Urittd!
         Env«onmenm Protection
         Agency
Office of Policy. Planning
and Evatoatan
EPA/230-10-88-041
November 1988
         Review of
         Ecological Risk Assessment
         Methods
Exposure
                  Hazard
                                      Risk Characterization
   Receptor

-------
  REVIEW OF ECOLOGICAL RISK ASSESSMENT
                 METHODS
               Prepared By:

 Sue Norton,  Margaret McVey, Joanne  Colt
        Judi Durda, Robert Hegner

             IGF  Incorporated
             9300 Lee  Highway
        Fairfax,  Va.   22031-1207
              Prepared For:

             Dexter Hinckley
Office of Policy Planning and Evaluation
  U.S. Environmental  Protection Agency
              401 M St.  SW
         Washington, D.C.   20460
              November 1988
                U.S. Environmental Protection Agency
                Region 5, Library (PL-12J)
                77 West Jackson Boulevard, 12th floor
                Chicago, !L  60604-3590

-------
                                   DISCLAIMER

 This is a contractor's final report, which has been peer reviewed by the EPA
 Offices and other contractors as described in the Acknowledgments.  The
 contents of this document do not necessarily reflect the views and policies of
•the U.S. Environmental Protection Agency, nor does mention of trade names or:'
 commercial products constitute endorsement or recommendation for use.

-------
                            ACKNOWLEDGMENTS
    Special acknowledgments are due to the reviewers of the draft report
who provided valuable comments and suggestions as well as specific
recommendations for the future use of ecological risk assessment in
regulatory agencies.  In particular, we would like to thank Dr. Donald
Rodier of the EPA Office of Pesticides and Toxic Substances,
Environmental Effects Branch, Washington, D.C.; Dr. Ossi Meyn of the EPA
Office of Solid Waste and Emergency Response, Health Assessment Section,
Washington, D.C.; Dr. J. Garner of the'EPA Environmental Criteria and
Assessment Office in Research Triangle Park, North Carolina; Dr. Thomas
Barnwell, Jr., of the EPA Office of Research and Development (ORD),
Environmental Research Laboratory, in Athens, Georgia; Dr. Kenneth Perez
and Dr. Allan Beck of the EPA/ORD -Environmental Research Laboratory in
Narragansett, Rhode Island; Dr. Gerald Niemi of the EPA/ORD
Environmental Research Laboratory in Duluth, Minnesota; Dr. Steven
Lutkenhoff and Mr. Randall Bruins of the EPA/ORD Environmental Criteria
and Assessment Office in Cincinnati, Ohio; Dr. Denise Steurer of the EPA
Region V Water Quality Branch; Dr. Lawrence Barnthouse of the Oak Ridge
National Laboratory; Dr. Thomas Hallam of the University of Tennessee at'
Knoxville; Dr. John Conroy of COMECO; Mr. Dennis Logan of Marine
Ecological Research, Inc.;  Ms. Carolyn Fordham of Environmental Science
and Engineering, Inc.; Dr.  Patrick Sheehan of Aqua Terra Technologies;
and Dr. William Lappenbusch of Lappenbusch Environmental Health,
Incorporated.

-------
                           TABLE OF CONTENTS


 Section                                                  Page

 EXECUTIVE SUMMARY  	   1

 1.0  INTRODUCTION   	   4

     1.1  Purpose of the Report  	   4

     1.2  General Approach and Scope 	   4

     1. 3  Definitions  	  10

     1.4  Organization of the Report	  10


 2.0  DISCUSSION AND CHARACTERIZATION OF METHODS 	  12

     2 .1  Obj ective of Methods .	  12
                                                                       i:
     2.2  Types of Methods and Applicability to Objectives .  13
         2.2.1  Qualitative vs.  Quantitative Methods 	  14
         2.2.2  "Top-down" vs.  "Bottom-up" Methods 	  19

     2.3  Technical Characteristics	  21
         2.3.1  Definition of Receptors and Endpoints 	  21
         2.3.2  Degree of Integration of Information
                Concerning Multiple Chemicals
                and Pathways  	  25
         2.3.3  Treatment of Uncertainty 	  26

 3.0  CONCLUSIONS AND RECOMMENDATIONS 	  31

     3.1  Conclusions  	  31
     3. 2  Recommendations 	  32

GLOSSARY 	  35

REFERENCES  	  40

APPENDIX A:  Framework for Review of Legal Mandates
             and Ecological Assessment Methods

APPENDIX B:  Legal Mandates for Ecological Assessment

APPENDIX C:  Ecological Assessment Method Summaries

-------
                             LIST OF TABLES

Number                                                      Page


1.  Statutes, Directives, and Associated Methods
    Reviewed  	  6

2.  Additional Methods Reviewed  	  9

3.  Guide to Methods Reviewed in Appendix C  	 11

4.  Possible Endpoints for Ecological
    Risk Assessment	 22
                            LIST OF FIGURES


Number                                                       Page

1.  An Integrated Model of Ecological Risk
    Assessment 	   5

2.  Quotient Method 	  15

3.  Dose-Response Method  	  16

4.  Extrapolation from Laboratory to Field  	  23

5.  Uncertainty and Data  Extrapolation  	  26
                                   111

-------
               REVIEW OF ECOLOGICAL RISK ASSESSMENT METHODS
                             KXJKUT.LVE SUMMARY
    This document reviews several existing methods for conducting
 ecological assessments to support regulatory decision-making.  Ecological
 risk assessment, strictly defined, is a procedure that predicts the
 probability of adverse effects to ecosystems, or parts of ecosystems, from
 environmental pollution.  However, the term is often used to encompass many
 types of ecological assessment procedures being used by EPA to support
 regulatory decision-making.  The methods covered in our review include
 those that meet the strict definition of ecological risk assessment, as
 well other types of methods used by state and Federal agencies.  Overall,
 ecological assessment methods reviewed in this document have been developed
 for three major purposes: priority-setting, developing standards or
 guidelines, and as input to risk management decisions.  These methods are
 in a constant state of flux, as existing methods are refined, new methods
 are developed, and the data base needed to support the methods continues to
 grow.                                                                     :"

    The purpose of this document is to identify general trends and
 limitations of ecological assessment as it is currently practiced.  We
 reviewed 20 ecological assessment methods that have been used or are ready
 to be implemented, and that we consider representative of ecological
 assessment methods developed by EPA and other Federal and state agencies.
 We have focused on methods designed to predict the likelihood and magnitude
 of adverse effects that can result from releases of toxic or hazardous
 substances into the environment, although several techniques for the
 assessment of ecological damage are also included.  Each method was
 reviewed using a framework that we developed to ensure consistency  among
 the reviews.  The framework consists of a set of characterization points in
 each of the four major components of the ecological risk assessment
 process: receptor characterization, hazard assessment, exposure assessment,
 and risk characterization.  We also reviewed the legislative mandates  under
which the methods were developed, as well as the resources  (data, cost,
 level of expertise) needed to implement the methods.

    Most of the methods included in our review are quantitative  in  nature,
although several were qualitative.  The qualitative approaches can  be  used
 to evaluate problems for which little quantitative information is
available,  and can be effective for setting priorities, either as  ranking
or screening procedures.  They are generally less resource-intensive than
quantitative methods.  Nevertheless, qualitative approaches are  generally
not suitable for developing standards or managing risks;  for these
applications,  a quantitative approach is superior.

-------
    The quantitative methods included in our review can be  categorized  into
quotient methods (those that provide a "yes/no"  estimate  of risk) and
continuous methods (those that provide an exposure-dependent estimate of
risk).   Quotient methods are generally easily implemented,  rely  on  readily
available data, and are well-suited for priority-setting  and developing
standards.  Risk management decisions generally  require the more complex
and realistic continuous methods that provide an exposure-dependent
probabilistic estimate of risk.   The continuous  methods can be used for
priority- and standard-setting as well.  The most significant drawback  to
the use of continuous methods is that exposure-.response data are not
available for many pollutant/receptor combinations.

    We found that the ecological assessment methods vary  substantially  with
respect to the receptors and endpoints evaluated.  Most of the methods
address risks to populations rather than to communities or ecosystems,  and
the endpoint of concern is often death, although reduced  growth  and
reproduction are also considered.  This is primarily because data are  often
insufficient to support risk assessment at the community  and ecosystem
levels.  For example, exposure-response data using community-level
endpoints such as species diversity are extremely limited.  Exposure-
response data on population-level responses can be used to predict effects
at higher levels (i.e., a "bottom up" approach), but there is considerable
uncertainty associated with these types of predictions.

    There are also differences among the methods in terms of their
treatment of uncertainty.  Methods that rely on professional judgment do
not explicitly address uncertainty.  A common way to treat uncertainty is
through the use of safety or assessment factors based on data adequacy;
this approach is often applied in methods used to set priorities or to
develop standards.  Most of the risk assessment methods that incorporate
exposure-response information attempt to address uncertainty in both uhe
exposure and risk estimates.  The techniques used  include  statistical
confidence limits, Monte Carlo simulations, sensitivity analysis,  and  field
validation and calibration.

    We found that there are many trade-offs inherent to  the  ecological
assessment process.  For example, the more  realistic the method, the less
likely it is that adequate exposure-response data  are available, and the
more difficult it becomes to propagate sources of  uncertainty throughout
the analysis.  Currently, the most  realistic models used for probabilistic
risk assessment require inputs for biological parameters  for which few
supportive data exist.  Although the more complex  analyses may  more closely
approximate real-life conditions, their application may  be limited by  the
lack of supporting data and high operational  resource requirements.  On  the
other hand, users of the more simple methods  might not be aware of the
underlying assumptions that tend to  limit  the applicability of  these
approaches.

    Based on our review of  the  20 ecological  assessment  methods, ICF and
the reviewers of our draft  repc :t have several  recommendations:

-------
Government-sponsored ecological damage assessments (field
investigations conducted to assess existing ecological damage)
provide an excellent opportunity for collecting data on the
relationship between pollutant levels and ecological damage.  Agency
program offices should coordinate their efforts in this regard  to
take full advantage of this data source.

Additional laboratory and field research is needed in several areas:
the interactions between stressors; sublethal effects; uncertainties
associated with extrapolation of laboratory data to the field;  and
modeling of population responses to pollutants considering density-
dependent population interactions.

More emphasis should be placed on exposure-response evaluation, with
less emphasis on identifying "no effect levels" based on hypothesis
testing.  In addition, more emphasis should be placed on statistical
treatment of uncertainty.

Endpoints should be chosen based on ecological, societal, and
regulatory significance as well as on data availability.  Although
endpoints such as species diversity, altered nutrient cycling,  and
ecosystem resilience may be more significant ecologically than
endpoints such as mortality, theoretical constraints and the lack of
exposure-response data currently limit the applicability of         :'
ecosystem-level endpoints to most problems.

-------
                             1.0  INTRODUCTION
 1.1  PURPOSE OF THE REPORT

    This report reviews several existing methods developed by EPA and other
 Federal and state agencies for assessing ecological impacts or risks
 associated with the release of toxic or hazardous substances into the
 environment.  The purpose of this report is to identify general trends and
 limitations of ecological assessment methods as they are currently
 employed.  This document is not intended to provide a step-by-step approach
 for conducting ecological assessments, but to provide a baseline
 understanding of the processes and general applications of ecological
 assessment methodologies.

 1.2  GENERAL APPROACH AND SCOPE

    We reviewed several existing ecological assessment methods to identify
 technical approaches to ecological assessment and to place these approaches
 in the context of solutions to- particular needs, such as developing
 standards or establishing testing priorities.  To ensure a consistent
 approach to each review, we developed a framework for the description of  . •.
 each method.  Our reviews were structured to address the four basic
 components of ecological risk assessment illustrated in Figure 1:   (1)
 receptor characterization, (2) hazard assessment, (3) exposure assessment,
 and (4) risk characterization.  We also described the operational resources
 (e.g., cost, level of expertise) required to implement each approach.

    Our review is limited to methods that we consider representative of
 those in use by state or Federal agencies, or methods that are ready to be
 implemented; we do not include those that are still experimental.  We focus
 on methods designed to predict the possibility or probability of adverse
 ecological impacts.  Methods designed to quantify existing damages  or those
 used to model exposure are included only in terms of their contribution to
 predicting adverse ecological effects.

    To understand the methods in the context of their intended application,
we also review the legislative or executive directives, under which  the
methods were developed.  Table 1 shows the legislative mandates  considered,
 the methods developed under each, and a brief summary of  the purpose of
each method.  Some of the methods covered in this document were  not
developed under any specific legislative mandate, but are  included  because
 they were developed for EPA use or had been used by EPA offices;  these  are
presented in Table 2.  For simplicity, we refer to methods  in  this  report
by the government office for which the method was prepared.  The exceptions
 to this are some of the methods which were not developed  under

-------
                                                                                                   Hazard
Exposure
                ..How much it released?
                        For how long?
                                 How tar does it go?
                                  T«n.fo,ma«on
                                        r
                                        L
 Where does it end up?
                       How toxic is it
                        to different
                          species?
                        Life stages?
                    How does length
                        of exposure
                      affect toxicily?
                                                                                       How do other
                                                                                       factors affect
                                                                                           loxicily?
                                                                                                     Toiicity
J
                                                                                                   Chronic/Acute
                                     Modifying
                                      factors
tow much for
how long?

' Dose *" R««P

onse
                                                     Habitat
                                                              £ Whi
    Trophic Level


where do they live?     Risk Characterization
                                   Life Stagu
                                                 How are eggs, juveniles, adults different?
                  Species    I What are the communities ol concern?
      Receptor
                                     FIGURE 1.   AM IMTBGRATED MODEL  FOK ECOLOGICAL RISK ASSESSMENT

-------
HEIHOO NO
               SIAIUIE 0« DIRECTIVE
                                             TABLE  1:   SIAIUIES.  DIRECTIVES. AND ASSOCIATED METHODS REVIEWED


                                                    MANDATE                                        METHOD
      Legislation Administered by EPA

   1-    Comprehensive Environmental
         Response,  Compensation, and
         Liability Act (CERCIA.
         including the 1986 amendments)

   2
         Clean  Air  Act
                                    to establish  a  National  program for
                                    responding  to releases of  hazardous
                                    substances  into the environment.
                                            To protect  and enhance the quality
                                            of the Nation's air resources through the
                                            prevention  and control of air pollution.
                                                                                                                                             BRIEF DESCRIPTION OF OBJECTIVE
                                                Measuring Damages to Coastal and Marine
                                                Environment Natural Resources  (DOI
                                                1987a>
                                             To  establish procedures for assessing
                                             damages to natural resources from a
                                             relatively small discharge of oil or a
                                             release of a hazardous substance.

                                             To  establish procedures for assessing
                                             damages to natural resources from a
                                             relatively large discharge of oil or a
                                             release of a hazardous substance.

Review of  the National Ambient Air           To  assess the risks of ozone to human
Quality Standards  for Ozone  (EPA/OAR  1986)   welfare.
                                                                                            Natural Resource Damage Assessments.
                                                                                            Final Rule (for Type I Assessments)
                                                                                            (DOI 1987b)
                                                                                            An Assessment of the Risk of Strato-
                                                                                            spheric Modification (EPA/OAR 1987)
                                                                                                                               To assess the ecological impacts of
                                                                                                                               chemicals that modify the stratosphere.
         Clean UJtcr  Act (including
         the Water  Quality Act of 1987)
                                   To restore and maintain  the chemical,
                                   physical, and biological  integrity of
                                   the Nation's waters.
   9-
  10-
  11
federal  Insecticide,
Fungicide,  and Rodenticide
Act (FIFRA)
lo prevent "unreasonable adverse effects
on the environment" from the misuse  of
pesticides.
                                                Guidelines for Deriving Numerical
                                                National Water Quality Criteria for the
                                                Protection of Aquatic .Organisms and their
                                                Uses (EPA/OURS 1986)  .
                                                                                            An Approach to Assessing Exposure to
                                                                                            and  Risk of Environmental Pollutants
                                                                                            (EPA/OURS 1983)

                                                                                            Water Quality-Based Permitting for Toxic
                                                                                            Pollutants (EPA/OURS 198S, 1987)
                                                                                            Biological Criteria for the Protection
                                                                                            of Aquatic Life (Ohio EPA 1987a,b,  1988)
Nigara River Biota Contamination Project:
Fish Flesh Criteria for Piscivorous
Wildlife (NYS/OEC 1987)

Standard Evaluation Procedure for
Ecological Risk Assessment (EPA/OPP 1986)
                                                                                   Chemical Migration Risk  Assessment
                                                                                   (Onishi et  al.  1982,  1985)
To standanze a method for  deriving
guidelines for chemical  concentrations
consistent with the protection of
aquatic organisms,  human health and
some recreational  activities.

To provide guidelines  for conducting
risk assessments for waterborne
pollutants.

To provide guidelines  for  issuing National
Pollutant Discharge Elimination System
(NPOES) permits.

To standardize collection and use of
biological measures of surface  water
quality.

To develop limits  for  fish  tissue residues
levels protective  of fish-eating wildlife.
To outline procedures to assess risk of
pesticide uses proposed for registration.
                                                                                            To predict the occurrence and duration
                                                                                            of pesticide concentrations in surface
                                                                                            receiving agricultural  runoff and
                                                                                            to predict the potential  damage to  aquatic
                                                                                            biota.

-------
                                                       TABU 1:  STATUTES. DIRECTIVES. AND ASSOCIATED METHODS REVIEWED (continued)
METHOD NO.
                 STATUTE  00 DIRECTIVE
                                                               MANDATE
                                                                                                              METHOD
                                                                                                                                              BRIEF DESCRIPTION OF OBJECTIVE
  12-
  13
  U
           Marine  Protection and
           Resources  Sanctuaries Act
           Resource Conservation and
           Recovery Act  (RCRA)
To regulate the disposal of waste  in the
ocean in order to protect human health.
welfare, and amenities, and the marine
environment, ecological systems, and
economic potentialities.

To promote the protection of health and
the environment and to conserve valuable
material and energy sources.
            Safe  Drinking Water Act
            Toxic  Substances Control Act
            (ISCA)
To assure that all public drinking water
systems provide safe, high quality water.

To protect human health and the
environment through the regulation of the
manufacture and use of chemicals.
  16-
We have not identified any methods
developed under this legislation.
Potential for Environmental Damage:
Proximity of Mine Waste Sites to Sensitive
Environments (EPA/OSW 1987a)

Technical Resource Document for
Risk-based Variances from the Secondary
Containment Requirement of Hazardous
Uaste Tank Systems.  Volume II:
Risk-based Variance. (EPA/OSU 1987b)

The RCRA Risk-Cost Analysis Model,  Phase
III Report (EPA/OSU 1964)
We have not identified any methods
developed under this legislation.

Estimating "Concern Levels" for Concen-
trations of Chemical Substances in the
Environment  (EPA/OTS 1904)
                                               Ecological Risk Assessment in The
                                               Office of Toxic Substances:  Problems and
                                               Progress 1984-1987 (EPA/OTS 1987)
To aid in screening different mining
activities for potential environmental
impacts.

To determine environmental risks posed
by the release of uaste constituents
from hazardous waste tanks.
                                                                                           To aid in designing regulations
                                                                                           governing hazardous waste treatment
                                                                                           that are protective of human health and
                                                                                           the environment.
To aid in the evaluation of premanu-
factunng notices for new chemicals
which may or  may not be toxic or
released into the  environment.

To define potential hazards posed by
toxic chemicals.
       Legislation Administered by Other agencies
           Coastal  Zone Management Act
           of  1972
            Endangered Species Act
            Executive Order 11988,
            Hoodplam  Management
To encourage and assist States to develop
and implement mangement programs to
protect the land and water resources
of the coastal zone.

To conserve the ecosystems upon which
endangered or threatened species depend.
and to conserve the species themselves.

Requires that federal agencies take actions
to reduce the risk of flood loss, and  to
restore and preserve the natural and
beneficial values served by floodplains.
We have not identified any methods
developed under this legislation.
We have not identified any methods
developed under this legislation.


We have not identified any methods
developed under this legislation.

-------
HE 1 HOD NO.
                STATUTE  Oft DIRECTIVE
         I ABLE 1:  SIAIUltS, DIRECTIVES. AND ASSOCIAUD METHODS REVIEWED (continued)



                 MANDATE                                        METHOD
                                                                                                                                             BRIEF DESCRIPTION Of OBJECTIVE
           Executive Order 11990,
           Protection  of  Wetlands
           fish and Wildlife
           Coordination Act
Requires that federal agencies take actions
to minimize the destruction, loss, or
degradation of wetlands, and to preserve
and enhance the natural and beneficial values
served by wetlands.

To assist in developing and protecting all
species of wildlife, wildlife resources, and
wildlife habitat.
           National  Environmental Policy Act lo preserve and enhance the environmental
           (NEPA)                             quality of the Nation.
           Wild  and Scenic Rivers Act
To preserve selected rivers in their
free-flowing condition, to protect the
water quality of such rivers,  and to
fulfill other vital national conser-
vation purposes.
We have not identified any Methods
developed under this legislation.
We have not identified any methods
developed under this legislation.
We have not identified any methods
developed under this legislation.

We have not identified any methods
developed under this legislation.
CO

-------
                                                                           TABLE  2

                                                                  ADDITIONAL  METHODS REVIEWED
                       METHOD NO
                        METHOD
      BRIEF DESCRIPTION OF  OBJECTIVE
v£>
17-    Methodology for Environmental Risk
       Analysis (Barnthouse 1982); Users Manual
       for Ecological Risk  Assessment
       (Barnthouse et al. 1986)

18-    Regional Ecological Assessments:  Concepts,
       Procedures and Application  (Ballou et al.
       1981)
                                                                                    To support  EPA/ORD's  synfuels  research
                                                                                    program by  developing an environ-
                                                                                    mental  risk assessment methodology.
To discuss the approaches developed
at Argorme National Laboratory to
conduct regional ecological assessments
for the impacts of alternative energy
opt i ons.
                          19-     Computer  Simulation Models of  Assessment
                                 of  Toxic  Substances (Eschenroeder et al.
                                 1980)
                          20-     Unfinished Business:   A Comparative
                                 Assessment of  Environmental  Problems
                                                          To develop a comprehensive chemical
                                                          fate and transport simulation model
                                                          which includes transport through the
                                                          biotic environment.

                                                          To estimate and rank current ecological
                                                          risks posed by 31 environmental problems.

-------
 any  specific legislation.  More detailed information describing authors is
 given, when available, in Appendix C and in the references.   A quick
 reference guide to Appendix C is provided in Table 3.

 1.3  DEFINITIONS

     Because ecological impact and risk assessment are still emerging
 fields, a wide variety of terms and definitions have been used to describe
 different types of analyses.  In this document, we use the term "ecological
 assessment" to refer to any type of assessment related to actual or
 potential ecological effects resulting from human activities.  The term
 therefore encompasses impact, risk, and damage assessments as well as the
 establishment of environmental criteria based on ecotoxicology.

     The phrase "ecological risk assessment" is commonly used to cover this
 array of analyses.  In strict usage, however, ecological risk assessment is
 a quantitative procedure that estimates the probability of specified levels
 of ecological effects occurring in an ecosystem or part of an ecosystem in
 response to a perturbation, and relates the magnitude of the impact to the
 perturbation.  In order to distinguish this more strict usage of the word
 "risk," we refer to this latter type of analysis as  "ecological risk
 assessment" in this document and to all other analyses as "ecological     a
 assessments."

 1.4  ORGANIZATION OF THE REPORT

    The remainder of this report presents the major  findings of our review.
 In Section 2.0, we discuss the general purposes of ecological assessments
 and  the approaches currently used.  We discuss our general conclusions and
 recommendations for future developments in the area  of ecological risk
 assessment in Section 3.0.  A glossary that includes terms used in  the text
 and appendices follows the text.  Appendix A describes our approach to
 reviewing the different methods and presents the framework used for each
 review.  Appendix B summarizes the requirements of 15 legislative or
 executive directives for ecological assessments.  Finally, Appendix C
presents the results of our detailed discussion of each method.
                                      10

-------
                                  TABLE 3

                        GUIDE TO METHODS REVIEWED
                               IN APPENDIX C

Method No.                         Method	Pages

 1 -  CERCLA Type A Damage Assessment (DOI 1987a)	   C- 2-  9

 2 -  CERCLA Type B Damage Assessment (DOI 1987b)	   C-10-13

 3 -  Ozone Staff Paper (EPA/OAR 1986)	   C-14-16

 4 -  Stratospheric Modification (EPA/OAR 1987)	   C-17-21

 5 -  Ambient Water Quality Criteria (EPA/OWRS 1986)	   C-22-24

 6 -  Approach to Exposure and Risk ^EPA/OWRS 1983)	   C-25-27

 7 -  Water Quality-based Permitting (EPA/OWRS 1985, 1987)	   C-28-31

 8 -  Biological Criteria (Ohio EPA 1987a, 1987b,  1988)	   C-32-38

 9 -  Niagara River Fish Flesh Criteria (NYS/DEC 1987)	   C-39-41'

10 -  Standard Evaluation Procedure for Ecological Risk
      (EPA/OPP 1986)	   C-42-46

11 -  Chemical Migration Risk Assessment
      (Onishi et al. 1982, 1985)	   C-47-51

12 -  Proximity to Sensitive Environments (EPA/OSW 1987a)	   C-52-53

13 -  HWT Risk-based Variance (EPA/OSW 1987b)	   C-54-56

14 -  RCRA - Risk Cost Analysis Model (EPA/OSW 1984)  	 C-57-60

15 -  Estimating Concern Levels (EPA/OTS 1984) 	 C-61-62

16 -  Ecorisk in OTS (EPA/OTS 1987)  	 C-63-66

17 -  Users' Manual for Eco. Risk (Barnthouse et al.  1982, 1986).. C-67-78

18 -  Regional Ecological Assessments (Ballou et al.  1981)	 C-79-86

19 -  Computer Simulation Model (Eschenroeder et al.  1980)	 C-87-88

20 -  Comparative Risk Project  (EPA/OPPE 1987) 	 C-89-92
                                      11

-------
                         2.0  DISCUSSION OF METHODS
    In this section, we discuss the major findings of our  review.  In
Section 2.1, we identify several objectives of ecological  assessments, and
provide examples of methods developed for each objective.   In  Section  2.2,
the methods are grouped broadly by the type of approach used.   Finally,  the
technical content of each method is discussed in Section 2.3.

2.1  OBJECTIVES OF METHODS

    All of the methods included in our review were developed to assess the
potential for adverse effects on ecosystems or parts of ecosystems  from  the
release of hazardous substances into the environment.  Within this  overall
intent, however, the methods were developed for several practical
applications.  The objectives of an ecological assessment method depend,  in
part, on the legal mandate under which the method was developed.  Most of
the legal mandates require consideration of "human health and the
environment".  However, some mandates more specifically request the
development of standards or guidelines to limit concentrations of hazardous
substances in the environment (e.g., the Clean Water Act specifies  the
"development of federal water quality criteria").  In other situations    -.-
(e.g., energy development, pesticide use), adverse ecological effects  must
be weighed against the benefits to human welfare.  In these cases,  a
quantitative ecological risk assessment may be used for comparing
incremental costs and benefits.  Prioritization schemes have been developed
to aid decision makers in narrowing the large scope of regulatory concerns
and to target situations that require more testing or research.

    The specific objectives of each method are summarized in Tables 1
and 2.  In general, we found that most methods have one of three
objectives: (1) to set priorities,  (2) to support the setting of standards
or guidelines, and (3) to assess risk as input to risk management
decisions.  While some of the methods were developed specifically for one
of these objectives, several of them could be easily applied to more  than
one objective.

    Several of the methods included in our review are ranking  schemes used
to set priorities.  For example, the Comparative Risk Project  (EPA/OPPE
1987) ranks broad environmental problems.  The RCRA  Risk-Cost  Analysis
Model (EPA/OSW 1984) scores hazardous waste treatment,  storage,  and
disposal technologies with respect  to their relative potential for
producing adverse ecological impacts.  Other  ecological assessment methods
have been used as screening procedures to  identify priorities  for further
testing or research.  For example,  the Standard  Evaluation  Procedure  (SEP)
for Ecological Effects (EPA/OPP 1986) and  the Method for  Estimating Concern
Levels (EPA/OTS 1984) identify chemicals which,  by  their  projected pattern
of release into the environment, are of  sufficient  ecological  concern to
merit further testing.  The Approach for Assessing  Exposure and Risk
developed by EPA/OWRS (1983) describes a method  of  identifying combinations

                                      12

-------
of plant and animal species, exposure levels,  and projected effects on a
site-specific basis that are of sufficient ecological  concern to  merit
further investigation.  Similarly,  EPA/OSW (1987a) screened mine  sites for
the potential to adversely affect valuable ecosystems  based on to their
proximity to sensitive habitats.   One well-known priority setting method
that we did not review is the Hazard Ranking System (MRS),  which  is used  to
select sites for the Superfund National Priorities List.   This is because
the current version of the system has a very limited ecological assessment
component, and the proposed revisions are not available for public comment
at the time of this publication.

    Several of the methods reviewed were developed to assist in setting
standards or guidelines to limit releases of chemicals into the
environment.  The Ambient Water Quality Criteria methodology has  been used
to set guidelines for limiting ambient pollutant concentrations in surface
water to be protective of aquatic life.  The Water Quality-based  Permitting
for Toxic Pollutants (EPA/OWRS 1985, 1987) approach establishes guidelines
for using whole-effluent toxicity tests to establish effluent discharge
limits.  In the Ozone Staff Paper (EPA/OAR 1986), EPA estimated
concentrations of ozone in the atmosphere that should be protective of
agricultural plants and forests.   As an approach to calculating acceptable
release levels of chemicals, the EPA/OTS (1984) method to estimate Concern
Levels identifies concentrations of chemicals that may cause adverse     . :
environmental effects in aquatic populations.  The NYS/DEC (1987) used the
Niagara River Fish Flesh Criteria methodology to set limits for contaminant
residue levels in fish that would be protective of piscivorous animals such
as mink and osprey.

    Most of the remaining methods were developed to conduct risk
assessments to support management decisions (e.g., Onishi et al.   1985,
EPA/OSW 1987b, EPA/OAR 1987).  Of these, only the Land-Use Disturbance
portion of the Regional Ecological Assessments method  (Ballou et  al. 1981)
and the Stratospheric Ozone analysis (EPA/OAR 1987) evaluates risks
associated with agents other than toxic chemicals.  The User's Manual for
Ecological Risk Assessment (Barnthouse et al. 1986) includes  several
methods that can be used to support standard and priority setting as well
conducting quantitative risk assessments.

    Three of the methods included in our review assess existing  ecological
impacts.  The Type B damage assessment  (DOI 1987b)  includes  methods  to
measure ecological damages that have already occurred.   Although damage
assessment is not the focus of this report, these methods  can provide
information that can be used as a baseline  for predictive  risk assessment,
and can offer insight into the appropriate  receptors,  endpoints,  and
exposure pathways to be used in risk assessment.  The  Type  A damage
assessment procedure (DOI 1987a) was developed to estimate damage, but can
be applied to predicting the occurrence of  adverse  effects.   The Ohio  EPA
(1987a, 1987b, 1988) Biological Criteria and evaluation  methodology
includes measurements of fish and macroinvertebrate sub-communities  that
reflect the biological integrity of aquatic ecosystems.
                                      13

-------
     Other methods,  such  as Regional Assessment Units (Ballou e_t al.  1981),
 were developed to provide a common basis for discussion and are included in
 our review only in  the context of their contribution to risk assessment.

 2.2  TYPES OF METHODS AND APPLICABILITY TO OBJECTIVES

     In this section, we  discuss the general types of methods reviewed,  some
 of  the strengths and weaknesses of each, and their suitability for the
 objectives discussed above.

 2.2.1  Qualitative  vs. Quantitative Methods

     Although most of the methods reviewed are based on quantitative
 analyses,  several use qualitative analyses, as discussed below.

     Qualitative Methods.  One of the qualitative methods described in
 Ballou eg al.  (1981) was designed to-identify potential conflicts in
 implementing certain energy resource development scenarios by delineating
 endangered and threatened species habitat.  The EPA/OSW (1987a) used a
 similar approach in "Proximity of Mine Waste Sites to Sensitive
 Environments".  In  this  analysis, mine sites in different raining segments
 were  identified as  posing more or less of a threat to highly valued
 environments  based  on their proximity to endangered species habitats,      "
 wetlands,  and National parks and forests.

    Two of the  qualitative methods, EPA/OPPE (1987) and EPA/OWRS (1983) use
 professional  judgment to evaluate ecological effects.  The Comparative Risk
 Project (EPA/OPPE 1987)  used professional judgment to broadly rank a large
 diversity  of  environmental problems.  Similarly, in the OWRS approach to
 exposure  and  risk (EPA/OWRS 1983), a great deal of professional judgment is
 used  to identify specific surface water locations that should be further
 investigated  because of  a high potential for adverse ecological effects.

    The strength of qualitative approaches is that chey can be used  to
 evaluate  effects and problems for which there is little quantitative
 information.    By using  professional judgment, many levels of  information
 can be  integrated into the decision-making process.  The qualitative
 methods included in our  review illustrate that these methods can be  used
 effectively  to  set  priorities, either as screening or ranking  procedures.
 Qualitative methods, however, are limited in their use for either
 developing standards or  managing risks.  The effort required to  implement
 qualitative methods can  be low relative to quantitative computer-based
 models.  However, if the methods that rely on professional judgment  are  to
 yield useful  results, the assessors must be highly skilled.

    Quantitative Methods.  The quantitative methods reviewed can be
categorized as  quotient  or ratio methods  (illustrated  in  Figure  2)  and
continuous or exposure-response methods (illustrated  in Figure 3).
                                      14

-------
                                             FIGURE 2

                                         QUOTIENT METHOD
                                     IF
                    - 1, regulate.
                        100%
                     Mortality
           Response
           (percent)
                          50
no effect
                                             LC
                                                60/AF
                           LC
                                                                90
Assessment
  Factor
                                                                  •Meet
                                             Concentration
Figure 2.  One use of the quotient method is to compare  an estimated environmental
concentration (EEC) to a toxicity benchmark (e.g.,  LC^Q).  Generally a few percent
mortality is considered acceptable,  and the 1X50 is multiplied by an assessment factor  (AF)
to estimate the level above which more  than a few percent mortality would occur.   If  the
EEC/LCtjQ x AF equals or exceeds  1,  then a decision  to  regulate the chemical or to
investigate the situation more  tully is made.

-------
                                          FIGURE 3

                                  EXPOSURE-RESPONSE METHOD
                                                                                     100%
                                                                                     Mortality
                Response
                (percent)
                                                  Concentration

Figure 3.   In  the exposure-response method,  estimated environmental concentrations are used
to predict  the  level of response (e.g.,  40 percent mortality).   Confidence limits around
the exposure-response curve define the  uncertainty associated with  the predicted level of
response.

-------
    Quotient Methods:

    Quotient methods are used to determine whether or not a specified  level
of environmental contamination might be of ecological concern.   Reference
concentrations intended to be protective of a given receptor are
established and are compared with estimated environmental concentrations
(EECs).  For example, as illustrated in Figure 2,  an  "assessment factor"
(AF) can be applied to an acute LC$Q value* (solid vertical line,  Figure  2)
to estimate a reference concentration that is approximately equivalent to  a
LC^ value (dashed vertical line, Figure 2).  Environmental concentrations
that exceed the reference concentration are considered to have potential
adverse effects.

    Several of the methods that we reviewed use the quotient method,
including EPA/OPP's (1986) Standard Evaluation Procedure for Ecological
Risk Assessment, EPA/OTS's (1984) method for Estimating 'Concern Levels',
and EPA/OSW's (1987b) method of evaluating risk from hazardous waste tanks.

    Quotient methods provide essentially a "yes or no" determination of
risk and are therefore well-suited for screening-level assessments.   In
these cases, a decision concerning the level of risk that is considered
acceptable is required, but is contained within the derivation of a
reference criterion concentration.  For example, the AWQC method (EPA/OWRS
1986) assumes that 1 percent adult mortality is an acceptable acute effect
and that 5 percent of the species present in an ecosystem can suffer more
than 1 percent adult mortality without the expectation of adverse ecosystem
effects.

    The primary advantage of the quotient method is that it is a relatively
low cost, easily implemented method that often relies on data that are
readily available for many chemicals (e.g., *LC$Q, ID$Q values).
Consequently, quotient methods are well-suited for setting priorities as
well as for developing standards.

    A limitation of the quotient method is that it does not predict the
degree of risk or magnitude of effects associated with specified levels of
contamination.  This is a minor limitation when setting standards or
priorities.   Some of the methods, however, attempt to address this problem;
these can be called "modified quotient methods."  In Barnthouse  et al.'s
(1986) Quotient Method and in EPA/OSW's (1987) Risk-based  Variance
procedure, the conclusions are expressed as  "no concern",  "possible
concern", and "high concern", depending on whether the ratio  of the
     *• An LC5Q value is the concentration of  a  substance  in  water  that  is
associated with the death of 50% of  the  organisms  in  a  laboratory  bioassay.
This notation is also used to describe other  proportions;  for instance,
refers to the concentration estimated to kill 1 percent of the test
organisms.  Similarly, an LD^Q value is  the dose (usually expressed as
mg/kg body weight) that is estimated to  kill  50 percent of the test
organisms.

                                      17

-------
 estimated environmental concentration  (EEC) to the reference concentration
 is <0.1,  0.1 to <10,  or >10,  respectively.  Another modification of the
 quotient  method was  used by Onishi  et  aj..  (1985); in this method, EECs were
 compared  to Maximum  Acceptable Toxicant Concentrations (MATCs)^ and LC5QS.
 If the EEC was below the MATC, the  fish population was considered "safe".
 If the EEC was above the LC5Q, the  fish population was believed to be at
 risk of increased mortality.  If  the EEC was between the MATC and the LC5o,
 the fish  population  was considered  to  be at risk of sublethal effects.

     Exposure-Response methods:

     Exposure-response or continuous approaches are used to estimate the
 magnitude of effect  associated with an estimated exposure concentration.
 The full  exposure-response curve  is used to estimate risk.  For example,
 one could use an exposure-response  curve (illustrated in Figure 3) to
 estimate  the exposure concentration expected to produce 10, 20, 50, or  100
 percent reduction of a trout  population due to direct effects of a
 contaminant.

     Derivation of explicit risk estimates  for a given endpoint of concern
 requires,  at a minimum,  relating  estimated environmental concentrations  to
 exposure-response information.  An example of the use of exposure-response
 information to estimate population-level effects is Ballou et al.'s (1981)
 assessment of the effects on  crop productivity of atmospheric sulfur       ''
 dioxide released from fossil  fuel burning  plants.  In this approach,  the
 concentration of S02  at varying distances  from the emission source was
 modeled and compared  with dose-response data for SC^-induced reductions  in
 crop yields.   The estimated losses  in  crop productivity were then mapped
 spatially  to  provide  an estimate  of the areal extent and degree of crop
 reduction  with increasing distance  from the source of air emissions.

    The exposure-response approach  is  well-suited for situations in which
 an  estimate  of the magnitude  of risk estimated to occur is needed to
 support the  setting of a standard, or  in cases where a risk management
 analysis will  be conducted.   For  example,  the EPA/OAR (1986) used an
 exposure-response  approach to aid in setting standards.  Exposure-response
 data were  used to  estimate crop yield  reductions with increasing ambient
 ozone concentrations.   EPA/OAR selected a  10 percent reduction  in yield as
 the level  of  concern.   The selection of a  particular level of effect
 represents  a  risk management  decision.  The exposure-response approach
 allows  a decision-maker to choose a level  of concern based on economic  and
 human welfare  considerations  if necessary.  In this way, the exposure-
 response approach may  be  more useful for providing input to risk management
 decisions  than the quotient method.
     •
     * The MATC is the toxic chemical  threshold  concentration lying in a
range bounded at the lower end by  the  highest  concentration having no
effect (NOEL) and at the higher end by the  lowest  test concentration having
a significant toxic effect (LOEL)  in a life  cycle  or partial life cycle test

                                       18

-------
    The exposure-response approach has  also  been used, in the case of the
RCRA Risk-Cost Analysis Model (EPA/OSW  1984),  to aid  in setting priorities.
Thus, one of the strengths of this approach  is that it can be applied to
many purposes.  A limitation of the approach,  however, is that exposure -
response data are not available for many chemical/receptor combinations.

2.2.2  "Top-Down" vs. "Bottom-Up"  Methods

    Most of the dose-response or quotient methods  in  our review addressed
effects to individuals or populations.   There  are  two ways to approach the
evaluation of effects at the community  and ecosystem  level.  The  first
approach, called the "top-down" approach, directly assesses  changes  in
function and structure of communities and ecosystems  (e.g.,  alterations  in
species diversity or primarily production- rates).  The second approach,  the
"bottom-up" approach, uses laboratory data on  effects at lower  levels of
organization (e.g.,  mortality of individuals)  to model changes  at the
community or ecosystem level.

    Top-down Methods.  Several of the methods  reviewed could be called  top-
down methods.  These include EPA/OPPE's (1987) Comparative Risk Project,
the RCRA Risk-Cost Analysis Method (EPA/OSW 1984), EPA/OSWs (1987a)
Sensitive Environment analysis, Ballou e_£,al.'s (1981) Land-use Disturbance
and Endangered and Threatened Species,  and Ohio EPA's (1987a,  1987b, 1988)..
Biological Criteria methods.  Most of these methods  were used to aid in
setting priorities,  however, and none included an ecosystem-level exposure-
response analysis.

    One of the strengths of top-down approaches is that  they evaluate
changes in communities and ecosystems directly.  These changes, as opposed
to such effects as changes in the number of individuals  in the population
of a single species, are easily defended by decision-makers  as being
important.  However, at the present time, few data exist to directly
predict the effects of chemicals on ecosystem-level properties such as
structure and function.  More fundamentally,  there is no accepted
definition of "ecosystem health," in part because ecosystems are dynamic,
changing with environmental conditions as organisms adapt or adjust to
stress (EPA/OPPE 1987).  Thus, most of the predictive top-down approaches
that we reviewed either address habitat  alteration or are based  on
professional opinion.

    The Ohio EPA  (1987a, 1987b, 1988) Biological  Criteria and evaluation
methodology represents a top-down approach  to evaluating existing
ecological impacts.  The criteria are biological  indices based on several
measures of fish and macroinvertebrate community  structure  (e.g., species
diversity, species number)  that reflect  the biological integrity of aquatic
ecosystems.  In this case,  "ecosystem health" is  defined as the  value  of
the indices measured for "least impacted11 surface water bodies  in each  of
several ecoregions in  the state.

    The RCRA Risk-Cost Analysis Model  (EPA\OSW 1984) is an  example  of  a
top-down predictive  approach that  attempts  to be  quantitative.   In this
approach, a generic  ecosystem exposure-response curve  is  constructed,

                                      19

-------
 spanning concentrations corresponding to minimal effects on sensitive
 species at  the lower end to ecosystem-level catastrophic effects at the
 high end.   The curve was based on four studies in which an ecosystem-level
 exposure-response relationship could be constructed empirically.  Hence,
 there are many uncertainties associated with applying this curve to other
 chemicals or situations.

    Because of the lack of toxicological data available for directly
 evaluating  changes in communities or ecosystems, quantitative risk
 assessment  cannot currently be conducted in a "top-down" manner, with very
 few exceptions.  However, as illustrated by the methods we reviewed, top-
 down approaches can be used effectively in setting priorities.

    Bottom-up Methods.  Three of the methods included in our review  (DOI
 1987a, Eschenroeder e_t ai. 1980, Barnthouse et ai. 1986) could be called
 "bottom-up" methods.  These methods estimate community-level effects using
 computer models and laboratory data on the responses of individuals and
 populations to chemicals.  One of the strengths of bottom-up approaches is
 that they provide insight into the processes that transfer effects between
 different components of ecosystems (e.g., through a food web).  However,
 because these models require a great deal of site- and chemical-specific
 data, the bottom-up approaches are most useful in supporting risk
 management decisions on a site-specific basis.                             •'

    The theoretical constraints of the modeling approaches can be daunting.
 The ecological theory required to use system analysis to predict changes in
 communities and ecosystems from more basic information is still in  its
 infancy,  despite early recognition of its importance (Kickert and Miller
 1979).   Although the models that attempt to predict community responses
 using individual and population-level laboratory data illustrate the
 substantial progress that has been made in ecological risk assessment, they
may not incorporate (for practical or theoretical reasons) responses that
can greatly influence the conclusions drawn about risk.  At least one  of
 the three methods that model biotic community-level effects considers  each
of the following biotic community relationships:

    •  Transfer of energy and biomass from primary productivity through
       several trophic levels and transfer of coxicant-induced  reductions
       in productivity at one trophic level through successive  levels;

    •  Effects of reduced recruitment of juveniles to population age-
       structure,  productivity, and biomass;

    •  Transfer of toxicants through several trophic levels;  and

    •  Changes in respiration,  feeding, or grazing rates,  susceptibility to
       predation,  mortality, emigration, and fecundity  in  species  at one
       trophic level affecting species in successive trophic  levels.
                                      20

-------
However, none of the three methods appear to  consider other  important
factors influencing community response:

    •  Density-dependent population regulation (e.g., density-dependent
       changes in juvenile survivorship  compensating for mortality caused
       by pollution);

    •  Toxicant-induced changes in behavior (e.g.,  avoidance,  disrupted
       chemical communication among animals);  and

    •  Incorporation of biotic and abiotic stressors (e.g.,  parasites  and
       extreme weather, respectively)  and toxicant-induced changes  in
       responses to these stressors.

2.3  TECHNICAL CHARACTERISTICS

    We reviewed each ecological assessment method with  respect to five
broad factors: (1) receptor characterization,  (2) hazard  assessment,  (3)
exposure assessment, (4) risk characterization,  and (5) operational
resource requirements.   Our detailed framework for  reviewing the methods  is
presented in Appendix A, and the results of our review  of each method are
found in Appendix C.  In this section, we discuss four  major technical     ...
characteristics that appear to be particularly important  in determining the
scope and results of ecological assessment as it is currently practiced.
In general, the technical characteristics of ecological assessment methods
are similar for methods that were developed for similar objectives (e.g.,
setting standards) or that are based on the same general  type  of approach
(e.g., quotient method, exposure-response approach).  Therefore, we discuss
the technical characteristics of the methods in the context of the overall
objectives for which the methods were designed.

2.3.1  Definition of Receptors and Endpoints

    Receptors are the components of ecosystems that are or may be adversely
affected by a pollutant or other stress.  Endpoints are the particular
types of impact or potential impact a chemical or other environmental
stress has on a receptor (e.g., death, decreased growth or productivity).
Because of the complexity of natural systems, it is difficult to assess
potential impacts to all receptors for all endpoints.  Therefore,
ecological assessment methods select particular  types  of receptors and
endpoints to be "indicators" of potential harm to all  components of the
system.

    The range of potential indicators is enormous.  Table 3 presents  a list
of some potential endpoints for receptors at  the individual,  population,
community, and ecosystem level.  Although there  is  no  accepted  definition
of ecosystem "health",  some possible  indicators  of  ecosystem  resilience
(the ability of an ecosystem to recover  from  stress) include  measurements
of species diversity,  nutrient cycling,  and productivity  at the community
or ecosystem level  (Levin et al. 1983, NRC 1981, EPA/OPPE 1987).   Because
there is general consensus on adverse effects at the population level,

                                      21

-------
 (e.g., decreased reproduction or growth,  increased mortality),  the most
 appropriate endpoints for use in risk assessment at this  time  may be at the
 population level.

    Few of the methods reviewed selected receptors and endpoints based
 solely on ecological significance.  In fact, in most cases the selection  is
 driven by practicality, as the receptors and endpoints selected tend to be
 those for which the most toxicity data are available.  For example, most  of
 the methods assess aquatic receptors.  Part of the reason for  this  is  that
 there is generally less information on the exposure of terrestrial
 organisms, or on the toxic effects of chemicals to terrestrial organisms.
 The particular approaches to receptor and endpoint selection under  the
 various types of methods are discussed below.

    Methods Used to Develop Standards or Guidelines.  Of the ecological
 assessment methods used to develop standards, the most common endpoints
 selected were laboratory measurements of acute or chronic toxicity  at  the
 species level.  Most often the endpoint of concern for short duration
 exposures is death.  For longer duration exposures, the endpoints  of
 concern are ususally reduced growth, reproduction, and survival of
 sensitive life- stages.  Sublethal effects such as altered respiration  and
 behavior are seldom considered, although these types of impacts can have
 substantial consequences for populations as well as for communities and
 ecosystems.                                                               "

    Typically, toxicity data for a sensitive effect  (endpoint) and a
 sensitive species (receptor) are selected,  if possible, to represent the
 ecosystem as a whole, although other factors such as the type, source, and
 release pattern of the chemical, and potential pathways for fate and
 transport through the environment, are also considered.  The general
 assumption is that if a most sensitive species is protected from direct
 toxic effects of a chemical or effluent, the ecosystem will not be
 adversely affected (EPA/OWRS 1986).  It is  often necessary, however, to use
 species that can be tested reliably  in the  laboratory  (EPA/OWRS 1985) .

    The use of indicator species to  represent the ecosystem is often the
 approach taken in developing standards because it allows  expeditious review
 of a large number of chemicals, which often is required for chemical
 regulatory programs.  However, this  approach is  limited because endpoints
 are selected based on the most sensitive effects  in laboratory species;
 sensitive effects in field populations may  be different or may be altered
by density-dependent interactions in the field.   Figure 4 describes some of
 the factors that influence differences between  field and  laboratory
population responses to toxic chemicals .

    Ohio EPA, however, has developed Biological  Criteria  for  surface water
quality that are measures of fish and invertebrate  community  structure
 (Ohio EPA 1987a, 1987b, 1988).  The  criteria are  based on the values  of the
community indices measured in reference environments selected as examples
of "least impacted" surface water bodies  in each of several  ecoregions  in
 the state.  This approach avoids many of  the sources of  error associated
                                      22

-------
                                  TABLE 4

             POSSIBLE KNDPOINTS FOR ECOLOGICAL RISK ASSESSMENT
INDIVIDUALS
       Change in respiration
       Change in behavior (e.g.,  avoidance of contaminated areas)
       Inhibition or induction of enzymes
       Increased susceptibility to pathogens
       Decreased growth
       Death (particularly important in the case of endangered
        species, where the loss of even one individual is considered
        significant)

POPULATIONS
       Decreased genotypic and phenotypic diversity
       Decreased biomass
       Increased mortality rate
       Decreased fecundity
       Decreased recruitment of juveniles
       Increased frequency of disease
       Decreased yield
       Decreased growth rates

COMMUNITIES
       Decreased species diversity
       Decreased food web diversity
       Decreased productivity
       Increased algal blooms

ECOSYSTEMS
       Decreased diversity of communities
       Altered nutrient cycling
       Decreased resilience
                                      23

-------
                                              FIGURE 4


                                EXTRAPOLATION FROM LABORATORY TO FIELD -
                      DIFFERENCES BETWEEN LABORATORY STUDIES AND FIELD CONDITIONS
       Parameter
Chemical

     Characteristics


     Concentrations
Organisms
     Genetic variation

     Interaction
     Behavior
  Laboratory Bioassay
• usually exposed to one chemical

• well-defined

• can be measured

• system is well-mixed
  usually use selected genetic strain

  usually one species is exposed

  number of organisms is usually
  controlled

  organisms cannot avoid exposure
      Field Exposure
• usually exposed to a mixture

• can be measured, but olten are
  estimated

       variable, system is
        not well mixed
• high natural variability

• many species present

• density-dependent population
  fluctuations

• organisms can avoid exposure,
  emigration/immigration possible
Environment

     Toxicity modifying
     factors
  parameters closely controlled
• parameters highly variable,
 uncontrolled

-------
with extrapolating froa the laboratory into the field;  however,  it  is not
always possible to identify the source of observed degradation of the
biological communities.

    Methods Used to Set Priorities.  Ecological assessment methods  that are
used to set priorities also often use the indicator species approach
because the approach relies on readily available data (often LC5QS  or
U>50s) and provides a common base (the indicator species and endpoint) by
which all chemicals can be compared.  A few of the priority-setting methods
reviewed (EPA/OSW 1984, 1987a, EPA/OPPE 1987) explicitly characterized
receptors at a community or ecosystem level (e.g., wetlands, rivers,
forests).  However, this approach is used less frequently because  the data
base available to relate chemical stresses to changes in communities  and
ecosystems is extremely limited and situation-specific.  Therefore,
assessments of ecological impacts or potential impacts tend to be  limited
to qualitative evaluations (EPA/OSW 1987a, EPA/OPPE 1987) or are based  on
broad assumptions regarding the relationship between effects at the species
and ecosystem levels (EPA/OSW 1984)."

    Methods Used to Assess Risk for Risk Management Decisions.  Most of
the methods used for quantitative risk assessment characterize receptors
and endpoints at the species or'population level, in part because  of the
more extensive data base on toxic effects at these levels.  In an effort  tot
identify ecologically important endpoints that might otherwise be
overlooked (e.g., avoidance of spawning areas), EPA/OTS (1987) includes a
fault tree analysis in their method.

    A few of the methods used for risk assessment and risk management have
attempted to select receptors and endpoints at the community and ecosystem
level based on ecological significance.  The NAAQS review of ozone effects
(EPA/OAR 1986) and the stratospheric modification assessment  (EPA/OAR 1987)
discuss community and ecosystem-level effects qualitatively.  Some of the
more recent computer models also have attempted to model effects at the
community and ecosystem level (Barnthouse eg al.  1986, Eschenroeder 1981,
DOI 1987a).  The Barnthouse and Eschenroeder models rely in theory on
sublethal effects data, which, as mentioned previously, are often  lacking.
In these cases, the lack of experimental data on  sublethal  effects is
circumvented by assuming a generic  relationship between lethal and
sublethal effects.

2.3.2  Degree of Integration of Information Concerning Multiple Chemicals
       and Pathways

    Potential receptors can be exposed to multiple chemicals  or other
stresses via multiple pathways (e.g., water,  sediment,  food,  air).  Current
approaches to integrating multiple  pathways  and  chemicals  when  estimating
risk are related to the particular  objective  of  the  method.

    Methods Used to Set Priorities.  The  methods  used to set  priorities
(EPA/OWRS 1983, EPA/OPPE 1987) that were  based on professional  judgment did
not explicitly address multiple chemicals  or  pathways,  although these
issues presumably would be considered by  the  individuals conducting the

                                      25

-------
             analysis.  The Standard Evaluation Procedure for Ecological  Risk  (EPA/OPP
             1986) is a chemical-specific method,  but considers a different  dominant
             route of exposure for different types of receptors (aquatic  and
             terrestrial).  Similarly, because the EPA/OTS 1984 method for Estimating
             Concern Levels was developed to screen chemicals for further testing,  the
             analysis is conducted for single chemicals only.  The RCRA Risk-Cost
             Analysis model (EPA/OSW 1984) was developed to rank risks associated with
             managing multi-chemical waste streams.  The toxicity of the  waste stream in
             this method is based on the most toxic constituent of the waste stream.
   ••
'-               Methods Used to Develop Standards or Guidelines.  Multiple  pathways and
             chemicals are generally not considered in methods for standards development
             primarily because standards usually address a single chemical in a given
             medium.   In the AWQC methodology (EPA/OWRS 1986), exposure to predators
             through the food chain is addressed in addition to exposure  to  aquatic
             organisms through the water.  However, the two pathways are  not integrated
             (i.e., predatory fish are not exposed to both food and water);  the most
             protective value is chosen as the water criterion.  Similarly,  the NYS/DEC
             (1987) Fish Flesh Criteria methodology can be used to develop residue
             limits for single chemicals only.  The Water Quality-based Permitting  for
             Toxic Pollutants guidelines (EPA/OWRS 1987), however, recommend assessing
             the toxicity of whole effluents using bioassays.  The Biological Criteria
             for fish and macroinvertebrate communities developed by Ohio EPA (1988),  on
             the other hand, reflect aquatic community responses to multiple chemicals  •'•
             and other physical stresses via all routes of exposure.

                 Methods Used to Assess Risk for Risk Management Decisions.
             Consideration of multiple chemicals and pathways are particularly important
             for risk assessments conducted to support risk management decisions at
             hazardous waste sites.  At these sites, biota can be exposed to many
             different chemicals through several different environmental media.   Only
             one of the methods we reviewed, however, addresses the effects of multiple
             chemicals (EPA/OSW 1987b).   Under the hazard index approach, the ratios of
             estimated environmental concentrations to toxicity criteria are summed to
             provide  an index for total risk.  This approach assumes that toxicity is
           .  additive and, theoretically, is therefore appropriate for those chemicals
             with similar modes of action.   Although the Ecosystem Uncertainty Analysis
             (Barnthouse et al. 1986) method does not model multiple chemicals, it does
             attempt  to incorporate the effects of stresses in addition to  the toxicant.
             None of  methods reviewed examine multiple pathways, although the CERCLA
             Type A Assessment (DOI 1987a) models a different dominant route of exposure
             for different types of receptors.

             2.3.3 Treatment of Uncertainty

'                 There are many sources of uncertainty associated with ecological
             assessments.   For example,  each component of risk assessment (i.e.,
,             receptor,  toxicity,  and exposure assessment) has some uncertainty
             associated with it,  and when these components are combined  to  estimate
             risk,  new layers of uncertainty are added.  Figure  5  illustrates how
             uncertainties associated with each component of  ecological  risk


                                                   26

-------
                                              FIGURE 5


                                   UNCERTAINTY AND DATA EXTRAPOLATION
                             Increasing Uncertainty about effects
N>
 Known
Chemical
 Similar
Chemical
 Controlled  i
Environment
t  Natural
 Environment
Surrogate
  Test
Organism
                                                                                Ecosystem
                                                                               Level Effects
                                                                               Community
                                                                               Level Effects
                                                                                Population
                                                                               Level Effects
                                                                                  Other
                                                                                Organism
              Hazard
           Extrapolation
                              Exposure
                            Extrapolation
                                                    Receptor
                                                  Extrapolation

-------
 assessment can combine  to  increase the uncertainty of risk predictions.  A
 thorough  discussion of  sources and treatment of uncertainty is beyond the
 scope  of  this document.  In this section, we briefly discuss the way in
 which  the methods reviewed treat uncertainty.  The discussions are
 presented in the context of the purposes for which the various methods were
 developed.

    Methods Used to Set Priorities.  Two of the methods reviewed rely on
 professional judgment to set priorities (EPA/OPPE 1986, EPA/OWRS 1983).
 These  methods do not treat uncertainty explicitly.  The other methods for
 establishing priorities (EPA/OPP 1986, EPA/OTS 1984, EPA/OSW 1984) address
 uncertainty through the use of "application" or "assessment" factors.  The
 assessment factors are  used to derive an environmental concentration level
 which,  if equaled or exceeded, is likely to elicit an adverse ecological
 effect.   Assessment factors are based on the adequacy of available data;
 chemicals with limited  toxicity data are assigned more conservative
 application factors.  EPA/OTS (1984) has used the assessment factor
 approach  extensively and has expended, considerable effort in estimating
 appropriate factors for different sources of uncertainty.  In addition,
 EPA/OTS (1984) uses quantitative structure activity relationships (QSAR),
 when appropriate, to extrapolate from tested chemicals to untested
 chemicals.  The RCRA Risk-Cost Analysis project (EPA/OSW 1984) uses safety
 factors to account for  the quality of data used to determine the ecosystem
 threshold concentration.   A safety factor is similar to an application    •••
 factor, except that the safety factor is intended to provide an estimate  of
 the boundary between a  no  effect concentration and an effect concentration.

    Methods Used to Develop Standards or Guidelines.  A major source of
 uncertainty for methods used to develop standards or guidelines is  in  the
 definition of a reference  toxicity value.  There are many sources of
 uncertainty associated  with the use of experimentally-derived reference
 toxicity  values.  Some  of  the largest sources of uncertainty are associated
 with extrapolations of  data from a studied chemical, species, or time  frame
 to unstudied chemicals, different species or communities or ecosystems,  or
 longer time frames.  In addition, there are uncertainties associated with
 the extrapolation of responses in laboratory species to responses of
 receptors in the field.  There are also uncertainties associated with  the
 statistical methods used to derive toxicity values.

    In the methods we reviewed, the reference toxicity values used  to
 develop standards or guidelines were derived from experiments designed to
 test a hypothesis (e.g., define a no-effect level, chronic values  in
 EPA/OWRS  1986) or derived  from exposure-response data  (EPA/OAR  1986,  acute
values in EPA/OWRS 1986).  Each of these approaches has uncertainties
associated with it.  The size of the experimental error depends  in part on
the total sample size used to derive the value.  Because  the  total  sample
size needed to construct an exposure-response curve  is usually  larger than
that used in hypothesis testing, the error should be smaller  for  a toxicity
value derived from exposure-response data.   For this reason,  when they are
available, reference toxicity values derived from exposure-response data
are preferable to values derived from hypothesis  testing.
                                      28

-------
     Another common source of uncertainty is  associated with deriving
reference toxicity values for chemicals  that  have  not been  tested
extensively.  To avoid the uncertainty associated  with taxonomic variation,
EPA/OWRS (1986) does not develop AWQC unless  minimum data requirements  for
taxonomic breadth are met.  However,  as  in the  methods used to  set
priorities.,  the most common treatment of uncertainty is to  apply generic
assessment or safety factors to a toxicity value.   This approach is  used  to
extrapolate  from acute data to chronic no- or lowest-observed-effect levels
(EPA/OWRS 1986), from studied species to unstudied ones, and  from  the
effects seen in the laboratory to those  expected in the field (EPA/OTS
1984).

     In the  case of extrapolation from acute  to chronic effects, Barnthouse
e_£ al.  (1982, 1986) recommends quantifying uncertainty more rigorously,
through a statistical analysis of the extrapolation error.  For example,
under this approach, uncertainty of the  extrapolation between acute  (LC$Q)
and chronic  (MATC) toxicity data is determined by regression  of the  two
values for many species.  The error estimate  is then defined  by the
variance associated with the MATC-LC50 regression.

    Methods  Used to Assess Risk for Risk Management Decisions.   In the
methods that quantify risk, uncertainty  arises not only in conjunction with
toxicity values, but also in parameters  and models used to estimate        -.-
exposure and in the method used to integrate exposure  and toxicity
information into an estimate of risk.

    Several  techniques have been employed to address uncertainty in
exposure estimates.  DOI's (1987a) CERCLA Type A Assessment uses only  one
point (the mean) to represent the value  of each environmental parameter.
EPA/OSW (1987b) uses two values to represent a parameter:  the average  and
the plausible worst case  (e.g., upper 95th percentile).   EPA/OAR (1986)
used statistical confidence limits to bound  long-term ozone concentrations
based on confidence limits of the original (short-terra) field measurements
and the unexplained variation in the model regression used to predict  long-
term concentrations.

    For reasonably complex models, a strict  analytic accounting of  each
source of uncertainty becomes extremely  labor-intensive.   Therefore, more
complex models  (e.g. Onishi e_£ al. 1982,  1985; Barnthouse, 1982,  1986) do
not attempt to define statistical confidence limits analytically but
address uncertainty using a variety of  techniques.  These  techniques
include th« use of probability distributions as input variables (Onishi  et.
al. 1982, 1985), Monte  Carlo simulations  (e.g., randomly combining
variables chosen from several distributions; Barnthouse 1982,  1986),
sensitivity analysis, calibration, and  validation.  Although a rigorous
discussion of these techniques  is beyond the scope of this document,  these
techniques,  as used in  the methods reviewed, are  discussed briefly  below.

    The Monte Carlo simulation  technique,  used by Barnthouse e_t al. (1986),
is used to represent multiple  sources of environmental uncertainty.  A
probability distribution is measured or estimated for  each of the parameter
values.  For each  run of the Monte Carlo simulation, a  single value is

                                      29

-------
 selected  at  random for each parameter from a defined probability
 distribution.  This procedure is iterated until a reasonably stable
 probability  distribution  (convergence) is obtained for the results.  The
 variance  of  the results can then be characterized.  Monte Carlo simulation
 is a particularly useful  technique for combining multiple sources of
 variance  if  parameters are not normally distributed and if the functional
 form of the  model is non-linear.  However, Monte Carlo simulation can
 require a long time to obtain convergence, perhaps days or months.

    For important parameters that are not well-characterized (e.g.,
 indirect  effects of toxicants), sensitivity analyses can help define a
 range of  possibilities for the final predictions.  For example,
 Eschenroeder et al. (1981) analyzed the effect of variation in toxicant-
 induced mortality rates of primary producers and feeding and respiration
 rates at  various other trophic levels on the predictions of biomass
 reduction at each trophic level.  A. sensitivity analysis has also been
 performed on the surface water component of Onishi et ai.'s (1982, 1985)
 Chemical  Migration Risk Assessment methodology.

    The techniques discussed above help to define the uncertainty
 associated with a model's predictions.  Other techniques help to reduce
 model uncertainty by increasing accuracy and precision.  Validation
 consists  of assessing the accuracy of the model by comparing model inputs
 and predictions with field data.  Once model accuracy is defined,          "
 calibration of the model or submodels with field data can improve model
 accuracy.   During calibration, parameter values are varied until a close
 match is  obtained between the model predictions and the field measurements.
 The Ecosystem Uncertainty Analysis (Barnthouse et al. 1986) has been
 partially  calibrated using experimental ponds, although the model  itself
was also  modified to more closely resemble the dynamics of the ponds  (as
 described  in EPA/OTS 1987).  Several of the other models  (e.g., EPA/OAR
 1987,  Eschenroeder et al. 1981) could be calibrated using field or
historical data.   For example, the relationships between bioaccumulation  of
chemicals  and octanol/water partitioning coefficients used in Eschenroeder
et al.  (1981) could be validated using measured chemical concentrations  in
 tissues of animals at various trophic levels.
                                      30

-------
                   3.0  CONCLUSIONS AND RECOMMENDATIONS
3.1  CONCLUSIONS

    Comparison of the 20 methods  revealed that each method addresses one or
more of the components of probabilistic  risk assessment  and that  the scope
and endpoints under consideration vary considerably.   Some methods were
designed primarily to aid in the  setting of priorities (EPA/OSW 1987a,
EPA/OPPE 1987),  others to support the development of criteria and standards
(EPA/OWRS 1986,  EPA/OAR 1986,  EPA/OTS 1984),  and most of the others  to
provide input to risk management  decisions (Eschenroeder e_£ al. 1980,
Barnthouse e_t al. 1986).  Nonetheless, a few general conclusions  can be
drawn from this  review:

    •  Methods can be grouped as  qualitative or quantitative approaches;
       quantitative methods can be further grouped into  quotient  (ratio)
       methods or exposure-response (continuous) methods.

            While qualitative methods cannot be used to- develop standards
            or to quantify risk,  they can be very effective as screening o'r
            ranking tools to set  priorities.

            The  quotient method (yielding dichotomous predictions)
            appropriately addresses legislative mandates to identify "safe"
            levels of chemicals.

            Exposure-response methods (yielding continuous predictions)  may
            be more useful for risk management decisions when it  is
            important to know the degree of damage anticipated with a
            specified degree of exposure.

    •  Methods that address changes at the community or ecosystem level can
       be grouped into "top-down" approaches or "bottom-up" approaches.

            There is considerable uncertainty associated with inferring
            community- and ecosystem-level effects from laboratory
            bioassays (bottom-up  approaches).  Predictive  tools  for
            combining density-dependent  population regulation and density-
            independent processes (e.g., responses to toxic chemicals) are
            not  yet available.

            There is also uncertainty associated with addressing ecosystem-
            level effects directly (top-down approaches).   Exposure-
            response data using community- or ecosystem-level  endpoints
            (e.g., species diversity and abundance)  are extremely limited.
            Because of the limited data, these methods have generally been
            qualitative, and have been developed to  help  set  priorities,  or
            to document existing  impacts.

                                      31

-------
            Both types of approaches  are  limited  in that there is no
            accepted definition of  "ecosystem health," although
            characterization of appropriate reference environments might
            serve as an appropriate surrogate definition.

    •  As models become more complex  and  representative of real-world
       processes, other difficulties  arise.

            The more complex the model, the more  difficult it becomes to
            propagate sources of error throughout an analysis.  Other
            techniques must be applied including  validation, calibration,
            and sensitivity analyses.

            The more realistic the  model,  the less likely it is that
            adequate toxicological  data are available.  Currently,  the most
            realistic models require .estimates  for biological parameters
            for which few supportive  data exist.   In particular,  these data
            include sublethal responses to toxicants and the interactions
            between stressors (e.g.,  toxicant and temperature  tolerance).

3.2  RECOMMENDATIONS

    Based on this review, we recommend the following:

    •  Government-sponsored ecological damage assessments  and  monitoring
       efforts should be coordinated  to provide usable data  for  ecological
       exposure-response modeling and exposure  assessment.   Points for
       coordination include:

            Prescribing chemical and  physical  data collection  (e.g.,
            sampling protocol for contaminants  in different  media,
            including biological samples);

            Prescribing biological data collection (e.g.,  species
            diversity, nutrient flux, indicator species,  time  course of
            response and recovery);

            Standardizing and coordinating compilation of damage
            assessments;

            Comparison of monitoring data with predictions of ecological
            changes that might have been made prior to the initiation of
            monitoring (i.e., to verify or to refute specific modeling
            efforts based on subsequent observations);

            Use of monitoring data to rigorously define "healthy"
            ecosystems for different geographic  regions of the country;

            Sponsoring data analysis for  extraction of general ecological
            and toxicological principles.
                                      32

-------
Further laboratory- and field-based research is  needed on several
issues:

     Interactions between stressors in animal laboratory toxicity
     testing;

     Toxicant effects on sublethal endpoints such as  respiration,
     feeding rates, susceptibility to disease, and decreased
     tolerance of other stressors;

     Defining the risks associated with multiple chemical stresses
     or multichemical waste systems.  The reliability of three
     approaches to this problem could be compared:  (1) selecting  the
     single most toxic constituent to represent  the mixture,  (2)
     hazard index (EPA/OSW 1987b), and (3) bioassays  on the
     mixtures;

     Developing models that combine both density-dependent
     population interactions and density-independent  processes
     (e.g., responses to environmental contamination) in a useful
     predictive tool.

Future development of ecological risk assessment methods should    : *
address several needs:

     Increased emphasis should be placed on statistical  treatment of
     uncertainty;

     When practicable, emphasis should be placed on exposure-
     response evaluation with less emphasis on identifying  "no-
     effect-levels" based on hypothesis testing;

     Most ecological assessments deal primarily with direct  acute
     effects; increased emphasis on indirect and chronic  effects  is
     needed,  especially for non-point sources of contamination;

     There is a need to identify indicators of ecosystem health and
     to focus on ecosystem resilience and recovery in order to
     define what constitutes an acceptable level of effect and to
     focus ecosystem modeling efforts and environmental monitoring
     efforts most effectively;

     Data requirements continue to pose a problem for all but the
     most simple methods.  To improve the utility of models that
     predict community-level and ecosystem-level effects,  additional
     emphasis should be placed on the role of microcosm studies  in
     supplying input data and in calibrating model outputs.

     Endpoints should be chosen based on  ecological, societal, and
     regulatory significance, as well as  practicality.
                               33

-------
There is a need for ecosystem-level modeling efforts and more
emphasis on quantitative probability-based ecological risk
assessment methodologies.

-------
                                  GLOSSARY

The following definitions were compiled primarily  from these sources:  Rand
and Petrocelli (1985),  Krebs (1978),  Odum (1971),  Whittaker (1975),
Webster's New Collegiate Dictionary,  and the  McGraw-Hill Dictionary of Life
Sciences.

  Anadromous:   Organisms that ascend rivers  from the  sea to spawn or to
       breed.

  Assessment factor:   A factor that is  used  to  derive an environmental
       concentration level from a specified  toxicity  benchmark  (e.g.,
       LC50),  which if equaled or exceeded is likely  to cause an adverse
       ecological effect.

  Benthos:   Organisms that live on or'in the  bottom of bodies of water.

  Bioaccumulation:   The net uptake of chemicals by organisms directly from
       water or through consumption of  food  containing the chemicals.

  Bioconcentration:   The net uptake of  chemicals by aquatic organisms from. .
       water.

  Biomagnification:   The net increase in chemicals in organisms at
       successively higher trophic levels as  a  consequence of ingesting
       contaminated organisms at lower  trophic  levels.

  Calibration:   The adjustment of model parameter  values using  field data.

  Community:   An assemblage of populations of plants, animals,  bacteria,
       and  fungi that live in an environment and interact with  one  another,
       forming a distinctive living system with its own composition,
       structure,  environmental relations, development, and  function.

  Copepod:   Any of a large class of microscopic freshwater and  marine
       crustacea;  also,  one of the most abundant types of animal  in marine
       zooplankton.

  Demersal:   Living at  or near the bottom of the sea.

  Density dependence:   A density-dependent effect  alters  the  birth rate  or
       the  death rate of a population as a function of  the density of  the
       population.   Examples of factors that can have density-dependent
       effects  include  competition among members of the population, rates
       of attack by parasites and predators,  and emigration.

  Deterministic:   A unique output or result  produced  by a specified input
       (stochastic  or random selection of parameters  from probability
       distributions  are not incorporated).
                                      35

-------
Diel: A 24-hour period, usually including the day and following night.

EC50: Median effective concentration.   The concentration of  material  in
     water that is estimated to be effective in producing some sublethal
     response in 50% of test organisms.   Often used in reference  to
     immobilization of invertebrates or reduced growth of algae.

Ecological damage assessment:   A subcategory of ecological impact
     assessment that measures effects that have already occurred  in  an
     ecosystem or any part of an ecosystem as the result of  a
     perturbation.  As the phrase is used in this report, damage
     assessments can measure injury (i.e., adverse effects that may  not
     have economic consequences) as well as damage (i.e., adverse effects
     that can be measured in economic terms).  Measurements  of  damages
     that have already occurred can be used as input into probabilistic
     ecological risk assessments.

Ecological impact assessment:   A subcategory of environmental impact
     assessment that addresses impacts on non-human biota by documenting
     and/or estimating the occurrence of impacts within an ecosystem or
     any part of an ecosystem, and the consequences of the occurrence.

Ecological risk assessment:  A subcategory of ecological impact         -.--
     assessment that (a) predicts the probability of adverse effects
     occurring in an ecosystem or any part of any ecosystem as'a  result
     of a perturbation and (b) relates the magnitude of the impact to the
     perturbation.

Ecological risk management analysis:  A decision-making process that
     considers political, social, economic, and engineering information
     in conjunction with risk-related information to select an
     appropriate regulatory response to a potential ecological problem.

EEC:  Estimated environmental concentration.

Environmental impact assessment:  A broad field that includes all
     activities that attempt to analyze and evaluate the effects of human
     action on natural and anthropogenic environments  (after Suter e_t al.
     1987).

Ecosystem:  The biotic community and its environment which, together,
     function as a system of complementary relationships, with the
     transfer and circulation of energy and matter.

Environmental impact assessment: A broad  field  that  includes all
     activities that attempt to analyze and evaluate  the effects  of  human
     action on natural and anthropogenic environments  (after Suter  et al.
     1987).

Environmental Impact Statement  (EIS):  An  assessment of the impacts  of  a
     specific Federal action as required  by  the  National Environmental
     Policy Act (NEPA).  Although an EIS  may  use  ecological risk

                                    36

-------
      assessment  as  a  tool for comparing alternatives, an EIS is required
      only to  provide  a  "full and fair discussion of significant
      environmental  impacts".

 Environmental risk  assessment:  A procedure that predicts (a) the
      possibility of adverse effects occurring to human health or the
      environment and  (b) the consequences of the adverse effects (after
      NRG  1975).

 Fecundity:  Potential capability of an organism to produce viable
      offspring.

 GMATC:  The point estimate of the Maximum Acceptable Toxicant
      Concentration  (MATC) calculated as the geometric mean of the no-
      effect level (NOEL) and the low-effect level (LOEL) taken from life-
      cycle or partial life-cycle toxicity tests.

 Hardness:  The concentration of all'divalent metallic cations, except
      those of the alkali metal, present in water.  In general, hardness
      is a measure of  the concentration of calcium and magnesium ions in
      water and is frequently expressed as mg/1 calcium carbonate
      equivalent.

 Hazard assessment:  A  component of risk assessment that consists of the
      review and  evaluation of toxicological data to  identify  the nature
      of the hazards associated with a chemical, and  to quantify the
      relationship between dose and response.

 Ichthyoplankton:  The drifting eggs and larvae of many species of fish.

 LC50:  Median lethal  concentration.  The concentration of substance  in
      water that  is  associated with the death of 50%  of the organisms in  a
      laboratory  bioassay.  This notation is also used to describe other
      proportions; for instance LC^gt ^25, and LC^ refer to  the
      concentrations estimated to kill 10%, 25% and 1% of the  test
      organisms,  respectively.

 LOEL:  Lowest observed  effect level.  The lowest level or concentration
      of a material  used in a toxicity test that produces a  statistically
      significant adverse effect on the exposed population of test
      organisms as compared with the controls.

 MATC:  The toxic chemical threshold concentration lying  in  a range
      bounded  at  the lower end by the highest tested  concentration having
      no effect (NOEL) and at the higher end by the lowest tested
      concentration  having a significant toxic effect (LOEL)  in a life
      cycle (full chronic) or partial life cycle  (partial chronic)  test.

Microcosm:  A laboratory simulation of a portion of  an  ecosystem (e.g.,  a
      terrarium).
                                    37

-------
 Mesocosm:  A composite physical and biological model of an ecosystem,
      intermediate  in scale between a microcosm and a macrocosm,  with a
      level of organization as high as the natural world (e.g.,  ponds).

 Macrocosm:  A composite physical and biological model of an ecosystem,
      large in scale, with a level of organization as high as the natural
      world (e.g.,  an experimental watershed including terrestrial and
      aquatic ecosystems).

 Macroinvertebrates:  Invertebrate species that are sufficiently large to
      be handled without the aid of a microscope.

 Monte Carlo simulation:  An iterative modeling technique where parameter
      values are drawn at random from defined probability distributions,  a
      solution defined, and the process repeated until a stable
      distribution  of solutions results.

 NOEL:  No observed effect level.  The highest concentration in a toxicity
      test that has no statistically significant adverse effect on the
      exposed population of test organisms as compared with the controls.

 Niche:  Role or "profession" of an organism in the environment; its ac-
      tivities and  relationships in the community.                        •• •.

 Piscivorous:   Fish-eating.

 Phytoplankton:  Drifting aquatic plants, usually uni-cellular.

 Phytotoxic:  Toxic to plants.

 Planktivorous:  Eats drifting aquatic organisms.

 Plankton:  Microscopic or small macroscopic plants and animals which live
      freely in surface water and which, because of their limited powers
      of locomotion, drift with the water currents.

 Population:  A potentially interbreeding group of individuals of a  single
      species.

 Primary productivity:  The rate at which radiant energy  is  stored by
      photosynthetic and chemosynthetic activity of producer organisms
      (chiefly green plants) in the form of organic substances.

QSAR:  Quantitative structure activity relationship: a method  of
      estimating unmeasured physical and toxicological properties  for  a
      chemical on the basis of chemical structure, functional groups,  and
      similarity to known chemicals.

Receptor:  The entity (e.g., organism, population, community,  ecosystem)
      that might be adversely affected by contact with  or exposure to a
      substance of  concern.
                                    38

-------
Resilience:  The ability of a system to recover from perturbations.

Resistance:  The ability of a system to absorb an impact without
     significant change from normal fluctuations.

Risk management:  The process of weighing policy alternatives and
     selecting the most appropriate regulatory action based on the
     results of risk assessment.

Secondary productivity:  Rate of energy storage by heterotrophic
     organisms (i.e., rate of energy storage at consumer levels -
     herbivores, carnivores, or detritus feeders).

Species:  A group of closely related, morphologically similar individuals
     which actually or potentially interbreed.

Stochastic:  A process involving a random variable.

Stratosphere:  The upper portion of the atmosphere, in which temperature
     varies very little with changing altitude and clouds are rare.

Trophic level:  Functional classification of organisms in a community
     according to feeding relationships; the first trophic level includes,
     green plants; the second trophic level includes herbivores; and so
     on.

Validation: The testing of a model against reality.

Zooplankton:  Drifting aquatic animals.
                                    39

-------
                                REFERENCES
 Ballou.  S.W., J.B.  Levenson, K.E. Robek, and M.H. Gabriel.  1981.   Regional
      Ecological Assessments:  Concepts, Procedures and Application.   Argonne
      National Laboratory, Energy and Environmental Systems Division,
      Argonne, Illinois.

 Barnthouse, L.W., D.L. DeAngelis, R.H. Gardner, R.V. O'Neil, C.D.  Powers,
      G.W. Suter, and D.S. Vaughn.  1982.  Methodology for Environmental Risk
      Analysis.  Environmental Sciences Division Publication No. 2023. Oak
      Ridge National Laboratory, Oak Ridge, Tennessee.

 Barnthouse, L.W., G.W. Suter, S.M. Bartell, J.J. Beauchamp, R.H.  Gardner,  E.
      Linder, R.V. O'Neill, and A.E. Rosen.  1986.  User's Manual for
      Ecological Risk Assessment.  Environmental Sciences Division
      Publication No. 2679.  Oak Ridge National Laboratory, Oak Ridge,
      Tennessee.

 Department of the Interior (DOI). 1987a.  Measuring Damages to Coastal and
      Marine Natural Resources.  Concepts and Data Relevant for CERCLA Type A
      Damage Assessments, Volumes I and II.  CERCLA 301 Project, Washington,
      D.C.

 Department of the Interior (DOI). 1987b.  Natural Resource Damage
      Assessments.   Final Rule (for Type B Assessments).  Federal Register.
      51: 27674-27753.  Friday, August 1, 1987.

 Environmental Protection Agency/Office of Policy Planning and Evaluation
      (EPA/OPPE).  1987.  Unfinished Business:  A Comparative Assessment of
      Environmental  Problems.  Appendix III.  Ecological Risk Work Group,
      Office of Policy, Planning and Evaluation.  Washington, D.C.

 Environmental Protection Agency/Office of Air and Radiation (EPA/OAR).
      1986.  Review  of the National Ambient Air Quality Standards for Ozone.
      Preliminary Assessment of Scientific and Technical Information.  Staff
      Paper.

 Environmental Protection Agency/Office of Air and Radiation (EPA/OAR).  1987.
     An Assessment  of the Risk of Stratospheric Modification, Volumes I-V.
     Washington, D.C.

 Environmental Protection Agency/Office of Pesticide  Programs  (EPA/OPP).
      1986.  Standard Evaluation Procedure for Ecological Risk Assessment,  by
     D.J. Urban and N.J. Cook, Hazard Evaluation Division.  Washington, D.C.

Environmental Protection Agency/Office of Solid Waste  (EPA/OSW).   1984.   The
     RCRA Risk-Cost Analysis Model.  Phase III Report.  Submitted  to the
     Office of Solid Waste Economic Analysis Branch.   Environmental
     Protection Agency, Washington, D.C.  March  1,  1984

                                    40

-------
Environmental Protection Agency/Office of Solid Waste  (EPA/OSW).   1987a.
     Potential for environmental damage:   proximity of mine waste  sites to
     sensitive environments.  Chapter 6 in Risk Screening Analysis  of Mining
     Wastes.  Draft Report.   Environmental Protection  Agency,  Washington,
     D.C.

Environmental Protection Agency/Office of Solid Waste  (EPA/OSW).   1987b.
     Technical Resource Document for Variances from the Secondary
     Containment Requirement of Hazardous Waste Tank Systems.  Volume  II:
     Risk-based Variance.  Environmental Protection Agency, Washington, D.C.

Environmental Protection Agency/Office of Toxic Substances (EPA/OTS).   1984.
     Estimating "Concern Levels" for Concentrations of Chemical  Substances
     in the Environment.  Environmental Effects Branch, Health and
     Environmental Review Division.   Washington, D.C.   February  1984.

Environmental Protection Agency/Office of Toxic Substances (EPA/OTS).   1987.
     Ecological Risk Assessment in The Office of Toxic Substances.  Problems
     and Progress.  1984-1987.   by D.J. Rodier, Environmental Effects
     Branch.  September 4, 1987.

Environmental Protection Agency/Office of Water Regulations and Standards1'
     (EPA/OWRS).  1983.  An Approach to Assessing Exposure to and Risk of
     Environmental Pollutants.

Environmental Protection Agency/Office of Water Regulations and Standards.
     (EPA/OWRS).  1985.  Technical Support Document for Water Quality-Bsed
     Toxics Control.  Washington, D.C.  EPA-440/4-85-032.

Environmental Protection Agency/Office of Water Regulations and Standards.
     (EPA/OWRS).  1986.  Guidelines for Deriving Numerical Water Quality
     Criteria for the Protection of Aquatic Organisms  and their Uses.
     Washington, D.C.

Environmental Protection Agency/Office of Water Regulations and Standards.
     (EPA/OWRS).  1987.  Permit Writer's Guide  to Water Quality-Based
     Permitting for Toxic Pollutants.  Washington,  D.C.   EPA 440/4-87-005.

Eschenroeder, A., E. Irvine, A. Lloyd, C. Tashima,  and K. Tran.   1980.
     Computer simulation models for assessment  of  toxic  substances.   Pp.
     323-368, in R. Haque, ed.   Dynamics, Exposure  and Hazard Assessment of
     Toxic Chemicals.  Ann Arbor Science  Publishers Inc., Ann Arbor,
     Michigan.

Kickert, R.N., and Miller, P.R.  1979.   Responses  of  ecological  systems.
     In:  Handbook of Methodology for  the Assessment  of Air  Pollution
     Effects on Vegetation.  Air Pollution  Control Association,  Pittsburgh,
     PA.

Krebs,  C.J.  1978.  Ecology:   the Experimental Analysis of Distribution and
     Abundance.  Harper  and Row  Publishers,  New York, New York.

                                    41

-------
 Levin,  S.A.,  K.D.  Kimball,  W.H. McDowell, andS.F. Kimball (eds.).   1983.
      New Perspectives  in  Ecotoxicology.  Ecosystem Research Center,  Cornell
      University,  Ithaca,  New York.

 McGraw  Hill.  1974.   Dictionary of  the Life Sciences.  McGraw Hill, Inc.,  New
      York,  New York.

 National Research  Council (NRC).   1981.  Testing for Effects of Chemicals on
      Ecosystems.   National Academy Press, Washington, D.C.

 New York State Department of Environmental Conservation (NYS/DEC).  1987.
      Niagara  River biota  Contamination Project:  Fish Flesh Criteria for
      Piscivorous Wildlife.  Division of Fish and Wildlife, Bureau of
      Environmental Protection.  DEC Publication.  Technical Report 87-3.

 Nuclear Regulatory Commission (NRC).  1975.  Reactor Safety Study:  Main
      Report.  WASH-1400 (NUREG 75/014), October.

 Odum, E.P.  1971.  Fundamentals of Ecology.  W.B. Saunders Company,
      Philadelphia, Pennsylvania.

 Ohio  EPA.   1988.   Biological Criteria for the Protection of Aquatic Life:.
      Volume I.  The  Role  of Biological Data in Water Quality Assessment.-.'
      February 15,  1988.   Ohio Environmental Protection Agency, Division  of
      Water Quality Monitoring and  Assessment, Surface Water Section.
      Columbus, OH.   Doc.  0055e/0015e.

 Ohio  EPA.   1987a.  Biological Criteria for the Protection of Aquatic Life:
      Volume II.  Users Manual for  Biological Field Assessment of  Ohio
      Surface  Waters.  October 309, 1987.   Ohio Environmental Protection
      Agency,  Division of  Water Quality Monitoring and Assessment, Surface
      Water Section.  Columbus, OH.  Doc. 0046e/0013e.

 Ohio  EPA.  1987b.  Biological Criteria for the Protection of Aquatic Life:
      Volume III.   Standardized Biological Field Sampling and laboratory
      Methods  for Assessing Fish and Macroinvertebrate Communities.   October
      30,  1987.  Ohio Environmental Protection Agency, Division of Water
      Quality  Monitoring and Assessment, Surface Water Section.  Columbus,
      OH.  Doc. 0046e/0013e.

 Onishi,  Y., A.R. Olsen, M.A. Parkhurst, and G. Whelan.   1985.  Computer
     based environmental  exposure  and risk assessment methodology for
     hazardous materials.  J.  Haz. Mat.  10: 389-417.

Onishi,  Y., S.M. Brown, A.R. Olsen, M.A. Parkhurst,  S.E. Wise, and  W.H.
     Waters.  1982.  Methodology for Overland and  Instream Migration and
     Risk Assessment of Pesticides.  EPA-600/3-82-024.

Rand,  G.M. and  S.R. Petrocelli.   1985.  Fundamentals of Aquatic  Toxicology.
     Methods  and Applications.  Hemisphere Publishing Company, Washington,
     D.C.

                                    42

-------
Sucer, G.W.. Barnthouse, L.W. ,  and O'Neill, R.V.  1987.   Treatment of Risk
     in Environmental Impact Assessment.  Environmental  Management Vol.  11:
     295-303.

Webster's New Collegiate Dictionary.  1977.  G. & C. Merriam Company,
     Springfield, Massachusetts.

Whittaker, R.H.  1975  Communities and Ecosystems.  2nd ed.  MacMillan
     Publishing Co., Inc., New York, NY.
                                    43

-------
               APPENDIX A
FRAMEWORK FOR REVIEW OF LEGAL MANDATES
AND ECOLOGICAL ASSESSMENT METHODOLOGIES

-------
                                  APPENDIX A

                              TABLE OF CONTENTS

                                                                 Page

 INTRODUCTION	  A- 1

 1.0  Framework for Reviewing Legal Mandates	  A-2

 2.0  Framework for Reviewing Technical Aspects of
     Ecological Assessment Methodologies	  A-2

     2.1  Receptor Characterization	  A-2
     2.2  Hazard Assessment	  A-2
     2.3  Exposure Assessment 	  A-6
     2.4  Risk Characterization	  A-6

 3.0  Framework for Reviewing Operational
     Resource Requirements	  A-9
                                LIST OF TABLES


A-l  Framework for Reviewing Legal Mandates  	 A-3

A-2  Framework for Reviewing Receptor Characterization  	 A-4

A-3  Framework for Reviewing Hazard Assessment  	 A-5

A-4  Framework for Reviewing Exposure Assessment  	 A-7

A-5  Framework for Reviewing Risk Characterization  	 A-8

A-6  Framework for Reviewing Operational Resource Requirements  . A-10

-------
Review Framework                                                   Page A-3




                                  TABLE A-l

                    FRAMEWORK FOR REVIEWING LEGAL MANDATES
1.0  Legislative Mandate
     1.1  Requires ecological risk assessment
     1.2  Requires consideration of ecological impacts
     1.3  May require consideration of ecological impacts
     1.4  Not relevant to ecological impacts

2.0  Executive Order Directive
     2.1  Requires ecological risk assessment
     2.2  Requires consideration of ecological impacts
     2.3  May require consideration of ecological impacts
     2.4  Not relevant to ecological impacts

-------
Review Framework                                                    Page A-4


                                  TABLE A-2

              FRAMEHORK FOR. REVIEWING RECEPTOR CHARACTERIZATION
1.   Type
     1.1  Aquatic
     1.2  Terrestrial

2.   Level
     2.1  Individual (e.g., endangered species)
     2.2  Population (e.g., game species, keystone species)
     2.3  Biotic community (e.g., one .guild, food web)
     2.4  Ecosystem

3.   Receptor Specificity
     3.1  Generic (e.g., generic indicator species)
     3.2  Site-specific (e.g., Chesapeake Bay)

4.   Temporal Characterization
     4.1  Seasonal (e.g.,  breeding, migration)
     4.2  Life cycle

5.   Niche (life habit) Characterization

-------
Review Framework                                                    Page  A-5


                                  TABLE A-3

                  FRAMEWORK FOR REVIEWING HAZARD ASSESSMENT
1. Individual/Population Receptors
   1.1  Acute criteria (i.e., short duration exposure; e.g.,  LC5Q)
   1.2  Chronic criteria (i.e., longer term exposure; e.g.,  stunted growth)
   1.3  Mechanism of action
   1.4  Exposure-response

2. Community/Ecosystem Endpoints
   2.1  Criteria
   2.2  Exposure-response

3. Toxicity Modifying Factors
   3.1  Abiotic conditions/stresses
   3.2  Biotic stresses (e.g., competition)
   3.3  Behavioral changes
   3.4  Bioconcentration                                                  :

4. Treatment of Uncertainty
   4.1  Generic safety factors
   4.2  Ranges
   4.3  Statistical extrapolation

5.  Hazard Value Derivation
   5.1  Apply relative weights to effects
   5.2  Choose most sensitive effect

-------
Review Framework                                                    Page  A-6


populations, communities) and may consider a variety of receptor-specific
toxicity values (e.g., acute, chronic, dose - response),  as well as the  general
factors which influence the probability (e.g., toxicity modifying factors) or
interpretation (e.g., hazard value derivation, treatment of uncertainty)  of  a
toxic response.  Ecological assessment methodologies may be characterized and
differentiated to a large degree based on variations in the approaches for
hazard assessment.

   Complete evaluation of potential toxicological hazards should include
evaluation of lethal and sublethal endpoints at the individual, population,
community, and ecosystem receptors.  Historically, most toxicological data
used in environmental assessments have been measurements of laboratory
population responses, such as LC5Q and MATC values.  The majority of current
approaches continue with this emphasis.  Community-level toxicity tests (e.g.,
effects on community diversity) have 'not been standardized enough to be widely
used in current methods.

   With regard to toxicity values, acute and chronic criteria, mechanisms of
action, and dose-response information have been used or may be used in
ecological hazard assessments and are considered to represent currently   -.-.
feasible approaches.  Similarly, some assessment methodologies consider
toxicity modifying factors (e.g., abiotic and biotic stresses) and incorporate
estimates of uncertainty.

2.3  EXPOSURE ASSESSMENT

   An exposure assessment estimates the chemical-specific concentrations to
which receptors are exposed.  As shown in Table A-4, exposure assessments can
encompass multiple exposure pathways, concentration variations,  toxicity
modifying factors, and uncertainties surrounding  the exposure estimates.

2.4   RISK CHARACTERIZATIOH

   The final stage in the ecological assessment process  is  the  integration of
the information derived during receptor characterization, hazard assessment,
and exposure assessment to generate an estimate of  impact or  risk.  Risk
characterization varies with respect to the type  of approach/model  used  to
estimate risk (e.g., qualitative, quantitative);  the degree of integration  of
multiple stressors or pathways of exposure, and the applicability of  the
approach/model to a variety of situations.  In addition,  models used  for risk
characterization vary in the treatment of uncertainty  and in  the degree  to
which they are validated, calibrated, verifiable,  and  sensitive. Each of
these characteristics is listed  in Table A-5.

-------
Review Framework                                                   Page A-7



                                  TABLE A-4

                 FRAMEWORK FOR REVIEWING EXPOSURE ASSESSMENT
1. Exposure Pathways
   1.1  Soil
   1.2  Air
   1.3  Water
   1.4  Sediment
   1.5  Food

2. Concentration Estimation Methods
   2.1  Spatial variation within/between media (e.g.,  concentration is a
        continuous or step function of distance from source)
   2.2  Temporal variation within/between media (e.g., steady state or time
        varying contaminant release)
   2.3  Toxicokinetics (e.g.,  bioconcentration of substance)
                                                                          : '•
3. Characterization of Toxicity Modifying Factors (e.g., D.O., pH,
   temperature)

4. Treatment of Uncertainty
   4.1  Deterministic model
   4.2  Average (i.e., typical case) or maximum (i.e., worst case) estimates
   4.3  Probability distribution of concentrations

-------
 Review Framework                                                    Page A-8


                                  TABLE A-5

                FRAMEWORK  FOR REVIEWING RISK CHARACTERIZATION


 1.  Type of Approach
    1.1 Qualitative
    1.2 Quantitative

 2.  Degree of  Integration
    2.1 Contaminants
        2.1.1  Single  (or  indicator) chemical
        2.1.2  Multiple chemicals

    2.2 Route of Exposure
        2.2.1  Single  route or dominant route
        2.2.2  Multiple routes

    2.3  Contributions  of Other Stresses

 3.  Applicability of Model/Approach
    3.1  Limited (e.g., specific to a particular situation or locality)
    3.2  Broadly applicable/flexible

4.  Treatment of Uncertainty
    4.1  Reflects uncertainty in measurements
    4.2  Reflects biotic and environmental variability
    4.3  Estimates probability distribution of effects

5.  Can Be Validated
    5.1  Has been partially field tested
    5.2  Has been completely field tested
    5.3  Can be field tested

6.  Can Be Calibrated (i.e., adjusted to reflect the environmental situation at
   hand)

7. Can be Evaluated for Sensitivity (i.e., changes in output of model
   accurately reflect changes of inputs)

8.   Is Verifiable
   8.1  Model code/behavior accurately represents algorithm
   8.2  Algorithms are scientifically reasonable and/or field verified

-------
Review Framework                                                    Page A.-9
        3.0  FRAMEWORK FOR REVIEWING  OPERATIONAL RESOURCE REQUIREMENTS

   Our review of operational resource concerns addresses the issue that while
some aspects of methodologies do not affect the scientific approaches of the
model, they may influence the degree to which the model  is applied.  For
example, a complex computer simulation model may be extremely expensive to
run, and this may limit its use.  In addition, complex models may require data
that are not available for a wide range of chemicals or  organisms.  The
primary operational resource concerns considered are data availability, cost,
and the level of effort and skill required to implement  the ecological
assessment.  The framework for reviewing operational resource requirements is
given in Table A-6.

-------
Review Framework                                                    Page A-LO


                                  TABLE A-6

          FRAMEWORK FOR REVIEWING OPERATIONAL RESOURCE REQUIREMENTS
1.  Data Availability
   1.1  Available (i.e., most receptors,  most chemicals)
   1.2  Limited availability (i.e.,  few receptors,  few chemicals)
   1.3  Can be extrapolated using similar species/populations or chemicals

2.  Cost/Level of Effort
   2.1  High
   2.2  Medium
   2.3  Low

3.   Level of Skill Required
   3.1  High
   3.2  Low

-------
                         APPENDIX B




REVIEW OF LEGAL MANDATES FOR ECOLOGICAL RISK ASSESSMENTS

-------
                              TABLE OF CONTENTS

                                                                 Page
INTRODUCTION AND MAJOR CONCLUSIONS		  B-1

1.0  Statutes and Directives Administered by EPA

     1.1  Comprehensive Environmental Response,
          Compensation, and Liability Act (CERCLA)	  B-3
     1.2  Clean Air Act	  B-12
     1. 3  Clean Water Act	  B-12
     1.4  Federal Insecticide,  Fungicide,  and
          Rodenticide Act (FIFRA)	  B-13
     1.5  Marine Protection and Research
          Sanctuaries Act (MPRSA)		  B-14
     1.6  Resource Conservation and Recovery
          Act (RCRA)	  B-14
     1.7  Safe Drinking Water Act  (SBWA)	  B-15
     1.8  Toxic Substances Control Act (TSCA)  	  B-15

2.0  Statutes and Directives Administered by Other Federal Agencies,

     2.1  Coastal Zone Management  Act of 1972  	  B-17
     2.2  Endangered Species Act 	  B-17
     2.3  Executive Order 11988, Floodplain Management 	  B-17
     2.4  Executive Order 11990, Protection of Wetlands 	  B-17
     2.5  Fish and Wildlife Coordination Act	-.	  B-20
     2.6  National Environmental Policy Act (NEPA) 	  B-20
     2.7  Wild and Scenic Rivers Act 	  B-20
                                      B-i

-------
 Legal Mandates  for Ecological Risk Assessment                      Page  B-l

                      INTRODUCTION AND MAJOR CONCLUSIONS

     This appendix presents a review of legal mandates for ecological  risk
 assessment.  The review includes  15 statutes and directives,  eight of  which
 are administered by EPA, with the remaining seven administered by other
 agencies within the Federal government.  We also examined the legislative
 histories for several statutes in order to interpret the intent of specific
 provisions within the legislation.  It should be noted that a review of
 regulations promulgated in the Federal Register was outside the scope  of this
 project.  Hence, specific regulations for ecological risk assessment such  as
 those promulgated under FIFRA (e.g., 40 CFR 162.11) are not addressed in this
 document.  The  statutes and directives administered by EPA are presented
 first, followed by the legislation administered by other Federal agencies.

     Protecting the environment or various components of the environment is  a
 clear common goal or objective of each of the 15 statutes and directives
 reviewed.  The  statutes and mandates*do not describe specifically how
 protection of the environment is  to be accomplished.  Nevertheless, given the
 goals and objectives of the statutes and directives, it is arguable that all
 may require some consideration of ecological impacts even though none
 explicitly requires formal ecological risk assessment.  However, all of them
 allow, and some appear to actually encourage, conducting an ecological risk'
 assessment.

     Of the eight statutes administered by EPA, four appear to require
 consideration of ecological impacts in support of standards, limitations,  and
 regulations development.  Ecological  impact considerations are also required
 to support waivers, exemptions, etc., from regulatory standards, limitations,
 and requirements, and to support  research activities related to  the impacts of
 regulations or  in support of future regulations.  These statutes specify the
 activities or biota for which a consideration of environmental impact is
 required (e.g., propagation of shellfish, fish, etc.).  The remainder of the
 statutes administered by EPA may  require consideration of ecological  impact
 and would allow the use of administrative discretion to require  an assessment
 to ensure protection of the environment.  In general, these statutes  and
 directives do not specify activities  and biota for which an assessment must be
 provided or which methods must be used in performing the assessment.

     The Clean  Air Act (CAA), Clean Water Act  (CWA), the Federal Insecticide,
 Fungicide, and  Rodenticide Act (FIFRA), the Marine  Protection, Research, and
 Sanctuaries Act (MPRSA), the Endangered Species Act  (ESA),  the National
 Environmental Policy Act (NEPA),  the  Wild and  Scenic Rivers Act,  and  Executive
 Order 11990 (Protection of Wetlands)  require consideration  of  ecological
 impacts.   Of these statutes, the  CAA, CWA,  FIFRA,  and MPRSA are  administered
 by EPA.   Each of these statutes contains sections  for which consideration of
 ecological impacts is required and sections which  seem  to  encourage performing
 formal ecological risk assessments.   For example,  to obtain a  modification  of
 secondary treatment requirements  under Section 301(h) of  the  CWA,  a
municipality must first demonstrate that the modification will not result  in
 interference with maintenance of  water quality that ensures the  "protection
 and propagation of a balanced, indigenous population  of shellfish,  fish,  and
wildlife."  Under Section L02(a)  of MPRSA,  prior  to issuing a  permit  for  ocean

-------
Legal Mandates for Ecological Risk Assessment                      Page B-2

dumping, the Administrator must consider the effects on marine ecosystems,
including the transfer, concentration, and dispersion of waste, the potential
changes in marine ecosystem diversity, productivity, and stability, and marine
species and community population dynamics.

     The Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA),  the Resource Conservation and Recovery Act (RCRA), the Toxic
Substances Control Act.(TSCA), the Safe Drinking Water Act  (SDWA),  the Coastal
Zone Management Act of 1972 (CZMA),  the Fish and Wildlife Coordination Act,
and Executive Order 11988 (Floodplain Management) may require consideration of
ecological impacts.  Of these, CERCLA, RCRA, SDWA, and TSCA are administered
by EPA.  Sections within each of these statutes require that environmental
impacts be considered.  Implicitly,  this includes ecological impacts.  In
addition,  each statute provides sufficient administrative discretion and
flexibility to require this consideration.   For example, authorization for
the land disposal of hazardous wastes under RCRA Sections 3004(d)  and  (e) can
be granted only for disposal methods that are shown to be protective of human
health and the environment.

-------
 Legal Mandates  for  Ecological Risk Assessment                      Page  B-3

               1.0  STATUTES AND DIRECTIVES  ADMINISTERED BY EPA

      Table  B-l  provides a summary of ecological assessment requirements  of
 eight statutes  and  directives administered by EPA.  A brief description  of  the
 requirements  for each statute and directive is provided belov.

 1.1   Comprehensive  Environmental Response. Compensation,  and Liability
      Act  (CERCLA)

      The  objective  of CERCLA (including amendments made under the Superfund
 Amendments  and  Reauthorization Act of 1986) is to establish a National program
 for  responding  to releases of hazardous substances into the environment.
 CERCLA establishes  the process for determining appropriate remedial actions at
 Superfund sites; remedial actions selected are required to be cost-effective
 and  adequate  to protect public health.

      Several  sections of CERCLA require that environmental impact assessments
 be performed  for certain activities, although neither the Act nor its
 legislative history specifies methods or techniques for the assessments.  The
 environment is  defined to include natural resources that are under the
 exclusive management authority of the U.S.  Natural resources are further
 defined under CERCLA to include land, fish, wildlife biota, air, water,  ground
 water,  drinking water supplies, and other resources.  Therefore, although
 there  is  not  an explicit requirement for an ecological assessment, the
 definitions provided could be interpreted to require one.

     Under  the National Contingency Plan, Section 105 of CERCLA, several
 provisions  require  the consideration of the threat of, and subsequent hazards
 related to, the release of hazardous substances to the environment.  Section
 105(a)(8)(A)  requires criteria to be established for determining priorities
 among  releases or threatened releases of hazardous substances for purposes of
 taking  removal actions.  These criteria must be based upon "the relative risk
 or danger to... the environment, (including) the potential for destruction of
 sensitive ecosystems."  Under Section 105(d) of CERCLA, the President can be
 petitioned  to conduct a preliminary assessment of a release or threatened
 release of a hazardous substance.  This preliminary assessment must consider
 the hazards associated with a release or threatened release posed to public
 health  and  the environment.  To add facilities to the National Priorities List
 (NPL) pursuant to Section 105(g) of CERCLA, the potential exposure and  hazard
 of substances to human health and the environment must be considered.   Section
 121  (added pursuant to the 1986 amendments) of CERCLA defines how to assess
 alternative remedial actions and the degree of cleanup required  for Superfund
 sites.  This assessment must account in part for  the potential  threat to human
 health  and the environment.  Section 301(c) of CERCLA specifies  that  two types
 of procedures be developed to assess damages "for injury  to, destruction of.
 or loss of natural resources resulting from a release of  oil or  a hazardous
 substance."  The first type of procedure must include minimal  field
 observation.  The second type must include  protocols  for  assessing damage  on a
 case-by-case basis, including identification of the best  available procedures
 to determine such damages considering factors such  as replacement  value,  use
value, and ability of ecosystem or resource to recover.

-------
Legal Mandates for Ecological Risk Assessment
Page B-4














0.
•1
t

H
M
td
01
01
1
3

i

I

1
Z
Lf
j


*

O
g
•4
§
=)
01







































Citation Summary








•

a

"

.. v

••< c
U
e e
u u
u •
jj ^^
u ^>
£ *4
S —
3
S 2
m. Si
m
.2

••«*
jhj


u
*






•"• •)
.0 %•»
38
••4 ••»
a u

e
o
4J
JI
£)
•44


J
«

•- • e
4. • .-
•« 4) 'C ,
.2"°.- S

"b c" C 2
a <• — •
a a- 5
o e a
— « « u
v •> i «
> e e
•8 | 25

44 b C •-
red in part to develop criteria
he national hazardous substance
relative risk or dancer to the e
otential for destruction of sens
3 e
a b o w
«> o a £











e
a

u
c
e
e
o


o

a
X

£



e
§
•«•!
.•
•)
4|
"
3
ee

*
JC
C

M
e
< 3
•? "" *"

at e ac
lu •- <
U ~ V.

£
U


b
* £
N 44
9 '•*
£ J
« "0
£ «
° o"
•fl •
" •
minary assessment must be conduc
blic health and the environment
sc or threatened release.
- ss

a? 2 S







4. J
e •
IJ!
V
b
e
V
44
e b
• «4 £
1 44
^" b
« e
w
a v
m m

o •
•8 u
e « .
8*

0 •
44 e
b

f*
e e
e ••»
— w ^
— "a «
44 •
V M ^4
a. b o


^
"^
^
c










14.
Q
O

0
••4 41 44
" b C

o — e
u <• v
"0 'C W
c e £
« 41 44
to consider quantity, toxicity,
dous substances, exposure or pot
onment, and degree of hazard to
•c m •-
« N »
« m e
Z £ V






44
J
«
• ^
b
o

b
a.
e
o
 -o
44 e
••• n

c «
V «l
a u
0 S
b •]
a 44
c "3
• •
-S
— b
The persistence, toxicity, mobi
to bioaccumulate of such haza
_
























Tl

b
°^
3

«
b
a
3
e
4J
•^
U















1
e
0
b •
— e
» a
e —
V 44

41 *d
£ b

e e
b
44 "
— .
• C
V O
their constituents, and
The potential threat to human h
ment associated with excavati
^
C4

































































rcdiapoaal, or containment.


























































•B

W

14.
i .1
« e
•S '*
« Qt
red to develop two types of proc
Simplified assessments requirin
observation; and
• 44
3 —

«
at






o
44
,«

is a

O u
« • e
u at 44
• — J3
<• • 3
b •
0 3

sM
b 14. b
J ° •
' N
U • £
So
b — b
a o
b
•4. O —
O —
- o
44 e
c o *•
i'-o
a u v
O 3 •
— b «
^ • ^
41 ^ V
c "C t-


^^
u
^B,
S









i
w

"3 >
c «
9t V Q
91 U
* 01 V
u w
1 b «*•
> 3 O
1 V >
V u «
u o —
01 b M*
o a -44
* « 'S
c •*
•4 ^ A
Alternative methods for conAict
assessments using best availal
accounting for factors such a
to recover, etc.
^^























































^
c



-------
Legal Mandates for Ecological Risk Assessment
Page B-5





























u
I
M
U
(/)


|~
« e
o o
u H
• O
b
•1
«
e e
0
« « •
c *> •
owl
c v
b .C •)
SO >
*
3 O U
• V
«
u u e
v o

« <*• «
M « 1
1*1 • ••*
§• e
« •
u « «c
e • b
u • o











e
o
i
e
i
bb

u
e
.*
u


•
M
.5
T>
9
w
M


U
V?

b
«
e 44
i u
« <
U




•^
c
•

g|
f b
y >•

•
1 i

e o
«i
e £
a e
••4
•
U «
« «c
•*. •
u

0) *44
• °
• «
• *.
• •ri
O —
W
^ C
41 (•
o *a
§ S
cf
«1 0











b
3
3

• »4
b
at
<
1*4
O
>
b
•
•
U
M

>

m
• •4
•^

VI


^
£













l
e
41
N
>
<•

(•
e
•
w
•»4

U
•
3
X








*"*

b
O

;

u
•

•
«l
w
•
It.
e
O
•««
M
•
M
•


0!


•O
f





























C
a

•
V

2
b

propoi















































^
(Q


1 .

— e
u o

> 2

— X
3 >
y
b e
o

e —
V **4
— a
1 '
e
e •
« b
•" V
>


« 0
— o
3 «
li





'f
t i



8
4)
b
a
1
o

2
e
«

3
a

a
••4
W
U

b
91
a
u

a.


'«
f








-—
.M

£
«
£


•£ •§
3 >
^ •«•*
b •—
t o-

W IM
.5 "
(q
O
O

—4 U
v e
U 4)
e w
9 C
b aj
>
£

•£ »

j e
1 .
u •>
H



—
e
o
w
C
§
•
V
^
«
b
•c
V
tj

b
>
...
—
•
3 *
1 O
« w
» u
J "4
B
b -^
O —

w C
41 3
3 —

OC V


«
I
b
V
3
C x
<0 u
— *
u

o
e

.—
•—
V 1


i«

„ JJ .
• — w
^28

o > o
'i -o .-
a e 9
5 * S
a -
O £ 91

•o o
• £
91 .*
e •- «
o *** •<*
W ^4
U W .0

a a a
«

i o o
W -«4 -fl|
330
91 0 O
• a. a










































91
b
3

C s> O
•^ tq
" f 2


Si j:
b 3
> a
o.- i
c ~
— 5- y

3 •• <«l
e * 1!
0 0 -°
w oj
U O »• 41
•- O ».
•^ u e —
gn — —
e u •-•
«J C O ^
JS '** & C
v a -
- S •« •*
b C —
9> U
e e e -
1 2.2?
b u  e
b •*

1 I
O
u a
• e
•••
C 41
> b
'•S ^
i-2
^
U
O w
**- ^
n
« «
3 3

2£


^
c
ri







e
'^ -^
c e
o i

*•" ^
b 1 —


K 'o
c
o e

41
J3 <•
91 •
i I

i\i
tr a j





c
3
|
(A
U
*
e
 »
"5 c
3 "4
er >
b V
41 U
<• b
3
41 a
H-
If. 91
0 91
3

e •«
M 4)
a «J
o e
— 01
* —

e '


u
i








u
^^ •>•
O • 41

V Ite 44
n — b c «
*• a « •"
— 44 3

•o a n u o jj
• • 38 ° —

M •— O O (J J
— — a •- a

41 ^ >*« ^ Q n
3 u o -e
41 _. .- •- c
U £ 91 O
91 b ^ C -
c — 41 a •« o
o *. a •- c
91 — ••« u
" « -o JT .. c •
u js at «
41 • •- T: 3 44
- 14. . e a 3
U 41 J* 44 £ —
— « •- o a
41 JS 91 44 • >4.
"« e e b u —
44 14. O '"4 44 3 «
iw ^ 41 v a ' u
C fi b u b V
g « o c a *-
IM
U








4
U
V
• •«
b
U
>
4
o-

U
V
«

.—•
a
w
1
u.
'a


c
41
a
a
<••
V

2

^
a)
1








-------
Legal Mandates for Ecological Risk Assessment
Page B-6
















#
a.
w
K*
I
<<
j
5 -

G ^™
o
U *
^
' pd
« P
a s
a. **
s 3
u
M
J

M

•"
Ok
O
gg
4£
&

•j















•













k
j
01
g
•*•)
a
•*»
u


















1
• e
-1
O 0
o u
01 41


y ^*
•" •
£ k
S —
9
J















*i
VI O
*«4 *«4
a u
a •
«* in






.1
^
e
•i

25
il
is -2
• £
44
• or
41 e
k "U
3 3
14* «•
a •
44 >«4 a
X Sf.
= - 1
a k
c u c
251
3;

O 7
e t»
*.*
i 5
>«4 1
— 4t
£ e •
3
1 I I




4
U
.u
u

^
M
*4
3
U
. U, .- «|
— a —
e • -2 o
e a — o
• Ot « 44
33*'
•- 41 O O
v£ a o
• U • k
« • — a





•
k
a

c
V
e

44

^
3


k
W

*
M
fj
4VI



O

e
|

Q
MM

1

£
w*
e








-
44 e
— o

'— 44
£ U
•3.2
V
•o
e
•j
e
^
a
44
U
a
a
a 4i
*. u
-s
e •
.§2
u a
u «
a — •
-o S S
41 44 «




2
U
O
In
ft

(^
a

• ••)
£
w

•

a

e
a

.2
£
k

k
a

•
o
44
• 44
c e
o •)
'•4 44
M a
••4 — 1
•^ «>

•
P^
e
m











w
•J k
44
a at
II .
k u
ted aa haza
tubstantial
felines, et
•J O
at e «
0) •
j( 44 41
•Be*.
ii=
41 44 .
k C £

01 >•«
44 « 14.
• k •*
£ a —
M Af
• u •
41 •-
Si£
44 tl •-
iJo
(ft W W












u
e

•w
K
£
3

„
3
•8
«j
*4

£

<*•
O

e
o
w
^
e
Q(
••4
1

^
^
.M








0 .
O £
•— «
44 ->4
(9 144
at
a £
a «
k '^
e *«
<• £
e
O -4.
*•* a
44
u e
4) O
a w
k •
a —
3
« a
k a
3 a
a 1
x .2
41 "9
£ e

£ ^ '
ft e ••«
££••=
££ -

• " -o
z3 o5




3
k
41

k
a
«
e
a
••*
w
•

• <•!
f

.nl

e

3
**••
y


a

44
e
8 .
j: «
*» ot
••• u
._• ff
£ £
•J U
44 •
0| >n4
u •«

•
^0
^













o •
e
• k
U U
f!
V O
£
w •»
* *•*
V 4
» 3
w *w
4 4
O

k •
a

a e
— a
u
e •
••" 41
• z
k £
a •
i'-s

s
1
at
e
3
^
»

•
••j
u
M
O
h
a
e
o

•w
U

W
o
w
A

U
3
M
•(
«

%•
0

w
e «i
8|

a b
— 4»
41 «*
£ S
e u

£
C









U 44
O ••*
at oi >
C * k 44
a -o » SI'S
0 c u •- g
> •- 4> a o
U C £ 41 U
W O U 44
•- «! -0
e 4. . > c
••* «• *^ • «B
_ k • a
^ 4* y y M
41 C — « 14
k 41 at —
jf y e 41 o
' e » e 4i
•« o o ••» a
c 
W 4 £ V W
N U M at ••*
i " . S -
41 » £ £
^« 44 «J 44
.— Ot 3 • •

S — •* • e *
' a • • e
— saw «
b — U -£
So «. a > u
e a k 44
— a — c
c — > a
e • • — — —
••* « 9| 44 44
U 41 41 ••> 3 —
41 *4 a • v 3
*. b — £ k a
u u ' a a a




41
Ot
k
£
U
'•S

e

41

k

41
U.

<4.
O
e
a
••4
^
41
k

•o
e


44
e
8 «
a —
a b
— 41
41 "


U
<•£
e








14
k
V


« C
•J U
44 C
U
U • •
e v »•
3 k •«
a k •-
£ W 1
3
•o -
41 C •
ot « a
k 41
* •§ w
••* C
•e £ —
* "o

••« >4. V
^ k
'ill
S e S
W O M
•8 «.S
u e
44 «t J
3 14. a
X 41 •



• •
41 k
4« ^
W 41
U U
14*
•^ k

•— •
O
^ 44
C
« 41
41 k

41 U
k *

^

44
44
u e
v 2
«*• 44
41 41
M

a k
a
e £
a «
•- 3
19
e o
'•4 44
B

« a
44 "4
41 k
c a

u
^J
a









-------
Legal Mandates for Ecological Risk Assessment
Page B-7


















2
a*
^
I
M
M
1 i
j'
^ Bb
"!* w
ea H
i i
s
jj

2

E
fe
O
g
3

9
5
(a
























j


§
W
••4












|

"3 o
u u
ta •
^ ^^
••* •
3

«k M
^

••*
W
•J
*^J
y
^



2^
si
•<4 ••»
a •
* <"
B
.2
44
••4
«
J
•o
«

Lf
a>
•
• •4
'
•S
'»
g
•3
o
o
o
^
w
3
B
W
1
*.
S
8
«
4S

*






4)
• «M
U
1*
w
*
a

o
s
o

1.
44

.»•
M
W
b
1tJ
O

^J
s
b

^*
^
"^


a
u.
cZ




44
§|

'I8
4» 5
sS
'5 "S
*•
w >
•«» •
44
u w

a «
•o o
w •
M •

6 b
Si
3

1- *
o *• o
U b b
sss






































w
« o
0-
5 * *
O 3 <•
0 S
U b O
• O •
«• •
.5,2
r, S §
i s s
O 3
C — • •
*isi
c e
4] -2

-2 • '» I
s g .•
S'S'5
W b 44
• » 44 G
^ • O
44 • >t*
S O b 0

V V «
5 •« " :
S. b
I;i1



.
•
3
•
b
V
B
41
OC

>4
•
41
U
• •«
•
S


o

§
*—
^
_u
«4.
•
•
U
c
c
3
^










c
•o
*
c
i
41
• •w
• «4
w
•
s

•
e
E
W
4

i


w
al
3
•D
W
U
«
W

..
•
i
u

•
K

I4*
0

§
w
«
o
I4»
*
«
U
G
^
^
0





b
o w
*• «
u
s u|
sK
I'SS
• 0
0 - •
•O •> 41
S • C
(0
M > *
•- 8 S
e o
b ^ -^
J b 0
W "«

6 — •
O « W
••« W b
0 >•

'*. M
' " —
£ 3
'3 •- H
wi-
ll «
• o o
•o *. •-
b 44
o « ^
« 3 «















































•
§
e
o

>
e
w
c
o
•
u
•



































e
o

b •
£ 0
U W
w *.
* *
O fll
«
o
TJ 3
w <•
" S
3 •
•o <•
e w
O b
O S
3
W
•
« 3
W •

3 >•
« 2
^ ••« c

.- W b
«. >
a> «. B
• o w
S 3 4J




«
...
3

2

3
O-
«
b
w
'•
b
W
a

w
M
3
•

C
8
u
i
M
W


3
^




„
^
• •4
• W
1 I
— a
c
« ^
•o 2
e c
. |
« C
o I .§
« — >
' «
b C -B
3 I m
f
w - s
u S 3
b w 3
• —
« — e
— 0 u
C • *
i - u
•Ob S
• B
- v e

m ••> c —
• 9 = 2
o B 0- i
w
e
o o
•
<













M
E
b
O
44
•M
C
o
*
e


u
b
•
W
•
W


e
CM




C
w e
44 W .* W
« J « W
i 44 — J
• 44 W b W
44 • — i
O B W V
W *? ** *-* ^
*** -^ *» C »
•- 'w « 3 1 b
W — C
£ — 3 "O O JC
44 41 « •- 3
^ B b > 0
e w - o
C J3 W C
C •- 0 O «
fl > • U 9 3
e c w 41 —
•- w b e o •
S a— e >
« •« w w
44 C 0 « b
C (• 44 W W b
0 O »4. O
30 41 •-
44 b •« 4
O 3 « W 44
i b <44 . •
• 44 <4. « •«
WO « •* »
b B ••" 44
g.s -3^.2.5
"i 3 3 S a
•to C 14. ° S b

en > o o «
•4 ti "B«w
— b b — W £
O • 44
£ W •
O 4( J» • -0
3 • — B












1
*^
w
«
3
«
W
at

'o
w
e
u
a
o
w
>
£


„,
"










^
.-
'2
w
«
3
••
O
• •4
•
§
B

3
^
O
.^
b
M




































-------
                                                                 TABLE B-l  (Continued)

                                              SUMMARY Of THE LEGAL MANDATE POi ECOLOGICAL ASSESSMENT (EPA>
L.gi.l.Hon
Applicable
Section(s)
Activities For Which Ecological Assessment
           Mquir«d/««coi««d.
 (0
 S1
 n
 n
 n
 o
 o
OQ
 H-
 o
 to
                                                                                                                                                             (a
                                                                                                                                                             7?
(a
(a
IB
(a
ca
0
                                Remit criteria for dumping radioactive waste  (two  yean
                                after date of enactment).
                                                                               Dumping mitt be preceded by baseline studies of proposed
                                                                               site and surrounding environment.

                                                                               Applicant nust carry out a comprehensive monitoring plan
                                                                               that includes fish and benthic anisial  sampling.

                                                                               Applicant must aiaess analysis of  environmental impact on
                                                                               human health and welfare and marine  life.
                202(a)<2)
                                Research on ocean dumping
                                                                               Comprehensive  research on ocean  dumping  is required to
                                                                               define  and quantify  the degradation of the marine envir-
                                                                               onment  and assess  the  health  of  the marine environment.
                                                                                                                                                             p>
                                                                                                                                                            00
                                                                                                                                                             a

-------
Legal Mandates for Ecological Risk Assessment
Page B-9



















a.
M
i
in
ca
W
«9
ca

d
3 -
i 1
| jj

s*» )•*

i 1
i 1
H _,
3*
Oh
O

c
5
S


s




























b

a
.1
-
£












B
•

Mp
4
"*
eh EcoloRtca
d/ftecoa-Mnd*
••* •
f i
o •

"
(•>
tjf
*•»

*J
••4
w
.g





II
«• w
e> u
a •
< ca
§
—

M*
.•
«£
S>
J
e

of
V
2-Q
3 S
9 4 M«
K d
of 44 b
b 6 3
41 44
— « •
one
e b
9 a 4i
— •
44 41 4)
"j .c .e
C 44 44
41 T5 w
£ C U
MM
JJ .MM
3 41
— b >.
. • a
— e
(• 44
2 "9 -
i ; ;
e — —
9 — —
o -• >
V 3 —
-a tr o
9 —
44 • »
U 9
b « 44
9 9 C
Q 9 —
• U 9
u. 4i a











d
41
••*
b
3
U
e
41
e
1
*
G
o
••4
W
4


o


^
4|

.5
•
S
s
m
e

-
V
3
c
'Ml
c/: e
at 9
0. U
Z —









•
.«


3
T
CJ
at
9
O
0
41
S
4
U
b
§
8










































S 1
9 —
— — MM
44 • O

- • e
'" <• C
b 9
U > —
« J3 —

st V V
u e o
"i '» a
o —
C 4* b
0 • 0
tj MM
E s — i

4i 44 a e

C « i| c
.C JT O
U 41 44 b
41 U —
" III
•fl b — "
•MI o 44 41
> *» O JZ
9 b • —
b 41 b
a ft o -e
e
• OS
4) « —
• > M •
S4I • 4t
— "* C •*
— 4* a «
I's?!





v
%
3
••4
"o
«

1*
o

t d RU i de 1 ine
w
•
«
M
M
3


«j
ay


•

•o

IS
9 •

> e

~
|





<
Of
u
at
b
V

•8 '
*
.C 44

b «
O 41
S*
b e
" 9
9i a
•^ 3
e Si
S *•
' 9

41 >
4Z t-I
44 W
U
— 41
44 O
§ a
•w •
.n e
x 8
O 41 •
a • e
•M 1 C
aceswnt
ned that
e enviro
sr-ss







I
•Ml


e

ardous waste
M
•
U

Mrt
A

O •

e •


4 e
M 9
b —
I \
44 b
3 9
«: MM
2
g
«







"C (
O C
j= O
W k.
r; -
e —
« 4» U
en —
 >
b — e —
N u n
• 41 b e
.: 44 o v
9 MM 0.
b b O

"U SB
« 9 3 «
0-9
a u -
— 5 • —
•Q 9 —
•*) 01 44 —
B 6 J3
3.218





B
*
5
1
u
m
N
2
o
1
••4
•o
•o
e
<*
B

^

b
O
UM
C
g

JJ
N
b
O
44
*
^
O
o
"








•fl
— o

o ji c
a I ji

w « c
_.- „
2, S
e
44 « J-
U — 44
41 M
.» c "
3 > X
en ••*
•X (J

> > 3
S -0 a
• • -c
41 (fl w
44 9
* 2 °

0—44
^ O
b • 41
« e -
sted haz
ohibitio
not pro
2 a- 2








.
W
•
•V
9
of hazsrdou
^
B
9
44
J)
—
£
0
b
a



|
•*•
^J
-,
e
J
01
§











^ «J
(B C
B 8
b C
41 0
short-t
he envir
41 44
.2-0
e e
— a
is
o "5
44 41
•*•=
-3
9 i
•« 3
41 Ji
1 2

44 41
0 b
if
andards
OK- tern
w o
er. M






w
CJ
3
V
w
«
;
tandards for
ons
• —
44
44 —
E J3
12
44 e
• w
4i a
b
44 MB

MM •
9 0
a
44 •
= '^
a -e
0 E
U —
>
22
-5
e
c








•o
c
4

CB
41 •
C «
o human
oundment
M
41 41
^ •
b
— 3
V «
44 Q(
c e
v —
44 W
O *
a —
X
41 41
" 'o
<4< C
c 1
st accou
e enviro
I 5





E
i
I
4
MM
b
3 •**
* «
c -~
ss on existi
under 1005 (
« e
b 9
»•"
e -
u •

0 X
44 4>

4« 9
b 44
9
a 44
41 U
b tt

e 3

u 44
3 C
** 8
-
o
c










s
••«
a »i
CUB

B >
improve
e the ad
earl ier
BUb
O 3 O
9) 41
41 b >>

-
«> 3
£ U
U 0 .Ml
U — u
E a
s s .
u •
9—44
U 41
•6 4 M.
„ b y.
3 — —
41 • u
b 9 E
-Jl
b'-S §
a -0.5
B >
e • c




3
3
h*
JJ
«
-C
O
at
C

«-*
fll
41
V»
nrf training
•1
C
o
u
^
U
4J
01 W
c e
8 8
u 41
•« «
> e
•s a
b
• 4*
V 44

at ?
~
C
o
90























•
•S
e

-------
                                                                 TABLE B-l  (Continued)

                                              SUMMARY OP THE  LEGAL  MANDATE FOB ECOLOGICAL ASSESSMEKT (EPA)
                                                                                                                                                              sr
                                                                                                                                                             04
Legislation
                 Applicable
                 S«ction(a)
                        Activities Por Which Ecological AsaeeaaMnt
                                   Required/Recommended
                                                                                                                  Citation Summary
                                                                                                                                                             rt
                                                                                                                                                             »
                                                                                                                                                             (A
                                                                                                                                                             in
                                                                                                                                                             O
                                                                                                                                                             o
                                                                                                                                                             M
                                                                                                                                                             O
                                                                                                                                                             OP
                                                                                                                                                             H-
                                                                                                                                                             O
                                                                                                                                                             to
                                                                                                                                                             ut
                                                                                                                                                             ff
                                                                                                                                                             (A
                                                                                                                                                             (A

                                                                                                                                                             (A
                                                                                                                                                             (A

                                                                                                                                                             g
                                                                                                                                                             3
                                                                                                                                                             rt
RCRA
(cont inued)
SDUA
TSCA
                 8002U),(m),
                 (n),(o),l (p)
                 lA27(d)
4(a)
                 Ub)
                 S(b)
                Special watte studies
                Development of criteria for the identification of critical
                aquifer protection areaa.
Testing to develop  data with  reapect  to health  and
environmental effecta of substances or mixtures manu-
factured, distributed in commerce, proceaacd, used,  or
diaposed of.
                                Establishment  of  standards  for the develop*
                                data  for  tubatancea  or  Mixture*
                                                                            :nt  of  teat
                                Notification  and submission  of  teat  data required for
                                manufacture of  a new chemical  aubatance or processing
                                any chemical  aubatance  for a new use.
                                Exemption  from notification  require
                                •arketing  purposes.
                                                                      nts  for  teat
                                                                Each study  matt account  for  the  potential danger to huawn
                                                                health  and  the  environment  from  specific waste management
                                                                practices.

                                                                Environmental costs  and  benefits have  to be considered
                                                                during  identification  of critical  aquifer protection areaa.
Required only when insufficient data exists  for  the sub-
stance or mixture, to determine if an unreasonable risk of
injury to health and environment is present.
                                                                               Standards for development of test data for substances or
                                                                               mixtures may be preacribed for:

                                                                                 o  Environmental effects
                                                                                 o  Chemical characteristics
                                                                                 o  Methodologies for determining effects

                                                                               Test data required must show that the new substance or
                                                                               new use will not present an unreasonable riak of  injury
                                                                               to health or the environment.

                                                                               Must show that the msnufacture, processing,  distribution
                                                                               in commerce, use, and diaposal  of a substance will not
                                                                               present any unreasonable risk of injury to health or the
                                                                               environment.
                 6(e)
                                Authorization  to manufacture  or  use  PCRs  in a manner
                                other  than  totally  enclosed.

                                Substance or mixture  being  manufactured,  processed,  or
                                distributed in commerce  for export
                                                                               Must show that manufacture or use will  not present any
                                                                               unreasonable risk or injury to health and the environment.

                                                                               May require testing (pursuant to .Section  A of TSCA)
                                                                               if unreasonable risk may be present  to  health and the
                                                                               environment.
                                                                                                                                                             09
                                                                                                                                                             i
                                                                                                                                                             h-1
                                                                                                                                                             O

-------
 Legal Mandates  for  Ecological Risk Assessment                      Page  B-ll

      Finally, Section 311 of CERCLA requires basic research of hazardous
 substances  involving  evaluation of methods to reduce the amount and toxicity
 of hazardous  substances.

 1.2  Clean  Air  Act

      The  purpose  of the Clean Air Act is to protect and enhance the quality of
 the Nation's  air  resources  through the prevention and control of air
 pollution.  Although  the primary objective of the Clean Air Act is to promote
 the public  health and welfare, several provisions in the Act require
 evaluation  of environment impacts.  Subchapter I, Part B, Ozone Protection,
 encourages  studies  to assess effects of changes in the ozone layer upon living
 organisms and ecosystems.   Subchapter I, Part C, Prevention of Significant
 Deterioration of  Air  Quality, requires that the criteria for reclassification
 of protected  areas  and the  redesignation of preconstruction requirements for
 major emitting  facilities include an assessment of environmental effects.   The
 Act does  not  specify  the methods for or the components of an environmental
 assessment.

 1.3   Clean  Water  Act

      The  objective  of the Clean Water Act (as amended by the Water Quality Act
 of 1987)  is to  restore and  maintain the chemical, physical, and biological
 integrity of  the  Nation's waters.  One of the National goals established by
 the Clean Water Act is to attain water quality that provides
 for the protection  and propagation of fish, shellfish, and wildlife.  The
 objective and goals of the  Clean Water Act are achieved  through the control of
 discharges  of pollutants to surface waters.

      The  requirements for an ecological assessment under the Clean Water Ace
 fall  primarily under  Title  III, Standards and Enforcement, and Title IV,
 Permits and Licenses.  Under Sections 303 and 304 of the Clean Water Act,
 States and  EPA are  required to develop standards and criteria, considering the
 use and value of  waters, and must assure the protection  and propagation of a
 balanced  population of shellfish, fish, and wildlife.  In addition, States are
 required  under Section 305  of the Act to provide EPA with a water  quality
 inventory.  This  inventory  must include an analysis of the extent  to which the
 quality of  State  waters provides for the protection and  propagation of  a
 balanced  population of shellfish, fish, and wildlife.

      Section 307(a) of the  Clean Water Act requires EPA  to establish a  list  of
 priority  pollutants.   In adding to or revising this list, EPA  must account for
 the toxicity, persistence,  and degradability of  the pollutant,  and the
 potential presence  of affected organisms and the effects on  these  organisms.
 Under Section 311(b),  EPA is required to designate  as hazardous  those
 substances  that present imminent and substantial danger  to  fish,  shellfish,
wildlife, shorelines,  etc.  Effluent limitations established for  thermal
discharges  under  Section 316(a) of the Act must  assure protection and
propagation of a  balanced,  indigenous population of shellfish,  fish,  and
wildlife.  Waivers  or exemptions from standards  established  under the  Clean
Water Act (e.g.,  301(g) and 301(h)) may not be  granted  unless  it  is shown that
 the variance will not interfere with the maintenance  or  attainment of  water

-------
 Legal Mandates  for  Ecological Risk Assessment                      Page B-12

 quality that  assures  the protection and propagation of a balanced population
 of shellfish, fish, and wildlife.

      Under  Title  IV,  EPA is required to establish control over discharges to
 the Nation's  waters.  The criteria for discharges to oceans under Section
 403(c)  must consider  the effects on marine life, including changes in marine
 ecosystem diversity,  productivity, and stability.  Section 404(c) of the Act
 requires an assessment of adverse effects on the environment including impacts
 to shellfish  beds,  fishery areas, and wildlife prior to approval of discharges
 from dredge and fill  activities.

      Several  provisions under the 1987 Amendments to the Clean Water Act
 require an  assessment of environmental impacts.  Under Section 304(a),  EPA
 must develop  methods, including biological monitoring and assessment methods,
 for establishing  and  measuring water quality criteria for toxic pollutants.
 The 1987 Amendments to the Act also establish, under Section 320(b),  an
 estuary protection program that includes the development of a management
 conference  to implement the program.  The purpose of a management conference
 is to collect and assess data on toxics, nutrients, and natural resources
 within  the  estuarine  zone to locate the causes of environmental problems.

 1.4  Federal  Insecticide. Fungicide, and Rodenticide Act (FIFRA)          '"

      The objective of the Federal Insecticide, Fungicide, and Rodenticide Act
 is to prevent "unreasonable adverse effects on the environment" from the
 use of  pesticides.  Although ecological assessments are not explicitly
 required, the components for protection of the environment are generally
 provided for  through  definitions provided in FIFRA.  Specifically, the
 environment is  defined under FIFRA to include "water, air, land, and all
 plants  and  man  and other animals living therein, and the interrelationships
 which exist among these."  Unreasonable adverse  effects on the environment are
 defined under FIFRA as any "unreasonable risk to man or the environment,
 taking  into account the economic, social, and environmental costs and
 benefits."

      Section  3  of FIFRA establishes the procedures by which a. pesticide  is
 registered. Section 3(c) specifies that prior to approval of a. registration,
 an assessment of  the  impacts of the use of a pesticide on the environment  must
 be  performed by the Administrator.  Under Section 3(d), the potential  for  a
 pesticide to adversely effect the environment if improperly used  is  the
 primary factor  the Administrator must consider when classifying pesticides for
 general or specific use.  For pesticides not previously registered,  the
Administrator can issue an experimental use permit under Section  5 of  FIFRA
 that would contain conditions for use.  The Administrator may require,  as  a
 condition to the  permit, studies to detect whether the pesticide  under the
permit  may cause  unreasonable adverse effects on the environment.

      In addition  to setting forth criteria for pesticide classification and
use, FIFRA specifically calls for assessments of environmental  effects of
pesticide use.  For example, Section 20(c) of FIFRA requires,  as  necessary,
monitoring of air, soil, man, plants, and animals  to assess  incidental
pesticide exposure.

-------
 Legal Mandates for Ecological Risk Assessment                      Page  B-13


     Finally, Section 25 of FIFRA provides the Administrator  with the
 authority  to prescribe regulations to control the development and use  of
 pesticides.  These regulations must account for the differences  in
 environmental risk and data for evaluating such risk between  agricultural  and
 nonagricultural pesticides.

 1-5  Marine Protection. Research, and Sanctuaries Act (MPRSA1

     Title I of the Marine Protection, Research, and Sanctuaries Act
 establishes a program to regulate the disposal of waste in the ocean in order
 to protect human health, welfare, and amenities, and the marine  environment,
 ecological systems, and economic potentialities.  Section 102 of MPRSA
 requires an assessment of the impacts of ocean dumping activities on the
 environment prior to issuance of a permit.  According to Section 102(a), some
 of the factors that the Administrator must consider in issuing permits for
 disposal are the effects of the ocean dumping activity on fisheries resources,
 plankton, fish, shellfish, wildlife, shore lines and beaches; potential
 effects on marine ecosystems; and potential changes in marine ecosystem
 diversity, productivity, and stability.  Under Section 102(c), the
 Administrator can designate recommended dumping sites or times in order to::
 protect critical areas.  This designation is to be based upon the same
 considerations required under Section 102(a), including in part the effects of
 the dumping on fisheries resources, plankton, fish, shellfish, etc.

     Title II of the Act requires comprehensive research projects on the
 effects of ocean dumping on marine environments.  Section 202(a)(2) calls for
 the assessment of scientific technologies to define and quantify  the
 degradation of the marine environment, the assessment of the  capacity of the
 marine environment to receive materials without degradation,   and  continuing
 monitoring programs to assess the health of  the marine environment.

     Title III establishes the National Marine Sanctuaries Program.  According
 to Section 303(b), the criteria for determining whether an area will be
 designated as a sanctuary include the natural resources and  ecological
 qualities of an area, such as biological productivity, maintenance  of
 ecosystems structure, and maintenance of ecologically or commercially
 important or threatened species.  The present and potential  activities  that
 may also affect the natural resources and ecological qualities  of an  area must
 also be considered.

 1.6  Resource Conservation and Recovery Act  (RCRA)

     The objectives of RCRA are to promote  the  protection of human health and
 the environment and to conserve valuable material  and  energy sources.
Although neither the Act nor its legislative history define  protection of the
 environment, there are several provisions under RCRA that could necessitate  an
 assessment of environmental impacts.  Section  1008  requires  EPA to develop
 guidelines that provide levels of performance  of solid waste management
 practices that would provide for the  protection of public health and the
 environment.  Requirements to protect the environment  are contained in various
 subsections of Section 3004, Standards Applicable  to Owners  and Operators of

-------
 Legal  Mandates  for  Ecological Risk Assessment                      Page  B-14

 Hazardous Waste Treatment, Storage, and Disposal Facilities.   Specifically,
 determinations  by EPA for the prohibition or regulation of various solid waste
 management practices and associated hazardous wastes must account for
 protection of the environment.  For example, Section 3004(b)  prohibits the use
 of underground  mines for the storage or disposal of hazardous wastes unless
 EPA determines  that such placement is protective of human health and the
 environment.

     Under Subtitle H of RCRA, various studies are required to conduct
 research, demonstration, and training related to solid waste management
 practices in an effort  to improve practices and reduce adverse environmental
 effects.

 1.7  Safe Drinking Water Act (SDWAV

     The purpose of the SDWA is to assure that all public drinking water
 systems provide safe, high quality water.  Although the primary goal of the
 SDWA is protection of public health, one provision requires an environmental
 assessment.  Section 1427 of the Act requires that EPA develop criteria for
 the identification of critical aquifer areas that should receive special
 protection.  In developing the criteria for this identification, the       .
 environmental costs and benefits must be considered.  The specific factors'
 associated with the assessment of environmental costs and benefits are not
 provided for in the Act itself, nor are they discussed or interpreted in the
 legislative history of  the Act.

 1.8    Toxic Substances Control Act (TSCA)

     The objective of TSCA is to protect human health and the environment
 through the regulation  of the manufacture and use of chemical substances.  Th
 specific methods that are necessary to assure protection of the environment
 are not provided in the Act.  Environmental assessments could be required
 based upon the  definition of environment provided under the Act.  The
 environment is  defined  in TSCA to include "water, air, and land and  the
 interrelationship which exists among and between water, air, and land and all
 living things."

     One of the primary means of protection established under TSCA  is
 requiring test  data under Sections 4 and 5.  This test data must show that the
 manufacture, processing, distribution, use, and disposal of substances  will
 not present any unreasonable risk of injury to health or the environment.
 Section 4 of TSCA requires the submission of test data for substances that
have been included on the priority list, established pursuant to  Section 4(e).
 Section 5 requires notification of the intent to manufacture or  process any
 chemical substance.  For the manufacture of a new chemical substance or new
uses of an existing chemical substance, test data must be  submitted along with
 the notification.  Exemptions for notification to manufacture or process a
chemical substance can be granted under Section 5(h) for  test marketing
purposes.  However, this exemption can be granted only after  it  is
demonstrated that the manufacture or use of the substance  will  not  present any
unreasonable risk of injury to health or the environment.

-------
Legal Mandates for Ecological Risk Assessment                      Page B-15

     Section 6(e) of TSCA requires the establishment of regulations to
specifically control the manufacture and use of polychlorinated biphenyls.
Under Section 6(e), the Administrator is authorized to permit the manufacture,
process, distribution, and use of polychlorinated biphenyls in a manner that
is not totally enclosed only if it is shown that the practice will not pose an
unreasonable risk of injury to health or the environment.

-------
 Legal Mandates  for Ecological Risk Assessment                      Page  B-16

      2.0  STATUTES AND DIRECTIVES ADMINISTERED BY OTHER FEDERAL AGENCIES

      Table B-2  provides a summary of ecological assessment requirements  of
 environmental legislation administered by Federal agencies other than EPA.  A
 brief description  of  the ecological risk assessment requirements for each
 statute  and directive is provided below.

 2.1   Coastal Zone  Management Act of 1972

      The purpose of the Coastal Zone Management Act of 1972 is to encourage
 and  assist States  to  develop and implement management programs to protect the
 land and water  resources of the coastal zone, considering in part the
 ecological values  of  the coastal zone.  Although ecological assessments  are
 not  specifically required under this Act, it may be appropriate for an
 assessment of ecological risks to be performed as part of a coastal management
 program  established pursuant to the Act.

 2.2   Endangered Species Act

      The objective of the Endangered Species Act is to conserve the ecosystems
 upon which endangered or threatened species depend, and to conserve the
 species  themselves.   In determining whether or not a species is considered-.
 endangered or threatened, Section 4(a) requires that the present or potential
 destruction, modification, or curtailment of a species habitat or range, and
 other natural and  manmade factors affecting the existence of the species, be
 assessed.   Further, under Section 7, any Federal agencies that undertake
 activities  that may jeopardize the continued existence of an endangered
 species  must perform  a biological assessment to identify the endangered
 species  which is likely to be affected by the activity.  The specific form of
 the  biological  assessment is not specified in the Act.

 2.3   Executive  Order  11988. Floodplain Management

      Executive  Order  11988 requires that agencies of the Federal government
 take  actions to reduce the risk of flood loss; minimize the impacts of  flood
 loss; minimize  the impacts of floods on human safety, health, and welfare; and
 restore  and preserve  the natural and beneficial values served by floodplains.
Although ecological assessments are not specifically required, any major
 Federal  actions involving floodplains must be accompanied by an environmental
 impact statement as required under the National Environmental Policy Act
 (discussed further below).

 2.4   Executive  Order  11990. Protection of Wetlands

      Executive  Order  11990 requires that Federal agencies  take actions  to
minimize  the destruction, loss, or degradation of wetlands, and  to  preserve
and enhance the natural and beneficial values of wetlands.  According to
Section  5(b), prior to any Federal activity involving wetlands,  the
appropriate Federal agency must consider the effect of the  activity on  the
maintenance of  the  natural system, including productivity  of  existing  flora
and fauna, species  and habitat diversity and stability, hydrologic  utility,
and fish, wildlife, timber, food, and fiber resources.

-------
Legal Mandates for Ecological Risk Assessment
Page B-17




















o>

A
£
™?
























b

3
§

JJ
.2
W













W
i

•4
sl
II
0 0
V U
M «J
••* *
£ M

0
•
-
•W





• *•*
||
a o
a •
a
o

**
41
9
at
«
J


•o-l,
c •«•
41 «
« c
C ^ 9
I S °

IJ5
'•rf M
T) u- c
c a •«
a S at
_0 3

41 41
•3'S I
41 M
> *
•M «
f S
• u
V O 41

. s!
• e
at •
a «
^ b U
a b
a
w a
e •
t 2
41
3 at b
e S «
cS 3 5











^
U
I
"S
I

•
w
41
I

n
O
C  r»
N e 9>
a* ""
"n 8 •*•
w at a
« C w
a 
e
b
whcthc
ecie*
|

e

1
to
Is

^
5
T5 O
41 <
b
al 4i
e •••
•3 i
c a













•
41
w
M
41

41
I
W
§
w
u
01



e
"
«*•
*


































«4M
o

*
u
e
e
V
M
V
W
a
%

l
•
41
U
41
a
^
41
b
e


c
41
e

"*


•o
41
3
C
w
e
o
u
41
£
41
N
•S
b
«
a
a
3

•
• *4
.*
U

«M4
fl|
In
•8
«
a.

g











e £
8 »
en *
« «
« u
en v
* a
0
"n "0
u «
»M U
V V
5 ?
2 •§

^s e
, "
«
v «
^
..t;
u c ^
•; -8 *
.- .M 0
« 4)
08*-
*• ^3
• 41 41
b b J3
41 *•*
•5 3 a
41 7 u
b. 4)
b >>
41 41 41
8*.-S
9 ->
a j —








d specie*.
«
41
at
e

e
e
«

a

g
«
u
•
••«
x
41













C
* tt
ones
3 > *J
•c — _ <«
e « o «
e
01 ^ -^ W
en u
'i '.s 1 1
ttr-
§c u —
41 • •)
— J3 u


O C b fi
" <» « e
•8 o
« .- 41 b
U b >
« 3 b C
1 S '« e
41 41

« 'a S
41 41 C J) Ul
» > — a z
8 41 — • b
C 41 ' • "8
— b O 3 C
8 a o 1 3
O "C <*- » "C
u e e 41
4 > — b
•0 J3 « —
41 41 — 3
b b •« a ff
— 9 41 * 41

Of b • ». •



• • «M
V f *•
e u o
••« 4? .
3 41 *
— tl. 41
U U
c i*. e
- « g
» at ••«
c c *-
nit ftoodplai
and di»po*i
««;
undertaken,
'> at'i >
-> e — —
c a) u b
••" C « 41
• >*. -o
« "5 S.
•_ . e
— e e
> •- « —
w .- e —
«i 5 •• a
U b
— < a.
tq
..
^S — fM

^J
-S

X — C
3- n g
— "a 4i
•e at
• o «
COS
• -* m
U to. X





























a
•fl

^J W
e »«• •
:.i5J
2 " u *
C * 8 •
«0 C —
b a
« a u
* - 3 *
o n .a 41
ion and iapr
ctivities an
, including
land recourc
u * S-o
S •• 3 «
** * T> "
• ^ G ^
!!?- 2
at '
' c-S S
• w U b
si^ s
a
u


















































•
>•*
>
centine acti
••*
1
g|
g"
•^
at
















•o .
C b C X
o ji M. D •
'u .- ° u
•5 c o •« >
« o c u >

^ a 41 at « —
CO " "
9 41 • "" C
• 3 41 • «. at
— 4i « e "O -«
b o e o
C •** «• b
e . 9 M *7
5 c « « >
••• o > > b a
•j M .- a, _ .
3 U > • *ib ^
b 3 — C w
" b u o at —
• ** u u c •*
«« * — —
e at M £
O 41 C • •
41 y X — ••• w

41 O U •*« C
H b can
— a w —
B •« u > >
e a. 

w s "£ • •? *S
"V 9 0
••* tt « U 
*** c *** a
•<* b
^ S c S
0 O. 41 —
v~ ••* 4 "C
u ^ WC
S_ *• •
•e «
E ..•* G
at « « c o
C 41 3 •«
> at w > u
— e — —> a
o — — — i
C • U b •
'- 5^-81
• 1 41 U
V ^0.
— - C '
••* e e w
> •••••••
•^ b T) ^ '^
w •- S •- •
U 3 « > •
<• cr-> a •
U b
— < a.
<•
b
41

• JO

S =•?
a> o e
— •- «
u w
41 41
• - 3
c a
• b »*.
u a. o

-------
Legal Mandates for Ecological Risk Assessment
Page B-18


































^^
•Bf
3
e
•a4
44

3
w
«

•1
I












































M
U
s
3
d
g
C3
tb
fel
g

M
01
Cfl
8
3

^
2
s

s
LEGAL MANDATE POft EC
w
•E
•hi
O
>•
|
£
M





























X
b
i
£
g
w
4*

••4
O











w
a

Q
0
•

M ^
For Uhich Ecologica
tequ ire d/tecoaBao da
5
w

u
4<




.O V
II
a o
a •
«* M

§
•«l
w
•
a(










.

V
b
|
S

w
V
.0
••4
<•*
•0
e
Q
a
44.

e

b
i
4*.
^
—
'5
.!„„

wee
u • «j
v
14. • at
• we
•JO —
b w 3
at at
o ^ •
b V b
a w

•S I at
ederal activitiea an
including but not li
nd reaourcea plannin
activitiea.
b. •
'*• at
at « e
e • ^ ••»
"4 3 • «

3 C — O
j"2-


«n





§ c -3 ^
o> o e «
Z-^ g
. w 3 e
coo
• b »4 
"^ e
•« «4
•«
**4 U
3 3
^
e «
ll

U. w
«
H

3 at
v e
• ••*
U 9
••4 •«
11

O b
9 4^
o o

• -o
deter aine the effect
nduatrial waatea, an
•^
o
• 3

— ^
W b

w
• -
> e
e •-


i^










e
o

w O
•
e «
'•4 CJ
I e
b •
« e
»'i
5 •
«


^
a b
o
3t w
' "4
3 —
1 1

— 41
2 S
•
.2 -8
W b
• JI •
at "O al

S • ^
> *•
— OS












•
«
*••
• •4
2
3

•
0
•
w
A
3












41 1
I C b
41 41 «


BOO


£1

e





<
a.
u
z























•
a
o
•^
u
^4
•
b
«
h.
£






































• •

X 41
4t ^
b X
3 •

• U
41 —
•3 O
u O
• U


• 0
e w
o
••4 9t
w e
» ••«
w _ .
41 b w
> "4
C • —
• 3
y -*
a • ••
"C c •
0 -o c
0 e I
o • c
r .2
•e ^ •«
4) U >
b b C
3 41
w • •«
at b ai



44
b
i

•*4
••
|

*+ x
annual Environpenta
Environmental Qualit
2 c
w 0
<*4 ««
O •••
e ^
|J
b 41
• S
• **
b >
a. ^

e
cs








e
at *
S '
••4 • .
» b •
O V 41

T-C!
41 b
41 £ 3
b u a
^ 3
« e
b O
41 O W
b b
C — «

• e
« 3 O

> b —
— 41 O
b w e
TI 52
« 41
41 w

41 w •
• U w
41 U >
> 0
b b b
• f
I2»
285
'^ I4B
- •S «2
— e
a. u w












u
"o
a.
o
§
• a*
»4
*
*o
2

£
"
b
41
• •4
' at
c
•o 'e

••* u u
3 « •<

-------
Legal Mandates for Ecological Risk Assessment                     Page B-19


2.5  Fish and Wildlife Coordination Act

     The objective of the Fish and Wildlife Coordination Act  is  to assist in
developing and protecting all species of wildlife,  wildlife resources, and
wildlife habitat.  Several sections under this Act  appear  to  require  an
ecological assessment.  Specifically, Section 2 of  the Act requires a report,
for projects involving impounding, diverting, or controlling  waters,  which
describes the damage to wildlife attributable to the project  and measures
proposed for mitigating or compensating for these damages.  In addition,  the
report has to include an estimation of the wildlife benefits  or losses to be
derived from any new project for the control or use of water.   Under  Section  5
of this Act, the Fish and Wildlife Service and the  Bureau  of  Mines  are
authorized to perform investigations to determine the effects of pollutants on
wildlife including the determination .ef standards of water quality  for the
maintenance of wildlife.

2.6  National Environmental Policy Act (NEPA)

     The objective of NEPA is to preserve and enhance the  environmental
quality of the Nation.  To ensure that the objective is achieved, all Federal
agencies are required to submit a report, for proposed legislation or major
Federal actions that could have a significant impact on the  environment,  that
describes the environmental impact, any adverse environmental effects, etc.
The Act does not specify the form of the analysis necessary,  nor does it
define environment.  However, these studies usually include  an analysis of the
impact on soils, geology, hydrology, air quality, and wildlife.  The Council
on Environmental Quality, established under Title II, is also required to
conduct investigations, studies, surveys, research, and analyses relating to
ecological systems and environmental quality.  The Council must present an
Environmental Quality Report to Congress on an annual basis.   This report sets
forth the status of the environment, including the air, marine, estuarine, and
fresh water environments, and forest, dryland and wetland environments.

2.7  Wild and Scenic Rivers Act

     The goals of the Wild and Scenic Rivers Act are  to preserve selected
rivers in their free-flowing condition,  to protect  the water  quality of such
rivers, and to fulfill other vital National  conservation  purposes.   The Act
designates the initial components  (i.e., rivers) of  the National Wild and
Scenic Rivers System, and prescribes methods  and standards according to which
additional components may be added.  Although  there  is no specific requirement
for an ecological assessment in conjunction  with the  methods  and standards
provided, the stated goals indicate  that ecological  impacts  should be
considered under this Act.

-------
              APPENDIX C




ECOLOGICAL ASSESSMENT METHOD SUMMARIES

-------
                              TABLE OF CONTENTS

                                                               Page

Introduction	  C-l

1.  Methods/Assessments Developed Under CERCLA
     1.1  CERCLA Type A Natural Resource Damage Assessment  Model
          for Coastal and Marine Environments (DOI 1987a)......  C-2
     1.2  CERCLA Type B Natural Resource Damage Assessment
          (DOI 1987b)	  C-10

2.  Methods/Assessments Developed Under the Clean Air Act
     2.1  Review of the National Ambient Air Quality
          Standards for Ozone:  Staff Paper (EPA/OAR 1986)  ....  C-14
     2.2  An Assessment of the Risk of Stratospheric
          Modification; Submission to the Science
          Advisory Board (EPA/OAR 1987)	  C-17

3.  Methods/Assessments Developed Under the Clean Water Act
     3.1  Guidelines for Deriving Numerical National
          Water Quality Criteria for the Protection
          of Aquatic Organisms and their Uses
          (EPA/OWRS 1986) 	 C-22
     3.2  An Approach to Assessing Exposure to and
          Risk of Environmental Pollutants (EPA/OWRS 1983)	 C-25
     3.3  Permit Writer's Guide to Water Quality-Based
          Permitting for Toxic Pollutants / Technical Support
          Document for Water Quality-Based Toxics Control
          (EPA/OWRS 1987, 1985) 	 C-28
     3.4  Biological Criteria for the Protection of Aquatic
          Life (Ohio EPA 1987a, 1987b, 1988)  	 C-32
     3.5  Niagara River Biota Contamination Project:  Fish
          Flesh Criteria for Piscivorous Wildlife
          (NYS/DEC 1987) 	 C-39

4.  Methods/Assessments Developed Under FIFRA
     4.1  Standard Evaluation Procedure for Ecological
          Risk Assessment (EPA/OPP 1986)  	 C-42
     4.2  Computer-based Environmental Exposure and
          Risk Assessment Methodology for Hazardous
          Materials (Chemical Migration Risk Assessment;
          Onishi e_£ al. 1982, 1985)  	 C-47

5.  Methods/Assessments Developed Under RCRA
     5.1  Potential for Environmental Damage:
          Proximity of Mine Sites to Sensitive
          Environments (EPA/OSW 1987a)	 C-52
     5.2  Variances from the Secondary Containment
          Requirements of Hazardous Waste Tank  Systems:
          Risk-based Variance  (EPA/OSW  1987b)  	 C-54
     5.3  The RCRA Risk-Cost Analysis Model  (EPA/OSW 1984)	 C-57

                                     C-i

-------
                               LIST OF FIGURES

                                                                       Page

 Cl-1       NRDAM/CME Model  (DOI 1987a) 	  C- 3

 Cl-2       Food Web Model for CERCLA Type A Assessments  (DOI 1987a)  ..  C- 7

 C2-1       Generalized Flow Diagram for Assessment of
           Stratospheric Modification  (EPA/OAR 1987)  	  C-18

 C3-1       Schematic Diagram of EPA/OWRS  (1983) Approach to
           Risk Assessment  	 C-26

 C3-2       Biological Indices of Surface Water Quality
           in the Scioto River (Ohio EPA 1988) 	 C-35

 C3-3       Longitudinal Trends in Biological Indices of  Surface
           Water Quality in the Cuyahoga River (Ohio EPA 1988)  	 C-36

 C4-1       Schematic Diagram of the CMRA Methodology
           (Onishe et aj.. 1982, 1985)  	 C-48
                                                                           it
 C5-1       The Ecosystem Damage Function  (EPA/OSW 1984)  	 C-58

 C6-1       Example of a Fault Tree Analysis  (Barnthouse  ej£ al.  1986
           as used in EPA/OTS 1987) 	 C-64

 C7-1       Overlap in EEC and MATC Probability Distributions
           (Barnthouse e_£ al. 1986) 	 C-71

C7-2       Percent Response vs. Concentration
           (Barnthouse e£ al. 1986) 	 C-74

C7-3      The SWACOM Computer Model (Barnthouse et §1.  1986)  	 C-76

-------
                              TABLE OF CONTENTS
                                 (continued)
                                                                Page

6.  Methods/Assessments Developed Under TSCA
     6.1  Estimating "Concern Levels" for
          Concentrations of Chemical Substances
          in the Environment (EPA/OTS 1984) 	  C-61
     6.2  Ecological Risk Assessment in the Office of
          Toxic Substances, Problems and Progress
          (EPA/OTS 1987) 	  C-63

7.  Other Methods
     7.1  Users Manual for Ecological Risk Assessment
          (Barnthouse e_£ al. 1982,  1986) 	  C-67
     7.2  Regional Ecological Assessments:   Concepts,
          Procedures and Application (Ballou §_£ a\.  1981) 	  C-79
     7.3  Computer Simulation Models of Assessment of Toxic
          Substances (Eschenroeder e_t al,. 1980) 	  C-87
     7.4  Unfinished Business:  A Comparative Assessment
          of Environmental Problems.  Appendix III,
          Ecological Risk Work Group (EPA/OPPE 1987) 	  C-89
                                     C-ii

-------
                                LIST OF TABLES

                                                                       Page

C4-1      Wildlife and Aquatic Organism Data Requirements for
          the Standard Evaluation Procedure for Ecological Risk
          (EPA/OPP 1986) 	 C-44

C4-2      Selected Bibliography for the Chemical Migration
          Risk Assessment methodology  	 C-49

-------
Method Summaries                                                    Page  C-l


                                 INTRODUCTION

     In this appendix, we present a review of twenty ecological assessment
methodologies that have been developed for use by one or more Federal or  State
agencies.  This is not a comprehensive list of available ecological assessment
methodologies.  The methodologies included in our review are representative of
those used for three general types of applications:  setting environmental
criteria, setting priorities, and risk characterization for purposes of risk
management.

     We describe how the methodologies characterize ecological targets,
hazard, exposure, and risk.  The reviews are organized by the legal mandates
under which the methodologies were developed.  Methods developed under CERCLA
are presented first, followed by those developed under the Clean Air Act,
Clean Water Act, FIFRA, RCRA and TSCA.  Several other methodologies, not
developed under any specific legal mandate, also are included in this review.

-------
 CERCLA Type A Damage Assessment    DOI 1987a                  Page  C-2


               1.0  METHODS/ASSESSMENTS DEVELOPED UNDER CERCLA

 1.1  CERCLA TYPE A DAMAGE ASSESSMENT FOR COASTAL AND MARINE ENVIRONMENTS (DOI
     1987a)

 1.1.1  Introduction

     The Department of the Interior (DOI) has developed procedures for
 assessing damages to natural resources from a discharge of oil or a release of
 a hazardous substance compensable under either CERCLA or the Clean Water Act.
 Under CERCLA, states or the Federal government can assert claims for
 compensation for natural resource damage or injury following discharge of oil
 or hazardous substance release.  The Natural Resource Damage Assessment Model
 for Coastal and Marine Environments (NRDAM/CME) was developed for damage
 assessment following a single, relatively small (type A) release in coastal
 and marine environments.  The model is an interactive computer program that
 generates a measure of damages based on information regarding the nature,
 date, and location of a hazardous material release.  Minimal field
 observations are required.

     In the NRDAM/CME model, damages are defined as diminution in the use  •-
 value of natural resources resulting from injuries caused by a discharge or
 release.  Damages are equal to the difference in the i,n situ resource values
 pre- and post-incident.

     As Figure Cl-1 illustrates, the model comprises three major submodels and
 data bases.  The physical fate and transport submodel simulates the spread of
 contaminants from a discharge source over time and space.  The biological
 submodel estimates both direct and indirect effects on plants and animals.
 (Direct effects include contaminant-induced mortality; Indirect effects
 include lost productivity in higher trophic levels as a consequence of
mortality in lower trophic levels and reduced recruitment of larvae and
juveniles.)  The economic submodel estimates damages to commercial  and
 recreational fisheries.  Damages to public beaches, waterfowl, shorebirds,
 seabirds, and marine mammals are also estimated.  Biotic effects such as
 reduced growth rates, lost reproductive potential, increased susceptibility  to
other biotic stresses (e.g. disease, parasitism), or competitive relationships
between species are not addressed.

 1.1.2  Description of Method

     Receptor Characterization

     Receptor characterization under the NRDAM/CME model  is  limited to  coastal
and marine environments.  Within these environments, a  variety of  marine and
coastal bioraes are represented.  Coastal waters are  divided into ten regions

-------
CERCLA  Type A Damage Assessment    DOT  1987a
Page C-3
                                    FIGURE C14

                                 NRDAM/CMB MODEL
                              (Source:   DOI 1987a)
                                     USM
                               snu. rvpe. town ON. OATI.
                                HAllTAf CUSSiriCAriQN, MACM/
                                  HUNTINC/riSWHC

-------
  CERCLA, Type A Damage Assessment    DOI 1987a                  Page C-4


 or provinces which are further divided according to tidal position (i.e.,
 inter tidal/sub tidal) and bottom type (e.g., rock, sand, coral).  For each  of
 the resulting 91 ecosystem types, there are four categories of data: (1) adult
 biomass by species; (2) larval numbers by species category, (3) mortality  and
 growth parameters by species category; and (4) primary and secondary
 productivity values.

     Biological receptors are divided into categories: six fish species
 groups, three invertebrate groups, three bird groups, and one mammal group.
 The fish groups include anadromous, planktivorous ,  piscivorous, demersal,  and
 semi-demersal fish and top carnivores.  Three life stages are considered for
 fish and invertebrates:  egg/larval, juveniler- and adult.  Shorebirds,
 seabirds, waterfowl, and fur seals are represented by two life stages (adults
 and young).  Primary producers (e.g., phytoplankton, benthic micro- and
 macroalgae, and higher plants) and zoop lank ton are also considered.
 Seasonally dependent parameters considered in receptor characterization
 include temperature, adult and juvenile biomass by species group, abundance of
 birds and mammals (and their young), number of larvae, and primary
 productivity.

     Hazard Assessment

     The model includes toxicological data for 469 substances.  Hazard
 assessments for fish, invertebrates,' zooplankton, and phytoplankton are
 conducted using LC5Q and £€50 data.  A hazard value  for each species group  is
 derived by dividing the acute toxicity value by a safety factor of  100 to
 estimate a no-effect level.  This approach assumes that the same dose-response
 relationship holds for all hazardous substances.  Hazard values were derived
 in this manner for five organism groups:   (1) adult  and juvenile fish, (2)
 adult and juvenile benthic invertebrates,  (3) larvae of fish and benthic
 invertebrates, (4) zooplankton, and (5) phytoplankton and other primary
 producers.   For fish and invertebrates, the acute LC50 values  in the data base
were standardized to 25 degrees Centigrade and 96 hours of exposure. Sources
 of uncertainty surrounding the hazard values are not addressed.

     This hazard assessment methodology includes consideration of  the  effects
 of temperature and duration of exposure (if less than 4 days)  on the
 population response to a particular toxicant concentration.  For exposures
 lasting more than 4 days, the 4-day LC^Q is used.
     Toxicant -induced effects on primary productivity also are  considered  in
the hazard assessment.  Decreases in primary productivity are estimated  from
£€50 data using a log-normal toxicity model.  Decreases  in productivity  are
assumed to be independent of exposure duration.

     Potential hazards to other organisms are based  on more  limited data.
Birds and fur seals are assumed to be affected  only  by those substances  that
form surface slicks (petroleum products in most cases).  Based  on available
data, it is assumed that a fixed proportion of  birds and seals  that are  oiled
(according to the exposure submodel) will die (38% and 63%,  respectively).

-------
 CERCLA Type A Damage Assessment    DOI 1987a                 Page C-5


The uncertainty around these estimates, either as  representative means or
environmentally dependent variables,  is not addressed.

     Exposure Assessment

     The physical fates submodel estimates the distribution  of a contaminant
on the sea surface, in the water column (partitioned as  upper and  lower), and
in the sediments.  The user must enter specific information  concerning the
spill (e.g., type and amount of substance spilled, regional  province, and
bottom type).   The chemical data base of 469 compounds contains empirical or
estimated values for parameters used in the fate and transport model  (e.g.,
solubility, degradation rate in water and sediments, and viscosity).

     The model is designed to simulate the fate of pure  hazardous  substances,
crude oils, and petroleum products.  'Crude oil and petroleum products are
represented by four components: (1) low molecular weight aromatics (50/50
mixture of benzene and toluene); (2) medium molecular weight aromatics  (100-
160 g/mole); (3) an insoluble but volatile portion; and  (4)  a  residual
fraction which is neither soluble nor volatile.
                                                                          :t
     The time course of events is modeled using incremental  time  steps  scaled
with respect to the size of the spill.  Spatial variation is similarly  modeled
with a variable-sized horizontal grid.  The space in which the toxicant
concentration is estimated to be greater than the toxicity threshold is
divided into ten spatial volumes horizontally in each of three layers (upper
water column,  and lower water column,  if appropriate; and sediments).

     The concentration estimation methods consider several processes affecting
contaminant movement within and between compartments.  Contaminants on the
ocean surface spread under the influence of wind, currents,  temperature,
viscosity, evaporation, thickness of surface slick, and dissolution into the
water column.   Contaminants within the water column are transported
horizontally by current movement and dispersion.  Contaminants with a specific
gravity greater than seawater are modeled by a convective descent algorithm.
Contaminants that reach the seafloor enter the sediments via bioturbation
(e.g., bottom fish foraging).  The particulate and  interstitial concentrations
of the contaminant are modeled separately.  Dissolution of contaminants from
the sediment into the water column is  modeled.  Degradation is modeled  in both
the water column and sediments.  For substances spilled  in  the intertidal
area, the model calculates the area  impacted  and  a  removal  constant  which
accounts for dissolution, evaporation, and degradation.  All processes  are
deterministic except for vertical dispersion  which  is simulated as a random
walk.  Other sources of uncertainty  are not developed or propagated.

     Risk Characterization

     The biological effects submodel of  the  NRDAM/CME model combines the
quantitative exposure assessment model results with the biological data base
and indicates the numbers and biomass  of  organisms affected.  The submodel
estimates both short- and long-term  losses  to each of the biota  (receptor)
groups.  Short-term losses  include mortality that is a  direct  result of

-------
  CERCLA Type A Damage Assessment    001 1987a                  Page C-6


 exposure to toxicant concentrations above threshold.  Long-term losses include
 lost  recruitment  of larvae and juveniles into the breeding populations as well
 as  reduction in productivity at higher trophic levels as a result of lost
 primary and secondary production.  Other, more complicated biotic
 relationships, such as competitive release and density-dependent predator-prey
 population effects, are not included in this model because of the lack of a
 strong  empirical  and theoretical framework for such analyses.

      Single contaminants or petroleum products that are compartmentalized into
 four  subgroups can be modeled.  Exposure pathways include the water surface,
 water column, and sediments but not the transfer of toxicants up the food
 chain.   The environmental injury submodel is sufficiently simple to be
 generally applicable across coastal and marine environments.  It is
 sufficiently complex to incorporate several levels of effects.

      Short-term losses are calculated in the acute toxicity submodel.  This
 model estimates the fraction of each population (organism class) exposed to a
 given concentration that die based on the appropriate LC5Q value, temperature,
 and duration of exposure (if less than 4 days).  The biomass of each category
 of  organism is obtained from the biological data base.   As time progresses,
 more  organisms are exposed to the expanding contaminant plume.  In addition',
 fish  are  assumed  to swim into and out of the plume, thus exposing even more
 individuals.  Behavioral avoidance of the contaminant plumes is not
 considered.

      Long-term losses depend upon (1) lost primary and secondary production
 and (2)  lost recruitment of larvae and juveniles.  Reduced primary production
 is  estimated for  phytoplankton and macroalgae, when appropriate, using EC^Q
 information.  The reduction is passed on to two classes of secondary
 production: zooplankton and benthic invertebrates.  Direct losses of  secondary
 producers from toxic effects are also calculated, and the larger of  the  two
 types of  losses (indirect through reduced primary production and direct
 mortality) is used.  This assumes that the growth of zooplankton will  either
 be  food-limited or toxicant-limited, but not both.

      Lost primary and secondary productivity is translated  into  lost  yield  for
 each  animal species category via reduced food supply using a simple  food web
 model which is illustrated in Figure Cl-2.  The model is based on  simplifying
 assumptions which are applicable to all environments.
     1  Food chain efficiencies are  assumed to  be 20 percent.   The food web
model assumes that the share of each prey  item  that a predator consumes is
proportional to its biomass relative to  all other predators of that prey.
Larvae of fish and benthic invertebrates are assumed to feed entirely on
zooplankton and to be food-limited.

-------
 CERCLA Type A Damage  Assessment     DOI  1987a
                        Page C-7
                                  FIGURE Cl-2

                 FOOD WEB MODEL FOR CERCLA TYPE A ASSESSMENTS
                              (Source:   DOI  1987a)
                           Pp. PRIMARY

                           PRODUCTION
ANAOROMOUS
   FISH
    (I)
PISCIVOROUS
    FISH
    (3)
    TOP
 CARNIVORES
     (4)
                                                   BENTHOS
                                                   P..to. P.
                                                   (includes 7* 8)
DEMERSAL
  FISH
   (S)
          SEMI-
        DEMERSAL
          FISH
          (6)
PLANKTIVOflOUS
   FISH
    (2)
WATERFOWL
   AND
SHOREBIRbs
 (II, 13)

-------
  CERCLA Type A  Damage Assessment    DOI 1987a                  Page C-8


      Productivity and rates of transfer of energy from lower to upper trophic
 levels  are province-specific and vary by estuarine or marine environment,  by
 bottom  type, and by season.

      Reduction  of larval populations, either directly or indirectly, is
 translated into long-term catch losses using a fisheries model.  Density-
 dependent population dynamics are not incorporated.  Other adverse effects
 modeled include loss of waterfowl for hunting, losses of birds for
 recreational purposes (i.e., bird watching), lost fur seal production, and
 closed  beaches.

      Once measures of specific categories of injury have been estimated, the
 economic damages submodel places a dollar value on each type of loss.  Damages
 to  lower trophic biota, for which use or market values do not exist, are
 translated through the food web into reductions in species of monetary value.
 Region-specific valuations of commercial fish species are included.  The lost
 iB  situ value of each biological compartment is calculated separately for each
 year.

      Although sections of the model might be amenable to field validation,  it
 is  unlikely that the effort involved would be appropriate.  A more cost-  :
 effective approach would be through verification of the algorithms and
 sensitivity analyses.  The sensitivity analyses presented by the authors
 illustrated the following.  Economic damages increased linearly with the
 amount  of contaminant spilled.  Damages from the same size spill depended upon
 season  and province, with winter Arctic coastal spills three orders of
 magnitude less  costly than spring spills in the California estuarine
 environment.  In addition, the economic damages varied dramatically with the
 physical/chemical properties of the substance spilled.

 1.1.3   Operational Resource Requirements

      The NRDAM/CME model can be run on a personal computer, and can be
 obtained on a series of four diskettes along with the documentation from NTIS.
 These diskettes include all associated data bases for the ecological  regions
 and environments and complete data bases for 469 chemical compounds.   With  a
 minimum of information concerning an actual spill, the model is very  easy to
 run.  The high  cost and effort required to develop a model of  this  type has
 already been invested.  It is not known if the NRDAM/CME model will be updated
 in  future years.  The computer time required to analyze a single'spill depends
 in  large part on the size of the spill and can range from 10 minutes  for  small
 spills  (e.g., < 10 metric tons) to over an hour for large spills  (e.g'( >  500
 metric  tons).

 1.1.4  Summary

     The NRDAM/CME modeling approach is based entirely  on acute  toxicity  data
 for five general classes of organisms for each compound in  the chemical data
base.  From these data and a simple food-web model, population effects for
 several categories of animals and plants are determined.  When the empirical
data  indicate that an effect is highly variable  in the  real  world,  a "best"

-------
 CERCLA Type A Damage Assessment    DOI 1987a                  Page C-9


case estimate rather than a worst case estimate is selected as the input
value.  All output parameters are also represented by single values.  No
attempt is made to incorporate the uncertainty in either value measurements or
in the real world.  Considering the sizable data bases and the number of
estimations, extrapolations, and assumptions, providing an analytic
characterization of uncertainty from all sources would be difficult.

     The NRDAM/CME methodology is a relatively sophisticated approach to
ecological damage assessments for coastal and marine natural resources.  In
the context of providing a framework for Type A damage assessments  for CERCLA,
the final endpoints of concern are translated into economic losses.
Nonetheless, a wide diversity of endpoints are considered, analyzed, and
presented along with the final monetary evaluations.

-------
 CERCLA Type B Damage Assessment      DOI 1987b                Page C-10

 1.2  TYPE B HAIOBAL RESODRCK DAMAGE ASSESSMENT (DOI 1987b)

 1.2.1  Introduction

      The  Department of  the Interior (DOI) has developed procedures for
 measuring damages  to natural resources resulting from a discharge of oil or a
 release of a hazardous  substance compensable under either CERCLA or the Clean
 Water Act.   The Type B  damage assessment procedure is intended to provide
 guidance  for conducting site-specific assessments based on data collected in
 the field.   The procedure is different from the other assessment methodologies
 included  in our review  because it focuses on field measurements of impacts
 that have already  occurred, rather than the probability that impacts will
 occur.  Therefore,  hazard and exposure assessments, typical components of
 ecological risk assessments, are not conducted, nor is there a risk
 model/method to combine hazard and exposure information.  Nevertheless, the
 damage assessment  procedures provide some conceptual approaches that may be
 potentially applicable  to ecological risk assessment.

      Type B natural resource damage assessments involve three major steps:
 establishing that  an injury has occurred and that the injury resulted from a
 discharge or release; quantifying the effects of the discharge or release; and
 determining the damage.  Injury is defined as a measurable adverse change in
 the  chemical or physical quality or viability of a natural resource.  Damage
 is  defined as  the  amount of money sought by the Federal or state agency acting
 as  trustee  for the  natural resource to compensate for the loss.  Natural
 resources include  surface water, ground water, geological resources (soil,
 rocks,  and  minerals) and biological resources.  Injury is defined uniquely for
 each natural resource and is documented following collection of field or
 laboratory  data and statistical analysis.

 1.2.2   Description  of Method

      Receptor  Characterization

      Potential receptors include representative components of the entire
biosphere;  both the biotic (aquatic and terrestrial) and abiotic  components
 (air,  land,  water)  of ecosystems are considered.  Assessments of biological
 injury  are  conducted at the population level.

      Hazard Assessment

     As discussed previously, the damage assessment does not have a "true"
hazard  assessment procedure.  However, the definition of injury  for each
natural resource may be useful in characterizing hazard assessment endpoints
for  ecological risk assessments.

      Injury  to surface  water and ground water occurs when  the water
concentrations of substances are in excess of Federal or State  drinking water
standards or water  quality criteria, or are sufficiently elevated to  cause
damage  to other natural resources.  Also, an injury has occurred if  the
substance's  concentration in bed, bank, or shoreline sediments  is sufficient

-------
CERCLA Type B Damage Assessment      DOI 1987b                Page C-ll

to cause the sediment to exhibit characteristics of hazardous  waste  (as
defined under RCRA).

     Injury to air occurs if the concentrations of emissions are  in  excess of
standards for hazardous air pollutants established by Federal  or  State
regulations or if the concentrations are sufficient to cause injury  to other
natural resources.

     Injury to geologic resources occurs if the concentration  of  a substance
in the geologic resource is sufficient to cause damage to other natural
resources or is sufficient for the materials in the geologic resource  to
exhibit the characteristics of hazardous wastes (as defined under RCRA).  Also
an injury has occurred if the concentration of a substance is  sufficient  to
alter soil pH, salinity, or water-holding capacity beyond prescribed levels,
to impede soil microbial respiration and soil carbon mineralization, or  to
cause a toxic response in plant or soil invertebrates.

     A biological resource is injured if it or its offspring have undergone  at
least one of the following changes in viability:  death,  disease, behavioral
abnormalities, cancer, genetic mutations, physiological malfunctions,  or
physical deformations.                                                   '• •

     The method for determining injury.is limited by the capability of the
method to demonstrate a measurable biological response.  According to the
criteria established by DOI, only certain procedures within the six injury
categories are sufficient to demonstrate an injury to a biological  resource.
These are discussed briefly below by injury type.  In all cases,  measured
responses in injured populations must be statistically different from control
populations.

     Death.  Death can be measured in both fish and wildlife.   Three
acceptable measures of death in fish are fish kills, in situ bioassays using
cultured or indigenous fish, and laboratory tests of acute or subchronic
toxicity.  The only acceptable approach to document oil or hazardous substance
related death in wildlife is a brain cholinesterase inhibition of at least 50%
in field populations compared with control populations.  Lesser  inhibition,
but in excess of 20%, can be considered contributory  to death provided that
such inhibition is statistically separable from controls.
     Disease.  Acceptable approaches for documenting disease  injury  in  fish
are limited to fin erosion and lesions on fish tissue.  Acceptable approaches
for documenting disease in wildlife populations are not available.

     Behavioral abnormalities.  Procedures adequate to document  behavioral
changes in fish are limited to laboratory studies  of behavioral  avoidance  in
species representative of site conditions and observations  of clinical
behavioral signs of toxicity.  For wildlife, injury has occurred if  there  is
statistically significant increase in observations of clinical behavioral
abnormalities in field populations versus controls, or  if two or more
specimens display behavioral abnormalities while none do  in the  control
populations.

-------
 CERCLA Type B Damage Assessment      DOI 1987b                Page C-12

      Cancer.  Statistically significant increases of liver or skin neoplasia
 are  sufficient  to document cancer injury in fish.  Injury determination  in
 fish can be documented via field sampling of natural populations or bioassays
 using water from the potentially affected area and standard laboratory assay
 species.  No acceptable procedures have been identified to document cancer
 injury in wildlife populations.

      Physiological malfunctions.  Altered physiologic parameters accepted as
 adequate documentation of physiologic malfunctions are reduced reproduction in
 fish;  and egg shell thinning, reduced reproduction, reduction in brain ChE,
 and  decreased delta amino levulinic acid dehydratase (delta ALAD) in birds and
 mammals.

      Physical deformations.  Injury from physical deformations can be
 documented in wildlife if there is an increased  incidence of external
 malformations,  skeletal malformations', internal whole organ and soft tissue
 malformations,  or histopathological effects between suspect polluted locations
 and  control areas.  No such measures were identified as adequate for
 documenting physical deformation ini	 in fish.

      Exposure Assessment

      An exposure assessment is not included in the damage assessment.
 Although the regulations stipulate that exposure pathways must be delineated,
 specific procedures to document a pathway are not provided.

      Risk Characterization

      This method does not include a risk model/method.  However, procedures to
 quantify damages by establishing a dollar value  for the injury have been
 outlined.  Quantification  of injury to biological resources can be based  on
 changes in populations (often quantified by numerical counts of injured
 individuals) or on changes in ecosystems or habitats.  The Fish and Wildlife
 Service has proposed the use of habitat evaluation procedures  (HEP) to
 quantify changes in fish and wildlife habitats.  HEP is an accounting
 procedure for tracking an integrated measure of  habitat quality and surface
 area  of habitat.  The integrated measure is called a Habitat Unit  (HU).   The
 number of HUs is defined as the product of the Habitat Suitability  Index  (HSI)
 and  the area of available habitat.  HSIs and HUs are calculated  for certain
 "evaluation species".  The procedure can be used to quantify reductions  in
habitat quality between a polluted area and a control area.

 1.2.3  Operational Resource Requirements

     The damage assessment procedure is a relatively labor-  and cost-intensive
approach because field sampling and/or laboratory  testing and  economic
analyses are required.  Theoretically, selected  aspects  of this  approach could
be modified and applied to ecological risk assessments.   However,  the
operational resource requirements of a modified  approach cannot be evaluated
at this time.

-------
CERCLA Type B Damage Assessment      DOI 198 7b                Page C-13


1.2.4
     The 001 Type B damage assessment regulations provide procedures for
injury determination.  These procedures, however, are not ecological risk
assessment procedures, and are therefore limited in their applicability for
risk assessment.  However, compilation of data from Type B damage assessments
could provide valuable case-study data for risk assessment.  In addition, the
method does offer some unique approaches to define ecological injury.  For
example, under these procedures receptors include both biotic and abiotic
ecosystem components.  Many ecological risk assessment methodologies consider
only how changes in the abiotic component can impact the biotic components of
the ecosystem.  The approach offered by DOI is unique in that abiotic
ecosystem components are recognized as important resources irrespective of the
associated biotic components.

     The DOI damage assessment approach also considers the interactions
between the abiotic and biotic components.  Consideration of interactions
between system components can loosely be considered an ecosystem approach.
Although other approaches do consider ecosystem effects, implementation of the
approach is not common.                                                    •'•

-------
 Ozone Staff Paper                  EPA/OAR 1986               Page C-14


           2.0 METHODS/ASSESSMENTS DEVELOPED UNDER THE CLEAN AIR ACT

 2.1 REVIE0 OF THE NATIONAL AMBIENT AIR QUALITY STANDARDS FOR OZONE:
     STAFF PAPER (EPA/OAR 1986)

 2.1.1  Introduction

      The  Office  of Air Quality Planning and Standards (OAQPS) reviewed the
 secondary National Ambient Air Quality Standard (NAAQS) for ozone in their
 staff paper dated March 1986.  The secondary standard is intended to be
 protective of both symptomatic health effects in humans and human welfare,
 including impacts on vegetation and natural ecosystems.  Of particular concern
 are  the adverse  effects of ozone on plants.  OAQPS identified short-term and
 long-term ambient ozone concentrations associated with low-effect levels for
 plants, and then evaluated whether certain criteria (e.g.,  the primary NAAQS
 for  human health effects) would adequately protect agricultural plants and
 forests.

      The  approach used by OAQPS was not developed as a generic risk assessment
 methodology.  We discuss it here because it is an example of the use of
 ecological  risk  assessment, and can in fact be used for other chemicals.   '

 2.1.2  Description of Method

      Receptor Characterization

      The  assessment focused on terrestrial plants, particularly crops and
 forest species,  although aquatic systems were discussed briefly.  Although
 OAQPS  summarized the effects of ozone at the individual, population, and
 community  levels, the exposure and risk assessments emphasized effects
 occurring  at  the population level.

     Hazard Assessment

      In the hazard assessment, concentrations of ozone that are toxic to
 plants were identified.  Both qualitative and quantitative assessments were
 conducted.  The  qualitative assessment included descriptions of toxic
 endpoints and toxic concentrations at the ecosystem level  (e.g.,  effects  on
 aquatic systems bordering damaged forests), as well as at  the population  and
 individual levels (e.g., decreased photosynthesis).  Response modifying
 factors such as water stress, nutrient deficiency, and pest and disease
 interactions also were discussed.

     In the quantitative assessment, the hazard evaluation was  limited  to
population-level effects on agricultural crops because of  data  limitations.
Hazard was expressed in terms of air concentrations associated with phytotoxic
 responses.  Hazard was evaluated for two concentration averaging  periods:   (1)
a short-term peak expressed as a number of occurrences above a  given level
 (multiple exceedances) and (2) a long-term average (expressed over a growing
season of three months).  For the short terra assessment, a peak criterion of
0.08 ppra was selected because concentrations of this level or higher are

-------
Ozone Staff Paper                  EPA/OAR  1986               Page C-15

definitely injurious to sensitive plant  species when they are exposed for even
short periods of time,  usually less than one hour  (Garner 1988).  White pine
has been used as an indicator species,  injury being determined by visible
foliar damage and growth measured by tree ring number and width.  The long-
term average criterion was derived primarily from  yield-reduction experiments
on crops.  The protectiveness of the long-term standard  to  forest species was
addressed qualitatively.  Damage as used in the assessment  is a chronic
endpoint because it occurs over a lifetime  (3-month growing season for crops,
or tens of years for trees).

     In the long-term hazard assessment, a  10% reduction in yield was used  as
the effect level of concern.   The 10% level was chosen because  it can be
detected with some degree of confidence and is generally considered  a
significant effect.  Long-term ozone concentrations associated  with  a  10%
reduction in yield (0.04 to 0.05 ppm. ozone) were  determined from dose-response
curves developed from experiments conducted as part of  the  National  Crop Loss
Assessment Network (NCLAN).  This range of  concentrations was  then compared
with data from greenhouse and controlled environment  studies and with  ambient
air-exposure studies using crop species. The  final range of concentrations
associated with a 10% reduction in yield (0.04 to 0.06  ppm  ozone) was
presented as a 7-hour 3-month average.    The  7-hour component of  this  average
was chosen because it may correspond to the period of greatest  plant
sensitivity to ozone (0900-1600 hr).  The three-month component might  not  be
applicable to deciduous forests, and is not applicable  to coniferous forests.
Moreover, repeated, short-term, high-level concentrations can be more injurious
than continuous low-level ozone concentrations that represent the same
"average" concentration (Garner 1988).

     Exposure Assessment

     Data from EPA's SAROAD  (Storage and Retrieval of Aerometric Data) data-
base system were used to summarize  current ozone concentrations in the United
States and to predict future concentrations.   Current concentrations of ozone
were compared to the peak concentration of 0.08 ppm proposed in the hazard
assessment as a short-term criterion based on phytotoxicity.  Data gathered
from 1982 to 1984 indicated  that average hourly ozone concentrations in
agricultural areas exceeded  0.08 ppm on  the average 119 times each year.   In
remote areas, average hourly ozone  concentrations exceeded 0.08 ppm on average
37 times each year.  A  series of longer-terra averages were also presented.

     The SAROAD ozone concentration data were also used to predict  ozone
concentrations that would  result if the human-health-based peak criterion  of
0.12 ppm were attained.  Assuming  peak  ozone concentrations of 0.12 ppm,  the
percentage of days with hourly  maxima exceeding 0.08 ppm were  calculated,  and
the 7-hour, 3-month average  concentration  was estimated on the basis  of
significant (but weak)  correlations between the  second-highest daily  maximum
concentration, long-term concentrations and short-term  peaks.  Assuming a
second-highest daily maximum of 0.12 ppm (corresponding to the human  health
criteria), there is a 10%  chance  that  32%  or more of the days  in a  3-month
growing seasons will exceed  a 7-hour,  3-month average  of 0.08  ppm.   A 7-hour,
3-month average concentration of 0.052  ppm was predicted with  an upper bound
(90%) estimate of  0.063 ppm.

-------
 Ozone Staff Paper                  EPA/OAR 1986               Page C-16


      Risk Characterization

      Risk to terrestrial plants was evaluated qualitatively and focused on the
 risk associated with  the human health-based peak criterion of 0.12 ppm.  Both
 the  daylight-hours seasonal mean and 90th percentile concentrations calculated
 based on  attainment of  the 0.12 ppm peak level were compared with the range of
 concentrations associated with effects.  The degree of short-term risk to
 terrestrial plants was  addressed by evaluating the percentage of days expected
 to exceed 0.08 ppm if the 0.12 ppm criterion were attained.  Finally, the
 large uncertainty in  the correlation between short-term and long-term ozone
 concentrations (coefficients of determination ranged from 0.3 to 0.4) was used
 to support the proposal of a long-term ozone standard in addition to the
 short-term standard.

      The  assessment has been partially calibrated since the hazard assessment
 was  based in part on  effects using ambient ozone levels and on field studies.
 Quantitative validation could be conducted using charcoal filtered ambient air
 studies.

 2.1.3   Operational Resource Requirements

      Data on the toxic effects of ozone were available for many major crop
 species and a few natural communities.   The experimentation required to
 develop exposure-response curves for plant species was extensive and
 expensive,  as was the data collection done to develop the statistics on
 ambient ozone concentrations.  Therefore, application of this type of approach
 for  ecological assessments of other chemicals is likely to be costly and  labor
 intensive.   Once these data have been developed, however, the cost and level
 of effort  needed to estimate risk is low, and the assessment is
 straightforward.

 2.1.4  Summary

     The use  of an extensive monitoring effort and exposure-response
characterization is a powerful and useful combination.  Limitations  of this
approach  include the extrapolation from controlled experiments  to plants
growing in the field, and the emphasis on yield reduction as the  toxic
endpoint of  concern.   Strengths of this procedure are that it uses exposure-
response modeling and considers temporal characteristics of the receptor.
Also, community and ecosystem level effects as well as response modifying
factors were qualitatively assessed.

-------
 Stratospheric Modification          EPA/OAR 1987               Page C-17

 2.2  AH ASSESSMENT OF THE RISK OF STRATOSPHERIC MODIFICATION (EPA/OAR 1987)

 2.2.1  Introduction

      The purpose of this probabilistic risk assessment was to aid the EPA
 Administrator in determining the need for additional controls on the releases
 of  substances that may affect the stratosphere.  The report assessed the
 likelihood  that:

      (1)  different human activities would result in climate modification or
          in an alteration of the stratosphere's ability to filter ultraviolet
          radiation,  and

      (2)  changes in  ultraviolet radiation (UV-B) or climate due to
          modifications in column ozone or stratospheric water vapor would
          have detrimental effects on -public health or welfare.

      This review addresses only the ecological components of the overall
 assessment.  Two physical effects of stratospheric modification were included
 in  the  ecological assessment:  increased UV-B, and climate change/sea level
 rise.   The  general approach for assessing ecological risks from the two
 physical effects was  similar.  A deterministic model was used to estimate  ••'
 emissions and ozone depletion.  Additional models were used to estimate the
 increase in UV-B and  temperature attributable to the emissions.  Exposure-
 response data or qualitative information was then used to estimate ecological
 effects.  A generalized flow diagram is shown in Figure C2-1.

 2.2.2   Description of Method

     Receptor Characterization

     Increased UV-Q.  Both aquatic and terrestrial receptors were considered
under this  approach.  Although community -level endpoints were considered
qualitatively,  quantitative assessments were limited to the population  level,
primarily because of  the paucity of exposure -response data for higher level
effects.  Single species were chosen as receptors for the quantitative
assessments:  soybeans in terrestrial systems and anchovies in aquatic
systems.  No attempt was made to generalize from these species to other
species or  levels of organization.  Temporal characteristics of northern
anchovies were discussed and incorporated into estimates of risk.
             Change/Sea Level Rise.  The climate change assessment  primarily
addressed natural plant communities.  Coastal wetlands, particularly those  in
Louisiana, Florida, Delaware, New Jersey, and Maryland, were  identified as
"receptors" of concern for potential effects of sea  level  rise.

-------
   Stratospheric Modification
                    EPA/OAR 1987


                 FIGURE C2-1
Page C-18
                    GENERALIZED FLOW DIAGRAM FOR ASSESSMENT  OF

                            STRATOSPHERIC MODIFICATION

                             (Source:   EPA/OAR 1987)
Year
Loop
                     Input
                     Files
                  Production
                  Scenarios
                    Module
                        T
                    Policy
                  Alternatives
                    Module
Emissions
 Module
                        r
                        I	
                        I	
                                    I	»
                 Atmospheric
                   Science
                   Module
                        I	
                    Effects
                    Module
                        I	
Summary
File
^_^^


Report
Writer
Program


Output
Re
^_^x^

-------
 Stratospheric Modification          EPA/OAR 1987               Page C-19

     Hazard Assessment

     Increased UV-B.  For the qualitative assessment of hazard to aquatic
 organisms, effects to a wide variety of species, including fish larvae and
 juveniles, shrimp larvae, crab larvae, copepods, and aquatic plants, were
 discussed; however, effects on planktonic organisms were emphasized.   Most of
 the quantitative data available addressed anchovy mortality, but sublethal
 effects such as reduction in fecundity were also discussed.  Temporal
 attributes of the organisms, particularly diel vertical movement of zoo-  and
 icthyoplankton, were recognized as important uncertainties.  Tolerance and
 avoidance mechanisms were also discussed.  The most complete exposure-response
 data were available from laboratory tank experiments with anchovy larvae.
 These data were reinterpreted to include scenarios for vertical movement
 during the day by the larvae.

     The assessment of effects on terrestrial organisms was limited to effects
 on plants.  Little information was available for natural vegetation.  Toxicity
 modifying factors such as mineral deficiency and water stress were discussed.
 Although effects on yield were emphasized, effects on yield quality and
 community-level effects, such as changes in plant competition and increases in
 disease and pests, were also discussed.  The most complete exposure-response
 data were available for soybeans.  The extrapolation from controlled
 experiments to effects in the field was recognized as a particularly
 significant source of uncertainty, but was not  factored into the exposure-
 response quantification.

     C14.pa.pfii, Change/Sea Leve], Rise.  The effects of climate change  on plants
 were addressed using several methods.  Paleovegetational records were analyzed
 to identify a possible historical analog to potential climate change, and
 present-day, vegetation-climate classifications of plant communities were
 discussed.   In another approach, pollen abundances were correlated through-
 regression techniques to climatic variables, such as temperature and  rainfall.
 Response surfaces were then constructed.  Such  empirical response  surfaces  are
 available for many North American species.  In  general, the rate of climate
 change was identified as an uncertainty that has not yet been adequately
 addressed.

     Another approach, still in the early stages of development, was  the  use
 of vegetation models that represent forest dynamics by  a series of stochastic
 and deterministic equations.  Exposure-response relationships based on
 empirical data or process-oriented theory were  used to  model  the response of
 individual plant taxa.  Currently these models  are  limited because the  rate of
 climate change has not yet been considered, and because only  North American
communities have been modeled.

     The discussion of effects of sea-level rise on wetlands  emphasized
effects on coastal wetlands, including inundation,  salt-water intrusion,
decline in peat formation, and shoreline erosion.   Modifying factors, such as
 the degree of protection of shore-front property were  also discussed.

-------
Stratospheric Modification          EPA/OAR 1987                Page C-20

     Exposure Assessment

     The exposure assessment component of the model  is  shown in the first  four
modules of Figure C2-1 and, for the purposes of this summary,  also in part of
the fifth module.  Based on assumptions regarding production scenarios  and
policy alternatives, the emissions of stratospheric  modifying gases were
predicted.  The atmospheric module then estimated the amount of ozone
depletion associated with the emissions.   The effects module estimated  lateral
ozone depletion from the one-dimensional model and estimated the amount of UV-
B increase associated with the predicted depletion.   The National Academy  of
Science mid-range estimate of climate sensitivity to a doubling of C02  was
used to predict temperature change.  Broad changes in sea level rise by the
year 2100 were estimated for a range of warming scenarios.

     Uncertainty in the exposure assessment was quantified in several ways in
the different modules.   Uncertainty in estimates of the production  of
stratospheric ozone-depleting gases was addressed by the use of five  different
sensitivity cases, using varying assumptions regarding future populations  and
economic growth.  Different policy alternatives for controls on future  use
were specified.  The output of the atmospheric module was presented  as  a  range
based on a given range of uncertainty for estimates of future population  arid
economic growth.

     Other uncertainties could not be quantitatively incorporated into  the
modules.  For example, possible changes in technology were not included in the
emissions module.  The atmospheric module does not have the resolution to
predict regional effects.  Finally, factors that are as yet undefined or
poorly understood, such as biogeochemical cycles, could not be incorporated.

     Risk Characterization

     The model is deterministic in that a unique output or result is produced
by a specified input; there are no stochastic elements within  the model.   The
exposure assessment component of the model estimated future emissions of
stratospheric modifying chemicals.  The resulting depletion of ozone,  increase
in UV-B, rise in equilibrium temperature, and rise  in sea level  were
quantitatively modeled.  The effects of increased UV-B on soybean yield and
northern anchovy mortality rate were presented as ranges derived from  case
studies and on-going research.   Changes in  forest  community  structure were
assessed qualitatively based on a doubled CC*2 scenario, but  the  rate of change
was not considered.  A range of percent coastal wetland  loss  in U.S. was
estimated based on an analysis of topographic maps  and wetlands  inventories,
and on a consideration of possible protection of shorefront property.

     The model has been partially validated; current measurements of ozone
were compared with model predictions.  Because of the  global nature of the
problem, it will be very difficult to  validate the  predicted effects.
However, the changes in plant communities predicted to  occur with climate
change could be validated/calibrated using  historical  (paleobotanical) data.

-------
Stratospheric Modification          EPA/OAR 1987               Page C-21
2.2.3  Operational Resource Requirements

     The level of effort and expertise needed to develop the model was very
high.  As it exists now, a moderate level of effort, expertise, and a computer
would be needed to use the model to adequately address different regulatory
and gas production scenarios.

2.2.4  Summary

     There are many limitations and uncertainties in the models, exposure -
response curves, and effects data used to predict the effects of stratospheric
modification.  Nevertheless, the model provides a consistent framework by
which different future scenarios and policy options can be evaluated.  In
addition, the approach is flexible enough so that changes or additional
modules can be incorporated as the state of knowledge improves.

-------
 AWQC                         EPA/OWRS 1986                   Page C-22


         3.0  METHODS/ASSESSMENTS DEVELOPED UNDER THE  CLEAN WATER ACT

 3.1  GUIDELINES FOR DERIVING NUMERICAL NATIONAL WATER QUALITY CRITERIA FOR
      THE PROTECTION OF AQUATIC ORGANISMS AND THEIR USES (EPA/OWRS 1986)

 3.1.1  Introduction

      The Environmental Research Laboratories at Narragansett, Duluth,  and
 Corvallis developed guidelines for the Office of Water Regulations and
 Standards (OWRS) for establishing limits to chemical concentrations in surface
 water that are protective of aquatic organisms, human health, and some
 recreational activities.  The guidelines address the development of ambient
 water quality criteria (AWQC) for two measurement averaging periods:  1 hour
 and 4 days.  These two criteria are known as the acute and chronic criteria,
 respectively.

 3.1.2   Description of Method

      Receptor Characterization

      Aquatic organisms are the primary focus of this method.  The methodology
 is  designed to establish chemical concentration levels which, if not exceeded,
 should be protective of 95% of the species  in the aquatic community.  The
 method is designed for generic receptors, but can be modified to cover site-
 specific or locally-important species (e.g., commercially important species).
 Toxicity data from tests on the most sensitive life stage are recommended, but
 are  not essential.  Niche characteristics are not directly considered  in  the
 method unless field data for bioaccumulation of the chemical are available.
 The  method is more fully developed for animals than for plants primarily
 because the test methodology is more refined for animal species.

     Hazard Assessment

     The methodology is designed to establish chemical concentrations  which,
 if not  exceeded more than once in three years, will be protective of 95%  of
 aquatic species.  The necessary data include acute and chronic toxicity data
 for  animals and plants (including algae), bioconcentration or bioaccumulation
 factors, and either FDA tissue action levels or chronic wildlife  feeding/field
 study  results.  The most rigorously defined criterion is the 1-hr maximum
 concentration.  Data requirements for calculation of  this criterion include
 toxicity data for animal species from a specified taxonomic  range of orders
 and  families.  The maximum continuous concentration (4-day)  value  is taken as
 the  lowest of either an animal chronic value, a plant toxicity value,  or  a
 tissue  residue value.

      The chronic toxicity value for aquatic animals  can be  calculated from
chronic bioassay results in the same manner as the 1-hour maximum
concentration, that is, by using toxicity  data for animal species from a
specified taxonomic range of orders and families.  An alternative method is Co
use a chemical-specific acute:chronic toxicity ratio  applied to  the acute
value derived above.   The ratio method requires  considerably fewer  daca Chan

-------
AWQC                          EPA/OWRS 1986                   Page C-23

the chronic bioassay data set requirements.   A toxicity value for plants is
simply taken as the lowest reported toxic concentration for a plant or algal
species.  A specific plant toxicity endpoint is not  specified.  A tissue
residue value is calculated from data on either FDA  action levels or chronic
wildlife feeding or field studies and bioconcentration or bioaccumulation
factors.

     Guidance is provided on appropriate test methods, test species, and life
stages to be included in the data sets.  Also, a regression method  is  included
for calculation of acute and chronic toxicity levels when the toxicity of  the
chemical is affected by background water quality (e.g., water hardness).   Salt
and fresh water criteria are calculated separately.   If a criterion is above a
documented toxic threshold for a commercially or recreationally important
species, the criterion can be replaced with the lower toxic level.   The method
is designed to calculate a criterion .that corresponds to a value  for a species
representative of the lowest fifth p'ercentile of species ranked according  to
sensitivity, and so is designed to be protective of  95% of  the  tested  species.
Guidelines are set for the development of single chemical criteria  only;
mixtures are not addressed.

     Exposure Assessment

     Exposure to aquatic organisms is assumed to occur only through water,
although exposure to predators through the food chain is  assessed by the
residue value.  The estimation or measurement of exposure  in the environment
is not a component of criteria development.

     Risk Characterization

     An assessment of the potential for adverse ecological effects can be
conducted by comparing the criteria generated by the above method to
concentrations of chemicals measured or estimated in the environment,  as
described in Sections 5.2 and 7.1.1.  Criteria are not calculated for
chemicals with insufficient taxonomic breadth  in the available data.  That the
method is protective of 95 percent of aquatic  species and that this level of
protection prevents adverse ecosystem-level  effects could be validated, but
only by extensive field monitoring projects.

3.1.3  Operational Resource Requirements

     A computer program that can be run  on  a personal computer is  available
for performing the calculations.  Large  toxicity data bases exist  for plant
and animal species which can be used by  this method.  However, the range  of
required species which have been tested  with each chemical restricts  the
number of chemicals for which an acute and  chronic  criterion can be
calculated.  The level of  effort is  low,  particularly if the computer program
is available.  However, validation  of  literature reports requires  a high  level
of expertise.

-------
AWQC                          EPA/OWRS 1986                   Page C-24


3.1.4  gimrpju-y

     The guidelines were developed to calculate water quality criteria that
will be protective of populations of most aquatic organisms.  The guidelines
are not concerned with what effects, if any, will occur in the ecosystem if
concentrations reach or exceed the benchmarks.  Criteria are developed for
both acute and chronic exposure scenarios.  The acute criterion is a
prediction of a concentration threshold above which acute toxicity to some
species might occur.  It is derived primarily from laboratory acute toxicity
data.  The chronic benchmark can be derived from one of three data sets.  No
weighting is given to the quality or quantity of data within each data set.
The lowest of the three chronic values (i.e., animal, plant, and tissue
residue values) is chosen arbitrarily, even though the calculation schemes are
different.  The calculation schemes themselves are straightforward.  However,
validation of input data requires a high level of expertise in the area of
aquatic toxicology.

     Strengths of the approach are its wide applicability and rigor in
requiring a minimal set of data to calculate a criterion.  Limitations are
that community or ecosystem effects are not directly assessed and that
guidelines have not yet been established for chemical mixtures.

-------
  Approach to Exposure and Risk      EPA/OWRS   1983             Page C-25

 3.2  AN APPROACH TO ASSESSING EXPOSURE TO AND  RISK OF ENVIRONMENTAL
      POLLUTANTS (EPA/OWRS 1983)

 3.2.1  Introduction

      A.D.  Little,  Inc.  prepared  this document  for the Office of Water
 Regulations and Standards (OWRS)  to  provide guidelines  for conducting risk
 assessments for waterborne pollutants and to identify priorities  for further
 development.   Part of the guidelines presented are for  assessment of risks to
 non-human biota.   A schematic diagram of  the proposed approach to risk
 assessment is shown in Figure C3-1.   The  approach is qualitative.  The  result
 of the assessment  is a listing or summary of species, locations,  exposures,
 and effects levels,  indicating the combinations most likely to result in high
 risks.

 3.2.2  Description of Method

      Receptor Characterization

      Emphasis is placed on aquatic organisms,  although  the procedure is
 intended to be used to  assess risks  to any organisms coming in contact  with
 water (e.g.,  waterfowl).   The guidelines  suggest that the assessor identify'"
 specific communities or species exposed or potentially  exposed to the
 pollutant.  Representative sensitive species should be  identified and their
 ranges  delineated.   In  addition,  behavior patterns (i.e., migration, age
 structure)  that might increase or decrease the potential for exposure should
 be  described.

      Hazard Assessment

      The proposed  hazard assessment  is based on a literature review.  Because
 the procedures  are intended to be used for the priority pollutants,  it  is
 assumed that  Ambient Water Quality Criteria will be available.  The  result of
 the hazard  assessment is  a tabulation of  effects by species affected (e.g.,
 fish, aquatic  invertebrates)  and  by  type  of effect (e.g., lethal  and
 sublethal).   No methods for extrapolation between species or time frames are
 suggested.  When available,  the relationship between toxicity modifying
 factors  and effects  should be included in the  summary.

      Exposure Assessment

      Potential  for exposure is estimated  using either environmental  fate and
 transport models or  field monitoring.   Exposure analysis components  include
 identification  of  the concentration  of the chemical, the areal extent of
 contamination,  and temporal variation in  levels of contamination.

     Risk Characterization

      It is assumed that incomplete data will necessitate qualitative
environmental assessments  the majority of the  time.  An initial  assessment is
made  to determine  whether  the chemical is likely to have  (1)  no  effect  on

-------
Approach to Exposure  and  Risk
          EPA/OWRS   1983
                                                                                    Page C-26
                                           FIGURE  C3-1

                          SCHEMATIC  DIAGRAM  OF  EPA/OWRS  (1983)
                                APPROACH  TO  RISK ASSESSMENT
          I KrH.I'S ANALYSIS
                                                                            KXri>S11RK ANALYSIS
                            Input I rum
                            Htm i tor inn
                                                             Itipnc  Krm
                                                             F.ni- .iml
                                                             ('.it liw.iv^
                                                             An.i \ ys i ^
Itlvnt 1 1 1 1 .it li MI
C inns  or  I .it I'ntt
l.iH-.it ions When-
Aqu.it i<  DrRjni-i
l.ikclv l<> (lei nr
                                                     f I n* .1-
                                                     it's «»(
                                                     Risk In
                                                     s is
                                                             I npuiH  KriM* ]
                                                             M.itiTi.il-1    -H
                                                             H.il.im-t*    j
                                        lUrnc i f ir.it inn
                                        of ArcoH Wlu-ri-
                                        Tonccnir.it ions
                                        .ire  l.xpet te»l »r
                                        Hf.isurt'J to he
                                        Miph
                                        Idrnt i f it .it i on
                                        ot  r.ii tors
                                        Moil i f v l ny Av.i i I
                                        .ihil ily nf
                                        .1  t'i»l 1 ni .mt  it
                                        .»  Mi-.isiiriMl
                                        dim* 4-ttt r.it i«»n

-------
 Approach to Exposure and Risk      EPA/OWRS  1983             Page C-27

aquatic organisms; (2) some effects on certain sensitive species;  (3) effects
on most species; or (4) effects on all species.  Exposure and hazard
information is then examined to refine the rough analysis.  Possible
refinements include comparing time-dependent patterns of contamination levels
(e.g., persistence, seasonal fluctuations) with species activity patterns and
considering toxicity modifying factors such as hardness.  Expected results can
be validated with information on fish kills or field sampling programs.  The
goal of the assessment is to establish "key intersections" between exposure
and effects data with regard to specific species and geographic  locations.
The product of the analysis is a listing or summary of species,  locations,
exposures, and effects levels, with an indication of the combinations most
likely to result in high risks.

3.2.3  Operational Resource Requirements

     The approaches proposed in this.document can be made more sophisticated
or simple, depending on needs and resources.  If collection of field  data is
necessary, resource needs will be high.  Although the approach is simple and
qualitative,  it requires a high level of judgment and knowledge  of aquatic
systems.

3.2.4  Summary                                                             :

     The guidelines presented in this document offer a systematic way to
consider available data and design needs for possible field work.  The
strengths of the approach are that it is very flexible and relies on  common
sense and professional judgment.  The limitations of the  approach are that the
results are not quantified.  In addition, little guidance is provided on  the
approaches for extrapolating from available data to species and  effects of
concern,  and the specific criteria upon which to base conclusions  (e.g.,  NOEL,
LC50) are not defined.

-------
 Water Quality-based Permitting    EPA/OWRS 1985, 1987              Page C-28


 3.3  PERMIT WRITER'S GUIDE TO WATER QUALITY-BASED PERMITTING FOR TOXIC
      POLLUTANTS  / TECHNICAL SUPPORT DOCUMENT FOR WATER QUALITY-BASED TOXICS
      CONTROL


 3.3.1  Introduction

      Both  the Clean Water Act and promulgated Federal regulations require that
 all National Pollutant Discharge Elimination System (NPDES) permits include
 limitations to achieve all applicable state water quality standards.  All
 states  have numerical standards for some individual toxicants, as well as
 narrative  standards for pollutants.  One of the most common narrative
 standards  is that a state's waters shall be free from substances in
 concentrations or combinations toxic to humans, wildlife, or aquatic life.
 This  standard can be used to limit both individual toxicants and whole
 effluent toxicity.   The Permit Writer's Guide to Water Quality-Based
 Permitting for Toxic Pollutants (EPA/OWRS 1987) provides procedural
 recommendations  to  state and Federal NPDES permit writers.  The Technical
 Support Document (TSD) for Water Quality-Based Toxics Control  (EPA/OWRS 1985)
 provides additional guidance and explanation of the two basic  approaches  to.
 water quality-based toxics control: the whole-effluent approach and the
 chemical-specific approach.  Either or both approaches can be  used for setting
 effluent limits or  monitoring compliance.  This review describes only  the
 approaches  recommended to ensure that state waters are free from substances
 toxic to aquatic life.

      The whole-effluent approach to toxics control involves toxicity testing
 of  the  effluent.  The measure of whole-effluent toxicity, information  on
 mixing  zones, and design flow of the receiving waters are then used to
 estimate a wasteload allocation/total maximum daily load  (WLA/TMDL) for
 effluent discharge.  The chemical-specific approach involves use of a  water
 quality criterion (e.g., state numerical water quality criteria which  are
 often derived from  EPA ambient water quality criteria) and exposure modeling
 to  establish an effluent discharge limit.

 3.3.2   Description  of Method

      Receptor Characterization

      The initial step in the water quality-based approach to  toxic  effluent
 control is determining the level of water quality  that must be maintained to
 allow continuation  of the state-designated use  of  the water body  (e.g.,  cold
water fishery).  Further receptor characterization depends on whether  the
whole-effluent approach or the chemical-specific approach is  employed.   If the
whole-effluent approach is followed, the TSD recommends  use of three  different
 test  species so that a species sensitive to the toxicants in  the  effluent is
 likely  to be tested.  If the chemical-specific  approach  is  followed,  the
 receptor characterization is that associated with  the  development of the
numerical criteria  (see review of EPA/OWRS 1986 Ambient  Water Quality Criteria
methodology).

-------
Water Quality-based Permitting    EPA/OWRS 1985, 1987              Page  C-29

     For the whole-effluent approach, it is not possible to predict a. priori
which species is likely to be most sensitive because different species exhibit
different sensitivities to toxicants (e.g., trout are very sensitive to  oxygen
depletion but are relatively insensitive to certain toxicants).   An analysis
of species sensitivity ranges (as identified in the EPA Ambient Water Quality  •
Criteria documents) indicated that if tests are conducted on three particular
species (Daphnia magna. Pimephales oromelas. and Lepomis macrochirus), the
most sensitive of the three will exhibit an LC5Q value within one order  of
magnitude of the most sensitive of all species tested.  If fewer than three
species are tested, a safety factor of 10 should be applied to the lowest
observed LC5Q value to extrapolate to more sensitive species.  The TSO
recommends against using resident species for the whole-effluent toxicity
tests unless it is required by state statute or some other binding factor.
The reason is that testing of resident species is more costly, more difficult,
and subject Co more variability than testing of standard laboratory species.

     Hazard Assessment

     The hazard assessment of the water quality-based approach to toxics
control depends on whether the whole-effluent approach or the chemical-
specific approach is followed.  For the whole-effluent approach, toxicity  .
tests are conducted on three test species using a series of dilutions of the
whole-effluent.  For the chemical-specific approach, the hazard assessment has
already been conducted in the establishment of numerical ambient water quality
criteria (see review of EPA/OWRS 1986 Ambient Water Quality Criteria
methodology).

     For the whole-effluent approach, an effluent sample is collected and
diluted in test chambers; the dilutions are usually 100%,  30%, 10%,  3%,  1%,
and a control.  The receiving water is frequently used  to dilute  the  effluent
because it more closely simulates the effluent/receiving water interactions.
The required measures of effluent toxicity are  the LCjQ  (the  effluent
concentration expressed as the dilution at which 50%  of  the  test  organisms are
killed) and the no-observed-effect-level  (NOEL; the highest  effluent
concentration at which no unacceptable effect will occur even following
continuous exposure).  Because of the inverse relationship between toxicity
and the reference concentration (e.g., the  lower the  LC5Q  or the  NOEL,  the
higher the toxicity of the effluent), concentration-based  toxicity
measurements are translated into acute (TUa) or chronic (TUc) "toxic units."
The toxic unit is simply 100 divided by the  toxicity measure:

               TUa -  100             TUc  - 100
                      LC50                   NOEL

where the LC5Q or NOEL is expressed  as percent  effluent in the dilution water.
Thus, an effluent for which the 10%  dilution killed 50 percent of the test
organisms is an effluent containing  10 TUa.  An effluent contains 20 TUc if
the highest concentration that did not produce  adverse effects over a long
exposure period was a 5% dilution.

-------
Water Quality-based Permitting    EPA/OWRS  1985,  1987              Page C-30

     Exposure Assessment              ^

     Some States have numeric criteria for  whole  effluent  toxicity, often
stated as end-of-the-pipe acute toxicity  limits,  that  do not  depend on an
exposure assessment.  Otherwise,  effluent concentrations in both  the mixing
zone(s) surrounding the effluent discharge  and in the  remainder of the
receiving water body must be estimated on the basis  of the design flow of  the
receiving waters.   Design flow is a hydrological  condition which  describes a
low flow of a flowing water body and is calculated from the historical flow
record.  The level of effluent control is to be set  on a "worst case" exposure
scenario to protect aquatic life during low flow conditions,  when the dilution
potential of the receiving water body is  lowest.   Design flows can be
calculated using an EPA recommended computer simulation program (DFLOW)  or
other methods.  The goal of the exposure  assessment  is to  determine  the  lowest
flow expected for a specified period of time with a  specified frequency  of
occurrence for comparison with the reference toxic units.  The lowest  flow
averaged over any consecutive 7 day period  that is expected  to occur  in  a
typical 10 year period (7Q10) is the recommended design flow for  calculating
dilution for the chronic ambient water quality criterion or  for the  whole-
effluent identified NOEL.  The lowest flow  averaged over any 1 day  period  that
is expected to occur in a typical 10 year period (1Q10) is the recommended .
design flow for calculating dilution for the acute criterion or the  whole-"
effluent LC5Q value.

     Risk Characterization

     Many state standards allow a zone of mixing around the effluent discharge
point in which less stringent ambient water quality criteria apply than in the
remainder of the receiving water.  EPA's policy on mixing zones,  described in
the 1983 Water Quality Standards Handbook,  is that any mixing zone should oe
free from materials which cause acute toxicity to aquatic life.  Acute
toxicity is of concern for organisms passing through the mixing zone on a
daily or seasonal basis.  Both acute and chronic toxicity are of concern  for
the remainder of the receiving water body.

     Tiered testing, similar to that used under the Toxic Substances Control
Act (TSCA) when testing a new chemical product for potential hazard, is
recommended to provide a cost-effective method of obtaining  the  necessary data
for toxic effluent control.  At the screening level, the  goal  is to separate
situations in which impacts on aquatic systems are  improbable  from those  in
which impacts are possible or probable.  Screening  level  considerations
include the dilution potential of the receiving water,  the type  of industry,
the type and volume of industrial input, any existing  data on toxic
constituents in the effluent, and any history of  toxic impact on receiving
waters or compliance problems.  If, during  the screening  analysis, a case is
identified wherein  impacts on aquatic organisms  are possible or  likely,
definitive data gathering  is then required  using either the  whole-effluent
approach or the chemical-specific approach,  or both.

     In the whole-effluent approach,  the recommended  acute  criterion for  the
acute design flow (1Q10) is 0.3 TUa.  The  adjustment  factor  of approximately
one-third is used to extrapolate  from  a  50  percent  mortality level  (LC50) to a

-------
Water Quality-based Permitting    EPA/OWRS 1985, 1987              Page  C-31

1 percent mortality level (LC^).   The criterion can be applied at different
locations in  the receiving water depending on the dilution situation.  The
recommended chronic criterion for the chronic design flow (7Q10)  is 1  TUc.
The waste load allocation (WLA) requirement is calculated on the  basis of the
toxicity criterion and the dilution factor based on the receiving water  design
flow as well  as the effluent design flow.  A separate WLA is calculated  for
the acute and chronic exposure scenarios, and an effluent performance  level
that will meet each WLA requirement is back-calculated.  Permit limits are
derived from  the more restrictive performance level (the acute or the  chronic
design flow).

3.3.3  Operational Resource Requirements

     The effort and cost of following the recommended analysis and testing
procedures for NPDES permitting depends on the results of the dilution
screening analysis.  The TDS identif-ies five levels of dilution potential in
the receiving water body and recommends increasing numbers of toxicity tests
as the dilution potential of the receiving water declines.  Potentially, both
acute and short-term chronic toxicity tests might be required for three
species.  Compliance monitoring might also require effluent toxicity testing
on a monthly  basis with the one species determined to be most sensitive  to. Che
effluent.

3.3.4  Summary

     The Water Quality-Based Toxics Control methodology  includes  two
approaches to defining limits to toxic effluent discharges  into  surface
waters.  The  whole-effluent approach involves determining the toxicity  of the
effluent mixture using bioassays with three species of aquatic organisms.  The
chemical-specific method involves the application of state  water  quality
criteria for  the designated uses of the receiving water.  Each approach has-
advantages and disadvantages and is complementary to the other.   EPA
recommends using both approaches, as appropriate, to a given permitting
situation.

     The principal advantages of the whole-effluent approach compared with  the
chemical-specific approach are (1) the combined toxicity of all  constituents
in a complex  effluent is measured, (2) the bioavailability  of  the toxic
constituents  is assessed, and (3) the effects of synergistic or  antagonistic
interactions  of the effluent constituents  are accounted  for.

     The principal disadvantages of the whole-effluent approach  compared with
the chemical-specific approach are (1) treatment systems are  more easily
designed to meet chemical-specific requirements,  (2)  engineers and permit
writers are more familiar with chemical-specific approaches,  (3) properties of
specific chemicals in complex effluents  (e.g.,  bioaccumulation)  are not
assessed.

-------
 Biological Criteria        Ohio EPA 1987a, 1987b, 1988            Page  C-32


 3.4  BIOLOGICAL CRITERIA FOR THE PROTECTION OF AQUATIC LIFE

 3.4.1  Introduction

      Since 1980, Ohio EPA has been conducting biological evaluations of state
 surface water quality to quantify the attainment or non-attainment of state
 designated surface water uses.  Field measurements of the fish and
 macroinvertebrate sub-communities are used to calculate three indices of
 biological integrity: (1) Index of Biotic Integrity (IBI, based on the fish
 sub-community), (2) Modified Index of Well-Being (Iwb, also based on fish),
 and (3) Invertebrate Community Index (ICI, based on the macroinvertebrate sub-
 community).  Ohio EPA uses the three indices in conjunction with chemical-
 specific ambient water quality criteria and toxicity testing for discharge
 permitting to improve and maintain the biological integrity of the state's
 surface waters  (Ohio EPA 1987a, 1987b. 1988).

      Ohio EPA has found the indices to meet several important criteria.  The
 indices depend  on actual biological measures, rather than surrogate measures
 such  as contaminant concentration.  The measures indicate effects at several
 trophic levels.  The response ranges of the indices are suitable for the
 regulatory needs.  The indices are sensitive to the environmental conditions
 of  interest.  The indices are reproducible and precise within defined and
 acceptable limits.  Finally, the signal-to-noise ratio for the combination of
 the three indices is high.

 3.4.2  Description of Method

      Receptor Characterization

      The Ohio EPA definition of biological integrity depends on the biological
 conditions exhibited by the "least impacted" surface water habitats, rather
 than  "pristine" habitats which would represent unattainable conditions over
most  of the state.  Ohio EPA uses an ecoregion approach  to identify reference
aquatic communities, relying on Omernik's (1987) classification of aquatic.
ecoregions of the United States from maps of land-surface form, soils,
potential natural vegetation, and land use.  Within each of the five
ecoregions, three types of rivers/stream habitats are defined based on size
and water flow:  wading sites, boat sites, and headwater sites.

      The fish and macroinvertebrate sub-communities were selected for
evaluation of surface water quality because there is  sufficient information
concerning their life-histories, distribution, and tolerances and also because
 these sub-communities are dependent upon  the other sub-communities  (e.g.,
plants, microinvertebrates) for their well-being.  The  fish  sub-community is
the most conspicuous and is generally of  concern for  its commercial  or sport
value.

     The Index  of Biotic Integrity  (IBI)  incorporates  12 different metrics  of
the fish sub-community to derive a  final  IBI score.   The value  of each
individual metric measured at an evaluation site is  compared with the value
expected on the basis of the analysis of  "least  impacted"  reference sites in

-------
Biological Criteria        Ohio EPA 1987a,  1987b,  1988            Page C-33

the same ecoregion with the same water flow characteristics.  Ratings of 5, 3,
or 1 are assigned to each of the 12 metrics based  on  whether  the evaluation
site value approximates,  deviates somewhat  from, or deviates  strongly from the
expected value, respectively.   Expected values  are derived  from the data
collected at the "least impacted" reference sites. The  12  community metrics
were modified from those proposed by Karr (1981) to include measurements that
could be reliably made given the sampling gear  required  for each stream size.
The IBI metrics include the total number of species,  three  metrics  related to
the total number of species of a specified type of fish  (e.g.,  sucker, minnow,
sunfish),  the number sensitive (i.e., intolerant)  species,  the  percent
tolerant species, the percent omnivorous species,  the percent insectivorous
species, the percent top carnivore or pioneering species,  the total number of
individuals, the percent hybrids, and the percent  diseased individuals or  fish
exhibiting deformities, eroded fins, lesions, or external  tumors.

     The Index of Well-Being (Iwb) for the fish sub-community incorporates
four indices:  numbers of individuals, biomass, the Shannon diversity index
based on number, and the Shannon diversity index based on weight.   Number  and
biomass data are obtained from pulsed D.C.  electrofishing catches,  where
sampling effort is normalized on the basis of distance.   Ohio EPA recently
developed a modification of the Iwb that makes  the index more sensitive  to ,
environmental disturbances.  In the modified Iwb,  any of 13 highly tolerant
species, hybrids, or exotic species are eliminated from the numbers and
biomass components of the Iwb but still included  in the two Shannon diversity
indices.  Ratings are assigned to each of the four indices on the basis  of
similarity to the reference sites.

     The Invertebrate Community Index (ICI) is an index of the
macroinvertebrate sub-community as measured on artificial substrates
introduced into the surface water for a specified period of time.   The ICI is
a modification of the IBI for fish and consists of 10 metrics, including the
total number of taxa, number of mayfly taxa, number of caddisfly taxa, number
of dipteran taxa, percent mayflies, percent caddisflies, percent midges (tribe
tanytarsini), and percent tolerant organisms.  Mayflies, caddisflies, and
tanytarsinid midges are important components of undisturbed stream
macroinvertebrate sub-communities that range from highly to moderately
sensitive to pollutant stress.  Ratings are assigned to each of the 10 metrics
on the basis of similarity to the reference sites.

     Regional criteria for the IBI, modified,  Iwb, and  ICI were established on
the basis of the measurements of each metric from the reference sites.
Ecoregional criteria for the warmwater habitat (WH) use designation were
established as the 25th percentile value from  the reference  site values for
each ecoregion.  The exceptional warmwater  habitat (EWH) use designation
criteria were set at the 75th percentile value.   The 25th  percentile  for  the
WWH use designation was chosen to compensate for  the inclusion of  marginal
sites in the original  reference  site  data  base.   Ecoregional criteria for
coldwater habitats, however, have not yet  been developed.

-------
 Biological  Criteria        Ohio EPA 1987a, 1987b,  1988            Page  C-34

     Hazard Assessment

     A hazard assessment is not part of the biological criteria methodology.
 However,  the biological criteria are intended for use in conjunction with
 chemical  identification, chemical criteria, and toxicity testing to assist
 water quality management decisions.

     Exposure Assessment

     Exposure characterization is not part of the biological criteria
 methodology.  The fish and macroinvertebrate sub-communities represent
 relatively  long-lived organisms that have integrated the effects of continuous
 exposure  to the pollutant and other stressors over a period of years.

     Risk Characterization

     The  biological indices from an evaluation site can be used in several
 ways.  The  indices can be compared with the criteria values for the ecoregion
 to establish the attainment or non-attainment of a designated use.  The
 indices for upstream and downstream locations can be compared to help identify
 a hazardous discharge.  Indices from the same site can be'followed over time
 to measure  the effectiveness of a regulatory control.  For some types of   . :
 pollutants, the ICI measure of the macroinvertebrate sub-community is a more
 sensitive indicator than either fish index, and for other types of stress, the
 fish sub-community indices can be more sensitive.  All three indices are
 therefore used to indicate the quality of Ohio surface waters.  Figure C3-2
 illustrates how the three indices have been used to illustrate the general
 improvement in water quality over the last 10 years at selected sampling
 stations  in the state of Ohio.  Figure C3-3 illustrates how the indices can be
 used to document environmental degradation associated with one or more point
 sources of pollutant stress with distance along a river.

 3.4.3  Operational Resource Requirements

     Ohio EPA provided a cost comparison of fish sub-community and
macroinvertebrate sub-community evaluations of water quality with chemical and
physical  sampling of surface water and acute and acute/chronic bioassay  tests
on effluents of the type used for National Pollutant Discharge Elimination
 system (NPDES) permitting.  While chemical/physical sampling  (4-6 samples per
site) costs between $1,500 and $1,700, and bioassays can  run  from $3,200  for  a
screening level assay to $8,000 - $12,000  for a 7-day bioassay, a  -
macroinvertebrate evaluation typically costs $700 and fish community sampling
costs Ohio EPA between $670 and $900 (2 to 3 passes per site).  Thus,  the
biological evaluation methodology is cost  competitive with the more  commonly
used measures of surface water quality.  The initial development  of  Biological
Criteria, however, required a substantial  effort in sampling  a  large number of
 "least impacted" reference sites.

-------
Biological Criteria
Ohio EPA 1987a, 1987b, 1988


      FIGURE C3-2
                                                                   Page  C-35
       BIOLOGICAL IHDICES OF SURFACE WATER OJUALITY IN THE SCIOTO RIVER
                           (Source:  Ohio EPA 1988)
                     H


                     Q

                     H
                     O
                     UJ
                     H
                     u.
                     H
                     O
                     O
                     z
                                   r..,,.,,.l....l,.,.l,,.,l,,,.,....,....,....,,...,,,.I
                                      Y  E  A
 Fieure C3-2    Results of the Invertebrate Community Index  (ICI),  Index of
 Biotic Integrity (IBI),  and Modified  Index of Well-being (Iwb)  at selected
 !amp  ing  locations in the middle Scioto River between 1974 and  1987.   Shading
 indicates boundaries between exceptional (EWH), good (WWH).  fair, poor, and
 very  poor conditions and the variability of each index.  Sampling was
 conducted during July-October of each year.

-------
 Biological  Criteria
Ohio EPA 1987a,  1987b,  1988

      FIGURE C3-3
Page C-36
      LONGITUDINAL TRENDS IN BIOLOGICAL INDICES OF  SURFACE WATER QUALITY
                            IN THE CUYAHOGA RIVER
                           (Source:   Ohio  EPA  1988)
                              1" 'f I ')' " I" " M 1" i""
                              RIVER MIl_E
Figure C3-3.  Longitudinal trend of the Invertebrate Community  Index  (1984,
1986) and Modified Index of Weil-Being (fish; 1984, 1985, and 1986) in  the
Cuyahoga River study area.  Shading indicates boundaries between  exceptional
(EWH),  good (WWH),  fair, poor, and very poor conditions and  the variability of
each index.  Sampling was conducted during June-September of each year.
Horizontal arrow indicates direction of flow; environmental  influences  are
indicated at the top.

-------
Biological Criteria        Ohio EPA 1987a, 1987b,  1988            Page  C-37

3.4.4
     Ohio EPA has developed and is using three indices of biological integrity
to measure attainment of the goals of the Water Quality Act (WQA) .   Unlike
chemical criteria which serve as surrogate measures of the attainment of the
biological goals of the WQA or effluent toxicity testing to control
chemicaldischarges ,  the indices incorporate direct measurements of the
structure of biological communities, representing a top-down approach.  There
are several advantages to using measurements of the fish and invertebrate
communities to assess water quality.  One advantage is that the organisms have
been exposed continuously to the actual conditions and history of pollutant
stresses in the receiving waters.  Extrapolation between responses of
organisms in the laboratory and responses of organisms in the field are not
required.  In addition, stressors other than toxic substances for which
laboratory data are available can be- detected.  The organisms integrate
exposure over time and space, and the condition of the resident community is
the result of the full history of environmental conditions, including both
common and extreme events .

     Some difficulties that have discouraged the development of biological.-.
criteria and community- level indices in the past have been overcome through
standardization of field sampling methods, acceptance of several types of
measures as indicative of biological integrity, calibration of indices on the
basis of ecoregion and surface water body type, and measurement of  the indices
for a large number of reference sites.  Over the past 10 years, Ohio  EPA has
found that the signal-to-noise ratio and reproducibility of the indices are
sufficiently high to provide useful indications of changes in  the biological
community in response to pollutants or other stresses.

-------
Biological Criteria        Ohio EPA 1987a,  1987b,  1988            Page C-38


3.4.5  References

Karr, J.R.  1981.  Assessment of biotic integrity using fish communities.
     Fisheries 6(6):21-27.

Larsen, D.,  Omernik, J.M., Hughes, R.M.,  et al.  1986.  Correspondence between
     spatial patterns in fish assemblages in Ohio streams and aquatic
     ecoregions.  Env. Mgmt. 10(6):815-828.

Omernik,  J.M.   1987.  Ecoregions of the conterminous United States.  Ann.
     Assoc.  Amer. Geogr. 77(1):118-125.

Whittier, T.R., Larsen, D.P., Hughes, R.M., et al.  1987.  The Ohio Stream
     Regionalization Project:  a Compendium of Results.  US Environmental
     Protection Agency, Freshwater Research Laboratory, Corvallis, OR.
     EPA/600/3-87/025.  163 pp.

-------
 Fish Flesh  Criteria               NYS/DEC 1987                    Page C-39

 3.5  NIAGARA RIVER BIOTA CONTAMINATION PROJECT:  FISH FLESH CRITERIA FOR
      PISCIVOROUS WILDLIFE  (NYS/DEC 1987)

 3.5.1  Introduction

      To interpret  the results of the Niagara River fish tissue monitoring
 program,  the Niagara River Toxics Committee (NRTC 1984) of New York State
 recommended that residue criteria be established, if none were available, for
 the  chemicals that had been detected.  The two primary objectives of this
 report  were (1) to develop fish flesh criteria for 19 organochlorine chemicals
 that will protect piscivorous wildlife, and (2) to evaluate a methodology for
 deriving such criteria where toxicology data are.unavailable for wildlife
 species of  concern.  In the past, fish flesh criteria for the protection of
 wildlife generally have been derived from wildlife feeding studies, of which
 few  are available.  The NYS/DEC approach is to use the extensive laboratory
 animal  toxicology data base employed'for the derivation of human health
 criteria to extrapolate to wildlife species.  In the following sections, we
 review  this methodology for deriving fish flesh residue criteria.

 3.5.2   Description of Method

      Receptor Characterization

     A  list of 18 species of piscivorous wildlife which are current or  former
 inhabitants of the Niagara River valley were selected as the ecological
 targets  of  concern.  For each of these species, body weight, daily food
 consumption by weight, and food habits were determined.  From these data, the
 mammal  and  bird with the greatest ratios of daily food consumption to body
 weight  were selected for use in calculation of fish flesh criteria.  Mink,
 with  an average body weight of 1 kg and daily food consumption of 0.15  kg/day,
 were, selected as the representative mammalian target.  Because several  species
 of birds consume an amount of food equal to about 20 percent of  their body
 weight  daily, a "generic" bird was selected with a weight of 1 kg and a daily
 food consumption of 0.2 kg.

     Hazard Assessment

     The results of laboratory animal feeding experiments are extrapolated  to
 fish flesh  criteria for wildlife using the following general formula:

 (Toxicitv Value (mg/kg-dav) x Uncertainty Factor x Target Species Weight (kg)1
                       Target Species Daily Intake (kg/day)

The Toxicity Value is either a no-observed-effect-level  (NOEL),  lowest-
observed-effect-level (LOEL), or cancer risk-based dose  corresponding to a
1/100 risk  of cancer.  Where a chronic NOEL for a sensitive  species  is
unavailable, the uncertainty factor is applied as follows:

     0.1  is used to estimate a chronic NOEL  from subacute  data;

     0.2  is used to estimate a chronic NOEL  from a  chronic  LOEL;  and

-------
 Fish Flesh Criteria               NYS/DEC 1987                    Page C-40

     0.1  represents the interspecies uncertainty factor to  use when  chronic
          data are available from only one or two species in the same class.

 Only laboratory data from mammalian species are used to extrapolate  to a
 mammalian wildlife species (i.e., mink), and only laboratory data from birds
 are used to extrapolate to a wildlife bird species (i.e., the "generic"  bird).

     Toxicity endpoints of concern included mortality,  body  weight gain, liver
 and kidney weight (as a percentage of body weight),  liver and kidney
 micropathology, and reproductive losses.  The interspecies uncertainty  factor
 is based on a literature review that supports a 10-fold or more range in
 sensitivity of species to thoroughly tested organochlorines.  The factor of
 0.1 was selected to estimate a chronic NOEL from subacute data on the basis of
 a review by Weil and McCollister (1963) in which the authors found that  a 10-
 fold factor would cover 95 percent of. the chemicals  tested for short-term
 (e.g.,  30 to 90 days) versus long-term (e.g., two years or lifetime) exposure.
 Weil and McCollister (1963) also presented data that justified using a  factor
 of 0.2 to extrapolate from a LOEL to a NOEL (all ratios of LOEL/NOEL were 10
 or less, and 92 percent were 5 or less).  The NYS/DEC also recommends using
 supplementary data when available, such as epidemiological field studies.

     As one method of validating this approach, NYS/DEC compared the fish
 flesh residue criteria developed for five chemicals, using the method outlined
 above including the uncertainty factors, with toxicity data for the actual
 target wildlife species of concern.  For PCBs, DDT,  aldrin/dieldrin, and
 mirex,  but not endrin, at least one of the lab species-based non-carcinogenic
 criteria was lower than target species criteria.  In the case of endrin, the
 mallard exhibit  3. very high sensitivity to the chemical.  Thus, using
 laboratory animal data in conjuction with uncertainty factors should result  ir
 fish residue levels that would usually be protective of wildlife species.
 This method does not, however, address the possible additive or synergistic-
 effects of mixtures of similar compounds or the susceptibility  of wildlife in
 naturg to toxic substances.

     Exposure Assessment

     The most sensitive bird (i.e., "generic") and mammal (i.e., mink)  species
 are assumed to consume a diet consisting of 100 percent  fish.   The NYS/DEC
points out that biomagnification of contaminants might  continue in  the
 terrestrial food chain, such as when eagles consume gulls that have  consumed
contaminated fish.  The method for deriving fish  flesh  criteria outlined above
 is not protective of terrestrial animals in higher  trophic  positions than the
piscivorous target wildlife species.

     Risk Characterization

     To assess risk to wildlife  fish consumers near  the Niagara River,  the
 fish flesh criteria were compared  to residues in Niagara River fish (e.g.,
 spottail shiners, alewives, smelt, coho  salmon)  by  the quotient method (see
Review 7.1.1).  Extrapolations of  residue  levels in spottail shiners (which
were the only species sampled on a regular basis over  the years) to residue
 levels in other fish species were  accomplished by assuming that all of the

-------
 Fish Flesh Criteria               NYS/DEC 1987                    Page C-41

 organochlorine compounds were sequestered in the lipid portion of the fish,
 and  using a  relative  lipid content correction factor.  The selection of a
 1/100 cancer risk  level as an acceptable cancer risk for wildlife was a
 preliminary  decision  and will be studied further.

 3.5.3 Operational Resource Requirements

      The methodology  for setting fish flesh residue criteria is simple and
 easy to follow.  Large toxicity data bases exist for mammalian laboratory
 species because these data are used to assess human toxicity.  Fewer data are
 available for laboratory bird species for compounds other than pesticides.

 3.5.4 Summary

      The guidelines developed to calculate fish flesh residue criteria allow
 extrapolation from a  large laboratory animal toxicity data base to fill a
 large data gap in available wildlife long-term feeding studies.  The
 guidelines might not  be sufficiently protective of wildlife species that
 consume piscivorous wildlife species, however.  The guidelines are not
 concerned with what effects, if any, will occur in the ecosystem if
 concentrations reach  or exceed the benchmarks.  Nor does the risk assessment
 portion address the problem of exposure to multiple contaminants.  Criteria
 are  developed only for chronic dietary exposure scenarios.  The calculation
 schemes themselves are straightforward.  However, validation of input  data
 requires a high level of expertise in the area of aquatic toxicology.

      Strengths of the approach are its wide applicability and apparent
validity.  Limitations are that community or ecosystem effects are not
 directly assessed, that guidelines have not yet been established for  chemical
mixtures, and that validation efforts have thus far been limited.

      Fish residue criteria developed using this methodology  could be  used in
conjunction with bioaccumulation factors to adjust chronic water qualtity
criteria for substances with a strong tendency to bioconcentrate.

 3.5.5  References

Weil, C., and McCollister, D.  1963.  Relationship between short and long-term
      feeding studies  in designing an effective toxicology test.  Agric.  Food
      Chem. 11:486-491.

-------
 SEP for Ecological Risk             EPA/OPP 1986                   Page  C-42


                4.0  METHODS/ASSESSMENTS DEVELOPED UNDER FIFRA

 4.1  STANDARD EVALUATION PROCEDURE FOR  ECOLOGICAL RISK ASSESSMENT (EPA/OPP
      1986)

 4.1.1   Introduction

     The Office of Pesticide Programs (OPP) has developed a Standard
 Evaluation Procedure for carrying out ecological risk assessments to evaluate
 environmental  toxicology and effects data submitted in support of pesticide
 registration.  The approach is a modified quotient method in which estimated
 environmental  concentrations (EECs) are compared to environmental toxicity
 endpoints; the resulting ratios are evaluated according to regulatory risk
 criteria (RRCs) established by regulation or, in the case of endangered
 species, by a  Memorandum of Understanding between EPA and DOI.

     OPP developed this approach because of several features unique to the
 ecological risk evaluation of pesticides.  Since pesticides are used by
 deliberate and broadscale introduction  into the environment, and since
 pesticides are by definition toxic to at least some component: of the
 biosphere, a basic set of environmental test data  is required for all
 pesticides before use is allowed.  The  approach is designed to identify
 pesticides with high potential for ecological impacts, based on acute
 toxicity, which would then require further testing and refinement of the risk
 assessment.  Finally, separate regulatory risk criteria are used to make
 regulatory decisions when endangered species are  the receptors of concern.

 4.1.2   Description of Method

     Receptor  Characterization

     Both aquatic and terrestrial receptors are considered under this method.
 Assessments are focused at the population level,  although the value of
 individual members of endangered species is considered by using a more
 stringent RRC.  Life habit characteristics are considered when characterizing
 potential receptors.  For example, potential aquatic receptors are  identified
 and differentiated based upon the habitat in which they exist (cold or  warm
 water,  salt or fresh water).  Terrestrial species  are identified and
 characterized  based upon habitat and dietary characteristics.  Indicator
 species thaC most closely represent the characteristics of potential non-
 target  receptors are selected for the risk assessment.  Seasonal or life-cycle
 characteristics and the geographic location of the potential receptors  are not
 considered.

     Hazard Assessment

     Hazard assessments are conducted at the population level, and acute  and
chronic toxicity are the endpoints considered; dose-response data  and
community and  ecosystem responses are not evaluated.  In  addition,  the
 influence of potential toxicity modifying factors (e.g.,  pH, hardness,
behavioral modifications) is not considered.

-------
SEP for Ecological Risk             EPA/OPP 1986                   Page C-43


     Toxicity cests that may be required for assessment  are  shown  in Table
C4-1. The tests are arranged in a tiered system which  progresses from basic
laboratory tests to applied field tests.   In general,  the  first tier consists
of tests to determine acute endpoints (e.g.,  LC5QS)  using  common laboratory
organisms; the second tier consists of tests for  sublethal effects or tests on
specific organisms; and the third tier includes field  tests.   The  results  of
each tier of tests are evaluated to determine the potential  of the pesticide
to cause adverse effects and to determine whether further  testing  is needed.

     Exposure Assessment

     The exposure assessment is also conducted in a tiered manner.  In  the
lower tiers, environmental exposure concentrations (EECs)  can be estimated
using modeling, whereas field monitoring data may be required for  the highest
tier.  In the lower tiers, EECs are determined based on fate and  transport
data (for aquatic systems) and residue chemistry and monitoring data (for
terrestrial systems), as well as the rate, frequency,  timing, and  method of
pesticide application.  Exposure pathways are via water (for aquatic species)
and via food (vegetation and nontarget insects) for terrestrial species.   EECs
in aquatic systems are estimated using hydrologic computer models  developed by
EPA (EXAMS and SWRRB).  These models estimate minimum and maximum
concentrations over time.

     EECs for the first tier in terrestrial systems are derived using
pesticide residue profiles based upon published monitoring data.   This  method
uses the maximum and mean estimates of pesticide concentration immediately
following application.  Different estimates of residue concentrations are
derived for different types of vegetation and nontarget insects.   The residue
estimates are the EEC and are developed for those types of vegetation and
insects believed to comprise the diet of the nontarget species.   EECs are
compared to RRCs derived from dietary concentration dose-response data.   If
only dosage data are available, these values are converted into dietary
concentration values using assumed body weight and food intake values for the
nontarget species.

     Risk Characterization

     Risks are estimated by comparing the  EEC  to a set of regulatory risk
criteria (RRC).  The RRCs for acute  toxicity are equal to the LCjQ or U>50
divided by a safety factor of either 5, 10, or 20.  The safety factors were
derived by examining a cross-section of existing acute  lethality  dose-response
data and determining the fraction of the median  lethal value that corresponds
to mortality in 0.1% of the population.   (Mortality of 0.1%  was regarded  as
sufficiently protective of a population.)   For the  typical  (average)
dose-response curve, a value one-fifth of  the  median  lethal  value corresponds
to mortality in 0.1% of the population.   Hence,  a  safety  factor of  five  is
applied to the acute toxicity value  to derive  an RRC.   An additional  safety
factor of two is used for aquatic species  because,  it was reasoned,  these
species are less capable of limiting their exposure to contaminants through

-------
 SEP for Ecological Risk             EPA/OPP 1986                   Page C-44


                                  TABLE C4-1

                WILDLIFE AMD AQOATIC  ORGANISM DATA REQUIREMENTS


 Avian  and Mammalian Tests

     Avian  single-dose  oral LD50
     Avian  dietary LC5Q
     Wild mammal  toxicity
     Avian  reproduction
     Simulated  and actual field testing
     Honey  bee: acute contact U>5o
     Honey  bee:   toxicity of foliar  residues

 Aquatic Organism Tests

     Freshwater fish acute  toxicity
     Freshwater invertebrate acute toxicity
     Estuarine/marine organism acute toxicity
     Fish early life-stage  study
     Aquatic invertebrate life-cycle study
     Aquatic organism bioconcentration
     Simulated or  actual field testing
Source:  40 CFR 157.145 and EPA/OPP 1986.

-------
 SEP  for Ecological Risk             EPA/OPP 1986                  Page C-45

 food switching or by moving out of treated areas (e.g.,  ponds).   Safety
 factors of 10 and 20 are used for terrestrial and aquatic  endangered species,
 respectively.  These higher safety factors are used for  endangered species
 because even a single death in these species is considered to be  of special
 concern.  There is no safety factor applied to chronic no-effect-level
 toxicity values to account for the uncertainty associated with laboratory-co-
 field extrapolations.

     If the EEC exceeds the RRC, a risk is presumed to exist and further
 testing may be required.  The degree of risk is not addressed.  Using  this
 approach, potential risks to aquatic and terrestrial organisms following
 exposures to a single chemical via a single route of exposure are evaluated;
 multiple chemical exposures and multiple pathways are not considered,  and,
 therefore potential antagonistic, synergistic, or potentiating interactions
 are  not considered.

 4.1.3  Operational Resource Requirements

     The operational resource requirements of the Standard Evaluation
 Procedures approach should be low to moderate for chemicals for which toxicity
 information already exists.  Operational resource requirements will be much
 higher for new chemicals for which testing will be required.  The approach
 would be relatively simple to implement.

 4.1.4  Stimnpary

     The Standard Evaluation Procedures for evaluating  ecological risks
 proposed by EPA's Environmental Effects Branch  is a quantitative risk
 evaluation approach.  The primary advantages of this  approach are that ic  is
 relatively simple to use.  In the first tier assessment,  it  uses acute
 toxicity data that are readily available  for many chemicals.  In addition,-
 this approach considers the characteristics of  potential  receptors when
 selecting indicator species and determining  terrestrial exposures.  To
 extrapolate to effects of chronic exposure  from acute toxicity  data,  acute
 LD5Q or LC50 values are divided by safety factors.  A safety factor of 5  is
 used for acute data from birds and mammals, while  a  factor of 10 is used  for
 aquatic organisms because they cannot  avoid exposure  as easily.  An additional
 safety factor of 2 Is applied if an  endangered species  might be at  risk.   Mo
 safety factor is applied to chronic  no-effect-levels  determined in  the
 laboratory.

     The Standard Evaluation Procedures,  however,  have  several limitations.
Many of these limitations are inherent weaknesses of the quotient method;
 others are unique to this method.   Some of the major limitations of this
 approach are:

          The method does not compensate  for differences between laboratory
          and field populations.

          It cannot be  used  for estimating indirect effects  of  toxicants, such
          as food chain bioaccumulation.

-------
SEP for Ecological Risk             EPA/OPP  1986                   Page C-46

          It has unknown reliability (i.e.,  has not been validated) and does
          not quantify uncertainties.

          It does not account  for  other  ecosystem effects  (e.g., predator-prey
          relationships,  community production/metabolism,  structural  shifts,
          etc.).

          It does not consider factors  (biotic and abiotic)  that might
          influence toxicity.

          Only one exposure  pathway is  considered for  aquatic  species and one
          for terrestrial species.

          Spatial variation  in contaminant concentration is  not considered.

          Multiple chemical  exposures-are not considered.  While this is
          sufficient for evaluating the  potential effects  of application  of  a
          single  pesticide,  it would not be  applicable for situations where
          concomitant exposure to  more  than  one chemical might occur.

-------
 CMRA                      Onishi et al. 1982, 1985               Page  C-47


 4.2   COMPUTER-BASED ENVIRONMENTAL EXPOSURE AND RISK ASSESSMENT
      METHODOLOGY FOR HAZARDOUS MATERIALS (CHEMICAL MIGRATION
      RISK ASSESSMENT; Onishi et a!- 1982, 1985)

 4.2.1   Introduction

      The Chemical Migration Risk Assessment  (CMRA.) methodology has two stated
 objectives as described by Onishi et al. (1982): (1) to predict the occurrence
 and duration of pesticide concentrations in  surface waters receiving runoff
 from  agricultural lands, and (2) to develop  a preliminary risk assessment
 procedure to predict the potential damage to aquatic biota.  Although these
 were  the stated purposes, the methodology can be used with little or no
 modification to evaluate the impact of any organic chemical which enters water
 from  land.

     The methodology is actually a series of models developed for EPA Athens
 Laboratory by Batelle Northwest which may be used in conjunction with other
 models  developed by the U.S. Department of Agriculture or Nuclear Regulatory
 Commission.  The algorithms have also been -incorporated in the Center for
 Exposure Assessment Modeling (CEAM) - supported model HSPF (Hydrologic
 Simulation Program - FORTRAN).  The basic architecture of the methodology i's
 shown in Figure C4-1.  Individual models from the methodology can be linked
 together in various fashions depending on the type of water body and
 dimensionality of the system.  The methodology has been documented extensively
 (Table  C4-2); however, the most important overview documents are Onishi et al.
 (1982 and 1985).

 4.2.2   Description of Method

     Receptor Characterization

     The methodology is more hydrologically  than biologically oriented and
 thus is weak in its receptor characterization components.  It can consider
 freshwater, estuarine, or marine systems.  Since  the output  is a probabilistic
 risk assessment, it can deal with both  individual or population risks if the
 size of the population is known.  The operator has considerable flexibility  in
 choosing receptors and time frames.  For example, risk to  an early  life  stage
 (ELS) of a particular species could be  assessed if toxicity  data  and
 sufficient information concerning the space-time  location  of the  ELS  were
 known.

     Hazard Assessment

     The model basically integrates acute  (LC50)  and chronic (MATC)  values
 into a  time-dose-response curve.  Only  three endpoints,  "safe",  "mortality",
 and "sublethality" are used, although  these  could be expanded.   No toxicity
modifying factors are considered.  Uncertainty  is considered implicitly by
using safety factors in developing MATCs or  extrapolating between 1X50 values
obtained under different time frames.   Many  of  the  apparent  problems with  the
hazard assessment component (e.g., failure to  consider  other endpoints or  che

-------
 CUBA
        Onishi ec al.  1982,  1985

               FIGURE C4-1

SCHEMATIC DIAGRAM OF THE CMRA METHODOLOGY
   (Adapted from:  Onishi e£ a4.  1985)
Page C-48
INPUT DATA

Terrestrial:
                                   ANALYSIS
     Meteorological information
     Contaminant data
          application rate
          physical properties
     Watershed characteristics
                               Overland Contaminant
                               Transport Modeling
Aquatic:
     Channel characteristics
     Sediment characteristics
     Containment properties
     Boundary conditions
          flow
          sediment
          containment
                               Surface Water
                               Contaminant Modeling
                                                 Contaminant Concentrations
Aquatic Toxicological Data:
     LC50
     MATC
                                                           1
                               Risk Assessment
                                                           T
                                                  Estimates  of  Lethal  and
                                                  Sublethal  Damages  on
                                                  Aquatic  Biota

-------
CMRA                      Onishi et al. 1982, 1985               Page C-49

                                  TABLE C4-2

                            SELECTED BIBLIOGRAPHY

Onishi, Y.,  Olsen, A.R.,  Parkhurst, M.A.,  and Whelan, G. (1985) Computer Based
Environmental Exposure and Risk Assessment Methodology for Hazardous
Materials. Jour. Hazardous Materials 10: 389-417.

Onishi, Y.,  Brown, S.M.,  Olsen, A.R.,  Parkhurst, M.A.,  Wise, S.E., and
Walters, W.H. (1982) Methodology for Overland and Instream Migration and Risk
Assessment of Pesticides. EPA-600/3-82-024.

Onishi,Y. and Wise, S.E.  (1982) User's Manual for the Instream Sediment -
Contaminant Transport Model Seratra. EPA-600/3-82-055.

Onishi, Y. and Wise, S.E. (1982) Mathematical Model, SERATRA. for Sediment
Contaminant Transport in Rivers and its Application to Pesticide Transport in
Four Mile and Wolf Creeks in Iowa. EPA-600/3-82-045.

Olsen, A.R.  and Wise, S.E.  (1982) Frequency Analysis of Pesticide
Concentrations for Risk Assessment (FRANCO Model).
EPA-600/3-82-044.

-------
 CMRA                     Onishi et al.  1982,  1985               Page  C-50

 lack of  inclusion of a true exposure-response  curve)  are not inherent  in the
 methodology--given more data and users who are biologically oriented,  several
 of  the apparent problems could be overcome.

      Exposure Assessment

      The methodology excels at exposure assessment since many of the component -
 models were developed specifically for this purpose.   The user can select from
 a wide range of hydrologic solute transport models both in overland flow and
 in  surface water.  If the hydrodynamics are complex,  it is relatively simple
 to  link a hydrodynamic model with the rest of the methodology.  The output is
 typically stochastic although it could be forced to be deterministic.   In a
 typical application, this output is in the form of the probability of
 occurrence and duration of specific toxicant concentrations; thus there is a
 de  facto consideration of uncertainty. The exposure component has been
 verified with two pesticides: toxaph'ene and Alachlor.  Various models used in
 the  exposure component have been validated by comparison of field results to
 predicted values; however, the entire component has not been validated.  If
 required, the exposure models can be calibrated by manipulation of input
 variables.

     Risk Characterization

     CMRA uses probabilistic risk assessment to evaluate impacts on aquatic
 life. In this component, the model known as FRANCO takes the  time-dependent
 output of the exposure models and calculates the number of  times and  fraction
 of the time that concentration-duration levels (e.g., 96 hour LC50) are
 exceeded.  Risk is then calculated as the  frequency of occurrence of  an event
 (e.g., exceeding an MATC) and its consequences (e.g., mortality). Certain
 assumptions are used in applying this method,  including: a  96 hour cutoff
 between acute and chronic; concentrations  less than the MATC  are "safe";
 concentrations between the MATC and the concentration-duration curve  result in
 "sublethality" or "damage"; and concentrations over the concentration-duration
 curve result in "mortality".  If the size  of the population is known,  this
 leads to prediction of the number of effects.   The probabilities shown on  the
 output can also be interpreted as risk to  an individual.   If  toxicological
 data on a chemical mixture are available,  then the effect  of  the mixture  can
be assessed.  As it stands, the methodology is limited  to  exposure  through
water.  Food chain exposure is not considered.

4.2.3   Operational Resource Requirements

     These depend on which of the overland transport  and/or surface water
 solute transport models are selected.  A mini/mainframe would be  required to
have the flexibility to use all model components.  Since  the methodology is
most sophisticated with respect to exposure modeling,  an experienced
hydrologist probably would be required to  run  the  models  and interpret the
 results.

-------
CMRA                      Onishi et al. 1982, 1985               Page C-51


4.2.4  <;"BP'ftry

     Both the overland transport and surface water solute transport components
were developed independently of the risk assessment (FRANCO) component.  The
aquatic toxicology input is also independent.  Therefore, use of the
methodology should not be considered to be restricted to the models originally
available (e.g.,  TODAM, SERATRA, FETRA, FLESCOT or Mixed Tank Models). The
strongest component of the methodology is the FRANCO model, a probabilistic
risk assessment which has considerably more utility and power than
methodologies using quotients.  It appears to be quite flexible and adaptable
to terrestrial receptors, mixtures of toxicants, and even ecosystem effects
given sufficient information.  The overall methodology has been verified for
two pesticides: coxaphene and Alachlor; it has not been validated, however.
Although it presently considers as endpoints only "safe", "mortality", and
"sublethaiity", it could be expanded-to include such parameters as impacts on
target organs or specific disease states if the toxicological data were
available.

-------
 Sensitive Environments             EPA/OSW 1987a               Page  C-52

                5.0  METHODS/ASSESSMENTS DEVELOPED UNDER RCRA

 5.1   POTENTIAL FOR ENVIRONMENTAL DAMAGE:  PROXIMITY OF NINE SITES TO
      SENSITIVE ENVIRONMENTS (EPA/OSW 1987a)

 5.1.1   Introduction

      ICF Incorporated has developed for EPA's Office of Solid Waste  a
 qualitative approach for ecological assessment that is based on the  proximity
 of sensitive environments to potential sources of contaminants.  The approach
 is most appropriate for screening-level analysis, and has been used to
 preliminarily assess the potential for environmental impacts from oil and gas
 and mining activities.

     The term sensitive environment refers to environmental areas that are
 either ecologically critical, unique,-or vulnerable; are of particular
 cultural significance; or are set aside for the purpose of conservation.   The
 assessment approach is based on the concept that actual or potential impacts
 to sensitive environments are generally of greater concern to society than
 comparable impacts in other environmental areas.  Waste sources near, sensitive
 environments are regarded as having a greater potential for environmental
 impact.  Although the proximity of sensitive environments to. waste sources--Is
 not an explicit criterion for determining ecological risk, it  is an important
 consideration.

     The approach is not a complete ecological risk assessment methodology
 because exposure and hazard assessments are not conducted.  It does, however,
 provide potentially useful concepts for receptor characterization and risk
 determination.

 5.1.2  Description of Method

     Receptor Characterization

     Four categories of sensitive environments were identified,  encompassing
both aquatic and terrestrial areas:  endangered and threatened species
habitats; wetlands; National forest system lands; and  National park system
 lands.  For any particular geographic area, sensitive  environments  can be
 identified using maps or available data bases.  For example,  information
published by the U.S. Fish and Wildlife Service  (USFWS) can  be used to
 identify endangered and threatened species habitats.   The USFWS  has  identified
 the historical ranges of approximately 400 endangered  and  threatened species
and the critical habitats for 96 species.  Also,  the Nature  Conservancy
maintains a data base that can be used  to  identify  endangered and threatened
species habitats for any given location.  Wetlands  can be  identified using
U.S.  Geological Survey 7.5 minute quadrangle maps or quadrangle  maps published
by the National Wetlands Inventory (USFWS).  National  forests and parks  also
can be located on quadrangle maps.

-------
Sensitive Environments             EPA/OSW 1987a               Page C-53


     Risk Characterization

     Under this assessment scheme, the degree of risk posed by any contaminant
source is qualitatively assessed using the spatial relationship between the
source and the receptor (sensitive environment).  The potential for
environmental damage increases as the distance to the sensitive environment
decreases or as the number of proximate sensitive environments increases.

5.1.3  Operational Resource Requirements

     This approach is based on information that is readily available for
virtually all areas of the United States.  The effort and costs for obtaining
and interpreting the information are low.

5.1.4  Summary

     This approach is an easily-implemented, low-cost, qualitative method  for
ranking the potential for waste sites to impose adverse impacts on valuable
communities and portions of ecosystems.  The potential for. impacts is
determined qualitatively based on the proximity of sensitive environments  tp  a
contaminant source.  Because no absolute criteria relating distance to risk
can be established without consideration of waste characteristics and exposure
pathways, the approach is limited to use as a comparative screening analysis
where several contaminant sources are being evaluated.  The approach is not
precise and has numerous other limitations  (e.g., no hazard or exposure
assessments) that make it applicable only to situations requiring  rough
screening analyses.

-------
 HWT Risk-based Variance            EPA/OSW 1987               Page C-54


 5.2  VARIANCE FROM THE SECONDARY CONTAINMENT REQUIREMENTS OF HAZARDOUS
      WASTE TANK  SYSTEMS:  VOLUME II:  RISK-BASED VARIANCE (EPA/OSW 1987b)


 5.2.1  Introduction

      IGF  Inc.  prepared guidelines for EPA's Office of Solid Waste to estimate
 environmental  risks posed by the release of waste constituents from hazardous
 waste tanks.   The  approach  is based on the work of Barnthouse et al.  (reviewed
 in  Section 7.1.1 of this appendix) and EPA/OPP (reviewed in Section 4.1  of
 this  appendix).  The approach uses the quotient method in which estimated
 environmental  concentrations (EEC) are compared to reference concentrations
 (RC)  believed  to be protective of aquatic and terrestrial species.  Estimates
 of  environmental concentrations can be obtained using computerized fate  and
 transport models or simple  mass-balance equations.  The toxicity-based RCs are
 EPA water quality  criteria, or LOELs or NOELs divided by safety factors.

      The  ratio of  the  EEC to the RC for all chemicals are summed to produce a
 hazard index,  and  the  index is compared to predetermined concern levels.  A
 hazard index less  than or equal to 1.0 indicates a low probability of      .
 environmental harm.  A value between 1.0 and 10 is assumed to be indicative of
 possible  effects.   A value  greater than or equal to 10 indicates probable
 environmental harm.  If the hazard index is less than 1.0, the environmental
 impact evaluation  is considered complete.  If the hazard index is greater than
 10, an environmental site evaluation must be conducted.

 5.2.2   Description of  Method

     Receptor Characterization

      Both aquatic  and  terrestrial receptors are considered under  this method.
 Assessments are focussed at the population level, although the value of an
 individual member  of an endangered species is considered by using larger
 safety factors for toxicity values for terrestrial endangered species.  The
 species potentially occurring at a site are identified and differentiated
 based  on  potential differential sensitivity to toxicants.  Toxicity values
 based  on  indicator species  which most closely resemble the sensitivity  of
 potential  receptors are selected for the risk assessment.  Other
 characteristics of potential receptors are not considered.

     Hazard Assessment

     Hazard assessments are conducted at the population  level, and acute  and
 chronic toxicity thresholds are used to calculate RCs; dose-response  data or
 community  and ecosystem level responses are not considered.   For  aquatic
 toxicity,   the reference concentrations are set equal  to  EPA's water  quality
criteria  (WQC).  If a  WQC is not available for a  given chemical,  a  chronic
 LOEL divided by 10, or an acute LOEL divided by  100  (whichever  is lowest),  is
used for hazard assessment.  The factors of 10 and  100 were  derived  from
 statistical and other  analyses of available toxicity  data  and are intended co
 incorporate uncertainties due to test species  sensitivity,  acute  to  chronic

-------
HWT Risk-based Variance            EPA/OSW 1987     •          Page C-55

toxicity extrapolations,  and field to laboratory differences.   If the WQC  for
a given chemical is not relevant for species or  conditions  at  the site,
site-specific criteria can be derived by recalculating a WQC or by conducting
additional tests using water and/or species from the  site.  For terrestrial
species, the lowest of the identified acute NOELs divided by 100 or  the  lowest
of the identified chronic NOEL divided by 10 is  used in the hazard
evaluation.   An additional safety factor of 10  is used when evaluating
potential impacts to endangered species.  The rationale for the terrestrial
safety factors was not provided.

     Exposure Assessment

     Specific procedures for estimating environmental exposure concentrations
are not provided, although procedures ranging from simple mass balance
equations to complex models are proposed.  Exposures via water (for  aquatic
species), and via food (for terrestrial species) are the exposure  pathways
considered.  Procedures used by EPA's Office of Pesticide Programs  (EPA/OPP
1986, Section 4.1) are used to derive exposure doses from exposure
concentrations in terrestrial systems.  Abiotic conditions (e.g.,  pH,
alkalinity, suspended solids, salinity) which may modify aquatic  toxicity are
considered during the exposure assessments.  If site conditions are       /•
sufficiently different from the test conditions under which the toxicity
criteria were derived, site-specific criteria may be developed.

     Risk Characterization

     Risks are estimated by comparing the EEC to the RC  to obtain a ratio.
The ratios are then summed to provide a hazard  index.   If  the hazard index  is
less than or equal to 1.0, a low probability of environmental harm is assumed.
A value between 1.0 and 10 is indicative of possible harmful  effects.  A  value
greater than or equal to 10 is an indication of probable harmful effects.
This approach assumes strict additivity of doses  (i.e.,  similar modes of
toxicity, although chemical potency can vary).  Thus,  antagonistic,
synergistic, or potentiating interactions are not  considered.

5.2.3  Operational Resource Requirements

     The level of effort required for this  approach  should be low to moderate
for chemicals for which toxicity information already exists.   Operational
resource requirements will be much higher  if site-specific criteria are
required.
IFor a given species and chemical,  a  NOEL is  identified as the highest
exposure dose or concentration  tested  that  does not produce an observable
response.  Identification of a  NOEL  requires  identification of a LOEL (lowest-
observed-effect-level) at a higher dose or  concentration.

-------
HWT Risk-based Variance            EPA/OSW 1987                Page  C-56
5.2.4

     The Risk-Based Variance Procedure for evaluating ecological  risks  posed
by Che release of waste constituents from hazardous  waste  tanks  is  a semi-
quantitative risk evaluation approach.  The approach is  similar  to  the
quotient method proposed by Barnthouse et al.  (1986;  Section 7.1.1).  The
primary advantages of this approach are that it is relatively simple to
implement and that it uses data that are readily available for many chemicals.
In addition, this approach considers site characteristics, including receptor
characteristics, when selecting or deriving appropriate  reference
concentrations.  This approach has several limitations,  however.   Many  of
these limitations are inherent weaknesses of the quotient  method; others are
unique to this method:

          The method does not account"for effects of incremental dosages
          (i.e., exposure - response).

          The method does not compensate for differences between laboratory
          and field populations.

          It cannot be used for estimating indirect effects of toxicants,  such
          as food chain interactions.

          It has not been validated and does not quantify uncertainties.

          It does not account for other ecosystem effects (e.g., predator-prey
          relationships, community production/metabolism,  structural shifts,
          etc.).

          Only one exposure pathway is considered for aquatic species  and one
          for terrestrial species.

-------
RCRA Risk-Cost Model              EPA/OSW 1984                Page  C-57

5.3  THE RCRA RISK-COST ANALYSIS MODEL (EPA/OSW 1984)

5.3.1   Introduction

     Subtitle C of RCRA authorizes EPA to develop a national regulatory
program for the management of hazardous wastes.  As part of the regulatory
program, EPA must provide standards for hazardous waste treatment,  storage and
disposal facilities.  The purpose of the RCRA risk-cost analysis model,
developed by IGF Inc., is to provide a consistent method to analyze the
relative risks and costs of different waste management practices.

     Conceptually, the model can be regarded as a three-dimensional matrix,
each cell of which is a combination of a waste stream, an environment,  and a
waste management practice or technology.  The model then calculates the  risks
and costs associated with each waste/environment/technology combination.
Absolute risk values are not calculated in the model, only a relative scale is
used.  Although the model includes modules to assess risks to human health as
well as risks to ecosystems, this summary only addresses the portion of  the
model that assesses ecological risks.

5.3.2  Description of Method

     Receptor Characterization

     Risks to both terrestrial and aquatic (surface water) receptors are
assessed.   The United States is divided into 559 areas based on  three-digit
zip codes.  Each zip code area is defined as having one of seven possible
surface water environments (large, medium, or small river, rivers with large
drainage but low flow, marshes, seacoasts, and lakes).  In addition, the  zip
code area is designated as being "more important" if  it contains a National
park, seashore, wilderness area, monument, river, lake shore or  historic  site,
commercial fishing area, or public or private beach.

     Hazard Assessment

     Although the model addresses the risks associated with waste  streams,  the
hazard assessment is conducted only for the most toxic constituent of the
waste stream.  Toxicity is assessed by constructing  an ecosystem dose-response
curve for the most toxic constituent.  This curve  is  based on  four case
studies where minimal to catastrophic effects were documented.   The  curve
derived from these case studies is shown  in Figure C5-1 and  is  based on  two
assumptions (1) the ecosystem threshold is equal to  the threshold
concentration for the most sensitive species;  (2)  the range  of concentrations
between the threshold and catastrophic level  is  two  to  three  orders  of
magnitude (depending on how "catastrophic" is  defined,  and how carefully the
threshold is measured).  The model's ecosystem damage function varies between
0 (no damage) when the concentration of the pollutant is  at  or below a
threshold and 1.0 (i.e., 100% damage) at  pollutant concentrations  2.5 orders

-------
RCRA Risk-Cose Model
                            EPA/OSW 1984                page c_58
                           FIGURE C5-1
                  THE ECOSYSTEM DAMAGE FUNCTION
                      (Source:  EPA/OSW 1984)

               EXPOSURE-RESPONSE RELATIONS FOR  SPECIES
               AND  DAMAGE FUNCTION FOR ECOSYSTEM a/
                          e '   e *  e' e •     e
           CT V V   V V
      » Ambient chemical concentration in water
      » Exposure-response relation for the  i   species.
      * Threshold concentration for the i   species.
                                                              .ch
D(C)
           • Concentration giving  a  50 percent response rate for the  i
                 species.
           * Concentration giving  a  100 percent response rate for the i
                 species.
           * Damage function for the ecosystem.
           * Threshold concentration for  the ecosystem.
           * Catastrophic or fatal concentration  for the ecosystem
                                                                .th
    a/   Assumes  a given  chemical.

-------
RCRA Risk-Cost Model              EPA/OSW 1984                Page  C-59

of magnitude higher.  The curve is linear with log concentrations.   The  lowest
effect level for an individual organism is defined and used as a surrogate  to
estimate the extent of ecosystem level damages.

     The ecosystem threshold value is derived separately for salt water  and
freshwater aquatic species; subcategories within these receptors are not
addressed.  Hazard to terrestrial systems is assessed by analogy to aquatic
systems because of the lack of appropriate toxicity and exposure data for
terrestrial ecosystems.  For most of the chemicals, the threshold ecosystem
value is chosen as the lowest of either salt water or freshwater species
threshold concentrations.  A different procedure is used for chemicals that
bioconcentrate extensively (e.g., chlordane, hexachlorobenzene, PCB-1254,
toxaphene, and mercury).  For these chemicals, the dose-response curve is
adjusted downward; the catastrophic damage concentration is set by analogy to
the aquatic systems, but the ecosystem threshold is assumed to be 5 orders of
magnitude below the catastrophic concentration on the basis of two case
studies.

     Uncertainty in deriving the aquatic threshold values is addressed by
applying a series of safety factors to the lowest experimental threshold •
values.  The safety factors are based on data quality, data completeness,  .
exposure duration, and the absence of experimental threshold.   The safety1
factors for data completeness vary from 1 to 10 and depend on the quantity and
representativeness of the available data for a given chemical.  If only acute
data are available, empirically derived "acute-chronic ratios" for
structurally similar chemicals are used.  If the lowest concentration at which
a chemical was tested still produced toxic effects, a threshold concentration
is estimated by dividing the lowest effect concentration by 10.  Default
values, based on structurally similar chemicals, are used for chemicals  for
which no data are available.

     Exposure Assessment

     For the aquatic exposure assessment, surface water concentrations  are
estimated with distance downgradient from the point of release.  A  simple
steady-state model is used, based on the release rate of the  chemical,  the
flow rate of the water body, and overall decay rates.  Release  rates  of
chemicals are based on the treatment technology specified and include both
continuous and intermittent releases.  Exposure to terrestrial  systems  is
assumed to be equivalent to the aquatic component  of  the environment, although
insufficient justification is given for this  approach.

     Risk Characterization

     A score is calculated for each cell of  the waste
stream/environment/treatment technology matrix.  The  first  stage score  is
calculated by integrating the aquatic and terrestrial  ecosystem damage
functions over distance downstream from  the  release.   The  first stage score is
the log^Q of the integrated damage.  The  first  stage  scores then are modified
upward by an order of magnitude  if an "important  environment" exists within
the zip-code area.  Aquatic and  terrestrial  scores are  added to obtain the
final score.

-------
RCRA Risk-Cost Model              EPA/OSW 1984                Page C-60


     Although the score is relative, parts of the model,  such as the ecosystem
damage function or the exposure model, could be calibrated and validated.   As
knowledge of ecological effects increase, other damage functions or exposure
models could easily be incorporated into this framework.

5.3.3  Operational Resource Requirements

     The chemical-specific data requirements for this model are low and are
readily available for many chemicals.  The model development effort is
complete, and the model can be run with a relatively low level of skill.  As
the model exists now, the ecosystem component cannot be run separately; a
mainframe computer is needed to run the complete model.

5.3.4  Summary

     The ecological component of the RCRA Risk-Cost Analysis Model scores the
relative risk associated with different treatment technologies, waste streams,
and environments.  One strength of the model is that it is based on empirical
studies of ecosystem responses, yet operates using readily-available data.   It
incorporates a measure of the areal extent of predicted damage  (e.g., stream
miles), and considers the presence of socially or biologically  important
environments.  It is very flexible and could easily be modified to incorporate
findings from recent or future studies.  A limitation of the model is  that
terrestrial risk is assessed almost totally by analogy to the aquatic  system.
Because only the most toxic component of a waste stream is considered,  it
would be difficult to use the model to obtain an absolute estimate of  risk.
However,  components of the model, such as the aquatic hazard assessment, could
be combined with other exposure assessments to estimate absolute  risk  for
individual chemicals.

-------
 Estimating Concern Levels          EPA/OTS 1984               Page  C-61

                6.0  METHODS/ASSESSMENTS DEVELOPED UNDER TSCA

 6.1    ESTIMATING -CONCERN LEVELS" FOR CONCENTRATIONS OF CHEMICAL SUBSTANCES
       IN THE ENVIRONMENT (EPA/OTS 1984)

 6.1.1   Introduction

     The purpose of this method is to provide a framework for calculating
 acceptable release levels of chemicals under the Premanufacturing Notification
 (PMN)  program of the Office of Toxic Substances.  The method can be used to
 identify concentrations of chemicals that might cause adverse environmental
 effects in aquatic populations, and to identify chemicals which should be
 tested more rigorously under Section 5 of TSCA.

     A series of assessment factors are presented to apply to the lowest
 observed effect level of a given chemical.  Guidelines are presented to help
 the assessor choose the appropriate assessment factor, based on the amount and
 type of toxicological data available.

 6.1.2  Description of Method

     Receptor Characterization

     The method has been developed using aquatic toxicity data and is intended
 to predict chronic effects at the population level.  Community effects are
 assumed to mirror individual organism effects.  The proposed approach is
 generic and no specific receptors are identified.  Although temporal
 characteristics of receptors are not included, the assessment factors were
 developed assuming that early life stages are more sensitive than adult life
 stages.  It also was assumed that natural conditions are less conducive to
 survival than laboratory conditions.

     Hazard Assessment

     The concern level is derived by applying an assessment factor to the
 lowest observed effect level for a selected chemical.  The assessment factor
 is chosen to reflect the degree of extrapolation from  the available  toxicity
 data to data needed to assess effects in natural populations; assessment
 factors of 0.1, 0.01, or 0.001 are multiplied by (1)  the lowest chronic effect
 concentration, (2) the lowest LC5Q concentration of many acute  tests, or  (3)
 one LC5Q from an acute test or quantitative structure-activity  relationship,
 respectively.   If there is in situ evidence of population effects  from
biological monitoring or full scale field studies,  the assessment  factor
equals one.   OTS's method of estimating levels of  concern is  intended  to
 identify concentrations of chemicals that, if met  or  exceeded,  might cause
adverse environmental effects in populations at  least  95% of  the  time.   The
possibility that adverse effects might occur below the concern  level is  not
addressed.

     The assessment factors were developed on  the  basis  of  statistical
analysis of laboratory toxicity tests, considering the relationships between
acute and chronic toxicity, laboratory test conditions and  field conditions.

-------
Estimating Concern Levels          EPA/OTS 1984               Page  C-62

and different species sensitivities.  Each assessment factor was  selected  to
approximate a 50% confidence limit.  In other words,  applying the factor to a
given toxicity value (e.g., one acute LC5Q test) should encompass the  toxicity
value of interest (e.g., LC5Q for the most sensitive  species) 50% of the cime.
Toxicity of chemicals that have not been tested can be extrapolated from
appropriate analogs using Quantitative Structure Activity Relationships
(QSARs).

     Exposure Assessment

     An exposure assessment is not included as part of this method.

     Risk Characterization

     The methodology is designed to determine criteria for triggering concern.
It is a quantitative estimation of maximum contaminant levels for individual
chemicals in water that, if met or exceeded, might adversely effect aquatic
organisms.  The method does not consider any toxicity modifying factors or
interactions with other contaminants.  Statistical uncertainty is incorporated
into the assessment factors.  The method could be field validated.
                                                                           :
6.1.3  Operational Resource Requirements

     The method is simple and can be used with a wide variety of chemicals.
The operational costs and effort are inversely proportional  to amount of  data
available for a given chemical.  If little or no input toxicity  data are
available, a high level of expertise on chemical property estimation methods
is necessary.

6.1.4  Summary

     Under this approach, an assessment factor  is applied to available
toxicological data to determine an environmental contaminant concentration
that is likely to result in adverse effects  to  aquatic organisms.   The
strengths of the method are that it is very  simple and that a hazard
assessment can be performed even with very  limited toxicity data.   Limitations
of the method include its failure  to consider  chemical and  biological
interactions, or to use exposure-response data..

-------
 Ecorisk in OTS                    EPA/OTS 1987                 Page C-63

 6.2  ECOLOGICAL RISK ASSESSMENT IN THE OFFICE OF TOXIC SUBSTANCES, PROBLEMS
      AND PROGRESS  (EPA/OTS 1987)

 6.2.1  Introduction

      The  Office of Toxic Substance's Environmental Effects Branch (EEB) has
 developed an approach  for assessing the potential ecological hazards and risks
 associated with new  chemicals.  This approach continues the work of Barnthouse
 e_£  al.  (1982, 1986)  (reviewed in Section 7.1 of this appendix) and also
 previous  work in OTS (reviewed in Section 6.1 of this appendix).  The purpose
 of  the  ecological evaluation is to screen chemicals to identify those for
 which additional testing is needed based on the potential for ecological risk.
 The approach is a modified quotient method in which estimated environmental
 concentrations associated with production, use, and disposal of a chemical are
 compared  to toxicity criteria modified by uncertainty assessment factors.
 Ratios  which exceed  one indicate a potential for ecological impact and thereby
 substantiate the need  for further testing under the New Chemical Review
 Process.

 6.2.2   Description of  Method
                                                                           •.
      Receptor Characterization

      Theoretically,  both aquatic and terrestrial receptors can be considered
 under this  method, but potential impacts to aquatic systems are emphasized
 because the manufacture, use, and disposal of toxic chemicals most often
 results in  discharges  to aquatic environments.  Assessments are focused at the
 population  (species) level, and receptor populations are  selected based on
 their importance as  commercial, sport, recreational, aesthetic or other
 resources valued by  society.  Surrogate species are used  in the quantitative
 evaluations of risk.   Surrogate species are selected based on the general
 laboratory  testing protocol developed by EEB and include  fish, daphnids, and
 algae.  Seasonal or  life-cycle characteristics and niche  characteristics of
 the  receptors are not  considered in the evaluation.

     Hazard Assessment

     Hazard assessments are conducted at the population level,  and  changes in
 growth,  development, mortality and reproduction are identified  as  the
 endpoints of concern.  Two phases of hazard assessments are conducted.   The
 first phase is a conceptual approach in which a fault  tree analysis  is  used  to
 identify ecologically  important impacts on populations  (e.g., Figure C6-1).
 Potential effects on growth, development, reproduction, and mortality  are
 classified as either direct effects or indirect effects (e.g.,  changes  in
 predator prey relationships, competition, habitat).  These are  further divided
 into effects due to natural causes (e.g., climate, normal population
variations) and those  due to toxic chemicals.  Under the  latter category,
acute and chronic effects are considered.  Toxicity modifying factors,  both
biotic (e.g.,  competition) and abiotic (e.g., climate  change)  are considered.
This approach provides a conceptual framework only, and therefore does not
specify  the type of  toxicity data to be used in hazard assessment or the
method by which to derive a hazard value.

-------
Ecorisk in OTS
              EPA/OTS  1987

             FIGURE C6-1
Page C-64
          (Source:
   EXAMPLE OF A FAULT TREE ANALYSIS
Barnthouse eg al.  1986  as  used in EPA/OTS 1987)
                          /    N.     MttMVMV^
                         40MNMTAT.O*   / """V

-------
 Ecorisk  in OTS                    EPA/OTS 1987                 Page C-65


      The second phase of the hazard assessment involves the derivation of a
 "concern level", which is a chemical concentration that if equaled or exceeded
 would justify further testing of a chemical.  Toxicological endpoints are
 defined by the results of acute, chronic, or subchronic tests and are reported
 as  LC5QS, EC5QS, and MATCS.  Toxicity values for the most sensitive species
 are used to determine concern levels.  Concern levels are derived by dividing
 the toxicity value (LC5Q, ££50- or MATC) for a new chemical or an analog by an
 "assessment factor."  Assessment factors range from 1 to 1000 by multiples of
 10, and are based on the degree of uncertainty associated with the toxicity
 values (reviewed in Section 6.1 of this appendix).  An assessment factor of 1
 is used when the toxicity value is based on the results of a field test,  and
 an assessment factor of 1000 is used when there are only two or three
 laboratory tests available for the new chemical or an analog, or if a
 toxicological value is derived from a Quantitative Structure Activity
 Relationship.

      Exposure Assessment

      Specific procedures for exposure assessment are not specified in the
 method, but contaminant concentrations in water resulting from the production,
 use,  or disposal of a particular TSCA chemical must be estimated or measured.

      Risk Characterization

      Environmental concentrations that result or could result from simulated
 or-actual conditions of chemical production, use, and disposal are compared  to
 the "concern level."  Ratios that exceed 1  indicate the potential  for
 ecological impact and justify the need for  further testing.

      Using this approach, the potential for adverse effects  on aquatic
 organisms following exposures to a single chemical via a single  route of
 exposure are evaluated;  multiple chemicals and multiple pathways  are not
 considered.   The method is broadly applicable as a screening methodology  to
 identify areas for further study.  The method, as currently  applied,  does  not
 address uncertainty in the exposure or risk estimate.  Uncertainty in the
hazard assessment is addressed via the use  of assessment factors.   The method
has not been validated, field-tested, or calibrated.

 6.2.3  Operational Resource Requirements

     The resource requirements of the EEB risk assessment  method are low.   The
approach is relatively simple to implement  and requires  minimal  data, most of
which is usually readily available for the  chemical being  evaluated or  an
analog.

6.2.4  Summary

     The method currently used by EEB for identifying  chemicals  for further
study is a modified quotient method.  The primary advantages of this approach
are that it is easy to implement and has minimal  data  requirements.
Consequently, it is an approach useful  for  the  rapid screening of new

-------
Ecorisk in OTS                    EPA/OTS 1987                 Page C-66

chemicals.  There are, however,  several limitations associated with this
approach, and most of these limitations are inherent limitations of the
quotient method:  it does not routinely take into account exposure-response;
it does not consider indirect effects;  it has no predictive capabilities;  and
it addresses the uncertainty associated with variation in taxonomic and life-
stage sensitivities with generic application factors rather than factors
derived specifically for a chemical group or for species in specific regions.

     EEB has recognized these deficiencies and has suggested additional
approaches for consideration in ecological assessments.  The goal of EEB is to
be able to assess both direct and indirect effects, and eventually to evaluate
potential for recovery.  The Ecosystem Uncertainty Analysis (EUA) of
Barnthouse e_£ al. (1982, 1986; see Section 7.1) is regarded by EEB as a
potential tool for evaluating the potential impacts of indirect toxic effects
(e.g., on other trophic levels)  as well as direct toxic actions on
populations.  The model used to illustrate the EUA methodology, SWACOM,
attempts to predict the effects of a toxicant on a pond ecosystem.  Included
in the assessment are estimates of direct mortality and indirect changes in
population, community, and ecosystem structure.  The Risk Analysis and
Management Alternatives (RAMAS)  approach is regarded as a potentially viable
method of addressing the effects of a toxicant on the  age/size class of any.
population.  RAMAS estimates direct toxic action on the life  stages of various
populations by the use of a Monte Carlo simulation of  age structured
populations.  It is designed to address the probability that  a population  will
fall below a given threshold within a specified time,  and also predicts the
number of individuals within a given age class.  EEB is currently  evaluating
the potential utility of these and other methods.

-------
 Users  Manual  for Eco. Risk    Bartithouse et al.  1982,  1986    Page C-67

                       7.0  OTHER METHODS/ASSESSMENTS

 7.1 USERS MANUAL FOR ECOLOGICAL RISK ASSESSMENT (Barnthouse et al. 1982,
     1986)

 7.1.1  THE  QUOTIENT METHOD

 7.1.1.1    Introduction

     The quotient method (QM) (Barnthouse et al. 1986) compares an estimated
 environmental concentration (EEC) to a toxicological benchmark (e.g.,  LC50,
 GMATC, EPA AWQC).  The purpose is either to (1)  predict if an EEC is of
 concern, or (2) rank a series of contaminants or contaminant sources by their
 potential  for producing adverse environmental effects.  The procedures were
 developed  to support EPA's synfuels research program.

 7.1.1.2    Description of Method

     Receptor Characterization

     The type of receptor selected under this approach depends on the type of
 benchmark  value used.  The same type of toxicological benchmark (e.g., MATC'or
 LC50)  is required for all chemicals to make comparisons between quotients.
 Moreover,  a single representative benchmark value is required for each
 chemical.  This value could be the toxicological benchmark value for either an
 indicator  or sensitive species.  Alternatively,  a composite benchmark such as
 an Ambient Water Quality Criterion, designed to be protective of the majority
 of aquatic species, could be utilized.

     In general, toxicological benchmarks (TBs)  for aquatic indicator species
 (population level) are used, but TBs for terrestrial species are available for
 some types of exposure routes.  The approach is usually generic, but a small
 degree of  specificity can be introduced by the selection of appropriate
 indicator  species.  If exposures are expected to be brief, on the  order of
 days, either adult or sensitive life-stage benchmarks could be used as the
 season dictates.  For chronic exposures, LCls or MATC benchmarks are most
 appropriate.

     Hazard Assessment

     There are two statistical types of toxicological benchmarks:  (1)  those
 that prescribe an effect level (e.g. LC50 or LCI) based on a dose-response
 relationship,  and (2) those that are based on hypothesis  testing.  The second
 type of benchmark is exemplified by the MATC which  is assumed  to  lie between a
 no-observed-effect level (NOEL) and a lowest-observed-effect level (LOEL).   To
 identify NOELs and LOELs, responses at exposure concentrations  are compared
with control responses (no exposure) to test the null hypothesis  that  they  are
 the same as the control responses.  Using conventional hypothesis  testing
procedures that set alpha - 0.05 and leave beta unconstrained,  one avoids
declaring  that a concentration is toxic when it is  not with  a  high degree of
certainty  (type I error).  However, there is an undefined chance  of declaring
 that a concentration is not toxic when it is (type  II error).   Thus.

-------
Users Manual for Eco. Risk    Barnthouse e_£ aj..  1982,  1986    Page C-68

coxicological benchmarks based on dose-response  relationships are preferable
to those obtained by hypothesis testing.

     If the quotient method is used primarily as a screening tool to rank
chemicals according to their potential for adverse environmental effects, the
quotients are compared directly.   If the QM is used to provide  an estimate of
environmental risk, uncertainty about the relationship of the TB to  the
organisms and exposure situation at hand is treated by the  application of
safety factors.  Recently, application of a string of safety factors, each
representing a different source of uncertainty,  has become  common.   The
underlying belief appears to be that "everything will go wrong  at once", and
the result can be an extremely conservative evaluation.

     Exposure Assessment

     This method does not include arr exposure assessment.

     Risk Characterization

     "Risk" is based on the ratio of the EEC to the appropriate toxicological
criterion.  For single chemical assessments, concern levels have been set
arbitrarily as follows: no concern, quotient < 0.1; possible concern,  0.1  <
quotient < 10; probable concern,  quotient > 10.  For multiple  contaminant
screening, the quotients are ranked relative to one another.

7.1.1.3  Operational Resource Requirements

     Computationally, the quotient method is extremely simple.   However, the
data requirements can be extensive depending on the benchmarks and chemicals
under consideration.

7.1.1.4  Summary

     The quotient method  (QM) can help  identify EECs  that  are unlikely  to be
of concern.  When the EEC exceeds the lowest  toxicological benchmark
concentration, the QM cannot predict  the degree or  type  of potential
environmental impacts.  The method does not  lend  itself  to consideration of
multiple routes of exposure, food chains, or  any  estimates of  uncertainty.

     The QM is useful mostly as an initial  screening tool.  With appropriate
professional judgment, the QM could provide  a useful method of identifying
contaminants that are below levels of possible  concern.   If a  few  contaminants
must be selected to  represent the waste stream  of a particular source category
in more extensive ecological risk modeling,  the QM can provide a useful first
tier screen.  Even this limited application,  however,  can produce  misleading
results if the quality of information available for the contaminants  is
variable, or if the  slope of  the dose-response  curve differs drastically
between chemicals.

-------
 Users Manual  for Eco. Risk    Barnthouse e_£ al. 1982,  1986    Page C-69

 7.1.2  ANALYSIS OF EXTRAPOLATION ERROR

 7.1.2.1  Introduction

      The  analysis  of extrapolation error (AEE) is a method for estimating the
 probability that an environmental contaminant concentration (EEC) exceeds
 measured  or unmeasured toxicological benchmark values (TBVs).   Unmeasured TBVs
 are  extrapolated from .available information.  The uncertainty associated with
 the  extrapolation  is quantified through regression analysis rather than by the
 application of safety factors.  The AEE method emphasizes that uncertainty in
 estimations contributes to risk.

 7.1.2.2  Description of Method

      Receptor Characterization

      The  AEE provides a methodology for estimating unmeasured toxicological
 benchmarks.  As a  consequence, receptor characterization is far more flexible
 than with the previously discussed quotient method.  The most extensive
 toxicological data  available to support statistical regression analyses are
 for  aquatic species.  For short-term exposure scenarios, toxicological     .
 endpoints  for adults or sensitive life stages can be chosen according  to the
 seasonality of the  anticipated exposure.  For chronic exposures, maximum
 allowable  toxicant  concentrations (MATCs) or LCls are more appropriate.

      Hazard Assessment

      In the absence of appropriate laboratory test data for a species  and
 toxicological benchmark of interest, the benchmarks are extrapolated from
 available  toxicity  data using regression analysis.  The AEE hazard assessment
 consists  of four steps:  (1) definition of the endpoint for the  risk
 assessment in terms of a toxicological endpoint (e.g., the probability of
 exceeding  the brook trout MATC); (2) identification of the existing datum most
 closely related to  the endpoint (e.g. a rainbow trout 96 hr LC50); (3)
 identification of  the necessary extrapolations (e.g. rainbow  trout to  brook
 trout,  96 hr LC50  to MATC); and (4) the statistical regression analysis.

      In step four, an errors-in-variables regression model provides the  best
 estimate of the unmeasured assessment endpoint from the available data.  The
 variance of a single predicted Y-value for a given X-value  is  the appropriate
 value to use in calculating confidence intervals.  The  interest  is in  the
 uncertainty concerning an individual future observation of Y,  such as  toxic
 threshold, for an untested species-chemical combination.   If  more than one
 extrapolation is required, the Y-value from the first extrapolation becomes
 the X-variable in  the second extrapolation.

     The variance  is equal to the sum of the variances  from the  individual
 extrapolations.   The variance associated with  the extrapolation would  depend
 in part on variation in the real world, e.g.,  inter-species differences.   The
variance would also reflect the number of measured data points available for
 the extrapolation.  Thus, the variance associated with  the  extrapolation would
be higher with less well-characterized relationships.

-------
 Users Manual for Eco. Risk    Barnthouse e_t aj,.  1982,  1986     Page  C-70


     Barnthouse and associates validated the double extrapolation method  for
 estimating an MATC of one aquatic species from the acute LC50 of another  where
 laboratory data permitted.  They found that the predictions based on the  AEE
 method were more accurate than the application of generic safety factors.   The
 major advantage of the AEE is that the uncertainty of each estimate is
 quantified.

     Exposure Assessment

     Use of the AEE method presupposes that an exposure assessment  has  already
 been performed.

     Risk Characterization

     The AEE method defines ecological risk as the probability that the ECC
 exceeds the toxicity benchmark value (TBV).  Assuming that the ECC  and TBV are
 independent and log-normally distributed, then:  Risk - Prob(logCTBV) -
 log(ECC)  < 0).  Figure C7-1 illustrates this risk as the shaded area of
 overlap of the ECC and MATC probability distributions.  Thus, the AEE method
 can incorporate both the uncertainty in the value of the toxicological     ••
 endpoint and the uncertainty in the estimate of environmental concentrations.
                                                                           v
 7.1.2.3   Operational Resource Requirements

     The AEE method makes maximal use of available toxicological data to
 estimate unmeasured toxicological benchmarks and/or to estimate  the
 uncertainty associated with either measured or unmeasured TBVs.   If a user is
 interested in a particular extrapolation for which a regression  analysis has
 already been performed with a reasonably up-to-date toxicological data base,
 little computational effort is required to complete an AEE assessment.   If a
 user intends to make a novel extrapolation, an extensive literature search and
 review is required, followed by a moderate computational effort.

 7.1.2.4  Summary

     The AEE, like the quotient method, is best suited  for  answering the
 question "is there a high probability of concern  or not".   It does  not
 estimate the magnitude of ecological effects expected  in situations  in which
 the EEC exceeds the toxicological benchmark.

     This technique could also be used  for ranking the  potential ecological
 risk posed by a series of chemicals.  The estimates of  uncertainty associated
with each TB would help identify which  ratios  of  EEC/TB are significantly
 lower or higher than others.

     Compared with the quotient method,  the AEE has  the advantage  of defining
 and quantifying the terms of an extrapolation  using a large amount of
 toxicological data.  Measurement of  the variability in species'  sensitivity  to
 toxicants and in the relationship of various  toxicological benchmarks to each
 other provides an estimate of the uncertainty  associated with unmeasured

-------
                    p
                    ro
 FREQUENCY


P           O
p
o>
o
O

o
m
5
t>
                  (A £

                  O


                  M
                  O

                  »
DO
P>

3
r»

|

(A
»
                  |o> ba
                  Irt M



                  ^

                  *-* D
                  vO M
                  00 M
                   H
                                                O
                                                «J
                                                i
        M

        »

        M

        U
                                                                                    I
                                                                                    p]
                                                                                    o
                                                                                    o
                                                                                    po
                                                                                    H-
                                                                                    W
                          09
                          P>
                                                                                    rt
                                                                                    ET
                                                                                    O
                          fc
                                                                                    vO

                                                                                    00
                                                                                    OO
                                                                                    P>

                                                                                    00
                                                                                    A


                                                                                    O

-------
 Users  Manual  for  Eco. Risk    Barnthouse et al. 1982,  1986    Page C-72

 coxicological benchmarks.  The explicit estimation of uncertainty should
 assign higher probabilities of adverse effects for chemicals which are less
 we11-characterized.

 7.1.3   EXTRAPOLATION OF  POPULATION RESPONSES

 7.1.3.1  Introduction

     The  purpose  of  the  extrapolation of population responses (EPR) method is
 to extrapolate  from  individual-level responses in laboratory settings to
 population-level  responses in the field.  The EPR method first develops life-
 stage-specific  exposure-response functions for a single species.  These form
 the basis for estimating changes in a population's reproductive potential with
 toxicant  concentration as well as the confidence limits of the relationship.

 7.1.3.2  Description of  Method

     Receptor Characterization

     Application  of  the  EPR method requires a life-stage characterization of a
 receptor  population.  Barnthouse et al. (1986) developed an example for a fish
 population in which  all  life stages are exposed through the same medium.  The
 number  of life  stages is variable, depending on the organism and the quality
 of data available for each stage.  A life table including the following
 information is  required  for each age after the first breeding year: the
 proportion of mature females, the fecundity per mature female, and the
 cumulative probability of survival from the age of reproductive maturity to
 each future age.

     Hazard Assessment

     The  life-stage-specific concentration- or exposure-response  functions
 form the  backbone of the EPR method.  Exposure-response data sets  can be
 fitted  to  a logistic equation using nonlinear  least squares regression.    The
 confidence limits (uncertainty band around the fitted regression)  can be
 estimated from  the elements of the variance-covariance matrix.   Because  full
 life-cycle exposure-response data are rarely available, extrapolation  from the
 few well  studied  species will often be necessary.

     Barnthouse ejj a\. (1986) used the analysis of extrapolation error  (AEE)
method  to  estimate the chronic LC25 and one of the exponential  parameters  for
exposure-response functions for 60 species/contaminant/experimental  condition
combinations.  The extrapolated response  functions and the  uncertainty  bands
were verified for the 60 data sets with favorable  results.

     Exposure Assessment

     This  method  presupposes an exposure  assessment.

-------
Users Manual for Eco. Risk    Barnthouse et a^.  1982,  1986     Page C-73
     Risk Characterization

     The endpoint considered for the risk assessment in the  Barnthouse et al.
(1986) example was the reproductive potential of a female recruit  into a fish
population.  Lifetime reproductive potential is dependent on the probability
of survival to successive life stages and age-specific fecundity.   From the
exposure-response curves developed for each life stage, the  probability of
survival from one age to the next is estimated.  Finally, the exposure -
response function for reproductive potential is constructed  using  a log-probit
model.  The appropriate confidence limits are used to define a band of
uncertainty around the exposure-response function as illustrated in Figure
C7-2.  Barnthouse et. al. (1986) found narrow confidence limits associated with
between species extrapolations and large confidence limits in situations where
chronic benchmarks were extrapolated from acute values.

     The final step is estimating the probability of various effect levels
given an environmental concentration.  Barnthouse e_£ al. (1986) did not
elaborate on this point.  From Figure C7-2, it is clear that the most simple
approach would be to define concentration levels of no concern, intermediate
concern, or serious concern.  Alternatively, one could define the probability
of exceeding a certain percentage reduction of female reproductive potential.

7.1.3.3  Operational Resource Requirements

     If full life-cycle exposure-response data are not available for a species
of interest, the function could be extrapolated from information on other
species.  The degree of effort would be entirely dependent on the number of
extrapolations required.  Barnthouse et al. (1986) have compiled and presented
a large body of freshwater fish acute and chronic toxicity test information.
A computer software statistical package is required for  fitting experimental
data to log-probit regressions.  The remaining computations  require a moderate
amount of computer assistance.

7.1.3.4  Summary

     The extrapolation of population responses  (EPR) method  is very similar co
simple analysis of extrapolation error with two possible  improvements.  The
EPR method combines information from several life stages  into  a single effect
level, thus offering the potential for a more  accurate representation.
Second, a variety of effect levels can be  considered  as  endpoints.

     The EPR methodology provides several  advantages  over the  use  of MATCs  for
setting regulatory standards for water criteria.  Barnthouse et al.  have
pointed out that the use of hypothesis testing to estimate  MATCs  leads to
nonconservative risk assessments.  The probability  of committing  type  II error
(i.e., accepting a concentration level as  non-toxic.when it is in fact  toxic)
is unconstrained.  The less rigorously the  experiment is conducted (smaller
sample sizes or poor control of other environmental factors),  the higher  a
concentration will have to be  to produce response  levels that are
significantly different from control  levels.   With  the EPR  method, Barnthouse
e_t al. estimated LC^QS for several  species  that were  an order of magnitude

-------
Users Manual for Eco. Risk
Barnthouse e£



  FIGURE C7-2
1982, 1986
                                           Page C-74
               PERCENT RESPONSE VS. CONCENTRATION

               (Source:  Barnthouse g£ al. 1986)
  01
  00



  1
  00
  LU
  GC
  UJ

  O

  cc
  UJ
                                UNCERTAINTY

                                BAND
                  CONCENTRATION

-------
 Users  Manual  for  Eco. Risk    Barnthouse §_£ aJL. 1982, 1986    Page C-75

 lower  than the  estimated MATCs.  For example, che brook trout MATC for
 methylmercury (0.53 ug/liter) corresponds to a 60 to 78 percent reduction in
 reproductive  potential  in brook trout according to the EPR method.

     A limitation of this type of model, however, is that a large amount of
 the  toxicant-induced mortality that affects female reproductive potential
 occurs in  the young, pre-reproductive age-classes.  If recruitment into the
 breeding population in  free-living populations is in part density-dependent, a
 given  percentage  death  in a pre-reproductive cohort might have a much smaller
 percentage  effect on recruitment into the breeding population.

 7.1.4   ECOSYSTEM  UNCERTAINTY ANALYSIS

 7.1.4.1  Introduction

     The ecosystem uncertainty analysis (EUA) method attempts to  extrapolate
 from single species toxicity effects to ecosystem level effects.  In
 particular, the model attempts to address higher order effects for
 concentrations  that are well below acute LC^Q values.  The EUA emphasizes the
 uncertainty associated with each level of extrapolation.  In principle, any
 sort of model of  biotic community relationships could be used.  The key
 feature of  the uncertainty analysis is the use of simulation techniques and
 probability distributions for underlying parameters to generate probability
 distributions for effects.

 7.1.4.2  Description of Method

     Receptor Characterization

     Receptor characterization depends upon the actual "ecosystem" model used.
 As an  example, Barnthouse et al. (1986) used the Standard Water Column Model
 (SWACOM).   SWACOM is a computer model designed to simulate the pelagic
 portions of a north temperate lake ecosystem.  The model, illustrated in
 Figure C7-3,  includes ten phytoplankton populations, five zooplankton
 populations,  three planktivorous fish populations, and a top carnivore
 population.   The  populations within each trophic level may have differing
 sensitivities to  toxicants.  Seasonal variation  in abiotic factors constrain
 the seasonal  behavior of the populations and their relationships.

     Hazard Assessment

     SWACOM model parameters include processes such  as grazing,  respiration,
 and susceptibility to predation.  The expected change  in each  parameter  value
 in response to exposure to a given toxicant concentration  is  expressed by  an
 element of  an effects matrix.  For each of the effects  in  the  matrix, an
 estimation  of uncertainty is required.  The uncertainty can  either be measured
 from appropriate  data or estimated based on professional judgment.   Usually,
however, the  appropriate data are not available  for  the  parameters used by
 SWACOM.

-------
Users Manual  for Eco. Risk    Barnthouse et aj.. 1982,  1986

                                FIGURE C7-3


                         THE SWACQtf GOHFOTER MODEL
                     (Source:   Barnthouse et al. 1986)
Page C-76
                                   PREDATI
             TEMPERATURE
   0         360
        DAYS
                                                     NUTRIENTS
                                                          36O
                                                                   LIGHT
                                                     FORAGE
                                                     FISH
                                                            SEDATION.
                                                                       CARMVO
                                                                       ROUS FIS

-------
Users Manual for Eco. Risk    Barnthouse gt aJL.  1982,  1986    Page C-77

     To circumvent the lack of data relating toxicant concentrations  to  the
parameters used by the SWACOM model, Barnthouse and associates suggested using
a  "general stress syndrome" to depict each population's response to sublethal
toxicant concentrations.  For example, a general stress response by grazing
fish might include decreased respiration, lower temperature optima, and
increased mortality and susceptibility to predation.  To extrapolate  from
acute toxicity LC5Q values to effects on respiration,  susceptibility to
predation, etc., Barnthouse eg aj.. (1986) assumed that (1) organisms respond
to all toxicants in a uniform manner, and (2) all parameters (e.g.,
respiration, susceptibility to predation) are changed by the same percentage
in response to a toxicant exposure.

     This extrapolation is extremely tenuous and does not lend itself to an
analysis of uncertainty.  It is necessary to know not only the percentage
change in parameters, but also the uncertainty to be associated with the
change.   Barnthouse e_t al. (1986) assumed that "all parameter changes have  an
associated uncertainty of plus or minus 100%."

     Exposure Assessment

     This aspect of modeling was not addressed.

     Risk Characterization

     The endpoints of EUA analysis are operationally defined in terms of
"effects variables".  These must be predetermined and might include effects
such as a 25% decrease in game fish biomass or a 50% increase in  algal
biomass.

     SWACOM simulates the population dynamics of the phytoplankton,
zooplankton, grazing fish, and one top carnivore.   Competition among species
within a trophic level, and predation or grazing by higher trophic levels on
lower trophic levels, are modeled.  In addition, an annual cycle  of nutrient
flux, light, and temperature affect growth and reproduction.  Environmental
concentrations are compared to the effects matrix for each species and  each
parameter to determine the direction and magnitude  of the effect.

     The ecosystem is then modeled using a Monte Carlo simulation.  At  the
start of each run, parameter values are drawn from  their  statistical
distributions.   In this way, uncertainties are propagated through the model
ecosystem.  The simulation continues until a stable frequency distribution  of
results is obtained.  In this way, the uncertainties of extrapolating
laboratory data to the field should become statements  about  the  uncertainty of
an undesirable effect.  Thus, the risk of a specified  adverse effect  level  is
a function of both of direct toxicity and the effect of uncertainty  resulting
from the extrapolation.

     The ecosystem effects calculated by EUA could  not be predicted without
this form of analysis.  For example,  increasing bluegreen algal blooms  with
increasing toxicant concentration appears counterintuitive.   The SWACOM
adaptation,  however, indicated that even though a compound may  be toxic to  the

-------
Users Manual for Eco. Risk    Barnthouse e_t al.  1982,  1986     Page  C-78

algae, reduction in sensitive grazing organisms  can more than compensate  for
the adverse direct effects on phytoplankton.

7.1.4.3  Operational Resource Requirements

     In general, the data requirements for ecological uncertainty analysis  are
large.  First, a reasonably large number of receptor populations are required
to simulate a microcosm.  Second, exposure-response data, mechanisms of
action, and sublethal toxicant effects are required for reasonably realistic
modeling efforts using a model such as SWACOM.  Finally, a large number of
input parameter distributions must be obtained or estimated.

     To preserve the influence of the uncertainty in the input parameter
distributions, Monte Carlo simulation techniques are most appropriate.  The
number of iterations of the model required to generate a reasonably stable
output distribution can in theory be-quite high.

7.1.4.4  Summary

     The compromises that are needed to implement a model like SWACOM reflect
a fundamental shortcoming in available data.  Some of the more realistic
options for modeling the effects of toxicants at population  and community
levels require far more information on sublethal effects than simple acute
toxicity or even chronic toxicity testing  typically provide.  To the extent
that models like SWACOM are scientifically verified  (e.g., scientifically
reasonable), the need for qualitatively different  toxicological data  is
apparent.  The alternative solution is to  use models  that use mortality  as  an
endpoint, as does the CERCLA Type A Assessment Model  (DOI 1987a).

-------
             Regional  Ecological Assessments   Ballou et al. 1981          Page C-79


             7.2  REGIONAL ECOLOGICAL ASSESSMENTS:  CONCEPTS, PROCEDURE AND APPLICATIONS
                  (Ballou e£ ai. 1981)

                  Argonne  National Laboratory (ANL) developed several approaches for
             conducting  regional assessments of the potential ecological impact of energy-
             development activities.  Some of the primary approaches proposed include (1)  a
             regional  ecological characterization scheme, (2) procedures for estimating
             crops and natural vegetation at risk from gaseous pollutants, (3) procedures
             for estimating crop yield reductions, (4) procedures for estimating and
             quantifying direct land disturbance, (5) a data base and mapping procedure for
             predicting  overlap with endangered or threatened species habitat, and (6) the
             use of ecosystem resiliency and diversity as a tool for ecological assessment.
             The scope of  the project focused primarily on energy impacts in the Midwestern
             United States.

                  Below,  each of these approaches is discussed in the context of its
             usefulness  for ecological risk assessments.

             7.2.1 REGIONAL ECOLOGICAL ASSESSMENT UNITS

             7.2.1.1   Introduction

                  ANL  developed an ecological receptor characterization scheme based  on
             regional  physiographic units.  This classification  scheme reflects regional
             homogeneity of environmental variables, and thus is based on ecologically
             meaningful  characteristics.  Such a classification  scheme facilitates
             generalizations regarding the impacts of energy-related or other  activities on
             regionally-homogeneous ecological areas.

             7.2.1.2   Description of Method

                  Receptor Characterization

                  ANL  categorized the terrestrial environment into  approximately  90
             "ecological assessment units (EAUs)" defined by commonalities  of
             bedrock/substrate, landform, soils, natural vegetation, and  land use (e.g.
             Piedmont  lowland, unglaciated Allegheny plateau).   The EAUs  were built  from  an
             existing  national classification system based  on climate,  soils,  and
             topography.   EAUs were derived from physiographic units that were
             statistically homogeneous according to land use and cover  type.   Within each
             of  the EAUs,  ANL developed a county-specific data base that  included the
             generalized land-use characteristics  (e.g. pasture,  cropland)  and potential
             natural vegetation (e.g. maple-basswood forest, oak savannah),  and the  percent
f             cover  for each county by these categories.

             7.2.1.3   Operational Resource Requirements
,*
                 This approach for receptor characterization  is based on readily available
             information.   The initial data gathering and compilation  would be resource-
             intensive.  However, because the initial collection and compilation has been

-------
Regional Ecological Assessments   Ballou et  al.  1981          Page C-80

completed by ANL, application of this  approach  should be inexpensive and
require minimal individual expertise and effort.

7.2.1.4  Summary

     The major advantage of the EAU approach for receptor characterization is
that large-scale energy activities or other  large-scale ecological stresses
can be related to broad, ecologically similar regions.  For  example, the
Adirondack Mountains, Allegheny Mountains, and  Superior Uplands  are  each
physiographic units that are highly sensitive to acid rain deposition because
they are characterized by bedrock and soils  with low buffering capacities due
to a lack of base minerals. Based on similar interpretations of  common
characteristics among EAUs, potential impacts to related ecosystems  can be
estimated.  This approach is for receptor characterization only,  and must be
combined with hazard and exposure information for use in ecological  risk
assessments.

7.2.2  DETERMINATION OF CROPS AT RISK AND ESTIMATING CROP YIELD  REDUCTIONS

7.2.2.1  Introduction

     One of the major potential impacts of fossil-fuel  burning plants  is
reduced crop yield and damage to both agricultural and  natural vegetation from
elevated sulfur dioxide (SC^) levels.  ANL used reported exposure-response
data derived from energy technology assessments to identify  species  of crops
and natural vegetation types at risk from future releases  of S02.  Also,
exposure-response data were combined with model-based estimates  of exposure to
determine crop yield reductions from estimated releases.   Yield reductions
were determined for both acute and chronic exposure scenarios.  The risk of
significant crop yield reduction (i.e., > 5%) was determined by the number of
concentration threshold exceedances.

7.2.2.2  Description of Method

     Receptor Characterization

     ANL identified the dominant crop  species and natural vegetation species
within each county of the U.S.  Crop data by county was obtained from the 1974
Census of Agriculture.  Information on natural vegetation communities was
derived vising Kuchler's (1974) classification of vegetative  communities  in  Che
U.S. (Am. Gco. Soc. Sp. Pub. No. 36).   Dominant vegetative  species  were
assumed to be representative of other  vegetation within the  community.   Only
terrestrial species were considered in the  classification.   The  most
susceptible stage of growth  for each species was  identified.

     Hazard Assessment

     The hazard assessment consists of two  phases:  a  screening phase in which
available toxicological data are used  to determine  the relative sensitivities
of the various dominant vegetation types to S02,  and a more detailed
assessment phase in which  available  toxicological  data are  used in a
quantitative determination of  crop-specific effect  levels.   The screening

-------
 Regional Ecological Assessments   Ballou et al. 1981          Page C-81

 phase is limited  to determination of  impacts following acute, high-level
 exposures.   The more  detailed assessment phase evaluates impacts following
 both acute  and chronic exposures.  Presumably, the most sensitive endpoint was
 used in determining relative species  sensitivities.  Although species-
 specific data are used,  the results of the assessment are assumed to be
 representative of potential community impacts.  There is no treatment of
 uncertainty in the hazard assessment.

      In the screening phase, ANL classified 93 of their 116 vegetation
 categories  according  the sensitivity  of the dominant plants to S02-  Plants
 were classified qualitatively as sensitive, intermediate, and resistent.  The
 classification was based on an extensive literature review of the exposure-
 response of a variety of plants to S02-  Average 3 -hour maximum $©2
 concentrations were used to predict impacts on vegetation.

      In the detailed  phase, ANL used 'estimates of short-term peak
 concentrations to determine impacts on crop yield following acute exposures .
 Impacts  following chronic low- level exposure were determined using studies on
 yield reduction in soybeans.  Based on the available literature, a damage
 threshold of 234 ug/nr was determined for soybeans.  Although a hazard
 assessment  for chronic exposures was  conducted for soybeans only, the approach
 of threshold identification can be used for any species for which adequate
 exposure -response data are available.

      Exposure Assessment

      Exposure concentrations were determined for both short-term and  long-term
 releases.   Spatial and temporal variations in exposure concentrations were
 considered  using short-term and long-term dispersion models.  Only exposure
 via  air was  considered.

     Acute  exposures  to SOo.  ANL developed modeling techniques to estimate
 the  peak  ground- level concentrations  of air pollutants near  a point source as
 a function  of power plant capacity and emission rate.  The techniques used
 short-term  mathematical models to provide estimates of 'peak  ground- level
 concentrations and the distances from the source at which they  occur.   In chis
 screening methodology, the critical meteorological conditions under which peak
 concentrations may occur are identified and the corresponding concentrations
 determined.  Thus, the worst case scenarios are modeled and  the ground  surface
 area exposed to various peak SC>2 levels is defined.
                    Air Quality Modeling.  A  slightly  different  air  quality
modeling approach was used to estimate doses  following long-term,  low- level
pollutant exposure.  Under this approach,  the total  number  of multiple-hour
exposure periods in which a given  threshold concentration is  exceeded is
determined.  For the purposes of cheir assessment  of soybean  yield loss,  ANL
chose a threshold value of 234 ug/nr  for  a 4-hour  exposure  period based on
empirical data.  A Gaussian dispersion model  was used  to determine exposure
concentrations.  Total dose was determined by summing  the total  accumulated
dose for each 4-hour period in which  the  threshold value was  exceeded.
Spatial contours of the total SC>2  dose were developed.

-------
Regional Ecological Assessments    Ballou et al. 1981          Page C-82

     Risk Characterization

     The contours of the total  S02 dose determined in the exposure assessment
are used to estimate the risk of significant crop yield reduction by comparing
estimated concentrations with available crop dose-response information.

     Under this quantitative  approach, only potential damage  to a single crop
species following exposures to  a single compound via a single route of
exposure are evaluated.   There  is no treatment  of uncertainty.  The approach
has been partially validated by comparing  modeling results with empirical
data, and the results were in good agreement.   The approach  is flexible, so
that if sufficient dose-response information is available, it can be applied
to similar situations to determine potential damage from  airborne pollutants
to other plant species.

7.2.2.3  Operational Resource Requirements

     This approach is expensive and labor-intensive.  Large  amounts of data
must be compiled to determine dominant species  within counties or other
designated regions, and to determine dose-response relationships  for each
species and each chemical evaluated.  Additional expertise and costs are
associated with the air modeling effort.   The  costs and  level of  skill
associated with interpretation  of the available data  are  moderate.

7.2.2.4

     The procedure for crop loss assessment proposed by  ANL  is  a quantitative
worst-case approach to estimating the areal extent of significant crop yield
reduction (i.e., in excess of 5 percent)  from emissions  of phytotoxic  gases.
The primary advantages of this  approach are that it  is  flexible  and can be
applied to estimate damage to other plant species  from various  air pollutants.
However, the approach is cost-  and data-intensive,  and its applicability is
limited somewhat by a current lack of dose-response  data for many species and
pollutants.  In addition, only damage co plants is estimated and is assumed to
be representative of damage to the community or ecosystem.

7.2.3  DETERMINATION OF LAND USE DISTURBANCES

7.2.3.1  Introduction

     ANL developed algorithms for quantifying  the amount of  land disturbed by
energy activities.  The proposed methodology determines  the amount of  land
required for power plant sites or for mining,  the amount of  additional land
disturbed by these activities,  and  the significance of the  impacts.   Under
this approach, the amount of forest, grassland, or other natural habitat
disturbed is of greatest concern  for ecological assessments.  Impacts from  a
number of processes are considered,  including  building,  moving soil,  noise,
human presence, road construction,  and traffic.

     The endpoint of concern in  this assessment is loss  of  land  use.   The
stresses in this assessment are  direct and indirect physical stresses (e.g.,
land destruction (direct), human  presence and  noise  (indirect))  rather than

-------
Regional Ecological Assessments   Ballou et al. 1981          Page C-83

chemical, and therefore hazard assessments as typically conceived are  not
appropriate.  Exposure assessment determines the amount of overlap of  the
physical disturbances with the land.  "Risk" in the context of this approach
is not a determination of the probability of an effect level,  but rather an
estimate of damage (land usage loss).

     Below, we discuss the aspects of this approach that are applicable  to
risk assessment.

7.2.3.2  Description of Method

     Receptor Characterization

     The receptor under this approach is land, and land is differentiated  by
land use.  Land use categories include crop land, pasture, range, forest,
urban land, Federally-owned land, and-other rural land (e.g.,  roads, farm
buildings, swamps, and barren land).' It was assumed that Federal land is
covered by natural vegetation, and that very little urban land remains in  its
natural state.  Land use was determined on a county basis, and is therefore
relatively site-specific.

     Exposure Assessment                                                   •.'

     As mentioned above, exposure assessment is limited to a determination of
the overlap of physical disturbances with land.  Areas of directly disturbed
land are determined on the basis of a step function using average values
reported in the literature for particular technologies and generating
capacities.  In this way, basic site requirements for power plants and mines
are determined.

     Risk Characterization

     Two approaches are used.  The first approach is quantitative  and equates
damage with land loss.  The second is qualitative and attempts to  interpret
the effects of land loss on the affected species.  Under  this qualitative
approach, species expected to occur in a particular land  type are  identified,
and the habitat requirements for these species are outlined.  Land use
disturbance is interpreted in the context of loss of habitat  requirements.

7.2.3.3  Operational Resource Requirements

     The initial classification of land use  is moderately labor-  and  cost-
intensive.   Determination of airect land loss  requires minimal resources  and
expertise.   Qualitative assessments of potential  impacts  to nonplant  species
requires personnel trained in wildlife biology.

-------
 Regional Ecological Assessments   Ballou et al,  1981          Page C-84


 7.2.3.4  Summary

     This approach is unique among many of the assessment methodologies  in
 that land loss and disturbance are endpoints of concern.   The  approach is
 limited to interpretation of effects associated with physical  disturbances of
 land use; procedures for predicting and quantifying land use  loss  from
 chemical contamination have not yet been developed.

 7.2.4  POTENTIAL IMPACTS TO ENDANGERED AND THREATENED SPECIES

 7.2.4.1  Introduction

     ANL documented the distribution of endangered and threatened  species  and
 their habitats in the Midwest and the-reasons for the declining populations.
 The approach is not an ecological risk assessment in that no  hazard,  exposure,
 or risk assessments are conducted.  The approach does, however, provide  some
 useful concepts for receptor characterization; these are discussed below.

 7.2.4.2  Description of Method

     Receptor Characterization

     ANL conducted an in-depth literature search and consulted state and
 Federal wildlife experts regarding the distribution of threatened and
 endangered species in the Midwest.  Particular emphasis was placed on habicat
 characteristics and habitat requirements in the context of interpreting
 species decline.  Such information is useful in predicting the potential
 response of a species to environmental changes.

     The county-level distribution of designated species was determined.  The
 resulting data base was designed for use as a screening mechanism to identify
 counties where potential conflicts may occur through  the implementation of
 projected energy scenarios.

 7.2.4.3  Operational Resource Requirements

     This approach for receptor characterization is based on readily available
 information.   The initial data collection and compilation is moderately
 resource-intensive and requires some expertise in  the area of  ecology.
However,  once the data are compiled, application of the  approach  should be
 inexpensive.   Interpretation of potential impacts  from environmental
disturbances requires some understanding of ecology.

 7.2.4.4  Summary

     This approach is an easily-implemented,  relatively  low-cost,  qualitative
screening mechanism for evaluating the potential for  damage  Co endangered and
 threatened species.  It does not predict what  effects,  if any, will  occur, but
only estimates the potential for effects.  Counties with more  endangered
species can be assumed to have a greater potential for  detrimental effects.

-------
 Regional Ecological Assessments   Ballou et al.  1981          Page  C-85

 No hazard, exposure, or risk components are incorporated into this  approach;
 it is mainly applicable for receptor characterization and as a screening  tool.

 7.2.5  SPECIES DIVERSITY AS A TOOL IN ECOLOGICAL ASSESSMENTS

 7.2.5.1  Introduction

     ANL proposed a conceptual approach for incorporating ecosystem diversity
 measurements in ecological field assessments.   Species diversity is an
 attribute of all ecosystems, and is often considered a primary indicator  of
 ecosystem "health", stability, and resilience.  Ecosystem resilience is  a
 system's ability to recover without losing its intrinsic identity.   The  more
 resilient a system, the better that system is able to recover from
 environmental perturbations.  Diversity indices can be used as a measure  of
 ecosystem resilience.  Several diversity indices were discussed.

     The diversity approach is a tool for evaluating and monitoring the
 ecological environment.  The approach provides unique concepts for receptor
 characterization, and can be used as a rough screening mechanism for
 estimating ecosystem vulnerability.

 7.2.5.2  Description of Method

             Jlhj^acterigation
     The receptors under this approach are communities and ecosystems.
Communities and ecosystems are defined both temporally and spatially, in
addition to taxonomically .   Abiotic and biotic characteristics of the system
are defined and considered when determining diversity.  Three types of
diversity are defined:  alpha diversity refers to species diversity at a
particular site; beta diversity refers to species diversity among ecologically
similar sites; and gamma diversity refers to species diversity among
ecologically similar and variable sites.  The approach results in a fairly
complete characterization of communities and ecosystems.

7.2.5.3  Operational Resource Requirements

     This approach to receptor characterization is resource- and data-
intensive.  Large amounts of data are needed on species composition,  number,
and distributions within and between systems.  This requires extensive review
of available data, and probably requires additional data gathering  in the
field.  Experienced ecologists would be needed to collect and interpret  the
data.

7.2.5.4  Summary

     This approach characterizes receptors at the community and ecosystem
level.  Abiotic and biotic as well as temporal and spatial aspects  of systems
are considered.  The approach is not a risk assessment  methodology;  it  is  an
environmental monitoring and evaluation technique.  However,  the  diversity of
a system can be used as a relative measure of the potential  for damage
following environmental disturbances.  In this context,  the  approach is  most.

-------
Regional Ecological Assessments   Ballou et al. 1981          Page C-86

appropriately used as a screening tool in ecological assessments.  The
approach, however, is relatively resource-intensive, and this may limit its
usefulness.

-------
Computer Simulation Model     Eschenroeder et al.  1980         Page  C-87


7.3  COMPUTER. SIMULATION MODELS FOR ASSESSMENT OF TOXIC SUBSTANCES
     (Eachanroeder e£ al. 1980)

7.3.1  Introduction

     The computer simulation model described in this document is the  result  of
an exploratory study, funded by the National Science Foundation, to develop  a
model to aid in the assessment of environmental effects of toxic substances.
The model is a series of generalized differential equations based on
bioenergetic parameters.  The equations are used to calculate population
biomass, expressed as biomass/energy equivalents,  and concentrations  of the
chemical in each population.  Lethal and sublethal effects of chemicals can
also be incorporated into the model and the subsequent effects on biomass and
chemical concentration in each population examined.  A simplified example, DDT
in a pond ecosystem, was described in-the document.  In the example,  only
aquatic organisms were modeled, and populations were grouped by trophic level.

7.3.2  Description of Method

     Receptor Characterization

     Although the model could be adapted to simulate many systems,  it is
applied in this document to a simple aquatic community.  The community
consists of one or two species at each trophic level.  Populations  of species
at each trophic level are "lumped" and changes are simulated by each trophic
level.   Species that change trophic levels in their lifetimes (e.g.,  perch,
which become pisciverous with age) are divided, based on biomass,  into
different trophic levels.  Although temporal changes are not incorporated into
this example, the possibility of incorporating it  in future versions of the
model is discussed.

     Hazard Assessment

     Damage functions/expressed in terras of dose, were constructed for rates
of mortality, respiration, and feeding.  The functions were constructed based
on assumed baseline and saturation levels for the  effect of concern, and a
threshold concentration of contaminant eliciting the effect.  Individuals were
then assumed to be normally distributed with respect to the step-function.

     Exposure Assessment

     Exposure is calculated for each compartment,  in this  case,  by trophic
level.   Chemical flux into the producer compartment  is expressed as mass units
of toxic material per kilocalorie of biomass/energy.   Loss  terms from  the
producer compartment include predation, mortality,  and excretion.   At higher
trophic levels, exposure occurs only through the  food  chain.  Thus,  the
chemical concentration in higher trophic  levels  is calculated as the  influx by
feeding minus loss terms including predation, mortality,  and excretion.   The
incorporation of a bioconcentratton factor  from water  into higher  trophic
levels  was discussed as a possibility  for  future  versions of the model.

-------
Computer Simulation Model     Eschenroeder et  al.  1980         Page C-88

     Risk Characterization

     The model uses two sets of differential equations  to  describe population
dynamics and chemical concentration.   In the example,  the  model was  used  to
estimate change in biomass and chemical concentration in a simple aquatic
system by trophic level.  Toxic effects of chemicals  are combined with
exposure (i.e., dose) in the model by constructing injury  functions.  In  this
way, effects of chemical concentrations are fed back  into  the set of
differential equations describing population dynamics.   Risk is  then expressed
as the percent reduction in energy/biomass for each compartment.   In the
simplified version of the model, species were  aggregated and competition  was
ignored, although with sufficient information, these  two issues  could be
incorporated.

     Predictions of residues were roughly validated using  general  information
on DDT levels in different trophic levels of the environment compiled from the
literature.  The model was analyzed for sensitivity to effects at  different
trophic levels, and to variations in the damage functions.  The  model could be
validated using a simple pond mesocosm or microcosm.

7.3.3  Operational Resource Requirements

     The model requires some exposure-response data that are largely
unavailable (e.g., for ingestion) for endpoints that might be difficult to
measure for many systems, (e.g., bioraass, respiration rates, feeding rates).
It requires a high level of effort and skill,  as well as a computer.

7.3.4  Summary

     A major strength of the model is that it is very flexible.   Although the
compartments in the example were trophic  levels, with sufficient information,
compartments could be species or even age or weight class within species.
Stochastic and temporal elements could also be  incorporated.  Sublethal
effects such as feeding rate changes, as  well as mortality,  are included.
Risk is presented as a reduction in bioraass, which could  easily be  input  to
costing models.  Because biomass and residue  concentration were modeled  on  a
time-specific basis, recovery dynamics of the system can  be  examined.  A
limitation of the model is that it uses bioenergetic terms  and units that are
unfamiliar to many people.  Data needs are high,  and with refinement of  the
model, data needs would be even greater.  For this reason,  the model is
presently limited to very simple systems.

-------
 Comparative Risk Project        EPA/OPPE 1987               Page  C-89

 7.4  UNFINISHED BUSINESS:  A COMPARATIVE ASSESSMENT OF ENVIRONMENTAL PROBLEMS.
     APPENDIX III, ECOLOGICAL RISK WORK GROUP (EPA/OPPE 1987)

 7.4.1  Introduction

     The objective of the Comparative Risk Project (CRP) was to estimate  and
 rank current cancer risks, noncancer health risks, welfare effects,  and
 ecological effects presented by 31 major environmental problem areas which  EPA
 has some responsibility and authority to control; the purpose  was to establish
 program and budget priorities.  Separate workgroups were formed to evaluate
 each type of risk; this summary addresses only the ecological  risks component
 evaluated by the Ecological Risk Work Group (ERVG), which was  assisted by an
 expert panel convened by the Cornell Ecosystems Research Center.

     The objective of the ERWG was to rank the relative ecological risks,
 under existing levels of control, posed by widely disparate categories of
 environmental problem areas including accidental oil spills, active hazardous
 waste sites, and depletion of the stratospheric ozone layer.  Because  of
 inconsistencies in the scope and scale of each problem area, types of
 potential and actual ecological damage caused by each problem area, and levels
 of data availability for each problem area, the ERWG recognized the need for  a
 methodology that differed from a formal risk assessment procedure.
 Consequently, the ERWG used a semi-quantitative damage assessment procedure
 that relied in large part on the considered judgment of experts.

     The procedure followed by the ERWG and the expert panel involved five
 major steps.  First, the specific types of ecological stress agents associated
 with each environmental problem area were identified.  Second, a set of
 terrestrial and aquatic ecosystem categories was defined.   In the third step,
 the expert panel qualitatively evaluated the potential effects of each stress
 agent on the structure and function of each type of ecosystem, the
 reversibility of these impacts, and the time it would take  for the ecosystem
 to recover after the stress agent was removed, and characterized the
 geographic scale of these effects.  In the fourth step, papers were prepared
 for each problem area summarizing available information on  sources and
 emissions, exposure, potential impacts on ecosystems, level of control,  and
 quality of the available information.  Finally, using these papers, each
member of the ERWG subjectively prepared an aggregate ranking  of each problem
 area (low, medium, or high) based on a separate ranking of  effects  on each
 ecosystem.  The individual rankings were tabulated, and a final  ranking  was
determined by consensus.

 7.4.2  Description of Method

     Receptor Characterization

     The analysis focused on a generic set of  16  different  freshwater, marine,
estuarine, terrestrial, and wetland ecosystems.   Analysis of  hazard included
consideration of impacts on community structure  (e.g.,  alterations in trophic
structure or species diversity), community function (e.g.,  alterations  in
primary production or rates of nutrient cycling),  and particular species
 (e.g.,  endangered or economically important  species).   No specific temporal  ou

-------
Comparative Risk Project        EPA/OPPE  1987               Page C-90

niche characteristics were included routinely,  although  they may have been
considered in some assessments.

     Hazard Assessment

     Hazard assessment focused mainly on  a qualitative evaluation of the
potential impacts resulting from each stress  agent  (not  from problem areas
directly).   Stress agents included those  transported through the atmosphere
(e.g., gaseous phytotoxicants,  acid deposition),  those transported  through
surface water (e.g., pesticides,  toxic inorganics,  nutrients),  those applied
directly to terrestrial systems (e.g., pesticides,  solid matter), and others
(e.g., habitat alteration, ground-water contamination).   Potential  effects
were estimated first with respect to the  scale  at which  impacts would likely
occur (e.g.,  local, regional, global). Next,  the potential effects of  each
stress agent on each ecosystem were -evaluated with  respect to  their potential
intensity (high, medium, low, no effect), the nature of  the effect  (e.g.,
effects on ecosystem structure and function or  on endangered or economically
important species), the reversibility of  the impacts, and the  probable  time
scale for recovery following removal of the stress  agent (years, decades,
centuries,  indefinite).

     In most cases, the assessment was based on known effects  on  surrogate
individual/population receptors rather than on direct ecosystem dose-response
data.  For some problem areas with a small number of stress agents  (e.g.,  acid
deposition),  data on acute or chronic toxicity to individual  species  were used
to evaluate hazard.  However, most chemical stress  agents considered were
defined on the basis of chemical class (e.g., pesticides and herbicides,
nutrients,  toxic organics), so it is unclear whether toxicity was  assessed on
the basis of the most toxic constituent,  the least toxic constituent,  or some
average toxicity value.

     Certain modifying factors were considered for each stress agent.   Several
ecosystems (freshwater lakes, streams, and wetlands) were defined on the basis
of whether or not they were buffered.  Wetlands also were defined on the basis
of whether or not they were  isolated  from other flowing surface water.   Other
modifying factors considered in evaluating hazard included water hardness (for
inorganic chemicals) and bioaccumulation  (for organic chemicals).

     A qualitative assessment of the  uncertainty associated with each  stress
agent/ecosystem hazard assessment was  included.  Situations in which the data
and understanding were sufficient for  certain or probable  assessments  were
differentiated from those in which  the stress-response  relationship was poorly
understood or adverse responses occurred infrequently.  Qualitative
assessments of the quality of data  available also were  included in each
problem area summary paper.

     In the final ranking scheme, the greatest weight was placed on  the  scale
of impact of each problem area, followed by  the  reversibility of potential
effects.  However, no particular weighting criteria were  presented.   In
particular, it is unclear how  the aggregate  rankings of each  problem area were
determined from the separate rankings of effects on each ecosystem.

-------
 Comparative Risk Project        EPA/OPPE 1987               Page C-91

      Exposure  Assessment

      Exposure  assessment was presented only in each problem area summary paper
 (exposure  was  not considered in evaluating impacts of stress agents on
 ecosystems)  and  included geographical extent, intensity, and frequency.   All
 exposure pathways relevant  to a particular problem area were considered.
 Exposure data  consisted primarily of summary statistics on release quantities
 or  proportion  of a given ecosystem in which contaminant concentrations were in
 excess  of  applicable criteria.  No attempt was made to provide concentration
 estimation methods.  Data on toxicity modifying factors (e.g., water hardness,
 pH) were presented where available.  Qualitative estimates of uncertainty were
 included.

      Risk  Characterization

      The approach was highly qualitative and relied heavily on expert
 judgment.  Maximum emphasis  was placed on the integration of information on the
 hazards associated with multiple contaminants, multiple routes of exposure,
 and multiple stress agents  associated with a particular problem area.   Because
 it  is highly qualitative, this approach can be broadly applied to a wide range
 of environmental  problem areas.

     Treatment of uncertainty was also highly qualitative, reflecting
 uncertainty  in measurements as well as biotic and ecological  impacts.   No
 quantitative estimates (e.g., probability distributions, confidence intervals)
 were possible with 'this approach.

     The approach could be  validated internally by having a number of
 different  work groups evaluate each problem area and compare  their final
 relative rankings.  External validation, calibration, or sensitivity
 evaluation would  not be possible.

     The approach as documented cannot be verified, because several critical
 steps cannot be reconstructed.  Particularly absent are algorithms for
 aggregating component scores.

 7.4.3  Operational  Resource Requirements

     For most problem areas, a limited amount of data  (e.g.,  receptors,
 chemicals) are available.   The approach allows comparison of  problem  areas
with widely varied data bases.  The cost and level of effort  involved in using
 this approach are  low relative to those associated with a similar effort based
 on quantitative risk assessments.  However, proper use of this  method requires
 the highest level  of skill, experience, and ecological knowledge.

 7.4.4  Summary

     The Comparative Ecological Risk approach is not a  formal risk assessment
procedure  aimed at  quantifying ecological risks.  Instead,  it is a semi-
quantitative damage assessment method aimed at ranking  relative ecological
risks posed by major environmental problem areas.  Such a method is  probably
 the only practical  means for comparing the relative  risks associated  with

-------
Comparative Risk Project        EPA/OPPE 1987               Page C-92

widely disparate problem areas, particularly on a regional or national level.
Its strengths lie in its ability to provide a broad integration of data on
known exposures, potential hazards, and multiple pathways and stresses.  For
example, the problem areas receiving the highest risk ranking (stratospheric
ozone depletion, CC>2 and global warming) were not those for which data were
most available.  The main limitations of this approach are its high reliance
on qualitative judgments and the absence of repeatability due to a lack of
sufficient documentation for some of the critical steps.

-------