WASTE SITES
          DECEMBER 1-3, 1986 • WASHINGTON, DC

            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

    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.

     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.


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
  Jim Makris
Improvements in Superfund Site Management 	
  Christopher Sebastian, John Mateo, Randall
  Kaltreider & Martha Monserrate


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.

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
                                                             Improving and Implementing Superfund
                                                             Contracting Strategies	46
                                                               Stanley P. Kovell

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



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.

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


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


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
 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
   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


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








Leachale Characterization and Synthetic
Leachate Formulation for Liner Testing	
  Jennifer A. Bramlett, Edward W. Repa, Ph.D.
  & Charles I. Mashni

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.


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

 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
   Michael F.R. Curry







              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
                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.

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
  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


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
  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

 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










The Soil Chemistry of Hazardous Materials:
Basic Concepts and Principles	
  James Dragun, Ph.D.
Exhibitors	475

Author Index 	485

Subject Index	490

                      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
  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.

  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-
  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.

  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

 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-
  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.

   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


 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
   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

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-

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
bleb uplo*i*M

              Safety Improvement Using  Simulation  and Advanced
                        Control  in  Hazardous Waste Incineration
                                                      S.K. Shoor
                                                     R.J. Clinton
                                      Combustion Engineering Simeon, Inc.
                                              Bloomfield, New Jersey
   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.

  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.

  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.

                  v«it      v«n
                          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.

  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
  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
  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
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
• 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-
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-
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

 and optimization are summarized below.
   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.

   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.

  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-
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

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.

  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
                                                                                    IMPLEMENTATION OF SUPERFUND

                   Deleting  Sites  from  the National  Priorities List
     Amelia Z. Heffernan
     Kathleen A. Hutson
Booz,  Allen & Hamilton Inc.
     Bethesda, Maryland
       Steven C. Golian
Environmental Protection Agency
      Washington, D.C.
   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
   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.

  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."

  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-

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
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).

  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

  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.

  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
  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.

   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-
  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.

  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.

                                  Implementation of Superfund:
                                     Community  Right-to-Know

                                                      Jim Makris
                                      U.S. Environmental Protection Agency
                                  Office of Solid Waste and Emergency Response
                                                  Washington, B.C.
  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.

  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.

   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.

   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
   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-
   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-

   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.
  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
  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.

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

                    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
   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.

  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.
  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

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-
  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.

  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

            This is i selective report.  All item shown
              i Notes II) begins "HI/PS*
66 87
Jul Aug Sep Oct Nov Dec Jin Feb Mar Apr Hay
Status 11 11 111 1111

Rl Report Review C
Analysis 1 FS Report C

FS Review

Final FS Submitted p
FS to Public C
Public Coavent Period C

POP Negotiations C
Design Assist. Funds to Corps p 	
A/E Selection for RD (Corps) C 	
Prepare IAG for RD 	

RA/AA Briefirq Period C . ....

D Done M Task - Slack tiie (• — ), or
C Critical in Started task Resource delay 1 — »)
R Resource conflict M Hi Intone ) Conflict
p Partial dependency
Scale: Each character equals 1 week
Jun Jul Aug Sep Oct Nov Dec Jan Feb Har Apr Hay Jun Jul
11 111 111 111 111


. (t 	



^ —
	 H .
	 X . .

	 H . . .

	 . N — . ...
	 . .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.
                                                               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

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 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

  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

                                  Maximizing Cleanup  Options
                     And Minimizing Liabilities  Under CERCLA

                                              Theodore Hadzi-Antich
                             New York State Environmental Facilities Corporation
                                                 Albany, New York
   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
  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."

  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-

  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

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.

  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
  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.

  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
  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
• 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
  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

 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.

   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
   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-
   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.

  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
  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.

  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.

 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
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

                       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
   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.

   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

  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.
  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-

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).
  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-
  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.

  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
  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
• 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
  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

  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
  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-
• 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

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

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
• 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
• 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-
  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.

  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-
• 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

 •  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.

  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.

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.

                     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.
  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.

  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.

  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-
  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-
  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

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.

   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  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

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

  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

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.

  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.

                            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
  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.

  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-
  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.

  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

  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.

  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
  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-
  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
  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-
  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

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.

  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
  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.

  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

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

  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.

                                  Remedial  Planning  Contracts

                                                 Nancy M. Willis
                                    U.S. Environmental Protection Agency
                                       Remedial Action  Contracts Branch
                                                Washington, D.C.
  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.

  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

  U.S. EPA has three large remedial planning contracts:

  Period of
  Area of
                      - Camp, Dresser and McKee

                      -June 1984 - June 1988
REM 111
Period of
Area of
Period of
Area of
                        - EBASCO

                         November 1985 - October 1990

                        Region I - Revion IV

                        - CH2M Hill

                        -November 1985 - October 1990

                        - Region V  Region X
  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-
                                                           • Program management hours
                                                           • Level of effort hours
                                                           • Subcontract pool
  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-

• 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.
                                                                               U.S. EPA SUPPORT CONTRACTS    35

                        The  Field  Investigation Team  Contracts-
                                           Scope and Functions

                                                    Scott Fredericks
                                      U.S. Environmental Protection Agency
                                                  Washington, D.C.
  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)
• 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


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 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
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-

ing operations: QA, subcontracts, technical operations, manage-
ment information systems and reports and the overall Program

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.

  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:
Zone I—56M
Zone II—59M
Level of Effort
  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

                       Technical Enforcement Support  Contracts

                                                    Nancy Deck
                                    U.S. Environmental Protection Agency
                                    Office of Waste Programs  Enforcement
                                                Washington, D.C.
   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.

   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 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 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
                                                         Techlaw, Inc.
                                                         Labat Anderson, Inc.
                                                         PriedeSedgwick, Inc.
                                                         Geoscience Consultants
                                                         SRA Technologies
                                                         Life Systems
                                                         Hydraulic & Waste Resources Engineers
                                                         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

• Putnam, Hayes, & Bartlett
• Geo/Resource Consultants
• Battelle Pacific Northwest Laboratories
• Development Planning and Research Associates

  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-
• 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.

  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.
  To be discussed at the Conference.

  To be discussed at the Conference.
                                                                                  U.S. EPA SUPPORT CONTRACTS    39

                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
    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
       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
            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
         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
            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

  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.

  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

  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
  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.

  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
  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
  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.

  Successfully implementing  emergency responses to releases of
                                                                                     U.S. EPA SUPPORT CONTRACTS    41

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-
   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

conference, provides greater detail on ERAs.

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
  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

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
  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.

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

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

                        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.

                    Addressing  the Consultant's  Liability Concerns

                                               Laurence T. Schaper, P.E.
                                               Dennis R. Schapker, P.E.
                                         Black & Veatch Engineers-Architects
                                                  Kansas City, Missouri
  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
  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.

  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

   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

Other Design Firms
Other 3rd Parties
  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
  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

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
• 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-
  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.

  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 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

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
• 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

Modifies or
Joint &
Several Liability

Cap on

New Hampshire
New York
South Dakota
West Virginia
* cn
X 250, 000 l '
450,000,. X
Varies u;
X 225, OOO1- ;
1 b)
875, OOO1 '
* /3\
X 1, 000, 000 ^
X Tied to life
(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 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

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
  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-
• 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.

  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-
  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-

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.

  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
  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.
  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.

  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

 I.  Compen»tor> Damage*

    A. Special Damage*
        I. Medical Care Expenses
        2. Loss of Income
        3. Medical Monitoring
        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

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
Health Environment

Properly & Defense &
Income Losses Cleanup Costs
Federal Local

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.

  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.
  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
  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.).


  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
of Lou
RAC Graf
Layeri of Litbimy in Caiei of RAC
Potential RAC Unlimited
Liability Layer
EPA Indemnification Layer
(Subject to Limit! and Deductible
Reipooiible Parly Liability Layer
(e.g.. Indemnity Agreement!)
Available Commercial Property It
Catualty Iniurance Layer
RAC Deductible Layer
Riik Handling
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.

  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
• 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
• 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.

  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
    Probability Tree
  Potential Damages
  Assessment of RAC
   Legal Analysis
(Including Potential
Defense Cost Analysis)
  Deductible Analysis
  Risk Comparison
                      Development of RAC
                      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
  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-

  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
  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.

  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-

  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

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.

   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
   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
•  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
•  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

  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
Qty. of
                       Type of Waste
 B       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
Soil Permeability
Extremely low stiff clay
Moderate-silty clay
High-sandy clay
Depth to
First Aquifer
300 +
300 +
  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
 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



                                                                                            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

 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
   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
                            Table 4
             Site 1 — Information from Site Assessment
                            Table 5
            Site 2 — Information from Site Assessment
                        Qty. of
                      Waste (toot)
   Qty. of
  Soil (ydl)
                                                     Qly. of
   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




Qty. of
Wade (low)

Qty. of
SoH (jrdJ)
Qly. of
Quantity of Contaminated Free Water in Impoundment — 100 K gal
                                    FREE WATEfl
       aiTI 1
                                    FREE WATER
       atri a
                                   FREE WATER
                                                                        BOUNDARY OF CONTAMINATED OROUND WATER





Qly. of
Wute (tons)

Qly. of
Soil (yd3)

Qty. of
 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
  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

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


Site 1
K$ °7o

427 33.33
427 33.33
427 33.33
1,281 100.00



Site 2


Site 3



o Treat Contaminated Water 100
o Excavate Waitel 2,310
0 Incinerate Watte 2,310
o Baddlll and Vegetate 2,3SO
o Excavate Contaminated Soil 13,000
and beddlll
0 Vault Contaminated Soil 13,000
Units SAInit
Kgal 30
yd' 10
yd» 13
yd' 20

yd' to
Portion of Coat to Indicated
ComDOny. KS



Total. KS

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




Treat Contaminated
Surface Water
Excavate Watte!
Incinerate Wai te
Bactilll and Vegetate



















. "









Total. KS




                % Share
                            Table 8
               Site 2 — Proration of Closure Costs
Quantity Unlta
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
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
W Share




Portion ol Coat to Indicated
Comronr. KS
A t, t
__- _




• 7.1
Total. KS
                             GROUND WATER REMEDIATION




• 17
  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.

  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
  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
  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.

  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
• Completion of preliminary site assessment
• Completion of Remedial Investigation and Feasibility Study
• 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
  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

  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.

                 Considerations  of Discounting  Techniques Applied
                                  To Superfund  Site  Remediation
                                               Thomas J.  Buechler, P.E.
                                                  Keith A. Boyd, P.E.
                                                     Black & Veatch
                                                 Kansas  City, Missouri
   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.

   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.

  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
  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-
   Net present worth can be expressed as the equation (2):
   NPW =
                              - 1
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.

   U.S. EPA guidance documents3-4  specify the use of present
worth analysis to  compare  remedial  alternatives. The develop-
                 •  ocrim ALTEHUTIVU
                 •  Dtmimn nun ruioo
                 •  nonot UTIMTU or CAU
                    nan rat ALTBUUTIW
                      niton mm
                     INPUT TO DtCllIOK
                      MAKING HOCUS
                       SJLJCTIO* or
                    REMEDIAL ALTDUUTIVI
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
  The discount rate can be calculated as follows:5

(1+K)  = (1+Rf) (1+Ei)  (1+Rp)                         (3)


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.
  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
  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

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:
 Annual Costs:
   Extraction   $111,600
   Injection      127,200
   Treatment    103,300
   Monitoring     49,000
 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
  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
  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
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.

                 The Application  of Quantitative  Risk  Assessment
              To  Assist in Evaluating Remedial Action Alternatives
                                           Lawrence J. Partridge, Sc.D.
                                            Camp  Dresser & McKee Inc.
                                               Boston, Massachusetts
  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.

  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

  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
                      Spteify Individual Watia
                      Malanala for Inclunon in
                      Pathways and Fata Analysis
                        |0«t«rmint F»U of
                        Individual w»tta

Calculata Exposura Lavals
(or Each Population
CalcuUltd Butllna Bilk
for No-Action Allarnallv*


Populatlonl at


                          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-
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-
  ol Response
  si Dose D Over
                           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
  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) 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
(t-s1)k - (t-s2)k
   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  =


   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
                             4 nag* moat)
                          only lint lligt ao» -tltlM
               10       20       30      40
                            Y««r» of «ipo«ur»
                            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.

  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.

  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
  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.

  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.

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.

                             Risk and  Exposure Assessment  of  an
                                Abandoned  Hazardous  Waste Site

                                                   James D. Werner
                                            ICF Technology Incorporated
                                                  Washington, D.C.
  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.

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  (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
  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

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 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
  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
                           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
3 8





or surface water concentrations that were higher than observed
during the actual air sampling period.

  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
  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.'

  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.
  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.

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
  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

  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

Poiaonino by vitaaina
ftotul ia«
Saallpox vaccination
whooping cough
Vanoaoua bit* or Btlng
Hon-vano«oue anlaal
Cxcaat cold
Pragnancy, birth, abor.
Infactioua hapatitla
MV/train colllaion
Firaara accldant
Polaon by aol id/liquid
rlra and flaua
Accidental (all*
Braaat cancar
Motor vahicla accldant
Lung cane r
Sto»ach c near
All accltf nt«
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«
7,}>0 •
55.J50 4
111,750 1
111,000 4
7)1,000 1
740,450 »
, 161










  Tot«l number of reports (causes 29,  Ji,  37, 41)

Source: Combi, B. and Slovic, P.. Journalism Quart , 56. 1979, 837.
                                                1113  910

                      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.
  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
  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.

  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-

  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
                                       Nol Dread
                                       Nol Global Catastrophic
                                       Coiuequencci Nol Fatal
                                       Low Riik to Future
                                       Easily Reduced
                                       Riik Decreailni
                                       Doetn't Affect Me
Factor 2

Not Dewrvable
Unknown 10 Those
  Ei posed
Mf«i Delayed
Nc» Riik
Risks Unknown lo
Known lo Thote Elpowd
Effect Immediate
Old Riik
Rliki Known lo Science
' Dread
 Global Caiaitropic
 Consequences Fatal
 Not Equitable
 Calaiirophic   Factor I
 Hi«h Riik to Future
 Nol Easily Reduced
 Riik Incraulni
                                                                Figure 2
      Factor analysis of risk relationship among hazards. (Adapted from Slovic, P., "Informing and Educating the Public about Risk." In press.)


  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'
  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
  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.

  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.

1. Slovic, P., "Informing and Educating the Public About  Risk." In
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
  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
  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.

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-
  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

mid-1982, MDH and CDC reinitiated public health activities on
the basis of new information and additional environmental data.

  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-

  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
  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

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-
  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
  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

  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
  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

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
  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.

  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
   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-
   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.

  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

• Roads, arenas,  parking lots sprayed with waste oils throughout
• Deaths of rodents, birds, horses in  three Missouri horseback  riding
• Child presents with hemorrhagic cystitis
• Epidemiologic investigation implicated oil spraying but specific agent
  could not be identified
• 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
• 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-
• Times Beach is evacuated after extensive contamination is found in
• Pilot study
• Central Listing set up
• Chloracne screening clinic
• Follow-up epidemiologic study recommended
  Quail Run Study begun

  Quail Run Study finished
  Missouri Adipose Study begun
  Reproductive Outcome Study begun
  Quail Run Study results published
  Follow-up of Quail Run Study participants  with immunologic ab-
  normalities carried out
  Initial results of Adipose Study released
  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.

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.

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

                     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.
  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
  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

  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.

  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.


  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

  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.

    H YES

    H NO
                            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











                                                                         RESPONSIBLE PARTIES

                                                                         STUDY SELECTED
                                                                         GEOGRAPHICAL AREA
                                                                         STODY SELECTED
                                                                                               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.

  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
         POM EFA
                            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
                                                              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
1 (WHIM. O*m Imimllem ~
I Prop«ny Tantti n*i}**u*
J. fMmtoOMrEPABmdi"
4. PA/SI ny pmrtrt -
I Sph
I RttenfeOtwJfemy"
7. CHnnConpUn
» Infamy**)! Slu*
10. OMgnpNcArai
11. RMpoMlHl PMy tepofl "
12. HMoitcil SnOHFIt R«
                                                              > n»«t« nwtbori *r« t
                                                                                        irUtatl i

                                                                                        itlv* a

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
  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.
   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
  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
  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.
                                                            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

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
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.
  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
  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.
  The verification process generally is performed to provide addi-
tional  assurance that the contaminant transport model is an ade-

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.
   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.

   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
  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.

  Contaminant transport models are important tools in  haz-
ardous waste site investigations. They can be used to simulate

                   SITE DISCOVERY  & ASSESSMENT    91

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.

1. Mercer, J.W. and Faust, C.R., "Groundwater Modeling," National
  Water Well Association. 1981.

                           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

  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.

  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.

  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.

  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
• 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

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
  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.

                   3 BLOWER
                              TO DECANTER
                            Figure 1
       0-w¥->*.  lll^
       IUN  i    i  •'•   r—n
       H          I     I
           1    '    A
                                                 CARBURETED GAS
                                                   TO BOOSTER
                               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
                                                                                         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:

                                                             Coal/Coke Gasification
                                                             Gas Cooling
                                                             Gas Cleaning
                       By-prod acts
                       Clean Gas
                       Ammonium Sulfale

•\-.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.


  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

  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

Free sulfur
Ferric monohydrate
Ferrous  monohydrate
Basic ferric sulfate
Ferric ammonium ferrocyanide
Ferrocoferric ammonium ferrocyanide
Ferric pyridic ferrocyanide
Organic matter peat  fiber
Pyridine sulfate
Ammonium  sulfate
Calcium sulfate
Ferrous  sulfate
Ammonium  thiocyanate
Sulfur otherwise combined
Organic matter soluble in alkalies
Combined water and loss (by difference)
Concentration (%)



                            Table 2
                  Characteristic Compounds Found In
                    Manufactured Gas Plant Tars1

  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
  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

                          Interviews with
                          Former Employees

                          Water Resource
                          (or equivalent)
                          Utility Records
                          State/Local Agencies
                          US FEMA

                          US Soil Conservation

                                                                     Site Visit
Reference: ERT/Koppers,1

                       • 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

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
Phased Site Investigations
  Site investigations are conducted to achieve the  following

• 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).


  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.

 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.

                     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
  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.

  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.

  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
  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

  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.

  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-
  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
                                                    Summery of Herbicides U«ed
of Application
August 23,24,
25, 1965
May 7,8,
May 31,
June 1,2,3,
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
propylene glycol
butyl ether ester
propylene glycol
butyl ether ester
Monsanto 524-115 1 lb
Thompson- 148-431 1 lb_
Monsanto 524-115 1 lb~
Thompson- 148-431 1 lb
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
butyl ester
2-ethylhexyl ester
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.

       HERBICIDE    USE    AREA    1965-1969
                                                       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
 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.


 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

  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.
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.

  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.

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

                                                     Table 2
                                             Summary of Wildlife Collected
Common Name
Scientific Name
Canis latrans
Black Rattlesnake
Crotalus spp.
Odocoileus virginianus

Dicotyles tajacu

Glossy Snake
Arizona elegans
Gambel's Quail
Lophortyx qambelli
Garter Snake
Thamnophis radix
Euro cognatus
Leopard Frogs
Rana pipiens
8 months
1 year
57 Ibs
23 Ibs
SO Ibs
56 Ibs
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
by Hand
by Hand
Tissue Sampled
, Kidney, Fa
, Kidney, Fa
, Kidney, Fa
, Kidney, Fa
, Kidney, Fa

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
                          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.

                                                                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.
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.

               FOLLOW-UP  STUDY
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.

  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.

  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.

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.

                           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
  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

  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.

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


                         Rapid Field
                       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

1 , 1-Dichloroe thy lane
1,1,2 -Trlchloroethylene
1,1..; , 2-Tetrachloroatnylene
                                                                                Total PHAa-Soll/eolvent

                                                                                Total PRM- Hater
                                                   1-10 ffm (o;/9|

                                                                        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
10 rmjc
                                                                       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.

  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

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
tig/9 or jig/11
Water Matrix
Recovery (t)

BSD (%)2

Recovery (%)

USD <«)2

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
                                  . Pit* Concentration. »q/« or tia/l
1C. 4
21. C
33 v
          (2nd lit*)

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

 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


 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
  1. Not Present.
  2. Unknown VOC is possibly irans-1,2 DCE

                             Table 7
          Estimated Cost Breakdown for Field Implementation'
  PNA Screening
 Analytical facilities
  (UV fluorescence  spectre-photometer,
 recorder, analytical balance,
 refrigerator, lab trailer etc.)

 Disposable equipment

 Manpower (2 operators)


 Estimated average cost  per sample

 Volatile Organic* Screening

 Analytical facilities
 (photovac,  recorder,  lab  trailer,

 Disposable  equipment



 Estimated average  cost  per  sample
                                 $800   $900/week



                                 20-30 samples/day





                                 20 samples/day

 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.

  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.

   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

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
  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.

  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.

  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
  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.

  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-

  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*-

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
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.

  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
• "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

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.

  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
•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,
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.)        -

             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
  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.

  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

  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.

   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.

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.

  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.

                  XRF Calibration Piranclcn

Sit* 1

Sltt C2


 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

   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

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
                                            CV (X)
Site A
Site B

Site C2

1  Method detection limit
2 Model #5 (20 calibration samples)

  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)                	
  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
  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)

      13 -

      12 -

      II -

      10 -

      t -

      a -

      7 -

      a -

      9 -

      4 -

      3 -

      2 -

      1 J

                           Figure 4
             XRF vs. CLP for As in Site B Soil Samples
                              IRON (X)
                 i        4        a
                           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
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1110 - 40)0
n M • 1140
U It . 1000
1000 . 41)0
111. « n « - lo.ooo
tu> c1 n it - 1100
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-It 11
-t u
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1 It
0 11
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iti m
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UI 111
0> III
» M
in- m
in no
»i m
ui« iti
lit 110

-1 tl
 I Model 5 (20 Calibration Samples)
 • - itfnifkani difference

transformed data. The results given in Table 3 were evaluated as
• 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.

  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 («)

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

 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.

  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
 • 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.

  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 A
Site B

Site C1

S2 Saaple
of Total Variance
S2 Calib. S2
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.

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,
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
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.
  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
  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.

  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
  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  (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
  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.

                                                             Table 1
                                  Comparison of Gas Chromatographs Used by Field Investigation Teams
                            OVEN TW RANGE
                                                              DETECTION LIMITS*
                                                                                              SPECIAL FEATURES
| AID-511
| Shtadzu Hlnl-2 & M1n1-3
| Photovec todel 10A10
| rNu motel QC-301
| OVA model 128
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
   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
 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 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-

  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
  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

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.
         Cools of M«Jor Eqalpncnt for Mobile Laboratories

                                               Cost (I)
K/HS, *m itllm piirfe ** tr*
(volatile «rf«1ct). >f*
BC/NS, aiti *jite» Mto-iH»ler

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

ICtf (Mtllt)

MS-eraaklle firaaco

TOC anetyter (uretnlnf for total
          erfMlc CMceotretio*)

TO! analyier (tcreentaf for aeleanate*
BO. 000



















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.
« 70.000
U 50,000
   •Difference! In price reflect varying detract of capability to meet data quality objective).

  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/
• 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
   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
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
  Total Yearly Operating Costs
                                         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
  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
                                   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
        Data Quality

        Mobilization time

        Capital costs

        Yearly operating costs


        Analysis days/year

        Analysis rate
litigation quality

pre-planning required


$1.130.960 (2 shifts)

8 days

180  days
confirmed screening  (organic*)

rapid  response



S days

ZOO days
6 samples/day (2 shifts)    12 samples/day
unconfirmed screening

rapid  response



5 days

200 days

12 samples/day (avg.)
       Max. samples/year (1)        1032

       Cost/sample                 $1,096


       Max. poss.  sites/year (2)    20

       Cost/sample                $9,425


        (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«.


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.

  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.

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
  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
  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.

  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.

  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
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.

• Pits 2 and 3
  Pits  2  and 3  contain  primarily  municipal and  commercial
 •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
 • 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
• 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.

  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

  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
                                       THREADED 41.0. STEEL
                                       SURFACE CASING

                            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
                                                                                                          WIRELINE CABLE
                                                                                                          OVERSHOT LATCHING
                                                                                                          NW CASING
                                      RETRACTABLE 2 15/16'
                                      TRI-CONE ROLLER BIT
                                      W/ LOCKING INNER SUB
                                      DIAMOND TIPPED CASING
                                      ADVANCER  (REAMING SHOT)

                           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

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
   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
- -
- -












0 IN.






N 44fl.22Q.941 E 2.546.790.301
GWL: DEPTH 1A15' DATE/TIME 3-14--M/075.
1703' OATE/nUE 3-15-86/073


3-6-BB/OB40 MRS.
3-4-86 SET 1-4* STEEL
AUGER TO 4.5'.
S-1 LAB SAMPLE (3.0'- 5.0')
S-2 LAB SAMPLE (B.5'-11.5')
HARD DRILLING 14.5'-1B.fl'
S-4 LAB SAMPLE (19.5'- 21.5')
S-5 LAB SAMPLE (24.5'-26.51)

— J5-
— 55—












6 IN.







N 446.220.941 E 2.546.790.301
SURFACE EL: 999.7'
DATE BEGAN: 3-fl-§6
CWL: DEPTH JJJi DATE /TIME 3-14-66/0755
17.0? DATE/TIME 3-15-66/0731

. J

  Figure 3 (Continued)
Log of Boring No. P5—4


5. *"




20'-30' 2' STAINLESS STEEL SCREEN (0.01')
34'- 58' GRAVEL
B5-2DB GWL: DEPTH 19.15' DATE/TIME 3-14-86/075
3-6-86 ,7.02' DATE/HUE 3-15-B6/073

0 I

VERY HARD DRILLING 6 3.0'- 6 4. 5'

                             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





— o

CAmMQE/nu M47EHr/u.


/ .. — 1' PVC SCREW CAP (UNVt

— •

:*••' ^ — CONCRETE (4.51)
ji^ 	 n" DIA. BORING
^ — 3.«2S* DU. BORMC

^^^^ RISER P»«C

.s^ SCREEN (0.01T
^x^ Oa
  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
• 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
  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
  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.

  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.

  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.

  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-

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.

  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-
  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-
                      4	10m	h
                     O      -     Q
T3 =00
°2 = °A
Vadose Zone
                        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.

  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« |
                                  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.

  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-
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.
 •i   100H
                               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
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
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

              =   v
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.  =
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
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.

  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
                                     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
                        40                80
                            Station Numbar
                                                    220. .210
                           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.

  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.
                                                 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.
1 ,-
o .

I— 1 0-60
ES3 60- 100
S3 100- 200
m 200- 400
ES3 400- 600
HB *00- 800
         mm 8oo-i3oo
                              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-
                                               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

  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.


  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.


  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

  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
 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
• 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,

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

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.

  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

  The objective of the first set of experiments was to determine
whether TCE concentration in soil gas is a function of time and
  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
  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.

  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

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.

   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
   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.

   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.

  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

(.0 -

J.O -

1.0 -


a a a
a a a
DO ° o
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

LO| lBlll«
Soil Omt TCE
Pe»k H>l|kl
Soil TCE
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.

  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
• 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
• 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.


  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.

                           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
  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.

  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

  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
• 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
• 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
  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.
    Project  Requires  Sample Collection
         Data objectives determined
         for  Study (Project Officer)
            Sample Plan  Written
                (  Team A )
           Sample Plan  Reviewed
                ( Team  B )




Laboratory Analyses &
Field Sampling Scheduled
Field Sampling
Samples to Laboratory
for Analyses

Data to Reviewers for
Data Validation

Validated Data to
Project Officer
                                             Do»I field
                                               AT. nlMllwi <>»U
                                              .ulfict.nl to Mhl«»
                                               siudj obj«u«> *
                          Figure 1
     Sampling Event Diagram: Planning, Review, Execution and
                       Decision Points

  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.


  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
           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:

                            Date Audited:

                            Date Sampled!
  1}   Was the well locked?

  2)   Is the well vented?

      Is the well clearly labeled?
  4)   Does the integrity of the surface seal appear adequate?


                                                          (Y/N) .

      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? 	
  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


  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?


 11)   Was a Discharge Rate measured during the purging?

 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?
      Was the sounding equipment decontaminated after use?              (Y/N)

  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.


  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
                                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?	
  «) 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?
   ) Are equipaent rtneete/eethode blenke oollecteo7
 IT) Are field blinke collected?

    Ha. traquenUy? 	
 16) teut U the eource at «eter lor the tjl«n» >Mplee?_
                               neld Hendling
 19) Panaetec     I/Type of Container   and Preeeryetton




    Anlone fc Cet






    Suit idee

 20) Ho> Ireguently an Uie lenplei ehlppM? 	

 211 Milch laboratorlea are being uMd tor thla wnpllng event?
ions which might be made during a sampling event. Sample team
members as well as auditors must be experienced enough to judge

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.

  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

  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

  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.

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

                     The  Importance of  Field  Data  Acquisition  in
            Hydrogeologic  Investigations at Hazardous Waste  Sites
                                                 Richard J. DeLuca
                                                  OCA Corporation
                                               Bedford, Massachusetts
  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-
  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.

  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-

  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
  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
   Both of these  technologies require an extensive data base to

evaluate these options. This data base is generated during the re-
medial  investigation and is extremely important for a success-
ful remediation.

  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.
  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

  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.

  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
  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

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.

  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
 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,
 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
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

                          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
  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.

  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

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.

  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.

  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-
  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
  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.
  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.

   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
              Summary of Air Sampling Methodologies

        •  Scopt
        •  Objective!


        •  Topographic Inscription
        •  Land UM Oticrlptlon
          Source Description
        •  Climatologies! 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)


        •  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

              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
  Ctlwlaetrlc    ImteManwH  mtUrlc  HrKt   0.1-1.0  tartan      In,
  Diucur li*M                   Re-lia        •'»"'" a«*   «N
                                                      », aw
  Btucur (MO)
  BtucUr (fie)  lnUereM
                         I rt«t  (tract    0.*
                      »Mi lui  liract    O.I   (tot OrfMtcs
  rieu ec     IMUMMMH  Niuaric,  lirect  o.ool-o.l  Nnt OrfMicf   n*& an
  linmn     IM»r«U<   Start Time a^Mlne                   mn Inilii.
                      •elay                           •«!«•
  Mi^eg*     lnUfntM   mturic   I*    «arim>ia  T«ui f     sm> M
  •Mil/                         *"•'»"•        «^<"     "alieiseii
                       UlUrlc   U»    Vvl*l< TMal tr
            InUaratad           AMlinl*       i««cin
              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
• 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

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)
   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
  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.

  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.

  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
  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-
  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-
  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
  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

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-
  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-
  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-
  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.
  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
  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.
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,
4.  U.S.  EPA, "Quality Assurance  for Air Pollution Measurements
   Systems," Vol. 1, Principles, EPA-600/9-76-005, Jan. 1976.
                                                                                          SAMPLING & MONITORING     157

               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
  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.


  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.
  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
  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.

                         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.

  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
                                                                 DEPTH  (FT.)

                                                                                                      CLAY  AND
                                                                                                   =j] SANDY  CLAY
                                    SAND  AND
                                    SILTY  SAND
                                                                                                     CLAY  AND
                                                                                                     SILTY  CLAY
                                    (NORCO  AQUIFER)
                                    {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
Tillltl fTTtll





   •Qrltwrlcn in thl» CM I* 10~* «n:im llfltlH cwnr riik in UM of •
   drinkirg Mtor KffQy with th« lisud coitjaimit uimiLnticn.

  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.


  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
  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
  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

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.

  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

  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.


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
W-12           PVC
W-14           PVC
H-16           PVC






  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
                                                                                             Low level

                                                                                             Inw level

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.

  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.

  As a result of this careful study of the Cleve Reber Site to detect
                            Table 4
        Water Quality Results After Multiple Well Samplings
            Program Installed
              	Cone,  frotl





Low Level

Low Level
4/19 (1 IM)
4/19 (4 IM)






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
  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%.

  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 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
  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-
   Po(N, T, n)  = a
   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.

                                                           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.

  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
• 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-

  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

Pb Conc.(ppm)
CD 0-800
•I 801- 1000
• > 1000
^Drilling Raluaal
CD] Nol Analyiad
DaptM II.)
y ;
6 ample No.

                            'Statistically determined
                                sampling  location
                                        N = 49
                            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-
• 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


   Pb Conc.(ppf)    0«plM ll )

  CD   0-500
  •1501- 1000

  •I  >1000
  ^Drilling Rduial

  [III Not Analyzed
00    1
 t     *
Sampla No.

— Railroad
       GRID: 2«' «  IB'

^Statistically determined
    sampling location
           N = 90
                            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

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.

                                      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.
  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.

  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
                                               RISK MANAGEMENT
                         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

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.

  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.

  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
  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

HO 0»t»
evidence or
•0 CFftCT
A « « A
1) 11 11 II
12 C 0 D
W C 0 0
tt C 0 0

IVIBlfcci a
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

    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
  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
• 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.
   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
   •  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

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
  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.


  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-
• Pathways and fate  analysis—a  description of how a contami-
  nant may transport from the source to the potentially exposed
• 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
• 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
  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
                               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
• 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.

  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

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.
   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.
   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 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
  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

  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.

  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.


  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.

  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.

 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
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
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.

                      A  Comparative Evaluation  of  Methods for
                   Determining  Alternative  Concentration Limits
                                                 Gaynor W. Dawson
                                                  C.  Joseph English
                                                    ICF  Northwest
                                               Richland, Washington
  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.

  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 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 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-
  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 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

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.
                         '• Contaminant
                       Fully Developed f

                          !• 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.
                                                                     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.
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
  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.

  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.

  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

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
                                           OWUEE/OPERATOR .
                                        FACTOR               KAIIKUH
                                        RATIK  HULTI- FACTOR  POSSIBLE


_ 12
  Phyi. char. Subacore:  (100 x factor aeor* eubtotal/aaxli

                                              I aeore aubtotal).
                                        FACTOR               HAXIHUH
                                        RATIHC  RULTI- FACTOR  POSSIBLE


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.

  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.

    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.


                                                                            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


        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


     ••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«
Uooto ChorcctorLotlc*
Totol eUvUod »r « •

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


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
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
Medium Low None 6
Low Medium High 10
2-5 5-10 greater man 10 7
Flberglass-PVC Protected Steel Unprotected Steel 10
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
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 «>
Agricultural Ccnmercial or Residential 5

D.  Distance to Installa-
   tion boundary

E.  Critical environments
   (within I  mile radius)
                        Greater than 2 miles     I to 2 miles
                        Not a critical
F.  Ground Hater use of
    designation of nearest
    surface water body
Groundnater use of
uppermost aquifer
                        Agricultural or
                        industrial use.
Not used, other
sources readily
 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
                    1,001 feet to I

                    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
Potable water supplies
Drinking water, no muni-
cipal water available;
commercial, industrial,
or irrigation, no other
water source available.

Greater th