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 th |