA re-
port completed in June 1986. The report includes a summary
matrix addressing the following for each alternative:
Estimated construction cost
Estimated construction time
Technical concerns
Construction concerns
Compatibility with final remedy
CONCLUSION
Expedited response actions are one of several methods the U.S.
EPA is looking at to improve the efficiency and effectiveness of
Superfund response actions. By using the remedial contractor to
complete non-time critical removal actions at NPL sites, the re-
moval can be accomplished with minimal interruption of the re-
medial cleanup effort. This also will minimize confusion or com-
plications resulting from having multiple contractors on-site. It is
likely, however, that there will be occasions when multiple con-
tractors must be used to address different issues at the site. In
these situations, the RPM and OSC must coordinate closely to
keep site operations as efficient as possible.
The results of several ERAs currently underway will be ana-
lyzed to assess the effectiveness of ERAs in achieving site clean-
ups. Based on experience gained at these sites, guidance under
development by the U.S. EPA will be modified to improve the
process for the technical approach and procedures for coordina-
tion between the removal and remedial programs.
SITE REMEDIATION TECHNIQUES 397
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Data Quality Objectives Development for
Remedial Investigation/Feasibility Studies
Linda Y. Boornazian
U.S. Environmental Protection Agency
Office of Waste Programs Enforcement
Washington, D.C.
Randall Kaltreider
U.S. Environmental Protection Agency
Office of Emergency and Remedial Response
Washington, D.C.
Tom A. Pedersen
Camp Dresser & McKee Inc.
Boston, Massachusetts
Wendy L. Sydow
Camp Dresser & McKee Inc.
Annandale, Virginia
ABSTRACT
Remedial investigation/feasibility studies (RI/FS) are under-
taken to determine the nature and extent of the threat presented
by the release of hazardous contaminants which would cause sub-
stantial danger to present or future public health, welfare or the
environment. In these studies, scientists and engineers evaluate
remedial actions that would prevent or minimize contaminant
migration. Remedial investigations are comprised of data collec-
tion and evaluation activities which define sources of contamina-
tion and evaluate the extent of contamination. To ensure that the
data generated during the remedial investigation are adequate to
support a decision, a clear definition of the decision and the
method by which it will be made must be established early in the
planning of each RI/FS. These determinations are facilitated
through data quality objectives (DQOs) development.
DQO development is a dynamic process involving decision-
makers and project managers, with input from appropriate tech-
nical staff. The total uncertainty associated with these decisions
can be determined by evaluating data collected and analyzed in
conformance with the DQO process. Total uncertainty includes
both sampling error and analytical measurement error.
DQOs are established prior to data collection and are critical
in developing a sampling and analytical plan consistent with
CERCLA program objectives. DQOs are developed to address
the specific requirements of the individual sites and are based on
the intended uses of the data.
The DQO process assures the development of a formal plan de-
scribing the level and extent of sampling and analysis required
to produce enough data to evaluate the remedial alternatives for
a site. Site-specific DQOs are incorporated in sampling and analy-
sis plans. DQO development approach is presented here in order
to improve the overall quality and cost-effectiveness of data
collection and analysis activities in RI/FS activities.
INTRODUCTION
In order to ensure that the data generated during remedial in-
vestigations are adequate to support decisions regarding remedial
action at an uncontrolled hazardous waste site, these decisions
and the methods by which they will be made must be clearly de-
fined early in the planning of the remedial investigation/feasi-
bility study (RI/FS). Data quality objectives ensure that the en-
vironmental data collected to support an Agency decision are of
known and documented quality. These statements may be qual-
itative or quantitative and are specified prior to data collection
activities. DQOs are identified during the RI/FS scoping process
and during development of sampling and analysis plans.
Data quality objectives are developed through a three-stage
process illustrated in Fig. 1. Although the three stages are iden-
tified and discussed sequentially, they are undertaken in an inter-
active and iterative manner whereby all the elements of the DQO
process are continually reviewed and applied during the RI/FS.
DQOs are developed at the onset of an RI/FS project and revised
or expanded as needed based upon the results of each data collec-
tion activity.
STAGE 1—IDENTIFY DECISION TYPES
Stage 1 of the DQO process is undertaken to identify the in-
dividuals responsible for decisions, to identify and involve data
users and to define the types of decisions which will be made as
part of each site-specific RI/FS. The major elements of Stage 1
are presented in Fig. 2.
Identify and Involve Data Users
Although identification and involvement of data users is listed
as the first step in Stage 1 of the DQO development process, it is a
continual process throughout the RI/FS. As new information on
a site is gained, the specific areas of expertise required to com-
plete the RI/FS can be better defined.
The remedial project manager (RPM), as defined in the NCP
Section 300.6 (Federal Register 50 No. 224), is the federal official
designated by the U.S. EPA or another lead agency to coordi-
nate, monitor or direct remedial or other response activities under
the NCP. The RPM and the RI/FS contractor site manager are
the key decision-makers for the DQO development process. They
are responsible for ensuring that appropriate data users are in-
volved in the RI/FS process and that DQOs are developed. The
major responsibility for incorporating DQOs into planning and
implementation activities lies with the RI/FS contractor.
398 SITE REMEDIATION TECHNIQUES
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STAGE 1
IDENTIFY DECISION TYPES
• IDENTIFY & INVOLVE DATA USERS
• EVALUATE AVAILABLE DATA
• DEVELOP CONCEPTUAL MODEL
• SPECIFY OBJECTIVES/DECISIONS
STAGE 2
IDENTIFY DATA USES/NEEDS
• IDENTIFY DATA USES
• IDENTIFY DATA TYPES
• EVALUATE SAMPLING/ANALYSIS OPTIONS
• IDENTIFY DATA QUANTITY NEEDS
• IDENTIFY DATA QUALITY NEEDS
• SPECIFY PARCC GOALS
STAGE 3
DESIGN DATA COLLECTION PROGRAM
• ASSEMBLE DATA COLLECTION COMPONENTS
• DEVELOP DATA COLLECTION DOCUMENTATION
Figure 1
DQO Three-Stage Process
IDENTIFY I INVOLVE DATA USERS
EVALUATE
AVAILABLE DATA
DEVELOP CONCEPTUAL MODEL
- CONTAMINANT SOURCES
- MIGRATION PATHWAYS
- POTENTIAL RECEPTORS
• CONTAMINANTS OF CONCERN
SPECIFY OBJECTIVES/DECISIONS
Figure 2
DQO Stage 1—Identify Decision Types
Figure 3
Relationship of Data to Risk for Making a Decision
INCREASING
RISK OF
MAKING WRONG
DECISIONS
INCREASING DATA QUALITY/QUANTITY
Figure 4
Relationship of Risk and Data Quality/Quantity
Evaluate Available Information
Available site information is reviewed and evaluated as an
initial step in the RI/FS process. This review provides the foun-
dation for additional on-site activities and serves as the data base
for RI/FS scoping. Data should be evaluated at the initiation of
an RI/FS and at each stage within the RI where additional data
are obtained.
Develop Conceptual Model
The conceptual model provides a description of the uncon-
trolled hazardous waste site and its environs which is used to
develop hypotheses regarding the contaminants on-site, their
routes of migration and their potential impact on sensitive recep-
tors. Conceptual models may include components from computer
models, analytical models, graphic models and/or other tech-
niques. The hypotheses are tested, redefined and modified during
the course of the RI/FS. The conceptual model should be de-
tailed enough to address all potential or suspected sources of con-
taminants, types of contaminants and concentrations, affected
media, rates and routes of migration and receptors.
The conceptual model may be expanded as additional site in-
formation is obtained and, in some cases, may serve as the start-
ing point to develop a computer or statistical site model.
Specify RFI/FS Objectives
In a broad sense, the objective of an RI/FS is to determine
the nature and extent of the threat posed by the release or threat
of release of hazardous substances and to select a cost-effective
remedial action to minimize the risk of migration of or exposure
to contaminants. Achieving this broad objective requires several
complicated and interrelated activities, each having its own ob-
jectives, acceptable levels of uncertainty and attendant data qual-
ity requirements. The expression of these objectives in clear pre-
SITE REMEDIATION TECHNIQUES 399
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else statements is the first step toward the development of a cost-
effective program to collect sufficient data for decision-making.
This step of the DQO development identifies the decision-mak-
ing process, the decision types and any additional data needed to
complete an RI/FS.
Defining the types of decisions which will be made regarding
remedial actions for uncontrolled hazardous waste sites requires
a clear understanding of the problems posed by the site and an
awareness of the consequences of making a wrong decision. The
consequences of a wrong decision must be weighed for each
major decision made during the RI/FS process. Where the con-
sequences of a wrong decision carry significant public health,
safety or environmental impacts, greater attention must be paid
to obtaining the data required to ensure a sound decision.
The information available for making a decision is related to
the risk of making a wrong decision and the significance of the
consequences. As shown in Fig. 3, as the quantity and quality of
data increase, the risk of making a wrong decision decreases.
This is not a true inverse relationship; at some point, the collec-
tion of additional data or improvement of data quality will not
significantly increase overall data quality. This can be expressed
best on a graph (see Fig. 4). The risk of making a wrong decision
decreases as data quantity and quality increase until it reaches a
point of diminishing returns, where additional data or increased
quality of data do not significantly reduce the risk of making a
wrong decision.
Data quantity and data quality are independent variables which
must be considered jointly when assessing the consequences of
making a wrong decision. Collecting increased quantities of low
quality data may not reduce the risk of making a wrong decision.
Likewise, increasing the data quality of a limited number of sam-
ples may not add significantly to the body of knowledge to be
used in making a decision.
The value of obtaining additional data or increasing data qual-
ity traditionally has been based on professional judgment for
RI/FS projects. The intent of the DQO process is to support such
decisions with a more systematic approach to evaluating the risk
associated with wrong decisions and to determining the levels of
uncertainty associated with decisions.
As part of the development of the objectives for the RI/FS, the
decision-making process should be outlined. Specific decisions
that will be made, when they will be made and by whom they will
be made, are critical parts of the outline development. Critical
decisions need to be considered when defining the data to be col-
lected, the sampling and analytical methods, the sensitivities of
the methodologies and the method detection limits. The ade-
quacy of the data which will be collected during the RI/FS to
meet the overall project objectives must therefore be evaluated
in Stage 1 of the DQO process. The result of Stage 1 is a deter-
mination of the sufficiency of the existing data to meet the RI/FS
objectives. If the existing data are sufficient, there is no need to
collect additional data. If the data are insufficient, the types,
quality and quantity of data which must be collected will be de-
termined in Stage 2.
STAGE 2—IDENTIFY DATA USES/NEEDS
Stage 2 of the DQO process is undertaken to define specific
data uses and to specify the types of data needed to meet the RI/
FS objectives. The major elements of Stage 2 of the DQO pro-
cess are identified in Fig. 5.
Identify Data Uses
A detailed evaluation of data uses is undertaken in Stage 2 to
ensure that the amount of data (number of sampling points and
frequency of sampling) and quality of data (field sampling and
IDENTIFY DATA
USES
IDENTIFY DATA
TYPES
IDENTIFY
SAMPLING/ANALYSIS
OPTIONS
IDENTIFY
DATA QUALITY
NEEDS
IDENTIFY
DATA QUANTITY
NEEDS
SPECIFY
PARCC
GOALS
Figure 5
Stage 2—Identify Data Uses/Needs
analytical methods and method detection limits) are appropriate
for their intended use. Uses for these data can be developed by
evaluating the general use category for which data will be ob-
tained, such as health and safety, site characterization, risk assess-
ment, alternatives evaluation, remedial action design or potential-
ly responsible party (PRP) determination.
Data use categories define the general purposes for which data
will be collected during the RI. By defining the intended uses for
the data early in the RI scoping process, one can develop a con-
cise statement regarding the type of data needed.
Data Types
Data types may be specified initially in broad groups such as
background samples or media samples. Then the data may be re-
fined to a more detailed level to ensure that data obtained are use-
ful in meeting the objectives of the RI/FS. The process should
be followed for each medium of interest or each source material.
Completing the entire decision matrix results in specifying the
data type needed for each intended data use.
Since environmental media and source materials are interre-
lated at uncontrolled hazardous waste sites, data types used to
evaluate groundwater contamination can also be used to eval-
uate soil contamination. By identifying data types by medium,
the decision-maker and the data users can discuss overlapping
data needs to refine the scope of the RI.
The types of analyses which will be performed on each sam-
ple must be determined while identifying data types. The analyti-
cal requirements are dictated by the use of the data, which ulti-
mately is driven by the remedial alternative which is under con-
sideration.
The data types specified in Stage 2 not only should be limited to
chemical analytical parameters, but also should include physical
400 SITE REMEDIATION TECHNIQUES
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parameters such as permeability and porosity, which are needed
to evaluate contaminant migration. The level of detail to which
data types are defined during the DQO process must be sufficient
to evaluate sampling and analysis options during subsequent
DQO stages.
Evaluate Sampling and Analysis Options
One can evaluate sampling and analysis options only after all
components or subsets of the sampling and analysis options are
identified. The components of a sampling and analysis plan in-
clude the individual sample collection and analysis procedures
which will result in the data types specified. For example, to pro-
vide data on the concentration of volatile organics in a monitor-
ing well, one must identify sampling procedures which will result
in a representative sample and analytical methods which will yield
the desired results.
Developing a sampling and analysis approach, which ensures
that appropriate levels of data quantity and quality are obtained,
usually can be accomplished using a phased RI approach and field
screening or remote sensing spproaches to direct the data collec-
tion activities. By subdividing the data collection program into a
number of phases, the data can be obtained in a sequence which
allows them to be used to direct subsequent data collection activ-
ities.
The resources available to perform a RI/FS must be evaluated
during the scoping process. Within Stage 2 of DQO development,
the time, personnel resources and equipment required for obtain-
ing data are considered.
Cost savings can be achieved by performing multiple media
sampling activities simultaneously (e.g., sample groundwater and
surface water at the same time) or by separating sampling into
phases to better target sample collection. When considering per-
sonnel, one should determine if special training is required to
undertake certain field sampling or laboratory analysis tasks. This
evaluation is most effectively performed as sampling and analysis
options are identified.
Identify Data Quality Needs
Data quality needs can be identified best by establishing per-
formance and cost criteria. Performance criteria can be used to
establish action limits above which remediation or removal is
deemed necessary. Design criteria are used to determine if cost
estimates for remedial alternatives fall within acceptable ranges.
In specifying any criteria on which to base decisions, action
levels and the acceptable risks should be considered. The action
level specifies a concentration above which some action will be
taken. For example, an action level can be used during the FS to
make decisions regarding areas requiring remediation. Determin-
ation of action levels is currently a site-specific activity. The de-
cision-maker, with input from data users, determines the appro-
priate action level for the site. The acceptable risk specifies the
chance of exceeding the action level which is acceptable to the de-
cision makers.
U.S. EPA feasibility studies guidance1 states that the cost of re-
medial alternatives should be determined to within +50% and
-30% of the actual cost. This statement not only puts require-
ments on the type and amount of data which must be collected
during the field investigation, but also requires the decision-
maker to consider potential remedial alternatives before planning
the field investigation.
Identify Data Quantity Needs
The number of samples which should be collected for an RI
activity can be determined using a variety of approaches. The
validity of the approach utilized is dependent on the characteris-
tics of the media under investigation and the assumptions used to
select sample locations. The greater the quantity of data available
for making a decision, the higher the chances for obtaining data
which address the RI/FS objectives. In situations where data are
limited or unavailable, the RI should be developed in a phased
approach to allow collection of initial samples to characterize
the general conditions at the site. These data then can be used to
help select the appropriate number of samples to be obtained in
subsequent phases of the RI.
Specify PARCC Goals
Data quality requirements for a given program or activity can
be specified by using the precision, accuracy, representativeness,
completeness and comparability (PARCC) parameters.
PARCC goals should be developed based upon the level of cer-
tainty required in the data. Historical precision and accuracy data
for analytical laboratories being considered during the RI/FS
scoping process should be reviewed in order to evaluate adequacy
for intended use.
If the level of precision and accuracy historically generated by a
laboratory or particular test method is unacceptable, analysis of
additional matrix spikes and replicate analysis may be warranted
for the sampling and analytical task under consideration. PARCC
parameter goals are established in order to have a method to eval-
uate results. The actual precision, accuracy, representativeness,
completeness and comparability of the data can only be fully
assessed following collection of the data. If upon review of the
analytical data it is determined that the PARCC goals have not
been met, the decision-maker must decide if samples are suffic-
ient to make decisions or if re-sampling or re-analysis is war-
ranted. If the PARCC goals have been met, the resulting data
should be considered appropriate for the uses specified in the
DQO process.
STAGE 3—DESIGN DATA COLLECTION PROGRAM
Stage 3 of the DQO process is undertaken to develop and
assemble the detailed data collection program for the RI/FS.
Through the process of addressing the elements identified in
Stages 1 and 2, all the components required for completion of
Stage 3 should be available for compilation. Stage 3 entails assem-
bling the data and developing documentation.
The DQO development process is initiated during RI/FS scop-
ing and is completed in conjunction with the development of a
work plan, sampling and analysis plan and quality assurance pro-
ject plan (QAPjP) addressing each RI/FS phase. The various
stages of the DQO development process are interactive in nature.
As additional details regarding the site are discovered during the
scoping process, the decisions which will be made during the
RI/FS are further refined. This refinement of decisions allows
for further specification of data needs and for design of the data
collection program.
Assemble Data Collection Components
During Stage 2, specific DQOs have been developed by media
or sampling activity. The intent of Stage 3 is to compile the in-
formation and DQOs developed for specific tasks into a compre-
hensive data collection program.
The data collection components should be developed for all
sampling tasks and phases. During this process, a detailed list of
all samples to be obtained should be assembled in a format which
includes RI phase, media, sample type, number of samples and
QA/QC samples (type and number). In addition, a schedule for
all sampling activities should be developed in bar chart or critical
path method format.
Develop Data Collection Documentation
Developing DQOs in a formal manner ensures that the appro-
priate data are obtained in order to meet the objectives of the
RI/FS. Data collection documentation requirements vary on a
SITE REMEDIATION TECHNIQUES 401
-------
regional basis within the U.S. EPA RI/FS program. The output
of the RI/FS DQO process is a well defined sampling and analy-
sis plan based on data needed to make decisions. The DQO pro-
cess also will allow the scope and costs for work plans to be devel-
oped on a sound decision-based approach.
CONCLUSIONS
The DQO process provides a framework to ensure that all the
pertinent issues related to data collection are addressed. Through
the process of developing DQOs, the level of uncertainty asso-
ciated with a data set can be established. RI/FS data are collected
for a variety of uses and data of differing qualities are required
for each specific use. The highest quality obtainable data seldom
are required for all activities. What is required, however, is that
the quality of all data collected be known and documented. This
procedure allows the most efficient use of resources by defining a
given data quality need and selecting an analytical support option
that, when integrated with a specific sampling approach, will pro-
duce data of the quality needed. By determining the quality of the
data which have been collected, the decision-maker can draw con-
clusions and make decisions with a specified degree of certainty.
Additional information about DQOs may be obtained from guid-
ance under development by the Office of Solid Waste and Emer-
gency Response.1
REFERENCES
1. U.S. EPA, "Guidance on Feasibility Studies Under CERCLA,"
Office of Research and Development, Cincinnati, OH; Office of
Emergency and Remedial Response, Office of Waste Programs En-
forcement, Office of Solid Waste and Emergency Response, Wash-
ington, D.C., EPA/540/G-85/003, 1985.
2. U.S. EPA, "Data Quality Objectives Development Guidance for Un-
controlled Hazardous Waste Site Remedial Action Programs" (draft),
Office of Emergency and Remedial Response, Office of Waste Pro-
grams Enforcement, Office of Solid Waste and Emergency Response,
Washington, DC, OSWER Directive 9355.0-7A. Unpublished.
402 SITE REMEDIATION TECHNIQUES
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An Approach to Remediating
Contaminated Bedrock Aquifers
Peter J. McGlew
Camp Dresser & McKee Inc.
Boston, Massachusetts
ABSTRACT
A major problem to the restoration of abandoned hazardous
waste disposal sites relates to the remediation of contaminated
bedrock aquifers. A critical element in the successful remedia-
tion of these aquifers is the ability to identify and evaluate migra-
tion pathways through the bedrock. There are a variety of ana-
lytical procedures that the geologist/engineer can employ to assist
in identifying these principal migration pathways. These available
tools will be identified through a series of site specific case studies.
The basis for developing the migration pathways lies in the con-
duct of well-structured field investigation programs including the
application of specific geophysical techniques. The information
gathered during the geophysical survey is then employed to both
supplement and direct the boring and monitoring well installa-
tions.
The data collected during the initial field investigation are used
to construct three-dimensional rock block diagrams necessary to
design the pumping test required to verify fracture patterns within
the aquifer system. The proper location of fracture sets including
information upon interconnection is then employed to evaluate
aquifer response characteristics under different groundwater ex-
traction scenarios.
The verification of the aquifer response characteristics under
localized pumping is the first step in the successful development
of a groundwater remediation program for bedrock contamina-
tion.
INTRODUCTION
The approach to the hydrogeologic investigation and subse-
quent remediation of the contaminated aquifer depends on the
physical characteristics of the site. Two sites, referred to as Site 1
and Site 2, have varying physical characteristics. Therefore, a
variety of geophysical techniques were used to obtain the struc-
tural and hydrologic data necessary to define contaminant
migration pathways within the bedrock aquifers.
The hydrogeologic investigations at these sites were conducted
in phases, each built upon the information from the previous
phase. In Phase I of any hydrogeologic investigation, all prev-
ious reports, studies, maps, aerial photos and records are re-
viewed. The least costly Investigative techniques that will provide
useful information are conducted in Phase I of the field investiga-
tion; the following techniques frequently are used to provide
some site specific data for relatively little expense:
• A fracture trace analysis to determine the primary and secon-
dary fracture orientations as well as the type of bedrock at the
site
• A seismic refraction survey, which will provide the depth to the
water table, the thickness of various lithologic units and the
topography of the bedrock underlying the site
• Sampling and analysis of existing wells or potential contam-
inant source areas to evaluate the magnitude of the contamina-
tion problem at the site
• Geophysical logging (i.e., resistivity, caliper, temperature,
conductivity and self-potential) of existing boreholes on-site
to provide information on the depth of fracturing, rock quality
and zones that transmit water
The Phase I results of the hydrogeologic investigation are used
to analyze the various physical characteristics at the site in order
to design the appropriate Phase II investigation. The objective of
this phase is to collect the necessary data to construct a three-
dimensional rock 'block diagram of the site. The rock block dia-
gram is based on data from the installation, sampling and analy-
sis of monitoring wells and the results of more complicated and
costly geophysical surveys, which may include the following:
• Acoustic televiewer logging, which provides information on
the depth and orientation of fractures within the borehole
• Vertical seismic profiling, which provides information on the
depth, orientation and hydraulic conductivity of the fractures
• Geotomography (cross borehole electro magnetics), which pro-
vides information on the depth and orientation of fractures be-
tween the boreholes
• Oriented drilling, which provides information on the rock type
and quality as well as the depth and orientation of the fractures
intersecting the borehole
It is important to note that the above geophysical techniques
yield similar information. The decision whether to use one of
these or other techniques will be determined by the physical char-
acteristics at the site and the Phase I data collected. Both vertical
seismic profiling and geotomography provide data on fracture
orientation some distance away from the borehole, while the
acoustic televiewer does not. The acoustic televiewer, however,
was used at Site 1 because Phase I information revealed that the
fractures were steeply dipping which lowers success with vertical
seismic profiling (a refraction technique). The acoustic teleview-
er was less empensive than the geotomography at this site.
At Site 2 there were more data and information available per-
taining to the site; the upper zone (0-20 ft) of the bedrock was
highly weathered and fractured. Thus, the bedrock aquifer was
capable of transmitting water as a porous medium would. Due
to a breakdown of the acoustic televiewer, pumping and packer
testing were used to help determine the contaminant migration
pathways in the bedrock aquifer at Site 2.
Phase III relies on the contamination information, bedrock
geology, hydrogeologic information and rock block diagram to
SITE REMEDIATION TECHNIQUES 403
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indicate the appropriate locations to conduct pumping tests.
The pumping tests verify the major fracture sets within the
aquifer as well as the interconnection of these fracture sets. The
information on the interconnection of fracture sets is employed
to evaluate aquifer response characteristics under different
groundwater extraction scenarios. The various extraction scen-
arios are used to develop a successful groundwater remediation
program for the contaminated bedrock aquifer.
HYDROGEOLOGIC INVESTIGATION RESULTS
FOR SITE 1
The Phase I investigation revealed that dumping of bulk liquids
took place in two general locations 0.5 mile apart. High levels
(up to 10 ppm) of volatile organic compounds were found in the
overburden and bedrock aquifers in these areas as shown in Fig.
1. A bedrock supply well for an apartment complex, which is
located in a direction perpendicular to the flow gradient, became
contaminated.
The bedrock in the study area consists of a meta sedimentary
schist with a low porosity and permeability. The estimated
hydraulic conductivity varies from 1 x 10 ~5 to 1 x 10 ~7
(cm/sec), which indicates that flow through the rock would be in-
significant. Thus, the major flow of groundwater must be
through the fracture system. The major fracture sets in the area
trend N 57 E and are nearly vertical. A major structural feature
in the area is a fault that passes close by the site which is oriented
in a N 50 E direction. This fault caused the sympathetic fractur-
ing of the formation at the site, i.e., the fractures on-site are sim-
ilar in orientation to the nearby fault. Schistose rocks contain
planes of weakness paralleling foliation which promotes fractur-
ing and erosion. Thus, zones of higher conductivity often lie
parallel to the foliation. The foliation was found to trend north-
east at the site. Results from the geophysical logging indicated
that the majority of the fracturing and water bearing fractures
are located in the upper 100 ft in the bedrock aquifer. This find-
ing saved costs in the drilling of Phase II monitoring wells because
they were required to reach a depth of 100 ft rather than 300 ft,
which was the depth of the previously installed wells. Results
from the seismic refaction survey indicated the bedrock to be at a
depth of 2 to 30 ft across the site with a water table sloping slight-
ly to the south and southeast. The velocities were as expected for
a schist, but the defining of a uppermost weathered zone was
difficult due to the thin layer of basal till overlying the bedrock.
Phase II of the investigation consisted of strategically locating
additional monitoring well clusters, logging them with an acoustic
televiewer with further sampling and analysis of the on-site
groundwater. The results indicated a potential for the bedrock
supply well serving the apartment complex to be interconnected
with one of the source areas. It was anticipated that the pump-
ing of a deep bedrock well in the vicinity of the second source
area would control the groundwater flow in the vicinity of this
source area. Widespread contamination from volatile organic
compounds was found predominantly in the bedrock aquifer as
shown in Fig. 1. A rock block diagram was developed that delin-
eated promising locations at which to conduct pumping tests.
Phase III consisted of the results of two pumping tests and an
additional sampling round of on-site groundwater. The pump test
data suggested linear flow in a fractured rock aquifer, where the
pumped fracture acts much like a collector well. The drawdown
is not radial, but there is a trough-like depression in the water
table parallel to the pumped fracture as shown in Fig. 2. It was
verified that the areas of contamination in the bedrock could be
controlled by pumping two rock wells. The flow in the bedrock is
controlled by fracture sets oriented northeast southwest, although
the horizontal gradient is to the south and southeast. The troughs
of depression created by the two pumping tests are oriented
northeast, which coincides with the fault in the site area and frac-
ture trace analysis. Even during non-pumping conditions, the
contaminants were found to migrate from northeast to south-
west. The information collected indicates that a pumping and
treatment scenario at the southwest deep rock well in Source Area
2 could be readily implemented. Appropriate remedial action in
connection with contaminated soils would shorten the opera-
tional time frame for such remedial action.
Figure 1
Site Map Indicating Estimated Source Areas of Contamination
and Location of Selected Pumping Wells
Figure 2
Trough Like Depression Created in Potentiometric Surface in the
Vicinity of a Fracture
404 SITE REMEDIATION TECHNIQUES
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HYDROGEOLOGIC INVESTIGATION RESULTS
FOR SITE 2
The Phase I investigation revealed that dumping of bulk
liquids, landfilling of drums, sludges, construction debris and
tires took place in a highly permeable (sand and gravel) kame de-
posit. The stratified drift (kame) deposits are located in the low-
lands between north-south oriented highlands.
The bedrock in the study area consists of a meta-sedimentary
gray colored gneiss. A diorite dike which trends north-south
along the eastern border of the site was identified in previous
bedrock maps as shown in Fig. 3. In general, the bedrock ex-
hibits a north-south fracture pattern. In the vicinity of the site
west of the dike, the fractures dip 30° to the east. To the east of
the dike, a contact between the formation underlying the site and
a younger formation is indicated. This younger formation has
fractures dipping steeply to the west.
Past studies indicated a flow to the north in both the over-
burden and bedrock aquifer from the land disposal area. The
bedrock was highly fractured and weathered, providing the
majority of groundwater from the upper 20 to 40 ft of the rock.
The upper zone of rock had a similar porosity and hydraulic
conductivity to that of the porous medium such as a fine sand.
Gneiss is similar to a shist; the zones of higher conductivity often
lie parallel to the foliation, which trend north-south at the site.
The seismic refraction survey results indicated that the rock was
highly weathered and was at a depth of 5 to 25 ft below ground
surface. The water table slope was to the north then east away
from the land disposal area. The dike registered a high velocity
indication that it has a competent surface with little weathering
or fracturing.
A ground penetrating radar investigation revealed several areas
of buried drums and the delineation between the disturbed and
undisturbed soil boundaries. In addition, a magnetometry sur-
vey was conducted to determine the exact location of the diorite
dike and locate potential fracture zones in the gneiss which could
serve as contaminant migration pathways. The dike exhibited
600 gamma (a unit of magnetic flux) differences above that of
the earth's total magnetic field. The instrument used is capable of
determining a one gamma difference and was easily capable of
mapping out the diorite dike, which contains mafic minerals.
Phase II of the investigation consisted of strategically locating
additional monitoring wells to the west, to the east and directly
in the dike. Short duration pumping and packer tests were per-
formed in four rock wells. The sampling and analysis of the en-
tire monitoring well network was conducted to determine con-
taminant movement through the aquifer over time. Since a prev-
ious investigation had been conducted, only two phases of this
investigation were required to construct a rock block diagram
and perform pumping tests to verify the fracture patterns on-site.
The results of Phase II of the investigation indicate that the
dominant feature impacting groundwater flow is the diorite dike
bordering the east side of the valley in which the site is located.
The general direction of groundwater flow for the overburden
and bedrock aquifer at the site is shown in Fig. 4. Note that the
groundwater table to the west of the dike has a low water table
gradient of 0.005 ft/ft. This gradient results from the dike retard-
ing the groundwater flow and the flat topography of the valley
floor, which causes a back water west of the dike. East of the
dike, the groundwater gradient is (0.025 ft/ft), five times that
west of the dike.
'. SCALE IN FEET
Groundwater
Flow Direction "il^
Figure 3
Site Location in Relation to the Dike
Figure 4
Groundwater Elevation Contours in Bedrock
SITE REMEDIATION TECHNIQUES 405
-------
The hydraulic conductivity (K) estimated in several bedrock
wells west of the dike exhibited higher values than the kame de-
posits. Most of the groundwater in the bedrock aquifer is derived
from the upper 50 ft in many of the on-site monitoring wells. A
well drilled approximately 90 ft into the dike had the lowest K of
all the wells on-site and was only producing 8 gal/day.
Pumping test results from two bedrock wells did not display
the linear drawdown but a radial drawdown that occurs in a
permeable sand and gravel deposit or highly fractured and porous
bedrock.
The contaminants were found migrating from the land disposal
ar.ea north then eastwards toward the bedrock dike (Fig. 4). Mod-
erate levels of total volatile organics (less than 1 mg/1) were found
in groundwater at the western edge of the dike. A low level
(approximately 40 ug/1) of total volatile organics was found in
one bedrock well east of the dike. Groundwater and contam-
inants can migrate through and over the dike, but the dike has
retarded the migration considerably due to its low K and location
in the valley.
This information indicates that a groundwater pumping and
treatment scenario could be implemented west of the dike as a
remedial action. Appropriate remedial action in connection with
the contaminated soils would shorten the operational time of such
remedial action.
CONCLUSIONS
Sites 1 and 2 were selected as examples because of the substan-
tial differences in the migration of contaminants from the source
areas due to the physical characteristics of the sites, especially
the bedrock geology.
At Site 1 contamination of the groundwater was caused by im-
proper land disposal of hazardous waste liquids. The flow of
groundwater is controlled by the major fracture sets within the
site area oriented northeast-southwest. This results in a flow per-
pendicular to the flow potential (hydraulic) gradient in the over-
burden aquifer. The investigation focused on determining the
depth of water bearing fractures and their orientations via a frac-
ture trace analysis, geophysical logging of the wells and two
pumping tests. The data from the investigation indicated that the
contamination in the rock could be controlled by pumping two
deep rock wells that were installed in the fracture sets which inter-
sect the source areas of contamination.
At Site 2 the groundwater contamination was caused by im-
proper land disposal of hazardous waste. The groundwater flow
is strongly influenced by the location of a diorite dike that
borders the eastern side of the valley in which the site is located.
The groundwater flow direction in the upper bedrock is similar
to that of the overburden. This conclusion was substantiated
by the results of pumping tests and a bedrock groundwater eleva-
tion contour map of the site. The investigation focused on de-
termining the effects of the bedrock geology on the groundwater
flow and contaminant transport via above ground geophysical
surveys (ground penetrating radar, electromagnetics and seismic
refraction) and down well geophysical techniques (pumping and
packer tests and pumping and recovery tests). The results from
these investigations indicate that contaminants flow with the
groundwater north then east from the land disposal area. The
transport of contamination in the bedrock through the dike is
significantly retarded due to its lower permeability. In addition,
to the west of the dike, the contamination is contained in an area
with little vertical or horizontal hydraulic gradients that drive the
flow. The results of this investigation indicate that the implemen-
tation of a pumping and treatment scheme west of the dike is
viable to contain and treat the contaminated groundwater leav-
ing the source area.
406 SITE REMEDIATION TECHNIQUES
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Impact of the New Superfund
On the Remedial Action Program
Gregory A. Vanderlaan
U.S. Environmental Protection Agency
Chicago, Illinois
D. Brint Bixler
CH2M HILL
Reston, Virginia
ABSTRACT
This paper reviews the proposed cleanup provisions of Super-
fund reauthorization. A brief overview of the existing Superfund
remedial program is provided as background. Reauthorization
provisions that will impact the current program are reviewed and
specific technical requirements are discussed. Topics covered in-
clude preferences for permanent technologies and use of alterna-
tives to land disposal, applicability of Federal and state require-
ments for on-site actions and requirements for acceptable off-site
facilities. When appropriate, impacts of the new technical re-
quirements are summarized.
INTRODUCTION
In the first 5 years of the Superfund program, the U.S. EPA
was faced with a major national environmental problem—protec-
tion of public health and the environment from hazardous
substances found at uncontrolled hazardous waste sites. Armed
with the new statutory authority of CERCLA, the U.S. EPA im-
plemented a program to prioritize the worst sites, investigate their
threats, evaluate and select cost-effective remedial actions and
design and undertake cleanup. To do this, the U.S. EPA
developed a response program that combines Federal, state and
private sector resources. A variety of complex technical, legal and
policy issues had to be dealt with. Engineers and scientists in the
government and private sectors have brought together expertise in
disciplines such as hydrogeology, toxicology, risk assessment, en-
vironmental modeling, process engineering and regulatory
analysis.
Thus far, the Superfund effort has resulted in listing over 800
sites on the National Priorities List (NPL), remedial investiga-
tions and feasibility studies (RI/FS) at over 400 sites and cleanup
projects at 47 sites, Response activity will be shifting from the
study phase to the cleanup phase as RI/FS are completed and
more sites are ready for cleanup.
When the original Superfund legislation was passed in 1980,
Congress and the U.S. EPA recognized that the $1.6 billion fund
established for cleanup was inadequate to deal with the magni-
tude of the nation's uncontrolled hazardous waste site problem.
For the past 2 years, Congress has been working to draft revised
legislation needed to replace the original CERCLA after its taxing
provisions expired in late 1985. A number of complicated issues
are being addressed during Superfund reauthorization, including:
• Size of the fund
• Source of revenue for the fund
• Requirements for the remedial program
• Cleanup standards
• Standards and scheme for liability
The long and complicated reauthorization process extended
beyond expiration of CERCLA and, at the time of this writing, is
still continuing. A number of issues have been resolved by a
House and Senate conference committee, and reauthorization is
expected in the near future.
Size of the Fund/Mandatory Schedules
This paper focuses on the potential new technical requirements
that will impact the conduct of remedial investigations and
feasibility studies at Superfund sites. A brief summary is
presented first of some related provisions that have been agreed to
by the conference committee including the size of the fund and
mandatory schedules of program activities. This background will
be helpful to fully assess some of the impacts that specific
technical changes could have on the remedial program.
Reauthorization will increase the original Trust Fund level of
$1.6 billion to a level of $8.5 billion over 5 years. Coupled with
the increased funding level is a requirement for the U.S. EPA to
achieve mandatory schedules for a number of program targets
(Table 1). The U.S. EPA has been expanding its current program
capacity to anticipate this increased schedule of activities. How-
ever, the effort required to meet the proposed mandatory
schedules will be increased as a result of incorporating new
technical provisions into the current remedial process. These
schedules will create new challenges for managers in both the gov-
ernment and private sectors responsible for implementing the pro-
gram. The following section summarizes some of the proposed re-
authorization provisions (hat could modify the current process.
Table 1
Mandatory Schedules
• All preliminary assessments completed by Jan. 1, 1988
• All site inspections completed by Jan. 1, 1989
• Start 275 new RI/FS within 3 years
• Start a total of 650 new RI/FS within 5 years
• Start 175 new remedial actions within 3 years
• Start 200 new remedial actions during years 4 to 5
Note: All references to time frames are from date of enactment of reauthorization.
SUMMARY OF PROPOSED
CLEANUP PROVISIONS
Background of Existing Program
Several provisions of the original CERCLA and implementing
regulations promulgated in the National Contingency Plan (NCP)
are reviewed here to lay the framework for evaluation of potential
new requirements of Superfund reauthorization. The original
CERCLA (of 1980) provides limited direction regarding selecting
remedial actions. A remedial action is defined as an action consis-
tent with permanent remedy that prevents or minimizes the actual
SITE REMEDIATION TECHNIQUES 407
-------
or potential release of hazardous substances.
Remedial actions should prevent substantial danger to present
or future public health, welfare or the environment. In addition,
off-site disposal of hazardous substances is allowed only if certain
determinations are made, thereby creating an implied preference
for on-site response. Remedial actions are required to be consis-
tent with the NCP to the extent practicable, to be cost-effective
and to provide protection of public health, welfare and the en-
vironment.
CERCLA also requires off-site disposal to be at facilities in
compliance with the Solid Waste Disposal Act (i.e., RCRA).
However, the Act did not specify cleanup requirements for on-site
response actions.
The NCP promulgated on July 16, 1982, established a response
framework by describing the steps for setting priorities among
sites, taking emergency (removal) actions and evaluating remedial
actions. The NCP defined cost-effectiveness in terms of the "least
cost" alternative providing adequate protection to public health,
welfare and the environment. However, for a number of reasons,
the NCP did not provide direction on the extent or level of
cleanup attained by remedial actions.
As the U.S. EPA gained experience with remedial actions, the
NCP was revised and additional guidance was provided on re'
medial investigations and feasibility studies. The general effect
was to begin moving the program, away from the "least cost" ap-
proach which often favored containment or land disposal and
toward increased use of treatment and destruction technologies.
The revised NCP dated Nov. 28, 1985, modifies the previous
definition of cost-effectiveness by explaining that cost is only one
of several factors to be considered when selecting a remedy. This
provision allows the selection of potentially more expensive treat-
ment alternatives that provide better long-term protection and ef-
fectiveness than other alternatives such as land disposal. The
revised NCP also set a requirement that remedial actions generally
be consistent with the requirements of other environmental laws.
The Superfund reauthorization provisions on cleanup require-
ments adopted by the conference committee take the U.S. EPA
policy a step further. These provisions mandate specific require-
ments for selecting remedial actions and providing direction on
how the U.S. EPA is to conduct the technical evaluation of
remedial alternatives.
New Legislative Requirements
Superfund reauthorization will provide substantially more
detail than the original legislation. Proposed statutory language
includes a number of new technical requirements and incor-
porates requirements of the revised NCP in the areas of:
• Encouragement and use of treatment technologies or perman-
ent technologies
• Factors for evaluating alternatives
• Application of Federal and state standards
• Acceptability of off-site disposal facilities
• Involvement of the state in decision-making
A number of the new provisions are consistent with current
U.S. EPA procedures and, therefore, will not result in significant
program impacts. However, others may require basic changes in
the Superfund program. For example, decision rules related to
remedy selection and cost-effectiveness will encourage the use of
treatment technologies as alternates to land disposal without
treatment.
Remedial actions must still be cost-effective and consistent with
the NCP, to the extent practicable. However, a hierarchy of
preference for remedies is established. Remedies that use treat-
ment technologies that permanently and significantly reduce the
volume, toxicity or mobility of contaminants are preferred over
other alternatives. When treatment technologies are practicable
and available, off-site disposal without treatment is the least-
favored alternative. The selected remedy must still be protective
of human health and the environment. But it must also use per-
manent solutions and alternative technology or resource recovery
to the maximum extent practicable. These decisions rules are sum-
marized in Table 2.
Table 2
Summary of Decision Rules for Remedial AcUoni
• Remedy must b< cost-effective and consistent with the NCP to ex-
tent practicable
• Remedy must protect human health and environment
• Preference for permanent and significant reduction of contaminants'
volume, toxicity and mobility
• Utilize permanent solutions, treatment or resource recovery to maxi-
mum extent practicable
• Off-site land disposal without treatment is least-favored if treatment
is practicable and available
• Technologies need not be demonstrated at sites with similar charac-
teristics
Remedial investigations and feasibility studies will have to
evaluate alternatives using at least the factors listed in Table 3.
This provision may require modification of the RI/FS process to
evaluate alternatives in a different way. Increased emphasis will
be placed on attempting to assess long-term impacts of contain-
ment or land disposal in more detail than has sometimes been the
case in the past. Use of bench or treatability studies will increase
in order to evaluate how effectively treatment technologies reduce
contaminant volumes, toxicity and mobility.
Table 3
Remedy Evaluation Factors
• Long-term uncertainties of land disposal
• Requirements of RCRA
• Persistence, toxicity, mobility and ability to bioaccumulate
• Short- and long-term potential adverse health effects and exposure
• Long-term maintenance costs
• Potential future costs if a remedy fails
• Potential threats from process of off-site disposal or containment
To assess the impacts of new provisions in more detail, it is
useful to divide remedial actions into on-site and off-site actions.
The following sections will describe potential statutory changes
and, when possible, attempt to identify potential impacts on the
remedial program.
ON-SITE RESPONSE REQUIREMENTS
Applicable Cleanup Standards
Current U.S. EPA policy requires that on-site remedial actions
should comply with the legally applicable and relevant or ap-
propriate requirements of other Federal environmental laws.
Limited exceptions from compliance are allowed under specific
situations. The revised NCP lists the Federal requirements that
may be applicable or relevant and appropriate. For on-site
remedial actions, the major practical impact has meant use of
RCRA regulations and guidance to formulate and select alter-
natives.
Proposed reauthorization language will use a similar approach
requiring that remedies attain a level of control required by legally
applicabale or relevant and appropriate requirements with respect
to the specific site situation. Both Federal and state standards, re-
quirements, criteria or limitations are included. Federal standards
from the following laws are specifically listed:
408 SITE REMEDIATION TECHNIQUES
-------
• Toxic Substances Control Act
• Safe Drinking Water Act
• Clean Air Act
• Clean Water Act
• Marine Protection, Research and Sanctuaries Act
• Solid Waste Disposal Act (i.e., RCRA)
Any state-promulgated standard, requirement, criterion or
limitation that is more stringent than a Federal provision also
would apply if the state identifies it to the U.S. EPA in a timely
manner. This would include state facility siting laws or laws which
implement approved, authorized or delegated Federal programs.
Current U.S. EPA policy is to consider more stringent state re-
quirements as part of the selected remedy. This new provision
would formalize that policy and probably mean that remedial in-
vestigations and feasibility studies would have to incorporate
more stringent state requirements together with Federal re-
quirements into remedial alternatives. This provision would re-
quire states to identify their requirements to the U.S. EPA early
in the remedial planning process, preferably during the RI/FS
scoping phase.
Surface and Drinking Water
Applicable or relevant and appropriate requirements also in-
clude use of Recommended Maximum Contaminant Levels
(RMCLs) and Water Quality Criteria. Water Quality Criteria
have been used in the remedial program to set surface water
cleanup targets and, when adjusted to reflect only human con-
sumption, for groundwater cleanup. Therefore, requiring their
use should not be inconsistent with current procedures.
However, RMCLs, which are solely health-based indicators,
generally have not been used to set cleanup targets. Rather, Maxi-
mum Contaminant Levels (MCLs), which have somewhat higher
values based on technical and costs considerations, typically have
been used when available. Since some proposed RMCLs for car-
cinogens are set at zero, this requirement may be difficult or ex-
pensive to achieve using available technology.
Alternate Concentration Limits
Another potential impact on groundwater remedies deals with
setting alternate concentration levels (ACLs). Generally, ground-
water cleanup levels will be defined by applicable or relevant and
appropriate Federal and state requirements as described above.
These levels (e.g., MCLs) must be obtained at the facility boun-
dary defined by the RI/FS. Proposed statutory language will
allow alternate concentration levels to be set beyond the site
boundary under limited situations. All of the following condi-
tions must be met to establish an ACL under Superfund:
• There is a groundwater discharge to surface water
• There will not be a statistically significant increase in surface
water concentration as a result of the discharge
• Enforceable groundwater use restrictions will be provided be-
tween the site and surface water discharge
Congress indicated that the RI/FS should collect sufficient
background and surface or groundwater data to estimate poten-
tial surface water concentrations at a 95% confidence limit.
Potential health and environmental impacts from sediments and
biota also must be evaluated as part of the ACL process. It is like-
ly that remedial investigation data needs at some sites will be in-
creased to adequately evaluate these requirements. However,
these impacts should be limited to sites where surface water is
reasonably close to the source of contamination and there is no
current or projected groundwater use.
Review o'f On-site Remedies
If a remedial action will leave contamination on-site, the U.S.
EPA must review the site at least every 5 years to determine if ad-
ditional response is needed. A list of these sites must be prepared
and reported to Congress. This requirement is intended to allow
the U.S. EPA to fund either remedial or emergency response in
the event that a remedy fails or is less effective than anticipated.
Waivers from Applicable or Relevant
and Appropriate Requirements
The U.S. EPA's current policy allows for exceptions from com-
pliance with applicable or relevant and appropriate requirements
under specific situations. These situations have been specified in
the revised NCP. The existing exception used most frequently to
date is based on the action being an interim remedy that will be
part, of a total remedy not yet completed. Many sites will have
several approved remedies dealing with different areas or media
(e.g., contaminated soil and contaminated groundwater). The in-
terim remedy exception assumes that the final remedy selected in
the future would need to be consistent with other environmental
requirements unless another exception were approved at that
time. It appears that Congress intends to adopt most of the U.S.
EPA's current exceptions and will add additional ones. The pro-
posed exceptions are summarized in Table 4.
Table 4
Exceptions for On-Site Remedies
• The remedy is part of a total remedy that will ultimately comply
• Compliance will result in greater risk to human health and the en-
vironment
• Compliance is technically impracticable based on engineering con-
siderations
• The selected remedy will obtain an equivalent standard of per-
formance
• Compliance will not provide a balance between protection at the site
and the amount in the fund
• For state requirements, the state has not applied or demonstrated the
intention to apply the requirements consistently at other similar sites
Potentially the most significant new exception is one that
allows an equivalent standard of performance. It appears that this
exception would allow flexibility when selecting technologies that
could otherwise be required by a Federal or state law, standard or
requirement. For example, a state policy may require incineration
for organics removal in soil; however, a soil washing and treat-
ment process could be used if the same level of protection were
achieved. This exception will not allow a lesser level of protection
or a different method of calculating the level. If a standard is
technology based, a new performance level cannot be calculated
using a risk-based approach, on the assumption that it would
result in a lesser level of protection.
Permits
The U.S. EPA's current policy is that Federal environmental
permits are not required. Proposed statutory language goes fur-
ther by stating that no Federal, state or local permits are required
for on-site remedies (or other response actions). Since this is not
limited to environmental permits, it presumably includes all per-
mits including local building permits. The intent of this is to save
time required for permit processing while assuring that the ap-
propriate technical requirements are met through provisions
described above.
OFF-SITE REMEDIES
Use of Acceptable Facilities
The U.S. EPA's current policy is to require that off-site
facilities receiving waste from Superfund sites have all ap-
propriate permits and that the unit receiving the waste does not
SITE REMEDIATION TECHNIQUES 409
-------
have significant RCRA violations or conditions that could result
in improper operation of the unit. In practice, each RI/FS will
evaluate the type of treatment, disposal or storage appropriate for
the site-specific wastes and identify potential facilities. The final
decision on the acceptability of a facility generally is made by the
U.S. EPA Regional Office during the design phase, after the
remedy has been selected. The specific facility often will not be
identified until bids have been received and evaluated.
The new provision would require that any contamination
transferred off-site would be taken only to facilities in compliance
with RCRA, TSCA or other Federal or state requirements. Land
disposal is allowed only at a unit that is not releasing contamina-
tion to groundwater, surface water or soil. Any release of con-
taminants from any units at the facility must be controlled by an
approved RCRA corrective action program.
This provision appears to limit land disposal to facilities that
are fully in compliance with RCRA. Disposal at a unit specially
constructed for Superfund waste is not allowed if other existing
units are leaking and are not under corrective action. The U.S.
EPA is required to notify the facility owner regarding the
facility's suitability under these provisions, and the owner is
allowed to meet with the U.S. EPA to discuss any findings.
This new provision is essentially consistent with the U.S. EPA's
current policy and therefore should not create a significant new
program requirement. It appears likely that increased effort to
evaluate the acceptability of potential off-site facilities will have
to be made during the RI/FS. This provision may create tem-
porary problems with finding acceptable land disposal facilities
that do not have releases from any units or have all such releases
under approved corrective action programs. The U.S. EPA's ex-
perience shows that the number of acceptable facilities is limited
in some geographical areas. The possibility for delays in im-
plementation of the remedy may be increased while acceptable
facilities are identified.
Land Disposal Within a State
Several specific requirements are imposed for remedial actions
that involve land disposal within the state where a site is located.
These requirements only apply if land disposal is part of a remedy
that does not permanently and significantly reduce volume, toxic-
ity or mobility of the contaminants. In these situations, the
remedy used need not comply with a state requirement that could
prohibit land disposal in the state. In essence, this provision rein-
forces the preference for use of technologies that achieve perma-
nent and significant reduction of contamination. However, there
are several exceptions that would allow a state-wide prohibition of
land disposal to be effective. These are:
• The state requirement is generally applicable and was formally
adopted
• The requirement is based on relevant considerations and was
not intended to preclude on-site remedies or for other reasons
not related to public health and the environment
• The state must arrange for and pay for the additional .cost of
using a land disposal facility
All of these conditions must apply to allow a state land disposal
restriction. However, the condition requiring the state to pay for
the additional cost of using an out-of-state facility probably will
be the practical consideration.
CONCLUSIONS
Potential Impacts on the Remedial Process
This paper has discussed a number of potential new technical
provisions that may be required by Superfund reauthorization.
When considered individually, each has varying impacts on the
current remedial program. Some provisions are consistent with
current U.S. EPA policies and therefore will have no impact,
while others will require the program to move in new directions.
The impacts can be summarized in two general areas: (1) impacts
on the remedial investigation and feasibility process; and (2) im-
pacts on the types of remedial actions selected.
Impacts on the remedial investigation and feasibility study pro-
cess will result in procedural changes that translate to cost and
time impacts. Table 5 summarizes some of the potential impacts
on RI/FS. Overall, there should be an increase of both the cost
and time of RI/FS due to the need to conduct treatability studies
for alternate or permanent technologies and to comply with more
stringent state requirements. The extent of these increases is dif-
ficult to assess without implementation experience, but likely will
be proportional to the complexity of site considerations such as
number and type of contaminants, contaminated media and
availability of proven treatment technologies.
Table 5
Potential RI/FS Impacts
Provision
Time
Potential Impact
Cort
Revued Cost- Some increase due to Some increase due to
Effectiveness more extensive alternatives more extensive alter-
Procedures evaluation natives evaluation
State Standards Some delay for notification Increase cost to com-
of the U S EPA ply with more
stringent standards
Alternate Increase 10 collect addi- Increased data col-
Concentration tional field data at some lection and evaluation
Limits sites costs
On-site Permits Decrease since no permits No change
are needed
Off-site Facilities Minimal increase since Minimal or no
requirements are consistent increase
with current policy
Preference for Increase to lest applica- Increased cost of
Permanent Remedies bility of technologies treatability studies
and evaluations
Increased costs of
selected remedies
The impact these new Superfund provisions will have on the
types of remedies selected are potentially greater than impacts on
the RI/FS projects. The U.S. EPA has been moving away from
land disposal and approving more treatment and destruction
remedies. That direction is certainly strongly encouraged by the
new provisions and potentially will lead to the selection of more
expensive treatment remedies. Many of the rules and preferences
contained in the reauthorization language are "qualified" to
potentially allow the U.S. EPA some degree of judgment for their
application when selecting remedial actions. For example, con-
sider the requirement to select remedies that are permanent and
use alternate technology or resource recovery. It is "qualified" by
adding to the maximum extent practicable. This may give the
U.S. EPA flexibility to deal with the complicated, site-specific
problems posed by uncontrolled hazardous waste sites. However,
the U.S. EPA will have to interpret congressional intent as to how
much flexibility will be allowed. Regardless of how these decision
rules and preferences are implemented in U.S. EPA policy and
guidance, many complex technical and policy issues must be
resolved each time a remedy is selected at a Superfund site.
Improved Project Execution
It is clear that the Superfund remedial program will face in-
creased challenges to effectively implement these new provisions.
410 SITE REMEDIATION TECHNIQUES
-------
One significant impact will be the increased pressure placed on
those government and private sector managers who are responsi-
ble for conducting remedial investigations and feasibility studies
at Superfund sites. The new technical requirements will add com-
plexity and increase both time and cost of conducting projects.
Pressure will increase to find new and innovative ways to com-
plete projects within reasonable budget and time constraints in
order to attain congressionally mandated schedules. New and
largely unproven technologies will need to be applied to the wide
range of contaminants and media found at Superfund sites. Dif-
ficult decisions will have to be made with limited information on
technology reliability and performance. Much of the responsibili-
ty to meet this challenge will fall to the engineering profession.
Engineers in Federal, state and local governments and engineers
in the private sector will have to combine their efforts and utilize
the expertise of each group to be successful.
Note:
The analysis of new provisions in this paper may be modified
by final CERCLA reauthorization. This paper has not been peer
reviewed by the U.S. EPA and does not represent the policy or
position of the U.S. EPA.
SITE REMEDIATION TECHNIQUES 411
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Superfund Revisited
Grover H. Emrich, Ph.D.
SMC Martin, Inc.
Valley Forge, Pennsylvania
ABSTRACT
The implementation of remedial actions at a Superfund site is
not a guarantee against further review. In the early 1970s a chem-
ical producer was ordered by the State Regulatory Agency to re-
move sludge from a basin. The sludge was solidified and placed in
two unlined lagoons. In the middle 1970s the State Regulatory
Agency claimed that the lagoons were the source of contamina-
tion of local surface and groundwater. During the late 1970s an
exhaustive remedial investigation found additional sources of
contamination at the site. Pathways of migration were primarily
groundwater and surface water sediments. In the early 1980s a re-
medial action plan was implemented which included: removal of
sludge from the two lagoons, removal of contaminated soil from
the site and drainage ways, regrading, revegetation and stabiliza-
tion of all soils on the site and installation of a groundwater
collection and treatment system.
In the fall of 1985 the company was called to an administrative
conference by the State Regulatory Agency and U.S. EPA. The
company was informed that the previous remedial investigations
and plans did not meet all present requirements. The agencies
indicated that the company must review all the previously col-
lected data and complete a new feasibility study.
INTRODUCTION
A chemical manufacturing facility began operation in the late
1950s manufacturing specialty chemicals for private and indus-
trial use. In the course of operations, chemical compounds in
various forms were transported to and from the site. The site cov-
Figure 1
General Site Plan
ers approximately 30 acres and consists of buildings, warehouses,
storage areas and open land (Fig. 1). Since operations began,
various methods have been utilized for handling wastes at this
site. Waste handling and disposal practices conformed to
standard practices at that time.
SITE SETTING
The topography of the site slopes gently to the southwest. Sur-
face drainage on-site is diverted to a ditch which runs along the
western property line. Several springs are located in the vicinity of
the site. Of particular interest is a major spring, located approx-
imately one-half mile south of the site, which feeds a stream that
is used for trout fishing. The site is underlain by carbonate rocks
which dip to the southeast with an approximate northeast-south-
west trend. Several area thrust faults cross normal to the rock
formations. Extending from the site to the major spring to the
south is either a trace of a fault or a formation contact.
The bedrock contains abundant solution openings both above
and below the water table. These openings are responsible for
conduit systems allowing groundwater to move from the site in a
direction parallel to the surface trend of the rock layers. Ground-
water recharge is primarily through infiltration of surface waters
entering residual soils and surface solution openings near the site.
Groundwater flows from the eastern portion of the site to the
west. At the approximate location of the thrust fault, the water
table drops approximately 60 ft and flows southward to the
spring.
PAST WASTE DISPOSAL PRACTICES
Chemical production began in the late 1950s. In the early 1960s,
the company was notified of a chemical odor in the spring down-
gradient from the facility. In 1962, as part of its remedial action,
the company constructed a concrete lagoon to serve as settling
basin for wastewater generated on the site. In 1963 facilities were
constructed to contain spills at the plant. In 1965 the company
designed and began operation of the spray irrigation system on
the plant site. Chemical wastes were directed to the concrete la-
goon where the wastes were neutralized by lime addition. Waste-
water in the concrete lagoon was then sprayed on the open grassed
areas on the company's property.
REMEDIATION—1972
In 1972 the State Regulatory Agency required that the company
solidify all the sludge in the concrete lagoon. The company en-
tered into an agreement with the state and proceeded to solidify
all materials under the direction of the State Regulatory Agency.
These materials were placed in earthen impoundments (lagoons)
(Fig. 1), backfilled and graded. In addition, a separate asphalt im-
poundment was removed and all other wastes were sent off-site
412 SITE REMEDIATION TECHNIQUES
-------
for disposal. These lagoons were excavated into the underlying
soils to a depth of 8 to 10 ft. The berm was built around the la-
goons, and the solidified materials were placed in the unlined la-
goons. The company complied with all aspects of the Regulatory
Order by the end of 1972. A letter approving the remediation and
releasing the company from liability was issued by the State
Attorney General's office.
REMEDIATION—1984
In the middle of the 1970s, the State Regulatory Agency
claimed that the two lagoons were leaking and were sources of
contamination in water which was discharging into the local
stream from the spring south of the plant. The State Regulatory
Agency issued an Administrative Order in 1977 requiring the
chemical company to prepare and submit a plan for the identifi-
cation, collection and disposal of any solid wastes and soils on the
company's property which contain specific chemicals or other
substances deleterious to plant life, aquatic life, animal life and
man. Solid wastes included but were not limited to the solid-
ified material in the lagoons. Following the 1977 Administrative
Order, several sampling programs were completed on the site, in
nearby private domestic wells, in the spring and in the nearby
stream. On-site sampling included the collection of soil samples
from the surface to varying depths throughout the site, and water
and sediment samples from the freshwater ditch. In addition,
wells were drilled throughout the site (Fig. 2) to define the
groundwater flow and groundwater quality. On the basis of this
remedial investigation (RI), the sources of contamination were
defined on the site and the pathways of migration from the site
were evaluated.
SURFACE OR/
DIRECTION
PROPERTY UNE
RAILROAD TRACK
• MONITORING WELL
Figure 2
Monitoring Well Location Map
Results of the chemical analyses from the program are sub-
ject to question because standard procedures for some chem-
icals had not been developed prior to 1981. The chemical com-
pany employed an outside contractor to develop acceptable pro-
cedures for the analysis of these chemicals. Through sophisticated
methods, it was possible to detect and quantify chemical com-
pounds down to the low parts per billion level. This detection
limit was 1 to 2 orders of magnitude lower than had been possible
in the early 1970s. Improvement in analytical techniques has in-
troduced the problem of the "diminishing zero" in chemical
analyses. This problem, which continues today, means that detec-
tion limits decrease by at least one order of magnitude every 3 to
5 yr. Therefore, a site found to be clean in the early 1970s is de-
termined to be "dirty" in the 1980s because it has chemical com-
pounds present at levels in the range of parts per trillion. The
presence of chemical compounds at any level can concern the
public, trigger action by the Regulatory Agencies and subject a
company to a repeat of environmental studies completed earlier.
As a result of the chemical data obtained in the late 1970s, the
Administrative Order was amended in 1981. During 1981, the
company complied with the Administrative Order and removed
all the soils from a former drum holding area. Excavations were
backfilled with clay, regraded and vegetated. The freshwater
ditch was cleaned with a front end loader in the area of the la-
goons, and a "supersucker" vacuum truck and hand excavation
were used to clean the ditch. Contaminated materials were trans-
ported to a secure landfill. The freshwater ditch was brought back
to original grade with clean clay fill.
Materials were removed from the two lagoons in the fall of
1982. All the solidified materials plus additional soil were re-
moved from the bottom and sides of the excavated areas and
transported to a secure landfill. Closure plans for the areas of
solidified material were approved by the Regulatory Agency,
and closure was completed with a clay cap in early 1984.
Recognition that groundwater had been adversely affected and
was negatively impacting the spring resulted in the development
of a groundwater collection and treatment system. Groundwater
initially was pumped from wells adjacent to and downgradient
from the facility. These wells had the highest concentrations of
chemical contaminants. In the treatment system, water is pumped
through a countercurrent air stripper and carbon adsorption
system. Final discharge is to the surface drainage ditch on the
property. A monitoring program was implemented in 1982 which
consisted of measurements of groundwater elevation, ground-
water quality and influent to and effluent from the water treat-
ment system. Monitoring data have been compiled and monthly
reports have been submitted to the Regulatory Agency.
REMEDIAL INVESTIGATION—1986
In the fall of 1985, the company was called to an Administra-
tive Conference by the State Regulatory Agency and the U.S.
EPA. The call came as a surprise to the company because there
had been little indication of dissatisfaction with the remediation
that had resulted in the removal of surface sources of contam-
ination and the installation of a groundwater collection and treat-
ment system. Groundwater quality had improved as shown by a
general decrease in contaminant concentrations with time. The
company believed that it was conforming to all necessary permit
requirements and was effectively remediating the groundwater
pollution.
At the Administrative Conference, the company was informed
that the previous RI/FS work did not meet all the present RI/FS
requirements. (Much of the work was done previous to the pass-
ing of CERCLA and reauthorization of RCRA.) At the request
of the State Agency and the U.S. EPA, a new work plan for an
RI/FS had to be developed.
Development of the work plan required review of previously
collected data, some of which went back over a decade. Data were
reviewed from the files of the consulting engineering and geotech-
nical firm (SMC Martin), district and central offices of the State
Regulatory Agency and the regional office of the U.S. EPA. It
immediately became clear why it is necessary for a consulting firm
to retain records long after a job is completed. To quote the great
American philosopher Yogi Berra, "it ain't over 'til it's over."
Data must be reviewed in the light of present information and
technical skills. Because of this, we found it extremely valuable to
work with much of the original data and work sheets. In addition,
review of data previously accumulated by regulatory agencies in
their files was found to be time-consuming but valuable. Avail-
SITE REMEDIATION TECHNIQUES 413
-------
able internal agency memoranda helped focus on the critical
issues to be addressed in the work plan. Agency cooperation is an
important element in this review process. As a general rule, no
one file was complete; the review of all files was required to ob-
tain a complete data base.
This situation was especially true in the review of chemical
data where sampling, collection methods and analytical tech-
niques have made major advances in the last decade. We find
that the level of detection for many of the analyses is now at parts
per trillion, where a decade ago it was at parts per million. Thus,
in reviewing old chemical data, one must be aware of the detec-
tion limits.
The review of the regulatory data files also helps develop an
understanding of the changes in regulatory philosophy with time
and the confidence of the regulatory agency in its data base. This
understanding is critical for our case study because of the con-
cern about the acceptability of previous chemical results.
A work plan for a "focused" remedial investigation and feas-
ibility study has been developed. These "focused" efforts are
directed toward site specific control features and data gaps partic-
ularly directed at the groundwater flow regime. The feasibility
study also will be focused toward defining the effectiveness of
the present remedial activities in meeting the State Regulatory
Agency orders. If necessary to meet agency goals, supplemental
remediation will be identified, evaluated, selected, designed and
implemented at the site. All these Rl/FS activities will be com-
pleted in a manner consistent with today's requirements and SMC
Martin's perception of what may be reasonably expected in the
future. Only the future will tell whether this site will be "revisited
again."
CONCLUSIONS
Long-term efforts by a chemical producer to define and remed-
iate contamination at a site have met with the State Regulatory
Agency approval. However, this approval is no assurance that
present or future state and federal agency regulations will not re-
quire further investigations and remediation at a site. As analyti-
cal techniques have become more sophisticated, it has become
possible to detect compounds in ever smaller quantities at any and
all sites. This increasing sophistication in analysis leads to the
"diminishing zero" problem where the next generation of ana-
lytical techniques changes "not detected" levels into "quanti-
fiable" levels, and materials which were absent suddenly appear
on sites.
Because "focused" studies (revisits to a site) may be required
in the future, it is important that all data, records and reports
be carefully and completely maintained by the company, its con-
sultants and other parties. These data must be maintained in such
a format that they can be evaluated by persons not involved in the
original studies and in the light of advances in scientific knowl-
edge. They also must be maintained with the realization that it
may be necessary to provide data to regulatory agencies.
414 SITE REMEDIATION TECHNIQUES
-------
Investigation and Remediation of
A Pond Contaminated by Diesel Fuel
Lon M. Cooper, P.E.
Richard K. Hosfeld, C.P.G.
Soil & Material Engineers, Inc.
Fair field, Ohio
ABSTRACT
Several diesel fuel spills occurred at a truckstop in Ohio, and
significant amounts of fuel drained into a pond located 900 ft
downstream. The pond became anaerobic and could not support
aquatic life. On two occasions, the landowner burned large ac-
cumulations of fuel from the surface of the pond. In addition,
areas of biologic stress were evident along the drainage path to
the pond. In an agreement with the State of Ohio, an environ-
mental investigation was initiated to evaluate the magnitude and
extent of the contamination.
The investigation included hand-augered soil borings, chemical
analyses of soil and sediment samples collected from the area
downstream of the truckstop and a biological assessment. Based
on the results of these studies and the preferences of both the
client and the landowner, the contaminated soil was excavated
and the pond was closed. A total of 7500 yd3 of fuel-contami-
nated soil was removed from the site to an approved landfill.
During the excavation, the pond became filled with uncontam-
inated sediment from the pond bottom. This sediment could best
be characterized as an organic muck having a water content as
high as 88% by weight. The pond was closed using geotextile fab-
ric to stabilize and solidify this muck. This action saved approxi-
mately $300,000 in comparison to the projected costs for total ex-
cavation and backfill.
INTRODUCTION
This paper presents the results of an environmental investiga-
tion and the remedial actions taken at a full service truckstop lo-
cated in Ohio. Over the years, several diesel fuel spills occurred
resulting in significant amounts of fuel draining into a pond lo-
cated 900 ft downstream of the truckstop (Fig. 1). On two occa-
sions, the accumulation of diesel fuel was burned off the pond.
The flow path of the spills from the truckstop to the pond was
marked by areas of biologic stress, and the pond became incap-
able of supporting fish and other aquatic species of life normally
present in similar ponds.
In an agreement with the State of Ohio, the management of the
truckstop initiated an investigation to assess the physical con-
dition of the site, to assess the environmental impact of the diesel
fuel spills and to develop any necessary remedial actions. The in-
vestigation included an assessment of the soils and surface water
in the impacted area, as well as a biological assessment.
SITE DESCRIPTION
Topography in the area ranges from flat to gently rolling ter-
rain. Surface drainage flows toward the west into the Mill Creek
drainage-system. A large area south and west of the truckstop had
been strip mined for coal and was covered by deposits of strip
mine spoil. The pond was constructed in this strip spoil, approx-
imately 900 ft west of the truckstop. Surface water from the
truckstop drains into this pond.
Immediately downslope from the truckstop is a wide meadow
surrounded by scrub forest. The forest closes in around a defined
stream about halfway to the pond. Between this point and the
truckstop, the drainage was poorly defined, migrating laterally
across the meadow. The diesel spills covered an area from approx-
imately 50 to 70 ft wide as runoff drained toward the pond. In this
area, significant stress to the vegetation was observed throughout
the meadow; barren areas were covered by black mucky soils,
yellowing shrubs and dead trees. Further downstream, the chan-
nel became well-defined and areas of biological stress were con-
fined to the immediate vicinity of the channel.
The pond was constructed by the landowner for recreational
purposes. It was reported that the pond was originally about 20
ft deep. At the time of the investigation^ the pond measured ap-
proximately 120 ft by 310 ft, and averaged 8 to 10 ft deep. Dis-
charge from the pond flows toward the west through about 200
ft of established woods before reaching a cultivated area where
the stream eventually enters a tributary to Mill Creek.
ENVIRONMENTAL SAMPLING PROGRAM
A two-phase sampling program was initiated on Oct. 2, 1984,
to obtain soil and pond sediment samples for chemical analysis.
The objective of the sampling program was to assess the degree of
1'-250'
Figure 1
Site Map of Study/Cleanup Area
CASE HISTORIES 415
-------
diesel fuel contamination and its area! extent downstream of the
truckstop. A total of 127 soil samples was collected from 63 sta-
tions located downstream of the truckstop and analyzed for diesel
fuel content (Fig. 2).
TruokBtop 1
• iimpl.i ooll.cKd 4/10/tt
• nd 6M/6I
Figure 2
Site Map Showing Sampling Locations
1" = 100'
During Phase I of the investigation, a total of 45 samples was
collected from 30 sampling stations located along the drainage
path between the truckstop and the pond. At each station, soil
samples were collected at approximately 1-ft vertical intervals.
The sample and depths are listed in Table 1.
Table 1
Diesel Fuel Analysis of Soil & Sediment Samples
Truckstop Environmental Sampling Study, Phase I Sampling
STATIC
ID
A'
B
C
C
C
D
D
0
El
El
E2
E2
PI
PI
PI
P2
P2
P2
C
C
C
H-
•
.
N*
0
o
0
p
p
0
0
R
R
S
s
T
T
0
U
V
W
X
1
Zl
12
Z3
*
LOCATION
0.00
1.00
1.20
1.20
1.20
l.ao
i.eo
1.10
2.00
2.00
2.00
2.00
3.00
1.00
3.00
I. 00
3.00
3.00
3.75
3.75
3.75
4.00
5.00
S.70
6.00
7.00
7.00
7.50
7.50
1.00
6.15
1.15
6.15
9.00
9.00
Pond Edge 11
Pond Edge 11
Pond Edge 15
ond Edge 15
ond Edge 1 2
ond Edge 12
ond Edge 1 3
ond Edge 13
'ond Edge 14
ond Edge 14
Pond Trib.
Discharge 1.00
Discharge 1.60A
Diicharge 1.60B
Pond Sed S
Pond Sed C
Pond Sed N
SAMPLE
DEPTH
0-f
12-17'
16-27"
o-f
12-17-
24-30-
0-f
12-16-
0-4-
12-16'
0-4'
12-14'
24-24'
0-4-
12-li-
20-24-
0-4-
12-16-
24-26-
0-4-
0-f
12-16-
0-C
12-16*
o-»-
12-16-
24-30'
0-i-
12-16-
0-f
12-16-
0-f
«-14-
0-3-
10-13-
0-f
10-15-
0-4-
9-H-
0-6-
0-6-
0-6-
Bottoa t »'
Botto. « 7.3'
Bottom ( S'
DIESEL PUEL
COHC M/kg
4, tOO
14,500
1,790
1,760
100
•100
4,760
7,660
tot
4,720
6,020
(40
•100
•100
•100
•100
40,300
1,630
•100
ISO
240
•100
•100
1*0
1,520
•100
1,0»0
•100
3, 3tO
•100
•100
•100
•100
•100
4,430
•100
SSO
•100
2, ISO
3.270
•100
•100
• 100
•100
P1ELO
PH
7.t
7.7
B.O
• . U
7.6
7.5
1.0
7.7
t.l
7.1
t.t
7.4
7 5
7 4
7 3
7 5
7 <
7 1
COND.
uahoi
1.100
1.100
1,050
1,050
1,000
1,000
1,050
1.200
2,150
2.500
3,200
1,200
2,400
2,200
2,200
1,200
1,200
1,700
Soil samples were collected from two depths at each of five
stations (Q through U) along the edge of the pond. These are
shown on Fig. 2. Additional soil samples were collected along the
discharge stream from the pond (Stations W, X and Y).
Three bottom samples of pond sediment were collected for
analysis. These samples were obtained using an inflatable raft and
a scoop to dredge sediment from the pond bottom. The loca-
tions of these samples are shown on Fig. 1 as Zl, Z2 and Z3. The
depths ranged from 5 to 8 ft as shown in Table 1.
During Phase II, an additional 82 soil samples were collected to
further define the extent of contamination. The samples were col-
lected from 35 stations located along the drainage course between
the truckstop and an area downstream of the pond. Twenty-
three sampling stations were established along the drainage path
and are shown as stations AA through FE in Fig. 2. Three addi-
tional stations were established around the edge of the pond and
are labeled as stations PA through PC in Fig. 2. Ten more sta-
tions were established downstream of the pond's discharge point.
Only two of these stations (GA and GB) are shown on the map in
Fig. 1, the others (GC-GJ) are located off the map. The sample
stations, locations, depths and analytical results are presented in
Table 2.
Table!
Diesel Fuel Analysis or Soil & Sediment Samples
Traclutop Environment*! Sampling Study, Phase II Sampling
STATION SAMPLE DIESEL PUEL FIELD COM).
10
AA
AA
AB
AB
AC
BA
BB
B8
BC
BC
BD
BD
CA
CB
CC
CD
CD
CE
DA
DB
DB
EA
EB
EC
ED
ED
PA
PB
PC
PO
PE
PA
PA
PB
PB
PC
PC
CA
CB
•CC
•CO
•CE
•CP
•CC
•CK
•CI
•CJ
UXAT10B DEPTH COMC «g/kq OH late!
1.00, 40' n
1.00, 20' N
1.00, 20' S
2*00, 40' N
2.00, 20' N
2.00. 20' S
1
2.00, 40' S
2.00, 40' S
1.00. 60'
3.00, 50'
3.00, 30'
3.00. 20'
3.00, 40'
3.70, 40'
3.70, 20'
4.50, 60'
4. SO, SO'
••SO, 30'
4. SO, 30'
5.50. 60'
5.50, SO'
.
-
t-
_
_
_
-
-
-
1
_
_
>-
_
_
-
-
-
-
-
-
.
-
_
0-
1-
0-
0-
S.SO, 30' M 0-
5.50, 30* S 0-
1-
5. SO. SO' S 0-
Pond Sid* 0-
1-
Pond Sid* 0-
l-
Pond Marah 0-
1-
Pond l.SO'. Straaai 0-
Pond l.SO, 10' S 0-
Pond 2.00, 40' N 0-
1-
Pond 2.00, 20' M 0-
1-
Pond 2.00, 20' S 0-
1-
Pond 2.00, 40' S 0-
1-
Road 2.00, 40' N 0-
1-
Road 2.00, 20' M 0-1
1-2
Road 2.00, 20' S 0-1
1-2
Road 2.00, 40' S 0-1
20
10
20
• 10
4600
•10
30
•10
240
S' -10
•10
•10
•10
40
640
to
to
(0
•10
1170
170
•10
•10
•10
SO
to
•10
20
•10
4(0
90
170
• 10
•10
•10
•10
•10
•10
•10
•10
•10
•10
•10
•10
•10
•10
•10
•10
•10
•10
•10
•10
•10
•10
•10
1-2 >10
*Noi shown on map,
*Not shown on map.
BIOLOGICAL ASSESSMENT
The objective of the biologic site inspection was to determine
the effect of discharged diesel fuel on the biota of the areas. As
previously described, diesel fuel spills from the truckstop followed
416 CASE HISTORIES
-------
a natural drainage path to the small man-made pond (Fig. 1).
The diesel fuel concentrations found in the soil samples col-
lected during the environmental sampling program were signifi-
cantly high and can be expected to adversely impact vegetation,
benthic organisms and pond fauna. The effect of diesel fuel on
vegetation is usually first expressed in the yellowing of leafy ma-
terial; eventually the entire plant dies. Yellowing and death of
larger trees generally indicates a deep penetration of the contam-
ination.
Drainage Ditch
Significant stress to the vegetation was observed in the area be-
tween the truckstop and the pond. The area directly downslope
from the truckstop was void of healthy vegetation, and much of
the area was covered with a black, mucky soil. In some places,
free oil was found on the surface. A winding area of similar char-
acter continued through the meadow vegetation to three similarly
void areas farther down the drainage path. These areas were
measured and found to be approximately 600, 200 and 140 ft2 re-
spectively. Within or alongside these areas, more than 20 trees
were dead. Each had a diameter at breast height (DBH) of 1 to 3
in.
Benthic Organisms
The stream course was searched for benthic organisms on two
different occasions, but none were found. Rock samples were
taken back to the laboratory, picked and examined microscop-
ically. No benthic organisms were found. Glucose solution was
used to float out any organisms, but again, to no avail. The tox-
icity of diesel fuel components to benthic populations appears to
be responsible for the lack of benthic organisms along the drain-
age path to the pond.
Pond
Dissolved oxygen levels were measured at four locations around
the pond. The average level for each location was as follows:
Sampling Site
Dissolved Oxygen (Concentration mg/1)
a) Stream leaving pond
b) West side of pond
c) South side of pond
d) East side of pond
3.1
1.6
1.8
1.3
The measurements were taken at 6:30 p.m. on Oct. 2, 1984; all
oxygen concentrations were well below the levels required to sus-
tain most higher forms of aquatic life.
Samples of the pond sediment were taken to the laboratory and
examined microscopically. No insects or insect exuviae were dis-
covered. One damselfly shell was found alongside the pond, and a
bullfrog tadpole (Rana catesbiana) was collected from the water.
No signs of life were observed. Samples of the pond water under-
neath the oil layer were examined microscopically. The green
algae Spyrogyra sp. was found mixed with tiny droplets of oil
emulsified in the water.
RESULTS
Results of the environmental sampling program and laboratory
analyses indicate that diesel fuel was present in the soils of the
study area at concentrations of up to 40,300 mg/kg (Table 1). The
extent of contamination as a result of the diesel spills at the facil-
ity was not limited to the drainage area just below the facility, but
extended to the pond and beyond it (Fig. 3).
Figure 3
Site Map Showing Diesel Fuel Contamination Levels
1" = 100'
Eighteen of 123 soil samples had diesel fuel concentrations in
excess of 1,000 mg/kg. Most of the higher concentrations were
found in samples along the drainage path between the truckstop
and the pond. Only three of the surface samples (0 to 6 in. deep)
taken from the edge of the pond had detectable levels of diesel
fuel. However, none of the samples from the bottom of the pond
contained detectable levels of diesel fuel. Relatively high concen-
trations of diesel fuel were detected along the discharge stream
from the pond.
Diesel fuel was detected in 36 of the soil samples along the
drainage path. Of these samples, 7 had concentrations in excess of
1,000 mg/kg. Most of these higher values were located in areas
where the drainage was poorly defined, and the fuel had accumu-
lated in depressions away from the primary drainage channel. At
the stations where deeper samples were collected, most of the
samples showed a decrease in diesel concentration with depth,
except at stations C, E and O. These areas showed an increase in
the concentrations with depth. Results of the sampling and chem-
ical analyses indicate that the diesel contamination was limited to
a depth of less than 2 ft.
Based on the soil sampling around the pond, we concluded that
the contamination was concentrated in the shallow surficial de-
posits of muck and partially decayed plant matter. Little diesel
fuel was detected in the clayey soils beneath the muck. Samples of
the sediment from the bottom of the pond at locations Zl, Z2 and
Z3 did not contain detectable levels of diesel fuel. In the area of
the pond and associated marsh, persistent contamination ap-
peared to have occurred only in the shallow surficial muck depos-
its around the edge of the pond and the swamps.
The analyses of the two soil samples collected downstream of
the pond in Phase I indicate that significant contamination of
soil extends beyond the pond. Concentrations of over 2,000 mg/
kg of diesel fuel were detected in the soil. Phase II showed that
this contamination did not extend 200 ft downstream from the
pond.
Significant biological distress was noted in the study area as a
result of the diesel spills. In large areas, the establishment of veg-
etative ground cover was retarded. Some areas contained estab-
lished trees and shrubs which died as a result of diesel contamina-
tion. A biological survey of the stream indicated an almost total
absence of aquatic life in this area.
Dissolved oxygen levels in the pond are below the levels re-
quired to sustain most common aquatic life. No aquatic organ-
isms were found in the pond except for a few tadpoles. The pond
had euxinic bottom conditions where the water was so stagnant
CASE HISTORIES 417
-------
that organic matter reaching the bottom of the pond was shielded
from oxygen and decay.
REMEDIAL ACTION
Several remedial action alternatives for dealing with the diesel
fuel contamination at the site were considered and assessed. The
alternatives were: (1) no action, (2) total removal, (3) in situ treat-
ment and (4) land farming. Based on the potential effectiveness of
each option and the estimated cost of each method, land farm-
ing was recommended as the most suitable remedial action. How-
ever, the preferences of both the client and the landowner led to
the total excavation and removal of the contaminated soil and,
subsequently, the closure of the pond.
Originally, excavation of the contaminated soil ( >100 mg/kg)
was to have been accomplished in three phases. During the first
phase, the pond was to have been drained to allow the contam-
inated soil along the edge of the pond to dewater. This step would
have allowed the moisture content of the contaminated sediment
to decrease to a level where soil solidification would not have been
necessary. In the second phase, the contaminated soil in the drain-
age ditch was to have been excavated to an approximate depth
of 2 ft and regraded. During the third phase, the pond was to have
been completely drained and the contaminated soil excavated.
The proposed excavation boundaries are shown in Fig. 4.
This process did not occur as planned because of conditions
imposed by the geology of the site, the Ohio EPA (OEPA) and
the landowner. The latter requested that the pond be filled in,
which resulted in the fourth phase, pond closure.
Draining the Pond
Initially, an attempt was made to drain the pond by lowering
the elevation of the outlet. When the outlet was excavated, flow
from the pond was so great that it disturbed the organic sediment
on the bottom of the pond, and some of this material moved
downstream. Although the organic sediment previously had been
found to contain < 100 mg/kg diesel fuel and was considered
harmless, the landowner and the OEPA wanted the flow stopped.
As a result, a second attempt to drain the pond began. Two
high capacity pumps were used. The intake hoses were suspended
from a floating barrel to prevent the sediment and organic muck
in the bottom of the pond from being drawn into the pumps and
subsequently discharged. Personnel were stationed by the outlets
to monitor discharge and ensure that no organic sediments were
being discharged to the stream. When sediments were detected,
the locations of the inlet hoses were adjusted until the levels were
such that the pumps had to be cut off. In addition, water flowing
into the pond was rerouted to limit the recharge to the pond.
Once the pond was drained as much as possible, the elevation of
the outlet was lowered to prevent the water from rising to its orig-
inal elevation.
Truekitop>-
•nd f/4/fS
Propouo" tlmlu el cleanup
Figure 4
Site Map Showing the Proposed Limits of Cleanup
1" = 100'
U«lu »t Prepeee« Cleanap
Aelatl UBJle «f Cleanup
Figure 5
Site Map, Boundaries of Cleanup
1" = 100'
Excavation of the Drainage Area
In the second phase, contaminated soil in the drainage ditch
was excavated and hauled to a landfill. Along the drainage path,
soils were excavated to an average depth of 3 ft and decreasing to
a depth of 1 ft as the excavation boundaries were reached. A map
showing the actual area! extent of excavation is shown in Fig. 5.
At several points along the stream channel, excavation went much
deeper due to the excessive levels of contamination found. Ap-
proximately 1800 yd3 of fuel-contaminated soil were excavated
from the drainage course and hauled to the landfill. Upon com-
pletion of the excavation, the area was regraded, fertilized and
seeded.
Excavation Around the Pond
Excavation of the contaminated soil around the pond did not
proceed as originally planned. The landowner requested that the
pond be filled in and that the trees located around the pond be
allowed to remain standing. As a result, the excavation had to be
accomplished from inside the pond area where soil conditions
would not support the weight of the construction equipment.
To accommodate this process, an earthen ramp and work pad
were built at the southern end of the pond. From the work pad, a
back hoe was used to excavate the contaminated soil, which then
was replaced with fresh soil brought in from a local construction
site. The soil was used to extend the work pad area and to con-
struct a haul road for the trucks moving in and out of the site
along the edge of the pond. As the fresh dirt was hauled in and
dumped along the edge of the pond, sediment at the bottom of
the pond was displaced toward the center. When the mouth of the
outlet stream was reached, the pond was effectively divided in two
by building a coffer dam/road from west to east across the pond,
and the accidental discharge of sediments into the outlet stream
was prevented.
Excavation then continued until the contaminated soil around
the pond was removed. During construction of the access road,
the original area of the pond was reduced by approximately 40%,
free water was discharged to an adjacent stream and the organic
sediment in the bottom of the pond was retained and collected
in the center of the pond. Approximately 5700 yd3 of fuel-con-
taminated soil were excavated from around the pond and taken to
a landfill for disposal.
Pond Closure
As a result of the procedures used to excavate the contaminated
soil, two ponds containing displaced sediment from the bottom of
the pond were created. The north pond measured 100 by 100 ft
with an average depth of approximately 15 ft, while the south
pond measured 83 by 180 ft with an average depth of approxi-
mately 25 ft. Each pond was filled with a sediment best described
as muck. The material was not contaminated, had a high flash-
418
CASE HISTORIES
-------
point (180°F) and was saturated, containing as much as 88%
water by weight. Because of its high water content, the muck
could not be removed to a landfill or buried in situ without treat-
ment.
Treatment of the muck would have required solidification us-
ing kiln dust, fly ash or other cementaceous materials. Based on
the available data, the estimated cost of solidifying the muck
would have been in excess of $250,000. During this process, the
volume of the muck would have increased a minimum of 100%,
necessitating removal of some of this material to a landfill at an
estimated cost of $200,000. The area then would have to be re-
graded and capped with clean soil. It is estimated that the total
cost of this project would have exceeded $550,000. By using geo-
textile fabrics to stabilize and solidify the muck, the cost of clos-
ing the pond was $198,000, a savings of over $300,000 over the
removal cost.
The basic concept of mechanical stabilization is to use the nat-
ural weight of a cover soil to consolidate and dewater the sedi-
ment. A layer of geotextile fabric is placed on top of the sediment
to provide support, a thin layer of sand is spread across the fabric
to provide a drainage layer and then cover soil is spread on top
(Fig. 6).
060TEXTILE FABRIC
SAND
COVER SOIL
18' pond -
Figure 6
Detail Section of Pond and Anchor Trench
SAND
EXPOSED FABRIC
' FABRIC WITH COVER SOIL '
Figure 7
Stages of Geotextile Fabric Installation
Prior to the installation of the fabric, the site had to be proper-
ly prepared. The muck in the north pond was transferred to the
south pond (Fig. 5). During the excavation of the contaminated
soil, streams coming into the pond were diverted. A ditch to carry
these streams across the area was designed specifically to act as a
catchment basin for the initial discharge of water coming from the
south pond during stabilization. This ditch was constructed in the
area of the north pond. If an emergency had occurred, the ditch
could have been used to contain any organic sediment as it left the
site.
Next, the road around the site was cut to the same elevation as
the muck and graded to match the surrounding topography.
Finally, two trenches were constructed on the south and west ends
of the site to anchor the fabric (Fig. 6). These sides were chosen to
prevent a sediment spill from discharging to the stream below the
pond.
The fabric selected for the project was manufactured by Car-
thage Mills and measured 150 by 260 ft. The fabric had a burst
strength of 585 lb/in.2. The fabric was stretched over the pond
and the edges were buried in the anchor trenches.
Once the fabric was in place, soil was end-dumped along the
west, south and east edges of the fabric (Fig. 7A) and spread to an
approximate depth of 3 ft using a small, wide-track dozer with 2.6
lb/in.2 contact pressure. On the northern end of the pond, 1 ft of
sand was positioned on top of the fabric, and then 2 ft of soil
were emplaced on top of that. This process kept the fabric from
slipping and provided a drainage pathway for water being ex-
truded from the muck.
A layer of sand then was placed over the rest of the fabric to
provide a drainage path for the water being pressed out of the
sediment (Fig. 7b). The sand was placed in 5-ft strips starting
along the northeast side of the pond and working around the edge
of the haul road until the entire pond was covered. This process
prevented any sediment spillage due to uneven loading and pro-
vided a solid working surface for the final soil placement and
grading.
Originally the sand layer was designed to be 2-ft thick; how-
ever, because of the inexperience of the operator with this type of
operation and the large amounts of water being released from the
sediment, the sand often reached thicknesses of 4 ft. Finally, a
2-ft layer of dirt was placed over the top of the sand to add weight
and cap the pond (Fig. 7c).
CONCLUSIONS
During the course of the project 7500 yd3 of fuel-contaminated
soil were excavated from the site and removed to an approved
landfill. Over 12,000 yd3 of clean fill were used at the site to re-
place the contaminated soil and construct the haul roads. By us-
ing geotextile fabrics to stabilize and solidify the organic sedi-
ment, a cost savings of approximately $300,000 was realized for
closure of the pond.
CASE HISTORIES 419
-------
Innovative and Cost-Saving Approaches to
Remedial Investigation and Cleanup of a
Complex PCB-Contaminated Site
Kevin Chisholm, P.E.
Charles E. Newton, Ph.D.
Anthony F. Moscati, Jr., D. Env.
WAPORA, Inc.
Rosslyn, Virginia
ABSTRACT
A combined remedial investigation and feasibility study was
performed on a complex PCB-contaminated passenger railroad
terminal. A statistically based iterative sampling and analysis
scheme and several mathematical models developed for migration
of PCBs in various media together will save from 30 to 60% of the
time and cost that would otherwise be required for the investiga-
tion and cleanup. Several processes were examined for waste
minimization through physical/chemical separation of approx-
imately 1,000 tons of PCB-contaminated waste from 3,000 tons
of insignificantly PCB-contaminated waste.
Evaluations of PCB contamination were made for over 15
types of substrates, including soil, rock, wood, asphalt, concrete,
steel, glass and roofing paper, among others. A screening tech-
nique, thin-layer chromatography, was tested for use in providing
quick determinations of highly PCB-contaminated samples, but
was adversely affected by masking organic compounds. As
cleanup proceeds, an on-site mobile laboratory will provide
critical quick sample turnaround.
INTRODUCTION
In the spring of 1985, the owner of this complex passenger
railroad terminal initiated a remedial investigation of PCB con-
tamination. The majority of the on-site PCB contamination
resulted from the use over several decades of electric-powered
railroad cars with PCB-containing transformers. The PCB con-
tamination generally was viewed as historic because it primarily
occurred prior to the implementation of the Toxic Substances
Control Act of 1979. Therefore, the law allowed time to assess the
best approach to clean up the site.
The terminal consists of an elevated, 1,100-ft long viaduct
which provided access by trains, a 150,000-ft2 (about 4 acres) ter-
minal shed which provided cover to passengers and an interstitial
space which separates the floor of the shed from a public facility
below.
The site posed many technical and logistical problems because
of its size, uniqueness and urban location. WAPORA was
selected to perform a remedial investigation and ultimately
oversee cleanup of the entire site. From the outset, an iterative ap-
proach to the remedial investigation was utilized in order to
minimize costly and unnecessary investigative efforts. For exam-
ple, the trackbed sediments in the terminal shed were quickly
tagged for cleanup, since a limited number of samples all showed
substantial PCB concentrations and it was known that PCBs had
a strong affinity for the sediments. On the matter of air con-
tamination, early results showed non-detectable PCB concentra-
tions. As with the trackbed sediments, a knowledge of the
chemical nature of PCBs was used in combination with early
sampling results to minimize the need for a more intensive in-
vestigation. Air sampling was continued, but less comprehensive-
ly.
The following sections detail the innovative and cost-saving ap-
proaches taken during the remedial investigation and in the
development of the cleanup plan for the viaduct, the terminal shed
and the interstitial space.
VIADUCT
The viaduct provided an elevated structure for access to the ter-
minal by passenger trains. The upper 3 to 4 ft of the viaduct
generally consist of railroad ballast (granite rock), which varies
from 1 to 3 in. in diameter, interspersed by sand, cinders and ash-
like fine materials. The structure beneath the ballast and fines con-
sists mostly of landfilled demolition materials. There is a concrete
base underlying the ballast and fines over about one-third of the
viaduct, which serves as an elevated support for rail overpasses.
Remedial Investigation
To perform the remedial investigation efficiently and to generate
results which would be most useful in the development of the
cleanup plan (i.e., serve as a feasibility study), several key objec-
tives were identified at the outset:
• Determine if a statistically significant correlation exists be-
tween depth and PCB contamination
• Determine the extent and depth of PCB contamination
• Determine if a statistically significant correlation exists be-
tween sediment and ballast PCB contamination
Randomly selected samples of viaduct sediment were taken on a
grid system at 50-ft intervals on the north/south axis and at 25-ft in-
tervals on the east/west axis. Most samples were taken at 6- and
12-in. depths since the shallow layer was already considered con-
taminated. A statistically significant correlation was found for de-
creasing PCB concentrations in the sediment with increasing depth:
d = 0.5 log Co
(D
Cd
where:
Co = sediment concentration of upper layer
Cd = PCB sediment concentration at a depth d below the
upper layer
d = depth in ft
Simply put, the PCB concentration was found to decrease by
approximately one order of magnitude for each 6-in. increase in
depth. This correlation was consistent and reliable enough to be
applied to remedial investigation results and eliminate the need
420 CASE HISTORIES
-------
for perhaps another 100% of the sample collection and analysis
effort already performed. Identifying this correlation provided
the groundwork to more easily determine the depth of ballast/
sediment removal needed. The viaduct was split into 16 areas,
each having similar levels of PCB contamination. The correlation
was used to create statistics for each area, thus providing a sound
basis for a "semi-surgical" approach for removal.
The last major objective of the remedial investigation of the
viaduct was to determine the correlation of PCB contamination in
sediment versus adjacent ballast. Since sediment has a greater
surface-area-to-volume ratio than ballast and the ballast is im-
penetrable to PCBs, the theory was that sediment-free ballast
samples would have substantially lower PCB contamination levels
than sediment samples from locations directly adjacent to them.
The results showed that, in fact, the ballast PCB concentrations
were significantly lower than those of the sediment. However, a
fairly significant range of from 10 to over 100 existed for the ratio
of the sediment PCB concentrations to the ballast PCB concen-
trations.
Feasibility Study
Analytical tests performed on the ballast showed that the PCB
contamination was a surface phenomenon and that the ballast is
impenetrable to PCBs (Table 1). In fact, the results showed that,
for selected samples, the PCBs were readily extracted from the
ist in a solution of hexane within IS to 60 min.
Table 1
Results of Ballast Rock Analysis for PCBs
hpch
Uutln1 (ft)
UO 1, 0.01
HO 1, 0.03
HO I, 0.03
HO K, 0.03
HO 1, 1.00
100 1, O.OLV
M I, 0.03
tOO I, 10 0.03
Co t 1
I*..?..* .UMvad ttttr
l.D. t is Bit..*
Ill —
3104 —
IOH —
311 —
511 —
HK s.a
303 0.73
3090 O.U
tU.BT.td »lttr .U«i*ci) ifc.tr
(0 «lo.fc It hri.fc
— I.I
— 1.8
— 3J.O
— 1.00
— 0.33
0.23 —
(0.1 —
<0.1
• •ttiMflt
UMlolnse (pp>)
<0. 47
<0. 210
<0 9300
<0 73
<0 M
<0 290
<0 43
<0 20
eoBtiBlnitlaa
IB toll v*nu»
tMllMt
3,
117
173
71
109
72
37
44
a. Distances in ft; N = north of shed mouth; E/W = distance east or west of centerline of track
1 in terminal shed.
b. Extraction of sample rock in hexane solvent.
c. Remaining ballast rocks were crushed and total extraction of remainder was analyzed.
d. PCB concentration in soil adjacent to ballast.
The results of the remedial investigation showed a wide range
of ratios of sediment PCB concentration to ballast PCB concen-
tration. This range was primarily the result of one major problem:
clumps of oily sediment with strong cohesive properties were fre-
quently fused with the ballast rock or formed wholly separate
clumps which were difficult to distinguish or separate from the
ballast. Therefore, several options were evaluated for converting
the ballast to a non-regulated material which would not require
disposal as a PCB-contaminated waste. These options included:
• Simple physical separation through screening
• Physical separation through vigorous vibration and screening
• Physical separation through tumbling enhanced by the addi-
tion of agitating attachments
• Enhanced physical separation followed by a detergent wash
• Enhanced physical separation followed by a solvent wash
The options involving chemical actions (washing) required au-
thorization from the U.S. EPA to use PCB-contaminated
materials in testing such techniques. Tests of simple screening
separation of ballast and sediment, which required no authoriza-
tion, showed that approximately 35% by weight of the finer
material can be removed easily by simple screening and disposed
of as a PCB-contaminated waste (Fig. 1). The remaining 65%
contained less than 35% of the total original PCB contamination.
Enhanced screening alternatives include the use of vibratory
grizzly screens (similar to foundry shake-out units) followed by
shot blasting with recycling of shot. These are pre-developed tech-
nologies used by the foundry industry to separate molding sands
from newly formed casts. Other physical separation alternatives
include: (1) the use of a rotating, inclined cylindrical screen (trom-
mel) enhanced by the addition of reusable agitating attachments
in a flow-through operation, and (2) a batch operation using a
cement-mixer type of device to agitate the ballast in unison with
reusable agitating attachments.
Figure 1
Simple Screening Separation Technique
The detergent washing technique could only be followed by one
of the previously discussed physical separation steps. The
detergent washing can be performed on a batch or flow-through
basis. It involves reclamation of the wastewater through diato-
maceous earth filters and granular activated carbon columns.
It presently is anticipated that an on-site mobile laboratory will
be used to provide quick turnaround analysis of PCB samples.
This will be critical since materials which are assumed to be clean
after separation will be stored until quality assurance samples
demonstrate that fact.
TERMINAL SHED
The terminal shed is a structure nearly 4 acres in area with an
arched, structural-steel-supported spanning roof. It is open at one
end to allow trains to enter. The floor consists of alternating rows
of dual trackbeds and elevated passenger walkways constructed
of concrete and asphalt (Fig. 2).
CASE HISTORIES 421
-------
Figure 2
Cross-Section of Trackbed and Passenger Walkways in Terminal Shed
Remedial Investigation
Three types of samples were taken and analyzed in an effort to
delineate the extent of contamination of materials and surfaces
within the shed and link areas of the terminal. First, wipe samples
of vertical surfaces (including structural steel, glass and metal
duct work) and floor surface were taken to identify the extent of
surface contamination. Second, passenger walkway materials
(mostly asphalt with some concrete) were sampled and analyzed
to determine the extent of permeation of PCB materials into these
surfaces. Third, the vertical and horizontal penetration of PCBs
into wooden support structures within the trackbed was deter-
mined by taking samples of the 2-in. thick bed support planking
between track rail supports and the 14-in. wide by 10-in. high rail
support beams.
Scientists from the U.S. EPA were concerned before the
remedial investigation that re-entrainment of PCB-contaminated
particles may have occurred throughout the entire shed structure.
Therefore, the objective of the remedial investigation was to
determine the level of PCB contamination relative to the U.S.
EPA high-contact surface PCB contamination action level of 10
/tg/100 cm2. A secondary objective of the remedial investigation
was to test the hypothesis that the PCB contamination that was
present would decrease rapidly as height above and distance from
the trackbeds increased.
Thirty-four wipe samples were taken and analyzed. All results
showed surface contamination levels to be less than the 10 /tg/100
U.S. EPA action level, with most below 1 fig/100 cm*. The
• 00* ttf
no lor IK- tor no1
Figure 3
Terminal Shed Walkway Surface Material Sample Locations
results also generally supported the hypothesis that PCB con-
tamination decreased with height above the trackbeds.
The wearing course in the passenger walkways consists of
asphalt and, occasionally, concrete (Fig. 2). A combination of
wipe samples and substrate samples was used to evaluate the ex-
tent of PCB contamination in the walkways. In all, 10 substrate
samples were taken in the walkways (Fig. 3). Several substrate
samples were taken in pairs at the surface and at depth in order to
evaluate the potential for downward PCB migration. The
substrate sample results all supported the conclusion that PCB
contamination, theoretically from tracking, was insignificant in
the materials.
The trackbeds consist of 2-in. thick planking overlain by a
heavy woven fabric and by deposits of dust and soil. The rails are
supported by hardwood pads above hardwood rail support beams
(Fig. 2). The trackbed deposits and heavy woven fabric were
determined to be PCB-contaminated during a prior, less detailed
study. The underlying 2-in. support planking, however, was
found, surprisingly, to be insignificantly PCB-contaminated
through several randomly selected (and worst-case selected)
sampling efforts.
The hardwood pads, due to their small size and proximity to
potential PCB sources, also were assumed to be PCB-
contaminated.
The hardwood rail support beams posed the most challenging
portion of the shed investigation. The beams' dimensions are 10
in. high by 14 in. wide by 50 ft long. In all, there are over 2 miles
of total beam length. The size and total available length of the
beams make the potential resale of non-contaminated portions
quite attractive. An evaluation of their potential resale is under
way. The hypothesis was made that PCB penetration into the
beams was primarily from the top and secondarily from the sides,
and decreases with increasing depth. Fifteen composite samples
of wood at various depth intervals from the top and sides of
several beams (including suspected worst-case beams) were taken.
The following correlation of surface PCB contamination and
concentrations at depth was determined:
Cs/Cd = (6.0 X Dp) - 0.5 (2)
where:
Cs = PCB concentration at the upper (or starting) depth
Cd = PCB concentration at the lower (or inner) depth
Dp = Depth interval between upper and lower depth in in.
Generally, the results of the investigation showed that the
beams could be salvaged for potential reuse by planing 3 in. off
the top layer and 2 in. from each side layer. This approach would
involve two special areas of precaution. First, in removing the
beams, extra care needs to be taken in handling, since they weigh
approximately 3,000 Ib each, are quite awkward (50 ft long) and
there is little substantial building structure separating them from
occupied spaces below. Second, the milling/planing of the beams
will require collecting dust, eliminating exposure to
workers/public and maintaining a relatively low-temperature
blade. It was determined that formation of more hazardous
byproducts (furans/dioxins) through saw blade temperature ex-
cursions was unlikely, since blade temperatures could be main-
tained below SOOT.
INTERSTITIAL SPACE
The interstitial space is the air space between the floor of the
train shed and a suspended ceiling (functioning as a roof) of the
publicly utilized area below. The interstitial space is "criss-
crossed" by built-up I-beams with heights varying depending on
the portion of the shed floor that is supported by individual
beams (Fig. 4). The floor of the interstitial space is also the ceiling
422 CASE HISTORIES
-------
of the public area below; it is a wood structure covered by several
layers of roofing material, including a sheet metal layer and vary-
ing layers of a thick, flexible roofing felt and a thick, rigid roofing
felt. The number of total layers of felt tar paper can vary from
one to four.
Figure 4
Three-Dimensional View of the Interstitial Space Structure and Support
Remedial Investigation
During the early stages of the remedial investigation, it was
determined that pooled PCB-contaminated liquids existed on
small portions of the floor of the interstitial space, caused by
blocked-up drains at the ends of the troughs (Fig. 4). Since the
area below was used by the public, the presence of PCB-
contaminated liquids in these troughs was considered unaccep-
table and required immediate removal. Tests showed, however,
that no substantial PCB contamination had seeped to areas in-
volving direct contact by the public.
The remainder of the remedial investigation included deter-
mination of the extent of PCB contamination of the felt paper on
the floor of the interstitial space and of the PCB-contaminated
deposits and stains on the structural supporting I-beams. Holes
left after rivets rusted out on the top edge of the I-beams were the
main avenues for leaks of PCB-contaminated diesel fuels and
sediment in rainwater to the interstitial space. Generally, for prac-
tical reasons, all portions of the floor which had oil stains were
assumed to have PCB-contaminated deposits and two layers of
PCB-contaminated felt paper beneath them. All I-beams with oily
deposits and stains were marked during the remedial investigation
for the eventual cleanup. The remedial investigation was
hampered by extreme difficulty in access because of such
obstacles as 1-ft high clearances, the need for continuous use of
artificial lighting and the requirement that work be performed only
at night.
CONCLUSION
Considerable tune and financial savings (perhaps 50%) were
realized by the property owner through the development of
statistically significant mathematical models during the site investi-
gation. Several of these models were developed further and en-
hanced by testing several separation techniques for PCB-contamin-
ated rock and soil. It is anticipated that the property owner will save
at least $500,000 during the cleanup phase, depending on the
disposal option chosen, due to the development of the separation
technique.
The entire investigation has been conducted in a heavily popu-
lated/visible urban location. Protection of the public health, envir-
onment and site personnel has been managed without incident.
CASE HISTORIES 423
-------
Installation of Monitoring Wells
Into Wastes in the Love Canal
Jeffrey S. Picket!
William R. Fisher
E.G. Jordan Company
Portland, Maine
ABSTRACT
Three 2-in. stainless steel long-term monitoring wells were in-
stalled into waste materials in the Love Canal to provide water
level data along the length of the canal. This information, in con-
junction with analyses of soil/waste samples and other water lev-
el data from previously installed instrumentation, allowed an
assessment of the geohydrologic conditions within the canal, de-
termination of the effectiveness of remedial measures previously
undertaken and characterization of waste materials still present.
Drilling and installing the monitoring wells was completed us-
ing conventional hollow stem auger drilling and split-spoon sam-
pling methods. Special site conditions, such as previously im-
plemented remedial construction did, however, pose difficulties
in making borings and installing monitoring wells within the
canal. Some of these difficulties included the following:
• Penetration of a subsurface synthetic liner over a clay cap and
repair of the synthetic liner after completion of the monitoring
well to preserve liner integrity
• Management of potentially highly contaminated auger cuttings
• Protection of the contaminant-free ground surface at each bor-
ing location
• Decontamination of potentially highly contaminated drilling
equipment and tools
To minimize impact to the environment and workers and to
protect and maintain the integrity of existing remedial systems,
the project engineer, in conjunction with state and Federal agen-
cies and its subconsultants, developed and implemented some
innovative but relatively inexpensive procedures and methods for
the installation of the wells. Some of these methods included:
• Use of a high density polyethylene (HOPE) boot system for
access through the canal cap and synthetic liner
• Use of stock tanks and conductor casing to manage auger cut-
tings
• Use of HOPE and plastic as a spill containment liner system
beneath the drill rig
• Use of specially adapted decontamination procedures
INTRODUCTION
The purpose of this paper is to present a case study of one seg-
ment of an extensive and on-going study of the Love Canal and
Love Canal Area. The paper does not detail the findings of the
study; rather, it presents methods and procedures used to install
monitoring wells into the Love Canal, a potentially highly con-
taminated subsurface environment.
As part of the Love Canal Long-Term Monitoring Program
Implementation Project, the Jordan Company installed three
monitoring wells in waste materials in the Love Canal at Niagara
Falls, New York. The installations were performed in coopera-
tion with and for the New York State Department of Environ-
mental Conservation (NYSDEC) and the U.S. EPA.
The objectives of the canal wells, in conjunction with other in-
strumentation installed during the project, were to:
• Determine fluid levels within the former canal to be used in the
evaluation of the effectiveness of a barrier drain and the effec-
tiveness of the synthetic and clay cap in controlling fluid in-
flux
• Provide information regarding the nature and integrity of geo-
logic deposits immediately below the waste materials
• Provide samples of soils and wastes for analysis to allow char-
acterization of these materials along the length of the canal
BACKGROUND
The Love Canal site is located near the Niagara River on the
eastern limits of the City of Niagara Falls, New York (Fig. 1). The
area consists of largely abandoned single and multi-family resi-
dential housing within the Love Canal Emergency Declaration
Area. The canal is bounded by Frontier Avenue to the south,
96th Street to the west, 100th Street to the east and Colvin Boule-
vard to the north (Fig. 2). These boundaries enclose an area ap-
proximately 3,000 ft long and 600 ft wide.
Major remedial actions and construction carried out at the site
to date have included:
• Installing a perimeter barrier drain around the former canal
to control the potential for lateral contaminant migration away
from the canal
• Building and operating a treatment plant to treat leachate
collected by the barrier drain system
• Establishing a clay cap over the canal area
• Extending the 300-ft-wide cap constructed to the outer edges
(furthest from the canal) of 97th and 99th Streets using a syn-
thetic 40-mil-thick High Density Polyethylene (HOPE) mem-
brane and a silty clay cover
• Installing a security fence
Presently, the cap on the canal creates a mound about 9 ft high
along the center of the canal which slopes gently to the east and
west edges. The boring and well locations (Fig. 2) were situated
at the top of the canal cap along the approximate centerline of
the canal. An interpretive cross-section (Fig. 3) depicts the gen-
eralized configuration of the canal, cap and barrier drain.
One aspect of the Long-Term Monitoring Program Implemen-
tation Project required Jordan and its subconsultants to devise
methods to efficiently and safely install 2-in. diameter, stain-
less steel monitoring wells in the wastes in the canal. To date,
three wells have been installed in the canal. The locations of the
424 CASE HISTORIES
-------
-XIACJH4 unfit
Figure 1
Site Location
Figure 3
Interpretive Cross-Section—Love Canal
borings and wells, the previously constructed remedial work, the
potentially hazardous wastes deposited in the canal and the pub-
lic's concerns about drilling through the wastes have all posed
numerous problems to successful completion of the project.
It was recognized that new methods and procedures address-
ing these problems would have to be developed to successfully
complete the project as proposed. Through a cooperative effort
between NYSDEC, Jordan and its subconsultants, methods were
devised to:
• Access each boring location with a conventional drilling rig
without rutting or damaging the grass, topsoil and silty sand
overlying the canal cap and the HDPE liner
• Penetrate the existing HDPE liner and clay caps in a controlled
manner to preserve the integrity of the cap
APfBOX. SCALE
1*00 FECT
'///////A AFMIOXIMATI UNIT* Of WMTt DCPOMT*
A OANAL lomtm AND WILL
Figure 2
Boring and Well Locations
CASE HISTORIES 425
-------
• Safely conduct boring operations, collect continuous soil and/
or waste samples, and install monitoring wells within the waste
materials in the canal
• Collect and manage cuttings generated from drilling activities
• Protect the clean ground surface at each well location from
being contaminated by subsurface wastes brought to the sur-
face by drilling operations
• Safely and efficiently transport and decontaminate drilling
tools and equipment without dispersing contaminants
DRILLING EQUIPMENT AND PROCEDURES
A CME model 550 drill rig was used at the site to make the bor-
ings and install canal wells. A conventional drill rig of this size
weighs approximately 32,000 Ib and exerts approximately 3,200 Ib
of compressive force at each of ten wheels. To protect the canal
cap and liner from stress and excessive compressive loading, the
drill rig was mounted on the chassis of an all-terrain vehicle
(ATV) equipped with low pressure, high flotation tires. The dis-
tribution characteristics of these tires allowed the ATV to easily
access all canal boring locations without rutting or damaging the
topsoil overlying the canal cap or the HOPE liner.
Hollow stem augers were selected over cased borings as the
means for making the borings at each canal well location for the
following reasons:
• Hollow stem augers were effectively and safely used to make
borings through similar waste deposits at the Hyde Park Land-
fill in Niagara Falls, New York
• Hollow stem augers were used effectively to install other wells
in proximity to the canal during Phase 1 work of the Long-
Term Monitoring Program Implementation Project
• Drilling fluids are not needed, thus reducing the potential for a
spill of contaminated liquid materials and decreasing the vol-
ume of fluids and soils which would have to be managed
• Hollow stem auger borings can be completed relatively quick-
ly, thus, reducing the amount of time the borehole and asso-
ciated cuttings are open to the atmosphere
The canal borings in which canal wells were installed were
made with 4.25-in. I.D. continuous flight hollow stem augers.
Two-foot-long split-spoon samples were collected continuously
beginning approximately 4 ft below the existing ground surface
and through the waste materials until the bottom of the canal ex-
cavation was encountered, which was evidenced by a transition
from waste and fill materials to undisturbed soils.
The continuous, split-spoon samples provided information
related to:
• Previous capping
• The nature of waste materials deposited in the canal.
• The elevation of the interface between the wastes and undis-
turbed soils
• The geologic characterization of undisturbed soils below the
wastes
After undisturbed soils were encountered, an additional soil
sample was obtained using a 2-ft long, split-spoon sampler to
confirm the presence of undisturbed soils. If the sample con-
firmed the presence of undisturbed soils, the boring was termin-
ated.
Monitoring wells were installed in three of the four canal bor-
ings. The canal wells were constructed of 2-in. I.D., schedule 5,
flush joint stainless steel pipe. Well screens consisted of 10-ft
lengths of wire wrap stainless steel with 0.01-in. slot openings.
Upon termination of the boring, a minimal 2-ft layer of benton-
ite pellets was placed in the bottom of the boring to fill the void
left by the sample spoon and to separate the natural soils from
the fill materials. A stainless steel well was then inserted into the
borehole through the hollow stem augers and positioned approx-
imately 2 ft above the top of the lower bentonite seal (Fig. 4).
The annulus between the borehole and the well casing was back-
filled to above the well screen using fine silica sand.
During placement of the sand, bridging occurred in the annu-
lar space between the well screen and the augers. The bridging
appeared to be caused by the highly viscous nature of the non-
aqueous phase liquids (NAPL) that comprise some of the waste
materials present in Love Canal. Bridging of the sand was miti-
gated by withdrawing the hollow stem augers from the borehole
up to the elevation where the NAPL was first encountered and
placing the sand pack in an unsupported borehole. Fortunately,
the boreholes maintained their integrity and did not collapse,
probably due to the viscous nature of the NAPL. A 2-ft layer of
bentonite pellets was placed above the silica sand pack, and the
remainder of the borehole annular space was filled with alternat-
ing layers of sand and bentonite pellets. A surface seal of 2 ft of
bentonite pellets and a 4-ft thick cement/bentonite plug were
placed at each well to inhibit infiltration of surface water.
\-
Figure 4
Typical Canal Well Installation
BOREHOLE SITE PREPARATION
In 1984, when the canal cap was extended and the 40-mil
HOPE liner was placed, an 18-in. combination of "clean" silty
sand and topsoil was placed over the HPDE liner to allow site
access, to protect the liner against the effects of ultraviolet light
and to sustain vegetation. A crop of grass has been established
on the cover material.
Because the cover material was obtained off-site, the cap sur-
face is considered clean; work conducted at the site must main-
tain and protect the clean surface. At most hazardous waste sites
where borings are made with hollow stem augers, cuttings gener-
ated by the augers are allowed to collect on the ground surface or
some type of temporary plastic sheeting before being transferred
to a disposal drum (if required). This method of auger cuttings
management was deemed inappropriate due to the likelihood of
subsurface waste materials contaminating the clean ground sur-
face, as a result of drilling and well installation operations. Prep-
aration of each borehole site required the installation of a HDPE
pipe and boot system to allow penetration of the HDPE liner and
placement of a spill containment system to protect the ground
surface.
426 CASE HISTORIES
-------
HDPE PIPE AND BOOT SYSTEM
Borings in the canal required penetration of the 40-mil HDPE
liner overlying the canal. NYSDEC required that all necessary
measures be taken to protect and maintain the integrity of the
liner wherever it was penetrated by a borehole or well. Numerous
methods for penetrating the liner were proposed, but a system
using a flexible "top hat" section boot of 40-mil HDPE sleeved
over a rigid section of HDPE pipe was selected.
The HDPE pipe and boot system (Fig. 5) was utilized to allow
penetration of the liner by hollow stem augers while protecting
and maintaining the integrity of the liner. The system consisted
of a 12-in. I.D., 13-in. O.D., by 18-in. long rigid sections of
HDPE pipe with a flexible 40-mil HDPE boot sleeved over the
pipe. The purpose of the HDPE pipe was to add rigidity to the
boot while at the same time providing a redundant level of reliable
protection against the infiltration of water if the weld on the flex-
ible boot failed.
Each HDPE pipe and boot was preassembled and installed by
an experienced liner subcontractor. Access to the liner was gained
by carefully hand-excavating approximately 18 in. of silty sand
soil overlying the liner. The installation was performed by first
welding the HDPE pipe section to the liner. The 40-mil HDPE
boot was then sleeved down over the pipe and welded to the liner.
The welding was performed using an HDPE hot extrusion weld-
ing gun. The area at the top of the pipe where the pipe was sleeved
over the boot was sealed, made waterproof with butyl rubber and
secured with a stainless steel band and clamp. Each pipe and boot
was manufactured and installed for approximately $350. Depend-
ing on weather conditions, the liner contractor was able to in-
stall three to four boots per day.
SECTION VIEW
HUB EXCAVA1ED MEA REFUED
AFTOt MSTAUAHOH Of MOT
40 MIL HDPE UNE*
-BUTYL MJMEII
WELD ^ * 40M.HDKL
— io"4> in. COWUCTOII CAWNQ
PLAN VIEW
SPILL CONTAINMENT SYSTEM
Primary, secondary and tertiary containment systems were de-
vised to effectively manage the auger cuttings, to protect the
clean ground surface at each proposed well location and to be
compatible with the previously installed HDPE pipe and boot
system.
The primary containment system consisted of a 10-in. I.D., 6-
ft long steel casing and a galvanized steel farm stock tank which
had been modified to fit over the previously installed HDPE
pipe and boot. Prior to drilling, the stock tank was placed over
the HDPE pipe and boot assembly. The steel casing was inserted
through the HDPE pipe and advanced about 3 ft into the soil
below the HDPE liner. The conductor casing was secured to the
drill rig by means of a heavily reinforced steel bracket (Fig. 5 and
6).
The steel casing served as a conduit through which auger cut-
tings could come to the surface. Additionally, the steel casing
protected the HDPE pipe and boot from the rotational forces of
the hollow stem augers. The purpose of the bracket was to pre-
vent rotation of the conductor casing when the augers were ro-
tated.
As auger cuttings were brought to the surface through the con-
ductor casing, they were discharged to and collected in the stock
tank. A rubber or polyethylene bladder was placed around the top
of the conductor casing and extended over the top of the HDPE
boot to prevent auger cuttings from dropping between the stock
tank and the boot. As cuttings accumulated in the stock tank,
they were periodically transferred into 55-gal drums for on-site
storage.
HOU.OW iTIM
Figure 5
HDPE Pipe and Boot System
(Not to Scale)
Figure 6
Section View—Canal Boring Set-Up
The conductor casing, securing bracket and stock tank cost
approximately $400, including materials and labor costs associa-
ted with welding and assembly. The system was designed so that
each component could be disassembled and decontaminated.
Secondary containment of spills was provided by placement of
a 25 ft x 45 ft sheet of 40-mil HDPE at each borehole location
(Fig. 6 and 7). The sheet of HDPE was then overlaid by six 4 ft
x 8 ft sheets of 3/4 in. thick plywood. Four-mil polyethylene was
then placed over the sheets of plywood and HDPE to provide a
third level of protection. Curbs were formed at the edges of the
sheet of HDPE by rolling each edge of the 4-mil polyethylene
around 4 in. x 4 in. wood timbers. The timber curbs created a
reservoir which, in the event of accidental spillage of contam-
inated borehole cuttings or borehole fluids, would contain the
spilled materials and prevent contamination of the ground sur-
face.
The ground protection system also delineated work areas and
CASE HISTORIES 427
-------
areas where specific levels of protective equipment were required
(i.e., level B vs. level C). Upon completion of each boring, the
spill containment control system was disassembled by the drilling
team. The 4-mil polyethylene, including contaminants which had
spilled on it, was rolled up and placed in a SS-gal drum. The
sheets of plywood and HOPE were moved to the next drilling
location and reused, if possible.
Each canal well location was set up at a cost of approximately
$175, including labor and materials. The sheets of 40-mil HOPE,
purchased at a cost of $450 each, were reused for the entire pro-
ject.
•nrroMTi enur MOUT
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AMD COMMMTM CAMM
Figure 7
Plan View—Canal Boring Set-Up
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Figure 8
Equipment Decon Pad & Spray Screen
DECONTAMINATION
The drilling equipment and tools used to install the canal wells
required extensive decontamination prior to use at the next loca-
tion. Decontamination of the drilling equipment was performed
at the heavy equipment decontamination area located at the south
UOU* DM. AND WAtn
art TM AIMM AND TOOL* AT TM
TOOK IHUJftf m POIVVTMVLIM
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Figure 9
Drilling Equipment Decontamination Flow Chart
end of the Love Canal site near Frontier Avenue (Fig. 2). The
decontamination area consisted of a concrete pad which sloped to
a centrally located manhole and a sump which drained to the
barrier drain system. The concrete pad was encircled by bitumin-
ous berms to prevent flow away from the manhole and sump.
Because steam-cleaning was part of the decontamination pro-
cedure and because there tends to be a large amount of over-
spray (as with any steam-cleaning process), a method was de-
vised to control the overspray. A 16-ft high splash curtain was
erected around the equipment decontamination area (Fig. 8). The
splash curtain was constructed of polyethylene tarps supported
by rope and 2-in. l.D. by 12-ft long steel pipes placed in 55-gal
drums of sand topped with concrete. The cost of the materials
for the spray curtain was approximately $500, and the system was
erected with only a few hours of labor by the decontamination
team. Decontamination fluids collected on the concrete pad were
filtered through a sandbag berm placed around the manhole and
discharged to the Love Canal Wastewater Treatment Plant
through the barrier drain system.
When each well was completely installed, the contaminated
drilling tools had to be transported to the equipment decontam-
ination area. Drilling tools used to install the canal wells were con-
sidered highly contaminated and could only be transported to
the equipment decontamination pad within the confines of the
Love Canal perimeter fence. Because no access roads within the
perimeter fence directly accessed the decontamination pad, and
because it was not always necessary to decontaminate the ATV
drill rig, a small farm tractor equipped with a front-end bucket
and hydraulic lift platform was used to transport drilling tools to
and from the decontamination area.
Contamination of the tractor and ground surface resulting
from soil dropping off the drilling tools was prevented by com-
pletely encapsulating the drilling tools with disposable polyethy-
lene or, in the case of small tools, placing them in sealed 55-gal
428 CASE HISTORIES
-------
drums during transport to the equipment decontamination area.
Upon arrival at the decontamination area, the equipment was un-
loaded, the polyethylene was placed in a 55-gal drum and decon-
tamination was completed according to the procedures estab-
lished for decontamination of drilling equipment (Fig. 9).
Because of the concentrated wastes encountered in the canal, it
was concluded that it would be difficult to completely decontam-
inate the drilling tools. As a result, the hollow stem augers, drill
rods, split-spoon samplers and accessory drilling equipment (e.g.,
tape measures, hoes, shovels and wrenches) used to make the
canal borings and install the canal wells were dedicated to and left
on the Love Canal site at the completion of the project.
CONCLUSIONS
Three canal wells were installed in wastes in the Love Canal us-
ing specialized, innovative and relatively inexpensive drilling
methods and procedures. Utmost care was taken to minimize the
impact to the environment and workers and to protect and main-
tain the integrity of the existing remedial systems. This protec-
tion was accomplished by: (1) using an HDPE pipe and boot sys-
tem for access through the canal cap, (2) using stock tanks and
steel conductor casing to manage auger cuttings, (3) using 40-
mil HDPE and polyethylene as a spill containment liner system
beneath and around each drilling location and (4) using contam-
inant reduction decontamination procedures. The above proced-
ures could be adapted for use at other hazardous waste sites.
ACKNOWLEDGEMENTS
The authors wish to thank the New York State Department of
Environmental Conservation for their cooperation with the Long-
Term Monitoring Program Implementation Project and their
contributions to this paper. The authors also wish to thank John
Mathes and Associates for their cooperation and technical assis-
tance.
CASE HISTORIES 429
-------
Ground water Studies, Case Histories
And Applied Modeling
Michael O. Smith
HDR Infrastructure, Inc.
Charlotte, North Carolina
ABSTRACT
Identification and abatement of contaminants in groundwater
has captured the attention of Federal and state regulators and the
public within the last five years. Prior to passage of RCRA, the
impact of accepted waste handling practices under groundwater
resources went largely unnoticed. With the passage of RCRA and
the subsequent 1984 RCRA Amendments, new energies have been
directed at this problem. The evolution of this technology is best
demonstrated by reviewing a case study involving a site investiga-
tion which was conducted to characterize existing contaminate
pathways.
The selected case study involves a manufacturing facility (here-
after referred to as Site A) which included metal finishing opera-
tions. The majority of the metal cleaning performed in associa-
tion with the metal finishing process was conducted within vapor
degreasers utilizing the cleaning solvents trichloroethylene and
1,1,1-trichloroethane. Review of the case study of Site A includes
the use of the computer model "Random-Walk" to evaluate in-
terim groundwater remedial action alternatives. Model results are
presented describing the impact of development of the recom-
mended groundwater recovery system.
INTRODUCTION
Public scrutiny of activities resulting in groundwater contam-
ination has intensified within the last 5 years. As a result, indus-
tries, governmental regulatory agencies and private sector service
companies have intensified their efforts to utilize existing technol-
ogies and, where necessary, develop new innovative approaches
to address the issues associated with proper groundwater manage-
ment. A review of current technologies is presented by examining
a case study of a manufacturing facility having volatile organic
chemical (VOC) contamination of both soils and groundwater,
hereafter referred to as Site A.
Site A involves a manufacturing facility which includes a metal
finishing process. Metal cleaning, which is conducted in associa-
tion with the metal finishing process, was performed within vapor
degreasers and at other miscellaneous stations utilizing the sol-
vents trichloroethylene (TCE) and 1,1,1-trichloroethane (TCA).
It is believed that use of TCE and TCA at Site A began in mid-
1961 and continued until January 1985, and June 1983, respec-
tively. These solvents have since been replaced by alkaline clean-
ers. As a result of past VOC management practices, it is estimated
that approximately 2,200 gal of TCE and TCA have been released
into the soil and have entered the groundwater system. Eight
areas within Site A and two off-site areas have been identified as
potential sources of contamination (Fig. 1). The ten potential
sources are:
• Borrow Pit
• Sludge Lagoons
• Effluent Discharge Pipe
Railroad Area
Front Yard Area
Courtyard Area
Manufacturing Area
Drainage Area
Roadways
Off-Site Sources Not Related to Site A
SITE INVESTIGATIONS
Beginning in 1984, an investigative program was implemented
at Site A to delineate the plume of contaminated groundwater.
To date, the plume delineation program has consisted of install-
ing a network of monitoring wells with subsequent sampling and
analysis to determine the extent and degree of degradation of the
groundwater that has occurred. This investigation was a phased
operation with the initial phase being the installation of on-site
monitoring wells, the second phase being the installation of moni-
toring wells immediately off-site and the third phase being the in-
stallation of a comprehensive ring of outer monitoring wells. This
activity resulted in the installation of a total of 44 monitoring
well clusters.
Monitoring well locations can be separated into 17 on-site and
27 off-site clusters. Each cluster contains two to four wells
screened at different depth intervals. The locations of the moni-
toring wells are shown in Fig. 1. Sampling included determining
the groundwater level and performing groundwater analysis in an
effort to determine plume geometry.
Geologic cross-sections constructed from data obtained during
the site investigation (Figs. 2 and 3) illustrate the hydrogeologic
conditions underlying Site A. Cross-section locations are shown
in Fig. 1. Note that the hydrogeologic system consists of an upper
(alluvial) and lower (Ogallala) aquifer separated by an aquitard.
The "leaky" character of the aquitard permits a hydraulic con-
nection to develop between the two flow systems. The upper
aquifer consists of alluvial material and is approximately 20 ft
thick. The Ogallala formation (a minimum of 400 ft thick) forms
the lower aquifer and consists of interbedded sands, gravels, silts,
clays and sandstone.
The regional water table in the alluvial aquifer is located ap-
proximately 5 ft below the ground surface and ranges from
approximately 6.3 to 10 ft above the Ogallala aquifer, indicating
a potential head difference between the two aquifers. In the alluv-
ial aquifer, regional flow is in the west to east direction. A north-
erly component of flow, however, was observed west of the irriga-
tion canal (Fig. 1) during the summer. It is suspected that this
anomaly was caused by seepage loss from the canal. The flow
430 CASE HISTORIES
-------
CD CD CH CD
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LEGEND
* MUNICIPAL WATER SUPPLY WELL
PROCESS WATCH SUPPLY WELL
OBSERVATION/MONITOR WELL
[T| PRIVATE WELL
Figure 1
Locations of Geologic Cross Sections
SOUTH
SOUTH -SOUTHEAST
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Figure 2
North to South Geologic Cross-Section
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Figure 3
Northwest to South-Southeast Geologic Cross-Section
CASE HISTORIES 431
-------
pattern in the Ogallala aquifer fluctuates, depending upon local
pumping activities and seasonal variations.
ANALYTICAL RESULTS
Following the installation of groundwater monitoring wells,
selected groundwater sampling was performed in April, June and
August 1985, with comprehensive groundwater sampling con-
ducted in November 1985. For purposes of this study, the con-
taminant plume boundary was defined as being where the con-
centration of total VOCs exceeded 10 pg/1. Insufficient data rep-
resentative of lower concentrations were available to properly de-
fine isopleths of lower value.
Results from groundwater sampling conducted within the allu-
vial aquifer found total VOC concentrations of 2,310 and 2,211
ug/1 in cluster site #46, while total VOC concentrations in cluster
site #41 for the same time period were 25 and 35 /ig/1, respec-
tively. These data are not conclusive in determining whether the
reported concentrations originated from Site A or an isolated off-
site source. Two hypotheses addressing this anomaly include:
(1) an intermittent release of contaminants from an active off-site
source; and/or (2) contaminant dilution resulting from use of a
local irrigation canal during one of the sampling events resulting
in the separation of the plume into two zones within the alluvial
aquifer. Should the latter hypothesis prove valid, the plume com-
ponent located east of the canal would continue in an eastward
migration, while the western component is temporarily controlled
and/or diverted to a northerly direction.
The southern edge of the plume boundary within the alluvial
aquifer is believed to extend south of cluster site #39. Total VOC
concentrations in this monitoring well cluster ranged from 44 to
47 pg/1. No monitoring well clusters are located south of cluster
site #39; therefore, the plume boundary hi this direction cannot be
defined.
Based upon a review of available analytical data, we concluded
that regional contaminant movement within the alluvial aquifer
appears to coincide with the west to east direction of ground-
water flow. Factors which may affect local plume movement in-
clude pumping from deep production wells. Such actions would
enhance the vertical groundwater movement and may result in
transport of contaminants into the Ogallala aquifer. Further, a
northerly component of flow may develop west of the irrigation
canal during summer months as a result of seepage.
Groundwater samples collected from monitoring well clusters
screened into the Ogallala aquifer showed VOC concentrations in
cluster site #35 (see Fig. 1) of 639 and 949 /ig/1. At depths within
the intermediate Ogallala aquifer (approximately 101 to 170 ft be-
low the surface), VOC concentrations ranging from 660 to 1796
/ig/l in cluster site #26 were detected. Similar to results reported
for the alluvial aquifer, the southern edge of the plume in the
Ogallala aquifer appears to extend beyond cluster site #39 (see
Fig. 1). VOC concentrations of 452 and 8% /ig/1 were identified
at this cluster site.
The northern and western boundaries of the plume within the
Ogallala aquifer are influenced somewhat by municipal wells 53-
1 and 59-1. Groundwater movement in the upper and intermed-
iate zones of the Ogallala aquifer is toward these wells. This ob-
servation is substantiated by the fact that VOC concentrations
ranging from 19 to 28 /tg/1 and 90 to 155 pg/1 were reported at
cluster sites #25 and #26, respectively.
DEVELOPMENT OF REMEDIAL ACTION
ALTERNATIVES
Based upon the results of the site investigations, interim remed-
ial action alternatives were developed. The objectives of the inter-
im remedial action include:
• Contain, recover and treat grossly contaminated groundwater
(VOC levels greater than 500 ii&/\) both on-site and off-site;
• Divert any remaining contamination from the nearby municipal
water supply wells
• Design, construct and operate groundwater treatment systems
capable of meeting multiple discharge limits of 5, 50, 100 and
500MC/1
• Collect information and data resulting from implementation of
the selected remedial action plan to further identify plume
boundaries, monitor plume cleanup and identify any remain-
ing sources
Final remedial action alternatives will be implemented once
additional site investigations are conducted and final permit lim-
its with the appropriate regulating agencies are negotiated.
The recommended remedial action technology assessment, al-
ternative development and screening procedures for Site A con-
sisted of the following steps:
Identify General Response A ctions
• Identify site problems and pathways of contamination (remed-
ial investigation) and define cleanup goals and objectives
• Identify general response actions that address site problems and
meet cleanup goals and objectives
Identify and Screen Technologies and
Develop Remedial Alternatives
• Identify possible technologies in each general response action;
then screen the technologies to eliminate inapplicable and in-
feasible technologies based on site conditions
• Assemble technologies into operable units based on the re-
maining feasible technologies
Screen Public Health, Environmental,
and Cost Factors
• Screen alternatives, eliminating those that have significant ad-
verse impacts or that obviously do not adequately protect the
environment, public health and public welfare
• Screen alternatives, eliminating those that are an order of mag-
nitude higher in cost than other alternatives, but do not provide
significantly greater environmental or public health benefits or
technical reliability
Based upon the above criteria, the general response actions
and associated remedial technologies presented in Table 1 were
considered in developing interim remedial actions for Site A.
Tablet
General Response Actions and Associated Remedial Technologies
General Response
Action
Technologies
No Action
Containment
Pumping
On-Site Treatment
Off-Site Treatment
In Situ Treatment
Some monitoring and analyses
Capping; groundwater containment barrier walls;
bulkheads, gas barriers, hydrodynamic control
Groundwater pumping
Incineration; solidification, land treatment; bio-
logical, chemical and physical treatment
Incineration; biological, chemical, and physical
treatment
Permeable treatment beds; bioreclamation soil
flushing; neutralization; land farming
432 CASE HISTORIES
-------
Since the focus of the remedial action alternatives is to control
the extent of off-site contamination by controlling the primary
transport medium (groundwater), those individual technologies
which specifically address groundwater contamination were con-
sidered next. A summary of specific remedial action alternatives
for contaminated groundwater which were evaluated for imple-
mentation at Site A is presented in Table 2.
Each specific remedial action technology for contaminated
groundwater (Table 2) was next rated and ranked into a relative
order on the basis of engineering feasibility, effectiveness, main-
tenance, service life and cost. Each technology was rated for
each criterion based on a scale ranging from 1 to 10, with a value
of 1 being best and a value of 10 being unacceptable. Results of
this evaluation are presented in Table 3.
Table 2
Summary of Specific Remedial Action Technologies for
Contaminated Groundwater
Application/Restrictions
Technology
Functions
Containment Upgradient from or around
(Impermeable sites, diverts uncontaminated
Barriers) groundwater flow away from
• grout curtain wastes. Downslope or around
• slurry wall sites contains/collects con-
• sheet piling laminated groundwater to limit
extent of aquifer pollution or
protect off-site wells.
Hydrodynarnic Contains or recovers the plume
Control within the radius of influence
of an extraction well. Creates a
hydraulic barrier to ground-
water flow. Allows water with-
in the plume to be pumped,
treated and pumped back into
the aquifer or discharged to a
surface body.
Groundwater Plume containment and/or
Pumping cleanup through pumping
which effectively reverses or
stops the advancement of the
contaminant front. Combines
containment with cleanup of
affected portion of aquifer.
May be combined with re-
charge.
Biological Destroys certain groundwater
Treatment contaminants through bac-
terial activity.
Physical Transfer of volatile organics
Treatment from the water to air through
• Aeration aeration, resulting in treated
water with very low VOC
concentrations.
• Activated Applicable to removal of high
Carbon molecular weight organics, in-
soluble or nonionized organics.
Bioreclamation Bacterial degradation/re-
moval of petrochemical con-
taminants and other organics
as groundwater is recycled be-
tween pump stations.
Applicable to all land disposal
sites and surface impoundments
with groundwater contamination.
Requires expensive preconstruction
geotechnical evaluation, limited to
bedrock depths of under 60 ft.
Compatibility of wastes with
grouts and, to a lesser extent, slurry
walls, has not been fully tested.
Grout not suitable to poorly
permeable soils.
Applicable to containment of
plumes where the boundaries of
contamination are well defined.
Changes in plume volume and site
characteristics result in costly and
frequent monitoring.
Applicable to sites underlain by
permeable, coarse-grained deposits.
No guarantee that the approach will
intercept entire plume of contam-
inated water. Systems are flexible
and can be readily adjusted to ac-
count for changes in the plume.
Applicable to treatment of contam-
inated groundwater containing
higher levels of organics. May be
susceptible to shock loads.
Applicable to treatment of con-
taminated waters containing vary-
ing degrees of volatile organics.
Capable of removing over 99% of
volatile organics from a contam-
inated groundwater.
Adsorption of groundwater con-
taminants by contacting ground-
water with carbon, which selectively
adsorbs hazardous materials by
physical and/or chemical forces.
Not effective for groundwater con-
taminated by heavy metals, certain
chlorinated organics, or other
nonbiodegradables; short-term
treatment only; may be very costly.
Based on the selection criteria used to evaluate the remedial
action alternatives, groundwater pumping in conjunction with air
stripping was selected as the most applicable technology for in-
terim remediation at Site A. Groundwater pumping will address
the primary mechanism (groundwater) by which contamination is
transported off-site. Air stripping will provide for the removal of
VOCs from the groundwater with very low levels remaining after
treatment.
GROUNDWATER MODELING
To evaluate groundwater pumping alternatives and design an
effective recovery system, the solute transport model "Random-
Walk" was utilized. Random- Walk is a two-dimensional model in
which groundwater flow equations are solved using finite-differ-
ence approximations. Model results include identification of the
plume's geometry, movement and contaminant concentrations at
different time periods, i.e., 30 days. The modeling objective was
to provide sufficient information to design a groundwater recov-
ery system to initiate restoration of the aquifers and provide con-
tainment for those areas where VOC concentrations exceed 500
As previously indicated, the Random-Walk model uses the
finite-difference method involving the formation of a grid which
is further subdivided into cells. A particle-in-a-cell and Random-
Walk technique are used in the solute transport portion of the
code to address the effects of convection and dispersion. In Ran-
dom-Walk, a particle is characterized as a dimensionless mass
with a specific concentration which is averaged and distributed
uniformly throughout a cell. The model may be used to simulate
time-varying pumpage, well injection, man-made or artificial re-
charge and the interaction of flow between surface water and
groundwater.
For modeling purposes, the alluvial and Ogallala aquifers were
treated as a single homogeneous aquifer and subdivided into four
zones. Random- Walk does not allow for separation of the aqui-
fers. The zones described above include the screened intervals of
the monitoring wells at 0 to 30 ft, 31 to 100 ft, 101 to 170 ft and
171 to 430 ft. These four zones were chosen because they provide
the best overall data for determining the total mass of the plume.
The following are assumptions which were incorporated into
the Random- Walk model for each of the four zones:
• Aquifer system is homogeneous-isotropic
• Aquifer system is confined and non-leaky
• Storage coefficient, transmissivity and hydraulic conductivity
were computed assuming a discharging well penetrating the en-
tire thickness of the aquifer
• Instantaneous removal of water with decline in head
• The irrigation canal was treated as a constant head boundary
using the image well theory. This theory is a means of develop-
ing an artificial recharge boundary. This canal was not mod-
eled during non-flow periods because it does not cause any
changes in groundwater and/or contaminant movement under
these conditions.
• Longitudinal and transverse dispersion were estimated to be 30
and 3 ft, respectively, where longitudinal dispersion is generally
ten times larger than transverse dispersion
• Half-line or biological breakdown of the contaminants was
considered to be minimal; this assumption represents a worst
case situation
Input to the model was based on data from previous reports
addressing the results from a 73-hr pump test on process water
supply well M-3 located on Site A property. Even though well
M-3 is screened in the Ogallala aquifer, it was assumed that sim-
ilar hydrologic characteristics would also be observed in the allu-
vial aquifer. Further, the hydrologic characteristics from the allu-
vial aquifer were not used as model input for the following rea-
sons:
• Available input data for the alluvial aquifer are incomplete.
Additional parameters (i.e., transmissivity, storage coefficient)
CASE HISTORIES 433
-------
Table 3
Comparison of Remedial Technologies
TECHNICAL
FEASIBILITY PERFORMANCE
SLURRY HALLS
GROUT CURTAIN
SHEET PILING
HYDRODVNAMIC
CONTROL
GROUNDHATER
PUMPING
PERMEABLE
TREATMENT BEDS
BIOLOGICAL
TREATMENT
AIR STRIPPING
CARBON
ADSORPTION
BIORECLAMATION
10
10
10
6
3
«
5
2
4
5
6
8
5
6
3
4
i
1
S
3
MAINTENANCE LIFE
2
2
2
S
S
2
8
4
S
4
1
1
1
5
3
3
3
4
4
3
lERTIcT
COST
9
9
7
S
4
9
S
3
4
i
TOTAL
28
30
2!
27
18
28
26
14
22
21
are needed to initiate model simulations. A pump test is recom-
mended.
Since the mass of contamination is greater in the Ogallala, it is
reasonable to use transport characteristics of the Ogallala as
model input to predict movement of contaminants.
A condition of the model (uniform-homogeneous aquifer sys-
tem) prohibits the use of values from two separate aquifers.
A list of initial input data used in the Random-Walk model is
presented in Table 4. Note that the retardation coefficient listed
as input data is a ratio of travel times between the solute and the
contaminant. Half-life, which is also an input parameter, is the
time required for the biodegradation or breakdown of contami-
nants.
Table 4
Initial Input Data for Solute Transport Model
Parameter
Transarisslvlty
Storage Coefficient
Hydraulic Conductivity
Poroflty
Longitudinal Dlsperslvlty
Transverse Dlsperdvlty
Regional/* -Flow
Reglonal/Y-Flov
Average Aquifer Thickness
Retardation Coefficient
Half-life of Contaminant
Starting Mass Per Particle
Value
91300
0.0004
500
0.30
30
3
0.30
0.003
42S
1.5
1E32
4.98
Gallons
~
Gallons
—
Feet
Feet
Un1t(s)
per day per foot
per day per square foot
Feet per day
Feet pei
Feet
—
Days
Pounds
r day
A map illustrating the proposed layout for the solute transport
model is presented in Fig. 4.
A grid size of 200 ft by 200 ft was chosen to depict the areal ex-
tent of the plume.
Groundwater quality data were next input into the model. To
accomplish this, contaminate concentrations 0
-------
• Compute the particle mass of the plume in each aquifer zone
by assigning a value to a cell in the model; the total mass of the
plume is computed by summing the particle mass in each cell
• Divide the total particle mass of the plume system by the num-
ber of particles to obtain the starting mass per particle
The following equation was used to convert a concentration to
amass:
Mcell = Ne * M * CAVG * RT * AX * AY * Ci * C2 (1)
Where:
Mcell
Ne
M
CAVG
RT
AX.AY
Cl,C2
= Mass of cell, g
= Porosity
= Thickness of aquifer zone, ft
= Average concentration for cell, jig/1
= Retardation coefficient
= Cell side lengths, ft
= Conversion factors
Following input of all initial data into the model, four different
alternatives (i.e., A, B, C and D) were simulated. Each alterna-
tive involved different numbers of recovery wells, recovery well
locations and discharge rates assigned to the recovery wells. The
results of the model simulations for each alternative scenario pro-
vided information which could be used as a basis to design the
groundwater recovery system. Process well M-3 was considered a
fixed recovery well in all simulations.
CONCLUSIONS
Alternative D, consisting of three recovery wells (RC1, RC2
and RC3), was selected as the most effective remedial design be-
cause of its ability to limit plume movement and effectively re-
duce the total mass of the plume. The discharge rates of these
wells were designed to be 846,000, 1,080,000 and 864,000 gal/
day, respectively. Fig. 4 shows the locations of the proposed re-
covery wells.
Eight different model runs or simulations were made using this
alternative. Simulation times ranged from 1 day to 5 yr (Table 5).
The initial geometry of the plume and total VOC concentrations
within the plume were simulated using an interval of 1 day. The
total number of system particles in this simulation was 4086.
After 30 days of simulation, model results indicated a 5.9"% re-
duction in the total mass of the plume. Simulation times were
chosen at random. Subsequent simulation times of ISO, 330,
730 and 1825 days showed 28.44%, 44.5%, 64.32% and 86.88%
(5 yr) reductions in total plume mass, respectively.
Additional information computed by the model includes the
drawdown effects caused by pumping the recovery wells. The re-
sults are an estimation of the amount of head loss or the level,
in feet, which the water table will be lowered in the area. The es-
timated drawdowns in recovery wells (RC2 and RC3) were 18 ft
and 13 ft, respectively. These drawdowns will occur immediately
upon startup of the system. These values do not appear to change
with time. Estimated head losses in municipal wells 59-1 and
67-1 ranged from 1 to 2 ft, approximately 3 ft in wells 53-1 and
65-1 and 3 ft in Site A process water supply well M-3.
Table 5
Results of Interim Groundwater Modeling
Alternative D, Recommended Alternative
Simulation
(Days)
1
30
90
ISO
210
270
330
450
570
690
730
913
1095
1460
1825
Number of
M-3
„
15
78
130
148
27
32
54
38
29
6
45
49
87
51
Particles
RC1
200
200
419
8542
1019
142
110
193
120
128
33
140
97
162
114
Removed
RC2
„
25
107
180
253
43
44
80
70
51
8
46
39
53
39
Total System
Particles
4086
3846
3242
2924
2666
2454
2268
1941
1713
1505
1458
1227
1095
740
536
X Particles
Removed
__
5.90
20.66
28.44
34.76
39.95
44.50
52.50
58.08
63.17
64.32
70.00
73.20
81.89
86.88
Alternative D will provide for the partial containment and res-
toration of the alluvial aquifer. Since the purpose of the interim
phase is protection of drinking water supplies, emphasis was
placed on containment of contaminants and restoration of the
Ogallala aquifer. Equal emphasis will be concentrated on each
flow system for the final remediation phase. Based upon the in-
formation supplied by the Random-Walk model, appropriate air
stripper designs now can be developed.
ACKNOWLEDGEMENT
The following individuals are cited for their assistance in prep-
aration of this paper: Bruce Larsen, John Markey, Bruce Wood
and Mike Harris.
CASE HISTORIES 435
-------
The NIKE Missile Site Investigation Program
Steven L. Shugart, P.G.
Louis S. Karably, P.E., P.G.
Harold T. Whitney, Ph.D., P.E.
Law Environmental Services
Atlanta, Georgia
ABSTRACT
The U.S. Army's NIKE missile system was built to provide pro-
tection from aerial attack to major military installations as well as
key metropolitan areas from approximately 1955 to 1975. During
this period, 292 missile sites were operational in the continental
United States. Operations at the sites required assembly, main-
tenance and storage of components of military hardware as well
as handling, disposal and storage of fuels, cleaners, solvents,
hydraulic fluids and other materials necessary to maintain a NIKE
missile battery operation.
As with any use of military or industrial hardware, the genera-
tion of hazardous waste materials was a typical byproduct. Be-
cause of past waste management practices, the Army wished to
determine if environmental degradation was occurring at these
sites. To investigate this possibility, provisions of the 1984
Defense Appropriations Act were implemented to permit the
Defense Department to include specific, formerly owned, NIKE
sites for investigations.
The role of the Huntsville Division of the Corps of Engineers
was that of central manager during the inventory phase of the
DERP. Further studies, if required, would be the responsibility of
HND for ordnance contaminated sites, and would be the respon-
sibility of the Missouri River Division for hazardous and toxic
contaminated sites.
This paper presents background information on the NIKE
missile program, describes a typical site layout, presents general
information about the site operations and briefly discusses some
of the site-specific findings from 11 sites that have been in-
vestigated by Law Environmental Services. Data from nine of the
11 sites have been evaluated, and results indicate that little con-
tamination was evident in the monitoring wells, soil and surface
water samples associated with the sites.
INTRODUCTION
The Department of Defense (DOD) conducts a number of in-
dustrial processes and manufacturing operations that are similar
to private industry. In the late 1970s, DOD became aware of the
negative impacts of what previously were considered acceptable
disposal practices of waste materials associated with these pro-
cesses and operations. In response to that knowledge, programs
were developed between 1975 and 1978 by each service component
to identify and assess potential contamination on active military
installations. Authority to address problems at formerly used
DOD sites was lacking since funds could not be spent on sites not
owned by DOD.
The passage of the 1984 Defense Appropriations Act corrected
this situation. Specific language in the Act directed DOD to ex-
tend its efforts to include sites formerly used by DOD and
broaden the definition of "hazard" to include unsafe structures
and debris which were to be abandoned or had been abandoned
upon termination of their military use. The Act directed that the
Secretary of Defense assume overall management of the program
to assure a consistent approach and adequate resource allocation.
The objective of this investigation was to assess the potential
for toxic or hazardous contamination related to all former NIKE
missile sites located throughout the continental United States
(CONUS). Contamination included hazardous or toxic sub-
stances found in the groundwater, surface water and soil, with
contaminants specified by regulatory criteria. To fulfill this objec-
tive, a two-phase program was developed. Phase I involved a
generic study of the NIKE program that included the following
work elements:
• Review NIKE site listing forms
• Determine agencies involved with the NIKE battery
• Perform archive search to obtain technical manuals, training
manuals, operating procedures and field manuals
• Meet with previous NIKE site operators
• Review USATHAMA reports to assist in documenting con-
taminant sources at NIKE installations
• Locate "As-Built" drawings
• Obtain generic and site specific deactivation plans
• Prepare a hazardous substance list
• Identify potential contamination sources
• Identify hazardous operational practices
Phase II of this investigation involved specific field investigations
and analytical programs at selected NIKE sites across the United
States. The following sections of this paper briefly describe the
NIKE program background, typical operating units at NIKE
sites, potential contamination source areas and potential con-
taminants at NIKE sites. Finally, the paper briefly discusses some
of the site-specific findings from nine of the sites that were in-
vestigated.
NIKE PROGRAM BACKGROUND
NIKE Ajax and NIKE Hercules missiles were deployed by the
United States Army throughout the continental United States to
protect major metropolitan areas and strategic military installa-
tions from aerial attack. The NIKE system was generally opera-
tional from the early 1950s to the mid-1970s. Maintenance of the
missile batteries in a combat-ready status required the storage,
handling and disposal of missile components as well as solvents,
fuels, hydraulic fluids, paints and other materials required for
support functions.
During the period of its operational life, the NIKE Ajax system
remained essentially unchanged. However, a second generation
436 CASE HISTORIES
-------
NIKE system, NIKE Hercules, was under development by the
mid-1950s. NIKE Ajax batteries were similar in design and con-
struction with all units having similar operational components.
Beginning in late 1958, selected NIKE Ajax batteries began con-
version to the more advanced NIKE Hercules system. However, it
was not until early 1964 that the last NIKE Ajax battery was deac-
tivated and the entire operational system employed the NIKE
Hercules missile. The primary role of.the NIKE Hercules system
was its ability to attack high-speed, high-flying aircraft forma-
tions with a single nuclear warhead. The NIKE Ajax system used
liquid fuels which were highly toxic and had to be handled with
extreme care. The NIKE Hercules missiles made more use of solid
fuel which significantly simplified the fueling and maintenance
operations of the missile system.
In 1962 the Army began transferring operation of certain NIKE
batteries to National Guard units. Shortly thereafter, deactivation
of NIKE, batteries began. By 1970, the Army had deactivated
more CONUS NIKE sites. National Guard units continued to
maintain a few sites until the late 1970s. Some NIKE equipment is
still retained in Ft. Bliss for training troops from other North
Atlantic Treaty Organization (NATO) countries that still incor-
porate NIKE missiles in their defense programs.'
NIKE SYSTEM DESCRIPTION
A NIKE site typically consisted of two separate and distinct
operating units. These units included the Launcher Area and the
Integrated Fire Control (IFC) Area. The Launcher Area generally
was located on approximately 40-60 acres, although each site
could vary significantly in size and shape. The IFC Area generally
PUMPHOUSE O
ASEPTIC TANK
I LEACHING WELLS
DRAINAGE CULVERT
/SEEPAGE PIT
/ /UNDERGROUND STRUCTURES
PESTICIDE
STORAGE
WASH
ACID NEUTRALIZATION
|1 O PUMPHOUSE
QOO Q GUARDHOUSE
£3 rnMISSILE ASSEMBLY BLDG.
AERATOR D STORAGE BLDG.
^ BLDG. \
20
Figure 1
Typical Site Plan for a NIKE Launcher Area
ranged in size from 10-50 acres. The Barracks facilities were either
incorporated as part of the Launcher Area or the IFC Area, or a
third separate and distinct Family Housing Area was constructed.
The Launcher Area and the IFC Area generally were located 1-2
miles apart to facilitate necessary distance and equipment restric-
tions that involved the successful interaction of the two areas.
The layout of structures within each area appears to have been
site-specific, although different sites have many similar struc-
tures. Fig. 1 illustrates a generalized NIKE Launcher Area. For
the Launcher Area, the key structural units include the missile
assembly building, the warhead building and three magazine
(missile storage)/launch units. Although not shown in the figure,
the IFC Area generally included the radar units, a generator
building, general storage and supply buildings and, in most cases,
the motprpool. At some sites, the motorpool could have been
located at the Launcher Area. These sites also generally included
a number of waste disposal units including sump and draining
systems, seepage pits, septic tanks with infiltration wells for liquid
waste disposal and occasionally on-site landfills.
GENERAL UNIT OPERATIONS
The Launcher Area of a NIKE site was the location where the
missiles and warheads were assembled, maintained and prepared
for firing. The missiles arrived at the site disassembled as 13
specific components. All operations necessary to make the missile
flight ready were then conducted in specific locations in the
Launcher Area. In general, routine maintenance and checking
procedures were performed on the missile at the Launcher Area.
The IFC Area at a site contained all the radar, guidance, elec-
tronic and communications equipment needed to identify incom-
ing targets, launch missiles and direct missiles in flight.
POTENTIAL CONTAMINATION SOURCE AREAS
Because of the nature of site operations, several individual
sources of potential contamination existed on former NIKE sites.2j*
The generalized site diagram for the Launcher Area is intended to
indicate the major structural units for reference to areas that
could have resulted in waste. As previously stated, the location of
these units on any given site varied with the terrain and the
general arrangement of facilities.
Waste Fluid Disposal
Probably the most significant general practice that occurred
that could have led to contamination was the method of dealing
with waste fluids. Standard operating practices dictated that
waste fluids were to be accumulated in POL (Petroleum, Oils,
Lubricants) barrels which were periodically transported to
disposal sites. However, waste fluids were reported to have been
disposed of directly to the soil surface on occasion, rather than
being placed in POL barrels, resulting in localized contamination.
The POL barrel contents reportedly have been dumped occa-
sionally in a random "unofficial" manner, both on-site and off-
site. Locations of such dumps are predictable only by general site
characteristics.
Missile Assembly Drainage and Seepage System
The missile assembly building operations involved the use of
various solvents, anticorrosion products and paints as the missiles
were assembled and disassembled. The building was equipped
with a full-length drainage system. Spilled or waste materials
could be washed or dumped into this drainage system.
Diesel and Fuel Oil Storage Tanks
A number of electric power generators reportedly were used on
CASE HISTORIES 437
-------
NIKE 'sites, and diesel fuel storage was considerable. Tanks also
were used to store fuel oil for heating purposes. These tanks were
probably steel, but this could not be documented. It is probable
that several tanks were present at each site, holding up to 5,000
gal each. Leakage from fueling and defueling operations and
actual tank leakage undoubtedly occurred.
Magazine Sump Seepage Systems
Within the typical NIKE magazine, a floor drainage system per-
mitted waste materials to be washed to a central sump located
under the missile elevator shaft. This sump was equipped with a
pump to deliver water and waste out of the magazine and into a
seepage system. Solvents, paints and hydraulic fluid were sup-
posedly washed to the sump on a routine basis.
Secluded Areas Adapted to "Unofficial" Dumping
Dumping of various wastes was reported as common at NIKE
sites. The primary factor affecting the incidence of dumping was
convenience. Certain authorized disposal routes were available to
NIKE sites. However, utilization of these disposal routes varied
from site to site. Solid waste could be delivered to municipal land-
fills while the Army POL service was responsible for removing
waste solvents, oils and paints.
When the landfill was not convenient or the POL was irregular
about pickup, other methods were used to dispose of the waste.
Rural sites were particularly prone to "unofficial" dumping.
Dumping reportedly occurred both on-site and off-site.5'7
Warheading/Fueling Area Drainage System
The potential for contamination in this area is considered to be
less than that found in other areas. Liquid fuels rarely were spilled
in quantities. The IRFNA (nitric acid), UDMH (dimethyl
hydrazine) and ethylene oxide were hazardous, volatile materials
and were handled very carefully. It was very rare that quantities
of these materials escaped accidentally. In addition, due to the ex-
treme reactivity of these substances, any spillage or leakage that
may have resulted in contamination would not persist in the en-
vironment for any considerable length of time.
Battery electrolyte reportedly was discarded in this area,
therefore modest amounts of lead may have been introduced as a
result. However, it is likely that other sources of lead, such as
paint, were of much greater magnitude. Sulfates and nitrates in
the warheading/fueling area would be insignificant in the concen-
trations at which they would occur.
Septic Systems
When barracks were located on the Launcher Area, a septic
system of significant size was required. Urban and suburban
NIKE sites were connected to municipal wastewater systems.
However, rural sites required a septic tank and leaching system.
Barracks were more often sited at the IFC area, along with the
battery administration and other facilities.
Integrated Fire Control (IFC) Area
The IFC Area was less prone to chemical contamination than
the Launcher Area. The diversity of chemicals was smaller, and
the primary mission of the IFC radar operation did not require
significant chemical use. The main units of concern with regard to
contamination at the IFC area were the following:
• Motor Pool
• Septic System
• Diesel, Fuel Oil and Gasoline Storage Tanks
• Secluded Areas Adapted to Unofficial Dumping
Site Deactlvation
No site-specific deactivation plans were obtained. The primary
information concerning deactivation practices came from the site
operator interviews. Two generic deactivation plans8-9 were re-
viewed; however, these plans did not address issues pertaining to
chemicals or practices that may have involved contamination. Ac-
tual practice of deactivation probably resulted in disposal and/or
abandonment of considerable volumes of potentially hazardous
materials according to the site interviews. Specific practices varied
significantly from site to site.
MASTER CONTAMINANTS LIST
Based on the analysis of site operations, a master list of possible
NIKE site contaminants was prepared (Table 1). Each substance
identified on the master list was used in significant quantities on
NIKE sites and has a high probability of causing contamination if
discharged to the environment. Most of the other materials iden-
tified in this investigation were eliminated from consideration
since the volume of use on NIKE sites was small. Certain
chemicals identified in previous investigations conducted by the
United States Army Toxic and Hazardous Materials Agency
(USATHAMA) were not included on the master list. The primary
criteria for not including materials on the master list included:
• The materials were used only in small quantities
• The materials were used with extreme care such that only minor
quantities might have been released
• The materials were reactive to the environment such that pos-
sible contamination from these materials would have dissipated
with time
Specific discussions of the substances comprising the master
list, and of certain significant materials that were eliminated from
the list, are presented in the following section. Materials on the
master list that represent additions relative to previous studies are
so designated.
Table 1
Mister List of Significant Potential NIKE Site Contaminants
use
cwMcnasna
DISPOSAL ICHCD
Evaporation.
ttauaga and uaailnj
Carbon TVtiKtUc* Idt
(QtfOUtM, Qaaa* III,
IV, ml VI)
f*ttol*M uy4ioc.tct.arM
LMd
(CAiboratM *od O«.*)
TOl la.**
lil, 1-Ti ld.loro.tth-.tfM
1 f 1.3-Tr 1 ctUoroa) th*o«
TTid.loro*triyltnt
Qtmtftl Solvent and pu*l OMtituant
DBcorrodlnq Klulla ptrta
Pu«la, bftrlomu.
Paint* and Batttry Electrolyta
Solvent
Solvant
conatttumt of Puola
Sol vint
Solvmt
Solvant
Evaporation,
Drainagt and LaaAlng
Dralnaot an) UaAlng,
SotUot Dlcpaul
Fuel Tw* Ia>akaga,
Splllaot to Sail,
pet. Tura-ta,
Dcainaoc and MKfiuto.,
SurCaoi Dl^oal
Drun»ga and Uadilng,
PCL ftm-ln
Evaporation,
Drajnaoo and Latching
Dralnaot and Lfaditng
putt Tank u-Jin*
evaporation,
Dratnaot and uochlng
Evaporation,
Drainage and Ltadilnj
Evaporation,
Drainage and otaAlnj
Benzene
Benzene was probably in use as a solvent in the early stages of
the NIKE program but was eliminated from updated standard
equipment inventories. It remained in the text of the unrevised
portions of the TM 9-1400-250-15/3 operations manual. Benzene
was removed from military use due to its toxicity.
438 CASE HISTORIES
-------
Benzene is also a common constituent of other solvents and
fuels. Gasoline, for example, contains significant amounts of
benzene, so that NIKE site contamination from leaking fuel tanks
or other solvent use increased the potential for benzene con-
tamination.10"12
Carbon Tetrachloride
As indicated in studies of NIKE sites (USATHMA DRXTH-
AS-IA-83016), carbon tetrachloride was used in the early portions
of the NIKE program. It is a superior solvent and was used exten-
sively for cleaning and degreasing.
Chromium
Chromium originates on NIKE sites in the cleaning materials
chromium trioxide and sodium dichromate, as well as in zinc
chromate and other paints.
Petroleum Hydrocarbons
Fuels, non-chlorinated solvents, naphthas, lubricants, paints
and hydraulic fluid all fall into the class of petroleum hydrocar-
bons. Because there are thousands of different but similar hydro-
carbons, they are considered as a group when dealing with con-
tamination from the materials mentioned above. In sheer quan-
tity, hydrocarbons constitute the most significant potential con-
taminant of former NIKE sites.
Lead
Lead originates on NIKE sites in battery electrolyte and lead-
based paints. Paint disposal at NIKE sites may have caused ex-
tensive contamination by lead.
Perchlorethylene
Interviews confirmed the use of perchloroethylene on NIKE
sites. It was used as a solvent, probably after carbon tetrachloride
use ceased and before the introduction of trichloroethene and
trichloroethanes. High-volume use could be expected during that
period.
Toluene
Toluene was specified as a cleaning solvent for missile com-
ponents. It is also a component of fuels and other solvents.
/, 1,1- Trichloroethane, 1,1,2- Trichloroethane
and Trichloroethene
The use of these solvents was documented previously by
USATHMA and was confirmed by this investigation.
Other Materials Considered
The materials discussed in the following paragraphs are poten-
tial contaminants that were not placed on the master list of con-
taminants for the reasons previously discussed, but which warrant
further discussion because they are mentioned in other source
material as possible contaminants.
Unsymmetrical Dimethyl Hydrazine (UDMH)
UDMH was used in small amounts and stored for use in small
sealed canisters. UDMH was carefully handled and controlled on
NIKE sites. Spills very rarely occurred, and only intentional land-
filling would present a contamination situation. In the environ-
ment, UDMH does not persist because of its reactivity. UDMH
will not occur on NIKE sites, except in sealed canisters, and will
not be found in water or soil samples.
Ethylene Oxide
Ethylene oxide was used throughout the NIKE program as a
fuel for the Accessory Power Supply (APS) system. This system
burned ethylene oxide primarily to power missile guidance
hydraulics. The system was tested periodically with a "hot run."
Waste ethylene oxide was disposed of immediately by burning or
dilution in water and on-site dumping.
Ethylene oxide is a reactive, volatile liquid stored at low
temperatures. (It has a boiling point of 11 °C.) In the environ-
ment, it decays in a very short time. No ethylene oxide remained
as a NIKE site contaminant.
Aniline and Furfuryl Alcohol
These starter fuels were not used in large quantities and pose
very little contamination hazard.
JP-4
JP-4 is a hydrocarbon fuel similar to kerosene. Contamination
by JP-4 is considered along with other fuels under the hydrocar-
bon category.
Low-Level Radiation
Radiation resulting from electrical tube disposal caused ex-
tremely minute contamination with no associated hazard.
Leakage from nuclear weapons did not occur according to knowl-
edgeable sources.
JRFNA (Nitric Acid)
IRFNA was an extremely hazardous material that was handled
with extreme caution by NIKE site operators. Very little con-
tamination via spjllage occurred. The small amounts that were
spilled rapidly reacted to become nitrates. Nitrates occur naturally
in soils and are very commonly used as fertilizer. There is little
chance that serious contamination of NIKE sites occurred as a
result of the use of IRFNA.
Polychlorinated Biphenyls (PCBs)
PCBs were present on NIKE sites in permanent, sealed electric
transformers. Small, random leaks of transformers may have oc-
curred during site operation and after deactivation. Contamina-
tion resulting from PCBs would be small, localized, unpredictable
and unlikely to be discovered except from visual observation of a
leaking transformer. Therefore, PCBs were not included in the
master list for screening during the Preliminary Determination
Phase.
Asbestos
Asbestos may still remain on some sites in its original form in
buildings, on piping and ductwork. It could potentially be re-
moved if demolition occurs at the site. Asbestos was not included
on the master list for screening during the Preliminary Determina-
tion Phase Investigations.
PHASE II PROGRAM
Phase II of the investigation involved field and analytical pro-
jects at 11 specific sites across the United States. Selection of the
sites was intended to provide a broad look at NIKE sites in
distinct geographic regions. Current ownership and use and rele-
vant environmental considerations were factored into the selec-
tion process. Table 2 provides a general description of nine of the
11 sites investigated, each site's general geographic region of the
United States, a brief description of the site and contaminants
observed at the site. The reports of the investigations are under
review by the USA Corps of Engineers and other government
agencies, so specific locations cannot be provided at this time.
CASE HISTORIES 439
-------
Table 2
Phase II NIKE Sllea
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A typical site investigation included the following work
elements:
• Preliminary site visit
• Preparation of site-specific work plans
• Installation of groundwater monitoring wells
• Development of groundwater monitoring wells
• Sampling of groundwater monitoring wells, surface water and
soils at the site
• Chemical and physical analysis of the water and soil samples
• Evaluation of the analytical data
• Preparation of engineering report, including a site hazard rank-
ing system (HRS) report
The analytical program for each site included analysis for
volatile organic compounds, hydrocarbons (diesel and gasoline),
metals and nitrates. Results from the analyses were compared to
applicable water quality standards and criteria and soil criteria to
determine if contamination was present at the locations sampled.
Study Results
The following are generalized results and conclusions derived
from the field investigation phase of the study:
• A general conclusion based on the 11 investigations would be
that the majority of the NIKE sites most likely are not contam-
inating the environment except on a very localized basis. Con-
tamination was only present at a few of the sites and generally
at only a few of the sampling locations. Particular contamina-
tion discovered at the sites included volatile organic com-
pounds near missile silos, diesel fuel near underground tanks
and hydraulic fluid in missile silos.
• Contamination detected at the sites was located around opera-
tional structures such as the missile silos and near underground
fuel tanks related to support units such as the generator build-
ing. However, the contamination appears to be related most
often to inadequate or incomplete deactivation rather than op-
erational practices. For example, an area near an underground
tank showed visible surface contamination of diesel fuel. If
the tank had been properly deactivated by filling, or removed
during deactivation, the contamination probably would not
have occurred. Likewise, hydraulic fluid was present in several
missile silos, either floating on water present in the silos or in
the silo sump. If the deactivation process had removed all the
hydraulic fluid from the units, the contamination most likely
would not have occurred.
From information developed in Phase I and Phase II of this in-
vestigation, it appears that contamination can occur at installa-
tions formerly used as NIKE batteries. However, contamination
does not appear to be widespread at former NIKE sites and subse-
quent investigations should be centered around operational units
such as the missile silos and at support units with underground
fuel tanks. The most likely contaminants will include volatile
organic compounds and hydrocarbons.
REFERENCES
1. USATHAMA, "Historical Overview of the NIKE Missile System,"
Dec. 1984. DRXTH-AS-IA-830I6.
2. USATHAMA, "Assessment of Contamination: Phoenix Military
Reservation Launch Control Area," Aug. 1984. DRXTH-AS-CR-
84296.
3. USATHAMA, "Fulton Property Survey," Dec. 1980. DAAK-
79-C-0148.
4. USATHAMA, "Survey of the former NIKE Site, Bristol, Rhode
Island," Dec. 1980. DRXTH-IS-TR-81088.
5. Personal Communication with five former NIKE site operators.
6. Personal Communication with military radiation safety personnel.
7. Personal Communication with municipal and industry represen-
tatives.
8. U.S. Army. "NIKE Hercules Phaseout Plan," Feb. 1981.
9. U.S Army. "NIKE Hercules Inactivation Plan," Feb. 1974.
10. U.S Army, TM 9-1400-250-15/3. "General and Preventative Main-
tenance Services (NIKE-Hercules and Improved NIKE-Hercuks
Air Defense Guided Missile System and NIKE-Hercules Air Defense
Guided Missile System and NIKE-Hercules Anti-Tactical Ballistic
Missile System)." March, 1968.
11. U.S. Army, TM 9-1410-250-12/1, "Operator and Organizational
Maintenance Manual: Intercept-Aerial Guided Missile MIM-14A
and M1M-14B."
12. U.S. Army, TM 9-1440-252-34, "DS and OS Maintenance of the
Hercules Monorail Launcher, Launching-Handling Rail, Side Truss,
Loading Rack Support, Launcher-Transport Modification Kit,
Launcher-Subsurface Four-Rack Modification Kit, and Launcher
Basis Accessory Kit," Aug. 1960.
440 CASE HISTORIES
-------
Remedial Investigations and Emergency Response
Measures at a Montana RCRA/CERCLA Site
Lena Blais, P.E.
Remediation Technologies, Inc.
Kent, Washington
ABSTRACT
Extensive remedial investigations have been conducted at this
northwestern Montana site where a wood treating plant oper-
ated from 1901 through July 1986. Wood preserving fluids have
entered the groundwater, and areas of heavy soil contamination
exist near former wastewater disposal areas. The site is adjacent
to Flathead Lake, thus requiring a study of the waters and biota
of the lake. The lake also serves as the municipal water supply for
the study area. Emergency removal of contaminants which had
accumulated in a pond near the lake was conducted to prevent
washout of oily wastes.
Activities at the site are governed by two regulatory programs
and by three regulatory agency groups. An administrative order
on consent has been signed by Burlington Northern Railroad and
the U.S. EPA to conduct a CERCLA remedial investigation and
feasibility study (RI/FS) at the site, and RCRA Groundwater
Quality Assessment and Closure Plans and issues exist. Both the
state and U.S. EPA RCRA groups and the U.S. EPA Superfund
group are involved in project oversight, review and approval.
INTRODUCTION
Burlington Northern Railroad has been conducting remedial
investigations at this former tie treating plant in Somers, Mon-
tana, since 1984. These investigations have included installing and
sampling 38 groundwater monitoring wells, drilling and sampling
over 100 soil borings and test pits, sampling surface water and
sediment, sampling drinking water from private wells and the
municipal supply, sampling waste, analyzing fish tissue and con-
ducting bioassays. Results have indicated that localized areas of
contamination exist at the site within and adjacent to former
wastewater management structures. The site contains RCRA-reg-
ulated units and has been proposed for inclusion on the National
Priorities List.
During April 1985, the U.S. EPA declared that site conditions
constituted an emergency and ordered the excavation and con-
tainment of contaminants present in a swampy area adjacent to
Flathead Lake, the largest natural freshwater body west of the
Mississippi. Within 1 month, two double-lined impoundments
were constructed, over 3000 yd3 of soil and 100,000 gal of water
were removed and a 500-ft rip-rap dike was constructed along the
shoreline.
Additional site investigations currently are being conducted
under CERCLA and under an RCRA Groundwater Quality
Assessment Plan. The proposed closure of the RCRA facilities is
under agency review, and CERCLA feasibility studies will be con-
ducted.
PROJECT DESCRIPTION
Geologic Setting
The Somers Site (Fig. 1) is bounded on the south by Flathead
Lake, on the west by a slough or former river channel as well as a
federal waterfowl production area and on the east by a bedrock
outcrop.
Figure 1
Burlington Northern Superfund Site and Surrounding Area—
Somers, Montana
The site is located in northwestern Montana within the Flat-
head Valley. The mountain formations in the area are from the
Late Cretaceous period and are composed of Pre-Cambrian sed-
iments, primarily quartzite and limestone. The last glacial ad-
vance of the late Wisconsin age produced most of the lakes,
drainages and moraines in the area. The Flathead arm of glacial
Lake Missoula once covered the entire valley. The silts, sands
and clays which were deposited within the glacial lake are now the
subsurface soils of the study area.
Flathead Lake is the largest natural freshwater body west of the
Mississippi with a maximum length of over 28 miles, a mean
width of 6.5 miles and a coverage of over 117,900 acres. The mean
depth of the lake is 44 ft, and the maximum depth is over 360 ft.
The northwestern bay area near the site is relatively shallow and is
a depositional area for sediments from Flathead River. Kerr Dam,
constructed in 1938 and located at the natural outlet of the lake,
regulates the upper 10 ft of the lake for power generation.
Site History
Wood treating operations have been conducted at this site since
1901. The site has been operated by Burlington Northern Rail-
road since 1971 and by its predecessors or others prior to that
time. Wood preservatives used at this site were zinc chloride
(1901 through 1939), chromated zinc chloride (1940 through 1943)
and creosote/petroleum mixtures (1927 through 1986).
CASE HISTORIES 441
-------
Wastes generated at the Somers facility were comprised pri-
marily of steam condensate from the steam lines used to heat the
preservatives in the treatment process. Originally, a single con-
densate loop existed at the plant. Excessive downtime for boiler
cleaning, however, required that two loops be piped to separate
the contaminated stream from the uncontaminated stream. Con-
densate derived from space and tank heating was returned to to
the boiler, while that derived from the retorts was disposed of as
waste. Until 1971, this waste stream was discharged to an un-
lined lagoon immediately south of the retorts. The lagoon over-
'flow discharged to an open ditch which drained to a swampy area
adjacent to Flathead Lake. A pond formed along the ditch in
these wetlands. The pond sediments were, in areas, essentially
saturated with oils. The presence of the swamp pond and the old
lagoon were the basis of the initial CERCLA investigations.
From 1971 to July 1984, wastes were discharged to a bentonite
lined lagoon located northwest of the retort building. These
waters were first passed into an oil water separator. The primary,
lined lagoon overflowed to a second unlined lagoon. The lagoons
were designed for total evaporation on an annual basis. These
facilities are regulated under RCRA. In July 1984, a renovated
condensate return system was installed at the site which recom-
bined both condensate streams into one loop and eliminated all
process wastewater discharges. Condensate from the retorts then
passed through an oil sensor and, if necessary, was diverted away
from the boiler to an evaporative reclamation system.
Other waste sources at the site were the drippage from freshly
treated charges as they were pulled from the retorts and, to a less-
er degree, the drippage from ties in storage. The vacuum applied
to the charges prior to removing them from the retort minimized
the amount of drippage. Charges were air dried in the drip area
for 8 to 12 hr before being moved for loading or storage.
EMERGENCY RESPONSE ACTIONS
The long fetch of the Flathead Lake Valley causes strong
winds, and winter storms along this lake can be especially violent.
After the winter of 1984, shoreline erosion near the swamp pond
was evident and the concern was raised that another major storm
could engulf this pond and the contaminated sediments in it.
Plans had been submitted by Burlington Northern Railroad to the
Army Corps of Engineers and to county officials to erect an
earthen dike which would contain the wastes in the pond in the
event of a major storm.
Political difficulties arose with the permit at the time. The lake
was beginning its spring rise. In April 1985, the U.S. EPA de-
clared that the site conditions constituted an imminent and sub-
stantial endangerment and Burlington Northern entered into an
administrative order on consent for the emergency removal and
containment of the swamp contaminants.
Plans were developed to excavate the heavily contaminated sed-
iments known to be present in, and adjacent to, the swamp pond,
to backfill the excavated area with clean materials and to con-
struct a rip-rap dike along the shoreline near the pond. Storage
facilities were needed not only for these contaminated sediments,
but also for the contaminated waters that were in and adjacent to
these sediments.
A decision also was made to retrofit the existing RCRA la-
goons at the plant site. The main RCRA lagoon still contained an
undetermined amount of contaminated soils. The secondary or
overflow RCRA lagoon was overgrown with vegetation. Use of a
synthetic liner material, high density polyethylene (HOPE), was
selected as the most appropriate means of retrofitting these
lagoons.
Emergency response site activities began on May 1, 1985 with
the construction of a work pad and roadway into the swamp area.
On May 6, wastes and soils in the existing RCRA lagoons were ex-
cavated and temporarily stockpiled to prepare the lagoons for
lining. Approximately 600 yd3 of sludges and stained soils were
excavated from the main RCRA lagoon. The lining crew arrived
on May 10 and began lining operations the following day. Twelve
days later, over 170,000 ft2 of 60 and 80 mil HOPE liner, drain-
age grid and filter fabric had been installed. One lagoon was con-
structed for the storage of contaminated soils and sediments, and
its design included both a leachate collection system and a leak
detection system. The other lagoon was constructed for water
storage and included a leak detection system.
During the lining operations, a crew was simultaneously work-
ing in the swamp pond to pump and remove free water and to ex-
cavate and stockpile the contaminated sediments. The first loads
of contaminated soils were placed in the lined lagoon on May 23,
and the final loads were transported on June 1. Water was
pumped from the excavation area continually.
Soil excavation limits were based on the macroscopic extent of
contamination. Although appearance alone could be deceiving
given the natural organic swamp soils in the area, the distinctive
odor and staining characteristics of the creosote-contaminated
soils were conclusive indicators. Samples of the excavated soils
and water and of the soils left in place were collected for analysis
of polynuclear aromatic hydrocarbons (PAH) and benzene ex-
tractable organics. On the basis of PAH analysis 96% removal
was achieved while, in terms of benzene extractables, 86% re-
moval was achieved. Upon completion of the waste excavation,
a 500-ft rip-rap dike was constructed along the shoreline.
REMEDIAL INVESTIGATIONS
The remedial investigation work plan negotiated under the
administrative order on consent calls for the following site investi-
gations:
• Sampling and Hazardous Substance List (HSL) analysis of
wastes, groundwater and surface water
• Installation of additional deep groundwater monitoring wells
and quarterly groundwater sampling and analysis
• Surface and subsurface soil sampling and analysis
• Sediment sampling and analysis along Flathead Lake, the
waterfowl production area and the slough
• Surface water sampling within Flathead Lake and the slough
• An evaluation of the potential impacts of air emissions from
the plant
• Sampling and analysis of the municipal water supply and of pri-
vate wells for PAH, down to the ng/1 level
• Sampling and analysis of the tissue and viscera of fish collected
within Flathead Lake
• Bioassay screenings of rainbow trout and water fleas using sed-
iments collected from Flathead Lake
• Evaluation of the potential uptake of PAH by grasses along the
former discharge ditch and the subsequent uptake of PAH by
cattle grazing on those grasses
The U.S. EPA has since requested an amendment to that work
plan to address the sampling and analysis of waterfowl food chain
items (vegetation and benthic organisms) and, based on the re-
sults of food chain samples, potential sampling of the waterfowl.
Prior to issuing the consent order, wastes, groundwater, sur-
face waters, private and municipal water supplies and surface and
subsurface soil samples were collected and analyzed. The follow-
ing summary of the data is derived primarily from these initial
investigations.
Soil Contamination
There is evidence of soil contamination within the original dis-
442 CASE HISTORIES
-------
posal lagoon, along the ditch which carried the lagoon overflow
into the swamp, within the swamp along the former pond area,
along the drip track, in subsurface beach sediments and in a local-
ized portion of the slough. The old disposal lagoon actually con-
tains deposits of white, crystallized naphthalene, and one sample
from the lagoon contained a reported 50% naphthalene concen-
tration. The majority of the contaminated soils along the ditch
and in the swamp pond have been removed. Drip track contam-
ination is restricted to the upper 1 ft or so of soils. Contaminated
beach sediments exist near the former ditch and are located below
3 to 4 ft of clean sediments. One sediment sample from the slough
has been reported to contain elevated levels of PAH and zinc.
This sample was from an area used for black tie storage before
construction of Kerr Dam raised water levels in 1938. An esti-
mated 15,000 yr3 of contaminated soils remain at the site.
Groundwater Contamination
Groundwater at the site is an alluvial water table aquifer with
no overlying confining layer present. Groundwater is relatively
shallow, ranging from 15 ft below ground surface near the RCRA
lagoons to less than 5 ft in the vicinity of the CERCLA lagoon
and ditch; the swamp is a surface expression of groundwater.
Groundwater flows eastward toward the slough in the northern
portions of the site and bends toward the lake as it moves south.
The groundwater gradient in the swamp reverses with lake level
changes. Bailer recovery tests indicate very low hydraulic conduc-
tivities in the range of 10~3 to 10~4 cm/sec for the upper fluvial
sands, 10~4 to 10~5 cm/sec for the lower silts and silty sands,
and 10~5 to 10~6 cm/sec in the clays, silts and sands within the
swamp area.
Trace levels of PAH have been found in the groundwater
throughout the site. Areas of heavy PAH contamination (great-
er than 5 >ig/l) are restricted to those areas that received direct
wastewater discharges. Low molecular weight PAH, particularly
naphthalene, dominate in all groundwater samples. Initial
groundwater samples were analyzed for ng/1 levels of PAH. Such
analyses are now being conducted only on potable water supply
samples for public health assessment purposes. The U.S. EPA
criteria level for carcinogenic PAH is 28 ng/1 at the 10~5 risk
level. No potable samples from the study area have exceeded this
risk level.
Air Contamination
Studies conducted on the potential impacts of air emissions, on
the potential uptake of PAH by grasses and cattle, the analysis of
fish tissue and the bioassays all resulted in findings of no signifi-
cant impact. Air quality within the plant site was within permis-
sible OSHA limits. A literature review of grass uptake demon-
strated that no risk of cattle uptake existed. Fish tissue were free
of detectable PAH. Bioassays found that the sediments collected
from the near shore of Flathead Lake adjacent to the former
swamp pond were non-toxic.
Biological Studies
Negotiations are currently underway on the need for further
evaluation of the potential impact and uptake of PAH on water-
fowl. The U.S. EPA has requested a plan to sample and analyze
waterfowl food chain species and, if these results show a poten-
tial for impacts to waterfowl, to sample and analyze the water-
fowl.
Issues to be resolved include a definition of "significant" con-
centrations in the food chain, the influence of the migratory na-
ture of the waterfowl on any results, and general sampling and
analytical procedures. No U.S. EPA-approved methods exist for
waterfowl analysis, and significant time and money already have
been spent at this site for verification of an analytical method
other than a U.S. EPA-approved method, i.e., the work done to
obtain U.S. EPA approval of the method used for ng/1 level
analysis of PAH in water.
RCRA/CERCLA INTERACTIONS
Project activities periodically shift in emphasis from CERCLA
related investigations and negotiations to RCRA compliance
issues and back again. A brief regulatory history of the site
follows. The RCRA Part B permit application for the site was re-
quested by the state of Montana in December 1983.
In February 1984, the state came to the site and collected soil
samples along the old discharge ditch. Burlington Northern's re-
sponse to concerns subsequently raised by both the State and U.S.
EPA was quite fast tracked. An RI/FS Work Plan was submitted
to the U.S. EPA in April 1984, and a Closure Work Plan was
submitted to the state in May 1984.
The summer of 1984 was a period of intensive field investiga-
tions to characterize the site conditions and to determine the ex-
tent of contamination. The site was proposed for inclusion on the
National Priorities List in October 1984. In November 1984, a
status report and work plan for additional remedial investigations
was submitted to both agencies. Additional discussions and meet-
ings were held with the two agencies, and a RCRA Closure Plan
was submitted to the state in April 1985.
Plans changed drastically with the issuance of the U.S. EPA's
emergency response order and, rather than proceeding with
closure of the RCRA lagoons, the lagoons were retrofitted to
accept the wastes generated during cleanup of the swamp area.
Negotiations then continued with the U.S. EPA on the proposed
CERCLA remedial investigation work plan. An administrative
order on consent to conduct the CERCLA RI/FS was signed in
October 1985, and Work Plan approval was obtained from the
U.S. EPA in March 1986.
In the fall of 1985, transportation of the wastes which had been
excavated from the swamp and placed in the retrofitted RCRA
impoundment began. These wastes were transported to another
Burlington Northern RCRA facility in the state for storage and
ultimate detoxification. In late September 1985, Burlington
Northern was informed that these waste transfers would no long-
er be approved if the Somers facility lost interim status by not
submitting a Part B permit application by Nov. 7,1985.
A Part B permit application was then prepared and submitted
to the state to allow these transfers to continue. Preliminary com-
ments were received on the Part B from both the state and U.S.
EPA RCRA personnel in March and April 1986. As transfer of
the facility wastes was then complete, the Part B was withdrawn
and revised Closure and Groundwater Assessment Plans were
prepared and were submitted in August 1986.
Additional site investigations were conducted based on con-
cerns raised during this preliminary RCRA Part B review. The
question remains of whether or not these additional data can be
incorporated into the CERCLA site assessment as the data were
collected without an approved CERCLA Field Operations Plan.
Attempts to combine the two regulatory programs into one
overall site programs have to date been unsuccessful. RCRA
authority cannot be waived, and a CERCLA consent order has
been signed and is in effect. Implementation of the Hazardous
and Solid Waste Amendments and a recent decision by the U.S.
EPA that RCRA sites will no longer be eligible for CERCLA con-
sideration appears to have opened the option of placing the site
solely under RCRA. This option is being evaluated at this time.
CONCLUSIONS
Investigations conducted at this former wood treating site in
northwestern Montana have demonstrated a localized pattern of
CASE HISTORIES 443
-------
soil contamination and of heavy (greater than 5 jig/1) ground-
water contamination resulting from past wastewater disposal
practices. This localization of the contamination is attributable
in part to the low permeability of the site soils which consist of
sands, silts and clays in a lacustrine environment. Investigations
of other media including private wells, Flathead Lake which
serves as the municipal water supply for the area, air, grasses and
aquatic life have shown no adverse impact from site operations or
past disposal practices. Additional investigations of waterfowl
food chain species and of waterfowl themselves have been re-
quested.
These investigations are being conducted under a CERCLA
administrative order on consent and under a RCRA Oroundwater
Quality Assessment Plan. Plans for closure of the RCRA facility
have been submitted, but RCRA groundwater corrective action
and monitoring issues will remain along with CERCLA feasibility
studies and corrective action issues. Currently, RCRA related in-
vestigations must be part of a U.S. EPA-approved CERCLA plan
to be incorporated into the CERCLA investigation results.
An emergency response cleanup of contaminants within a
swamp area adjacent to Flathead Lake was conducted. Within a
one-month period, two double lined storage lagoons were con-
structed and over 3,000 yd3 of contaminated soils and over
100,000 gal of contaminated water were removed from the
swamp. The area was backfilled with clean pit run gravel, and a
500-ft rip-rap dike was constructed along the shoreline.
ACKNOWLEDGEMENTS
The author wishes to acknowledge and thank Burlington
Northern Railroad for their support and review of this paper.
Data on the site conditions and on the extent and nature of con-
tamination at the Somers site are from project reports generated
by the following groups in addition to Remediation Technolo-
gies: Hydrometrics of Helena, Montana; ERT of Concord, Mass-
achusetts and Ft. Collins, Colorado; and Soil Exploration Com-
pany of St. Paul, Minnesota.
444 CASE HISTORIES
-------
A Third Party Neutral "Validates" an RI/FS
Lisa P. Carson
Bruce Clemens, P.E.
Clean Sites, Inc.
Alexandria, Virginia
ABSTRACT
The objective of this paper is to describe the role and impacts
of a third party neutral validation of a Remedial Investigation and
Feasibility Study. This paper is based on a case study. After de-
scribing the site and the generic approach to validation, the paper
provides the current status of site activities and concludes with a
discussion of the potential impacts of a third-party validation.
INTRODUCTION
A method to speed the cleanup of hazardous waste sites is being
tried at a Northeastern site where a third party neutral is working
with the state and the Potentially Responsible Party (PRP) to ensure
that the Remedial Investigation/Feasibility Study (RI/FS) meets
federal requirements.
The third party neutral, Clean Sites, Incorporated (CSI), is an
independent non-profit organization formed 2 years ago to speed
the cleanup of hazardous waste sites. CSI became involved at the
site in June 1985 at the request of the sole PRP.
The PRP and the state had worked unsuccessfully for 2.5 years
to negotiate an agreement for the PRP to conduct an RI/FS at
the site. In January 1986, the PRP and the state's Department of
Environmental Protection (DEP) signed a consent order under
which the PRP would do a voluntary surface cleanup as well as
an RI/FS. The order requires that the RI/FS be designed to assess
surface and groundwater quality and identify any contamination
not already discovered at the site during two previous studies.
The consent order specifically requires CSI to certify that all the
work conducted in the RI/FS is consistent with the NCP, the
regulatory framework for CERCLA, and other relevant guidance
documents.
The site is not listed on the NPL. Therefore, the U.S. EPA did
not enter into the consent order and the RI/FS is not legally
required to be consistent with the NCP. In fact, the NCP does not
allow the U.S. EPA to evaluate a cleanup study unless it is con-
ducted under an agreement with the agency.
However, the PRP wanted the site's RI/FS to meet NCP require-
ments to assure the study's long-term viability in the event the site
was placed on the NPL in the future. It saw CSI's validation of
the site's RI/FS as a way of helping demonstrate to the U.S. EPA
that the study was consistent with relevant guidances and regu-
lations. The PRP also thought CSI's validation of the RI/FS would
speed its approval, ultimately speeding the cleanup of the site.
In addition, the company wanted a credible, neutral, third party
to assist in further negotiations. For one thing, the company
thought that as a neutral facilitator, CSI could help give the state's
Water Authority, which was intensely interested in, but not part
of, the negotiations, an opportunity to be heard and responded to.
For the state, CSI's involvement offered the hope that the final
product would require less time to review because it would not
require extensive revision. For CSI, the project offered the first
opportunity to use its Technical Review and Compliance division's
expertise in chemistry, biology, hydrogeology and engineering to
validate a site cleanup study.
SITE BACKGROUND AND
REGULATORY HISTORY
Approximately 50% of the surface of the 102.8-acre site con-
sists of five interconnected ponds which ultimately drain into a
lake which is a drinking water supply source for the nearby city
(Figure 1). Several industrial and private wells are located down-
gradient of the site and are possible groundwater receptors.
Around 1900, the PRP acquired a 200-acre parcel of land which
included the site. Over the years, the site was used for a variety
of purposes including the storage and disposal of inorganic and
organic materials from its nearby plants and laboratories.
In response to a request from the state's DEP, the PRP sub-
mitted a report in 1981 on the contamination at the site. The com-
pany submitted a, second phase of the report a year later.
From 1981 to 1982, during part of the period the state DEP and
the PRP were negotiating for the PRP to conduct the RI/FS, the
DEP sampled both on-site and off-site to define sources of con-
tamination. In May, 1984, a U.S. EPA Field Investigation Team
assessed the site for possible placement on the NPL.
To Lake
Scale
1" = 1,000 Feet
Figure 1
Site Location Plan
VALIDATION—A PHASED PROCESS WITH
SEVERAL SEPARATE REVIEWS
CSI realized that for a validation of the RI/FS to be meaningful,
members of its validation team must give constant feedback to the
contractor and responsible parties conducting and managing the
RI/FS. If this were not the case, a PRP could find itself in the
CASE HISTORIES 445
-------
position of having expended as much as 2 years of manpower and
expense in sampling and analytical work only to find that more
sampling or even a second Rl/FS was required to address those
points that were not correctly or satisfactorily addressed in the first
study. Thus, CSI developed a "phased validation" process which
called for CSI to review the contractor's work at several specific
points throughout preparation of the Rl/FS. This would guarantee
high quality end results.
The CSI site Rl/FS validation process, therefore, was divided
into five, or potentially six, phases. CSI would validate the:
• Rl/FS Work Plan which includes site background and the site
sampling plan
• Site Operations Plan (SOP) which includes the Worker Health
and Safety Plan and the Quality Assurance Project Plan for the
site
• Endangerment Assessment which assesses the potential health
and environmental threats of the site before and after potential
remediation
• Initial screening of alternatives for remediation
• Draft Rl/FS which includes a detailed analysis of remediation
alternatives
• Recommended option and conceptual design for cleanup, if
requested by the state and the PRP
CSI's staff members validate Rl/FS with the assistance and
guidance of CSI's Technical Advisory Board. The seven-member
board is chaired by Dr. Morton Corn, of the Johns Hopkins School
of Hygiene and Public Health. Members include experts in
hydrogeology, environmental engineering, toxicology, public
health, bioengineering and chemical engineering.
Validation of each phase proceeds in a prescribed manner (Fig-
ure 2). Upon receiving documentation for any of the above phases,
members of the CSI validation team review the documents and
send their comments to members of the Technical Advisory Board
subcommittee assigned to the site. They also review the documents
and may revise comments by CSI's staff members. The validation
team then passes the revised comments on to the PRPs and their
contractors.
Shortly after all of CSI's comments have been discussed and,
if necessary, acted upon by the contractor, CSI sends a formal
validation letter for that phase of the Rl/FS to both the PRP and
the regulatory agencies involved. The letter describes the extent
to which CSI's comments have been addressed and provides CSI's
formal position as to whether or not that phase of the Rl/FS is
consistent with EPA regulations and guidance.
Validation of Rl/FS
Figure 2
Institutional Relationships in the Validation Process
STATUS OF THE Rl/FS
VALIDATION KFFORT
As of August 1986, CSI had validated the first two phases of
the Rl/FS, the Work Plan and the Site Operations Plan. The state's
DEP approved the Work Plan with some modifications and is
planning to review the Site Operations Plan.
Members of CSI's Technical Advisory Board subcommittee for
the project who have visited the site and commented on the Rl/FS
are Dr. John Cherry, professor and chairman of the Institute for
Groundwater Research at the University of Waterloo, Ontario,
Canada and Kenneth Biglane, environmental consultant and former
director of hazardous response support at the U.S. EPA.
Dr. Bernard Goldstein, professor and chairman, Department of
Environmental and Community Medicine, Rutgers Medical School,
is also a member of the subcommittee and has commented on the
Rl/FS.
Review of the Work Plan
In reviewing the Work Plan, CSI's key concern was to ensure
that the primary hypothesis of the Rl/FS (that the entire site was
in a groundwater recharge zone and therefore contamination would
eventually enter the pond) could be tested. CSI, therefore, recom-
mended the addition of an additional sampling well cluster to prove
or disprove the hypothesis (Figure 3).
CSI also recommended adding cost estimates as part of the
preliminary screening of remedial alternatives, as well as a list of
applicable or relevant standards for the major contaminants.
In the absence of field sampling and screening techniques, CSI
also recommended that at least one sample from each major area
in each medium at the site be screened for the entire Hazardous
Substance List.
CSI also recommended that the laboratory selected to conduct
the various analyses meet the U.S. EPA's Contract Laboratory
Program criteria.
Technical points made by CSI in its Phase 1 validation letter
included some comments and information which the PRP did not
approve. However, in order to maintain its neutrality, CSI is not
obligated to have its correspondence reviewed in advance. CSI's
validation of the Work Plan was made contingent upon adoption
of the items which its technical staff recommended.
Elevation
(MSL)
«£>»,
Pond C Pond D
Federal
Government
Potentially
Responsible
Parties
State
Local
Communities
Figure 3
Hydrogeology of the Site Showing Possible
Groundwater Recharge to Ponds and Lake
Review of the Site Operations Plan
CSI recommended that in the Site Operations Plan the data
quality objectives be modified to reflect data usage, field sampling
techniques be used where possible for screening and the sampling
plan be changed to maintain consistency with the latest U.S. EPA
CLP guidelines.
Schedule for Completing the
Rl/FS and Validation
Soil sampling and preliminary hydrogeological investigations at
the site should be completed in the fall of 1986. Both rounds of
groundwater, surface water sediment and urban drainage sampl-
ing are scheduled to be conducted from October 1986 to July 1987.
The draft endangerment assessment is scheduled for completion
in September 1987, and the initial screening of alternatives is
scheduled for early November 1987. The draft Rl/FS is expected
in early February 1988, and the final report is due by early March
1988. All of these dates are contingent upon timely review and
446 CASE HISTORIES
-------
approval of the documents by all participating parties.
BENEFITS OF VALIDATION
Validating the RI/FS appeared to help break an impasse in
negotiations between the PRP and the state over the PRP con-
ducting the RI/FS. Those negotiations had lasted almost 2.5 years.
A number of draft agreements had been exchanged, but no agree-
ment had been reached.
Another benefit of having assistance from a third party neutral
was that CSI's reviews acted as a built-in quality assurance/quality
control procedure. Site visits by CSI technical advisory board and
technical staff gave new and important perspectives to the prob-
lem and/or proposed solutions.
In the short run, having another party in the approval loop for
a phased FI/FS lengthened the process. However, in the long run,
in terms of gaining the state's approval and in guaranteeing a more
effective RI/FS, it is hoped that CSI participation will actually
shorten the process.
CONCLUSION
The important technical issues in hazardous waste site cleanups
are not black and white. Diverse disciplines such as hydrogeology,
toxicology, microbiology, fate and transport modeling, analytic
chemistry and economics all must be considered to effect a satisfac-
tory cleanup. A third party neutral can examine these issues and
offer impartial judgments.
Further, a third party neutral can help reconcile the potentially
conflicting views presented as local, state and federal agencies
attempt to fashion a site cleanup. PRPs traditionally have not been
effective in establishing a nonadversarial dialogue with local com-
munity action organizations.
Some persons, however, question whether an additional view-
point injected into a complex technical/political issue is an advan-
tage. This concern is reduced in direct proportion to the technical
competence and public accountability of the third party. Above
all, the third party must be perceived as neutral by all involved
parties.
The experience to date at this site proves that CSI can maintain
neutrality in examining an RI/FS. While only time will tell, the
participating parties believe that the result at this site will be a
cleanup program that is environmentally acceptable and
economically achievable.
CASE HISTORIES 447
-------
Remedial Investigation/Feasibility Study,
NOVACO Industries, Michigan
Mary Elaine Gustafson
U.S. Environmental Protection Agency
Chicago, Illinois
Stephen J. Hahn
CH2M HILL
Bellevue, Washington
ABSTRACT
A Remedial Investigation/Feasibility Study (Rl/FS) was con-
ducted at the NOVACO Industries site in southeastern Michigan
in response to a 1979 chromic acid tank leak. The leak con-
taminated groundwater in a shallow aquifer with chromium,
forming a plume that currently occupies approximately 1 acre. An
endangerment assessment of the site concluded that remedial ac-
tions are necessary to prevent the contamination of residential
wells in the area by plume movement or leakage into a deeper
aquifer from which individual residential wells draw water.
The Rl/FS study evaluated two remedial action alternatives
that would clean up the shallow aquifer using extraction wells as
well as a "no action" alternative and an alternative water supply.
The selected remedial action alternative consists of groundwater
extraction and on-site treatment of contaminated groundwater
using an electrochemical cell (primary treatment) and an anion ex-
change process (polishing treatment). The treatment plant is ex-
pected to remove trivalent and hexavalent chromium to below
their respective NPDES permit limits, allowing the treated
groundwater to be discharged to a nearby stream.
INTRODUCTION
In accordance with the National Contingency Plan (NCP), an
Rl/FS was conducted at the NOVACO Industries site to identify
the lowest-cost remedial action alternative that protects the public
health and welfare and the environment. Aspects of the study re-
quiring special attention were a complex hydrogeologic setting,
strict groundwater cleanup criteria and discharge standards re-
quiring a high level of treatment.
Figure 1
Inferred Total Chromium Contamination Distribution
Site Location and Description
NOVACO Industries is located in southeastern Michigan, ap-
proximately 50 mi south of Detroit. The site occupies a 2.6 acre
parcel and is bordered on the north, east and south by residential
areas and on the west by the Veterans of Foreign Wars (VFW)
Post 9656 (Fig. 1).
The geologic profile at the site consists of about 25 ft of glacial
outwash (sands and gravels) with low to moderate hydraulic con-
ductivity overlying limestone bedrock. The upper surface of the
limestone is weathered, creating a 5-ft thick zone of moderate to
high hydraulic conductivity. Beneath the weathered limestone,
there is a thick zone of competent limestone with hydraulic con-
ductivities ranging from very low to very high, depending on the
presence of fractures and solution channels in the limestone.
Groundwater in the sand and gravel/weather limestone zone is
perched on the upper surface of the competent limestone.
Groundwater occurs at a lower level in the competent limestone;
thus, there is a potential for downward leakage from the sand and
gravel/weathered limestone aquifer into the competent limestone
aquifer. Groundwater flows horizontally in both aquifers toward
the northwest.
There are approximately 85 single-family residences located
within one-half mile of the site. In the downgradient groundwater
flow direction and within 1,000 ft of NOVACO Industries, there
are seven residences plus the VFW Post. All of these residences
use individual water supply wells installed in the sand and gravel/
weathered limestone aquifer, in the competent limestone aquifer
or screened across both aquifers.
Site History
A below-grade plating tank located within the NOVACO In-
dustries building leaked an unknown quantity of hexavalent
chromium into the groundwater on or before June 13, 1979.
Within 24 hr following NOVACO Industries' detection of the
leak, hexavaleht chromium was discovered in NOVACO In-
dustries' 20-ft deep well and in the VFW Post's 45-ft deep well.
NOVACO Industries' well is screened in the sand and gravel/
weathered limestone aquifer, and the VFW Post's well is screened
in both the sand and gravel/weathered limestone and in the com-
petent limestone aquifer.
A groundwater extraction and treatment program was under-
taken by NOVACO Industries from July to November 1979. In
addition, NOVACO Industries replaced the contaminated wells
with deeper wells installed in the competent limestone aquifer.
Approximately 122,000 gal of contaminated groundwater were
extracted, treated on-site and discharged into a roadside ditch.
The extraction and treatment program was discontinued by
NOVACO Industries before all the hexavalent chromium had
been extracted from the aquifers.
448 CASE HISTORIES
-------
From 1979 to 1981, the Michigan Department of Natural
Resources (MDNR) and the Monroe County Health Department
(MCHD) monitored the ground water. Hexavalent chromium
concentrations in the contaminated wells declined; however, a
residential well located west of the VFW Post was contaminated.
Like the contaminated VFW Post well, this residential well also is
screened in both aquifers and was replaced by a deeper well in-
stalled in the competent limestone aquifer. Maximum hexavalent
chromium concentrations were measured in the NOVACO In-
dustries well at 940,000 /tg/1. The U.S. EPA primary drinking
water standard for total chromium is 50 /tg/1.
NOVACO Industries was placed on the National Priorities List
(NPL) in September 1983, and the U.S. EPA conducted remedial
investigations at the site in 1984 and 1985. A feasibility study was
initiated in 1985 and completed in 1986,' and a Record of Deci-
sion was signed by the U.S. EPA on June 27, 1986.2
REMEDIAL INVESTIGATIONS
Remedial investigations consisted of an electromagnetic survey,
monitoring well construction, aquifer testing and sampling and
analysis of subsurface soils, groundwater, surface water and
sediments. Sixteen monitoring wells were installed in three drilling
phases, and groundwater samples were taken on four occasions
between April 1984 and September 1985.
The significant conclusions of the remedial investigation were
as follows:
• An approximately 1-acre plume of chromium-contaminated
groundwater is present in the sand and gravel/weathered lime-
stone aquifer with the horizontal limits indicated on Fig. 1.
The apparent center of the plume is located 200 ft west of the
underground tank that leaked.
• Maximum chromium concentrations within the plume were
measured in the VFW Post's abandoned well in December
1984. These maximum concentrations were 3,220 /tg/1 and
2,780 /tg/1 for total chromium and hexavalent chromium, re-
spectively.
• The plume appears to be vertically contained within the sand
and gravel/weathered limestone aquifer; no monitoring wells
or residential wells screened in only the competent limestone
aquifer are contaminated.
• The piezometric water level in the competent limestone aquifer
is approximately 20 ft lower than the phreatic water level in the
sand and gravel/weathered limestone aquifer, indicating that
there is a strong potential for leakage from the contaminated
sand and gravel/weathered limestone aquifer downward into
the uncontaminated competent limestone aquifer.
• Potential pathways for downward leakage between the two
aquifers are limestone fractures, solution channels and im-
properly sealed well casings—all of which are probably present
within the immediate vicinity of the contaminated ground-
water plume.
• Based on measured hydraulic gradients and conductivities
within the sand and gravel/weathered limestone aquifer, the
maximum expected plume migration rate is 40 to 50 ft/yr to-
ward the northwest.
• Chromium concentrations within the plume appear to be de-
clining, as shown in Fig. 2. From 1980 to 1986, the rate of de-
cline was approximately one log cycle every 3 years. By pro-
jecting this trend into the future and applying a safety factor of
1.5 to 2.5, it is estimated that detectable concentrations of
chromium will remain in the plume for the next 13 to 18 yr.
' Declining chromium concentrations within the plume can be
explained by attenuation and dilution processes. However,
the remedial investigations did not include any groundwater
modeling to attempt to quantify these processes.
Figure 2
Projected Chromium Concentration Decrease
ENDANGERMENT ASSESSMENT
Table 1 presents the applicable or relevant requirements, stan-
dards and other criteria for chromium. The major human health
hazard from chromium-contaminated water is through ingestion.
A "worst-case" exposure calculation would assume consumption
of the maximum total chromium concentration measured during
the remedial investigation—3,220 /tg/1. This concentration ex-
ceeds the federal primary drinking water standard, the proposed
recommended maximum concentration limit and all of the U.S.
EPA health advisories.
The maximum hexavalent chromium concentration measured,
2,780 /tg/1, exceeds the U.S. EPA water quality criteria. Also, the
calculated daily intake of hexavalent chromium, 5.560 /tg/1, is
greater than the U.S. EPA acceptable chronic intake of 350 /tg/1
for a 70-kg person.
IDENTIFICATION OF ALTERNATIVES
The feasibility study (FS) identified several remedial action
alternatives based on site-specific goals and in accordance with
the NCP. The alternatives were then screened for technical
feasibility, environmental and public health impacts and costs.
After this initial screening, the following alternatives were re-
tained for detailed evaluation.
• No action
• Groundwater monitoring and alternative water supply
• Groundwater extraction with on-site treatment and discharge
• Groundwater extraction with off-site disposal
AQUIFER CLEANUP CRITERIA
The federal drinking water standard for total chromium is
50 /tg/1. The State of Michigan is authorized to require cleanup to
the background or non-detection level of 5 /tg/1, and the addi-
tional cost to pump to this level is small compared to the initial
cost of cleaning to 50 /tg/1. Considering these criteria, and con-
sidering that currently available groundwater models, site data
and related experience with similar groundwater extraction
systems at other sites do not allow accurate prediction of
chromium concentrations remaining in the aquifer versus gallons
of groundwater extracted, the aquifer cleanup level that was pro-
CASE HISTORIES 449
-------
Contaminant
Total Chromiua
Trivalant ChroaitBl
Haxavalant ChrovluB
Table 1
Applicable or Relevant and Appropriate Requirements and Other Criteria for Chromium
radaral
rriaary
Drinking
Matar
Standard
ProoooDd
Kac«a»anda |ln (hardneu)! * I J6I) Ai • hardneu of 113 m»/l CaCOj. the criterion ii $41 m»/l.
e Criterion dependent on w.l« hardneu according to the equation c (0 1190 |ln (hardneu)l * 3 68«l Al , hardneu of 323 m»/1 CaCOj. the criterion a 4.540 rt/1.
posed for Alternatives 3 and 4 involved a series of milestones as
described below:
• Milestone No. 1: The extraction well system would operate
until SO jig/1 (or lower) total dissolved chromium is achieved in
every monitoring well and extraction well.
• Milestone No. 2: The extraction well system would operate to
remove a second volume of groundwater equal to the volume
of groundwater removed to achieve Milestone No. 1, or until
non-detectable total chromium concentrations (5 pg/1) are
achieved in every monitoring well and extraction well, which-
ever comes first.
• Milestone No. 3: The extraction well system would operate
for an additional period of time depending on the performance
of the extraction well system in achieving Milestone No. 1 and
2. The U.S. EPA and MDNR will participate in the decision
to continue pumping.
Public Health
Based on the endangerment assessment results, Alternative 1
would not protect public health and the environment. Although
Alternative 2 would provide an alternative water supply, it would
not remove the potential threat of the contaminated water
migrating into the competent limestone aquifer. Alternative 3 and
4, on the other hand, would remove the contamination and the
potential threat and would provide adequate protection to public
health and the environment.
Costs
Capita], O&M and present worth costs for each alternative are
presented in Table 3. Capital costs consist of direct and indirect
costs which are summarized in Table 4. Groundwater monitoring.
Table 2
Summary of Detailed Evaluation
DESCRIPTION OF ALTERNATIVES
Alternative 1, no action, would not require any work at the site.
Alternative 2 would monitor the groundwater and provide an
alternative water supply (private wells or a public well system) to
any residents whose wells become contaminated. These alter-
natives would not remove the chromium from the aquifer, nor
would they remove the potential for migration of contaminated
groundwater into the lower competent limestone aquifer.
Alternatives 3 and 4 would extract contaminated groundwater
to below drinking water standards using a network of extraction
wells, following the milestone approach. A groundwater model
indicated six wells would be needed near the center of the plume
to create a drawdown of at least 2.5 ft near the edge of the plume.
Approximately 36,000,000 gal of contaminated groundwater
would be pumped and treated over a 3- to 4-yr period to achieve
Milestone 2.
In Alternative 3, a treatment plant would be constructed on-
site. The treatment process would include electrochemical reduc-
tion, precipitation, filtration and ion exchange polishing units.
The treated water would be discharged by a one-quarter long
pipeline to nearby Indian Creek which flows into Lake Erie. In
Alternative 4, the extracted contaminated groundwater would be
disposed of in the South Monroe County Wastewater Treatment
Plant by way of a one-mile-long pipeline.
EVALUATION OF ALTERNATIVES
Each of the above alternatives was evaluated on the basis of
seven criteria. The results of this evaluation are shown in Table 2
and discussed below.
••tla U •—4/r™r«l aaU<>r
• U r*>llc aaalta
u
r
OulU tlnlaaal kf alactnckaal-
eal ra*»ctla*/laa inaini
iaf la a >i«i«a tacaa*l«ar
laar
Cully lutalM ultk
450 CASE HISTORIES
-------
Alternative Alternative Alternative Alternative
_! 1 3 4_
Table 5
Annual Operation and Maintenance Costs
untr IDurlna ComtracUool
Mguliu pntocUoo of vorkera
Mte BMlth ana n»lroo««jUl
fttantlal (or ao>ene lapacU to
bBMD baalth in* Olpooure to
Ml; oonUaliuUd Mil* Hi the
Md/grmi «juif«r
COT adVerM iapaCtB tO
buaia health froa expoeure to
M»lr CTiraelnateJ veils la ll»o-
it»M ogultw
Institutional Coaaloeratiou
jktta BSD* GnuMvator Protection
Strategy
ttobablr «~u IDPES Derail
(or Indian Crook
Itatta protmtBont requirement (or
UlpoHl at South Koaroo Countr
Capital oo>t IJ1,000'.)
Fmnt north (Jl.OOO1.)
M
•M
H
HA
3
(7
SCO
M7
P
MA
364
133
Note:
NA — Not applicable
P — Positive aspect
N — Negative aspect
0 — Neutral (neither positive nor negative) aspect
groundwater extraction, on-site treatment, well abandonment
and off-site disposal are the primary operation and maintenance
expenses. Table 5 presents the annual operation and maintenance
costs based on a design flowrate of 50 gal/min. The 30-yr present
worth cost is based on a discount rate of 10% and ignores infla-
tion rates and salvage values.
Table 3
Cost Summary
Alternative
1. No Action
2. Groundwater Moni-
toring and Alterna-
tive Hater Supply
3. Groundwater Extrac-
tion to below
Drinking Hater
Standards with On-
site Treatment and
Disposal
4. Groundwater Extrac-
tion to below
Drinking Hater
Standards with Off-
site Disposal
Capital
Costs
-0-
$5,000
$560,000
$264,000
OCM
(total cost/duration)
Present
North
-0-
$112,000/20 yrs
$419,000/6 yrs
$183,000/6 yrs
-0-
$97,000
$887,000
$433,000
Table 4
Summary of Capital Costs
Estimated Capital Costs ($1,OOP's)
General Requiremnts
Abandon Monitoring Hells
Groundwater Extraction Systen
Onilte Treatment Systen
Onslte Discharge to
Sanitary Sewer (Pipeline)
Construction Subtotal
Construction Contingency t 25%
Construction Total
Construction Engineering
Cost • 6%
Total Implementation Cost
Engineering Design Cost
* 10%
Other Costs t 10%
Total Implementation Plus
Engineering Cost
Alternative
2
0.2
3.0
0
0
0
3.2
0.8
4.0
0.2
4.2
0.4
0.4
5.0
Alternative
3
23
3
38
288
0
352
88
440
26
466
47
47
560
Alternative
4
11
3
38
0
114
166
42
208
12
220
22
22
264
Onsite Treatment (Alternative 3)
Labor
Material
Sludge Disposal*
Power
Backwash Disposal
$48,000
6,000
3,000
7,000
16,000
$80,000
Groundwater Extraction (Alternatives 3 and 4)
Monitoring (seven points) $6fOOO
Power 1,000
$7,000
Offsite Disposal (Alternative 4)
$21,000
Groundwater Monitoring (Alternatives 2, 3 and 4)
$ 8,000
Abandon Monitoring Hells
$15,000b
a Sludge assumed to be hazardous and would require special handling and off-site disposal.
b After 20 yrs for Alternative 2 and after 6 yrs for Alternatives 3 and 4
Note: Annual O&M costs are based on 50 gal/min flow, 24 hr/day, 365 day/yr
Performance, Implementability and Reliability
Alternative 1 was not evaluated because there would be no con-
struction involved. Alternative 2 would provide an alternative
water supply (e.g., replacement wells) to affected residences. Re-
placement wells could be installed in less than 1 wk per well using
proven, reliable well drilling techniques.
For Alternatives 3 and 4, extraction wells and a treatment plant
or sewer could be installed in less than 6 mo. The groundwater ex-
traction wells described for Alternatives 3 and 4 are used com-
monly at hazardous waste sites. The treatment plant in Alter-
native 3 is expected to remove hexavalent chromium to below
detection levels. The installation of a sewer in Alternative 4 is also
a proven technology. All three alternatives would require ground-
water monitoring.
Safety
Protection of workers is not expected to be a problem in any of
the alternatives. Level D protection for construction workers
would be required for Alternatives 3 and 4 because extraction
wells would be drilled within the limits of the plume.
Consistency with Environmental Laws
Several federal and state laws and policies apply to the technical
evaluation of the alternatives for NOVACO Industries. RCRA is
relevant because it identifies maximum concentrations for consti-
tuents in the groundwater. The maximum concentration for
chromium under RCRA is 50 mg/1, which is also the drinking
water standard. The Groundwater Protection Strategy (GWPS)
identifies groundwater quality to be achieved during remedial ac-
tions based on aquifer characteristics and use. At NOVACO In-
dustries, the GWPS would require cleanup subject to current
RCRA policy.
The Michigan Environmental Protection Act 127 is a general
act stating that no one shall pollute, impair, destroy or otherwise
cause harm to the environment. The MDNR may conclude that
the NOVACO Industries study area violates this act because the
groundwater is contaminated.
The Water Resources Commission Act 245 authorized the
adoption of water quality standards to be met in all state waters
(including groundwater). The water quality standard to be main-
tained in groundwater is based on a policy of "nondegradation."
CASE HISTORIES 451
-------
Degradation is defined as a change in groundwater quality from
local background conditions. Under the authority of the Water
Resources Commission Act, the MDNR could determine that the
groundwater at the site does not meet the requirements of the act
and require cleanup to background levels.
Alternatives 1 and 2 would not be in compliance with the con-
centration limits under RCRA, nor would they be in compliance
with the GWPS. Alternatives 1 and 2 also could be in violation of
Acts 127 and 245.
Alternatives 3 and 4 would be in compliance with RCRA and
OWPS. Both alternatives would be required to comply with Act
127 and Act 245. Discharge into Indian Creek in Alternative 3
would be regulated by the MDNR through compliance with the
NPDES permit requirements and by federal ambient water quali-
ty criteria. The extracted groundwater under Alternative 4 would
be discharged by a force main and existing sewer to the South
Monroe County Wastewater Treatment Plant. All discharge to
the sewer system is required to meet the pretreatment standards
established by the Monroe Metropolitan Water Pollution Control
System. Alternative 4 discharges would be in violation of these
standards.
ALTERNATIVE SELECTION PROCESS
The major health concern associated with both Alternatives 1
and 2 is that hexavalent chromium might migrate downward from
the upper sand and gravel aquifer into the competent limestone
aquifer. Currently, the lower aquifer contains no detectable
chromium. Most residential wells in the vicinity of NOVACO In-
dustries draw from the lower aquifer.
Additional potential impacts of Alternatives 1 and 2 are that
surface water quality and aquatic life may be adversely affected if
contaminated groundwater migrates into Indian Creek, and that
restrictions may need to be placed on the locations of future
residential wells. Also, Alternatives 1 and 2 would not meet ap-
plicable federal and state regulations, including RCRA, the U.S.
EPA GWPS, Michigan Environmental Protection Act 127 and
the Michigan Water Resources Commission Act 245. For these
reasons, Alternatives 1 and 2 were eliminated.
Alternatives 3 and 4 would clean up the upper aquifer by ex-
tracting groundwater and then either treating the extracted
groundwater on-site with discharge to Indian Creek (Alternative
3) or disposing of the untreated extracted groundwater to the
South Monroe County Wastewater Treatment Plant (Alternative
4). The time required for either alternative to clean up the aquifer
is estimated at 3 to 4 yr.
Both alternatives would remove chromium from the ground-
water and achieve the same level of cleanup within the same time
frame. Alternatives 3 and 4 also provide the treatment and
disposal of extracted groundwater using technologies that are
reliable and protective of public health and the environment.
Alternative 4 has a disadvantage; the initial maximum expected
discharge concentration for hexavalent chromium exceeds the
treatment plant's pretreatment standard (i.e., a discharge concen-
tration of 800 Mg/l versus 5 ng/l allowable). Furthermore, the
treatment plant officials have stated objections to receiving ex-
tracted groundwater from the NOVACO Industries site because
the additional chromium waste load might adversely impact
South Monroe County's current practice of disposing of its sludge
on croplands.
The Feasibility Study and the Record of Decision recom-
mended Alternative 3 for remedial action because it is the lowest
cost alternative that is technologically feasible and reliable and
that effectively mitigates and minimizes damage to and provides
adequate protection of public health, welfare or the environment.
CONCLUSIONS
The RI showed that remedial action is needed at the NOVACO
Industries site to protect public health and the environment from
chromium-contaminated groundwater. The FS considered several
technologies and alternatives that were cost-effective and
technically feasible. The selected alternative would provide
several benefits, including:
• Removal of chromium contamination in the sand and gravel/
weathered limestone aquifer, thus protecting the lower compe-
tent limestone aquifer
• Cleanup time of approximately 4 yr
• Elimination of the potential for public ingestion of contam-
inated groundwater
• Elimination of the need to place restrictions on future well
construction
• Compliance with applicable federal, state and local regulations
including RCRA, the U.S. EPA GWPS, Water Resources
Commission Act 245, Michigan Environmental Protection Act
127, NPDES permit and ambient water quality criteria.
REFERENCES
I. CH2M HILL, "Revised Public Comment Draft Feasibility Study
Report, NOVACO Industries, Temperence, Michigan," April 11,
1986.
2. U.S. EPA, "Record of Decision," June 27, 1986.
452 CASE HISTORIES
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The Soil Chemistry of Hazardous Materials:
Basic Concepts and Principles
James Dragun, Ph.D.
B.C. Jordan Co.
Southfield, Michigan
INTRODUCTION
Increasing technological use of chemicals is one measure of so-
ciety's advancement. However, as chemical usage has increased,
society's and the environment's exposure to chemicals has in-
creased, and a justifiable concern regarding the discovery of
chemicals in our air, surface water, groundwater and soil has
grown.
This seminar addresses only one aspect of the presence of
chemicals in the environment: chemicals in soil and groundwater.
The overall purpose of this seminar is to dispel a commonly held
notion that soil is an inert medium that does not play a signifi-
cant role in governing the behavior of chemicals. Soils are highly
reactive systems that govern the concentrations of chemicals in
groundwater. One must possess an understanding of the basic
principles of soil chemistry in order to understand how soils gov-
ern the concentrations of chemicals in groundwater. In addition,
it is most important to recognize that soil chemistry principles
govern the success or failure of soil and groundwater treatment
technologies as well as the performance and failure of TSD facil-
ities.
SOIL AS A THREE-PHASE SYSTEM
Soil Chemistry can be defined as the study of the behavior of
soil as a complex chemical and the study of the behavior of chem-
icals in soil. In order to properly characterize the soil system, the
soil chemist draws information from numerous fields including
colloid chemistry, geochemistry, organometallic chemistry, radio-
chemistry, analytical chemistry, geology, clay and soil miner-
alogy, soil genesis, soil fertility, soil microbiology, soil physics,
fluid mechanics and hydrology.
The soil chemist views soil as a three-phase system—solid,
liquid and air—in which numerous physical, chemical and micro-
bial reactions occur simultaneously. It is not possible to describe,
let alone discuss, all of the potential reactions that can occur
within these three phases. However, this seminar will discuss in
some detail several common misconceptions about the nature and
extent of these reactions. Also, it will address several common
misapplications of basic soil chemistry principles.
SOIL ORGANIC MATTER
The size of the organic phase of soil can range anywhere from
1 to 8% by weight for topsoil to generally less than 0.4% for sub-
soil. In other words, topsoil can contain as much as 80,000 ppm
total organics; subsoil, as much as 4000 ppm total organics.
Naturally occurring organic phases are comprised of fats, waxes,
resins, carbohydrates, proteins, humified organic matter and
other classes of organics such as:
alkanes
alkanioc acids
alkanols
alkyl alkanoates
alkylbenzenes
alkyl methanoates
alkyl n aphthalenes
alkyl phenanthrenes
methyl alkanones
phthalates
polynuclear aromatic hydrocarbons
The occurrence and concentrations of naturally occurring or-
ganic chemicals within these groups such as benzene, toluene,
xylenes and ethylbenzene will be discussed during the seminar.
The organic phase of soil serves as the primary food preserve
for numerous microorganisms which are responsible for the de-
gradation of organic chemicals that enter into soil-groundwater
systems. The average number of microorganisms found in soils
can be extremely large. For example, the typical agricultural top-
soil contains about 100,000,000 bacteria/gram of soil. Under
optimum conditions, the number of bacteria could exceed
10,000,000,000/gram.
Each microorganism contains within its cell membrane literal-
ly thousands of enzymes which are responsible for performing
over 36 "type" reactions. During the seminar, the type reactions
responsible for the degradation of alkanes, aromatics and chlor-
inated solvents such as PCE, TCE, DCE, DCA, vinyl chloride,
carbon tetrachloride and chloroform will be discussed.
SOIL MINERALS
The inorganic phase of soil is comprised of numerous soil min-
erals. Minerals react with both inorganic and organic chemicals
that enter soil-groundwater systems. With regard to the former,
soil minerals can immobilize metals through "fixation" reac-
tions. Fixation reactions include the formation of chemical bonds
with mineral surfaces (chemisorption), the irreversible penetra-
tion of mineral structures (solid state diffusion) and the precipi-
tation of new soil minerals such as oxides, hydroxides, oxihydro-
xides and phosphates. This seminar will address the nature and
extent over many different soil types of the fixation of at least one
metal.
With regard to mineral reactions with soil minerals, it is most
important to recognize that soil inorganic mineral surfaces can
act as catalysts to increase the reaction rates of chemical oxida-
tion, chemical reduction and chemical hydrolysis. For example,
soil inorganic mineral surfaces possess iron oxides, aluminum
oxides and adsorbed oxygen which can catalytically react with
SEMINARS 453
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organic chemicals present in soil. This seminar will address the few years regarding the presence of bulk hydrocarbons in soil-
nature and extent of at least one major type of surface-catalyzed groundwater systems. The physical reaction of some bulk Hydro-
reaction, carbons with soil will cause a significant increase in soil perme-
ahilitv relative to water This seminar will address the nature and
BULK HYDROCARBON MOVEMENT amuty rcfmtl*e to wa"r' nl? semuuj
THROUGH SOIL PORES extent of so>1 P«™eabibty changes caused by at least one type of
A considerable amount of concern has arisen over the past bulk hydrocarbon, if time permits.
454 SEMINARS
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Rational Approaches to Selecting,
Performing and Interpreting Medical Tests
In a Medical Surveillance Program
Bertram W. Carnow, M.D.
Shirley A. Conibear, M.D.
Carnow, Conibear & Associates, Ltd.
Chicago, Illinois
INTRODUCTION
The hazardous waste work environment presents several prob-
lems that are unique in terms of selecting and carrying out medi-
cal surveillance of workers. Large quantities of a great variety of
hazardous materials are, by definition, present at the work site.
Combustion or reaction products may be present as well as un-
known contaminants which were contained in the original ma-
terial.
The work force is, in general, well trained and well protected
in terms of personal protective equipment, and actual exposures
on a day-to-day basis are probably very small unless some type
of emergency or improper procedure occurs. However, workers
frequently move from site to site and may be potentially exposed
to hundreds of toxic materials in the course of a work year. Since
medical examinations and tests are selected in part to examine the
effects on the target organs of the toxic agents to which the per-
son is exposed, this wide variety of toxic materials exposures
makes test selection a problem.
MEDICAL SURVEILLANCE OBJECTIVES
A number of major objectives are pursued in carrying out med-
ical surveillance. The first is to establish a baseline for an individ-
ual to determine whether there is a body burden of toxic agents
and, also, whether the body itself is healthy. While norms have
been established for many tests, there are large individual differ-
ences within the range of normals and for each individual. Estab-
lishing a baseline is an important way of detecting early trends in
disease, in determining whether illnesses may be work related, in
detecting pre-existing disease before an individual has any ex-
posure and in determining fitness for employment (for example,
the ability to carry out heavy labor in a highly stressful environ-
ment, tolerating heat in an enclosed suit or the ability to wear a
respirator). Another important objective is to comply with regu-
lations for hazardous waste workers.
TESTING
Criteria for determining who to test include examining the
extent and duration of exposure and the protective equipment re-
quired. Other factors to be considered include personal factors
such as age and sex, since endocrine and other functions may be
affected under certain conditions of exposures.
The selection of a test protocol will be considered and examples
presented. They are selected in order to establish individual base-
lines, determine the fitness of the worker and then determine
whether or not there has been undue absorption of toxic agents.
This increase in body burden may exist in the form in which a ma-
terial entered the body or as a breakdown product. The other
major test procedures are those which measure organ function to
determine whether those organs have suffered as a consequence
of absorption.
Determining the test frequency requires examining the intensity
of exposure, the number and types of materials to which work-
ers may have been exposed, the exposure intervals and unusual
situations or emergencies where there may have been heavy ex-
posure or a loss of protection.
A major problem is quality control since individuals may be
working in different parts of the country and may be examined by
a variety of medical facilities or individuals with differences in
techniques, norms and skills. Thus, standardization, accuracy,
reliability, handling and storage of data are critical and will be
discussed with examples.
CONCLUSIONS
Finally, how these data are interpreted and utilized to safe-
guard health will be summarized. These would include a dis-
cussion of their use in an emergency, use for plotting of trends to
allow early detection of disease at a reversible stage and use of
other methods to prevent disease and maintain the health of the
work force. The unique aspects required for medical surveillance
of the hazardous waste worker will be the central theme of the
seminar.
SEMINAR OUTLINE
1. Purpose of medical surveillance
• Establish a baseline
• Detect pre-existing disease
• Determine fitness for employment
• Comply with regulations
• Detect work-related illness
• Detect early trends
2. Criteria for determining who to test
• Extent and duration of exposure
• Protective equipment requirements
3. Selecting a test protocol
• Tests to establish individual baseline
• Tests to determine fitness of worker
• Tests to quantitate toxic materials or their metabolites in the
body
• Tests to measure organ function
4. Determining test frequency
• Intensity of exposure
• Nature of exposure (number and type of materials)
• Exposure intervals
• Unusual situations and emergencies
SEMINARS 455
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5. Quality control issues in a medical surveillance program
• Standardizing data collection
• Accurate, reliable data
• Storage and retrieval of data
6. Interpreting and using medical surveillance data to safeguard
health
• In an emergency, provides baseline information on indi-
vidual norms or pre-exposure levels, special susceptibility
and pre-existing disease
• Routine monitoring over time can show trend toward
abnormality, allowing early detection of disease at a rever-
sible stage and trigger a review of work-place procedures
for preventing exposure and testing of others similarly ex-
posed
• Examinations provide an opportunity to review and rein-
force good health and work practices, answer questions and
allay fears
• Signs of frank disease, either work or non-work related,
can be detected and treated
• Grouped data can be used to detect trends which may not
have been evident in the individual
456 SEMINARS
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Superfund Risk Assessment:
The Process and Its Application to
Uncontrolled Hazardous Waste Sites
Craig Zamuda, Ph.D.
Jim Lounsbury
U.S. Environmental Protection Agency
Office of Emergency and Remedial Response
Washington, D.C.
David Cooper
ICF-Clement
Washington, D.C.
INTRODUCTION
As part of the Superfund program to mitigate problems caused
by uncontrolled hazardous waste sites, the U.S. EPA has adapted
general risk assessment procedures to analyze threats to public
health at those sites. This paper describes the basic components
of the Superfund risk assessment process that address public
health concerns. Illustrations of how risk assessment may be used
in the field are included.
CERCLA authorizes the federal government to respond direct-
ly to releases, or threatened releases, of hazardous substances
that may endanger public health, welfare or the environment.
The National Oil and Hazardous Substances Pollution Contin-
gency Plan (NCP) establishes a framework for implementing
CERCLA by outlining the process for developing and evaluating
various remedial alternatives for Superfund sites. The NCP
describes two major elements of the site remedial planning pro-
cess; the remedial investigation (RI) and the feasibility study (FS).
During the RI, field investigators obtain site characterization data
necessary to determine what responses, if any, should be consid-
ered and evaluated for a site. During the FS, remedial alterna-
tives are developed to effectively address site contamination
problems identified in the remedial investigation.
The Superfund Record of Decision (ROD) summarizes the in-
formation from the remedial investigation and the FS. The ROD
describes the remedial action chosen for a site and how it meets
the requirements for consideration of public health, cost-effec-
tiveness and compliance with RCRA and other environmental
statutes. The RODs include specific cleanup levels for contam-
inated soils and water based on health-based criteria and an eval-
uation of remedial alternatives for a site.
Chapter Five of the Guidance on Feasibility Studies Under
CERCLA (U.S. EPA, 1985) summarizes a method for public
health evaluation at Superfund sites and provides the basis for
the U.S. EPA's Superfund risk assessment process and proced-
ures manual, the Superfund Public Health Evaluation Manual
(SPHEM) (U.S. EPA, Dec. 18, 1985), which describes the pro-
cess. The risk assessment process is based on several EPA docu-
ments that detail major aspects of risk assessment including
guidelines for carcinogenic risk assessment, exposure assessment,
mutagenicity risk assessment, assessment of suspected develop-
mental toxicants (49 FR 46294-46331) and health risk assessment
of chemical mixtures (50 FR 1170-1176), which provides a frame-
work for public health evaluation. The goals of the process are to
ensure that Superfund remedies adequately protect public health
and that the risk assessment process used is consistent. A sim-
ilar guidance has been developed by the U.S. EPA's Office of
Waste Programs Enforcement (OWPE) for endangerment assess-
ments at enforcement-lead sites. This guidance is described in
The Endangerment Assessment Handbook (OWPE, U.S. EPA,
Aug. 1985). To supplement these procedures manuals, critical
chemical and toxicity data from Health Effects Assessment doc-
uments and other U.S. EPA-approved sources for more than 200
chemicals typically found at uncontrolled waste sites have been
summarized in the appendices to the SPHEM.
In developing these procedures, the U.S. EPA recognizes that
public health evaluations cannot be reduced to simple, cook-
book procedures. State-of-the-art risk assessment techniques re-
quire the use of informed scientific judgment. Each site poses a
unique set of circumstances that must be addressed on a case-
by-case basis.
THE SUPERFUND PUBLIC HEALTH
EVALUATION PROCESS
As described in the SPHEM, Superfund public health evalua-
tions are conducted in two phases. The baseline evaluation, which
is a major part of the evaluation, examines the effects of taking
no action at the Superfund site and is initiated early in the remed-
ial process. The second phase involves refining initial design ideas
for remedial alternatives to address specific health concerns at the
site and evaluating the consequences of implementing those al-
ternatives. Environmental concerns also may be important and
may actually drive the cleanup at some sites.* Those consider-
ations are made separately from the public health risk assess-
ment, however.
Baseline Public Health Evaluation:
Assessing Initial Site Conditions
The risk assessment process is a generic framework that is
broadly applicable to many sites. The level of effort required for a
site is a site-specific decision determined in part by the complexity
of the site, number of chemicals present, availability of toxicity
data and necessity for precision of the results. As a consequence
of attempting to cover a wide variety of sites, many of the pro-
cess components, steps and techniques described in the manual
•At the Burnt Fly Bog site, NJ (ROD signed Nov. 16, 1983), NTIS No. PB85
213676/AS), excavation of lagoons and wetlands was undertaken to remove threats
to public health and the environment. However, wetlands will be restored to natural
contours and revegetated based on the environmental considerations of erosion
control and biological restoration.
SEMINARS 457
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will not apply at every site.
The baseline evaluation consists of five steps:
Selection of indicator chemicals
Determination of human exposures
Estimation of human intakes
Evaluation of toxicity
Characterization of risk
Selecting Indicator Chemicals
The Superfund public health evaluation is based on selected
chemicals, referred to as "indicator chemicals," that pose the
greatest potential health hazard at a site. It may be both imprac-
tical and unnecessarily time consuming to assess the risk of every
chemical.
Indicator chemicals are chosen to include the most toxic,
mobile and persistent chemicals, as well as those present in the
largest amounts. For each chemical, toxicity is examined in light
of concentrations measured in specific environmental media. In
addition, various chemical and physical properties that affect the
potential for a substance to migrate or persist in the environment
are considered.
Determining Extent and Duration of
Human Exposures
Once indicator chemicals have been selected, the extent and
duration of human exposure to each contaminant can be esti-
mated. Chronic and subchronic exposures are evaluated for each
human exposure pathway identified at the site using monitoring
data and environmental fate modeling. Details of exposure eval-
uation are given in the Superfund Exposure Assessment Manual
(U.S. EPA, 1986). The results of this step are estimates of long-
term and short-term concentrations of indicator chemicals at all
exposure points.
Comparing Projected Concentrations to
Standards
At this point in the process, the projected concentrations of in-
dicator chemicals at exposure points are compared to "applicable
or relevant and appropriate" environmental requirements estab-
lished in other environmental programs, subject to a few excep-
tions (50 FR 47,975 to be codified at 40 CFR §300.68(i)(l)). Ex-
amples of requirements that the Agency has determined may be
applicable or relevant and appropriate for the purpose of risk
assessment depending on site conditions are Safe Drinking Water
Act Maximum Contaminant Levels (MCLs) and Clean Air Act
National Ambient Air Quality Standards (NAAQS).
In the ROD, a variety of other requirements may serve as the
basis for choosing a final remedial alternative. For example, PCB
waste oils at the Laskin/Poplar Oil site in Jefferson, Ohio (ROD,
8-9-84) were removed and incinerated in compliance with 40 CFR
761 requirements for PCBs under TSCA. At Triangle Chemical,
Texas (EPA/ROD RO6-85-007), RCRA guidelines for tank
closure, floodplain management under Executive Order 11988
and Clean Water Act MCLs were included in the analysis of
remedies.
For some Superfund sites, no applicable or relevant and ap-
propriate requirements may exist for all the selected chemicals.
In these situations, a quantitative risk assessment must be com-
pleted. The final public health evaluation may include both a
standards comparison and a quantitative risk characterization.
Estimating Human Intake
After estimating exposure point concentrations, the assessment
team must estimate the amount (in mg/kg/day) of a substance a
person takes in by breathing contaminated air, drinking contam-
inated water and ingesting contaminated soil. Standard assump-
tions about consumption of air, water and soil are combined
with estimated concentrations in various media to generate in-
take values unless human activity patterns that affect intake are
available. Other human exposure pathways may be developed
in consultation with U.S. EPA headquarters, if necessary for a
specific site.
Evaluating Toxicity and Characterizing Risk
The next step in the process is to evaluate the toxicity asso-
ciated with each chemical. For noncarcinogens, toxicity values are
presented in terms of acceptable intake levels for chronic and
subchronic exposures. For risk characterization, these acceptable
levels are compared to estimated intake levels for potentially ex-
posed individuals. Multiple chemical exposures also are assessed
using an approach based on EPA's proposed "Guidelines for
Health Risk Assessment of Chemical Mixtures" (50 FR 1170-
1176). This approach encourages the assessment team to consider
the cumulative "insult" from a number of chemicals that induce
the same health effect.
For carcinogens, upper bound carcinogenic potency factors
are combined with estimated intake levels to calculate upper
bound confidence limits on carcinogenic risks. The U.S. EPA's
proposed guidelines for mixtures permit the use of "risk addi-
tivity" for carcinogens. This procedure allows estimation of a
total upper bound carcinogenic risk by summing the risks posed
by individual indicator chemicals.
Refining Designs and Evaluating
Remedial Alternatives
Ultimately, remedial alternatives under consideration will be
analyzed with respect to public health and environmental pro-
tection, consistency with applicable or relevant and appropriate
requirements, technical feasibility and cost; and one alternative
will be selected and presented in the ROD. The NCP requires
the chosen remedy to "mitigate and minimize threats to and pro-
vide adequate protection to public health and welfare and the
environment" (50 FR 47,975. to be codified at 40 CFR §300.68
(0(1)].
Consideration of cost is one of the important inputs to the risk
management decision. For example, at the Jibboom Junkyard
site, California (EPA/ROD RO9-85-008) as amended on Oct. 4,
1985, excavation and off-site disposal at an RCRA approved haz-
ardous waste disposal facility was chosen as the selected alter-
native because it reduced soil lead concentrations to below 500
ppm. Removal was chosen over capping, a lower cost alterna-
tive, because of threat of possible groundwater contamination
should groundwater levels in the area rise.
However, providing an alternate water source to replace con-
taminated wells was chosen as the remedial action at the
Matthews Electroplating site in Roanoke, Virginia (ROD,
6-2-83). This option represented the cost-effective remedy that
was protective of public health and the environment. Additional
action at the site (i.e., capping) was determined to be unneces-
sary because it provided no additional public health or environ-
mental protection for the additional expenditure.
At the McKin site, Maine (EPA/ROD RO1-85-009) contam-
inated soil will be cleaned up to levels that are protective of the
groundwater and other potential routes of exposure. Ground-
water monitoring will be conducted to ensure no migration of
contaminants during the remedial activity.
Applicable or relevant and appropriate requirements serve as
the basis for remedies at a site if they are available for chemicals
of interest. If not, a risk-based approach is used. Remedial al-
ternatives are refined as necessary to ensure that options consid-
ered in the ROD span a carcinogenic risk range of 10~4 to 10~7.
Regardless of what risk level is chosen, health risk from potential
carcinogens generally drives the development of performance
458 SEMINARS
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goals for remedial alternatives.
The 10 ~6 carcinogenic risk often is chosen as the target risk out
of the carcinogenic risk range of 10~4 to lO"7. At the Reilly Tar
site, St. Louis Park, Minnesota (ROD, 6-6-84), the ROD specifies
that the 10~6 cancer risk level for polyaromatic hydrocarbons,
the chemicals of chief concern at the site, was chosen as the goal
for cleanup of a contaminated aquifer.
In other situations, other values in the risk range ultimately
may be chosen for the remedial action. For example, at the
McKin site in Gray, Maine (EPA/ROD/RO1-85-009), a 1Q-5 life-
time statistical cancer risk level was chosen for trichloroethylene,
the chemical of highest concern, because of relatively low levels of
uncertainty regarding levels of contamination in the affected
aquifer following 5 yr of monitoring, no known regular human
use of the contaminated aquifer, consideration of natural atten-
uation mechanisms and consideration of the effect of remedial
action at the site.
The 10 ~5 cancer risk level also was chosen for groundwater at
the Old Mill, Ohio site (EPA/ROD RO5-85-018) because that
level can be reached with 30 yr of treatment whereas the 10 ~6
cancer risk level would not be reached for 100 yr. Background
may be chosen as the cleanup level as was the case at Triangle
Chemical, Texas (EPA/ROD RO6-85-007).
In addition to addressing the long-term health effects at a site,
short-term effects of implementation also must be considered for
all remedial alternatives. For example, it may be important to
consider inhalation risks to nearby residents if installation of a
particular technology involves substantial excavation and dust
generation. This evaluation may be qualitative or quantitative and
is used to develop management practices to control releases dur-
ing construction.
CONCLUSIONS
Overall, the public health evaluation of remedial alternatives is
an iterative process that involves refining the design of specific
remedies. A risk-based approach for controlling releases usually
will demonstrate that one or two chemicals in the mixture are
responsible for most of the risk. These chemicals actually drive
the risk assessment and, therefore, drive the performance goals
for remedial alternatives. Once these chemicals are sufficiently
controlled, the risks from other chemicals in the mixture are like-
ly to be negligible in comparison.
When completed, the public health evaluation is submitted as
a chapter in the feasibility study report, available for review by
the public. Feasibility studies are required for both fund-financed
and enforcement-directed cleanups. Consequently, some form of
public health evaluation will be required at both types of sites.
SEMINARS 459
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Proper Design and Installation Techniques for
Groundwater Monitoring Wells
David M. Nielsen, C.P.G.
IEP, Inc.
Worthington, Ohio
INTRODUCTION
The installation of groundwater monitoring wells for the pur-
pose of detecting trace levels of both organic and inorganic con-
taminants in groundwater systems is a common practice in many
waste disposal and chemical spill scenarios. It is estimated that
tens of thousands of monitoring wells have been installed over the
past 5 yr, and that thousands more are installed annually. Many
of these wells are put in by consultants and contractors who are
not aware of the proper practices for monitoring well construc-
tion. As a result, many existing and currently installed monitor-
ing wells have critical design flaws or were and are installed util-
izing methods and/or materials that adversely affect the quality
of groundwater samples taken from them. Because the objective
of most groundwater monitoring programs is to obtain "repre-
sentative" groundwater samples, or samples that retain both the
physical and chemical properties of the groundwater being mon-
itored, proper groundwater monitoring well design and installa-
tion techniques to minimize the potential for sample chemical
alteration are imperative.
WELL PROBLEMS
Most groundwater monitoring well design and installation
problems can be traced to the mistaken belief that a "cookbook"
approach, which ignores site-specific hydrogeologic, geographical
and contaminant-related conditions, can be used in all situations.
The fact is that each monitoring well site is unique, thus re-
quiring a unique design for each monitoring well. The designer
must develop well design and installation specifications that take
into account anticipated site-specific conditions and are flexible
enough to accommodate alterations necessitated by unanticipated
conditions encountered during drilling.
Other groundwater monitoring well design and installation
problems stem from the fact that there are few professionals who
are adequately trained and experienced in proper monitoring well
construction practices and procedures. It must also be realized
that the analytical power of modern laboratories is now reaching
the parts-per-trillion detection level; the means of gaining access
to the subsurface to obtain groundwater samples for analysis is
crude by comparison. Still, most potential sources of sample
chemical alteration inherent in the monitoring well construction
process can be anticipated and controlled. Consultants and con-
tractors need a workable set of flexible guidelines for monitor-
ing well design and installation which is adaptable to a wide
variety of groundwater monitoring situations.
GUIDELINE DEVELOPMENT
The first step toward developing guidelines for monitoring well
design and installation is identifying the areas in which most prob-
lems arise. Among the most common monitoring well design
flaws and installation problems are the following:
• Use of inappropriate well casings or well screen materials (i.e.,
materials that have not been selected to be compatible with the
hydrogeologic environment, anticipated contaminants or the
requirements of the groundwater sampling program), resulting
in sample chemical alteration or failure of the well
• Use of non-standard well screen (i.e., field-slotted or drilled
casing), or use of incorrect screen slot sizing practices, result-
ing in sedimentation of the well and the acquisition of turbid
samples throughout the life of the monitoring well program
• Improper length and placement of the well screen, making the
acquisition of water level or water quality data from discrete
zones impossible
• Improper selection and placement of filter pack materials, re-
sulting in sedimentation of the well, plugging of the well screen,
groundwater sample chemical alteration and potential failure
of the well
• Improper selection and placement of annular seal materials,
resulting in alteration of sample chemical quality, plugging of
the filter pack and/or well screen or cross-contamination from
improperly sealed-off geologic units
• Inadequate surface protective measures, resulting in surface
water entering the well bore, alteration of sample chemical
quality or damage to/destruction of the well
• Improper or inadequate well development, resulting in acqui-
sition of sediment-laden samples, grout contamination of the
filter pack and subsequent alteration of sample chemical qual-
ity and reduced well yield.
Any one or a combination of these design/installation prob-
lems could result in a determination that a well or a series of
wells is unsuitable for obtaining representative groundwater sam-
ples. In many cases one or more of these errors necessitates the
abandonment of the improperly designed/installed well and the
installation of replacement wells, which can be very costly and
time-consuming. The use of proper groundwater monitoring well
design and installation practices is thus essential to ensure time-
and cost-efficient acquisition of representative groundwater
samples.
PROPER WELL DESIGN
Proper design and installation of groundwater monitoring wells
requires a thorough review of a variety of site-specific con-
ditions as well as an up-to-date knowledge of well design and
installation practices and procedures. Site-specific design con-
siderations include:
• The purpose or objective of the groundwater monitoring pro-
460 SEMINARS
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gram (i.e., water quality monitoring vs. water level monitoring)
• Surficial conditions, including topography, drainage, climate,
seasonal variations in climate and site access
• Known or anticipated hydrogeologic settings, including type
of geology (unconsolidated/consolidated), aquifer physical
characteristics (type of porosity, hydraulic conductivity), type
of aquifer (confined/unconfined), recharge/discharge con-
ditions and aquifer interrelationships
• Characteristics of known or anticipated contaminants (chem-
istry, density, viscosity, reactivity, concentration)
• Anthropogenic influences (i.e., man-induced changes in
hydraulic conditions)
• Any regulatory requirements that must be met
A unique set of site-specific design considerations exists for
each site and, in fact, for each well installation. This requires
that each well be designed as a unique structure.
To develop a knowledge of proper monitoring well design
practices, it is first necessary to understand the individual design
components of monitoring wells and how they combine to pro-
duce the final structure—the well itself. While it is not practical
to describe a "typical" monitoring well in which the design com-
ponents are fixed, it is possible to describe the individual design
components, which include the following:
• Well casings
• Well intakes (screens)
« Filter packs
• Annular seals
• Surface protective measures
These individual design components can be tailored and as-
sembled to suit the site-specific considerations described above.
PROPER WELL INSTALLATION
Proper installation of groundwater monitoring wells requires a
knowledge of state-of-the-art practices for well installation both
to avoid potential contamination of the well bore or well caused
by the well construction process itself and to permit easy access
to the subsurface for groundwater sampling and water level meas-
urement. Proper joining and placement techniques for well cas-
ing and screen, slot-sizing procedures for screens, placement and
sizing techniques for filter packs, placement procedures for annu-
lar seals, installation of surface protective measures and well
development techniques all must be used to ensure that a moni-
toring well will perform as intended.
APPENDIX SEMINAR OUTLINE
I. Factors Influencing Groundwater Monitoring Well Design
and Installation
A. Objectives of the Monitoring Program
B. Surficial Characteristics
C. Hydrogeologic Settings
D. Facility and Waste Characteristics
E. Anthropogenic Influences
F. Regulatory Requirements
II. Groundwater Monitoring Well Pre-Design/Installation
Considerations
A. Desired Method of Drilling
B. Anticipated Groundwater Sampling Method/Equip-
ment
C. Well and Aquifer Testing Requirements
D. Potential Use of Well Logging (Borehole Geophysical)
Tools
E. Method of Well Development Required
F. Method of Water Level Measurement Anticipated
III. Design Components of Groundwater Monitoring Wells
A. Well Casings
1. Purpose of the Casing
2. Effects of Casing Materials on Groundwater
Sample Integrity
3. Selection of Casing Sizes
4. Coupling Procedures for Joining Casing
B. Well Intakes (Screens)
1. Purpose of the Well Intake
2. Types of Well Intakes; Advantages/Disadvantages
of Each
3. Selection of Intake Slot Sizes
4. Discussion of Effect of Well Intake Length on
Groundwater Measurements
C. Filter Packs
1. Purpose of the Filter Pack
2. Types of Filter Packs; Where Each Type is Appro-
priate
3. Selection of Filter Pack Materials
D. Annular Seals
1. Purpose of the Annular Seal
2. Materials Used for Annular Seals
3. Methods of Emplacement of Annular Seals
4. Methods for Evaluating Annular Seal Integrity
E. Surface Protective Measures
1. Protection from Surface Water Runoff
2. Protection from Physical Damage and Vandalism
IV. Types of Monitoring Well Completions
A. Single Well Completions
1. Single Short Screened Interval
2. Single Long Screened Interval
3. Multiple Screened Intervals
B. Multiple Well Completions in a Single Borehole
V. Monitoring Well Development
A. Purpose of Well Development
B. Discussion of Methods Available; Advantages/Dis-
advantages of Each
C. Impact of Non-Development on Sample Integrity
VI. Groundwater Monitoring Well Post-Design/Installation
Considerations
A. Surveying Well Casings to a Common Datum
B. Identification of Wells
C. Mapping of Well Locations
D. Reporting Details of Monitoring Well Installation
E. Well Maintenance
SEMINARS 461
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Interrelationship Between Superfund and RCRA
Bill Hanson
Steven Smith
U.S. Environmental Protection Agency
Office of Emergencies and Remedial Response
Washington, D.C.
SUMMARY
For the past several years RCRA requirements have played an
important role in the analysis and selection of Superfund rem-
edies. Implementing RCRA consistent remedies is called for by
the policy on "CERCLA compliance with other Environmental
Statues" (published in the November 20, 1986, revision to the
National Contingency Plan). The CERCLA compliance policy
was largely embodied in the passage of the Superfund Amend-
ments and Reauthorization Act of 1986 (SARA). RCRA is the
most important environmental statute to analyze because it is the
most complex and because RCRA comprehensively manages haz-
ardous waste. The goals of this seminar will be to present an ana-
lytical framework for evaluating and incorporating RCRA re-
quirements into Superfund remedies.
Compliance with the other environmental statutes serves two
primary purposes. First, the requirements help in the selection of
remedies by either specifying a safe level in the environment or
directing the way in which hazardous waste should be treated or
managed. Secondly, following them helps to assure a reasonable
level of consistency between various Superfund sites.
The compliance provisions of SARA, Section 121 (d)(l), dis-
tinguishes between "applicable" and "relevant and appropriate"
requirements. "Applicable" requirements are those standards
that otherwise legally would be required. Requirements are "rele-
vant" if they would be applicable for jurisdictional restrictions.
Relevant requirements that are not appropriate to the Superfund
site may be modified or not used at all. Superfund remedies must
be consistent with relevant and appropriate requirements unless a
statutory waiver is used.
State's requirements are included under the new statute where
applicable or relevant and appropriate. (In the past, State
standards were considered and used unless a specific justification
was prepared in decision documents.)
RCRA requirements vary substantially depending upon the
scope and character of the CERCLA actions. There are at least 8
types of RCRA requirements that are important when develop-
ing and evaluating CERCLA response actions. Knowing when
these requirements are applicable or relevant and appropriate and
how they actually affect remedy configuration is very important
in meeting the statutory mandates.
Land Disposal Closure
Treatment Regulations
(e.g., incineration
regulations)
Land Ban
Design and Operating
Requirements
(e.g., double liners)
Location Standards
Groundwater Protection
Standards
Corrective Action
Regulations
(under development)
RCRA Regulations
Clean Closure
Potential Use
Determining extent of removal
Containing waste in place
When treatment is undertaken
Treatment requirements prior to
land disposal
New land disposal cell located in a
new area of the site
New land disposal cell located in a
new area of the site
Contaminated groundwater and
limitation on future releases
May cover many or most hazardous
waste scenarios
May become primary regulation
that Superfund looks to in the
compliance policy
Because of the greater problems at CERCLA sites, RCRA
requirements must be applied flexably to allow feasible actions
appropriate to the site circumstances. At many Superfund sites
there are no distinct areas of contamination and solutions to
problems that often apply across a site.
Which RCRA requirements may be applicable or relevant and
appropriate is site specific and action specific. For example, a
containment remedy where the waste is not treated will only need
to meet land disposal requirements. However, if the same waste
is treated and disposed in a new location on-site, the following re-
quirements may apply:
Treatment
Land Ban
Design and Operating Standards
Location Standards
Land Disposal Closure
Therefore, it is important to analyze potential RCRA require-
ments early in the RI/FS process so that remedies can be eval-
uated that meet or exceed minimum requirements.
462 SEMINARS
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Risk/Decision Analysis Module (RIDAM)
In Expert Systems
Chia Shun Shih
University of Texas, San Antonio
San Antonio, Texas
Hal Bernard
Hazardous Materials Control
Research Institute
Silver Spring, Maryland
ABSTRACT
An expert system, Hazardous Wastes and Management Expert
System (HAWAMAX), has been conceived and is being developed
at Hazardous Materials Control Research Institute. HAWAMAX
is designed to provide the "best" advice in a timely fashion to site
planners, managers or other decision-makers on how to improve
the site and its affected environment until it becomes "safe."
The HAWAMAX expert system is combined with the Risk/Deci-
sion Analysis Module (RIDAM) that incorporates all the field and
laboratory data and the socio-economic considerations. RIDAM
performs both risk assessment and decision analysis based on the
scientific inferences and decision-makers' judgemental inputs.
RIDAM, Risk/Decision Analyzing Module, is capable of identi-
fying, classifying, simulating, estimating and comparing the risks
of all potential actions and assessing the acceptability of the overall
costs imposed on both voluntary workers and involuntary public.
RIDAM can also generate multiple management/control ap-
proaches in order to eliminate or minimize some of the risks and
conduct a systematic analysis of all potential consequences resulting
from each of the managerial or control courses of action. In addi-
tion, a comprehensive assessment and ranking of choiced courses
of activities will be developed for ultimate judgement by the
decision-makers together with sensitivity analysis.
HAWAMAX
The HAWAMAX expert system is a computer analysis package
with the capability of performing at the level of human experts
in specific fields. It is possible to build expert systems that perform
at remarkable levels. Though several methods exist for designing
expert systems, rule-based systems have emerged as the popular
architecture. Deriving or extracting knowledge from relatively easily
understand facts and rules, rule-based systems offer surprising
power and versatility. HAWAMAX is a rule-based expert system
that operates RIDAM the way a human expert would to determine
three different sets of decisions: (1) risk estimation and assessment,
(2) risk managerial actions and (3) consequences evaluation. The
preferential ranking activities will be developed together with the
description of consequences for the final most "satisfied" choice
by decision-makers.
As shown in Figure 1, RIDAM is the "Centerpiece" module
inside the HAWAMAX system which consists of four other
modules:
• Knowledge-base of Rules and Facts Module
• Inference Module
• Environmental and Site Description Module
• Data Base Module
Figure 1
The Hazardous Wastes Management Expert
(HAWAMAX) Components
The Knowledge-base of Rules and Facts Module contains sets
of planning, designing, engineering, monitoring-, and regulating
rules, standards, considerations, functions and specifications in
descriptive formats. The Inference Module extracts the pertinent
rules and facts and determines alternative feasible plans and designs
subject to the identified specifications. It also organizes the out-
put data into files according to hypothesized environmental and
site characteristics. These are then fed into the Data Base Module
to create and enhance the bases of inference. The Inference Module
is designed to generate a series of output files in stochastic nature
through an array of simulation models developed by human
experts.
The Environmental and Site Description Module compiles all
functional and coherent data and descriptive relations defining site
and environmental consideration to assist the decision-makers'
understanding of the physical, chemical, geological and biological
interactions among sites, pollutants, potential hazards, pathways,
short-term and long-term effects, socioeconomic impacts and
special legal and regulatory requirements.
SOFTWARE
The software requirements of HAWAMAX are primarily for
the inference Module (IM) and Risk/Decision Analysis Module
(RIDAM). The Inference Module (IM) is written in LISP, while
RIDAM is being developed in Fortran. Both will be developed on
a PC under respectively common LISP and Fortran 80.
SEMINARS 463
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RID AM
RIDAM is the final driver segment of the HAWAMAX system
and will begin with the risk definition through the final evalua-
tion of alternative managerial approaches. As shown in Figure 2,
the following subcomponents are included:
Risk Identification Processor
Risk Information Processor
Alternative Managerial Course of Actions Generator
Risk Prevention and Containment Controller
Risk Acceptability Evaluator
Costs and Benefits Estimation
Decisions Attributes Processor
Stochastic Events Assessor
Intangible Factors Evaluator
Utility Function Module
Decision Analysis Processor
Sensitivity Analysis Generator
Output and Display Processor
In this seminar, the logical and analytical backgrounds of
RIDAM will be presented in detail. Special examples illustrating
the applications of RIDAM and its interactions with other com-
ponents as shown in Figure 2 will be discussed.
Multlattribute Decision Anatyrif
This evaluation process is accomplished by the following
analytical procedures:
• Systematically organize the hazardous waste management prob-
lems into a sequential decision-making problem
• Develop an appropriate multiattributc utility function for the
consequence evaluation while incorporating risk as one attribute
• Identify and estimate all probability values for all chance events
• Estimate the relative weight values for each of the attributes
• Compute the expected utility values based on utility functions
and probability values for all other events
• Compute the courses of actions based on expected utility values
Illustrative examples will be presented to demonstrate the flex-
ibility and versatility of RIDAM.
from OBM from IM
From DBM
To OBH
From in
To DBM <
From OBM
Risk Identification
Processor
Risk Quant I float Ion
Processor
Alternative
Managerial
Course of Actions
Generator
Risk Acceptabl I Ity
Evaluator
To i" <-
from IM
To OBM <-
J,
Cost/Benefits
Estimator
I—I
Decision Attributes
Processor
Stochastic Events
Assessor
Sens!tIvlty Analys is
Generator
Outputs/Display Processor
Utility Function
Modeller
Decision Analysis
Processor
From DBM
Figure 2
Risk/Decision Analysis Module (RIDAM)
464 SEMINARS
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Geophysical Techniques for Sensing Buried Wastes
And Waste Migration: An Update
Richard C. Benson, C.P.G.
Lynn B. Yuhr
Technos, Inc.
Miami, Florida
INTRODUCTION
Traditional approaches to subsurface field investigations at
hazardous waste sites often have been inadequate because many
investigations have commonly relied upon point measurements.
When a monitoring well is installed to characterize the level of
contaminants, there is usually utmost confidence in the results of
the analysis to the mg/1 concentration level or less. Yet, the source
of the sample with regard to the representativeness of the moni-
tor well's location and the screen depth and interval is almost
totally ignored. As a result, samples will not necessarily be repre-
sentative of site conditions.
It is difficult and probably impossible to characterize the
natural conditions with 100"% accuracy. However, we need to
achieve a reasonable level of accuracy in subsurface evaluation
or all the modeling, engineering and decision-making will often be
unacceptably inaccurate. The need for complementary ap-
proaches to subsurface investigation has emerged because of these
problems.
Over the past few years, numerous new, modified and com-
binations of subsurface investigation techniques have evolved.
The application of geophysical techniques is one of those emer-
ging approaches which provides a level of insight necessary to
improve upon the accuracy of subsurface investigation.
A report entitled Geophysical Techniques for Sensing Buried
Wastes and Waste Migration was written in 1983 to meet the
U.S. EPA's initial needs in the area of geophysics. This technol-
ogy transfer document has been published and distributed by
NWWA and NTIS. This paper is a review and update which ex-
pands upon this publication.
Airborne, surface and downhole geophysics may be applied to
evaluate hydrogeologic conditions and in some cases even map
contaminants. The selection of the method or methods depends
on the size of the site and the type and amount of data required.
There are many geophysical methods that may be used: (1) those
which provide geologic and structural data, such as the seismic
and gravity methods, and (2) those which also can detect and map
contaminants, such as the electrical methods. Since electrical re-
sistivities of geologic formations are highly dependent upon the
amount of dissolved solids in the groundwater, both resistivity
and electromagnetic geophysical methods are ideally suited to
map inorganic contaminants which have high specific conduc-
tance.
This work focuses on the surface and downhole geophysical
methods. A number of surface geophysical methods can be em-
ployed, including:
• Ground Penetrating Radar
• Electromagnetics
Resistivity
Magnetics
Seismic Refraction
Seismic Reflection
Microgravity
Metal Detection
As depth increases, the accuracy and the detail obtained by sur-
face geophysics decreases. In contrast, the downhole geophysical
logging methods not only provide considerable detail, but also
maintain the detail independent of depth. If existing wells are
available, measurements of lithology or hydrogeologic character-
istics such as density and porosity as well as some contaminant
measurements can be obtained at little cost. The downhole meth-
ods to be considered include:
Single Point Resistance
Natural Gamma
Induction (electrical conductivity/resistivity)
Neutron-Neutron (moisture/porosity)
Television
Spontaneous Potential (SP)
Caliper
Resistivity
Gamma-Gamma (density)
Both the surface and downhole geophysical methods measure
bulk physical and electrical properties of the soil and rock and
allow a high density of measurements to be taken for a relatively
small cost. By increasing the spatial density of sampling, a better
characterization of site conditions can be made prior to drilling
and sampling, therefore optimizing the quantitative analysis ob-
tained. Knowing how to select an optimum field approach is of
critical importance to a successful field investigation. The objec-
tives of this paper are to introduce some of the commonly used
geophysical methods and their applications and provide aids to
help select the right methodology to ensure reasonably correct de-
cisions to improve the accuracy of subsurface information.
APPLICATION OF GEOPHYSICAL METHODS
There are three major areas for the application of geophysical
methods at hazardous waste sites: (1) assessing natural con-
ditions, (2) assessing contaminant migration and cultural factors
which may impact them and (3) delineating buried wastes.
Assessing Natural Conditions
One of the most important tasks of any site investigation in-
volves evaluating the site's natural setting. In many cases, map-
ping natural geologic conditions with geophysical techniques pro-
vides an insight not obtained with a limited boring program.
Characterization of the lateral and vertical extent as well as any
SEMINARS 465
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discontinuities of sand and clay lenses, fracture zones, buried
relic stream channels and so forth will significantly improve the
accuracy of hazardous waste site assessment. In addition to char-
acterizing the site geology, an evaluation of hydrologic proper-
ties sometimes can be made.
Assessing Contaminant Migration
The mapping of contaminant plumes often can be easily
accomplished using electrical methods. Because inorganics are
often more electrically conductive than groundwater, their extent
can be mapped both laterally and vertically using electrical tech-
niques. This mapping provides a means of directly character-
izing the extent of the contaminant in situ and provides an indica-
tion of any anomalies. This assessment can be a vital part in mod-
eling groundwater flow. Furthermore, these methods can be used
for time series measurements of plume dynamics. Although
organics are usually non-conductive, they are commonly asso-
ciated with inorganics. If a mixture of organics and inorganics
exists, the organics then can be mapped using electrical methods.
In cases where pure organics such as TCE, CTET, gasoline
and diesel fuel, etc., exist, geophysics often can be used to define
the permeable pathways or top of rock along which the contam-
inants may migrate. By mapping contaminant plumes in this man-
ner, locations for representative monitor wells can accurately be
made, and cleanup costs can be minimized. Cultural features
such as buried utilities and tanks which impact flow also can be
identified and assessed.
Assessing Burled Wastes
Geophysics can be used to locate and map the extent of buried
waste including:
• Location and boundaries of landfills
• Location of burial trenches
• Location of buried 55-gal drums
• Location of buried tanks and pipes
• Location of buried utility lines
SFLECTING AN OPTIMUM METHODOLOGY
In developing general guidelines for selecting methodologies, it
must be stressed that no single approach or technique (geophysi-
cal or otherwise) is a panacea for any site investigation. This
paper outlines the advantages and disadvantages of a number of
the geophysical methods and provides rules of thumb for their
application. A number of examples are given along with approx-
imate costs. The key starting point of any site investigation is a
clearly identified purpose and scope of work; only then can the
technical and cost trade-offs be accurately made.
466 SEMINARS
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The Role of the Agency for Toxic Substances
And Disease Registry in Superfund Response
Robert C. Williams, P.E.
William Cibulas, Jr., Ph.D.
C. Harold Emmett, P.E.
Jeffrey A. Lybarger, M.D.
Agency for Toxic Substances and Disease Registry
Office of Health Assessment
Atlanta, Georgia
ABSTRACT
Improper disposal of chemicals in the United States has pro-
duced a large number of uncontrolled hazardous waste sites.
Potentially harmful materials from these sites have contaminated
groundwater, surface water, soils and air. In response to the
threat these sites pose to health and to the environment, Con-
gress enacted CERCLA in 1980. The Agency for Toxic Sub-
stances and Disease Registry (ATSDR) was one result of this law.
Congress charged ATSDR with specific tasks designed to improve
the understanding of the relationships between toxic waste ex-
posure and illness. ATSDR's response to the Congressional
charge is described in this manuscript.
ATSDR works closely with local, state and Federal agencies
to eliminate or reduce illness, disability and death resulting from
human exposure to toxic substances at spills and waste disposal
sites. ATSDR's administrative office supervises two program
offices: the Office of External Affairs (OEA) and the Office of
Health Assessment (OHA). OEA is responsible for activities out-
side of the Agency, such as managing interagency agreements
and coordinating the creation of disease/exposure registries.
OHA is responsible for conducting most of the CERCLA-
mandated tasks. It has a technical support staff whose primary
areas of expertise are health assessment reviews and exposure
studies.
ATSDR is active in many health-related areas of America's
hazardous waste problem. Today, ATSDR's primary emphasis is
on environmental public health assessment which involves a
multidisciplinary, preliminary review of all available data on a
particular hazardous waste site. The purpose of this review is to
assess the nature and magnitude of any threat to human health.
In such health assessments, environmental pathways and ex-
posure pathways are carefully studied and the estimated poten-
tial risk to human health is determined. These assessments help
health personnel decide whether full-scale health or epidemiolog-
ical studies are warranted and whether medical evaluations of
exposed populations should be undertaken. The U.S. EPA con-
siders health assessments in evaluating the need for remedial
activities.
ATSDR's responsibilities, how the Agency is organized and the
role it plays in Superfund response are described in this manu-
script. The health assessment review process is discussed in detail
and the complexities surrounding the evaluation of environmen-
tal and exposure pathways are examined. Uncontrolled hazardous
waste sites are a major public health problem in the United States;
they also are politically significant. Learning more about ATSDR
and the health assessment process should prove valuable to any-
•This paper is a summary of a seminar manuscript by the same title. The areas dis-
cussed in this summary are covered in significantly greater detail by the full manu-
script.
one concerned with hazardous waste.
INTRODUCTION
In 1980, Congress passed CERCLA which contains a provision
to establish the Agency for Toxic Substances and Disease Regis-
try (ATSDR). This new agency was created within the Public
Health Service to carry out the health-related responsibilities of
CERCLA. Congress charged ATSDR with specific tasks designed
to increase what is known about the relationships between toxic
waste exposure and illness.
The original concept of ATSDR as defined by these tasks has
not changed, but perhaps the Agency's charge has become more
specific. ATSDR works closely with local, state and other Fed-
eral agencies to reduce or eliminate illness, disability and death
resulting from the exposure of the public (and of workers) to toxic
substances at spill and waste disposal sites. Beyond the original
tasks, ATSDR's mission has expanded to include the perfor-
mance of health assessments at Superfund sites. Indeed,
ATSDR's primary activity is the environmental public health
assessment.
ORGANIZATIONAL STRUCTURE
Before proceeding with a discussion of health assessments,
some knowledge of the organizational structure of ATSDR is
necessary. The Agency is directed by an Administrator who re-
ports to the Assistant Secretary for Health. Day-to-day opera-
tional control is provided 'by the Associate Administrator, who
manages the two program offices: (1) External Affairs and (2)
Health Assessment.
The Office of External Affairs is responsible for activities out-
side of the Agency, such as managing interagency agreements
and coordinating the development of exposure/disease regis-
tries. The Office of Health Assessment contains most of the tech-
nical support staff, who are responsible for responding to emer-
gency requests from the field, initiating protocols and training
for state capacity building and performing multidisciplinary re-
views of uncontrolled hazardous waste sites or any other man-
dated health-related activity relevant to toxic wastes.
HEALTH ASSESSMENTS
Health assessments are multidisciplinary, preliminary reviews
of all available data relevant to the site. The reviews are carried
out to evaluate the nature and magnitude of any threat to human
health from the site. They involve a thorough assessment of en-
vironmental pathways and exposure pathways and ultimately end
with some determination of the potential risk to human health
posed by the site in question. The purpose of such assessments is
to help determine whether full-scale health or epidemiological
SEMINARS 467
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studies are warranted and whether medical evaluations of ex-
posed populations should be undertaken. Health assessments
also assist the U.S. EPA in evaluating planned remedial activities
for a site.
Environmental Pathways Assessment
ATSDR assessment of environmental impacts begins with a
selection of the contaminants of concern. Concurrent with the
selection of indicator chemicals, ATSDR engineers review release
mechanisms and the media to which releases might occur. Then
the staff starts to evaluate the effects of potential transport or
transformation mechanisms. The method ATSDR uses to screen
each medium involves both qualitative and quantitative proced-
ures.
Environmental fate mechanisms that potentially may be sig-
nificant at the site in question are selected by asking simple, gen-
eric questions. Quantitative assessment follows. Computer-based
models can be used to supplement "best engineering judgment"
on decisions concerning in-depth analysis of integrated release
sources, environmental transport media and the environmental
fate of indicator chemicals.
Provided sufficient data are available, ATSDR's environmen-
tal pathways assessment will conclude with considerable informa-
tion on the chemicals of concern, their fate and the potential
routes of human exposure. This information is analyzed by epi-
demiologists and lexicologists to generate a public health evalua-
tion of the site. These evaluations are known as human exposure
assessments.
Assessment of Human Exposure Pathways
Once the site contaminants and environmental pathways data
sets are complete, human receptors and exposure pathways can
be determined. To present a hazard to humans, the contami-
nants must get from the environment to those humans. The major
routes by which humans can be exposed to environmental con-
taminants at hazardous waste sites include ingestion, inhalation
and dermal absorption. The significance of each pathway de-
pends on site-specific information that is collected and incorpo-
rated into a risk assessment.
Estimating the dosage to which humans may be exposed is im-
portant in determining the significance of the exposure pathway.
Route-specific dosages to a contaminant are calculated and com-
pared with existing standards for human exposure. Often,
assumptions must be made when scientific data are unavailable.
These assumptions may include considering the "worst case,"
even if it provides an extremely conservative result that is prob-
ably unrealistic.
Characteristics of the site also help determine the significance
of the exposure pathways. Physical access to the site and the like-
lihood of human contact with the contaminated matrix cannot
be overlooked when assessing risk. Demographics and cultural
characteristics may be important in determining which popula-
tion segments may be exposed to the contaminants. The exposure
potential may be influenced by proximity to the site, daily activi-
ties and lifestyle. ATSDR scientists consider all of these factors
and more when they characterize the risk to the public health for
communities adjacent to hazardous waste sites.
In most cases, the interpretation of site data follows a logical
forward sequence in the evaluation of the potential for human ex-
posure and adverse health effects. At times, however, a cluster or
increase in adverse health conditions is recognized in a particular
area. ATSDR then proceeds to determine if these health effects
can be causally linked with exposure to contaminants from a toxic
waste site. If the Agency concludes that people potentially may
have been exposed, an exposure study may be performed to con-
tribute to the overall utility of any future risk-management de-
cisions.
EXPOSURE STUDIES
ASTDR scientists conduct exposure studies of communities
potentially exposed to hazardous waste contaminants. Results of
these studies are used to determine if the presence of the contam-
inant has resulted in either an exposure to the compound (that
is, elevated body burden relative to a control population) or an
adverse health effect. All available site information and the
ATSDR health assessment document are used to identify the
potentially exposed population. Questionnaires, developed and
administered by the Agency's scientists, are designed to define
groups at highest risk of exposure to site contaminants and to
determine if there appears to be an associated increased incidence
of reported health complaints.
Biologic testing of persons potentially exposed to the contam-
inants then may be done to determine if they have elevated body
burdens and to better understand the relationship between media
concentration, bioavailability, uptake, exposure and health
effects.
At present, ATSDR is conducting exposure assessments in sev-
eral communities. Besides addressing a community's health con-
cerns, data generated from these assessments can provide key
information that will better define exposure assumptions used
for quantitative risk assessments.
EMERGENCY RESPONSE HEALTH
ASSESSMENTS
The sudden and uncontrolled release of hazardous materials
requires the rapid and systematic use of the health assessment
process to prevent local residents from being exposed to haz-
ardous materials or at least to reduce the toxic effects of such ex-
posures. The health assessment process previously described for
hazardous waste sites is the same process by which the emergency
response is rendered. However, the emergency response requires
making and implementing public health decisions with little or
no data. Thus, some forethought is necessary if health personnel
are to respond adequately.
Protecting public health in an emergency situation is based
on two principles. First, the sudden release of hazardous ma-
terials represents a new exposure. It is a new health burden that
was not present even days earlier. With rapid action, an exposure
may be prevented completely, not just limited in duration.
Second, only the immediate exposure needs to be addressed
immediately. Control decisions should be limited to critical ex-
posure routes. Those decisions not immediately necessary should
be deferred to a time when the decision-making process can be
more deliberate, less stressed and less prone to error.
On the basis of these principles, the emergency response
health assessment identifies likely migration pathways, potential
human exposure pathways, populations at risk and actions re-
quired to prevent human exposure to sudden toxic releases.
468 SEMINARS
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Toward an Effective Strategy
For Dealing with Superfund
Peter H. Haller
Karr, Tuttle, Koch, Campbell,
Mawer, Morrow & Sax
Seattle, Washington
INTRODUCTION
The impact of CERCLA and its state counterparts underscores
the fact that lawmakers have implicitly promised a substantial
amount of risk reduction posed by hazardous substances to society.
The promises embodied in these laws, together with the prospects
for liability which these laws present, have and will continue to
have a profound effect upon the decision-making of domestic cor-
porations, foreign corporations and other parties who may be
affected by the laws' liability provisions.
Liability under Superfund may be either direct (as in the case
of potentially responsible parties) or indirect (as in the case of in-
surance companies, investment institutions or successor corpora-
tions). The prospects for liability to this second class of parties
may appear to be much less obvious because they may never have
dealt with the generation or disposal of hazardous substances.
Because Superfund and its state counterparts present such great
potential for liability, often of an unquantifiable nature in terms
of time and amount, it is becoming imperative that all parties who
may be affected by these laws realize that the time has come to
devise a long-term strategy for dealing with them. Such a strategy,
based upon the author's representation of potentially responsible
parties, banking institutions and insurance companies, is sum-
marized below.
STRATEGY ELEMENTS IN COMMON TO ALL PARTIES
Two common elements of any overall strategy, whether it be
one employed by a potentially responsible party (PRP) or another
party who may become indirectly affected by Superfund type
legislation, are discussed first.
First, all potentially affected parties must be knowledgeable
about the requirements and provisions of the laws. Although the
finer points of the law and case decisions thereunder may be within
the province of legal counsel, there is no excuse for parties not
taking the time to be thoroughly briefed by counsel or to attend
seminars or training sessions where the laws and regulations are
discussed. (Herein will be discussed in brief fashion several of the
key liability provisions under Superfund as amended in 1986.)
Second, all parties should appreciate that the implementation
of Superfund ultimately involves agency decision-making which
has at least three key components: the legal component, the scien-
tific or engineering component and the public policy /political
component. Parties should hever fail to underestimate the extent
of the last component, which may be the most important in
finalizing decisions regarding cleanup.
STRATEGY FOR THE POTENTIALLY
RESPONSIBLE PARTY
The author's experience at a half dozen Superfund sites in several
western states strongly suggests that PRPs will want to seriously
consider adopting a strategy that involves the following elements.
First and early in the process (even before a site has been
designated for inclusion on the NPL), the farsighted party should
form a team including managerial personnel, technical/engineering
personnel, legal personnel and, perhaps, public relations personnel.
This team should be given the responsibility, as well as the author-
ity, to study a site and, if necessary, implement remedial measures
even before a site becomes designated on the NPL.
Second, as soon as notification is received from agency officials
concerning PRP status, a party must inform its insurers of the event
and attempt to obtain their cooperation in further dealing with
events as they unfold.
Third, when and if a property becomes listed on the NPL, a far-
sighted party should attempt to become involved in the develop-
ment of information concerning that site and should seriously
consider undertaking the RI/FS for that site, even if it requires
entering into an-enforceable consent agreement with a state or
federal agency. The ability to generate information about a site
and to use one's experts to argue in favor of conclusions that can
be drawn about that information forms one of the few oppor-
tunities to "go on the offensive" under Superfund. Unless a party
has a truly minimal involvement with a site, an active role in
decision-making at the site should be considered.
Finally, experience suggests that PRP-conducted cleanup can
probably be done at lower costs than when undertaken by the
government. This, in turn, suggests that a party should give serious
consideration to participating in the ultimate remedy.
STRATEGY FOR THE INDIRECTLY LIABLE PARTIES
Parties such as insurance companies, banking institutions and
successor corporate owners must realize that Superfund type laws
can reach out at any time and embrace them in a web of financial
exposure even though they have not been directly involved in the
generation, transportation or disposal of hazardous substances.
First, these parties should realize that court decisions are pointing
in the direction of holding them responsible as "operators" of
Superfund sites where their involvement in day to day manage-
ment has been pervasive. Furthermore, these parties should be
aware of the substantial hurdles for escaping landowner liability
at a Superfund site that are contained in the 1986 amendments.
Second, such parties should put themselves in a position to
identify sites that are to be considered "suspect" or businesses that
may be considered suspect because of the types of materials they
deal with. For example, these parties will want to maintain a current
copy of the NPL of sites, to obtain from the U.S. EPA a list of
sites on a state-specific basis which have been surveyed by the U.S.
EPA's FIT for Superfund consideration and/or to obtain a list
of parties who have notified the agency that they have generated
sufficiently reportable quantities of hazardous substances pursuant
to the reporting requirements of Superfund. Such listings are
publicly available. At a minimum, these listings can form the basis
for intelligent inquiry of an industry on the list by someone who
might wish to do business with them.
Third, "indirectly responsible parties" should seriously consider
SEMINARS 469
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site investigations by qualified consultants before acquisition is CONCLUSION
made of any "suspect" site, before a loan is granted to a business The prospects for liability under Superfund and its state counter-
operating such a site or before a mortgage interest is taken on such parts can stagger the imagination. Nevertheless, there are measures
a site. By obtaining this information, these parties will be in a better which can be employed to avoid, minimize or, if nothing else,
position to make decisions based on an intelligent analysis of the manage the problem. This presentation has discussed some of these
risk involved. measures.
470 SEMINAR^
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Selecting PPE — "I Haven't a Thing to Wear
Richard M. Ronk
National Institute for Occupational Safety and Health
Division of Safety Research
Morgantown, West Virginia
The use and transport of hazardous materials is ever increas-
ing, and more and more formerly "benign" substances are being
included in this group. Yet recent Congressional studies estimate
that, at best, only about 25% of haz-mat responders are ade-
quately trained. One glaring inadequacy in their training is in their
inability to protect themselves from the effects of a hazardous
materials incident or, in fact, to protect themselves from their
protective equipment! One very knowledgeable haz-mat re-
sponder has written, "Protective Ensembles May Be Potentially
More Hazardous Than the Incident."
But personal protective equipment is the only practical protec-
tive measure available if we are to continue to respond to spills
and releases.
Selection of safe and effective chemical protective clothing and
respirators is a complex task, made ever more difficult by the
exigencies of a spill or accidental release. Proper selection of
protective equipment requires balancing the often conflicting de-
mands of numerous factors. Among these factors are the environ-
ment to which the worker is exposed, the operating characteristics
of available equipment, the task to be performed and the limita-
tions imposed by the human body.
Protective equipment severely limits the performance of a task
and imposes significant additional stress on the wearer. Protec-
tive equipment, in turn, is limited by the environment, the task,
the wearer, and its own design and construction. The perfect en-
semble does not, and cannot, exist. Every use requires compro-
mises and tradeoffs such as duration for weight, effectiveness for
thermal stress or protection for cost.
In order to assist the haz-mat responder in making these de-
cisions, NIOSH has developed a selection algorithm published in
"Personal Protective Equipment for Hazardous Materials Inci-
dents: A Selection Guide," (NIOSH 84-114). This algorithm also
is available as a floppy disc for IBM compatible microcomputers
(PCs).
A brief study of each of the major classifications of selection
factors will serve to illustrate the need for some type of struc-
tured aid to decision-making.
ENVIRONMENTAL FACTORS
The Chemical Exposure
• Materials or classes of materials
• State(s)
• Dispersal.
• Quantity or concentration
• Flammability—explosivity
• Radioactivity
• Sensitivity to shock
• Toxicity and "safe limits"
• Route of entry
• Vapor pressure
The Site Conditions
Slope
Terrain
Temperature
Relative humidity
Radiant heating
Oxygen concentration
Available Equipment
• Chemical resistance
Permeation
Penetration
Degradation
• Field protection factors
• Service life
• Weight
• Encumbrance
Task
• Special hazard such as fire fighting
• Required workrate
• Required mobility
• Distance to exposure
Human
• Weight
• Conditioning
Laboratory and field tests as well as practical experience in the
use of this algorithm have demonstrated usefulness as an aid to
decision-making. No algorithm or computer program should be
expected to replace the professional judgment required of a haz-
mat responder. This algorithm can assist in logically and concise-
ly requiring consideration of, and decisions on, the key selection
factors and thereby lead to more effective selection and use of
protective equipment.
(Copies of the program are available as
author.)
'PREMENU" from the
SEMINARS 471
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Health, Safety and Training Requirements
For Hazardous Waste Site Workers
Martin S. Mathamel
Camp Dresser & McKee Inc.
Annandale, Virginia
INTRODUCTION
Federal regulations and guidelines including recent "Right-to-
Know" legislation have emphasized the need to develop and
implement comprehensive health, safety and training programs
for hazardous waste site (HWS) workers. Although some of these
regulations and guidelines are not specifically aimed at HWS
workers, they represent current regulatory intent. Due to im-
plicit liabilities, Firms involved in HWS operations must be cog-
nizant of regulatory intent; they also must have the foresight to
have state-of-the-art in terms of health, safety, and training pro-
grams. This is particularly true in light of OSHA's announced
intent to audit Superfund sites for compliance with health and
safety regulations via a National Special Emphasis Program,
along with statistics that show that the accident/injury rate for
HWS workers is 2.5 times greater than for manufacturing in-
dustry workers. Also, the U.S. EPA's current concerns regard-
ing "Community Right-To-Know" for residents who live in the
proximity of HWS operations further underscores the need for
health and safety trained field workers.
This seminar presents an overview of a comprehensive health,
safety and training program aimed at HWS field workers.
APPLICABLE REGULATIONS AND
GUIDELINES
OSHA Safety and Health Standards (29 CFR 1910 and 29
CFR 1910/1910) are the major, legally binding standards that
apply to HWS workers. Noncompliance with these regulations
can result in fines and citations. Portions of the National Oil and
Hazardous Substances Pollution Contingency Plan (40 CFR
300) also apply. These documents, however, do not provide ade-
quate guidance in terms of establishing an effective health, safety
and training program. The best guidance available is from two
documents: "Occupational Safety and Health Guidance Manual
for Hazardous Waste Site Activities" (N1OSH/OSHA/USCG/
EPA, Oct. 1985) and Standard Operating Safety Guidelines
(U.S. EPA, Nov. 1984)_
HEALTH, SAFETY AND TRAINING
PROGRAM MANAGEMENT STRUCTURE
An important concept in understanding the program's man-
agement structure is that safety management is similar to QA/QC
management; it must be distinctly separate from site operations
management. The program Health and Safety Manager (HSM)
must have absolute authority to halt site operations and to pro-
hibit workers from participating in site activities because of safety
deficiencies. The HSM should be certified, e.g., CIH or CSP, be
experienced in hazardous waste activities, be required to report
directly to a senior officer of the firm and be on 24-hr call.
Each site should have a Site Health and Safety Coordinator
(SHSC) who reports to the HSM and has authority to halt site
operations until the HSM can resolve the conflict. Large pro-
grams may require a Regional Health and Safety Supervisor
(RHSS) with intermediate authority between the HSM and
SHSC. The HSM and RHSS must make frequent site audits and
train workers on a regular basis.
MEDICAL AND EXPOSURE INJURY
SURVEILLANCE PROGRAM
All HWS workers must be certified, by a licensed physician, to
be medically qualified to perform hazardous waste site activities
and to use respiratory protective devices to perform hazardous
waste site activities. This involves medical examinations on an an-
nual basis, following an exposure or injury, after continuous
field assignment of 6 months, upon employment termination or
upon the request of the worker, the HSM or the physician. Exam-
ination protocols vary (some protocols appear in the publications
mentioned above), but OSHA regulations require that the physi-
cian modify the protocol in order to certify individual workers.
Current medical opinion is that HWS activities may pose a risk
of harm to the unborn children of HWS workers unless protective
measures are taken. This protection involves restricting field par-
ticipation of workers who are pregnant or actively trying to con-
ceive. Worker counseling is required to make this aspect of the
medical program effective, as it must be based on mutual trust,
understanding, sharing of information and cooperation between
the employee and employer.
All injuries and exposures that occur on a waste site, no mat-
ter how small or seemingly insignificant, must be reported immed-
iately to the HSM. Exposures are difficult to quantify, but all
potential exposures should at least be discussed with the HSM.
Workers should be required to submit, on a monthly basis, an
exposure report summarizing the sites that they have worked on,
any exposures or injuries and, most importantly, any observa-
tions or occurrences that indicate health and safety violations or
deficiencies. The report is confidential and allows the HSM to
monitor program effectiveness.
RESPIRATOR, PROTECTIVE CLOTHING
AND MONITORING PROGRAM
Workers must be provided adequate respirators and other types
of protective clothing. Respirator fit tests must be conducted by
certified (by the HSM) respirator fit examiners on an annual basis
after facial/dental surgery or after 10 Ib weight gain/loss. Protec-
tive clothing must be adequate to protect against the anticipated
hazards but not too restrictive or excessive as to present a hazard
to workers. Safety monitoring (e.g., air, and heat/cold stress)
472 SEMINARS
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normally is conducted by the SHSC, with frequent reports to the
RHSS or HSM. The HSM normally approves site respiratory
protective clothing and monitoring equipment requirements as
part of the site safety plan.
BASIC HEALTH AND SAFETY
TRAINING COURSE
No worker (including subcontractors) can be allowed to partici-
pate in HWS activities until he/she has been trained to conduct
those activities commensurate with the degree of anticipated haz-
ards. This preparation normally involves providing basic health
and safety training, as well as on-the-job training, periodic re-
fresher training, site specific training and first aid/CPR training.
CERCLA requires that workers receive a minimum of 5 days (40
hours) of preassignment basic training, followed by a minimum
of 3 days of on-the-job training under the supervision of a
trained, experienced supervisor. Experience has shown that this
initial training needs to be supplemented with first aid/CPR
training and followed by continued on-the-job, refresher, and site
specific training. Supervisors require the basic course and at least
1 day (8 hours) of specialized hazardous waste site management
training.
• Levels of Protection. The U.S. EPA has adopted a compre-
hensive system for specifying what type of protective gear is to
be worn based on four levels of protection: A, B, C and D. The
equipment that is used for each level and selection criteria are
discussed.
• Hazard Recognition and Evaluation. Workers are exposed to
physical, chemical and biological hazards. Regulations man-
date that personnel be able to recognize these hazards. Instruc-
tion dwells on recognition by stressing thinking before reacting;
common sense is the key. The bottom line is if personnel feel
unsafe, the task is to be delayed until a sound approach has
been devised. Personnel are taught to be rational in their ap-
proach to hazards and to know when to seek expert advice.
Merely defining the hazard is not sufficient. The significance of
the hazard in field operations is of importance.
• Personnel Exposure Standards/Guidelines. Exposure
standards/guidelines for toxic, explosive, radiation, noise and
heat/cold stress hazards are discussed. The implications of the
guidelines and the fact that many are recommendations based
on assigning safety factors to the expected reaction of "nor-
mal" humans under "normal" conditions should be stressed.
Field conditions may drastically alter the guidelines. The key is
educating workers to recognize when they need an expert to
develop new guidelines and when they can rely upon preestab-
lished ones.
• Sources of Information/Hazard Recognition (Problem).
Workers need health and safety data to assess hazards. An in-
troduction detailing the advantages and limitations of various
information sources is presented, followed by a hazard recog-
nition problem in which workers develop hazard fact sheets.
• Monitoring Instruments (Workshop). Workers use monitor-
ing equipment to characterize sites, determine level of protec-
tion and estimate community impact. Instruction in the actual
use of available equipment is provided. Standard operating
procedures, calibration, maintenance, data reporting and in-
terpretation, and "action" levels based on exposure guide-
lines are stressed.
• Heat/Cold Stress. Heat/cold stress is one of the most severe
hazards that workers face. Workers are instructed in how to
recognize, manage and monitor heat/cold stress.
• Protective Clothing. The basic gear provided to workers is
discussed and demonstrated, including limitations, mainten-
ance, storage, disposal and guidelines for determining when
the clothing is no longer usable.
• Respiratory Protection (Introduction and Use) (Exercise).
Workers are instructed on the use, cleaning, maintenance, stor-
age and troubleshooting of specific types of respiratory protec-
tive gear. A qualitative fit test is performed, and the theory of
respiratory protection, selection criteria and physiological/
psychological restrictions is discussed. Workers participate in
exercises that simulate field conditions.
• Work Zones and Decontamination (Demonstration). Critical
to the safe completion of field activities are work zones and
decontamination. Although each site has a unique approach,
uniform procedures are emphasized. A standard Level B/C de-
contamination setup is demonstrated.
• Health and Safety Plans (Exercise). Workers prepare a Health
and Safety Plan that is used in the field exercise.
• Field Exercise. An exercise in which workers practice the con-
cepts mentioned in the lectures is conducted. A Team Leader,
a SHSC and a Work Crew are designated; tasks and goals are
assigned. These tasks include, for example, sampling or collect-
ing air samples. Workers operate available equipment and set-
up various site situations such as decontamination and work
zones.
• Personnel Protection and Safety (Problem). A problem is pre-
sented based on the Health and Safety Plan and the field exer-
cise in which participants are required to make field related
safety decisions.
• Certification Examination. An examination is given that meas-
ures each worker's ability to conduct field activities in a safe
manner. The results and the individual's overall performance
in the course are used to assign site/activity certification.
ON-THE-JOB AND REFRESHER TRAINING
The most relevant and cost-effective training for HWS work-
ers is on-the-job (OJT) training. This is a system where less ex-
perienced workers participate in actual field work with more
experienced workers. Also, workers can gain experience in higher
levels of protection while working on lower level sites, i.e., wear-
ing Level B on a Level D site. In this way, the impact of a mistake
is much less, and workers gain valuable experience. Refresher
training in key subject areas (such as respirator use) is conducted
on a routine basis.
SITE-SPECIFIC TRAINING
Site-specific training is a requirement for all HWS workers,
including subcontractors. This type of training is usually in the
form of a briefing at the startup of site work. Topics generally
include a discussion of: the Health and Safety Plan; the nature of
site specific hazards; safety related duties; site work zones; hand-
ling emergencies; emergency contacts, e.g., medical; rules and
regulations for vehicle use; dealing with third parties, e.g., visitors
and the press; and using equipment. Workers also practice spe-
cific site procedures, such as contamination.
WORKER CERTIFICATION
Upon fulfillment of the medical surveillance, training and res-
pirator fit test requirements and successful completion of the cer-
tification examination, workers are certified to perform HWS
activities at either Level A, B, C or D. The HSM normally pro-
vides the written certification. Also, depending upon the exper-
ience and training level, workers are certified to either "super-
vise" HWS activities (-S designation) or "train" under super-
vision (-T designation). For example, workers certified to super-
vise Level C operations would carry a C-S designation. First aid/
CPR certification is a requirement for all -S designations.
SEMINARS 473
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HEALTH AND SAFETY RECORDS
Worker certification data and exposures/injuries should be
tracked on a computerized data base. The data base printout is
the controlling document in terms of authorizing workers to per-
form site work. Note that OSHA requires storage of health
records for 30 yr beyond the workers employment; therefore,
hard copies of all records and data entries need to be archived.
SITE HEALTH AND SAFETY PLAN
Each site must have a health and safety plan establishing re-
quirements for protecting the workers during all site activities.
The plan outlines all health and safety related procedures for the
site, specifies protective gear and monitoring requirements, and
supplies crucial right-to-know information to the worker. The
major elements of the site safety plan include a discussion of:
• Chemical Hazards—Wastes known or thought to have been
disposed, along with previous sampling results.
• Physical Hazards—Site specific physical hazards such as un-
safe footing, safety lines, test pit cave-ins, heat/cold stress,
noise or sharp objects.
• Other Hazards—Other hazards such as radiation, biological or
hospital wastes.
• Task Description—The location, schedule, level of protection
and specific techniques.
• Protective Equipment—Protective clothing associated with
each task and level of protection.
• Monitoring Equipment and Action Levels—The program that
will be implemented to monitor site hazards, including
"action" levels.
• Site Organization and Control—Work ureas (exclusion zone,
decontamination zone and support zone), access control points
and site security procedures.
• Decontamination Procedures—Procedures for personnel gear,
sampling and heavy equipment, including arrangements for the
proper disposal of contaminated materials.
• Site Personnel and Safety Responsibilities—Key personnel re-
sponsible for site safety.
• Site Emergencies—Actions to be taken and contacts to be made
in the case of an emergency.
CONCLUSIONS
A comprehensive health, safety and training program for HWS
workers has been outlined. The elements discussed include pro-
gram management, medical and exposure/injury surveillance, a
respirator program, a protective clothing program, site safety
monitoring, training, worker certification, maintenance of health
related records and the use of site specific safety plans. Compli-
ance with these requirements ensures that HWS workers are pro-
vided with a safe working environment and that individual firms
meet federal health and safety regulations.
474 SEMINARS
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1986 Exhibitors
ATEC Associates, Inc.
12«8 North Cobb Pkwy.
Marietta, GA 30062
404/427-9456
ATEC Associates, Inc. is a diversified engineering firm
with a staff of over 700 in 28 offices located in principal
cities throughout the United States. ATEC's Environ-
mental Services Division provides environmental con-
sulting and remedial action services that include en-
vironmental audits, RCRA permitting, remedial investi-
gations/feasibility studies, underground storage tank
management, asbestor surveys, landfill design, moni-
tor/recovery well design and installation, complete
analytical laboratory capabilities, geophysical testing,
solid/hazardous waste clean-up, in situ biological treat-
ment and asbestos abatement.
Acres International Corporation
424 Main St.
Suite 1000 Liberty Bldg.
Buffalo, NY 14202-3592 716/853-7525
Acres International Corporation, an internationally
known consulting engineering and project management
firm, provides services to the solid and hazardous waste
industry including: hydrogeological investigations,
groundwater monitoring and evaluations; design of
treatment systems and remediation programs; and facili-
ty closure planning.
Aero Vironment Inc.
825 Myrtle Ave.
Monrovia, CA 91016-3424 818/357-9983
Subsurface and atmospheric investigtions of hazardous
waste sites, leaking underground storage tanks and
waste incineration. Environmental audits. Special toxic
air pollutant field studies, including emission factor
determination, tracer studies and measurements by air-
craft. Simulation model development and application
for air and water. Permit application analyses and sup-
port; expert testimony.
Alchem-Tron, Inc.
7415 Bessemer Ave.
Cleveland, OH 44127 216/441-5628
Alchem-Tron, Inc. is an industrial waste dispos-
al/treatment/transportation and reclamation facility. It
has been in existence for over 8 years. We are a licensed
facility operating at two locations and serving most of
the eastern United States. Alchem-Tron offers its
customers a complete service package: disposal and
transportation of hazardous waste as well as analytical
services, consulting and clean-up services. Our staff is
Professional.
Alliance Technologies Corporation
213 Burlington Rd.
Bedford, MA 01730 617/275-5444 x4014
RCRA/CERCLA-related remedial engineering, field
sampling, laboratory analysis and groundwater monitor-
ing and modeling. Mobile hazardous waste laboratories.
Site investigations and air toxics monitoring. Complete
RCRA permit application assistance. Incinerator trial
burns. Closure and post-closure plans. Registered
Engineers, Geologists and Industrial Hygienists. AIHA
Certified Laboratory.
Alternative Technologies for Waste, Inc.
11300 S. NorwalkBlvd.
Santa Fe Springs, CA 90670 213/929-8103
ATW, Inc. is involved in the development of technolo-
gies to provide permanent solutions for the remediation
of hazardous waste. Through license agreements,
Calweld, Inc. and Toxic Treatments, Ltd. have acquired
the rights to manufacture, use and exploit the technolo-
gies which currently include equipment and processes
for: in situ detoxification of various subsurface and sur-
face contaminated wastes; in situ detoxification of
various hazardous waste sites; on-site treatment of
generating waste at the producing facilities.
American Fly Ash Company
606 Potter Rd.
Des Plaines, IL 60016 312/297-8811
American Fly Ash has over 40 years experience in ash
marketing and handling. Serving 15 utilities from more
than 30 sources in the central and northeastern United
States we can provide Class F and Class C fly ash for
waste stabilization or solidification applications.
Aqua-Tech Environmental Consultants, Inc.
181 S. Main St.
Marion, OH 43302 614/382-5991
Aqua-Tech Environmental Consultants, Inc. (ATEC)
was incorporated Oct. 1,1978 and chartered by the State
of Ohio on Dec. 18, 1978 for the purposes of testing,
analysis and assessment of aquatic and terrestrial en-
vironmental conditions, with recommendations for cor-
recting pollution-related problems. Aqua-Tech is
equipped to provide a broad range of analytical services
to its clients which consist of industries, municipalities,
government agencies and private individuals.
Art's Manufacturing and Supply
105 Harrison
American Falls, ID 83211 208/226-2017
AMS, the leader in hand-operated soil sampling equip-
ment for over 40 years, is now the leader in sampling
equipment for the hazardous waste industry. Stop by
Booth #208 and see the new patent-pending soil recovery
auger and our full line of completely stainless steel soil
sampling equipment.
BCM Engineers Inc.
1 Plymouth Meeting Mall
Plymouth Meeting, PA 19462 215/825-3800
Superfund Site Investigations • Groundwater Studies
• Remedial Design Engineering • Geophysical Sur-
veys • Asbestos Surveys • Analytical Services • Waste-
Water Treatment Design • Environmental Audits • Air
Quality Surveys & Design • Industrial Hygiene Surveys •
Wetlands Surveys • Site Health & Safety Plans.
BONDICO, Inc.
2410 Silver St.
Jacksonville, FL 32206
904/358-2602
BONDICO, Inc. has introduced a 90-gallon container
system designed for transportation, storage, treatment
and disposal of hazardous materials and low-level rad-
wastes. A dual laminate composite of polyethylene and
fiberglas, the container provides superior safety and ex-
traordinary cost-effectiveness with multiple reuse, in the
hazardous waste market. For radwaste, as a 7A type A
package, BONDICO's system provides benefits and per-
formance that will set new standards. This unit may be
utilized as a salvage container, on-site storage, transfer
container, tool crib or as an encapsulate via its innova-
tive on-site sealing system. BONDICO's container with
its fully removable lid, is rustproof, leakproof, corro-
sion resistant, lightweight, nestable and reusable.
BatteUe Pacific Northwest
Laboratories
P.O. Box 999
Richland, WA 99352 509/375-2867
BatteUe Pacific Northwest Laboratories offers a wide
variety of R&D and technical application services in-
cluding site characterization and assessment for active
and inactive sites, health effects assessments, and pro-
cess control and remediation technologies. BatteUe of-
fers advanced technology coupled with a cost-effective,
multi-discipUnary approach for solving waste-site
cleanup problems.
Beelman Truck Company
P.O. Box 93
St. Libory, IL 62282 618/768-441 1
Eighty years of transportation experience has made the
Beelman organization one of the largest bulk carriers in
the midwest specializing in transporting hazardous
materials. 300 + late-model, weight efficient units with
trained personnel assure dependable service — compe-
titively priced. Dumps, tanks, flatbeds and vans
available to handle bulk and containerized shipments.
Beltran Associates, Inc.
1133 E. 35th St.
Brooklyn, NY 11210
718/338-3311
Beltran Associates, Inc. manufactures electrostatic
precipitators and heat exchangers. Beltran's tubular
electrostatic precipitator (ESP) is used for the collection
of the sub-micron particulates generated in solid and liq-
uid waste incinerators. It is the only ESP on the market
which will collect particulates, HC1, SO2, and acid mist
in a single vessel. Various construction materials are
Available, including conductive FRP. Air-to-air and air-
to-water heat exchangers are available for the extraction
of heat from particulate-laden exhaust gases.
Bergen Barrel & Drum Company
43-45 O'Brien St.
Kearny, NJ 07032 201/998-3500
Try our "Super Shipper" and our Company on for size.
EXHIBITORS 475
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This unique line of Polyethylene Drum* offered by
Bergen Barrel & Drum Co. ranges from 15 gallon
through 55 gallon sizes. Also featured is the "Enviro-
pack" Salvage Drum which safely stores, transports and
disposes hazardous wastes whether through Incineration
or landfill.
Bird EivlronmuUI Systems, lac.
100 Neponset St.
S. Walpole, MA 02071 617/668-0400
Bird Environmental Systems, Inc. will be displaying its
new concept for its mobile waste dewatering plants
which includes total support such as laboratory facilities
to analyze waste streams, 24-hour service, parts and
repair, on-site technical support and purchase, lease or
rental financing packages available.
Black * V catch
1500 Meadow Lake Pkwy.
Kansas City, MO 64114 913/339-2000
A nationwide consulting firm providing complete
engineering services pertaining to hazardous waste
management including remedial investigations, feasibili-
ty studies, design of remedial actions, oversight of
remedial actions, RCRA services, regulatory and permit
support, and litigation assistance. Other specialties in-
clude waste treatment, waste-to-energy systems, public
health evaluations and facility closure services.
Brr*oa iBdustrtal Services, IK.
411 Burton Rd.
Lexington, SC 29072 800/845-5037
Bryson Industrial Services, Inc. is a hazardous waste
management company. We provide consultation and
management services to customers on methods of reduc-
ing, handling and disposing of their hazardous waste. In
addition, we provide secure permitted transportation
and fully trained and experienced project teams for on-
site service needs.
CECOS UterutioaiU, IK.
2321 Kenmore Ave.
Buffalo. NY 14207 716/873-4200
CECOS International, Inc., is a company specializing in
the treatment and disposal of hazardous chemical waste.
CECOS makes these services available to industry
through a network of regional treatment centers across
the United Slate* and Puerto Rico. CECOS offers
specialized hazardous waste capabilities, research and
analytical and consulting services.
CH2M HILL, IK.
P.O. Box 4400
Reston, VA 22090 703/471-1441
CH2M HILL is a consulting engineering rum with over
40 offices throughout the world. With extensive ex-
perience in hazardous waste site investigations and
cleanup, CH2M HILL provides services to both public
and private sector clients. CH2M HILL is the primary
contractor to U.S. EPA for Superfund sites in the west-
em United States.
Calgon Carboi Corporation
P.O. Box 717
Pittsburgh, PA 15230 412/787-6700
Calgon Carbon Corporation supplies activated carbon
products, systems and services, and air strippers to
remove soluble organic compounds from contaminated
groundwater, surface water or waste water.
Camp Drawer A McKet
One Center Plaza
Boston, MA 02108 617/742-5151
COM provides comprehensive engineering and manage-
ment services to public and private clients. Our hazar-
dous waste services include remedial investigations,
feasibility studies, site cleanup management, RCRA per-
mitting, computerized groundwater modeling, aquifer
restoration, risk assessment, underground storage tank
evaluation and remediation, environmental audits,
waste reduction and expert testimony.
CarbonAir Services, lac.
P.O. Drawer 5117
Hopkins, MN 55343 612/935-1844
CarbonAir Services provides treatment design and In-
stallation for system removal of vapor or aqueous phase
organic contaminants in groundwater, surface water or
air process streams. Treatment alternatives Include Car-
bon Adsorption, Packed Column Alrstripplng, and/or
any ancillary equipment such as multi-media filtration.
Emphasis is on system design and turnkey installation.
Carnow, Conlbear and Associates, Lid.
333 W. Wacker Dr.
Chicago, IL 60606 312/782-4486
Carnow, Conibear and Associates. Ltd., with offices in
Chicago, Washington, D.C. and Los Angeles, provides
consulting services to address occupational and environ-
mental health concerns associated with hazardous wasie.
CCA evaluates health effects due to exposure to hazar-
dous substances, designs and implements medical sur-
veillance programs, provides medical exams, trains
employees, develops and implements site safely and
health plans, offers industrial hygiene services and ex-
perl testimony.
Central Mist E^alpnenl
6200 North Broadway
St. Louis, MO 63147 314/381-5900
Central Mine Equipment Company manufactures drill
rigs and drilling tools for geo-exploration and monitor-
ing well installation: high torque multi-purpose auger-
core-rotary drill rigs, hollow-stem and continuous flight
augers, rotary and core drilling tools, soil sampling and
testing tools.
Century Laboratories, IK.
P.O. Box 248
1501 Orandview Ave.
Thorofare, NJ 08086 609/848-3939
Century Laboratories is an independent environmental
testing laboratory providing Priority Pollutant, RCRA,
water and wasiewaier and hazardous waste analysis.
Century is equipped with state-of-the-art instrumenta-
tion including GC/MS. GC, Atomic Absorption, ICP
and HPLC capability. Field sampling and sample pick-
up services are also available.
Chcnrb Technotogki, IK.
2424 Edenbom Ave., Suite 620
Metairie. LA 70001 504/831-3600
Chemfix Technologies, Inc. (CTI) offers the patented
CHEMF1X* process for chemical fixation/stabiliza-
tion of both hazardous and nonhazardous liquids and
sludges. Complete mobile services are offered, as well as
fixed plant facilities for continuous generation waste
streams. CTI services include site assessments, waste
stream characterization and permitting support.
Chemical Waste Management, Inc.
3003 Butterfield Rd.
Oak Brook, IL 60521 312/654-8800
Chemical Waste Management, Inc. is the world's largest
company involved in the analysis, transportation, treat-
ment and disposal of hazardous wastes. The company's
ENRAC division specializes in remedial cleanup projects
and offers on-site treatment as well as off-site treatment
and disposal.
Chromanetlcs Scientific Products
(C7I7A N. Blackhorse Pk.
Williamstown, NJ 08094 609/728-6316
Complete catalogue of laboratory supplies for the en-
vironmental firm. Product lines include sampling de-
vices, volumetric glassware, extraction glassware, (AA,
1R, UV, CC, HPLC instruments-accessories), analytical
standards, glass and plastic containers, lab furniture and
numerous other products.
Clayton Environmental Consultants, Inc.
25711 Soulhfield Rd.
Southfield. MI 48075 313/424-8860
Environmental Consulting Services: environmental risk
assessment • hazardous A solid waste management •
underground storage tank management • water re-
sources and wastewater engineering • environmental
audits for preacquisilion, mergers, foreclosures and in-
ternal review • PCB sampling, cleanup and decon-
tamination • groundwater contamination studies • water
and wasiewaier sampling • statistical sampling of soils
and waste piles • health and safety plans • regulatory in-
terpretation and negotiation.
Cku Sites, IK,
I199N. Fairfax St., MOO
Alexandria, VA 22314 703/683-8522
CSI is the independent, non-profit organization helping
to speed the cleanup of hazardous waste sites. It pro-
vides assistance in achieving private party settlements,
prepares and reviews cleanup plans and mamgn dean'
ups. The integration of these services reduces the cost of
cleanup.
Coabutfoi Engineering
1515 Broad Si.
Bloomfieldd. NJ 07003 201 /893-2962
Combustion Engineering announces a new business
unit. Environmental Systems and Service*, to serve the
growing environmental market. Through it, C-E pro-
vides full environmental consulting services, hazardous
site cleanup capabilities and the systems necessary to ad-
dicts hazardous waste issues in the public and private
sectors.
3308 E. Chapel HOI Hwy.
Research Triangle Park. NC 27709 919/549-8263
CompuChem Laboratories is the ' world's largest
laboratory specializing in hazardous waste analysis by
GC/MS. With its extensive experience in the field, Com-
puChem is able to provide a range of analytical labora-
tory services 10 meet the needs of clients in the following
areas: Superfund waste site analysis; RCRA; priority
pollutant analysis; identification of unknown wastes;
groundwaier monitoring; dioxin analysis; and waste site
screening. Among CompuChem's clients are the U.S.
EPA and many of the largest consulting engineering
firms and industrial corporations in America.
Coanne Eartnxaantal
91 Rosdand Ave.
Caldwell, NJ 07006 201/226-1522
Converse Professional Group: Converse Environmental
East; Converse Environmental Consultants California.
Converse offers a broad range of geologic and engineer-
ing services 10 solve environmental problems and regula-
tory compliance issues relating to groundwater contam-
ination and aquifer restoration. Additional environmen-
tal services include hydrogeological and underground
lank investigations.
CrtaafBJM Pup Company
P.O. Box 1051
Gfendive, MT 59330 4067365-3393
CrisafulU pumps the most viscous waste from your
ponds or tanks. Recently they pumped chemical waste
with a solids percentage in the high thirties. Whether
your project is waste removal or stabilization, Crisafulli
will be your best pump. Use their toll-free number—
1-800-442-7867—for prompt, courteous attention.
Crow* Aadcnoi IK.
306 Dividend Dr.
Peachtree City, GA 30269 404/997-2000
Crown Anderson Inc. offers rotational molded poly-
ethylene tanks and containers, incinerator scrubbing sys-
tems, spray dryers for waste liquids, waste heat recovery
and cogeneration equipment, as well as engineering ser-
vices and turnkey systems for handling, storage, and de-
struction of toxic, hazardous, radioactive and chemical
wastes.
Dames and Moore
7101 Wisconsin Ave.
Bethesda. MD 20901 301/652-2215
Dames A Moore, environmental engineering and applied
476 EXHIBITORS
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earth sciences consultants, offers a broad range of
hazardous and radioactive waste management services.
Services include hazardous waste facility remediation
program design and implementation, groundwater char-
acterization, geologic and geohydrologic investigations,
hazardous waste facility design, permitting assistance
and RCRA/CERCLA compliance assessments.
DART
61 Railroad St.
P.O. Box 89
Canfield, OH 44406 216/533-9841
DART is a multiservice organization, with its origins in
the transportation business. Serving all 48 continental
United States, DART is also one of the nation's largest
hazardous waste haulers, providing over 300 pieces of
equipment, including dump trailers, flatbeds, drop deck
vans, bulk pneumatics, etc. DART also serves as a
transportation broker, energy broker and services the
environmental industry with distribution of sorbents,
solidification material and IBM-compatible software
that tracks hazardous material and wastes, generating a
printed manifest.
Dohnnann Div. XERTEX Corp.
3240 Scott Blvd.
Santa Clara, CA 95054
408/727-6000
Dohrmann's Total Organic Carbon (TOC) and Total
Organic Halide (TOH) analyzers are designed for
RCRA-compliance monitoring of water for pollutants,
using EPA methodology. Our DX-20B Total Halide
analyzer is specifically configured for the rapid and ac-
curate determination of chlorine in waste oils and
solvents. The DC-180 represents the latest in automated
TOC analyzers, using proven UV-persulfate oxidation.
The DC-90 high-temperature TOC analyzer features low
blank and high throughput.
Dorr-Oliver Inc.
77 Havemeyer Ln.
Stamford, CT 06904 203/358-3357
Mobile Biological Wastewater Treatment Systems for
ground and surface water treatment.
Du Pont Company/Environmental
Service
External Affairs-Nemours Bldg., #2464
Wilmington, DE 19898 302/774-7150
Through its Environmental Services operation, Du Pont
treats wastewater and contaminated equipment on a
contract basis at its EPA-permitted Chambers Works
facilities, Deepwater, NJ. The 40-million-gallon-a-day
Wastewater Treatment Plant destroys industrial
wastewater chemicals through the patented Powdered
Activated Carbon Treatment (PACT) process. The
Thermal Decontamination Unit removes organic
chemical residuals from equipment through high-tem-
perature treatment.
Du Pont Company/Teflon
1007 Market, Rm. NA235
Wilmington, DE 19898 302/774-2692
Components^ manufactured from 100% virgin Du Pont
TEFLON® fluorocarbon resins used in the Ground
Water Monitoring Industry insure that representative
groundwater samples are obtained. Displayed will be
dedicated bladder pumps, bailers, transfer tubing, cas-
ing and screen of 100% TEFLON® manufactured by
various companies serving the Ground Water Monitor-
ing Industry.
Duke University Press
6697 College Station
Durham, NC 27708 919/684-2173
Duke University Press was founded in 1921 as Trinity
College Press, and celebrates in 1986 sixty-five continu-
ous years of publishing leading books and journals on a
variety of topics. Duke University Press currently
publishes more than 40 books and 12 journals annually,
and has some 350 titles in print.
Dunn Geosclence
5 Northway Ln., North
Latham, NY 12110 518/783-8102
Dunn Geoscience's geotechnical investigations at
CERCLA and RCA sites range from modeling pollutant
transport to characterizing the hydrogeologic envir-
onment for remedial designs and environmental assess-
ments. A quarter-century of excellence in subsurface
resource consulting is the firm's foundation for profes-
sional contributions to hazardous waste remediation.
E.C. Jordan Co.
562 Congress St.
Portland, ME 04112
207/775-5401
Solid and hazardous waste management services provid-
ed to industry and government agencies include geo-
physical and geohydrological investigations, record
searches, chemical characterization, contamination risk
assessment, identification and evaluation of remedial ac-
tion alternatives and implementation plans at hazardous
waste sites. Hazardous waste TSD facilities are devel-
oped from initial planning stages, through site selection
and investigation, design, permit application and con-
struction management.
EBASCO Services Incorporated
160 Chubb Ave.
Lindhurst.NJ 07071 201/460-6485
EBASCO Services Incorporated is a full-service con-
sulting, engineering and construction company offering
toxic materials, hazardous and mixed waste manage-
ment service. These services include remedial investiga-
tions, feasibility studies, chemical and environmental
engineering, geotechnical and geohydrological con-
sulting, project management and construction, environ-
mental planning, consulting and design, quality assess-
ment, financial and other specialties.
ECOVA Corporation
15555 NE 33rd
Redmond, WA 98052 206/882-4364
On-site hazardous and toxic waste management com-
pany specializing in providing the most advanced tech-
nological solutions for the on-site treatment of hazar-
dous and toxic waste.
ENRECO, Inc.
P.O. Box 9617
Amarillo, TX 79105 806/379-6424
ENRECO uses specially designed equipment to inject
and thoroughly mix fixation/solidification chemicals in-
to existing waste lagoons. These chemicals convert the
liquid or semi-liquid waste into a solid soil-like material.
Our process has been used for remedial action as well as
for treatment of wastes prior to landfilling on-site.
ENSCO, Inc.
1015 Louisiana St.
Little Rock, AR 72202
501/375-8444
The company provides integrated hazardous waste man-
agement services to private industry, public utilities and
governmental entities. These services include chemical
analysis, collection, transportation, storage, processing
and incineration of hazardous waste. The company also
provides transformer decommissioning and other waste
management services, including the reclamation of aban-
doned or problem waste sites, and engineering and con-
struction services for itself and others. The company has
developed and is currently marketing modular incinerators
for use at hazardous sites.
ENSECO
5530 Marshall St.
Arvada, CO 80002 303/421-6611
ENSECO, Inc. provides nationwide laboratory services
from facilities in Boston, MA; Berkeley Heights, NJ;
Richmond, VA; Houston, TX; Denver, CO; and Sacra-
mento, CA. ENSECO specializes in providing con-
sultative analytical chemistry and aquatic toxicology ser-
vices to solve environmental problems for industrial clients
and governmental agencies. The corporation also has
capabilities in industrial hygiene, pharmaceutical
chemistry, gas analysis and industrial problem solving.
Earth Resources Consultants, Inc.
P.O. Box 16961
Orlando, FL 32861 305/295-8848
Earth Resources Corporation (ERC) is a full service
hazardous materials management firm specializing in the
containment, treatment and removal of all types of
hazardous materials. ERC has a highly trained profes-
sional and technical staff experienced in the design and
implementation of innovative solutions to today's waste
problems. ERC's remedial action capabilities include
but are not limited to soil, groundwater, facilities, con-
tainerized wastes and pressurized gas cylinders.
The Earth Technology Corporation
3777 Long Beach Blvd.
Long Beach, CA 90807 213/595-6611
The Earth Technology Corporation offers comprehen-
sive hazardous waste management services. Those which
we are most frequently requested to provide include: en-
vironmental auditing/compliance assessment, hazar-
dous waste permitting, remedial investigations, remedi-
al/corrective action, design and engineering, geotechni-
cal investigations, waste stream reduction and recovery,
facility closure and laboratory and special technical ser-
vices.
Ecology and Environment, Inc.
P.O. Box D
Buffalo, NY 14225
716/632-4491
E & E offers the complete range of hazardous waste
engineering and technical services: site investigations;
remedial plans and specifications; construction manage-
ment; hydrogeological studies; groundwater, surface
water and air monitoring, etc.; RCRA compliance audit-
ing; underground storage tank management programs;
asbestos programs; emergency spill response services;
analytical laboratory services. E & E has offices from
coast to coast and in 14 foreign countries.
Eldredge,Inc.
898 Fernhill Rd.
West Chester, PA 19380 215/436-4749
Eldredge, Inc., provides the services of waste manage-
ment, transportation and environmental contracting
which include a diversified fleet permitted in 17 states,
project management, pollution abatement programs,
and cleanup/restoration of industrial waste sites.
Engineering-Science
57 Executive Park South, NE
Atlanta, GA 30329 404/325-0770
Engineering-Science (ES) is a major, full service, na-
tional and international environmental engineering firm
providing complete services in hazardous waste manage-
ment. ES has offices in 15 domestic locations conveni-
ently located to serve industry, military and governmen-
tal clients. ES is active in supporting industrial and
military clients in all phases of site/remedial investiga-
tions, feasibility studies, remedial action plan prepara-
tion, site cleanup/closure and post-closure activities.
Enviresponse, Inc.
110S. Orange Ave.
Livingston, NJ 07039 201/533-2385
Enviresponse, Inc., contractor for the U.S. EPA's En-
vironmental Emergency Response Unit in Edison, NJ,
offers a wide range of technologies and expertise rele-
vant to the complex problems surrounding the treatment
of hazardous and toxic waste. Services range from con-
sulting to design and construction. Enviresponse, Inc. is
a subsidiary of the Foster Wheeler Corporation.
Envirite Field Services, Inc.
600 W. Germantown Pk., #221
Plymouth Meeting, PA 19462 215/825-8877
Envirite Field Services provides solidification/fixation
services for organic and/or inorganic industrial wastes.
The company offers three proprietary delivery systems
to stabilize waste liquids, sludges and contaminated soils
EXHIBITORS 477
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with selected additives—the VR/STM system for low-
range solids, the PF-5TM system for mid-range solids,
and the HSSTM system for high-range solids. The com-
pany also provides dewatering services using mobile
filter presses.
Environmental Management Ntwi
225 N. New Rd.
Waco, TX 76710 817/776-9000
Environmental Management News, a bi-monthly news-
letter reaching environmental managers responsible for
the management and control of air, water, wastewater,
pollution and hazardous materials.
Occupational Health and Safety Magazine, a monthly
publication reaching over 92,000 Safety Managers, In-
dustrial Hygienists, Occupational Physicians and Occu-
pational Nurses.
Environmental Science A
EnglMcrinf, IK.
P.O. Box ESE
Gainesville, FL 32602 904/332-3318
BSE, a full service multidiiciplinary environmental
engineering firm, has performed work at more than 120
hazardous waste sites including 15 CERCLA NCP sites.
Capabilities include remedial investigations; feasibility
studies, QA/QC plans; safety and health planning and
monitoring; community relations; analytical services;
and expert witness testimony.
EertrouKaUJ Technology Inc.
Second and Maury Sts.
Richmond. VA 23224 804/231-2232
Environmental Technology, Inc. is a diversified envir-
onmental engineering firm that supplies geotechnical
consulting, environmental engineering, and municipal
and industrial services. Services include petroleum,
chemical and waste tank evaluation, decontamination,
removal and disposal. We also provide site assessment,
remedial action alternatives, cost estimates and compli-
ance monitoring closure plans.
Earlroiafe Services, Inc.
115 Gibraltar Rd.
Honbam. PA 19044 215/441-5924
Envirosafe Services, Inc.—hazardous waste manage-
ment through a variety of subsidiaries: ACES
—Associated Chemical A Environmental Services
—provides remedial services, spill cleanups, bio-
technology, groundwater filtration, site maintenance,
lagoon closures and underground storage tank excava-
tion. Fondesiy Enterprises, Inc.—disposal services for
hazardous/non-hazardous wastes, landfarm
capabilities. Enviromfe Serried of Idaho, Inc.—
(ESI I) secure disposal services for PCB-contaminated
materials.
EariroMK Maufement Corn.
333 Ganson St.
Buffalo, NY 14203 716/854-3611
Envirosure's remedial services begin with careful consid-
eration of total job scope and risk potential in perform-
ance of our total project management proposal.
Analytical services and procedures become essential to
remedial action as ground and surface water quality
identification may be required. Effective remedial on-
site operations personnel who are experienced and
highly trained in total project management and field
supervision. Envirosure's specialty transportation and
disposal options coincide and complement one another,
as we are able to provide transport vehicles specific to be
moved off-site for final treatment and duposal.
Evergreen Safety Systems, Inc.
P.O. Box 1207 303/422-2185
Arvada, CO 80001-1207 800/525-8696
Mobile decontamination units for personal hygiene in-
volving hazardous materials. Standard 6 & 12 person
models as well as customized self-contained units which
include the negative air concept with HEPA or activated
carbon filter. All units are constructed of first class
materials and meet or exceed EPA & OSHA re-
quirements.
F.C. Will Associates, Ltd.
Maple St. Industrial Pk., P.O. Box 128
Coal City, IL 60416 815/634-8567
F.C. Witt Associates Ltd. manufactures corrosion resis-
tant liners for tanks, pits, floors and trenches, and small
ponds. Materials are resistant to acids, alkalines, U.V.
and hydrocarbons. All liners are custom fabricated. One
to two day emergency service available.
Federal Ore A Chemicals, Inc.
117 Fifth Ave.
Belle Fourche, SD 57717 605/892-2743
A major producer of western sodium bentonite day
used as a containment material for toxic and hazardous
wastes. Federal Bentonite has been used in slurry trench
cut-off walls, landfill and lagoon linings and tank farm
impoundments to provide an extremely low permeability
barrier. The products include Ultra Seal* . Slurry
Mud* 90 A 125. Marine Seal* . PPS and Akwaseal*
The Foxboro Company
151 Woodward Ave.
South Norwalk.CT 06856 203/853-1616
Instrumentation for providing quantitative and
qualitative information on hazardous waste and spill site
contaminants. The instruments can be used at the waste
site to locate areas of high vapor concentration, to iden-
tify and determine concentration levels of various or-
ganic compounds, and to provide rapid, reliable field
screening/analysis for volatile hydrocarbons in ground-
water samples.
FroehUng A Robertson, Inc.
3015 Dumbarton Rd.
Richmond, VA 23261 804/264-2701
FroehUng A Robertson offers the services of profes-
sional engineners. chemists, construction inspectors,
geotechnical engineering and drilling. Capabilities in-
clude: preliminary assessments, site investigations,
RCRA studies and monitoring programs, landfill pro-
jects, etc.
Fote Pumps, Inc.
P.O Box 550
Lewistown. PA 17044 717/248-2300
Small Diameter Sampling Pump. Fultz Pumps. Inc. is
the manufacturer of 1'/«" diameter and 2Vi" diameter
stainless steel and teflon* sampling pumps. The pump
units are complete with 100' vinyl hose (teflon*
available), 24V power system, charger and lightweight
backpack. The complete units are one-man operable and
very portable. Optional equipment available.
GATecnnotofles
P.O. Box 85608
San Diego, CA 92138 619/455-3353
Circulating bed combustor systems. Circulating bed
technology has been used to destroy a variety of hazar-
dous solids, liquids, sludges and slurries, including
PCBs in soil, refinery wastes and pesticides. U.S. EPA
requirements for RCRA A TSCA materials are met
without the use of wet scrubbers or afterburners.
GAI Consultants, Inc.
570 Beatty Rd.
Monroeville, PA 15146
412/856-6400
GAI Consultants, Inc. and its subsidiaries provide engi-
neering consulting services In the areas of solid and
hazardous waste management, federal and state permit-
ting assistance, and disposal site design services including
remedial investigations and feasibility studies, hydrogeo-
logic investigations, site selection and cost optimization
evaluations, and site operation and closure plans.
CSX Chemical Services, Inc.
121 Executive Center Dr., #100
Columbia, SC 29210 803/798-2993
Principal lines of chemical waste business are high tem-
perature incineration; secure chemical landfill operation;
chemical waste collection and transfer; emergency
remedial and technical services. From its facilities in
Maryland. North Carolina, South Carolina and Tennes-
see, GSX provides a full range of analytical, admin-
istrative and transportation services to ensure regulatory
compliance by Us customers. In S.C. GSX owns the
largest commercial liquid waste incinerator in the
southeast designed to destroy a wide range of Uquid waste
streams. Also in S.C., GSX operates one of the nation's
largest secure chemical landfills. It meets all new, stringent
federal regulations. In N.C. GSX's Emergency, Remedial
and Technical Response Group is one of the primary
response units for chemical spills and ckanups in that
stale. The group provides nationwide remedial services to
private industry, including analysis, development of
cleanup plans, decontamination of buildings and equip-
ment, handling of explosives, landfill closure and the
cleanup of storage tanks and surface impoundments. In
addition, the group provides services for the disposal of
household hazardous wastes.
Geo-Coa, Int.
P.O. Box 17380
Pittsburgh. PA 15235 412/244-8200
Geo-Con is a full-service construction company that
specializes in the containment, removal and stabilization
of all types of hazardous wastes. With an extensive
background nationwide in hazardous waste remedial
work and the construction of new containment systems,
Geo-Con offers owners and consulting engineers ex-
perience and expertise that is unique in the industry.
CroSynltc, Inc.
3050 SW 14lh PI.
Boynton Beach. FL 33435 305/732-9910
GeoSyntec is an independent plastics testing laboratory
staffed by experts in materials science, plastics engineer-
ing and polymer chemistry. The company is dedicated to
the forensic analysis, research and development and
testing (conformant*, quality control, mechanical.
chemical compatibility and hydraulic properties, etc.) of
geosynthetks. including geomembranes, geotextiles,
geonets, geogrids and geocomposites used in landfill and
impoundment systems.
GeoSyntec's facilities consist of mechanical, physical,
hydraulic and chemical testing laboratories.
Geonki Limited
1745 Meyerside Dr.. 18
Missiuauga, Ontario
Canada L5T 1C5 416/676-9580
Geonks Limited, a world leading manufacturer of elec-
tromagnetic geophysical equipment, present their
Ground Conductivity Meters EM31, EM34-3 and EM38
with digital data logging system providing a rapid data
processing and contaminant plume contour mapping
capability. The EM39 Borehole Conductivity Meter pro-
vides accurate delineation of the contaminant plume and
monitoring capability.
GncahoTM * O'Msn, Inc.
9001 Edmonston Rd.
Greenbdt, MD 20770 301/982-2800
Greenhorne A O'Mara. Inc., an engineering design firm,
was founded in 1950 by A. James O'Mara and Marcus
F.H. Greenhorne (deceased). The company has grown
steadily through the years and today provides multi-
disciplinary services nationally in both public and
private sectors. The firm, currently ranked 71st in the
United States, has 12 offices and a staff of over 811.
Professional services include: architecture, automated
information, construction services, earth sciences, land
development, landscape architecture, water resources,
surveying, photogrammetry, planning, and civil, en-
vironmental, structural and transportation engineering.
Groandwater Decontamination System
140 Rt. 17, N., Suite 210
Paramus, NJ 07652 201 /265-6T27
Introducing Groundwater Decontamination Systems
(GDS), the unique new system for soil and groundwater
decontamination. The GDS process eliminates hydro-
carbon and halogenated hydrocarbon contaminants
from groundwater and soil through a process of ac-
478 EXHIBITORS
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celerated biodegradation by micro-organisms existing in
the contamianted soil. Patent awarded.
Candle Lining Systems Inc.
1340 E. Richey Rd.
Houston, TX 77073 800/435-2008
713/443-8564
Gundle Lining Systems Inc. is recognized as the World
Leader in the manufacture and installation of High Den-
sity Polyethylene lining systems. Gundle manufactures
HOPE in 22.5 feet seamless widths from 20 to 100 mil
thick. Also, Gundle manufactures and installs Driline
and Gundnet Drainage Net for leachate collection
systems. For the past 22 years, Gundle Lining Systems
has manufactured and installed over 300 million square
feet of lining systems using the advanced Extrusion
Welding Machine. • For more information, call
800/435-2008 or 713/443-8564.
HARCO, Corp.
P.O. Box 721
Medina, OH 44258
216/725-6681
HARCO Corporation, established in 1948, the recog-
nized world leader in the field of corrosion control and
cathodic protection, provides services and materials on a
worldwide basis. Full professional engineering, from in-
vestigation through design and cathodic protection
system maintenance, plus construction services and a
complete line of quality materials are available through
15 domestic and 6 international locations. HARCO
Corp. World Headquarters, 1055 W. Smith Rd.,
Medina, OH 44256, 216/725-6681.
Harza Environmental Services
150 S. Wacker Dr.
Chicago, IL 60606 312/855-5200
Harza Environmental Services, Inc. (HES) provides a
broad range of consulting engineering services in the
management of hazardous and solid waste. Planning
and design through construction and start-up are pro-
vided for remediation, new facilities, and facility expan-
sions. As a wholly-owned subsidiary of Harza Engineer-
ing Company, this multidisciplinary group of engineers,
scientists and technicians develops practical solutions to
hazardous and solid waste management problems. Other
Harza companies are available to HES when additional
expertise is needed.
Hazco, Inc.
1347 E. Fourth St.
Dayton, OH 45402 513/222-1277
Hazco is a national turn-key supplier of all the health
and safety equipment required to safely respond to a
remedial project or emergency haz-mat incident. Ser-
vices include site specific PPE packages delivered from
stock; 24-hour access to our Tech Service via 1-800-
332-0435; rental of HNUs, OVAs, instruments, and de-
con trailers; and our Safety Network Approved Purchas-
ing Plan (SNAP). Our experience is your advantage!
HAZCON Engineering, Inc.
P.O. Box 947 800-28-SOLID
Katy.TX 77492 713/975-8404
HAZCON, Inc. specializes in solidification of organic
hazardous waste and conversion of sludges and fluids in-
to a solid mass resembling concrete. Tests have shown
the resultant mass is leach-resistant and practically
impermeable. Toxicity is dramatically reduced, and in
most cases there is little increase in volume after treat-
ment.
HDR Infrastructure, Inc.
8404 Indian Hills Dr.
Omaha, NE 68114 402/399-1000
HDR Infrastructure, Inc. specializes in industrial and
hazardous waste management, including remedial inves-
tigations and feasibility studies of hazardous waste sites;
design and implementation of remedial action alter-
natives; hazardous waste facility permitting; design of
hazardous waste treatment, storage and disposal facili-
ties; and closure/post-closure planning for hazardous
waste management facilities. HDR's industrial projects
encompass the study, design and implementation of in-
dustrial waste treatment, ultra pure water, gas and
chemical systems; control of toxic emissions; environ-
mental permitting; and process/process support facili-
ties for high-tech industries.
Hazardous Materials Control
Research Institute
9300 Columbia Blvd.
Silver Spring, MD 20910 301/587-9390
HMCRI is a unique, public, nonprofit, membership
organization which promotes the establishment and
maintenance of a reasonable balance between expanding
industrial productivity and an acceptable environment.
Our goals are met through a variety of publications,
conferences, workshops, newsletters, equipment exhibi-
tions and other information dissemination programs.
We provide members and all other interested persons
with a distinctive forum in which they can exchange in-
formation and experiences dealing with hazardous ma-
terials. "Join HMCRI today!!"
HNU Systems, Inc.
160 Charlemont St.
Newton, MA 02161 617/964-6690
Model IS101 portable intrinsically safe photoionization
analyzer, GP101 portable general purpose photoioniza-
tion analyzer, PI101 portable photoionization analyzer,
301P portable compact gas chromatograph, 331 com-
pact dedicated capillary gas chromatograph, 321 com-
pact temperature programmed gas chromatograph.
Hanson Engineers, Inc.
1525 S. Sixth St.
Springfield, IL 62703 217/788-2450
HEI provides environmental/waste management, geo-
technical, geological, hydrogeological, civil, hydrologic
and structural engineering consulting services to in-
dustry and government clients. Services at hazardous
waste sites include: site characterization; remedial inves-
tigations; feasibility studies; design and supervision of
remedial action; hydrogeology studies; impoundment
studies, design, plans and construction monitoring;
underground tank management—spill control, counter-
measure plans (SPCC) and tank retirements; ground-
water monitoring, sampling and modeling; stabilization
studies; and geotechnical laboratory testing of con-
taminated soils.
HAZTECH, Inc.
5280 Panola Industrial Blvd.
Decatur, GA 30035-4013 404/981-9332
HAZTECH, Inc., a hazardous waste cleanup contrac-
tor, offers services such as contaminated soil removal,
on-site treatment, tank testing and cleaning, lagoon
closure, sludge solidification and buried waste and drum
excavation. HAZTECH also provides 24-hour emergen-
cy spill response, mobile incineration and dewatering
services, site assessment and lab pack removal.
Hewlett-Packard Co.
2 Choke Cherry Rd.
Rockville, MD 20850 301/921-6296
Hewlett-Packard will exhibit a gas chromatography
system for analysis of purgeable halocarbons and
aromatics in wastewater and drinking water. The unit
consists of a gas chromatograph, purge and trap device,
electrolytic conductivity detector and photoionization
detector. Also we will exhibit a gas chromatograph/
mass spectrometer for environmental analyses.
Hoyt Corporation
251 Forge Rd.
Westport, MA 02790 617/636-8811
Solvent Vapor Recovery/Air Pollution Control Equip-
ment; Distillation Equipment; Odor Control Equip-
ment.
I-Chem Research
104 Quigley Blvd.
New Castle, DE
302/322-3808
A complete line of sample bottles, jars and vials, sup-
plied with teflon-lined closures attached and available
chemically cleaned and treated to exact U.S. EPA pro-
tocols. Also available custom-cleaned to your exact
specifications. I-Chem Research is supplier of pre-
cleaned sample bottles, jars and vials to the U.S. Super-
fund program nationwide.
ICAIR, Life Systems, Inc.
24755 Highpoint Rd.
Cleveland, OH 44122 216/464-3291
ICAIR, Life Systems, Inc. (ICAIR) specializes in human
health and environmental effects assessments (endanger-
ment, public health, toxicity, contamination, en-
vironmental and risk and impact assessments). ICAIR's
uniqueness is in its approach, integrating the experience
of ICAIR's core scientific and management staff with
the finest scientific and technical minds in the world.
ICF Technology
1850 K St., NW
Washington, DC 20006 202/862-1100
ICF Technology—the scientific and engineering subsidi-
ary of ICF Incorporated—consults on environmental
and hazardous waste management issues. We provide
our clients with a full range of technical services, from
site-specific investigations and risk assessments to
remedial design and construction monitoring. The firm
is headquartered in Washington, D.C.
ICOS Corporation of America
4 West 58th St.
New York, NY 10019 212/688-9216
Slurry walls, slurry trenches, drilling, grouting, bored
piles, load-bearing elements, tieback anchors, sewer
rehabilitation, shotcrete, Envirowall.
INFORM
381 Park Ave., S.
New York, NY 10016 212/689-4040
INFORM is a non-profit research organization that
reports on practical actions for the preservation and
conservation of natural resources. We conduct
seminars, provide speakers for conferences, and are fre-
quently called upon to brief committee's such as the
U.S. Senate Environmental & Public Works, and the
U.S. House of Representatives Committee on Energy
and Commerce. Our research is published in books,
abstracts, newsletters and articles in major business, en-
vironmental and industry publications.
In-SItu, Inc.
P.O. Box I - 210 S. 3rd St.
Laramie, WY 82070-0920 800/4-INSITU
In-Situ, Inc. began as a consulting firm providing com-
puter modeling hydrologic evaluation, and laboratory
R&D services in in-situ mining and related energy in-
dustries. In-Situ has broadened its technological base to
include the development and sale of state-of-the-art
hydrologic instrumentation and software, to provide
time-sharing services to clients through its Computer
division.
Industrial Training Systems Corporation
20 West Stow Rd. 800/922-0782
Marlton, NJ 08053 609/983-7300
Industrial Training Systems Corporation produces and
markets audiovisual training programs for industry in
the areas of health, safety and the environment. Our
library of over 80 slide/tape and live action video pro-
grams includes Hazard Communication training, acci-
dent prevention, environmental programs and more.
Our Training and Consulting Services Department con-
sists of a staff of certified consultants that can provide
stand-up training at your location.
Inorganic Ventures, Inc.
P.O. Box 1432
Brick NJ 08723 201/364-3643
Inorganic Ventures provides QC & calibration trace
metals standards for EPA, CLP and OSHA protocols.
EXHIBITORS 479
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These standards have been developed by Spectra. Spec-
tra provides on-slte training for EPA, CLP and OSHA
protocols. Representatives from Inorganic Ventures and
Spectra will be present to discuss your specific needs.
Inlelhu Corporation
3355 Michelson Dr.
Irvine, CA 92715 714/975-6000
Intcllus serves both government and industry with a
comprehensive range of environmental services in-
cluding: underground tank services, hazardous material
management, environmental engineering, regulatory
analysis and permitting, environmental auditing and risk
management. Intellus has an extremely broad base of ex-
perience, and has completed a multitude of complex
study and design projects for clients In manufacturing,
natural resources, biotechnology, transportation,
petrochemical and many others.
International Cbem Pack Corp.
10500 Tube Dr.
Horst, TX 76053-7910 817/267-3319
ENV1ROPACKTM (DOT-E 9341) Polyethylene Salvage
Drum • ENVIROTANKTM (DOT-E 9519) Portable,
250 and 350 Gallon. Polyethylene Shipping Containers
with Steel Framework.
Inleraittoul Technology Corporation
23456 Hawthorne Blvd. 209-211
Torrance. CA 90505 213/378-9933
International Technology Corporation (IT) is the na-
tion's premier firm devoted exclusively to the manage-
ment of hazardous substances and situations. Through
37 offices nationwide, IT serves both government and
industry with a comprehensive range of services in-
cluding analytical; engineering; risk control; decontam-
ination and remedial; and transportation, treatment and
disposal.
JWI.be.
2155 112lh Ave.
Holland, MI 49423
616/772-9011
JWI, located in Holland, Michigan, manufacturers of
process equipment filter presses for solid liquid separa-
tion, dryers for volume production of hazardous waste.
JWI also manufactures continuous blending equipment
for sludge stabilization as well as portable mixers for
general mixing application.
Jacobi EagbMeriag Grasp, Inc.
1511 KSt., NW, Suite 1100
Washington, DC 20005 202/783-1560
Jacobs Engineering Croup, Inc., an international envir-
onmental engineering and construction firm, has exten-
sive experience, particularly with respect to the remedia-
tion of hazardous waste sites, and provides engineering
services to evaluate sites, characterize the nature and ex-
tent of contamination, and develop remedial action plan
alternatives, including cleanup design.
Janes T. Warring Soas, lac.
4545 "S" St.
Capitol Heights, MD 20743 301 /322-5400
All types and sites of containers—new and recondi-
tioned—fiber, sleel. plastic. Our hazardous waste con-
tainers are DOT approved and range in size from 5 to 83
gallons. We accept orders from one to truck loads and
we ship anywhere. You order a container—we don't
have it—it's special—we will get it for you. No order is
too small for James T. Warring Sons, Inc. Let us help
you contain your hazardous waste. WE CAN IT!!
Kramer Environmental
935 Allwood Rd.
Clifton, NJ 07012 201/471-9500. X203
Kramer Environmental, a division of Kramer Industries,
provides "total" environmental services. Our compre-
hensive range of services includes chemical disposal,
remedial action, laboratory analysis, drum handling in
our new transfer and storage facility (TSDF EPA ID N
O. NJD065825341), technical services, and transporta-
tion. For more information contact: Kramer En-
vironmental, 935 Allwood Rd., Clifton, NJ 07012,
201/471-9500.
LEFCO WESTERN
4901 Cripple Creek
Houston, TX 77017 713/941-8442
LEFCO WESTERN pumps sludge!—as a design-builder
of material-moving systems such as Sludge Buster and
V.A.M.M. These systems have a 100-foot boom reach
and are capable of moving up to 8OT« solids with
distances in excess of 5,000 feet. Our pumping systems
are self-contained and can be placed almost anywhere.
LOP AT Enterprises
1750 Bloomsbury Ave.
Wanamassa, NJ 07712 201/922-6600
Manufacturer of K-20 brand products for the control
and prevention of leaching and migration of hazardous
toxic substances. For application in soil-like paniculate
matter and on various cementilious surfaces. The easy-
to-apply proprietary products are recommended for use
in the control of PC Hi and other chlorinated organic
compounds, and toxic heavy metals—lead, mercury,
chromium.
Law Engineering Testing Company
P.O. Box 888013
Atlanta, GA 30356 404/396-8000
Law Engineering Testing Company assists clients with
their hazardous and nonhazardous waste concerns.
specializing in seven core business areas: Hazardous and
Solid Waste Management • Groundwater Hydrology
and Resource Development • Surface Water Hydrology
and Water Quality Protection • Land Treatment of
Wastes • Ecological Assessment • Geophysical Explora-
tion • Seismic Hazard Evaluation.
Lawkr, Matusky A SkeUy Engineers
One Blue Hill Plaza
Pearl River, NY 10965 914/735-8300
Lawler, Matusky & Skelly Engineers is an environmental
science and engineering consulting firm founded in
1965. LMS offers comprehensive services in waste
management and groundwater resource planning in-
cluding consultation and assistance in developing
regulatory compliance programs. LMS provides con-
tamination assessment; preliminary site assessment: field
sampling and monitoring for wastes, soils, groundwater
and surface waters; remediation design; environmental
and risk assessment; modeling and statistical evaluations
of data; permit assistance; QA/QC compliance and pro-
cedures; oversight services; and other engineer-
ing/biological and groundwater services.
Layne-Western Company, Inc.
5800 Foxridge Dr.
Mission, KS 66202
913/362-0510
Layne-Western Company, Inc. provides a full range of
professional services associated with hazardous waste in-
vestigations, remedial actions and site monitoring.
Working with consulting engineers, major industrial
concerns and municipalities. Layne's trained and ex-
perienced personnel) can provide expertise with any
drilling method, sampling technique and well design.
Laync also brings to each project complete site safety
plans, quality control and assurance methods and full
project documentation.
The Lion Group
P.O. Drawer 700
Lafayette, NJ 07848
201/383-0800
Tank and Line Compliance: precision certified tank
testing. Underground storage tank removal and retro-
fitting, predictive assessments. Leak prevention, detec-
tion and correction. Inventory reconciliation and turn-
key tank management systems. Soil and hydrogeological
services, cleanups, monitoring systems and contingency
plans. Site assessments, training workshops and envir-
onmental management systems.
Liquid Wail* Technologies, Inc.
P.O. Box 282
Blackwood, NJ 08012 609/227-4711
Liquid Waste Technologies offers a line of product! for
organic stabilization, extraction of hydrocarbons from
soil, and oil spill cleanup. Oil Bond-100 reacts with a
wide variety of petroleum and oil-based wastes. It
changes the physical characteristics of the waste to that
of a solid, it will not revert back to a liquid, or release
liquid, under conditions of pressure, water contact, cold
or heat within acceptable limits for storage or disposal
of the waste.
MAC CorponltoaVSalarB
Shredder DIvUo*
201 E. Shady Grove Rd.
Grand Prairie, TX 75050 214/790-7800
MAC Corporation's Saturn Shredder Divsion manufac-
tures low-speed, high-torque, rotary shear-type shred-
den designed to produce required size reduction ap-
plications for light metals, ferrous and non-ferrous,
plastic, wood, rubber, glass, paper for recycling pur-
poses and provide resource recovery or waste to energy
assistance for hazardous, nuclear, municipal or in-
dustrial solid waste. Innovative effective systems for
proper waste reduction is Saturn's expertise.
MAECORP iBcorponlcd
17450 S. Halstead St.
Homewood, IL 60430
312/957-7600
MAECORP Incorporated provides all services required
in the cleanup of hazardous waste sites and hazardous
material (chemical) problems. The services themselves
are of a technical problem-solving nature, applied in a
"hands-on" fashion. Chemical decontamination of
facilities and equipment: hazardous material handling,
including pumping, packaging, etc. On-site field chem-
ical treatment, including incineration, detoxification,
neutralization, in situ vitrification, fixation, ultra-violet
peroxidaiion, biological degradation, reclamation and
grouadwaier recovery. Hazardous material spill recov-
ery and transportation.
MDS Adraand AaalytJa, tee.
Two Dundee Park
Andover, MA 01810
617/470-1390
MDS Advanced Analytics, Inc. specializes in mobile
analytical services and offers on-site solutions to com-
plex environmental and chemical process monitoring
problems. The company is dedicated to providing the
highest quality mobile chemical detection and analytical
services designed to efficiently solve your monitoring
needs.
MSI DetoxUlcattoa Incorporated
100 Erik Dr.
Bozeman, MT 59715
406/586-4766
MSI Detoxification Incorporated (MDI) is a full-service
hazardous waste site detoxification company. MDI's
services extend from legal and technical problem defini-
tion, to integrated emergency responses/remedial inves-
tigations, to feasibility studies based on state-of-the-art
analyses of site parameters and alternative technologies,
to total site detoxification based on a unique biological
technology and complementary technologies which will
significantly lower detoxification costs.
MTA Remedial Resoorces, Inc.
(MTARRI)
1511 Washington Ave.
Golden, CO 80401 303/279-4255
MTA Remedial Resources, Inc. is a remedial action con-
tractor that provides: safe and cost-efficient execution
of remedial action projects • application of alternative
technology available today • detoxification of con-
taminated material on-site or in situ to reduce the
volumes requiring handling • reduction of long-term
liabilities • recovery of useful or valuable minerals.
480 EXHIBITORS
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Marcel Dekker, Inc.
270 Madison Ave.
New York, NY 10016 212/696-9000
Marcel Dekker, Inc. will be displaying new titles in-
cluding Economic Methods for Multipollutant Analysis
and Evaluation (Baasel), Materials Recovery From
Municipal Waste (Alter) and Reducing the Carcinogenic
Risks in Industry (Deisler) among other new titles. Dis-
count order forms are available at the booth.
Marine Pollution Control
8631 W. Jefferson Ave.
Detroit, MI 48209 313/849-2333
Marine Pollution Control was one of the first cleanup
companies in the United States. We have developed into
a mobile rapid response oriented company, capable of
responding to diverse conditions. We are able to handle
oil and chemical incidents in land or water environment.
We now possess high capacity pumping for emergency
response conditions—3000 GPM for h'ght products and
capable of pumping coal tar.
Mar; Ann Llebert, Inc. Publishers
1651 Third Ave.
New York, NY 10128 212/289-2300
Mary Ann Liebert, Inc. publishes journals, books and
news publications in the most exciting and new areas of
science and medicine. One of the journals, Hazardous
Waste & Hazardous Materials, edited by Norman
Beecher, Sc.D., is the official journal of the Hazardous
Materials Control Research Institute. This journal is the
central source of information for advancing technology,
providing economical and ecological methodology for
the regulation and management of hazardous waste and
related hazardous material.
Med-Tox Associates, Inc.
1401 Warner Ave., Suite A
Tustin, CA 92680 714/669-0620
Med-Tox Associates, Inc. offers services in industrial
hygiene, toxicology, and occupational medicine. Health
and safety plans, both generic and site specific are
developed. Toxicological risk assessment, medical
surveillance and training for hazardous waste site per-
sonnel are provided.
MetcalfA Eddy, Inc.
P.O. Box 4043
Woburn, MA 01888 617/246-5200 x4007
Engineers & Planners: Hazardous Waste Management
-Program Management - Contract Ops - Privatization
-Sludge Management - Water & Wastewater Manage-
ment - Roads/Bridges - Transportation - Facilities.
Mineral By-Products, Inc.
777 Franklin Rd.
Marietta, OA 30067 404/424-0247
Mineral By-Products, with headquarters in Marietta,
Georgia and offices in Dayton, Ohio and Gary, Indiana,
supplies PozzalimeTM from numerous strategic loca-
tions. PozzalimeTM is effective for neutralization and
meets the RCRA requirements as a solidification
material for most hazardous and non-hazardous bulk
liquids.
Model Management/Scientific
Publications
P.O. Box 23041
Washington, DC 20026-3041 703/620-9214
There are more than 70 groundwater programs available
to analyze groundwater data, store well records in data
bases, simulate groundwater flow and well fields and
model groundwater contamination. These programs are
in use with state and Federal agencies, universities and
consulting companies in: Canada, USA, England, Ger-
many, Sweden, Norway, South America, India and they
are also used by the United Nations.
Modern Industrial Plastics
3337 N. Dixie Dr.
Dayton, OH 45414
513/226-8009
Modern Industrial Plastics will exhibit products for
groundwater monitoring made from Teflon® . These
products include MIP casing and screen material sold
through stocking distributors, a bladder pump made en-
tirely of Teflon with pump controller and a bailer of all
Teflon. See us in booth 105.
Morris Industries, Inc.
777 Rt. 23
Pompton Plains, NJ 07444 201/835-6600
The Morris Monitor Well Locking Cap is designed to
give maximum security. Welded tamper-proof with all
heavy gauge steel, it is available in above-ground and
flush-mount models. Both will accommodate your own
standard security padlock. Popular sizes are in stock.
NAC Northeastern Analytical Corp.
234 Rt. 70
Medford, NJ 08055 609/654-1441
Northeastern Analytical Corp. (NAC) provides techni-
cal support for hazardous waste projects. The Field Ser-
vices Group is experienced in all facets of air/soil/
waste sampling and tank testing. The NAC Industrial
Hygiene Group can manage the health and safety pro-
gram. The laboratory provides complete chemical
analysis of site samples.
NUS Corporation
910 Clopper Rd.
Gaithersburg, MD 20878 301/258-1299
NUS Corporation, a Halliburton company, offers com-
prehensive remedial services using proven engineering
and planning techniques which ensure health, safety and
regulatory compliance. From process control and risk
assessment to community relations and emergency plan-
ning, our extensive experience means cost-effective solu-
tions. The record: over 2,000 site and field assessments,
scores of remedial investigations, feasibility studies and
project engineering for problems such as chemical spills,
leaking underground storage tanks, sludge pits and land-
fills. Our staff of over 1,500 specialty engineers, scien-
tists and technicians brings years of on-site experience to
government and industry, making NUS a top resource
for hazardous waste consulting expertise.
Nanco Labs, Inc.
Unity St. at Rt. 376
P.O. Box 10
HopeweU Junction, NY 12533 914/221-2485
Nanco Labs provides quality, cost-effective en-
vironmental analyses to clients throughout the United
States. Nanco is a contract laboratory to the U.S. EPA,
the New York State DEC and the New Jersey DEP.
Nanco specializes in HSL, priority pollutant and RCRA
analyses.
National Draeger, Inc.
P.O. Box 120
Pittsburgh, PA 15230 412/787-8383
National Draeger, Inc., a U.S. subsidiary of
Draegerwerk AG, located in Luebeck, West Germany,
has earned a worldwide reputation for being the leader
in manufacturing specialized equipment and systems
which enable, support and protect human breathing
safety. By introducing innovative new products for gas
detection and warning systems, breathing protection,
filter technology, diving equipment, air supplied systems
for aviation and space technology as well as medical
equipment, Draeger helps to upgrade safety standards
for the entire safety industry.
National Environmental Health
Association
720 S. Colorado Blvd., S. Tower
Suite 970
Denver, CO 80222 303/756-9090
National Environmental Health Association is a na-
tional, nonprofit organization of environmental health
professionals who work to control environmental
hazards so as to attain optimum human health.
Members are employed by federal, state and local
governments, schools, medical care facilities, the
military, industries and are educators and students of
environmental health.
National Institute for Occupational
Safety and Health
4676 Columbia Pkwy.
Cincinnati, OH 45226 513/684-8328
Employees work safely at a hazardous waste site if they
are informed of the hazards involved, receive necessary
training, follow the proper procedures, use the required
personal protective equipment and remain aware of the
conditions or situations around them at all times. The
NIOSH exhibit includes recommendations for the con-
trol of occupational hazards, including the NIOSH
Hazardous Waste Sites and Hazardous Substance
Emergencies-Worker Bulletin. Information will be
available for NIOSH Recommended Criteria, Current
Intelligence Bulletins, Technical Reports and our data
base.
National Lime Association
3601 N. Fairfax Dr.
Arlington, VA 22201 703/243-5463
The National Lime Association exhibit provides infor-
mation on the use of lime for hazardous waste treat-
ment. The principal use of lime is the neutralization of
inorganic acidic waste and the precipitation of heavy
metals. Lime and fly ash form a pozzolanic material
which can be used to solidifv a hazardous sludge.
Nytest Environmental
75 Urban Ave.
Westbury, NY11590 516/334-7770
An independent laboratory providing complete
analytical services for the screening and analysis of
hazardous waste. The laboratory is equipped with so-
phisticated computerized GC/MS systems including ex-
tensive automated allied instrumentation enabling it to
perform analytical programs thoroughly, competently
and quickly.
O.H. Materials Co.
16406 US Rt. 224 East
Findlay, OH 45840 419/423-3526
Environmental Services: Groundwater Recovery and
Treatment; On-site Treatment Equipment; Hazardous
Waste Site Cleanup; Facilities Decontamination;
Biological Treatment; Technical Advisory Services;
Laboratory Services; Emergency Response; Surface Im-
poundment Restoration; Explosives/Reactives Hand-
ling; Underground Storage Tank Management—from
response centers in Massachusetts, New Jersey, Virginia,
Florida, Georgia, Alabama, Louisiana, Texas, Ohio,
Michigan, Minnesota, Missouri and California.
Occupational Hazardous Magazine
1111 Chester Ave.
Cleveland, OH 44114 216/696-7000
A trade magazine serving the industrial safety, health,
hygiene and plant protection market.
Orlando Laboratories, Inc.
3444 McCrory PI., Suite 124
Orlando, FL 32803 305/896-6724
Orlando Laboratories is an analytical laboratory provid-
ing services to the public, engineering firms, government
agencies, industries and consultants. We endeavor to
utilize only the most modern analytical equipment in the
analysis of our client's samples. Our expertise includes
hazardous waste, facility monitoring and gas chroma-
tography/mass spectrometry confirmation.
OSCO, Inc.
P.O. Box 1203
Columbia, TN 38401 615/381-4999
Permitted hazardous waste transporter in 40 states. Over
70 trailers including van, flatbed, roll-off, and acid,
flammable and vacuum tankers. LTL available. Hazar-
dous liquid treatment plant in Columbia, TN accepts
acids, bases and other aqueous wastes. Complete labora-
EXHIBITORS 481
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tory. Lagoon closures and environmental consulting.
No assignment too small or too large.
P.E. LaMoreaux A Associates
P.O. Box 2310
Tuscaloosa, AL 35403 205/752-5543
P.E. LaMoreaux & Associates, Inc. (PELA), hydrolo-
gists, geologists and environmental scientiiu, offer
hydrological, geological, environmental and hazardous
waste consultation services throughout the world. Other
services include emergency spill response, sampling,
laboratory analysis, development of monitoring pro-
grams and installation of wells, reclamation, govern-
ment permitting, court lestimony and graphic and com-
munication programs.
Photovac International Inc.
739B Park Ave.
Huntington, NY 11743 516/351-5809
Photovac, the manufacturers of ultra-sensitive air
analyzers, will exhibit the new Total lonizables Present
Monitor TIP II which has multilamp capability and Is
rated for Div. II operation. The recently introduced
10S70 Portable Intelligent PID/GC with built-in modem
and RS 232 interface will also be demonstrated.
Pluming Research Corp.
303 E. Wacker Dr.
Chicago, IL 60601 312/938-0300
PRC, serving both government and industry, has ranked
among the 10 largest engineering firms in the country
since 1977. Headquartered in McLean, VA, PRC main-
tains 50 of flees in the U.S. Specialties include remedial
investigations/feasibility studio, risk assessments, com-
pliance audits, permitting support, environmental and
systems engineering, and program management support.
PoBatton Abatement ContulUnU
• Services
800 Orange St.
Millville, NJ 08332 609/825-1400 x2560
Manufactures sampling equipment for drums, tanks,
surface and groundwaters, sludges and solids. Also pro-
vides safety-coated sample containers, sample shipment
systems, environmental laboratory kits, apparatus and
accessories as well as personal protective equipment.
Poty-America
2000 W. Marshal]
Grand Prairie, TX 75051 817/640-0640
Poly-Flex is a polyethylene geomembrane liner (20-100
mils thick) which provides a cost-effective method of lin-
ing hazardous waste disposal facilities and preventing
groundwater pollution. Poly-Flex is manufactured by
Poly-America, one of the most modern extrusion facili-
ties in the U.S., producing 150 million pounds of poly-
ethylene per year. Poly-America's state-of-the-art qual-
ity control laboratory assures the finest quality
polyethylene liner available.
Prawn Filtration SpedaHsl
Incorporated
P.O. Box 686, 30 Mason St.
Torrington, CT 06790 203/489-1221 or 485-2524
Pressure Filtration Specialists, Incorporated (PFS)—
volume reduction of liquid waste. PFS's mobile, self-
contained, trailer-mounted filter presses reduce gen-
erator liquid sludge volume by producing filter cake of
35-60% solids by weight. This reduced volume offers
substantial savings to generators on transportation and
disposal costs. On-site sample testing available upon re-
quest.
Princeton Testing Laboratory
P.O. Box 3108
Princeton, NJ 08543 609/452-9050
Environmental analysis and industrial hygiene. Toxic
waste/soil, RCRA, NJ ECRA, industrial wastewater
NPDES, groundwater,OSHA workplace surveys, asbes-
tos monitoring and evaluation, complete NIOSH lab
methodology, stack testing, asbestos abatement training
courses, Right-To-Know compliance, microbiology.
AIHA accredited, NJ DEP Certified. NY DOH approv-
ed, PA DER approved.
QED Environmental Systems, Inc.
P.O. Box 3726
Ann Arbor, MI 48106 313/995-2547
Well Wizard* dedicated groundwater sampling
systems, Sample Pro* portable samplers and supplies,
and Pulse PumpTM pneumatic pumping systems for
leachate and contaminated water pumping are all fea-
tured in the QED Environmental Systems, Inc. line.
Well Wizard dedicated bladder systems and purging aids
are designed to meet the latest EPA sampling guidelines.
R.E. Wright Associates. Inc.
3240 Schoolhouse Rd.
Middletown, PA 17057 717/944-5501
R.E. Wright Associates. Inc. (REWAI) is an applied
groundwater consulting firm providing professional ser-
vices to conduct feasibility studies, site investigations,
permitting and implementing of remedial measures.
Capabilities include complete Held testing, aquifer
analysis, data collection, computer modeling and water
and wastewater laboratory analysis. REWAI also de-
signs and manufactures groundwater cleanup equip-
ment, including the Auto-Skimmer, Air-Stripping
Towers, Water Table Depression Pumps and Liquid In-
terface Samplers. The Auto-Skimmer automatically
recovers subsurface spills of floating hydrocarbons from
both large and small diameter wells.
Radian Corporation
P.O. Box 9948
Austin, TX 78766 512/454-4797
Technology-based company which provides professional
services and specialty products to government and in-
dustry. Full range of services offered in environmental
services, and specifically in the area of solid and hazar-
dous waste management. These services include the
areas of permitting; remedial action planning/imple-
mentation, soils, water, and waste analysis: and waste
management facilities design.
Recra Environmental, tec.
4248 Ridge Lea Rd.
Amherst. NY 14226 716/833-8203
Recra Environmental, Inc. is an independent firm sup-
plying waste management services to the industrial and
government communities in the form of professional
consulting and laboratory testing. Chemical Control
Management, waste minimization programs, site and
plant assessments and PRP assistance coupled with en-
vironmental testing and waste characterizations encom-
pass a portion of the services offered.
Resource Analysis, Inc.
P.O. Box 4778
Hampton, NH 03842 603/927-7777
Resource Analysts and its affiliates provide comprehen-
sive environmental testing service to industrial and com-
mercial clients and to all levels of government. Special-
ties include organic chemistry using IR, GC and GO MS
analytical methods; inorganic and heavy metals
chemistry; freshwater and marine aquatic toxicology;
and field sampling. The laboratories occupy a 10,000 sq.
ft. facility with a staff of 25 professionals.
Resource Technology Services
6 Berkeley Rd.
Devon, PA 19333
215/687-4592
RTS is a hazardous waste management company offer-
ing expertise in the following areas: laboratory waste
handling, laboratory services, drum and bulk waste and
reactive and explosive waste removal and disposal.
Remedial action and emergency response capabilities are
also offered.
Resources Conservation Co. is an environmental
systems engineering firm specializing in resource
recovery and environmental reclamation. RCC provides
complete services including laboratory testing, process
development, design engineering and turnkey construc-
tion. RCC's 15 years of experience has led to the
development of several patented processes such as
B.E.S.T. for hazardous sludge processing; the Brine
Concentrator for water recovery and waste reduction.
Dow Chemical's AquaDetox is also available for air/
stream stripping of volatile pollutants from wastewater.
Reuord-Esrrlm/EETC
5103 W. Beloit Rd.
Milwaukee. WI 53214 414/643-2668
Rexnord Breathing Systems offers the Biopak 60, one-
hour SCBA and the Biopak 240 four-hour SCBA. The
units are positive-pressure, light, compact, and easy to
use and maintain. Rexnord, through its wholly owned
subsidiary, Envirex, offers a broad range of ser-
vices—analytical lab, bench treatability, pilot plant tests
and scalcd-up. installed systems. Processes include
chemical treatment, solids separation and dewatering,
nitration, aeration, air stripping, adsorption and
desalting, if needed. Site-specific combinations of cost-
effective physchem/biological systems are offered.
Biological systems can be aerobic or anaerobic. Multi-
process mobile systems are also available. Envirex's Bio-
Norn ici Division offers mobile dewatering systems.
Rkdd Environ
P.O. Box 5007
Portland. OR 97208-3320
Ul Scrrfccs, IK.
503/286-4656
Resources Conservation Company
3101 NE Northup Way
Bellcvue, WA 98004
206/828-2225
RES provides diverse environmental services including
environmental consulting and engineering, ground-
water, remedial action and studies, hazardous waste
management, emergency response for oil or hazardous
waste spills or releases. Engineers, designs, installs and
operates petroleum hydrocarbon recovery systems. Pro-
vides services for industry and government from re-
gional offices in St. Louis. MO; Portland, OR; Rich-
mond and Los Angeles, CA.
RorF. Wnton, inc.
Weston Way
West Chester. PA 19380 215/692-3030
Managers of major environmental projects including fa-
cilities design, construction, operation, remedial ac-
tions, permitting, closures, investigations and analytical
chemical analyses.
S-R Analytical. Inc.
28 Springdak Rd.
Cherry Hill. NJ 08003 609/751-1122
S-R Analytical is a full service environmental laboratory
specializing in the analysis of environmental samples;
priority pollutant and HSL compounds, RCRA classi-
fication, hazardous waste characterization, and offers a
full range of field sampling and testing services.
SAIC
8400 Westpark Dr.
McLean, VA 22102 703/821-4749
SAIC is an employee-owned company principally in-
volved in the application of scientific expertise to solve
complex technical problems. SAIC offers a full range of
environmental consulting services including hazardous
waste site investigations and feasibility studies,
wastewater engineering, analytical chemistry, ground-
water modeling, risk assessments, regulatory compliance
and specialized laboratory studies.
SCS Engineers
11260 Roger Bacon Dr.
Reston, VA 22090 703/471-6150
Specialists in solid and hazardous waste management
since 1970. Services include remedial investigations,
feasibility studies, remedial action design and construc-
tion supervision. The firm provides permitting assistance
and prepares closure plans. SCS is one of a few national
firms offering subsurface gas migration control design and
construction services. Offices nationwide.
482 EXHIBITORS
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SMC Martin Inc.
900 W. Valley Forge Rd.
P.O. Box 859
Valley Forge, PA 19482 215/265-2700
SMC Martin Inc. provides engineering and geotechnical
services to industry and government including remedial
investigations and feasibility studies for hazardous and
solid waste disposal sites; wastewater treatment; envir-
onmental assessment; legal advisory services; permit ap-
plication assistance; environmental monitoring; con-
struction management; closure plan design; and engi-
neering/financial analyses.
SHE Analytics, Inc.
2910 Turnpike Dr.
Hatboro, PA 19040 215/674-1202
A full service testing laboratory serving the waste
management industry. Broad spectrum of analytical
capabilities ranging from drinking water analyses to
organic/priority pollutant analyses. State-of-the-art in-
strumentation includes GC/MS, GC, ICP, TOC and
TOX. Other services include contract research &
development and consulting.
'Sevenson Containment Corporation
2749 Lockport Rd.
Niagara Falls, NY 14302 716/284-0431
Sevenson Containment Corporation provides turnkey
services to government and industry in the areas of
hazardous waste management and waste site cleanup.
Sevenson's full service capabilities include: site restora-
tion; secure landfill construction; slurry wall & trench
construction; sludge solidification & fixation; waste
recovery and treatment; drum removal and waste ex-
cavation, transportation and disposal.
Shirco Infrared Systems, Inc.
1195 Empire Central
Dallas, TX 75247 214/630-7511
Shirco, Inc. incineration systems featuring the use of in-
frared heating and conveyor belt transport of waste
material through an efficiently insulated, modularly
constructed waste disposal system. Since no fossil fuel is
required, the reduced gas flow is economically treated to
meet requisite emission standards. Systems are excellent
for intermittent operation and have transportable
capability. Shirco Portable Pilot Test Unit is available
for on-site testing at your facility.
SlUdur North American Company
P.O. Box 1043
Elyria, OH 44036 216/277-0981
An imbankment stabilization process for stable and un-
stable soil conditions. It addresses all types of slips and
channel work very cost-effectively. It functions as a flexi-
ble concrete retaining wall that turns into a living wall.
Skolnlk Industries, Inc.
4601 W. 48th St.
Chicago, IL 60632-4896 312/735-0700
Manufacturer of Hazardous Material Containers from 8
to 85 US Gallon Capacities including "Big Mouth," the
85 Gallon Salvage Drum and "Quad-Pak," the assort-
ment of 4 nested containers. Also, the SECURITY
Drum accessories.
Soil & Material Engineers, Inc.
P.O. Box 609
Cary, NC 27511 919/481-0397
Soil & Material Engineers provides a comprehensive
range of environmental and geotechnical engineering
services to help you solve your hazardous substance
problems. We will interpret your responsibilities under
the regulations, investigate your hazardous substance
problems, and provide you with a cost-effective solu-
tion. We are ready to serve you—call us!
Sollnst Canada Ltd.
2440 Industrial St.
Burlington, Ont., Canada L7P 1A5 416/335-5611
Solinst manufactures high quality groundwater in-
strumentation. Solinst Water Level Meters offer fast,
accurate measurements using a ridged flat tape with
stainless steel conductors and permanent markings every
0.05 ft. The equipment ranges to include the Waterloo
Multilevel System for obtaining samples from many dif-
ferent levels in a single borehole in bedrock.
Southwest Research Institute
6220 Culebra Rd.
San Antonio, TX 78284 512/684-5111
Description of projects involving leak detection and liq-
uid waste impoundment (scale model demonstration of
electrical method for locating leaks in plastic liners).
Description of failure mode testing of geomembrane
materials.
Sybron Chemicals Inc.
Birmingham Rd., P.O. Box 66
Birmingham, NJ 08011 609/893-1100
Leaders in the application of Augmented Bioreclama-
tion (ABR) for the treatment of contaminated soil and
groundwater. Capabilities include biosystems engineer-
ing services and supply of selectively adapted organisms
for specific contaminants. Technology useful for clean-
up of chemicals from leaking storage tanks, pipeline
spills, train derailments, etc. Advantages are ultimate
disposal technology and low cost.
TAMS Engineering
655 Third Ave.
New York, NY 10017 212/2964371
TAMS, a leading international engineering firm, offers
comprehensive services in solid and hazardous waste
management. Capabilities include RI/FS; QA/QC;
Health/Safety; Risk Assessment; Community Relations;
Remedial Design; Construction Supervision; Site
Closure; Waste Geotechnics; Chemical/Process Design;
Watershed Management; Hydrogeology/Mathematical
Modeling. TAMS provides services to clients in govern-
ment, military and private sectors through offices in ma-
jor cities.
TRC Environmental Consultants, Inc.
800 Connecticut Blvd.
East Hartford, CT 06108
Environmental Consulting Services.
203/289-8631
Target Environmental Services, Inc.
5513 Twin Knolls Rd., Suite 216
Columbia, MD 21045 301/992-6622
Target Environmental is a leader in the development and
use of Soil Gas sampling and analytical techniques for
the detection of subsurface contamination. A highly ex-
perienced staff and an EPA-approved laboratory fur-
nish the technical quality required for a cost-effective
and accurate evaluation of the extent, composition and
concentration of soil and groundwater contamination.
Technos, Inc.
3333 NW 21st St.
Miami, FL 33142 305/634-4507
Technos specializes in contaminant hydrology, ground-
water and geologic hazards site investigations, and leads
the industry in the high resolution surface and downhole
geophysics, statistical geomorphology, complex and
fracture flow analysis, in situ contaminant and flow
measurements, and advanced groundwater modeling,
computer graphics and data processing.
Tetra Tech, Inc.
(A Honeywell Subsidiary)
630 N. Rosemead Blvd.
Pasadena, CA 91107 818-449-6400
Tetra Tech provides water resource and hazardous
material management services for industrial, institu-
tional and governmental clients throughout the U.S.
The firm's hazardous waste management services in-
clude: materials management, waste characterization,
emergency response, risk assessment, feasibility studies,
geohydrologic investigations, SPCC/contingency plans,
health and safety training.
Thermo Electron Instruments Inc. (AID)
108 South St.
Hopkinton, MA 01748 617/432-5321
Manufacturer of instruments both portable and sta-
tionary to measure organic toxic chemicals and air,
water and soil pollutants. Also manufactures ambient
and stack monitoring systems. Will feature Portable Gas
Chromatographs, Organic Vapor Analyzers and Total
Hydrocarbon Analyzers.
Tigg Corp.
P.O. Box 11661
Pittsburgh, PA 15228 412/5634300
Manufacturers of Modular Adsorbers designed for the
remediation of vapor and water pollution. The com-
bination of over 30 years of experience with adsorbents
and systems provides unique capabilities of technical ex-
pertise and product availability to address specific re-
medial problems with the most appropriate technology.
Toxic Treatment (USA) Inc.
901 Mariner's Island Blvd., Suite 315
San Mateo, CA 94404
415/572-2994
Toxic Treatment USA, Inc., (TTUSA), is a subsidiary
of Toxic Treatments Limited (TTL), an Australian-
based public company. TTL owns the technologies
developed by Alternative Technologies for Waste, Inc.
(ATW), and the In-Situ Detoxifier prototype built by
Calwed Inc. The equipment has been successfully field
tested removing concentrated hydrocarbons from con-
taminated soil. TTUSA is further developing and
marketing the In-Situ Detoxifier System.
U.S. Army Corps of Engineers
P.O. Box 103, Downtown Station
Omaha, ME 68101 402/221-7317
The U.S. Army Corps of Engineers and the U.S. EPA
have joined forces to clean up federal lead hazardous
waste sites under the Superfund program. The booth
will be manned by Corps personnel to assist architect-
engineer firms and construction contractors take advan-
tage of work available to them through the Corps of En-
gineers.
U.S. Army Environmental
Hygiene Agency
Aberdeen Proving Ground
Aberdeen, MD 21010 301/671-2024
U.S. Army Environmental Hygiene Agency, Waste
Disposal Engineering Division-Army and Department of
Defense worldwide support on the management and
disposal of hazardous and solid wastes, emergency spill
response, soil analysis and groundwater monitoring.
U.S. Environmental
Protection Agency
401 M St., SW
Washington, DC 20460 202/382-5100
The Superfund law provides the authority to respond to
problems at uncontrolled hazardous waste sites in
emergency situations and at sites where long-term per-
manent remedies are required. The Emergency Response
Team responds to releases which pose an immediate
threat to the public health and environment and pro-
vides R&D assistance in providing long-term remedies.
The long-term remedies are performed by states, the
U.S. EPA via the Army Corps of Engineers, or respon-
sible parties.
U.S. Geological Survey
790 National Center
Reston, VA 22092 703/648-4377
Panels depicting research and products of the U.S. Geo-
logical Survey dealing with earth sciences.
US Ecology, Inc.
P.O. Box 7236
Louisville, KY 40207 800/626-5 317
US Ecology, Inc., a subsidiary of American Ecology, is
a full-service waste management firm. The company
operates hazardous waste disposal facilities near
Robstown, TX and Beatty, NV. Both facilities accept
EXHIBITORS 483
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RCRA hazardous solid waste, and the Beany facility
also disposes of PCB waste and low-level radioactive
waste (LLRW). In addition, US Ecology provides
cleanup services for hazardous waste.
VFL Technology Corporation
42 Lloyd Ave.
Malvern, PA 19355 215/296-2233
VFL Technology offers solidification and stabilization
services for organic and non-organic liquids, sludges and
soils. In situ stabilization provides permanent chemical
encapsulation at a fraction of off-site disposal cosU.
Our field construction groups have developed and im-
plemented cost-effective on-site closures for impound-
ments ranging from 2 - 200 thousand cubic yards.
WAPORA, Inc.
1555 Wilson Blvd., Suite 700
Rosslyn, VA 22209 703/524-1171
WAPORA, a minority business enterprise, offers over
17 years of experience in the conduct of environment*!
investigations. WAPORA specializes in hazardous
wastes site investigations, remedial action planning,
regulatory negotiations and cleanup supervision. Our
offices are located in Washington, DC, Atlanta, Dallas,
Cincinnati and New Jersey.
Wstfbwortii/ALERT Laboratories. Inc.
1600 Fourth St., SE
Canton, OH 44707 216/454-5809
Since 1938, Wadsworth/ALERT Laboratories. Inc. has
offered independent laboratory analytical ser-
vices—meeting the needs of industry, government and
private concerns. WAL is a U.S. EPA Contract
Laboratory in the Superfund program, actively par-
ticipates with mobile lab services in ERCS Zones I, II
and III and maintains drinking water certifications
throughout the U.S. WAL has available 6 OC/MS
syitems, multiple GC units, industrial hygiene testing
and a complete wet chemistry lab. Programs include
'Appendix IX,' TCLP, RCRA, TSCA. SDWA, NPDES
and others. Rush services available.
Waile Convertloni, Inc.
2951C Advance Ln.
Colmar, PA 18915 215/822-2676
Waste Conversions, Inc. is a full-service environmental
management company offering services including con-
sulting, analysis, quality control, liquid treatment,
solidification, solids processing, oil recycling, drum
handling, lab packing, transportation, manifest exper-
tise, secure landfill, emergency response, on-site
dewatering, site evaluation, site cleanup, ECRA ser-
vices, regulatory Uaiion and tank cleaning.
Waile Documentation and Control, Inc.
P.O. Box 7363
Beaumont, TX 77706 409/839-4495
Waste Documentation and Control writes and markets
software for documenting hazardous and other waste
shipments. The system prints manifests, reports for
public agencies, accounting reports, specific format
reports and user-defined reports. The entire system is
customized to purchaser requirements. The system is
available for many single or multi-terminal computers.
Waste-Tech Scmcca, Inc.
18400 W. 10th Ave.
Golden, CO 80401 J03/279-97I2
We offer on-site combustion services using a fluidized
bed combustor that destroys both hazardous and toxic
wastes in solid, liquid, slurry and gaseous form. We of-
fer a worry-free service because we own, operate, per-
mit, maintain and service the transportable fluid bed
combustor.
Weitbay lulnunenli Ltd.
507 E. Third St.
N. Vancouver, B.C.
Canada V7L-1G4 604/984-4215
Westbay Instruments Ltd.—designers and manufactur-
ers of the MP system, a modular multiple level ground-
water instrumentation system for pressure measure-
menu and groundwater sampling. Components include
plastic or stainleu steel casing and couplings, inflatable
or mechanical packers and pneumatic or electric pres-
sure probes and sampling probes.
Wlbon Laboralorle*
525 N. 8th, P.O. Box 1884
Salina.KS 67401 913/825-7186
Full service analytical laboratory specializing in environ-
mental monitoring and the analysis of hazardous waste
samples. Expertise includes GC/MS, GC, HPLC and in-
dustrial hygiene. Participant in TCLP, zero headspace
extraction method validation study.
Woodward-Clyde CoBmlluU
201 Willowbrook Blvd.
Wayne, N J 07470 201 /785-0700 x450
Consulting Engineers, Geologists and Environmental
Scientists.
YWC.tac.
200 Monroe Tnpk.
Monroe, CT 06468 203/261 -4458
A multidisciplinary environmental laboratory/engineer-
ing consulting firm. YWC, Inc. provides air, soil, water
and waste characterization for full-profile site
assessments. The York Laboratories Division is a par-
ticipant in EPA's Contract Laboratory Program. Addi-
tional services available include contract operation of
wastewater treatment facilities, interim sludge dewater-
ing services, hazardous waste management and remedial
investigation/feasibility studies. Growth has been
achieved through dedicated personal service with an em-
phasis on quality at most competitive prices.
Yetow Sortep iHUwascstl Co.. UK.
P.O. Box 279
Yeflow Springs, OH 45387 513/767-7241
YSI manufactures a complete line of products for
precise, reliable measurement of conductivity, dissolved
oxygen and temperature using EPA, APHA and ASTM
apoproved methodology. YSI recently introduced the
Model 3000 T-L-C. a portable, self-contained instru-
ment for monitoring Temperature-Level-Conductivity
of groundwaler or surface water.
484 EXHIBITORS
-------
Author Index
This Author Index contains authors for the years 1980-1985 only.
Absalon, J.R., '50-53
Accardi, J., '85-48
Adamowski, S.J., '55-346
Adams, R.B., '84-326
Adams, W.M., '83-108
Adams, W.R., Jr., '82-377; '85-352
Adaska, W.S., '84-126
Adkins, L.C., '80-233
Ahlert, R.C., '82-203; '85-217; '84-393
Ahnell, C.P., Jr., '80-233
Ainsworth, J.B., '85-185
Albrecht, O.W., '87-248, 393
Aldis, H., '85-43
Aldous, K., '80-212
Alexander, W.J., '82-107
Allcott, G.A., '81-263
Allen, H.L., '87-110
Alvi, M.S., '84-489
Ammann, P., '84-330
Ammon, D., '84-62, 498
Amos, C.K., Jr., '84-525
Amster, M.B., '85-98
Anderson, A.W., '84-511
Anderson, D.A., '85-154
Anderson, D.C., '87-223; '85-154; '84-131,
185; '85-80
Anderson, J.K., '84-363
Apgar, M., '84-176
Appier, D.A., '82-363
Arland, F.J., '85-175
Arlotta, S.V., Jr., '85-191
Arnold, D.F., '84-45
Arthur, J., '84-59
Assink, J.W., '82-442; '84-576
Astle, A.D., '82-326
Atimtay, A., '85-464
Atwell, J.S., '85-352
Ayres, J.E., '87-359
Ayubcha, A., '84-1
Badalamenti, S., '85-202, 358; '84-489
Baer, W.L., '84-6
Bailey, P.E., '82-464
Bailey, T.E., '82-428
Bailey, W.A., '85-449
Balfour, W.D., '82-334; '84-77
Ballif, J.D., '82-414
Barbara, M.A., '85-237; '85-310
Bareis, D.L., '85-280
Barker, L.J., '82-183
Barkley, N.P., '82-146; '85-164
Barone, J., '84-176
Barrett, K.W., '87-14
Barth, D.S., '84-94
Bartley, R.W., '84-35
Bartolomeo, A.S., '82-156
Baughman, K.J., '82-58
Baxter, T.A., '84-341
Bayse, D.D., '84-253
Beam, P.M., '87-84; '85-71
Beck, W.W., Jr., '80-135; '82-94; '85-13
Becker, J.C., '85-442
Beckert, W.F., '82-45
Beckett, M.J., '82-431
Beers, R.H., '87-158
Beilke, P.J., '82-424
Bell, R.M., '82-183, 448; '84-588
Ben-Hur, D., '84-53
Benson, B.E., '80-91
Benson, R.C., '80-59; '87-84; '82-17; '85-71;
'85-112
Berger, I.S., '82-23
Berk, E., '85-386
Berkowitz, J., '85-301
Bernard, H., '80-220
Bernert, J.T., '84-253
Bhalla, S., '85-189
Bilello, L.J., '85-248
Billets, S., '84-45
Binder, S., '85-409
Bixler, D.B., '82-141; '84-493
Blackman, W.C., Jr., '80-91; '84-39
Blasland, W.V., Jr., '87-215; '85-123
Blayney, E.K.H., '85-476
Boa, J.A., Jr., '82-220
Bogue, R.W., '80-111
Bonazountas, M., '84-97
Bond, F.W., '82-118
Bonneau, W.F., '84-509
Bopp, F., Ill, '84-176
Borsellino, R.J., '85-299
Bort, R.M., '85-152
Bouck, W.H., '87-215
BoutweU, S.H., '85-135
Bove, L.J., '84-412
Bowders, J.J., '87-165
Boyd, J., '84-382
Bracken, B.D., '82-284
Bradford, M.L., '82-299
Bradshaw, A.D., '82-183
Brandwein, D.I., '80-262; '87-398
Brandwein, S.S., '82-91
Brannaka, L.K., '87-143
Braun, J.E., '84-449
Brenneman, D., '85-299
Bridges, E.M., '84-553
Brink, J.M., '84-445, 504
Brockbank, B.R., '84-371
Brodd, A.R., '82-268
Brokopp, C., '84-239
Brown, K.W., '87-223; '84-94, 185; '85-442
Brown, M.J., '82-363
Brown, S.M., '87-79; '85-135
Brack, J., '85-452
Brack, J.M., '84-72
Bruehl, D.H., '80-78
Brugger, J.E., '80-119, 208; '87-285; '82-12
Brunner, P.O., '85-43
Brunotts, V.A., '85-209
Brunsing, T.P., '82-249; '84-135
Bryson, H.C., '80-202
Buecker, D.A., '82-299
Buelt, J.L., '84-191
Buhts, R.E., '85-456
Buller, J., '85-395
Bumb, A.C., '84-162
Burgess, A.S., '85-331
Burgher, B., '82-357; '84-335
Burns, H., '85-428
Burrus, B.G., '82-274
Burse, V.W., '84-243
Bush, B., '80-212
Butler, H.P., '82-418
Butterfield, W.S., '82-52
Buttich, J.S., '84-200
Byers, W.D., '54-170
Byrd, J.F., '80-1
Caldwell, S., '87-14
Campbell, D.L., '85-36
Campbell, P.L., '84-145
Cane, B.H., '82-474
Caravanos, J., '84-68
Carter, J.L., '85-192
Carter, T.D., '85-63
Casteel, D., '80-275
Castle, C., '55-452
Cavalli, N.J., '84-126
Celender, J.A., '82-346
Chaconas, J.T., '87-212
Chan, R., '85-98
Chang, R., '85-97
Chang, S.S., '87-14
Chase, D.S., '85-79
Chieh, S-H, '84-1
Childs, K.A., '82-437
Cho, Y., '85-420
Christofano, E.E., '80-107
Christopher, M.T., '80-233
Chung, N.K., '80-78
Cibulskis, R.W., '82-36
Cichowicz, N.L., '80-239
Clark, R., '84-486
Clarke, J.H., '85-296
Clay, P.P., '87-45; '82.-40; '85-100
Clemens, B., '84-49, 335; '85-419
demons, G.P., '84-404
Cline, P.V., '84-217
Cochran, S.R., '82-131; '84-498
Cochran, S.R., Jr., '50-233; '85-275
Cohen, S.A., '87-405
AUTHOR INDEX 485
-------
Coldeway, W.G., '84-564
Cole, C.R., '87-306; '82-116
Collins, J.P., '87-2; '53-326
Collins, L.O., '83-398
Colonna, R., '80-30
Cook, O.K., '87-63
Cook. L.R., '83-280
Cooper, C., '87-185
Cooper, D., '85-419
Cooper, E.W., '83-338
Cooper, J.W., '82-244
Corbett, C.R., '80-6; 'S/-5
Corbo, P., '82-203
Corn, M.R., '8/-70
Cornaby, B.W., '82-380
Cothron, T.K., '84-452
Coutre, P.E., '84-511
Cox, G.V., '8/-1
Cox, R.D., '82-58, 334
Crawley, W.W., '84-131, 185; '85-80
Cudahy, J.J., '85-460
Cullinane, M.J., Jr., '84-465
Curry, J., Jr., '84-103
Czapor, J.V., '84-457
Dahl, T.O., '87-329
Daigler, J., '8J-296
Daily, P.L., '85-383
Dalton, D.S., '85-21
Dalton, T.F., '87-371
Davey, J.R., '80-257
Davis, B.D., '84-213
Davis, S.L., '84-449
Dawson, G.W., 'S/-79; '82-386; '83-453
Day, A.R., '83-140
DeCarlo, V.J., '85-29
DeGrood, T.J., '85-231
Dehn, W.T.. '83-313
Demmy, R.H., '87-42
Dempsey, J.G., '85-26
DeRosa, C., '85-412
Derrington, D., '84-382
Desmarais, A.M.C., '84-226
Devary, J.L., '83-117
Dickinson, R.F., '84-306
DiDomenico, D., '82-295
Diecidue, A.M., '82-354; '83-386
Dienemann, E.A., '84-393
Diesl, W.F., '80-78
Dikinis, J.A., '84-170
Dime, R.A., '83-301
DiNapoli, J.J., '82-150
DiNitto, R.G., '82-111; '83-130
DiPuccio, A., '82-311
Diugosz, E.S., '85-429
Dodge, L., '85-255
Dorrler, R.C., '84-107
Dowiak, M.J., '80-131; '82-187; '84-356
Doyle, D.F., '85-281
Doyle, R.C., '82-209
Doyle, T.J., '80-152
Drake, B., '82-350
Drever, J.I., '84-162
Driscoll, K.H., '8/-103
Duff, B.M., '82-31
Duffala, D.S., '82-289
Duffee, R.A., '82-326
Duke, K.M., '82-380
Duncan, D., '87-21
Dunckel, J.R., '85-468
Durst, C.M., '85-234
Duvel, W.A., '82-86
Dybevick, M.H., '83-248
Earp, R.F., '82-58
Eastman, K.W., '83-291
Eberhardt, L.L., '84-85
Eckel, W.P., '84-49; '85-130
Edwards, J.S., '85-393
Ehrman, J., '84-374
Eicher, A.R., '85-460
Eimutis, B.C., '87-123
Eissler, A.W., '84-81
Eklund, B.M.. '84-77
Eley. W.D., '84-341
Elkus. B., '82-366
Ellis, R.A., '82-340
Eltgroth, M.W., '83-293
Emerson, L.R., '83-209
Emig, O.K., '82-128
Emrich, G.H., '80-135
Eng, J., '84-457
Engels, J.L., '84-45
Engler, D.R., '85-378
English, C.J., '83-453; '84-283
Erbaugh, M., '85-452
Erdogan, H.. '85-189
Esposito, M.P., '84-486; '85-387
Ess, T., '82-390, 408
Ess, T.H., '87-230
Evans, J.C., '82-175; '85-249, 357, 369
Evans, M.L., '84-407
Evans, R.B., '82-17; '83-28
Evans, T.T., '84-213
Everett, L.G.. '82-100
Exner, P.J., '84-226
Fagliano. J.A., '84-213
Falcone, J.C., Jr., '82-237
Fang, H-Y, '82-175; '85-369
Farrell, R.S., '83-140
Farro, A., '83-413
Fast, D.M., '84-243
Faulds, C.R., '84-544
Feld, R.H., '83-68
Fell, G.M.. '83-383
Fellows, C.R., '83-37
Fenn, A.H., '85-476
Ferguson, J., '84-248
Ferguson, T., '80-255
Fields, S., '84-404
Figueroa, E.A., '87-313
Fine, R.J., '84-277
Finkbeiner, M.A., '85-116
Finkel, A.M., '87-341
Fischer, K.E., '80-91
Fisk, J.F., '85-130
Fitzpatrick, V.F., '84-191
Flatman, G.T., '85-442
Ford, K.L., '84-210, 230
Forney, D., '85-409
Forrester, R., '87-326
Fortin, R.L., '82-280
Francingues, N.R., '82-220
Franconeri, P., '87-89
Frank, J., '84-532
Frank, U., '80-165; '87-96, 110
Freed, J.R., '80-233
Freestone, F.J., '80-160. 208; '87-285
Freudenthal, H.G., '82-346
Friedman, P.M., '84-29, 49
Friedrich, W., '83-169
Funderburk, R. '84-195
Furman, C., '82-131
Furst, G.A., '85-93
Gallagher, G.A., '80-85
Galuzzi, P., '82-81
Garczynski, L., '84-521
Garlauskas, A.B., '83-63
Garnas, R.L., '84-39
Garrahan, K.G., '84-478
Gay, F.T., III, '82-414
Geil, M., '85-345
Geiselman, J.N., '83-266
Gemmill, D., '83-386; '84-371
Gensheimer, G.J., '84-306
Geraghty, J.J., '80-49
Geuder, D., '84-29
Ghassemi, M., '80-160
Ghuman, O.S., '84-90
Gianti, S.J., '84-200
Gibbs, L.M., '83-392
Gibson, S.C., '87-269
Gigliello, K., W457
Gilbert, J.M., '82-274
Gilbertson, M.A., '82-228
Gill, A., '84-131
Gillen, B.D., '82-27; '83-237
Gillespie, D.P., '80-125; '87-248
Gish, B.D., '84-122
Glaccum, R.A., '80-59; '87-84
Goggin, B., '87-411
Gold, J., '84-416
Gold, M.E., '87-387
Goldman, L.M., '84-277
Goldman. R.K., '87-215
Goldstein, P., '83-313
Goliber, P.. '80-71
Golob, R.S., '87-341
Golojuch, S.T., '85-423
Goltz, R.D., '82-262; '83-202; '84-489; '85-299
Goode, D.J., '83-161
Goodman, J., '85-419
Goodwin, B.E., '85-7
Gorton, J.C., Jr., '87-10; '84-435
Goss, L.B., '82-380
Gray, E.K., '85-406
GraybUl, L.. '83-275
Greber, J.S., '84^86; '85-387
Green, J., '87-223
Greiling, R.W., '84-535
Griffen, C.N., '85-53
Grube. W.E., Jr., '82-191, 249
Gruenfeld, M.. '80-165; '87-96; '82-36
Guerrero, P., '83-453
Gurba, P., '84-210, 230
Gurka, D.F., '82-45
Gushue, J.J., '87-359; '85-261
Haeberer, A.F.. '82-45
Hager, D.G., '82-259
Hagger, C., '87-45; '84-321; '85-7
Haji-Djafari, S., '83-231
Hale. F.D.. '83-195
Halepaska. J.C., '84-162
Hall, J.C., '84-313
Hallahan, F.M., '85-14
Hammond, J.W., '80-250; '87-294
Hanley, M.M., '82-111
Hansel, M.J., '83-253
Hanson. B., '82-141; '85-4
Hanson. C.R.. '84-189; '85-349
Hanson, J.B., '87-198; '84-493
Hardy, U.Z., '80-91
Harman, H.D., Jr., '82-97
Harrington, W.H., '80-107
Harris, D.J., '87-322
Harris, M.R., '83-253
Hartsfield, B., '82-295
Hass, H., '83-169
Hatayama, H.K., '87-149; '84-363
Hatch, N.N., Jr., '85-285
Hatheway, A.W., '85-331
Hawkins, C., '83-395
Hawley, K.A., '85-432
Hayes, E., '85-285
Hazaga, D., '84-404
486 AUTHOR INDEX
-------
Heare, S., '83-395
Heeb, M., '81-7
Hemsley, W.T., '80-141
Henderson, R.B., '84-135
Hendry, C.D., '85-314
Hennington, J.C., '83-21; '85-314
Hess, J.W., '83-108
Heyse, E., '85-234
Hijazi, N., '83-96
Hilker, D., '80-212
Hill, R., '52-233
Hill, R.D., '80-173
Hillenbrand, E., '82-357, 461
Hina, C.E., '55-63
Hines, J.M., '87-70; '55-349
Hinrichs, R., '50-71
Hirschhorn, J.S., '55-311
Hitchcock, S., '82-97
Hjersted, N.B., '80-255
Hoag, R.B., Jr., '55-202
Hodge, V., '84-62, 498
Holberger, R.L., '52-451
Holmes, R.F., '84-592
Holstein, B.C., '84-251
Hoogendoorn, D., '84-569
Hooper, M.W., '55-266
Hopkins, F., '50-255
Home, A., '57-393
Horton, K.A., '87-158
Housman, J., '80-25
Housman, J.J., Jr., '87-398
Houston, R.C., '50-224
Howe, R.W., '52-340
Hoylman, E.W., '82-100
Huffman, G.L., '84-207
Hughey, R.E., '55-58
Huizenga, H., '85-412
Hullinger, J.P., '55-136
Hunt, G.E., '80-202
Hunter, J.H., '85-326
Hupp, W.H., '87-30
Hwang, J.C., '87-317; '54-1
Hwang, S.T., '54-346
laccarino, T., '84-66
Ing, R., '84-239
Ingersoll, T.G., '57-405
Ingham, A.T., '55-429
Isaacson, L., '87-158
Isaacson, P.J., '85-130
Isbister, J.D., '82-209
Iskandar, I.K., '54-386
Jacobs, J.H., '52-165
Jacot, B.J., '55-76
James, S.C., '50-184; '57-171, 288; '52-70, 131;
'54-265; '55-234
Janis, J.R., '57-405; '82-354
Janisz, A.J., '82-52
Jankauskas, J.A., '85-209
Jarvis, C.E., '84-469
Jerrick, N.J., '55-389; '54-368
Jessberger, H.L., '55-345
Jhaveri, V., '55-242; '55-239
Johnson, D., '54-544
Johnson, M.G., '57-154
Johnson-Ballard, J., '87-30
Johnston, R.H., '85-145
Jones, A.K., '82-183, 448
Jones, B., '84-300; '85-412, 419
Jones, K.H., '52-63
Jones, R.D., '55-123, 346
Jones, S.G., '55-154
Jordan, B.H., '52-354
Jowett, J.R., '54-339
Jurbach, R., '84-66
Kaczmar, S.W., '54-221
Kadish, J., '52-458
Kaelin, J.J., '55-362
Kaplan, M., '82-131
Karon, J.M., '54-243
Kaschak, W.M., '82-124; '84-440; '55-281
Kastury, S., '55-189
Katz, S., '55-419
Kay, R.L., Jr., '54-232
Kay, W., '55-409
Keffer, W., '84-273
Keirn, M.A., '85-314
Keitz, E.L., '52-214
Kemerer, J.A., '54-427
Kennedy, S.M., '57-248
Kerfoot, H.B., '84-45
Kerfoot, W.B., '57-351
Khan, A.Q., '50-226
Kilpatrick, M.A., '50-30; '54-478
Kim, C.S., '50-212
Kimball, C.S., '55-68
King, J., '54-273; '55-243
Klinger, G.S., '85-128
Knowles, G.D., '85-346
Knox, R.C., '55-179
Koerner, R.M., '50-119; '57-165, 317; '52-12;
'55-175; '84-158
Koesters, E.W., '84-72
Kolsky, K., '84-300
Kopsick, D.A., '52-7
Kosin, Z., '55-221
Kosson, D.S., '55-217; '84-393
Koster, W.C., '50-141
Koutsandreas, J.D., '55-449
Kraus, D.L., '55-314
Kufs, C., '50-30; '52-146
Kugelman, I.J., '55-369
Kuykendall, R.G., '55-459
LaBar, D., '55-449
LaBrecque, D., '55-28
Lacy, W.J., '54-592
LaFornara, J.P., '87-110, 294; '55-128
LaGrega, M.D., '57-42
LaMarre, B.L., '52-291
Lambert, W.P., '84-412
Lamont, A., '54-16
Langner, G., '52-141
Lappala, E.G., '84-20
Larson, R.J., '50-180
Laswell, B.H., '85-136
Lataille, M., '52-57
Lavinder, S.R., '55-291
Lawrence, L.T., '54-481
Lawson, J.T., '52-474
LeClare, P.C., '85-398
Lederman, P.B., '80-250; '57-294
Lee, C.C., '82-214; '84-207
Lee, G.W., Jr., '85-123, 346
Lee, R.D., '55-157
Leighty, D.A., '85-79
Leis, W.M., '50-116
Lennon, G.P., '357
Leo, J., '52-268
Lewis, D.S., '84-382
Lewis, W.E., '84-427
Liddle, J.A., '54-243
Lincoln, D.R., '55-449
Linkenheil, R., '85-323
Lippe, J.C., '85-423
Lippitt, J.M., '82-311; '55-376
Lipsky, D., '52-81
LiVolski, J.A., Jr., '84-213
Lo, T.Y.R., '85-135
Lombard, R.A., '55-50
Longstreth, J., '85-412
Lord, A.E., Jr., '80-119, '87-165; '82-12; '85-
175; '54-158
Losche, R., '57-96
Lough, C.J., '52-228
Lounsbury, J., '54-498
Loven, C.G., '52-259
Lowe, G.W., '54-560
Lowrance, S.K., '55-1
Lucas, R.A., '52-187
Lueckel, E.B., '55-326
Lundy, D.A., '52-136
Luriney, P., '52-70
Lynch, D.R., '54-386
Lynch, E.R., '57-215
Lynch, J.W., '80-42; '85-323
Lysyj, I., '87-114; '55-446
Mack, J., '54-107
MacRoberts, P .B., '82-289
Magee, A.D., '55-209
Mahan, J.S., '52-136
Malone, P.O., '50-180; '52-220
Maloney, S.W., '85-456
Mandel, R.M., '80-21
Manko, J.M., '57-387
Mann, M.J., '85-374
Manuel, E.M., '85-249
Margolis, S., '85-403
Marshall, T.C., '84-261
Martin, W.F., '85-322; '84-248
Martin, W.J., '82-198
Maser, K.R., '55-362
Maslansky, S.P., '52-319
Maslia, M.L., '85-145
Mason, B.J., '84-94
Mason, R.J., '84-339
Massey, T.I., '80-250
Mateo, M., '55-413
Mathamel, M.S., '87-280
Matthews, R.T., '55-362
Maughan, A.D., '84-239
Mavraganis, P.J., '55-449
Mazzacca, A.J., '85-242; '85-239
McAneny, C.C., '85-331
McArdle, J., '54-486
McCloskey, M.H., '82-372
McClure, A.F., '84-452
McCord, A.T., '87-129
McEnery, C.L., '52-306
McGarry, F.J., '82-291
McGinnis, J.T., '82-380
McGlew, P.J., '84-150; '85-142
McGovern, D., '84-469
McKee, C.R., '54-162
McKown, G.L., '57-300, 306; '54-283
McLaughlin, D.B., '50-66
McLeod, D.S., '54-350
McLeod, R.S., '84-114
McMillan, K.S., '85-269
McMillion, L.G., '82-100
McNeill, J.D., '52-1
Meade, J.P., '84-407
Mehran, M., '55-94
Meier, E.P., '52-45
Melvold, R.W., '57-269
Menke, J.L., '80-147
Mercer, J.W., '82-159
Mernitz, S., '85-107
Messick, J.V., '87-263
Meyer, J., '50-275
Meyers, T.E., '50-180
Michelsen, D.L., '54-398; '55-291
Milbrath, L.W., '57-415
Miller, D.G., Jr., '52-107; '85-221
Miller, K.R., '85-136
Mitchell, F.L., '84-259; '55-406
AUTHOR INDEX 487
-------
Mittleman, A.L., '84-213
Monsees, M., '55-88
Montgomery, V.J., '83-8
Mooney, G.A., '84-35
Moore, S.F., '50-66
Morahan, T.J., '55-310
Moran, B.V., '55-17
Morey, R.M., 'SM58
Morgan, C.H., '50-202
Morgan, R.C., '82-366; '54-213; '85-396
Morin, J.O., '55-97
Morson, B.J., '84-535
Moslehi, J., '85-326
Mott, R.M., '80-269; '53-433
Mousa, J.J., '53-86
Moyer, E.E., '55-209
Moylan, C.A., '55-71
Muller, B.W., '82-268
Muller-Kirchenbauer, H., '53-169
Mullins, J.W., '55-442
Munoz, H., '54-416
Murphy, B.L., '52-331, 396; '83-13
Murphy, C.B., Jr., '83-195; '84-221
Murphy, J.R., '84-213
Murray, J.G., '85-464
Musser, D.T., '85-231
Mutch, R.D., Jr., '83-296
Myers, V.B., '82-295; '83-354
Myrick, J., '84-253
Nadeau, P.P., '82-124; '83-313
Nadeau, R.J., '85-128
Nagle, E., '83-370
Narang, R., '80-212
Naugle, D.F., '85-26
Nazar, A., '82-187; '84-356
Needham, L.L., '54-253
Neely, N.S., '80-125
Nelson, A.B., '57-52
Nelson, D.D., '85-32
Neumann, C., '82-350
Newman, J.R., '84-350
Nichols, F.D., '84-504
Nielson, M., '8/-374
Niemele, V.E., '52-437
Nimmons, M.J., '53-94
Nisbet, I.C.T., '52-406
Noel, M.R., '53-71
Noel, I.E., '53-266
Noland, J.W., '84-176, 203
Norman, W.R., '82-111; '55-261
North, B.E., '5/-103
Nyberg, P.C., '54-504
Nygaard, D.D., '53-79
Obaseki, S., '54-598
O'Dea, D., '53-331
O'Flaherty, P.M., '54-535
Ogg, R.N., '53-202, 358
Ohonba, E., '54-598
Oi, A.W., '57-122
O'Keefe, P., '50-212
Okeke, A.C., '55-182
Olsen, R., '55-107
Oma, K.H., '54-191
O'Malley, R., '55-58
Openshaw, L-A, '53-326
Opitz, B.E., '52-198
Orr, J.R., '85-349
Osborn, J., '53-43
Osheka, J.W., '80-184
O'Toole, M.M., '55-116
Ounanian, D.W., '83-270
Owens, D.W., '80-212
Page, R.A., '84-594
Paige, S.F., '80-30, 202
Palombo, D.A., '82-165
Pajak, A.P., '80-184; '57-288
Parks, O.A., '83-280
Parker, F.L., '87-313
Parker, J.C., '54-213
Parker, W.R., '54-72
Parratt, R.S., '83-195
Parrish, C.S., '85-1
Parry, G.D.R., '82-448; '84-588
Partridge, L.J., '54-290; '55-319
Partymiller, K., '54-213
Paschal, D., '55-409
Paschke, R.A., '55-147
Patnode, T., '55-323
Pearce, R.B., '57-255; '53-320
Pease. R.W., Jr., '50-147; '57-171, 198
Pennington, D., '85-253
Peters, J.A., '87-123
Peters, W.R., '82-31
Peterson, J.M., '85-199
Phillips, J.W., '8/-206
Pierson, T., '84-176
Pintenich, J.L., '87-70
Plourd, K.P., '85-396
Plumb, R.H., '84-45
Ponder, T.C., '85-387
Possidento, M., '50-25
Possin, B.N., '53-114
Powell, D.H., '53-86
Predpall, D.F., '54-16
Preston, J.E., '84-39
Price, D.E., '84-478
Price, D.R., '52-94
Priznar, F.J., '55-1, 74
Proko, K., '55-11
Prothero, T.G., '54-248
Prybyla, D.A., '55-468
Quan, W., '87-380
Quinlivan, S., '80-160
Quimby, J.M., '82-36
Quinn, K.J., '84-170; '85-157
Quintrell, W.N., '85-36
Rademacher, J .M., '84-189; '85-349
Rams, J.M., '87-21
Ramsey. W.L., '80-259; '87-212
Ransom, M., '80-275
Rappaport, A., '57-411
Rebis, E.N., '53-209
Reifsnyder, R.H., '82-237
Reiter, G.A., '80-21
Remeta, D.P., '80-165; '81-96
Repa, E., '82-146; '85-164
Reverand, J.M., '84-162
Rice, E.D.. '85-84
Rice, J.M., '55-182
Rice, R.G., '54-600
Richards, A.. '50-212
Richardson, S., '84-1
Rick, J., '84-469
Ridosh, M.H., '84-427; '85-243
Rikleen, L.S., '82-470; '85-275
Ritthaler, W.E., '82-254
Riner, S.D., '82-228
Rishel, H.L., '87-248
Rizzo, J., '52-17
Rizzo, W.J., Jr., '55-209
Robbins, J.C., '53-431
Roberts, B.R., '53-135
Rockas, E., '85-11
Rodricks, J.V., '83-401
Rogers, W., '84-16
Rogoshewski, P.J., '80-202; '52-131, 146;
'54-62
Romanow, S., '55-255
Roos, K.S., '53-285
Rosasco. P.V.. '54-103
Rosbury, K.D., '54-265
Rosebrook, D.D., '54-326
Rosenkranz, W., '87-7
Ross, D., '84-239
Rothman, D.W., '54-435
Rothman, T., '52-363
Roy, A.J., '53-209
Royer, M.D., '87-269
Ruda, F.D., '84-393
Rulkens, W.H., '52-442; '84-576
Ryan, F.B., '87-10
Ryan, M.J., '85-29
Ryan, R.M., '85-125
Ryckman, M.D., '84-420
Sadat, M.M., '83-301, 413
Salvesen, R.H., '54-11
Sanders, D.E., '82^61
Sandness, G.A.. '57-300; '83-68
Sandza, W.F., '85-255
Sanford, J.A., '84-435
Sanning, D.E., '87-201; '82-118, 386
Sappington, D., '85-452
Sarno. D.J., '55-234
Schafer, P.E., '55-192
Schalla, R., '83-117; '84-283
Schauf, F.J., '80-125
Scheppers, D.L., '54-544
Schilling, R.. '84-239
Schlossnagle, G.W., '83-5, 304
Schmidt, C.E., '82-334; '83-293
Schnabel, G.A., '80-107
Schneider, P., '80-282
Schneider, R., '50-71
Schnobrich, D.M., '85-147
Schoenberger, R.J.. '82-156
Schofield, W.R., '84-382
Scholze. R.J., Jr., '85-456
Schomaker, N.B., '80-173; '82-233
Schuller, R.M.. '82-94
Schultz, D.W., '82-244
Schweitzer, G.E., '87-238; '82-399
Scofield, P.A., '83-285
Scott, J.C.. '87-255; '83-320
Scott, M., '82-311; '83-376
Scrudato, R.J., '80-71
Seanor. A.M., '87-143
Sebba, F , '84-398
Segal, H.L., '85-50
Selig, E.I., '82-458; '83-437
Sepesi, J.A., '85-423, 438
Sevee, J.E., '82-280
Sewell, G.H.. '52-76
Seymour, R.A., '52-107
Shafer, R.A., '54-465
Sharkey, M.E., '54-525
Sharma, O.K., '57-185
Shaw, L.G., '57-415
Sheedy, K.A.. '50-116
Shen, T.T., '52-70, 76; '54-68
Sheridan, D.B., '54-374
Sherman, J.S., '82-372
Sherwood, D.R., '82-198
Shih, C.S., '87-230; '82-390, 408; '83-405
Shiver, R.L., '85-80
Shroads, A.L., '83-86
Shuckrow, A.J., '80-184; '87-288
Shultz, D.W., '82-31
Sibold, L.P., '85-74
Siebenberg, S., '84-546
Silbermann, P.T., '80-192
Silcox, M.F., '53-8
Silka, L.R., '80-45; '82-159
488 AUTHOR INDEX
-------
Sills, M.A., '80-192
Simcoe, B., '57-21
Simmons, M.A., '54-85
Sims, R.C., '83-226
Singer, G.L., '54-378
Singh, J., '54-81
Singh, R., '83-141
Sirota, E.B., "53-94
Siscanaw, R., '52-57
Sisk, W.E., '54-203, 412
Skalski, J.R., '54-85
Skoglund, T.W., '55-147
Slack, J., '50-212
Slater, C.S., '52-203
Sloan, A., Ill, '55-438
Smart, R.F., '54-509
Smiley, D., '54-66
Smith, C., '54-546
Smith, E.T., '50-8
Smith, J.S., '54-53
Smith, L.A., '55-396
Smith, M.A., '52-431; '54-549
Smith, R., '50-212
Smith, R.L., '55-231
Snow, M., '55-67
Snyder, A.J., '57-359
Snyder, M., '50-255
Sokal, D., '54-239
Solyom, P., '53-342
Sosebee, J.B., '54-350
Sovinee, B., '55-58
Spatarella, J.J., '54-440
Spear, R., '57-89
Spencer, R.W., '52-237
Spittler, T.M., '57-122; '52-40, 57; '53-100,
105; '55-93
Spooner, P.A., '50-30, 202; '52-191; '55-214,
234
Springer, C., '52-70
Srivastava, V.K., '53-231
Staible, T., '55-107
Stammler, M., '53-68
Stanfill, D.F., III, '55-269
Stanford, R., '57-198; '54-498; '55-275
Stankunas, A.F., '52-326
Stanley, E.G., '53-1
Starr, R.C., '50-53
St. Clair, A.E., '52-372
Steele, J.R., '54-269
Steelman, B.L., '55-432
Stehr, P.S., '54-287
Steimle, R.R., '57-212
Stein, G.F., '54-287
Steinberg, K.K., '54-253
Stephens, R.D., '50-15; '52-428; '55-102
Stief, K., '52-434; '54-565
Stokely, P.M., '54-6
Stoller, P.J., '50-239; '57-198
Stone, T., '55-128
Stone, W.L., '57-188
Stoner, R., '54-66
Strandbergh, D., '54-81
Strattan, L.W., '57-103
Strauss, J.B., '57-136
Strenge, D.L., '55-432
Strickfaden, M.E., '55-7
Strong, T.M., '55-473
Stroud, F.B., '52-274
Struzziery, J.J., '50-192
Sullivan, D.A., '57-136
Sullivan, J.H., '53-37
Sullivan, J.M., Jr., '54-386
Swaroop, A., '54-90
Swatek, M.A., '55-255
Swenson, G.A., III, '53-123
Swibas, C.M., '54-39
Tackett, K.M., '57-123
Tafuri, A.N., '57-188; '52-169; '54-407
Tanzer, M.S., '57-10
Tapscott, G., '52-420
Tarlton, S.F., '54-445
Tate, C.L., Jr., '54-232
Taylor, B., '53-304
Teets, R.W., '53-310
Teller, J., '54-517
Tewhey, J.D., '52-280; '54-452
Theisen, H.M., '52-285
Thibodeaux, L.J., '52-270
Thomas, A., '54-176
Thomas, C.M., '55-112
Thomas, G.A., '50-226
Thomas, I.E., Jr., '54-150; '55-142
Thomas, J.M., '54-85
Thomas, S.R., '55-476
Thompson, G.M., '54-20
Thompson, S.N., '53-331
Thompson, W.E., '54-469; '55-387
Thorsen, J.W., '57-42, 259; '52-156
Threlfall, D., 'SO-131; '52-187
Tifft, B.C., Jr., '54-221
Tillinghast, V., '55-93
Timmerman, C.L., '54-191
Tinto, T., '55-243
Titus, S.E., '57-177
Townsend, R.W., '52-67
Trees, D.P., '54-49
Tremblay, J.W., '53-423
Triegel, E.K., '53-270
Troxler, W.L., '55-460
Truett, J.B., '52-451
Tucker, W.A., '54-306
Tuor, N.R., '53-389; '54-368
Turner, J.R., '53-17
Turnham, B., '55-423
Turoff, B., '50-282
Turpin, R.D., '57-110, 277; '53-82; '54-81, 273
Tusa, W.K., '57-2; '52-27
Twedell, A.M., '50-233
Twedell, D.B., '50-30, 202
Tyagi, S., '52-12
Tyburski, T.E., '55-396
Unites, D.F., '50-25; '57-398; '53-13
Unterberg, W., '57-188
Urban, M.J., '54-53
Urban, N.W., '52-414; '53-5, 304
Vais, C., '54-427
Vanderlaan, G.A., '57-348; '52-321; '53-366
Vandervort, R., '57-263
Van Ee, J.J., '53-28
Van Gemert, W.J. Th, '52-442
Van Slyke, D., '53-442
Viste, D.R., '54-217
Vogel, G.A., '52-214
Voorhees, M.L., '55-182
Vora, K.H., '54-81
Vrable, D.L., '55-378
Wagner, J., '54-97
Wagner, K., '52-169; '53-226; '54-62; '55-221
Walker, K.D., '54-321
Wallace, L.P., '53-322
Wallace, J.R., '53-358
Waller, M.J., '53-147
Wallis, D.A., '54-398; '55-291
Walsh, J., '52-311
Walsh, J.F., '52-63
Walsh, J.J., '50-125; '57-248; '53-376
Walther, E.G., '53-28
Wardell, J., '57-374
Wasser, M.B., '55-307
Watson, K.S., '55-307
Way, S.C., '54-162
Weaver, R.E.C., '55-464
Webb, K., '54-287
Weber, D.D., '53-28
Weiner, P.H., '57-37
Weiss, C., '54-546
Weist, F.C., '53-175
Welks, K.E., '50-147
Werner, J.D., '53-370
Wetzel, R.S., '50-30, 202; '52-169, 191; '55-234
Wheatcraft, S.W., '53-108
Whelan, G., '55-432
White, L.A., '55-281
White, M., '50-275
White, R.M., '52-91
Whitlock, S.A., '53-86
Whittaker, K.F., '52-262
Wiggins, K.E., '55-314
Wilder, I., '50-173; '52-233
Wiley, J.B., '55-58
Wilkinson, R.R., '50-255
Williamson, S.J., '54-77
Wilson, D.C., '50-8
Wilson, L.G., '52-100
Wine, J., '53-428
Winklehaus, C., '55-423
Wirth, P.K., '54-141
Wise, K.T., '54-330
Witherow, W.E., '54-122
Witmer, K.A., '55-357
Wittman, S.G., '55-157
Woelfel, G.C., '55-192
Wolbach, C.D., '53-54
Wolf, F., '53-43
Wolfe, S.P., '55-88
Wong, J., '57-374
Woodhouse, D., '55-374
Worden, M.H., '54-273
Worst, N.R., '54-374
Wright, A.P., '50-42
Wuslich, M.G., '52-224
Wyeth, R.K., '57-107
Wyman, J., '53-395
Yaffe, H.J., '50-239
Yang, E.J., '57-393; '53-370; '54-335
Yaohua, Z., '54-604
Yezzi, J.J., Jr., '57-285
Young, L., '50-275
Young, R.A., '57-52
Youzhi, G., '54-604
Yu, K., '50-160
Yuhr, L., '55-112
Zamuda, C., '55-412, 419
Ziegenfus, L.M., '54-521
Ziegler, F.G., '57-70; '55-349
Zimmerman, P.M., '54-326
Zuras, A.D., '55-1
AUTHOR INDEX 489
-------
Subject Index
This Subject Index contains subjects presented in 1980-1985 only.
Above Ground Closure, '83-215
Acidic Waste Site, '85-326
Activated Carbon, '81-314; '82-259, 262; '83-
209, 248, 253, 342
Adsorption, '54-393
Advanced Technologies, '84-412
Agricultural Fire Residue, '84-420
Air Modeling, '52-331; '84-66
Air Monitoring, '82-61, 268, 299, 306, 331;
'55-82 85
Ambient, '8/-280; '55-293; '85-125
Cleanup Site, '54-72
Emissions, '82-70
Nitrogen Compounds, '85-100
Real Time, '85-98
Sampling Techniques, '82-334
Two Stage Tube, '85-85; '84-81
Air Photos, '50-116; '55-116
Air Quality, '82-63
Assessment, '82-76
Air Stripping, '85-209, 313, 354; '84-170
Emissions Control, '84-176
Analysis, '82-45
Drum Samples, '84-39
Metals, '85-79
Portable Instruments, '82-36, 40, 57
Pyrographic, '87-114
Quality Control, '54-29
Screening, '85-86; '85-97
Site Data Base, '84-49
Spectrometer, '85-291
Arizona
TCE Contamination, '82-424
Arsenic Waste, '84-469; '85^*09
Asbestos, '85-21
ASCE, '87-2
Assessment, '82-17, 27; '85-37
Areal Photography, '85-116
Biological, '82-52
Cold Weather, '82-254
Endangerment, '84-213, 226
Health Effects, '54-253
Health Risk, '84-230, 261
Management, '81-348, 351
Mathematical Modeling, '81-306, 313
Mercury Contamination, '82-81
Methods, '87-79
Pesticide Plant, '82-7
Site, '55-209
Auditing, '87-398
Baird & McGuire Site, '85-261
Barriers, '82-249
Bentonite, '52-191
Cement, '54-126
Gelatinous, '82-198
Leachate Compatibility, '84-131
Bedrock Aquifers, '85-142
Contaminant Movement, '82-111; '85-202
Bench Scale Study, '87-288
Bench Scale Testing, '80-184
Beneficial Use, '84-560
Bentonite-Cement Mixtures
Durability, '85-345
Bentonite-Soil Mixture Resistance, '54-131
Bentonite-Soil Slurry Walls. '85-357, 369
Berlin & Farro, '87-205
Bid Protests, '84-520
Bidding Cleanup Contracts, '84-509
Biodegradation, '82-203; '84-393; '85-234
Bioindicators, '87-185
Biological Monitoring, '87-238
Bioreclamation, '85-239
Block Displacement Method, '82-249
Bottom Barrier, '54-135
Bridgeport Rental and Oil Services Site, '85-299
Bromine
Organic, '82-442
Building Decontamination, '84-486
Buried Drums
Sensing, '80-239
California
Superfund Program, '82-428
Ranking System, '55-429
Callahan Site, '52-254
Capping, '85-123, 296
Cost, '85-370
Carcinogens, '84-11
Cell Model, '85-182
Cement/Asphalt Emulsion, '54-131
CERCLA Remedies, '85-4
Change Orders, '84-521
Chemical
Analysis
Rapid, '50-165
Control, '57-341; '84-416
Oxidation, '85-253
Plant
Emergency Removal, '85-338
Specific Parameters, '85-412
Children
Arsenic Exposure, '85-409
China, '84-604
Chlorinated Hydrocarbons
Groundwater Monitoring, '82-1
Chromium Sludge, '80-259
Circulating Bed Combustor, '85-378
Citizen Information Committees, '85-473
Claims, '84-521
Clay
Leachate Interaction, '85-154
Organic Leachate Effect, '87-223
Cleanup, '80-147, 257
Air Monitoring, '84-72
Asbestos, '85-21
Assessment Role, '85-389; '55-116
BT-KEMI Dumpsite. '85-342
Case Studies, '85-395; '84-440
Coal Tar, '85-331
Cold Weather, '82-254
Community Relations, '85-468
Contract Bids, '84-509
Cost Allocation, '84-326
Criteria, '85-301
Delays, '85-320
Drum Site, '85-354
Dual Purpose, '85-352
Enforcement, '84-478
Extent, '85-433
Federal, '85-7
Federal/State Cooperation, '85-50
Forced, '87-255
Generator, '85-7
Gilson Site Proposal, '82-289
Hardin County Brickyard, '82-274
Level, '85-398
Liability Due to Failure, '85-442
Long-Term Effectiveness, '82-434
Management, '85-370
Pacific Island, '84-427
PCB, '52-156, 284
PiciUo Farm, '82-268
Public Information Needs, '84-368
Radioactive Mine Tailings, '84-504
Radium Processing Residues, '84-445
Reserve Fund, '55-58
Rocky Mountain Arsenal, '85-36
Staged Approach, '82-262
State-of-the-Art Technology, '85-285
Toxic Wastes, '85-311
Cleve Reber Site, '85-136
Closure, '87-259
Copper Residue Disposal Site, '87-70
Creosote Impoundment, '85-323
Impoundment, '55-195
Industrial Site, '54-277
Inplace, '54-185
Closure/Post-Closure
Illinois Perspective, '85-459
CMA, '87-1
Coal Mine Groundwater Cleanup, '84-356
Coal Tar Cleanup, '85-331; '84-11
Community Coordinator, '57-411
Community Relations
(See Also Public Participation)
'57-405, 415; '52-354; '54-378
Activities, '84-371
Health Concerns, '82-321
Program, '85-386, 389
Compatibility Testing, '87-110
490 SUBJECT INDEX
-------
Composting
Soils, '52-209
Computer Risk Analysis, '84-300
Connecticut
Risk Evaluation, '50-25
Containment System Design, '52-175
Contaminated Land, '54-549
Contaminated Soil, '55-226, 231
Cleanup, '55-354
Contamination
Mapping, '55-71; '54-85
Contingency Fund, '50-21
Contingency Plan
Massachusetts, '55-420
Remedial Sites, '54-489
Contracts
REM/FIT, '55-313
Cooperative Agreement, '54-103; '55-53
Copper Smelter
Arsenic Wastes, '55-409
Cost, '50-202; '57-248; '55-209
Above Ground Waste Storage, '52-228
Air Stripping, '55-313
CERCLA Financed, '55-395
Cleanup, '52-262; '55-296, 366, 370;
'54-341
Cleanup Allocation Model, '54-326
Cleanup Level, '55-398
Computer Models, '55-362
Cover, '52-187
Effective Screening, '55-93
Effectiveness Evaluation, '52-372; '54-290
Estimates, '50-202; '54-330, 335
Ground Freezing, '54-386
Groundwater Treatment, '55-248, 358
Health and Safety Impact, '55-376
Leachate Collection, '55-237
Leachate Monitoring, '52-97
Management, '54-339
Minimization, '57-84
Recovery, '54-313
Recovery Documentation, '52-366
Remedial, '52-118
Savings via Negotiation, '52-377
Treatment System, '57-294
Water Recovery System, '52-136
Coventry, RI, '50-239
Covers
(See Also Caps)
'52-183, 187, 448; '54-588
Design and Construction, '55-331
Pesticide Disposal Site, '55-349
Creosote Impoundment, '55-323
Criticism, '54-532
Cutoff Wall, '55-123, 296
Chemically Resistant, '55-169, 179, 191
Cost, '55-362
Cyanides, '54-598, 600
Damage
Cost Recovery, '57-393
Data Bases, '55-304; '54-49, 59
Decision-Making, '57-230
Decision Tree Analysis, '52-408
Decontaminating Buildings, '54-486
Decontamination, '50-226
Waterway, '55-21
Degradation
TNT Sludge, '55-270
VOCs, '54-217
Denney Farm, '57-326
Department of Defense Program, '52-128
TNT Cleanup, '55-314
Department of Energy, '55-29
Design
Mathematical Modeling, '57-306
Preliminary, '50-202
Detection
Buried Drums, '54-158
Detonation, '54-200
Detoxification, '50-192; '54-382
Fire Residues, '54-420
DIMP, '57-374
Dioxin, '57-322, 326; '55-405; '54-287; '55-261
Dispersion of Coefficients, '55-135
Disposal, '57-329
Above Ground, '55-275
Commercial Criteria, '52-224
Computer Cost Model, '55-362
Liability, '55-431
Mine, '55-387
Salt Cavities, '55-266
Shock Sensitive Chemicals, '54-200
Documentation
Cost Recovery, '52-366
DOD
Hazardous Materials Technical Center,
•52-363
IRP, '55-26
Site Cleanup, '55-326
Downhole Sensing, '55-108
Drain System, '55-237
Drinking Water Contamination, '54-600
Drums, '52-254
Analysis, '54-39
Buried, '52-12; '54-158
Handling, '52-169
Site Cleanup, '55-354
Dust Control, '54-265
Electric Reactor, '54-382
Electromagnetic
Induction, '55-28, 68
Resistivity, '52-1
Survey, '50-59; '52-12
Waves, '50-119
Emergency
Planning, '54-248
Removal, '55-338
Emissions
Monitoring, '55-293
Rates, '54-68
Endangerment Assessments, '54-213; '55-396,
423, 438
Enforcement, '84-544; '85-21
Cleanup, '54-478
Endangerment Assessments, '54-213;
'85-396
Information Management, '55-11
Environmental
Concerns, '54-592
Impact, '57-177
Risk Analysis, '52-380
Epidemiologic Study, '84-287
Excavation, '82-331
Exhumation, '82-150
Explosives
Contaminated Soils Incineration, '84-203
Waste Disposal Sites, '84-141
Exposure
Children, '84-239
Response Analysis, '82-386
Extraction, '84-576
Fast-Tracked Hydrogeological Study, '85-136
Feasibility Study
Arsenic Waste, '84-469
Federal Cleanup, '85-7
Federal Facility Coordinator, '85-32
Federal/State Cooperation, '52-420; '85-50
Field
Identification, '85-88
Sampling, '54-85, 94
Fire, '57-341; '52-299
First Responder Training, '55-71
FIT
Contracts, '55-313
Health and Safety, '50-85
Floating Covers, '54-406
Florida's Remedial Activities, '52-295
Fort Miller, '57-215
Foundry Wastewater, '54-598
Fractured Bedrock, '84-150
Fugitive
Dust Control, '54-265
Hydrocarbon Emission Monitoring,
'57-123
Gas Chromatograph, '52-57, 58; '55-76
Portable, '52-36; '85-105
GC/MS, '52-57
Gases
Unknown, '54-416
Gasoline, '55-269
Generator Cleanup, '85-7
Geohydrology, '85-117
Geophysical, '55-68, 71
Investigation, '54-481
Methods, '52-17
Monitoring, '55-28
Survey, '57-300
Techniques, '55-130
Geophysics, '57-84; '52-91
Geostatistical Methods, '55-107
Geotechnology
Containment System, '52-175
Property Testing, '55-249
Techniques, '85-130
Germany, '84-565, 600
Gilson Road Site, '82-291
Ground Freezing, '54-386
Ground Penetrating Radar, '50-59, 116, 239;
'57-158, 300; '55-68
Groundwater
Alternatives to Pumping, '52-146
Biodegradation, '55-234
Cleanup, '52-118, 159; '55-354; '84-176
Cyanide Contamination, '84-600
Containment, '82-259; '85-169
Containment Movement, '82-111; '55-147
Contamination, '57-329, 359; '52-280;
'55-43, 358; '54-103, 141, 145, 162,
170, 336; '55-43, 157, 261
Detection, '84-20
Liabilities, '55-437
Mapping, '55-71
Potential, '50-45
Flow System, '55-114, 117
Halocarbon Removal, '55-456
Hydraulic Evaluation, '55-123
Investigation, '50-78; '84-1, 107
In Situ Biodegradation, '85-239
Mathematical Modeling, '87-306
Metal Finishing Contamination, '85-346
Microbial Treatment, '85-242
Migration, '80-71; '54-150, 210
Prevention, '85-179, 191; '54-114
Mobility, '54-210
Modeling, '52-118; '55-135, 140, 145;
'54-145
Monitoring, '80-53; '82-17, 165
Evaluation, '85-84
Interpretation, '82-86
Long-Term, '85-112
Statistics, '84-346
Plume Definition, '85-128
Pollution Source, '87-317
Post-Closure Monitoring, '85-446
SUBJECT INDEX 491
-------
Protection, '50-131; '84-565
Recovery Cost, '52-136
Recovery Design, '52-136
Remedial Plans, '53-130
Research Needs, '55-449
Restoration, '52-94; '84-162
Sampling, '8M43, 149
TCE Contamination, '52-424
Treatability, '57-288
Treatment, '50-184; '52-259; '83-246, 253
VOC Biodegradation, '54-217
Grout, '53-169, 175
Chemistry, '52-220
Grouting, '52-451
Silicates, '52-237
Halocarbon Removal, '55-456
Halogen
Combustion Thermodynamics, '55-460
Harrisburg International Airport, '55-50
Hazards
Degree, '81-1
Potential, '50-30
Ranking, '57-188
Prioritizing, '57-52
Scoring, '55-74
System, '57-14; '52-396
U.S. Navy Sites, '53-326
Unknown, 'S/-371
vs. Risk, '54-221
Hazardous Materials
Identification, '55-88
Storage
Spills, '52-357
Technical Center, '52-363
Hazardous Waste
Emergencies
Information Sources, '54-59
Management Facility Siting, '54-517
Policies, '54-546
Site Reuse, '54-363
Health and Safety (See also Safety)
Assessments, '54-261; '55-423
Community Concerns, '52-321
Cost Impact, '53-376
Guidelines, '53-322
Hazards, '50-233
Plan, '53-285
Program, '50-85,91. 107
Health Risk Assessment, '54-230, 253
Heart Stress Monitoring, '54-273
Heavy Metals
Impoundment Closure, '53-195
High-Pressure Liquid Chromatography, '53-86
Hyde Park, '55-307
Hydrocarbons, '55-269
Leaks, '52-107
Hydrogeologic
Data, '54-6
Evaluation, '50-49
Fast-Track, '55-136
Landfill. '55-182
Investigation, '57-45, 359; '53-346
Identification, '53-63
Hazardous Material, '55-88
Reactivity, '53-54
Illinois
Closure/Post Closure, '53-459
Immobilization, '52-220
Impact Assessment, '57-70
Impoundment, '50-45
Closure, '53-195; '54-185; '55-323
Leaks, '53-147
Membrane Retrofit, '52-244
Sampling, '55-80
Incineration, '52-214
Explosives Contaminated Soils, '54-203
Halogens, '85-460
Mobile, '50-208; '57-285
Performance Assessments, '85-464
Research, '54-207
Sea, '50-224
Inductive Coupled Plasma Spectrometer, '53-
79
Information
Committees, '55-473
Management, '55-11
Infrared Incinerator, '55-383
In Situ
Biodegradation, '55-234, 239, 291
Chemical Treatment, '85-253
Pesticide Treatment, '85-243
Solidification/Fixation, '85-231
Stabilization, '85-152
Treatment, '54-398; '55-221
Vitrification.m '54-195
Installation Restoration Program
McClellan AFB, '54-511; '55-26
Insurance, '52-464
Interagency Management Plans, '50-42
Investigation
Hydrogeologic, '52-280
Kriging, '50-66
Laboratory
Management, '57-96
Regulated Access, '57-103
La Bounty Site, '52-118
Lagoons, '57-129; '52-262
Floating Cover, '54-406
Landfill
Closure, '50-255
Future Problems, '50-220
Risk, '55-393
Leachate
Clay Interaction, '53-154
Collection, '53-237; '55-192
Control, '54-114
Effects on Clay, '57-223
Generation Minimization, '50-135, 141
Migration, '52-437
Minimization, '57-201
Modeling, '53-135; '84-97; '85-189
Monitoring Cost, '82-97
Plume Management, '85-164
Treatment, '80-141; '82-203,437; '53-
202, 217; ;84-393; '85-192
Lead, '84-239; '85-442
Leak Detection, '83-94, 147; '55-362
Legal Aspects
Extent of Cleanup, '83-433
Legislation
Model Siting Law, '80-1
Liability, '82-458 . 461, 464, 474
Corporate, '80-262
Disposal, '83-431
Generator, '87-387
Groundwater Contamination, "53-437
Inactive Sites, '50-269
Superfund Cleanup Failure, '53-442
Trust Fund, '53-453
Liner
Breakthrough, '53-161
Flexible, '54-122
Leak Detection, '55-362
Leak Location, '52-31
Synthetic Membrane, '53-185
Love Canal, '50-212, 220; '57-475; '52-159, 399
Low Occurrence Compounds, '55-130
Magnetrometry, '50-59, 116; '57-300, '52-12;
•83-68
Management Plans
New Jersey, '53-413
Managing Conflict, '54-374
Mass Selective Detector, '55-102
Massachusetts Contingency Plan, '53-420;
'85-67
McClellan AFB, '85-43
Medical Surveillance, '84-251, 259
Mercury, '52-81
Metals, '52-183
Analysis, '53-79
Detection, '50-239
Detector, '50-59; '57-300; '82-12
Finishing, '83-346
Screening. '85-93
Microbial Degradation, '83-217, 231, 242
Microdispersion, '84-398; '85-291
Migration, '54-588
Cut-Off, '52-191
Prevention, '52-448
Mine
Disposal, '55-387
Mine/Mill Tailings, '55-107
Sites, '53-13
Tailings Cleanup, '84-504
Mobile
Incinerator, '85-378, 382
Laboratory, '80-165; '54-45
MS/MS, '84-53
Modeling
Cell, '85-182
Groundwater Treatment, '53-248
Leachate Migration, '52-437; '55-189
Management Options, '53-362
Remedial Action. '53-135
Site Assessment, '57-306
Monitoring
Ambient Air. '81-112. 136
Wells
Installation, '57-89
Location, '87-63
MS/MS Mobile System, '54-53
Multi-Site/Multi-Activity Agreements, '55-53
National
Contract Laboratory Program, '54-29
Priority List (NPL). '85-1
Mining Sites, '83-13
Resource Damage, '87-393
Response, '87-5
NATO/CCMS Study, '54-549
Natural Resources Restoration/Reclamation.
'54-350
Negotiated Remedial Program, '54-525
Negotiating, '52-377, 470
Netherlands, '54-569
Neutralization, '53-63
New Jersey
Cleanup Plans, '53-413
DEP, '55-48
Reserve Fund, '55-58
New York City, '54-546
No-Action Alternative, '55-449
Non-Destructive Testing Methods, '82-12;
'54-158
North Hollywood Site, '54-452
Occupational Health Programs, '54-251, 259
Odor, '52-326; '53-98
Oil Recovery, '85-374
Old Hardin County Brickyard, '82-274
Olmsted AFB, '85-50
OMC Site, '54-449
On-Site Leachate Renovation, '54-393
492 SUBJECT INDEX
-------
Organics
Emissions, '52-70; '84-176
Sludge Stabilization, '54-189
Solvents Permeability, '84-131
Vapor
Analysis, '55-98
Field Screening, '55-76
Leak Detection, '55-94
Personnel Protection, '57-277
Wastes
Characterization, '54-35
Ott/Story, '57-288
Pacific Island Removal, '54-427
Parametric Analysis, '57-313
PCBs, '57-215; '52-156, 284; '55-21, 326, 366,
370; '54-243, 277, 449
Field Measurement, '55-105
Pennsylvania Program, '57-42
Permeability Coefficient Measurement, '54-584
Personnel Protection Levels, '57-277
Pesticides, '52-7; '55-255, 349
In Situ Treatment, '55-243
Petro Processors Site, '54-478
Petroleum Contamination, '54-600
Photographic Interpretive Center, '54-6
Physical Chemical Data Use, '54-210
Picillo Farm Site, '52-268
Pilot Plant, '57-374
PIRS, '52-357
Pittston, PA, '50-250
Plant Bioindicators, '57-185
Pollution Abatement Site, '54-435
Polyaromatic Hydrocarbons, '54-11
Post-Closure
Care, '57-259
Failure, "55-453
Groundwater Monitoring, '55-446
Monitoring, '52-187
Monitoring Research, '55-449
Potentially Responsible Party (PRP), '55-275
POTW
Leachate Treatment, '55-202
Price Landfill
Remedial Action, '55-358
Prioritization (See also Hazard Ranking), '57-
188
Probabilistic Spatial Contouring, '55-442
Public
Awareness, '55-383
Health, '54-232; '55-438
Information Program, '50-282; '54-3;
'55-473
Needs, '54-368
Involvement, '55-476
Participation (See Also Community
Relations) '52-340, 346, 350; '55-383
Failures, '55-392
Policy
Cleanup Level, '55-398
Relations, '55-468
Pulsed Radio Frequency, '57-165
galley 6 b:
Quality
Assurance Audits, '54-94
Control, '52-45; '54-29
Radar Mapping, '55-269
Radioactive
Mine Tailings, '54-504
Site Assessment, '55-432
Wastes, '57-206
Radium Processing Residues, '54-445
Radon
Contamination, '54-457
Gas, '52-198
RAMP, '52-124
Love Canal, '52-159
Ranking System, '57-14; '55-429
RCRA
Requirements, '55-4
Section 3012, '54-535, 544
RDX, '52-209
Reactivity
Identification, '55-54
Real Estate
Hazardous Waste Implications, '52-474
Reclamation
Chromium Sludge, '50-259
Records Management System, '57-30
Recovery
Organics, '54-145
Regional Response Team, '50-6; '52-274
REM Contracts, '55-313
Remedial
Action, '52-289
Alternatives, '54-35, 277, 290, 306,
321
Risk Assessment, '55-319
Case Studies, '52-131
Contingency Plans, '54-489
Costs, '54-335, 341
Cost Management, '54-339
Decision-Making, '54-66
Design, '50-202
Pesticides, '55-255
Florida's Site, '52-295
Groundwater, '54-565
Investigation, '54-435
Guidance, '54-498
Lessons, '54-465
Negotiated, '54-525
Netherlands, '54-569
North Hollywood Site, '54-452
Options, '50-131
Planning, '55-281
Priority System, '55-432
Progress Status, '50-125
Public Involvement, '55-476
Screening and Evaluation, '54-62
Selection, '54-493
Technologies, '55-285
Construction
Safety Plans, '55-280
Cost Estimation Model, '54-330
Design
Groundwater, '55-123; '54-109, 356
Model-Based Methodology, '55-135
OMC Site, '54-449
Thamesmead, '54-560
Projects
Corps of Engineers, '55-17
Response
Role of U.S. Army, '52-414
Technologies
Screening and Evaluation, '54-62
Remediation
Innovative Approach, '55-307
Remote Sensing, '50-59, 239; '57-84, 158, 165,
171
Research
Post-Closure Monitoring, '55-449
U.S. EPA Program, '50-173
Reserve Fund, '55-58
Resistivity, '50-239; '57-158; '52-31; '55-28
Resource Recovery, '57-380
Response
Model, '57-198
Procedures, '50-111
Restoration
Swansea Valley, '54-553
Reusing Hazardous Waste Sites, '55-363
Reverse Osmosis, '52-203
RI/FS
Bridgeport Oil and Rental Services Site,
'55-299
Risk
Acceptability, '55-405
Analysis, '57-230; '55-37
Computer, '54-300
Environmental, '52-380
Assessment, '57-238; '52-23, 386, 390,
406, 408; '55-342; '54-283, 321; '55-383,
412, 449
Air Quality, '52-63
Comparative, '55-401
Health, '54-230
Manual, '55-419
Modeling, '52-396
Prioritizing, '55-433
Quantitative, '54-290
Remedial Action Alternatives, '55-319
Underground Tanks, '54-16
Cleanup Level, '55-398
Design, '54-313
Evaluation, '50-25
Minimization, '57-84
Rocky Mountain Arsenal, '57-374; '52-259;
'55-36
Safety (See also Health and Safety)
'52-299, 306; '55-406
Cost Impact, '52-311
Information, '54-59
Plans, '54-269
Procedures, '57-269
Remedial Construction, '55-280
Sampling and Analysis, '57-263
Tank Investigation and Removal, '55-198
Training, '52-319
Sample Thief, '57-154
Sampling, '50-91
Analysis
Safety, '57-263
Biological, '52-52
Drums, '57-154
Impoundments, '55-80
Screening, '57-103, 107, 114
Strategy, '55-74
Subsampling, '54-90
Techniques, '57-143, 149
Screening
Analytical, '55-97
Mass Selective Detector, '55-102
Metals, '55-93
Spectrometry, '55-291
Security, '55-310
Seismic
Boundary Waves, '55-362
Refraction, '50-239
Sensing
Downhole, '55-108
Serum Reference Methods, '54-243
Settlement, '55-275
Agreements, '52-470
Hyde Park, JS5-307
Shenango, '50-233
Shock Sensitive/Explosive Chemical
Detonation, '54-200
Shope's Landfill, Cleanup, '55-296
Silicates, '52-237
Grouts, '55-175
Silresim Site, '52-280
Site
Assessment, '50-59, 91; '55-221; '54-221;
SUBJECT INDEX 493
-------
'55-209
Discovery, '83-31
Evaluation, '80-25, 30
Hazard Rating, '50-30
Inspection Sampling Strategy, '55-74
Investigation, '55-48
Location, '50-116; '57-52
Location Methodology, '50-275
Problems
Whales, '54-594
Reuse, '54-363, 560
Siting, '50-1
Hazardous Waste Management Facility,
'54-517
Public Information Needs, '54-368
Slurry
Trench, '52-191
Wall, '55-357, 374
Small Quantity Generator, '55-14
Smelter Lead, '54-239; '55-442
Soil
Advanced Technologies, '54-412
Contamination, '52-399, 442; '55-43; '54-
569, 576
International Study, '52-431
Pesticides. '55-243
Extraction, '52-442
Gas Sampling, '54-20
Geotechnical Property Testing, '55-249
Thermal Treatment, '54-404
Vapor Measurement, '55-128
Washing, '55^*52
Soil-Bentonite Slurry Walls, '55-357, 369
Solid Waste Management
China, '54-604
Solidification, '57-206
Silicates, '52-237
TNT Sludge, '53-270
Solvent Mining, '53-231
Spatial Contouring, '55-442
Spills
Hazardous Materials Storage, '52-357
Stabilization, '50-192
Viscoelastic Polymer Waste, '55-152
Stabilization/Solidification, '50-180; '55-214,
231
Organic Sludge, '54-189
State
Criticism, '54-532
Enforcement, '54-544
Participation, '52-418; '54-53
Plans
New Jersey, '53-413
Pennsylvania, '57-42
Superfund Program, '52-428; '55-67
Statistical Methods, '54-243
Groundwater Monitoring, '54-346
Steam Stripping, '52-289
Stringfellow, Site, '50-15, 21
Subsampling, '54-90
Subsurface Geophysical Investigation, '54-481
Superfund
California, '57-37
Cleanup Failure Liability, '53-442
Drinking Water, '53-8
Federal/State Cooperation, '5/-21; '53-428
Implementation, '53-1
Management, '53-5
Private Sector Concerns, '5/-10
Programs
New Jersey, '52-413
Texas, '53-423
State Perspective, '54-532
USEPA Research, '57-7
Surface
Sealing, '57-201
Water Management, '50-152
Swansea Valley, '54-553
Swedish Dump Site Cleanup, '53-342
Sweeney, '52-461
Sydney Mine Site, '55-285
Sylvester. Site, '57-359
Synthetic Membrane, Impoundment Retrofit,
'52-244
Tailings, '55-107
Tank Investigation and Removal, '55-198
TAT
Health and Safety, '50-85
Technology Evaluation, '52-233
Texas
Ambient Air Sampling, '55-125
Superfund Program, '53-423
Thamesmead, '54-560
Thermal Treatment
Soils, '54-404
Thermodynamics
Halogen Combustion, '55-400
TNT, '52-209; '55-314
Top-Sealing, '50-135
Town Gas, '54-11
Toxic Substances and Disease Registry Agency,
'55-403
Trace Atmospheric Gas Analyzer, '53-98, 100
Training
First Responders, '55-71
Resources, '53-304
Treatment
In Situ, '52-451; '53-217. 221, 226, 231
On-Site, '52-442
System Design, '57-294
Underground Tank
Spill Risk Assessment, '54-16
United Kingdom, '50-8, 226
Unknown Gases, '54-416
U.S. Army Corps of Engineers, '52-414; '53-
17
U.S. Army Installation Restoration
Program, '54-511
U.S.C.G., '50-6
U.S. EPA
Mobile Incinerator, '57-285
Research, '57-7
U.S. Navy, '55-48
UV/Ozone Study, '55-456
Vados Zone Monitoring, '52-100
Vapor
Emission, '52-326
Soils, '55-128, 157
Viscoelastic Polymer Waste, '55-152
Vitrification
In Situ, '54-191
Volatile
Nitrogen Compounds Monitoring, '53-100
Organic?
Emissions, '57-129; '54-68, 77
Monitoring, '57-122; '54-72
Wales, '54-594
Walls
Gelatinous, '52-198
Slurry, '52-191
Waste Storage
Above Ground, '52-228
Wastewater Treatment, '50-160; '54-598
Water Treatment
Cost, '53-370
Waterway Decontamination, '53-21
West Germany, '53-68
Wetland Contamination, '55-261
Wilsonville Exhumation, '52-156
Woburn, MA, '57-63, 177
Wood Treating Facility, '57-212
X-Ray
Analyzer, '55-107
Fluorescence, '55-93
494 SUBJECT INDEX
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