From: Shine, Brenda <Shine.Brenda@epa.gov> 

Sent: Thursday, April 17, 2014 4:55 PM 

To: Cortney Higgins 

Cc: Lassiter, Penny; Rimer, Kelly 

Subject: Petroleum Refinery RTR--- Interagency Comments under EO12866--- Supporting 

Information for Ecological Risk 

Cortney, 

Here are two documents related to the ecological risk assessment. 

They are: 

1)The environmental risk screen reference for Generic Ecological Risk Assessment Endpoints 

(GEAEs), and 

2) New Appendix 11 to the risk report that includes the ecological benchmarks 

<< GENERIC_ENDPOINTS_2003.pdf >> 

<< Appendix 11.pdf >> 
 EPA/630/P-02/004F 

October 2003 

Generic Ecological Assessment Endpoints (GEAEs) 

for Ecological Risk Assessment 

Risk Assessment Forum

U.S. Environmental Protection Agency

Washington, DC 20460
DISCLAIMER 

This document has been reviewed in accordance with U.S. Environmental Protection 

Agency policy. Mention of trade names or commercial products does not constitute 

endorsement or recommendation for use. 

ii 
CONTENTS

PREFACE ...................................................................v

AUTHORS, CONTRIBUTORS, AND REVIEWERS ................................ vi

1. INTRODUCTION: PURPOSE OF THIS DOCUMENT ............................1

1.1. Definitions of Assessment Endpoints .......................................1

1.2. Potential Uses for Generic Assessment Endpoints .............................3

1.3. Criteria for GEAEs .....................................................5

2. EPA’s INITIAL SET OF GEAEs ..............................................7

2.1. Definitions of the GEAEs Organisms ......................................13

2.2. Assessment Populations and Communities .................................16

3. HOW TO USE THE GEAEs .................................................19

3.1. Using GEAEs in Assessment Endpoint Selection ............................19

3.2. Making the Generic Endpoints Specific ....................................20

3.3. Other Ecological Assessment Endpoints ...................................21

3.4. Completing a List of Assessment Endpoints for a Specific Assessment ...........22

4. RECOMMENDATIONS FOR FURTHER PROGRESS ...........................23

4.1. Develop and Support a Continual, Open Process for Reviewing, Amending,

and Creating New GEAEs ..............................................23

4.2. Develop a Database to Document and Keep Track of New Rationales,

Precedents, and Assessment Endpoints ....................................24

4.3. Potential GEAEs for Future Consideration .................................25

5. CONCLUSION ...........................................................27

APPENDIX A. SUPPORTING INFORMATION ...................................28

APPENDIX B. TYPES OF VALUES ASSOCIATED WITH ASSESSMENT 

ENDPOINTS ..................................................52

REFERENCES ..............................................................54

iii 
LIST OF TABLES 

2-1. Generic ecological assessment endpoints .......................................8

2-2. Generic ecological assessment endpoints (GEAEs): summary of the policy support for 

their use and their practicality ................................................9

4-1. Potential GEAEs .........................................................24

LIST OF FIGURES 

1-1. Application of generic ecological assessment endpoints (GEAEs) in risk assessment ....2

iv 
PREFACE 

Ecological risk assessment is a process for evaluating the likelihood that adverse 

ecological effects may occur or are occurring as a result of exposure to one or more stressors. A 

critical early step in conducting an ecological risk assessment is deciding which aspects of the 

environment will be selected for evaluation. This step is often challenging because of the 

remarkable diversity of species, ecological communities, and ecological functions from which to 

choose and because of statutory ambiguity regarding what is to be protected. The purpose of this 

document is to build on existing EPA guidance and experience to assist those who are involved 

in ecological risk assessments in carrying out this step, which in the parlance of ecological risk 

assessment is termed “selecting assessment endpoints.” The document describes a set of 

endpoints, known as generic ecological assessment endpoints (GEAEs), that can be considered 

and adapted for specific ecological risk assessments. 

This document was prepared by a Technical Panel under the auspices of EPA’s Risk 

Assessment Forum. The Risk Assessment Forum was established to promote scientific 

consensus on risk assessment issues and to incorporate this consensus into appropriate risk 

assessment guidance. To accomplish this, the Forum assembles experts from throughout EPA in 

a formal process to study and report on these issues from an Agency-wide perspective. The 

document reflects the Forum’s long-standing commitment to advancing ecological risk 

assessment and is intended to supplement the use of the Forum’s Guidelines for Ecological Risk 

Assessment (U.S. EPA, 1998a). Following the publication of the guidelines, the Forum surveyed 

ecological risk assessors from across the Agency to prioritize and select risk assessment topics 

for further development. Additional guidance on assessment endpoints emerged as one of the 

highest-priority topics. A subsequent EPA colloquium sponsored by the Forum to consider high 

priorities from the survey identified a need for Agency-wide generic ecological assessment 

endpoints and directly led to the development of this document. 

The primary goal of this document is to enhance the application of ecological risk 

assessment at EPA, thereby improving the scientific basis for ecological risk management 

decisions. However, the document is not a regulation, nor is it intended to substitute for federal 

regulations. It describes general principles and is not prescriptive. Rather, it is intended to be a 

useful starting point that is flexible enough to be applied to many different types of ecological 

risk assessments. Risk assessors and risk managers at EPA are the primary audience; the 

document also may be useful to others outside the Agency. 

v 
AUTHORS, CONTRIBUTORS, AND REVIEWERS

This report was prepared by a Technical Panel of EPA scientists under the auspices of 

EPA’s Risk Assessment Forum. 

Technical Panel 

Glenn W. Suter II (Chair) 

National Center for Environmental 

Assessment 

Office of Research and Development 

U.S. EPA 

Cincinnati, OH 45268 

Thomas Gardner

Office of Science and Technology

Office of Water

U.S. EPA

Washington, DC 20460

Donald J. Rodier

Office of Pollution Prevention and Toxics

Office of Prevention, Pesticides, and

Toxic Substances 

U.S. EPA 

Washington, DC 20460 

Michael E. Troyer

National Center for Environmental

Assessment 

Office of Research and Development 

U.S. EPA 

Cincinnati, OH 45268 

Patti Lynne Tyler

Office of Technical and Management

Services 

Region 8 

U.S. EPA 

Denver, CO 80202 

Douglas J. Urban 

Office of Pesticide Programs

Office of Prevention, Pesticides, and

Toxic Substances 

U.S. EPA 

Washington, DC 20460 

Marjorie C. Wellman

Office of Science and Technology

Office of Water

U.S. EPA

Washington, DC 20460

Steven Wharton

Office of Partnerships and Regulatory

Assistance 

Region 8 

U.S. EPA 

Denver, CO 80202 

James White

Office of Air Quality Planning and

Standards 

Office of Air and Radiation 

U.S. EPA 

Research Triangle Park, NC 27711 

Risk Assessment Forum Staff 

Scott Schwenk

National Center for Environmental

Assessment 

Office of Research and Development 

U.S. EPA 

Washington, DC 20460 

vi 
AUTHORS, CONTRIBUTORS, AND REVIEWERS (continued) 

EPA REVIEWERS 

Jim Carleton

Office of Pesticide Programs

Office of Prevention, Pesticides, and

Toxic Substances 

U.S. EPA 

Washington, DC 20460 

Bruce Duncan

Office of Environmental Assessment

Region 10

U.S. EPA

Seattle, WA 98101

Anne Fairbrother

Western Ecology Division

National Health and Environmental

Effects Research Laboratory 

Office of Research and Development 

U.S. EPA 

Corvallis, OR 97333 

Gina Ferreira

Division of Environmental Planning and

Protection 

Region 2 

U.S. EPA 

New York, NY 10007-1866 

Laura Gabanski

Office of Wetlands, Oceans, and Watersheds

Office of Water

U.S. EPA

Washington, DC 20460

Jim Goodyear

Office of Pesticide Programs

Office of Prevention, Pesticides, and

Toxic Substances 

U.S. EPA 

Washington, DC 20460 

Amuel Kennedy

Office of Pollution Prevention and Toxics

Office of Prevention, Pesticides, and

Toxic Substances 

U.S. EPA 

Washington, DC 20460 

Wayne Munns

National Health and Environmental

Effects Research Laboratory 

Office of Research and Development 

U.S. EPA 

Narragansett, RI 02882 

Deirdre Murphy

Office of Air Quality Planning and

Standards 

Office of Air and Radiation 

U.S. EPA 

Research Triangle Park, NC 27711 

J. Vincent Nabholz

Office of Pollution Prevention and Toxics

Office of Prevention, Pesticides, and

Toxic Substances 

U.S. EPA 

Washington, DC 20460 

Vicki Sandiford

Office of Air Quality Planning and

Standards 

Office of Air and Radiation 

U.S. EPA 

Research Triangle Park, NC 27711 

Mike Slimak

National Center for Environmental

Assessment 

Office of Research and Development 

U.S. EPA 

Washington, DC 20460 

vii 
Barbara M. Smith

Policy and Management Division

Region 9

U.S. EPA

San Francisco, CA 94105

Sharon Thoms

Waste Management Division

Region 4

U.S. EPA

Atlanta, GA 30303-8960

Amy Vasu

Office of Air Quality Planning and

Standards 

Office of Air and Radiation 

U.S. EPA 

Research Triangle Park, NC 27711 

EXTERNAL PEER REVIEWERS 

William J. Adams

Rio Tinto HSE

Lawrence W. Barnthouse

LWB Environmental Services, Inc.

Peter M. Chapman

EVS Environment Consultants

Peter L. deFur

Center for Environmental Studies

Virginia Commonwealth University

John H. Gentile

Harwell Gentile & Associates, LC

Bruce K. Hope

Land Quality Division

Oregon Department of Environmental 

Quality

Randall S. Wentsel

Office of Science Policy

Office of Research and Development

U.S. EPA

Washington, DC 20460

Jordan M. West

National Center for Environmental

Assessment 

Office of Research and Development 

U.S. EPA 

Washington, DC 20460 

Molly R. Whitworth

Office of Science Policy

Office of Research and Development

U.S. EPA

Washington, DC 20460

Lawrence A. Kapustka

ecological planning and toxicology, inc.

Charles A. Menzie

Menzie-Cura & Associates, Inc.

Donald Norman

Norman Wildlife Consulting

James M. Polisini

Department of Toxic Substances Control

California EPA

Ralph G. Stahl, Jr.

DuPont Company

Kent. W. Thornton

FTN Associates, Ltd.

viii 
1. INTRODUCTION: PURPOSE OF THIS DOCUMENT 

In the practice of ecological risk 

assessment, assessment endpoints are the valued 

attributes of ecological entities upon which risk 

management actions are focused (U.S. EPA, 

1998a). Because not all organisms or ecosystem 

features can be studied, regulatory agencies and 

other risk managers must choose from among 

many candidate endpoints. A recommendation 

for improving ecological risk assessment and 

management within the U.S. Environmental 

Protection Agency (EPA, or the Agency) has 

been to develop a set of generic assessment 

endpoints that are based on environmental 

legislation and EPA’s policies and precedents and 

that cover EPA’s range of concerns for the 

protection of ecological entities and functions. 

In response to that recommendation, this 

document presents a set of generic ecological 

assessment endpoints (GEAEs) that provides 

examples of endpoints applicable to a wide 

variety of assessment scenarios. It also provides 

guidance for using these GEAEs to develop 

robust, assessment-specific endpoints. The role 

of assessment endpoints within the ecological 

risk assessment is shown in the text box. The 

application of GEAEs to the process of 

The role of assessment endpoints in 

EPA’s framework for ecological 

risk assessment 

Ecological risk assessments are 

preceded by a planning phase in which 

risk managers, risk assessors, and, as 

appropriate, interested parties define the 

management goals. The goals are broad 

statements of desired conditions such as 

“restore the wetlands” or “sustain the 

trout population.” 

The planning phase is followed by the 

problem formulation phase, in which the 

assessors define the assessment 

endpoints based on the management 

goals. The assessment endpoints are 

specific entities and their attributes that 

are at risk and that are expressions of a 

management goal. 

The analysis and risk characterization 

phases of the risk assessment are devoted 

to estimating the nature and likelihood of 

effects on those endpoints. 

Finally, risk communication involves 

conveying those results and associated 

uncertainties as well as explaining their 

implications. These processes are 

explained in Guidelines for Ecological 

Risk Assessment (U.S. EPA, 1998a). 

generating and using assessment endpoints in ecological risk assessments is illustrated in Figure 

1-1. 

1.1. Definitions of Assessment Endpoints 

An assessment endpoint is defined in Guidelines for Ecological Risk Assessment (U.S. 

EPA, 1998a) as “an explicit expression of the environmental value to be protected, operationally 

defined as an ecological entity and its attributes.” An ecological entity for example, might be an 

1
Planning 

Problem 

Formulation 

Analysis and Risk 

Characterization 

Management 

Goals 

Assessment 

Endpoints 

Risk Estimates for 

Each Endpoint 

GEAEs

Figure 1-1. Application of generic ecological assessment endpoints (GEAEs) 

in risk assessment. The process of generating and using ecological assessment 

endpoints and showing how GEAEs are used along with management goals in the 

selection of assessment endpoints during problem formulation. Rectangles 

represent assessment processes and hexagons represent the products of those 

processes. 

important fish species, such as coho salmon, with its attributes being fecundity and recruitment. 

Effects on assessment endpoints are estimated using measures of effects (see text box). The 

guidelines provide three selection criteria: ecological relevance, susceptibility (exposure plus 

sensitivity), and relevance to management goals. Selecting appropriate assessment endpoints is 

a critical step in ensuring that an assessment will be useful to risk managers in making informed 

2
and scientifically defensible environmental 

decisions. 

GEAEs are assessment endpoints that are 

applicable to a wide range of ecological risk 

assessments (ERAs) because they reflect the 

programmatic goals of the Agency, they are 

applicable to a wide array of environmental 

issues, and they may be estimated using existing 

assessment tools. GEAEs do not comprise a 

complete list of what is or, by exclusion, what is 

not protected by EPA. They are not specifically 

defined for every conceivable case, and some ad 

hoc elaboration by users is expected (Section 

3.3). Furthermore, they are not goals or 

objectives, but they should be related to goals or 

objectives when such are known. For example, a 

generic endpoint could be created for endangered 

species, but the specific species of concern 

would be defined during problem formulation, 

and attributes of the species could be selected to 

fulfill the goals of the Endangered Species Act, 

The relationship of measures of effects 

with assessment endpoints 

Measures of effects (also known as 

measurement endpoints) are the results of 

tests or observational studies that are used 

to estimate the effects on an assessment 

endpoint of exposure to a stressor. For 

example, a conventional measure of effect 

from an acute lethality test is the median 

lethal concentration (LC50), which might 

be used to estimate the risk of a fish kill 

(an assessment endpoint) from exposure 

to a spill of the tested chemical. 

Measures of effect and assessment 

endpoints may be expressed at the same 

level of organization (organism level in 

this case). However, the same measure of 

effect may be used, with considerably 

greater uncertainty, to estimate risks to a 

population-level assessment endpoint 

(abundance of a fish species) or a 

community-level endpoint (number of 

species). 

the recovery plan for the species, and the objectives of the particular assessment. 

Published generic endpoints are available for regional assessments (Suter, 1990), 

population assessments (Suter and Donker, 1993), assessments of hazardous waste combustors 

(U.S. EPA, 1999a), and assessments of contaminated sites in Alaska (Alaska Department of 

Environmental Conservation, 2000). In addition, examples of ecological assessment endpoints 

evaluated within certain EPA programs have been highlighted in prior EPA documents (U.S. 

EPA, 1994, 1997a, c, 1998a). These examples are presented, as appropriate, in Appendix A. 

1.2. Potential Uses for Generic Assessment Endpoints 

The set of generic assessment endpoints proposed in Section 2 of this document should 

be useful for risk assessors and managers involved in planning and performing ecological risk 

assessments within various EPA programs and offices. In particular, this document can be 

consulted during the problem formulation stage of ecological risk assessments to assist in 

developing assessment endpoints that are useful in EPA’s decision-making process, practical to 

measure, and well defined. In addition, the specific environmental laws, precedents, and other 

3
polices presented in Appendix A, which provide the supporting information for this initial set of 

generic endpoints of this document, should be equally useful in supporting assessment-specific 

endpoints. 

Individual programs may have specific uses for these generic endpoints beyond 

ecological risk assessments. For example, water quality management programs may want to 

consider using this information during the process of refining designated aquatic life uses in state 

and tribal water quality standards, when re-evaluating or developing guidance for consistent and 

environmentally relevant monitoring programs, and in interpreting and implementing narrative 

water quality standards. In particular, this set of generic endpoints may be useful within the 

context of a total maximum daily load for a water body that has been listed for nonsupport of 

aquatic life, but where there are no numeric biocriteria in the state’s water quality standards. 

This set of generic endpoints could be used to assist in the selection of appropriate ecological 

response variables or to judge the effectiveness of the pollutant reductions. 

Ultimately, generic assessment endpoints could have several other uses within the 

Agency, such as in 

• Giving risk managers a basis for action similar to commonly employed human health 

endpoints; 

• Providing a threshold for prevention of environmental degradation by ensuring that 

certain values are at least considered for assessment; 

• Complying with legal requirements; 

• Improving the consistency of ecological risk assessment and management; 

• Serving as models for site-, action-, or region-specific endpoints; 

• Performing screening ecological risk assessments where endpoints may need to be 

developed rapidly with little input from risk managers; 

• Providing clear direction for the development of methods and models; 

• Facilitating communication with stakeholders by creating a set of familiar and clear 

generic endpoints; and 

• Reducing the time and effort required to conduct assessments. 

These uses are described more fully in Suter (2000). 

It is important to emphasize that the generic assessment endpoints are not mandatory or 

applicable to all assessments. These particular generic endpoints should be used only when and 

4
where they are relevant. In many cases, it is likely that the endpoints derived from the generic 

assessment endpoints will be supplemented by other assessment endpoints that are relevant to 

the specific stressor or ecosystem. Over time, EPA anticipates that this initial set of generic 

ecological assessment endpoints will be periodically reviewed, modified, and supplemented as 

experience is gained in applying and interpreting them in a variety of natural conditions and 

regulatory contexts (see Section 4). 

1.3. Criteria for GEAEs 

Like assessment endpoints developed for specific risk assessments, the GEAEs presented 

in this report are intended to be useful in EPA decision making and to have a sound basis in 

ecological theory. The following criteria are used in this report for evaluating potential GEAEs; 

they are independent of specific assessment situations and in that way differ from the criteria that 

should be used in developing assessment-specific endpoints (see the text box in Chapter 3). 

1. Generally useful in EPA’s decision-making process. Usefulness may be indicated 

by the language found in statutes, treaties, and regulations that the Agency implements or with 

which it must comply. Judicial decisions also indicate how the values defined by statutes may 

be translated into generically useful endpoints. In addition, Agency guidance, guidelines, 

protocols, and official memoranda indicate potentially useful endpoints. Finally, various actions 

of the Agency that were based on ecological protection (i.e., Agency precedents) provide 

evidence of general utility for GEAEs. These various sources of environmental policy are 

summarized in U.S. EPA (1994, 1997a). Additional sources are referenced in Appendix A. 

Note that the reliance on available policy and precedent in this document should not suggest a 

similar restraint on risk assessors and managers in practice. EPA has a broad mandate to protect 

the environment that can support the use of novel endpoints in individual assessments (see 

Sections 3 and 4). 

2. Practical. Methods used to estimate risks to the endpoint entity and attribute should 

be available and reasonably practicable in various assessment contexts. This requires methods 

that directly measure or observe the endpoint’s attributes or that estimate them using a 

combination of measurements and models. However, this does not require that a GEAE be 

useful for all situations. Some GEAEs will not be implementable for some taxa or ecosystems, 

but they should be practical in many situations. 

3. Well defined. At a minimum, a GEAE must include an entity and an attribute of that 

entity (U.S. EPA, 1998a). The entity and attribute should be clearly explained, so that they are 

5
understandable by the public and decisionmakers without appearing ambiguous to environmental 

scientists. A definition should be supported by a clear explanation of the endpoint’s relationship 

with the Agency’s management goals and programmatic applications. 

Support for the first two criteria (usefulness and practicality) is presented in Appendix A 

and summarized in Table 2-2. The third criterion (that GEAEs be well defined) is supported by 

the definitions in Section 2.1 and supplemented by the background in Appendix A. 

6
2. EPA’s INITIAL SET OF GEAEs 

This chapter presents EPA’s initial set of GEAEs to be considered for the uses described 

in Section 1.2. As stated, these GEAEs are not exhaustive or mandatory but rather are provided 

to assist EPA programs and researchers and decisionmakers who are involved in protecting the 

nation’s ecological resources, as described in Section 3. The entities and properties in the initial 

set of GEAEs are presented in Table 2-1. The specific taxa, communities, or ecosystems for 

which policy or precedents were identified are listed in the last column of the table. The GEAEs 

are defined in Section 2.1, and the basis for the terms “assessment community” and “assessment 

population,” which are used in the definitions, is 

explained in Section 2.2. Information concerning 

laws, regulations, and precedents that support the 

selection and use of these GEAEs is presented in 

Appendix A and summarized in Table 2-2. A 

general discussion of the values related to these 

GEAEs is presented in Appendix B. Other 

potential GEAEs that were promising but did not 

fully meet the criteria in Section 1.3 are 

discussed in Section 4. 

These GEAEs are not always biologically 

distinct, but the apparent overlaps are justified in 

pragmatic terms. For example, the generic 

endpoint “population extirpation” is an extreme 

case of the generic endpoint “population 

abundance.” However, the extirpation of a 

population is qualitatively different from a 

simple percentage loss of abundance. The 

implications of reductions in fish abundance 

include a loss of fishing income, but extirpation 

Overlap of GEAEs 

GEAEs are not necessarily discrete 

or mutually exclusive; therefore, there 

may be some redundancy in a set of 

GEAEs. For example, the condition of 

an ecological entity at one level of 

biological organization (e.g., organism) 

may influence the condition of other 

entities at that level and interdependent 

entities at higher levels of organization 

(e.g., population or community). 

Also, a large change in one attribute 

may overlap with another attribute, as in 

the case of abundance and extirpation. 

Furthermore, GEAEs may relate to more 

than one environmental value (see 

Appendix B), which may be reflected in 

multiple statutes, regulations, public 

policies, or public perceptions (see 

Appendix A). 

means an end to the fishery. In addition, it is typically much easier to establish that extirpation 

has occurred (e.g., the fish are no longer caught) or will occur (e.g., the trout stream will be 

inundated by a reservoir, or the pH will be far beyond the lethal level) than to establish that some 

percentage reduction in abundance has occurred or will occur. This difference in implications 

for the assessment and decision-making processes justify treating extirpation and abundance as 

different endpoints. 

7
Similarly, kills of organisms have short-term effects on population abundance but do not 

necessarily have a significant or long-term effect on abundance. The methods for determining 

Table 2-1. Generic ecological assessment endpointsa 

Entity Attribute Identified EPA precedents 

Organism-level endpoints 

Organisms (in an assessment 

population or community) 

Kills (mass mortality, conspicuous 

mortality) 

Vertebrates 

Gross anomalies Vertebrates 

Shellfish 

Plants 

Survival, fecundity, growth Endangered species 

Migratory birds 

Marine mammals 

Bald and golden eagles 

Vertebrates 

Invertebrates 

Plants 

Population-level endpoints 

Assessment population Extirpation Vertebrates 

Abundance Vertebrates 

Shellfish 

Production Vertebrates (game/resource species) 

Plants (harvested species) 

Aquatic communities 

Coral reefs 

Aquatic communities 

Plant assemblages 

Wetlands 

Coral reefs 

Endangered/rare ecosystems 

Community and ecosystem-level endpoints 

Assessment communities, 

assemblages, and ecosystems 

Taxa richness 

Abundance 

Production 

Area 

Function Wetlands 

Physical structure Aquatic ecosystems 

Officially designated endpoints 

Critical habitat for threatened or 

endangered species 

Area 

Quality 

Special places Ecological properties that relate to 

the special or legally protected 

status 

e.g., National parks, national 

wildlife refuges, Great Lakes 

a

Generic ecological assessment endpoints for which EPA has identified existing policies and precedents, in 

particular the specific entities listed in the third column. Bold indicates protection by federal statute. See Table 4-1 

for additional endpoints that could be considered by EPA in the future. 

8
Table 2-2. Generic ecological assessment endpoints (GEAEs): summary of the policy support for their 

use and their practicalitya 

GEAE # Entity: Policy support Practicality 

Organism-level endpoints 

1 Organisms: 

(mass mortality, 

conspicuous 

mortality) 

Supported by many EPA programs; 

e.g., EPA has restricted the use of 

pesticides (e.g., diazinon and 

carbofuran) due to incidents of bird 

mortality. 

Likelihood of kills from chemical 

pollutants can be estimated from 

toxicity testing. ay be 

easy or difficult to observe, but when 

seen, they suggest a common 

mechanism or stressor exerting a 

strong effect. 

2 Organisms: 

anomalies 

Gross anomalies in birds, fish, 

shellfish, and other organisms are a 

cause for public concern and have 

been the basis for EPA regulatory 

action and guidance (e.g., assessed 

at Superfund sites, incorporated into 

biocriteria for water programs). 

External gross anomalies are readily 

observed and are commonly included 

in survey protocols for fish and 

forests. 

toxicity tests of fish, birds, mammals, 

and plants. 

3 Organisms: 

fecundity, growth 

Many EPA programs rely on 

organism-level attributes of 

survival, fecundity, and growth in 

assessing ecological risks (e.g., 

water quality criteria, pesticide and 

toxic chemical reviews, Superfund 

sites). -level species 

protection is mandated by the 

Endangered Species Act, Marine 

Mammal Protection Act, Bald Eagle 

Protection Act, and Migratory Bird 

Treaty Act. 

Results of toxicity tests of the 

survival, fecundity, and growth of 

organisms are abundant and often 

can be extrapolated to endangered 

species and other species of concern. 

Information on the ranges of listed 

endangered species is available 

through state and federal 

governments. 

Population-level endpoints 

attribute(s) 

kills 

Incidents m

gross 

They are also reported in 

survival, 

Organism

4 Assessment 

population: 

extirpation 

EPA has taken action or provided 

guidance to prevent extirpation of 

local populations (e.g., assessment 

of likelihood of extirpation of fish 

populations due to acid rain). 

also the description for Assessment 

population: 

Extirpation can be predicted using 

population viability analysis. 

Demonstrating extirpation may be 

easy or difficult, depending on the 

conspicuousness of a species. 

also the description for Assessment 

population: abundance. 

See 

abundance. 

See 

9
Table 2-2. Generic ecological assessment endpoints (GEAEs): summary of 

the policy support for their use and their practicalitya (continued) 

GEAE # Entity: Policy support Practicality 

5 Assessment 

population: 

abundance 

Major environmental statutes 

mandate protection of animals, 

plants, aquatic life, and living things 

generally, which can be inferred to 

entail protection of populations. 

EPA policies for pesticides, toxic 

chemicals, hazardous wastes, and 

air and water pollutants are intended 

to protect assessment populations of 

organisms. mals, birds, fish, 

aquatic invertebrates, and plants are 

typically assessed. 

Changes in abundance may be 

predicted using conventional toxicity 

data with statistical extrapolation 

models and population models. 

OPPT evaluated a population model 

to explore effects of chloroparaffins 

on fish populations. ent of 

abundance in the field may be easy 

or difficult, depending on the 

species. 

6 Assessment 

population: 

production 

See description for Assessment 

population: 

Additionally, a number of laws are 

intended to maintain production of 

various economically valuable 

species. s (e.g., 

National Estuary Program) and air 

programs (e.g., criteria pollutant 

standards) have involved protecting 

production of resource species 

populations. 

Changes in production may be 

predicted using conventional toxicity 

data as well as population-based 

approaches. 

such as tree or fish species, 

production changes may be 

measurable in the field but may 

require long periods of observation. 

Community and ecosystem-level endpoints 

7 Assessment 

communities, 

assemblages, and 

ecosystems: 

richness 

EPA water quality biocriteria 

frequently incorporate measures of 

community taxa richness. 

Additionally, EPA testing for 

pesticides, toxic chemicals, and 

water pollutants is intended to 

assess impacts to communities as 

well as populations and organisms. 

Fish, aquatic invertebrates, and 

aquatic plant assemblages are often 

assessed. 

Changes in communities can be 

inferred or modeled from 

conventional toxicity data. 

Measuring taxa richness and 

abundance of aquatic communities, 

at least for fish and 

macroinvertebrate communities, is 

practical and well established. 

Ecosystem models that assess effects 

of toxicants on community properties 

are available and can use data 

acquired from organism-level 

laboratory testing, but they have not 

been routinely applied to date. 

8 Assessment 

communities, 

assemblages, and 

ecosystems: 

abundance 

As in the case of taxa richness, 

water quality biocriteria incorporate 

measures of community abundance, 

and EPA testing protocols are 

intended to assess impacts to 

communities. 

See description above for taxa 

richness within assessment 

communities. 

attribute(s) 

Mam

Measurem

abundance. 

EPA water program

For resource species 

taxa 

10
Table 2-2. Generic ecological assessment endpoints (GEAEs): summary of 

the policy support for their use and their practicalitya (continued) 

GEAE # Entity: Policy support Practicality 

9 Assessment 

communities, 

assemblages, and 

ecosystems: 

production 

EPA water quality policies address 

overproduction of aquatic plants 

(and concomitant eutrophication) 

due to excess input of nutrients. 

EPA policies for pesticides, toxic 

chemicals, water pollutants, and air 

pollutants (as in the case of ozone 

and acid rain) also target decreases 

in production of forests or other 

plant communities. 

Methods for measuring plant 

production are well developed for 

both terrestrial and aquatic 

communities. 

predicting effects of nutrient addition 

are relatively well developed. 

Protocols for testing plant toxicity 

are available and include production 

metrics. 

10 Assessment 

communities, 

assemblages, and 

ecosystems: 

Policy support exists for 

considering the area of wetlands, 

coral reefs, and endangered/rare 

ecosystems. ong the supports 

for wetlands protection are the 

Clean Water Act, the National 

Environmental Policy Act (NEPA), 

the Coastal Zone Management Act, 

Executive Order 11990, and the 

federal wetlands delineation 

manual.b

 Policies for protection of 

coral reefs are established by 

Executive Order 13089; additional 

support may be found in the Coastal 

Zone Management Act and the 

Marine Protection, Research, and 

Sanctuaries Act. 

reefs are protected by state or 

federal government. 

precedents exist for endangered/ 

rare ecosystems, but a variety of 

EPA programs have considered 

them, e.g., Superfund and NEPA. 

Assessing the area of communities is 

generally straightforward, although 

when clear boundaries between 

communities are absent, defining 

areas may be somewhat difficult. 

Methods for delineating wetlands are 

well established, and changes in 

wetland area are therefore relatively 

easy to measure and monitor over 

time. 

relatively easy to determine. 

case of endangered and rare 

ecosystem types, a ready data source 

is NatureServec

, which maintains 

data on all known U.S. ecological 

communities, ranked from critically 

imperiled to secure. Prediction of 

change from one community or 

ecosystem type to another may be 

difficult. 

attribute(s) 

plant Methods for 

area Am

Many U.S. coral 

Fewer EPA 

The area of coral reefs is also 

In the 

11 Assessment 

communities, 

assemblages, and 

ecosystems: 

Policy support for ecosystem 

function is primarily limited to 

wetlands. 

protection cited above for 

community/ecosystem area 

generally applies to wetland 

function as well. 

Loss of wetland function can be 

inferred from loss of wetland area. 

However, losses of function 

independent of area loss generally 

are not readily observable or 

predictable. 

function 

The support for wetland 

11
Table 2-2. Generic ecological assessment endpoints (GEAEs): summary of 

the policy support for their use and their practicalitya (continued) 

GEAE # Entity: Policy support Practicality 

12 Assessment 

communities, 

assemblages, and 

ecosystems: 

structure 

The primary policy support for this 

endpoint derives from the Clean 

Water Act, which applies to aquatic 

ecosystems. 

maintaining the physical integrity 

(along with the chemical and 

biological integrity) of the nation's 

waters is the primary goal of the 

Clean Water Act. 

monitoring guidance under the Act 

include measures of physical 

structure. 

Protocols exist for measuring many 

of the physical characteristics of 

aquatic ecosystems. pacts of 

many actions (e.g., channelization, 

dam construction) on the physical 

structure of water bodies can be 

readily predicted. 

(such as hydrology changes due to 

land use changes) are more difficult, 

but still possible, to model. 

Officially designated endpoints 

13 Critical habitat for 

threatened and 

endangered species: 

area 

The Endangered Species Act 

specifically mandates the protection 

of critical habitat for endangered 

species in addition to the species 

themselves. 

available habitat is commonly used 

in assessing risks to these species. 

Information on habitat used by listed 

species is available from state and 

federal agencies, although critical 

habitat has not been officially 

designated for most listed species. 

Generally it is practical to determine 

effects on habitat area. 

14 Critical habitat for 

threatened and 

endangered species: 

quality 

Legal protection of critical habitat 

extends to the quality (suitability) of 

the habitat to endangered species, in 

addition to its extent. 

Assuming that critical habitat can be 

identified (even if not officially 

designated), it 

practical to determine whether it has 

been or will be adversely modified. 

15 Special places: 

ecological properties 

that make them 

special or legally 

protected 

The Clean Air Act, NEPA, and 

other statutes require protection of 

special places such as national 

parks, wilderness areas, and wildlife 

refuges, and this is reflected in EPA 

policies. ater Act 

gives EPA a role in designating 

national estuaries and outstanding 

national resource waters, which 

receive additional protection. 

Special places and their important 

ecological properties usually can be 

defined readily. The ability to predict 

or detect impacts to these properties 

will depend on the nature of the 

properties and whether impacts are 

direct or indirect. 

attribute(s) 

physical Restoring and 

EPA policies and 

The im

Other effects 

The area (quantity) of 

generally should be 

The Clean W

a

See Appendix A for details and references. 

b

Environmental Laboratory (1987) c

NatureServe’s web address is <http://www.natureserve.org>.

12
that a kill has occurred are much simpler than the methods for determining that the abundance of 

a population has changed. In addition, the effects on the public of a kill (such as concerns over 

odor and disease) are not necessarily related to effects on the populations involved. For 

example, public response to a fish kill may not be related to the ability of the fish populations 

involved to recover rapidly. Therefore, kills are distinct from both population abundance and 

extirpation in terms of assessment approaches and management implications. 

2.1. Definitions of the GEAEs Organisms 

Organisms are the most distinct units of ecology, and attributes of organisms have been 

the focus of EPA’s efforts to protect the environment. However, the use of organisms as 

endpoints does not necessarily imply that each individual is protected. Rather, “organisms” is a 

level of biological organization with certain attributes that may be the basis of management 

decisions. Although organisms of any species may be chosen as assessment endpoint entities, 

some species are protected at the organism level by statute, including (a) endangered and 

threatened species (those listed by the U.S. Fish and Wildlife Service or the National Marine 

Fisheries Service as in danger of extinction under the Endangered Species Act), (b) marine 

mammals that are protected by the Marine Mammal Protection Act (whales and porpoises, seals, 

sea lions, and walruses, polar bears, sea otters, and manatees), (c) bald eagles and golden eagles, 

which are protected by the Bald Eagle Protection Act, and (d) nearly all birds in the U.S., 

including their eggs and nests, which are protected by the Migratory Bird Treaty Act. 

1. Kills: an event or multiple events involving numerous mortalities of organisms 

within an assessment population or community. Kills may also be referred to as mass 

mortality or conspicuous mortality. These events may be repeated and wide-spread, as in 

bird kills due to pesticide applications; repeated at a location, as in fish kills due to 

repeated treatment failures; or a single event, as in a seabird kill due to an oil spill. They 

may involve one or more species. Precedents for this GEAE have involved vertebrates. 

2. Gross anomalies: deformities, lesions, or tumors in animals; death or necrosis of 

plant leaves; or other overt physical injuries of organisms within an assessment 

population or community. The occurrence of these injuries may involve one or more 

species. Precedents for this GEAE have involved vertebrates, shellfish, and terrestrial 

plants. 

3. Survival, fecundity, or growth: survival (which may be reduced by direct lethality 

or by sublethal effects that diminish survival probabilities), fecundity (the production of 

viable young), and growth (increased mass or length) of some proportion of the animals 

or plants in an assessment population or community are the basic attributes of concern for 

nonhuman organisms. In addition to the specific legal protections at the organism level 

13
for the groups discussed above, there are precedents for using these attributes for 

vertebrates, invertebrates and plants. 

Assessment population. An assessment population is a group of conspecific organisms 

occupying an area that has been defined as relevant to an ecological risk assessment. 

4. Extirpation: depletion of an assessment population to the point that it is no longer a 

viable resource or is unlikely to fulfill its function in the ecosystem. Precedents for this 

GEAE have involved vertebrates. 

5. Abundance: numbers or density of individuals in an assessment population. Total 

abundance or abundances by age or size classes may be used. Precedents have involved 

vertebrates and shellfish. 

6. Production: the generation of biomass or individuals in an assessment population 

due to survival, fecundity, or growth. Precedents have involved vertebrates (primarily 

game and resource species) and plants (primarily harvested species). 

Assessment community, assemblage, or ecosystem. A community is a multispecies 

group of organisms occupying an area that has been defined as relevant to an ecological risk 

assessment. Groups that are limited to organisms in a taxon (a plant community or bird 

community) or that are in certain size classes within a taxon (macroinvertebrates or zooplankton) 

are termed assemblages. Ecosystems are equivalent to communities but include the physical and 

chemical features of the environment. 

7. Taxa Richness: the number of native species or other taxa in an assessment 

community or assemblage. Precedents have involved aquatic communities and policies 

protecting coral reefs. 

8. Abundance: the number of individuals in an assessment community or assemblage. 

Total abundance or relative abundances of individual species, other taxa, trophic groups, 

or other ecologically defined groups may be used. Precedents have involved aquatic 

communities. 

9. Production: the generation of biomass or individuals in an assessment community or 

assemblage. Precedents for this GEAE have involved plant assemblages. The 

assemblage may include all plants in an area or water body, in a taxon (e.g., flowering 

plants), or in another definition (e.g., phytoplankton or above-ground herbs). 

10. Area: the area of an ecosystem may be defined as extent of a particular type (e.g., 

Atlantic white cedar bog) or a particular category (e.g., palustrine wetlands). Area is a 

protected attribute of wetlands and coral reefs. There are precedents for protecting the 

14
areal extent of endangered or rare ecosystem types, which are ecosystems that are at high 

risk of extinction because they are rare or significantly declining due to destruction or 

transformation to another type. The ecosystem may be generic (e.g., old growth or 

virgin forests in the conterminous U.S.) or geographically specific (e.g., Hempstead 

Plains grasslands on Long Island, NY). The National Biological Survey (Noss et al., 

1995) and the Association for Biodiversity Information, among others, have compiled 

information on rare and endangered ecosystem types. 

11. Function: processes performed by ecosystems that are services to humans or other 

ecological entities. Function is a protected attribute of wetlands. Functional attributes of 

wetlands may include water storage, maintenance of high water tables, nutrient retention 

and cycling, sediment retention, accumulation of organic matter, and maintenance of 

habitats for wetland-dependent plants and animals. 

12. Physical structure: precedents are limited to aquatic ecosystems. Physical 

structure encompasses the physical attributes or characteristics of water bodies, including 

hydrological characteristics, bathymetry, bank form, sinuosity, pool and riffle structure, 

bank and channel vegetation, and substrate type and composition. This endpoint includes 

the aesthetic and other values of aquatic ecosystem structure, not simply habitat quality 

for aquatic organisms. 

Critical habitat for threatened and endangered species. Critical habitat is the specific 

area within the geographical area occupied by an endangered or threatened species on which are 

found physical or biological features essential to the conservation of the species and that may 

require special management considerations and protections (16 U.S.C. 1532(5)). Critical 

habitats, legally defined and specified by the U.S. Secretary of Interior, are listed in 50 CFR, Ch. 

1, Sections 17.94–76. However, habitats that are critical to a threatened or endangered species 

should be protected when identified even if they are not listed. 

13. Area of critical habitat for threatened and endangered species: the land 

coverage or equivalent aquatic extent (e.g., stream kilometers) that potentially supports 

the endangered or threatened species. 

14. Quality of critical habitat for threatened and endangered species: the suitability 

of the habitat to support the endangered or threatened species. 

15. Properties of Special Places. Special places are public and private areas of 

ecological or cultural significance that are not necessarily endangered or threatened but whose 

unique character or natural heritage is important—as revealed by laws or other actions that set 

them aside. Examples include World Heritage sites, national parks and natural landmarks, 

wilderness areas, national wildlife refuges, national conservation areas, wild and scenic rivers, 

estuarine and marine sanctuaries, private nature preserves (e.g., Nature Conservancy preserves 

15
and National Audubon Society sanctuaries), and state and local parks. For a more 

comprehensive list, see U.S. EPA (1991a). The ecological properties to be protected are those 

that make the place special, including those that are an important part of the historical or cultural 

heritage of a place (e.g., shortgrass prairie at Little Bighorn National Monument). Hence, this 

GEAE is relevant only to special places with ecological properties that are important to their 

designation. We would not, for example, apply this GEAE to a renovation of Grant’s Tomb. 

2.2. Assessment Populations and Communities 

Because the conventional ecological meaning of “populations” and “communities” 

presents problems in practice, this document introduces the terms “assessment population” and 

“assessment community” (defined above). Although ecological assessment endpoints inevitably 

include population properties, such as abundance and production, and community properties, 

such as species richness, it is difficult to delineate populations and communities in the field. 

Classically defined populations are discrete and interbreeding. Classically defined communities 

are discrete and their constituent species are relatively consistent and interact in predictable 

ways. Although these classical definitions have been important to the development of genetics, 

evolution, and ecology (e.g., Hardy-Weinberg equilibrium and the competitive exclusion 

principle), they have always had manifest limitations in practice. 

More recently, ecology has become more focused on temporal dynamics, spatial patterns 

and processes, and stochasticity that belie the notion of static, independent populations. One 

example of this is metapopulation analysis, which reveals that population dynamics are 

significantly determined by exchange of individuals among habitat patches or differential 

movement across a landscape that continuously varies in suitability (Hanski, 1999). 

Communities are subject to the same dynamics. For example, the species diversity of Pacific 

coral reefs is apparently determined by the availability of recruits from other reefs within 600 km 

(Bellwood and Hughes, 2001). If the composition of coral reefs, which would appear to be 

classic discrete communities, is in fact determined by regional dynamics, there is little chance of 

delimiting discrete communities in general. 

Populations may be readily delimited if they are physically isolated within a broader 

species range (e.g., a sunfish population in a farm pond) or if the species consists of only one 

spatially discrete population (e.g., the endangered Florida panther, whose current range is 

restricted almost exclusively to southwest Florida). Otherwise, population boundaries are 

difficult to define because they are typically structured on multiple scales. Genetic analyses, 

which are needed to define discontinuities in interbreeding frequencies and thus to delimit 

populations, are not a practical option for most ecological risk assessments. 

16
The practical problems are even greater for communities. Although the members of a 

population consist of a single species, it is not always clear whether a particular group of 

organisms constitutes an instance of a particular community type. This is because the species 

composition of communities varies over space and time. 

To protect properties such as population production or community species richness, it is 

necessary to develop a pragmatic solution to these problems. An example of such a solution is 

the approach taken by the Nature Conservancy and NatureServe (formerly the Association for 

Biodiversity Information) to inventory and map biodiversity (Stein et al., 2000). Because it is 

not feasible to define discrete populations or communities, these organizations inventory and 

map occurrences of conservation elements, which may be defined at various scales, depending 

on the elements and circumstances. For example, a plant community occurrence may be “a stand 

or patch, or a cluster of stands or patches.” However, an occurrence of a bird species would be 

defined quite differently. 

We propose a similar approach for GEAEs. For individual assessments, the population 

or community entities to be protected must be defined during the problem formulation stage of 

risk assessment. These assessment populations and assessment communities should be defined 

in a way that is biologically reasonable, supportive of the decision, and pragmatic with respect to 

policy and legal considerations. For example, it would not be reasonable to define the belted 

kingfishers in a 20 m steam reach as an assessment population if that reach cannot fully support 

one belted kingfisher pair. On the other hand, even though the kingfisher’s range is effectively 

continuous, it would not be reasonable to define the entire species as the assessment population, 

given that it ranges across nearly all of North America. Rather, it may be reasonable to define 

the kingfishers on a watershed or a lake as an assessment population. 

Assessment populations may be defined by nonbiological considerations as well. For 

example, for Superfund ecological risk assessments on the U.S. Department of Energy’s Oak 

Ridge Reservation, populations of large terrestrial vertebrates were delimited by the borders of 

the reservation (Suter et al., 1994). This definition was reasonable not only because the 

Superfund site was defined as the entire reservation, but also because the reservation was large 

enough to sustain viable populations of deer, wild turkey, and bobcat, among others. Although 

the reservation is more forested than are the surrounding agricultural and residential lands, its 

borders are not impenetrable and are not ecologically distinct at all points. However, the 

pragmatic definition proved useful and acceptable to the parties. For similarly practical reasons, 

one might define an assessment community of benthic invertebrates in the first fully mixed reach 

of a stream receiving an effluent. 

The selection of a scale to define an assessment population or community involves a 

tradeoff. If the area is large relative to the extent of the stressor, the effects of that stressor will 

17
be diluted. However, if the area is small, the assessment population or community may be 

significantly affected but may seem too insignificant to prompt stakeholder concern or action by 

the decisionmaker. Hence, appropriate spatial scales should be determined during the problem 

formulation stage for individual risk assessments, taking into consideration both the ecological 

and policy aspects of the problem; it must not be manipulated during the analysis to achieve a 

desired result. 

18
3. HOW TO USE THE GEAEs 

In a risk assessment for a specific site, 

effluent, stressor, or action, it will be necessary to 

determine whether any of the GEAEs are 

applicable to the assessment and sufficient for the 

case, and if so, how they can be made specific to 

the case. These activities are performed as part of 

the problem formulation phase of risk assessment 

(U.S. EPA, 1998a). 

3.1. Using GEAEs in Assessment Endpoint 

Selection 

The set of GEAEs is intended to be 

helpful for identifying and specifically defining 

assessment endpoints for particular assessments. 

During problem formulation, risk assessors, 

scientists, risk managers, and any stakeholders 

identify endpoints that are relevant to the 

assessment, that are of sufficient importance to 

potentially influence the decision, and that reflect 

any goals that may have been set prior to the 

problem formulation (U.S. EPA, 1998a). The 

assessment-specific criteria for selecting 

assessment endpoints from the guidelines for 

ERA are used in that process (see text box). 

The process of developing assessment 

Criteria for selection of 

assessment endpoints 

EPA has provided criteria for 

developing assessment-specific 

assessment endpoints: ecological 

relevance, susceptibility, and relevance 

to management goals (U.S. EPA, 1998a, 

Section 3.3.2). 

Ecological relevance pertains to the 

role of the endpoint entity in the 

ecosystem and therefore depends on the 

ecological context. 

Susceptibility pertains to the 

sensitivity of the endpoint to the stressor 

relative to its potential exposure and 

therefore depends on the identity of the 

stressor and the mode of exposure. 

Relevance to management goals 

pertains to the goals set by the risk 

manager and therefore depends on the 

societal, legal, and regulatory context of 

the risk management decision as well as 

the preferences of the individual risk 

manager and stakeholders. 

These situation-specific criteria 

should be applied whenever GEAEs are 

converted to assessment endpoints in 

individual assessments. 

endpoints for an ecological risk assessment may be thought of as bringing together five types of 

information and answering questions related to each, as shown below. Together, the questions 

address the criteria for ecological assessment endpoints. The GEAEs constitute one type of 

information that answers one question. In addition, the table of GEAEs can be consulted while 

answering the other questions as a means of ensuring that commonly considered types of entities 

and attributes are considered. 

1. Stressor characteristics. What is susceptible to the stressor? For well-understood 

stressors, this question is straightforward. Benthic invertebrates are susceptible to 

19
dredging, birds are susceptible to granular pesticides, wetlands are susceptible to filling, 

and so on. 

2. Ecosystem and receptor characteristics. What is present and ecologically relevant? 

For site-specific assessments, this is the species, communities, or ecosystems at the site. 

For other assessments, the scenario should define the types of species communities and 

ecosystems that are likely to be exposed. For example, an assessment of a new pesticide 

for corn would consider the species likely to be found in or adjacent to corn fields in the 

midwestern U.S. In the absence of specific information about the particular importance 

of an entity, those that are present may be assumed to be ecologically relevant. 

3. Management goals. What is relevant to the management goals? Statements of 

management goals should suggest the changes in attributes of ecological entities that 

would preclude achieving the goal. 

4. Input by interested parties. What is of concern? If interested parties are consulted or 

make their preferences known, their concerns about particular ecological effects should 

be considered. Although societal values at a national scale are reflected in the GEAEs, 

values that are specific to a locale or resource are expressed by interested parties. 

5. GEAEs and new policies or precedents. What is supported by policy or precedent? 

The GEAEs defined in this report provide a set of entities and attributes that meet this 

criterion, which is an expression of national goals and values at the time of publication. 

The answers to each of these questions would be a list of potential assessment-specific 

endpoints. None of the questions imply absolute requirements. For example, susceptibility to a 

novel stressor may be unknown, and the concerns of interested parties are often unknown and 

often do not include important potential endpoints. 

No particular procedure is prescribed for this process of answering the questions or for 

using the GEAE set. If consistency with policy and precedent is particularly important, one 

might go through the GEAE set and ask the other four questions with respect to each generic 

endpoint. Alternatively, the questions might each be answered and the lists then integrated. In 

that case, the endpoints for a specific assessment may simply be those that are represented on 

most of the lists. 

3.2. Making the Generic Endpoints Specific 

To convert a GEAE into an assessment endpoint for a specific assessment, it is necessary 

to define the specific entity and attribute and the spatial and temporal context of the entity. This 

specificity is needed to make the endpoint relevant to the assessment and to determine which 

measurements and models are needed to estimate it. 

20
Consider the first GEAE, kills of organisms, as an example. The generic entity is 

organisms. For a specific assessment endpoint, we must specify whether the endpoint entity 

corresponds to members of a specific taxon such as fish or birds, an assemblage such as 

macroinvertebrates, or a specific species such as sea otters. The generic attribute is kills, which 

should be defined more specifically and in terms that are appropriate to the assessment. For 

example, the definition of a kill would differ for a well-monitored experimental use of a 

pesticide versus public reports of mortalities, for oil spills versus lawn treatments, and for 

modeling studies versus observational studies. Possible definitions could include the number of 

organisms that must die during an episode for it to be considered a kill, the proportion of 

organisms visiting a site that would be expected to die, or the frequency of public reports of dead 

organisms associated with the stressor. Finally, the spatial and temporal contexts should be 

defined. For an effluent, the contexts may be the downstream reach within which mixing occurs 

and the period of a permit. For a pesticide, they may be the region within which the pesticide is 

used on a particular crop and the number of applications per year over the period of use. For an 

oil spill, they may refer to the area encompassed by the plume and the time until the plume is 

dispersed or degraded to the point that it no longer oils marine birds or mammals. Hence, an 

assessment endpoint derived from this GEAE might be episodic mortality of at least 10 fish of 

any species occurring in the 1 km reach downstream of the effluent release point. 

The answers to the first four questions in Section 3.1 provide the basis for specific 

endpoint definitions; that is, they determine which specific organisms, populations, or 

ecosystems are susceptible and potentially exposed and which are of concern, the spatial and 

temporal scales that are relevant to management goals, and other relevant considerations. 

More than one assessment endpoint may be derived from a GEAE for a particular 

assessment. For example, the GEAE population abundance may be used to generate assessment 

endpoints for each of several populations of concern, and the change in abundance and spatial 

context may be different for each. On the other hand, a site-specific concern may relate to more 

than one GEAE. In the example of the wetland discussed in the previous chapter, the sitespecific problem formulation must determine whether the management concern and the evidence 

of wetland susceptibility are related to the area of the wetland, a functional attribute of the 

wetland, such as nitrogen retention, or both. 

3.3. Other Ecological Assessment Endpoints 

The GEAEs presented in this document are those that are thought to be currently 

generically useful in EPA and do not preclude the use of other endpoints. Other endpoints may 

be chosen because they reflect some particular environmental value associated with a site or held 

by a particular stakeholder or for some other reason they are particularly appropriate for a 

21
particular assessment (see Section 3.1). In addition, some endpoints that are not generically 

practical may be practical in a particular case because of peculiarities of the stressor or receptor, 

data availability, or availability of a model of the receiving system or because time and resources 

are available to assess a difficult endpoint. These additional assessment endpoints must meet the 

criteria in the EPA’s guidelines. 

3.4. Completing a List of Assessment Endpoints for a Specific Assessment 

When a list of potential assessment endpoints has been developed, it may be necessary to 

review the list and reduce it to those that are important to the decision. Because of the 

limitations of time and resources, it is often advisable to limit the list of assessment endpoints to 

those that are most relevant and susceptible. There is likely to be some redundancy in the 

endpoints. Kills of organisms imply immediate changes in population abundance that may 

influence community abundances. If population or community properties are important to the 

decisionmaker, they should be retained. However, if kills are sufficient to warrant action, the 

extrapolations to higher levels of biological organization may be unnecessary and those 

endpoints may be dropped as unnecessarily redundant. 

22
4. RECOMMENDATIONS FOR FURTHER PROGRESS 

The main purpose of this report is to improve ecological considerations within EPA by 

developing an initial set of generically useful ecological assessment endpoints (see Table 2-1). 

However, these initial assessment endpoints are based on existing policy and practice rather than 

on an evaluation of all the potentially useful ecological assessment endpoints that may exist for 

the Agency now or in the future. Therefore, readers of this report are encouraged to (1) develop 

and maintain a continual, open process for reviewing, amending, and creating new GEAEs and 

(2) establish a means of keeping track of the many rationales and precedents used for making 

ecological risk-based decisions throughout EPA. In particular, as the GEAEs are applied to 

ecological risk assessments, the experiences should be documented and published as case 

studies. The remainder of this chapter provides more discussion about these two 

recommendations and concludes with a method of how you, the reader, can contribute to EPA’s 

progress in this area by suggesting other useful assessment endpoints. Table 4-1 presents 

potential GEAEs for more immediate consideration by EPA. 

4.1. Develop and Support a Continual, Open Process for Reviewing, Amending, and 

Creating New GEAEs 

The initial GEAEs presented in this report include important ecological attributes to 

consider when conducting ecological assessments throughout EPA. However, the Agency 

should not remain static or constrain itself to these particular GEAEs. EPA should establish and 

maintain an adaptive and open process for reviewing and amending ecological assessment 

endpoints over time, as science and Agency experience evolve. Care must be taken so that new 

GEAEs are consistent with this document and the Agency’s ecological risk assessment 

guidelines. The process and frequency of these updates or reviews must be approved by Agency 

management. 

Both the technical panel and external peer reviewers of this document suggested that 

regular reviews of EPA’s generic ecological assessment endpoints are important and that fiveyear intervals would be appropriate for updating them. There is consensus that broad 

participation is also vital. Members of future review panels should represent as many 

programmatic, regional, and support offices of EPA as possible, and they should consider 

external input from other government agencies, nongovernment organizations, academia, the 

general public, and the private sector. 

23
Table 4-1. Potential GEAEs 

Entity Attribute 

Organism-level endpoints 

Organisms (in an assessment 

population or community) 

Physiological status (in addition to growth) 

Disease or debilitation (in additions to gross anomalies) 

Avoidance behavior 

Courtship behavior (e.g., birds) 

Migratory behavior (e.g., birds and salmonids) 

Nurturing and rearing behavior (e.g., nest abandonment) 

Population-level endpoints 

Assessment population Genetic diversity 

Community and ecosystem-level endpoints 

Assessment communities, 

assemblages, and ecosystems 

Trophic structure 

Energy flow 

Nutrient cycling (ecosystems in addition to wetlands) 

Nutrient retention 

Decomposition rates 

Sediment and material transport 

Area or function of estuaries and riparian ecosystems 

Resilience 

Vertical structure of plant communities 

Attributes that influence public health 

Landscape-level endpoints 

Assessment landscapes (of multiple 

populations, communities, assemblages, and 

ecosystems) 

Spatial pattern (random, clustered or uniform; dominance; 

contagion; contiguity or fragmentation; juxtaposition) 

4.2. Develop a Database to Document and Keep Track of New Rationales, Precedents, and 

Assessment Endpoints 

A readily accessible and searchable database of existing and new ecological assessment 

endpoints should be established and supported on a continual basis. This database could be for 

internal (and perhaps external) use and provide rationales and precedents (or histories) of how 

these ecological assessment endpoints have been used by EPA. For example, when a program or 

regional office finds scientific or societal justification for an ecological assessment endpoint, that 

office should consider it again in future assessments and share this knowledge with other offices 

throughout the Agency. Useful information could include how the ecological assessment 

endpoint affected decision making, whether some endpoints carry more weight than others, or 

whether they were ignored or too difficult to interpret or use. The technical panel recommends 

creating a centralized, web-based database for facilitating this process. 

24
4.3. Potential GEAEs for Future Consideration 

EPA is responsible for stating its mandates as clearly understood goals and assessment 

endpoints for ecological protection. As different stressors challenge our environment and our 

scientific understanding of ecosystems improves, new ecological assessment endpoints will need 

to be considered and incorporated into EPA’s mission. 

In Table 2-1, the technical panel 

recommends assessment endpoints that have 

some existing precedent or legal or regulatory 

basis for use within EPA. Such precedents, as 

presented in Appendix A, include treaties, 

statutes, regulations, judicial decisions, official 

memoranda, guidance or procedures, and other 

documentation. However, the technical panel 

remains concerned about otherwise valid and 

important ecological assessment endpoints being 

excluded from Table 2-1 and encourages users of 

this guidance to continually strive for further 

progress and innovation within the Agency to 

advance new and improved GEAEs. Therefore, 

on the basis of comments received from peer 

reviewers of this report as well as suggestions 

found in recent Agency publications (e.g., U.S. 

EPA 2002a), the technical panel also 

recommends the potential GEAEs presented in 

Table 4-1 for consideration by EPA scientists and 

managers. Note that some of these potential 

assessment endpoints are not entirely new, but 

rather are extensions the of the GEAEs listed in 

Table 2-1, and some may not yet satisfy the 

criterion of practicality, as defined in Section 1.3. 

We encourage EPA’s program and 

regional offices to regularly consider the GEAEs 

in Tables 2-1 and 4-1 and other potentially 

relevant assessment endpoints for purpose of 

guiding EPA’s evolving ecological mission. 

However, in order to keep GEAEs meaningful, 

Developing new assessment endpoints 

One suggestion for developing new 

assessment endpoints is to consider the 

following dimensions associated with 

ecological systems and whether they are 

addressed in Agency risk assessment 

activities: 

1. Levels of biological organization 

(e.g., potentially ranging from DNA to 

biomes). 

2. Spatial scale (e.g., ranging from 

local to global boundaries). 

3. Temporal scale (e.g., 

considerations of the timing, duration 

and/or frequency of biological activities 

or events). 

4. Magnitude (e.g., the total number 

of ecological entities present, impacted, 

or remaining with respect to a known 

baseline or presumption of what should 

be there). 

5. Taxonomic groups (i.e., beyond 

mammals, fish, and birds to other taxa 

such as amphibians, reptiles, 

invertebrates, bacteria, fungi, and 

flowering and nonflowering plants. 

6. Range of ecological properties 

(e.g., resiliency in ecosystems). 

The initial GEAEs presented in 

Table 2-1 incorporate or touch upon 

many of these dimensions, yet many 

other assessment endpoints could 

potentially be derived by increasing the 

range of just one of these dimensions or 

by integrating two or more of these 

dimensions in a new way. 

25
the Agency should consider maintaining a conservative approach toward adding new ones. This 

can be done by consistently applying the criteria established in this guidance and by paying close 

attention to the distinction between assessment endpoints and measures of effect (i.e., 

measurement endpoints). 

26
5. CONCLUSION 

The development of this document revealed that the laws, policies, and precedents for 

protecting attributes of ecological entities are numerous and diverse. They provide a strong basis 

for defining assessment endpoints at the organism, population, and community/ecosystem levels 

of organization. They are defined and organized in a consistent fashion in this report as GEAEs. 

GEAEs are widely applicable to various assessment scenarios and can provide a 

foundation for the development of endpoints for specific assessments during problem 

formulation. This set of GEAEs can be used by risk assessors and risk managers with the 

confidence that they are supported by established policies and precedents and thus will improve 

the scientific basis for ecological risk management decisions. 

Risk assessors and risk managers throughout the Agency are encouraged to track the 

rationales for making ecological risk-based decisions, thereby providing a basis for reviewing 

and updating these GEAEs in the future. 

27
APPENDIX A. SUPPORTING INFORMATION 

This appendix serves as a reference for those who need to know the basis for a particular 

GEAE defined in Section 2. The GEAEs have been divided into three categories of biological 

organization—organism, population, and community/assemblage/ecosystem—and a fourth 

category containing endpoints (critical habitats and special places) that are most easily described 

separately. Each category is introduced by general information about how the GEAEs in that 

category have been used by the Agency. Additional supporting information divided into two 

sections, is then provided for each GEAE. The first section is Laws, Regulations, and 

Precedents, which discusses the authorities that support the use of each GEAE by EPA and gives 

examples of Agency actions that provide a further basis for their use. The second section is 

Practicality, which discusses the availability of methods to estimate risks to the endpoint and 

their applicability in various risk assessment contexts. Because assessment endpoints are 

defined as valued properties of the environment (U.S. EPA, 1998a), public values associated 

with the GEAEs are discussed in broad terms in Appendix B. 

It should be noted that the specific laws and other policies cited below are not the only 

support for ecological endpoints. The many federal environmental laws and their implementing 

regulations provide a general mandate for environmental protection that goes far beyond the 

specific instances presented in this appendix. In particular, the National Environmental Policy 

Act of 1970 creates a broad mandate for federal agencies to protect and prevent degradation of 

the environment. Although nearly all environmental statutes refer to the environment as an 

entity to be protected, and many refer to more specific ecological entities such as fish, wildlife, 

and estuaries, few indicate an attribute to be protected or even the nature of the entity. In 

addition, terms are not necessarily used in a technical way. For example, the Clean Water Act 

refers repeatedly to “a balanced indigenous population of fish, shellfish and invertebrates.” 

Clearly, the phrase does not refer to a biological population, which is formed of members of one 

species. Further, when referring to fish, does the act mean fish at the level of organism, 

population, or assemblage or as a taxon? Given these ambiguities, the wording of the statutes 

must be interpreted to define endpoints. The primary source of support for the following 

interpretations is precedent. 

The precedents and other expressions of policy discussed below are a sample of those 

that have been used in assessments, guidance, protocols, and other Agency actions over the 

years. Although they are derived from particular laws and regulatory contexts, they may be 

interpreted as examples of what Congress and the Agency have meant by protecting the 

environment. For example, the Clean Air Act calls for specific protection of “national parks, 

national wilderness areas, national monuments, national seashores, and other areas of special 

28
national or regional natural, recreational, scenic, or historic value.” This requirement can be 

interpreted as a mandate to the Agency to protect those special areas from pollution, not just 

from the threats from air pollution that were brought to the attention of Congress. 

The following abbreviations and acronyms are used in this appendix: 

CAA Clean Air Act

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act

CFR Code of Federal Regulations

CITES Convention on International Trade in Endangered Species

CWA Clean Water Act

ESA Endangered Species Act

FIFRA Federal Insecticide, Fungicide, and Rodenticide Act

FR Federal Register

LC50 Median lethal concentration

LD50 Median lethal dose

NCP National Contingency Plan

NEPA National Environmental Policy Act

OSWER Office of Solid Waste and Emergency Response

PCB Polychlorinated biphenyl

RCRA Resource Conservation and Recovery Act

SSD Species sensitivity distribution

TSCA Toxic Substances Control Act

A.1. Organism-Level Endpoints 

Major EPA statutes such as the CAA, CWA, CERCLA, FIFRA, TSCA, and RCRA 

require that EPA consider and protect organism-level attributes or various taxa of organisms, 

including fish, birds, and plants and, more generally, animals, wildlife, aquatic life, and living 

things. The toxicity information that is available to EPA in administering these statutes is 

dominated by organism-level attributes such as mortality. Organism-level attributes tend to be 

more practical to measure or predict than attributes at higher levels of organization for most EPA 

assessments. Consequently, EPA’s ecological assessments historically have focused on 

organism-level endpoints. Note that these endpoints do not normally imply protection of each 

individual organism, but rather the protection of these critical attributes of organisms within 

assessment populations or communities. As will be described, however, certain special 

29
categories of organisms, such as endangered species and marine mammals, have been afforded 

protection on an individual basis. 

In ecological assessments, EPA considers 

organism-level effects in a variety of taxa. For 

example, tests required for pesticide regulation 

can include effects on survival, growth, and 

reproduction (GEAE #3) of aquatic 

invertebrates, fish, birds, mammals, and both 

terrestrial and aquatic plants. Effects on a 

similar range of taxa are considered under TSCA 

(Lynch et al., 1994; Zeeman et al., 1999) and in 

deriving water quality criteria under the CWA. 

Less commonly, other taxa, such as earthworms 

(e.g., at certain Superfund sites), honeybees (e.g., 

for certain pesticides), and reptiles and 

amphibians are considered . 

A.1.1. GEAE #1. Kills of Organisms 

Laws, Regulations, and Precedents: Kills 

The regulation of chemicals to prevent 

kills of organisms, in the absence of effects on 

populations or communities, has been sustained 

by federal courts. For example, the use of the 

pesticide diazinon on golf courses and sod farms 

was prohibited after documentation of 

widespread and repeated bird kills (U.S. EPA, 

1988a). Subsequently, EPA cited continuing 

bird kills as a factor in the agreement with 

pesticide manufacturers to phase out all outdoor 

residential uses of diazinon (U.S. EPA, 2001a). 

Bird kills were also the basis for phasing out 

most uses of another pesticide, granular 

carbofuran (U.S. EPA, 1991b; Houseknecht, 

1993). Kills of birds and other wildlife in oil 

pits are considered evidence of “imminent and 

Connections between organism and 

higher-level endpoints 

Not only are organism attributes 

potentially important in themselves, but 

they are also important because they are 

protective of higher-level attributes. That 

is, we commonly assume that if we 

protect important attributes of organisms 

in a population or community, the 

population and community attributes will 

be protected as well. EPA’s principles for 

ecological risk assessment and risk 

management at Superfund sites (U.S. 

EPA, 1999b) illustrate a common usage 

of organism-level endpoints at EPA: 

“Except at a few very large sites, 

Superfund ERAs [ecological risk 

assessments] typically do not address 

effects on entire ecosystems, but rather 

normally gather effects data on 

individuals in order to predict or postulate 

potential effects on local wildlife, fish, 

invertebrate, and plant populations and 

communities that occur or that could 

occur in specific habitats at sites.... 

Levels [of chemicals] that are expected to 

protect local populations and communities 

can be estimated by extrapolating from 

effects on individuals and groups of 

individuals using a lines-of-evidence 

approach.” 

When organism-level information is 

not sufficient, it may be necessary to 

assess higher-level attributes directly, by 

employing population or community 

models or measurements. 

substantial endangerment to the environment” under RCRA §7003 (U.S. EPA, 2003a). Fish kills 

30
have also been considered a concern by EPA; for example, Region 5 considers fish kills and 

other excess mortality to be obvious impacts under RCRA (U.S. EPA, 1994). 

Under FIFRA reporting requirements for adverse effects of pesticides (40 CFR Part 159), 

EPA categorizes kills (and other adverse incidents) involving multiple organisms as more severe 

events than single organism incidents and imposes additional reporting requirements on pesticide 

registrants for such events. More severe wildlife incidents are defined as those involving at least 

1000 individuals of a schooling fish species or 50 individuals of a nonschooling species; 200 

individuals of a flocking bird species, 50 individuals of a songbird species, or 5 individuals of a 

predatory species; or, for mammals, reptiles, and amphibians, 50 individuals of a relatively 

common or herding species or 5 individuals of a rare or solitary species. (Note that incidents 

involving numbers of organisms below these thresholds still must be reported, but the 

requirements are different than those for more severe incidents. Also note that these criteria do 

not apply outside FIFRA.) 

Practicality: Kills 

The likelihood of kills is relatively readily estimated using the common acute lethality 

tests that generate LC50s and LD50s. The number of species involved in kills may be estimated 

from SSDs of LC50s or LD50s, as in the calculation of the acute National Ambient Water 

Quality Criteria (U.S. EPA, 1985a; Posthuma et al., 2002). The occurrence of kills in the field 

may be readily observed in the cases of conspicuous organisms and open habitats, but in other 

cases, such as with small birds in crops or fence rows, kills may be unobserved and difficult to 

document. Recently, a model has been developed to predict the probability of bird kills for a 

particular use of a cholinesterase-inhibiting pesticide using SSDs of LD50s and field studies 

(Mineau, 2002). 

A.1.2. GEAE #2. Gross Anomalies of Organisms 

Laws, Regulations, and Precedents: Gross Anomalies 

Gross anomalies in birds, fish, shellfish, and other organisms are cause for public concern 

and have been the basis for EPA regulatory action and guidance. For example, crossed bills and 

other deformities in piscivorous birds are a basis for the proposed remediation of the PCBcontaminated sediments at the Fox River/Green Bay Superfund site (Wisconsin Department of 

Natural Resources, 2001; U.S. EPA, 1998b) and were a basis for the designation of the system as 

an Area of Concern by the Great Lakes National Program Office (U.S. EPA, 2001b). EPA 

actions to restrict the use of tributyltin as an antifoulant on boats (U.S. EPA, 1988b), as well as 

the restrictions imposed by the Organotin Antifouling Paint Control Act of 1988, were triggered 

by the observed induction of gross deformities in mollusks that threatened the marketability of 

31
oysters, reduced the fecundity of the deformed organisms, and suggested the potential for other 

effects. 

Natural resource damage regulations for CERCLA, the CWA, and the Oil Pollution Act 

include gross anomalies among the designated injuries (43 CFR §11.62(f)), and deformities, 

erosion, lesions and tumors in fish (DELT anomalies) are used in the biocriteria of many state 

water quality standards and in Agency guidance (Yoder and Rankin, 1995; U.S. EPA, 1996). 

Changes in development, which can be manifested in physical anomalies, have been identified as 

an environmental effect of regulatory concern under TSCA (U.S. EPA, 1983). 

Anomalies in plants and plant injuries have also been the basis for EPA action. For 

example, EPA established a secondary ambient air quality standard for ground-level ozone partly 

on the basis of visible foliar injury to commercial crops and natural vegetation, stating that 

“foliar injury is occurring on native vegetation in national parks, forests, and wilderness areas, 

and may be degrading the aesthetic quality of the natural landscape, a resource important to 

public welfare” (U.S. EPA, 1997b). EPA has also used visible injury of plants as a basis for 

regulating air emissions of aluminum reduction plants and sulfuric acid production units (U.S. 

EPA, 1994). 

Practicality: Gross Anomalies 

External gross anomalies are readily observed, as are some internal anomalies with 

external manifestations such as severe scoliosis or large tumors. Gross anomalies are commonly 

included in biological survey protocols for fish and in forest health surveys. They are also 

included as endpoint responses in some chronic tests of fish and birds. 

A.1.3. GEAE #3. Survival, Fecundity, and Growth of Organisms 

As discussed in Section A.1., EPA’s ecological assessments have considered effects on 

survival, fecundity, and growth in a variety of taxa. Although actions based on survival may be 

the most common, EPA has also made regulatory decisions on the basis of effects on fecundity 

and growth of organisms identified in ecological risk assessments. For example, the pesticide 

chlorofenapyr was not approved by EPA on the basis of Agency concerns over reproductive 

risks to birds. Additionally, federal statutes and other precedents confer special status on 

particular kinds of organisms: endangered and threatened species, marine mammals, bald and 

golden eagles, and migratory birds. The remainder of this section concentrates on the basis for 

the special status of these organisms within the organism-level endpoints. 

32
Laws, Regulations, and Precedents: Survival, Fecundity, and Growth 

Endangered and threatened species. The ESA protects threatened or endangered 

species from taking, which is defined as “to harass, harm, pursue, hunt, shoot, wound, kill, trap, 

capture, or collect, or to attempt to engage in any such conduct” (16 US Code, §1532, and 50 

CFR, parts 14, 17, and 23). Under the act, the term “species” includes “any subspecies of fish or 

wildlife or plants and any distinct population segment of any species of vertebrate fish or 

wildlife which interbreeds when mature.” The ESA states that it is “to be the policy of Congress 

that all Federal departments and agencies shall seek to conserve endangered species and 

threatened species” and that “Federal agencies shall cooperate with State and local agencies to 

resolve water resource issues in concert with conservation of endangered species” (16 US Code, 

§1531). Hence, the provisions of the ESA are applicable to EPA actions, and both the 

prohibition against harming individual members of threatened or endangered species and the 

affirmative obligation to conserve those species would seem to include toxic effects. 

Additionally, the CAA (§112) specifically requires EPA to prevent adverse effects to endangered 

species in regulating hazardous air pollutants. 

Like other federal agencies, EPA has published regulations and taken actions to protect 

endangered species. For example, EPA has consulted with the U.S. Fish and Wildlife Service 

and the National Marine Fisheries Service to prevent jeopardy to endangered species, as required 

by the ESA, for actions such as setting water quality standards and regulating pesticides. In 

these consultations, the attributes of concern have generally been survival, fecundity, and 

growth, although other attributes may be important in specific cases. The NCP specifies that the 

ESA is a federal “applicable or relevant and appropriate requirement” with which Superfund 

remedial actions should comply under CERCLA §121(d)(2)(A), and examples of Superfund 

ecological risk assessments that used endangered species as endpoints include the Asarco 

Tacoma site (chinook salmon and bull trout) (Hillman and Rochlin, 2001), the Metal Bank of 

America site (shortnose sturgeon) (Wentsel et al., 1999), and the Montrose, Iron Mountain Mine, 

Fort Ord and Monterey Marine Sanctuary, Camp Pendleton-Santa Margarita River, and Pearl 

Harbor sites (U.S. EPA, 1994). 

Marine mammals. The Marine Mammal Protection Act protects marine mammals from 

taking, which is defined as 

to harass, hunt, capture, or kill, or attempt to harass, hunt, capture, or kill any marine 

mammal....The term ‘harassment’ means any act of pursuit, torment, or annoyance which 

(I) has the potential to injure a marine mammal or marine mammal stock in the wild; or 

(ii) has the potential to disturb a marine mammal or marine mammal stock in the wild by 

causing disruption of behavioral patterns, including, but not limited to, migration, 

breathing, nursing, breeding, feeding, or sheltering. (US Code, §1362) 

33
Although the act does not specifically address toxic effects on marine mammals, the 

special protection afforded these species by the act implies a particular concern for their wellbeing. Also, the law clearly protects properties of marine mammals at the organism level. 

As with threatened and endangered species, the NCP specifies that the Marine Mammal 

Protection Act is a federal “applicable or relevant and appropriate requirement” with which 

Superfund remedial actions should comply under CERCLA, §121(d)(2)(A), and it cites marine 

mammals as examples of specific natural resources to be protected under CERCLA, Part 101, 

§16. 

Bald and golden eagles. Prohibited actions under the Bald and Golden Eagle Protection 

Act include to “take, possess, sell, purchase, barter, offer to sell, purchase or barter, transport, 

export or import, at any time or in any manner any bald eagle commonly known as the American 

eagle or any golden eagle, alive or dead, or any part, nest, or egg thereof of the foregoing 

eagles...” (16 US Code, §668). To take, as defined by regulation, includes “to pursue, hunt, 

shoot, wound, kill, trap, capture, or collect, or attempt to pursue, hunt, shoot, wound, kill, trap, 

capture, or collect” bald eagles or golden eagles, including any “part, nest, or egg of such 

bird[s]” (50 CFR §10.12). 

Deaths of bald eagles due to secondary poisoning were an endpoint in EPA’s assessment 

of granular carbofuran (U.S. EPA, 1991b), which led to the phaseout of most uses of this 

pesticide. Also, EPA’s ecological risk assessment for PCBs in the Hudson River included 

survival, growth, and reproduction of piscivorous birds as an assessment endpoint, with the bald 

eagle selected as one of the representative species of piscivorous birds (U.S. EPA, 2000). 

Birds. The Migratory Bird Treaty Act of 1918 prohibits or regulates a number of 

activities, including pursuing, taking, hunting, capturing, killing, possessing, selling, 

transporting, or purchasing migratory birds, including their eggs and nests (16 US Code, §703). 

This act, based originally on a treaty between the United States and Great Britain (including 

Canada), has since been extended by migratory bird conventions with Mexico, Japan, and the 

Soviet Union. Because nearly all species of birds native to the United States are protected by the 

act (U.S. Fish and Wildlife Service, 2001), the endpoint may be assumed to apply to native birds 

in general. Although the Migratory Bird Treaty Act does not specifically address toxic effects 

on birds, the special protection afforded these species by the act implies a particular concern for 

their well-being. Also, the law clearly protects birds at the organism level. Furthermore, by 

Executive Order 13186, all federal agencies are required to “support the conservation intent of 

the migratory birds conventions by integrating bird conservation principles, measures, and 

practices into agency activities and by avoiding or minimizing, to the extent practicable, adverse 

impacts on migratory bird resources when conducting agency actions” and to “prevent or abate 

34
the pollution or detrimental alteration of the environment for the benefit of migratory birds, as 

practicable” (Clinton, 2001). 

EPA policies and precedents affirm the use of survival, growth, and reproduction of birds 

in ecological assessments. The NCP specifies that the Migratory Bird Treaty Act is a federal 

“applicable or relevant and appropriate requirement” with which Superfund remedial actions 

should comply under CERCLA §121(d)(2)(A), and examples of Superfund ecological risk 

assessments that used birds as endpoints include the Baird and McGuire site (survival and 

reproduction of songbirds) (Menzie et al., 1992) and the United Heckathorn site (reproductive 

effects on birds) (Wentsel et al., 1999). EPA’s ecological risk assessment for PCBs in the 

Hudson River included survival, growth, and reproduction of insectivorous birds, waterfowl, and 

piscivorous birds as assessment endpoints (U.S. EPA, 2000). EPA regulations authorize the 

Agency to require pesticide registrants to submit tests on avian mortality and impaired avian 

reproduction caused by pesticides. Results from these tests, in conjunction with other available 

information, are used by EPA in making pesticide registration decisions. Also, EPA’s 

involvement in bird conservation initiatives such as Partners in Flight and the North American 

Bird Conservation Initiative provides further support for using birds in assessment endpoints 

(U.S. EPA, 2002b). 

Practicality: Survival, Fecundity, and Growth 

Because the vast majority of standard toxicity tests determine effects on the survival, 

fecundity, and growth of organisms, direct toxic effects on this endpoint are readily predicted. In 

addition, extrapolation models are available that can estimate effects on this endpoint for 

particular organisms and exposure routes of concern on the basis of tests conducted on other 

species, life stages, or exposure durations or routes. 

It is rarely possible to obtain toxicity data for threatened and endangered species, but 

SSDs, intertaxa regressions, or other interspecies extrapolation models should serve to estimate 

effects of these species (Suter, 1998; Posthuma et al., 2002). EPA research has confirmed that 

endangered species are not inherently more sensitive than other species to toxic effects 

(Sappington et al., 2001), although, from a population standpoint, they may be at greater risk due 

to their low abundance. 

Effects on marine mammals are relatively difficult to observe in the field. However, dieoffs of pinnipeds and cetaceans are readily observed when their conspicuous carcasses appear on 

beaches. The toxicology of marine mammals is poorly known, and, for obvious reasons, marine 

mammals are not included in routine toxicity testing. However, effects on all mammals are 

routinely estimated from tests performed with rodents. Exposure of marine mammals is also 

35
poorly known and is not routinely estimated, even though these mammals can accumulate high 

levels of persistent pollutants. 

Eagles are highly conspicuous, and dead or debilitated eagles are more likely to be 

reported by the public than are most birds. In addition, federal, state, and private organizations 

monitor eagles at various scales. Toxic effects on eagles may be predicted from standard avian 

toxicity tests or, more confidently, from tests with kestrels, with avian allometric models used to 

extrapolate toxicity results to eagles. 

In general, the biology of birds is well known, and well-developed methods exist for 

surveying bird populations and communities. Both acute and chronic test protocols for birds are 

available, and avian toxicity data are available for most pesticides and many other chemicals. 

However, because birds are highly mobile, often migratory, and often territorial, it is usually 

difficult to demonstrate chronic effects on these organisms in the field. 

A.2. Population-Level Endpoints 

As described in Section A.1., most environmental statutes authorizing EPA activities call 

for protection of a diverse array of organisms. These statutes generally can be inferred to protect 

population-level endpoints in addition to organism-level endpoints, even if populations are not 

specifically cited by law. EPA’s principles for ecological risk assessment and risk management 

at Superfund sites exemplify EPA’s concern about population-level endpoints: “Superfund’s 

goal is to reduce ecological risks to levels that will result in the recovery and maintenance of 

healthy local populations and communities of biota” (U.S. EPA, 1999b). 

Predicting population-level impacts generally is not as straightforward as estimating 

organism-level effects and, as a result, explicit estimates of population effects are less common 

in EPA ecological assessments. Adverse effects on organisms are often inferred to indicate risk 

to populations and hence a cause for concern under certain EPA programs, such as Superfund. 

Similar inferences are made for chemical reviews under TSCA. In examining environmental 

effects of concern under TSCA, an EPA position paper reviewed a number of statutes spanning 

the period of 1785 to 1978 to determine society’s environmental values (U.S. EPA, 1983). EPA 

concluded that such laws were passed to prevent any reduction, degradation, or loss in the 

quality, quantity, or utility of a resource that is valued by the public. It also concluded that 

chemicals could adversely affect these resources by causing an undesirable change in the 

population structure of a species by affecting rates of mortality, reproduction, or growth and 

development. Thus, organism-level attributes such as mortality can be inferred to affect 

population-level attributes valued by society. Less commonly, EPA prepares quantitative 

estimates of population effects based on organism-level effects or other information. 

36
Population-level endpoints have been assessed at EPA for commercially or recreationally 

valuable species such as fish, birds, and shellfish. 

A.2.1. GEAE #4. Extirpation of an Assessment Population 

Extirpation can be viewed as an extreme case of a change in abundance or production of 

an assessment population, and thus its selection is supported by the factors cited in Section 

A.2.2. Additionally, extirpation of an assessment population may have qualitatively more 

significant impacts on ecological function and environmental values than just reduction in the 

size of the assessment population, as reflected in an alternative term for this population attribute: 

functional extinction. 

Laws, Regulations, and Precedents: Extirpation 

Several EPA precedents exist for assessing population extirpation. For example, EPA 

examined the likelihood of extirpation of fish populations in northeastern lakes under the acid 

deposition program and vetoed a permit for a dam and reservoir project under Section 404 of the 

CWA, in part on the basis of the projected extirpation of populations of birds of special interest 

(U.S. EPA, 1994). Absence of a species normally occurring in the habitat has been used as 

evidence of ecological risk at Superfund sites. Where designated aquatic life uses have been 

specified in state water quality standards, extirpation of a naturally occurring species may be 

considered as evidence that the waterbody is not attaining its designated uses. 

Practicality: Extirpation 

Field observations to determine whether a species is present usually are not difficult to 

conduct, but ease of observation depends upon the species, and care must be taken in interpreting 

results. Failure to observe a species that is expected to occur in low numbers even in the absence 

of stressors, that is subject to substantial natural fluctuations in abundance, or that is 

inconspicuous may not be indicative of extirpation. Demonstrating extirpation at a site also 

requires evidence that the species was formerly present. 

In some cases, risk of extirpation can be inferred from toxicity data. Very high exposure 

in the field in comparison to exposures where toxic effects have been observed in laboratory 

tests suggests a high likelihood of extirpation and, conversely, very low exposure implies that 

extirpation is unlikely. Population modeling (such as population viability analysis) or ecosystem 

modeling may be required to estimate the likelihood of extirpation in cases where exposure is 

lethal to only a portion of individuals, where effects on reproduction are expected but limited, or 

where effects are indirect. Population modeling typically requires species-specific data on 

parameters not routinely available in ecological risk assessment, such as age-specific 

37
reproduction rates. However, population models are available and well developed and have been 

used to predict extirpation, particularly of fisheries (Barnthouse, 1993; Pastorok et al., 2002). 

See also Section A.2.2. 

A.2.2. GEAE #5. Abundance of an Assessment Population 

Laws, Regulations, and Precedents: Abundance 

Abundance is the most common population-level endpoint considered by EPA. On 

occasion, EPA evaluated population models to explore effects on abundance by chemicals 

regulated under TSCA. For example, EPA explored the risks of chloroparaffins to a rainbow 

trout population using a projection matrix model (U.S. EPA, 1993a). Maintenance of 

populations of piscivorous birds and mammals was the ecological assessment endpoint for the 

Mercury Report to Congress (U.S. EPA, 1995). 

Additionally, more than 25 estuaries have been selected as national estuaries by EPA, as 

authorized by the CWA. Restoring or protecting populations and production of fish and shellfish 

for commercial and recreational use typically is among the goals of individual national estuary 

programs. Similarly, a goal of the Chesapeake Bay Program (a partnership among EPA and the 

states adjoining the bay) is restoring, protecting, and enhancing fish and shellfish, with measures 

including populations of oysters and priority migratory fish species such as striped bass. 

Practicality: Abundance 

Changes in population abundance may be predicted using conventional toxicity data with 

statistical extrapolation models and population models (Suter, 1993; Pastorok et al., 2002). This 

approach can produce reasonable results, and has been validated in controlled conditions. For 

example, Kuhn et al. (2001) compared a mysid shrimp population prediction from a stage-based 

projection matrix model with a 55-day laboratory population study involving shrimp exposed to 

p-nonylphenol. The population model was able to project within a few micrograms per liter the 

concentration where population-level effects would begin to occur (16 :g/L projected from the 

model vs. 19 :g/L measured from the assay). Although such projection matrix models are 

practical, they require more effort than is normally applied to routine ecological risk 

assessments. 

Population abundance may also be estimated using individual-based population models 

or, as discussed in Section A.3, ecosystem models. Measurement of population abundance in the 

field may be easy (e.g., for flowering plants) or difficult (e.g., for pelagic cetaceans). However, 

even when measurement is easy, distinguishing changes in abundance may be quite difficult due 

to temporal variance, and distinguishing differences from reference populations may be difficult 

due to differences in habitat quality as well as stochastic variance. The literature in ecology 

38
concerning the measurement and monitoring of various plant and animal populations is 

voluminous. 

A.2.3. GEAE #6. Production of an Assessment Population 

Laws, Regulations, and Precedents: Production 

Much of the support for GEAE #5, abundance of an assessment population, also applies 

to this endpoint. For example, the CWA sets a national goal of “protection and propagation of 

fish, shellfish, and wildlife,” which implies both abundance and production, and efforts under the 

National Estuary and Chesapeake Bay programs to protect resource species involve both 

abundance and production. Additionally, numerous federal laws and treaties have the purpose of 

maintaining or increasing the production of game birds and mammals, commercial fish, and 

timber species. Examples include the Migratory Bird Hunting Stamp Act (48 Stat. 451), 

Wildlife Restoration Act (50 Stat. 917), Fish Restoration and Management Act (64 Stat. 430), 

Convention on Great Lakes Fisheries (6 UST 2836), and Fish and Wildlife Act of 1956 (70 Stat. 

1119). Relevant provisions include requirements to “develop measures for maximum 

sustainable production of fish” (70 Stat. 1119) and “make possible the maximum sustained 

productivity of Great Lakes fisheries” (6 UST 2836). 

Prevention of adverse effects to public welfare, including (but not limited to) effects on 

soils, water, crops, vegetation, animals, and wildlife is mandated under Section 108 (§109) of the 

CAA (National Ambient Air Quality Standards). EPA has included production of an assessment 

population, among other endpoints, as an indicator of public welfare. For example, EPA revised 

the secondary ozone standard to provide increased protection against ozone-induced effects on 

vegetation, such as agricultural crop loss and damage to forests (U.S. EPA, 1997b). Also, EPA 

regulations authorize the Agency to require pesticide registrants to submit tests on pesticide 

effects on plant mortality and plant growth inhibition. Results from these tests, in conjunction 

with other available information, are used by EPA in making pesticide registration decisions. 

Changes in production of specific legume species were endpoints in a TSCA assessment of 

release of recombinant rhizobia (McClung and Sayer, 1994; Orr et al., 1999). 

Practicality: Production 

Plant production is relatively easily and commonly measured in the field. Production of 

animals is more difficult to measure in the field, but well-developed techniques exist and are 

commonly employed for fisheries, game species, and pest insects. Toxic effects on production 

may be estimated from chronic tests that include survival, fecundity, and growth. The combined 

effects on population production of these organismal responses may be estimated using 

population or ecosystem models. 

39
A.3. Community and Ecosystem-Level Endpoints 

Abundant statutory and regulatory 

support exists for environmental protection at 

levels above the organism and population levels. 

This support stems both from the recognition that 

maintaining particular organisms of concern 

involves their preserving surrounding 

environment and from appreciation for the 

ecosystem as a whole. In the case of direct 

assessment of community-level endpoints, taxa 

richness (GEAE #7) and abundance (GEAE #8) 

are the two most commonly addressed attributes. 

Production (GEAE #9) of plant communities (as 

with production of plant populations, GEAE #6) 

has also been considered by EPA in some cases. 

Example of support of community/ 

ecosystem-level endpoints: Superfund 

EPA’s principles for ecological risk 

assessment and risk management at 

Superfund sites state that “Superfund’s 

goal is to reduce ecological risks to levels 

that will result in the recovery and 

maintenance of healthy local populations 

and communities of biota.” Community 

effects can either be measured directly 

(e.g., as in benthic species diversity) or 

estimated indirectly (e.g., from toxicity 

tests on individual species) (U.S. EPA, 

1999b). 

Perhaps the simplest and most widely used ecosystem-level endpoint is the area (extent) 

of an ecosystem (GEAE #10). Physical structure (GEAE # 12) is also commonly used as an 

endpoint in assessing aquatic ecosystems. The authors found little precedent at EPA for using 

attributes based on ecosystem function, such as primary production, energy flow, total biomass, 

and nutrient cycling, except in the case of wetland ecosystems (GEAE #11). Such endpoints 

may have limited use to date, because they are somewhat abstract and not as directly linked to 

management values as other endpoints. Several such endpoints are listed in Table 4-1 as 

potential GEAEs for future EPA consideration. 

Further details about the support for community- and ecosystem-level endpoints are 

presented in this section in two ways. First, support spanning multiple attributes of 

community/ecosystem-level GEAEs is described for four general categories of ecosystems for 

which significant precedent exists: aquatic ecosystems, wetlands, coral reefs, and 

endangered/rare ecosystem types. Next, supporting information is presented for each of the six 

community/ecosystem-level GEAEs. 

Aquatic Ecosystems 

To date, the most common application of community- and assemblage-level endpoints at 

EPA has been to aquatic communities, particularly fish and macroinvertebrates. Section 

101(a)(2) of the CWA calls for an interim goal of water quality that provides for the protection 

and propagation of fish, shellfish, and wildlife. Section 304(a) of the Water Quality Act of 1987 

directs EPA to develop and publish water quality criteria and information on 

40
methods—including biological monitoring and assessment methods—that assess the effects of 

pollutants on the aquatic community. Aquatic community components and attributes addressed 

include “biological community diversity” and “productivity.” Taxa richness (GEAE #7) and 

abundance (GEAE #8) of species or trophic groups of fish and macroinvertebrate communities 

are used in the biocriteria of many states and in Agency guidance (Yoder and Rankin, 1995; U.S. 

EPA, 1996, 1999c). 

Potential community-level impacts also have been inferred and considered a basis of 

concern by EPA programs, based on organism-level responses. The U.S. Ambient Water 

Quality Criteria for Protection of Aquatic Life are based on SSDs, with the criteria set at the fifth 

percentile (U.S. EPA, 1985a); hence, they can be interpreted as protecting at least 95% of the 

species in a community. The assessment community is also commonly used in EPA programs 

under TSCA. The Quotient Method is typically applied to the most sensitive organismal 

response, as well as uncertainty factors, to infer effects on a community. Organisms are chosen 

to represent a variety of taxonomic groups. 

Ecosystem models are particularly useful for assessing secondary (indirect) effects of 

toxicants on community properties (Bartell et al., 1992; Pastorok et al., 2002). Models have 

been used to explore community-level effects, as in the case of evaluating the primary and 

secondary effects of chloroparaffins to top predator fish (Bartell, 1990; U.S. EPA, 1993a). 

Although there are relatively few examples of application of ecosystem models to the regulation 

of chemicals, generic models such as AQUATOX can serve to illustrate how direct and indirect 

effects propagate through ecosystems (U.S. EPA, 2003b). 

Wetlands 

The CWA forms the primary statutory basis for protection of wetlands and, thereby, the 

area (GEAE #10) and function (GEAE #11) of wetland communities/ecosystems. In meeting the 

CWA’s objective of restoring and maintaining the integrity of the nation’s waters, under Section 

404 of the act, wetlands are considered waters of the United States and are protected from 

discharge of dredged and fill material through a permit program jointly administered by the U.S. 

Army Corps of Engineers and EPA. Wetlands are defined for regulatory purposes as areas that 

are inundated or saturated by surface or ground water at a frequency and duration sufficient to 

support—and that under normal circumstances do support—a prevalence of vegetation typically 

adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, 

and similar areas (33 CFR §328.3 [b]). The CWA provides authority for the Corps to require 

permit applications to avoid and minimize wetlands impacts and requires EPA to develop, in 

coordination with the Corps, the criteria used for Section 404 permit decisions. When damages 

41
to wetlands are unavoidable, the Corps can require permitees to provide compensatory 

mitigation. 

Additionally, Executive Order 11990, Protection of Wetlands, states that “Each agency 

shall provide leadership and shall take action to prevent the destruction, loss or degradation of 

wetlands and to preserve and enhance natural and beneficial values of wetlands in carrying out 

the agency’s responsibilities” (Carter, 1977). As an extension of this order, President George H. 

W. Bush in 1989 and succeeding presidents have adopted a national policy of no net loss of 

wetlands in recognition of the significance of wetland areas and their ecological functions. The 

1972 Coastal Zone Management Act also calls for the protection of coastal wetlands. 

EPA has prepared various regulations and guidance documents supporting the wetlands 

protection goals of the CWA and Executive Order 11990. For example, “Guidelines for 

Specification of Disposal Sites for Dredged or Fill Material” (40 CFR, Part 230, Subpart E) 

recommends consideration of potential impacts on special aquatic sites, including wetlands, 

referencing changes that result in loss of wetland status due to permanent flooding or conversion 

to dry land as well as loss of functions of water purification, water storage, and provision of 

wetland habitat. 

The large number of Superfund sites located in or adjacent to wetlands has lead EPA’s 

policy and emphasis toward a greater concern regarding the impact of contamination from these 

sites on the extent and ecological functions of wetlands. OSWER highlights the importance of 

wetlands protection in the directive, “Policy on Floodplain and Wetland Assessment for 

CERCLA Action” (U.S. EPA, 1985b). Under this policy, Superfund action should meet the 

substantive requirements of Executive Order 11990 as well as the those of the Floodplain 

Management Executive Order (E.O. 11988). Section 404 of the CWA is also considered a 

federal “applicable or relevant and appropriate requirement” with which Superfund remedial 

actions should comply under CERCLA Section 121(d)(2)(A). Other Superfund policies that 

involve consideration or protection of wetlands include the Hazard Ranking System (U.S. EPA, 

1990a, 1992a), the Superfund removal process guidance (U.S. EPA, 1992b), a Memorandum of 

Agreement between EPA and the U.S. Department of Army (U.S. EPA, 1990b), and the OSWER 

directive, “Controlling the Impacts of Remediation Activities In or Around Wetlands” (U.S. 

EPA, 1993c). 

EPA’s “Procedures for Implementing the Requirements of the Council on Environmental 

Quality on the National Environmental Policy Act” (40 CFR §6.108) singles out wetlands by 

stating that “if the proposed action may have significant adverse effects on wetlands” an 

environmental impact statement is required. EPA’s regulations for State and Local Assistance 

(40 CFR, Part 35, Appendix A to Subpart H) require that project proposals demonstrate 

compliance with Executive Order 11990. 

42
Coral Reefs 

At present, coral reefs have not attained the same legal and regulatory stature under EPA 

programs as have wetlands, perhaps in part because few EPA actions involve coral reefs. 

However, support for their protection has been increasing in recent years. Taxa richness (GEAE 

#7) and area (GEAE #10) are the attributes of coral reef communities/ecosystems most 

commonly targeted for assessment and protection. Executive Order 13089 established special 

protection for coral reefs (Clinton, 1998). In particular, “All Federal agencies...shall...utilize 

their programs and authorities to protect and enhance the conditions of such ecosystems.” This 

Executive Order names the EPA Administrator as a member of the Coral Reef Task Force, which 

is responsible for implementing the order. An EPA memorandum to the field specifically applies 

the order to EPA’s responsibilities under Section 404 of the CWA, Sections 102 and 103 of the 

Marine Protection and Sanctuaries Act, and Section 307 of the Coastal Zone Management Act 

(Fox and Westphal, 1999). The order is also considered a federal “applicable or relevant and 

appropriate requirement” with which Superfund remedial actions should comply under CERCLA 

Section 121(d)(2)(A). 

“Guidelines for Specification of Disposal Sites for Dredged or Fill Material” (40 CFR, 

Part 230, Subpart E) recommend consideration of potential impacts on special aquatic sites, 

including coral reefs. The guidelines refer to loss of productive colonies and subsequent loss of 

coral-dependent species. 

Diversity is the only ecological attribute defined as a value of coral reefs in the National 

Action Plan to Conserve Coral Reefs (U.S. Coral Reef Task Force, 2000). A practical 

operational definition of that attribute is taxa richness. This document also mentions “shoreline 

protection, areas of natural beauty, recreation and tourism, and sources of food, pharmaceuticals, 

jobs, and revenues” as services of coral reefs. These services could be protected by preserving 

the area and taxa richness of coral reefs. 

CITES, to which the United States is a party, restricts international trade in corals and 

other reef organisms. All coral reefs in Florida are protected by either the U.S. or the state 

government. Other specifically protected reef communities are found in Puerto Rico, Hawaii, 

the U.S. Virgin Islands, Guam, Northern Marianas, and American Samoa. 

Endangered or Rare Ecosystems Types 

Support for the protection of endangered and rare ecosystems (particularly in the case of 

terrestrial ecosystems) is less extensive and more indirect than it is for the classes of 

communities/ecosystems described above, but it can be identified in a variety of programs. Area 

(GEAE #10) is the primary attribute assessed for these ecosystems. Additionally, note that 

inherent in the definition of the area of endangered and rare ecosystems may be attributes such as 

43
taxa richness (GEAE #7) and abundance (GEAE #8), and, consequently, the loss of these 

attributes could constitute loss of area of the ecosystem type as it is converted to a different 

ecosystem type. 

Several lines of support for protecting endangered and rare ecosystems are apparent in 

Superfund programs. The NCP specifies that, “evaluations shall be performed to assess threats 

to the environment, especially sensitive habitats” (emphasis added) (U.S. EPA, 1989). The 

Hazard Ranking System for Superfund (U.S. EPA, 1990a) gives as an example of “sensitive 

environments,” “particular areas, relatively small in size, important to maintenance of unique 

biotic communities.” The Superfund removal process guidance (U.S. EPA, 1992b) recommends 

that the On-Scene Coordinator undertake special considerations for actions that include sensitive 

ecosystems, which may be interpreted as calling for protection of endangered or rare ecosystem 

types. 

Other EPA programs also consider endangered ecosystems. For example, the protocol 

for screening-level ecological risk assessment for hazardous waste combustion facilities calls for 

special consideration of areas having unique and/or rare ecological receptors and natural 

resources (U.S. EPA, 1999a). EPA Regions 4, 5, 6 and the Great Lakes Program Office are 

developing approaches for identifying high-quality areas (critical ecosystems) for enhanced 

environmental protection and restoration. EPA Region 4 has been involved in the development 

of the Southeastern Ecological Framework as a decision support tool useful in integrating 

program resources for protecting and sustaining ecological processes. 

EPA Region 5 is also developing an approach for prioritizing and targeting high-quality 

areas in the Midwest (Mysz et al., 2000). Two of the criteria for identifying these areas, also 

called “critical ecosystems,” are (1) the presence of an indigenous ecosystem and biological 

community types (used as an indicator of relative ecological diversity), and (2) the numbers and 

rarity of native species and natural features (used as indicators of surviving relict native 

ecosystems). 

In addition, the EPA Great Lakes program, in collaboration with Environment Canada, 

has developed Biodiversity Investment Areas as natural areas along the Great Lakes shoreline 

whose high ecological value warrant exceptional attention to protect them from degradation. 

EPA Region 6 is using a GIS screening tool to assist in prioritizing ecological areas of concern 

for programs such as NEPA (Osowski et al., 2001). 

In carrying out its responsibilities for reviewing environmental impact statements under 

NEPA, EPA has developed guidance that calls for special attention to human activities in 

imperiled ecosystems and identifies mitigation measures to reduce adverse impacts (U.S. EPA, 

1993b). Approximately a dozen “principal habitats of concern” were identified within each of 

six major U.S. habitat types. Ecological concerns raised by EPA to other federal agencies in 

44
review of NEPA documents have included impacts to endangered or rare ecosystems (U.S. EPA, 

1994). 

A.3.1. GEAE #7. Taxa Richness of Assessment Communities, Assemblages, and 

Ecosystems 

Laws, Regulations, and Precedents: Taxa Richness 

As described in Section A.3., the most extensive support for use of this endpoint at EPA 

comes from measures to assess and protect the taxa richness of aquatic communities as part of 

water quality protection programs under the CWA. Use of taxa richness as an attribute can be 

inferred by programs under TSCA and other statutes to assess risks to a range of species across 

an aquatic community. Aquatic community composition is presented as an example of an 

assessment endpoint in Superfund ecological risk assessment guidance (U.S. EPA, 1997c), and 

community diversity or species richness is a generic endpoint for ecological risk assessments of 

hazardous waste combustors (U.S. EPA, 1999a). Support for taxa richness of coral reef 

communities/ecosystems is also described in Section A.3. 

EPA regional offices have considered the effects of federal projects on species diversity 

in decisions under NEPA, such as in an assessment of the impacts of the loss of bottomland 

hardwood forest on species composition of the wildlife community due to levee construction 

(U.S. EPA, 1994). 

Practicality: Taxa Richness 

Species or taxa richness is the simplest, least controversial, and most easily interpreted 

expression of community diversity. Changes in taxa richness are readily observed in standard 

biological surveys. If it is assumed that significant toxic effects are likely to result in local 

extirpation of a species, changes in taxa richness may be predicted using SSDs or regression 

models that relate all species of a community or assemblage to a test species. If indirect effects 

are expected to result in the loss of species, ecosystem models may be used to predict species 

losses. 

In the case of coral reefs, the taxa richness of corals are relatively easily determined. The 

taxa richness of some other assemblages (e.g., fishes and sessile noncoral invertebrates) is also 

practical to determine. Methods for assessing the condition of coral reefs are discussed in 

Jameson et al. (1998). Prediction of the effects of pollutants on coral reefs is difficult due to the 

paucity of toxicological information for corals. 

45
A.3.2. GEAE #8. Abundance of Assessment Communities, Assemblages, and Ecosystems 

Laws, Regulations, and Precedents: Abundance 

This endpoint shares with GEAE #7 the support described in Section A.3 for aquatic 

communities. Abundance of fish and macroinvertebrate taxa and trophic groups in sampled 

communities is used in the water quality biocriteria of many states and in Agency guidance. 

Community abundance can be inferred to be an element of ambient water quality standards and 

of chemical evaluations under TSCA. Aquatic community composition (including a metric 

describing abundance) is presented as an example of an assessment endpoint in Superfund 

ecological risk assessment guidance (U.S. EPA, 1997c). 

Practicality: Abundance 

Abundance of communities or assemblages, as a whole or by species, taxon, or trophic 

group, is available from most routine biological surveys. Although one can readily infer from 

standard toxicity tests that some changes in abundance are likely to occur, they are difficult to 

predict quantitatively. As discussed in Section A.3, community properties may be estimated 

from standard toxicity test data using ecosystem models. 

A.3.3. GEAE #9. Production of Assessment Communities, Assemblages, and Ecosystems 

Laws, Regulations, and Precedents: Production 

This endpoint shares a basis in laws, regulations, and precedents with GEAE #6, 

production of plant populations, through FIFRA, TSCA, and CAA programs. For example, the 

secondary ambient air quality standard established by EPA to protect public welfare for groundlevel ozone (U.S. EPA, 1997b) cites growth and yield reductions in tree seedlings and mature 

trees and impacts on forest stands and community structure due to these reductions. 

Superfund directives and guidance identify plant production, such as productivity of 

wetlands vegetation, as candidate assessment endpoints (Environmental Response Team, 1994a, 

b, c, d). Community productivity and, in particular, herbaceous plant productivity, is a generic 

endpoint for ecological risk assessments of hazardous waste combustors (U.S. EPA, 1999a). 

EPA actions to control acid rain and its precursors have been based on concerns over the damage 

to high-elevation forests—among other effects—attributed to acid rain. 

As stated in Section A.3., the CWA (§101(a)(2)) calls for an interim goal of water quality 

that provides for the protection and propagation of fish, shellfish, and wildlife. Section 304(a) of 

the act also lists effects of pollutants on plant life and on rates of eutrophication (excessive plant 

production due to nutrient pollution) as factors to consider in establishing pollutant limits. 

Eutrophication has been the basis for many federal and state regulatory actions and voluntary 

control programs, including the establishment of total maximum daily loads (TMDLs) for 

46
nutrients (U.S. EPA, 1999d), controls on nutrient discharges from sources such as publicly 

owned treatment works and confined animal feeding operations, and restrictions on phosphorus 

in detergents. 

Practicality: Production 

Eutrophication has long been a major concern of environmental managers, particularly 

with respect to sewage outfalls, so the models for predicting effects of nutrient additions are 

relatively well developed. Similarly, studies of fertilizer addition to crops, pastures, and 

commercial forests are numerous and provide a good basis for predicting the effects of terrestrial 

nutrient additions on plant production. In addition, methods for measuring plant production are 

well developed for both terrestrial and aquatic communities. Protocols for testing toxic effects 

on terrestrial and aquatic plants focus on various measures of production. However, toxicity data 

are less abundant for plants than for animals. 

A.3.4. GEAE #10. Area of Assessment Communities, Assemblages, and Ecosystems 

Laws, Regulations, and Precedents: Area 

The most extensive support for use of community/ecosystem area as a GEAE at EPA 

involves protection of wetlands. As discussed in Section A.3, the CWA affords special 

protection to wetlands, and a number of EPA programs reflect this emphasis. Within the 

Superfund program, for example, unavoidable impacts to on-site and adjacent wetland resources 

from current or potential exposure to hazardous substances and from implementation of select 

response actions are addressed within the Record of Decision for that site. Records of Decision 

for the New London Submarine Base in New London, Connecticut (U.S. EPA, 1998c), Loring 

Air Force Base in Limestone, Maine (U.S. EPA, 1997d), and Pease Air Force Base in 

Portsmouth/Newington, New Hampshire (U.S. EPA, 1997e) include remedies involving 

compensatory wetland mitigation. Mitigation actions are tracked by long-term monitoring plans 

and restoration efforts are monitored over a specified time period to ensure success. 

Efforts to assess and to control risks to coral reefs—and to rare/endangered ecosystems 

generally—also serve as precedents for the use of area as a GEAE (see Section A.3), although 

these programs are not currently as extensive at EPA as are those for wetlands. 

Practicality: Area 

Wetlands are classified and mapped by the National Wetlands Inventory of the U.S. Fish 

and Wildlife Service, but determination of wetland boundaries at a given site may be difficult, 

particularly in areas of low topographic relief. The 1987 Corps of Engineers Wetlands 

Delineation Manual (Environmental Laboratory, 1987) is the current federal delineation manual 

47
used in the CWA Section 404 regulatory program for the identification and delineation of 

wetlands. Most effects on wetland area are readily predicted or observed, because they occur 

due to processes such as dredging, filling, draining, or inundation. 

The area of coral reef is relatively easily determined. Methods for assessing the 

condition of coral reefs are discussed in Jameson et al. (1998). Prediction of the effects of 

pollutants on coral reefs is difficult due to the paucity of toxicological information for corals. 

An endangered or rare ecosystem type might be diminished by physical destruction, 

which is readily observed and quantified, or by physical conversion to another type of ecosystem 

(e.g., due to selective logging or grazing), which can also be readily observed and quantified if 

the type is clearly defined. The prediction of loss of an ecosystem type due to extirpation of 

many or most of the constituent organisms (e.g., due to an herbicide application or oil spill) is 

practical because it would involve severe toxicity. However, loss of a type due to more subtle 

effects, such as changes in species composition due to differential susceptibility to a stressor, 

could be difficult to predict. Information useful in identifying rare and endangered ecosystem 

types is available from NatureServe (http://www.natureserve.org), a nonprofit organization that 

works with natural heritage programs throughout the United States and elsewhere in the Western 

Hemisphere. NatureServe maintains databases on all known ecological communities in the 

United States, ranked from critically imperiled to secure. According to NatureServe, the 

completeness of inventory and classification work varies widely among states, provinces, and 

regions. 

A.3.5. GEAE #11. Function of Assessment Communities, Assemblages, and Ecosystems 

Laws, Regulations, and Precedents: Function 

Although the importance of ecosystem function is widely recognized, precedent for its 

use as an independent endpoint at EPA is limited, except in the case of wetlands. Protection of 

functional attributes of wetlands is specifically targeted, for example, in EPA’s “Guidelines for 

Specification of Disposal Sites for Dredged and Fill Material” (40 CFR, Part 230), implementing 

Section 404(b)(1) of the CWA. Commonly recognized functions of wetlands include storage 

and filtration of water and maintenance of habitat for fish and wildlife. 

Practicality: Function 

Losses of wetland functions can be inferred from loss of wetlands area (see GEAE #10, 

A.3.4), but they are less readily observed or predicted if not accompanied by the loss of wetland 

area. The hydrogeomorphic method (Brinson, 1993) is one approach for assessing wetlands 

function. EPA, the Corps, and other federal agencies have agreed to formally adopt this method 

to improve the assessment of wetlands function in support of the CWA Section 404 Program (62 

48
FR 33607, June 20, 1997). Toxic effects on wetland functions or on the type of wetland 

community are difficult to predict. 

A.3.6. GEAE #12. Physical Structure of Assessment Communities, Assemblages, and 

Ecosystems 

Laws, Regulations, and Precedents: Physical Structure 

Policy support for physical structure of ecosystems as a GEAE stems from the CWA’s 

goals of protecting aquatic ecosystems. The CWA (§101(a)) states that, “The objective of this 

Act is to restore and maintain the chemical, physical [emphasis added], and biological integrity 

of the Nation’s waters.” The importance of physical structure is reflected by EPA regulations 

implementing the CWA that note the following conditions of a water body that may preclude 

attainment of desired beneficial uses (40 CFR §131.10 (g)): 

• “natural, ephemeral, intermittent or low flow conditions of water levels” 

• “dams, diversions or other types of hydrologic modifications” 

• “physical conditions related to the natural features of the water body, such as the lack 

of a proper substrate, cover, flow, depth, pools, riffles, and the like, unrelated to water 

quality” 

Protocol for Developing Sediment TMDLs (U.S. EPA, 1999e) lists channel modification, 

pool filling, filling of substrate with fine sediments, and other effects on physical structure as 

sediment issues that can result in loss of designated uses. These changes in stream ecosystems 

are themselves changes in the ecosystem attributes that result in the lost recreational/aesthetic or 

other uses, not simply stressors that affect biological endpoints. 

Physical structure has been a factor in setting the designated use of streams in state water 

quality standards. For example, in Ohio, a designated use of Modified Warmwater Habitat 

applies to streams with extensive and irretrievable physical habitat modifications. 

Practicality: Physical Structure 

Physical characteristics often are readily observed or measured at sites being assessed 

and are usually recorded in biological surveys. Protocols exist for measuring many aquatic 

habitat attributes (e.g., U.S. EPA, 1999c). In addition, most of the actions that modify the 

physical structure of waterbodies (e.g., channelization, dam construction and operation, water 

withdrawals, and culvert installation) have obvious effects on structure that are readily predicted. 

49
Other effects, such as changes in hydrology resulting from changes in land use, are more 

difficult—but still possible—to model. 

A.4. Officially Designated Endpoints 

The GEAEs in this section do not fall neatly into the organism-population-communityecosystem hierarchy used to organize the other GEAEs, but they are important to EPA 

nonetheless. Habitat for endangered species (GEAEs #13 and #14) is highlighted because of the 

specific protections it receives under the ESA. Habitat has not been chosen as a GEAE for other 

categories of organisms because it is the organisms that are valued directly, whereas by 

definition habitat is that which supports organisms and thus is valued indirectly. (Habitat here is 

distinguished from communities and ecosystems, which may be valued in their own right, as 

discussed in Section A.3.) Ecological properties of special places (GEAE #15) can encompass 

attributes from all levels of biological organization. Special places are identified because of the 

extensive legal and other support for their protection or because of their ecological importance. 

A.4.1. GEAEs #13 and #14. Area and Quality of Habitat for Threatened or Endangered 

Species 

Laws, Regulations, and Precedents: Area and Quality of Critical Habitat 

The obligation to protect endangered and threatened species under the ESA includes 

protection of the critical habitats on which they depend. Thus the legal and regulatory basis for 

protecting endangered species described under GEAE #3 generally also applies to this endpoint. 

For example, the Superfund NCP specifies that, “evaluations shall be performed to assess threats 

to the environment, especially sensitive habitats and critical habitats of species protected under 

the Endangered Species Act” (emphasis added) (U.S. EPA, 1989). EPA’s regulations for State 

and Local Assistance (40 CFR, Part 35, Appendix A to Subpart H) require that project proposals 

determine whether there would be significant adverse effects on critical habitat of endangered 

species. 

Practicality: Area and Quality of Critical Habitat 

Designated critical habitat is readily identified, and it should be practical to determine 

whether it will be destroyed (reduced area) or adversely modified (reduced quality). Although 

critical habitat has not been officially designated for many endangered or threatened species, 

federal documents such as listing decisions and recovery plans typically discuss the distribution 

and ecological requirements of listed species. Toxic effects may be predicted if species or taxa 

that are components of critical habitat are identified and their response to pollutants can be 

evaluated. 

50
A.4.2. GEAE #15. Ecological Properties of Special Places 

Laws, Regulations, and Precedents: Special Places 

The legislative acts establishing national parks and monuments, wildlife refuges, 

wilderness areas, wild and scenic rivers, recreation areas, marine sanctuaries, and other special 

places establish their status and indicate the properties for which the protected status was 

provided. Several statutes either give EPA a role in designating special places or direct EPA to 

consider environmental impacts to such places in administering Agency programs. The CWA 

directs EPA to administer the National Estuary Program and permits states to designate 

waterbodies as Outstanding National Resource Waters, which then receive increased protection 

in their water quality standards. 

The CAA also has several provisions for special places. Section 160 of the CAA 

establishes that a purpose of the act is “to preserve, protect, and enhance the air quality in 

national parks, national wilderness areas, national monuments, national seashores, and other 

areas of special national or regional natural, recreational, scenic, or historic value.” Section 162 

designates national (and international) parks, wilderness areas, and memorial parks of a certain 

size as “class I” areas, which merit the highest level of protection from air pollution. Other 

special places cited in both the CAA and the CWA include the Great Lakes, Chesapeake Bay, 

and Lake Champlain. 

In the area of EPA regulations and guidance, the NCP cites special places such as 

national marine sanctuaries and estuarine research reserves as natural resources to be protected 

under CERCLA. Superfund removal process guidance (U.S. EPA, 1992b) recommends that the 

On-Scene Coordinator to undertake special considerations for actions that include wild and 

scenic rivers. EPA procedures for implementing NEPA (40 CFR §6.108) require an 

environmental impact statement to be prepared if “the proposed action may have significant 

adverse effects on parklands, preserves, or areas of recognized scenic, recreational, 

archeological, or historic value.” “Guidelines for Specification of Disposal Sites for Dredged or 

Fill Material” (40 CFR, Part 230, Subpart E) recommend consideration of potential impacts on 

special aquatic sites, including sanctuaries and refuges. The protocol for screening-level 

ecological risk assessment for hazardous waste combustion facilities calls for special 

consideration of areas having legislatively conferred protection (U.S. EPA, 1999a). 

Practicality: Special Places 

Special places and their important ecological properties usually can be defined readily. 

Given the diverse set of ecological properties at different places, it is not possible to make 

overall statements about the practicality of this endpoint. Potentially, all of the surveying, 

testing, and modeling methods discussed in the previous sections could be applicable. 

51
APPENDIX B. TYPES OF VALUES ASSOCIATED WITH ASSESSMENT ENDPOINTS 

EPA’s ecological risk assessment guidelines (U.S. EPA, 1998a) define an assessment 

endpoint as “an explicit expression of the environmental value that is to be protected, 

operationally defined by an ecological entity and its attributes” [emphasis added]. In the context 

of the guidelines, an environmental value refers to a component of the environment (or an 

ecological entity) that society values, with some examples being endangered species and 

commercially or recreationally important species. The literature on environmental valuation 

covers a wide range of ecological systems and components; for example, bays (Kahn, 1985), 

wetlands (Barbier, 1993), riparian corridors (Lant and Tobin, 1989), deserts (Richer, 1995), 

recreation areas (Adamowicz et al., 1994), and wilderness or “unspoiled” natural areas (Hanink, 

1995; Kopp and Smith, 1993; Randall and Peterson, 1984). In many of these studies, 

ecosystems are conceptualized as having assets or structural components such as energy 

resources, minerals, or timber; services or natural functions benefitting society (e.g., 

groundwater recharge, flood control, the absorption or assimilation of pollutants) and/or other 

attributes provided by the whole ecosystem, such as biological diversity, cultural uniqueness, or 

natural heritage (Westman, 1977; Daily et al., 1997). 

Table B-1 presents one way of organizing environmental values, drawing on Blomquist 

and Whitehead (1995), Daily (2000), Ehrlich and Ehrlich (1981), MacLean (1995), Primack 

(1993), and Freeman (1984, 1993). The table is not intended to represent a definitive or 

comprehensive list of environmental values, rather it is intended to illustrate the breadth of 

values that may be cited in support of a GEAE. 

Each of the GEAEs presented in this document relate to one or more of these 

environmental values. For example, an “assessment population” and its attributes may be used 

to represent a commercially and recreationally valuable fish or wildlife population (consumptive 

and recreational values). Such an assessment population could also represent a species 

population that is valued as a learning tool (educational value) and protected for cultural and 

aesthetic reasons (preservation value). Table B-1 provides further examples of how each of the 

GEAEs may correspond with these values. 

52
Table B-1. Some categories of environmental values 

Value Definition and examples of corresponding GEAEs 

Consumptive The value of commodities produced by the environment such as food, energy, timber, 

fiber, and pharmaceutical and industrial products. 

• Area of ecosystems: timber and fuel production by trees 

• Production of an assessment population: commercially valuable fisheries 

• Extirpation of an assessment population: commercially valuable furbearers 

Informational The value of natural structures, chemicals, or processes as models for anthropogenic 

structures, chemicals, or processes (e.g., pharmaceuticals, synthetic commodities, 

engineering designs). Also see Option value. 

• Extirpation of organisms: as sources of model adaptations to extreme 

environments 

• Taxa richness of communities: highly diverse communities may be valuable 

sources of bioactive chemicals as models for pharmaceuticals 

Functional The value of ecological functions benefitting public health and welfare, such as 

pollen and seed dispersal, water retention and purification, detoxification of wastes, 

and moderation of weather extremes. In some cases, ecosystems are re-established to 

make use of their functional value for remediation. 

• Ecosystem function: water retention and purification by wetlands 

• Abundance of an assessment community: water and soil retention by forests 

• Abundance of an assessment population: pollination by insects 

Recreational The value of recreational opportunities such as fishing, birding, boating, and hiking. 

In some cases, this is a passive use of a resource, but in others (e.g., tourism) it is an 

economic activity. 

• Physical structure of an ecosystem: boating, fishing 

• Survival, fecundity, and growth of organisms (migratory birds): birding, 

hunting 

• Properties of special places: camping, hiking, boating 

Educational The value of academic and nonacademic educational opportunities, including nature 

and scientific study. 

• Properties of special places: parks and refuges for nature study, research 

• Area of ecosystems: environmental education sites 

Option The value to future generations of preserving the option of using the environment at 

some future time. Option value also includes human welfare gains or net benefits 

associated with delaying a decision when there is uncertainty about the payoffs of 

certain alternatives, or when one of the choices involves an irreversible commitment 

of resources. 

• Area and function of ecosystems 

• Properties of special places 

• Abundance of assessment populations 

Existence Value ascribed to the existence of ecological systems independent of any direct 

services or functions. Aesthetic, moral, cultural, religious, or spiritual grounds may 

be cited in support of this type of nonuse value. 

• Area and quality of critical habitat for endangered species 

• Gross anomalies and kills of organisms 

• Properties of special places 

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59
Appendix 11 – Environmental Risk Screen
Table 1 – PB-HAP Benchmarks Included in the Environmental Risk Screen

EcoHAP Assessment Endpoint Benchmark Effects Level Benchmark Value

Benchmark 

Source

Tier 1 Eco 

Screening 

Threshold 

(TPY)

Cadmium Fish - Avian Piscivores NOAEL (merganser) 0.7 (mg/kg BW/day) d 2.03E-01

Cadmium Fish - Avian Piscivores LOAEL (merganser) 1 (mg/kg BW/day) d 2.90E-01

Cadmium Fish - Mammalian Piscivores NOAEL (mink) 0.742 (mg/kg BW/day) e 4.06E-01

Cadmium Fish - Mammalian Piscivores LOAEL (mink) 7.42 (mg/kg BW/day) e 4.06E+00

Cadmium Sediment Community No-effect Level 0.6 (mg/kg dry wt) b 1.73E+00

Cadmium Sediment Community Threshold Level 1.2 (mg/kg dry wt) a 3.45E+00

Cadmium Sediment Community Probable-effect Level 3.5 (mg/kg dry wt) b 1.01E+01

Cadmium Surface Soil - Dist. 1 - 312 m Threshold - Mammalian Insectivores (shrew) 0.36 (mg/kg dry wt) a 3.64E-01

Cadmium Surface Soil - Dist. 1 - 312 m Threshold - Avian Ground Insectivores (woodcock) 0.77 (mg/kg dry wt) a 7.79E-01

Cadmium Surface Soil - Dist. 1 - 312 m Threshold Level - Plant Community 32 (mg/kg dry wt) a 3.24E+01

Cadmium Surface Soil - Dist. 1 - 312 m Threshold Level - Invertebrate Community 140 (mg/kg dry wt) a 1.42E+02

Cadmium Surface Soil - Dist. 2 - 850 m Threshold - Mammalian Insectivores (shrew) 0.36 (mg/kg dry wt) a 5.21E-01

Cadmium Surface Soil - Dist. 2 - 850 m Threshold - Avian Ground Insectivores (woodcock) 0.77 (mg/kg dry wt) a 1.11E+00

Cadmium Surface Soil - Dist. 2 - 850 m Threshold Level - Plant Community 32 (mg/kg dry wt) a 4.63E+01

Cadmium Surface Soil - Dist. 2 - 850 m Threshold Level - Invertebrate Community 140 (mg/kg dry wt) a 2.03E+02

Cadmium Surface Soil - Dist. 3 - 1,500 m Threshold - Mammalian Insectivores (shrew) 0.36 (mg/kg dry wt) a 7.53E-01

Cadmium Surface Soil - Dist. 3 - 1,500 m Threshold - Avian Ground Insectivores (woodcock) 0.77 (mg/kg dry wt) a 1.61E+00

Cadmium Surface Soil - Dist. 3 - 1,500 m Threshold Level - Plant Community 32 (mg/kg dry wt) a 6.69E+01

Cadmium Surface Soil - Dist. 3 - 1,500 m Threshold Level - Invertebrate Community 140 (mg/kg dry wt) a 2.93E+02

Cadmium Surface Soil - Dist. 4 - 3,500 m Threshold - Mammalian Insectivores (shrew) 0.36 (mg/kg dry wt) a 1.05E+00

Cadmium Surface Soil - Dist. 4 - 3,500 m Threshold - Avian Ground Insectivores (woodcock) 0.77 (mg/kg dry wt) a 2.24E+00

Cadmium Surface Soil - Dist. 4 - 3,500 m Threshold Level - Plant Community 32 (mg/kg dry wt) a 9.32E+01

Cadmium Surface Soil - Dist. 4 - 3,500 m Threshold Level - Invertebrate Community 140 (mg/kg dry wt) a 4.08E+02

Cadmium Surface Soil - Dist. 5 - 7,500 m Threshold - Mammalian Insectivores (shrew) 0.36 (mg/kg dry wt) a 2.99E+00

Cadmium Surface Soil - Dist. 5 - 7,500 m Threshold - Avian Ground Insectivores (woodcock) 0.77 (mg/kg dry wt) a 6.40E+00

Cadmium Surface Soil - Dist. 5 - 7,500 m Threshold Level - Plant Community 32 (mg/kg dry wt) a 2.66E+02

Cadmium Surface Soil - Dist. 5 - 7,500 m Threshold Level - Invertebrate Community 140 (mg/kg dry wt) a 1.16E+03

Cadmium Water-column Community Threshold Level 0.25 (ug/L) c 7.66E-01

Cadmium Water-column Community Frank-effect Level 2 (ug/L) c 6.12E+00
Table 1 – PB-HAP Benchmarks Included in the Environmental Risk Screen

Dioxin Fish - Avian Piscivores NOAEL (merganser) 0.0000014 (mg/kg BW/day) f 3.17E-05

Dioxin Fish - Avian Piscivores LOAEL (merganser) 0.000014 (mg/kg BW/day) f 3.17E-04

Dioxin Fish - Mammalian Piscivores NOAEL (mink) 0.000000771 (mg/kg BW/day) f 4.12E-05

Dioxin Fish - Mammalian Piscivores LOAEL (mink) 0.00000771 (mg/kg BW/day) f 4.12E-04

Dioxin Sediment Community Threshold Level 0.00000116 (mg/kg dry wt) g 3.10E-05

Dioxin Surface Soil - Dist. 1 - 312 m Threshold - Mammalian Insectivores (shrew) 0.0000002 (mg/kg dry wt) h 6.69E-07

Dioxin Surface Soil - Dist. 2 - 850 m Threshold - Mammalian Insectivores (shrew) 0.0000002 (mg/kg dry wt) h 9.48E-07

Dioxin Surface Soil - Dist. 3 - 1,500 m Threshold - Mammalian Insectivores (shrew) 0.0000002 (mg/kg dry wt) h 1.28E-06

Dioxin Surface Soil - Dist. 4 - 3,500 m Threshold - Mammalian Insectivores (shrew) 0.0000002 (mg/kg dry wt) h 2.08E-06

Dioxin Surface Soil - Dist. 5 - 7,500 m Threshold - Mammalian Insectivores (shrew) 0.0000002 (mg/kg dry wt) h 4.39E-06

Dioxin Water-column Community Threshold Level 0.000012 (ug/L) i 3.84E-03

Dioxin Water-column Community Frank-effect Level 0.1 (ug/L) i 3.20E+01

Mercuric Chloride Sediment Community Threshold Level 0.15 (mg/kg dry wt) a 9.11E-03

Mercuric Chloride Sediment Community Probable-effect Level 0.7 (mg/kg dry wt) j 4.25E-02

Mercuric Chloride Surface Soil - Dist. 1 - 312 m Threshold Level - Plant Community 0.3 (mg/kg dry wt) k 9.25E-03

Mercuric Chloride Surface Soil - Dist. 1 - 312 m Threshold Level - Invertebrate Community 0.1 (mg/kg dry wt) k 3.08E-03

Mercuric Chloride Surface Soil - Dist. 2 - 850 m Threshold Level - Plant Community 0.3 (mg/kg dry wt) k 1.35E-02

Mercuric Chloride Surface Soil - Dist. 2 - 850 m Threshold Level - Invertebrate Community 0.1 (mg/kg dry wt) k 4.50E-03

Mercuric Chloride Surface Soil - Dist. 3 - 1,500 m Threshold Level - Plant Community 0.3 (mg/kg dry wt) k 1.78E-02

Mercuric Chloride Surface Soil - Dist. 3 - 1,500 m Threshold Level - Invertebrate Community 0.1 (mg/kg dry wt) k 5.93E-03

Mercuric Chloride Surface Soil - Dist. 4 - 3,500 m Threshold Level - Plant Community 0.3 (mg/kg dry wt) k 2.70E-02

Mercuric Chloride Surface Soil - Dist. 4 - 3,500 m Threshold Level - Invertebrate Community 0.1 (mg/kg dry wt) k 8.99E-03

Mercuric Chloride Surface Soil - Dist. 5 - 7,500 m Threshold Level - Plant Community 0.3 (mg/kg dry wt) k 7.23E-02

Mercuric Chloride Surface Soil - Dist. 5 - 7,500 m Threshold Level - Invertebrate Community 0.1 (mg/kg dry wt) k 2.41E-02

Mercuric Chloride Water-column Community Threshold Level 0.77 (ug/L) c 7.78E-01

Mercuric Chloride Water-column Community Frank-effect Level 1.4 (ug/L) c 1.42E+00

Mercury (methyl) Fish - Avian Piscivores NOAEL (merganser) 0.013 (mg/kg BW/day) f 7.55E-03

Mercury (methyl) Fish - Avian Piscivores LOAEL (merganser) 0.078 (mg/kg BW/day) f 4.53E-02

Mercury (methyl) Fish - Mammalian Piscivores NOAEL (mink) 0.0247 (mg/kg BW/day) e 4.01E-02

Mercury (methyl) Fish - Mammalian Piscivores LOAEL (mink) 0.123 (mg/kg BW/day) e 2.00E-01

Mercury (methyl) Sediment Community Threshold Level 0.2 (mg/kg dry wt) l 5.43E+00

Mercury (methyl) Sediment Community Probable-effect Level 1 (mg/kg dry wt) l 2.72E+01

Mercury (methyl) Surface Soil - Dist. 1 - 312 m Threshold Level - Invertebrate Community 0.67 (mg/kg dry wt) I 1.25E+00
Table 1 – PB-HAP Benchmarks Included in the Environmental Risk Screen

References:

a. U.S. EPA OSWER

b. Environment Canada

c. U.S. EPA OW

d. CA DTSC HERD (2009)

e. Sample, et. al, 1996

f. U.S. EPA 1995

g. U.S. EPA Region 3, 4, and 5.

h. U.S. EPA Region

i. U.S. EPA Region 4

j. Florida DEP, NOAA

k. ORNL and EPA R4, R6

l. MacDonald, et. al. 2000

m. U.S. EPA Region 6

n. NAAQS for Lead, Secondary 

Standard

Mercury (methyl) Surface Soil - Dist. 2 - 850 m Threshold Level - Invertebrate Community 0.67 (mg/kg dry wt) i 1.82E+00

Mercury (methyl) Surface Soil - Dist. 3 - 1,500 m Threshold Level - Invertebrate Community 0.67 (mg/kg dry wt) i 2.40E+00

Mercury (methyl) Surface Soil - Dist. 4 - 3,500 m Threshold Level - Invertebrate Community 0.67 (mg/kg dry wt) i 3.62E+00

Mercury (methyl) Surface Soil - Dist. 5 - 7,500 m Threshold Level - Invertebrate Community 0.67 (mg/kg dry wt) i 9.71E+00

Mercury (methyl) Water-column Community Threshold Level 0.0028 (ug/L) c 3.30E-01

Mercury (methyl) Water-column Community Frank-effect Level 0.099 (ug/L) c 1.17E+01

PAH Fish - Mammalian Piscivores NOAEL (mink) 0.417 (mg/kg BW/day) e 4.72E+02

PAH Fish - Mammalian Piscivores LOAEL (mink) 4.17 (mg/kg BW/day) e 4.72E+03

PAH Sediment Community No-effect Level 0.032 (mg/kg dry wt) b 4.73E+00

PAH Sediment Community Threshold Level 0.15 (mg/kg dry wt) l, h 2.22E+01

PAH Sediment Community Probable-effect Level 1.45 (mg/kg dry wt) l 2.14E+02

PAH Surface Soil - Dist. 1 - 312 m Threshold - Mammalian Insectivores (shrew) 1.52 (mg/kg dry wt) h 3.45E+00

PAH Surface Soil - Dist. 2 - 850 m Threshold - Mammalian Insectivores (shrew) 1.52 (mg/kg dry wt) h 5.09E+00

PAH Surface Soil - Dist. 3 - 1,500 m Threshold - Mammalian Insectivores (shrew) 1.52 (mg/kg dry wt) h 8.22E+00

PAH Surface Soil - Dist. 4 - 3,500 m Threshold - Mammalian Insectivores (shrew) 1.52 (mg/kg dry wt) h 2.02E+01

PAH Surface Soil - Dist. 5 - 7,500 m Threshold - Mammalian Insectivores (shrew) 1.52 (mg/kg dry wt) h 5.06E+01

PAH Water-column Community Threshold Level 0.014 (ug/L) a, h, m 1.84E+01

PAH Water-column Community Frank-effect Level 0.24 (ug/L) a 3.16E+02

Lead Ambient Air NAAQS Secondary Standard 0.15 ug/m3 n NA
Table 2 – Acid Gas Benchmarks Included in the Environmental Risk Screen

a- Note that the human health RfC is 20 μg/m3, which is lower than the ecological benchmark.

Acid Gas Chronic 90-day Benchmark in μg/m3

Hydrochloric acid - LOEL 50a

Hydrofluoric acid – Plant Community LOEL 0.5

Hydrofluoric acid – Plant Community LOEL 0.4