EPA/630/R-94/008

November 1994

PEER REVIEW WORKSHOP REPORT ON

ECOLOGICAL RISK ASSESSMENT

ISSUE PAPERS

Risk Assessment Forum

U.S. Environmental Protection Agency

Washington, DC 20460

@ Printed on RecycledPaper
DISCLAIMER

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

Agency policy and approved for publication. Mention of trade names or commercial

products does not constitute endorsement or recommendation for use.

ii
CONTENTS

Figures . . . . . . . . . .'. . . ',' . .'. .' . . . . . . . . . . .. . . . . . . . . '.' . . . . . . . .. v

Acknowledgements ..........,................ . . . . . . . . . . . . . . . . .. vi

Foreword Vll

1. INTRODUCTION 1

1.1. Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3

1.2. The Peer Review Process 5

1.3. Overall Highlights of the Workshop 5

2. KEYNOTE PRESENTATIONS 7

2.1. Welcome and Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7

2.2. Workshop Objectives and Structure 9

3. RECOMMENDATIONS FOR REVISION OF ISSUE PAPERS. . . . . . . . . . . .. 11

3.1. Overview 11

3.2. Ecological Significance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12

3.3. Conceptual Model Development 12

3.4. Characterization of Exposure 13

3.5. Effects Characterization 13

3.6. Biological Stressors 14

3.7. Ecological Recovery 14

3.8. Uncertainty in Ecological Risk Assessment . . . . . . . . . . . . . . . . . . . . .. 15

3.9. Risk Integration Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 15

4. IDENTIFICATION OF CROSS-CUITING ISSUES . . . . . . . . . . . . . . . . . . .. 17

5. RECOMMENDATIONS FOR DEVELOPING ECOLOGICAL RISK

ASSESSMENT GUIDELINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 19

5.1. Background and Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 19

5.2. Recommendations on Guidelines From Summary of Group 1 . . . . . . . . . .. 20

5.2.1. Modell Outline 21

5.2.2. Additional Recommendations 22

5.2.3. Best Assessment Practices 24

5.2.4. Goals and Uses of Ecological Risk Assessment. . . . . . . . . . . . . .. 25

iii
CONTENTS (Continued)

5.3. Recommendations on Guidelines From Group 2 (Ecological Significance,

Uncertainty, Risk Integration Groups) . . . . . . . . . . . . . . . . . . . . . . . .. 26

5.4. Conceptual Model Development 27

5.5. Characterization of Exposure 27

5.6. Effects Characterization 28

5.7. Biological Stressors .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 29

5.8. Ecological Recovery 30

5.9. Uncertainty in Ecological Risk Assessment . . . . . . . . . . . . . . . . . . . . .. 30

6. FUTURE RESEARCH AND DEVELOPMENT NEEDS . . . . . . . . . . . . . . . .. 33

6.1. Overview 33

6.2. Ecological Significance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 33

6.3. Conceptual Model Development 34

6.4. Characterization of Exposure 34

6.5. Effects Characterization 34

6.6. Biological Stressors . . . . . . . . . . . . . . . . . . . . . . . . .. 35

6.7. Ecological Recovery 36

6.8. Uncertainty in Ecological Risk Assessment . . . . . . . . . . . . . . . . . . . . .. 36

6.9. Risk Integration Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 36

7. REFERENCES 39

APPENDIX A - Reviewers A-I

APPENDIX B - Authors B-1

APPENDIX C - Observers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-l

APPENDIX D - Agenda D-l

APPENDIX E - Pre-Meeting Comments E-l

APPENDIX F - Detailed Recommendations for Revision of Issue Papers . . . . . . . . . F-l

iv
Figure 1.

Figure 2.

Figure 3.

Figure 4.

FIGURES

The Conceptual Framework for Ecological Risk Assessment 4

Development of Ecological Risk Assessment Guidelines . . . .. . . . . . .. 8

The "Cube" - A Three-Dimensional Matrix of Ecological Risk

Organizing Principles 23

The Process Flow Diagram Developed by the Conceptual Model

Development Work Group F-7

v
ACKNOWLEDGEMENTS

This repOlt represents the efforts of numerous individuals who served as issue paper

reviewers, authors, and in other capacities at the Ecological Risk Assessment Issue Paper

Peer Review 'Vorkshop. Special recognition goes to Richard A. Kimerle, workshop Chair,

for directing this productive meeting. The following eight Work Group Leaders also made

significant contributions to the workshop report: William J. Adams, John Bascietto, Gregory

R. Biddinger, James A. Drake, Jeffrey M. Giddings, James R. Karr, A. Frederick Holland,

and Kent W. Thornton. William H. van der Schalie and John H. Gentile, the Risk

Assessment Forum coordinators for ecological effects, coordinated all workshop and issue

paper development activities. David P. Bottimore of Versar, Inc., an E,PA contractor,

worked on all phases of the project, providing technical, administrative, "and logistical

support. Other Versar personnel making significant contributions to the workshop included

Stephen W. Duda, Margaret J. Wilson, and Patricia H. Wood.

VI
FOREWORD

On August 16-18, 1994, the U.S. Environmental Protection Agency's (EPA's) Risk

Assessment Forum convened a 3-day workshop in Alexandria, Virginia, to peer review eight

ecological risk assessment issue papers. Development of these issue papers was part ofa

long-term effort to develop Agencywide ecological risk assessment guidelines for EPA.

Preliminary work on guideline development began in 1989 and included a series of colloquia

sponsored by EPA's Risk Assessment Forum to identify and discuss significant issues in

ecological risk assessment (U.S. EPA, 1991). Based on this early work and on consultations

with EPA's Science Advisory Board, EPA decided to develop ecological risk guidance in

stepwise fashion, starting with definitions of terms and concepts and continuing with the

development of source materials for the guidelines. The first product of this effort was the

report Framework for Ecological Risk Assessment (U.S. EPA, 1992a,b), which proposes

basic principles and terminology for the ecological risk assessment process. Since that time,

other materials have been developed, including suggestions for guideline structure (U.S.

EPA, 1992c), ecological risk assessment case studies (U.S. EPA, 1993a; U.S. EPA, 1994),

and the draft issue papers peer reviewed at this workshop (U.S. EPA, 1993b).

The issue papers were developed to help provide scientific and technical information that

EPA scientists could use along with other materials to develop ecological risk assessment

guidance. EPA did not ask the issue paper authors to provide guidance, to write a

"cookbook" or "how to" of methods, or to resolve differences between the papers in

terminology or approach. Rather, EPA asked for a document of limited scope that would

highlight important principles and approaches relevant to the ecological risk assessment

framework that EPA scientists should consider in preparing guidelines. Synthesis and

integration of the issue papers, framework principles, case studies, and other materials are

deliberately reserved for the guideline writers and subsequent peer reviewers and public

commenters.

This report summarizes discussions at the workshop, which was chaired by Dr. Richard

A. Kimerle of Monsanto Company. Ineluded in the report are recommendations for revising

the draft issue papers, an identification of cross-cutting issues and future research needs, and

suggestions on possible structures for EPA's ecological risk assessment guidelines. These

suggestions will be very useful to EPA as it begins the challenging task of developing

ecological risk assessment guidelines.

William P. Wood, Ph.D.

Executive Director

Risk Assessment Forum

vii

1. INTRODUCTION

The Ecological Risk Assessment Issue Paper Peer Review Workshop was held on

August 16-18, 1994, at the Radisson Mark Plaza Hotel in Alexandria, Virginia. The purpose

of the workshop was to provide the u.s. Environmental Protection Agency with:

• Recommendations on revisions to

the eight issu~ papers on

ecological risk assessment (see

text box for a list of the issue

papers);

• Identification of "cross-cutting

issues" in the eight issue papers;

• Suggestions for development of

ecological risk assessment

guidelines; and

::;:::;:;::::, :;.::;:;.:..;. :.. . :':::::::':':::':'::;':':::::'~"':':':':':':':';':':"':-:':';':';';"';"';';'.. .... . ..

• llecommendations on future

research and development needs to

improve the science of ecological

risk assessment.

Twenty-five scientists from academi~, industry, and State and Federal agencies

participated as peer reviewers (appendix A). Also attending the workshop were the authors

of the issue papers (appendix B) and observers (appendix C). The workshop began with

plenary sessions to review the history behind the development of the issue papers, to provide

the charge to the reviewers, and to discuss the agenda for the meeting (appendix D).

Breakout sessions, organized according to the eight issue papers, facilitated teamwork

between the reviewers and the authors. Following these working sessions to formulate the

revisions to the issue papers, participants focused on identifying the cross-cutting issues,

discussing potential structures for the ecological risk assessment guidelines, and identifying

fpture research and development needs to improve the science of ecological risk assessment.

1
The major outputs and recommendations from the workshop are summarized below.

• All eight issue papers are suitable for publication upon revision based on the

comments provided. All eight papers (and one additional paper, "Public Values

Affecting Ecological Significancelf

) will be published together in one EPA document

in fall 1994.

• An introductory chapter to the issue paper document will be added by the Risk

Assessment Forum that summarizes the objectives, scope, limitations, and intended

use of the issue papers.

• Several cross-cutting issues were identified in some of the eight issue papers. It was

decided that some of these cross-cutting issues would not ,be addressed in the issue

papers and should be considered by EPA in the development of ecological risk

assessment guidelines. Some of these cross-cutting issues include:

Tc~rminology-A dictionary or glossary is needed; definitions of multiple uses of

the terms also should be included.

Examples/Case Studies-The issue papers are not intended to be "how to"

manuals, but should have examples to help illustrate concepts. Therefore, the

guidelines will need to include illustrative examples to demonstrate concepts.

Data Quality Assurance and Adequacy-The data quality objective (DQO),

process can help risk assessors determine the level of confidence needed by risk

managers to make a decision.

• Ecological risk assessment guidelines should build on the EPA report Framework for

Ecological Risk Assessment (Framework Report, U.S. EPA, 1992a), with

components that are common to any endpoint, application, media, or data source.

Some conceptual diagrams from the Framework Report should be revised to reflect

the current thinking that ecological risk assessment is an iterative process.

Section 2 of this document contains summaries of the keynote presentations on the

objectives of the workshop by Dorothy E. Patton, Chair and Executive Director of EPA's

Risk Assessment Forum (RAF), and Richard A. Kimerle, Chair of the workshop. Provided

in section 3 are summaries of recommendations given to the authors for revisions to the issue

papers. Section 4 describes the cross-cutting issues identified by the reviewers for

consideration in revising the issue papers and in formulating guidelines on ecological risk

assessment. Sections 5 and 6 present suggestions to EPA on formulating ecological risk

assessment guidelines and on future research needs, respectiv~ly.

2
1.1. Background

In 1989, the RAF initiated a multiyear program for developing Agencywide guidance for

ecological risk assessment. Ecological risk assessment is defined as a process that evaluates

the likelihood that adverse ecological effects may occur or are occurring as a result of

exposure to one or more stressors. Drawing on experience from EPA's human health risk

assessment guidelines, the RAF developed a range of materials to be used by Agency

scientists in developing ecological risk assessment guidelines. A first major result of this

process was the 1992 publication of the Framework Report, which proposed a simple,

flexible structure, or framework, for ecological risk assessment. The framework developed

for ecological risk assessment is illustrated in figure 1. Following publication of the

Framework Report, EPA sought to bridge the gap between the simple structure of the

framework and the future guidelines through development of case studies and issue papers.

EPA solicited advice and expertise of the academic community, industry, and other scientists

in applying these concepts to a series of ecological assessment case studies (U.S. EPA,

1993a; U.S. EPA, 1994). In 1993, EPA asked nationally recognized experts to prepare a

series of eight issue papers identifying scientific issues for the phases of the· ecological risk

assessment process as defined in the Framework Report. The eight issue papers include:

• Ecological Significance

• Conceptual Model Development

• Characterization of Exposure

• Effects Characterization

• Biological Stressors

• Ecological Recovery

• Uncertainty in Ecological Risk Assessment

• Risk Integration Methods

The draft issue papers were made public in 1994 (for purposes of peer review) as one

document (U.S. EPA, 1993b). The authors of the draft issue papers will revise their papers

3
Ecological Risk Assessment

Discussiol1l

Between The

Risk Assessor

and

Risk ManagE~r

(Planning)

Ar--_..L-....l-_---.,--_..L-....l-_---.

n

a Characterization

I of

Exposure

i

s

Figure 1. The Conceptual Framework for Ecological Risk Assessment (adapted from

EPA, 1992a)

4
based on comments received at this peer review workshop. Revised issue papers will be

published together as an EPA report and will be used as source materials to assist Agency

scientists in preparing Agencywide ecological risk assessment guidelines.

1.2. The Peer Review Process

A panel of25 experts in the field of ecological risk assessment was assembled by Versar,

Inc., from academia, private industry, State government, and other Federal agencies to

review the eight issue papers. Panel members were selected from more than 80 potential

candidates identified and contacted through a process that included the use of professional

societies, a literature review, and existing databases. The peer review panel (three reviewers

per issue paper and a workshop Chair) was assembled for a 3-day workshop to provide the

authors with comments on the content of specific papers as well as to identify cross-cutting

issues common to a number of the eight papers.

Prior to the workshop, the reviewers were provided with the draft issue papers, the

Framework Report, other background information, and a list of suggested review topics.

The reviewers were asked to submit written comments on the issue papers before the

workshop so that all of the comments could be compiled and provided to other reviewers and

the authors before the meeting. Although initial discussions at the workshop were based on

the pre-meeting comments (appendix E), the dialogue between the reviewers and authors

expanded considerably because of the collaborative nature of the discussions that developed

at the workshop. The recommendations provided by the reviewers on the issue papers ~e

summarized in section 3, while appendix F contains the detailed comments.

1.3. Overall Highlights of the Workshop

This workshop was very successful from a number of perspectives. First and foremost,

the scientific completeness and potential usefulness of the issue papers for the development of

ecological risk assessment guidelines were enhanced by the format of the workshop. The

5
strategies of providing written peer reviews before the workshop, having face-to-face

discussions between authors and reviewers in the plenary and breakout sessions, and

providing opportunities for dialogue between all workshop participants contributed to the

success. In addition, presentations by the RAF staff describing the history of the guideline

development process and the intended use of the issue papers helped to focus the peer

review. Also contributing to the workshop's success was the genuine commitment on the

part of all the participants and observers to make the issue papers as successful as possible,

as a step toward ensuring success in the ultimate goal of guideline development.

Additionally, this workshop was somewhat unusual because· of the wide:diversity of

valuable ecologiC'.al expertise and experience represented, the willingness of participants to

share their viewpoints, and the respect shown for the diverse viewpoints as participants

listened and incorporated the many varied ideas into the materials·. Numerous individuals

commented on how their perspectives for assessing ecological risk were broadened as aresult

of the conversations with their scientific peers.

After the issue paper reviews were completed, an opportunity was provided for

participants to contribute ideas on the Agency's use of the framework, case studies, and issue

papers to develop ecological risk assessment guidelines. Once again, the diverse expertise

and varied viewpoints of the participants from academia, industry, public interest groups, and

State and Federal government agencies provided valuable input. The group was keenly

interested in assuring thatthe subsequent effort to develop the ecological risk assessment

guidelines would be performed in the most scientifically defensible manner possible..

6
2. KEYNOTE PRESENTATIONS

2.1. Welcome and Introduction

The meeting was opened by Dorothy E. Patton, Chair and Executive Director of the

RAF, who provided an overview of the history of EPA's ecological risk assessment guideline

development process. The Framework Report was the original document that established a .

flexible structure for assessing ecological risks. The framework defined a three-phase

process composed of problem formulation, analysis, and dsk characterization. This

Framework Report was followed by the development of case studies and issue papers. The

issue papers identified the scientific issues associated with the risk assessment process, while

the case studies provided specific examples of the complexity of the ecological risk

assessment process for a range of ecosystem types and scenarios. The case studies also

represent an array of topics including data completeness, data quality, and types of

assessments (e.g., qualitative vs. quantitative). EPA's overall process for development of

ecological risk assessment guidelines is presented in figure 2.

The primary audience for the issue papers is EPA's guideline writers, while secondary

audiences include EPA's Program Offices and others who conduct ecological risk

assessments. The issue papers are not treatises or monographs, nor are they "how to"

documents; rather, they review the current state of knowledge of issues associated with

ecological risk assessment. They are designed to be used by the guideline writers as source

materials along with the Framework Report, case studies, and scientific literature. Synthesis

and integration of these materials will take place during the guideline development process

through peer review and consensus-building with experts throughout EPA, academia,

industry, environmental groups, consulting firms, State governments, and other Federal

agencies.

7
1990-1992

/ /

1992-1994 1!994-1996

Figure 2. Dev1elopment of Ecological Risk Assessment Guidelines

8
2.2•.. 'Vorkshop Objectives and Structure

Richard A. Kimerle of Monsanto Company, the workshop Chair, provided an overview

of the need for "useful products" that can be used in ecological risk assessment. He stressed

that although the topic is complex, a simplified approach is needed for risk assessors

throughout Federal and State governments, industry, environmental groups, and the

interested public. The Chair also presented the following workshop objectives and the

charge to the reviewers:

• Provide recommendations to the issue paper authors so that the authors can finalize

the issue papers, and, in the process, try to maintain a reasonable consistency

between the Framework Report and the issue papers;

• Develop recommendations on the potential direction and structure of the ecological

risk assessment guidelines; and

• Identify future needs and research areas, particularly for EPA's Office of Research

and Development, that can fill data gaps and improve the science of ecological risk

assessment.

In addition, several other objectives were detailed induding:

• Identify and discuss cross-cutting issues (topics common to some or all of the eight

individual issue papers); and

• Identify terminology needs and issues.

Because of the ambitious agenda and number of topics to be addressed, the Chair instructed

the reviewers to focus on the immediate need to finalize the issue papers.

9

3. RECOMMENDATIONS FOR REVISION OF ISSUE PAPERS

3.1. Overview

The first day and one-half of the workshop was dedicated to developing detailed critiques

of the eight issue papers and defining the revisions required to finalize the documents.

Following the keynote presentations to set the tone for the workshop, the three reviewers for

each paper and the issue paper authors met in breakout sessions to review the pre-meeting

comments and to discuss revisions to the papers. This collaborative format for peer review

was somewhat unusual. Scientists routinely use anonymous peer review to ensure the quality

of publications for professional journals. However, for this workshop, the peer reviews were

not anonymous and the authors and reviewers met face-to-face to discuss the pre-meeting

comments and to define the revisions to the issue papers. If there were any pre-workshop

concerns over this review process, they were quickly dispelled by the very professional

atmosphere of cooperation. In fact, this format facilitated a spirit of collaboration between

authors and reviewers.

In general, many initial concerns about the scope and content of individual issue papers

were resolved by the recommendation that an introductory overview section be written for

the issue paper document. This section, to be written by the RAF, will provide the context

necessary for readers to understand the purpose, scope, limitations, and intended use of the

issue papers. Issue paper-specific comments generally called for some reorganizing of

sections within individual papers, clearer use of terminology, and incorporation of examples.

Following revisions, nine issue papers (the eight original papers and one additional paper on

"Public Values Affecting Ecological Significance") will be published as an EPA document.

Summaries of recommendations for revision of the eight issue papers that were

developed during breakout work group sessions are presented below. The names of the

authors and reviewers for each issue paper are included following the titles. Sections 3.2

11
through 3.9 present summary lists of recommendations from each group, while appendix F

contains the detailed recommendations for revisions to the papers.

3.2. Ecological Significance

Authors: M. Harwell, B. Norton, W. Cooper, J. Gentile

Reviewers: K. Thornton, R. Bachman, T. O'Connor

Six recommendations were made to the authors of the Ecological Significance paper as

follows:

1. Define f',.cological significance;

2. Reorganize the issue paper;

3. Incorporate the Public Values appendix into a separate issue paper entitled "Public

Values Affecting Ecological Significance";

4. Expand discussions of attributes and criteria;

5. Incorporate additional examples; and

6. Incorporate specific pre-meeting comments, where appropriate.

3.3. Conceptual Model Development

Authors: L. Barnthouse, J. Brown

Reviewers: G. Biddinger, R. Kendall, R. O'Neill

Ten recommendations were made to the authors of the Conceptual Model Development

paper as follows:

1. Provide basic information for a broader audience on the scientific method and the

use of science to make management decisions;

2. Clearly state how conceptual model development focuses the study;

3. Include references identified by reviewers;

4. Include a third case study on a waste site;

5. Reduce the level of detail on characterization of stress;

6. Add statements of scope and purpose;

7. Discuss the importance of documentation and transparency;.

12
8. Consider including a dictionary as an alternative to a glossary;

9. Include a process flow diagram; and

10. Ensure consistency with other issue papers.

3.4. Characterization of Exposure

Authors: G. Suter II, J. Gillett, S. Norton

Reviewers: W. Adams, L. Kapustka, F. Wagner

Five recommendations were made to the authors of the Characterization of Exposure

paper as follows:

1. Follow the exposure characterization descriptions in the Framework Report;

2. Modify some terminology;

3. Revise the figures;

4. Restructure the issue paper; and

5. Provide recommendations on performing exposure characterization for chemical and

nonchemical agents.

3.5. Effects Characterization

Authors: P. Sheehan, O. Loucks

Reviewers: J. Giddings, N. Beyer, W. Landis

Five recommendations were made to the authors of the Effects Characterization paper as

follows:

1. Retain the emphasis in the introductory section on important general concepts;

2. Clearly state that risk assessments should not be based on simplistic "indices";

3. Include additional types of effects in the sections on individual- and population-level

effects;

4. State that many ecosystem structure/function endpoints need more research and

development before they can be routinely used in risk assessment; and

5. Discuss additional research and development needs.

13
In other resPf""cts, the reviewers stated that the paper is comprehensive and adequate

without major revision; however, some minor editing is needed to increase clarity and to

bring out the organization of topics.

3.6. Biological Stressors

Authors: D. Simberloff, M. Alexander

Reviewers: J. Drake, R. Orr, J. Thorp III

The reviewers stated that only a few changes were recommended to the authors because

this is a well-written document. The changes include:

1. Clarify the community/ecosystem concepts; and

2. Include additional thoughts and guidance on practical applications.

3.7. Ecological Recovery

Authors: S. Fisher, R. Woodmansee

Reviewers: J. Karr, P. Brezonik, R. Wentsel

Eight recommendations were made to the authors of the Ecological Recovery paper as

follows:

1. Consider the written pre-meeting comments of the reviewers;

2. Emphasize anthropogenic disturbance and the kind of variation it produces;

3. Stress the importance of monitoring to determine the success of recovery;

4 Stress the uncertainties that exist in recovery;

5. Include case studies to illustrate key concepts;

6. Remove the unnecessary references to ecological theory;

7. Expand coverage of different kinds of stressors; and

8. Include the proper range of disciplines in the discussion of risk assessors.

14
3.8. Uncertainty in Ecological Risk Assessment

Authors: E. Smith, H. Sugart

Reviewers: A.F. Holland, L. Ginzburg, and K. Rose

Ten recommendations were made to the authors of the Uncertainty in Ecological Risk

Assessment paper as follows:

1. Provide more synthesis of the science of characterizing uncertainty;

2. Use a broader variety of examples;

3. Integrate discussions and recommendations with those in other issue papers;

4. Reorganize the introduction section;

5. Refocus the problem definition section;

6. Refocus the analysis-phase uncertainty section;

7. Expand and generalize the discussions in the risk characterization section;

8. Incorporate pre-meeting comments as appropriate;

9. Define terminology used; and

10. Reorganize the describing uncertainty section.

This issue paper defined most of the scientific issues associated with characterizing

uncertainty in ecological risk assessment. It did not, however, bridge the gap between the

general treatment of uncertainty provided by the Framework Report and the specific

information required to develop Agencywide guidance for ecological risk assessment.

3.9. Risk Integration Methods

Authors: R. Wiegert, S. Bartell

Reviewers: J. Bascietto, J. Giesy, P. Van Voris

Four recommendations were made to the authors of the Risk Integration Methods paper

as follows:

1. Revise section formatting;

2. Provide more balance in the discussion of different model groups;

15
3. Include: a discussion of alternative model approaches; and

4. Include: examples of each model approach.

16
4. IDENTIFICATION OF CROSS-CUTTING ISSUES

Concurrent with their review of the individual issue papers, the peer reviewers were

asked to identify cross-cutting issues, those topics common to more than one of the eight

issue papers. Numerous issues were identified in both the pre-meeting comments and during

the breakout sessions. These issues were discussed in the plenary sessions and, to the degree

possible, incorporated by authors into their issue papers or into the introductory chapter to be

added to the issue paper document. Some cross-cutting issues were dismissed, while many

were left to be considered by EPA in its future activities to develop guidelines for ecological

risk assessment. The major cross-cutting issues discussed included:

1. Terminology-Each author was asked to define all terms used in the context of their

issue paper. An alternative, which was rejected, is to create a glossary or a separate

dictionary of terms where the various uses of terms would be defined. It was finally

recommended that when ecological risk assessment guidelines are developed, a

dictionary could be completed to help clarify and unify the terminology.

2. Uncertainty-There was general recognition that many sources of uncertainty exist in

the science of ecological risk assessment, including uncertainty resulting from

selection of modeling approaches and measurement endpoints; assumptions,

extrapolations, and propagation of errors; separating anthropogenic from natural

variation; and year-to-year natural variation in ecological processes. In addition to

recognizing the importance of uncertainty by creating a separate issue paper, all

authors dealt with uncertainty in the context of their papers.

3. Structuring Issue Papers Within the Current Context of the Framework DocumentSome concern was expressed over fitting the issue paper material into the framework

and whether the framework needs modifications. These discussions concluded that

the structure of the framework (problem formulation, analysis, and risk

characterization) was suitable and useful at this time but could, through the iterative

process, undergo some modifications to provide better support for guideline

development.

4. Research-During the review, participants were asked to identify future research

needs within the context of each paper, but not necessarily as a whole. The focus of

the workshop was on the technical quality of the papers to ensure their usefulness in

guideline development. In the process of discussing the papers, future research

topics were noted by the groups. Section 6 of this report summarizes the

recommendations from the reviewers on future research needs.

17
5. Quality Assurance-General discussions were held on the importance of establishing

mechanisms to ensure that the quality of data used in a risk assessment is known and

maximized. Related to these discussions is the concept of data adequacy and the

data quality objective (DQO) process where risk assessors work with risk managers

to determine the degree of confidence needed to make a decision.

6. Complexity and the Need to Simplify-Both the ecological risk assessment process

and the technical content of the issue papers were viewed as being complex.

Workshop participants recognized the need for "simplification" of the ecological risk

assessment process, including identification and use of the right "tools" for

problems; communicating clearly among risk assessors, managers, and society;

deciding which computer software to use to streamline documentation and decision

making; use of an iterative or tiered approach to assessment; and avoiding

conducting an ecological risk assessment beyond the level of ecological significance

required.

18
5. RECOMMENDATIONS FOR DEVELOPING ECOLOGICAL RISK ASSESSMENT

GUIDELINES

5.1. Background and Overview

Following the discussion on the revisions to the issue papers, workshop participants

(reviewers, authors, and observers) were given the opportunity to make suggestions to help

EPA formulate the ecological risk assessment guidelines. This "brain-storming" session was

an open forum on the potential format, structure, and scope of the guidelines that EPA will

be developing in the next year or two. The ecological risk assessment guidelines, much like

the existing human health guidelines, will present the general principles and approaches that

will be used by EPA programs. As such, the guidelines are intended to promote consistency

in the conduct of ecological risk assessments across the Agency while being flexible enough

to allow professional judgment to be exercised. The guidelines will not be textbooks,

cookbooks, or rule books; rather, they will present the preferred procedures and rationales

for an ecological risk assessment.

Workshop participants identified and discussed the value of a number of different

approaches for development of guidelines. Approaches considered included those that rely

on endpoints (e.g., mortality, reproductive and developmental inhibition, etc.); application

type (e.g., new product assessment, land use decisions, dredging, etc.); media (e.g., aquatic,

terrestrial, etc.); or data source (laboratory, field, or model estimation). In conclusion, the

participants agreed that comprehensive guidance is needed now because relying on the

aforementioned approaches to guideline development would be sequential and, therefore,

would greatly lengthen the time required until comprehensive guidance would appear.

The group felt that the practice of ecological risk assessment would improve more

rapidly if the focus of guidance is on the components of risk assessment that are common to

any endpoint, application, media, and data source. Therefore, the recommendation from the

group was that the first guidance document developed be built on the existing Framework

19
Report. Guidance on endpoints, applications, media, and data sources should be

incorporated in this fIrst round of guidance by the liberal use of examples and case studies.

Additionally, it was suggested that guidelines should address other critical elements of

risk assessment such as (1) the defInition of best assessment practices; (2) a more explicit

process for setting assessment goals; and (3) the importance of recognizing that the risk

assessment process is iterative. The best assessment practices should address the

characteristics of a well-performed assessment, which defines the composition and

responsibility of the assessment team; ensures appropriate study design, data adequacy, and

analytical rigor; and builds in effective and clear communication of the process and the

results. The problem formulation phase of the assessment guidelines needs to expand on the

Framework Report, recognizing that assessment goals are selected in the context of social

values and involve public input. In essence, the process of dialogue among the risk assessor,

the public, and the risk manager should be more explicitly explored in the guidance for

problem formulation. The guidelines should also reflect that assessments are more often a

feedback process than a linear analysis, with the iterative nature explained and illustrated in

the guidelines.

This section captures some of the suggestions provided on potential structures of the

guidelines for ecological risk assessment. Section 5.2 presents the ideas of individuals

(Group 1) assembled from several working groups. Section 5.3 provides an overview of the

recommendations from Group 2 (also composed of participants from several working

groups), while subsequent sections (5.4 through 5.9) summarize the recommendations of

individual working groups.

5.2. Recommendations on Guidelines From Summary of Group 1

Basic Principle: If guidelines do not build upon the Framework Report, an alternative

must be developed that is acceptable to EPA.

20
Both guidelines and guidance are needed, and two general models for development of

guidelines/guidance are possible:

• Modell-Develop holistic guidelines and fill in the details for the various elements

of the ecological risk assessment process by preparing supporting documents that are

periodically updated. (See outline in section 5.2.1 below.)

• Model 2-Use the Framework Report as holistic guidance and prepare detailed

guidance for the various elements as stand-alone documents.

The subdivisions to Models 1 and 2 are essentially identical. An outline of Modell is

presented below. Model 2 was disregarded and, therefore, was not fully developed for

presentation. Modell was strongly recommended as the best approach at this juncture.

5.2.1. Modell Outline

1. Introduction

1.1. Historical development of framework (Cube, SIQ2

C)

1.2. Best assessment principles (SIQ2C = Scale Independent

Qualitative/Quantitative Classification)

2. Problem Formulation

Note: Follow framework outline; use issue paper on Conceptual Model

Development

3. Analytical Phase

3.1. Ecosystem Characterization

Note: This section may be better developed in problem formulation.

3.2. Exposure Characterization

3.2.1. Chemical Addition

3.2.1.1. Chemical Stressors

21
3.2.2. Disturbance

3.2.2.1. Biological Stressors

3.2.2.2. Physical Stressors

3.2.2.3. Radiation

3.3. Effects Characterization

3.3.1. Individuals/Populations

3.3.2. Community and Ecosystem

3.3.3. Landscape and Region

4. Risk Characterization

4.1. Risk Estimation

4.2. Risk Description

Note: Rely on issue paper guidance.

5. Interaction Between Risk Assessment and Risk Management

5.2.2. Additional Recommendations

Additional recommendations on supplemental guidance documentation should be taken

from individual Work Group discussion reports, especially those of Exposure and Effects

Characterization. Other ways of approaching supplemental guidance would be to focus on a

matrix that looks at information taken from laboratory, field, or models.

• Case Studies-A significant effort should be made to provide practical guidance

through the incorporation of case studies into the guidance document. Such case

studies will provide continuity through the steps. If case studies cannot be woven

through the document, they should be provided as appendices.

• Framework History-In developing the guidelines, an effort to capture the history of

how the outline of the Framework Report was determined would be beneficial. EPA

has been considering an endpoint/habitat approach, referred to as the "cube" (see

figure 3). The suggestion was made that moving to the Scale Independent

Qualitative and Quantitative Classification Approach could benefit the novice.

22
Ecosystem Types

Organism Population Community Ecosystem

Freshwater

Lakes and Streams

Buffered

Unbuffered

Marine/Estuarine

Coastal

Open Ocean

Terrestrial

Forests

Grasslands

Deserts

Wetland EcosYstems

Freshwater-isolated

Freshwater-flowing

Saltwater marshes

Figure 3. The "Cube"-A Three-Dimensional Matrix of Ecological Risk Organizing

Principles

23
• Balance in Guidelines-The guidelines should seek a balanced level of depth in the

various sections. Each section should provide adequate guidance to b(~ useful

withoUit providing excess detail.

• Tiered Approach-Risk assessments are tiered and activities are often iterative in

nature. This concept should be emphasized in the guidance. In particular, the fact

that risk assessments can be used in a screening fashion will be an important

guidance in focusing the use of risk assessment in pollution prevention programs.

Also, it is important that the guidelines state that the risk assessment process need

not be lengthy.

In conclusion, it was recommended that the guideline writers be familiar with the

recommendations provided at the workshop before embarking on the first draft of the

guidelines. They could also provide an outline of the proposed guidelines and guidance

documents to a core group of experts from this meeting to obtain acceptance. Their help

could be elicite.d in preparing a prioritized strategic plan to developing the guidance as well.

The group could explore:

• Level of detail to pursue guidance;

• Mechanisms for developing supplemental guidelines; and

• Developmental opportunities for technology transfer of guidance.

5.2.3. Best Assessment Practices

Regardless of the model used for development of guidelines, a discussion of "best

assessment practices" should be included in the guidelines that defines:

• Composition and process for assembly of the assessment team;

• Responsibilities of the assessment team;

• Elements of the assessment process;

• Documentation of design assumptions and decisions;

• Communication with risk managers and the public; and

• Other topics related to the mechanics of the process that need to be defined.

24
Best assessment practices should not include detailed guidance on practices for modeling

and analysis methods, data quality determinations, or other technical aspects of the ecological

risk assessment process that have been addressed comprehensively by other organizations

(e.g., the American Society for Testing and Materials). It should simply refer to the

documents prepared by these other organizations.

5.2.4. Goals and Uses ofEcological Risk Assessment

A process for identifying the goals of an ecological risk assessment needs to be

incorporated into the existing Framework Report. This process must incorporate a procedure

to include societal values in selection of endpoints and assessment goals. In this manner, the

ecological risk assessments will be conducted with humans as a part of the ecosystem, not

apart from it.

The need for, and goals of, ecological risk assessments are broad and the guidelines must

be flexible for such diverse uses. The reasons for not constraining ecological risk

assessments to regulatory goals and adopting a "new" ecological goal development process

are: (1) regulatory goals do not allow EPA to be proactive and avoid "train wrecks" or

surprises; (2) the EPA Science Advisory Board Future Risk Report (U.S. EPA, 1988)

identified the major problems facing the nation as ones that were not b~ing effectively

addressed by existing regulations, including biodiversity, habitat modifications, integrity of

ecosystems, etc.; and (3) the public is ready for a new paradigm that makes them a part of

EPA's assessment process and that is both logical and credible. Involving the public in the

process provides some of the credibility needed.

Because the causal· links between changes in ecosystem state and changes in human

welfare cannot be established and modeled, it is essential that the goals generated be

operational applications of social values. These goals should be selected using an interactive

process that involves scientists and the public using a process of value articulation and

conflict resolution. Important points about the goals include:

25
• Goals for ecological risk assessment must be formulated at the appropriate scale;

there is no "one size fits all."

• Goals must make risk assessment part of a broadly focused program of adaptive

management and assessment (Le., they must be challengeable).

• Development of goals for ecological risk assessments should be made in a

consensus-building atmosphere (Holling, 1978). The various groups interested in the

risk assessment should be brought together, and common goals identifi,ed and

expanded.

• Goals should be articulated in terms of the endpoints of the ecological risk

assessment to be conducted.

The existing framework could be modified to include a step for defining ecological goals

and valued ecosystem attributes during the problem formulation stages (Le., the diagram

should explicitly contain an ecological goal development box). This step should include a

feedback loop to risk managers and the conceptual model development elements. Steps in

the development of guidelines and modification of the Framework Report should be taken

incrementally.

5.3. Recommendations on Guidelines From Group 2 (Ecological Significance,

Uncertainty, Risk Integration Groups)

1. Specific guidelines on problem formulation and conceptual model development:

• Be explicit on the contents of the conceptual model, especially on endpoint

selection criteria.

2. Develop several example assessments to illustrate how the principles, c:oncepts, and

issues identified in the issue papers can be applied:

• Include a broad range of examples and problem types;

• Use real world examples when possible; and

• Use hypothetical data if necessary so one can proceed through an entire example

assessment.

3. EPA Program Offices will develop the guidance documents.

26
4. Guidelines should be developed for planning local- and State-scale risk assessments

as well as at State and national scales.

5. Tool development should proceed in parallel with guideline development so the two

are not out of phase, so that when guidelines are developed (Le., in a 10 to 20-year

timeframe, similar to health risk assessment), tools will be available.

5.4. Conceptual Model Development

1. Provide guidelines on conceptmiI model development that are explicit and

instructional.

A. Be explicit about the elements to be considered in a conceptual model (e.g.,

include a checklist); "beef up" issue paper introduction.

B. Develop guidelines on conceptual model development with application-specific

examples. This could be effectively accomplished either with a manual or

software to support:

• Training; and

• Online documentation of decisions.

2. Future guidelines should aim for continuity by using common case studies/data sets.

Note: The case stUdies/data sets could be "representative" (e.g., merged case

studies or created data). .

3. Ensure that. terminology is used consistently and clearly in the guidelines.

4. Do not tinker with the framework. Accept its value in defining basic concepts and

definitions, establishing consi'stency in ecological risk assessment, and as a

communication tool for the nonscientist, but capture and address the conflicts/

controversies in the guidelines.

5.5. Characterization of Exposure

'1. Develop a set of "best assessment practices" for exposure characterization that

provides hands-on or "how to" guidance for key portions of the characterization

(Le., the exposure profile).

27
2. Incorporate in the exposure characterization guidelines the concept of tiers and

additional screening-level approaches for determining when a sufficient amount of

data have been collected and the exposure characterization is adequate.

3. Separate the guidelines for exposure characterization into chemical, physical, and

biological approaches for assessing exposure.

5.6. Effects Characterization

1. The framework exists as an adequate generic risk assessment guideline. To go

beyond what is already captured in the framework will require a series of topical

reports. Topics could include:

• Problem formulation (including a "key" to designing the risk assessment, possibly

evolving into an expert system);

• Exposure (broken down into chemical/physical/biological, air/water/soil);

• Effects (many possible subtopics, perhaps as separate documents, including):

Effects of multiple stressors,

Integration of multiple endpoints,

Qualitative structure-activity relationships (QSAR),

Data analysis and modeling, and

Physical models (microcosms and mesocosms);

• May need separate guidance on chemical and physical stressors; may need

separate guidance for aquatic, marine, and terrestrial systems;

• Data quality and adequacy;

• Risk characterization (including uncertainty); and

• Case histories (unlimited number; illustrate fitting tools to problems).

2. Throughout the guidance documents, the issue of scale-spatial, temporal, and

ecological-should be addressed. This includes the problems of extrapolation across

scales"among taxa, and among ecosystem types.

3. The plan for multiple volumes-topical guidance documents-is based on the vision

of a "toolbox" or "bookshelf." It was the general view that the framework

(modified and improved with age, perhaps, but in essentially its current format)

28
constitutes a generic guideline, the issue papers help to flesh out the guidelines in a

generic way, and the next step has to include more specifics.

Other possible schemes for breaking down the mass of specifics were discussed and

discarded, including:

• By stressor;

• By ecosystem type;

• By endpoint; and

• By application (Le., by problem, or programmatic need).

However, breaking the process down into its components-problem formulation,

exposure and effects analysis, and risk characterization-creates the need for

guidance on fitting the pieces together. Case histories become useful here; they

illustrate how the individual stages and specific tools are applied to particular

problems.

5.7. Biological Stressors

A study that examines the effect of a stressor at all salient levels of scale would help

eliminate the pitfalls caused by "academic blinders." For example, evaluate how a stressor

influences the:

• Individual;

• Deme;

• Population;

• Metapopulation;

• Community;

• Metacommunity; and

• Regional landscape.

The Biological Stressors group preferred not to make a distinction between community

and ecosystem; after all, "ecosystems" without species and "communities" without flows and

flux do not exist.

29
5.8. Ecological Recovery

1. The term "exposure" should be used in the final guidelines with caution. To many

readers it implies the stressor is only a chemical agent, when most .often the stressors

are:

• Physical;

• Chemical;

• Biological; or most likely

• A combination of a variety of stressors.

2. The guidelines should consider that a range of land use alternatives exists, from

protected wildlife reserves to areas intensively harvested, all of which require wise

management and can benefit from the use of ecological risk assessment

methodologies. Although different uses have different management goals, all of the

land use alternatives are concerned with protecting the integrity of natural systems.

3. Any action taken to minimize an ecological risk will have secondary and tertiary

effects as well, and these should be anticipated. The guidelines should encourage

risk managers to consider all potential effects of any action, especially those that

may have a narrow focus to resolve a specific target problem.

4. The guidelines should encourage risk managers to be proactive and not just reactive

in dealing with environmental problems. Whenever possible, efforts should be made

to avoid future problems.

5. While the framework is a good starting point, especially in its inclusion of a broad

set of r..cological goals, it may have some limitations in that its conceptual approach

is based on human health assessments. The specific ecological resources and

conditions that societies wish to protect need to be defined independently of the

current administrative, regulatory, and conceptual structures within ecological risk

assessment. The media approach (air, water, soil) or the regulatory approach

(drinking water, ground water, etc.) should not restrict the conceptual approaches to

protecting ecological resources.

5.9. Uncertainty in Ecological Risk Assessment

1. The guidelines should state that the first step of any ecological risk assessment

should be to define the goals and identify the endpoints of the assessment.

30
2. The guidelines would benefit by including example assessments that apply and

illustrate the concepts in the issue papers. The examples selected should be

demonstrative, cover a range of problem types, and may use "hypothetical" data.

3. Guidelines should be developed so that they can be used as a planning tool.

31

6. FUTURE RESEARCH AND DEVELOPMENT NEEDS

6.1.· Overview

All Work Groups were asked to prepare a list of future research and development needs

as they prepared their comments and recommendations on revising the issue papers. In order

for the ecological risk assessment guidelines to have the beneficial impact that is desired, the

Workshop partipipants strongly recommend that the EPA Office of Research and

Development carefully review the suggested areas needing more research. The research

recommendation~ ~uggested by the participants should be prioritized according to the

contribution each will make to the development of the guidelines. It will also be necessary to

provide the resources necessary to accomplish the research tasks that are judged essential to

the overall success of guideline development. All too often, identified research needs go

unaddressed because resources are not available. Workshop participants encourage the

Agency to take the research needs seriously to fill the gaps to improve the science of

ecological risk assessment. This section summarizes the future research and development

needs identified by the eight Work Groups.

6.2. Ecological Significance

The primary research needs for assessing ecological significance are the development of:

• Tools and guidance for valuihg ecological attributes;

• Procedures for integrating information on ecologic~ endpoints with societal values;

• The environmental risk decision square (the "cubell

) as a decision making tool;

• Procedures and approaches for translating and communicating ecological significance

into the management/decision making/public arena; and

• Monitoring programs established to provide baseline and long-term trend information

for assessing change.

33
6.3. Conceptual Model Development

The Conceptual Model Development group did not identify distinct research needs.

They did, however, see the need for and value of stimulating the development of tools that

could aid in the construction of the conceptual model. A computer-based tool would be

useful to assist with (1) documenting assumptions used in classifying the problem; (2)

summarizing the data on stressor and ecosystem boundaries; (3) selecting endpoints; and (4)

constructing the conceptual model diagram.

6.4. Characterization of Exposure

The primary research and development needs for characterization of exposure are:

• Bioavailability models for chemicals other than nonionic organics;

• Data on interspecies transfer and transfer coefficients for chemicals;

• Better use of existing biomarkers as measures of exposure; and

• Improved ability to assess nonchemical stressors and to increase the exchange of

ideas and information between disturbance ecologists and risk assessors.

6.5. Effects ICharacterization

Future rese.arch and development needs identified for effects characterization are:

• . Methods and concepts for measuring and interpreting effects of sf;ressors on

- Ecosystem stability and equilibrium;

- Nonlinear dynamics in ecosystems and populations;

- Nutrient cycling;

- Disease resistance;

- Diversity; and

- Biotic integrity.

34
• Methods and concepts for measuring and interpreting:

- Effects of fluctuating exposure regimes; and

- Combined effects of physical and chemical stressors.

6.6. Biological Stressors .

Research and development needs for biological stressors are:

1. Organized research efforts, possibly funded by the National Science Foundation and

conducted by doctoral students, into the basic biology and natural history of, risks

from, and predictable effects of the introduction of nonnative species into

ecosystems. It was suggested that a process similar to the Delphi method could be

useful, wherein the experience with similar species will provide the best basis for

researching risks associated with introduced species.

2. Basic microbial research to identify the specific characteristics of bacteria, fungi,

alga, and protozoa that contribute to increased'survival, proliferation, and dispersal.

This information helps accurately predict the risks of introduced species.

3. Develop micro- and mesocosms to more correctly assess the potential dispersal of

microorganisms through air arid biological'vectors. Even though these are the two

major means of dissemination of microorganisms, there is as yet no technology to

assess this phenomenon.

4. Develop in vitro tests, based on microbial traits essential to a successful invasion

(described in #2 above), to correctly assess the impact of introduced species of

microorganisms on major host species. Research in human and veterinary medicine

and plant pathology has identified those traits that indicate a microorganism's

pathogenic potential and which species are likely to be affected. Similar research

needs to be conducted to develop those abilities for evaluating environmental impacts

of microorganisms.

5. Organized research and cataloging should be conducted on the possible processes

and commodities that serve as "corridors" for invasion by many different species of

biological stressors. An example is the current research into ballast water and

commercial logs as invasion means.

35
6.7. Ecological Recovery

Until focus is placed on the ecological goals as discussed and described above and in

comments during the workshop, it was suggested that the most important research priorities

cannot be clearly defined. Ecological sciences have a lot to contribute to this; however, it is

very important that the interests and desires of ecology as a science and the components of

ecology that are most critical to protection of human societal interests in ecological/biological

systems be distmguished. The energies and ideas of ecology and ecologists ner--..d to be more

effectively tapped to accomplish this goal. Further, a variety of societal constituencies needs

to be vested in this process.

6.8. Uncertamty in Ecological Risk Assessment

The following research needs were identified for the topic of characterization of

uncertainty in ecological risk assessment:

• Evaluation of the effect of the independence assumption on the propagation of

errors;

• Evaluation of nonprobabilistic tools on measuring uncertainty in risk assessments;

and

• Evaluation of structural uncertainty using multiple model types.

6.9. Risk Integration Methods

The following research needs were identified for risk integration methods:

• Develop electronic and visual tools (e.g., Terra Vision Model) that will facilitate

easier communication of ecological risk assessment issues, analyses, and results to

policy and decision makers and the public.

36
• Prepare a document to summarize the best contributions from the discipline of

ecology to the field of ecological risk assessment. Answer the following: What

information can be derived from working at the different levels of biological and

ecological organization, or from working at different trophic levels?

• Develop and analyze the functional models for ecological risk assessment that have

policy implications. For example:

1. Nature as a backdrop to human activityObjective: maintenance of equilibrium/homeostasis.

2. Systems are dynamic (covers shorter timeframe, Le., successional issues)-

Objective; maintain the system states within their "natural boundaries." .

3. Systems are evolutionary (covers biodiversity over the much longer term)-

Objective: maintain opportunities for evolutionary adaptation.

37

7. REFERENCES

Boesch, D.F.; Schubel, J.R.; Berstein, B.B.; Eichbaum, W.M.; Barber, W.; Hirsh, A.;

Holland, A.F.; Johnson, K.S.; O'Connor, D.J.; Speer, L.; Wiersma, G.B. (1990)

Managing troubled waters: the role of marine environmental monitoring. National

Academy Press: Washington, DC.

Holling, C.S., ed. (1978) Adaptive environmental management and assessment. John Wiley

and Sons: Chichester, England.

Rose, K.A.; Cook, R.B.; Brenkert, A.L.; Gardner, R.H.; Hettelingh, J.P. (1991) Systematic

comparison of ILWAS, MAGIC, and EDT watershed acidification models. 1. Mapping

among model inputs and deterministic results. Water Resour. Res. 27: 2577-2589.

Suter, G.W.; Barnthouse, L.W.; Bartell, S.M.; Mill, T.; Mackay, D.; Paterson, S. (1993)

Ecological risk assessment. Lewis Publishers: London.

U.S. Environmental Protection Agency. (1994) A review of ecological assessment case

studies from a risk assessment perspective, Volume II. EPA/630/R-94/003, Risk

Assessment Forum, Washington, DC.

U.S. Environmental Protection Agency. (1993a) A review of ecological assessment case

studies from a risk assessment perspective, Volume I. EPA/630/R-92/005, Risk

Assessment Forum, Washington, DC.

U.S. Environmental Protection Agency. (l993b) Draft ecological risk assessment issue

papers. EPA/630/R-93/004A, Risk Assessment Forum, Washington, DC.

U.S. Environmental Protection Agency. (1992a) Framework for ecological risk assessment.

EPA/630/R-92/001, Risk Assessment Forum, Washington, DC.

U.S. Environmental Protection Agency. (1992b) Peer review workshop report on a

framework for ecological risk assessment. EPA/625/3-911022, Risk Assessment Forum,

Washington, DC.

U.S. Environmental Protection Agency. (1992c) Report on the ecological risk assessment

guidelines strategic planning workshop. EPA/630/R-92/002, Risk Assessment Forum,

Washington, DC.

U.S. Environmental Protection Agency. (1991) Summary report on issues in ecological risk

assessment. EPA/625/3-911018, Risk Assessment Forum, Washington, DC.

39
U.S. Environmental Protection Agency. (1988) Future risk: research strategies for the 1990s.

SAB-EC-88-040, Science Advisory Board, Washington, DC.

40
APPENDIX A - REVIEWERS

Risk Assessment Forum

Ecological Risk Assessment Issue Paper Peer Review Workshop

August 16-18, 1994

Reviewers

Workshop Chair:

Work Group Members:

Ecological Significance

Work Group Leader:

General Reviewer:

General Reviewer:

Conceptual Model Development

Work Group Leader:

General Reviewer:

General Reviewer:

Characterization ofExposure

Work Group Leader:

General Reviewer:

General Reviewer:

Effects Characterization

Work Group Leader:

General Reviewer:

General Reviewer:

Biological Stressors

Work Group Leader:

General Reviewer:

General Reviewer:

Dr. Richard A. Kimerle, Monsanto Company

Dr. Kent W. Thornton, FTN Associates

Dr. Robert A. Bachman, Maryland Dept. of

Natural Resources

Dr. Tom O'Connor, National Oceanic and Atmospheric

Administration/NOS

Dr. Gregory R. Biddinger, Exxon USA

Dr. Ronald J. Kendall, Clemson University

Dr. Robert V. O'Neill, Oak Ridge National Laboratory

Dr. William J. Adams, ABC Laboratories

Dr. Lawrence A. Kapustka, Ecological Planning and

Toxicology

Dr. Frederic H. Wagner, Utah State University

OJ;". Jeffrey M. Giddings, Springborn Laboratories

Dr. Nelson Beyer, U.S. Dept. of Interior, National

Biological Survey

Dr. Wayne G. Landis, Western Washington University

Dr. James A. Drake, University of Tennessee

Dr. Richard Orr, U.S. Dept. of Agriculture

Dr. James H. Thorp III, University of Louisville

A-I
Ecological Recovery

Work Group Leader:

General Reviewer:

General Reviewer:

Reviewers (Continued)

Dr. James R. Karr, University of Washington

Dr. Patrick L. Brezonik, University of Minnesota

Dr. Randall Wentsel, U.S. Senate Committee on

Environment and Public Works

General Reviewer:

General Reviewer:

Uncenainty in Ecological Risk Assessment

Work Group Leader: Dr. A. Frederick Holland, South Carolina Marine

Resources Research Institute

Dr. Lev R. Ginzburg, Applied Biomathematics

Dr. Kenneth A. Rose, Oak Ridge National Laboratory

Risk Integration Methods

Work Group Leader:

General Reviewer:

General Reviewer:

Dr. John Bascietto, U.S. Dept. of Energy

Dr. John P. Giesy, Michigan State University

Dr. Peter Van Voris, Battelle-Pacific Northwest

Laboratories

A-2
Risk Assessment Forum

Ecological Risk Assessment Issue Paper Peer Review Workshop

August 16-18, 1994

Reviewers' Names and Addresses

Dr. William J. Adams

ABC Laboratories

7200 East ABC Lane

Columbia, MO 65205

Dr. Robert A. Bachman

Director, Fish, Heritage, and Wildlife

Administration

Maryland Dept. of Natural Resources

Tawes State Office Building

580 Taylor Avenue, E-l

Annapolis, MD 21401

Dr. John Bascietto

U.S. Dept. of Energy (EH-231)

1000 Independence Avenue

Washington, DC 20585

Dr. Nelson Beyer

National Biological Survey

Patuxent Wildlife Research Center

12011 Beech Forest Road

Laurel, MD 20708-4041

Dr. Gregory R. Biddinger

Exxon USA

Benicia Refinery

3400 East Second Street

Benicia, CA 94519

Dr. Patrick L. Brezonik

University of Minnesota

Water Resources Research Center

1518 Cleveland Avenue, Suite 302

St. Paul, MN 55108

A-3

Dr. James A. Drake

University of Tennessee

Dept. of Zoology and

Graduate Program in Ecology

125 Austin Pey Building

Knoxville, TN 37996-0910

Dr. Jeffrey M. Giddings

Springborn Laboratories, Inc.

790 Main Street

Wareham, MA 02571

Dr. John P. Giesy

Michigan State University

Dept. of Fisheries and Wildlife

163 Natural Resources

East Lansing, MI 48824-1222

Dr. Lev R. Ginzburg

Applied Biomathematics

100 North Country Road

Setauket, NY 11733-1345

Dr. A. Frederick Holland

South Carolina Marine Resources Research

Institute

217 Fort Johnson Road

Charleston, SC 29422

Dr. Lawrence A. Kapustka

Ecological Planning and Toxicology

5010 S.W. Hout Street

Corvallis, OR 97333-9540
Risk Assessment Forum

Ecological Risk Assessment Issue Paper Peer Review Workshop

August 16-18, 1994

Reviewers' Names and Addresses

Dr. James R. Karr

University of Washington

Institute for Environmental Studies

Engineering Annex, FM-12

Seattle, WA 98195

Dr. Ronald J. Kendall

Clemson University

The Institute of Wildlife and

Environmental Toxicology

One Tiwet Drive, P.O. Box 709

Pendleton, SC 29670

Dr. Richard A. Kimerle

Monsanto Company

800 North Lindbergh Boulevard

St. Louis, MO 63167

Dr. Wayne G. Landis

Institute of Environmental Toxicology

and Chemistry

Environmental Sciences Building

Room 518

Western Washington University

Bellingham, WA 98225-9180

Dr. Tom O'Connor

National Oceanic and Atmospheric

Administration/NOS

SSMC4, 10th Floor

1035 East-West Highway

Silver Spring, MD 20910

A-4

Dr. Robert V. O'Neill

Oak Ridge National Laboratory

Environmental Sciences Division

Building 1505

Oak Ridge, TN 37831-6038

Dr. Richard Orr

Animal and Plant Health Inspection

Service

U.S. Dept. of Agriculture

Federal Building

6505 Belcrest Road, Room 810

Hyattsville, MD 20782

Dr. Kenneth A. Rose

Environmental Sciences Division

Oak Ridge National Laboratory

P.O. Box 2008, Building 1505, MS 6038

Oak Ridge, TN 37831-6038

Dr. Kent W. Thornton

FTN Associates

3 Innwood Circle, Suite 220

Little Rock, AR 72211

Dr. James H. Thorp III

University of Louisville

Biology Dept.

Louisville, KY 40292
Risk Assessment Forum

Ecological Risk Assessment Issue Paper Peer Review Workshop

August 16-18, 1994

Reviewers' Names and Addresses

Dr. Peter Van Voris

Battelle-Pacific Northwest Laboratories

900 Battelle Boulevard, MS K4-12

Richland, WA 99352

Dr. Frederic H. Wagner

Ecology Center

Utah State University

Logan, UT 84322-5205

Dr. Randall Wentsel

Committee on Environment and

Public Works

415 Hart Senate Office Building

Washington, DC 20510

A-5

APPENDIX B - AUTHORS

Risk Assessment Forum

Ecological Risk Assessment Issue Paper Peer Review Workshop

August 16-18, 1994

Issue Paper Authors

Ecological Significance

Mark Harwell, University of Miami

Bryan Norton, Georgia Institute of Technology

William Cooper, Michigan State

John Gentile, EPA/ORD/ERL, Narragansett, RI

Conceptual Model Development

Lawrence Bamthouse, Oak Ridge National Laboratory

Joel Brown, University of Illinois at Chicago

Characterization ofExposure

Glenn W. Suter II, Oak Ridge National Laboratory

James W. Gillett, Cornell University

Sue Norton, EPA/ORD/OHEA

Effects Characterization

Patrick J. Sheehan, McLaren/Hart

Orie L. Loucks, Miami University, OH

Biological Stressors

Daniel Simberloff, Florida State University

Martin Alexander, Cornell University

Ecological Recovery

Stuart G. Fisher, Arizona State University

Robert Woodmansee, Colorado State University

Uncertainty in Ecological Risk Assessment

Eric P. Smith, Virginia Polytechnic Institute

H.H. Shugart, University of Virginia

Risk Integration Methods

Richard G. Wiegert, University of Georgia

Steven M. Bartell, Senes Oak Ridge, Inc.

B-1
Risk Assessment Forum

Ecological Risk Assessment Issue Paper Peer Review Workshop

August 16-18, 1994

Authors' Names and Addresses

Martin Alexander

Professor, Dept. of Soil, Crop, and

Atmospheric Sciences

Cornell University

708 Bradfield Hall

Ithaca, NY 14853

Lawrence Barnthouse

Leader, Environmental Risk Group

Environmental Sciences Division

Oak Ridge National Laboratory

P.O. Box 2008, Building 1505,

Mailstop 6036

Oak Ridge, TN 37831-6036

Steven M. Barb~ll

Vice President and Director

SENES/Highwood Farm

Old Gobey Road

P.O. Box 688

Wartburg, TN 37887

Joel Brown

Assistant Professor of Biology

Dept. of Biological Sciences

University of Dlinois at Chicago

845 West Taylor Street

Chicago, IL 60607-7060

William E. Cooper

Professor, Institute for Environ.

Toxicology

Michigan State University

C-231 Holden Hall

East Lansing, :MI 48824-1115

B-2

Stuart G. Fisher

Professor, Dept. of Zoology

Arizona State University

University Drive (1501)

Tempe, AZ 85287-1501

John H. Gentile

Environmental Research Laboratory- .

Narragansett

U.S. Environmental Protection Agency

27 Tarzwell Drive

Narragansett, RI 02882

James W. Gillett

Professor of Ecotoxicology

Dept. of Natural Resources

Cornell University

16 Fernow Hall

Ithaca, NY 14853-3001

Mark Harwell

Associate Professor

Marine Biology and Fisheries

Rosenstiel School of Marine and

Atmospheric Science

University of Miami

4600 Rickenbacker Causeway

Miami, FL 33149

Orie Loucks

Eminent Scholar of Ecosystem Ecology

Dept. of Zoology

Miami University

212 Biological Sciences Building

Oxford, OH 45056
Risk Assessment Forum

Ecological Risk Assessment Issue Paper Peer Review Workshop

August 16-18, 1994

Authors' Names and Addresses

Bryan Norton

Professor, School of Public Policy

Georgia Institute of Technology

Atlanta, GA 30332

Sue Norton

Office of Health and Environmental

Assessment

U.S. Environmental Protection Agency

401 M Street, SW (8601)

Washington, DC 20460

Patrick Sheehan

Principal Toxicologist

ChemRisk Division

McLaren/Hart Environmental Engineering

Corporation

1135 Atlantic Avenue

Alameda, CA 94501

H.H. Shugart

WW Corcoran Professor

Dept. of Environmental Sciences

University of Virginia

Clark Hall

Charlottesville, VA 22903

Daniel Simberloff

Robert O. Lawton Distinguished

Prof. of Biological Science

Dept. of Biological Science

Florida State University

109 Conradi Building (B-142)

Tallahassee, FL 32306-2043

B-3

Eric P. Smith

Dept. of Statistics

Virginia Polytechnic Institute and State

University

Blacksburg, VA 24061-0439

Glenn W. Suter II

Research Staff Member

Environmental Sciences Division

Oak Ridge National Laboratory

P.O. Box 2008, Mailstop 6038

Oak Ridge, TN 37831-6038

Richard Wiegert

Professor of Zoology

Dept. of Zoology

University of Georgia

Biological Sciences Building

Athens, GA 30602

Robert Woodmansee

TERRA LAB

315 West Oak Street, Suite 101

Fort Collins, CO 80521

· APPENDIX C - OBSERVERS

Risk Assessment Forum

Ecological Risk Assessment Issue Paper Peer Review Workshop

August 16-18, 1994

Observers' Names and Addresses

Don Barnes

U.S. EPA/SAB

401 M Street, SW

Washington, DC 20460

Kristin Brugger

E.!. Du Pont de Nemours & Company

Experiment Station, Building 402

Wilmington, DE 19880-0402

Joseph Dulka

E.!. Du Pont de Nemours & Company

Agricultural Chemicals Products Division

Wilmington, DE 19880-0038

Scott Dyer

Procter & Gamble

5299 Spring Grove Avenue

Cincinatti, OH 45217

Barbara Elliott

Environment Canada

Commercial Chemicals Branch

351 St. Joseph Boulevard, 14th Floor

Hull, Quebec KIAOH3

William Fisher

Office of Assistant Sec. of Navy

Crystal Plaza 5, Room 236

2211 Jefferson Davis Highway

Arlington, VA 22244

C-l

Andrea Hall

Thompson Publishing

1725 K Street, NW

Washington, DC 20006

Arlene Hamburg

DowElanco

9330 Zionsville Road .

Indianapolis, IN 46268-1053

Kristine Hooks

Compliance Services International

2001 Jefferson Davis Highway

Suite 1010

Arlington, VA 22202-3603

Paul Jacobson

Versar ESM Operations

9200 Rumsey Road

Columbia, MD 21045-1934

Elle Kalketenickri

MARAD

400 7th Street, SW

Washington, DC 20024

William Kappleman

Environ Corporation

4350 N. Fairfax Drive

Arlington, VA 22203
Risk Assessment Forum

E<~ological Risk Assessment Issue Paper Peer Review Workshop

August 16-18, 1994

Observers' Names and Addresses

Donna Kostka

National Biological Survey

MS 3660

1849 C Street, NW

Washington, DC 20240

Tony Maciorowski

Office of Pesticide Programs (7507C)

U.S. EPA

401 M. Street, SW

Washington, DC 20460

Suzanne Marcy

Office of Water (4303)

U.S. EPA

401 M Street, SW

Washington, DC 20460

Dave Mauriello

Environmental Effects Branch (7403)

U.S. EPA

401 M Street, SW

Washington, DC 20460

Corey McDaniel

Los Alamos National Laboratory

K-555

Los Alamos, NM 87544

Tom Parkerton

Exxon Biomedical Services

P.O. CN2350

Mettlers Road

East Millstone, NJ 08875

C-2

W. Bruce Peirano

U.S. EPA

26 W. Martin Luther King Drive

Cincinnati, OH 45268

Kevin Reinert

Rohm and Haas

727 Norristown Road

Springhouse, PA 19477

Bill Richards

Woodward Clyde Federal Services

904 Wind River Drive, Suite 100

Gaithersburg, MD 20878

Don Rodier

Office of Pollution Prevention and Toxics

(7402)

U.S. EPA

401 M Street, SW

Washington, DC 20460

Anne Sergeant

U.S. EPA

401 M Street, SW

Washington, DC 20460

Charles o. Shore

Sciences International

1800 Diagonal Road

Alexandria, VA 22314
Risk Assessment Forum

Ecological Risk Assessment Issue Paper Peer Review Workshop

August 16-18, 1994

Observers' Names and Addresses

Susan Snider

American Forest and Paper Association

1111 19th Street, NW, 8th Floor

Washington, DC 20036

Ralph Stahl

E.!. Du Pont de Nemours & Company

1007 Market Street, B-12212

Wilmington, DE 19898

Dave W. Thompson

General Electric

640 Freedom Business Center

King of Prussia, PA 19406

Bob Vatne

DowElanco

9330 Zionsville Road

Indianapolis, IN 46268

Jennifer Wurzbacher

Hunton & Williams

200 Pennsylvania Avenue, NW

Washington, DC 20006

Paul Zubkoff

Office of Pesticide Programs (7507C)

u.S. EPA

401 M Street, SW

Washington, DC 20460

C-3

APPENDIX D - AGENDA

Risk Assessment Forum

Ecological Risk Assessment Issue Paper Peer Review Workshop

August 16-18, 1994

Radisson Hotel, Alexandria, VA

Agenda

TUESDAY, AUGUST 16

7:30 am Registration and Check-in

Plenary Session

8:30 am

8:45 am

Welcome and Introduction

Dorothy Patton, U.S. EPA, Risk Assessment Forum

Workshop Objectives and Structure

Richard Kimerle, Workshop Chair

Individual Issue Papers

9:00 am

10:30 am

Highlights of Pre-Meeting Comments

Work Group Leaders

Break

Concurrent Working Sessions (8)

10:45 am

12:00 pm

1:30 pm

3:15 pm

3:30 pm

4:00 pm

5:00 pm

Individual Issue Paper Discussions

Work Group Leaders and Reviewers;

Authors Present to Clarify/Discuss

Issues

Lunch

Discussion (continued)

Break

Discussion (continued)

Session Review and Wrap-Up

Adjourn

D-l

The Eight Issue Papers

• Ecological Significance

• Conceptual Model Development

• Characterization of Exposure

• Effects Characterization

• Biological Stressors

• Ecological Recovery

• Uncertainty in Ecological Risk

Assessment

• Risk Integration Methods
Risk Assessment Forum

Ecological Risk Assessment Issue Paper Peer Review Workshop

August 16-18, 1994

Radisson Hotel, Alexandria, VA

Agenda

WEDNESDAY, AUGUST 17

8:30 am

10:00 am

10:15 am

11:15 am

12:15 pm

1:30 pm

2:00 pm

3:30 pm

4:30 pm

5:30 pm

Breakout Sessions

Continuation of Discussions of Issue Papers

Break

!)Ienary Session

Recommendations for Authors

Work Group Leaders

Observer Comments on Issue Paper Recommendations

Lunch

})Ienary Session

Introducing Cross-Cutting Issues

Workshop Chair

Breakout Sessions on Cross-Cutting Issues

Plenary Session

Highlighting Cross-Cutting Issues

Work Group Leaders and Workshop Chair

Observer Comments on Cross-Cutting Issues

Adjourn

D-2
Risk Assessment Forum

Ecological Risk Assessment Issue Paper Peer Review Workshop

August 16-18, 1994

Radisson Hotel, Alexandria, VA

Agenda

THURSDAY, AUGUST 18

8:30 am

9:00 am

10:30 am

11:30 am

12:30 pm

4:00 pm

Plenary Session

Ecological Risk Assessment Guidelines

Dorothy Patton, u.s. EPA, Risk Assessment Forum

Ecological Risk Assessment Guidelines Discussion

Chair, Work Group Leaders, and Authors (Breakouts if needed)

Observer Comments

Lunch

Concurrent Working Groups

Chair and Work Group Leaders: 'Write Workshop Report

Authors: Discuss Revisions to Issue Papers and Schedule

Adjourn

D-3

APPENDIX E - PRE-MEETING COMMENTS

Prior to this workshop, each issue paper was evaluated by a team of three peer

reviewers. This appendix contains both the reviewers' pre-meeting comments and the charge

to the reviewers containing suggested topics for consideration during their review. Versar

and EPA encouraged the reviewers to provide their frank and candid views so that the

authors would have the information needed to complete their papers. Using these written

comments as a starting point, the authors and reviewers collaborated at the workshop and

were able to reach agreement on the necessary revisions for each of the eight issue papers.

(See appendix F.) The revised issue papers are now being compiled and will be published

separately.

Compilation of Pre-Meeting Comments

Contents

Issue Paper and Reviewers Page

1.

2.

3.

4.

5.

6.

7.

8.

Issue Paper Review Topics and

Format for Written Comments

Ecological Significance

Kent W. Thornton

Robert A. Bachman

Thomas P. O'Connor

Conceptual Model Development

Gregory R. Biddinger

Ronald J. Kendall

Robert V. O'Neill

Characterization of Exposure

William J. Adams

Lawrence A. Kapustka

Frederic H. Wagner

Effects Characterization

Jeffrey M. Giddings

Nelson Beyer

Wayne G. Landis

Biological Stressors

James A. Drake

Richard Orr

James H. Thorp

Ecological Recovery

James R. Karr

Patrick L. Brezonik

Randall Wentsel

Uncertainty in Ecological Risk Assessment

Lev R. Ginzburg

Kenneth A. Rose

A. Frederick Holland

E-1

E-3

E-19

E-21

E-29

E-31

E-35

E-37

E-41

E-49

E-53

E-55

E-61

E-69

E-75

E-77

E-85

E-91

E-105

E-107

E-111

E-115

E-119

E-121

E-127

E-133

E-135

E-137

E-143

E-147
Compilation of Pre-Meeting Comments

Contents

(continued)

Issue Paper and Reviewers

9. Risk Integration Methods

John Bascietto

Peter Van Voris

John P. Giesy

10. Cross-Cutting Issues

William J. Adams

Robert A. Bachman

Lev R. Ginzburg

Kent W. Thornton

Frederic H. Wagner

E-2

Page

E-157

E-159

E-163

E-171

E-179

E-181

E-183

E-185

E-195

E-197
Issue Paper Review Topics

and Format for Written Comments

Risk Assessment Forum

Ecological Risk Assessment Issue Paper Peer Review Workshop

August 1994

Background

EPA's Risk Assessment Forum is developing Agency-wide guidance for conducting

ecological risk assessments. The first step in this process was the 1992 publication of

EPA's "Framework for Ecological Risk Assessment (Framework Beport - copy is provided in

Section 5 of this notebook), which proposed a simple, flexible structure, or framework, for

ecological risk assessments. The eight issue papers were written to help provide a basis

for expanding the framework into a more substantive guidance document. The issue

papers authors will be asked to revise their papers based upon comments and

recommendations from this peer review.

The success of this workshop depends on participation of the reviewers. EPA has

asked for your input on the critically important issue of ecological risk assessment. In

order for this to be a fully productive workshop, we will be compiling written comments

from all reviewers prior to the workshop. You will have approximately 10 days to prepare

your written comments and subsequently you will have 10 days to review all of the

comments prior to the workshop.

Areas for Review

Each individual issue paper has a three-person review team that includes a Work

Group Leader and two General Reviewers. Although the full set of issue papers has been

provided to each reviewer for information purposes, General Reviewers are expected to

provide comments only on their assigned paper. Each Reviewer is asked to consider the

following two areas for his or her paper:

• General Areas for Consideration (e.g., completeness; examples, etc.); and

• Questions Relevant to Particular Issue Papers (e.g., how well does a figure

illustrate the concept, are the examples adequate, is there too much detail on

a specific area or not enough?).

In addition, the Workshop Chair and the Work Group Leaders are asked to examine

all the issue papers and comment on:

• Cross-Cutting Issues (e.g.,use of terminology, areas of emphasis, etc.).

E-3
Instructions fen Submission of Pre-Meeting Comments to Versar (due by July 29)

Content:

Format:

The suggested review topics are intended to guide you in your review

of your issue paper. While we ask you to consider the suggested

issues and questions because they reflect specific areas of interest,

you should focus on those topics you feel are most important, and

you are welcome to comment on other topics concerning your paper

as necessary. However, while General Reviewers may comment on

h;sue papers other than their assigned paperI such work is not

assigned and neither Versar nor EPA will reimburse any such work.

To assist the authors in incorporating comments, please refer to the

Review Topic Numbering System (see below) and the page number of

the issue paper.

Where appropriate, please include full citations for references that you

think the authors should consider in revising their papers. Please

f()lIow the citation format used in the Framework Report, for example:

McKim, J.M.; Bradbury, S.P.; Niemi, G.J. (1987). Fish acute toxicity

syndromes and their use in the QSAR approach to hazard assessment.

Environmental Health Perspectives 71: 171-186.

Submit a hard popy of your comments, and, if possible, a disk copy of

your comments saved in Wordperfect 5.1 (or higher) format.

Due Date: Friday, July 29, 1994 -- It is essential that Versar rec4~ive comments

by the due date so that the comments can be complied and sent to all

workshop participants to allow for review of all the comments prior to

the workshop.

E-4
Instructions for Submission of Pre-Meeting Comments (continued)

Review Topic Numbering System

In an effort to facilitate discussion of particular topics the suggested review topics

are given a two-part number as follows:

The first part of the number refers to the to which the topic refers:

G- = 2- = C- =

General Area;

Issue Paper Number (refer to page numbers); and

Cross-Cutting Issues.

The second part of the number refers to the specific number of the topic as

presented in the following list of topics:

G-6

2-2

C-1

=

=

=

Topic #6 listed in the General Area topics (i.e.,

"Examples")

Topic #2 in Issue Paper Number 2 (Ecological

Significance); and

Topic #1 in Cross-Cutting Issues ("Terminology").

E-5
General Area,s for Consideration

Reviewers should consider the following factors:

G-1. Clarity of purpose and scope. Comment on the utility of the introduction as

a ltroad map" to the organization and major emphasis of the paper.

G-2. Completeness of coverage. Ideally, each paper should address issues

spanning the fuJI range of ecological risk assessments (different stressors,

ecosystem types, levels of ecological organization, and spatial and temporal

scales). Without necessarily expanding the volume of the report, which of

these Clreas (or others) deserve more (or less) coverage?

G-3. Clarity and consistency of terminology. Comment on the definition of terms

and th(~ need for a glossary.

G-4. Current capabilities vs. future needs. What areas should be expanded (or

condensed) so that the paper covers both current scientific capabilities (the

"givens") and future research needs? While key literature references should

be cited, descriptions of background information already in the literature

should be minimized. Promising approaches that will require additional

research should be clearly separated from presently available techniques.

G-5. Relationship to EPA's Framework for ecological risk assessment. How could

the authors improve discussion of the applicability (or inapplicability) of the

framework approach?

G-6. Examples. Where could additional examples be useful for clarifying or

illustrating the application of principles?

E-6
Questions Relevant to Particular Issue Papers

Preliminary review and discussion of the issue papers identified many areas

where additional work was required. The time available for revision was quite

limited, and some papers were completed with more unresolved issues than others.

Consequently, the number of questions provided below for each paper is also

variable. Reviewers are encouraged to provide their views on the questions

relevant to their assigned paper as well as to identify other areas where the issue

papers can be improved.

2. Ecological Significance

2-1 . Comment on the balance between ecological and social aspects of this

paper.

2-2. Should a glossary be provided with this paper? If so, what terms should be

included?

2-3. What additional criteria, if any, could be provided to help differentiate

between ecologically significant and insignificant changes?

2-4. At what additional places in the paper, if any, could examples be used to

illustrate concepts?

E-7
Questions Relevant to Particular Issue Papers (continued)

3. Conceptual Model Development

3-1 • Comment on how the balance of the paper should be changed in the

following areas, if at all. Please be specific on what should be added or

deleted.

3-1 a. Chemical vs. non-chemical stressors.

3-1 b. Perspectives from different levels of biological organization -

individual, population, community, and ecosystem levels.

3-1 c. Stressor characterization vs. ecosystem at risk, endpoints, and the

conceptual model.

3-2. How might the case study examples be better integrated into the paper to

illustrate the concepts discussed?

3-3. What additional clarification is required (if any) for the terms. "stress regime,"

"disturbance regime," and "regulatory endpoint?"

3-4. Comment on the adequacy of discussion of the time scale to be addressed in

an ecological risk as~essment.

E-8
Questions Relevant to Particular Issue Papers (continued)

4. Characterization ofExposure

4-1. Terminology has been a controversial area especially for this paper. Which

'e~posure-relatedterms are most appropriate for the range of chemical and

non-chemical stressors encountered in ecological risk assessment? (See text

box for one set of alternative terms. Also, refer to Figure 1 in the paper).

4-2. The discussion of disturbances is short compared with chemical exposures.

What technical issues should be covered in more detail in the disturbance

section (e;g., fragmentation or natural disturbance characterization)?

4-3. How well do figures 2 through 6 reflect the structure used to assess

exposure? What other types of exposures are not addressed?

4-4. Page 4-13 lists three primary exposure considerations during problem

formulation. What modifications, if any, do these considerations require?

4-5. Page 4-22 lists three primary objectives of the exposure assessment in the

analysis phase. What modifications, if any, do these objectives require?

4-6. Page 4-26 states that the objective of most chemical exposure analyses is to

estimate the concentration of chemicals in different media at equilibrium.

What modification, if any, does this objective require?

E-9
Questions Relevant to Particular Issue Papers (continued)

4. CharaG:terization ofExposure (continued)

One Set of Alternative Exposure Terms

The terms listed below were synthesized from discussions among the issue paper authors

and from a consultation with EPA's Science Advisory Board (SAB). The terms differ in

varying degrees from those in the Framework Report and the Exposure issue paper.

Source: An entity or action that releases to the environmental or imposes on the

environmental a chemical, physical, or biological agent.

Agent: The physical, chemical, or biological entity that is first released to or imposed upon

the environment from a source. An agent does not necessarily directly induce adverse

responses but may generate "secondary" stressors that can induce such responses.

Stressor: Any physical, chemical, or biological entity that can induce an adverse response.

The stressor may be the agent or may be derived from interactions between the agent and

the ecological system.

The use of the terms agent and stressor was not clearly resolved in the discussions. Our

interpretation is that while the terms are very similar, they differ in connotation as described

above.

Stress Regimg: The exposure andlor disturbance that results from interactions of stressors

with ecological components. Stress regime is defined in terms of spatial extent, intensity,

duration, and frequency, and is used in place of "Characterization of Exposure."

Exposure: Co-occurrence of or contact between an ecological component and a stressor

added to an ecological system.' Stressors included in this definition may be chemical,

physical, or biological additions (e.g., thermal discharge to a stream, exotic species

introductions).

Disturbance: Co-occurrence of or contact between an ecological component and a stressor

that modifies or deletes part of an ecological system. Such stressors may be physical (e.g.,

habitat destruction or alteration in natural fire or hydrologic cycles) or biological (e.g.,

species removal by harvesting).

There is not an absolute distinction between exposure and disturbance. For example,

sedimentation in a stream may be considered as an addition-type stressor or as a

modification to stream morphology.

4-7. Section 3.2 provides considerable detail on chemical fate and transport.

Which areas, if any, should be deleted?

4-8. Page 4-9 discusses prospective and retrospective assessments; page 4-18

discusses effects-driven and source-driven assessments. Are these

classific:ations appropriate and useful for consideration of assessment types?

4-9. Knowledge gaps are listed on page 4-49. What gaps, if any, should be

added to or deleted from this list?

E-lO
Questions Relevant to Particular Issue Papers (continued)

5. Effects Characterization

5-1 . What changes, if any, should be made in the relative emphasis on different

levels of biological organization - individual, population, community, or

ecosystem?

5-2. How should the paper be modified, if at all, to better reflect present

capabilities vs. areas for future research and research needs?

E-ll
Questions Relevant to Particular Issue Papers (continued)

6. Biological Stressors

6-1 • COmmt3nt on the balance in the paper between discussion of geneticallyengineered microbes and exotic species "macrobes. II

6-2. Risk assessments of biological stressors will have to be done even though,

as the paper indicates, our present ability to make accurate predictions may

be verv limited. What more could be added concerning how such risk

assessments should be approached now and what future research needs are

in this area?

E-12
Questions Relevant to Particular Issue Papers (continued)

7. Ecological Recovery

7-1. What additional examples of recovery in ecosystem types not described in

this paper, if any, could be added to illustrate specific points in the text?

7-2. What more could be added concerning recovery from anthropogenic (as

opposed to natural) stressors?

7-3. What additional tools and methods available to risk assessors to analyze

whether recovery has occurred, if any, could be included in this paper?

What are the relative strengths and weaknesses of these approaches?

7-4. How well does the paper address the socio-economic factors that affect the

likelihood of recovery?

7-5. What additional information, if any, is available on recovery at the landscape

level?

E-13
Questions Rel13vant to Particular Issue Papers (continued)

8. Uncerta'inty in Ecological Risk Assessment

8-1 . This paper tends to focus on quantitative estimates of uncertainty. What is

the proper balance between qualitative, quasi-quantitative, and quantitative

uncertainty estimates in the risk assessment process? What additional

examplE~s could be provided to illustrate these approaches?

E-14
Questions Relevant to Particular Issue Papers (continued)

9. Risk Integration Methods

9-1 . Physical and experimental models are included as risk integration tools. Is

this correct, or should these models be considered as analysis phase

methods?

9-2. What examples can be provided regarding the application of fuzzy set theory

to ecological risk assessments?

9-3. How (if at all) should the paper be changed to better differentiate current

capabilities from future research needs?

9-4. What should be added (if anything) to the discussion of the weight of

evidence approach (section 5.3)?

9-5. What changes, if any, should be made in the balance between the various

sections of the report?

E-IS
Cross-Cutting Issues

These topics (and others to

be identified by workshop

participants) will be discussed

during the second part of the

workshop. The Risk Assessment

Forum is especially interested in

comments and recommendations

that will assist writers of future

Agency-wide ecological risk

assessment guidelines to address

these difficult issues.

Exposure Terminology

C-1. The Characterization of

Exposure issue paper

propOSE~S one set of

exposure terms, the text

box associated with

question 4-1 shows

another, and the Framework

Report provides a third.

Which terms are most

appropriate for the range of

stressors encountered in

ecologif::al risk assessment?

Why? {See also figures 1

through 6 in the

Characterization of

Exposure issue paper for

exampl13s of a range of

situations that exposure

terminology should

address),

Modifications Recommended by the SAB to

EPA's Framework Process Diagrams

Note that terminology changes associated

with exposure discussed in question C-'J are

repeated here. Figures are those found in the

Framework Report.

II Overall Process (figure 1)

Move the data acquisition, verification, and

monitoring box inside the overall ecological

risk assessment box.

Extend the box with the dotted line separating

exposure and effects into the problem

formulation and risk characterization phases,

and eliminate the vertical arrows extending

from problem formulation into risk

characterization.

II Problem Formulation (figure 2)

Modify the diagram to emphasize the central

role of conceptual model development. Show

endpoint selection as an output of the

conceptual model, not an input to it.

Use "ecological system" instead of

"ecosystem."

Use a two-way rather than a one-way arrow

between risk characterization and the data

acquisition box.

II Analysis (figure 3)

Eliminate the boxes for exposure and stressorresponse profiles, or show them as outputs of

the process.

Show a feedback arrow from the analysis

phase to the conceptual model.

II Risk Characterization (figure 4)

In the risk description box, eliminate the

"Jnterpretation of Ecological Significance";

this subject is described by "Ecological Risk

Summary,"

E-16
Cross-Cutting Issues (continued)

EPA's Framework for Ecological Risk Assessment

C-2. The basic pattern for the issue papers is derived from the Framework Report.

EPA's SAB and others have suggested modifications in the framework (see

text box on previous page). Which changes, if any, would improve either

the consistency among the issue papers or the general applicability of the

framework to the full range of ecological risk assessments?

C-3. Comment on the applicability of EPA's framework for biological stressors.

What modifications to the framework, if any, are required?

C-4. Are prospective, retrospective, effects-driven, and source-driven

assessments adequately differentiated and discussed?

C-5. Are the dimensions of exposure adequately discussed (e.g., from the

standpoint of experimental design)?

C-6. What, if anything, should be added concerning the issues of bioavailability

and environmentally-realistic exposure in toxicity tests discussed?

C-7. Should there be increased emphasis on anthropogenic disturbances? How

and where could this be incorporated into the issue papers?

If you have any questions or need additional guidance regarding any matter

pertinent to submission of your comments, please contact:

David Bottimore, Versar

703/750-3000 extension 378

E-17

Ecological Significance

Workgroup Leader:

General Reviewer:

General Reviewer:

Dr. Kent W. Thornton

FTN Associates

Dr. Robert A. Bachman

Maryland DNR

Dr. Tom O'Connor

National Oceanic and Atmospheric

Administration/NOS

E-19

Issue Paper 2: Ecological Significance Review Comments - 28 July 1994

Authors:

Reviewer:

M. Harwell, University of Miami

B. Norton, Georgia Institute of Technology

W. Cooper, Michigan State University, and

J. Gentile, US EPA ERL-Narragansett

Kent Thornton, FTN Associates, Ltd.

INTRODUCTION

The review follows the general format requested by EPA and Versar. However, two

additional sections, General Comments and Specific Comments, have been added prior to

the Cross-Cutting Issues. These sections include review comments that are considered

germane to the Issue Paper but can not be satisfactorily incorporated under General Areas for

Consideration or Specific Questions. These comments refer primarily to general

organization, clarification of specific Issue Paper statements, and/or alternative considerations

or points of view. I recognize the short time frame for revision, the need to minimize major

reorganizations to the Issue Papers, and that many of these comments might not be addressed

in this Issue Paper, but could, perhaps, be considered during guideline development.

GENERAL AREAS FOR CONSIDERATION

G-l. Clarity of Purpose and Scope

The Introduction clearly states there are no formulas or guidelines for determining

ecological significance. It also identifies some of the factors that influence ecological

significance, but there is no clear definition or definitive statement of ecological significance.

Because this is such a difficult subject or issue to address, a working defInition should be

provided in the Introduction. The two attributes of ecological significance listed in the third

paragraph on page 2-9 might be revised to provide this working definition. Ecological

significance also is used differently throughout the text. This is discussed further below.

The Introduction does provide a list of central themes that will be discussed in subsequent

sections, but the central themes identified on page 2-10 do not correspond to the following

sections. Revising these bullets to reflect the content of the subsequent sections would assist

the reader. A possible revision might be:

B-21
Issue Paper 2: Ecological Significance Review Comments - 28 July 1994

• Introducing the concept of ecological significance and interaction of scientific

and societal values during problem formulation

• Attributes of stressors, exposures and effects that contribute to ecological

significance that should be considered during analysis

• Integrating societal values, analysis results and uncertainty in assessing ecological

significance, and

• Providing information on ecological significance to decision makers.

Comple:teness of Covera~e

In general, the Issue Paper is relatively complete in its coverage. It does discuss different

stressors, ecosystem types, levels of ecological organization and spatial/temporal scales. It has

a nice discussion of natural and anthropogenic stresses and the importance of considering both

in determining ecological significance. The discussion of levels of ecological organization in

Section 3.2.1. 1.. identifies populations, communities, and ecosystems, but does not contain, a

paragraph on landscapes. Landscape ecology and its importance for assessing ecological

significance is discussed throughout the text, but it is not specifically identified as an important

level of organi2:ation. For completeness, this paragraph should be added. A table summarizing

the important attributes of each organizational level would be a useful addition. Given the

importance of habitat alteration as a major stressor, the authors might want to include a few

additional sentences on physical stressors.

Reference or baseline conditions are introduced in Subsection 3.2.2 Recovery (last

paragraph in Subsection, p 2-37, just preceding Subsection 3.2.3). Reference or baseline

conditions might be expanded and introduced in earlier sections as another metric for assessing

ecological condition. This might include the substitution of space for time in providing baseline

or reference conditions on various seres Qr successional stages of ecological systems.

Establishing or identifying reference sites might be considered part of problem formulation,

while also con.tributing to the analysis and risk characterization phases.

There is considerable redundancy in the Issue Paper. Clearly, reiterating points

emphasizes their importance and reinforces these factors for the reader. However, the authors

might consider reducing the text during revision to eliminate some of this redundancy. There

are also some areas where the paper might be shortened. For example, Section 2. Problem

Formulation could be shortened and still maintain its salient points, particularly if the Appendix

is retained as part of this Issue Paper.

Clarity and Consistency of Terminolo~y

As stated above in Comment G-l, a definition of ecological significance should be

provided in the Introduction. The elements and factors contributing to ecological significance

are provided throughout the text, but it should be defined initially. There are some places in

the text where ecological significance appears to be synonymous with scientific significance and

other places where it appears to be determined only by societal factors. These discrepancies

should be resolved.

E-22
Issue Paper 2: Ecological Significance Review Comments - 28 July 1994

There are several terms that are used in the text that should be defined in a glossary. All

of the terms used in Table 2 should be defined, if the table is retained in the Issue Paper.

Additional terms might include fungible, intergenerational equity, resistance, ecological

endpoints, assessment endpoints and measurement endpoints.

In several subsections, the critical point(s), which are quite good, are made at the end

of the paragraph or subsection (e.g., last sentence of middle paragraph on p 2-31; last paragraph

on Community level, p 2-32; last paragraph on Ecosystem level, p 2-33; last paragraph on

3.2.1.4. Timeframe for Change, p 2-35; middle paragraph on p 2-40 in 4.1 Societal Values).

I personally think the Issue Paper would be strengthened if these critical statements were used

to initiate the paragraph or section. I would suggest the authors review their respective sections

during revision to see if there are other important statements or paragraphs that could be moved

to the beginning of the section/subsection, followed by the illustrative examples.

G-4. Current Capabilities vs Future Needs

The Issue Paper states in the Introduction that there currently are not formal or accepted

guidelines or approaches for assessing ecological significance. There is some discussion of how

economists assess significance and selected discussion of current approaches for assigning value

to different factors contributing to ecological significance, but there is limited discussion of how

ecological significance is currently assigned to various ecological changes and impacts. An area

that could be strengthened in the Issue Paper would be a subsection on how ecological

significance is currently determined and how this information is used in the decision-making

process. This discussion also should include the relation of ecological significance to policy and

decision-makers perspectives and endpoints. The Issue Paper develops criteria and factors'that

should be considered in determining ecological significance and presents some excellent

examples of how these individual criteria or factors have been applied. Supplementing this with

a brief subsection on how these factors are currently integrated in the Risk Characterization

phase to assess ecological significance or how ecological significance is currently transmitted to

the decision maker/manager would be useful.

In general, the Issue Paper does not explicitly identify Future Needs. Two exceptions

are a statement of the need to develop the risk typology structure and Subsection 5.4, Research

in Support of Decision-Making, which has only two generic research areas listed. Clearly there

are other areas where research is needed to assess ecological significance such as the

establishment of ranges of nominal and subnominal scores for various measurement and

assessment endpoints, procedures for associating or integrating ecological and economic criteria,

the importance of establishing cause-effect relationships in assessing ecological significance or

formulating the hyperspace or hypervolume of the risk typology structure in assessing ecological

significance.

G-5. Relationship to EPA's Framework for Ecoloeical Risk Assessment

The Issue Paper clearly relates ecological significance to the EPA Framework for

Ecological Risk Assessment and each of the 3 primary phases. This relationship, in part, has

E-23
Issue Paper 2: Ecological Significance

resulted in considerable redundancy among Sections because many of the same factors are

discussed in Problem Formulation, Analysis and Risk Characterization. One possible approach

to reduce this redundancy, albeit at the expense of reorganizing the Paper, would be to have

Section 2 specifically define and discuss ecological significance and the need for assessments for

different stressors, ecological types, levels or organization, etc; Section 3 discuss the factors that

are important in determining or influencing ecological significance; Section 4 relate these factors

to the three phases of Ecological Risk Assessment; and Section 5 discuss the input of ecological

significance to decision-making.

Examp'es

The authors have done an excellent job of providing examples in the text that illustrate

why various factors/criteria/attributes are important in determining ecological significance. I do

not think additional examples are required in the text. However, the figures and tables should

be revised for greater clarity. In particular, the captions on most figures and tables do not

provide an explanation of the illustration. Specific examples are:

• Table 2. Without a phrase providing a definition of these terms, it is not always

clear why they are equivalent concepts.

• Figure 2. Without clarification in the caption, this figure eludes me. It also was

110t clear from the text how this hierarchy was formulated or what it meant.

• Figure 3. Again, the caption is critical. This is a center piece of Section 2 and

raised again in subsequent sections. It should have an explanatory caption. In

addition, it is not at all clear, from the figure or the text (the Appendix does

provide the explanation) how time and space are incorporated in this figure.

• Figure 4. Expand the caption to explain the figure.

• Figures 5, 6. and 7. Personally, I would not include these in the Issue Paper.

)[ don't think they provide a good illustration of the concept in the text and think

they would require significant explanation for individuals to understand.

• Figure 8. This figure does not illustrate or clarify the concept presented in the

text without further explanation. The immediate impression is that you have 5

independent pathways for the development of different climax associations,

starting from an upland brush grass perennial system. It is not clear exactly what

is intended from this figure.

• Figure 9. Without additional information in the caption, much of the information

in this figure will be lost on the reader. For example, P/R is not defined, the 0.5

meters, 10 meters, ... 700 meters are not defined as stream width, CPOM,

FPOM are not defined, changes in fish types are difficult to discern, etc.

• Figure 10. I am not sure this figure captures the significance of biogeochemical

cycles that was intended in the text. There are better figures that describe the

phosphorus cycle at multiple scales from an individual lake watershed to basin to

E-24
Issue Paper 2: Ecological Significance Review Comments - 28 July 1994

region to global cycle that would probably provide a better example. I will bring

an example with me to the review meeting.

The authors identify a number of factors in each section/subsection that are important to

consider in evaluating ecological significance. I think it would be useful to the audience ifthese

could be summarized in a text table, with a brief paraphrase to refresh the readers memory on

re-reading or provide the individual skimming the document with an overview of the important

factors for each issue or topic. These could also be incorporated as text bullets, but the table

would be preferred.

G-7 General Comments

While this section was not specifically requested, the categories identified above do not

permit discussing aspects of organization and general content. There is considerable disparity

among the general organization and content of individual sections. For example, the central

theme is unclear in Section 2 and the concepts of ecological and social/societal significance are

intermixed and confusing (in sharp contrast to the Appendix); Section 3 contains a number of

"provocative" statements that are not referenced or fully supported through discussion; Section

4 is more clearly written with directed information and ideas; while parts ofSection 5 are weak

and not well-developed. The Issue Paper could be improved if a single author revised the

document and developed each section similarly. Specific comments are presented in another

section of this review.

QUESTIONS RELEVANT TO ISSUE PAPER 2: ECOLOGICAL SIGNIFICANCE

2-1. Balance Between Ecolo(:ical and Social Aspects of Si(:nificance

This raises the issue discussed in G-l and G-3 above. Ecological significance

incorporates both scientific and social significance, as indicated in the text. The authors have

provided a good, balanced discussion of the importance of considering not only the scientifically

measured changes or impacts in ecological systems and their components but also the

consideration of what this change/impact means from a societal perspective. However, there

is limited discussion on the relationship of ecological significance from a .policy or·decisionmakers perspective. The difficulty of integrating multiple perspectives to develop a statement

of ecological significance also is well-documented in the Issue Paper.

2-2. Glossary and Terms

This was discussed in G-3 above.

2-3. Additional Criteria for Differentiatin(: Sif:nificant vs Insi~nificant Chanf:e

The Issue Paper identifies a number of criteria that might be used to differentiate

significant from insignificant change. The Issue Paper is strongly oriented toward sustainability,

which is not necessarily a problem, but sustainability as a unifying principle is subject to debate

in the scientific community.

E-25
Issue Paper 2: F..cological Significance

Existinl: and Additional Examples

This was addressed in G-6 above.

Review Comments - 28 July 1994

SPECIFIC COMMENTS ON ISSUE PAPER 2: ECOLOGICAL SIGNIFICANCE

Specific comments on Issue Paper 2 are raised in the chronological order noted in the

text.

1. p 2-6, 2nd line. Is risk assessment only a construct in which the risks from human

activity can be assessed or does it also included the concept of relative comparison (Le.,

relative risk) and differentiation of natural causes or sources?

2. p 2-6 to 2-7. The four bullets listed do not have equivalent footing for supporting the

basic emphasis on significance. The first two are essentially truisms; the third is

conjecture; and the fourth is the premise on which the paper is based. Little

uncomfortable presenting these as having the same factual basis.

3. p 2-7 to 2-8. Ecological significance is comprised of two components: societal values

(judgements) and scientific information, I think, is what is intended in the text on pages

2-7 and 2-8. You might be able to combine these two paragraphs, or abbreviate them

with this initial statement.

4. p 2-8 to 2-9. What I might infer from this text on statistical versus ecological

significance is that statistics has no role in determining the significance of any outcome

in ecological risk assessment (Le., "Relying on stringent statistical tests is not compatible

with this flexible paradigm. "). There is little disagreement that statistical significance

is not nlxessarily required for ecological significance and vice versa, but there clearly

is a role for statistical tests, analyses, and statements in ecological risk assessment and

in support of ecological significance. There is nothing magic about a 95% CI and

making decisions. Most wildlife management studies would never be published if they

required. a 95% CI to show statistical significance. Meta-analysis, while not firmly

established in the literature, is an approach for combining multiple studies to provide

additional weight of evidence. I think you can eliminate the discussion in the second

paragraph on p 2-9 and not diminish the strength of your argument. .

5. P 2-11. The Problem Formulation section discusses the importance of considering

ecological significance at the initiation of the assessment. Absolutely agree. However,

there is no discussion of the importance of problem definition, question generation and

bounding the problem as part of focusing the assessment on the ecologically significant

issues. There is no other Issue Paper on Problem Formulation. Is it worth a few

sentences to acknowledge the critical importance of this phase of ecological risk

assessment? This section also could be tightened and shortened, I think, without losing

its salient points or diminishing the importance of the phase. This is particularly true if

the Appendix is retained. "

6. P 2-12. The analogy with human health is interesting and, as you know, controversial.

I personally like the analogy, but others do not. If you chose to retain this analogy, there

are two issues you might address. First, you state in the middle of the page that

E-26
Issue Paper 2: Ecological Significance Review Comments - 28 July 1994

ecological management is only vaguely analogous to health management, but then

develop this analogy in the first paragraph of the next sectiO!1 on Science and Public

Interaction. The preceding paragraph does not really support the use of this analogy.

Second, you state that both societal values and science are involved in·a physicians

judgement regarding whether a patient is healthy or ill. Why do societal values influence

a physician's judgement on health and illness? The Surgeon General's office rarely

solicits public opinion on what const~tutes public hea;lth, but does attempt to influence

public opinion on what individuals should consider to be good public health. The

analogy presented in the paragraph does not appear to be appropriate for assessing

ecological health

7. P 2-18 to 2-20. The Risk typology is intriguing. It seems to imply that there is a sector

somewhere in this hyperspace where criteIia should be able to be defined so that there

is almost universal agreement that further stress can not be assimilated/accommodated.

Outside this minima, different societal values compete for use ofthe resource and societal

values take on greater weighting than scientific assessments of impacts. Would be

interesting to pursue as part of the guidelines.

8. p 2-21. The last paragraph represents a critical part of the Section. The authors should

consider introducing this early in the section.

9. p 2-23, last paragraph before 3.1.2 "Natural stress, in essence, is divergence from the

normal physical and chemical regime of an ecosystem; ecological significance results

from such divergence". What does this mean?

10. p 2-29. Section 3.2.1.1 Ecological Components of Change and Ecological Endpoints.

Why is this section included in Analysis? Identifying endpoints is an integral part of the

Problem Formulation phase. Should this section not be moved to the Problem

Formulation section? In addition, how are ecological endpoints different from assessment

or measurement endpoints? I assume that these "ecological" endpoints embody and

represent the information the public/decision makers/managers will use ~o reach a

decision on significance. This is a critical part of problem formulation .. There is a

statement at the end of the first paragraph in this section that I do not understand. "If

none of the stress-induced changes (direct or indirect) in an ecological system involve the

selected ecological endpoints, then the change has ecological significance. If some

endpoints are affected, however, then other considerations must apply for determining

ecological significance". Please explain this.

11. P 2-34, Section 3.2.1.3.. I like the subsection, but it is out of context with the other

subsections. It says ecological significance increases with the area affected because:

bullet, bullet, bullet. End of story. There are interesting contrasts in subsections

throughout the Issue Paper. Having one author or a technical editor revise the document

would be helpful.

12. p 2-42 to 2-43. 4.2.2 Uncertainty. There is no mention of sampling, interannual,

measurement, analytical or other sources of error included in sources of uncertainty.

E-27
Issue Paper 2: l&:cological Significance Review Comments - 28 July 1994

Was there a reason why these were not considered part of uncertainty? In addition, I

would reinforce and emphasize the statement you make at the end of the paragraph

immediately following the bullets - the risk manager must have a clear and

comprehensive presentation of all the assumptions in the assessment. This is rarely done

and almost never done well. Assumptions are inherent in every bit of information from

a laboratory study to field data collection to the statistical/empirica1Jprocess model used

in the analysis. I encourage you to emphasize the importance of this in assessing

ecological significance.

13. p 2-46, 5.1 Weight of Evidence. The statement is made that risk communication is

beyond the scope of this chapter. I think communication is similar to ecological

significance; if it is not considered during every phase of ecological risk assessment,

clear, concise and understandable information will not be provided as input to the

decision maker. Can information be ecologically significant if the individual/parties

receiving it can not understand it?

14. P 2-48 to 2-49. These three sections, 5.2, 5.3 and 5.4 are weak. I would suggest you

consider adding some of the conclusions arising from the EPRI/EPA Joint Climate

Project to Address Decision Makers' Uncertainties in place ofsections 5.2. and 5.3. The

citation is: Science and Policy Associates. 1992. Joint Climate Project to Address

Decision Makers' Uncertainties. TR-100772. Electric Power Research Institute. Palo

Alto, CA. The research needs should be enhanced to discuss the techniques, studies and

procedures identified as part of the Issue Paper needed to develop useful guidelines for

determining ecological ·significance.

E-28
Ecological Risk Assessment Issue Paper

Pre-meeting Comments

Reviewer: Dr. Robert A. Bachman

Issue Paper: Ecological significance

General Areas for Consideration

G-1. The introduction clearly outlines the relationship of

the paper to the Framework and the function of the paper.

G-2. The paper spans the full range of the ecological risk

assessment process. Areas for further clarification are

discussed under comments 2-1 and 2-3.

G-3. Terms appear to be SUfficiently defined. No glossary

needed.

G-4. The manner in which societal values are evaluated and

incorporated into problem formulation is poorly articulated,

perhaps because of the lack of understanding on just how this

process can be objectively assessed. See more on this in

comments 2-1 and 2-3.

G-5. The paper appropriately expands on the framework

approach.

G-6. The examples are helpful and adequate to illustrate

the principles discussed.

2-1. Except for some ambiguity regarding initial or

benchmark conditions, the ecological or ecosystem function

analysis appears to be fairly well articulated. It is unclear,

however, just how the social aspects will ever be fully

integrated into the risk assessment procedure. The authors

acknowledge this on page 2-54.

It is unclear why the discussion regarding public values

affecting ecological significance are included as an appendix to

the issue paper instead of being incorporated into the main body

of the paper. The authors correctly assert that "Defining what

is ecologically significant partially involves the judgement of

society-at-Iarge••• " (page 2-7). Because the question of whether

the effect of a stressor matters or not so frequently depends

upon the perspective or will of society, it raises the question

of whether it is practically possible to formally incorporate

this line of inquiry into the risk assessment process or not.

For example, if society at large perceives human population

growth and economic growth as desirable, a particular stress may

be considered insignificant. On the other hand, if and when

growth is perceived as undesirable, the same stress could be

considered very significant indeed. Because most ecosystems can

E-29
be considered as a "commons" in the Hardin (1968) sense, how is

the risk al;sessor or risk manager to take this ambiguity into

account?

2-2. No glossary needed.

2-3. The issue paper could be strengthened by more clearly defining baseline assumptions or sideboards for endpoint

selection. . For example, although the authors acknowledge on page

2-16 that 1:he ecosystem's place on a continuum is important,

there is little reference that many, if not most, ecosystems in

the united states are in various states of disequilibrium. Most

if not alII' rivers and streams currently experience stormwater

runoff events (floods) that are larger than the long-term events

that shaped the morphology of the stream and river beds. stream

bank erosicm from decades and even centuries of anthropogenic

activity have set in motion physical stresses that will take

further decades to check or restore. Other ecosystems, such as

forests set aside for succession to old-growth systems are in

various stages of recovery. The ecological significance of a

stress may depend upon the definition of the ecosystem status and

trend selec:ted for assessment. If extant conditions are used as

reference, the stress may be considered insignificant, Whereas if

pre-Columbi.an, or pre-human conditions are considered as the

baseline ccmdition, the same stress might be extremely

significant~.

2-4. Examples are clear, and adequate.

Reference:

Hardin, G. (1968) The tragedy of the commons. Science 162:1243-

1248.

E-30
Review of Issue Paper on Ecological Significance

Thomas P. O'Connor

Introductory comment

The February 1992 Framework for Ecological Risk Assessment clearly states

the need to set eeological endpoints as the essential first step in problem

fonnulation. It defines such an endpoint as -an explicit expression of the

. environmental value that is to be protected.- The words -ecological significancedo not appear until the second to last page of the Framework document in the

context of communicating results of a risk assessment. Aspects to be

COnsidered are magnitude of effect, spatial and temporal scale) and recovery

time. Two or three paragraphs are then devoted to each aspect. The EPA

Scientific Advisory Board's August 1992 report reviewed the Framework, and a

li.st of proposed issue papers. Other than recommending that the topic of

natural variability be address separately, the SAB said nothing about the

proposed issue paper on Ecological Significance. The SAB, though, was very

keen on the way the Framework highlighted the importance of problem

fonnulation. This leaves me convinced that the importance of defining endpoints

is. recognized, but wondering whether -ecological significanceu comes into play

when defining. endpoints or only when communicating results. Since most

people ~ould prefer to not to be assessing the risk of insignificant ecological

modifications~ I will proceed on the assumption that considerations of "-

environmental significance are part of problem definition. However. since the

same considerations may well be covered in all the other issue papers, there

may be no need for a separate paper on this topic.

G-1 Clarity

The reader is left with no more guidance to significance than what is already in

the Framework where it indicates that considerations of magnitude of effect,

spatial and temporal scale, and recovery time are central to its detennination. I

have not read any other issue papers but the Tables of Contents of four of them

also specify these considerations. This issue paper repeats the list three times,

once under the heading of ·Problem FonnulationD

, once under the heading of

-Analysis·, once again under the heading of -Risk Communication.· These

sections, themselves, are inappropriate because the topic at hand is not an

entire risk assessment. It would be better to have one section for each of the

criteria deemed necessary for a declaration of significance.

To some extent clarity is lost because. as stated on page 19, ·While the goal of

this chapter is to give more specificity to this criteria, we recognize that many

particulars can only be filled in with ecosystem-specific infonnation...- It is ,

difficult to maintain a solely general discussion, and this may be why the

authors have allowed themselves many digressions. There is a lot of space

devoted to the decision process and to the utility of economics as a gUide to

public regard for the environment. All this diverts the reader from getting to

guidance on determining ecological significance. Similarly there are all sorts of

E-31
referenCE~ to ecosystems with different spatial scales. different recovery times,

different ~evels of resiliency, and so forth. This misses the mark, too, because it

does not address the main question. The paper would benefit from I,eing much

shorter.

There are some insights that go beyond the FrameWOrk document. Figure 3 is

helpful but axes shourd be identified On the horizontal axis, I think recovery

time decrease from infinity at the left to zero at the right (it would be more

conventic)nal to have it increasing from left to right). On the vertical, spatial

extent varies from very local at the bottom to global at the top Better still, using

the notion on pages 25 and 34, the vertical axis could be 0 to 1 representing

the fractional extent of an entire system. The idea on pages 19 and 28 that·

sustainability is a critical characteristic of an ecosystem deserving protection

was not introduced in the FrameWOrk. Similarly, the concept of redundancy on

page 35 brings out the fact that species shifts•. in and of themselves. may not be

significant.

G-2 Completeness

The main issue is to put some criteria on the intensity, scale, and recovery rate

of an eoo,logical change required to make it a ·significant- change. Those

criteria are not prOVided.

G-3 CJa~and consistency of tenninoJogy

I found nc) difficulties in this regard. Terms of jargon are either explained here

or in the Framework document.

G-4 Cummt capabilities vs. future needs

The criteria for ·significancell remain undefined.

G-5 Relationship to EPNs Framework for Ecological Risk Asse~sment

The pape·r clearly derives from the issue of -ecological significanceb'first raised

in the Framework. However. it does not prOVide further guidance

G-6 Examples

It would help immensely if the authors could provide at least one eX~lmple

where thE~ ecological significance of a man-made non-global environmental

change is assessed. They should show how considerations of intensity, scale,

and recovery time were brought to bear in at least one specific case not

involving species extinction.

E-32
2-1 Balance between ecological and social aspects

I think that too much of this issue paper is devoted to social aspects~ Certainly

societal values determine what is going to be protected, but those endpoints are

not necessarily ecological much less -ecologically significant". The risk

managers, dealing directly with the pUblic, have to consider every possible

effect raised by the citi2enry. If upon review, using the still-to·be-formulated

gUidelines, a non human-health endpoint is deemed -ecologically insignificant-.

the risk manager has to convey that conclusion to the public. In this arena

science conflicts with public perception and the strength of the guidelines are

tested. However, it is circular to require societal acceptance as part of the

guidelines.

It easy to imagine pUblic concem over effects that are not -ecologically

significant- because they occur over small scales or are ephemeral or both.

Even if public pressure forces a decision to be based on such a concern, it does

not become -ecologically significant". Conversely, a century ago wetlands did

not enjoy today's public sentiment toward conservation but that did not make

them less ecologically significant The first order of business is to set guidelines

for lIecological significance- independent of societal perceptions.

2-2 Should glossary be inclyded

No

2-3 What additional criteria

No criteria are provided.

2-4 At what additional places could examples be used

All Figures, save #3, can be deleted. Figures 1, 2 and 4 deal with decision

making, not ecological significance. Rgures 5, 6, and 7 concern details of

popUlation dynamics by themselves and in the presence of stress. The

variables are not explained in the text, but even if they were, this is much too

much detail on one type of response to stress. Figure 8 is like the previous

three in being unexplained but also too detailed. Figure 10 on the

biogeochemical cycle of elements is too far afield.

E-33

Conceptual Model Development

Workgroup Leader:

General Reviewer:

General Reviewer:

Dr. Gregory R. Biddinger

Exxon

Dr. Ronald J. Kendall

Clemson University

Dr. Robert V. O'Neill

Oak Ridge National Laboratory

E-35

WRITTEN COMMENTS

ON

CONCEPTUAL MODEL DEVELOPMENT

GREGORY R. BIDDINGER

GENERAL AREAS FOR CONSIDERATION

G-1 Clarity of purpose and scope

The introduction of the issue paper is where I would expect to find the definition of the scope of

information to be covered in the following pages and identification of the purpose for which the

information is needed. I did not find that provided in the introduction. What the reader does get is a nice

concise introduction to what the conceptual model is or accomplishes in relationship to the Problem

Formulation phase of the USEPA Framework for Ecological Risk Assessment". The historical context

is well presented and the reader is given a clear image of how the conceptual model fits in the

framework. but not the road map to the rest of the issue paper. A one sentence purpose statement is

provided.

" The purpose of this chapter is to discuss the translation of agreed-upon values and goals into

technically credible and cost-effective risk assessments."

In my estimation this statement is too cryptic to be a core idea that the reader carries with them

throughout the entire issue paper. To me the purpose of the issue paper is more along the lines of the

following:

The purpose ofthis review will be to explain the relevance ofthe conceptual model to a

credible risk assessment, and to -demonstrate (with 2 case studies) how the conceptual model

changes in relationship to the stress regime. ecosystem components at risk and regulatory

objectives.

This then could be followed with a statement of scope that says how it will be done.

In order to achieve these objective stressor characteristics and types ofstressors will be

reviewed to better understand how the conceptual model will change with different stress

regimes. As well the importance ofthe regulatory context in which the risk assessment is

performed will be reviewed to show how it inffuences the selection ofendpoints and defines the

bounds for the ecosystems at risk. All ofwhich adds up to the potential for dramatically different

conceptual models for the same set ofenvironmental conditions.

Obviously. the authors can do a better job than I have done above, but the introduction could benefit

from a concise statement of purpose and scope.

G-2 Completeness of coverage

I feel like the authors did a good job of coverage and with the exception of the limited number of

examples selected (see comments in G-6 below) I have no objections with the breadth of materials

presented.

G-3 Clarity and consistency of terminology

There were a number of ecological terms with which I was not very familiar(e.g. vagility) which were

defined within the context of a sentence or example. This left me guessing at times about the

E-37
meanings. I don't think you should bog down the text with the definitions. 'would suggest a glossary all

in one section or key term boxes through out the text in areas where they are used.

G-4 Current (:apabilities vs. future needs

The development of capabilities in conceptual model formation is really a function of our understanding

of how the world works. The more we know about ecosystems and the way we perturb them the better

we will be able to identify risks and how to estimate their probabilities.

What I might suguest would be worth pursuing would be the development of tools which could help the

risk assessor assure that they have fully explored all the considerations impinging on the development of

their particular conceptual model. This could be in the form of a set of rule-based questions which guide

the modeler through a system of checks and balances flesh out their model. The conceptual model and

the problem formulation phase in which it is imbedded deserve their own guidance document. The

aforementioned nde-based questions could be developed as part of that guidance.

G-5 Relatiom;hip to EPA's Framework for ecological risk assessment

I believe the auth()rs have been true to the framework in the development of the issue paper. Their

terminology and presentation of the key concepts parallels the framework document

G-6 Examples

The examples chosen were useful in helping to see the way the conceptual model is shaped and the

flexibility of the risl( manager and risk assessor in performing a risk assessment. I would like to have

had more examples of other kinds of stressors. If there is to be a guidance document on problem

formulation then examples of conceptual models for each stressor type should be included.

In general, I approve of the way in which the examples where used to provide continuity through out the

entire paper. One problem I did note with these specific examples was that neither had any selection

criteria and qualit~, assurance standards for the models and data used. Due to that fact the issue paper

comes up short on its guidance in this area. The brief section (6.4) on page 3-53 is 1I10t very informative.

At a minimum this section should be expanded and a example be included to address this critical

element of the conceptual model.

E-38
3~ Conceptual Model Development

3-1 Comment on how the balance of the paper should be changed in the following areas, if at all.

Please be specific on what should be added or deleted.

note the comments listed below really address the issue of balance between sections and not

specific points of difference I might take within specific sections.. I will identify those issues separately

and bring them to the workshop with me. If time allows I will share with authors and co-reviewers in

advance of the workshop.

one major issue is that a glossary would be a great help. Whether each paper needs a glossary will

depend on how papers are finally published; as a collection or individual documents.

3-1a Chemical vs. non-chemical stressors

There seems to be adequate balance between the two areas. In the first reading I thought there was

more detail than I needed in the chemical stressor sections and the physical stressors was difficult to

follow. In rereading it was obvious to me this was due to the fact I know more about chemical stressors

than physical ones (e.g. habitat loss)

3-1 b Perspectives from different levels of biological organization - individual, population,

community, and ecosystem levels.

The issue of level of organization for the assessment was integrated effectively throughout the issue

paper. On the other hand the treatment in section 4.2 on page 3-37 was very cursory and not very

useful. Therefore a reader/user of the document will be disappointed if he/she expects to find that

guidance in one location. If the sponsors want the issue papers to be that level of guidance then this

section and others like it should be expanded.

3-1 c Stressor characterization vs. ecosystem at risk, endpoints, and the conceptual model

In general I don't see any great imbalance among these sections each seems to layout the details of

issues to be considered.

3-2 How might the case study examples be better integrated into the paper to illustrate the

concepts discussed ?

As I stated above in the general comments (G-6) I think the two case studies were systematically woven

through the issue paper in an way which provide needed continuity. Also, as previously stated, the case

studies were inadequate in supporting a clarification of the model/data selection criteria and quality

assurance standards

3-3 What additional clarification is required (if any) for the terms "stress regime", disturbance

regime", and "regulatory endpoint" ?

The term stress regime was not clearly defined as far as I could tell from reviewing the document.

Section 3 on characterizing the stress regime did provide an adequate overview of what the aspects

which define the regime. These aspects include the type of stressor, the source of the stress, and the

pattern with which an exposure to the stress occurs. A clear definition in the introductory paragraphs

would be useful. The sentence could be as simple as

The stress regime is the totality ofstress related characteristics which include the type

and source ofthe stressor; the stressors pattern ofexposure (intensify, frequency, duration, and

timing) and the spatial scale in which the stressor is operating

E-39
Although not dire(~ly stated in the text, my interpretation of the concept of a disturbance regime is that

it Is a specific type of stress regime which addresses physical stress effects (habitat loss or distruction).

The text Implies that it is unique from other stress regimes because there is a natural background level of

disturbance which introduces a background risk load and it is the consequences of the incremental risk

burden from anthropogenic disturbances that upset the balance. I believe that chemical ~1ressors also

have a background or even competing risk from compensatory mortality associated with disease, and

predation. althou~lh we seldom consider this in our risk estimates.

Although. I couldn't find a separate definition of regulatory endpoint the definition was intuitive from the

numerous reference though out text that the conceptual model would be effected by the regulatory

context In which It was developed. From the discussion in section 5. it was apparent that a good

regulatory endpoint was one which (1) was susceptible to the stressor; (2) demonstrated ecological

relevance; (3) satisfied the risk manager as support for regulatory policy and (4) was in alignment with

societal values and public opinion.

3-4 Comments on the adequacy of discussion of the time scale to be addressed in an ecological

risk assessment.

The related issues of exposure pattern, duration and timing where really dealt with at a very general

level. They were very direct and a good encapsulation of the main considerations but with out any

depth. I think if I were about to embark on the development of a conceptual model I could spend a few

minutes reading through this and be reminded of some very key issues qUite efficiently. But if I need to

explore the Influence of time scale on my specific assessment I would have to look elsewhere for help,

and I am not sure that is not appropriate. .

E-40
RISK ASSESSMENT FORUM

ECOLOGICAL RISK ASSESSMENT ISSUE PAPER

PEER REVIEW WORKSHOP

August 1994

Comments provided ~y:

Ronald J. Kendall, Ph.D.

TIWET/Clemson university

Clemson, SC

on the Paper

"CONCEPTUAL MODEL DEVELOPMENT"

prepared by

Lawrence Barnthouse

Environmental sciences Division

Oak Ridge National Laboratory

Oak Ridge, TN

and

Joel Brown

Department of Biological Sciences

university of Illinois at chicago

chicago, IL

E-41
GENERAL COMMENTS and AREAS FOR CONSIDERATION

The Is.sue Paper, "Conceptual Model Development" by Barnthouse

and Brown (1994) is a well written document that provides some

appropriate examples of chemical and non-chemical stressors in the

context of an ecological risk assessment. Overall, the paper reads

very well and is relatively easy to complete in a short period of

time. However, in consideration that this Issue Paper will provide

some important guidance to future individuals that will be

developing ecological risk assessments, at least one more example

should be included for comparison. I would suggest that in

addition to the (1) pesticide issues and birds and (2) the forest

wetlands study, I would recommend including one additional example

of a hazardous waste site ecological risk assessment. This will be

explained more fully in my technical review of the paper. I also

believe that the paper should be enhanced in terms of scientific

style and presentation with appropriate citation of more peerreviewed scientific articles. This would enhance the communication

of technical information and, where appropriate, examples might be

found for further clarification of the literature. I think that

the paper entitled "Conceptual Model Development" by Barnthouse and

Brown (1994) provides a good foundation for critical review and

further refinement.

E-42
1. SPECIFIC QUESTIONS

DEVELOPMENT:

RELEVANT TO CONCEPTUAL MODEL

1a. Chemical vs. non-chemical stressors.

I think the carbofuran example in birds is a good use of a

data rich pesticide example for wildlife exposure. Additional

appropriate literature should be cited (Mineau 1993; HUdson, et ale

1984). In addition, I would suggest broadening the reader to

include other pertinent examples of ecological risk assessment of

pesticides (Avian Effects Dialogue Group 1989, 1994; Smith 1987).

A good example is also represented by Kendall and Akerman (1992).

In addition to the pesticide/wildlife issues, I would suggest an

example in the "Conceptual Model Development" Issue Paper to

include hazardous waste site exposure and food chain contamination

in wildlife.

The Louisiana Forest Wetland Study example is valuable to

present as a non-chemical stressor in the present document. With

these three examples, one would be able to move through a

pesticide-wildlife issue with a product that breaks down relatively

quickly in the environment, next one could consider food chain

contamination related to hazardous waste issues in both birds and

mammals with appropriate questions asked, and then move into a nonchemical stressor in the example of the Louisiana Forest Wetland

Study.

1b. Perspectives from different levels

orqanization - individual, population,

ecosystem levels.

of biological

community, and

In the present document entitled u'Conceptual Model

Development", referenc.:~ is made to various levels of impact on

E-43
biological organization, including on individual, population,

community and ecosystem levels. In the carbofuran-'bird example,

there is not a very good tie between individual impacts in terms of

mortality and population ecology. For this reason, I would refer

the authors to the book by Kendall & Lacher (1994) entitled

"Wildlife Toxicology and Population Modelling: Integrated studies

of Aqroecolsystemsil that has a considerable amount of referenced

information on individual impacts of pesticides in birdE~ and other

wildlife and investigation of the relationship between individual

impacts and impacts at the population level. In addition, with the

suggested Ilazardous waste study, the authors would be able to tie

together food web contamination with impacts at the population and

community levels. A good example would be Giesy, et al. (1994).

1c. !Jtressor characterization vs. ecosYstem at risk,

Jmdpoints, and the conceptual model.

In thE~ Issue Paper entitled "Conceptual Model Development",

the authors do a relatively good job in tying together concepts

such as stressor characterization versus ecosystems at risk and

appropriate endpoints t;o measure in context with development of the

conceptual model. I think the addition of one more example (e.g.

hazardous wastes) would enhance the ability within the paper to

communicate these concepts to a less informed reader. In addition,

more discussion should '~lucidate appropriate endpoints and testable

hypotheses as a function of the stressor charact.erization and

concern for various ecosystems at risk. At the present time, this

is somewhere between a blend of art and science and as much

discussion and presentation of relevant examples as pOpl:3ible would

E-44
enhance transforming this "art form" to a stronger scientific base.

~. HOW MIGHT THE CASE STUDY EXAMPLES BE BETTER INTEGRATED . INTO THS PAPER TO ILLUSTRATE THE CONCEPTS DISCUSSED?

In regards to the question of how case study examples might be

better integrated into the Paper, I think that· the current two

examples in the "Conceptual Model Development" Issue. Paper are

already well integrated. The additional example already suggested,

including hazardous waste sites, would probably be best included as

the second example among the three. The lead off example with

carbofuran and birds as a pesticide case does well as a data rich

scenario to be used as the first case example. The concluding nonchemical stressor paper, particularly the Louisiana Bottomland!

Wetlands Paper probably takes position number three in a lineup.

3. .WHAT ADDITIONAL CLARIFICATION IS REQUIRED (IF ANY) FOR

THE TERMS "STRESS REGIME," "DISTURBANCE REGIME," AND

"REGULATORY ENDPOINT?" ..

All of these terms represent additional terminology which must

be appropriately defined and consistently used. One of the

difficulties in developing consistency in ecological risk

assessment has been re~ated to inadequate definition of terms and

inconsistent use of even defined terminology. Just the topic

"stress regime" is a relatively vague term, particularly in

toxicological definition. For this reason, it will be extremely

import~nt for the authors to define and compare and contrast these

various terminologies and how they are referenced and utilized in

the "Conceptual Model Development".

4. In terms of comment on the adequacy of the discussion of

the tim~ scale to be addressed in an ecological risk assessment,

E-45
this can be debated against other issues of similar importance,

including l3tressor int~nsity, frequency, duration, timing, scale

and modes of action. These particular stressor characteristics are

outlined well in the text; however, better referencinl:;J of these

characteristics would improve scientific quality considerably.

5. Sl?ECIFIC RECOMMENDATIONS.

1. 011. Page 3-5 on Line 6, remove "a concrete plan" and the

sentence should read: "In short, the conceptual model serves as a

focusing process for conducting the analysis phase of the

assessment and defines the types and quantity of information

available for risk characterization".

2. On Page 3-7, Line 11, I would suggest replace the word

It illuminatE~1t with the \<Tord "reveal".

3. On Page 3-22, in Section 3.3.1.1. "Pesticides", several

references are made co "toxins" which are really poisonous

substances derived from a natural origin such as the venom of a

spider. "Toxics" mor~ clearly describe a pesticide as a toxic

substance.

GENERAL CONCLUSIONS and SUMMARY

In addition to inclusion of ailother case example in terms of

the examples presented as case studies in the "Conceptual Model

Development" paper, a stronger orientation to scientific

referencing should be included in the document. For instance,

there are some exce:.lent literature sources for carbofuran

ecological risk assessment for birds. In addition to scientific

refereed material, there also exists several document:s produced

E-46
through the Avian Effects Dialogue Group of the Conservation

Foundation and later Resolve which dealt with the issues of

pesticide impacts on birds and their populations (Avian Effects

Dialogue Group 1989, 1994). Kendall (1992) presents information on

pesticide exposure in birds in context with ecological risk

assessment which could contribute to the present manuscript. The

figures in the Conceptual Model Development paper really do not add

anything at present in terms of showing Conceptual Model

Development and the moving from there to an analysis stage. I

would suggest that the authors give consideration to more

appropriate utilization of figures which would show the development

of the conceptual model process and how one would use that

information to move clearly into the analysis stage. This would

enhance the reader's understanding of the use of the Framework

Document for Ecological Risk Assessment that I believe EPA wants to

elucidate with the Issue Paper. Overall, I believe the authors

presented a good document to work from and to be utilized in the

future harmonization of the ecological risk assessment process

within EPA.

Respectfully submitted,

Ronald J. Kendall, Ph.D.

E-47
LITERATURE

Avian Effects Dialogue Group. (1989) ~P~e~s~t~i~C~l~·d~e~s~~a~n~d~-=B~i~r~d~s~:

Improving Impact Assessment. Conservation Foundation,

Washington, D.C.

Avian Effec:ts Dialogue Group. (1994) Assessing Pesticide Impacts

on Birds: Final Report of the Avian Effects Dialogue Group.

1988-1993. Resolve, Washington, D.C.

Giesy, J.P., J.P. LudwIg and D.E. Tillitt. (1994) Deformities in

Birds in the Great Lakes Region: Assigning Casualtv.

Environmental Science and Technology 28(3):128A-135A.

Hudson, R.H., R.K. Tucker, and M.A. Haegele. (1984) Handbook of

Toxicity of Pesticides to Wildlife. 2nd ed. united States

Department of the Interior Fish and wildlife Service.

Resource Publication 153. Washington, D.C.

Kendall, R.J. and J. Akerman. (1992) Terrestrial wildlife Exposed

to Agrochemicals: .. An Ecological Risk Assessment Perspective.

Environmental Toxicology and Chemistry 11(12):1727-1749.

Kendall, R.J. and T.E. Lacher, Jr. Eds. (1994) wildlife

Toxicology and PopUlation Modeling: Integrated Studies of

Agroecosystems. Lewis Publishers. Boca Raton, 579 pp.

Kendall, R.J. (1992) "Farming with agrochemicals: The response of

wildli.fe." Environmental Science & Technology. 26(2) :238-

245.

Mineau, P. (1993) The Hazard of Carbofuran to Birds and other

Vertebrate Wildlife. National wildlife Research Centre,

Canadian wildlife Service, Technical Report CW69-5/177E.

ottawa.

smith, G.J.. (1993) Pesticide Use and Toxicology in R.elation to

Wildlife: Organophosphorus and Carbamate Compounds. United

States Department of Interior, Resource .Publication 170.

C.K. Smoley, Boca Raton. 171pp.

E-48
COMMENTS ON 3. CONCEPTUAL MODEL DEVELOPMENT by Barnthouse and

Brown.

Review by Robert V. OINeill, ORNL

I intuit that the pupose of writing these papers was to fill out

and make more practical the principles developed in the Purple

Framework.

handcuffs!

The real danger is that the report becomes Grape

I think all of the authors should consider whether

they have taken this opportunity to push back the boundries of

our understanding of Risk Assessment or merely filled in the

blanks in previous thinking. Risk is a brand new baby - let's

help it grow and develop, not define it so that it is constrained

to remain a baby.

In chapter/paper 3, the development of a conceptual model is

discussed as a process that helps focus thinking and makes

explicit the stressors, the system, the endpoints, etc.

Everything that follows in the risk assessment will fall back on

this probl~m definition stage. So nothing may be omitted,

nothing forgotten~ at this formulation step.

The chapter is designed, therefore, to be comprehensive. The

authors have done a very professional job in trying to encompass

every eventuality in their presentation. But the task is a

daunting one they are essentially asked to write a textbook in

ecology. The paper will be cross-examined for omission

anything that is omitted may damn the adequacy of what follows.

The problem is not unique to the chapter, it is implicit in the

E-49
assessment task. The authors have approached this problem in a

experientiall manner: liThe following example shows that a

particular type of effect occurs, therefore, don't forget to

include it in your thin~dng. II Based on past eHperience, here is

a way to proceed that does not repeat the mistakes of the past.

But the most important information to be extracted from past

experience is that new and unanticipated phenomena are arising

continuously. You cannot include everything - you certainly

cannot include what you don't know about! Society's

responsibility is to act responsibly - not infallibly.

The most important aspect of the conceptual model phase is WHAT

YOU LEAVE OUT! !! T~e paper currently attempts to list candidates

for inclusion I really wanted to see principles for leaving

factors out. I think the chapter (and the preceeding one as

well) would benefit by some discussion of how one decides to

leave something out of the analysis - without violating the need

to act responsibly.

So the problem becomes developing principles that ensure that all

relevant processes and state variable are included. The authors'

approach to this problem is encyclopedic: here is everything I

have experienced or has occurred to me while I wrote this paper.

Can we go past that? Instead of a checklist, can we develop

principles? WOUld it be possible to catalogue the TYPES of

effects propagation? Is there a taxonomy of effects types?

E-SO
There is no discussion o·f mOI"'s "esoteric" pot.ential effects, such

as mOVing the system toward a point of instability or

bifurcation, even though changes in individual components of the

system are within acceptable bounds. How about esoteric

cumulative effects: habitat fragmentation that will at some point

in the future make it difficult for the region to maintain

species diversity even though the present project cannot be shown

to causa this effect right now? Is it worth talking about

several conceptual models: one with direct and secondary

processes with impacts directly tracable to the project being

assessed - and another level of analysis that might consider

societal/economic changes that will cause a drift toward

undesired endpoints or interactions with unrelated stressors?

Just how far does the conceptual phase go? Non-violation pf

existing laws? No known impact (based on our experience)? Don't

we need to go toward cost-benefit and quality of life? Where

does it end? Should the conceptual model phase include

evaluation of the costs of mitigating if the system eventually

shows negative impacts? Should this be a cost to the developer?

- maybe in escrow? Just where does the process end?

This paper and the preceeding one overlap in scope - both attempt

to bec:omprehensive - beth advocat.e that the broadest possible

view be taken. Although I have not be given time to adequately

go through the preceeding paper, I believe I detect significant

overlaps that should be cleared up.

E-51
The only real defect in the paper is in section 3: Characterizing

the Stress Regime. The material is too finely divided into

subsections. Eliminate all paragraphs that contain a single

declarativl~ sentence followed by: "For eHample ••• II ~1uch of the

material can be tabulated. Focus on principles and not on

details and examples. The outline of the section is fine, the

execution is too tedious. The authors should aim at

restructuring this section into 5 pages instead of 20.

E-52
Characterization of Exposure

Workgroup Leader:

General Reviewer:

General Reviewer:

Dr. William J. Adams

ABC Labs

Dr. Lawrence A. Kaputska>

Ecological Planning and Toxicology

Dr. Frederic H. Wagner

Utah State University

E-53

4.0 Characterization of Exposure

William. J. Adams

General Areas for Consideration (as pertaining to exposure characterization)

G-l. Clarity of purpose and scope

Overall, the introduction provides a reasonable starting point for the paper on

characterization of exposure. However, I believe it is lacking some organization that

could improve its ability to serve as a "road map" to the organization and major

emphasis of the paper. I believe the paper should strictly follow the major concepts and

components of risk assessment provided in the Framework document. For example,

characterization of exposure is predominantly dealt with in "Problem Formulation" under

the headings of stressor characteristics and concepmal model and in the "Analysis"

section of the risk assessment Framework (see Figure 3, page 18 of the Framework

document) under the headings of stressor characterization, exposure analysis, and

exposure pro:fI1e. At a minimum, a summary should be provided which ties back to the

Framework document and lists the same "headings" for characterization of exposure,

i.e., Problem Formulation (stressor characteristics and conceptual model) and Analysis

(stressor characterization, exposure analysis, and exposure profIle). One could carry this

further and organize the introduction around these headings although this is not essential.

I feel very strongly that these same headings need to be used in the Table of Contents

and as headings in the body of this paper. Most of them are currently there, but in a

slightly· modified form. I would like the road map to be more clear starting with the

Framework document.

G-2. Completeness of coverage

I think the authors did a good job of laying down the basics for conducting risk

assessments for multiple types of stressors and ecosystems. It is difficult to cover this

subject in great detail in a few pages. Perhaps the paper could be enhanced by a further

discussion of how characterization of exposure should be performed at the population

and community level. I would also like a little more discussion on preparation of

exposure profIles with an example or two.

G-3. Clarity and consistency of tenninology

(1) The glossary is clearly needed and was nicely prepared, although I did

comment on one or more defmitions.

(2) There is a need for some standardization of terms not only in this paper, but in

the· Framework as well. The use of exposure characterization, stressor

E-55
characterization, exposure analysis, stressor regime, appear to be used

interchangeably at times. Some standardization has to be established which cuts

across all of the papers and the Framework. I suggest that EPA review the

recommendations ofthe SAB, past and present workshop participants and prepare

a standard glossary of terms and edit all documents to be consistent with these

terms.

G-4. Current Capabilities Versus future needs

Ifyou read the characterization of exposure paper from the view point of a scientist who

wants 00 learn how to conduct an exposure characterization I think you would see this

paper providing general guidance and concepts, but not details on "how to do it." This

is alright, but the paper would be of greater benefit if literature could be cited and a few

examples, including tables or figure, de~o~strating how actual exposure data are

compile.d, and analyzed such that they become useful for constructing the exposure

prof"J1e and are ultimately used to in conjunction with effects data to complete the risk

characterization. I would like to see a little bit of "hands on/how to" provided in the

paper. At a minimum, additional references on these subjects might b(, provided.

G-5. Relationship to EPA's Framework for ecological risk assessment

I think we have gone beyond the point of discussing whether or not the framework

approach works or not. I do not see any need for this type of discussion in this paper.

We cOUild discuss tnat issue, if deemed appropriate, at the workshop.

G-6. Examples

I mentioned a couple examples in responding to the previous questions.

Additional General Comments

(1) Exposure components are listed in the paper (page 4-10) as intensity, time, and

extent. Most of this discussion could be placed. in section 2 instead of the

introduction. The discussion in section 2 is limited to "extent"; what about

intensity and time?

(2) On page 4-20 (second paragraph) there is a good example of how professional

judgment is used to determine appropriate routes of exposure and how data might

be aggregated to abbreviate or facilitate the exposure characterization. One or

two more examples like this would be very instructional.

(3) I think there should be an expanded section on the need for uncertainty analysis

and methods for performing this analysis.

(4) There is no summary at the end of the paper. Should there be one?

. E-56
4.0 Characterization of Exposure

Specific Questions

4-1. Terminology selection relative to exposure characterization. Which terms are m 0 s t

appropriate?

(1) The EPA Framewor~ document indicates on page 5 that the term "exposure" will

be used instead of "characterization of stress.". The Framework document is

inconsistent. On pages 18 (Figure 3) and 19 stressor characterization is frequently used.

Within the same box on page 18 both terms are used. The Characterization of Exposure

paper written for this workshop also does not use the term "exposure" in lieu of "stressor

characterization. " This is simply to point out that the EPA. guidance given in the

Framework document is not followed. 1 see nothing ~appropriate. with "stressor·

characterization" or "characterization of stress", so I am not recommending a change.

It is obvious that there is not genefal agreement on the use of theses terms so I suggest

that the glossary of terms lists them all and indicate that they are often used

interchangeably.

(2) I reviewed the terms in the text box on the question page for the Characterization of

Exposure questions against those defInitions provided in the glossary at the end of the

Characterization of Exposure paper. The defmitions for the terms "Source, Agent, and

Stressor" are similar. The term "stress regime" is defmed quite differently in the two

places and I do not agree with either defmition! I think it is inappropriate to state that

it can be used in place of "characterization of exposure." A stress regime is a series of

exposures (co-occurrences ofstressors and organisms). The defmitions of "exposure and

disturbance" in the "text box" are good and I prefer them to those presented in the

glossary.

The key to successful use of terminology is consistency. Right now there is a need for

careful editing to insure consistency between papers and between the papers and the

Framework document.

4-2. What technical issues should be covered in more detail in the disturbance section (e.g.,

fragmentation or natural distlllrbance characterization)?

I thought the discussion on disturbances was a big improvement over previous summaries

on this topic.

4-3. How well do figures 2-6 reflect the structure used to assess exposure? What types of

exposures are not addressed?

Figures 2-6 are intended to be broad examples of the risk assessment process. As such

they provide a useful summary of information. The figures appear to summarize most

of the common exposure scenarios.

E-57
4-4. What modifications, if any, are required to improve the three primary exposure objectives

used in problem formulation listed on page 4-13?

The following minor modifications are recommended: (1) the "Agent and source title"

should be changed to "Stressor characterization" to be consistent with the Framework

Document; (2) the Assessment endpoint section on page 4-13 might be revised to reflect

that the assessment endpoint selection is primarily an effects related endeavor and that

from an exposure viewpoint the selection' of assessment endpoints' would be driven by

knowledge of the exposure regime and in particular, information about spatial, temporal

distribution that would influence the choice of assessment endpoints.

4-5. What modifications, if any, are required to improve the three primary exposure objectives

used in the analysis phase listed on page 4-22?

. .,

The only modification I would make at this time is to include a brief mention of the need

to quantify uncertainty associated with exposure (stressor) measurements.

4-6. Does the statement on page 4-26 that "the objective of most chemical analyses is to

estimate the concentration of chemicals in different media at equilibrium", need to be

modified?

(1) The object of most chemical analyses is to determine the concentration of the

analyte present in the matrix being analyzed! I phrased this in this manner to

point out it is easy to confuse terms. A single analyses is probably not what is

being discussed here.

(2) I don't believe that the objective of most exposure analyses are to determine

chemical concentrations in different media at equilibrium. The goal is to

d.etermine the exposure and/or exposure regime as it currently exists or existed

at some time in the past or future. It is true that equilibrium models are often

used to assist in assessing exposure, but the goal is not to estimate concentrations

of chemicals in different media at equilibrium.

4-7. Section 3.2 provides considerable detail on chemical fate and transport. Which areas,

if any, need to be deleted?

I am not sure any of the areas need to be deleted. I believe the sections on Advective

Transpolrt, TransferBetween Media, and Transformations could be shortened to one page

each, if one desired to do this.

4-8. Are the discussions on prospective and retrospective assessments (pages 4-9) and source

driven and effects driven assessments (page 4-18) appropriate and useful for consideration

of assessment types?

The comments on prospective and retrospective assessments are acceptalble, but they

probably don't belong in the introduction. The introduction is too long and needs to be

shortened. Relative to source driven and effects driven assessments the comments on

E-58
page 4-14 are sufficient. The additional comments on page 4-18 probably are not

needed.

4-9. What additions or deletions should be made to the knowledge gaps listed on page

4-491

(1) The issue of bioavailability was listed as a data gap. To be more specific,

information is critically needed on methods for estimating bioavailability for

compounds other than non-ionic organics and a few metals.

(2) A set of rules or guidelines could be developed to provide guidance on how to

prepare and present exposure profiles. This document provides guidance on how

to handle chemical analyses data and provide compilation, statistical, and

graphical presentation information, but very little on actual details.

(3) Information is need on how to calculate uncertainty associated with all portions

of the Exposure Analysis and Exposure ProfIle phases of risk assessment. .

E-59

Issue paper

on

CHARACTERIZATIOr,1OF EXPOSURE

Glenn W. Suter II, James W. Gillett, &SUe Norton

Reviewed by Lawrence A. Kapustka

review format

cross cutting issues 1

general impression of exposure chapter 2

specific technical issues 3

cross cutting issues

Ecological Risk Assessment (EcoRA) means a variety of things to practitioners, managers, and the

public. Clarifying what an EcoRA is and how one is developed is vitaily important. The in.tense

effort that led to the publication of the Framework for Ecological Risk Assessment (Framework) has

elevated the visibility of EcoRA in the regulated community and the general public. The task at

hand, as I see it, is to clarify ambiguous aspects of the Framework guidance, but equally important,

to provide sufficient detail on the process so that uniformly high quality EcoRAs can be produced.

Three concerns emerged in my review of the vari.ous chapters that deserve serious attention during

the workshop to guide subsequent revisions of the document.

1. focus -- The Framework correctly presents the importance of using an iterative process in

producing an EcoRA. However, in emphasizing this "spiral" from the broad encompassing

Scoping- and Screening-Tier assessment to the specific and tightly bound Final Tier, clarity was

not achieved. The elements of Problem Formulation, Analysis, and Risk Characterization were

presented with extensive cross-referencing to the multitude of interactive relationships. As a

consequence, the important technical definitions required to convert the guidelines into

operational steps are obscured. That tact of presenting an holistic view was acceptable for the

Framework; at this stage discrete, formal discussion of implementation are needed. My

impression of the issue papers (chapters) is that far too much discussion was devoted to the

"other topics."

recommendation: Present succinct discussions of exposure in the exposure chapter, effects in

the effects chapter, etc. If additional discussion of the holistic, interactive, and interative aspects

of an EcoRA is warranted, make that a stand-alone chapter.

E-61
Review: Ecological Risk Assessment Issue Paper - Characterization ofExposure

2. consiSfenc}{ -- Portions of the Framework were ambiguous, or perhaps unnecessary -- one

candidate for modification being the apparent redundancy in the Risk Characterization section.

Some of the confusion and redundancy might be reduced or eliminated by providing clear

descriptions of intent. Where appropriate, definitions should be refined. Nevertheless, invention

and redefinition of terms should be approached cautiously. Terminology and section headings

should carefully track those presented in the Framework.

Among the most troubling definitions offered in these issue papers is the term "agent." The

merits associated with this proposed terminology are few and minor. Weighed against the loss

of communication capability, this is a poor choice. There does not seem to be much difficulty

among technical persons in any portion of environmental science, management, or regulation

understanding what is meant by the separate terms entities of chemical, biological, or physical

realms. Biological systems, be they individuals or ecosystems, respond differently to each

realm. Serious analysis of exposure, response, effects, mitigation, monitoring, management, or

any other aspect of human interest in the environmental arena requires distinction among

biological, chemical, and physical variables. Grouping, and therefore losing the distinctive

information that might be conveyed if dealt with separately, can only lead to greater confusion

and less informed environmental action.

The apparent drive behind this particular terminology has been the concern that EcoRA has dealt

almost exclusively with chemicals and not adequately considered physical disturbance that lead

to diminished habitat for certain high profile species. Encumbering and diminishing the language

will not fix that problem.

recommendation: Special effort should be devoted to retaining consistent use of terms as they

are used in the technical fields.

The readability, and instructional value, of the issue papers would also be enhanced if they

tracked the specific topics.introduced in the Framework.

3. ecology & scientific rigor -- The foundation of EcoRA is anchored by two broad support

structures: ecology and toxicology. If either of these scientific constructs is misrepresented, the

value of the EcoRA will be diminished. The very nature of risk assessment, (Le., extrapolation

beyond data ranges) challenges the technical, scientific limits. Ecology as a discipline has the

distinction of operating without solid principles common to other natural sciences. In filling this

void, the temptation to use paradigms as principles has been seductive. Simplistic and

discredited explanations of effects responses, recovery, linear succession, restoration potential,

have crept into the overall presentation of the Framework and some of the issue papers.

recommendation: Take a hard look at the explicit and implicit ecological commentary in the

Framework with an eye on updating the ecological information so that it more accurately

captures the essence of ecology the science, rather than popular (non-science) ecology.

general impmssion of exposure chapter

The apparent instructions to the authors of all the issue papers were to cover their topic across the

three phases of the Framework guidance: Problem Formulation, Analysis, and Risk

Characterization. This approach has resulted in a series of issue papers that dilute and confuse the

discrete elements needed to produce a quality EcoRA.

I did not get a sense of a clear description or explanation of the essential features of exposure vis-avis an EcoRA; rather, there was a great deal of discussion that blended with effects, consequences,

and even expectations. The foundational relationships critical to conducting and interpreting EcoRA

are not expressly presented:

ecological planning and toxicology, Inc.

E-62
Review: EcologlcalRlsk Assessment Issue Paper- CharacterizaUon ofExposure

1. without exposure, there cannot be a response attributable to the "agent;"

2. with exposure, there may be a response;

3. a response may manifest into an effect;

4. an effect at one organizational level (e.g., individual, population etc.) may be realized at other

organizational levels.

The emphasis on "may" should not be diminished, given the great tendency to equate'the potential

for exposure with an actual ecological effect.

I wanted this issue paper on exposure to:

• discuss items 1 and 2,

• succinctly detail routes of exposure,

• present straightforWard descriptions of techniques to assess or document exposure,

• provide a smooth transition for the "effects" issue paper, and

• build the foundation for subsequent procedural documents akin to ASTM Standards.

Against these prejudices, this issue paper comes up short.

specific technical issues

1. Introduction

2nd sentence -- ...or othersystem must be in contact with or co-occur...

Co-pccurrence does not equate with exposure. Whereas co-occurrence may lead one to consider

the potential for exposure, it should not be construed as being more than a potential. The logical

extension of the statement as presented would be to accept a statistical correlation as confirmation

of a cause-effect relationship.

1.1. Scope

1st sentence -- scope...

In framing the scope as uptake or interaction with the "ecosystem or its component that constitute the

assessment endpoint ..." key features of exposure that are best evaluated in controlled laboratory

settings are exempt. Surrogate systems, whether biological or chemical, that are used as

measurement endpoints would not be included in this delineation of scope.

2nd sentence -- H ••• various human activities... H

It is inappropriate to restrict the description of disturbances to human activities. Whereas it may be

the role of a regulatory body to issue or deny permits, levy fines, etc., there is a broader purpose for

considering physical disturbances in an EcoRA. Non-anthropogenic disturbances should be factored

into the ecological analysis of risk. If the goal is to assess risk and analyze consequences of any

"agent" in an ecological context, it becomes imperative that one incorporates the key features of

ecological relevance whether anthropogenic or not.

ecological planning and toxicology, inc,

E-63
Review: Ecological Risk Assessment Issue Paper - Characterization ofExposure

3rdparagraph .- ••..separating biological agents..."

After reading the various segments of this issue paper, particularly the cumbersome diversions made

to accommodate simultaneous discussion of physical and chemical agents, it would seem preferable

to distinguish all three (biological. chemical, and physical) categories into separate chapters. At the

risk of sounding as if ASTM has panaceic solutions, the approach of having an umbrella documents

with annexes might be useful here. This would translate into a brief. cogent discussion of the critical.

cross-cutting features of exposure without regard for the type of "agent," supported with three

discrete discussions of biological, chemical, and physical "agents" respectively.

1.1.1. Sources and Agents

2nd paragraph.

There is an intriguing revelation of personal values in this chapter. Whereas a soy bean field has

many ecological distinctions from a True Prairie or Eastern Deciduous Forest ecosystem, it is hardly

equivalent to a parking lot. The tenor of this chapter is decidedly value laden and poorly grounded in

scientific terms. The entire discussion of systems elimination tenuous. No area on Earth is

permanently rendered sterile as implied in this paragraph.· Apparently the span of time is cast in

partial human life-span rather than ecologic or geologic reference. In doing so, the hypotheses

generated as the product of a risk assessment can easily be challenged.

1.1.2. Types ofExposures

Figure 2.

It is not obviolJs in Figure 2., that "Exposure" is to be represented in terms of the magnitude and

likelihood of convergence of the "agent" and the receptor. As presented, it becomes easy to assume

the Exposure-r~esponse relationship is unity and that exposure =effect. Consequently this figure

presents an imperfect conceptual relationship and does not promote development of an operational

strategy to conduct a valid EcoRA.

The flow through the six paragraphs illustrates the progressive merging of exposure and effects.

From an analytical perspective, it is critically important to determine exposure independent of

effects. The merging of indirect effects. secondary exposures, etc. should be handled in the Risk

Characterization phase. If the merger occurs from the outset, the depth of analysis possible will be

compromised.

2. Problem Formulation

3rd bullet "Eco:>ystem at Risk"

This should be stated as the "ecological resource at risk." Virtually all practitioners agree that EcoRA

do not occur at the Ecosystem Level. What should define :md EcoRA is the Ecological Setting or

Ecological Context. This permits evaluation of exposure and effects in terms of ecological

relationships and dynamics.

2.2.2. Extent Based on Effects

It is not clear how this section as written is relevant to the exposure chapter. The message can be

simplified to cover three points:

1. overt symptomology may help define exposure areas, (e.g. herbicide drift and dead plants);

2. mobile organisms may disperse chemicals leading to secondary exposures;

ecological planning and tOXicology, inc.

E-64
Review: Ecological Risk Assessment Issue Paper- Characterization ofExposure

3. slow acting effects may be manifested away from the exposure point.

2.4. Assessment Endpoints

p.4-19

2nd bullet -- turtles

Would and organism such as a heron or osprey be a better example?

4th & 5th bUllets

Change "...have the greatest exposure of ..." to "... have greater exposure potential of ..."

2.5. Causal pathways in Conceptual Models

1st paragraph

The ~ixth sentence is remarkable in being naive, fundamentally incorrect, and terrible guidance. For

assessment of phytotoxicity and in evaluating exposure pathways considerable distinction among

taxonomic groups or life-forms are possible.

3.1. Further Source and Agent Characterization

4th paragraph

Use full name for CFC.

5th paragraph

Adventitious exposure is a curious use of the term.

3.2.1.2. Transfers among media

1st paragraph.

It is interesting that special attention is given to methyl mercury as an example that may not be in

equilibrium. It would be much more instructive to provide an example of some ecological setting that

was in equilibrium. Are there any?

p. 4-28. last paragraph

The term "conservative" should be avoided in this context since it carries so many alternative

meanings.

3.2.2.1. Transformations

Biotic Reactions

Purge the anthropomorphic representation of microbes as naive. Better terms are available.

3.2.2.2. Interactions with Ecological Processes.

1st paragraph

ecological planning and toxicology, inc.

E-65
RevIew: EcologIcal RIsk Assessment Issue Paper- Characterization ofExposure

A closing sentonce should be added, explicitly stating that as the complexity and length of pathway

increases, the linkages become obscure, uncertainty increases, and plausible effects diminish.

3.3.1. Behavioral Attributes

p. 4-34 2nd paragraph - "These exposure-related behaviors are best considered as effects per se, ..."

Considering exposure equal to effects violates' the scientific basis of an EcoRA. It may be

convenient for some purposes, but it is wrong. One should not lose sight of the "life" that such

directives develop. This contributes to the tendency for deSk-top assessments (Le., not verified in

the field), to incorporate worst-case scenarios that assume 100% bioavailability and 100% exposure.

The result of such exercises is less ecological relevance. Don't assume perfect correlation between

exposure and E~ffects.

3.3.2. Routes ofContact

1stparagraph

Why assume equilibrium?

3rd paragraph.

Add explanatory information regarding the continuing controversy. Namely, the model is based on

information gathered from hydroponic experiments only and as such presents an atypical exposure

condition. Moreover, the model is not able to accommodate the pervasive influence of rhizosphere

organism on root morphology (e.g.• suppression of root hair development; the primary point of

uptake in a hydroponicly grown plant),' and root physiology that are extensively documented in plant

physiological ecology writings.

3.3.4.2.

1st and 2nd paragraphs

These paragraphs emphasize biomarkers as effects measures. It would be more appropriate here to

discuss the exposure aspects of biomarkers.

3.4. Implementeltion Issues

Clarify the separation: 1) the selection and use of models, 2) data acquisition. Analysis should be a

part of both.

3.4.1.1. Validation

Use "Verify" nClt "Validate" in title and in paragraph.

3.4.2.2. Statistical Analysis

It was not clear to me what the two paragraphs provide in regard to exposure assessment.

4.1. Direct Disturbances

1st paragraph

ecologIcal planning and toxicology. inc.

E-66
Review: t;cological Risk Assessment Issue Paper - Characterization ofExposure

There are few physical disturbances that are truly as complete and pervasive as implied in this

paragraph. Change to reflect the typical, intermediate condition experienced.

second paragraph -- ..... harmful and then quantifying the effective deletion .....

This presentation as noted earlier is artificially bounded. First, value-laden terms like harmful

present an inappropriate bias to the risk assessment process. Disturbance may be detrimental to

some processes and resources while being quite beneficial to others. The Clementsian implications

of this presentation is disturbing intellectually. It would also suffice to state the changes as

modifications. This would account for deletions, additions, and alterations of a partial nature.

4th paragraph

The examples and implications (that highways are somehow more permanent and destructive than

reservoirs) are not very sound. Many secondary road, a lot of railroad rights-of-way, and numerous

ghost-town areas have reverted to non-managed status or have been transferred to be managed as

ecological resource areas. I suspect that the such transitions occur more frequently and of greater

spatial extent than that occurring from reservoir silt-in.

5th paragraph

The purpose and meaning of this paragraph is not apparent.

.:

.... "

ecological planning and toxicology, inc.

E-67

REVIEW OF RISK ASSESSMENT FORUM ISSUE PAPER

NO. 7.4: CHARACTERIZATION OF EXPOSURE

by Frederic H. Wagner

The authors have done a lot of work on this chapter. The following comments,

based on three days' review, obviously do not come from the same amount of thought,

and background research, and so mayor may not be valid. But they are offered as food

for thought, and hopefully will be useful.

General Areas for Consideration

G -1

I am assuming that this entire document will become a procedural guide or manual

for people engaging in risk analysis. Hence I think it should provide the user an

understanding r:lot only of the conceptual matters treated in this chapter, but as well a

reasonably concrete sense ot'the assessment procedure including the sequence of aC?tual

steps taken. To a degree the sequencing of the topics and lFigures 1-8 do this, but I

think not concretely or completely enough. Hence I think one or more hypothetical (or

real, if appropriate ones are available) step-by-step examples should be included in the

treatment.

Let me show how the failure to provide this kind of concrete understanding and

abstract nature of the discussion raise questions in my mind. One turns on the distinction

between prospective and retrospective assessment (ct. Questions Relevant to Particular

Issue Papers 4-8). Both of these procedures are mentioned several times in the chapter,

and the distinction between them is touched on briefly on p. 4-9. But I think failure to

describe them more fully and exemplify them leaves the assessor unalerted a priori to the

E-69
2

very different operating procedures which the two imply.

My assumption is that prospective assessment must involve situations in which a

decision, policy, or action is being contemplated that will affect the environment. The

purpose of assessment is to predict that effect. This general perspective is stated or

implied a number of times in the chapter (1.1.3, 2.5, 3.2.2). The procedure is largely a

modelling one, and involves analyzing the magnitude and nature of the source and agent,

and of the system to be affected. The established or known parameter values of these

analyses are structured into a model which is then used to predict the effect(s) of the

agent on the impacted system.

Retrospective assessment, if I understand it correctly, is more empirical and a

posteriori. It must measure parameters of affected systems and compare them with

parameters of similar but unaffected systems to detect, and quantify the magnitude of,

effects. Thesta are then related to agents that have been identified and measured.

Establishing cause and effect might involve experimentation. This whole scenario is in

essence a resElarch project of some significant time period with associated personnel and

equipment. 1·13ven ask whether it fits the description of risk assessment.

It seems to me that "source-driven" ,and "effects-driven" assessments (again

Relevant Question 4-8) fit this same dichotomy, may be rough synonyms of prospective

and retrospective assessments. And don't they have the same operational implications?

The same questions arise with model validation (ct. 3.4.1.1). This involves selecting

key parameters of systems for which predictions are being made and mE~asuring these

periodically (monitoring) over time to determine whether or not predicted changes are

E-70
3

taking place. There is an implied time, personnel, and equipment need here that may not

be obvious to an assessor reading this Issue Paper. It needs to be spelled out before

he/she commits to this action and embarks on it.

G ·-3

, Except for the above matters, I find the terminology consistent and clear. The

glossary is helpful.

'G·6

See above comments re step-by-step scenarios.

Questions Relevant to Particular Issue Papers

, 4·1

I have commented above on terminology and generally feel that it is OK. But the

definitions in the text box are 'succinct, and the box, if included in the chapter text, would

be more convenient to refer to than paging back to the glossary.

. 4·2

I do think the discussion of disturbances'is brief. There is a whole literature that

deals with disturbance ecology. It explores such aspects as pulse vs. continuous

disturbance, varying impacts on functional groupings (species, guilds, trophic levels, etc.),

and on spatially different impacts. Perhaps not relevant for this chapter, but these

considerations lead naturally into the subject of restoration.

I know there are space constraints, but subject to this,' it might be worth including

brief, generic discussion on the forms of disturbance: meteorological/climatological (flood,

global warming), human mechanical (mining, agricultural, urbanization, logging, livestock

E-71
4

grazing). etc. Can an agen~ (e.g. an anthropogenic chemical) that eliminates a whole

species or combination of species become a disturbance thereby?

4·3

I have problems with Figures 1-7, and perhaps these are due to my entrainment

on conceptual diagrams for modelling. Maybe these figures are designed for a much

more general purpose. but even so I think they are ambiguous in places. So I'" make

this comment and it can be ignored if not relevant.

In my experience with these kinds of diagrams, each symbol represents an explicit

system entity. Boxes represent components of the system (chemical nutrients. biomass.

individuals. populations, etc.) and are measured as point-in-time state variables. Arrows

represent processes (metabolic, photosynthetic. natality, movement, decomposition) and

are measured .as rates. The constraints on the process rates are shown in varying forms.

often as bow ties on the arrows. Models are constructed from rate functions expressing

the process rates as functions of different values of the constraints, and predict changes

in the state variables. Validation consists of·measuring state variables over time to see

if they change according to prediction.

In our present context, Fig. 8 (p. 4-70) is constructed in roughly this form:

rectangles are state variables. processes are hexagons, and constraints are shown as

arrows from thl9 agents and disturbances on right impinging upon hexagonal processes

on the left. In general. I think agent and disturbances function as constraints on

processes (DO in respiration. toxicants on a variety of physiological processes. UV-B on

plankton mortality).

E-72
5

In Figures 1-7, the boxes variously contain state variables (zooplankton), processes

(zooplankton mortality), constraints (agents, pesticides), and functional relationships

(exposure-response curves). In some cases they contain combinations: state variables

and constraints (pesticides and birds), processes and constraints (UV-B and zooplankton

mortality). I'm not sure on where "risk of effect" fits our conceptual framework. Arrows

simply convey unspecified causal flow.

I suppose these diagrams are nothing more than starting points to begin

conceptualization of the problem confronting an assessor. But the one(s) representing

the final predictive model(s) that he/she uses will be very different. If Fig. 8 can serve

both purposes, can't a similar approach for Figs. 1-7?

4-4

Ae Agent and source. If source and agent are unknown, how can observed

effects be attril;>uted to, any agent, and to what end does the assessor define potential , ,

sources and agents? It seems too hypothetical for any policy action.

4-5

It seems to me that this Analysis Phase (Section 3) is treated pretty.thoroughly

here. But it strikes me that this phase needs to be carried out in close association with

Effects Characterization. It can't be known how complete the source characterization is

unless the affected components and processes of the impacted system are known.

Same with pathway analysis: A simple, exhaustive cataloging of all fate and transport

processes could be an abstract effort. Attention needs to be focused on those fate and

transport processes that lead an agent to th~ affected components and processes of the

E-73
6

Impacted systE~m. Similarly, the interactions with ecological processes cannot be usefully , • ' J

detailed until the impacted system and its processes are known. Can "effective"

concentration IJr dose be known except for specific system components and processes?

4-6

Why only at equilibrium? Many agents are increasing over timE~. Restoration

aspires to reduce them.

.E-74
Effects Characterization

Workgroup Leader:

General Reviewer:

General Reviewer:

Dr. Jeffrey M. Giddings

Springborne Laboratories

Dr. Nelson Beyer

National Biological Survey

Dr. Wayne G. Landis

Western Washington University

E-75

Risk Assessment Forum

Ecological Risk Assessment Issue Paper Review

Issue Paper on Effects Characterization

Review comments by Jeffrey Giddings

The following are notes made as I read through the issue paper three times. They are in

order as they appear in the issue paper, not organized in terms of the review questions we

were asked to address. I did not have time to read all of the other issue papers, but I did look

at the papers on Conceptual Model Development and Characterization of Exposure to

address some of the cross-cutting issues.

Unfortunately, Federal Express will come for this package in less than an hour, and there is

not time for me to summarize my thoughts on each of the review topics. My general reaction

to this issue paper is that it is comprehensive, touches on most of the important points, and

is reasonably well balanced. In some sections, as I have noted below, there is too much

emphasis on what the Introduction calls "greatly improved theoretical and empirical

foundations" for addressing large-scale ecosystem-level effects, at the expense of more

practical, conventional approaches for addressing individual and population level effects.

While I think the ecosystem approach is important and opens up many interesting questions

for research, I think the current need is for clear, pragmatic guidance to those in EPA and

elsewhere who are trying to develop scientifically sound risk assessment programs-even if

that entails reliance on more pedestrian concepts and more ordinary sources of information. I

don't think the ecosystem considerations should be left out of the document, but I think they

should be brought into balance:

This comment is related to the issue of current capabilities VB. future needs. Perhaps the

recent spate of books and manuals on ecological risk assessment are already filling the need

for coverage of current capabilities, but I would like to see this issue paper prOVide a better

perspective on tools and approaches that are actually in use, and less emphasis on exciting

new concepts and areas for future exploration.

My apologies to the other reviewers and to the authors for leaving this review in its current

state of disorganization, but the time allocated wasn't enough to include reflection and

summarizing. I look forward to discussing these issues at the workshop.

Review Topic

G-1

E (Editorial)

Notes and Comments

Goal of chapter: "explore principles and data bases" used for

characterizing ecological effects. Principles I understand; I'm not so sure

what is meant by data bases.

Introduction has a couple of puzzling phrases: "level of resolution desired

E-77
Risk Assessmerllt Forum Issue Paper on Effects Characterization: Peer Review

from other ecological manipulations" (lines 2-3) and "quantify, in so far as

that may be possible" (second paragraph, third line). These phrases don't

seem to fit the sentences.

C-3

G·3

5·1

E

5-1

The introduction notes that biological stressors will be discussed in

another chapter, not much in this one.

Section 2.1.1.-Definition of direct and indirect effects. "Direct effects are

those that can be related causally to exposure of the stressor." Not a

clear definition-indirect effects are also related causally to stressor.

"Indirect effects occur as a result of the changes induced ... by a stressor

acting on the physical or chemical environment or on habitat quality,

rather than as a direct response to the stressor." Again, not a very clear

distinction here (unless the reader already understands the distinction).

Implies that all effects of physical disturbance (dredging, etc.) would be

indirect (since all involve stressor acting on the physical environment).

"Habitat quality" apparently includes food supply and other ecological

aspects-otherwise, this definition of indirect effects doesn't seem to

include effects caused by reduction in food supply, for example.

The best way to convey the concept of direct and indirect effects is by

example. The examples need to clearly illustrate the distinction. In the

case of the aerial insecticide in Canadian prairies, be explicit: The

insectide causes direct toxic effects on macroinvertebrates; it doesn't

cause direct effects on ducklings, but the reduction in macroinvertebrate

food supply causes indirect effects on recruitment of ducklings.

I wonder: how important, for the purpose of risk assessment, is the

distinction between direct and indirect effects anyway? (I don't mean,

how important are indirect effects-but is it important that we categorize

them as indirect?)

Section 2.1.4-Levels of ecological organization. (Section title says

"biological organization" but this should be changed.) The classical

, diagram of space-time scales (Fig. 1) is fine. But I like the comment (top

of page 5-12): "the distinctions between levels of organization are not as

real as they seem."

Second to last sentence of long paragraph on p. 5-12: for clarity, change

"longer than that for'~ to "longer than the scale for". '

Section 2.2-lndividuals and populations. Quibble, p. 5-14: I wouldn't call

the LC50 an expression of population effect. The "population" of reference

in an LC50 is simply the test population, not as ecological population (with

E-78
Risk Assessment Forum Issue Paper on Effects Characterization: Peer Review

associated emergent properties). The Le50 is a concentration that has

50% chance of killing an individual-eoncept seen clearly in the nearly

synonymous term, TLm.

5-1

5-1

E

G-3

G-3

5-2

G-5

G-5

G-3

Section 2.2, p. 5-14, final sentence on the relevance of field studies. A'

very important point, seems to conflict with OPP's "new paradigm".

Section 2.2, general comment: Not very much attention paid here to

population-level assessments (life table analysis, etc.). It comes out in

later sections, but a brief discllssion here would be appropriate.

Section 2.3-Ecosystem structure. Second paragraph, first sentence:

Meaning is very unclear. "...effects on ecosystems, rather than on the

specific structure of the .ecosystem itself...". What is the distinction?

"...although, obViously, this is ecologically important as well. ..". What

does "this" refer to?

Section 2.3, p. 5-15, second line from top of page: "Reductions in

numbers, biomass, and taxonomic and trophic diversity indicate a shortterm disruption in equilibrium conditions." Equilibrium conditions may not

exist on the short-term; reductions may be due to natural fluctuations (this

is the big problem of distinguishing stressor effects from natural variability,

alreay referred to)..

Section 2.4~Ecosystem function. Section is too concise. Need an

overview of "ecosystem functions" (with examples) in this section on

concepts and terminology. This is especially important in light of the

emphasis on ecosystem properties later in the chapter.

Section 2.5-Pulsing and stability. Discussion is forward-looking, well

beyond current capabilities. "Our understanding of these risks ... is still

too incomplete to prescribe a standard methodology."

Presumably, all of Section 2 relates to Problem Formulation; Section 3

relates to Analysis; and,Sections 4 through 7 relate to Risk

Characterization. These correspondences could be made more explicit in

the issue paper. So Section 2 should include a discussion of how these

concepts are used in developing a conceptual model (ties in with chapter

on Conceptual Model-revisit this after reading that issue paper).

Section 3.1-Endpoints. To correspond with Framework, this discussion

would belong with Problem Formulation (Section 2).

Definition of "effect" in section 3.2 (first paragraph) might be better placed

in Section 2.

E-79
Risk Assessmenf: Forum Issue Paper on Effects Characterization: Peer Review

5-1

G-2

E

M (Miscellaneous)

G-2

E

C-3

5-1, G-4

Table 2 is extremely useful. Gives a great capsulated view of the different

effect measurements at different levels of ecological organization.

Section 3.2.1-Effects on individuals. Page 5-21, last line, mentions

"growth of individuals is measured in toxicity tests for ... some algae". Not

that I know of-all algal tests measure population growth (cell density,

biomass).

I am not familiar with the review by Vouk and Sheehan (1983), but from

the reference to it in section 3.2.1 I infer that it is mostly about higher

animals. There should be some mention here, for the sake of

completeness, about the very common aquatic invertebrate reproduction

tests (daphnids, mysids, sea urchins).

Page 5-23, third line of first full paragraph begins "Several reviews of full

life-cycle and other partial life-cycle tests ..."; I think this should be

"reviews of early life-stage and other partial life-cycle tests ...".

Last paragraph on p. 5-23 is too compact for me to penetrate its meaning.

Exactly what is a global index? Why is it preferred for expressing toxicity

test results for individuals? How would weight of young per female be

calculated-total weight of all offspring at birth? Would this index be

substantially more useful than total number of offspring per female (as

commonly measured in chronic tests with invertebrates)? The paragraph

is puzzling; not illuminating.

Section 3.2.2-Populations. There could be some mention here (or

reference to further discussion in section 5) of modeling approaches to

interpret mortality and reproduction data (e.g., typical toxicity test results)

in terms of life tables and population dynamics.

Section 3.2.2-last paragraph, second sentence: I think "generic

composition" should be changed to "genetic composition".

Section 3.2.2, last paragraph addresses population genetics. This is a

critical issue for release of genetically engineered organisms. More .

discussion is warranted.

Section 3.2, reviewing the types of effects data, includes 2.5 pages on

individuals, 1 page on populations, and 4 pages on ecosystem structure

and function. To the extent that the number of pages reflects the depth of

discussion (and I think it does, pretty much), this indicates a heavy

emphasis on the ecosystem level. However, available data and methods

for interpretation exist mainly at the individual and population level. The

first sentence of section 3.2.2 notes that the population is the focus of

E-80
Risk Assessment Forum Issue Paper on Effects Characterization: Peer Review

most ecological assessments, and I agree. This section does get into

some interesting and forward-looking science, but it lacks practical impact.

The discussion of diversity (Section 3.2.3) plays down the importance of

this widely used parameter without explaining or illustrating its limitations.

It may be true that air pollution effects on plants aren't reflected in

diversity indices, but there are certainly situations (e.g., effects of metals

or pesticides on aquatic invertebrate communities) where diversity is a

sensitive and informative measure of effect.

On the other side of the coin, section 3.2.4 (Ecosystem Structure and

Function) includes a long paragraph about effects on resistance to

disease and insect attack. Some of the argument involves long chains of

indirect effects-changes in photosynthesis or nitrogen availability

affecting C:N ratios of primary metabolites, thus affecting production of

secondary metabolites that confer disease resistance, thus increasing the

incidence of disease, thus causing extensive damage to forests. The

paragraph concludes by acknowledging that this is a "new dimension of

risk assessment for which research is only beginning." I don't necessarily

deny the potential importance of this phenomenon in nature, but I don't

believe it will be a consideration in developing risk assessment guidelines

for years to come. (Also, this topic might fit more appropriately in the

section on effects on individuals.)

Contrast this paragraph with last one in section 3.2.4, on the Index of

Biological Integrity. IBI is not considered useful in its present form

because it can't be applied broadly across very different types of

ecosystems. The specific shortcomings of IBI are not explained.

In short, Section 3.2 leans heavily towards novel, largely unexplored,

systems level measures of effects and away from the measures that are

the basis for most ecological risk assessments conducted today. I'm

afraid that many users of this document will sense a certain ecological

snobbery and anti-faddism, and will not find this section very helpful in

designing assessments for everyday use.

G-2

C-5

Section 3.3.1-Data Quality. There is much more to quality assurance

than the use of controls-proper documentation, maintenance and

calibration of instruments and equipment, avoidance of bias in sampling

and measurement (mentioned in section 3.3.3), prevention of crosscontamination, accuracy of calculations, training of personnel, and so on.

I'll try to bring a few appropriate reference citations to the workshop.

Section 3.3.3-Representative Data. Mention is made of the difficulty in

relating toxicity test data to environmental exposure, because the toxicity

E-81
Risk Assessment Forum Issue Paper on Effects Characterization: Peer Review

tests don't use relevant exposure methods. This is a very important point.

In my experience with risk assessment of pesticides, for which real-world

exposure patterns are much more complex than those used in acute and

chronic toxicity tests, the connection between measurement endpoints

and assessment endpoints is extremely uncertain; predictive assessments

for regulatory purposes are forced to incorporate worst-case assumptions

and large "safety factors". Since laboratory toxicity tests are likely to

remain the most important source of data on ecological effects, a serious

effort is needed to design more relevant exposure methods.

G-1,5-1

G-3, C-5

Section 4-Analysis of Stressor Responses. The objective of this section

isn't clear. Is it to present examples of quantified effects? That's a terribly

broad objective, and not clearly differentiated from the previous section.

Certainly section 4.1.1 (Direct Effects of Chemical Stressors)

doesn't-can't-begin to cover the enormous amount of information that

has been generated from laboratory and field studies. The treatment in

this section (4.1.1) is unbalanced and disorganized: a paragraph citing

several studies of effects on reproductive effects, a paragraph indicating

that studies have linked chemical contamination to mortality, a paragraph

mentioning that chemicals can affect population abundance, and a

paragraph with three examples of effects on disease resistance.

Section 4.1.2-lndirect Effects of Chemical Stressors. The authors caution

that "the concept of what is direct and what is indirect needs to be treated

carefully" and I would concur. Some of the examples given in this section,

especially the changes in soil chemistry brought about by acid

precipitation, could be considered to be aspects of stressor

characterization, not effects characterization. Is AI toxicity in plants a

direct effect of one stressor (AI), or an indirect effect of another stressor

(H+)?

The two examples of indirect effects caused by reductions in food supply

and by reductions in nesting habitat and cover are classic illustrations of

what! consider to be indirect effects. Maybe it's b~caw~e I'm an ecologist,

not a chemist. In a simple situation, stressor.A causes an impact on

ecological receptor Y. If the change in receptor Y in turn causes an

impact on receptor Z, I consider the effect onZ to be an indirect effect of

stressor A. If stressor A causes a chemical change, it may create a new

stressor B, which can cause an impact on receptor Y. I wouldn't consider

this an indirect effect of A on y, I'd consider it a direct effect of B on Y.

This issue is discussed in Chapter 4 (Section 1.1.2), using similar

examples; the two chapters are not inconsistent, and an effort to

harmonize the paradigm and the terminology would be fruitful.

E-82
Risk Assessment Forum Issue Paper on Effects Characterization: Peer Review

G-6

5-1

E

C-5

5-1

E

C-4

C-5

Section 4.4-Multiple Stressors: Terrestrial Case Study. This is a

fascinating example of indirect effects, but not a clear example of mUltiple

stressors. If I understand it correctly, lower soil pH reduced the rate of

litter processing by invertebrates, resulting in immobilization of Ca,

reduction in soil Ca:AI, and impairment of tree growth. What are the

. multiple stressors? Perhaps this is another case where the distinction

between stressors and receptors is not clear.

The introduction to Section 5 (especially pages 5-45 and 5-46) reflects a

good balance between individual, population, and ecosystem level

assessment models.

At the top of page 5-46, "Leslie Matrix" is misspelled.

Section 5.1.2 and 5.1.3 (which could be conveniently combined into a

single section) address time-concentration-response functions. It should

be noted that time, in this analysis, refers to duration of continuous

exposure to a constant concentration. Since concentrations are often not

constant (see my comment above), more complex models (such as that of

Mancini 1983 cited on page 5-45) are needed to predict effects.

Sections 5.2, 5.3 and 5.4 on system level modeling are well done. They

properly begin with a caveat about the need for further development of

ecosystem models, and give some good examples.

Section 5.5, first paragraph, 7th line from top: refers to "frequency of

some disease". From the context, I assume this can be generalized to

any type of ecological effect.

Section 5.5-Evaluation of Causality-provides some much needed

perspective. The nine factors reflecting causality are useful for

retrospective assessments. The final paragraph addressing extrapolation

to other conditions and ecosystems is applicable to predictive

assessments. And the comment about the need for mUltiple lines of

evidence is important for both kinds of assessments.

Section 6.2-Extrapolation from Laboratory to Field. The summary of

limitations of lab tests is useful and highly relevant (it's a critical issue for

pesticide registration under the "new paradigm", for example). The second

paragraph notes that extrapolation models haven't been developed to

address the influence of factors that affect availability of chemicals. I see

this as an exposure issue, not a stressor-response issue; models do exist

for predicting, for example, dissolved chemical concentrations in situations

with high suspended sediment loads, allowing the assessment to deal

with biological availability.

E-83
Risk Assessment Forum Issue Paper on Effects Characterization: Peer Review

The fourth paragraph (page 5-56) addresses time-varying exposure-an

issue I've commented on above. The first sentence seems to be missing

a word: I think "continuous constant" should be inserted before the final

word, "concentrations".

G-2,5-2

M

There are several good reviews, and some recent workshop reports,

addressing the use of microcosms and mesocosms. I'll provide some

references at the workshop.

I agree with the general conclusion that field studies have shown that

aquatic communities are less sensitive in many cases than would have

been expected from laboratory data. I think this is partly a matter of

bioavailability, partly of time-varying exposure, and partly a reflection of

the inherent resiliency of complex natural communities. The strategy of

protecting 95% of all species, for example, may be unnecessarily

conservative-even when a larger fraction of the community is affected,

the overall structure and function of the system can remain intact.

Section 6.4-Extrapolations across Spatial and Temporal Scales. The first

paragraph is actually about extrapolation among ecosystem types. not

across spatial scales, but it's a very useful discussion all the same. The

second paragraph addresses extrapolation to long time frames. and

suggests that the difficulty stems from lack of understanding about aging

of long-lived species. I think a more important problem in long-term

extrapolation is the cumulative uncertainty over time-the same

phenomenon that makes it hard to predict next week's weather.

E-84
Nelson Beyer Patuxent Environmental Science Center

July 27, 1994

Review of "Effects Characterization"

General comments

Ecological risk assessments are an applied part of the field of

ecotoxicology, and the chapter on "Effects Characterization" will be most

useful if it provides guidance on how best to carry out a risk assessment

given the kinds of data likely to be available and our current level of

understanding of ecosystems. Rather than describe what an ideal risk

assessment would include, it would be better to describe what is currently

achievable and explain to the reader how to go about it. Probably most

ecotoxicologists would agree that although we know a lot about ecosystems, we

are a long way from understanding how they function. It may be many years

before we do have reliable·models of ecosystems, but in the mean time we must

do the best we can. Some of the concepts discussed in the chapter would be

impractical to include in a risk assessment, and I think that using a more

pragmatic approach would make the chapter stronger.

Some risk assessments are national efforts involving teams of scientists

working together for years. Modelling global warming would be an example. I

assume this chapter is also meant for the more common situation, the one in

which regulators must decide what to do about a ten-acre lot on which unknown

quantities of chemicals were dumped in an area that is already polluted,

borders a marsh, and has a few species of wildlife. What should be sampled

and measured to produce a modest risk assessment that the scientific community

would consider acceptable? I kept these questions in mind as I read the

chapter.

E-85
Much of the literature cited in the chapters discusses concepts.that are

in the process of development. Models were mentioned whose investigators

suggest that they can link changes in populations to communities, or provide

other links that would be useful in risk assessment. The reader wants'

guidance, wants to know more than just that someone is working on a.model,but

whether the model is workable, if it has been tested, and if it is acceptable

to the scientific community.

Probab'ly the most useful improvement to the chapter 'would be to inc,lude

more methods from risk assessments that successfully handle some of the tough

questions. For example, Table 1 suggests "significant decrease in tree canopy

bird populat'ions" as an assessment endpoint and a "dietary LD fifty for

Japanese quail egg hatch and fledgling" as,a measurement endpoint. How do we

get from one to the other? This question must have been addressed in many

risk assessments.

The discussion needs-to be a bit more down-to-earth. For example, on

page 5-58 the authors state that ItMultivariate statistical tests could be used

to estimate the probability that the ecosystems of interest belong to the same,

state space as the ecosystems used to develop the exposure-response model. lt ,

Before getting into statistical tests, I would want to know the criteria that

should be used to decide whether two ecosystems are the same~ I fear that a

dozen different biologists would have ·a dozen different opinions. In parts of

the chapter, the discussion of statistics and models has gotten ahead of the

more basic question of what we should measure and why.

The paper barely discusses biochemical indicators, pathology, and the

use of chemical residues in tissues to estimate toxicity. Whether the authors

agree or disagree with these approaches, they should give the reader some,

gUidance, since thesemeasur~ments have been basic to environmental

E-86
toxicology. Consider the way in which biologists have evaluated OOT tn·

raptors, for example. From field studies we know that some populations of

raptors have declined and that the declines are related to eggshell thinning.

From laboratory studies we know what residues in eggs are associated with

eggshell thinning. Performing a population study, particularly of raptors, is

generally well beyond the means of a local investigator. However, a biologist

can put together a solid argument simply by collecting eggs from a site,

analyzing them for DDT, and interpreting the results in view of previous

studies. Should residue analyses of eggs be 'recommended as measurement

endpoints for organochlorines? And what should be recommended about

pathology? If the chapter had been written by a pathologist, le'sions might

have been emphasized. What kind of guidance can be'given on indicators, such

as ALAO for evaluating lead poisoning? A great deal of work is now being

conducted on cytochromes P-450 and related enzymes. In section 3.4. phenol

glycosides seem to be recommended. Are some physiological indicators

legitimate measurement endpoints for risk assessments and what criteria are

us~d to decide? I know this question is controversial, but I think ~he

chapter should provide some guidance.

The discussions on the complexity of ecosystems could be shortened by

referring the reader to the literature. Most biologists are aware~, for

example, that ecosystems can be viewed on different time and spatial scales.

Rather than be reminded that ecotoxicology is complex, they want specific

recommendations on how to deal with the complexity.

It seems that effects on populations or higher levels of organization .

are especially important according to this chapter. 'I fear that readers have

different ideas of what constitutes a population. For example, if half the

robins on a campus are killed by a pesticide, has the population been "

E-87
affected? If readers have different ideas of what is meant by a population

they are going to perform quite different risk assessments. If we take the

position that some mortality is significant and other mortality is not

significant, where do we draw the line?

Predicting effects on ecosystems from effects on individuals is critical

to this chapter. Several times the reader is referred to the "aggregating up

paradigm" by Cai. The citation is to an abstract and poster presentation.

Since this work seems to be so pivotal the authors should explain the process

thoroughly.

Specifics

2.1, 2.1.1 The explanation is longer than necessary. If a stressor affects

organisms or the abiotic environment, which in turn affects an organism being

considered, the effect is called indirect. Toxicity from ingesting a lead

shot would be an example of a direct effect, stunted growth from lack of prey

killed by acid rain would be an indirect effect.

2.1.4 Del ete

2.4 Unclear - What does "regulatory ~gents and rates magnify the linkage ... "

mean? What is recommended here?

2.5 "Transients outside the range of resilience for the system can be

induced, creating a new, potentially degraded and irreversible equilibrium.

The induction of undesirable alternate stable states, and possibly technically

chaotic responses, is probable under some circumstances." What does this

jargon mean? The section is too abstract for the audience. When I read about

a transition to a new equilibrium I first want to know equilibrium of what.

What kinds of measurements are being discussed?

3.2.1 Unlike some of the other sections, this section is written in a style

E-88
that assumes too little of the reader, who already knows that successful

reproduction 'i~ essential to populations and that shortening life spans can

affect populations. Also note that lC fifty studies can be chronic, although

they are less common than acute tests.

3.2.3 It may not be necessary here to introduce so much terminology - top-down

control, cascading, multispecies population ecology, and species-sensitive

ecosystem function research, since they are not mentioned later. I see why

descriptions of ecosystem and community structures may be similar, but I would

suggest avoiding calling them equivalent concepts.

3.2.4 (The first paragraph is unclear and I may have misinterpreted it.) I

would be hesitant to insist that fine-scale changes must be related to

productivity, since productivity may at times be unresponsive to drastic

changes in the biota. Some stressorscause an increase in productivity.

Should changes in nutrient cycling be a measurement endpoint? Should an

element have to be shown to be limiting before a change in cycling be

considered biologically significant?

3.3.4. This section is weak. Could it be replaced with a brief comment, to

the effect that when statistical results are not significant, investigators

should report the power of the test. (ref.)?,

4.3.1. The explanation of the joint action model is unclear. Why should the

expression equal I?

5.5 The concept of uncertainty should be reserved for statistical variability

arising from data. If the investigator cannot determine a causal relation

between an effect and a stressor, then a risk assessment should not be

performed.

6.1, 6.2, 6.3 Give some recommendations.

7.1 Figure 5 seems to be an important model for the chapter. Unfortunately it

E-89
shows axes of parameters without explaining which parameters are recommended

and which would not be appropriate. It would be more helpful to include an

example with real data from a risk assessment.

f_ I ,

E~O
RiSk Assessment Review-August 4, 1994-Draft

7.5 Effects Characteri%3tion-Review by Wayne G. Landis

General Comments

I apologize forthe obviously rapid turnaround and lack of polish that accompanies this

review. I hope that I am able to improve the section On effects and provide some additional

flterature. Attached are copIes of some recent papers that may also aide the wrtters.

Although summa~ngthe potential for effects and means to measure them is a daunting

task. this section misses much ofthe literature that has a direct bearing on this aspect of

environmental toxIcology. Much of the review could have been published in the mld·1980·s after

reviewing the citation nSf, yet there has been an incredible amount of literature published since

the tum Of the decade. 'The review also lacks a critical edge. Often statements are offered without

references, I take it that these are the often unsubstantiated opinions of the authors. I reaJrze that

these statements are harsh, but there are also parts thaI I really do enjoy, such as the lack of

confirmation in the use of the ISr, although a reference is important here. This is a crttical

document and needS to be herd to rigorous standards. In some instances some of the

conclusions of some of the references, such as Matthews 19B2, are not accurately represented

and have been greatly supplemented by more recent publications by the same author (see

Matthews and Matthews 1990. Matthews et al 1991a, 1991b, Landis et al1993a, 1993b,

Matthews et aI, in press and Landis et aI1994). There is an extensive literature that deals with the

structure of ecological systems, much of it far removed from Odum and Caims. I am also surprised

that many of the classics of population biology and community structure are not included. nor a

discussion of chaos and complexity theory as described by.May (May and Oster 1978), Hassell et

al (1991). orthe important ~orkS of Kauffman (Kauffman and Johnsen 1991, Kauffman 1993). In

the last ten years there has been an intense discussion of the meaning and existence of stability

within ecological systems and this is missed in the diScussion.. Also stnl<ing is the absence of the

work of DaVid TIlman (1982, 1988, 11Iman and Wielden 1991) that clearly describes the

importance of resource ratios in predicting the structure of ecological systems and this work has

also been applied to systems undergoing tOXicant stressors (Landis 1986). The discussion found

within thi~ section relies too much on only a few papel'$ and points of view, and the ecological

literature is underrepresented.

Also missing are the multivariate approaches to detennining the status and vector

direction of ecological systems as published by Kersting (1988) and Johnson (1988). Recently,

other methods have been published and used (Matthews and Hearne 1990, Matthews et al

'991a, 1991b. etc.) that detail a very powerfUl approach to measurements of effects at the system

E-91
Risk Assessment Review-August 4, 1994-Draft

level. There are also other researchers attempting to elucidate the patterns found in ecological

systems that are beyond the simplistic index snapshot approach.

Specific Comments

2.1.1. Direct and indirect Effeets.-A review of Wiegart and J. Kozlowski (1984) would

useful here. I use perhaps simpler definitions in order to distinguish these types of effects:

Dire.;t Effects-those effects mediated directly by the molecular interaction of the toxicant

and the receptor site.

Indirect Effects-those effects not mediated directly by the molecular interaction of the

toxiC'.ant and the receptor site.

Physical and chemical stressors also tend to have sites of action within the organism so these

definitions also are useful in those cases. O.,e of the points that is generally not made is that

direct and indirect effects happen at the same time. even though the outcome of the indirect

effects may be harderto determine. Indirect effects also tend to be long lasting and can persist

long aftertho toxicant or other stressor has been left behind. Also misleading is the example

used on page 5-9 where it is implied that indirect effects move up the trophic levels, Ofcourse

this is not thn case. Indirect effects move more like a npple with the pathways determined by the

connections between that population and the rest of the populations within that species

assemblage..Indirect effects can also be thought of at the organismal level. Selection for

resistance to- a particulartoxicant also causes an increase in the frequency of genes linked to this

resistance tr.9.it. These genes alterthe gene pool of the population and may alterto outcome to a

subsequent toxicant or other stressor event. Two examples come readily to mind. First, the

receptorfor TeDD is found in vertebrates, except apparently jawless fish, and is apparently an

important mE~diator of earty development. 11,e divergence of vertebrates from otherforms of

animal life was at least 500 million BP and the jawed from jawless fish about 350 million bp. The

occurrence ()f such a receptor unique to jawed vertebrates is likely due to a long ago stressor

event that ~Iused a population bottleneck, and the indirect outcome was sensitivity to a toxicant

that did not E~xist until far into the future. The second example is the mitochondrial DNA

sequences Elmong Homo sapiens. These haplotypes apparently reflect population bottlenecks

of various populations and apparently are region specific.

In orderto distinguish between direct and indirect effects and to demonstrate how

immediate and important the outcomes are, I use Rgure 1 presented below. The figure is based

E-92
Risk Assessment Review-August 4, 1994-Draft

upon the factors important in descnbing how organisms and populations use resources and

respond to competitive interactions as described by TIlman (1982).

Direct and Indirect Effects on an Individual

R~on

s~ ~empora1 V, 7ll~

BioticComponems of

Resource Base

Historical

Impacts and

Alterations

Toxicant

Figure 1. DIrect and Indirect Effects using the Factors of Resource Competition Modeling.

I have found that this figure is useful and ties these types of effects into a mechanistic theory of

species interactions. In general it would be betterto include a more complete list of types of

direct and indirect effects rather than the few examples presented in this section.

2.1.2. Distinguishing Ecological Effects of Chemical and Physical Stressors.-In this

section there seems to be a tack of review of a variety of research attempting to descnbe

population cycles, effects of disturbances. and an attachment to recovery. Only one reference is

cited, yet there is contemporary research addressing the problems of environmental data analysis

and interpretation, In fact, the concluding statement of this section is incorrect. Hypothesis can

E-93
Rrsk Assessment Review-August 4. 1994-Draft

be tested abOutfluctuating systems, the data do not fluctuate. There are theoretical descriptions

of these f(uct!..1atiOns and methods of examining the data.

While there are cyclic and stochastic changes in populations. there are now several

documented instances of chaotic dynarnics. Chaotic dynamics are deterministic andthere is a

great deal of c:lassic research investigating their occurrence in ecological systems (May and Oster

1978. Hassen et a11991. Hastings et a1199S. Schaffer, 1985, Schaffer and Kat 1985). There are

also investigations that detail the long term variations in natural systems.

A recant investigation into variation with a set of natural systems has been conducted by.

Katz et aI. K::ltz etaL (1987) examined the spatial and temporal Variability in zooplankl:on dala from

a series offlVe rakes in North America. Much of the analysiS was based on limnological data

collected by 8rige and Juday from 1926 to 1942. Copepods and cladocera. except 805m/na,

exhibited larger variabifrty between lakes than between years in the same lake. SOme taxa

showed consistent patterns among the stUdy lakes. They concluded that the controlling factors

forthese taxa operated uniformly in each of the study sites. However, in regards to the depth of

maximal abundance for calanoid copepods and Bosmina. the data obtained from one lake had

little predictive power for application to other lakes.

Perhaps my biggest cflfficufty with this section and also the issue paper 7.7, Ecological .

Recovery, is that it is assumed that a disturbance-recovery dynamiC is in fact a true representation

of ecological systems. This has its root again in the Clementian notion of an ideal system for a

particular environment. Yet ecology is moving towards a non-equilibrium v~e~int. Hutchinson

(1961) invokeCi non-equilibrium conditions to explain the paradox of the plankton. Strong (1992)

has prepared an excellent overview of non.equiJibrium themes in contemporaJY ecology and

should be summariZed. I have problems with unproved and perhaps unprovable assumptions. If

as Yodzis (1988) states. ittakes over 2 turnover cycles through the longest track of the food web

to rearJZe a tMoretical equilibria, in many ecological systems this exceeds greatly the historical.

record. Given the incidence of catastrophic events such as fires, floods, disease and evolutionary

events on a much shortertime scale the opportunity of reaching an equilibrium must rare.

The return of a system to its pre.existing state. structurally. metabOlically and dynamically,

is a classical c1efinition of recovery. The property that confe~ upon a system the ability to recover

is stability. It has often been assumed the stability is a property of persistent ecological systems. It

has even been suggested that the examinatiOI' of stability and the measurements of resilience

and recovery are the most appropriate attributes to be studied in multispecies toxicity tests

E-94
Risk ASSessment Review-August 4, 1994-Draft

(deNoyeUes 1993). Even in situations where an equilibrium does not occur it is assumed that

given more time that replicate systems will converge toward an equilibrium condition (Rosenzweig

and Buikema 1994). As comforting as an assumption of ecological stabnity may be, there is an

increasing amount of data that indicate that stable systems may be the exception.

In regard to populations. Connell and Sousa (1983) examined a great deal of the

literature on population dynamics and found stabirrty as return to original conditions extremely

ra~. Andrews (1991) in a study oftropicaJ lizards found that the population dynamics are

unstable. Hypothesized causes are the rapid population turnover and the complexity of a food

web.' Kauffrnan in a series of publications (1991.1993) suggests that ecologieal systems need to

operate on the edge between stabirrty and deterministic chaos. Stable and the community can

not adapt and a cascading collapse can occur. Chaotic and wild events happen, including

extinction.

Ourresearch and the analysis of a variety of data has led us to conclude that equilibria a~

illusions (landis et aI1993b). There are many biotic and abiotic factors that govem the

composition of an ecosystem alter a stress event; substrate type, distance from colonjzing

sources, genetic variability of the resident population are but a few. Since each of the initial

cond'rtions are likely to be diffe~ntfrom those that lead to the original system, it is unlikely that the

sUbsequent system will be idemicaL Similarity, however, does not mean the same. In fact,

similarity at the structural level may lead to an iUusion of recovery.

Fil'st the apparent recovery or movement of the dosed systems towards the reference

case may be an artifact of our measurement systems that allow the n-dimensional data to be

represented in a two or one dimensional system. In an n-dimensional senSe, the systems may be

moving in opposite directions and simply pass by similar coordinates during certain time intervals.

Positions may be similar, but the n-dimensional vectors describing the movements of the systems

can be very different.

The apparent recoveries and divergences may also be artifacts of our attempt to choose

the best means of collapsing and representing n-dimensional data into a two or three dimensional

representation. In orderto represent such data, it is necessary to project n-dimensional data into

three orfewer dimensions. As infOnTIation is lost when the shadow of a cube is projected upon a

two dimensional screen, a similar loss of information can occur in our attempt to represent ndimensional data The possible musion of recovery based on this type of projection is

diagramatically represented in Figure 2. In Figure 2a the dosed and the reference systems appear

E-95
Risk Assessment Review-August 4, 1994·Draft

to converge, J. e. recovery has occurred. However, this may be an illusion created by the

perspective ctlosen to describe and measure the system. Rgure 2b is the same system but

viewed fmm Rhe "top". When a new point of view is taken, divergence of the systems oec:urs

throughout tl"18 observed time period. As the various groups separate, the divergenolJ may be

seen as a separate event_ In fact, this separation is a continuation of the dynamics initiated eamer

upon one aspect of the community. Eventually, the illusion of recovery may simply be the

divergence of the reprlCal:es within each treatment group becoming large enough, with enough

inherent varfcrtion, so that even the multivariate analysis can not distinguish treatment group

similarities. Not every cfivergence from the control treatment may have a proximate causal effect.

Divergence then Recovery

~"ll&.. /'

Reference

E~ystem

.......

A

B

Time

Side View

Divergenco then Recovery

Reference

Elsystem

----.....

'ons

Top View

Figure 2. The lIIusion of Recovery. Recovery depends upon the point of view. Since ecological

systems are highly dimensional, it is likely that selecting a particular point of view will highly bias

the interpretation of the dynamics.

E-96
Risk Assessment Review-August 4, 1994-Draft

Finally. there are data that demonstrate that the information about the prior state of an

ecological system exists and even a very basic lever. Experimental evidence forthe importance of"

historical events has been found in other experimental systems. Drake (1991) assembled in

varying orders the components of a relatively simple microcosms system. The structure of the

system was highly sensitive to the order of the introductions. While stochastic explanations may

seem to describe snapshOts of ecological systems. knOWing the historical dynamics elucidates

mechanisms of species interaction and provides deterministic descriptiOns of the system. In one

experiment, two systems that had different histories but were indistinguishable using the

methods available, produced different outcomes upon an invasion by Cydops. Recently (Drake

et aJ 1993), these findings were further confirmed by using a set of microcosms set up as islands

with an invasion (inoculation) scheme. HiStorical events, as in the timing, invasion success and

- persistence of the organisms lead to the development of systems in different regions of

ecosystem space.

Conditioning of the ecological system following a stressor event has also been

demonstrated in the work of Blank and colleagues (Blank and Wangberg 1988, Blank et a11988,

Molander and Blank 1992). Pollution induced community tolerance (PICT) Is a phenomena in

which populations of a toxicant stressed community evolve resistant organisms or are replaced by

pollution tolerant invaders. This process has been demonstrated for several toxicants among a

marine periphyton assemblage. The development of tolerance certainly depends upon historical

factors, are there resistance genes in the population, rate of immigration by resistant organisms,

and rates of sexual and asexual reproduction among many othen>. Not only would the

development of resistance likely alterthe outcome of a subsequent event, linked resistance

genes or genes unrelated to toxicant decontamination would have the potential to affect

responses to other types of stressors.

A record of historical events can ~!so be maintained in the population genetics of resident

popurations. Murdoch and Hebert (1994) examined the mitochondrial DNA (mtDNA) of

populations of bullheads found in the Great Lakes. Through the use of restriction enzymes that

cut the DNA molecule in very specific sites, 42 distinct mtDNA haplotypes were identified. In

pairwiSe comparisons of contaminated versus relatively clean sites, the population from the

contaminated site had lower genetic diversity. Ail sites contained large populations of brown

bullheads. No single mtDNA haplotype dominated the contaminated sites, implying that the

mtDNA was selectively neutral. Murdoch and Hebert conclude that the reduction in diversity is

due to a population bottleneck reducing the popUlation to a few individuals and eliminating ma.ny

of the rntDNA haplotypes from the population. Although the population levels are similar, the

E-97
Risk Assessment Review-August 4. 1994-Draft

genetics of fthe populatiOns are significantly different reflecting the historical bottleneck due to

contaminatkm.

section 2.1.3. The COncept of Threshold and Section 22. Unking Stressor's to

IndMduaIs .Elnd Populations etc.

These sections really address many of the same issues and consolidation should be

considered. The concept of threshold is directly tied to the abifity to detect effects.

If ec:ological systems were organisms then perhaps some sort of threshold before a

stressor has an effect may be a vafid concept However, once the stressor can affect an organism

to a point so that the survivorship of its genome is altered. then evolution kicks in. If

envitonmenRal toxicology isto be consistent with biology as a whole then consistency with

evolutionary biology must be maintained. Cairns (1992) states as the authors do that the

threshold co,ncept is objected to because it i$ seen as too permissive and therefore wrong is not

a scientific 131rgument. Neither is the concept of a threshold once an evolutionary.event takes

place. Cairns does argue that effects are hidden due to the inherent variability of ecological

systems. TItis argument simply means that if it can not be measured using am·ent techniques

then the effE!Ct does not exist. Well. it is now possible to probe these types of dynamics using a

variety of methods_ Pimm and Redfearn (1988) examined the variety of population densities

using spectral analysis. They actually discovered that the long term trend is cflVergence, not

convergencl~towards an equilibrium state. Other methods are being used to explore effects in

data with vaLiation.

Lucassen and Leeuwangh (1994) did use canonical correspondence analysis to find a

treatment related effect upon species composition. A major advantage of this approach is the

attempt to examine the structure of the system as a whole and not piecer:neaL The difficulties with

using correspondence analysis in this context are the low abundance of some organisms and the

Jack of replication. Although the authors were tentative, the do suggest wit is thought that

statistical methods that visuartZe long-term processes at community structure level might be

helpful in describing the threat oftoxic chemicals on ecoSystems.- The second exception is linear > ,

structural relations (USERAL) (Johnson, Huggins and deNoyelles 1994). LISERAL is an attempt

to test whether a hypothesized ecosystem structure fits the data. produces interaction

coefficients between the components of the model and produces stability measurements. This

method is multivariate and does attempt to analyze the system as an entity. USERAL does have

the bias. in'that it hypothesiZes a knowledge of 'the structure of the ecological community. and its

interpretation presupposes ecological stability-There are several other promising techniques.

E-98
Risk A$S~ssm~nt R~view-August4, 1994·Draft

Mu!tivari$te methods have proved promising as a method of incorporating all of the

dimensions Of an ecosystem. One of the first methods used in toxicity testing was the calculation

of ecosystem strain developed by Kersting (1984, 1985, 1988) for a relatively simple (three

species) microcosm·..Trt!s method has the advantage of using aU ofthe measured parameters of

an ecosystem to look fortreatment-reJated differences. At about the $ame time, Johnson (1988a,

1988b) developed a multivariate algorithm using the n-dimen$ional coordJoates of a multivariate

data set and the distances between these coordinates as a measure of divergence between

treatment groups. Both of these methods have the advantage of examining the ecosYstem as a

whole ratherthan by single variables. and can track such processes ':is succession. recovery and

the deviation of a system due to an anthropogenic input.

My colleagues and I currently uses a variety of techniques including.metric and nonmetric

clustering to detect effects within microcosm and field data. In orderto cOmpare dynamics we are

experimenting with several new techniques but currently use projections that al'e ca"~ space ,

time worms. These methods have now proven useful in detecting patterns.in biomarkers in field

experiments and the conditioning of microcosms. As described elsewhere in this.review, typing

of mitochondrial DNA and other markers will.n1uminate even basic evolutionary e~ent~.

As we as scientists get better at detecting effects the threshold question will eventually.

disappear as being one of the myths of env!tonmental science. Apparent threshold isperhaps a

better t~rm if you must inSist. However, there will come a point when decisions will!Jave to ~.

made on acceptable impacts, as we get better- at measuring evolutionary events.

Apparent thresholds do not mean no effect- I can illustrate this point simply In Rgure 3, I. , . " ., .'., '

have use a simple difference equation to model a species with non-overlappil1g generations. 111e

initial start points are different by 2 points in 10,000. The populations oscj1late in a stable fashion , .. .',,'

around the canying capacity but a slightly out of sink.. .WIthoutyears of d~ differentiating

between this two circumstances will be diffiCI.Ilt and the initial difference w!lI.prObablyfallbelow an

Appar-ent Threshold. However, upon the application of a new stressor, the lowering of the

carrying capacity by 20 percent. one population become extinct and the other starts to oscillate , "~, ,A'

around the new carrying capacity. Since ecological systelilS are historical smarr events can have

large consequences. Extinctions of isolated populations is probably a common event.

Metapopulation dynamics often rescues such sites but the probability of rescue depends on the

. geometry of the patches and the dynamics within a patch. Wu {1991} illustrates these poir:ns in

dramatic fashion.

E-99
Risk Assessment Review-August 4, 1994-Draft

14000

12000

Switch of K from 10.000 to 8,000

Effects of Starting eof\ditions on Population

Pynamics

1GOOO T------:....---'i<'Ic;::;;;;d1~;;;;_n==:__Q~..., K lowered 8.000 9999

: n--- 10001

···

•

•

c 10000-1----~iIl

o

;::

8000

g.

:. 6000

4000

2000

20 30 40 50 so

Tirne

10

o+---or----,r----r---.---.-....---'t

o

FlQUre 3. Different Outcomes from Slightly cfrfferent initial conditions. R is equal "to 2.0, K is initially

10.000 and that is lowered at time 50 to a,ooo. One population becomes extinct as the other

cycles around 8,000.

Section 5. Ecological Response Analysis: 1he Role of Various Types of Models-Before

attempting te) incorporate models into the discussion, an in~epth review of Oreskes et al (1994)

should be m;ade. Essentially they state that models can not be validated or verified, merely

confirmed. Although useful. models are best used to ask further questions, not a representations

ot reality.

Next:. the basic types of models are not those stated on page 5-44. In the AI literature, a

contrast is made between similarity·basedsystems and explanation-basedsystems (Lebowitz.

1990). A tracfrtional physical model. for example, which wiD incorporate each relationship in the

real world into a relationship between objects in the computer program. is an explanation-based

system. It attempts to reconstruct the cause and effect evolution of the real-wond system within

the computer system and it will account for the observed data by explaining its causes. Statistical

and strictly mechanistic models are both explanation based models. Similarity-based Systems

stand in conl:rastto these systems. Similarity-based systems attempt to analyze the data on its

own terms, without preconceptions about explanations. Generally similarity-based systems

attempt to discover abstractions or generalizations that can reduce the complexity of the data.

E-l00
Risk Assessment Review-August 4, 1994-Draft

Similarity-based systems excel in discovering patterns and relationships within the data that were

unknown to human experts, and have in fact been used with great success to diagnose soybean

diseases, olScover new classes of stars, and design aircraft subsystems (Michalski and Chilausky.

1980: Cheeseman et aI., 1988; Domeshek et aI., 1994). The periodic table is an example of a

similarity based model. Nonmetric c{usteJing and association analysis is anotherexampJe of a

similarity based models used in the analysis of ecological datasets (Matthews et al1990, 1991, in

press and lm1dis et a11993a, 1993b, in press). The third type of model is a physical model. In

the case of ecological toxicology an example would be the numerous multispecies toxicity tests,

although even single species toxicity tests fit the bill. The models described in sections 5.1 to 5_5

all fit the explanation-based modeling scheme.

I also noticed that experimental methods of modeling the response ot ecological systems

to stressors was barely mentioned although it has an extensive literature. As an example of the

extensive literature. a recent review by Gearing [1989] listed eleven freshwater artificial stream

methods, 22 laboratory freshwater microcosms ranging from .1 to 8,400 liters, 18 outdoor

freshwater microcosms ranging from 8 to 18,000,000 liters, and even larger numbers of marine

systems. The methods range from completely synthetic systems to those that rely upon

colonization by natural inocula. In addition to toxicological studies they have also been used to

investigate the assembly of communities and the rules of landscape ecology (Drake 1991. Drake

et aI1993). Microcosms Nave also been used to develop and test hypotheses such as Pollution

Induced Community Tolerance (Mol/andar and Blank 1992). Unlike explanation based models,

these systems anow the discovery and testing of hypothesis that deal with complex biological

systems. The major difficulty with these systems has been the problem of extrapolation. The

same problem applies to all moc;fels as Oreskes et al (1994) have illuminated•. Experimental

physical models certainly have an important role to play.

Likewise, field studies as models are not addressed yet they serve the same role as multispecies

toxicity tests. The variability of real world may preclude the same types of repeatability that is

expected from laboratory tests- However, the real world is historical and nota repeatable entity.

There are rules but they are fundamentally different from those of simple single species systems.

Perhaps we should learn to play by the rules of the raal world instead of forcing pur views to the

point of abandoning the system of interest.

The rote of modeling is best illustrated in section 5.2.2 in the work of Vanni. A model was

developed for a specific case, predictions made, and the results tested against a historical

dataset- Questions as to the specificity of the model and Calibration always exist. However, the

E-10l
Risk Assessment Review-August 4, 1994-Draft

role of model!; in genemting testable hypothesis is certainly valid and is seen as tile primary role

modeling by Oreskes et al (1994).

References and Selected Readings

Andrews, R. M. 1991.The population stability of a tropical lizard. EcoTogy72:1204--1217.

Clements, F. e. 1916. Plant succession: An analysis of the development of vegetation. Garnegie Inst.

Washington PUb. No. 242-

Drak9,J. A. 1991. Community-assembly mechanics aIld the structure of all experimental species

ensemble. Amer.. Nar.137:1-26.

Drake,J. A.. T. E.Rum, G.J. Wrtternan, T. Voskuil, A. M. Hoffman. C. Creson, D. A. Kenny, G. R. Huxel, C.

S. Larue. and J. R. Duncan. 1993. The construction and assembly of an ecologlcallandseape. J. Animal

Ecology. 62:117-130.

Good. I.J. 198:2. An index of separateness of clusters and a permutation test for its slgniflC3l1c:e. J.

Statist. Comp. SimuL 15, 81-84.

GoodmaIl, LA. aIld W.H. Kruskal. 1954. Measures of assooiation for cross classifications. Joumaf of

the American Statistical A5S()ciation 49:732.

Hutchinson, G. e. 1961. The paradox of the platlkton. Amer. Nat. 95:137-143.

Hassell, M.P.H. Comins. N. and May, RM. 1991. Spatial structure and chaos in insect population

dynamics. Nat,'re 353:255-258.

Hastings, A.. C. L Hom. S. Ellner, P. Turchin. H. C. Godfray. , 993. Chaos in ecology: Is mother nature a

:strange attractm? Annu. Rev. £COT. Sysr. 24:1~.

Jain. A.K and RC. Dubes. 1gas. Algorithms for Clustering Data Prentice Hall. Englewood Cliffs. N.J.

Jorgensen. S. W. 1990. Ecosystem theory, ecological buffer capacity. uncertainty and complexity.

£col09icaJ Mod9/ing.52:125-133.

Kauffman, S.A. and S.D. Johnsen. 1991_ CoQvolution to the edge of chaos; coupled fitness landscapes.

poised states and coevolutfonary avalanches. J. thoor. Bioi. 149:467·505.

Kauffman. SA 1993. The Origins ofOrder. Se/foOrganization andSelection in Evolution. Oxford

University Press Inc., New York, New York. pp 709

Johnson, A.R. 1988. Evaluating ecosystem response to toxicant stress: a state space approach. In

Aquatic Toxicology andHazard Assessment: 10th VoTume. ASTM 5TP 971 (Adams. W.J•• Chapman, G.A.

and Landis, W.G., eds) American Society for Testing and Materials. Philadelphia,.pp. 275-285.

Johnson, A.R. 1988. Diagnostic variables as predictors of ecological risk.. Environmental Management 12.

515-523.

Katz. T.K.. Frost, T.M. and Magnuson. J.J. 19137. Inferences from spatial and tempotal variability in

ecosystems: Long-term zooplankton data from lakes. Amer. Nat, 129, 830-848.

Kersting, K. 1988. NormarlZed ecosystem strain in micro-ecosystems using different sets of state

variables. Vern'.lntemat. Verein. Limnol.23. 1641-1646.

Kauffman, S.A. and S.D. Johnsen. 1991. Coevolution to the edge of chaos; coupled fitness latldscapes,

poised states and coevolutionary avalanches. J. theor. Bio/. 149:467-505.

Kauffman, SA 1993. The Origins ofOrdll!; S9lf-Drganization and Selection in EvoTution. Oxford

University Press Inc., New York, New York.

E-102
Risk Assessment Review-August 4, 1994-Draft

landis. W. G. 1986. Resource competition modeling of the impacts of xenobiotics on biological

communities. Aquatic Toxicologyand Environmental Fate; Ninth Volume ASTM STP 921. J. M. Poston and

R Purdy Eds., American Society for Testing and Materials. Philadelphia, pp 55-72.

Landis, W.G.• R.A. Matthews, A.J. Markiewicz, NA Shough and G.B- Matthews. 1993a. Multivariata

Analyses of the Impacts of the Turbine Fuel Jet-A Using a MicrocosmToxicity Test. J. Environ. Sci. Vol

2:113-130.

Landis, W.G., RA Matthews, A.J. Markiewicz and G.B. Matthews. 1995b. Multivariate Analysis ofthe

Impacts of the Turbine Fuel JP-4 in a Microcosm Toxicity Test with Implications for the Evaluation of

Ecosystem Dynamics and Risk AssGssmen'L Ecotoxicolagy 2:271-300.

landis, W.o., R.A. Matthews and G.B. Matthews. 1993d. Complexity, imwersibility and multispedes

systems. SETAe News 13:5 pp 8-9.

landis, W.G., G.B. Matthews, R.A. Matthews and A. Sergeant. In press 1994. Application of multivariate

techniques to endpoint determination, selection and evaluation in ecological risk assessment. Environ.

Toxicol Chem.

Lebowitz, M. 1990. The uttlity of similarity-based learning in a world needing eXplana%ion. In Kodratoff. Y.

and Michalski. R. S.. editors. Machine Learning, An Artifrciallntelligence Approach, Volume til, pages 399-

422. Morgan Kaufmann, Los Altos. CarJfomia. .

lorenz, E N. 1993. The EsssnC8 of Chaos. University of Washington Press, Seattle.

Matthews, G. and J. Hearne. 1991. Clustering without a metric. IEEE Transactions on Pattern Analysis

and Machine Intelligence. 13(2):175-184.

Matthews, G. and A. Matthews. 1990a A model for describing community change. In Pesticides in

Natural Systems: How Can Their Effects Be Monitored? Proceedings of the Conference, Environmental

Research laboratorylORD. Corvallis Oregon. EPA 910919-91-011.

Matthews, RA, G.B. Matthews and B. Hachmoller. 1990b. Ordination of benthic macroinvertebrates along

a longitudinal stream gradient. In Annual Conference, North Amerieafl BenthoTogical Society, Blacksburg,

Virginia

Matthews. G.B., RA Matthews and B. Hachmoller. 1991a. Mathematical analysis oftemporal and spatial

trends in the benthic maaoinvertebrate communities of a small stream. Canadian Journal ofFisheries and

Aquatic Sciences. 48,2184-2190.

Matthews, R.A.. G.B. Matthews and W.J. Ehinger. 1991b. Classification and ordination of IimnologieaJ

data: a comparison of analytical tools. Ecological Modeling. 53, 167-187.

May, A.M. and Oster, G.F. 1978. Bifurcations and dynamical complexity in simple eeological models. Amer.

Nat. 110:573-599.

Michalski. R.S. and R.L Chilausky. 1980. Learning by being told and learning from examples: an

experimental comparison of the two methods of knowledge acquisition in the context of developing an

expert system for soybean diseases. Policy Analysis and Information Systems, 4.

Molander. S. and H. Blank. (1992). Detection of pollution-induced eommunity tolerance (PICT) in marine

periphyton communities established underdiuron exposure. Aquatic Toxicology22:129-144.

Murdock. M. H. and P. D. N. Herbert. 1994. Mitochondrial DNA diverstiy of brown bullhead from

contaminated and relatively pristine sites in the Great lakes. EnViron. Toxico!. Chem.13:1281-1289.

Nicolis, G. and I. Prigogine. 1989. Exploring Complexity. W.H. Freeman and Co. New York..

Noreen. E.W. 1989. Computer Intensive Methods for Testing Hypotheses. New York, N.Y., WileyInrerscience.

Oreskes, N•• K. Shrader-Frechette, and K. Belitz. 1994. Verification, validation and confirmation of

numerical models in the earth sciences. ScienCE! 2~: 641~646

E-I03
RiSk Assessment Review-August 4, 1994-Draft

Pimm, S. L and A. Redfearn. 1988. The variability of population densities. Nature 334:G13·G14.

Schaffer, W. M. 1985. Can nonlinear dynamics elucidate mechanisms in ecology and epidemiology? 11M

JournalofMatfJ9matics App!ilKlin M«fICine andBiology. 2:22.1-252. . .

Sehaffsr, W. M. and M. Kot. 1985. Do strange attraetors govem ecologieaJ systems? Bioscience 35: 342-

350.

Strong, D. R. 1992. Non-equilibrium themes for ecological theory: Implications for fungal communities. In G.

C. canon 2nd D. T. WlCkJow Eds, The Fungal COmmunity. MarcaJ Dekkar, Inc. New York, NewYork.pp 1-15.

Suter, G. W.IL 1993. A critique of ecosystem health concepts and indexes. EnViron. Toxico/. Chern.

12:1533-1539.

liIman, O. and O. Weldin. 1991. Oscillations and chaos in the dynamics of a perennialgras5. Natur"

353:653-655.

illman, O. 19SU. Plant Strategies and the Dynamics and Structure of Plant Communities. Princeton

University Pross, Prineoton.. pp 350.

Tilman. D. 198!~. Chapter 6, Discussion: Population dynamics and species interac:tions. In Roughgarden,

May and Levin Eds., Perspectives in Ecological Theory. Princeton University Press, Princeton, New

JQl'SOy, pp 89-100.

Wiegart. R. G•.and J. Kozlowski. 1984. Indirect causality in ecosystems. Am. Nat 124: 293-298.

Wu,J. and J.L Vankat 1991- A sys~m dynamics model of island biogeography. Bullstin ofMathematical

Bio!ogy53:911-94O.

Yodzis, p.19Sn. The indeterminacy of ecological interactions as perceifed through perturbation

expgrimants. Ecology G9:S08·515.

E-I04
Biological Stressors

Workgroup Leader:

General Reviewer:

General Reviewer:

Dr. James A. Drake

.University of Tennessee

Dr. Richard Orr

U.S. Dept. of Agriculture

Dr. James H. Thorp, '"

University of Louisville

E-I05

Pre-Meeting ConIlEms - Biological S1ressors - James A Drake

1.0 General Areas

G-1: Clarity of purpose and scope

One conceptual question. Is the issue paper restricted to invading species

whose source is outside the continental US (e.g, pigs in Hawaii, or movements within

the country)? Should we be concerned about a species native to the Pacific

Northwest which invades the Southeastern United States, when Atlantic and Pacific

salmon are transported cross-continent, or when Rainbow trout precipitate a decline in

native Brook trout?

I very much appreciate the author's fairness in presenting both viewpoints over

what effect invaders have. Clearly, many species pose no risk whatsoever. At the

same time the occasional successful invader proves to be a spectacular problem.

This is good balance, but I do have one probabilistic concern. The author's mention

two "camps" of thought, one purporting that "... the average introduced species will be

very unlikely to create an environmental stress." V\A1i1e this is true it also seems to me

that we are not concerned with the average species, rather the impact of the outlier.

Hence, I think that this is a case where statistics are not terribly insightful and perhaps

misleading. Detrimental invasions will occur. That they occur with a frequency of

0.0001, does little to ease my concerns when that 0.0001 could represent many

species per year given the o!1slaught of invaders we are experiencing. Even though

this is a Poisson skewed distribution, that the tail is present (at significant cost) caLJses

me concem.

This introduction serves the intended purpose. The author's might consider

citing a few of the recent invasion papers.

G-2: Completeness of coverage

Overall there seems to be a disproportionate emphasis placed on the

introduction of genetically modified organisms. \M1ile this is clearly a valid area of

concern, and I like these comments for personal reasons, is this too much? I agree

that GEO's should be treated like any other introduced species. Along these lines we

all realize that plasmids may be unstable, leaking elements into the environment raises

an important caveat. The authors state that tn'lf such "lateral transfer" occurs, the

same probabilities of survival, multiplication, dispersal, and harmful effects must be

applied to the organism receiving the genetic information'lII. This can be read to mean

that the expression of the plasmid in the recipient will not differ from the effect seen in

the source (e.g., your words "... must be applied"). I aSsume you mean we must treat

such a hybrid organism in the same fashion, or to reassess, not the same exact waythere could be very significant differences.

E-I07
I wonder if it is worth adding a section describing emergent properties, their

relationship tC) the corrmunity at hand, and what happens when an invasion occurs.

This would fit well with indirect effects material.

The last thing which could be included, would be an example of a biological

stressor risk c:lssessment (e.g., Richard Orr's Chilean Log Assessment). This could

even be a figure.

G-3: Clarity and consistency of temlinology

I am uncomfortable with the "Frame\NOrk for Ecological Risk Assessment"

definition of the community. This is more than just a definition problem, because our

conception of the system, what ever it is, colors our interpretation of how the system

functions. I'm sure this will be a point of argument among workshop participants and a

discussion would be most helpful. 11,is is vitally important because, a functional

definition is critical to all the issue papers, and may improve success of the program

when it is implemented. The definition provided in the Framework is:

"COII11JLIlity-An assemblage of populations of different species within a

specified location in space and time".

Given this definition many different species ensembles could be accorded community

levels status whether or not those ensembles even possess community levels

properties. So conceiVed, it clearly possible to arrive at entirely incompatible

assessments on the same system and using the same variables. fts presently defi~ed,

it \NOuld be easy to show that an assemblage of Chironomids-the "corrmunity", is

actually enhanced by a toxicant (via. competitive release ...).

G4: Current capabilities vs. future needs

I feel this area is problematic with respect to invaders. fts the author's rightly

point out invasion success is a function of the invader and the system being invaded.

V\A1i1e we havE~ made considerable strides in understanding the conmunity, it remains

an elusive entity. Hence, current capabilities are less than adequate for much more

than plausible hunches. It would seem to me that a detailed analysis of several

assessments VJhich approached community-level issues, might be useful in pointing to

improvements in the implementation of an assessment.

G-5: Relationship to EPA's "Framework for Ecological Risk ftssessment"

See section G-3 corrment 1. I do have an additional comment about a

concept defined in the EPA document. "Stressor" is stated to "...induce an adverse

response". V\hat of those stressors which have some positive effect by one or more

measures, an effect which could induce a negative effect far removed from the scale

of analyses?

E-I08
G-6: Examples

These are all very solid examples. Perhaps a graphic which categorizes

invaders via generic effects (in some systematic fashion) might be useful for the

manager/risk assessor. For example, one could list a few invaders which (a) induce

changes in nutrient cycles, (b) hydrologic pathways (e.g., Vitousek), (c) cause a

decline in biodiversity, etc.

2.0 Questioos relevant to particular issue papers (issues raised by VERSAR and

EPA)

2.1 See G-2 above. At the same time this is a critical area because at least

with microbes we do have some post-release control, and a fighting chance. Such

control is absent elsewhere.

2.2 I agree largely with the position of the author's. Our ability to make

predictions is exceedingly limited, but not as hopeless as one would think at first

glance. For example, USDA's risk assessment on the import of Chilean logs to the

US shovvs that when we have a source and target a constructive and useful

assessment can be conducted. Richard Orr could conment on this further.

Non-specific invasions, on the other hand, present additional problems. Section

6-2 of "Review Topics" suggests that despite this fact we need to conduct risk

assessments anYWaY. Without salient information such an assessment seems to me

like a bit of science and a bit'on magic. I do not wish to be overly critical here, but, vve

have limited abilities with respect to understanding conmunities and their structure in

real time. It is no simple task to understand differentials in corrmunity vulnerability to

invasion and species-specific invasion.success. Now consider the added complexities

which arise when one embraces conmunities in both time and space-as the dynamic

entities they are (e.g., metaconmunities, succession and assembly dynamics)! I

believe the best course of action may be to focus on transport vectors, assuming that

the systems are vulnerable. This is the case with current legislation forcing

intercontinental ships to purge freshwater ballast before entering the Great Lakes.

3.0 Cross-cutting issues

There are endless issues which run throughout most of the issue papers which

cross-cut with the biological stressor paper. I'll need help here because I have had a

hard time coming up with a way to sunmarize all this complexity.

Cross-cutting issues I see in most papers include at least the following:

(1) The nature of the system

(2) The process of characterizing the stressor

(3) System response to the stressor

E-109
(4) Directing the system to a specific endpoint, or at least away from it's

current state. This does bring up the issue of endpoint, because I don't

believe we really ever have endpoints. Perhaps relatively persistent

transitional states-given our scale of observation..

4.0 Adcitional calillems

I thinl< we need to keep in mind that we are often dealing with spatially

extended systems. We can envision situations where a stressor will be large enough

to span more than one conmunity types, as well as disjunctions in ecosystem

processes such as the cycling of an important nutrient.

E-110
DATE

TO

FROM

28-July-1994

David P. ,Bottimore

VERSAR Inc.'

6850 Versar Center

P.O. Box 1549

Springfield, Virginia 22151

Richard L. Orr X 0

USDA APHIS PPD

6505 Belcrest Rd. RID. 810

Hyattsville, MD 20782

SUBJECT: EPA's Risk Assessment Forum's Ecological Risk Assessment

Workshop -- Comments on the Biological Stressors Paper

I appreciate the opportunity to review the Biological Stressors

paper. I found it easy to read, thorough in its scientific

coverage, and sound in its ecological assumptions.

The Biological Stressors paper, along with OTA's 1993 extensive

pUblication on Harmful Non-Indigenous Species in the United States,

and a number of other pertinent scientific papers on nonindigenous

species provides EPA with the present state-of-the-art overview of

the problems involved with biological stressors. This is a

necessary step in order to proceed with development of a Biological

Stressor Risk Paradigm.

I believe that, with a few minor changes, the scientific content of

the Biological Stressors paper need not be changed. James Drake's

research will be helpful in clarifying some of the issues in the

paper; but of course Dr. Drake will himself address these points.

The weakness in the Biological stressors paper in not in the

science, but in the next step -- how do we use this information to

make decisions about biological stressors.

The ending statement in the paper "At present a Delphic process

remains the most reasonable starting point, once the uncertainties

involved are clearly stated" is not all that helpful since EPA

already knew (long before the paper) that scientific input and

correct identification of areas of uncertainty were important.

One of the main functions of a good risk assessment is to take

scientific information and put it into a format that can be

understood and used by a pOlicy maker in making a decision. The

Biological Stressors paper does not do this.

Government policy makers are still going to have to make decisions

about biological organisms no matter how little is known about them

or no matter how complex and chaotic the environment/organism

interaction is. The Biological Stressors paper is full of what can

go wrong in evaluating biological stressors but does little to help

scientists organize what information they do have into a usable

E-lll
format for the policy maker that:

• communicates what is known about a specific biological

stressor and how it interacts with the new environment;

• communicates the degree of uncertainty about the biological

stressor and how it interacts with the environment;

• is transparent as to why a specific policy decision about

a specific biological stressor is necessary;

• is defensible;

• is open to evaluation, and

• is flexible enough to incorporate new data or information.

The overall impression I received from the Biological stressors

paper was that the state of scientific knowledge about biological

stressors and environmental interactions is so limited that any

attempt to base a prediction on what will happen to a specific

nonindigenc>Us introduction is impossible, or at best a wild guess.

I only partly agree with this philosophy.

I will grant that the ability of an introduced species to establish

involves a mixture of the characteristics of the organism and the

environment in which it is being introduced. The level of

complexity between the organism and the new environment is such

that the failure or success of a species in a new environment will

be based on minute idiosyncrasies of that interaction. I agree

that at the present' time one cannot predict in advance what

idiosyncral5y is going to trigger a successful or unsuccessful establishml~nt•

I also believe that ecological dynamics are so turbulent and

chaotic that future ecological events cannot easily be predicted.

James Drake has convincingly demonstrated that several alternative

states of ecological equilibrium are possible in a community due to

a species invasion despite identical initial conditions.

In summarYI one cannot easily make a predication of the impact of

a biological stressor in a new environment based on a linear

mechanistic micro-level examination of biological characteristics

of the org'anism (e. g. number of eggs it lays, ma1:ing behavior,

etc.) and/or the environment (e.g. identification of the various

components) • The reason is that the fundamental fabric of

ecosystems is probably not linear or mechanistic but non·-linear and

chaotic in nature.

However thEare are, on a more macro-level, certain characteristics

that have been shown to be useful in making predictions about

invasive species. One of the most important is that if an organism

has been shown to be invasive in other environments (successfully

establishing and spreading in other regions) there is an increased

probability that it will be invasive in a new similar, environment

(e.g. rats & man). Another example is, if an organism is closely

E-1l2
associated to its host and that organism occurs throughout its

host's historical range; then if you move the host to a new

location, the establishment of the organism is likely to occur if

it is introduced (e.g., crop pests & livestock diseases).

Note that when you approach the evaluation of biological stressors

from the macro-level you are not identifying why they are better

invaders, but just that they are.

This macro approach is admittedly filled with flaws. If used there

will be numerous mistakes and many incorrect predictions will be

made. But it does provide a more usable tool than the microevaluation approach does.

The proof, as they say, is in the pUdding. The Forest Service

conducted an extensive risk assessment on the biological stressors

associated with the importation of larch logs from Siberia in 1991.

The number of nonindigenous organisms identified that could move on

raw logs into the United States numbered more than 175. using a

combination of a macro-level/micro-level approach (see Orr ~, £1,

1993 for the process) the scientists identified 36 of the. 175+

organisms to be of enough concern to warrant detailed evaluations.

Since the assessment was completed, 3 of the 36 organisms have

entered the United States and established. None of the remaining

139 nonindigenous organisms assigned lower evaluation importance by

the scientists have entered the United States and established.

This indicates that the scientists were able to predict to a

certain degree which organisms would establish.

One of the three organisms identified by the scientists, was the

Asian Gypsy moth which was eradicated from the Pacific Northwest.

According to the Forest Service, having the assessment completed on

the Asian Gypsy moth, and therefore having all the involved parties

(federal, state, environmental groups) already aware of the

potential for damage from this organism saved an estimated minimum

of 30 million dollars in eradication costs. .

I am looking forward to the Ecological Risk Assessment Workshop .

.References:

FS, 1991. Pest Risk Assessment of the Importation of Larch from

Siberia and the Soviet Far East. USDA, Forest service,

Miscellaneous Publication No. 1495.

Orr, R., Cohen, S. and Griffin, R. 1993. Generic Non-Indigenous

Pest Risk Assessment Process -- For Estimating Pest Risk

Associated with the Introduction of Non-Indigenous

organisms. Draft USDA APHIS document.

OTA, 1993. Harmful Non-Indigenous Species in the United states.

U.S. Congress, Office of Technology Assessment.

September 1993

E-1l3

Review ofIssue Paper on: Biological Stressors

Issue Paper Authors: Drs. Daniel Simberloff and Martin Alexander

Reviewed by: Dr. James H. Thorp

I found this 52-page issue paper on biostressors to be quite informative and interesting to

read. I congratulate Drs. Simberloff and Alexander for their thorough contribution. While I do not

wish to suggest that I could have written a better paper, I will fulfIll my responsibilities as a general

reviewer by offering some suggestions for revisions in organization and content. At the end of this

review, I will also explicitly respond to reviewer questions 6-1 and 6-2 and to the general areas for

consideration (0-1 through 0-6), as posed in the pre-meeting notebook.

The authors are highly successful in illustrating the complexity of risk assessment for

biostressors and provide a wealth of biological examples (except for aquatic species, as discussed

later). This is not surprising given their credentials in this area of science.

Unfortunately, the authors' presentation has pessimistic overtone. Notice that I did not say

"overly pessimistic", because their tone, in fact, may be realistic and reasonable. Nonetheless, it is

not especially useful except to convince assessors that the job will not be easy. In reality, to answer

the fundamental questions of risk assessment, one must have some idea of what conn'ols the

distribution and abundance of organisms -- this is a phenomenally huge topic which currently

engages the activity of most ecologists! The authors conclude that the heavy use of examples and

an emphasis on kinds of effects are the best that risk assessment for biostressors can do (p. 6-38).

they also conclude that until significantly more ecological information is available, risk assessment

will remain speculative (p. 6-41).

My conclusion is that this paper is an excellent review ofthe problem, but it is not as

successful as a guide for resolving the problems of risk assessment. Its organization and emphases

do not lend themselves to identifying future research needs nor is it complete as a guide to risk '

assessment. This could be resolved in part by the better statement ofrelevant ecological principles

and the identification of testable hypotheses.

The following comments, occurred to me while reviewing various sections of the paper. I

apologize in advance for the relatively poor organization of these comments.

Section 2. This is a good section that should help environmental managers better

appreciate the differences between biotic and abiotic stressors. I believe, however, that this section

fails to list two important differences that are emphasized later; these are: (1) jump-dispersal

characteristics of some biostressors (essentially absent in abiotic sn'essors) (p. 6-22); and (2) the

great difficulty eliminating biostressors once a successful invasion has OCCUlTed (p. 6-43), in other

words, one cannot just tum off a pipeline for the original stressor and expect the problem to be

resolved.

Section 3.1. Here again the authors state that only a few generalizations are possible (p.

6-13). I would argue that we need to generalize in the fOlm of testable hypotheses as a means for

identifying future research needs. One might also analyze the relative impOltance offactors that

often limit survival and dominance.

Section 3.2. This section contains some imPOltant ideas that could be more clearly

emphasized and used as areas for research. For example, what are the relationships between

survival and proliferation in terms of: (a) prior habitat disturbance (p. 6-15); (b) inninsic rate of

increase (p. 6-16); (c) prior community complexity and resistance to invasion (p. 6-16); and (d)

primary versus secondary invaders (p. 6-17).

E-115
Section 3.3. An impOltant point is made here between the good applicability ofsimple

diffusion models for abiotic stressors and their poor applicability to biosnoessors. In palt this is due

to jump dispersal. Aerial dispersal is also apparently better modeled than aquatic dispersal.

Discussions of dispersal corridors (and blockage by environmental managers seeking to stop an

invader) and barriers to dispersal would be useful.

Section 4. The authors point out that empty niches probably never occur, but this

assessment is more applicable at the ecosystem process level. They correctly emphasize that we

have failed to adequately identify how one should select species or processes for assessment (p. 6-

24).

Section 4.1. We need more research on the relationship between the complexity of the

community and the severity of the subsequent invasion.

Section 4.2. Dose-response curves do not seem useful for risk assessment of

biostressors, as they point out.

Section 6. The authors present an interesting challenge to the concept that the effects of

genetically-engineered organisms are more easy to predict (p 6-39). This challenge could be very

important and is. worth further consideration.

Section 6.1. The early classification of potential or new invaders by survival,

reproductive, and dispersal characteristics and potential harm might be useful.

Section 7. Authors make interesting point that recovery judged by ecosystem

properties (e.g., carbon flow) might be much easier than determinations made for each population.

However, this g,eneralization is not adequately discussed or supported in this issue paper.

Response to uGeneral Areasfor Consideration"

G -1. Clarity of Purpose and Scope:

Sorry -- I found the "introduction" to be essentially useless as a "roadmap" to the

organization and major emphasis of the paper.

G-2. Completeness of Coverage:

Some ecosystem impacts of biostressors are mentioned (e.g., in the inn'oduction) but the

coverage at this level of complexity is minimal; however, this may reflect the intensity of scientific

studies rather than the biases of the authors of this issue paper. Both spatial and temporal scales

(e.g., evolutionary scale) are adequately addressed.

G - 3. Clarity and Consistency of Terminology:

The use ofjargon was not excessive, and the number of necessal)' conn·ibutions to a

glossary ofscientific telIDS would not be great. If a glOSSal)' is available, an explanation of the

relatively new concept of a "metapopulation" might be useful. Actually, readers aloe probably more

likely to stumble: over some of the literal)' terms than the scientific terms in this issue paper!

E-116
G-4 •. Current Capabilities vs. Future Needs:

I believe the paper's list of examples could be trimmed without significantly damaging the

thrust ofthe paper. On the other and, the paper is markedly weak in explicitly identifying future

research needs. Suggestions for research needs are not clearly separated in the text, making it

difficult for the reader to recognize, evaluate, and act upon recommendations.

G-5. Relationship to EPA's Framework for Ecological Risk Assessment:

This requires an analysis of all issue papers in order to give an infOlmed response. As I

have not yet read all the other papers, I must refrain from a direct response to this question at this

time.'

G-6. Examples:

The paper was strong on terrestrial examples (especially metazoa) but decidedly weak on

aquatic examples. For example, the Asiatic clam, Corbicula fluminea, has been extensively

studied, and it is an excellent example ofjump-dispersaL Human vectors of dispersal were not

classified. One current example is the exceedingly rapid movement of zebra mussels on barges

throughout much ofthe Mississippi River drainage. There was very little mention ofintroduced

fishes. Furthermore, the authors never mention the introduction of supposedly-sterile exotic

species, such as the grass carp, which occasionally causes significant damage when they suddenly

develop the ability to reproduce! Some mention of the reproductive habits of the introduced fish

Tilapia in relation to density would also be potentially usefuL

Questions Specifically Relevant to "Biostressors"

6-1. Balance

This issue paper was adequately balanced in coverage of exotic species macrobes and

genetically-engineered microbes, with one exception. The response of genetically-enginee:red

species was assumed to be essentially equivalent to introduction of "natural" species, except for

lateral transfer of genes. Unfortunately; the authors have not provided adequate examples of either

the introduction of genetically-engineered organisms or the process and likelihood of lateral gene

u·ansfer.

6-2. The Next Step

As I have identified in my general discussion, the authors have not adequately identified

future research needs nor have they mapped a strategy for risk assessment, other than the Delphic

process. This probably relates to the complexity of the problem. If the August workshop cannot

develop a plan for identifying research needs and an assessment strategy, tllen I recommend that

EPA and Versar commission additional issue papers and another workshop.

E-117

Ecological Recovery

Workgroup Leader:

General Reviewer:

General Reviewer:

Dr. James R. Karr

University of Washington

Dr. Patrick L. Brezonik

University of Minnesota

Dr. Randall Wentsel

U.S. Senate Committee on Environment and

Public Works

E-119

Review by James Karr

COMMENTS: Fisher and Woodmansee - Ecological Recovery

My comments here are largely in the form ofquestions. My goal is to stimulate the group to

focus on conceptual issues that must be clearly defined before we can advocate their use in

formulating societal policy. I also must admit some skepticism about the applicability of a number

of ecological theories and the constructs derived from them. The highway travelled by ecology as

a discipline is littered with cast-offtheory. How can we use but not be controlled by current

theory? How can we use the obvious signals from the world around us to develop more informed

societal policy whether grounded in current theory, observation, or both?

Page 7-6, paragraph 3, lines 1-3 (7-6,3,1-3) - The sentence specifically cites a laundry list of

issues and refers to a figure that contains two major sections (a and b). I do not see the

explanatory nature ofthe figure. Further, the meaning ofthe components in a and bare essentally

identical, suggesting that the spatial and temporalcollsiderations are not different except that

"spatial" and "temporal" substitute. Does the figure really simplify and make the issues more

transparent? I am not so sure.

7-6,3, Last few lines - The use ofsuccession here and elsewhere is a bit confusing. Is every

systematic change succession? For example, is the seasonal shift in herbs in the undergrowth a

succession? Same for phytoplankton in a lake or benthic invertebrates in a stream? How about

the migration ofbirds from place to place during the annual cycle? Or is the seasonal replacement

ofbirds in a single forest a succession? How do we place clear bounds on the use of concepts like

succession? Is that essential ifwe are to cast risk assessment in a broader ecological context?

General comment: The use of ecological concepts, theories, and principles is not consistent

among these papers. Ifecologists don't use these words consistently when communicating among

themselves, how can we expect others to use them in ways that will inform risk assessment and

communication?

7-9, 1,2 - The phrase "current state" here is vague. How do we decide what ecological or

biologically relevant attributes are to be measured to reflect state? We have the obligation to

measure those things that we know might be influenced by a human action. Should we also think

more broadly about unknown or unexpected effects? Should we be collecting information that

will help in recognition ofbroader effects than those currently envisioned? For decades we have

focussed on acute and chronic (especially cancer-causing effects) but new evidence suggests that

the developmental, immunological, and other effects may be far more ominous. Widespread

recognition ofmany other aspects ofdegradation are emerging? How do we do the best job to

anticipate the unexpected?

7-10, 1, last 4 lines - Excellent points here. How do we avoid conceptual approaches that are

constrained by current theoretical framework of ecology or risk frameworks developed to deal

with other issues and problems? I see problems with both in this and other papers in this series.

How can we focus on overcoming that problem as opposed to finding a convenient set of

bureaucratic rules that suggest but do not produce a solid risk assessment approach that will in

fact protect society's interests over the long term?

E-121
7-11,2, bullet:4 (second ~t ofbullets) - The switch from ecological context to ecosystem

context within :and among the papers in this set is a bit disconcerting. In some cases, population

issues are identified as important while in others, authors suggest that species loss is not of

consequence if"function" is maintained. That kind ofconclusion flies in the face ofmajor societal

energy to protect: species such as bald eagle, salmon, and spotted owls now and wood duck early

in this century. I find the varying signals within this paper and among the papers in this series

confusing. How do we resolve that?

7-14, 4, 4 - What is meant by the "viability" ofecosystems?

7-5,2, 1 - Biological integrity is introduced here as a concept without definition aIlld without

relating it to thl~ other concepts mentioned throughout this text. Should an agreement be reached

on what all these mean and how they relate to each other before they can be used in a formal risk

assessment context?

7-15, 4, 1 - An~ there other kinds oforganisms than "bioJogical organisms?"

7-16, 1, 7 - Is it your intent to equate biodiversity with diversity ofgenetic stock? Is the text

question here serious? How do we go about answering it?

7-17, 2, 6- To what extent are there or should we explore the possibility ofnon-economic values

ofecosystems? How do we incorporate ,our la~k orknowledge ofvalues that are nonetheless

important to society?

7-20,2, 1 - Is this a widely understood and accepted definition ofstability? ,What is the range of

"ecosystem resJPonse" that is relevant to this definition? Shrader-Frechette and McCoy (Method

in Ecology) have extensive discussion ofthe concept ofstability and its use in ecology. I think

that universe ofconcepts is broader than what is reflected in this brief discu~sion.'

7-21 - Much discussion ofwhat disturbance is and what it means here. They do not all agree or

even seem to focus on the same thing. How do we move toward consensus?

7-21, 3, 3 - What is the'~cycle of an ecosystem?"

7-22, 4 - Resistance - Has resistance ever been measured? How would we express it and define a

divergence from expected to infer a significant Unpact by human society? The same question

seems appropriate for resilience and other similar concepts. How do we translate those difficult

ecological conc:epts into something that can be used in formulating societal policy? In effect, how

do we measure it and use it in the policy process as opposed to thinking aloud about it as

theoretical ecologists?

7-24, 2, 4-8 - Ifall risk assessment is based in prior definition ofhuman-assigned values, how can

risk assessment protect us from the unknown consequences ofour actions. I have some thoughts

on this issue that can come out in our discussion. At the core, we have the current range of

environmental "train wrecks" because we did not do a very effective job of anticipation ofthreats

E-122
to human welfare as opposed to operating as ifhuman interests are not threatened by societal.

actions.

7-25, 1, 1-5 - I am not so sure that resistance and resilience are rigorously negatively correlated in

ecosystems.

7-25,2, 1 - Not clear to me how resistance is the only factor establishing initial conditions in the

recovery process.

7-26,3, last line - Not clear to me how a recently burned forest is immune to disturbance (all

kinds)? Is this meant broadly orjust immunity to another round offire? Is that true? Is it

idiosyncratic offire or would the same be true ofall kinds ofdisturbance?

7-27,2,8 - What is a "benthic half-cycle?"

7-28,3 - Good paragraph. The kinds ofissues raised here should come up earlier and more

forcefully. They are the core ofwhat we should be considering and evaluating as oppoed to the

more esoteric ecological concepts that may be impossible to measure such as resilience and

resistance.

7-29,2, 1 - stability - Has this been defined yet? How can the concept be used in the sense of'

someeone going out and measuring something in a biological systems and using that information

to make a decision based on that measurement? '

7-30 - What are the'emergent principles from the kinds ofexamples that are listed in this set of

paragraphs and those that follow?

7-30,4, 1 - "Fire is a'catastrophe"" What is meant by this? How iscatastophe defined? From

whose perspective? It is essential to many species ofplants and animals (as is noted in the next

sentence) and, thus, the lack offire would be a catasrophe. Is fire always'a catastrophe?

7-32,2, 1 - It seems to me that many fish in North America show considerable resistance to

drought. What they don't show resistance to is the kinds oflate summer'dewatering that is

characteristic ofstreams after human-alteration oflandscapes, stream channels, and water tables.

7-35, 2, 3 - Phenology is used here. Forsome earlier usages ofsuCcession in this text, it seemed

more appropriate to use phenology to me. How do we sort out those things in text thatis

~esigned to inform and be used by policy makers?

7-35,2- The die-offofDiadema in the Caribbean some years ago is an excellent example ofthis

kind ofthing. Should be cited here.

7-36,2 - Good points about scale here. Perhaps they should be expanded.

E-123
7-37, bullets - Seems an odd list to me. Tendency to focus on (plant?) biomass is a bit narrow.

This reflects an ecosystem level perspective rather than a broader ecological perspective. What is

the intent ofthis: risk assessment process with respect to that issue? Is ecossytem, ecological, or

biological the driving interest?

7-37,2, 1-2 - I ~un not so sure terrestrial systems subjected to airborne agents wi111begin recovery

immediately.

7-38, 1, 1-2 - Is shift to more autotrophic endpoint recovery? Or is recovery to the original

condition? ChaJllge to anything is recovery ifthe former. How and when do we decide which

should apply?

7-39, 4, 1 - What is an "ecosystem population?"

7-39,4,4-5 - What is the lesson and emerging principle ofthe Chapin and Chapin example?

Later "successfhl recovery is a function ofphysiology." What does that tell us. It is also a

function ofthe (lvolutionary experience with that disturbance? The context ofother disturbances

then and as antecedent conditions. How do we use all this to make decisions and to anticipate the

future needs of:;ociety and what risk assessment should be designed to protect us from?

7-40, 3, 8 - How do you and Connell and Slayter define the four concepts listed here? How do

they relate to the subject at hand? They seem to hang here with no purpose.

7-41,3,2 - Odu:tn citation and leakiness. How do we define an appropriate level ofleakiness? It

surely is not the same for all biological systems?

7-42, 2, 3 - What are the 8 processes ofVitousek et al? How do they relate to the subject at

hand?

7-42,4, last sentence - What is the lesson ofthis? Does that distiguish it from other levels? Does

that make measurement at ecosystem level less useful? Not useful?

7-43, 1, last couple lines - Is it only collective properties that we are interested in? Why? Is that

reflected in the l:anTent movements in society to protect ecological mtegrity or ecological health

(they are not thc~ same in my view)?

7-43,2,2,5 - "state variable" - I suggest that this is much too narrow a perspective for

ecological risk evaluations.

General comment - I think we should explore the following question: How dependent is risk

assessment with the constructs used in this and other texts on the current round ofecological

thoery? Should the risk assessment process be driven by that theory alone? Should that theory be

abandoned in favor ofmore general, perhaps even simple, observations ofthe changing biology of

a site influenced! by humams? Can any good biologist detect most ofthe most serious forms of

degradation that result from human actions without resorting to resilience or resistence,

E-124
ecosystem theory or population demographic models? Should we use both and try to establish

when each kind ofapproach is most relevant or important?

7-44, section 5.2.1 - I have serious reservations about this section. They are grounded in

ecology and in the kinds ofvalues that many in society express independent ofthe functional

equivalence arguments ofsome kinds ofecology.

Many other comments are noted in the margin ofthis manuscript. These thoughts raise some

general issues that apply here but also apply to other papers as well. Rather than separate them

into two sets ofcomments I have hinted at the broader, cross-cutting issues in these notes.

JamesR Karr

University ofWashington

E-125

Review of Chapter 7. Issue Paper on Ecological Recovery

for

Risk Assessment Forum's

Ecological Risk Assessment Workshop

August 16-17, 1994

by

Patrick L. Brezonik

University of Minnesota

Overview

This chapter contains many good ideas and worthwhile suggestions regarding the analysis

of ecosystem recoverability in the context of ecological risk assessment. However, the text

also is encumbered with jargon, undefined terms, and unhelpful generalities. The authors

have attempted to lay a comprehensive framework for the analysis of ecosystem recovery;

perhaps in so doing they have sacrificed specifics and detail for broad and often vague or

abstract statements. The paper provides a useful discussion of concepts that should be

considered in conducting the recovery analysis phase of a risk assessment, but it does not (in

most cases) describe how these concepts should be considered or used in the assessment.

Consequently, the agency or person doing the risk assessment is left with no concrete guidelines. Overall, there is too much emphasis on natural agents of disturbance and the recovery of ecosystems from such disturbances as flooding) and insufficient focus on anthropogenic agents of disturbance and the responses/recovery of ecosystems from such agents.

The authors are to be commended for the broad framework they provide, particularly in

including the socio-economic dimensions of the analysis.

General Areas for Comment

G-1. The introduction is nicely written, particularly the first couple of pages. However, I

don't think it provides much of a roadmap to inform the reader as to the organization of

the for the rest of the paper. The roadmap, such as it exists, is embedded in the first full

paragraph on p. 7-8. I think this could be expanded somewhat and made more specific.

G-2. As stated above, I think the authors have attempted to be comprehensive, but their

coverage of different types of stressors and different types of ecosystems is not well organized; the paper is organized along other lines, and inclusion of various kinds of stressors

and ecosystems is mostly by way of example (and consequently somewhat haphazard). I

would like to see more emphasis placed on describing recovery processes for different

categories of ecosystems from various classes of stressors.

G-3. I make specific comments on undefined and inconsistent terminology in the detailed

comments that follow. There are problems with both issues in the paper. A glossary may be

useful, but where possible I think it would be better to: (1) avoid the use of jargon and

terms that are used only by specialized scientific groups, and (2) define terms as needed in

the text.

G-4, G-5. I have not had time to analyze the paper sufficiently to respond to these items.

E-127
Chapter 7 Review/p. 2

G-6. There are no case studies given in the paper. The use of examples or illustrations is

limited to hypothetical or abstract situations/systems or to amplify a specific issue. For

example, in discussing physical factors affecting resistance to change and resilience to

recovery in streams, the authors briefly discuss differences among cobble-rock bottom, sand

bottom, and clay..rich streambeds. In discussing organismal adaptations, jack pine is mentioned as an example of an organism that has a mechanism of resistance that operates at the

level of genomes. Many other such "examples" are scattered throughout the text. However,

no ecosystem recovery studies are cited or discussed. The paper could profit by inclusion of

some specific case studies where recovery happened as predicted or didn't happen (and why

it didn't).

Questions Rele,'ant to Issue Paper 7.

7-1. As noted in G-6, the paper does not have specific examples of recovery (i.e. case

studies) or much detail about specific recovery processes in any ecosystem types. Within the

framework in which the paper uses examples (see response G-6), the paper is short in providing examples related to lakes and wetlands.

7-2. There is very little discussion about recovery of ecosystems from chemical stressors.

There is no dis(~ussion about recovery of lakes from eutrophication or acidification. There

is little or no discussion about natural recovery (once a stressor is removed) versus manipulations to acce:lerate recovery. In the context of lake acidification, addition of powdered

limestone is an example of the latter approach.

Obviously, many examples could be provided with regard to recovery from anthropogenic

stressors. This would make the paper rather different from the present version. Given.

EPA's mandates regarding anthropogenic impacts, I think the paper should include a lot

more examples on this topic.

7-3. Paleolimnological methods are not mentioned as a technique to infer past conditions in

lakes (hence determine what the target should be for recovery and whether the lake has

recovered).

7-4. The paper does a fairly good job of addressing socio-economic factors that affect the

likelihood of recovery. The sections on cultural influences (3.2.3, p. 7-18) and politics,

policy, laws and regulation (3.2.5, p. 7-19) are vague and very brief. The section on

economics could use additional references and perhaps additional text.

7-5. No commlmt at this time.

Specific Comments and Questions on Chapter 7

p.5-6 This is a nice introduction.

p. 7 The ideas espoused in the first full paragraph are interesting and in an ideal world

they make sense. Realistically, however, they imply that we know a lot more about the

"typical ecosystem" requiring restoration than is likely to be the case and more about the

range of states available for "endpoint selection" than we do, and that we can exert finer

control over which of these states is reached than is the case with our current (crude) tools.

In the real world, we are likely to have only general information about the nature of the

E-128
Chapter 7 Review/ p. 3

ecosystem before stress and damage occurred. At least in the case of aquatic ecosystems,

much of the information on the nature of the endpoint state (the restoration goal) is likely

to be from analogous ecosystems rather than from the system to be restored. Overall, I

think this paragraph implies that we have more detailed understanding about ecosystems

responses to stress and a finer degree of control over ecosystem restoration than is actually

the case.

p. 7 It is perhaps a minor and subjective point, but I do not care much for the term "risk

assessor", first used in line 6. (Perhaps it reminds me of tax assessor!) Are we going to

develop a new profession or category of government employees called risk assessors (with

grades I to IV); I hope not.

p. 8 In my opinion, the final steps in the protocol (second last paragraph) not only are

beyond the scope of the paper but beyond the ability of ecosystem managers and restorers to

achieve at present. Again, this seems not to be a realistic recommendation (cf. first comment on p. 7).

p. 12 The first sentence does not make a lot of sense to me. I am puzzled by the statement

"Since recovery from that stress can easily take'on prominence." What point are the authors

trying to make here?

p. 12 Second paragraph line 4. The word "sector" is rather vague and is used elsewhere in

the chapter to mean other things (e.g. see p. 8, line 5). I think the authors should find a

more descriptive term for the ten factors or sets of issues they say need to be included in

the analysis.

p. 14 The first sentence could be improved by rewording or re-ordering the ideas it

includes.

p. 14-15 The sections on water and soil properties are very vague and general. There is

little useful information here, particularly with regard to implications for assessing/predicting recovery. It would be better if the authors provided some examples for different

categories of ecosystems (e.g. aquatic [lakes, streams], semi-aquatic [wetlands], terrestrial

[forests, arid lands, etc.]).

p. 15-16 The section on assemblages of organisms is better than the two previous sections,

but it too could be enhanced by more examples for different categories of ecosystems.

p.17 The second paragraph implies that recreation has only a nonmonetary value with regard to ecosystems. This is true only in part. Economists have spent a lot of time and effort

developing monetary-based values for recreational use of aquatic ecosystems, and there are

many studies that demonstrate high monetary values associated with recreational use of

rivers, lakes, reservoirs, etc.

p. 18 The first paragraph (on cultural influences) is very vague. To start, the authors need

to define what they mean by cultural communities, cultural viability, and cultural trends.

p.18 Second paragraph, line 4: Change "Thus..... to "For example, .....

p. 19 The paragraph on politics, policies, law and regulation is so vague as to be useless.

The first sentence is a true but general statement. The second statement is unclear. The

third and last sentence is meaningless.

E-129
Chapter 7 Revi.ew/ p. 4

p.20 I do not think it is useful to repeat definitions from the 1970s literature that are no

longer accepted. The authors state that there is some confusion about the definition of

stability, but they may unwittingly contribute to that confusion in some readers' minds by

repeating Holling's definition.

p.20 Section 4.1.2: The section is not just about disturbance and stress; perturbation is

introduced as 11 comparable term (on p. 21, third paragraph): It would be better simply to

label this section "Disturbance" or "Disturbance and Related Terms (or Concepts)".

p.20 Section 4.1.2, line 1: Define punctuated and differentiate it from discrete.

p.20 Last linE! of page: define spate; most readers are familiar with this term in the sense

of "a large number or amount of" or "a sudden rush or outburst"; the primary definition in

Webster's Unabridged Dictionary (Le. a flood or freshet) seems less common in use, except

perhaps among stream ecologists. Why not use the word flood here?

p.22 The third paragraph (Thus the first step...) needs some work. The authors say that the

disturbance must be described fully and must include consideration of disturbance attributes that formerly were dealt with in an arbitrary and conflicting manner. How do they

propose to consider these attributes in a non-arbitrary and non-conflicting manner?

p. 23 Second paragraph of Section 4.1.4: The seasonal examples provided are trivial. Would

any ecologist or resource manager expect to restore a system to a perpetual'spring-time

condition?

p. 23 Last parllgraph, line 3: Why add to the confusion; delete reference to Holling's

definition. See first comment 'ror p. 20 above. '

p.24 I am not convinced that the Odum concept of ecosystem development presupposes a

cybernetic function for ecosystems. I also am a little amused by the author's critical

language with regard to Odum's term (e.g. "dubious value", "uncertain origin") and generally

positive statements about Margalef's similar views ("uniquely ecosystem-oriented", and

"concept is us(~ful"). What gives here?

Rather than criticizing the ecosystem-level trends of Odum as non-universal or inapplicable, perhaps it would be better to describe the concept of succession differently for

autotrophic al1d heterotrophic ecosystems.

p.2S Line 1: ][ think the authors mean to say that resistance and resilience are negatjvely

correlated in l~cosystems. The third sentence of the first paragraph ,is a non sequitur.

p.2S Second paragraph: Resistance to stress or disturbance defines the initial conditions of

the recovery process only in part; the amount or severity and longevity of the stress also

playa defining role in the nature of the disturbed or degraded ecosystem. In the third

sentence of this paragraph, the authors say that the most important variable for predicting

recovery capacity is the system's state once the stress has been removed. A state is not a

variable (except in the context of models -- "state variables"); a different word would be

better. The last sentence of this paragraph is not clear, especially the point about

"weighting telrms".

p.2S Section 4.2.1.1: The streambed examples provided in the paragraph dealing with

physical factors seem to contradict the earlier statement on p. 25 that resistance, and

E-130
Chapter 7 Review/ p. 5

resilience or negatively correlated. A boulder-cobble bottom would provide high resistance

and high resilience; a sandy bottom would have lower resistance and lower resilience; but a.

clay bottom would have high resistance and low resilience.

p. 26 The paragraph about physical factors affecting resistance of lake ecosystems is simplistic. It ignores all chemical factors and seriously understates the physical complexities of

lake ecosystems. I suspect that the brief paragraph on terrestrial ecosystems also oversimplifies physical factors. It does not include any consideration of geochemical conditions..

p.27 First paragraph: The second a.nd third sentences may be clear to terrestrial ecologis~s;

I don't think they are clear to others.

p. 27 Second paragraph: I don't understand what the authors mean (l~ne 11) by "floods

remove the benthic half-cycle in such ecosystems."

p. 28 Line 6-7: This sentence is unclear and needs further explanation/description.

p. 31 The section on disturbance type is too long for the amount of relevant information. It

focuses too much on natural disturbances and stresses, almost to the complete exclusion of

anthropogenic disturbances; the latter, I presume, are of the greatest interest to the EPA. I

frankly do not understand the focus on flooding and other natural disturbances. Many of

the examples in this section appear to describe responses or recovery of ecosystems from

seasonal events like spring flooding. I don't see much relevance of this material to the

subject of ecological risk assessment or to ecosystem recovery from anthropogenic stress.

p. 31 Section on animal-caused disturbance: The first clause of the first sentence inthis

section is unclear to me. Beavers are an importantexample of natural biological agents.

whose resurgence is causing significant disturbance in aquatic ecosystems of the upper

Midwest.

p.33 Section 4.2.2.2: This section is too brief and only discusses some differences between

natural and anthropogenic stresses. It should provide a more in-depth discussion of the

types of anthropogenic stresses and how they differ among themselves in ecological impacts.

p.34 First paragraph: No mention is made of excessive nutrient additions to aquatic

systems and acid loading to forest and aquatic ecosystems from atmospheric deposition.

These are two of the most widespread anthropogenic stresses, ~nd ecosystem responses to

these stresses are fairly well understood. Aside from physical (habitat) disturbances, these

are probably the most common anthropogenic causes of aquatic ecosYstem degradation leading to restoration actions in the U.S.

p.34 Line 9: There are many reasons to believe that a flood-damaged stream and a stream.

damaged by a petrochemical spill will not recover in the same way. For example, the flooddamaged stream may suffer considerable habitat loss or change. A petrochemicalspill may

or may not involve any habitat damage, depending on the nature of the spill; in any case,

the type of habitat damage is likely to be rather different in the two types of disturbance.

p. 35 The examples provided in the first paragraph are largely irrelevant to the needs and

interests of EPA with regard to ecosystem disturbances. I don't think that time scales on the

order of time-of-day or even season are particularly relevant to what should be the focus of

this paper -- even though such scales of course are of considerable interest to ecologists in

understanding the detailed behavior of ecosystems.

E-131
Chapter 7 Review/ p. 6

p. 36 Line 13 from bottom: I disagree strongly with the contention that transparency is not

an issue in the cited example. If macrophytes have been lost from the system for some

reason, there is a good possibility that nutrient concentrations will have increased in the

water column a.nd algal growths also will have increased. Transparency thus will have

changed from the predisturbance condition. The example is at best a simplistic application

of the statistic~l1 findings of Duarte (1991).

p. 37 Section 4.2.5: The first sentence strikes me as a non sequitur; remove the word

"Although" and rephrase the sentence as two independent clauses.

The four bullets are not discussed adequately in the subsequent paragraph and need more

explanation and/or examples. It is not clear how the first sentence of the paragraph following the bullets acts as an example; the phrase "For example," should be removed. Also, I

don't think the idea expressed in this sentence can be justified. If the airborne agent is a

toxic substance: that has accumulated in the soil or biota, it may take many years for it to be

flushed from the ecosystem, just as the authors say is the case for lakes.

p. 38 Line 7 from bottom: Define "vagile".

p. 38 Line 2 from bottom: Another flood example. Can the authors provide an example involving an anthropogenic stress?

p. 39 Lines 13..15: This sentence is a bit unclear and could be improved by rephrasing.

p.40 Section 4.2.7.2: It would help the reader understand this section if the authors would

provide some examples of the assembly rules to which they refer throughout the section.

p.41 Section 4.2.7.3: Most of the available energy in the aphotic zone of lakes (middle of

first paragraph) is autochthonous in the sense of being produced within the lake (in the

euphotic zone). Limnologists distinguish between autochthonous and allochthonous on the

basis of whether the material is formed in the watershed or in the lake. A material is

considered to be autochthonous regardless of where in the lake it is actually produced.

p.45 First paragraph: The idea that introduction of exotic species supports the contention

that some species are more important than others is not well developed and needs further

explanation.

p.45 Third pflragraph: Use of the word "reservoir" in line 2 is unclear until one reads the

rest of the paragraph. I think it could be deleted from the parenthetical phrase.

p.47 Line 4 f,rom bottom: The phrase "Relay filtration" is unclear and should be replaced.

p. 47 Last Iin4~: Change "short-cut measures such as redox" to "simple measurements such as

redox potential [or redox status)".

E-132
ISSUE PAPER ON ECOLOGICAL RECOVERY

Review by Randall Wentsel

The paper on ecological recovery 1s well written and

provides a very good overview of questions, issues, and term~nology in ecological risk assessment (ERA) and r~sk

management of damaged ecosystems. The authors also show how the

Framework for ERA can structure the complex issues concerning damaged ecosystem recovery.

One issue that should be stressed is that scientists arA not

the only stakeholders in deciding what the best endpoints are 'and

deciding what the best ways to get the ecosystem Ilback on track.·t

Non-science issues and valu&a h~ve an important ro~e in risk

management. The authors stress this in the Problem Definition

section with the 10· basic sectors. These sectors are inclusive

of many ot the stakeholder issues ~n environmental management. '

The issue of organizational viability (NOT a biological indicator) recognizes the long term economic, Bocial, and

political stability required to maintain an ecosystem recovery

program. Policy issues and regulations can bGused to support

remediation efforts.

While an ecosystem will undergo a natural succession,

think further discussion of the uncertainty of managed or

remediated ecosystem recovery would be beneficial. Methods to

aid the recovery of an ecosystem could produced unexpected and

undesired results. The point the authors made that - ecosystems with a high oapacity to resist stress tend to hav~ a l:im:l tp-d

ability to recover from the disturbance events and vice versa - is important to remember.

The section on natural versus anthropogenic stresses

discussed how anthropogenic stress can be superimposed on stress

systems and alter ecosystems in dramatic and unpredictable ways.

It emphasizes the impacts from toxic chemicals and exotic

organisms.

'l'he authors discuss the importallt issue of monitoring an

ecoeyetem for recovery. They recognize that there are no

standard methods to assess recovery and that managers and

scientists must be involved in designing the monitoring program.

Discussions on recovery and its theoretical basis were well

done. The role of corridors and size of habitats was not

emphasized. However, natural succession was well presented.

More discussion of keystone species, "hot spots," and critical

habitat could be includod. Judging the effeot~venesa of thQ

recovery needs to include a broad group of stakeholders.

E-133
OVerall the authors presented a complex subject in a

readable manner. The Framework assisted, not hindered, the

presentation of the information.

E-134
Uncertainty in Ecological Risk Assesslnent

Workgroup Leader:

General Reviewer:

General Reviewer:

Dr. A. Frederick Holland

South Carolina Marine Resources Institute

Dr. Lev R. Ginzburg

Applied Biomathematics

Dr. Kenneth A. Rose

Oak Ridge National Laboratory

E-135

Review by Lev Ginzburg

Paper #8: Uncertainty propagation methods

Although the papers are not intended to be comprehensive, I think the paper should

review the variety of uncertainty propagation methods. These techniques should at least

be mentioned.

DELTA METHOD (Seber 1973; Kirchner 1992) is an approximate method based on a

Taylor expansion for finding approximate means, variances and covariances of functions

of random variables.

DEMPSTER-SHAFER TI-:iEORY (Shafer 1976) is a calculus for weighing evidence that is

widely used in computer science. It has fewer assumptions than probability theory and

is therefore a weaker, put more general, theory. I know of no examples of the use of

Dempster-Shafer theory in a risk analysis problem, although the theory is likely to have

substantial utility there.

DEPENDENCY BOUNDS ANALYSIS (Glaz and Johnson 1984; Frank et al. 1987;

Williamson and Downs 1990; Ferson and Long 1994; Ferson and Burgman 1994; Ferson

1994) is a numerical method by which bounds on probabilities can be computed when

joint distributions are unknown and only marginal distributions are specified.

FUZZY ARITHM:ETIC (Kaufmann and Gupta 1985; Ferson and Kuhn 1992; 1994; Kuhn

and Ferson 1994) is a generalization of interval analysis based on possibility theory

(Zadeh 1978; Dubois and Prade 1988). It is analogous to probability theory but applies to'

non-statistical uncertainty such as measurement error.

INTERVAL ANALYSIS (Moore 1966; Alefeld and Herzberger 1983) is a generalization of

range arithmetic. This is probably the simplest comprehensive method for uncertainty

projection through mathematical expressions.

LAPLACE AND MELLIN TRANSFORMS (Springer 1979) are standard methods for

probability distributions by which additive and multiplicative convolutions can be

computed by simple addition. This approach doesn't work with arbitrary distributions.

MONTE CARLO METHODS, including simple and structured sampling strategies such

as Latin hypercube sampling, (Iman and Conover 1980; 1982; Iman et al. 1981a; 1981b;

Iman and Shortencarier 1985) are approximate but robust simulation techniques for

convolving probability distributions of specified shape and (rank) correlation structure.

Iman and Helton (1985) describe the use of these methods.

RANGE ARITHM:ETIC (Dwyer 1951) is a simple method often used in physics to propagate uncertainty expressed as ± ranges through the basic arithmetic operations (plus,

minus, times, divide).

References

Alefeld, G.; Herzberger, J. (1983). Introduction 1Q Interval Computations. Academic Press, New

York.

Dubois, D.; Prade, H. (1988). Possibility Theory: An Approach ill Computerized Processing Qf

Uncertainty, Plenum Press, New York

Dwyer, P. (1951). Linear Computations. John Wiley, New York.

Paper #8 Risk Assessment Forum Issue Paper Review

E-137

Ginzburg
Person, S. (1994). Naive Monte Carlo methods yield dangerous underestimates of tail probabilities. PrQceedF~Qf.thf High CQnsequPJill: SympQsium. Sandia NatiQnal LabQratQries.

Person, S.; Burgman, M. (1994). CQrrelatiQns, dependency bQunds and extinctiQn risks. BiQIQgical

ConservatiQn [in press].

Person, S.; Kuhn, R (1992). Propagating uncertainty in ecological risk analysis using interval and

fuzzy arithmetic. CQmputer Techniques in EnvirQnmental Studies IV, P. Zannetti (ed.),

Elsevier Applied Science, LQndQn, pp. 387-401.

Person, S.; Kuhn, R (1994). Interactive micrQcomputer sQftware fQr fuzzy arithmetic. PrQceedings

Qf.thfHigh~Qnsequence Safety SympQsium. Sandia NatiQnal LabQratQries [in press].

Person, S.; Long, T.P. (1994). CQnservative uncertainty prQpagatiQn in envirQnmental risk

assessments, EnvirQnmental TQxicQIQgy ill1d Assessment. VQI a. ASTM STP 121.B, J.S.

Hughes, G.R Biddinger, and E. MQnes (eds.), American SQciety for Testing and Materials,

Philadelphia, [in press].

Prank, M.J.; NelsQn. RB.; Schweizer, B. (1987). Best-pQssible bQunds fQr the distributiQn Qf a

sum-a problem of KolmQgQrQv. PrQbability TheQry and Related Fields 74:199-211.

Glaz, J.; JohnSOln, B.M.K. (1984). PrQbability inequalities fQr multivariate distributiQns with

dependence structures. !Qumal.Qf the American Statistical Association 79:436-440.

Iman, RL.; ConQver, W.J. (1980). Small sample sensitivity analysis techniques fQr computer

models, with an application to risk assessment. Communicationsin Statistics A9:1749-1842.

Iman, RL.; Conover, W.J. (1982). A distribution-free apprQach to inducing rank cQrrelation

among input variables. CQmmunicatiQns in Statistics B11:311-334.

Iman, RL.; Helton,J.e. (1985). A ComparisQn.Qf Uncertainty and Sensitivity Analy~Techniques

ku: CQmputeJ: MQdels. (NUREG/CR-3904, SAND84-1461), Sandia National LabQratQries,

Albuquerque, New MexicQ.

Iman, RL.; Helton, J.e.; Camp1:?ell, J.E. (1981). An apprQach to sensitivity analysis of cQmputer

models, Part 1. Introduction, input variable selection and preliminary variable assessment.

!oumal.Qf~!i!.lli.yTechnology 13:174-183.

Iman, R.L.; Helton, J.e.; Campbell, J,E. (1981b). An apprQach to sensitivity analysis of computer

models, Part 2. Ranking Qfinput variables, response surface validatiQn, distributiQn effect and

technique synopsis. Joumal of Ouality Technology 13:232-240.

Iman, R.L; Shortencarier, M.J. (1984). A Fortran 77 Program and User's Guide.fQr~Generation

.Q.f1ill:in~rcubeand Random Samples for Use with Computer Models (NUREG/CR-3624,

SAND83-2365), Sandia National Laboratories, Albuquerque, New Mexico.

Kaufmann, A.; Gupta, M.M. (1985). IntrQduction to Fuzzy Arithmetic: Theory and Applications.

Van Nostrand Reinhold, New York.

Kirchner, T.R (1992). OS-CALC: .An Interpreter fur Uncertainty Propagation. Quaternary Software, Fort Collins, ColQradQ.

Kuhn, R; Ferson, S. (1994). Risk Calc: Uncertainty Analysis with Fuzzy Arithmetic. Applied

Biomathematics, Setauket, New York.

Moore, R.E. (1966). Interval Analysis, Prentice-Hall, EnglewQQd Cliffs, New Jersey.

Seber, G.A.P. (1973). The EstimatiQn.Qf Animal Abundance. Griffin, LQndon.

Shafer, G. (1976). A Mathematical TheQry Qf Evidence. Princeton University Press.

Springer, M.D. (1979). Ib.e Algebra.Qf Random Variables. Wiley, New YQrk.

Williamson, R.e.; Downs, T. (1990). Probabilistic arithmetic I: numerical methods for calculating

convolutions and dependency bounds, Intemational JQumal of ApprQximate ReasQning

4:89-158.

Zadeh, L. (1978). Fuzzy sets as a basis for a theory of pQssibility. Se.ts Systems 1:3-28.

Paper #8 Risk Assessment Forum Issue Paper Review

E-138

Ginzburg
Paper #8: Kinds of uncertainty

While there have been many comprehensive taxonomies of the varieties of uncertainty

published (e.g., Faber et al. 1992), the main subdivisions are basically of two kinds: variability and ignorance. Variability includes stochasticity arising from temporal and

spatial heterogeneity in environmental factors and among exposed individuals.

Ignorance includes measurement error, indecision about the form of the mathematical

model or appropriate level of abstraction. It's clear that variability and ignorance are

fundamentally different since the latter but not the former can be reduced simply by

additional empirical study. Variability can be translated into risk (Le., probability) by the .

application of a probab!listic model. Ignorance per se cannot be strictly translated into

probability in the same way. It can be used, however, to generate error bounds on the risk

statements. The two kinds of uncertainty have to be handled separa'tely, and differently,

in an ecological risk assessment.

Most analyses of population viability estimate the risk of extinction by estimating the

probability of extinction under random environmental variability. This approach is

sUfficient only ifthe demographic rates, and the magnitude of their year-to-year fluctuations, are known reasonably precisely. However, such knowledge is rarely available

in empirical situations: even in fairly unchanging environments there can be

considerable uncertainty associated with the estimate of each demographic rate. Indeed,

it is not uncommon that the variance in some variable due to measurement error is an

order of magnitude greater than that due to year-to-year fluctuations. The effect of such

uncertainty is to blur any projected population trajectory, even when the environmental

variability is known completely. This blurring increases with time, rendering long:term

projections particularly susceptible to uncertainties in the, original estimates. More

precise estimates of the demographic rates would result in narrower bundles of trajectories, and a longer horizon for making meaningful population projectionS.

The distinction between measurement error and naturalvariability can be described as

the difference between uncertainty about the current value of the parameter anduncertainty about future changes in a parameter. If a parameter contains random vaiiation,

uncertainty about future variation is inevitable and may often be significant. For

instance, a population that, on average, maintains itself adequately can be driven extinct

by a 'series of bad years, and one job of risk assessment is to estimate the likelihood and

probable impact of such a series. However, inaccuracy in the current estimates of vital

rates can give projections that inevitably diverge from the actual course of the population, whatever the extent of environmental variability. Measurement error of the

temporal variability of the vital rates also exists and may be fairly large. Considering it,

however, would require a second-order approximation which we do not address here.

Tossing a coin provides a good illustration of the effect of measurement error on risk

analysis. If the probability of tossing heads is known to be p and the probability of

tossing tails (l-p), well known statistical results concerning the binomial distribution give

both the expected number heads after n tosses and the probability that the number of

Paper #8 Risk Assessment Forum Issue Paper Review

E-139

Ginzburg
----------

heads will exceed the number of tails by some quantity. We are able to perform a perfect

risk analysis for any criterion of risk that we set for ourselves. The particular sequence

of outcomes in n tosses is analogous to natural year~to-year variability in the environment. The solid curves in the figure show that the uncertainty about the result increases

as the square root of the number of tosses.

200

100

.. ' .... .... .... .... .... .... "

.... .... .... .... .... .... .... .... .... .... .... ......

---------:------,--

-1 00 +--T--""-~r-"""'---r-...,.-__-...,...-..,.....-..---ro 1000

Number of coin tosses

2000

Comparison ofthe uncertainties in coin tossing due to measurement error and

due to natural variability. Solid lines are for p=0.50, dashed lines for p=0.54.

Each set shows the calculated probabilities of the expected excess of heads

over tails and the ranges within which the excess is likely to lie 95% of the

time. The ranges expand as the square root of the number of tosses, while the

expected means diverge linearly. An initial error of 4% in the estimate of p

(0.50 instead of 0.54), yields an excess that, on average, is no longer within the

95% probability range after about 200 tosses; after 700 tosses, the 95% ranges

no longer overlap at all.

Now suppose that the initial estimate of p was slightly inaccurate. At first, the difference

between the actual and the expected tosses is negligible. Their divergence is linear,

however, so that the eventual excess of heads over tails lies well outside the predicted

range. Although the analogy between coin tossing and population dynamics is only

heuristic, it suggests that measurement error can playa dominant role in limiting our

Paper #8 Risk Assessment Forum Issue Paper Review

E-140

Ginzburg
ability to project population trajectories into the future. In general, for long periods of

time measurement error may be a dominant cause of our uncertainty about the future,

while in the short run natural variability may dominate.

Our analysis of the population dynamics of the spotted owl shows that measurement

error dominates in 100-year abundance projections. Crudely speaking, the risk of

extinction in 100 years is somewhere between 0% and 100% (not a very informative

statement!) because the best available estimates of the mean survival values have significant measurement errors. We can be much more informative on a time scale of 20 to 30

years.

Whether or not ecological risk assessments are expressed in terms of probability statements, all conclusions must be stated with clear reference to their reliability (cf. Finkel

1990; Roberts 1990). Any conclusion lacking this reliability statement should be regarded

as nonsensical since we have no way to judge its meaning. Uncertainty analysis of

measurement error should be used to put error bars on our probabilistic risk estimates.

References

Faber et al. (c1992). Toward an open future: ignorance, novelty and evolution. Ecosystem Health:

fm: Environmental Management Costanza, R.; Norton, B.G.; Haskell, B.D. (eds.),

Island Press, Washington, D.C.

Finkel, A. (1990). Confronting Uncertainty in Management. Center for Risk Management,

Resources for the Future, Washington, D.C.

Ginzburg, L.R.; Goldwasser, L.; Ferson, S. (1994). Ecological risk assessment for the northern

spotted owl on the Olympic; Peninsula. [in preparation].

Roberts, L. (1990). Risk assessors taken to task. Science 248:1173.

Paper #8 Risk Assessment Forum Issue Paper Review

E-141

Ginzburg

K.A. Rose - Issue Paper 8 p.l

Peer Review of Issue Paper on "Uncertainty in Ecological Risk Assessment" by

E.P.Smith and H.H. Shugart

Kenneth A. Rose

Oak Ridge National Laboratory

Overall.-- I think the paper contains most of the relevant information but requires

significant editing, better choice of examples, and more synthesis. There are also

some technical aspects I would like to see addressed. The authors have done a

good job of assembling the ingredients for a good issue paper, but more work is

required. I think the Framework is very well written and I did not get much more

insight into uncertainty in ecological risk assessment from the Issue Paper than I

had gotten from the Framework. The case studies are important to bridge the gap

between generality (in the Framework and Issue Papers) and specificity (needed for

someone faced with performing or reviewing an ecological risk assessment). For

the Issue Papers to be useful, they must be very closely linked with the case

studies.

8. Editing.--The paper needs a thorough rewrite. Topic sentences do not always

match the major contents of paragraphs; some sentences should be clarified or

deleted. For example, the'second paragraph on page 8-8 begins with "For

example, a typical model for demographic analyses would be in the form of

ordinary differential equations for each population's numbers." and ends with the

sentence "Biology and ecology involve the relationship between geometrical

structures of living things and attendant processes.". Terminology is also a little

confusing. The paper tries to parallel the Framework and does successfully in the

beginning, but then deviates until by the last section on Risk Characterization I had

difficulty overlaying the Framework on the Issue Paper. The paper reads as if the

two authors wrote separate sections which were then just put together. For

example, in Section 2.4 Conceptual Model Formulation we see a list; why a list

formatted this way here and only here?

G-6. Examples.--The examples selected by the authors are not always good

examples. It appears the authors relied heavily (perhaps too heavily) on their own

work for examples, rather than using other more relevant examples from the

literature. Also, the use of examples is uneven in the different sections of the.

paper. Some issues in some sections get several examples while other issues get

no illustrative examples. I would have rather seen more even use of examples to

illustrate the issues. The approach of Barnthouse and Brown in Issue Paper 3

"Conceptual Model Development" of using two examples throughout the paper is

much preferred. Enough details about the examples can be provided so that reader

obtains more than 1-2 sentence understanding of the example. Of course, carried

E-143
K.A. Rose - Issue Paper 8 p.2

too far, this begins to sound like the case studies. Many mentions of different

examples, as used by Smith and Shugart, could be effective if better examples

were selected and more evenly used throughout the paper.

8. Synthesis.--A major criticism I have of the paper is the lack of synthesis. What

are the issues? The paper reads more like a somewhat ad-hoc listing of topics with

arbitrary use of examples. I think the paper contains most of the relevant

information on the topic. But the information is simply listed without much attempt

to synthesize the information. I would the use the criterion of how much more is

gained by me reading the Issue Paper versus the 5-10 major papers cited in the

Issue Paper. My conclusion with this version of the Issue Paper is that I do not

gain much. If this were a review paper submitted to a journal, I would request the

authors to synthesize the information. Also, there is too much "see so and so" in

the Issue Pap(~r. This is especially unproductive because quite a few of these "see

so and so" are references to entire books. The authors should summarize the

important information within the Issue Paper. After I finished reading the Issue

Paper, I could not succinctly list the major issues associated with uncertainty in

ecological risk assessments without careful rereading of the paper. For example,

the entire 3 paragraphs in the important section of "Ecosystem Characterization" is

devoted to the original definition of ecosystem by Tansely in 1935. What are the

issues with uncertainty in Ecosystem Characterization? No mention of uncertainty

in feedback loops or indirect effects affecting the predictions of risk, to name lust

two of the important topics.

8. Technical.--

(a) I am confused by the authors treatment of stochasticity. They define

stochasticity as the natural variation in a system (page 8-5). In the following

paragraph they imply that stochasticity is "bad" in that it can mask some

effects. The critical issue is how should natural stochasticity in the system

be included in an ecological risk assessment. If the system of interest

exhibits ± 5% fluctuations then a 10% effect is significant. If the system

exhibits ± 100% fluctuations, then is a 5% effect significant? Models are

increasingly including stochasticity. Deterministic model predictions will

without doubt show an effect; it is the magnitude of the effect relative to

the natural variability of the system that is important. There is much

confusion in the modelling literature about using Monte Carlo techniques to

simulate stochasticity versus the very same Monte Carlo techniques to

examine parameter uncertainty. The details of how these two are

implemented using Monte Carlo techniques can have major implications on

the predicted results. The authors only mention Twari and Hobbie's

stochastic differential equations; much has been done since then with most

effort devoted to including stochasticity in difference equation population

E-144
K.A. Rose - Issue Paper 8 p.3

and community models.

(b) The authors contrast simple and complex models by correctly pointing

out the increased information demands of complex models (e.g., page 8-18).

Just reading the Issue Paper would imply that simple models are better. The

authors fail to emphasize that simple models have a history of being grossly

in error when used outside the domain of the information upon which they

were estimated. Complex models, if configured reasonably with appropriate

feedbacks, etc., can perform better outside the domain of observations

better than simple models. As many risk assessments involve predictions

outside the domain of what has been observed, this feature of complex

models should be discussed.

(c) The authors fail to mention some important references. For example, on

the topic of model selection; EPA has published a series of Guidance

documents for different types of models. These are not mentioned in the

Issue Paper.

(d) There are other technical issues I would like to see addressed, but these

would be better dealt with in a subsequent version of the Issue Paper.

G-. Case studies.--For this Issue Paper, and the other Issue Papers, to be useful,

they need to be very tightly coordinated with the case studies. I personally believe

that the case studies will be more informative than the Issue Papers. If closely'

coordinated, the combination of Issue Papers and case studies could be extremely

useful. Without close coordination, .the reader will be faced with the almost

impossible task of cross-referencing between the case studies and the Issue

Papers.

E-145

Review by A. Frederick Holland

Comments Paper No.8: Uncertainty in Ecological Risk Assessment

8-1 Clarity of Purpose and Scope

The Introduction to Issue Paper 8 does not clearly and succinctly

define its goals or how these goals are connected to the

development of guidelines for ecological risk assessments. This

is critical information if EPA scientist will use the paper for

development of policy (i. e., guidelines for conduct of ecological

risk assessments). The authors should reorganize the

Introduction to ensure it accomplishes at least the following:

(1) defines what an uncertainty analysis is [the next to last

paragraph on page 8-6 is a good start on this], (2) discusses the

relationship between an uncertainty analysis and the

determination of ecological significance discussed in Issue Paper

2 - Ecological Significance [this topic also deserves a section

in this paper], (3) identifies sources of uncertainty (Le., lack

of knowledge, stochasticity, methods error/mistakes -- the first

paragraph of the Introduction is a start on this but needs to be

expanded - see discussions in Faber et ale 1992 and Suter et ale

1993 for additional details), and (4) relates the evaluation of

uncertainty to the steps in the ecological risk assessment

process including a discussion of the organization of the issue

paper.

8-2 Completeness of Coverage

As will be noted in the discussions below, I think the current

objectives of Issue Paper 8 (listed in last paragraph of page 8-

7) represent a major problem. This is because these objectives

do not lead to a synthesis of what we currently know about the

assessment of uncertainty in ecological risk assessments. The

current objectives also do not lead to recommendations of future

research activities that EPA should pursue related to assessment

of uncertainty in ecological risk assessments. The last two

sentences of the Introduction are particularly troubling -- "Our

purpose is not to present an exhaustive review of all sources of

uncertainty and methods for its assessment. Rather, we have

attempted to present some of the important aspects of uncertainty

as they relate to ecological risk assessment and the Framework,

while offering suggestions for dealing with the lack of

knowledge". Indeed, the authors did not provide comprehensive

coverage of the sUbject matter. More importantly, however, they

did not provide a summary of what is know about assessing

uncertainty in ecological risk assessment or which approaches,

in their opinion, are most applicable for which kinds (e. g. , single species, population, community, ecosystem) of assessments.

I think the major objective of Issue Paper 8 should be to

integrate and synthesize what is currently know about evaluation

E-147
of uncertainty in ecological risk assessments and to use this

synthesilS to: (1) define a generic process [or at least the steps

in a process] for determining the magnitude (relative or

quantitative) of uncertainty, (2) develop criteria for evaluating

when an uncertainty analysis is adequate or at least determine

when an analysis represents the best that can be done using

existing technology, and (3) makes recommendations for developml~nt of future technology and research. In short, I think

Issue Paper 8 should answer the following questions:

• What do we know about assessment of uncertainty ecological

risk assessments (i.e., development of a synthesis about the

topic - a review paper)?

• What types of uncertainty analyses have others accomplished

and when where the results from these uncertainty analyses

useful and reliable and when were they unacceptable (i.e.,

a evaluation of existing methods and approaches - part of

the synthesis)?

• What types of research and specific research "topics are

needed to resolve deficiency in uncertainty analyses?

The completeness of coverage for Section 2 (Problem Formation)

is partic::ularly weak. It provides information for only one type

of problE~m (i. e., ecosystem level impacts and risks) and one type

of modeling approach (i.e., ecosystem level). As discussed in

Issue Paper 2 (Section 3.2), ecological changes occur at all

levels of ecological organization (individual, population,

community, and ecosystem). In addition, single species

population level assessments are, in my opinion, the only ones

for which we presently have the empirical and theoretical basis

on which to base reliable risk assessments. Ecologists just do

not understand trophic dynamics and ecological processes well

enough for many ecosystems to predict and understand the

consequences of anthropogenic impacts except in very general

terms. Ecologists can not even agree on the appropriate

endpoint:; to measure for risk assessments at the community and

ecosystem levels. Therefore, assessment of uncer'tainty for

single species population level assessments probably deserves

more consideration than it is given in Issue Paper 8. Section

2-6 (Summary) should in my opinion be the introduction or

starting point for section 2 rather than the conclusion.

Additionally, the discussions in Sections 2.1 - 2.5 do not

adequately discuss the impacts of model structure, formulation,

system characterization, or implementation on the uncertainty of

predicticms. All these sections do is point out that

decisions/choices made during these phases of a risk assessment

affect outcomes. It is critical that the discussions in sections

2-1 to 2-5 provide examples of the effects different model structurl~s, formulations, and implementation have on uncertainty

E-148
for different types of risk assessments. Such examples would

provide the EPA scientists who will be responsible for

development of risk assessment guidelines with an understanding

of the consequences that decisions made during the problem

formulation phase have on assessment of risk and the associated

uncertainty. See 8-6 below for a discussion of how the range of

models used to evaluate the risks of power plant operations on

fisheries may represent an excellent case study for Issue Paper

8.

8-3 Clarity and Consistency of Terminology

If the audience for the series of issues papers is the EPA

scientists who will be responsible for development of Guidelines

of Ecological Risk Assessment then a glossary is probably not

needed. In general, the authors of Issue Paper 8 used accepted

terminology. There are, however, a few instances where jargon

(e.g., the use of the word "sizing" in the last paragraph on page

8-30 or "input mapping" in the first paragraph on page 8-32)

needs to be removed during the editing process or better

explained.

8-3 Current capabilities vs. Future Needs

The discussions in sections 3 (Analysis-phase Uncertainty) and

4 (Risk Characterization) not only do not provide complete

coverage of their sUbj ect areas (i. e., a synthesis in the context

discussed above), they also do not provide recommendations of

future needs. For 'example, no context for the manner in which

the severity of impact, reversibility of effects, duration and

timing of exposure, etc affect uncertainty in ecological risk

assessments is provided. A series of figures similar to Figure

1 belo~ would provide agency scientists responsible for

developing risk assessment guidelines with a set of heuristic

tools for identifying the classes of risk assessments when

reliable estimates of uncertainty are critical.

E-149
Figure 1. Degree of Reliability Required by Uncertainty Analysis

Case 1: Relationship to Severity of Impact

I Uncertainty I

High Low

Quantitative uncertainty Semi-quantitative uncertainty

High estimates desired estimates acceptable

Severity of

Semi-quantitative uncertainty Qualitative uncertainty estimates Impact estimates acceptable acceptable

Low

Case 2: Reversibility of Impact

Uncertainty

High Low

Semi-quantitative uncertainty Qualitative uncertainty

High estimates acceptable estimates acceptable

Reversibility of Impact Quantitative uncertainty Semi-quantitative

Low estimates desired uncertainty estimates

acceptable

8-3 Current Capabilities vs. Future Needs

Any assessment of the uncertainty in models used for a risk

assessment must answer the question "How reliable and credible

are analysis reSUlts?" (e.g., see Oreskes et al1994, Reckhowand

Chapra 1983, suter et al. 1987, Levins 1966 - I am sure there are

probably other relevant literature of which I am unaware on this

topic). Models are black boxes to many risk managers including

some of the EPA scientists who will be responsible.for developing

the guidedines document. As a result, a discussion of importance

of knowing the assumptions and limitations of models and examples

of the effects model assumptions have on the risk

characterization and estimates of uncertainty is critical to

understanding limitations and strengths of analysis results. In

addition, as Suter et al. (1993), and many others, have suggested

application of multiple models with different assumptions and

endpoints is a' reasonable approach for identifying and evaluating

uncertainties associated with various model s"tructures and

modeling approaches. In sections 3 and 4 the authors need to

expand discussions of the processes that can be used to verify,

E-lSO
validate, and calibrate models.

section 3.1 provides a very general description of the literature

on experimental design and the power of the test to reject the

null hypothesis. Unfortunately, this discussion is not

sUfficiently detailed for developing national policy (i. e. , guidelines) for risk assessments. For example, it does not

include a discussion or criteria for deciding when high power is

needed (e.g., when the potential for ecological significance is

high), and when it may be acceptable to use less powerful

sampling designs (see Figure 2 below). The discussion in

section 3 also needs to elaborate on the association between

power and ecological significance. In addition, the discussion

in section 3.1 does not provide any guidance for increasing the

power of the test (e.g., it does not include an evaluation of the

degree to which a covariate would improve the power or the change

in power that would be associated with use of a different test

metric). .

Figure 2. Decision matrix for evaluating the relationship between severity of impact, ecological significance

and the power of the test.

Ecological Significance

High Low

High power required Low power acceptable

High

Severity of

Very high power required Low power acceptable Impact Low

A important issue the authors need to address in Sections 3 and

4 is to define the steps in a· process tha;t can be used for

reducing uncertainty in the design of risk assessments. The

process that is developed must be compatible with and build upon

EPA's existing Data Quality Objectives Process (e.g~, see Boesch

et ale 1990 for a discussion of how to design a monitoring

program to reduce uncertainty and increase power or Downing 1979

for some of the problems associated with sampling invertebrate

populations as it relates to increased power).. In addition, the

authors should develop criteria that can be used for assessing

when the power of an assessment is inadequate since high power

and high costs are positively correlated. Ultimately, the "real"

question risk assessors must address is "How much power is

adequate given the available dollars?" Some simple discussions

about how cumulative frequency distributions and cumulative

probability functions such as those on pages 45-46 of Suter et

ale 1993 may help with these discussion.

E-151
The conclusion/guidance on page 8-23, end of 1~ paragraph, that

"safe ll~vel from simple studies must be viewed with some

suspicion" needs a better explanation and additional details

including a review of the literature. For example in a classic

review, Levin et ale (1984) describe the broad range of

sensitivity of biota to toxicants that characterize natural

ecosystems and suggest that assessments of risk based on acute

bioassays of relatively few species are likely to provide

inadequate assessments of risk. The question, however, is how

many tests are required, of what type and for what species. I

am unfamiliar with the toxicology literature, but I am sure that

this qUE~stion has been addressed. This discussion must be

expanded.

The treatment of the uncertainties associated with extrapolations

in section 3 would greatly benefit from use of examples such as

that prl:sented in Suter et ale 1993 (pages 239-246). Such

examples, could also be derived for extrapolations from one

population to another (e.g., Barnthouse et ale 1990) on one

ecosystem to another (Sloof et ale 1986). In my opinion, it would

be sUfficient to summarize/synthesize what these other authors

have accomplished as part of Issue Paper 8.

8-5 Relatic)nship to EPA's Framework for Ecological Risk Assessment

I found the discussion of uncertainty in the Framework document

so general that it provided little insight into how to estimate

the magnitude of uncertainty or determine if it was in acceptable

ranges. The Framework document is so general that it is no more

valuable to the risk assessor than "common sense". Issue Paper

8 expands upon the categories of uncertainty defined in the

Framework document; however, Issue Paper 8 does not elaborate

upon the relationship between the weight of the evidence

discussions in the Framework document and the uncertainty

analysis process. It also does not tell a risk assessor when an

assessment of uncertainty is critical to interpretation of

assessment results, how to estimate uncertainty, and what

criteria. should be used for determining if uncertainty is

concorda.nt with conclusions.

8-6 Examples

The authors of Issue Paper 8 reference some of the relevant

literature as examples. Unfortunately, the examples they

reference are biased toward ecosystem-level assessments of

terrestrial systems and do not represent a cross section of

system or assessment types. The authors also do not use

examples/case studies to demonstrate the value of uncertainty

analysis to the environmental decision making process. Issue

Paper 8 would benefit from inclusion of examples of estimating

uncertai.nty in ecological risk assessments for aquatic ecosystems

E-152
(e.g., Cirone and Pastorak 1993) as well as organism and

population level assessments (e. g., Barnthollse et al 1988).

Suter et ale (1993) provide many additional examples that could

be summarized and presented as part of Issue Paper 8.

In, addition, the many different types of models that have been

used to assess the risks of power plant operations on fisheries.

This problem may provide a good case study for describing the

effects decisions made during problem formulation phase have on

results and reliability of results. Using available data from

the many 316 Demonstrations that have been conducted for power

plants, it should be possible to construct a table that contrasts

estimates of entrainment losses and uncertainty in those

estimates for several fish populations each with different life

histories. Model structures in the case study would range from

the simple formulations of Horst (1975) and Goqdyear (1978) to

the more complex formulations of Boreman et ale (1981) to the

very complex formulations of Hackney et al (1980) and Christensen

et ale (1977) to the system level formulations of Rago (1984).

Swartzman et al. (1978) provides a partial review of these

models. Power plant 316 Demonstrations have been conducted for

many different aquatic environments (river, lake, estuary,

coastal ocean).

Other examples that should be included in Issue Paper 8 include:

the impact of life history/space/time interactions on model

predictions (e.g., Hastings and Higgins 1994) and the impact of

life history on population assessments (e.g., May 1974). For

example section 4.2 '. 1 would benefit from additional details and

examples from Rose et ale (1991). .

Cross-cutting Issues

C-1 Terminology

There app~ars to be a problem with the use and interpretation of

the term "Ecological Risk Assessment". Some of the issue papers

appear to focus much of their discussion on ecosystem level

impacts/risks where other papers discuss risks at multiple levels

of organization. I think the term ecological risk assessment

needs to be clearly defined in a forward/ introduction to document

containing the series of issue papers and clearly applied

throughout the papers. Page 2 of the Framework document provides

a reasonable definition of "Ecological Risk Assessment".

Of particular importance is the definition of how ecological risk

assessment differs from ecological impact assessment as defined

under NEPA. Suter et ale (1993) state "The most important

feature distinguishing risk assessment, as discussed in this

book, from impact assessment is the emphasis in risk assessment

on characterizing and quantifying uncertainty." This quote

requires some discussion. More importantly, if this quote is

E-153
valid/true, Issue Paper 8: uncertainty in Risk Assessment becomes

a particularly important paper that may require sUbstantial

revision to address all the relevant issues raised by this quote

(e.g., the existing general discussion of uncertainty associated

with extrapolation may need to be expanded to include examples

of the consequences of extrapolations).

C-2 Population Level Risk Assessments

As Lev Ginzburg has discussed in his comments, single species

population level risk assessments probably represent the highest

level of organization at which predictive assessments can be

conducted with in degree of reliability and creditability. The

basic problem at higher levels of organizations ecosystems are

very complex and ecological theory has not even develop generally

accepted endpoints.

C-3 Need for Baseline Information on the status and Trends of

Ecological Systems

A conclusion that can be inferred from many of the Issue Papers

is that baseline information on the status and trends of natural

ecosystems is critical information for assessment of ecological

risks. status and trends information would be especially useful

for determinations of ecological significance (Issue Paper 1) and

estimation of uncertainty (Issue Paper 8). None of the issue

papers, however, recommend: (1) the spatial scale at which

baseline information should be collected (e.g., watershed,

regional, national) 'and what approaches should be used to insure

the data that are collected by monitoring programs like EMAP are

"represEtntative" and not biased by sampling at sites where data

are easy to collect, (2) what parameters, or type of parameters,

should Joe measured by status and trends monitoring programs

(e.g., should status and trends information be collected for all

levels of organization or just some, should exposure measurements

be included), or (3) the most appropriate temporal scale for

collecti.ng status and trends information for it to useful for

ecological risk assessments (e. g., are samples collected once per

year during a critical period adequate or are more frequent

collecti.ons required). All of the Issue Papers need to address

the above questions in their text. This is particularly

important since the National Monitoring Act has recently been

passed and EPA and NOAA has been charged with answering these

questions as part of this act.

E-154
References

Barnthousel L.W.; Suter, G. W.; Rosen, A.E. 1988. Analysis of

impingement impacts on Hudson River fish populations. American

Fisheries Society Monograph 4:182-190.

Barnthouse, L.W.; Suter, G. W.; Rosen, A.E. 1990. Risks of toxic

contaminants to exploited fish populations; Influence of life

history, data uncertainty, and exploitation intensity.

Environmental Toxicology and Chemistry 9: 297-311.

Boesch,· D. F. ; . Schubel, J.R.; Berstein, B. B.; Eichbaum, W. M. ;

Barber, W.; Hirsh, A.; Holland, A.F.; Johnson, K.S.; O'Connor,

D.J.; Speer, L•.; Wiersma, G.B. 1990. Managing Troubled Waters:

The Role of Marine Environmental Monitoring, National Academy

Press, Washington, DC.

Boreman, J.C.; Goodyear, C.P.; Christensen, S.W. (1981). An

empirical methodology for estimating for estimating entrainment

losses at power plants sited on estuaries. Trans. Am. Fish. Soc.

110: 253-260.

Christensen, S.W.; Matthews, C.P.; Clark, A.G. 1977. Development

of a stock-progeny model for assessing power plant effects on

fish populations. pgs 196-226. In: Assessing the Impacts of

Power-plant-induced Mortality on Fish Populations, W. Van Winkle

(ed). Pergamon, NY.

cirone, P.A.; Pastorak, R.A. (1993). Ecological risk assessment

case study: Commence Bay tidelands assessment. In: A Review of

Ecological Assessment Case Studies, EPA/630/R-92/005.

Downing,J.A. 1979. Aggregation, transformation, and the design

of benthic monitoring programs. J. Fish. Res. Bd. Can. 36: 1454-

1463.

Goodyear.,C.P. 1978. Entrainment impact estimates using the

'equivalent adult formulation. u.S. Fish and Wildlife Service,

Biological Services Program, Washington DC, Report No. FWS/OBS78/65.

Hackney, P.A.; McDonaugh, D. L.; De Angelis, D.L.; Cochran, M.E.

1980. A partial differential equation model of fish population

dynamics and its application in impingement impact analysis.

EPA/600/780-068 and TVA EDT-101, March 1980, 52 p.

Hastings, A.; Higgins, K. 1994. Persistence of transients in

spatially structured ecological models. Science 263: 1133-1136.

Horst,T.J. 1975. The assessment of impact due to entrainment of

ichthyoplankton. pgs 107-118. In: Fisheries and Energy

E-155
Production: A symposium, S.B. Salia (ed), D.C. Heath, Lexington,

MA.

Levin, S.A. et ale 1984. Perspectives in ecotoxicology.

Environmental Management 8: 375-442.

May, R.M. 1974. Biological populations

generations: stable points, stable cycles,

186: 645-·647.

and nonoverlapping

and chaos. Science

Oreskes, N; Shrader-Frechette, K; Belitz, K. 1994. Verification,

validatic1n, and confirmation of numerical models in the earth

sciences. science 263: 641-646.

Rago, P.J'. 1984. Production foregone: an alternative method for

assessin9 the consequences of fish entrainment and impingement

losses a1:. power plants and other water intakes. Ecol. Model.

24: 79-11J,.

Reckhow K. H.; Chapra, S.C. 1983. Confirmation of water quality

models. Ecological Modeling 20: 113-133.

Sloof, W.; van Oers, J.A.M.; de Zwart, D. 1986. Margin of

uncertairlty in ecotoxicological hazard assessment. Environmental

Toxicolo9Y and Chemistry 5:841-852.

suter, G.W.; Barnthouse, L.W.; O'Neill, R.V. 1987. Treatment of

risk in environmental impact assessment. Environmental Management

11: 295-303. .

suter, G.W.; Barnthouse, L.W.; Bartell, S.M.; Mill, T.; Mackay,

D.; Paterson, S. 1993. Ecological Risk Assessment. Lewis

PUblishers, London.

SwartzmaIl, G.L.; Deriso, R.B.; C. Cowan. 1978. comparison of

simulation models used in assessing the effects of power- plantinduced mortality on fish populations. NUREG/CR-0474/UW-NRC10/RE. Cc)llege of Fisheries, University of Washington, Seattle,

WA.

E-156
Risk Integration Methods

Workgroup Leader:

General Reviewer:

General Reviewer:

Dr. John Bascietto

Dept. of Energy

Dr. Peter Van Voris

Battelle-Pacific Northwest Laboratories

Dr. John P. Giesy

Michigan State University

E-157

Pre-M.eetiD& Comments Submitwd 10 Venar, lDc. On BehaU of U.S. EPA Risk A.ssc55maat

Forum - July 29, 1994.

RISK INTEGRATION ISSUE PAPER

PEER REVIEWER: John Bascietto

U.S. Department of Energy

Washington, D.C.

1. p. 9-5, 1: The definition of risk characterization referenced to AllIe, 1992 states that it is a

process which renders the relevant information "comprehensible to a divemty of users.It While it

certainly should do thi3, the use of risk integration, as the term is used in the Framework (Lc., as

the first step in risk estimation, is clearly focused on the risk assessors and risk managem. While

this is not contradictory to the AllIe definition, it is pcrhap5 a point for clarification in the issue

paper.

2. p. 9-5, 1: The first paragraph of the Introduction discusses the intent of this paper, but flows

directly to issues discussed not in this paper, but in the Framework (Le., the exposure profile and

stressor-rC5ponae profile). A more crisp break between the issues in each document

would help to set the stage in a less confusing way.

3. p. 9-8, 3: The review of the initial stages of risk assessment described by the Framework, f~ll a

little flat. 1 did not get a sense that this review was performed for the purpose of introducing risk

integration. Consider providing more commentary on the salient risk: integration issues posed by

these initial Framework sections. which the authors iDel warrant particular attention by the

readers (e.g., see next Comment Nos. 4, 5, and 6 below). I would rather see a discussion of how

the risk integration approach will flow from the initial stages of the risk assessment. Is there a

systematic thought process one uses to proceed from Analysis to Risk Estimation, for example?

4. P 9-8, 3.1: the discussion focuses narrowly on the science issues. The authors should consider

that the Problem Formulation must also provide a absolutely essential link to the regulatory and

policy context of the risk assessment. The resolution of certain regulatory and policy issues may

provide valuable direction later, as to the acceptability ofsome the potential risk integration

methods. These issues may be touched upon in Program Office guidance documents.

5. P 9-8, 3.1: CoDliider providing an example of how "scale. level of resolution, and available

information" assist in selecting risk integration tools.

6. P. 9-9. 3.1: Two of the iInportant activities of the Problem Formulation phase (according to the

Framework) are: 1) development of a conceptual model; and 2) selection of endpoints. Although

these 8Ctiviti~ occur prior to risk integration, what are the salient integration-related iNUe5 to be

considered by the risk assessor at these initial stages in the proce&S?

7. P 9-9, 3.2: Would it be more appropriate to state that "the risk integration technique must be

compatible with the data for effects and exposure" instead of the CUlTent construction: "effects

and exposure data need to be compatIble with the risk integration"); and if not, what are the

important i&Sucs and circumstances which make the current construction appropriate?

E-159
8. P 9-10) 4.1.1: In the discussion of SingJe~ValueComparisons the term "applicatioJIl factor" is

used to dc:&Cn'be an adjustment that made to the toxicity benchmark. There may be some

confusion result from this term., as it is variously called "safety factor" and "uncertainty factor" by

various EPA PrlJgraIn Offices. and other risk assessment guidelines. The Workshop participants

could provide guidance to the authors OIl this and the other issue papers on the use of the term.

9. P 9-10, 4.1.1: It is not always true that assessments employing the quotient method (OM)

"assume that eJq;JOSure concentrations are invariant in space or time." While this is a certainly a

limitation of the QM and a common criticism, moat assessments I been involved with readily

acknowledge the limitation, and do not assume iDvarianc:e. Nevertheless, the substance of the

authors' point is: well taken and obviously mU&t be acknowledged.

10. P 9-10 and 9-11, 4.1.1: A very brief explanation of the demonstration by Breck et al (1988)

would help clarify the point on implications ofspatial-temporal variability in exposure toxic effects

for fish populaHons exposed to aluminum.

11. p 9-11, 4.1.1: Again, I disagree that quotient method assessments routinely a5/J\lme that effects

data are 5uita.bII~ for extrapolating directly to the field (see above comment No.9 on uBe of

concentration data in QM). EPA QM assessments I\re been involved in routinely acknowledge

the weaknesses ~iated with this procedure. Neverthele5l5, the substantive point is well taken.

12. p. 9-12, 4.1.2: The authors state that in joint distributions calculations. the risk is the

probability that the exposure concentrations and the concentrations correlated with measurable

effects represent the same underlying statistical distribution, and that risk is the probability that

the two distribu,tions overlap perfectly. It would be velY useful to the reader to have this

graphically illustrated; also consider providing any examples possible imperfect ovedap5, their

interpretation and implications.for risk estimation, and the associated graphics. The same

comment pertains to the discussion of the risk as the degree of overlap of a distribution of

Clq)Osure concentrations with a benchmark point estimate.

13. p. 9-13, 9-14 land 9-154.1.3 and 4.1.4: Consider providing graphic illustrations/ examples of

Regression analysis and Fuzzy Sets. Also consider prO\liding a brief discussion of the implications

of use for rcgre:s:sion models (When? where?) and their limitations in ecological ri5k assessments;

N.H.- there is la specific discus5ion in the special model discussions, but the authm-s should

provide lOme generalized guidance on regression model analysis at poiltl

14. P 9-15, 4.1.4: The discussion of Fuzzy Sets and Fuzzy Arithmetic could benefit by a brief

discussion of how the authors believe this approach would be communicated to decision-makers

an the public.

15. P 9-18, 4.1.6: The authors suggest that the parameters and coefficients in the models of

Individuals may have little or no meaningful interpretative value that could help a.'S5e:5lS0rs and risk

managers understand relationships or develop and evaluate mitigation or remediation altematives.

This is no small point, since in programs like Superfund and RCRA (which have driven much of

the efforts on I~Iogical risk assessment guideline development), project and risk managers are

likely not to focus on (or even perform) studies which do not tell them anything about

remediation. 1lberefore, this line of discussion needs to more fully fleshed out, particularly in the

guidelines development process.

E-160
16. p. 9-19, 4.2: There is a vel)' interesting commentary on the traditional biologica1level-oforganization terminology, which the authors state ha.-. become "ecological shorthand". which can

act to suppress "conceptually powerful alternative approaches to description, 5tudy, and

understanding of Nature." The reader would certainly have appreciated more iDsight into what

(he authol'S' feel are "Nature's c:sscntials", i.e., that which is being glossed-over by the use of

"ecological shorthand"

17. p.9-20 and 9-21, 4.22: provide definition or explanation of the term "ecologically relevant

population", and provide consistency with the term "ecologically important population". It would

also help if the authors could provide some preliminary thoughts, specifically as how 8lI8CSSOI'S

should go about "rigorously and meaningfully" defining the populations which are the subjects of

risk assessments.

18. P 9-21, 4.2.2: The authors make a very good point regarding the limitation on effective

application of population modelling in ecological risk aasessment, due to difficulties in deriving

disturbance-response functions for U5e in altering model parameter values in relation to the

degree of disturbance. A diicussion and perhaps graphic illU6trating how such models are

nevertheless used would be particularly beneficial here.

19. P 9-41, 4.6; The endpoint selection criteria discussion seemed more appropriate for the

Problem Formulation review section up front (see comments Nos. 3 & 4 above). Discussion in

Section ~6 could focm more on how natural variability is handled in specific risk integration

methodology.

20. p 9-43, 4.8: After the resistance and resilience have been evaluated, how should they be

handled in specific risk integration methodology?

21. p 9-45,9-46 and 9-47,4.10: As a general comment, there needs to be a clearer differentiation

between the di5cussioDJ of recovery to pre-disturbance baseline state, as opposed to recc;JYery

between "healthy", post-disturbance state.

22. P 9.53, 53: The authors have associated the term "Weight. of- evidence" with the balancing

of risks with the other dynamic factors such as worker health and safety, cost-benefit analysis,

social and political considerations ) which is essentially a risk management, not risk assessment

function. EPA has used what it has called the "weight-of-evidencc" approach to characterizing

(i.e., risk integration in this con~) ecological risks, particularly risks to nOil-target organisms

resulting from applications of pesticides, which could be termed a semi-quantitative risk

asSe55ment methodology. What, if anything, should be presented, in tenns of this apparent risk

integration methodology?

E-161

Risk Assessment Forum

Ecological Risk Assessment

Issue Paper

Peer Review Workshop

Pre-Meeting Comments

Risk Integration Methods - by

Peter Van Voris

1.0 Introduction: • Page 9-5

The Introduction addresses those items which the Framework document

covers as well as those issues addressed in this particular issue paper. It states

that the Framework Report identifies several approaches that can be used to

characterize ecological risk and then goes on to list three critical elements.

However, it does not state ,if the following factors are addressed or considered:

(1) whether or not comparisons can be made between cumulative effects of single

or multiple stressors, (2) it does not state whether or not the system conditions

prior to or during the stress event are important factors, (3) whether or not

spatial/temporal factors important to the system at risk are considered in the

integration of risk, (4) whether or not system susceptibility or adaptation or

sequestration of a stressor are accounted for in the process of integration of risk,

and (5) whether or not the current trajectory of the system and its components

are considered within the framework.

3.1 Problem Formulation Page 9-8

The authors state that the scope of the risk to be characterized and the level

of biological organization population, community, landscape, and larger must be

identified but do not provide an example of how one can effectively limit the

assessment to a given level of ecological organization. Additionally, the status or

condition of the system (system state variables) are not mentioned as important to

defining the problem; only the type of ecological stressors are provided as

examples.

Reviewed by pvv

E-163
The last paragraph of 9-8 allude to "evaluation of the decision-makers

requirements to (1) discuss how these requirements further constrain the studies"

- This makes it sound as if a complete and full assessment of the risks can be

sublimated by the decision-maker. This reviewer takes this to mean that the

decision maker can control the out come of (1) risk characterization; (2) risk

assessment and (3) risk management in an a prior way.

4.0 Risk Characterization page 9-10

The authors have provided a good assessment of the Single-Value

Comparison quotient methods and its limitations. They have clearly identified

the assumptions made and they have assess the validity of making comparisons of

ratio of exposure concentration to a toxicity benchmark that is based on toxic

chemicals. They have also identified the issue of suitability of extrapolating the

tox data derived on single species or populations to field conditions. - This

reviewer would find it useful if further discuss could be provided on the

reliability of the values referenced in table 3 and the Suter (1992) "empirical

validity" reference. This reviewer finds it valuable that this paper places in

prospective the value of the single quotient method - Le., for "screening purposes

or assessing comparative' effects of natural or human caused disturbances".

Additionally, the authors do an excellent job of reminding the reader that' the

quotient method is difficult if not impossible to integrate with any assessment

endpoint because the quotient does not share the same distribution as

probabilities.

4.1.2 Joint Distribution - page 9-11

The discussion of joint distributions is well done and uses an excellent

example to drive home a point in paragraph two; however, it again shows the

limits of this approach in that in joint distributions the limits are placed on

detennining the probability that the exposure concentrations distribution overlap

with the measurable effects distribution. This discussion points out that this

method allows one to address the spatial and temporal patterns of the stressor but

it does not address how the spatial and temporal patterns of the target organism,

population, community, system, or landscape play in the risk characterization

processes.

Reviewed by pvv

E-l64
4.1.4 Fuzzy Sets and Fuzzy Arithmetics

It is not clear to this reviewer where this section is leading - it needs a

practical example of the use of this approach to risk characterization.

4.1.5 Extreme Events Analysis

This section starts off well but needs an example to carry the relevance of

EEA for empirical methods of risk characterization. An example of the value of

an extreme event such as the risk of nuclear mishaps or comet/Jupiter collision

and its effects would be worth while.

4.1.6. Advantages and Disadvantages

Is this section a compilation of the value and limitation discussions that

have been previously provided. I was not expecting this section after the

discussion of the pros and cons of each methods.

In paragraph one of Advantages and Disadvantagesthe discussion seems to

be limited to single chemical events that rely on the standard factors such as

bioaccumulation or organics - and ignore factors such as metabolism or such

compounds as well as <sequestration of a stressor to avoid exposure.

Compensatory mechanisms are not a factor or are they.

Finally, this reviewer believes that a more effective way of showing the

Advantages and Disadvantages would be to take the same set of examples through

each model approach and finish with a table showing how each approach

characterized the risk

4.2 Process Models - page 9-18

The general presentation of the Process Models se~tion is much stronger

and is very well written. The authors do a good job of identifying the fact that

these types of models represent "a priori sets of hypotheses about causal

mechanisms operating in the system" - This reviewer thinks that the authors

should expand on this point - identifying the limitation with examples of

modeling the process based on one hypothesis versus another.

Reviewed by pvv

E-165
The authors predict that process models will see increasing use in risk

characterization based on the shear number of assessments that win need to be

perfonned. They state that in some instances using process models will allow the

analyst to avoid the experimental evaluation of the disturbance and models are

the "only" alternative. This reviewer agrees but - other model systems can be

used to test a subset of the disturbance and the use of "only" might be a little

strong.

The discussion of the levels of ecological organization is important and the

reader should be advised that this issue paper will use this approach to segregate

the various m.odels that have been used for risk assessments.

4.2.1 Models ofIndividuals

This issue paper reviews IBMs and this reviewer believes the authors have

wrongfully included the FORET model in this class of models. The gap models

are clearly based on individual dynamics but the output parameters are for

individuals, populations and community properties. Should this type of model be

considered to be a bridging type model.

4.2.2 Population Models

The authors have done an excellent job of reviewing population type

models; however, should this section be subdivided to separate the population

type models from the bioenergetics approach. Additionally, if there are

examples of each that have been used for "ecological risk characterization" this

reviewer would like to see how they have been used.

4.2.3. Cornn:lunity Models

The authors have provided a good general review of the community

concept and the associated models and suggest that these models offer some

potential for assessment of food web impacts. More examples of the potential

applications of community models are needed in this section.

4.2.4 Ecosystem Models

This reviewer is pleased that the authors choose to address up front the

issue of "ecosystems" and the value of feedback mechanisms in determining

system functional integrity as well as system recovery. However. they almost

Reviewed by PVV

E-166
ca,sually suggest that "advances in ecosystem understanding should be considered

carefully in the development of ecosystem-level endpoints for risk analysis" - It

seems as if we have moved from risk characterization to risk analysis without a

true transition. Additionally, the authors could expand the types of citations such

that they cover the various types of ecosystems - lakes vs. streams vs. rivers and

other types of examples for terrestrial ecosystems.

4.2.5 Landscape and Regional Models

The authors have done a reasonable job ofreviewing the ecological models

that have been used in landscape and regional risk assessment; however, they have

overlooked several recent articles that have been published in the Int. J.

Geographical Information Systems.

A copy of Van Voris et aI., 1993 is attached to this review for the authors

consideration. This article is entitled "TERRA-Vision - the integration of

scientific analysis into the decision-making process" - Here TERRA stands for

Terrestrial Environmental Recourse Risk Assessment - Visioning System - and it

uses a FORET forest growth gap model over large geographic areas (one

latitude by one longitude) using a Cray computer as the processor coupling the

data output to a GIS. This system was used to address concerns with global

climate change over a variety of geographical areas and support decision makers

with a way to embed scientific analysis into the decision-making process.

4.2.6 Aggregation and Disaggregation

The authors might better address this issue by attacking the problem from

the angle of scaling modeling output - articles written by Ken Perez from EPA

Narragansett should be sought to support this area.

4.2.7. Implementation

I'm not sure why this section is needed - if we had parallel structure then

we would have Advantages and Disadvantages of Process Models and the

implementation issues could be address under this section.

Reviewed by pvv

E-167
4.3 Physical and Experimental Models - 9-34

I would have hoped for a more balanced presentation by the authors for

the reader. After having spent approximately 30 pages on mathematical and

statistical models and how to apply these to risk assessment, I would have hoped

for something more than a short paragraphs dealing with "Cosms" and

approximately a page dealing with Field-Scale Experiments.· Additionally, the

citations are limited and for the most part are quite dated. Strongly suggest that

this section be expanded to add.ress the application of both physical and

experimental models and how to couple these systems with mathematical models

as well as the advantages and disadvantages of Cosms and Field-Scale

Experiments.

4.4 Example Application

The chapter headings don't appear to be logical - 4.4.1 PhosphorousLoading Models - 4.4.2 Toxicity Risk Models in Ecosystem Context - then 4.5

jumps to Uncertainties. The authors might want to reconsider the structure of

the issue pape:r and its organization.

4.5 Uncertainties

Again the structure and organization of the issue paper seems to have

broken down - I would have organized the paper to have this section in the

process model section.

4.5.3 Model Validation

I would have included "Cosm" validation in this section - see Van Voris, P.,

D. A. Tolle, M. R Arthur and J. Chesson. 1983. Terrestrial Microcosms:

Validation, Applications, and Cost-Benefit Analysis. In: Multispecies Toxicity

Tests, ed. J. Cairus, Jr.

4.6 through 4.10

Reviewed by PVV

E-168
These sections seem to be a compilation of a variety items that could be

reorganized into other sections. Also, more examples and demonstrations are

needed throughout the sections.

5.0 Risk Summary

As stated previously, the organization of the issue paper needs to be

reconsidered - sOII\e of the early sections could be moved into this section.

;'t

Reviewed by PVV

E-169

Risk Assessment Forum

Ecological Risk Assessment Issue Paper

Peer Review Workshop

Pre-meeting comments

Risk Integration Methods

By

John P. Giesy

August 10, 1994

Genera1 Areas for COnsideration:

G-1. Clarity of purpose and scope.

The paper is well organized and clearly written.

G-2. CoJIPleteness of coverage.

The paper is very comprehensive.

G-3. Clarity and consistency of terllinology.

The terminology is clear and consistent

G-4. current capabilities vs. future needs.

There is little information on what additional technologies are

needed or how they would be used. There is some coverage of how

current technologies would be used.

G-5. Relationship to EPA's frmaework for ecolOCJical risk

assessaent.

The document is not organized to address particular sections of the

framework for risk assessment directly.

G-6. BxaJIP1SS

There are a few examples but there could be more concrete examples.

Also, tables or figures would be good to illustrate concepts.

Questions Relevant to Risk Inteqration Methods Chapter:

9-1. Physical and experiJIental lIlOdels are included as risk

integration tools. I:s this correct, or should these :aodels be

considered as analysis phase aethods?

Yes. I feel that this is correct. Both types of models need to be

presented and discussec

E-171
9-2. What .!xawples can be provided regarding the application of

fUZzy set theory to ecological risk at;SesSllell1:s?

Here some numerical examples would be helpful. I suggest that some

figures would also be helpful.

9-3. How (if at all) should the paper be changed 'to better diffeJ~entiatecurrent capabilities fro. future research needs?

See specifi.c comments on each section.

9-5. What c:hanges, if any, should be .me in the balance between

'the v~arious sections of 'the report.

See specifi.c comments on specific sections of the paper.

CoJoMmts orl specific sections of the discussion chapter.

General:

1) The chapter, as currently written, focuses on aquatic systems.

Additi.onal information and examples could be presented on

terres:trial systems.

2) I suggest that more information on scaling of the various

models be added to the discussion.

1. :Introduction:

1) The i.ntroduction should inclUde as discussion of the

ecological uncertainty principle, in the context that the framework

will be improved incrementally by better and better simUlation

models or improved quantity and quality of information on the

parameters used in simulation models.

... Risk Characterization

".1 EJIpiri.cal JIOdels

1) All ccmceptualizations of ecosystems are simplifications of

the Ureal world" and their responses to stressors are

simplificat:ions. Even if these simplifications are made in such a

manner to ,explain most of the variation in an ecosystem, it is

unlikely that accurate predictions can be made in a generalized

manner. This must be recognized as a basic limitation of models.

Since there are mUltiple parameters that have incremental effects

on the responses of systems to stressors it will remain impossible

to predict~, a priori, effects that have not been. observed

previously with any certainty.

2) The mt::>dels used in the risk assessment process should be

structured in such a way that they are protective of ecosystem

E-l72
function, but need not be predictive. The only way to do this is

to disaggregate the system ±nto consti~uent elements. I suggest

that these elements are, in fact species. If one uses a range of

species of known general sensitiTities to stressors it is likely

possible to protect ecosystem functions with a high degree of

certainty, but will be impossible to predict the actual trajectory

that a stressed ecosystem will take.

3) I suggest that probableistic models be used in this context.

I suggest that simul'ation models will be more useful for the

exposure portion of the risk function than the hazard portion.

4) The approach suggested by the EPA Framework will work with

individual chemical stressors, but currently does not have the

sophistication to deal with mUltiple chemical stressors or physical

stressors.

5) The structure of neither the EPA framework nor the method

suggested in the position paper will effectively deal with

community-, ecosystem- or landscape-scale perturbations. An

example of the use of the framework with incremental habitat loss

would be useful. Estimation of the duration and intensity of

exposure can be effectively estimated by some simulation models.

This information can be compared to a probability distribution of

effects on individual species. A great deal about ecosystem

function can be predicted by an expert system from the probability

of effects on different species without the use of integrating

statistical or simUlation models at the community or landscapelevels of organization. This may allow one to predict most

probable safe concentrations in the ecosystem, but will not allow

for effective prediction of effects.

6) Effects on top predators will be most difficult to predict

from the current framework.

7) MUlti-generational studies of effects of chronic exposure to

chemical stressors under ecologically relevant conditions should be

included in the risk assessment process.

8) The recommendations of the Aquatic Effects Dialogue Group on

the risk integration methodologies should be included in the

current document.

9) This section needs a discussion of the theoretical limits of

uncertainties of models.

4.1.1 Single-value coaparisons

1) Do not use arbitrary safety factors in the risk assessment

process. These should be added in the risJe integration section of

the process.

2) P. 9-11 Para. 2: The authors state that the empirically

derived application factors given in Table 3 were empirically

E-173
derived. More discussion of' these factors and how they were

derived is needed.

3) P.9-11 Para 3: I agree that these types of quotients should

not be considered to be quantitative risk assessments. Do not use

any single value quotient methods in ecological risk assessments

without considering the· types and extents of adverse effects to be

incurred.

. . 4) I agrE!e that most models are empirical. For this reason, most

risk assessments of chemical stressors will need to rely, at least

in part, on historical information on similar compounds or with

similar chemical and physical properties.

5) Secti()n 4.1.1 need more examples. These should include

uncertainties introduced by pulsed exposures, mUltiple stressors

and transf()rmation products of stressors.

6) secti()n 4.1.1 needs more discussion of uncertainty factors and

how they will be integrated into the risk integration

methodologies. A discussion of error analysis and how it could be

used in the risk assessment process would augment this section.

4.1.2 Joint Distributions

1) Better models or toxic modes of action will be needed if the

predictive power for multiple chemical stressors is to be develop.

2) I suggest that probableistic models be used in this context.

I suggest that simulation _models 'will be more useful. for the

exposure portion of the risk function than the hazard portion.

3) P. 9-J.1 Para 4. I endorse the suggestion that there is a need

for ,more realistic assessments by the use of probability

distributions (see AEDG document, US EPA).

4) P. 9-12 Par. 4 L. 2 I disagree. The information can not and

should not be random, but rather. directed based on previous

knowledge of the system or stressor of interest. It should be

endeavored to include a range of uncertainties, such as critical

species or life stage. Caution, should be taken so that the

complete range of possibilities is included in the analysis such

that the probabilities derived are not a function of the values

chosen as !;tarting values in the analysis.

NOTE: Jrurthermore, when these probabilities are calculated the

endpoints c:::hosen must be consistent and duration and intensity of

exposure to the stressor included.

NOTE: These types of probableistic models will need to specify

the appropriate target receptor (organism of sub-organismal or even

E-174
a function) and be coupled to simple factors that will affect the

receptor and thus it's response to the stressor. This should "be

done in a tiered approach (see AEDG report from EPA).

4.1.3 Reqression Analyses: .

1) Regression models were noted, but what about the use of

quantitative structure Activity (QSAR) effect models? More on this

topic, including a state of the science should be added to the

chapter.

2) P. 9-13, Para 3: Add that this can include compounds (see

reference by Giesy and Graney, 1989).

Giesy, J. P. and R. L. Graney. 1989.

intercomparisons of acute

Hydrobiologia 188/189:21-60.

4.1.4 Fuzzy sets and Fuzzy Aritblletic

Recent developments in and

and chronic bioassays.

1) The section on Fuzzy logic is good, but could be expanded.

Add a section on how an expert system could be built into the risk

assessment process, especially in conjunction with fuzzy logic.

2) P. 9-15: Need to add an example of how fuzzy logic could be

incorporated into the ecological risk assessment process.

3) Need to add a section on the allowable or most probable ranges

to bound regressions of the fUZZy logic so that fUZZy but not

"crazy" predictions are made.

4) Some figures would make this section more demonstrative.

4.1.5 Extreme event analysis:

1) This section is excellent. I agree with everything stated in

the section.

4.2 Process (Mechanistic) .adels:

1) I would add a table to this section in which are listed a

number of possible mechanistic process models with an indication of

when they should be used and the degree of confidence for each

model.

4.2.1 MOdels of Individuals

1) A limitation of mechanistic models of individuals is the

existence of alternative pathways and pathway switching that goes

on in organisms as an adaptive response to environmental stressors~

Need to have better models for scope for growth and other

E-175
relationships that can be either continuous or discontinuous.

2) P. 9,-24 suggest that any models used in integrating

ecological risk assessments will be combinations of both energetics

and popula1:ion models.

3) It will be more likely that models will allow prediction of

population--Ievel effects for effects on individuals or populations.

The most sensitive endpoints should be specified. These are

probably growth and reproduction. Sensitive species should be used

in screening tests conducted for the minimum data se't. An example

of how this can be done is given by Foran et al (1991).

Foran, J. A., L. L. Holst and J. P. Giesy. 1991. Effects of

photoenhanced toxicity of anthracene on ecological and genetic

fitness of Daphnia magna: A Reappraisal. Environ. Toxicol. ~. 10:425-427.

4) Since it is yet to be demonstrated that simple population of

effects on individuals or populations are possible at the current

time how will more complex models be used in the RA process?

1) This section is well done. Very insightful.

4.2.4 Ecos~rste.. Models:

1) I suggest aggregation at lower levels of organization at

greater levels of organization.l This would result in models of

the greatest complexity of intermediate levels of organization.

These woulcL be those that would be affected by effects of stressors

at greater and lesser levels of organization. Thus, the models

would be targeted at those processes that would be most likely to

be observed in a moderate period of time and also most amenable to

be tested in various cosums.

4.2.5 Lan~;cape and Reqional Models:

1) Use an environmental checklist of factors expected to change

for non-chemical effects to develop a combinatorial screening

system for chemicals with suggestions of the greatest probability

of effects such as where and when not to use.

1) P. 9-26 Para 3, L. 1 Delete "all too"

4.2.7 blplc:mentation:

1) More discussion is needed on how modeling efforts in the

ecological risk assessments will be implemented. The SAB requests

a simplification of the risk assessment process, which should

result in a concomitant decrease in the data required in the

process. However, the proposals made in the chapter seem to

E-176
indicate that more complex models will be used more frequently in

the RA process. How can these tow suggestions be reconciled?

2) A least for newly manufactured chemicals no results of effects

studies are required. If the type of modeling effort indicated is

to be used, I suggest that we make a recommendation for the use of

some minimum data set.

3) Few good models exist for the most simple environmental fate

properties of organic compounds such as photolysis, hydrolysis and

chemical oxidation. The section should mention a need for .better

data and understanding of these processes, but especially

biological transformation processes.

4.3.1 Cos:.;

1) There are two primary uses of the various sizes of cosms.

These are to gain more realistic exposure regimes. An example of

this is the toxicity of Polycyclic aromatic hydrocarbons (PAH)

which are photo-toxic and thus much more toxic in full sunlight

than under laboratory conditions. alternatively , metals for

instance can be much less toxic in more complex systems where the

available for is less due to a reduced activity. The second is

that cosms are an efficient way to test a number of species with

different sensitivities simultaneously. Cosms should not be used

to look for secondary effects of stressors at eh community or

ecosystem level of organization.

4.4.2 Toxicity Risk Assess_ent Models in the Ecosystell ConteXt:

1) P. 9-37, Para 1. Discuss expert systems here in the context

of ecological risk assessments. I think that models should be used

in an expert system context and as part of a tiered approach.

2) I am concerned that a greater use of models in a regulatory

context will lead to greater uncertainty and potentially

obfuscation of the assessment process.

4.4.3

4.7 MUltiple stressors

This section need to be strengthened.

1) Need more discussion of the effects of type II errors on the

risk assessment process.

2) It is more likely that the effects of chemical stressors will

be accurately predicted than the effects of non-chemical stressors

such as temperature or habitat loss or fragmentation.

5 .1. Qualitative versus Quantitative Assessment:

1) P. 9-48 Para 4. More discussion of these concepts is needed,

E-l77
both by the review group and in the chapter. Discuss embodied

information. in the context of qualitative vs quantitative risk

assessments.

E-178
Cross-Cutting Comments

William J. Adams

Robert A. Bachman

Lev R. Ginzburg (Addresses Issue Papers #3, 5, 7, and 9)

Kent W. Thornton

Frederic H. Wagner

E-179

Review by William J. Adams

Cross-Cutting Issues

C-l. Exposure Terminology: This subject needs to be discussed in detail and cannot

be resolved by myself with a few quick comments. Discussion and standardization of

the terms exposure characterization, stressor characterization, stress regime, disturbance,

and exposure should be discussed at the workshop.

EPA's Framework for Ecological Risk Assessment

C-2. Overall Process (figure 1): I agree with the recommendation that the data acquisition,

verification, and monitoring box be moved inside the risk assessment box. This will tie

the processes closer together, which is the way they work. Whether or not the box with

the dotted line is moved into the problem formulation box is of little concern since the

concept portrayed is the same either way.

Problem Formulation (figure 2): I probably agree with this recommendation for the

following reason. When you are performing a risk analysis you need to select the

important eco-components and exposure components to formulate a conceptual model for

how the agent and the appropriate ecological components interface or co-occur.

Assessment endpoints are not needed at this point in time.

I see no reason to differentiate between ecosystem and ecological system.

Analysis (figure 3): I agree that the boxes for exposure and stressor-response profiles can

be eliminated as long as the concepts are embodies in the boxes above. I would also add

that the parallel boxes for ecological response analysis and! exposure analysis could be

eliminated for the same reasons (Le., the stressor characterization and evaluation of

relevant effects data boxes embody the concepts of analyzing and profiling the data).

This would simplify the problem formulation box considerably.

Risk Characterization(figure 4): I tend to agree with this recommendation. I would go

a little further and not only eliminate the interpretation of ecological significance box,

I would simply this risk description section into one box entitled Ecological Risk

Summary.

C-4. I think the terms prospective, retrospective, effects-driven, and source-driven are

adequately differentiated. I had difficulty with the concept that an effects-driven

assessment is only for the PUl'P0se of determining the causative agent, or for detennining

the magnitude and extent ofthe observed effects. Perhaps this should be discussed at the

workshop with a view towards modifying this slightly.

C-5. The dimensions of exposure are adequate from the viewpoint of chemical exposures.

There is room for additional discussion relative to non chemical stressors.

C-6. No comment.

C-7. I thought the authors of the Characterization of Exposure paper did a good job of

bringing into the paper at several points the concept of anthropogenic disturbances as

related to characterization of exposure. While the concept has been given a much higher

profIle than in past documents, there is a need to demonstrate how exposure data are

analyzed and exposure profiles are developed for these types of data.

E-181

Review by Robert A. Bachman

Cross-cutting Issues

C-7. As the process of risk assessment moves more and more

from the physico-chemical arena into the socio-biological arena,

it may be necessary to establish clear overall guidelines or

sideboards for the fra~ework for ecological assessment. It is

unclear to me how or where the uncertainties regarding the

predictability of natural systems are to be dealt with or how

concepts such as the recovery of ecosystems are to be defined.

For example, is it possible to define at all what is meant by the

"recovery" of an ecosystem? Is it necessary or desirable?

Questions such as to what extent can the direction or progression

of ecosystems be predicted and how the distinctions between

"natural" and "anthropogenic" effects are to be made, need to be

addressed. It might be helpful to explicitly define or specify

the assumptions that have implicitly been made in the formulation

of the risk assessment framework in order that resource managers

and decision makers can understand the robustness of the risk

assessment product.

E-183

Review by Lev R. Ginzburg

Cross-cutting issue: Software

The spread of ('canned') software is threatening to the theoretical priesthood in ecology

because it gives away their power (or a reasonable equivalent to it) to every motivated

ecologist. Just as nostalgia for slide rules and long division did not prevent the spread of

calculators, neither will theoreticians prevent the inevitable increase in availability and

application of software for ecological risk assessment. Therefore, available software

useful for specific tasks should be referenced and reviewed in this volume. Such reference would not constitute any endorsement, but would be helpful to readers interested

in actually applying the approaches discussed. I am somewhat familiar with the

software listed below, but this list should be expanded to be reasonably comprehensive.

@RISK (Salmento et aI. 1989) is a software add-in for Lotus 1-2-3 spreadsheets for doing

Monte Carlo propagation of probabilistic uncertainty. Source: Palisade Corporation; 31

Decker Road; Newfield, New York 14867.

CASM (DeAngelis et aI. 1989) is DOS software implementing a risk assessment simulation of plankton-planktivore-piscivore ecosystem. Source: Environmental Sciences

Division; Oak Ridge National Laboratory; P.O. Box 2008; Oak Ridge, Tennessee 37831;

EPA Research Laboratory; Duluth, Minnesota.

CRYSTAL BALL (Burmaster and Udell 1990) is software for Excel spreadsheets for doing

Monte Carlo propagation of probabilistic uncertainty. Source: Decisioneering; 1380

Lawrence Street, Ste. 610; Denver, Colorado 80204.

EUA (O'Neill et al. 1982) is DOS software (isn't it?) that translates toxicity summaries into

consequences on biomass production in lake ecosystems. Source: Environmental

Sciences Division; Oak Ridge National Laboratory; P.O. Box 2008; Oak Ridge, Tennessee

37831. .

MEPAS (Droppo et al. 1991) is DOS software for screening environmental and human

health impacts from exposure through multiple media (soil, air, etc.) to hazardous and

radioactive releases. Source: Battelle Pacific Northwest Laboratory; P.O. Box 999; Richland, Washington, 99352.

PC-ILWAS (Chen and Gomez 1993) is Windows software implementing a finite-element

simulation of watershed dynamics including several important hydrological, chemical,

and biological mechanisms. It is a microcomputer version of the mainframe code

ILWAS. Source: Systech Engineering; 3744 Mt. Diablo Blvd., Suite 101; Lafayette, California 94549.

PGSM (Chen et aI. 1994) is DOS software for integrating impacts of multiple simultaneous stresses on plant physiology to predict consequences for growth, carbon-balance,

and other variables. Source: Systech Engineering; 3744 Mt. Diablo Blvd., Suite 101;

Lafayette, California 94549.

QS-eALC (Kirchner 1992) is DOS software for analytical and Monte Carlo propagation of

probabilistic uncertainty in mathematical operations. Source: Quaternary Software; Box

9521; Fort Collins, Colorado 80525.

Cross-cutting issue Risk Assessment Forum Issue Paper Review

E-185

Ginzburg
RAMAS (Ferson et aI. 1989; Ferson and Ak~akaya 1992) is DOS software for assessing

risks of decline or extinction of single-species populations or metapopulations. Source:

Applied Biomathematics; 100 North Country Road; Setauket, New York 11733.

RISK CALC (Kuhn and Ferson 1994; Ferson and Kuhn 1992; 1994) is Windows software

for propagating uncertainty through mathematical expressions using fuzzy arithmetic.

Source: Applied Biomathematics; 100 North Country Road; Setauket, New York 11733.

SWACOM (O'Neill et aI. 1982; Barnthouse et al. 1986; Bartell et aI. 1989) is DOS software

for modeling pelagia of lake ecosystems. Source: Environmental Sciences Division; Oak

Ridge National Laboratory; P.O. Box 2008; Oak Ridge, Tennessee 37831.

TREGRO (Weinstein and Yannai 1994) is Macintosh software for integrating impacts of

multiple simultaneous stresses on plant physiology to predict consequences for growth,

carbon-balance, and other variables. Source: Boyce Thompson Institute; Tower Road;

Cornell University; Ithaca, New York 14753.

References

Bamthouse, L.\V.; Suter, G.W., II; Bartell, S.M.; Beauchamp, J.J.; Gardner, RH.; Linder, E.;

O'Neill, R.V.; Rosen, A.E. (1986). User's Manual for Ecological Risk Assessment. (ORNL-6251,

ESD Pub. No. 2679), Oak Ridge National Laboratory, Oak Ridge, Tennessee.

Burmaster, D.E.; Udell, E.C. (1990). A review of Crystal Ball. .1llik Analysis 10:343-345.

Chen, C.W.; Tsai, W.T.; Gomez, L.E. (1994). Modeling responses of ponderosa pine to interacting

stresses of ozone and drought. Forest Science (in press].

DeAngelis, D.L.; Bartell, S.M.; Brenkert, A.L. (1989). Effects of nutrient recycling and food-chain

length on resilience. The American Naturalist 134:778-805.

Droppo, J.G, Jr.; Strenge, D.L.; Buck, J.W.; Hoopes, B.L.; Brockhaus, RD.; Walter, M.B.; Whelen,

G. (1991). Multimedia Environmental Pollutant Assessment System Application Guidance.

(pNWD-1857), Battelle, Richland, Washington.

Ferson, S.; Ak~akaya, H.R (1992). Quantitative software tools· for conservation biology.

Computer Techniques in Environmental Studies IV, P. Zannetti (ed.), Elsevier Applied

Science, London, pp. 371-386.

Ferson, S.; Kuhn, R (1992). Propagating uncertainty in ecological risk analysis using interval and

fuzzy arithmetic. Computer Techniques in Environmental Studies .DL, P. Zannetti (ed.),

Elsevier Applied Science, London, pp. 387-401.

Ferson, S.; Kuhn, R (1994). Interactive microcomputer software for fuzzy arithmetic. Proceedings

.Q.f.tb.e High !Consequence Safety Symposium. Sandia National Laboratories [in press].

Ferson, S.; Ginzburg, L.R; Silvers, A. (1989). Extreme event risk analysis for age-structured

populations. Ecological Modelling 47:175-187. .

Kirchner, T.B. (1992). OS-CALC: An Interpreter for Uncertainty Propagation. Quaternary Software, Fort Collins, Colorado.

Kuhn, R; Ferson, S. (1994). .1llik Uncertainty Analysis Mfu. .EJ.!zzy Arithmetic. Applied

Biomathematics, Setauket, New York.

O'Neill, RV.; Gardner, RH.; Barnthouse, L.W.; Suter, G.W.; Hildebrand; Gehrs, C.W. (1982).

Ecosystem risk analysis: a new methodology. Environmental Toxicology and Chemistry

2:167-177.

Salmento, J.S.; Rubin, E.S.; Finkel, AM. (1989). A review of @Risk. Risk Analysis 9:255-257.

Cross-cutting issue Risk Assessment Forum Issue Paper Review

E-186

Ginzburg
Weinstein, D.A.; Yannai, RD. (1994). Integrating the effects of simultaneous multiple stresses on

plants using the simulation model TREGRO. Journal Q.f Enyironmental Quality 23:418-428.

Cross-cutting issue Risk Assessment Forum Issue Paper Review

E-187

Ginzburg
Papers #5 and #7: Extrapolation of toxicity bioassays to population-level

I argued elsewhere that it is impractical to conduct ecological risk assessments aboye the

level of the species. Here I would like to argue that these assessments be conducted no

lower than the level of the species.

Ecological risk assessment is sometimes characterized as a superset of human health risk

assessment, for the obvious reason that humans are one of the species in ecosys.tems. I

believe this prospective is misleading. Although they do share many areas of interest

and technical methods, the two fields have an essential difference. In human health risk

assessment, analysts are concerned about every incidence of death or disease: individuals are themselves the focus of interest. In ecological risk analysis, we are primarily

concerned with detectable impacts at the level of entire populations or whole systems.

We study individuals mostly to learn about consequences to their assemblages. (A

possible exception arises in regard to the Endangered Species Act, where concern has

been specifically targeted on 'take' of even a single individual. Endangered species,

therefore, may enjoy the same analytical attention shown to humans, but the focus of the

law is clearly on species.)

Standard toxicity bioassays report results in terms of several endpoints focused at the

level of the individual. These may include individual fecundity, growth rate, life span,

and other varialbles. However, the meaning ofsuch endpoints in terms of consequences at

the level of the population is not always evident or simple. Are decreases of similar

magnitude of similar import at the population level? What if some endpoints exhibit

increases and some exhibit decreases? It is well known that the complexities of population dynamics, including ag~- or stage-structure, density dependence, and time delays,

can magnify (or mask) impacts that are evident at the individual level so that. they

become very serious (or negligible) at the population level. Recent research has applied

standard populationmodels to interpreting toxicity bioassays (e.g., Pesch et ai. 1987; 1991;

Fersonet aI. 1993; Caswell and Martin 1993; Bridges et al. 1993; 1994). This research shows

that it is naive- to attempt to simplistically rephrase toxicity results to the level of the

population. Extrapolation of the impacts to population-level consequences requires a

carefully formulated population dynamics model.

References

Bridges, T.S.; Wright, R.B.; Gray, B.R.; Gamble, V.E.; Gibson, A.B.; Dillon, T.M. (1994). Effects of

suspended Great Lakes sediments on Daphnia magna survival, reproduction, and population

growth. [manuscript].

Bridges, T.S.; Dillon, T.M.; Moore, D.W. (1994). The use of demographic modeling to assess

sediment tmdcity with the polychaete Neanthes arenaceodentata. Presented at the 14th annual

meeting of the Society of Environmental TOXicology and Chemistry.

Caswell, H.i Martin, L.V. (1993). Life table response experiments with quantitative treatments: a

new method for decomposing effects on population growth rate. Bulletin Qf Ecological

Society 74(supplement, no.2):188

Papers #5 and #:7 Risk Assessment Forum Issue Paper Review

E-188

Ginzburg
Ferson, S.; Ak~akaya, H.R; Silva, P. (1993). Stage-structured modeling techniques illl.d software

fm: mk assessment .Qf 1be effects .Qf dredged material .QIl ili.e population dynamics .Qf aquatic

animals. Report to Waterways Experiment Station, U.s. Army Corps of Engineers, Applied

Biomathematics, Setauket, New York.

Pesch, C.E.; Zajac, RN.; Whitlach, RB.; Balboni, M.A. (1987). Effect of intraspecific density on life

history traits and population growth rate ofNeanthes arenaceodentata (Polychaeta: Nereidae) in

the laboratory. Marine Biology 96:545-554.

Pesch, C.E.; Munns,'W.R; Guljahr-Gobell, R (1991). Effects of a contaminated sediment on life

history traits and population growth rate ofNeanthes arenaceodentata (Polychaeta: Nereidae) in

the laboratory. Environmental Toxicology 10:805-815.

Papers #5 and #7 Risk Assessment Forum Issue Paper Review

E-189

Ginzburg
Papers #5 and #7: Single-species vs. ecosystem-level risk assessment

I believe that in the foreseeable future, single-species assessment (including all the spatial

complexity as needed) will remain the only practical way for ecologlcal risk assessment.

The difficulties of extrapolating from single species and laboratory conditions to a

general ecological assessment have been much discussed. There is general agreement on

the need to extend ecotoxicological assessments to higher levels of biological organization (populations, communities and ecosystems), but no agreement on how to accomplish this task. The most significant limitation prohibiting the development of risk

assessment protocols at higher levels is the state of ecological theory. In order to make

assessments at the community or ecosystem levels, ecologists need to know the processes

and interactions among species and trophic levels, in addition to interactions between the

biotic and abiotic components of natural systems. Despite recent advances in theory of

trophic interactions, there are no generally accepted models that can be used as basis of

ecosystem-level impact assessment.

Inadequacy of the current state of ecological theory for community-level and

ecosystem-level risk assessments is exemplified by the recent controversy in the ecologicalliterature involving the dynamics of trophic interactions. Most studies on food web

theory and the dynamics of trophic interactions are based on the Lotka-Volterra

predationmodel developed in the 1920's. Recently, a number of studies have challenged

the basic assumptions ofthe traditional approach (Arditi and Ginzburg 1989; Matson and

Berryman 1992; Ginzburg and Akc;akaya 1992; Arditi and Salah 1992; see review by

Hanski 1991). These studies are currently being criticized and defended (Abrams 1994;

Sarnelle 1994; Diehl et ai. 1994; Akc;akaya et al. 1994; McCarthy et al. 1994). Since ecologists cannot even agree on the very basic assumptions of food web and food chain

models, any risk assessment protocol developed at the community-level would be on

shaky ground.

The advantages of the single-species level are that (1) it is better understood than higher

levels, (2) it requires less data to treat comprehensively, and (3) it has well-defined

endpoints such as risk of decline or extinction. The Endangered Species Act is a perfect

example of a reasonable legal compromise between what needs to be done (conserve

habitats and ecosystems) and what can be done (risk assessment at the single-species

level). The implementation of the act has reduced the restrictive aspects of the singespecies approach by focusing on species considered to be 'indicators' of ecosystem stress

(as a result of their threatened status), and as 'umbrella' species (as a result of their large

habitat require'ments). As much as we would like to be able to evaluate ecological risks

at the ecosystem level, we will be practically constrained to the single-species level for the

foreseeable future.

Referettces

Abrams, P.A. (1994). The fallacies of 'ratio-dependent' predation. ,Ecology (in press).

Ak~akaya, H.R.; Arditi, R.; Ginzburg, L.R. (1994). Ratio-dependent predation: an abstraction that

works. .Emll~ (submitted).

Papers #5 and #7 Risk Assessment Forum Issue Paper Review

E-190

Ginzburg
Arditi, R; Ginzburg, L. R (1989). Coupling in predator-prey dynamics: ratio-dependence. Journal

clTheoretical Biology 139:311-326.

Arditi, R.; Salah, H. (1992). Emprical evidence and the theory of ratio-dependent consumption.

Ecology 73:1544-1551

Diehl, S.; Lundberg, P.A.; Gardfjell, H.; Oksanen, L.; Persson, L. (1994). Daphnia-phytoplankton

interactions in l~kes: is there a need for pragmatic consumer-resource models? American

Naturalist (in press).

Ginzburg, L.R; Ak~akaya, H.R (1992). Consequences of ratio-dependent predation for steady

state properties of ecosystems. Ecology 73:1536-1543

Hanski, 1.(1991). The functional response of predators: worries about scale. Trends in Ecology

·smd Eyolution 6:141-142.

Matson, P.; Berryman, A. (1992). Ratio-dependent predator-prey theory. Ecology 73:1529.

McCarthy, M.A.; Ginzburg, L.R; Ak~akaya, H.R Predator interference across trophic chains.

Ecology (submitted).

Sarnelle,.o~ (1994). Inferring process from pattern. Ecology (in press)

Papers #5 and #7 Risk Assessment Forum Issue Paper Review

E-191

Ginzburg
Paper #9: Fuzzy sets and fuzzy arithmetic

I was pleased to see fuzzy set theory mentioned. Fuzzy set theory and its derivative, fuzzy

arithmetic, is uSE~ful for uncertainty propagation in two circumstances: (1) when empirical information is very spotty, and (2) when uncertainty is non-statistical in nature. I know of three

significant examples of the application of fuzzy set theory to environmental risk assessment.

Although fuzzy set theory has occasionally been used in ecology (e.g., Bosserman and Ragade

1982), the application of fuzzy set theory to ecological risk assessment will likely focus on fuzzy

arithmetic (Kaufmann and Gupta 1985). Fuzzy arithmetic is a refinement of interval analysis that

permits propagation of uncertainty through mathematical expressions or complex models.

Fuzzy arithmetic is part of possibility theory which was introduced by Zadeh (1978; Dubois and

Prade 1988). Possibility theory is analogous to probability theory but can be used successfully

even when only very poor empirical information is available. Duckstein et al. (1990) and

Bardossy et ai. (1991) reviewed the potential use of fuzzy sets in environmental human health

assessments. Ferson (1994) applied fuzzy arithmetic to a probabilistic ecological risk assessment

of a fishery. Ferson and Kuhn (1992; 1994) describe software implementing fuzzy arithmetic.

When a full probabilistic analysis is not possible because of a lack of empirical understanding

about the distributions of the variables involved, it is still possible to use fuzzy arithmetic to get

a reasonable, albeit crude, estimate of the uncertainty about a projection. In other cases, when the

nature ofuncertainty is notstatistical in the first place (such as when it is generated by systematic

mensuration bias or measurement error), fuzzy arithmetic may be more appropriate than probability theory to project uncertainty.

References

Bardossy, A.; Bogardi, I.; Duckstein, L. (1991). Fuzzy set and probabilistic techniques for healthrisk analysis. Applied Mathematics and Computation 45:241-268.

Bosserman, Rv".; Ragade, R.K. (1982). Ecosystem analysis using fuzzy set theory. Ecological

Modelling 16:191-208.

Dubois, D.; Prade, H. (1988). Possibility Theory: An Approach to Computerized Processing Qf

Uncertainty. Plenum Press, New York

Duckstein, L.; Bardossy, A.; Barry, T.; Bogardi, 1. (1990). Health risk assessment under uncertainty: a fu2:zy-risk methodology. Risk-Based Decision Making in Water Resources, Y.Y.

Haimes and B.Z. Stakhiv (eds.), American Society of Engineers, New York.

Ferson, S. (1994,). Using fuzzy arithmetic in Monte Carlo simulation of fishery populations.

Management of Exploited Fish, T. Quinn (ed.), proceedings of the International Symposium

on Management Strategies for Exploited Fish Populations, Anchorage, 1992, Alaska Sea Grant

College Program, AK-SG-93-02 [in press].

Ferson, S.; Kuhn, R (1992). Propagating uncertainty in ecological risk analysis using interval and

fuzzy aritm.netic. Computer Techniques in Environmental Studies IV, P. Zannetti (ed.),

Elsevier Applied Science, London, pp. 387-401.

Ferson, S.; Kuhn, R (1994). Interactive microcomputer software for fuzzy arithmetic. Proceedings

cl~ High S:onsequence Safety Symposium, Sandia Nationol Loborotories [in press].

Kuhn, R; Ferson, S. (1994). Risk Cole: Uncertointy Anolysis with Fuzzy Arithmetic. Applied

Biomathematics, Setauket, New York.

Zadeh, L. (1978). Fuzzy sets as a basis for a theory of possibility. Fuzzy Sets Systems 1:3-28.

Paper #9 Risk Assessment Forum Issue Poper Review

E-192

Ginzburg
Papers #3 and #9: Single-population vs. metapopulation

While ecological risk analysis at or above the level of the community is not supported by

current ecological theory, current methods can comprehensively model several population of one species. In the Issue Papers, ecological risk assessments are discussed at the

population-level and the landscape-level, but these two levels are mostly discussed

independently of each other. Metapopulation dynamics offers a way to integrate the

assessments at these two levels, as well as to make assessment methods at each of these

levels more realistic and applicable to natural populations and landscapes.

Habitat fragmentation as a result of human impact and natural spatial heterogeneity

cause most endangered species to exist in a small number of relatively isolated populations that may occasionally exchange individuals (a metapopulation). The need to evaluate

management options (such as reserve design, hoanslocations and reintroductions) and to

assess human impact (such as increased fragmentation and isolation) at the metapopulation level have made the metapopulation concept one of the most importantparadigms

in conservation biology (Gilpin and Hanski 1991; Burgman et al. 1993).

Factors operating at the metapopulation level, such as correlations (Gilpin 1988; Harrison

and Quinn 1989; Ak~akaya and Ginzburg 1991) and dispersal (Burgman et al. 1993), make

it impossible to extrapolate the risk assessment at the population-level to an assessment

at the species-level, unless metapopulation dynamics are explicitly incorporated into the

assessment. The metapopulation approach has been integrated with landscape-level

data, using geographic information systems (Ak~akaya1994), and using spatially-explicit

metapopulation models (e.g., see LaHaye et al. 1994 and Lamberson et al. 1992, for examples of risk analysis for two different spotted owl metapopulations). Spatial distribution

of single species should be and can be taken into account in ecological risk assessm~ntso

References

Akc;akaya, H.R. (1994). RAMAS / GIS: Linking LandscapeDataWith PQpulatiQn Viability Analysis

(versiQn 1.0). Applied BiQmathematics, Setauket, New YQrk

Akc;akaya, H.R.; Ginzburg, L.R. (1991). ECQIQgical risk analysis fQr single and multiple pQpulatiQns. Pages 73-87 in: Species CQnservatiQn: A PQpulatiQn-BiQIQgical ApprQach. A. Seitz and

V. LQeschcke (eds.) Birkhaeuser Verlag, Basel.

Burgman, M.A.; FersQn, S.; Akc;akaya, H.R. (1993). Risk Assessment in CQnservatiQn BiQIQgy.

Chapman and Hall, PQpulatiQn and CQmmunity BiQIQgy Series.

Gilpin, M.E. (1988). A CQmment Qn Quinn and Hastings: extinctiQn in subdivided habitats.

CQnservatiQn BiQIQgy 2:290-292.

Gilpin, M.; Hanski, I. (1991). MetapQpulatiQn dynamics. BiQlQgical Journal Qf the Linnean SQciety

42:nQs 1 &2.

HarrisQn, S.; Quinn, J.P. (1989). CQrrelated envirQnments and the persistence Qf metapQpulatiQns.

GikQS 56:293-298.

LaHaye, W.S.; Gutierrez, RJ.; Akc;akaya, H.R (1994). SpQtted Qwl metapQpulatiQn dynamics in

sQuthern CalifQrnia. JQumal.Qf Animal ECQlogy (in press).

LambersQn, R.; McKelvey, R; NQQn, B.R; VQSS, C. (1992). A dynamic analysis Qf northern spotted

Qwl viability in a fragmented landscape. ConservatiQn BiQIQgy 6:505-512.

Papers #3 and #9 Risk Assessment FQrum Issue Paper Review

E-193

Ginzburg
Paper #5

(page 5-48, Secltion 5.1.4). The last sentence may be very misleading. After all, probabilistic modeling is only possible after a considerable amount of information on a species or

system has bee:n amassed.

(page 5-51). ROPIS is not a model; it was a research program (Goldstein and Ferson

1994). Howev4~r, it produced two models of direct interest here: TREGRO (Weinstein

and Yannai 1994) and PGSM (Chen et al. 1994). Both can be used to estimate the

population- or community-level consequences of physiological impacts on plants from

one or multiplE! interacting environmental stresses.

References

Chen, C.W.; Tsai., W.T.; Gomez, L.E. (1994). Modeling responses of ponderosa pine to interacting

stresses of 02:one and drought. Science [in press].

Goldstein, R.; Ferson, S. (1994). Response of Plants to Interacting Stresses (ROPIS): program

rationale, design, and implications. kuu:na.l cl Enyironmental Ouality 23:407-411.

Weinstein, D.A.; Yannai, R.D. (1994). Integrating the effects of simultaneous multiple stresses on

plants using the simulation model TREGRO. TournaI Qf. Enyironmental Duality 23:418-428.

Paper #5 Risk Assessment Forum Issue Paper Review

E-194

Ginzburg
Review by Kent W. Thornton Review Comments - 28 Ju.1y 1994, ---------~ ..•.." ,- .. ",.',.~' ----------------'~~

" ,

CROSS-CU'ITlNG ISSUES i' " " •

Exposure Terminoioc ' " .. ..','

, I would suggest using the terms deflnect in Issue PaPer 4:Ch¥acterizati~n of Expos,ure

because the terms are developed in both the text' and in the Glossary. These individ~s have

reviewed the literature, published m'any of the seminal papers on the topic,:CUl4 have'thpught

about the importance of incorporating physical and. biological agents', in cujditibIito. chenucar~"

in the exposure terminology. Exposure terminology represents only one'ofseveral'setS'ofterms

and definitions that are used somewhat differently among the Issue Papers, e.g., ,ecolqgic;al,

versus assessment endpoint. A very careful review and reconciliation. of terminQlogy snopld

occur among all the Issue Papers. ' ., , '

" "

.. '

Framework 017 Issue Paper Chan&es

(For the Wor~hop)

Biolo&ical Stressors

(For the Workshop)

C-4 Prospective. Retrospective. Effects-Driyen and Source-Driven Assessments

The Issue Paper on Characterization of Exposure was the only paper I recall that

distinguished among these assessment types. I think that the primary assessment type discussed

in most issue papers was a prospective, source-driven assessment. I think it is important that

retrospective and effects-driven assessments be addressed, but it is critical that these assessments

be addressed as complementary, not mutually-exclusive. There is a whole arsenal ofteehIrlques,

approaches and procedures available for conducting assessments and it would be foolish not to

use as many ofthe appropriate tools as time and funding pennits. Additional discussion on these

different assessment focuses could be forthcoming in second round issue papers or provided in

supporting documents developed specifically for guideline development.

Dimensions of Exposure

(For the Workshop)

C-6 Bioavailability and Environmentally-Realistic Exposure in Toxicity Tests

(For the Workshop)

C-7 Increased Emphasis on AnthJropo&enic Disturbances

To my knowledge, the Issue Papers focused principally on anthropogenic disturbances

and each paper emphasized we know more about assessing effects from chemicals than other

forms of stressors at local scales. Increased emphasis on other anthropogenic stressors than

chemicals at larger scales, I think, was acknowledged by each of the Issue Paper authors.

E-195

Review by Frederic H. Wagner

C -1

I now reconsider my comments above on terminology. I prefer the text-box

definitions in 4-1 for Source, Stress Regime, and Exposure. And I prefer it for Stressor

if "physical, chemical, or biological entity" is deleted and replaced with the word "agent."

I prefer the Characterization of Exposure glossary definitions of Agent and Disturbance.

The reason the latter and Exposure get confused is that "Co-occurrence" are included in

both in the 4-1 text box. It seems to me that Disturbance is the environmental

phenomenon (fire, plowing) per see Exposure is the process of the ecological component

coming into contact with that phenomenon.

C-2

Overall Process. J agree with these suggestions.

Problem Formulation.

I guess it's OK to emphasize conceptual model development, but I don't

agree with making Endpoint its output. The latter should be part of the

model.

Yes, use "ecological system."

I don't understand the arrow comment.

Analysis.

I don't understand the reason for eliminating the boxes. I don't think they

are outputs.

OK with feedback arrow.

Risk Characterization. OK as long as summary includes interpretation.

E-197
C·3

This whole issue is an extremely complex one that can't be detailed here. I hope

that we have time to discuss it at the Workshop. In part they should be discussed in

Effects Characterization.

C·4

See my c:omments above.

C-7

I think anthropogenic disturbances need much more elaboration, probably in

Characterization of Exposure. I have a few comments on this above.

Miscellaneous Comments

P. 4-12, section 1.2.3. I think this paragraph needs considerable elaboration.

P. 4-15, section 2.2. The heading needs some words. IIDefining the Spatial and

Temporal Extenr' of what? The risk? The exposure? The following paragraph talks

about the spatial and temporal extent of the assessment. Is that what's intended? If so,

I don't understand. Same question re 2.2.1 and 2.2.2.

3.2.2.2. Should this be a much more extensive section that discusses the

characteristics Clf ecological systems and how a first-order effect can have manifold

ramifications through the system? Will the assessor have a $ense of all this if there has

not been some~ elaboration of it? And these considerations should be carefully

coordinated with the Effects Characterization section. This means getting into the

complexities of community and ecosystem structure and function.

General. I think each Issue Paper should have an executive summary.

E-198
APPENDIX F

DETAILED RECOMl\1ENDATIONS FOR REVISION OF ISSUE PAPERS
11111111111
APPENDIX F

DETAILED RECOMMENDATIONS FOR REVISION OF ISSUE PAPERS

1. INTRODUCTION

Brief summaries of the recommendations for revisions of the issue papers were presented

in section 3. This appendix presents the detailed recommendations to the authors for

revisions to the papers that were developed during the individual Work Group sessions.

2. ECOLOGICAL SIGNIFICANCE

Authors: M. Harwell, B. Norton, W. Cooper, J. Gentile

Reviewers: K. Thornton, R. Bachman, T. O'Connor

Six recommendations were made to the authors of the Ecological Significance paper as

follows:

1. Define ecological significance;

2. Reorganize the issue paper;

3. Incorporate the Public Values appendix into a separate issue paper entitled "Public

Values Affecting Ecological Significance";

4. Expand discussions of attributes and criteria;

5. Incorporate additional examples; and

6. Incorporate specific pre-meeting comments, where appropriate.

2.1. Derme Ecological Significance

A working definition of ecological significance was developed by the Work Group,

which defines ecological significance as:

• A change detected or projected in the ecological system or its individual components

that exceeds a variance estimate; and

F-I
• A change in the ecological system or its components that is of sufficient type,

intensity, extent, or duration to be important to society.

2.2. Reorganize the Issue Paper

The following reorganization of the paper was recommended:

Section 1. Introduction, with Road Map to Contents of the Issue Paper

Section 2. Ecological Significance - Definition and Societal Values

Section 3. Attributes and Criteria Determining Ecological Significance

Section 4. Current Capabilities and Examples

Section 5. Relation to Framework - Future Needs

2.3. Incorporate the Public Values Appendix Into a Separate Issue Paper

Because societal values are a critical part of defining ecological significance, this topic

should not be rf~legated to an appendix. Identification of societal values initiates the problem

formulation phase of ecological risk assessment as part of assessment endpoint identification,

and it concludes the risk characterization phase by contributing to the determination of

ecological significance. Therefore, it was recommended that >societal values be discussed in a

separate issue paper ("Public Values Affecting Ecological Significance") referenced by both

the issue papers on Conceptual Model Development and Ecological Significance.

2.4. Expand ][)iscussions of Attributes and Criteria

The attributes of ecological significance should be expanded to include:

• Temporal scale (duration of change, time to recovery, life history, etc.);

• Spatial s.cale (extent, refugia); and

• Magnitude of effect change.

F-2
These attributes relate to the change in the assessment or measurement endpoint and not

the stressor or exposure regime unless the endpoint represents these regimes. The focus is

primarily on effects. It also was recommended that a decision tree/flow diagram be used to

illustrate how attributes and criteria are applied. Finally, it was recommended that the

Environmental Risk Decision Square presented in section 2 of the issue paper, but developed

in the appendix, be further discussed in this·section as another approach for describing how

ecological significance can be presented.

2.5. Incorporate Additional Examples

It was recommended that the approaches for applying the attributes and criteria and

assessing ecological significance be illustrated throug~ the .use of three or four t:~arnples,

such as:

• Assessing significance of risk at a Superfund site-Iocal-scale, potential long-term

exposure;

• Assessing significance of risk from deforestation or different forest management

practices-landscape impacts; . .

• Assessing . the significance of risk from the cumulative \lse . of hot ~ater vs. chlorine

for zebra mussel control in Lake Erie or a large river system-large-scale impacts;'

and

• Assessing the significance of risk from an oil spill-contrast a no action alternative

vs. a dispersant alternative.

3. CONCEPTUAL MODEL DEVELOPMENT

Authors: L. Barnthouse, J. Brown

Reviewers: G. Biddinger, R. Kendall, R. O'Neill

F-3
Ten recommendations were made to the authors of the Conceptual Model Development

paper as follows:

1. Provide basic information for a broader audience on the scientific method and the

use of science to make management decisions;

2. Clearly state how conceptual model development focuses the study;

3. Include references identified by reviewers;

4. Include a third case study on a waste site;

5. Reduce the level of detail on characterization of stress;

6. Add statements of scope and purpose;

7. Discuss the importance of documentation and transparency;

8. Consider including a dictionary as an alternative to a glossary;

9. Include a process flow diagram; and

10. Ensure consistency with other issue papers.

3.1. Provide Basic Information on the Scientific Method

A broader audience for the guidelines should be assumed. It was recommended that the

authors focus beyond the regulatory context and provide guidance on the use of the best

scientific methods within a good decision matrix as driven by a regulatory need. The paper

should define the basic steps in the scientific method and discuss the use of science to make

management de:eisions. The guidance should support the multitiered aspect of risk

assessment, which should be illustrated by a process flow diagram.

3.2. Clearly State How Conceptual Model Development Focuses the Study

The paper should clearly state that conceptual modeling development can help focus the

study and target the decision. The document should support building conceptual models for

both prospective and retrospective assessments.

F-4
3.3. Include References Identified by Reviewers

Additional references were identified by reviewers in pre-meeting comments and should

be included in the paper.

3.4. Include a Third Case Study on a Waste Site

An additional case study on a waste site should be included.

3.5. Reduce the Level of Detail on Characterization of Stress

3.6. Add Statements of Scope and Purpose

Statements of scope and purpose of the paper will help focus the text.

3.7. Discuss the Importance of Documentation and Transparency

A paragraph should be developed on the importance of documenting and communicating

what was left out and why. This is necessary to ensure transparency of the assessment and

to gain credibility.

3.8. Consider Including a Dictionary as an Alternative to a Glossary

In the area of terminology, the group was mixed on need for a glossary. An alternative

solution could be a dictionary. Terms to be defined in the text were identified, and it was

suggested that undefined terms not be used if an explanation within the text would suffice.

F-S
3.9. Include a Process Flow Diagram

A process flow diagram helpselucidat~ the process, especially for novices. The work

group developed a diagram, which is included as figure 4.

3.10. EnsurE~ Consistency With Other Issue Papers

Consistency with other issue papers, especially in the use of terminology, is essential.

4. CHARACTERIZATION OF EXPOSURE

Authors: G. Suter II, J. Gillett, S. Norton

Reviewers: W. Adams, L. Kapustka, F. Wagner

Five recommendations,weJ;e made, ~o the au~hdts ~f the Characterization of Exposure

paper as follows:

,

1. Follow:the exposure characterization descriptions in the Framework Report;

2. Modify'some terminology; ;, c ••

3. Revise the figures;' C· ,

4. Restructure the issue paper; and

5. Provide recommendations on performing exposure characterization for chemical and

nonchemica1 agents.

4.1. Follow the Exposure Characterization Descriptions in the Framework Report

The issue paper should be tied more closely to the Framework Report so that the major

components of exposure characterization as presented in the Framework Report also are

presented and/or summarized in the issue paper.
Reclassify

Classify Problem

....--l~ - Management Context

- Ecological Context

- Constraints

Summarize Data

- Stressors

- Ecosystems

Identify Endpoints

Assemble

Conceptual Model

Revisit

Endpoint$

Figure 4. The Process Flow Diagram Developed by the Conceptual Model Development

Work Group

F-7
4.2. Modify Some Terminology

Several terms were discussed, and modifications were suggested to provide either a more

concise or a more accurate definition. The terms include: agent, stressor, stress regime,

disturbance, co-occurrence, agent, and bioavailability. Work Group members noted that

stress regime can have two different meanings depending on the context, and it was

recommended that both definitions be included.

4.3. Revise the Figures

The figures in the issue paper were redrawn by the Work Group to be more descriptive

of the processes and entities being represented. An effort was made to follow modeling

notation where entities are in boxes and process and rates are reflected by arrows. The

authors were encouraged to modify the figures in the spirit of what was discussed.

4.4. Restructure the Issue Paper

Restructure the issue paper specifically to:

• Ensure that the connection between the Framework Report and the issue paper is

clear (possibly add a paragraph in the introduction that provides links to the

Framework Report);

• Shorten the introduction;

• Move the discussion on exposure profile from the introduction to section 3; and

• Include a section early in the paper that focuses exclusively on the major components

of exposure.

F-8
4.5. Provide Recommendations on Performing Exposure Characterization for Chemical

and Nonchemical Agents

Recommendations on performing certain aspects of exposure characterization for

chemical and nonchemical agents should be included either as part of the issue paper or

(more likely) in the ecological risk assessment guidelines.

Specifics for chemicals are as follows:

• Guidance is needed on how to deal with significant figures throughout the exposure

characterization process.

• How does one deal appropriately with data below the analytical detection limit?

• How does one construct an exposure profile?

• How does one deal with exposure data on a probabilistic basis?

• How should background exposure data be integrated with source exposure data?

• How should uncertainty be expressed as part of the exposure characterization

process?

• How can exposure pathways be collapsed or deleted, when appropriate, to facilitate

the exposure characterization?

• How does one use sensitivity analysis to streamline the exposure characterization?

Specifics for nonchemicals are as follows:

• How does one calculate exposure for nonchemical agents? What units and what

timeframe are used?

• How are nonchemical and chemical exposure data integrated and used to construct an

exposure profile?

• How is succession incorporated into exposure characterization?

F-9
5. EFFECTS CHARACTERIZATION

Authors: P. Sheehan, o. Loucks

Reviewers: J. Giddings, N. Beyer, W. Landis

Five recommendations were made to the authors of the Effects Characterization paper as

follows:

1. Retain the emphasis in the introductory section on important general concepts;

2. Clearly state that risk assessments should not be based on simplistic "indices";

3. Include additional types of effects in the sections on individual- and population-level

effects;

4. State that many ecosystem structure/function endpoints need more research and

development before they can be routinely used in risk assessment; and

5. Discuss additional research and development needs.

In other respects, the reviewers stated that the paper is comprehensive and adequate

without major r,evision; however, some minor editing is needed to increase clarity and to

bring out the organization of topics.

5.1. Retain Emphasis in the Introductory Section on Important General Concepts

Emphasis (in the introductory section) should be retained on the following important

general concepts:

• Indirect effects can be as important as direct effects.

• Natural variability can obscure effects of stressors.

• The threshold concept is useful in describing stressor-response relationships.

• Spatial, temporal, and ecological scale must be defined in problem formulation.

F-lO
5.2. Clearly State That Risk Assessments Should Not Be Based on Simplistic "Indices"

The paper should stress that risk assessments should not be based on simplistic "indices"

at the expense of detailed information. As examples: data on species abundance ranking are

more useful than a single diversity index, and the entire dose-response curve is more useful

than the LCso•

5.3. Include Additional Types of Effects in the Sections on Individual- and PopulationLevel Effects

Certain additional types of effects should be included in the sections on individual- and

population-level effects, specifically:

• Histology;

• Pathology;

• Molecular markers; and

• Estrogens (and other hormonal effects).

Also, some measurements that are chiefly used as indicators of exposure, e.g.,

biomarkers and tissue residue concentrations, can be used to help characterize potential

effects, if they can be linked to effects. For example, DDT residues in birds have been

linked to eggshell thinning.

5.4. State That Many Ecosystem Structure/Function Endpoints Need More Research

and Development Before They Can Be Routinely Used in Risk Assess~ent

The authors should emphasize that many of the ecosystem structure and function

endpoints need more research and development before they can be used routinely in risk

assessments. These ecosystem-level research and development needs include:

• Stability;

• Nonlinear ecosystem and population dynamics;

F-l1
• Nutrient cycling;

• Disease resistance;

• Diversity; and

• Biotic integrity.

5.5. Additional Research and Development Needs Should Be Discussed

Other research and development needs that should be discussed are:

• Effects of fluctuating exposure regimes; and

• Combined effects of physical and chemical stressors.

6. BIOLOGICAL STRESSORS

Authors: D. Simberloff, M. Alexander

Reviewers: J. Drake, R. Orr, J. Thorp III

The reviewers stated that only a few changes were recommended to the authors because

this is a well-wJdtten document. The changes include:

1. Clarify the community/ecosystem concepts; and

2. Include additional thoughts and guidance on practical applications.

6.1. Clarify the Community/Ecosystem Concepts

These ideas have been incorporated into a new version of the introduction that the

authors provided during the meetings. The reviewers stated that the new introduction is

exactly what th~~y had in mind, providing balance between a continuum of thought in this

area.

F-12
6.2. Include Additional Thoughts and Guidance on PIractical Applications

Including suggestions on practical applications ("how to" information) was not a charge

to the authors of the issue papers. However, the reviewers did suggest that vectors and

dispersal corridors could be discussed in more depth. It was recommended that the authors

discuss modes of dispersal other than diffusion (which may act in a fashion similar to

chemical stressors). The reviewers noted that the authors did discuss other dispersal modes

such as "jump-dispersal," species dispersing in large geographic steps, which is similar in

some sense to airborne pollutants.

7. ECOLOGICAL RECOVERY

Authors: S. Fisher, R. Woodmansee

Reviewers: J. Karr, P. Brezonik, R. Wentsel

Eight recommendations were made to the authors of the Ecological Recovery paper as

follows:

1. Consider the written pre-meeting comments of the reviewers;

2. Emphasize anthropogenic disturbance and the kind of variation it produces;

3. Stress the importance of monitoring to determine the .success of recovery;

4 Stress the uncertainties that exist in recovery;

5. Include case studies to illustrate key concepts;

6. Remove the unnecessary references to ecological theory;

7. Expand coverage of different lands of stressors; and

8. Include the proper range of disciplines in the discussion of risk assessors.

7.1. Consider the Written Pre-Meeting Comments of the Reviewers

The authors should consider the pre-meeting comments of the reviewers and incorporate

them as appropriate.

F-13
7.2. Emphasize Anthropogenic Disturbance and the Kind of Variation It Produces

The emphasis in the paper should be shifted from a discussion of natural disturbance as a

driver of variability to anthropogenic disturbance and the kind of variation it produces. It is

important to identify the ecosystem parameters that will provide the data needed to conduct

the ecological Jisk assessment.

7.3. Stress the Importance of Monitoring to Determine the Success of Recovery

It is important to stress that merely establishing a protocol for recovery will not assure

success. A program of post-action monitoring should be established to determine if the

desired recovery has occurred.

7.4. Stress the Uncertainties That Exist in Recovery

Uncertainty is involved in ecological recovery at many levels. The authors should

consider incorporating a discussion of uncertainty into the text.

7.5. Include Case Studies to TIlustrate Key Concepts

Case studies should be included to illustrate key concepts and points made in the paper.

Even if this is done only briefly, it is valuable to include the full citation and the key points

of those studies to lead the reader to these other sources.

7.6. Remove the Unnecessary References to Ecological Theory

Certain references to ecological theory, a constantly evolving science, are not necessary

to present the important points that the paper contains.

F-14
· ., ~"'.,

7.7. Expand Coverage of Different Kinds of Stressors

The coverage of the different kinds of stressors should be expanded. In addition, the

examples could include different types of ecosystems.

7.8. Include the Proper Range of Disciplines in the Discussion of Risk Assessors

The phrase "risk assessor" suggests a single person will be doing the work; it is

important to acknowledge that a range of disciplines and expertise is involved in the risk

assessment process.

8. UNCERTAINTY IN ECOLOGICAL RISK ASSESSMENT

Authors: E. Smith, B. Shugart

Reviewers: A.F. Holland, L. Ginzburg, K. Rose

This issue paper defined most of the scientific issues associated.with characterizing

uncertainty in ecological risk assessment. It did not, however, bridge the gap between the

general treatment of uncertainty provided by the Framework Report and the specific

information required to develop Agencywide guidance for ecological risk assessments.

Reviewers made the following recommendations to the authors of the Uncertainty in

Ecological Risk Assessment paper:

1. Provide more synthesis of the science of characterizing uncertainty;

2. Use a broader variety of ~xamples;

3. Integrate discussions and recommendations with those in other. issue papers;

4. Reorganize the introduction section;

5. Refocus the problem definition section;

6. Refocus the analysis-phase uncertainty section;

7. Expand and generalize the discussions in the risk characterization section;

F-15
8. Incorporate pre-meeting comments as appropriate;

9. Define terminology used; and

10. Reorganize the describing uncertainty section.

8.1. Provide More Synthesis of the Science of Characterizing Uncertainty

Within the page constraints imposed for issue papers, it would be impossible to do a

comprehensive review of the scientific literature relevant to measuring and characterizing

uncertainty in ecological assessments. The authors should therefore focus on synthesizing

what is known about the topical area and presenting it in a form that can be understood by

technical and nontechnical audiences.

8.2. Use a Broader Variety of Examples

Examples presented in this issue paper are not balanced and focus on identifying issues

for characterizing uncertainty for terrestrial ecosystem-level and statistical models. The

reviewers recommend that a broader range of organizational levels (e.g., organism,

population, community, and ecosystem), ecosystem types (e.g., freshwater, marine,

wetlands, and terrestrial), ,and model types (statistical, structural, and process) be

represented. It is particularly important that the authors present an example for

characterizing the uncertainty associated with the application of single-species population

models.

8.3. Integrate Discussions and Recommendations With, Those in Other Issue Papers

Discussions about uncertainty occur in several other issue papers including the paper on

Conceptual Model Development, Characterization of Exposure, Effects Characterization, and

Risk Integration Methods. To the degree possible, discussions and recommendations in this

issue paper should be integrated with findings of other issue papers to reduce the amount of

redundancy and prevent conflicts.

F-16
8.4. Reorganize the Introduction Section

The introduction should be reorganized to include the following:

• Clearly identify the audience for uncertainty analysis;

• Describe the critical nature of uncertainty information to the decision making process;

• Define the difference between impact assessment and risk assessment;

• Include a definition of uncertainty analysis that is consistent with that in other issue

papers;

• Identify and describe the various types of uncertainty that occur in ecological risk

assessment;

• List the objectives of this issue paper and identify where in the text each objective is

addressed; and

• Simplify table lby making it three tables structured on the major types ofuncertainty

(model structure, parameter, and natural variability).

8.5. Refocus the Problem Definition Section

The problem definition section should be refocused arou,nd the existing summary for this

section to include the following:

• Identify the uncertainty associated with the lack of knowledge and choice of

endpoints, scale, and modeling approach;

• Discuss and provide an example of the need to constrain the time scale for model

applications;

• Integrate the discussion of types of models and criteria for model selection with

discussions in the Conceptual Model Development Issue Paper;

• Integrate the existing discussion on structural uncertainty, ecosystem characterization,

and stressor characterization; and

F-17
• Provide examples of the effects of different model structures, formulations, and/or

implementation approaches and how they influence the reliability (Le., uncertainty)

analysis results. A contrast of results based on integral-type analysis approaches and

central tendency analysis approaches would be a particularly useful addition.

8.6. Refocus the Analysis-Phase Uncertainty Section

The Analysis-Phase Uncertainty section should be refocused to include the following:

• Make the introductory paragraphs more general;

• Emphasize the simple vs. complex model discussion on the bottom of pages 8 to 19;

• Include the process described in Boesch et al. (1990) and Holling (1978) on reducing

the uncertainty that results from an inadequate experimental design;

• Include reference to and discussion of how the discussion on development of an

experimental design is linked to EPA's Data Quality Objectives process or to another

strategy that answers the question "How much power is enough?"

• Include f~xamples such as those on pages 239 to 246 of Suter et al. (1993) into the

discussion on extrapolations;

• Develop a general scheme for the types of extrapolations;

• Include an example of how knowledge of magnitude of natural spatial and temporal

variation can be used to reduce uncertainty in ecological risk assessment (e.g., see

comment in section 8.7 on the power of an ANOVA. vs. ANCOVA);

• Link the discussion of computer simulation models and model credibility (validation)

and make it more general. The question that this discussion must address is how

credible and reliable are results and under what conditions do predictions apply; and

• Include a discussion on the advantages of using multiple models that have different

assumptions and endpoints as an approach for characterizing uncertainty in ecological

risk assessments.

F-18
8.7. Expand and Generalize the Discussions in the Risk Characterization Section

The discussion of risk characterization should be generalized and expanded· to include a

discussion of error propagation following the detailed written comments provided by

Ginzburg. Other specific recommendations for this section include:

• Include figures such as those on pages 45 to 46 of Suter et al. (1993) in the

introductory paragraph of this section as an example of the uncertainty that results

from integration of exposure and effects data;

• Provide an overview discussion of the effects of the independence assumption on the

characterization of uncertainty for statistical models;

• Expand the discussion on input mapping (Rose et al., 1991) to provide more details

and explain how this approach differs from a weight-of-the-evidence argument;

• Expand the discussion on power analyses to show how. increased knowledge can

. increase power (e.g., compare the power of an ANOVA and ANCOVA for the same

data set); and

• Revise the reducing uncertainties section to be a list that summarizes the contents of

this section.

8.8. Incorporate Pre-Meeting Comments as Appropriate

The authors should consider the written pre-meeting comments of reviewers and .

incorporate them as appropriate.

8.9. Define Tenninology Used

The following terminology used in this issue paper needs to defined:

• Space and time scale;

• Disturbance regime;

• Stiff system model;

• Liebig's Law;

F-19
• Scaling-up;

• Physiological model;

• Conceptual model;

• Qualitative and quantitative models; and

• Sizing and screening tools.

8.9. Reorganize the Describing Uncertainties Section

The describing uncertainty section should be reorganized to conclude the paper more

effectively by:

• Including a summary of the material presented in this section; and

• Emphasizing the value of uncertainty information to decision makers.

9. RISK INTEGRATION METHODS

Authors: R. Wiegert, S. Bartell

Reviewers: J. Bascietto, J. Giesy, P. Van Voris

Four recommendations were made to the authors of the Risk Integration Methods paper

as follows:

1. Revise section formatting;

2. Provide more balance in the discussion of different model groups;

3. Include a discussion of alternative model approaches; and

4. Include examples of each model approach.

9.1. Revise Section Fonnatting

The paper should provide consistent section formatting with regard to the discussion of

the various integration models. The model description should be followed by a discussion of

advantages and disadvantages of the model. The one section on implementation issues should

F-20
not be a "stand-alone," rather it should be included in the advantages and disadvantages for

each model type.

9.2. Provide More Balance in the Discussion of Different Model Groups

More balance should be provided in the discussions of the different model groups. In

particular, the authors should expand the discussion of cosms by utilizing the considerable

literature on micro- and mesocosms available through EPA sources, such as the Office of

Pesticide Programs and the Office of Water.

9.3. Include a Discussion of Alternative Model Approaches

The paper would benefit from the inclusion of a discussion of the results of alternative

model approaches, illustrated by a case study of an ecological risk assessment, which could

be done using hypothetical data sets if necessary or like the RAP's ecological assessment

case studies (U.S. EPA, 1993a; U.S. EPA, 1994). The exercise should array the results

comparing alternative risk integration approaches as to stressors, endpoints (reflecting

differing risk management objectives), and relative risk ranking. This may need to be a

separate EPA exercise due to the increase in scope.

9.4. Include Examples of Each Model Approach

At least one example of each model approach should be included, using graphs, charts,

and tables, where necessary, to illustrate the model and any model principles highlighted by

the authors.

P-21 ·U.S. Government Printing Office: 1995 - 651-776