540R95132
United States
Environmental Protection
Agency
Ofiice oi Emergency and
Remedial Response
Emergency Response Division
Environmental
Response
Team
Risk Assessment Guidance
for Superfund
Environmental Response Training Program
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FOREWORD
This manual is for reference use of students enrolled in scheduled training courses of the U.S.
Environmental Protection Agency (EPA). While it will be useful to anyone who needs information
on the subjects covered, it will have its greatest value as an adjunct to classroom presentations
involving discussions among the students and the instructional staff.
This manual has been developed with a goal of providing the best available current information;
however, individual instructors may provide additional material to cover special aspects of their
presentations.
Because of the limited availability of the manual, it should not be cited in bibliographies or other
publications.
References to products and manufacturers are for illustration only; they do not imply endorsement
by EPA.
Constructive suggestions for improvement of the content and format of the manual are welcome.
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RISK ASSESSMENT GUIDANCE FOR SUPERFUND
(165.6)
4 Days
This course provides participants with the fundamentals of human health and ecological risk
assessment as applied to the Superfund cleanup process. The course, as stated in EPA's Superfund
risk assessment guidance manual, is specifically designed for Superfund risk assessors, risk
assessment reviewers, remedial project managers, and risk managers. The course is based on the
following EPA documents: Risk Assessment Guidance for Superfund: Volume I - Human Health
Evaluation Manual (Parts A, B, and C); Risk Assessment Guidance for Superfund: Volume II -
Environmental Evaluation Manual; and Ecological Assessments of Hazardous Waste Sites: A Field
and Laboratory Reference Document.
The risk assessment process is presented in three stages: baseline risk assessment, development of
preliminary remediation goals, and evaluation of cleanup alternatives. In addition, the following
topics are discussed: overview of risk assessment, data collection and evaluation, exposure
assessment, toxicity assessment, absorption efficiency, overview of Parts B and C, risk
characterization, principles of ecological assessment, framework for ecological assessment, and
ecological assessment methods. Current technical and information resources are also discussed.
After completing this course, participants will be able to:
• Identify the applicable statutes, regulations, and guidance pertinent to human health
and ecological risk assessments under Superfund.
• Describe each of the four steps of the baseline risk assessment process.
• Identify and describe various assessment methods used to evaluate the effects of
contaminants on the ecosystem.
• Perform a baseline risk assessment and an ecological assessment using EPA's risk
assessment guidance documents.
U.S. Environmental Protection Agency
Office of Emergency and Remedial Response
Environmental Response Team
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CONTENTS
SECTION 1-OBJECTIVES AND VISUALS
OBJECTIVES
Overview: Risk Assessment
Planning/Scoping/Data Collection
Chemical Data Evaluation
Exposure Assessment
Quantifying Exposure
Toxicity Assessment: Noncarcinogenic Effects
Toxicity Assessment: Carcinogenic Effects
Risk Characterization
Absorption Efficiency
Overview of Parts B and C
Principles of Ecological Assessments
Framework for Ecological Assessment
Ecological Assessment Methods
VISUALS
Overview: Risk Assessment
Principles of Ecological Assessments
Framework for Ecological Assessment
SECTION 2—CASE STUDY - SPRENGER'S LANDFILL/CENTRAL MARSH SITE
SECTION 3-SUPPLEMENTAL GUIDANCE
Human Health Evaluation Manual Supplemental Guidance: Standard Default Exposure Factors
Supplemental Guidance to RAGS: Calculating the Concentration Term
Quantifying Exposure
SECTION 4—INFORMATION SOURCES FOR TOXICITY VALUES
Toxicity Values Information Sources and Hierarchy
Integrated Risk Information System - Chlordane
EPA Environmental Criteria and Assessment Office/Superfund Technical Support Center
Health Effects Assessment Summary Tables
111
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SECTION 5-ECOLOGICAL BULLETINS
ECO Update Volume 1, Number 1
ECO Update Volume 1, Number 2
ECO Update Volume 1, Number 3
ECO Update Volume 1, Number 4
ECO Update Volume 1, Number 5
USEPA Regional Coordinators/Contacts
SECTION 6-APPENDICES
Appendix A - Bibliography
Appendix B - Supplementary Materials
w
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OVERVIEW: RISK ASSESSMENT
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to:
• Define risk assessment
• : Define risk assessment, using the National Academy of
Science definition
• Describe the differences between risk assessment and risk
management
• Define the target audience for the EPA Superfund risk
assessment guidance process
• List possible disciplines needed on a risk assessment team
• Identify the applicable statues, regulations, and guidance
pertinent to EPA Superfund risk assessment
• List the four steps of the human health evaluation baseline
risk assessment process
• Identify the organization that is mandated by CERCLA/
SARA to perform health assessments
• Define baseline risk assessment
• Identify a natural resource trustee.
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PLANNING/SCOPING/
DATA COLLECTION
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to:
• State the goals of the following processes: remedial
investigation/feasibility study, human health evaluation, and
environmental evaluation
• State the purpose of the scoping meeting
• Define the following terms: data quality objectives,
sampling and analysis plan, field sampling plan, and quality
assurance project plan
• Identify four types of data to be considered in planning the
data collection phase
• Provide 10 examples of types of site information that may
be available as background data
• Describe several approaches used in establishing locations
for background samples
• Identify seven steps of an overall strategy for sample
collection.
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CHEMICAL DATA EVALUATION
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to:
• Evaluate quantitation limits
• Identify the data qualifiers and codes provide by the
QA/QC review of laboratory data from site samples
• Compare concentrations detected in blanks with
concentrations detected in samples
• Define the term "tentatively identified compounds"
• Compare sample concentrations with background
concentrations
• Develop a set of chemical data and information for use in
the risk assessment
• Summarize data collection and evaluation results.
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EXPOSURE ASSESSMENT
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to:
• Identify the three steps of the exposure assessment process
• Characterize an exposure setting
• Identify exposure pathways.
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QUANTIFYING EXPOSURE
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to:
• Identify five common variables used to quantify exposure
• Define the term "reasonable maximum exposure" (RME)
• Distinguish between an intake (administered dose) and an
absorbed dose
• Select the most appropriate chemical intake calculation and
variables to represent the exposure pathway of interest
• List assumptions associated with each exposure calculation
• Discuss the uncertainty associated with the exposure
estimated in the calculation
• Identify sources of information on exposure variables.
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TOXICITY ASSESSMENT:
NONCARCIIMOGENIC EFFECTS
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to:
• Define the following dose-response relationship and non-
carcinogenic effect terms: physiological reserve capacity,
threshold response, reference dose (RfD), and reference
concentration
• Explain the use of the following values as they apply to
dose-response evaluation: no observed adverse effect level
(NOAEL), lowest observed adverse effect level (LOAEL),
uncertainty factor (UF), modifying factor (MF), and RfD
• Distinguish among RfDs based on chronic, subchronic, and
developmental exposure periods
• Identify the three primary types of information that are
considered in toxicity assessments
• Identify the appropriate exposure periods for which toxicity
values will be applied
• Identify the appropriate toxicity values for noncarcinogenic
endpoints
• Introduce and contrast the hierarchy of toxicity information.
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TOXICITY ASSESSMENT:
CARCINOGENIC EFFECTS
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to:
• Define the following dose-response relationship and
carcinogenic effect terms: nonthreshold response, slope
factor (SF), and unit risk
• Explain the use of the following terms as they apply to dose-
response evaluation: weight of evidence, SF, and excess
cancer risk
• Identify the appropriate toxicity values for carcinogenic
endpoints
• Identify the limitations of dose-response data obtained from
laboratory studies.
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RISK CHARACTERIZATION
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to:
• Formulate conclusions regarding the health risks from
hazardous waste sites and other environmental
contamination problems given toxicity information and
exposure estimates
• Identify limitations of the risk assessment process.
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ABSORPTION EFFICIENCY
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to:
• List three situations where absorption efficiency
adjustments may be needed
• Calculate intakes and toxicity values based on absorption
efficiency.
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OVERVIEW OF PARTS B AND C
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to:
• Define "preliminary remediation goal"
• List the three types of PRGs and state which one is
discussed in Part B
• State the two criteria for the PRGs
• Describe how radiotoxicity PRGs are different from
chemical toxicity PRGs
• Define "short-term risk" and "long-term risk" as used in
Part C
• List five noncarcinogenic, short-term toxicity values
• State the main source for carcinogenic short-term toxicity
values.
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PRINCIPLES OF
ECOLOGICAL ASSESSMENTS
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to:
• Discuss objects of study in ecological assessments
• Differentiate among several types of ecosystems
• Describe the effects of contaminants on ecosystems through
changes in population size and structure
• Identify six factors influencing the ecological effects of
contaminants
• Compare various technical specialists available to help site
managers with information data collection
• Identify regional BTAGs and their responsibilities in the risk
assessment process.
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FRAMEWORK FOR ECOLOGICAL
ASSESSMENT
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to:
• Define the ecological risk assessment framework proposed
by the risk assessment forum and differentiate it from the
human health risk assessment framework
• Define the ecological assessment framework presented in the
ECO Update bulletin
• State four steps of problem formulation
• Define assessment endpoint and measurement endpoint and
'differentiate between the two
• State three key elements in exposure assessment
• State three types of information for characterizing ecological
receptors in exposure assessment
• State two methods used to quantify exposure-point
concentrations
• State the three components of ecological effects assessment
• List several possible sources of ecological toxicity
information
-------
• State the function of field assessment methods in the
ecological effects assessment
• State the function of toxicity testing in the ecological effects
assessment
• Identify where each step of the ecological assessment
framework occurs in the various stages of the RI/FS process.
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ECOLOGICAL ASSESSMENT
METHODS
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to:
• State the purpose for using the toxicity-based approach for
estimating the toxicity of environmental media potentially
contaminated with hazardous waste
• Define toxicity test and biomarker
• Identify the differences between direct and indirect toxicity
tests
• Identify the differences between acute, chronic, and life-
cycle toxicity tests
• Identify various examples of Class I and Class II toxicity
tests
• State the differences between onsite and in situ toxicity
tests
• List four advantages and disadvantages of toxicity testing
and biomarkers
• List the advantages of using indigenous organisms in field
assessments
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• Describe activities involved in an initial site visit
• Identify objects of study in terrestrial field assessments
• Distinguish between field methods required when
examining vegetation and animal populations
• State the four categories of organisms in aquatic
environments.
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NOTES
ROLE OF HUMAN HEALTH AND
ENVIRONMENTAL EVALUATIONS IN THE
SUPERFUND REMEDIAL PROCESS
Site -> P
Discovery ^
A/SI ->H±?C°-in9 *
~ NPL Listing ^
RI/FS + cR7edy
~ Selection
Environmental
Evaluation
Human Health
bvaluaiion
SUPERFUND HUMAN HEALTH
EVALUATION PROCESS
• Analysis of baseline risks
• Basis for determining cleanup goals
• Basis for comparing remedial
alternatives
• Consistent process
HHEM, page 1-1
RISK ASSESSMENT
"Risk Assessment is the use of a
factual base to define the health
effects of exposure of individuals
or populations to hazardous materials
or situations."
National Research Council
8/93
Overview
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NOTES
RISK MANAGEMENT
"Risk Management is the process of
weighing policy alternatives and
selecting the most appropriate
regulatory action, integrating the
results of risk assessment with
engineering data and with social,
economic, and political concerns
to reach a decision."
National Research Council
TARGET AUDIENCE
• Risk manager
• Remedial project manager (RPM)
• Risk assessor
• Risk assessment reviewer
HHEM, pages Hi, 1-2; EEM, page 3
Overview
8/93
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NOTES
DISCIPLINES CONTRIBUTING TO
ENVIRONMENTAL DECISIONS
Laboratory Discipline based:
and Chemistry
Field Work Biology
Toxicology
Epidemiology
^r ^
\/
Risk Multiple scientific disciplines:
Assessment Chemistry, biology, etc.
Statistics
Medicine
Models
Science policy
X1 ^7
\S
Risk Multiple disciplines:
Management Risk assessment
Economics
Politics
Law
Social values, concerns
8/93
Overview
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RISK INFORMATION ACTIVITIES IN THE RI/FS PROCESS
Project
Scoping
1
k
Review data
collected
in site
inspection
Review
sampling/
data
collection
plans
Formulate
PRGs
Determine
level of
effort for
baseline risk
assessment
->
Site
Characterization
(Rl)
Conduct
baseline
risk \
assessment
Establishment of Development & Detailed
Remedial Action Screening of Analysis of
Objectives (FS) Alternatives (FS) Alternatives (FS)
Re
PRGs
» on
assessr
AR
fine
based
rieL-
nent and
ARs
Conduc
evaluat
alterna
t risk
on of
dial
lives
NOTES
Overview
8/93
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NOTES
HHEM-PartA
• Part A of this series assists in defining
and completing a site-specific
baseline risk assessment
• Much of the information in Part A is
necessary background for Parts B
andC
Human Health Evaluation Manual (HHEM)
BASELINE RISK ASSESSMENT
Assessment of risks that might exist if
no remediation or institutional controls
were applied at a site
HHEM, page 1-11
BASELINE RISK ASSESSMENT
General Policy
Use the baseline risk assessment to
determine whether:
• A release or threatened release
poses an unacceptable risk to
human health or the environment
that warrants remedial action
Role of the Baseline Risk Assessment in Superiund Remedy
Selection Decisions
8/93
Overview
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NOTES
BASELINE RISK ASSESSMENT
General Policy
Use the baseline risk assessment to
determine whether:
• A site presents an imminent and
substantial endangerment
Role of the Baseline Risk Assessment in Supertund Remedy
Selection Decisions
BASELINE RISK ASSESSMENT
Primary Purpose
• Provide risk managers with an
understanding of the actual and
potential risks to human health and
the environment posed by the site
and the uncertainties with the
assessment
Role of the Baseline Risk Assessment in Supertund Remedy
Selection Decisions
HHEM-Part B
Part B provides guidance on using
EPA toxicity values and exposure
information to derive risk-based
preliminary remediation goals (PRGs)
Human Health Evaluation Manual (HHEM)
Overview
8/93
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HHEM-Part C
Part C assists RPMs, site engineers,
risk assessors, and others in using
risk information both to evaluate
remedial alternatives during the FS
and to evaluate the selected remedial
alternative during and after its
implementation
Human Health Evaluation Manual (HHEM)
PART A: BASELINE RISK ASSESSMENT
Data Collection
and Evaluation
Exposure Assessment
fc
Risk
Toxicity Assessment
Risk Characterization
HHEM, page 1-7
DOCUMENTS GOVERNING
SUPERFUND RISK ASSESSMENT
STATUTES
• Comprehensive Environmental
Response, Compensation and
Liability Act of 1980
(CERCLA or Superfund)
• Superfund Amendments and
Reauthorization Act of 1986
(SARA)
HHEM, page 2-2
NOTES
8/93
Overview
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NOTES
STATUTES
CERCLA/SARA: Sections 104, 105, 121
• EPA's mandate
• "...Protection of human health and
the environment..."
HHEM, page 2-3; EEM, page 7
CERCLA/SARA
Other Requirements
• Notification of natural resource
trustees
• Creation/direction of Agency for Toxic
Substances and Disease Registry
(ATSDR)
Overview
8/93
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NOTES
NATURAL RESOURCE TRUSTEES
State
State Qovernor
Indian Tribes
Tribal Chairman
designated:
State Official
designated:
Individual
or request
DOI Bureau of
Indian Affairs
as trustee
delegated:
Regional
Environmental
Officer
ECO Update, Volume 1, Number 3
8/93
Overview
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NOTES
NATURAL RESOURCE
TRUSTEES STUDIES
Preliminary Natural Resource Survey
(PNRS)
A simple screening study of a site by
a trustee to determine whether trustee
resources may have been affected and
whether further attention is warranted
EEM, page 8
NATURAL RESOURCE
TRUSTEES STUDIES
• Natural Resource Damage Assessment
(NRDA)
A damage assessment conducted by
one or more trustees if response action
will not sufficiently restore or protect
natural resources damaged by release
EEM, page 8
NATURAL RESOURCE
TRUSTEES STUDIES
Natural Resource Damage Assessment
(NRDA)
Purpose: To determine the appropriate
level of compensation from a responsible
party to trustee resource
EEM, page 8
Overview
10
8/93
-------
MSMPaM
Medical Care
I and Testing J
Is* '
Ml GuW«K« MUM*
EPA RAs and ATSDR HEALTH ASSESSMENTS
EPA Risk Assessments
• Quantitative
ATSDR Health Assessments
• Qualitative
• Statistical and/or biological • Medical or public health
models are used
• Facilitate remediation or
risk management actions
• Selection of remediation
• Regulatory
perspectives are weighted
• Evaluate human health impacts
• Pilot health effects studies.
surveillance, epidemiological
studies, or exposure registry
• Advisory
B.LMmon. 1991. ACQIH • Confennce on RAs/n DOD
DOCUMENTS GOVERNING
SUPERFUND RISK ASSESSMENT
i
REGULATION
• National Oil and Hazardous
Substances Pollution Contingency
Plan (NCP)
NOTES
HHEM, page 2-2
8/93
11
Overview
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NOTES
NCP IMPLEMENTATION
• Required under CERCLA/SARA Section
105
• The NCP Revision Section 300.120
(FR 3/8/90) charges the site-specific
OSC/RPM with
- Identifying potential impacts on public
health, welfare, and the environment
- Setting priorities for this protection
EEM, page 8 (40 CFR Part 300)
NCP GOALS
• Protect human health and the
environment over the long term
• Minimize untreated waste
• Outline responsibilities of federal and
state agencies
• Establish criteria for the remedy
selection process
HHEM, Chapters 1 and 2; FR 3/8/90 (NCP Final Rule)
NCP
"...the lead agency shall conduct a
site-specific baseline risk assessment
to characterize the current and
potential threats to human health and
the environment..."
40 CFR Part 300.430 (d)(4)
Overview
12
8/93
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NOTES
DOCUMENTS GOVERNING
HUMAN HEALTH EVALUATION
Guidance
• Remedial Investigation/Feasibility Study
(RI/FS)
• Risk Assessment Guidance for
Superfund (RAGS)
- Human Health Evaluation Manual
(HHEM)
- Environmental Evaluation Manual
(EEM)
HHEM, page 2-2
DOCUMENTS GOVERNING
HUMAN HEALTH EVALUATION
Guidance
• Applicable or Relevant and Appropriate
Requirements (ARARs)
• Superfund Exposure Assessment Manual
(SEAM)
HHEM, page 2-2
8/93
13
Overview
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NOTES
ROLE OF HUMAN HEALTH AND
ENVIRONMENTAL EVALUATIONS IN THE
SUPERFUND REMEDIAL PROCESS
Site
Discovery ^
A/SI _fc HRS Scoring ^
^ + ' NPL Listing *
RI/FS * Remedy
~ Selection
Environmental
Evaluation
Human Health
Evaluation
ECOLOGICAL ASSESSMENT
".. .a qualitative and/or quantitative
appraisal of the actual or potential
effects of a hazardous waste site on
plants and animals other than people
or domesticated species."
RAGS Volume II: Environmental Evaluation Manual
ECOLOGICAL ASSESSMENT IN
THE SUPERFUND PROCESS
Determine the appropriate level of detail
Decide whether,remedial action is necessary
based on ecological considerations
Evaluate the potential ecological effects of the
remedial action itself
Design monitoring strategies for assessing the
progress and effectiveness of remediation
8/93
Principles
-------
/VOTES
ECOLOGICAL CONCEPTS
Levels of Organization
Population (same species)
t
Community (groups of populations)
Trophic
structure
Food
chain
Living + nonliving
matter
ECOSYSTEM
ECOSYSTEM ENERGY FLOW
Secondary
Consumers
Heat
Decomposers
SUNLIGHT NUTRIENTS
Trophic Level-Food Chain
SUN* Freshwater Ecosystem
Secondary Consumers
Principles
8/93
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NOTES
LEVELS OF ORGANIZATION
• Genes
• Cells
• Organs
• Organisms
• Populations
• Communities
BASIC CONCEPTS FOR
ECOLOGICAL ASSESSMENT
Objects of study in ecology
Types of ecosystems
Effects of contaminants on ecosystems
Factors influencing the ecological effects
of contaminants
TYPES OF ECOSYSTEMS
• Terrestrial
• Wetland
• Fresh water
• Marine
8/93
Principles
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NOTES
EFFECTS OF CONTAMINANTS
ON ECOSYSTEMS
• Reduction in population size
• Changes in community structure
• Changes in ecosystem structure and
function
FACTORS INFLUENCING
ECOLOGICAL EFFECTS
• Classification of chemicals
• Physical/chemical properties
• Frequency of release
FACTORS INFLUENCING
ECOLOGICAL EFFECTS
Toxicity
Physical/chemical characteristics of
environment
Biological factors
Principles
8/93
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NOTES
EXAMPLES OF
TECHNICAL SPECIALISTS
EPA Environmental Response Team (ERT)
EPA Regional Assistance (Regions 1-5)
1 Superfund Environmental Assessment Team (SEAT)
2 Biological Technical Assistance Group (BTAG)
3 Biological Technical Assistance Group (BTAG)
4 Ecological Technical Assistance Group (ETAG)
5 Biological Technical Assistance Group (BTAG)
EXAMPLES OF
TECHNICAL SPECIALISTS
EPA Environmental Response Team (ERT)
EPA Regional Assistance (Regions 6-10)
6 No formal group at this time
7 Biological Technical Assistance Group (BTAG)
8 No formal group at this time
9 Biological Technical Assistance Group (BTAG)
10 Biological Technical Assistance Group (BTAG)
EXAMPLES OF
TECHNICAL SPECIALISTS
EPA Research Laboratories
Athens Environmental Research Lab
Cincinnati Environmental Monitoring Systems Lab
Corvallis Environmental Research Lab
Duluth Environmental Research Lab
Gulf Breeze Environmental Research Lab
Las Vegas Environmental Monitoring Systems Lab
Narragansett Environmental Research Lab
8/93
Principles
-------
NOTES
EXAMPLES OF
TECHNICAL SPECIALISTS
Regional/Field Offices
U.S. Fish and Wildlife Service (USFWS)
National Oceanic and Atmospheric
Administration (NOAA)
Principles
8/93
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-------
NOTES
PROBLEM FORMULATION
• Qualitatively evaluate contaminant release,
migration, and fate
• Identify:
- Contaminants of concern
- Receptors
- Exposure pathways
- Known effects
• Select endpoints of concern
• Specify objectives and scope
ECO Update, Volume 1, Number 2
ASSESSMENT ENDPQINT
A formal expression of the actual
environmental value to be protected
- Reduction of key population
- Disruption of community structure
Long-term persistence, abundance, or
production of populations of key
species or key habitats
EXAMPLES OF
ASSESSMENT ENDPOINTS
• Population
- Extinction
- Abundance
• Communities
- Market sport value
- Recreational quality
• Ecosystems
- Productive capability
Framework
8/93
-------
NOTES
MEASUREMENT ENDPOINT
The physical, chemical, biological, or
ecological condition that is quantified
".. .approximate, represent, or lead to the
assessment endpoint using field or
laboratory methods (Suter 1989)."
".. .assessment endpoint may have more
than one measurement endpoint associated
with it."
ECO Update, Volume 1, Number 2, page 4
EXAMPLES OF
MEASUREMENT ENDPOINTS
• Individual
- Death
- Overt symptomology
• Population
- Occurrence
- Abundance
U.S. EPA 1989. Ecological Assessment of Hazardous Waste Sites:
A Field and Laboratory Reference. EPA/600/3-89013.
EXAMPLES OF
MEASUREMENT ENDPOINTS
• Community
- Number of species
- Species diversity
• Ecosystem
- Productivity
- Nutrient dynamics
US. EPA 1989. Ecological Assessment of Hazardous Waste Sites:
A Field and Laboratory Reference. EPA/600/3-89/013.
8/93
Framework
-------
NOTES
ASSESSMENT
ENDPOINTS
vs.
MEASUREMENT
ENDPOINTS
Commercial fish species • Female reproductive hormones
Reproductive health • Number of:
- Eggs fertilized
- Embryos hatched
- Fry
- Young of year
- Spawning adults
> Chemical concentration to reduce
survival, growth, and reproduction
EXPOSURE ASSESSMENT
• Quantify release, migration, and fate
• Characterize receptors
• Measure or estimate exposure point
concentrations
ECO Update, Volume 1, Number 2
CHARACTERIZATION OF
CONTAMINATION
• Documentation of all releases
- Volume
- Duration
- Release mechanism
• Routes of migration
Framework
8/93
-------
NOTES
CHARACTERIZATION OF
CONTAMINATION
Evaluate physiochemical properties
- Solubility
- Biomagnification potential
Mechanisms of pathways
- Spatial aspects
- Temporal aspects
ENVIRONMENTAL RECEPTORS
• Characterize receptors
- Life history
- Feeding habits
- Habitat preference
• Exposure point concentrations
- Actual
- Estimated
- Quantitative
ECOLOGICAL EFFECTS
ASSESSMENT
• Literature
• Toxicity testing
• Field studies
ECO Update, Volume 1, Number 2
8/93
Framework
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NOTES
RISK CHARACTERIZATION
• Current adverse effects
• Future adverse effects
• Uncertainty analysis
• Ecological significance
ECO Update, Volume 1, Number 2
PA/SI
NPL
Lilting
1
Ecological Assessment in the RI/FS Process
L RI/FS
T Scoping *
•t
Problem
Formulation
Review
Data
Review
Sampllng/Dat
Formulate
PRQa
Determine
LOE
Remedial Development »
. Site Acton Screening ot Analysis ol
—p Characterization Objective* Alternatve* Allemativea —I
(Rl) (FS) (FS) (FS)
A
k
^
Refine
Remedial
t
^r Conduct Baseline
Ecological
Assessment
t
Conduct Risk
r Remedial
Alternative*
(Remedy >
MROO"""
TSJ
^ Eeotoglcal
v MonitonoQ
ECO Update. Volume 1, Numbers, page 7
Framework
8/93
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CASE STUDY
SPRENGER'S LANDFILL/CENTRAL MARSH SITE
CONTENTS
INTRODUCTION 1
SITE FEATURES INVESTIGATION 1
HAZARDOUS SUBSTANCES INVESTIGATION ' 4
HYDROLOGICAL INVESTIGATION 4
Surface Water - Sprenger's Landfill Unnamed Stream 4
Sediment 5
SUBSURFACE INVESTIGATIONS 5
i
Soil 5
Groundwater . • 5
CHEMICAL DATA EVALUATION 6
QUANTIFYING EXPOSURE 10
TOXICITY ASSESSMENT/RISK CHARACTERIZATION 17
BIOTA INVESTIGATION 24
EXPOSURE PATHWAYS 26
Aquatic Exposure Pathways 26
Wetland/Terrestrial Exposure Pathways 26
Risk Assessment 32
Aquatic Exposure 32
Wetland/Terrestrial Exposure 33
Carnivorous Birds 33
Insectivorous Birds 35
Carnivorous and Omnivorous Mammals 35
REFERENCES 36
LIST OF FIGURES
Figure 1. Location map 2
Figure 2. Site map 3
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Figure 3. Biota sampling stations 27
Figure 4. Central Marsh food-chain pathway model 31
LIST OF TABLES '
Table 1. Groundwater analytical data 7
Table 2. Group exposure pathway assignments 11
Table 3. Case study intake concentrations 12
Table 4. Dermal exposure assessment parameters 15
Table 5. Intake values 16
Table 6. Case study toxicity values 18
Table 7. Chronic hazard index estimates 19
Table 8. Subchronic hazard index estimates '. . . . 20
Table 9. Cancer risk estimates 21
Table 10. Risk characterization summary 22
Table 11. PCB concentrations in biota samples collected
in Middle Marsh 28
Table 12. Lethal and sublethal effects of PCB (Aroclor 1254)
on wildlife 34
-------
RISK ASSESSMENT GUIDANCE FOR SUPERFUND
CASE STUDY
SPRENGER'S LANDFILL/CENTRAL MARSH SITE
INTRODUCTION
The Sprenger's Landfill Superfund site consists of about 12 acres on the northwestern outskirts of
the city of Charterstown. The site is a former granite quarry, bounded on the north and south by
highways and on the east and west by commercial development (Figure 1).
Quarry operations began in the late 1800s and continued until 1932. According to local sources, as
many as four separate quarry pits with estimated depths up to 150 feet deep were worked on the
property (Figure 2). In 1935, the City of Charterstown assumed ownership of the property and
initially used the two southern pits for disposal of used automobiles. From the mid 1940s to about
1968, the pits and adjacent areas were used by local industry as a disposal site for wastes such as
electrical transformers and capacitors, fuel oil, volatile liquids, used tires, glass, metal, smoke stack
soot, and scrap rubber. The site was also used for disposal of other debris such as brush and trees,
demolition materials, and large timber. Industrial waste disposal was curtailed by the city in 1968
and the site was backfilled during the early 1970s. In early 1982, the State Department of Works
conducted a test boring program on the site in anticipation of construction of a commuter parking
lot. The project was tabled when electrical capacitors were encountered in the borings.
The U.S. Environmental Protection Agency (EPA) investigation of the site prior to the current
remedial investigation (RI) included installing four monitoring wells and conducting an air sampling
program in 1983 and 1984, respectively. The site was also fenced by the city in 1984 in response
to an EPA order.
SITE FEATURES INVESTIGATION
This investigation was conducted to obtain pertinent site information, such as land use and
demography, local environmental resources, and climatology, and to describe the setting of the site
prior to the RI field study. In general, the 12-acre site is atypical of land use in the immediate area.
The land to the east and west is zoned commercial. Interstate Route 66 and its interchange with
Route 1 separate the site from significant residential development to the south. The City Country
Club golf course occupies the entire area immediately to the north of the site.
The site consists of two operable units. The first operable unit is the aforementioned 12-acre
disposal area. The study area was at one time a forested wetland similar to Potoka Swamp, but was
filled in during the depression-era construction of the golf course by the Civilian Conservation Corps.
The second operable unit, Central Marsh, is located within the city golf course, which is bounded
to the south by the southern banks of a tributary of Unnamed Stream, on the north by the Potoka
Swamp, and on the east and west by fairways of the golf course. This operable unit excludes
Unnamed Stream, which travels from culverts under Ditzel Road, continues northward through the
8/93 1 Case Study
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o
2
3
O)
il
Owe
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8/93
Case Study
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golf course in a well-defined channel, bisects Central Marsh, eventually drains into the golf course
water hazards, and finally travels under the Conrail tracks and into the main body of Potoka Swamp.
The study area for this operable unit includes a 13-acre wooded wetland called Central Marsh, a 1.5-
acre wetland area bordering the Unnamed Stream 400 feet upstream of Central Marsh, and portions
of the golf course fairways and associated floodplain and watershed areas.
All wetlands in the study area are classified as bordering vegetated wetlands under state Wetlands
Protection Regulations. Central Marsh is predominantly freshwater, consisting of broad-leaved
deciduous forested wetland. Based on hydrologic sampling and quantitative hydrologic and hydraulic
studies, all of Central Marsh and large areas of the golf course lie within the 25- and 100-year
floodplain.
HAZARDOUS SUBSTANCES INVESTIGATION
Very little specific information is available regarding wastes disposed at this site because no records
were kept, either by the city or by the industries involved. A wide variety of hazardous constituents,
including volatile organic compounds (VOCs), acid and base/neutral extractable organics,
poly chlorinated biphenyls (PCBs), and toxic metals, may be present in these wastes or may result
from interaction of the wastes with one another or with the local environment. These constituents
include those that are comparatively mobile in aqueous media (e.g., volatile organics), as well as less
water-soluble species, such as PCBs and polycyclic aromatic hydrocarbons (PAHs). In addition, past
occurrence of fires at the site may have led to the formation of dioxins and dibenzofurans.
HYDROLOGICAL INVESTIGATION
The objective of this investigation was to physically characterize surface waters in the site vicinity
with reference to their possible role in contaminant movement, either in solution or through erosion
and deposition of contaminated soils. Unnamed Stream was characterized by means of a water
balance calculation, which apportions precipitation falling onto the site into the various components
of the hydrologic cycle. Results of the water balance indicated that 55 percent is returned to the air
as evapotranspiration, 36-40 percent infiltrates into the soils and contributes to groundwater, and the
remainder occurs as direct surface runoff. Groundwater is believed to discharge to the surface water
in the marsh area and in local streams. Unnamed Stream is a "gaining stream," as indicated by
increasing discharge measurements along the stream segment. Potential flooding during peak flows
indicates that a very small portion of the northwest periphery of the site area would be inundated if
the 100-year peak discharge appeared at culverts under Ditzel Road.
Surface Water - Sprenger's Landfill Unnamed Stream
Surface water throughout the study area is affected by contaminants associated with the site. Site
contaminants enter Unnamed Creek as dissolved constituents from overland runoff and from
groundwater seeps. During the hydrological investigation, 13 surface water stations were sampled.
VOCs and inorganic contaminants were detected in groundwater seeps located at the eastern edge
of the site and in lesser concentrations in the receiving stream.
Case Study 4 8/93
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Sediment
Soils have eroded from the site into the Unnamed Stream and have been transported from the site.
PCBs, PAHs, and some inorganics have been found throughout the sediments in Unnamed Stream,
Central Marsh, four golf course water hazards, and a portion of the Potoka Swamp. Concentrations
of the constituents show a general decrease away from the source location of the Sprenger Landfill
Superfund site. A more extensive description of sediment contaminants in Central Marsh is provided
in the ecological assessment portion of this case study.
SUBSURFACE INVESTIGATIONS
Soil
Most of the Sprenger's Landfill site is covered with a layer of fill that overlies the bedrock and
quarry pits. The fill is found throughout the site property, except in the northwest corner of the site
where bedrock outcrops were observed, and the southeast corner of the site, where glacial till and
swamp deposits were found. Soil samples generally contained low total concentrations of VOCs.
Unsaturated soils were primarily contaminated with PCBs, PAHs, and metals. Surficial soil samples
were taken at nine offsite locations (on the golf course). PCBs were detected in all but one sample,
with the highest concentrations found near the wetland between Central Marsh and the landfill.
Groundwater
A total of 14 bedrock monitoring wells were installed within the Sprenger's Landfill site and 6 more
were scattered around the golf course. In addition to standard borehole geophysical logging, both
seismic refraction and electromagnetic (EM) conductivity surveys were run. The geological and
geophysical evidence indicates that the shallow bedrock is highly fractured, so it will exhibit
properties of a porous medium, and groundwater will flow through the bedrock in the direction of
the hydraulic gradient. Aquifer tests, including slug tests and short-term pump tests, were conducted
and samples were collected for VOCs and full laboratory analysis for constituents on the target
compound list (TCL) and target analyte list (TAL).
Groundwater was found to be contaminated in both the overburden and the bedrock in the landfill
area. Both flow systems were hydraulically connected and were found to discharge to the surface
waters within the study area. Within the site, groundwater movement was found to be predominantly
horizontal or downward, whereas north of the site, on the golf course, predominant upward vertical
gradients were found from the bedrock to the unconsolidated materials. The overall groundwater
flow direction within the study area is to the north and northeast, with groundwater impacted by the
site eventually reaching Potoka Swamp. Contaminant concentrations were found to be reduced to
near background levels by the time groundwater reached the upgradient edge of the swamp.
8/93 5 Case Study
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CHEMICAL DATA EVALUATION
1. Objective
Develop a list of chemicals of potential concern for use in a baseline risk assessment. An
analytical data package will be reviewed according to guidance presented in Chapter 5 of the
Human Health Evaluation Manual, Part A.
2. Problem
Preliminary environmental screening at a site revealed the potential presence of organic and
inorganic contaminants in groundwater beneath several abandoned quarries. Groundwater
could be used as a drinking water source for residences and commercial facilities in the area.
Concern for public health resulted in the installation of 13 bedrock monitoring wells. (Well
screens vary in depth between 100 and 200 hundred feet below ground surface.)
Several sampling rounds were conducted to obtain groundwater analytical data for a human
health risk assessment. The data package for this exercise consists of volatile organics
analyses for samples from four of the monitoring wells. The sampling results have been
validated by the analytical laboratory and the quality assurance officer.
(
Table 1 presents the available volatile organic analytical results for the groundwater plume
sampling effort at the quarry. Qualifiers located to the right of the individual concentration
are those assigned by the laboratory; qualifiers to the left have been assigned by the quality
assurance officer. Trip blanks were prepared and analyzed in conjunction with the sampling
and analysis plan. Analytical results for the blank samples are included with the data
package. Duplicate samples were collected in conjunction with sampling efforts at
monitoring well MW-22. Analytical results from these samples were evaluated and
incorporated as the analyte concentration at a particular monitoring well location if the
duplicate sample concentration was higher than the actual well sample concentration.
3. Method
Each person will complete the following steps:
a. Evaluate the validation codes associated with the data.
b. Identify those chemicals that are positively detected in at least one sample, including:
• Chemicals with no qualifiers attached
• Chemicals with qualifiers attached that indicate known identities but unknown
concentrations (example: data qualified "J").
c. Compare the concentrations at each well to concentrations found in the background
well (MW-11 is to be used as the source of background groundwater information).
Case Study 6 8/93
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TABLE 1. GROUNDWATER ANALYTICAL DATA
(units in //g/L)
Volatile Organic Compound
Chloromethane
Bromoethane
Vinyl chloride
Chloroethane
Methylene chloride
Acetone
Carbon disulfide
1,1-Dichloroethene
1,1-Dichloroethane
1,2-Dichloroethene (total)
Chloroform
1,2-Dichloroethane
2-Butanone
1,1,1 -Trichloroethane
Carbon tetrachloride
Vinyl acetate
Bromodichloromethane
1 ,2-Dichloropropane
c/s-1 ,3-Dichloropropene
Trichloroethene
Dibromochloromethane
1 , 1 ,2-Trichloroethane
Benzene
trans-\ ,3-Dichloropropene
Bromoform
4-Methyl-2-pentanone
2-Hexanone
Tetrachloroethene
1,1,2,2-Tetrachloroethane
MW6
10 LT
10 U
130
10 U
310
10 U
5 U
5 U
5 U
700
5 U
5 U
10 U
5 U
5 U
10 U
5 U
5 U
5 U
180
5 U
5 U
30
5 U
5 U
10 U
10 U
5 U
5 U
Sample Location
MW1 1 MW22 GCA-1
10 U
10 U
10 U
10 U
5 (7
10 I/
5 U
5 ty
5 U
5 ty
J3
5 U
10 i/
5 ty
5 U
10 ty
5 U
5 ty
5 ty
5 U
5 ty
5 U
5 ty
5 ty
5 U
10 ty
10 U
5 i/
5 ty
10 U
10 I/
4,800 J°
10 L/
.y 5,300 fl°
J 2,000 flJ
5 U
5 (y
5 (/
53,000
5 U
5 (;
j 4,400 ay
5 (y
5 U
10
-------
TABLE 1. (cont.)
Volatile Organic Compound MW6
Toluene
Chlorobenzene
Ethylbenzene
Styrene
Xylene (total)
SU
58
5d/
5U
bU
Sample Location
MW1 1 MW22 GCA-1
50
bU
bU
bU
bU
12,000
bU
1,000 J
9,900
bU
280
300
280
5C/
86
Blank
bU
5U
SU
BU
5U
' U - nondetect
b J - estimated concentration
c B - blank detect.
Case Study g 8/93
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d. Compare concentrations at each well with concentrations found in the blank sample.
e. Select those chemicals that should be included on the list of chemicals of potential
concern. The entire class will participate in the final selection process.
8/93 9 Case Study
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QUANTIFYING EXPOSURE
1. Objective
Assess the exposure to onsite and offsite contaminated media using the following steps:
• Characterize exposure settings
• Determine contaminant concentrations for each pathway
• Calculate intake values for exposure pathways.
2. Problem
The second phase of the baseline risk assessment is the completion of an exposure
assessment, which includes evaluation of potential site-related exposure pathways and
exposure intake quantification. Potential exposure pathways for this site were discussed
during the exposure assessment lecture. For the purposes of the case study, each group will
be assigned two exposure pathways for evaluation. A noncarcinogenic and carcinogenic
intake value will be calculated for each assigned pathway. Class groups will evaluate select
exposure pathways (Table 2). The intake values generated during this exercise will be used
in the risk characterization phase of the baseline risk assessment.
3. Method
a. Identify and record the appropriate intake equation for each exposure pathway.
Intake equations are located in Chapter 7 of the Human Health Evaluation Manual,
Part A (HHEM) and in the Quantifying Exposure document in Section 3. Document
the rationale for selecting these equations.
b. Identify the exposure parameters that must be defined to calculate the intake for each
equation. Table 3 provides the range of concentrations and the maximum
concentration for each chemical for all media. For calculation purposes, the
maximum concentration for each contaminant of concern should be used.
c. Determine appropriate exposure parameter values for each of the exposure settings.
Exposure values are found in the following EPA documents: Standard Default
Exposure Factors: Supplemental Guidance, Exposure Factors Handbook, said Dermal
Exposure Assessment Guidance. Table 4 provides Kp, T, t*, and B values for the
indicated chemicals. These values were obtained from EPA's dermal exposure
assessment guidance. Identify the assumptions associated with each selected exposure
parameter value.
d. Calculate the intake values using the intake concentrations provided and the exposure
parameter values. Calculate both noncarcinogenic and carcinogenic intake values for
each pathway. Record the intake values on Table 5.
SAVE ALL EXERCISE-RELATED PAPERWORK.
Case Study 10 8/93
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TABLE 2. GROUP EXPOSURE PATHWAY ASSIGNMENTS
Group
Number Pathway
1 Current land use:
Future land use:
Ingestion of chemicals of potential concern in onsite soils by
site visitors (8-18 years old)
Dermal contact with chemicals of potential concern in
groundwater used by residents (adult)
Current land use:
Current land use:
Ingestion of chemicals of potential concern in groundwater
used by residents (caretaker - adult)
Dermal contact with chemicals of potential concern in offsite
soils by visitors (8-18 years old)
3
4
5
6
7
8
Current land use:
Current land use:
Current land use:
Future land use:
Future land use:
Current land use:
Future land use:
Future land use:
Future land use:
Current land use:
Current land use:
Current'land use:
Inhalation of chemicals of potential concern volatilized indoors
from groundwater during home use by residents (caretaker -
adult)
Dermal contact with chemicals of potential concern in
groundwater used by residents (caretaker - adult)
Ingestion of chemicals of potential concern in offsite soils by
visitors (8-18 years old)
Dermal contact with chemicals of potential concern in onsite
soils by residents (adult)
Ingestion of chemicals of potential concern in groundwater
used by residents (adult)
Dermal contact with chemicals of potential concern in offsite
sediments by visitors (8-18 years old)
Inhalation of chemicals of potential concern volatilized indoors
from groundwater during home use by residents (adult)
Dermal contact with chemicals of potential concern in onsite
soils by residents (adult)
Ingestion of chemicals of potential concern in onsite soils by
residents (child through adult)
Dermal contact with chemicals of potential concern in offsite
sediments by visitors (8-18 years old)
Ingestion of chemicals of potential concern in offsite
sediments by visitors (8-18 years old)
Dermal contact with chemicals of potential concern in
groundwater during home use by residents (caretaker - adult)
8/93
11
Case Study
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TABLE 3. CASE STUDY INTAKE CONCENTRATIONS
(units are fjg/L or //g/kg unless otherwise noted)
Location/Chemical
Onsite Groundwater
Benzene
Chlorobenzene
1 ,2-Dichloroethene
Naphthalene
Phenol
Toluene
Trichloroethene
Vinyl chloride
Aroclor 1 254'
Barium
Chromium
Manganese
Zinc
Groundwater (Caretaker's Well)
Benzene
Chlorobenzene
1 ,2-Dichlorobenzene
Trichloroethene
Vinyl chloride
Barium
Manganese
Zinc
Onsite Soils'
Benzene
Benzo(a)pyrene
Dibenzofuran
Naphthalene
Toluene
Trichloroethene
Concentration Range
3-1200
5-300
3.7 - 39,000
4-202
14-22
40-12,000
81-180,000
23-6900
0.55-933
17-1910
4.4-13
37-20,500
27.5-174
30"
58b
700"
180"
130b
29"
5150"
79"
34-650
59-12,000
38-1,500
44-78,000
3.1-38,000
9.5-28,000
Intake Concentration
1200
300
39,000
202
22
12,000
1 80,000
6900
933
1910
13
20,500
174
30
58
700
180
il30
29
5150
79
650
12,000
1,500
78,000
38,000
28,000
Case Study
12
8/93
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TABLE 3. (cont.)
Location/Chemical
Onsite Soils (cont.)
Aroclor 1 254
Barium
Chromium
Manganese
Zinc
Offsite Surface Soils
Dibenzofuran
Toluene
Aroclor 1254
Barium
Chromium
Manganese
Zinc
Offsite Sediments
Benzene
Benzo(a)pyrene
1 ,2-Dichloroethene
Fluoranthene
Naphthalene
Pyrene
Toluene
Vinyl chloride
Aroclor 1 254
Barium
Chromium
Lead
Manganese
Zinc
Offsite Surface Water
Benzene
Concentration Range
1.2-2.7E + 7
7.4-2,230
2.4-127
6.8-1,020
13-25,300
230
21-2,600
260-1,400
802-945
13-489
100-739
18-88
16-340
45-960
130-170
65-2,000
270
67-1,900
5-140
14-94
83-9E + 4
7.2-1,580
3.9-423
5.2-418
54-1,870
15-927
12-160
Intake Concentration
2.7E + 7
2,230
127
1,020
25,300
230
2,600
1,400
945
489
739
88
340
960
170
2,000
270
1,900
140
94
9E + 4
1,580
423
418
1,870
927
160
8/93
13
Case Study
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TABLES, (cont.)
Location/Chemical
Offsite Surface Water (cont.)
1 ,2-Dichloroethene
Naphthalene
Toluene
Trichloroethene
Vinyl chloride
Aroclor 1 254
Barium
Chromium
Manganese
Zinc
Concentration Range
2.1-14
3-99
5
1-10
4-15
1.7
1-810
4-17
3.7-5,360
2-179
Intake Concentration
14
99
5
10
15
1.7
810
17
5,360
179
• Aroclor 1254 = PCB 1254
b Actual contamination in MW-6, the caretaker's well
0 Within quarry area.
Case Study 14 8/93
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TABLE 4. DERMAL EXPOSURE ASSESSMENT PARAMETERS
Chemical
Benzene
Benzo(a)pyrene
Chlorobenzene
Dibenzofuran
trans-l ,2-Dichloroethene
Fluoranthene
Naphthalene
Phenol
Toluene
Trichloroethene
Vinyl chloride
Aroclor 1 254
Bariumb
Chromiumb
Manganese*
Zinc"
K,
(cm/hr)
2.1E-2
1.2E + 0
4.1E-2
NA'
1 .OE-2
3.6E-1
6.9E-2
5.5E-3
4.5E-2
1.6E-2
7.3E-3
1.3E + 0
1 .OE-3
1.0E-3
1.0E-3
1 .OE-3
T
(hr)
2.6E-1
2.9E + 0
4.3E-1
NA
3.4E-1
1.5E + 0
5.3E-1
3.3E-1
3.2E-1
5.5E-1
2.1E-1
5.3E + 0
c
--
~
~
t*
(hr)
6.3E-1
1.4E + 1
1.0E + 0
NA
8.2E01
7.3E + 0
2.2E + 0
7.9E-1
7.7E-1
1.3E + 0
5.1E-1
2.5E + 1
~
--
~
~
B
1 .3E-2
1.3E + 2
6.9E-2
NA
7.2E-3
8.9E + 0
2.0E-1
2.9E-3
5.4E-2
2.6E-2
2.3E-3
3.2E + 2
--
-
~
--
Source: U.S. EPA. 1992. Dermal exposure assessment: principles and applications. Interim Report.
U.S. Environmental Protection Agency. Table 5-8.
' NA - not available
b Default value for inorganic compounds
0 - indicates not applicable.
8/93
15
Cose Study
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TABLE 5. INTAKE VALUES
Land Use: Current Future (circle one)
Receptor:
Pathway:
Chemical
Concentration
CDI Noncancer
(mg/kg-day)
CDI Cancer
(mg/kg-day)
Case Study
16
8/93
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TOXICITY ASSESSMENT/RISK CHARACTERIZATION
1. Objectives
Using the toxicity assessment and risk characterization steps, complete the quantitative risk
assessment for human health due to exposure to groundwater, surface water, soil, and
sediments from the site.
2. Problem
To characterize the existing and potential human health risk from exposure to the site, a risk
characterization will be performed using information from the quantifying exposure exercise.
Toxicity information will be obtained through a review of available toxicity databases. The
quantitative risk assessment will combine this information and result in the development of
risk values and hazard indices for all appropriate exposure pathways.
3. Methods
Each group will quantify the risk associated with two exposure pathways using the following
steps:
a. The following toxicity information was obtained from the Integrated Risk Information
System (IRIS) and the Health Effects Assessment Summary Tables (HEAST)
databases (Table 6):
• Reference doses (RfD) or reference concentrations (RfC) for chemicals
associated with noncarcinogenic effects. RfC values should be converted to
RfD values using the procedure outlined in the HHEM. Record all
information on the cancer risk and chronic hazard estimation summary sheets
(Tables 7-10).
• Slope factors (SF) or unit risks (for inhalation when an SF is not available)
for chemicals associated with carcinogenic effects. Unit risk values should
be converted to SF values using the procedure outlined in the HHEM.
• Additional information indicated on the summary sheets (do this if time
allows; this information is not essential for completion of the exercise).
b. Obtain exposure (intake) information from the exposure assessment exercise answer
sheet and record this information on the summary sheets.
c. Calculate the hazard quotient (HQ) for each chemical associated with non-
carcinogenic effects.
d. Calculate the hazard index (HI) for noncarcinogenic effects for multiple chemicals in
the same pathway.
8/93 17 Case Study
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TABLE 6. CASE STUDY TOXICITY VALUES
Do Not Cite or Quote
Constituent
Benzene
Benzo(a)pyrene
Chlorobenzene
Dibenzofuran
trans-\ ,2-Dichloroethylene
Fluoranthene
Naphthalene
Phenol
Pyrene
Toluene
Trichloroethene
Vinyl chloride
Aroclor 1 254
Barium
Chromium VI
Lead
Manganese
Zinc
RfD/RfC
(oral/inhalation)
NA'
NA
2E-2b/2E-2c
NA
2E-2b/NA
4E-2/NA
4E-2d/NA
6E - 1 /NA
3E-2/NA
2E-1/4E-1
GE-S^/NA
NA
NA
7E-2/5E-4c
5E-3/NA
NA
5E-3/1.1E-4
3E-1/NA
Slope Factor
(oral/inhalation)
2.9E-2/2.9E-2
5.8E + 0/6.1E + 0
NA
NA
NA
NA
NA
NA
NA
NA
1.1E-2d/1.7E-2de
1.9E + 0'/2.4E-2C
7.7E + 0/NA
NA
NA/4.2E + 1
NA
NA
NA
Note: All values are from 1992 Integrated Risk Information System (IRIS) files unless otherwise noted.
• NA - not available
I
b Health Effects Assessment Summary Tables (HEAST), January 1991
CHEAST, March 1992
d Under review
* For use in this class only.
Cose Study
18
8/93
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TABLE 10. RISK CHARACTERIZATION SUMMARY
Exposure Pathway
Groundwater
Ingestion - current (caretaker)
Ingestion - future (resident)
Inhalation - current (caretaker)
Inhalation - future (resident)
Dermal contact - current (caretaker)
Dermal contact - future (resident)
Current exposure - caretaker
Future exposure - resident
Soil
Ingestion onsite - current (visitor)
Ingestion offsite - current (visitor)
Ingestion onsite - future (resident)
Dermal contact offsite - current (visitor)
Dermal contact onsite - future (resident)
Exposure onsite - current
Exposure onsite - future
Sediment
Ingestion offsite - current (visitor)
Dermal contact offsite - current (visitor)
Exposure offsite - current (visitor)
Surface Water
Dermal contact - current (visitor)
Dermal contact - current (golfer)
Totals
Current exposure onsite
Current exposure offsite
Future exposure onsite
Risk
HI
i
Case Study
22
8/93
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e. Identify the combination(s) of pathways that affect the same individual (or population)
for the above chemicals and calculate the HI for multiple pathways, if appropriate.
f. Calculate the excess cancer risk estimate for each chemical associated with
carcinogenic effects.
g. Calculate the total excess cancer risk estimate for multiple chemicals within a
pathway, if appropriate.
h. Identify the combination(s) of pathways that affect the same individual (or population)
for the above chemicals and calculate the excess cancer risk estimate for multiple
pathways, if appropriate.
i. Examine all phases of the case study exercise and identify areas of uncertainty in the
risk assessment.
The information to be included in the group's final analysis includes:
a. HQ values for individual chemicals
b. Excess cancer risk values for individual chemicals
c. HI and risk values for multiple substances within each pathway
d. HI and risk values for multiple pathways, if appropriate.
e. Underlying assumptions and uncertainties associated with the above values.
Guidance for the toxicity assessment and risk characterization processes can be found in
Chapters 7 and 8 of the HHEM. The following references will be available to each group:
IRIS data sheets, HEAST tables, and Exposure Factors Handbook.
The instructors will have additional summary sheets and will distribute them on request.
8/93 23 Case Study
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BIOTA INVESTIGATION
A biological investigation was conducted for Unnamed Stream, Central Marsh, and Potoka Swamp,
which are habitats potentially impacted by wastes emanating from Sprenger's Landfill. These initial
investigations included aquatic biota sampling at predetermined stations, analysis of water quality
parameters, and characterization of aquatic and terrestrial habitats.
Aquatic benthic macroinvertebrates were collected, identified, and enumerated at several stations in
Unnamed Stream and at three upstream reference stations. Fewer organisms were collected and
significantly fewer species were seen in areas near the seeps. Potoka Swamp yielded the highest
community of invertebrates, possibly attributable to the forested wetland habitat.
EPA consulted with the State Division of Fisheries and Wildlife, Natural Heritage and Endangered
Species program, to determine the potential occurrence of any endangered species including state-
listed "species of special concern." According to the Natural Heritage and Endangered Species
Program, two state-listed species of special concern had been collected in Potoka Swamp. The
spotted turtle (Clemmys guttata) and the mystic valley amphipod (Crangonyx abberans) may co-occur
on the site.
Based on the results of the wetland delineation, additional wetland areas identified in Central Marsh
include emergent wetlands, scrub-shrub wetlands, and forested upland areas. An analysis of wetland
functions and values was conducted for both wetlands using the U.S. Army Corps of Engineers
Wetland Evaluation Technique Volume II (WET II). The results indicate that Central Marsh 1) is
highly effective in providing breeding, migration, and wintering habitat for wildlife and 2) does not
provide an abundance of habitat for open water species, but will support aquatic life such as
invertebrates, tadpoles, mollusks, and crayfish. In addition, several wildlife species were evaluated
using the U.S. Fish and Wildlife Service's Habitat Evaluation Procedure (HEP). Central Marsh was
determined to be suitable for semiaquatic carnivores such as mink (Mustela vision), but less suitable
for mammals that require permanent water (e.g., muskrat) and mass producing trees (e.g., grey
squirrel).
Field observations for wildlife indicate frequent occurrence of songbirds and small mammals, as well
as frogs, snakes, turtles, and invertebrates in streambank and inundated habitats. Other animals
observed at the swamp include the red-tailed hawk, American robin, raccoon, deer mouse, and green
frog. A species of special concern, the spotted turtle (Clemmys guttata), was observed in Central
Marsh.
A biological survey showed the presence of obligate aquatic organisms, including amphipods,
freshwater clams (Spheriidae), isopods, alderfly larvae (Sialis sp.), cranefly larvae (Tipula sp.),
midge larvae (Chironomidae), tadpoles, and leeches (Hirudinea). This area could potentially support
small fish, tadpoles, mollusks, and crayfish which, in turn, could serve as food for several
indigenous predatory mammals and possibly birds.
The adjacent wetland is not large enough to warrant high habitat value, but it can support various
species of birds and nocturnal mammals.
Case Study 24 8/93
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As part of additional studies of Central Marsh, EPA conducted biological and chemical sampling
based, in part, on the concerns of the U.S. Fish and Wildlife Service for waterfowl, passerine birds,
and food for anadromous fish using the habitat. The study cpnsisted of collecting sediment, soil,
surface water, and biota samples.
During 1990, 98 sediment/soil samples, 17 pore water samples, and 14 surface water samples were
collected. Surface samples were taken with a hand auger. The top 6 inches of substrate was
composited with multiple core holes combined from a 10-foot radius. Subsurface cores were
collected from four individual 6-inch segments of increasing depth for each 2-foot core.
Pore water samples were collected from water that seeped into the 2-foot core holes left from
previous sampling. A perforated PVC well point was inserted into the core hole and water was
removed using a PVC bailer. Surface water samples were collected by directly filling the sample
containers at each sampling location. Samples for metals were filtered in the laboratory using a
0.45-micron filter. Total (unfiltered) and dissolved (filtered) metals and PCBs were of interest for
the ecological risk assessment. A quality assurance project plan and a sampling and analysis plan
were followed throughout the study. These documents were developed and approved by EPA prior
to sampling. The samples were analyzed for TCL PCBs, pesticides, and semivolatile and volatile
organics and for TAL metals. Total organic carbon was analyzed to facilitate comparison of PCB
levels with the EPA's interim sediment quality criteria.
Twenty-seven of the thirty stations sampled in the Central Marsh study area had PCB contamination.
The highest PCB concentration in the marsh was found near the Unnamed Stream and in the
upstream or upgradient areas. This finding appeared to be correlated to elevation and the frequency
of flooding, especially in areas near the stream that flood at an interval of 3 months or more. The
highest concentrations of PCBs in the entire study area were encountered in the adjacent wetland,
upstream of the marsh. Concentrations at other stations decreased with increasing elevation and
distance from the site.
VOCs were detected in 13 surface soil samples that were widely distributed in the marsh within the
3-month floodplain. VOCs were virtually undetected in the adjacent wetland and the golf course
areas.
Semivolatile organic compounds were found in all 25 sampling stations in the marsh and in 18 of
23 stations sampled in the adjacent wetland and the golf course. Compounds that were detected
include PAHs, phenols, furans, phthalates, 1,4-dichlorobenzene, and benzoic acid. PAHs ranged
from 0.040 to 2.1 mg/kg in the marsh and from 0.055 to 0.140 mg/kg in the adjacent wetland. As
with VOC concentrations, semivolatile concentrations did not exhibit a strong pattern of distribution,
but were detected more frequently at several stations near the Unnamed Stream.
The only metals to exceed site-specific background levels were manganese (22.3-1,807 mg/kg) and
iron (2,306-167,000 mg/kg), which were widely distributed in the marsh and the adjacent wetland.
The presence of iron appears to be related to disposal practices at the site, as evidenced by the dark
orange color of the sediments downstream of the disposal area. Chromium, copper, lead, vanadium,
and zinc were present in a pattern similar to that of PCBs. Sampling stations were located in
semipermanently flooded areas of the marsh in palustrine emergent wetland.
8/93 25 Case Study
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Analytical results of subsurface sediment samples from 14 stations in the marsh and the adjacent
wetland indicate that most contamination rapidly decreases with increasing depth.
Pore water samples were compared with ambient water quality criteria. In filtered samples,
dissolved PCS concentrations ranged from undetected (0.05 (tg/L) to 4.4 /ig/L, which exceed
ambient water quality criteria (0.014 /ig/L). In unfiltered samples, PCB concentrations ranged from
1.8/ig/Lto 29/ig/L.
Biota samples consisted of benthic macroinvertebrates, small mammals, amphibians, earthworms,
and plants (Figure 3). All samples were analyzed for pesticides and PCBs. Aroclor 1254 was the
only contaminant found in tissue samples. Aroclor 1254, the principle contaminant of Sprenger
Landfill, was also found in samples of sediment, soil, unfiltered water, small mammals, benthic
invertebrates, earthworms, and frogs. The highest concentrations, ranging from 0.19 to 0.73 mg/kg,
were found in the green frog (Rana clamitans melanota) (Table 11).
EXPOSURE PATHWAYS
Detailed physical, chemical, and biological information was collected and evaluated for Central
Marsh to identify aquatic and wetland/terrestrial exposure pathways critical to the transfer of PCBs
in Central Marsh and the adjacent wetland.
Aquatic Exposure Pathways
In the aquatic environment, sediment-dwelling or benthic organisms are at the base of the food chain.
These organisms are in intimate contact with the interstitial (pore) water of the sediments and many
emerge in later life stages as aquatic insects. Furthermore, in all aquatic organisms, contact with
water through respiration is an important route of uptake. Thus, aquatic species accumulate PCBs
through several pathways, including direct exposure to water and food chain bioaccumulation.
EPA evaluated areas within Central Marsh to identify those areas which support an aquatic food
chain and, thus, an aquatic exposure pathway. Based on field observations, EPA determined that
the area west of the stream in the northwest portion of Central Marsh was connected to the stream
over most of the year. Therefore, this area could be a feeding area for stream animals and could
contribute plant and animal material to the stream on a continuing basis. The area was further
identified as an aquatic area, based on the invertebrate surveys (which identified aquatic organisms
in this area), the topography, and the fact that the area is permanently flooded. Therefore, this
northwest portion of Central Marsh could represent an area that supports a significant aquatic
pathway for the biological transfer of contaminants.
Wetland/Terrestrial Exposure Pathways
Wetland and terrestrial species, such as terrestrial insects, small mammals, and birds, are not in
intimate contact with surface water or pore water. For these species, direct sediment/soil contact
and food chain exposure are predominant. In soil-dwelling organisms such as earthworms and mice,
dermal contact may play a significant role. However, in upper level consumers, PCB uptake is
primarily due to food chain (trophic) bioaccumulation.
Case Study 26 8/93
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TABLE 11. PCB CONCENTRATIONS IN BIOTA SAMPLES
COLLECTED IN MIDDLE MARSH*
Location
Species Sampled
PCB
Concentration
(mg/kg)
Station 1
Station 2
Station 3
Station 4
Station 5
Station 6
Benthos
Green frog (Rana clamitans)
Rose hips (Rosa mult/flora)
Benthos
Green frog (Rana dam/tans)
Rose hips (Rosa multiflora)
Grass seed heads (Pha/ioris arundinacea)
Benthos
Green frog (Rana clamitans)
Rose hips (Rosa multiflora)
Grass seed heads (Phalioris arundinacea)
Benthos
Earthworm
Meadow vole (Microtus pennsylvanicus)
Short-tailed shrew (Blarina brevicauda)
Rose hips (Rosa multiflora)
Benthos
Grass seed heads (Phalioris arundinacea)
Green frog (Rana clamitans)
Rose hips (Rosa multiflora)
Grass seed heads (Phalioris arundinacea)
0.1 (f
0.25
0.1 U
0.35
0.27
0.1 U
0.1 U
0.4
0.68
0.1 U
0.1 U
0.1 U
0.1 U
0.1 U
0.38-0.98 (2)c
0.1 U
0.1 U
0.1 U
0.19
0.1 U
0.1 U
Cose Study
28
8/93
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TABLE 11. (cont,)
PCB
Concentration
Location Species Sampled (mg/kg)
Station 7
Benthos 0.1 U
Green frog (Rana clamitans) 0.73
East Bank
Earthworm 2.3
Green frog (Rana clamitans) 0.39
Meadow vole (Microtus pennsylvanicus) 0.36-1.6 (3)d
Deer mouse (Peromyscus maniculatus) 0.1 6/-0.64 (3)
West Bank
Earthworm 1.8
Deer mouse (Peromyscus maniculatus) 0.27-1 (2)
White-footed mouse (Peromyscus leucopus) 0.68-0.84 (3)
Station 8
Green frog (Rana clamitans) 1.02
'Source: Charters. 1991.
" U - the analyte was not detected at the indicated concentration
0 (2) - indicates two individuals of the species
d (3) - indicates three individuals of the species.
8/93 29 Cose Study
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Figure 4 depicts a food chain pathway model that was developed for the Central Marsh Operable
Unit to represent the trophic relationships between the species present in Central Marsh. Site-specific
tissue data and literature information on the life histories and feeding habits of selected species were
used to select critical food chain pathways and target species for protection. The model was
developed to 1) evaluate the effects of contamination on environmental receptors, 2) determine
ecological assessment endpoints for remediation, 3) evaluate the impacts of remediation on the
wetland area, and 4) identify appropriate mitigating measures.
Species included in the food chain pathway model for Central Marsh were selected because they are
integral parts of important transfer pathways. Selections were based on observed abundance at the
site, presence of suitable habitat for the species, and likelihood of exposure. Abundance of the
species was judged by the number of sightings during sediment/soil and wetland studies and by
trapping conducted by EPA. Habitat suitability was based on the U.S. Fish and Wildlife Service's
HEP (U.S. FWS 1980). Species with frequent or constant exposure to sediment, soil, and water,
such as earthworms, insects, and small mammals, were included in the model. Conversely, species
were excluded from the model if they were assumed to have little or no exposure to site contaminants
or if they have been shown to have very high tolerances to the contaminants.
Specifically, raccoon were included because their tracks were observed and their food species include
small mammals, frogs, worms, and reptiles. Mink were included in the model because Central
Marsh provides the basic habitat requirements for mink, because mink are known to be susceptible
to PCBs, and because of their position as a top level consumer in an area where site-specific data
showed that many of the mink's food sources are contaminated with PCBs. Mink may also use
aquatic food sources such as fish, crayfish, tadpoles, and mollusks when an aquatic feeding area is
available, as well as small birds during a substantial portion of the year. Mink are expected to use
the Central Marsh Operable Unit because they have historically occurred in the region and they have
been recently sighted in nearby areas including the Apponagansett Swamp and ,as road kills in
neighboring Dartmouth, Massachusetts. Finally, mink tracks and the tracks of other small animals
were recently observed and photographed in Central Marsh near the Unnamed Stream.
Small mammals such as mice and shrews were included because they burrow in the soil and are
frequently prey of reptiles and other small mammals such as raccoons and mink. In addition, the
shrew is a voracious insectivore, feeding on terrestrial insects that are in intimate contact with the
sediment and soil. Amphibians such as the green frog were included because of their abundance,
because of site-specific data indicating PCB body burdens, and because they are frequently prey of
reptiles and mammals. '
American robin (Turdus migratorius) and American woodcock (Philohela minor) were included in
the food chain pathway model because they are carnivorous and their principal food source is
earthworms, which were found to carry body burdens of PCBs up to 2.3 mg/kg in Central Marsh
(Charters 1991). Earthworms also play an important role in mobilizing PCBs into the food chain
because of their contact with sediment, soil, and water. Insectivorous birds that feed on terrestrial
insects such as beetles, pill bugs, and centipedes have also been included. Although the snapping
turtle is a top level carnivore and was frequently observed in Central Marsh, it is not a target species
because of its high level of body fat and associated resistance to PCBs and other lipophilic
contaminants. The spotted turtle is largely herbivorous and, based on site-specific plant tissue data
indicating undetected PCB concentrations, has not been included. The red-tailed hawk (Buteo
jamaicensis) was observed onsite on a number of occasions, but was not included as a target species
Case Study 30 8/93
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because its home range is 0.5-2.2 square miles. Central Marsh comprises only about a maximum
of 4 percent of the hawk's range, thus reducing the percent of its diet that would come from Central
Marsh.
Risk Assessment
A variety of methods were used to assess exposure of Central Marsh wildlife species through both
aquatic and wetland/terrestrial exposure pathways. For aquatic exposure pathways, the equilibrium
partitioning method was used as a method of developing sediment quality criteria (SQC) for aquatic
portions of Central Marsh. For wetland/terrestrial pathways, exposure of upper level consumers was
evaluated by calculating potential dietary levels and comparing those levels to the toxicity data. The
ecological risk assessment for aquatic and wetland/terrestrial exposure pathways is discussed below.
Aquatic Exposure
Interim SQC were used to estimate the toxicity of the sediments and the biological impact of in-place
contaminated sediments. SQC are intended to be protective of the presence and ecological functions
of benthic invertebrates and other aquatic life. SQC are based on water quality criteria and are used
to develop limits for contaminant concentrations in the pore water of sediments. These limits are
established to protect benthic, epibenthic, and other aquatic invertebrate communities at the base of
the aquatic food chain.
EPA has derived contaminant-specific criteria for sediments from ambient water quality criteria using
the partitioning coefficient. This allows back-calculation of sediment levels that, within certain
probabilities, will not result in exceedance of water quality criteria in the pore water. The PCB SQC
were derived from the PCB ambient water quality criterion that was developed to safeguard against
bioaccumulation that could result in chronic reproductive effects in upper level consumers, as
represented by the mink (Mustela visori), a species found to be particularly sensitive. In 1988, EPA
published interim SQC (including mean values and 95-percent confidence values) for 13 chemicals
(U.S. EPA 1988). The proposed low, mean, and upper value freshwater SQC for PCBs were 3.87,
19.5, and 99.9 /xg PCB/g carbon, respectively.
Comparison of the interim PCB SQC with normalized PCB sediment data (in units of jig PCB/g
carbon) in the aquatic northwest area of Central Marsh indicates that approximately 0.4 acres exceed
the mean SQC and 0.1 acres exceed the upper SQC. Data from the biological tissue study for
Central Marsh indicate that at the Central Marsh Operable Unit, PCBs have accumulated in benthic
organisms living in sediments where PCB-normalized concentrations exceed 200 fig PCB/g carbon,
a value two times the interim upper SQC. Specifically, PCB concentrations of 0.35 and 0.40 mg/kg
were found in benthic organisms collected from sediment samples with normalized PCB
concentrations of 316 and 253 /ig PCB/g carbon, respectively.
In addition, PCBs (Aroclor 1254) were detected in filtered and unfiltered pore and surface water
samples at levels above the ambient water quality criterion for PCBs of 0.014
Given the site-specific data indicating that bioaccumulation is occurring onsite, and due to the
presence of aquatic environments in portions of Central Marsh with elevated PCB concentrations,
Case Study 32 8/93
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EPA has determined that contaminated sediments in the northwest portion of Central Marsh present
an unacceptable risk to biota at the Central Marsh Operable Unit.
Wetland/Terrestrial Exposure
EPA's ecological risk assessment used bioaccumulation and toxicity data presented earlier to conduct
a wildlife exposure assessment for species indigenous to Central Marsh, and to calculate potential
levels of contaminants in sediment and soil that would be protective of the environment. For
wetland/terrestrial pathways, EPA evaluated exposure of upper level consumers (such as the raccoon
and mink) by calculating protective sediment levels, using lowest observed effect dietary, levels and
site-specific bioaccumulation factors.
Site-specific tissue data were used to develop bioaccumulation factors (BAFs) for species such as
small mammals, earthworms, and frogs. The BAFs developed for these species were calculated as
the ratio of PCBs in the tissue to the level in the sediment/soil, as follows:
Sediment/soil x BAF = animal tissue PCB level
BAF = animal tissue PCB level
sediment/soil PCB level
This method accounts for all types of exposure, including direct contact, inhalation, soil ingestion,
and trophic magnification or food exposure. This method assumes that the exposure level of
organisms is directly proportional to the level of contaminants in the sediment/soil. This information
was used to back-calculate levels for sediment/soil that are protective of wildlife by maintaining the
food supply of targeted upper level consumers at or below lowest observed adverse effects level
(LOAEL) (Table 12).
In the exposure assessment presented below, sediment/soil protective levels were back-calculated
using the following relationship:
CmediB = LOAEL
BAF
where:
i
Cmedi. = concentration (mg/kg) of PCBs in environmental media
(e.g., sediment, soil, water)
LOAEL = dietary lowest observed adverse effect level (mg/kg)
BAF = bioaccumulation factor from the media to the food species consumed
(unitless).
Carnivorous Birds
Because of the abundance of earthworms in Central Marsh and frequent sightings of the American
robin, a sediment/soil protective level was calculated for American robin and other carnivorous birds
(e.g., woodcock) based on a protective dietary level of 5 ppm PCBs and a BAF of 0.29 for
8/93 33 Case Study
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TABLE 12. LETHAL AND SUBLETHAL EFFECTS OF PCB
(AROCLOR 1254) ON WILDLIFE"
Dietary
Exposure Exposure
Species Period (mg/kg)
Ringed turtle 3 months 1 0
doves
Mourning doves 6 weeks 1 0
Chickens 5
Mink 4 months 1
8 months 2
4 months 5
160 days 0.64
105 days 3.57
Effect
Delayed
reproductive
impairment
Hatchability of
second clutch
severely
impaired
Delayed
reproductive
impairment
Reproductive
impairment
Reduced
reproduction
High death rate
of kits
Depressed
reproduction
Severe
reproductive
effects
Reproductive
failure, extreme
weakness, and
death
Reference
Heinz et al.
1984
Peakall et al.
1972
Tori and
Peterle 1983
Heinz et al.
1984
Ringer et al.
1972
Aulerich and
Ringer 1977
Ringer et al.
1972
Platonow and
Karstad 1 973
Platonow and
Karstad 1 973
Cited in:
Eisler 1 986
Eisler 1 986
Eisler 1986
Eisler 1 986
U.S. EPA
1980
U.S. EPA
1980
' Maughan 1993.
Case Study
34
8/93
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earthworms. Assuming that earthworms comprise 75 percent of these species diet, and that Central
Marsh is 90 percent of their feeding range, a protective level of 25.5 mg/kg is indicated by the
following equation:
Sediment/soil protective level = 5 ppm PCB = 25.5 mg/kg PCBs
(0.29)(0.75)(0.9)
Insectivorous Birds
Insectivorous birds are exposed to PCBs through the .terrestrial food pathway through the
consumption of terrestrial insects. A sediment/soil protective level was calculated for insectivorous
birds using a BAF of 0.19. Assuming that terrestrial insects comprise 100 percent of the bird's diet,
and that Central Marsh is 90 percent of the feeding range, a sediment/soil protective level of 29.2
mg/kg is indicated by the following equation:
Sediment/soil prbtective level = 5 pom PCB = 29.2 mg/kg PCBs
.0)(0.9)
Carnivorous and Omnivorous Mammals
Upper trophic level carnivorous and omnivorous mammals in Central Marsh and the adjacent wetland
include raccoon and mink. Mink prefer aquatic food sources to terrestrial food sources when both
options are equally available (Linscombe et al. 1982). In Central Marsh, aquatic food sources for
mink include small fish, crustaceans, newts, mollusks, and tadpoles. Mink will also consume a
significant number of frogs when available. However, during winter when the stream may be
partially frozen and when frogs are hibernating, mink will feed largely on small mammals
(Linscombe et al. 1982). Because reproductive impairment can occur in mink at low dietary levels
in less than a year, th& dietary level of 0.64 ppm PCBs was used as an acute exposure level and
dietary exposure levels were calculated for the mink's winter (terrestrial) diet. In winter, mink will
feed largely on small mammals. Accordingly, a sediment/soil protective level for wetland terrestrial
areas outside the aquatic areas is based on a site-specific BAF for small mammals of 0.65/0.07 =
9.14. Because Central Marsh comprises 65 percent of the mink's home range of 20 acres, the
protective level is adjusted accordingly to 15 mg/kg.
Raccoon, in comparison, are omnivorous, feed opportunistically, and may consume a substantial
amount of frogs and mice when readily available, as is the case in Central Marsh. Accordingly, a
sediment/soil protective level has been calculated for raccoon. A BAF of 0.22 for frogs, a BAF of
0.07 for mice, and a protective dietary level of 1 ppm were used in the calculations. The raccoon
has a home range of 18-36 acres. It was assumed that Central Marsh comprises 50 percent of the
raccoons' feeding range and that 30 percent of their diet is composed of frogs and mice. The
following sediment/soil protective level of 45.9 mg/kg was calculated for protection of raccoon:
1 = 45.9 mg/kg PCBs
I(0.22)(0.5) + (0.07X0.5)] [(0.5)(0.3)]
8/93 35 Case Study
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In summary, using the application of site-specific bioaccumulation factors for the food chain pathway
model to PCB concentrations in Central Marsh and the adjacent wetland reveals several areas,
totalling approximately 1.9 acres, where levels derived ,to protect mink are exceeded. PCB
concentrations at sampling locations ME-22, ME-38, and SL-56 (28, 32, and 34 mg/kg PCBs,
respectively), exceed the calculated level that is protective of carnivorous birds. In addition, PCB
concentrations at sampling locations ME-38 (32 mg/kg PCBs) and SL-56 (34 mg/kg PCBs) exceed
the calculated level that is protective of insectivorous birds.
EPA has determined that actual or treated releases of hazardous substances from contaminated
sediments in Central Marsh and the adjacent wetland, if not addressed by implementing the response
action selected in thejROD for this site (U.S. EPA 1991), may present an imminent and substantial
endangerment to biota present in the environment at the Central Marsh Operable Unit.
REFERENCES
Aulerich, R.J., and R.K. Ringer. 1977. Current status of PCB toxicity to mink, and effect on their
reproduction. Arch. Environm. Contain. Toxicol. 6:279-292.
Charters, D.W. 1991. Environmental assessment, Middle Marsh Sullivan's Ledge site, New
Bedford, Massachusetts. Final Report. U.S. Environmental Protection Agency, Environmental
Response Branch. '
Eisler, R. (ed). 1986. Polychlorinated biphenyl hazards to fish, wildlife, and invertebrates: a
synoptic review. U.S. Fish and Wildlife Service Biological Report 85 (1.7).
Heinz, G.H., D.M. Swineford, and D.E. Katsman. 1984. 'High PCB residues in birds from the
Sheboygan River, Wisconsin. In: Eisler, R. (ed). 1986. Polychlorinated biphenyl hazards to fish,
wildlife, and invertebrates: a synoptic review. U.S. Fish and Wildlife Service Biological Report
85 (1.7).
ICF-Clement Associates, Inc. 1988. Endangerment assessment for the F. O'Connor site in Augusta,
Maine. EPA Contract No. 68-01-6939. Document Control No. 319-ES1-RT-FKJL-1.
Linscombe, G., N. Kinler, and R.J. Aulerich. 1982. Mink (Mustela vison). In: Wild mammals
of North America: biology, management, economics. J.A. Chapman and G.A. Feldhamer, eds.
Johns Hopkins University Press, Baltimore, Maryland, pp. 629-643.
Montz, W.E., W.C. Card, and R.L., Kirkpatrick. 1982. Effect of polychlorinated biphenyls and
nutritional restriction on barbituate-induced sleeping times and selected blood characteristics in
raccoons (Procyon lotof). Bull Environ. Contam. and Toxicol. 28:578-583.
Peakall, D.B., J.L. Lincer, and S.E. Bloom. 1972, Embryonic mortality and chromosomal
alterations caused by Aroclor 1254 in ringdoves. In: Eisler, R. (ed). 1986. Polychlorinated
biphenyl hazards to fish, wildlife, and invertebrates: a synoptic review. U.S. Fish and Wildlife
Service Biological Report 85 (1.7).
Case Study 36 8/93
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Platonow, N.S., and L.H. Karstad. 1973. Dietary effects of polychlorinated biphenyls on mink.
Can. J. Comp. Med. 30:391-400.
Ringer, R.K., R.J. Aulerich, and M. Zabik. 1972. Effect of dietary polychlorinated biphenyls on
growth and reproduction of mink. In: U.S. EPA. 1980. U.S. EPA Ambient Water Quality
Criteria for Polychlorinated Biphenyls. EPA 440/5-80-68. U.S. Environmental Protection Agency,
Office of Water Regulations and Standards.
Sanders, O.T., and R.L. Ku-kpatrick. 1977. Reproductive characteristics and corticoid levels of
female white-footed mice fed ad libitum and restricted diets containing a polychlorinated biphenyl.
Environ. Res. 13:358-363.
Tori, G.M., and T.J. Peterle. 1983. Effects of PCBs on mourning dove courtship behavior. In:
Eisler, R. (ed). 1986. Polychlorinated biphenyl hazards to fish, wildlife, and invertebrates: a
synoptic review. U.S. Fish and Wildlife Service Biological Report 85 (1.7). 72 pp.
U.S. EPA. 1980. Ambient water quality criteria for polychlorinated biphenyl. EPA 440/5-80-68.
U.S. Environmental Protection Agency, Office of Water Regulations and Standards.
U.S. EPA. 1988. Interim sediment criteria values for nonpolar hydrophobic organic compounds.
U.S. Environmental Protection Agency, Office of Water, Criteria and Standards Division.
U.S. EPA. 1991. Record of decision: Sullivan's Ledge site, Middle Marsh Operable Unit, New
Bedford, Massachusetts. U.S. Environmental Protection Agency, Region 2.
U.S. FWS. 1980. Habitat evaluation procedures (HEP) ESAM 102. U.S. Fish and Wildlife
Service, Division of Ecological Services.
8/93 37 Case Study
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
MAR 25 1991
OFFICE OF
SOLID WASTE AND EMERGENCY RESPONSE
MEMORANDUM
SUBJECT:
FROM:
OSWER Directive 9285.6-03
Human Health"'Evaluation Manual, Supplemental quidance:
"Standard Default Exposure Factors"
Timothy Fields, Jr., Acting Director
Office of Emergency and RemedJ^al^Response
Bruce Diamond, Direct
Office of Waste Programs
forcement
TO:
Director, Waste Management Division,
Regions I, IV, V, & VII
Director, Emergency & Remedial Response Division,
Region II
Director, Hazardous Waste Management Division,
Regions III, VI, VIII, & IX
Director, Hazardous Waste Division,
Region X
Purpose
The purpose of this directive is to transmit the Interim
Final Standard Exposure Factors guidance to be used in the
remedial investigation and feasibility study process. This
guidance supplements the Risk Assessment Guidance for Superfund:
Human Health Evaluation Manual, Part A that was issued
October 13, 1989.
Background
An intra-agency workgroup was formed in March 1990 to
address concerns regarding inconsistencies among the exposure
assumptions used in Superfund risk assessments. Its efforts
resulted in a June 29, 1990, draft document entitled "Standard
Exposure Assumptions". The draft was circulated to both
technical and management staff across EPA Regional Offices and
within Headquarters. It was also discussed at two EPA-sponsored
meetings in the Washington, D.C., area. The attached interim
final document reflects the comments received as well as the
results of recent literature reviews addressing inhalation rates,
soil ingestion rates and exposure frequency estimates.
Printed on Recycled Paper
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Ob-iective
This guidance has been developed to reduce unwarranted
variability in the exposure assumptions used by Regional
Superfund staff to characterize exposures to human populations in
the baseline risk assessment.
Implementation
This guidance supplements the Risk Assessment Guidance for
Superfund (RAGS): Human Health Evaluation Manual, Part A. Where
numerical values differ from those presented in Part A/ the
factors presented in this guidance supersede those presented in
Part A.
This guidance is being distributed as an additional interim
final guidance in the RAGS series. As new data become available
and the results of EPA-sponsored research projects are finalized,
this guidance will be modified accordingly. We strongly urge
Regional risk assessors to contact the Toxics Integration Branch
of the Office of Emergency and Remedial Response (FTS 475-9486)
with any suggestions for further improvement; as we will begin
updating and consolidating the series of RAGS documents in 1992.
Attachment
cc: Regional Branch Chiefs
Regional Section Chiefs
Regional Toxics Integration Coordinators
Workgroup Members
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ACKNOWLEDGEMENTS
This guidance was developed by the Toxics Integration Branch
(TIB) of EPA's Office of Emergency and Remedial Response,
Hazardous Site Evaluation Division. Janine Dinan of TIB provided
overall project management and technical coordination in the
later stages of its development under the direction of Bruce
Means, Chief of TIB's Health Effects Program.
TIB would like t;o acknowledge the efforts of the interagency work
group chaired by Anne Sergeant of EPA's Exposure Assessment Group
in the Office of Health and Environmental Assessment. Workgroup
members, listed below, and Regional staff provided valuable input
regarding the content and scope of the guidance.
Glen Adams, Region IV
Lisa Askari, Office of Solid Waste
Alison Barry, OERR/HSCD
Steve Caldwell, OERR/HSED
David Cooper, OERR/HSCD
Linda Cullen, New Jersey Department of Environmental Protection
Steve Ells, OWPE/CED
Kevin Garrahan, OHEA/EAG
Susan Griffin, OERR/TIB
Gerry Hiatt, Region IX
Russ Kinerson, OHEA/EAG
Jim LaVelle, Region VIII
Mark Mercer, OERR/HSCD
Sue Norton, OHEA/EAG
Andrew Podowski, Region V
John Schaum, OHEA/EAG
Leigh Woodruff, Region X
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TABLE OF CONTENTS
Page
1.0 Introduction 1
1.1 Background 2
1.2 Present and Future
Land Use Considerations 3
2.0 Residential 5
2.1 Ingestion of Potable Water 5
2.2 Incidental Ingestion of
Soil and Dust 6
2.3 Inhalation of Contaminated
Air 6
2.4 Consumption of Homegrown
Produce 7
2.5 Subsistence Fishing 8
3.0 Commercial/Industrial 9
3.1 Ingestion of Potable Water 9
3.2 Incidental Ingestion of
Soil and Dust 9
3.3 Inhalation of Contaminated
Air 10
4.0 Agricultural 10
4.1 Farm Family Scenario 10
4.1.1 Consumption of Homegrown
Produce 11
4.1.2 Consumption of Animal
Products 11
4.2 Farm Worker 12
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5.0 Recreational 12
5.1 Consumption of Locally
Caught Fish 12
5.2 Additional Recreational
Scenarios 13
6.0 Summary 14
7.0 References 16
Attachment A
Attachment B
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OSWER DIRECTIVE: 9285.6-03
March 25, 1991
RISK ASSESSMENT GUIDANCE FOR SUPERFUND
VOLUME I: HUMAN HEALTH EVALUATION MANUAL
SUPPLEMENTAL GUIDANCE
"STANDARD DEFAULT EXPOSURE FACTORS"
INTERIM FINAL
Office of Emergency and Remedial Response
Toxics Integration Branch
•U.S. Environmental Protection Agency
Washington, D.C. 20460
(202)475-9486
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* * * * NOTICE * * * *
The policies set out in this document are not final Agency
action, but are intended solely as guidance. They are not
intended, nor can they be relied upon, to create any rights
enforceable by any party in litigation with the United States.
EPA officials may decide to follow the guidance provided in this
document, or to act at variance with the guidance, based on an
analysis of site-specific circumstances. The Agency also
reserves the right to modify this guidance at any time without
public notice.
************
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1.0 INTRODUCTION
The Risk Assessment Guidance for Superfund (RAGS) has been
divided into several parts. Part A, of the Human Health
Evaluation Manual (HHEM; U.S. EPA, 1989a), is the guidance for
preparing baseline human health risk assessments at Superfund
sites. Part B, now in draft form, will provide guidance on
calculating risk-based clean-up goals. Part C, still in the
early stages of development, will address the risks associated
with various remedial actions.
The processes outlined in these guidance manuals are a positive
step toward achieving national consistency in evaluating site
risks and setting goals for site clean-up. However, the
potential for inconsistency across Regions and among sites still
remains; both in estimating contaminant concentrations in
environmental media and in describing characteristics and
behaviors of the exposed populations.
Separate guidance on calculating contaminant concentrations is
currently being developed in response to a number of inquiries
from both inside and outside the Agency. The best method for
calculating the reasonable maximum exposure (RME) concentration
for different media has been subject to a variety of
interpretations and is considered an important area where further
guidance is needed.
This supplemental guidance attempts to reduce unwarranted
variability in the exposure assumptions used to characterize
potentially exposed populations in the baseline risk assessment.
This guidance builds on the technical concepts discussed in HHEM
Part A and should be used in conjunction with Part A. However,
where exposure factors differ, values presented in this guidance
supersede those presented in HHEM Part A.
Inconsistencies among exposure assumptions can arise from
different sources: 1) where risk assessors use factors derived
from site-specific data; 2) where assessors must use their best
professional judgement to choose from a range of factors
published in the open literature; and 3) where assessors must
make assumptions (and choose values) based on extremely limited
data. Part A encourages the use of site-specific data so that
risks can be evaluated on a case-by-case basis. This
supplemental guidance has been developed to encourage a
consistent approach to assessing exposures when there is a lack
of site-specific data or consensus on which parameter value to
choose, given a range of possibilities. Accordingly, the
exposure factors presented in this document are generally
considered most appropriate and should'be used in baseline risk
assessments unless alternate or site-specific values can be
clearly justified by supporting data.
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Supporting data for many of the parameters presented in this
guidance can be found in the Exposure Factors Handbook (EFH; U.S.
EPA, 1990). In cases where parameter values are not available in
EFH, this guidance adopts well-quantified or widely-accepted data
from the open literature. Finally, for factors where there is a
great deal of uncertainty, a rationally-derived, cons»rvative
estimate is developed and explained. As new data become
available, this guidance will be modified to reflect them.
These standard factors are intended to be used for calculating
reasonable maximum exposure (RME) estimates for each epplicable
scenario at a site. Readers are reminded that the goal of RME is
to combine upper-bound and mid-range exposure factors in the
following equation so that the result represents an exposure
scenario that is both protective and reasonable; not the worst
possible case:
Intake = c x IR x EF x ED
BW x AT
C = Concentration of the chemical in each medium
(conservative estimate of the media average
contacted over the exposure period)
IR = Intake/Contact Rate (upper-bound value)
i
EF = Exposure Frequency (upper-bound value)
ED = Exposure Duration (upper-bound value)
BW = Body Weight (average value)
AT = Averaging Time (equal to exposure duration for
non-carcinogens and 70 years for carcinogens)
Please note that the Agency is presently evaluating methods for
calculating conservative exposure estimates, such as RME, in
terms of which parameters should be upper-bound or mid-range
values. If warranted, this guidance will be modified
accordingly.
1.1 BACKGROUND
An intra-agency workgroup was formed at the Superfund Health Risk
Assessment meeting in Albuquerque, New Mexico (February 26 -
March 1, 1990)'. Its efforts resulted in a June 29, 1990, draft
document entitled "Standard Exposure Assumptions". The draft was
distributed to Superfund Regional Branch Chiefs, and members of
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other programs within the Agency, for their review and comment.
It was also presented and discussed at two EPA/OERR sponsored
meetings. The meetings, facilitated by Clean Sites, Inc.,
brought members of the "Superfund community" and the Agency
together to focus on technical issues in risk assessment.
A final review draft was distributed on December 5, 1990, 'which
reflected earlier comments received as well as the results of
more recent literature reviews addressing inhalation rates, soil
ingestion rates and exposure frequency estimates (these being
areas commented on most frequently).
1.2 PRESENT AND FUTURE LAND USE CONSIDERATIONS
The exposure scenarios, presented in this document, and their
corresponding assumptions have been developed.within the context
of the following land use classifications: residential,
commercial/industrial, agricultural or recreational.
Unfortunately, it is not always easy to determine actual land use
or predict future use: local zoning may not adequately describe
land use; and unanticipated or even planned rezoning actions can
be difficult to assess. Also, the definition of these zones can
differ substantially from region to region. Thus, for the
purposes of this document, the following definitions are used:
Residential
Residential exposure scenarios and assumptions should be
used whenever there are or may be 'occupied residences on or
adjacent to the site. Under this land use, residents are
expected to be in frequent, repeated contact with
contaminated media. The contamination may be on the site
itself or may have migrated from it. The assumptions in
this case account for daily exposure over the long term and
generally result in the highest potential exposures and
risk.
Commercial/Industrial
Under this type of land use, workers are exposed to
contaminants within a commercial area or industrial site.
These scenarios apply to those individuals who work on or
near the site. Under this land use, workers are expected to
be routinely exposed to contaminated media. Exposure may be
lower than that under the residential scenarios, because it
is generally assumed that exposure is limited to 8 hours a
day for 250 days per year.
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Agricultural
These scenarios address exposure to people who live on the
property (i.e., the farm family) and agricultural workers.
Assumptions made for worker exposures under the
commercial/industrial land use may not be applicable to
agricultural workers due to differences in workday length,
seasonal changes in work habits, and whether migrant workers
are employed in the affected area. Finally, the farm family
scenario should be evaluated only if it is known that such
families reside in the area.
Recreational
This land use addresses exposure to people who spend a
limited amount of time at or near a site while playing,
fishing, hunting, hiking, or engaging in other outdoor
activities. This includes what is often described as the
"trespasser" or "site visitor" scenario. Because not all
sites provide the same opportunities/ recreational scenarios
must be developed on a site-specific basis. Frequently, the
community surrounding the site can be an excellent source of
information regarding the current and potential recreational
use of a site. The RPM/risk assessor is encouraged to
consult with local groups to collect this type of
information.
In the case of trespassers, current exposures are likely to
be higher at inactive sites than at active sites because
there is .generally little supervision of abandoned
facilities. At most active sites, security patrols and
normal maintenance of barriers such as fences tend to limit
(if not entirely prevent) trespassing. When modeling
potential future exposures in the baseline risk assessment,
however, existing fences should not be considered a
deterrent to future site access.
Recreational exposure should account for hunting and fishing
seasons where appropriate, but should not disregard local
reports of species taken illegally. Other activities should
also be scaled according to the amount of time they could
actually occur; for children and teenagers, the length of
the school year can provide a helpful limit when evaluating
the frequency and duration of certain outdoor exposures.
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2.0 RESIDENTIAL
Scenarios for this land use should be evaluated whenever there
are homes on or near the site, or when residential development is
reasonably expected in the future. In determining the potential
for future residential land use, the RPM should consider:
historical land use; suitability for residential development;
local zoning; and land use trends. Exposure pathways evaluated
under this scenario routinely include, but may not be limited to:
ingestion of potable water; incidental ingestion of soil and
dust; inhalation of contaminated air; and, where appropriate,
consumption of home grown produce.
2.1 Inaestion of Potable Water
This pathway assumes that adult residents consume 2 liters
of water per day, 350 days per year, for 30 years.
The value of 2 liters per day for drinking water is
currently used by the Office of Water in setting drinking
water standards. It was originally used by the military to
calculate tank truck requirements. In addition, 2 liters
happens to be quite close to the 90th percentile for
drinking water ingestion (U.S. EPA, 1990), and is
comparable to the 8 glasses of water per day historically
recommended by health authorities.
The exposure frequency (EF) of 365 days/year for the
residential setting used in RAGS Part A has been argued both
inside and outside of the Agency as being too conservative
for RME estimates. National travel data were reviewed to
determine if an accurate number of "days spent at home"
could be calculated.' Unfortunately, conclusions could not
be drawn from the available literature; as it presents data
on the duration of trips taken for pleasure, but not the
frequency of such trips (OECD, 1989; Goeldner and Duea,
1984; National Travel Survey, 1982-89). However, the
Superfund program is committed to moving away from values
that represent the "worst possible case." Thus, until
better data become available, the common assumption that
workers take two weeks of vacation per year can be used to
support a value of 15 days per year spent away from home
(i.e., 350 days/year spent at home).
In terms of exposure duration (ED), the resident is assumed
to live in the same home for 30 years. In the EFH, this
value is presented as the 90th-percentile for time spent at
one residence. (Please note that in the intake equation,
averaging time (AT) for exposure to non-carcinogenic
compounds is always equal to ED; whereas, for carcinogens a
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70 year AT is still used in order to compare to Agency slope
factors typically based on that value).
2.2 Incidental Inaestion of Soil and Dust
The combined soil and dust ingestion rates used in this
document were presented in OSWER Directive 9850.4 (U.S. EPA,
1989b), which specifies 200 mg per day for children aged 1
thru 6 (6 years of exposure) and 100 mg per day for others.
These factors account for ingestion of both outdoor soil and
indoor dust and are believed to represent upper-bound values
for soil'and dust ingestion (Calabrese, et al., 1989;
Calabrese, et al., 1990a,b; Davis, et al., 1990; Van Wijnen,
et al., 1990). Presently, there is no widely a'ccepted
method for determining the relative contribution of each
medium (i.e., soil vs. dust) to these daily totals, and the
effect of climatic variations (e.g., snow cover) on these
values has yet to be determined. Thus, a constant, year
round exposure is assumed (i.e., 350 days/year).
Please note that the equation for calculating a 30-year
residential exposure to soil/dust is divided into two parts.
First, a six-year exposure duration is evaluated for young
children which accounts for the period of highest soil
ingestion (200 mg/day) and lowest body weight (15 kg).
Second, a 24-year exposure duration is assessed for older
children and adults by using a lower soil ingestion rate
(100 mg/day) and an adult body weight (70 kg).
2.3 Inhalation of Contaminated Air
In response to a number of comments, the RME inhalation rate
for adults of 30 m /day (presented in HHEM Part A) was re-
evaluated. Activity-specific inhalation rates were combined
with time-use/activity level data to derive daily inhalation
rate values (see Attachment A). Our evaluation focused on
the following population subgroups who would be expected to
spend the majority of their time at home: housewives;
service and household workers; retired people; and
unemployed workers (U.S. EPA, 1985). An inhalation rate of
20 m /day was found to represent a reasonable upper-bound
value for adults in these groups. This value was derived by
combining inhalation rates for indoor and outdoor activities
in the residential setting. This rate would be used in
conjunction with ambient air levels measured at or downwind
of the site. Although sampling data are preferred,
procedure^ described in Hwang and Falco (1986) and
Cowherd, et al. (1985) can be used to estimate volatile and
dust-bound contaminant concentrations, respectively.
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In cases where the residential water supply is contaminated
with volatiles, the assessor needs to consider the potential
for exposure during household water use (e.g. , cooking,
laundry, bathing and showering). Using the same time-
use/activity level data described above, a total of
15 m /day was found to represent a reasonable upper-bound
inhalation rate for daily, indoor, residential activities.
Methods for modeling volatilization of contaminants in the
household (including the shower) are currently being
developed by J.B. Andelman and U.S. EPA's Exposure
Assessment Group. Assessors should contact the Superfund
Health Risk Assessment Technical Support Center for help
with site-specific evaluations (FTS-684-7300).
2.4 Consumption of Home Grown Produce
This pathway need not be evaluated for all sites. It may
only be relevant for a small number of compounds (e.g., some
inorganics and pesticides) and should be evaluated when the
assessor has site-specific information to support this as a
pathway of concern for the residential setting.
The EFH presents figures for "typical" consumption of fruit
(140 g/day) and vegetables (200 g/day) with the "reasonable
worst case" proportion of produce that is homegrown as 30
and 40 percent, respectively. This corresponds to values of
42 g/day for consumption of homegrown fruit and 80 g/day for
homegrown vegetables. They are derived from data in Pao, et
al. (1982) and USDA (1980). EFH also provides data on
consumption of specific homegrown fruits and vegetables that
may be more appropriate for site-specific evaluations.
Although sampling data are much preferred, in their absence
plant uptake of certain organic compounds can be estimated
using the procedure described in Briggs, et al. (1982). No
particular procedure is recommended for quantitatively
assessing inorganic uptake at this time; however, the
following table developed by Sauerbeck (1988) provides a
qualitative guide for assessing heavy metal uptake into a
number of plants:
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High
lettuce
spinach
carrot
endive
cress
beet and
beet leaves
Plant Uptake of Heavy Metals
Moderate Low
onion
mustard
potato
radish
corn
cauliflower
asparagus
celery
berries
Very Low
beans
peas
melon
tomatoes
fruit
2.5 Subsistence Fishing
This pathway is not expected to be relevant for most sites.
In order to add subsistence fishing as a pathway of concern
among the residential scenarios, onsite contamination must
have impacted a water body large enough to produce a
consistent supply of edible fish, and there must be evidence
that area residents regularly fish in this water body (e.g.,
interviews with local anglers). If these criteria are met,
the 95th-percentile for daily fish consumption (132 g/day)
from Pao, et al. (1982) should be used to represent the
ingestion rate for subsistence fishermen. This value was
derived from a 3-day study of people who ate fish, other
than canned, dried, or raw. An example of this consumption
rate is about four 8-ounce servings per week.
This consumption rate can also be used to evaluate exposures
to non-residents who may also use the water body for
subsistence fishing. In this case, the exposure estimate
would not be added to estimates calculated for other
residential pathways, but may be included in the risk
assessment as an exposure pathway for a sensitive sub-
population.
For further information regarding food chain contamination the
assessor is directed to the following documents:
o Methodology for Assessing Health Risks Associated with
Indirect Exposures to Combustor Emissions (PB-90-
187055). Available through NTIS. '
o Development of Risk Assessment 'Methodology for Land
Application and Distribution and Marketing of Municipal
Sludge (EPA/600/6-89/001). Available from
OHEA/Technical Information at FTS 382-7326.
o Estimating Exposure to 2,3,7,8-TCDD (EPA/600/6-
88/005A). Available from OHEA/Technical Information at
FTS 382-7326.
8
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3.0 COMMERCIAL/INDUSTRIAL
Occupational scenarios should be evaluated when land use is (or
is expected to be) commercial/industrial. In general, these
scenarios address a 70-kg adult who is at work 5 days a week for
50 weeks per year (250 days total). The individual is assumed to
work 25 years at the same location (95th-percentile; Bureau of
Labor Statistics, 1990). This scenario also considers ingestion
of potable water, incidental ingestion of soil and dust, and
inhalation of contaminated air.
Please note that under mixed-use zoning (e.g., apartments above
storefronts), certain pathways described for the residential
setting should also be evaluated.
3.1 Inaestion of Potable Water
Until data become available for this pathway, it will be
assumed that half of an individual's daily water intake
(1 liter out of 2) occurs at work. All water ingested is
assumed to come from the contaminated drinking water source
(i.e., bottled water is not considered). For site-specific
cases where workers are known to consume considerably more
water (e.g., those who work outdoors in hot weather or in
other high-activity/stress environments), it may be
necessary to adjust this figure.
A lower ingestion rate is used in this pathway so that a
more reasonable exposure estimate may be made for workers
ingesting contaminated water. However, it is important to
remember that remedial actions are often based on returning
the contaminated aquifer to maximum beneficial use; which
generally means achieving levels suitable for residential
use.
3.2 Incidental Inqestion of Soil and Dust
In the occupational setting, incidental ingestion of soil
and dust is highly dependent on the type of work being
performed. Office workers would be expected to contact much
less soil and dust than someone engaged in outdoor work such
as construction or landscaping. Although no studies were
found that specifically measured the amount of soil ingested
by workers in the occupational setting, the one study that
measured adult soil ingestion included subjects that worked
outside of the home (Calabrese, et al., 1990a). Although
the study had a limited number of subjects (n=6) and did not
associate the findings with any particular activity pattern,
it is the only study that did not rely on modeling to
-------
estimate adult soil ingestion. Thus, the Calabrese, et al.
(1990a) estimate of 50 ing/day is selected as an interim
default for adult ingestion of soil and dust in the
"typical" workplace. Please be aware that this value may
change when the results of ongoing soil ingestion studies
sponsored by EPA's Exposure Assessment Group are finalized
in 1991.
Attachment B presents modeled rates for adult soil ingestion
that should be used to estimate exposures for certain
workplace activities where much greater soil contact is
anticipated, but with limited exposure frequency and/or
duration.
3.3 Inhalation of Contaminated Air
As in the previous discussion regarding inhalation rates
for the residential setting, specific time-use/activity
level data were used to estimate inhalation rates for
various occupational activities. The results indicate that
20 m per 8-hour workday represents a reasonable upper-
bound inhalation rate for the occupational setting (see
Attachment A). Although analytical data are much preferred,
procedures described in Hwang and Falco (1986) and Cowherd,
et al. (1985) can be used to estimate volatile and dust-
bound contaminant concentrations, respectively.
4.0 AGRICULTURAL
These land use scenarios include potential exposures for farm
families living and working on the site, as well as, individuals
who may only be employed as farm workers.
4.1 Farm Family Scenario
This scenario should be evaluated only if it is known or
suspected that there are farm families in the area. The
animal products pathway should not be used for areas zoned
residential, because such regulations generally prohibit the
keeping of livestock. Farm family members are assumed to
have most of the same characteristics as people in the
residential setting; the only difference is that consumption
of homegrown produce will always be evaluated. Thus,
default values for the soil ingestion, drinking water, and
inhalation pathways would be the same as those in the
residential setting.
10
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4.1.1 Consumption of Homegrown Produce
The values used in evaluating this pathway are the same
as those presented in Section 2.4. While it is more
likely for farm families to cultivate fruits and
vegetables, it is not necessarily true that they would
be able to grow a sufficient variety to meet all their
dietary needs and tastes. Thus, the consumption rate
default values will be 42 g/day and 80 g/day for fruits
and vegetables, respectively. Again, EFH presents
consumption rates for specific homegrown fruits and
vegetables. The assessor is reminded that the plant
uptake pathway is not relevant for all contaminants and
sampling of fruits and vegetables is highly
recommended. However, in the absence of analytical
data, plant uptake of organic chemicals can be '
estimated using the procedure described in Briggs, et
al. (1982). No particular procedure is recommended for
quantitatively assessing inorganic uptake at this time;
however, the table (presented in Section 2.4) developed
by Sauerbeck (1988) provides a qualitative guide for
assessing heavy metal uptake into a number of plants.
4.1.2 Consumption of Animal Products
Animal products should only be addressed if it is known
that local residents produce them for home consumption
or are expected to do so in the future. The best way
to determine which items are produced is by interviews
or consultation with the local County Extension Service
which usually has data on the type and quantity of
local farm products.
EFH provides average ingestion rates for beef and dairy
products and assumes that the farm family produces
75 percent of what it consumes from these categories.
This corresponds to a "reasonable worst case"
consumption rate of 75 g/day for beef and 300 g/day for
dairy products. Although sampling data are much
preferred, in their absence the procedure described in
Travis and Arms (1988) may be used to estimate organic
contaminant concentrations in beef and milk. This
procedure does not provide transfer coefficients for
poultry and eggs. Thus, the latter two pathways can be
evaluated only if site-specific concentrations for
poultry and eggs are available, or if transfer
coefficients can be obtained from the literature.
Additional references addressing potential exposures from
contaminated foods are listed in Section 2.0.
11
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4.2 Farm Worker
Many farm activities, such as plowing and harrowing, can
generate a great deal of dust. The risk assessor should
consider the effects of observed (or expected) agricultural
practices when using the fugitive dust model suggested under
the residential scenario. Note that soil ingestion rate may
be similar to the outdoor yardwork scenario discussed in
Attachment B, although it will be necessary to modify the
exposure frequency and duration to account for climate and
length of employment. The local County Extension Service
should be able to provide information on agricultural
practices around a site. In addition, the Biological and
Economic Analysis Division in the Office of Pesticide
Programs maintains a database of the usual planting and
harvesting dates for a number of crops in most U.S. states.
This information may be very helpful for estimating times of
peak exposure for farm workers, and, if needed, can be
obtained through the Superfund Health Risk Assessment
Technical Support Center (FTS 684-7300) .
5.0 RECREATIONAL
As stated previously, sites present different opportunities for
recreational activities. The RPM or risk assessor is encouraged
to consult with the local community to determine whether there is
or could be recreational use of the property along with the
likely frequency and duration of any activities.
5.1 Consumption of Locally Caught Fish
This pathway should be evaluated when there is access to a
contaminated water body large enough to produce a consistent
supply of edible-sized fish over the anticipated exposure
period. Although the local authorities should know if the
water body is used for fishing, illegal access (trespassing)
and deliberate disregard of fishing bans should not
necessarily be ruled out; the risk assessor should check for
evidence of these activities. If required, the scenario can
be modified to account for fishing season, type of edible
fish available, consumption habits, etc.
For recreational fishing, the average consumption rate of
54 g/day from Pao, et al. (1982) is used. This value is
derived from a 3-day study of people who ate finfish, other
than canned, dried or raw. An example of this consumption
rate is about two 8-ounce servings per week. Other values
presented in EFH, for consumption of recreationally caught
fish, are from limited studies of fishermen on the west
coast and may not be applicable to catches in other areas.
12
-------
When evaluating this pathway please consider the possibility
of subsistence fishing. Unlike the residential scenario,
exposure estimates from this pathway would not necessarily
be added to any other exposure estimates (see Section 2-5).
Instead, it would be included as an estimate of exposure for
a sensitive sub-population.
5.2 Additional Recreational Scenarios
A number of commentors requested standard default values for
the following recreational scenarios: hunting, dirtbiklng,
swimming and wading. One approach to address exposure
during swimming and wading is presented in HHEM Part A, The
Agency is currently involved in research projects designed
to estimate dermal uptake of contaminants from soil, wster
and sediment. Results of these studies will be used to
update the swimming and wading scenarios as well as other
scenarios that rely on estimates of dermal absorption.
Unfortunately, lack of data and problems in estimating
exposure frequencies and durations based on regional
variations in climate have precluded the standardization of
other recreational scenarios at this time. Additional
guidance will be developed as data become available.
13
-------
6. 0 SUMMARY
This supplemental guidance has been developed to provide a
standard set of default values for use in exposure assessments
when site-specific data are lacking. These standard factors are
intended to be used for calculating reasonable maximum exposure
(RME) levels for each applicable land use scenario at a site.
Supporting data for many of the assumptions can be found in the
Exposure Factors Handbook (EFH; U.S. EPA, 1990). When supporting
information was not available in EFH, well-quantified or .widely-
accepted data from the open literature were adopted. Finally,
for factors where there is a great deal of uncertainty, a
rationally conservative estimate was developed and explained.
As new data become available, either for the factors themselves
or for calculating RME, this guidance will z>e modified
accordingly.
The following table summarizes the exposure pathways that will be
evaluated on a routine basis for each land use, and the current
default values for each exposure parameter in the standard intake
equation presented below (refer to HHEM: Part A, U.S. EPA, 1989a,
for a more detailed discussion of each exposure parameter):
Intake = C x IR x EF x ED
BW x AT
C = Concentration of the chemical in each medium
IR = Intake/Contact Rate
EF = Exposure Frequency
ED = Exposure Duration
BW = Body Weight
AT = Averaging Time
14
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7.0 REFERENCES
Briggs, G., R. Bromilow, and A. Evans. 1982. Relationship
between lipophilicity and root uptake and translocation of
non-ionized chemicals by barley. Pesticide Science 13:495-
504.
Bureau of Labor Statistics. 1990. Statistical summary: tenure
with current employer as of January 1987. (Transmitted via
facsimile, 7 September 1990)
Calabrese, E.J., Barnes, R., Stanek, E.J., Pastides, H.,
Gilbert, C.E., Veneman, P., Wang, X., Lasztity, A., and P.T.
Kosteck. 1989. How Much Soil Do Y.oung Children Ingest: An
Epidemiologic Study. Reg. Tox. and Pharmac. 10:12?-137.
Calabrese, E.J., Stanek, E.J., Gilbert, C.E.,and R.M. Barnes.
1990a. Preliminary Adult Soil Ingestion Estimates: Results
of a Pilot Study. Reg. Tox. and Pharmac. 12:88-95.
Calabrese, E.J. 1990b. Personal communication with J. Dinan,
Toxics Integration Branch. EPA/OSWER/OERR. October 24,
1990.
Cowherd, C., Muleski, G., Englehart, P., and D. Gillette. 1985.
Rapid Assessment of Exposure to Particulate Emissions from
Surface Contamination. Prepared by Midwest Research
Institute, Washington, D.C. for EPA/OHEA. EPA-600/8-85-002.
Davis, S., Waller, P., Buschbom, R., Ballou, J. and P. White.
1990. Quantitative Estimates of Soil Ingestion in Normal
Children between the Ages of 2 and 7 Years: Population-
based Estimates Using Aluminum, Silicon and Titanium as Soil
Tracer Elements. Arc. Environ. Health. 45(2):112-122.
Goeldner, C.R. and K.P. Duea. 1984. Travel Trends in the United
States and Canada. Business Research Division, University
of Colorado at Boulder.
Hawley, J.K. 1985. Assessment of health risk from exposure to
contaminated soil. Risk Analysis 5(4):289-302.
Hwang, S.T., and J.W. Falco. 1986. Estimation of Multimedia
Exposures Related to Hazardous Waste Facilities. In: Cohen
(ed.). Pollutants in a Multimedia Environment. New York, NY:
Plenum Publishing Corp. pp. 229-264.
National Travel Survey. 1982-1989. U.S. Travel Data Center,
Washington, D.C.
16
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OECD. 1989. National and International Tourism Statistics,
1974-1985. Organization for Economic Cooperation and
Development.
Pao, E.M., K.H. Fleming, P.A. Guenther, and S.J. Mickle. 1982.
Foods commonly eaten by individuals: Amounts per day and per
eating occasion. USDA, Human Nutrition Information Service.
Home Economics Report No. 44.
Sauerbach, D. 1988. Transfer of Heavy Metals in Plants. As
published in: Technical Report No. 40, Hazard Assessment of
Chemical Contaminants in Soil (August 1990). European
Chemical Industry Ecology & Toxicology Centre. Brussels,
Belgium. ISSN-0773-8072-40
Travis, C.C. and A.D. Arms. 1988. Bioconcentration of organics
in beef, milk, and vegetation. Environmental Science and
Technology 22(3):271-274.
U.S. Department of Agriculture. 1980. Food and nutrient intakes
of individuals in one day in the United States, Spring 1977.
Nationwide Food Consumption Survey 1977-1978. Preliminary
Report No. 2.
U.S. Environmental Protection Agency. 1990. Exposure Factors
Handbook. Office of Health and Environmental Assessment.
EPA/600/8-89/043, March 1990.
U.S. Environmental Protection Agency. 1989a. Risk Assessment
Guidance for Superfund, Volume I: Human Health Evaluation
Manual. Office of Emergency and Remedial Response.
EPA/540/1-89/002.
U.S. Environmental Protection Agency. 1989b. Interim Final
Guidance for Soil Ingestion. Office of Solid Waste and
Emergency Response. OSWER Directive 9850.4.
U.S. Environmental Protection Agency. 1985. Development of
Statistical Distributions of Ranges of Standard Factors Used
in Exposure Assessments. OHEA-E-161, March 1985.
Van Wijnen, J.H., Clausing, P. and B. Brunekreef. 1990.
Estimated Soil Ingestion by Children. Environmental
Research 51: 147-162.
17
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ATTACHMENT A
ACTIVITY SPECIFIC INHALATION RATES
Background
The standard default value of 20 m3/day has been used by EPA to
represent an average daily inhalation rate for adults. According
to EFH, this value was developed by the International Commission
on Radiologic Protection (ICRP) to represent a daily inhalation
rate for "reference man" engaged in 16 hours of "light activity"
and 8 hours of "rest". EPA (1985) reported on a similar study
that indicated the average inhalation rate for a man engaged in
the same activities would be closer to 13 m /day. EFH, in turn,
reiterated the findings of ICRP and EPA (1985) then calculated a
"reasonable worst case" inhalation rate of 30 m3/day. This
reasonable worst case value was used in Part A of the Human
Health Evaluation Manual as the RME inhalation rate for
residential exposures.
Commentors from both inside and outside the Agency expressed
concerns that this value may be too conservative. Many also
added their concern that exposure values calculated using this
inhalation rate would not be comparable to reference doses (RfD)
and cancer potency factors (gl*) values based on an inhalation
rate of 20 m /day. Thus, the Toxics Integration Branch of
Superfund (TIB) conducted a review of the literature to determine
the validity of using 30 m /day as the RME inhalation rate for
adults. Members of EPA's Environmental Criteria Assessment
Office-Research Triangle Park (A. Jarabek, 9/20/90) and the
Science Advisory Board (10/26/90) have suggested that inhalation
rates could be calculated using time-use/activity level data
reported in the "Development of Statistical Distributions or
Ranges of Standard Factors Used in Exposure Assessments" (OHEA;
U.S. EPA, 1985). Thus, TIB used this data to calculate an RME
inhalation rate for both the residential and occupational
settings, as follows.
Methodology
The time-use/activity level1 data reported by OHEA
(1985) were analyzed for each occupation subgroup;
The data were divided into hours spent at home vs.
hours' spent at the workplace (lunch hours spent outside
of work and hours spent in transit were excluded);
The hourly data were subdivided into hours spent
indoors vs. outdoors (to allow for estimating exposures
to'volatile contaminants during indoor use of potable
water);
-------
ATTACHMENT B
ESTIMATING ADULT SOIL INGESTION
IN THE COMMERCIAL/INDUSTRIAL SETTING
Most of the available soil ingestion studies focus on children in
the residential setting; however, two studies were found that
address adult soil ingestion that also have application to the
commercial/industrial setting (Hawley, 1985; Calabrese, et al.,
1990).
Hawley (1985) used a number of assumptions for contact rates and
body surface area to estimate the amount of soil and dust adults
may ingest during a variety of residential activities. For
indoor exposures, Hawley estimated levels based on contact with
soil/dust in two different household areas, as follows:
0.5 mg/day for daily exposure in the "living space"; and 110
mg/day for cleaning dusty areas such as attics or basements. For
outdoor exposures, Hawley estimated a soil ingestion rate during
yardwork of 480 mg/day. The assumptions used to model exposures
in the residential setting may also be applied to similar
situations in the workplace. The amount of soil and dust adults
contact in their houses may be similar to the 'amount an office or
indoor maintenance worker would be expected to contact.
Likewise, the amount of soil contacted by someone engaged in
construction or landscaping may be more analogous to a resident
doing outdoor yardwork.
Calabrese, et al. (1990) conducted a pilot study that measured
adult soil ingestion at 50 mg/day. Although the study has
several drawbacks (e.g., a limited number of participants and no
information on the participants daily work activities), it
included subjects that worked outside the home. It is also
interesting to note that this measured value falls within the
range Hawley (1985) estimated for adult soil ingestion during
indoor activities.
From these studies, 50 mg/day was chosen as the standard default
value for adult soil ingestion in the workplace. It was chosen
primarily because it is a measured value but also because it
falls within the range of modeled values representing two widely
different indoor exposure scenarios. The 50 mg/day value is to
be used in conjunction with an exposure frequency of 250
days/year and an exposure duration of 25 years. For certain
outdoor activities in the commercial/industrial setting (e.g.,
construction or landscaping), a soil ingestion rate of 480 mg/day
may be used; however, this type of work is usually short-term and
is often dictated by the weather. Thus, exposure frequency would
generally be less than one year and exposure duration would vary
according to site-specific construction/maintenance plans.
-------
The corresponding activity level was assigned to c-fccb
hour and the total number of hours spent at each
activity level was calculated;
For time spent inside the home, 8 hours per day were
assumed to be spent at rest; and
The total number of hours spent at each activity level
was multiplied by average inhalation rates reported in
the EFH. flote; average values were used since only
minimum, maximum and average values were reported, The
use of maximum values would have to be considered
"worst case". Values for average adults were applied
to all but the housewife data (where average rates for
women were applied).
The results showed that the highest weekly inhalation rate was
18.3 m /day for the residential setting and 18 m /day for the
workplace. These values represent the highest .among the weekly
averages and were derived from coupling "worst case" activity
patterns with "average" adult inhalation rates. It was concluded
from these data that 30 m /day may in fact be too conservative
and that 20 m3,/day would be more representative of a reasonably
conservative inhalation rate for total (i.e., indoor plus
outdoor) exposures at home and in the workplace.
RAGS Part B will specifically model exposure to volatile organics
via indoor use of potable water. Using the method described
previously, it was determined that 15 m /day would represent a
reasonably conservative inhalation rate for indoor residential
exposures.
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PB92-963373
United States
Environmental Protection
Agency
Office of SoW Waste and
Washington, O.C. 20460
Publication 9265.7-081
May 1992
Supplemental Guidance to
RAGS: Calculating the
Concentration Term
Office of Emergency and Remedal Response
Hazardous Site Evaluation Division, OS-230
Intermittent Bulletin
Volume 1 Number 1
The overarching mandate of the Comprehensive Environmental Response, Compensation, and Liability
Act (CERCLA) is to protect human health and the environment from current and potential threats posed by
uncontrolled releases of hazardous substances. To help meet this mandate, the U.S. Environmental Protection
Agency's (EPA's) Office of Emergency and Remedial Response has developed a human health risk assessment
process as pan of its remedial response program. This process is described in Risk Assessment Guidance for
Superfund: Volume I — Human Health Evaluation Manual (RAGS/HHEM). Pan A of RAGS/HHEM
addresses the baseline risk assessment, and describes a general approach for estimating exposure to individuals
from hazardous substance releases at Superfund sites.
This bulletin explains the concentration term in the exposure/intake equation to remedial project
managers (RPMs), risk assessors, statisticians, and other personnel. This bulletin presents the general intake
equation as presented in RAGS/HHEM Pan A, discusses basic concepts concerning the concentration term,
describes generally how to calculate the concentration term, presents examples to illustrate several important
points, and, lastly, identifies where to get additional help.
THE CONCENTRATION TERM
How is the concentration term used?
RAGS/HHEM Pan A presents the
Superfund risk assessment process in four "steps*:
(1) data collection and evaluation; (2) exposure
assessment; (3) toxicity assessment; and (4) risk
characterization. The concentration term is
calculated for use in the exposure assessment step.
Highlight 1 presents the general equation
Superfund uses for calculating exposure, and
illustrates that the concentration term (Q is one
of several parameters needed to estimate
contaminant intake for an individual.
For Superfund assessments, the
concentration term (Q in the intake equation is
an estimate of the arithmetic average concentration
for a contaminant based on a set of site sampling
results. Because of the uncertainty associated with
estimating the true average concentration at a site.
the 95 percent upper confidence limit fUCL) of
the arithmetic mean should be used for this
variable. The 95 percent UCL provides reasonable
confidence that the true site average will not be
underestimated.
Why use an avenge value for the concentration
term?
An estimate of average concentration is used
because:
Supplemental Guidance to RAGS a a bulletin series on risk assessment of Superfund sites. These bulletins serve as supplements to
Risk Aaesonoa Guidance for SuperftaitL Volume I— Human Health Evaluation Manual. The information presented is intended as
guidance to EPA and other government employees. It does not constitute rulemaking by the Agency, and may not be relied on to
create a substantive or procedural right enforceable by any other person. The Government may taJce action that is at variance with
these bulletins.
-------
Highlight 1
GENERAL EQUATION FOR ESTIMATING EXPOSURE
TO A SITE CONTAMINANT
AT
BW
where:
I = intake (Le., the quantitative measure of exposure in RAGS/HHEM)
C = contaminant concentration
CR = contact (intake) rate
EFD = exposure frequency and duration
BW = body weight
AT == averaging time
(1)
(2)
carcinogenic and chronic noncarrinogenic
toxicity criteria1 are based on lifetime
average exposures; and
average concentration is most
representative of the concentration that
would be contacted at a site over time.
For example, if you assume that an exposed
individual moves randomly across an exposure
area, then the spatially averaged soil concentration
can be used to estimate the true average
concentration contacted over time. In this
example, the average concentration contacted over
time would equal the spatially averaged
concentration over the exposure area. While an
individual may not actually exhibit a truly random
pattern of movement across an exposure area, the
assumption of equal time spent in different parts
of the area is a simple but reasonable approach,
When should an average concentration be used?
The two types of exposure estimates now
being required for Superfund risk assessments, a
reasonable TnairiTrmtn exposure (RME) and an
average, should both use an average concentration.
To be protective, the overall estimate of intake
(see TTighiight i) used as a basis for action at
1 When acute toxicity is of most concern, a long-
term average concentration generally should not be
used for risk assessment purposes, as the focus
should be to estimate short-term, peak
concentrations.
Superfund sites should be an estimate in the high
end of the intake/dose distribution. One high-end
option is the RME used in the Superfund
program. The RME, which is defined as the
highest exposure that could reasonably be expected
to occur for a given exposure pathway at a site, is
intended to account for both uncertainty in the
contaminant concentration and variability in
exposure parameters (e.g., exposure frequency,
averaging time). For comparative purposes,
Agency guidance (U.S. EPA, Guidance on Risk
Characterization for Risk Managers and Risk
Assessors, February 26,1992) states that an average
estimate of exposure also should be presented in
risk assessments. For decision-making purposes in
the Superfund program, however, RME is used to
estimate risk.2
Why use an estimate of the arithmetic mean
rather than the geometric mean?
The choice of the arithmetic mean
concentration as the appropriate measure for
estimating exposure derives from the need to
estimate an individual's long-term average
exposure. Most Agency health criteria are based
on the long-term average daily dose, which is
simply the sum of all daily doses divided by the
total number of days in the averaging period. This
is the definition of an arithmetic mean. The
2 For additional information on RME, see
RAGS/HHEM Part A and the National Oil and
Hazardous Substances Pollution Contingency Plan
(NCP), 55 Federal Register 8710, March 8,1990.
-------
arithmetic mean is appropriate regardless of the
pattern of daily exposures over time or the type of
statistical distribution that might best describe the
sampling data. The geometric mea of a set of
sampling results, however, bears no logical
connection to the cumulative intake that would
result from long-term contact with site
contaminants, and it may differ appreciably from —
and be much lower than — the arithmetic mean.
Although the geometric mean is a convenient
parameter for describing central tendencies of
lognonnal distributions, it is not an appropriate
basis for estimating the concentration term used in
Superfund exposure assessments. The following
simple example may help clarify the difference
between the arithmetic and geometric mean when
used for an exposure assessment:
Assume the daily exposure for a trespasser
subject to random exposure at a site is 1.0,
0.01, 1.0, 0.01, 1.0, 0.01, 1.0, and 0.01
units/day over an 8-day period. Given
these values, the cumulative exposure is
simply their summation, or 4.04 units.
Dividing this by 8 days of exposure results
in an arithmetic mean of 0.505 units/day.
This is the value we would want to use in
a risk assessment for this individual, not
the geometric mean of 0.1 units/day.
Viewed another way, multiplication of the
geometric mean by the number of days
equals 0.8 units, considerably lower than
the known cumulative exposure of 4.04
units.
UCL AS AN ESTIMATE OF THE
AVERAGE CONCENTRATION
What is a 95 percent UCL?
The 95 percent UCL of a mean is defined
as a value that, when calculated repeatedly for
randomly drawn subsets of site data, equals or
exceeds the true mean 95 percent of the time.
Although the 95 percent UCL of the mean
provides a conservative estimate of the average (or
mean) concentration, it should not be confused
with a 95th percentile of site concentration data (as
shown in Highlight 2).
Why use the UCL as the average concentration?
Statistical confidence limits are the classical
tool for addressing uncertainties of a distribution
average. The 95 percent UCL of the arithmetic
mean concentration is used as the average
concentration because it is not possible to know
the true mean. The 95 percent UCL therefore
accounts for uncertainties due to limited sampling
data at Superfund sites. As sampling data become
less limited at a site, uncertainties decrease, the
UCL moves closer to the true mean, and exposure
evaluations using either the mean or the UCL
produce similar results. This concept is illustrated
in Highlight 2.
Should a value other than the 95 percent UCL be
used for the concentration?
A value other than the 95 percent UCL
can be used provided the risk assessor can
document that high coverage of the true
population mean occurs (Le., the value equals or
exceeds the true population mean with high
probability). For exposure areas with limited
amounts of data or extreme variability in measured
or modeled data, the UCL can be greater than the
highest measured or modeled concentration. In
these cases, if additional data cannot practicably be
obtained, the highest measured or modeled value
could be used as the concentration term. Note,
however, that the true mean still may be higher
than this maximum value (i.e., the 95 percent UCL
indicates a higher mean is possible), especially if
the most contaminated portion of the site has not
been sampled.
CALCULATING THE UCL
How many samples are necessary to calculate the
95 percent UCL?
Sampling data from Superfund sites have
shown that data sets with fewer than 10 samples
per exposure area provide poor estimates of the
mean concentration (Le., there is a large difference
between the sample mean and the 95 percent
UCL), while data sets with 10 to 20 samples per
exposure area provide somewhat better estimates
of the mean, and data sets with 20 to 30 samples
provide fairly consistent estimates of the mean
(Le., the 95 percent UCL is close to the sample
mean). Remember that, in general, the UCL
approaches the true mean as more samples are
included in the calculation.
Should the data be transformed?
EPA's experience shows that most large or
"complete" environmental contaminant data sets
-------
Highlight 2
COMPARISON OF UCL AND 95* PERCENTELE
Concentration
As sample size increases, the UCL of the mean moves closer to the true mean, while the 95th
percentile of the distribution remains at the upper end of the distribution.
i
from sofl sampling are lognormalty distributed
rather than normally distributed (see Highlights 3
and 4 for illustrations of lognormal and normal
distributions). In most cases, it is reasonable
to assume that Superfnnd sofl sampling data are
lognormaUy distributed. Because transformation is
a necessary step in calculating the UCL of the
arithmetic mean for a lognormal distribution, the
data should be transformed by using the natural
logarithm function (Le^ calculate ln(x), where x is
the value from the data set). However, in cases
where there is a question about the distribution of
the data set, a statistical test should be used to
identify the best distributional assumption for the
data set The W-test (Gilbert 1987) is one
statistical method that can be used to determine if
a data set is consistent with a normal or lognormal
distribution. In all cases, it is valuable to plot the
data to better understand the contaminant
distribution at the site.
How do you calculate the UCL for a lognormal
distribution?
To calculate the 95 percent UCL of the
arithmetic mean for a lognonnalry distributed data
set, first transform the data using the natural
logarithm function as discussed previously (Le^
calculate ln(x)). After transforming the data,
determine the 95 percent UCL tor the data set by
completing the following four steps:
(1)
(2)
(3)
(4)
How do you f»l"fl»*»' the UCL for a normal
distribution?
If a statistical test supports the assumption
that the data set is normally distributed, calculate
the 95 percent UCL by completing the following
four steps:
Calculate the arithmetic mean of the
transformed data (which is also the log of
the geometric mean);
Calculate the standard deviation of the
transformed data;
Determine the H-statistic (e,g, see Gilbert
1987); and
Calculate the UCL using the equation
shown in TTtghitght 5.
-------
so -
Highlight 3
EXAMPLE OF A LOGNORMAL DISTRIBUTION
so
35
40
Concentration
Highlight 4
EXAMPLE OF A NORMAL DISTRIBUTION
30
Concentration
-------
where:
UCL «
e =
x =
s =
H
n =
Highlights
CALCULATING TEE UCL OF THE ARITHMETIC MEAN
FOR A LOGNORMAL DISTRIBUTION
UCL = e *
upper confidence limit
constant (base of the natural log, equal to 2.718)
mean of the transformed data
standard deviation of the transformed data
H-statistic (e.g., from table published in Gilbert 1987)
number of samples
Highlight 6
CALCULATING THE UCL OF THE ARITHMETIC MEAN FOR A NORMAL DISTRIBUTION
where:
UCL =
s =
t =
n =
upper confidence limit
mean of the untransformed data
standard deviation of the untransformed data
Student-t statistic (e.g., from table published in Gilbert 1987)
number of samples
(1) Calculate the arithmetic mean of the
untransformed data;
(2) Calculate the s'tandard deviation of the
untransformed data;
(3) Determine the one-tailed t-statistic (e.g.,
see Gilbert 1987); and
(4) Calculate the UCL using the equation
presented in Highlight 6.
Use caution when applying normal distribution
calculations if there is a possibility that heavily
contaminated portions of the site have not been
adequately sampled. In such cases, a UCL from
normal distribution calculations could fall below
the true mean, even if a limited data set at a site
appears normally distributed.
EXAMPLES
The examples shown in Highlights 7 and 8
address the exposure scenario where an individual
at a Superfund site has equal opportunity to
contact soil in any sector of the contaminated area
over time. Even though the examples address only
soil exposures, the UCL approach is applicable to
all exposure pathways. Guidance and examples for
other exposure pathways win be presented in
forthcoming bulletins.
Highlight 7 presents a simple data set and
provides a stepwise demonstration of transforming
the data — assuming a log-normal distribution —
and calculating the UCL. Highlight 8 uses the
same data set to show the difference between the
UCLs that would result from assuming normal and
lognormal distribution of the data. These
-------
Highlight 7
EXAMPLE OF DATA TRANSFORMATION AND CALCULATION OF UCL
This example shows the calculation of a 95 percent UCL of the arithmetic mean
concentration for chromium in soil at a Superfund site. This example is applicable only to a
scenario in which a spatially random exposure pattern is assumed. The concentrations of chromium.
obtained from random sampling in soil at this site (in mg/kg) are 10, 13, 20, 36, 41, 59, 67, 110, 110,
136, 140, 160, 200, 230, and 1300. Using these data, the following steps are taken to calculate a
concentration term for the intake equation:
(1) Plot the data and inspect the graph. (You may need the help of a statistician for this part
[as well as other parts] of the calculation of the UCL.) The plot (not shown, but similar to
Highlight 3) shows a skew to the right, consistent with a lognormal distribution.
(2) Transform the data by taking the natural log of the values (Le., determine ln(x)). For this
data set, the transformed values are: 230, 236, 3.00, 338, 3.71, 4.08, 4.20, 4.70, 4.70, 4.91,
4.94, 5.08, 530, 5.44, and 7.17.
(3) Apply the UCL equation in Highlight 5, where:
x = 438
H - 3.163 (based on 95 percent)
n = 15 t
The resulting 95 percent UCL of the arithmetic mean is thus found to equal e^6-218), or 502 mg/kg.
Highlights
COMPARING UCLS OF THE ARITHMETIC MEAN ASSUMING DIFFERENT DISTRIBUTIONS
In this example, the data presented in Highlight 7 are used to demonstrate the difference in
the UCL that is seen if the normal distribution approach were inappropriately applied to this data
set (Le., if, in this example, a normal distribution is assumed).
ASSUMED DISTRIBUTION: Normal Lognormal
TEST STATISTIC: Student-t H-statistic
95 PERCENT UCL (mg/kg): 325 502
-------
examples demonstrate the importance of using the
correct assumptions.
WHERE CAN I GET MORE HELP?
Additional information on Superfund's
policy and approach to calculating the
concentration term and estimating exposures at
waste sites can be obtained in:
• U.S. EPA, Risk Assessment Guidance
far Superfund: Volume I — Human
Health Evaluation Manual (Part A),
EPA/540A-89/002, December 1989.
• ' U.S. EPA, Guidance for Data
Useability in Risk Assessment,
EPA/540/G-90/008 (OSWER
Directive 9285,7-05), October 1990.
>
• U.S. EPA, Risk Assessment Guidance
for Superfund (Part A —Baseline Risk
Assessment) Supplemental Guidance/
Standard Exposure Factors, OSWER
Directive 9285.6-03, May 1991.
Useful statistical guidance can be found in many
standard textbooks, including:
• Gilbert, R.O., Statistical Methods for
Environmental Pollution Monitoring,
Van Nostrand Reinhold, New York,
New York, 1987.
Questions or comments concerning the
concentration term can be directed to:
• Toxics Integration Branch
Office of Emergency and Remedial
Response
401 M Street SW
Washington, DC 20460
Phone: 202-260-9486
EPA staff can obtain additional copies of this
bulletin by calling EPA's Superfund Document
Center at 202-260-9760. Others can obtain copies
by contacting NTTS at 703-487-4650.
United States
Environmental Protection
Agency (OS-230)
Washington, DC 20460
Official Business
Penalty for Private Use
$300
Rrst-Class Mall
Postage and Fees Paid
EPA
Permit No. G-35
-------
QUANTIFYING EXPOSURE
The following equations can be used to replace the equations found in the Human Health Evaluation
Manual: Part A (HHEM). These equations reflect the current guidance for quantifying particular
exposure pathways.
AGE-ADJUSTED SOIL INGESTION
The following equation illustrates how to address the different intake rates and body weights of an
adult and a child for soil ingestion. This equation is an expansion of the equation found on page
6-40 of the HHEM: Part A.
Intake (mg/kg/day) =
CS x IRc x CF x FIc x EFc x EDc
BWc x AT
CS x IRa x CF x Fla x EFa x EDa
BWa x AT
The c denotes factors that should be based on a child's activities and the a denotes adult values.
The averaging time would be the same for both (e.g., 30 years) if calculating for intake of a
carcinogenic chemical or a time period that covers a child and an adult. If the time period of activity
is only for a child or an adult, then only part of the above equation would be used.
INHALATION OF VOLATILES RESIDENTIAL WATER
The inhalation route of exposure due to residential use of water has become as important as the
ingestion route. The Residential Exposure: Inhalation of Airborne Chemicals (HHEM: Part A,
page 6-44) shows how to calculate an intake if the airborne concentration is known. There are two
sources for this concentration: 1) air sampling or 2) modeling. The following two equations show
how to model airborne concentrations for volatile compounds released during showering (Shower
Scenario) or during the complete daily usage of water (Whole House Scenario). Note: Do not try
to add the two equations. The Whole House Scenario includes the release of volatiles during
showering.
8/93 1 Quantifying Exposure
-------
SHOWER SCENARIO
~A _ CW x Liters shower x Volatility
Room Volume
where:
CA = contaminant concentration in air in bathroom (mg/m3)
CW = contaminant concentration in water (mg/L)
Liters shower = volume of water used during shower
Volatility = percent of contaminant that volatilizes (e.g., 50 percent = 0.5)
Room volume = volume of bathroom (or shower) in m3.
WHOLE HOUSE SCENARIO
The following equation was taken from Human Health Evaluation Manual, Part B: Development
of Risk-based Preliminary Remediation Goals (page 52, B.I. 2), with a slight modification to fit the
format of Part A. It addresses volatilization of contaminants1 from all of the residential water used
in a house, not just during showering.
Cw x K x IR x EF x ED
Intake (mg/kg-day) = x AT
where:
Cw = contaminant concentration in water (mg/L)
K = volatilization factor (0.0005 x 1000 L/m3.2 The number
shown here is the default value used in HHEM: Part B.
It is based on certain water use factors, house size, and
ventilation rate. It also represents the upper-bound number
for a variety of chemicals. A chemical-specific number
may be more realistic.
IR = daily indoor inhalation rate (mVday)
EF = exposure frequency (days/yr)
1 Andelman 1990.
2 Andelman 1990.
Quantifying Exposure 2 8/93
-------
ED = exposure duration (yr)
BW = body weight (kg)
AT = averaging time (days).
At scoping, risk from indoor inhalation of volatiles is assumed to be relevant only for
chemicals that easily volatilize. Thus, the risk equation incorporates a water-air
concentration relationship that is applicable only to chemicals with a Henry's Law
constant of greater than 1 x 10"5 atm-nrVmole and a molecular weight of less than 200
g/mole. (HHEM: Part B, page 20 [emphasis added])
DERMAL CONTACT WITH CHEMICALS
The following equations were taken from the Dermal Exposure Assessment: Principles and
Applications (Interim Report), Office of Research and Development, EPA/600/8-91/01 IB. These
replace the equations found on pages 6-37 and 6-41 of the Human Health Evaluation Manual: Part
Aj. Please refer to the dermal exposure assessment document for complete procedures.
DERMAL CONTACT WITH CHEMICALS IN WATER
DA EV ED EF A
DAD =
'event
BWAT
where:
DAD = dermally absorbed dose (mg/kg-day)
DAevcot = absorbed dose per event (mg/cm2-event)
EV = event frequency (events/day)
ED = exposure duration (years)
EF = exposure frequency (days/year)
A = skin surface area available for contact (cm2)
BW = body weight (kg)
AT = averaging time (days) - for noncarcinogenic effects, AT = ED; for
carcinogenic effects, AT = 70 years or 25,550 days.
Recommended default values for dermal exposure for EV, ED, EF, and A are provided in Table 1.
8/93 3 Quantifying Exposure
-------
TABLE 1. RANGE OF RECOMMENDED DEFAULTS
FOR DERMAL EXPOSURE FACTORS
Water Contact
Bathing
Exposure
Factor
Event time
and
frequency
Exposure
duration
Adult skin
surface area*
Soil-to-skin
adherence
rate
Central
10 minutes per
event, 1 event
per day, 350
days per year
9 years
20,000 cm2
..«
Upper
1 5 minutes per
event, 1 event
per day, 350
days per year
30 years
23,000 cm2
..
Swimming
Central
0.5 hours per
event, 1 event
per day, 5 days
per year
9 years
20,000 cm2
..
Upper
1 hour per
event, 1 event
per day, 1 50
days per year
30 years
23,000 cm2
—
Soil Contact
Central Upper
40 events 350 events
per year per year
9 years 30 years
5,000 cm* 5,800 cm2
0.2 mg/cm2- 1 .0 mg/cm2-
event event
Source: Table 8-6, Dermal Exposure Assessment: Principles and Applications. Interim Report.
EPA/600/8-91/01 IB. U.S. Environmental Protection Agency, Office and Research and Development.
* See Table 8-4, Dermal Exposure Assessment: Principles and Applications for values for children.
b This value represents the area of body exposed while wearing summer-type clothing. It equals 25 percent
of total body surface.
c - indicates not applicable.
Quantifying Exposure
8/93
-------
For inorganics, DAevent (mg/cm2-event) can be calculated as follows:
where:
= dose absorbed per unit area per event (mg/cm2-event)
K* = permeability coefficient from water (cm/hour)
Cw = concentration of chemical in water (mg/cm3)
(Note: mg/cm3 = lO'6 x ng/L)
tevwt = duration of event (hr/event).
Values for K* can be found in Chapter 5 of Dermal Exposure Assessment: Principles and
Applications.
For organics, DA,.^ (mg/cm2-event) can be calculated as follows:
event . ~
1 + B
1 + 3 B\
1 + B J.
Cv = contaminant concentration in water (mg/cm3). Values for Kp, t*, T, and B can be found in
Chapter 5 of Dermal Exposure Assessment: Principles and Applications.
8/93 5 Quantifying Exposure
-------
DERMAL CONTACT WITH CHEMICALS IN SOIL
DA EF ED A
DAD =
event
BWAT
where:
DAD = dermally absorbed dose (mg/kg-day)
absorbed dose per event (mg/cm2-event)
EF = exposure frequency (events/year)
ED = exposure duration (years)
A = skin surface area available for contact (cm2)
BW = body weight (kg)
AT = averaging time (days) - for noncarcinogenic effects, AT = ED; for
carcinogenic effects, AT = 70 years or 25,550 days.
cm2-event) for soil can be calculated as follows:
ABS
where:
Qoii = contaminant concentration in soil (mg/kg)(10"6 kg/mg)
AF = adherence factor of soil to skin (mg/cm2-event) (also referred to as contact
rate in RAGS Part A)
ABS = absorption fraction (e.g., 10 percent = 0.1).
Quantifying Exposure 6 8/93
-------
TOXICITY VALUES INFORMATION SOURCES & HIERARCHY
(HHEM Pages 7-13 to 7-15)
INTEGRATED RISK INFORMATION SYSTEM (IRIS)
• To set up an on-line IRIS account (updated monthly):
(301) 496-6531 "Toxnet" through National Library of Medicine.
• To obtain IRIS on computer disk (updated quarterly):
U.S. Environmental Protection Agency (EPA) personnel and state and federal
agencies call for personal computer version. Contact National Technical
Information Service (NTIS) at 703 487-4807 or 1-800-336-4700.
• To access or order the IRIS database:
IRIS User Support 513 569-7254.
• To obtain technical or scientific guidance for IRIS workgroup verification data:
EPA regional Superfund personnel consult EPA agency contact identified at
the end of each IRIS file.
HEALTH EFFECTS ASSESSMENT SUMMARY TABLES (HEAST)
• To order HEAST:
Contact NTIS at 1-800-553-6847 to obtain whole document (43.00)
Contact NTIS at 703 487-4630 to subscribe to HEAST for periodic updates.
• To order documents referenced in HEAST:
Center for Environmental Research Information (CERI) - 513 569-7562
NTIS - 703 487-4650 or 1-800-553-NTIS.
EPA ENVIRONMENTAL CRITERIA AND ASSESSMENT OFFICE (ECAO)
SUPERFUND HEALTH RISK TECHNICAL SUPPORT CENTER (TSC)
• For technical assistance for EPA personnel:
Contact ECAO at 513 569-7300.
8/93 i Toxicity Information
-------
Contractors/others—Questions must be submitted to the TSC in writing and must
contain the following information:
Superfund site name, site location, and 12-digit site number
Name and telephone number of the RPM or regional risk assessor/toxicologist
Detailed description of the risk assessment-related question.
Sources for EPA documents
CERI—No charge for documents
Center for Environmental Research Information
ORD Publications
26 West Martin Luther King Drive
Cincinnati, OH 45268
513 569-7562
NTIS—Cost varies
National Technical Information Service
, 5285 Port Royal Road
Springfield, VA 22161
703 487-4650
1-800-553-NTIS
Superfund Docket and Information Center (SDIC)—No charge for documents
U.S. Environmental Protection Agency
Superfund Docket and Information Center
OS-245
401 M Street SW
Washington, DC 20460
202 260-6940
FTS 8-382-6940
RCRA/Superfund Hotline
1-800-424-9346
RCRA Documents
202 475-9327.
FATE AND TRANSPORT INFORMATION SOURCES
The following sources can provide information related to chemical fate and transport. This list is
not exhaustive. There are many models and publications concerning fate and transport that are not
mentioned here.
The first two sources are U.S. EPA Technical Support Centers. They are prepared to provide
technical assistance to RPMs and OSCs. Other persons should go through their site RPM or OSC
or regional risk assessor if technical assistance is needed. Anyone interested in publications and
models can contact the centers directly.
Toxicity Information 2 8/93
-------
1. Ground-Water Fate and Transport Technical Support Center
Robert S. Kerr Environmental Research Laboratory (RSKERL)
Kerr Lab Road
P.O. Box 1198
Ada, OK 74820
405 332-8800
RSKERL is EPA's center for fate and transport research, focusing on 1) transport and fate
of contaminants in the vadose and saturated zones of the subsurface, 2) methodologies
relevant to protection and restoration of groundwater quality, and 3) evaluation of subsurface
processes for the treatment of hazardous waste. The laboratory's Center for Subsurface Fate
and Transport provides technical support pertaining to:
• Pump-and-treat aquifer remediation
• Bioremediation of soils and groundwater
• Subsurface geochemistry
• Contaminant transport modeling
• In situ treatment processes.
2. Exposure and Ecorisk Assessment Technical Support Center
Environmental Research Laboratory (ERL-Athens)
College Station Road
Athens, GA 30613
706 546-3130
706 546-3402 (bulletin board)
706 546-3549 (list of models)
ERL-Athens emphasizes multimedia exposure and risk assessment modeling of remedial
action alternatives. An electronic bulletin board disseminates models and modeling
information. Technical support services include:
• Models, databases, and analytical techniques
• Multimedia modeling of organic chemical and heavy metal pollutant fate
• Soil/water and surface water/sediment systems
• Ecological impact and ecorisk assessment.
Models can be downloaded from the bulletin board or a disk of the model can be obtained.
A disk listing the models is available by calling 706 546-3549.
8/93 3 Toxicity Information
-------
AQUIRE Database
U.S. Environmental Protection Agency
Office of Research and Development
Office of Technology Transfer and Regulatory Support
202 260-7667
National Ground Water Association
Dublin, OH
614761-1711
RISKPRO®
General Sciences Corporation
6100 Chevy Chase Drive
Laurel, MD 20707
301 953-2700
RISKPRO® is a software package that combines chemical property estimation, environmental
models, risk estimation procedures, and graphic presentations. The risk estimation
procedures are in accordance with the guidelines set forth in the Risk Assessment Guidance
for Superfund documents. The models evaluate releases to air, soil, surface water, and
groundwater.
AGENCY FOR TOXIC SUBSTANCES AND DISEASE REGISTRY (ATSDR)
ATSDR Regional Representatives
i
Region
1
2
3
4
5
Contact
Louise A. House
617 860-4314
Arthur Block
212 264-7662
Charles J. Walters
215 597-7291
Chuck V. Pietrosewicz
404 639-0707
Louise A. Fabinski
312 886-0327
Region
6
7
8
9
10
Contact
Carl R. Hickam
214 655-2245
Denise Jordan-lzaguirre
913 551-7692
Glenn J. Tucker
303294-1063
William 0. Nelson
415 744-2194
Greg Thomas
206 553-2113
Toxicity Information
8/93
-------
INTEGRATED RISK INFORMATION SYSTEM
Substance Name:
CASRN:
Chlordane
57-74-9
Last Revised:
07/01/93
Health risk assessment information on a chemical is included in IRIS only after
a comprehensive review of chronic toxicity data by work groups composed of U.S.
EPA scientists from several Program Offices. The summaries presented in the
Oral RfD, Inhalation RfC and Carcinogenicity Assessment Sections represent a
consensus reached in the review process. The other sections 'contain U.S. EPA
information which is specific to a particular EPA program and has been subject
to review procedures prescribed by that Program Office. The Regulatory Actions
Section may not be based on the most current risk assessment, or may be based
on a current, but unreviewed, risk assessment, and may take into account
factors other than health effects (e.g., treatment technology). When
considering the use of regulatory action data for a particular situation, note
the date of the regulatory action, the date of the most recent risk assessment
relating to that action, and whether technological factors were considered.
Background information and explanations of the methods used to derive the
values given in IRIS are provided in the five Background Documents, which are
available in each section of the chemical files.
Category (section)
Status
Oral RfD Assessment
Inhalation RfC Assessment
Carcinogenicity Assessment
Drinking Water Health Advisories
U.S. EPA Regulatory Actions
Supplementary Data
Available
Under Rev
Available
Available
Available
Available
Last Revised
07/01/89
07/01/93
08/01/90
01/01/92
03/31/87
-------
Chlordane
RfD-1
Substance Name:
CASRN:
REFERENCE DOSE FOR CHRONIC ORAL EXPOSURE (RfD)
Chlordane
57-74-9
The Reference Dose (RfD) is based on the assumption that thresholds exist for
certain toxic effects such as cellular necrosis, but nay not exist for other
toxic effects such as carcinogenicity. In general, the RfD is an estimate
(with uncertainty spanning perhaps an order of magnitude) of a daily exposure
to the human population (including sensitive subgroups) that is likely to be
without an appreciable risk of deleterious effects during a lifetime. Please
refer to the Oral RfD Background Document for an elaboration of these concepts.
RfDs can also be derived for the noncarcinogenic health effects of compounds
which are also carcinogens. Therefore, it is essential to refer to other
sources of information concerning the carcinogenicity of this substance. If the
U.S. EPA has evaluated this substance for potential human carcinogenicity, a
summary of that evaluation will be contained in the Carcinogenicity Assessment
Section of this file when a review of that evaluation is completed.
RfD ASSESSMENT SUMMARY TABLE
Crit. Dose:
UF: 1000 MF:
0.055 mg/kg-day [Study 1 NOAEL(adj)]
1 RfD: 6E-5 mg/kg-day Confidence: Low
Crit Effect: (1) Regional liver hypertrophy in females
•NOAEL (Study l)-i—LOAEL -
Reported
ADJ
Study Type
Reference
1 ppm
0.055 mg/kg-day
30-Month Rat Feeding Study
Velsicol Chemical Co., 1983a
-(Study i)-,
5 ppm
0.273 mg/kg-day
30-Month Rat Feeding Study
Velsicol Chemical Co., 1983a
1) Velsicol Chemical Co., I983a
30-Month Rat Feeding Study
Critical Effect:
Regional liver hypertrophy in females
Defined Dose Levels:
NOAEL= 1 ppm
NOAEL (ADJ) «= 0.055 mg/kg-day
LOAEL= 5 ppm
LOAEL (ADJ) «= 0.273 mg/kg-day
Conversion Factors: Actual dose tested
DISCUSSION OF PRINCIPAL AND SUPPORTING STUDIES
Velsicol Chemical Company. I983a. MRID No. 00138591, 00144313. Available from
EPA. Write to FOI, EPA, Washington, DC 20460.
Charles River Fischer 344 rats (80/sex/dose) were fed technical Chlordane at
dietary levels of 0, 1, 5, and 25 ppm for 130 weeks. Body weight, food
-------
Chlordane RfD-2
———i——' REFERENCE DOSE FOR CHRONIC ORAL EXPOSURE (RfD) —————
consumption, and water uptake were monitored at regular intervals. Clinical
laboratory studies were performed and organ weights measured on eight
animals/sex/group at weeks 26 and 52, and on all survivors at week 130. Gross
and microscopic pathology were performed on all tissues. Daily dose level of
0.045, 0.229, and 1.175 mg/kg/day for males and 0.055, 0.273, and 1.409
mg/kg/day for females for the 1, 5, and 25 ppm treatment groups, respectively,
were calculated from food consumption and body weight data.
Following the submission of a 30-month chronic feeding/oncogenicity study in
Fischer 344 rats, the Agency reviews by the Office of Pesticides Programs and
the Cancer Assessment Group of these data indicated that male rats at the
highest dosage exhibited an increase in liver tumors (1CF Clement, 1987) . The
registrant, Velsicol Chemical Company, subsequently convened the Pathology
Working Group to reevaluate the slides of livers of the chlordane-treated rats
reported in MRID No. 00138591. It was concluded that liver lesions had not
occurred in male rats and that 25 ppm (0.1175 mg/kg/day) was the NOEL for
males. Liver lesions (hypertrophy), however, had occurred in female rats at 5
ppm (0.273 mg/kg/day), which was considered an LEL. Therefore an NOEL of 1 ppm
(0.055 mg/kg/day) (LDT) was established for female rats.
UNCERTAINTY FACTORS:
UNCERTAINTY AND MODIFYING FACTORS
An uncertainty factor of 100 was used to account for the inter- and
intraspecies differences. An additional UF of 10 was used to account for the
lack of an adequate reproduction study and adequate chronic study in a second
mammalian species, and the generally inadequate sensitive endpoints studied in
existing studies, particularly since chlordane is known to bioaccumulate over a
chronic duration.
ADDITIONAL COMMENTS / STUDIES
oata Considered for Establishing the RfD
1) 30-Month Feeding (oncogenic) - rat: Principal study - see previous
description; core grade minimum
2) 24-Month Chronic Toxicity - mouse: NOEL=1 ppm (0.15 mg/kg/day); LEL=5 ppm
(0.75 mg/kg/day) (hepatocellular swelling and necrosis in males; hepatocyte
swelling in males, and increased live weight in males and females); At 12.5 ppm
(1.875 mg/kg/day) (HDT); core grade minimum (Velsicol Chemical Co., 1983b)
Data Gap(s): Chronic Dog Feeding Study, Rat Reproduction Study, Rat Teratology
Study, Rabbit Teratology Study
CONFIDENCE IN THE RfD
Study: Medium Data Base: Low RfD: Low
The critical study is of adequate quality and is given a medium rating. The
data base is given a low confidence rating because of l) the lack of an
adequate reproduction study and adequate chronic study in a second mammalian
species and 2) inadequate sensitive endpoints studied in existing studies,
particularly since chlordane is known to bioaccumulate over a chronic duration.
-------
Chlordane RfD-3
—————= REFERENCE DOSE FOR CHRONIC ORAL EXPOSURE (RfD) —————
Low confidence in the RfD follows.
EPA DOCUMENTATION AND REVIEW
Source Document: This assessment is not presented in any existing U.S. EPA
document.
Other EPA Documention: Pesticide Registration Standard, November 1986;
Pesticide Registration Files
Agency Work Group Review: 12/18/85, 03/22/89
Verification Date: 03/22/89
EPA CONTACTS
William Burnam / OPP — (703)305-4791
George Ghali / OPP — (703)305-7490
BIBLIOGRAPHY
ICF-Clement. 1987. MRID No. 40433701. Available from EPA. Write to FOI,
EPA, Washington DC 20460.
Velsicol Chemical Co. I983a. MRID No. 00138591, 00144313. Available from
EPA. Write to FOI, EPA, Washington DC 20460.
Velsicol Chemical Co. I983b. MRID No. 00144312. Available from EPA. Write
to FOI, EPA, Washington DC 20460.
REVISION HISTORY
03/88 RfD Studies: Text clarified in paragraph 3
03/88 RfD Sum Tbl: Dose conversion clarified
04/89 RfD Data: Withdrawn; new RfD verified (in preparation)
06/89 RfD Data: Revised oral RfD summary added
07/89 RfD Studies: Reference clarified in paragraph 2
-------
Chlordane RfC-1
———= REFERENCE CONCENTRATION FOR CHRONIC INHALATION EXPOSURE (RfC)
Substance Name: Chlordane
CASRN: 57-74-9
Status: Under Rev
Note: A risk assessment for this substance/agent is under review by an EPA
work group.
Agency Work Group Review: 02/22/90
-------
Chlordane CARCIN-1
—————= CARCINOGENICITY ASSESSMENT FOR LIFETIME EXPOSURE —————
Substance Name: Chlordane
CASRN: 57-74-9
The Carcinogenicity Assessment Section provides information on three aspects of
the carcinogenic risk assessment for the agent in question; the U.S. EPA
classification, and quantitative estimates of risk from oral exposure and from
inhalation exposure. The classification reflects a weight-of-evidence judgment
of the likelihood that the agent is a human carcinogen. The quantitative risk
estimates are presented in three ways. The slope factor is the result of
application of a low-dose extrapolation procedure and is presented as the risk
per mg/kg/day. The unit risk is the quantitative estimate in terms of either
risk per ug/L drinking water or risk per ug/cu.ro air breathed. The third form
in which risk is presented is a drinking water or air concentration providing
cancer risks of 1 in 10,000, 1 in 100,000 or 1 in 1,000,000. The Carcinogen
Assessment Background Document provides details on the rationale and methods
used to derive the carcinogenicity values found in IRIS. Users are referred to
the Oral RfD and Inhalation RfC Sections for information on long-term toxic
effects other than carcinogenicity.
EVIDENCE FOR CLASSIFICATION AS TO HUMAN CARCINOGENICITY
WEIGHT-OF-EVIDENCE CLASSIFICATION
Classification: B2; probable human carcinogen
BASIS
Sufficient evidence in studies in which benign and malignant liver tumors were
induced in four strains of mice of both sexes and in F344 male rats;
structurally related to other liver carcinogens
HUMAN CARCINOGENICITY DATA
Inadequate. There were 11 case reports involving central nervous system
effects, blood dyscrasias and neuroblastomas in children with pre-/postnatal
exposure to chlordane and heptachlor (Infante et al., 1978). As no other
information was available, no conclusions can be drawn.
There were three epidemiologic studies of workers exposed to chlordane and/or
heptachlor. One study of pesticide applicators was considered inadequate in
sample size and duration of follow-up. This study showed marginal
statistically significant increased mortality from bladder cancer (3 observed)
(Hang and McMahon, 1979a). The other two studies were of pesticide
manufacturing workers. Neither of them showed any statistically significantly
increased cancer mortality (Wang and McMahon, 1979b; Ditraglia et al., 1981).
Both tBoth these populations also had confounding exposures from other chemicals
ANIMAL CARCINOGENICITY DATA
Sufficient. Chlordane has been studied in four mouse and four rat long-term
carcinogenesis bioassays. Dose-related incidences
-------
Chlordane CARCIN-2
——————= CARCINOGENICITY ASSESSMENT FOR LIFETIME EXPOSURE ———
constitute the major finding in mice. Becker and Sell (1979) tested chlordane
(90:10 mixture of chlordane to heptachlor) in C57B1/6N mice, a strain
historically known not to develop spontaneous liver tumors. An unspecified
number of mice were fed chlordane at 0, 25 and 50 ppm (0, 3.57, 7.14 mg/kg bw)
for 18 months. Hone of the controls developed tumors or nodular lesions of the
liver. Twenty-seven percent (16 mice) of the surviving treated mice developed
primary hepatocellular carcinomas. Velsicol (1973) fed groups of 100 male and
100 female CD-I mice diets with 0, 5, 25 or 50 ppm analytical grade chlordane
for 18 months. A significant (p<0.01) dose-related increase in nodular
hyperplasias in the liver of male and female mice was reported at the the two
highest dose levels. A histological review by Reuber (U.S. EPA, 1985) reported
a high incidence (p<0.0l) of hepatic carcinomas instead of hyperplastic nodules
at 25 and 50 ppm.
A dose-related increase (p<0.001 after lifetable adjustment) of hepatocellular
carcinomas was also observed in both sexes of B6C3F1 mice (NCI, 1977). Male
and female mice were fed technical-grade chlordane (purity\= 94.8%) at TWA
concentrations (TWAC) of 29.9 and 56.2 ppm and 30.1 and 63.8 ppm, respectively,
for 80 weeks. In this study there were individual matched controls for the low
and high dose groups. ICR male mice developed hepatocellular adenomas and
hemangiomas when fed 12.5 ppm chlordane for 24 months. No tumors were observed
in the female mice when tested at the same concentrations: 0, 1, 5, and 12.5
ppjn (Velsicol, 1983a) .
Velsicol (I983b) reported a long-term (130 weeks) carcinogenesis bioassay on 80
male and 80 female F344 rats fed concentrations of 0, 1, 5, and 25 ppm
chlordane. A significant increase in adenomas of the liver was observed in
male rats receiving 25 ppm. Although no tumors were observed in female rats,
hepatocellular swelling was significantly increased at 25 ppm. The NCI (1977)
reported a significant increase (p<0.05) of neoplastic nodules of the liver in
low-dose Osborne-Mendel female rats (TWAC of 120.8 ppm) but not in the
high-dose group (TWAC of 241.5 ppm). No tumor incidence was reported for the
males fed TWAC of 203.5 and 407 ppm. Loss of body weight and a dose-related
increase in mortality was observed in all treated groups. High mortality and
reduced growth rates in Osborne-Mendel rats was also observed by Ingle (1952)
when the rats were exposed to 150 and 300 ppm chlordane but not at 5, 10, and
30 ppm. No treatment-related incidence of tumors was reported. Significantly
enlarged livers and liver lesions were found in male and female albino rats fed
chlordane at greater than or equal to 80 ppm (Ambrose et al., 1953a,b). No
treatment-related increase in tumors was found, but the study duration (400
days) was short.
SUPPORTING DATA FOR CARCINOGENICITY
Gene mutation assays indicate that chlordane is not mutagenic in bacteria
(Wildeman and Nazar, 1982; Probst et al., 1981; Gentile et al., 1982).
Positive results have been reported in Chinese hamster lung V79 cells and mouse
lymphoma L5178Y cells with and without exogenous metabolism, as well as in
plant assays. Chlordane did not induce DNA repair in bacteria, rodent
hepatocytes (Maslansky and Williams, 1981), or human lymphoid cells (Sobti et
al. , 1983). It is a genotoxicant in yeast (Gentile et al., 1982; Chambers and
Dutta, 1976), human fibroblasts (Ahmed et al., 1977), and fish (Vigfusson et
al., 1983).
-------
Chlordane
CARCINOGENICITY ASSESSMENT FOR LIFETIME EXPOSURE
CARCIN-3
Five compounds structurally related to chlordane (aldrin, dieldrin, heptachlor,
heptachlor apoxide, and chlorendic acid) have produced liver tumors in mice.
Chlorendic acid has also produced liver tumors in rats.
QUANTITATIVE ESTIMATE OF CARCINOGENIC RISK FROM ORAL EXPOSURE
Slope Factor:
Unit Risk:
Extrapolation Method:
1.3E+0 per mg/(kg/day)
3.7E-5 per ug/liter
Linearized multistage procedure, extra risk
Drinking Water Concentrations at Specified Risk Levels:
Risk Level
E-4 (1 in 10,000)
E-5 (1 in 100,000)
E-6 (1 in 1,000,000)
Concentration
3E+0 ug/liter
3E-1 ug/liter
3E-2 ug/liter
Tumor Type:
Test Animals:
Route:
DOSE-RESPONSE DATA (CARCINOGENICITY, ORAL EXPOSURE)
hepatocellular carcinoma
mouse/CD-I (Velsicol); mouse/B6C3Fl
diet
(NCI)
Administered
Dose (ppm)
female
0
5
25
50
male
0
5
25
50
male
0
29.9
56.2
female
0
30.1
63.8
Human Equivalent
Dose (mg/kg-day)
0.000
0.052
0.260
0.520
0.000
0.052
0.260
0.520
0.00
0.31
0.58
0.00
0.31
0.66
Tumor
Incidence
0/45
0/61
32/50
26/37
3/33
5/55
41/52
32/39
male
2/18
16/48
43/49
0/19
3/47
34/49
Reference
Velsicol,
1973
Velsicol,
1973
NCI, 1977
NCI, 1977
ADDITIONAL COMMENTS (CARCINOGENICITY, ORAL EXPOSURE)
Four data sets for mice and one data set for rats showed a significant increase
in liver tumors; namely hepatocellular carcinomas in mice (NCI, 1977; Velsicol,
1973) and hepatocellular adenomas in rats (Velsicol, I983a). The quantitative
estimate is based on the geometric mean from the four mouse data sets as mice
were the more sensitive species tested and as risk estimates for a similar
compound (heptachlor) were similarly derived from mouse tumor data. The slope
factors for the data sets are these: 2.98 per (mg/kg)/day for CD-I female
-------
Chlordane CARCIN-4
——————— CARCINOGENICITY ASSESSMENT FOR LIFETIME EXPOSURE •—^^———
mice, 4.74 per (mg/kg)/day for CD-I male mice, 0.76 per (mg/kg)/day for B6C3F1
male nice, and 0.25 per (ng/kg)/day for B6C3F1 female mice. Low and high dose
groups in the NCI (1977) study had individual matched controls.
The unit risk should not be used if the water concentration exceeds 300 ug/L,
since above this concentration the unit risk may not be appropriate.
DISCUSSION OF CONFIDENCE (CARCINOGENICITY, ORAL EXPOSURE)
Liver carcinomas were induced in mice of both sexes in two studies. An
adequate number of animals was observed, and dose-response effects were
reported in all studies. The geometric mean of slope factors (0.25 to 4.74 per
(mg/kg)/day for the most sensitive species is consistent with that derived from
rat data (1.11/mg/kg/day).
— QUANTITATIVE ESTIMATE OF CARCINOGENIC RISK FROM INHALATION EXPOSURE —
Unit Risk: 3.7E-4 per (ug/cu.m)
Extrapolation Method: Linearized multistage procedure, extra risk
Air Concentrations at Specified Risk Levels:
Risk Level Concentration
E-4 (1 in 10,000) 3E-1 per (ug/cu.m)
E-5 (1 in 100,000) 3E-2 per (ug/cu.ro)
E-6 (1 in 1,000,000) 3E-3 per (ug/cu.m)
DOSE-RESPONSE DATA (CARCINOGENICITY, INHALATION EXPOSURE)
The inhalation risk estimates were calculated from the data given in the oral
exposure data table.
ADDITIONAL COMMENTS (CARCINOGENICITY, INHALATION EXPOSURE)
The unit risk should not be used if the air concentration exceeds 30 ug/cu.m,
above this concentration the unit risk may not be appropriate.
DISCUSSION OF CONFIDENCE (CARCINOGENICITY, INHALATION EXPOSURE)
See oral quantitative estimate
EPA DOCUMENTATION AND REVIEW
Source Document: U.S. EPA. 1986. Carcinogenicity Assessment of Chlordane and
Heptachlor/ Heptachlor Epoxide. Prepared by the Office of Health and
Environmental Assessment, carcinogen Assessment Group, Washington, DC.
U.S. EPA. 1985. Hearing Files on Chlordane, Heptachlor Suspension
(unpublished draft). Available for inspection at U.S. EPA, Washington, DC.
The values in the 1986 Carcinogenicity Assessment for Chlordane and
Heptachlor/Heptachlor Epoxide have been reviewed by the Carcinogen Assessment
Group.
-------
Chlordane CARCIN-5
———— CARCINOGENICITY ASSESSMENT FOR LIFETIME EXPOSURE —————
Agency Work Group Review: 04/01/87
Verification Date: 04/01/87
EPA CONTACTS (CARCINOGENICITY ASSESSMENT)
Dharm Singh / OHEA — (202)260-5958
Jim Cogliano / OHEA — (202)260-3814
BIBLIOGRAPHY
Ahmed, F.E., R.W. Hart and N.J. Lewis. 1977. Pesticide induced DNA damage and
its repair in cultured human cells. Mutat. Res. 42: 161-174.
Ambrose, A.M., H.E. Christensen, D.J. Robbins and L.J. Rather. 1953a.
Toxi-cological and pharmacological studies on chlordane. Arch. Ind. Hyg.
Occup. Med. 7: 197-210.
Ambrose, A.M., H.E. Christensen and D.J. Robbins. 1953b. Pharmacological
observations on chlordane. Fed. Proceed. 12: 298. (Abstract #982)
Becker, F.F. and S. Sell. 1979. Fetoprotein levels and hepatic alterations
during chemical carcinogenesis in C57BL/6N mice. Cancer Res. 39: 3491-3494.
Chambers, D. and S.K. Dutta. 1976. Mutagenic tests of chlordane on different
microbial tester strains. Genetics. 83: sl3. (Abstract)
Ditraglia, D., D.P. Brown, T. Namekata and N. Iverson. 1981. Mortality study
of workers employed at organochlorine pesticide manufacturing plants. Scand.
J. Work Environ. Health. 7(4): 140-146.
Gentile, J.M., G.J. Gentile, J. Bultman, R. Sechriest, E.D. Wagner and M.J.
Plewa. 1982. An evaluation of the genotoxic properties of insecticides
following plant and animal activation. Mutat. Res. 101: 19-29.
Infante, P.F., S.S. Epstein and K.A. Newton. 1978. Blooddyscrasis and
childhood tumors and exposure to chlordane and heptachlor. Scand. J. Work
Environ. Health. 4: 137-150.
Ingle, L. 1952. Chronic oral toxicity of chlordan to rats. Arch. Ind. Hyg.
Occup. Med. 6: 357-367.
Maslansky, C.J. and G.M. Williams. 1981. Evidence for an epigenetic mode of
action in organochlorine pesticide hepatocarcinogenicity: A lack of
genotoxicity in rat, mouse, and hamster hepatocytes. J. Toxicol. Environ.
Health. 8: 121-130.
NCI (National Cancer Institute). 1977. Bioassay of Chlordane for possible
Carcinogenicity. NCI Carcinogenesis Tech. Rep. Ser. No. 8. U.S. DHEW Publ.
No. (NIH) 77-808. Bethesda, MD. '
Probst, G.S., R.E. McMahon, L.E. Hill, C.Z. Thompson, J.K. Epp and S.B. Neal.
1981. Chemically-jinduced unscheduled DNA synthesis in primary rat hepatocyte
cultures: A comparison with bacterial mutagenicity using 218 compounds.
-------
Chlordane CARCIN-6
«•—•—•—— CARCINOGENICTTY ASSESSMENT FOR LIFETIME EXPOSURE _____
Environ. Mutagen. 3: 11-31.
Sobti, R.C., A. Krishan and J. Davies. 1983. Cytokinetic and cytogenetic
effect of agricultural chemicals on human lynphoid cells in vitro. Arch.
Toxicol. 52: 221-231.
U.S. EPA. 1985. Hearing Files on Chlordane, Heptachlor Suspension (unpub-
lished draft). Available for inspection at U.S. EPA, Washington, DC.
U.S. EPA. 1986. Carcinogenicity Assessment of Chlordane and Heptachlor/
Heptachlor Epoxide. Prepared by the Office of Health and Environmental
Assessment, Carcinogen Assessment Group, Washington, DC.
Velsicol Chemical Corporation. 1973. MRID No. 00067568. Available from EPA.
Write to FOI, EPA, Washington, DC. 20460.
Velsicol Chemical Corporation. 1983a. MRID No. 00144312, 00132566. Available
from EPA. Write to FOI, EPA, Washington, DC. 20460.
Velsicol Chemical Corporation. I983b. MRID No. 00138591. Available from EPA.
Write to FOI, EPA, Washington, DC. 20460.
Vigfusson, N.V., E.R. Vyse, C.A. Pernsteiner and R.J. Dawson. 1983. In vivo
induction of sister-chromatid exchange in Umbra limi by the insecticides
endrin, Chlordane, diazinon and guthion. Mutat. Res. 118: 61-68.
Wang, H.H. and B. MacMahon. 1979a. Mortality of workers employed in the
manufacture of Chlordane and heptachlor. J. Occup. Med. 21(11): 745-748.
Wang, H.H. and B. MacMahon. I979b. Mortality of pesticide applicators. J.
Occup. Med. 21(11): 741-744.
Wildeman, A.G. and R.N. Nazar. 1982. Significance of plant metabolism in the
mutagenicity and toxicity of pesticides. Can. J. Genet. Cytol. 24: 437-449.
REVISION HISTORY.
09/87 Ca Data: Carcinogenicity section added
03/88 Ca Classif: Basis for classification clarified
07/89 Ca Data: Velsicol (1983) references clarified
07/89 Ca Refs: Carcinogen references added
01/91 Ca Data: Text edited
01/91 Ca In Summ: Inhalation slope factor removed (global change)
07/93 Ca Contact: Secondary contact's phone number changed
-------
Chlordane DWHA-1
•••• DRINKING WATER HEALTH ADVISORIES ————————
Substance Name: Chlordane
CASRN: 57-74-9
The Office of Water provides Drinking Water Health Advisories (HAs) as
technical guidance for the protection of public health. HAs are not
enforceable Federal standards. HAs are concentrations of a substance in
drinking water estimated to have negligible deleterious effects in humans, when
ingested, for a specified period of time. Exposure to the substance from other
media is considered only in the derivation of the lifetime HA. Given the
absence of chemical-specific data, the assumed fraction of total intake from
drinking water is 20%. The lifetime HA is calculated from the Drinking Water
Equivalent Level (DWEL) which, in turn, is based on the Oral Chronic Reference
Dose. Lifetime HAs are not derived for compounds which are potentially
carcinogenic for humans because of the difference in assumptions concerning
toxic threshold for carcinogenic and noncarcinogenic effects. A more detailed
description of the assumptions and methods used in the derivation of HAs is
provided in the Health Advisory Background Document.
ONE-DAY HEALTH ADVISORY FOR A CHILD
Note: Appropriate data for calculating a One-day HA are not available. It is
recommended that the Ten-day HA of 0.06 mg/L be used as the One-day HA.
TEN-DAY HEALTH ADVISORY FOR A CHILD
HA: 6E-2 nig/liter
LOAEL: 6.25 mg/kg-day
UF: 1000 allows for interspecies and intrahuman variability with
the use of a LOAEL from an animal study
Assumptions: l L/day water consumption for a 10-kg child
Principal Study: Ambrose et al., 1953
Discussion: The toxic effects in rats resulting from daily gastric intubation
of Chlordane at doses of 6.25, 12.5, 25.0, 50.0, 100.0, or 200 mg/kg for 15
days were histologic changes in the liver of the treated animals at all dose
levels and central nervous system effects at higher dose levels. Only minimal
histopathologic changes characterized by the presence of abnormal intra-
cytoplasmic bodies of various diameters were evident at the lowest dose level
(6.25 mg/kg). That dose level was identified as the LOAEL in this study.
LONGER-TERM HEALTH ADVISORY FOR A CHILD
Note: Appropriate data for calculating a Longer-term HA are not available. It
is recommended that the modified DWEL (adjusted for a 10-kg child) of 0.5 ug/L
be used as the Longer-term HA.
LONGER-TERM HEALTH ADVISORY FOR AN ADULT
Note: Appropriate data for calculating a Longer-term HA are not available. It
is recommended that the DWEL of 2 ug/L be used as the Longer-term HA for the
70-kg adult.
-------
Chlordane DWHA-2
————___= DRINKING WATER HEALTH ADVISORIES ————————i
DRINKING WATER EQUIVALENT LEVEL / LIFETIME HEALTH ADVISORY
DWEL: 2E-3 ing/liter
Basis: Oral RfD verified on: 03/22/89
Lifetime HA: None ing/liter
Assumptions: 2 L/day water consumption for a 70-kg adult
Principal Study: Velsicol Chemical Corporation, 1983
Discussion: See oral RfD. Chlordane is considered to be a probable human
carcinogen. Refer to the carcinogenicity assessment for information on the
carcinogenicity of this substance.
ORGANOLEPTIC PROPERTIES
No data available
ANALYTICAL METHODS FOR DETECTION IN DRINKING WATER
Determination of Chlordane is by a liquid-liquid extraction gas
chromato-graphic procedure.
WATER TREATMENT
Treatment technologies which are capable of removing chlordane from drinking
water include adsorption by granular or powdered activated carbon and air
stripping.
EPA DOCUMENTATION AND REVIEW OF HAS
Source Document: U.S. EPA. 1985. Final Draft of the Drinking Water Criteria
Document on Chlordane. Office of Drinking Water, Washington, DC.
EPA review of HAs in 1985.
Public review of HAs following notification of availability in October, 1985.
Scientific Advisory Panel review of HAs in January, 1986.
EPA CONTACTS
Jennifer Orme Zavaleta / OST — (202)260-7586
Edward V. Ohanian / OST — (202)260-7571
BIBLIOGRAPHY
Ambrose, A.M., H.E. Christensen, D.J. Robbins and L.J. Rather. 1953.
Toxi-cological and pharmacological studies on chlordane. Arch. Ind. Hyg.
Occup. Med. 7: 197-210.
U.S. EPA. 1985. Final Draft of the Drinking Water Criteria Document on
Chlordane. Office of Drinking Water, Washington, DC.
Velsicol Chemical Corp. 1983. MRID No. 00138591. Available from EPA. Write
-------
Chlordane DWHA-3
—————— DRINKING WATER HEALTH ADVISORIES —^——
to FOX, EPA, Washington, DC 20460.
REVISION HISTORY
03/88 HA Data: ' Health Advisory added
08/90 HA Contact: Primary contact changed
08/90 HA DWEL: DWEL changed reflecting change in RfD
-------
Chlordane
U.S. EPA REGULATORY ACTIONS
Regs-1
Substance Name:
CASRK:
Chlordane
57-74-9
EPA risk assessments nay be updated as new data are published and as assessment
methodologies evolve. Regulatory actions are frequently not updated at the
same time. Compare the dates for the regulatory actions in this section with
the verification dates for the risk assessments in the Oral RfD, Inhalation RfC
and Carcinogen Assessment Sections, as this may explain inconsistencies. Also
note that some regulatory actions consider factors not related to health risk,
such as technical or economic feasibility. Such considerations are indicated
for each action. In addition, not all of the regulatory actions listed in this
section involve enforceable federal standards. Please direct any questions you
may have concerning these regulatory actions to the U.S. EPA contact listed for
that particular action. Users are strongly urged to read the background
information on each regulatory action in the Regulatory Action Background
Document.
SAFE DRINKING WATER ACT (SDWA)
Maximum Contaminant Level Goal
Value:
Status/Year:
Econ/Tech?:
Reference:
Contact:
0 mg/L
Final 1991
No, does not consider economic or technical feasibility
56 FR 3526 (01/30/91)
Health and Ecological Criteria Division / (202)260-7571
Safe Drinking Water Hotline / (800)426-4791
Discussion: An MCLG of 0 mg/L for Chlordane is promulgated based upon
carcinogenic effects (B2).
Maximum Contaminant Level (MCL)
Value:
Status/Year:
Econ/Tech?:
Reference:
Contact:
0.002 mg/L
Final 1991
Yes, does consider economic or technical feasibility
56 FR 3526 (01/30/91)
Drinking Water Standards Division / OGWDW / (202)260-7575
Safe Drinking Water Hotline / (800)426-4791
Discussion: EPA has set a MCL equal to the PQL of 0.002, which is associated
with a lifetime individual risk of 1.5E-4.
Monitoring Requirements
All systems monitored for four consecutive quarters every 3 years; repeat
monitoring dependent upon detection, vulnerability status and system size.
-------
Chlordane Regs-2
—————————= U.S. EPA REGULATORY ACTIONS ———————
Analytical Methods
Microextraction/gas chromatography (EPA 505): electron-capture/gas
chromatography (EPA 508); gas chromatography/mass spectronetry (EPA 525): PQL-=
0.002 mg/L.
Best Available Technology
Granular activated carbon.
CLEAN WATER ACT (CWA)
Ambient Water Quality Criteria for Human Health
Water & Fish: 4.6E-4 ug/liter
Fish Only: 4.8E-4 ug/liter
Econ/Tech?: No, does not consider economic or technical feasibility
Reference: 45 FR 79318 (11/28/80)
Contact: Criteria and Standards Division / OWRS / (202)260-1315
Discussion: For the maximum protection from the potential carcinogenic
properties of this chemical, the ambient water concentration should be zero.
However, zero may not be obtainable at this time, so the recommended criteria
represents an E-6 estimated incremental increase of cancer risk over a
lifetime.
Ambient Water Quality Criteria for Aquatic Organisims
Acute Chronic
Freshwater: 2.4E+0 ug/L 4.3E-3 ug/L
at any time 24-hour avg.
Marine: 9.0E-2 ug/L 4.OE-3 ug/L
at any time 24-hour avg.
Econ/Tech?: No, does not consider economic or technical feasibility
Reference: 45 FR 79318 (11/28/80)
Contact: Criteria and Standards Division / OWRS / (202)260-1315
Discussion: Criteria were derived from a minimum data base consisting of acute
and chronic tests on a variety of species. Requirements and methods are
covered in the reference to the Federal Register.
FEDERAL INSECTICIDE, FUNGICIDE, AND RODENTCIDE ACT (FIFRA)
Pesticide Active Ingredient Registration Standard
Status: Issued 1986
Reference: Chlordane Pesticide Registration Standard. December, 1986 (NTIS
No. PB87-175816).
-------
Chlordane Regs-3
—————— U.S. EPA REGULATORY ACTIONS —————
Contact: Registration Branch / OPP / (703)305-5447
Pesticide Active Ingredient Special Review
Action: Cancellation of specified uses
Year: 1988
Econ/Tech?: Yes, does consider economic or technical feasibility
Reference: 43 FR 12372 (03/24/78); 52 FR 42145 (11/03/87); 53 FR 11798
(04/08/88)
Contact: Special Review Branch / OPP / (703)308-8010
Summary of Regulatory Actions: Cancellation of many termiticide products. 43
FR 12372 (03/24/78) - Cancellation of all but termiticide use; under the
provisions of the Administrator's acceptance of the settlement plan to phase
out certain uses of chlordane, most registered products containing chlordane
were effectively canceled or the applications for registration were denied by
12/31/80. A summary of those uses not affected by this settlement, or a
previous suspension, follows: 1) subsurface ground insertion for termite
control (clarified by 40 FR 30522, July 21, 1975, to apply to the use of
emulsifiable or oil concentrate formulations for controlling subterranean
termites on structural sites such as buildings, houses, barns, and sheds, using
current control practices), 2) dipping of nonfood roots and tops./52 FR 42145
(11/03/87) - Negotiated agreement on termiticide use. The agreement (order)
accepted voluntary cancellations of the registration of certain pesticide
products and imposed limitations on the continued sale, distribution, and use
of existing stocks of such products/ criterion of concern: oncogenicity,
RESOURCE CONSERVATION AND RECOVERY ACT (RCRA)
Appendix IX Listing for Land Disposal
Status: Listed 1987
Reference: 52 FR 25942 (07/09/87)
Contact: RCRA/Superfund Hotline / (800)424-9346 / (202)260-3000
SUPERFUND (CERCLA)
Reportable Quantity for Accidental Release
Value: 1 pounds
Status/Year: Final 1989
Econ/Tech?: No, does not consider economic or technical feasibility
Reference: 54 FR 33418 (08/14/89)
-------
Chlordane Regs-4
i—^—•—•—————= U.S. EPA REGULATORY ACTIONS I
Contact: RCRA/Superfund Hotline / (800)424-9346 / (202)260-3000
Discussion: The RQ for chlordane is 1 pound, based on aquatic toxicity, as
established under CWA Section 311 (40 CFR 117.3). Available data indicate the
aquatic 96-hour Median Threshold Limit for chlordane is less than 0.1 ppa. This
corresponds to an RQ of 1 pound. Chlordane has also been found to
bioaccumulate in the tissues of aquatic and marine organisms, and has the
potential to concentrate in the food chain.
REVISION HISTORY
08/90 Reg RCRA: EPA contact changed
01/92 Reg Data: Regulatory actions updated
-------
Chlordane
SUPPLEMENTARY DATA
Suppl-1
Substance Name:
CASRN:
Chlordane
57-74-9
The information contained in this section has been extracted from the EPA
Chemical Profiles Database, which has been compiled from a number of secondary
sources and has not undergone formal Agency review. The complete reference
listings for the citations in this section are provided in the Supplementary
Data Section Background Document. The user is urged to read this background
document for further information on the sources and limitations of the data
presented here.
ACUTE HEALTH HAZARD INFORMATION
TOXICITY:
A fatal oral dose to adult humans is between 6 and 60 g, with onset of
symptoms within 45 minutes to several hours after ingestion, although
symptoms have occurred following very small doses either orally or by skin
exposure. There were some reports of delayed development of liver disease,
blood disorders and upset stomach. Chlordane is considered to be borderline
between a moderately and highly toxic substance (Gosselin et al., 1984, p.
III-108-109). :
MEDICAL CONDITIONS GENERALLY AGGRAVATED BY EXPOSURE:
not found
SIGNS AND SYMPTOMS OF EXPOSURE:
Increased sensitivity to stimuli, tremors, muscular incoordination, and
convulsions with or without coma (Gosselin et al., 1984, p. III-108-109).
Chemical Formula:
Molecular Weight:
Boiling Point:
Spec. Gravity (H20=l):
Vapor Pressure (mmHg):
Melting Point:
Vapor Density (air=l):
Evap Rate (butylAc=l):
Solubility in Water:
Flash Point (method):
Flammable Limits:
LEL:
UEL:
Appearance:
CHEMICAL AND PHYSICAL PROPERTIES
C10H6C18
409.80
347F, 175C at 2 mmHg (Sunshine, 1969)
1.56-1.57 at 25C/OC (Merck, 1983)
1 x 10-5 at 25C (Sunshine, 1969)
not found
not found
not found
Insoluble (Merck, 1983)
not found
Flammable/combustible (DOT, 1984)
Not Found
not found
Amber viscous liquid with an aromatic, slightly pungent
odor (Merck, 1983; CHRIS, 1978).
CONDITIONS AND MATERIALS TO AVOID:
Chlordane loses chlorine in the presence of alkaline reagents and should not
be formulated with any solvent, carrier, diluent, or emulsifier which has
-------
Chlordane Suppl-2
——1^—^—. SUPPLEMENTARY DATA i
alkaline reaction (Merck, 1983).
HAZARDOUS DECOMPOSITION OR BYPRODUCTS:
Chlordane degrades under natural environmental conditions to photoisomers,
such as photo-cis-chlordane, which are more toxic to certain animals than
Chlordane and also showed higher bioaccunulation (Khan et al., 1970).
MAJOR USES
As of 1983, the only use for Chlordane in the U.S. is for termite control
(IARC, 1972-1985). Chlordane was previously used as an agricultural hone and
garden pesticide or insecticide (SRI, 1983).
-------
Tetrachloroethvlene rperchloroethvlene. PERC1 (CASRN 127-18-4)
The carcinogenicity characterization has a long history. A
July 1985 Health Assessment Document for Tetrachloroethylene
(Perchloroethylene), EPA # 600/8-82/005F, classified the agent in
Weight-of-Evidence Group "C - Possible Human Carcinogen" mentioning
that this would be reevaluated because of new information. The
1985 document also provided upper bound inhalation and oral risk
estimates. An April 1987 Addendum to the Health Assessment
Document, EPA# 600/8-82/005FA, proposed that the Weight-of-Evidence
be upgraded to "B2 - Probable Human Carcinogen" and provided a
revised inhalation risk estimate. A February 1991 document titled
Response to Issues and Data Submissions on the Carcinogenicity of
Tetrachloroethylene, EPA# 600/6-91/002A discussed newer data
relative to weight-of-evidence classification. The Agency's
Science Advisory Board has reviewed these documents finding them to
be technically adequate while offering an opinion that the weight-
of-evidence is on C-B2 continuum (C=Possible Human Carcinogen,
B2=Probable Human Carcinogen). At present time, the Agency has not
adopted a final position on the weight-of-evidence classification.
The upper bound risk estimates from the 1985 Health Assessment
Document as amended by updated inhalation values from the 1987
Addendum have not as yet been verified by the IRIS-CRAVE Workgroup.
The estimates are viewed as useful information in the context of
the information available in the 1985-1987 period.
ORAL: 1985 HAD; Unit risk = 1.5E-6 per ug/L
Slope Factor = 5.2E-2 per mg/kg/day
INHALATION: 1987 Addendum; Unit risk = range form 2.9E-7 to
9.5E-7 with a geometric , mean of
5.8E-7 per ug/cu.m
Slope factor = 2.0E-3 per mg/kg/day
Those needing to make a choice about carcinogenicity have
found the 1985, 1987 and 1991 EPA documents and the 1988 and 1991
Science Advisory Board letters of advice useful background
information. When the Agency makes a decision about weight-of-
evidence, the CRAVE-IRIS verification will be completed and the
information put on IRIS.
-------
vyEPA
United States
Environmental Protection
Agency
Off ice of
Solid Waste and
Emergency Response
Publication 9345.0-051
September 1991
ECO Update
Office of Emergency and Remedial Response
Hazardous Site Evaluation Division (OS-230)
Intermittent Bulletin
Volume 1, Number 1
The Role of BTAGs in Ecological Assessment
Most EPA Regions have established groups of scientists to
advise and assist site managers with ecological studies pro-
duced in conjunction with Remedial Investigations and
Feasibility Studies (RI/FSs) andRemoval Actions atSuperfund
sites. In general, these groups are known as Biological Tech-
nical Assistance Groups or BTAGs, although some Regions
use different names. This Bulletin summarizes the BTAG
structure and function in the Superfund process. Its purpose
is to help site managers understand how BTAGs can assist
with the collection and evaluation of site information and
ensure that ecological effects are properly considered.
Why BTAGs?
The Comprehensive Environmental Restoration, Compen-
sation, and Liability Act (CERCLA), and the National Oil and
Hazardous Materials Contingency Plan (NCP) mandate that re-
medial actions at hazardous waste sites protect both human health
and the environment. In December 1988, the Directors of EPA's
Office of Emergency and Remedial Response (OERR) and Office
of Waste Programs Enforcement (OWPE) issued a memorandum
directing Regional Offices to perform "thorough and consistent"
ecological assessments at all Superfund sites. The memorandum
also encouraged the Regions to establish BTAGs, and EPA
Headquarters policy continues to support the BTAG process as a
means of ensuring quality ecological assessments.
Every site presents a unique combination of biological,
hydrological, geological, and chemical characteristics. Site man-
agers are responsible for overseeing a wide range of activities and
cannot be expected to have expertise in all the necessary scientific
areas. BTAGs serve a valuable function in providing the necessary
advice and review of ecological information.
The Superfund Environmental Evaluation Manual,1 issued in
1989, was intended specifically to be. used in conjunction with a
consultative framework such as that provided by BTAGs. It was
designed to provide an overview of the scientific and regulatory
basis for conducting ecological assessments, and to direct site
managers to Regional specialists (i.e., BTAGs) for assistance in
planning, designing, and conducting specific studies.
'U.S. Environmental Protection Agency, Risk Assessment
Guidance for Superfund, Volume II: Environmental Evaluation
Manual (EPA/540-1-89/001), 1989.
IN THIS BULLETIN
Why.BTAGs? 1
The BTAG Coordinator 2
Who Is on the BTAG? 2
What Does the BTAG Do? 2
What the BTAG Will Not Do 4
How to Work with the BTAG 4
ECO Update is a Bulletin series on ecological assessment of Superfund sites. These Bulletins serve as supplements to Risk Assessment Guidance
for Superfund, Volume I] .'Environmental Evaluation Manual (EPA/540-1-89/001). The information presented is intended as guidance to EPA and
other government employees. It does not constitute rulemaking by the Agency, and may not be relied on to create a substantive or procedural right
enforceable by any other person. The Government may take action that is at variance with these Bulletins.
-------
The STAG Coordinator
The STAG Coordinator is a person within EPA Regional
staff that maintains the logistics of the BTAG. In some Regions,
this responsibility is shared by more than one individual
Coordinators maintain regular contact with BTAG members,
provide necessary documentation to members prior to upcoming
reviews, and work directly with site managers. BTAG Coordinators
also maintain frequent communication with their Regional coun-
terparts to share techniques and ideas.
In some instances, Coordinators screen sites to determine the
need and/or extent of BTAG involvement. Sites requiring no
ecological assessment will not be brought before the group, thereby
saving review time by focusing the membership on those sites
requiring their attention.
Who Is on the BTAG?
BTAGs represent a variety of disciplines, including wildlife
biology, fisheries, soil science, aquatic toxicology, ecology, geol-
ogy, hydrology, risk assessment, and wetlands science. The spe-
cific composition of each BTAG varies from Region to Region.
The core of the BTAG membership usually includes the BTAG
Coordinator, plus staff from the Regional Environmental Services
Division who specialize in environmental monitoring, surveillance,
and assessment.
Several BTAGs typically include the National Environmen-
tal Policy Act (NEPA) coordinator, a member of the OERR's
Environmental Response Team or Toxics Integration Branch, and
biologists from other EPA Program Offices such as Wetlands,
Water, and Air. Other Federal agencies frequently represented on
BTAGs include the National Oceanic and Atmospheric Admin-
istration, the U.S. Department of the Interior, the U.S. Fish and
Wildlife Service, the U.S. Geological Survey, and the USD A
Forest Service. Some BTAGs may include representatives from
State agencies.
Because of their scientific expertise, representatives of Natu-
ral Resource Trustee agencies typically are included on the BTAG.
These individuals are serving in a technical advisory capacity and
BTAG consultation does not constitute Trustee notification as
required by CERCLA. Site managers must still notify all au-
thorities who may be Trustees, in accordance with the law.
Who Is on the BTAG and
What Do They Do?
Possible Members:
• EPA-HWD/ESD, Wetlands, Water, NEPA
Coordinator
• U.S Fish and Wildlife Service
• National Oceanic and Atmospheric Administration
• State Agencies
• Others
Responsibilities:
Advise RPM on all aspects of ecological assessment
• Define scope
• Review Work Plan
• Review Draft Rl and FS
• Help select alternatives
• Review RD/RA Plans
• Provide Expert Testimony
What Does the BTAG Do?
Figure 1 summarizes the role of the BTAG in relation to the
site manager and contractor. The BTAG functions primarily in an
advisory and review capacity, although individual BTAG mem-
bers, or the agency they represent, may pro vide additional services
to support the ecological activities.
Most BTAGs meet monthly, usually for a period of one to two
days. Meeting agendas vary from month to month, depending upon
the number of sites to review, individual site status, and time of
year (e.g., field season). Generally, 10 to 20 people participate in
BTAG meetings.
In some Regions, the BTAG operates within the formal
framework of a charter statement of purpose. Some of the advan-
tages noted by members of formal BTAGs include increased
efficiency of communication, an easily accessible record of meet-
ing events, and the assignment of specific roles and responsibili-
ties. In most cases, however, BTAG meetings remain informal or
semi-formal, depending on Regional operating policy.
The BTAG serves an advisory role; it functions to assist site
managers with the collection and evaluation of information needed
to assess ecological effects at Superfund sites. By performing this
advisory function, BTAGs help to ensure that CERCLA mandates
are met with regard to protection of the environment
The BTAG permits a peer review of ecological studies,
reaching consensus on recommendations made to site managers.
Without consultation of these experts as a group, solicitation of
input would be prohibitively lime-consuming, and the quality of
ecological assessments might not meet CERCLA mandates.
Continued on page 3
September 1991 • Vol. l.No.l
ECO Update
-------
Who Does What?
Figure 1
DIRECTS
ADVISES
ECOLOGICAL STUDY*
t
EPA CONTRACTOR
CONDUCTS
and
PREPARES
I
REVIEWS
* Ecological Study — Includes ecological assessments as pan" of the baseline risk assessment, ecological studies such as
toxicity tests and field studies, evaluation of remedial alternatives, ecological portions of RODs, and ecological plans.
BTAGs serve several essential functions to ensure adequate
consideration of ecological issuesatSuperfund sites. These include:
• Initial site review,
• Assistance in developing a work scope,
• Review of contractor qualifications and performance,
• Review of interim and final products,
• Evaluation of remedial alternatives, and
• Advice on remedial decisions, remedial design,
and remedial actions.
Initial Site Review
BTAGs can facilitate the early stages of the remedial process
by screening initial site data from such sources as the Preliminary
Assessment and Site Investigation to determine the nature and
extent of an ecological assessment. BTAG screening of initial site
data can help streamline the remedial process by ensuring that
ecological investigations are pertinent to remedial objectives. For
example, based on a review of environmental concentrations of
site contaminants in various media, the BTAG will only recom-
mend relevant exposure pathways for further study.
Assistance in Developing a Work Scope
An important role for the BTAG membership involves assist-
ing the site manager with scoping the ecological assessment effort.
BTAG involvement in the preparation, review, and approval of
work plans ensures that ecological work is focused, performed in
a timely manner, and technically correct. Specifically, BTAGs can
recommend study objectives, field and laboratory protocols, QA/
QC requirements, and other elements of a wo± plan. Because of
their direct experience, the BTAG members may also help identify
qualified investigators to perform ecological assessment.
The BTAG also can assist in the initial identification of
ecological Applicable or Relevant and Appropriate Requirements
(ARARs).
Review of Contractor Qualifications and
Performance
BTAGs can assist the site manager by reviewing and com-
menting on contractor qualifications and performance. Product
quality depends not only on the company performing or overseeing
the activity but on the experience of the personnel within that
company responsible for the product. BTAG involvement can help
ensure adequate contractor performance beginning early in the
process. For example, an inadequately prepared work plan may
indicate that the contractor does not have the necessary expertise
available to carry out the requisite ecological investigations. If
contractor expertise is lacking, the,BTAG may be able to identify
resources to carry out the needed work. BTAG consultation also
can facilitate communication between the site manager and the
contractor.
Review of Interim and Final Products
Site managers can use the BTAG to review and evaluate
interim products that include ecological studies. Based on the data
in such a product, the BTAG may recommend modifications to the
original work scope. This kind of "mid-course correction" can
save a project time and money.
Continued on page 4
ECO Update
September 1991 • Vol. l.No.l
-------
The BTAG can make recommendations for additional data
following the initial review. If the initial data are incomplete, the
BTAC can recommend the types of biological data (e.g., field
studies, toxicity tests) needed to characterize the ecological risks
posed by the site. For example, the BTAG may recommend
collection of more data on site chemistry, habitat identification, or
other information that will allow them to determine the need for,
and extent of, biological data.
The BTAG should review the draft and final ecological
assessment to ensure that this portion of the Remedial Investiga-
tion has been completed in an acceptable manner. Because eco-
logical assessment has no standardized methods for evaluating
risk, informed professional judgment is necessary to determine if
the weight of evidence supports a particular set of conclusions.
BTAG endorsement of the final ecological assessment will indi-
cate to approving authorities that ecological concerns have been
adequately addressed
Evaluation of Remedial Alternatives
BTAG involvement in the evaluation of remedial alternatives
ensures the protection of environmental receptors. The collective
expertise of the BTAG can be used to assess the adequacy of the
ecological-effects evaluation for each alternative. BTAG review
of alternatives also can ensure that ecologically related ARARs are
addressed.
Advice on Remedial Decisions, Remedial
Design, and Remedial Actions
BTAG involvement continues to be important during the
remedial design (RD) and remedial action (RA) phases. The
BTAG can evaluate the quality and completeness of work plans,
and advise on remediation and monitoring activities. BTAG par-
ticipation in this phase ensures that ROD and CERCLA mandates
are met.
For example, the ROD for a site recently undergoing RD
required creation of a new wetland. Within the body of the ROD
and associated documents were specific guidelines as to the
wetland design, plant species required, methods required to plant
vegetation to ensure desired growth, etc. However, BTAG review
of thecontractor'sworkplan showed that very few of the necessary
ecological requirements were addressed: plant species were not
specified, proper planting methods were missing, etc. Further-
more, the plan did not include the participation of a wetland
scientist. The BTAG recommended that the specific requirements
of the ROD be achieved by inclusion of a qualified wetland
scientist to ensure that the remedial objectives would be achieved.
In at least two Regions, the Superfund Division Director will
not sign a Record of Decision (ROD) unless the BTAG has
reviewed the site. In other Regions, RPMs are expected, but not
necessarily required, to obtain BTAG review before submitting
RODs for approval.
Finally, the BTAG can assist with the development of plans
to monitor ecological effects as sites move into the post-remedial
monitoring stage. Regular review of monitoring data by the BTAG
will help the RPM continue to see that ROD requirements are met
What the BTAG Will Not Do
The BTAG functions in an advisory capacity; as such it does
not, as a group, provide direct field or laboratory services. In
specific cases, it may be possible to make arrangements (such as
inter-agency agreements in thecaseofnon-EPAstaff) for individual
BTAG members to become directly involved in conducting por-
tions of the investigation.
The BTAG does not normally communicate directly with
responsible parties or their contractors. Advice is provided directly
to the site managers.
The BTAG does not write work plans and protocols, nor does
it conduct risk assessments. As an advisory group, the BTAG
functions to assist the site management process by reviewing and
commenting on sampling and analysis plans, ecological risk
assessments, and ecological implications of remedial decisions.
The BTAG focuses resources on site-specific requirements by
performing a quality assurance/quality control function on a
continuing basis.
How to Work with the BTAG
Consultation with the BTAG should follow the phased ap-
proach of site management At appropriate stages throughout the
RI/FS process, the site manager should use BTAG assistance and
advice to coordinate and monitor ecological studies. This consul-
tation allows for periodic re-assessment of goals and objectives,
and ensures a focused and high-quality investigation.
The first line of communication is the BTAG Coordinator,
who can convene meetings and help the site manager select
appropriate data for BTAG review. When the BTAG initially
considers a site, the site manager should provide a brief oral
presentation of the site history. Before the meeting, members
should be provided copies of relevant documents and reports.
Without exception, the quality of BTAG help is directly related to
their timely receipt of site data. D
This Bulletin has described in general terms how the BTAG can ensure that ecological concerns are
properly addressed in the Superfund process. To be certain that CERCLA mandates regarding protection
of the environment are met, site managers should consult their Regional BTAG Coordinator at the earliest
possible stage of the site assessment
September 1991 • Vol. l.No.l
ECO Update
-------
&EPA
United States
Environmental Protection
Agency
Off ice of
Solid Waste and
Emergency Response
Publication 9345.0-051
December 1991
ECO Update
Office of Emergency and Remedial Response
Hazardous Site Evaluation Division (OS-230)
Intermittent Bulletin
Volume 1, Number 2
Ecological Assessment of Superfund
An Overview
This document is the second issue of the ECO Update
series of Intermittent Bulletins, published by the Toxics
Integration Branch, Hazardous Site Evaluation Division,
Office of Emergency and Remedial Response. Practical
experience with the process of ecological assessment at
Superfund sites has pointed to the need for information and
guidance concerning both the scientific and management
aspects of ecological assessment. The ECO Update series is
intended to fill this need.
EcologicalAssessment of Superfund Sites: An Overview
is an updated framework for ecological assessment in the
Superfund program. As such, it offers a description of
ecological assessment components and a discussion of how
they fit into the Remedial Investigation and Feasibility
Study (RI/FS) process. Ecological assessment in the re-
moval process will be addressed in a future ECO Update.
The ECO Update Series
ECO Updates are a series of Intermittent Bulletins intended
to facilitate ecological assessment of Superfund sites. Each Bulle-
tin focuses on one aspect of ecological studies or ecological
assessment in the remedial process. Individual Bulletins may
discuss either technical methods or the management of ecological
assessments.
Limiting each Bulletin to a specific topic allows flexibility for
the user to select only those Bulletins that are applicable to the site
in question or the user's needs. For example, some sites do not
require toxicity tests, so investigators would not need to consult
Bulletins specific to testing. A user who needs only general
information on Natural Resource Trustees can refer to a specific
Bulletin on that topic and not have to look through a larger
document containing other, less relevant information.
The Bulletin series is written for both general and technical
audiences, which includes EPA site managers and staff, contrac-
tors. State personnel, and anyone else involved in the performance,
supervision, or evaluation of ecological assessments in Superfund.
Ecological assessment involves considerable professional
judgment. The ECO Updates assume that readers will confer
with qualified scientists for site-specific advice. These Bulletins
are not step-by-step guides on how to accomplish an assessment.
The series supplements the advisory process involving Regional
Biological Technical Assistance Groups (BTAGs). EPA staff
should consult their BTAG coordinator for more detailed infor-
mation on ecological assessment in their Region.
IN THIS BULLETIN
Background 2
What is an Ecological Assessment? 2
Ecological Assessment in the RI/FS Process 6
ECO Update is a Bulletin series on ecological assessment of Superfund sites. These Bulletins serve as supplements ID Risk Assessment Guidance
for Superfund. Volume II: Environmental Evaluation Manual (EPA/540-1 -89/001). The information presented is intended as guidance to EPA and
other government employees. It does not constitute rulemaking by the Agency, and may not be relied on to create a substantive or procedural right
enforceable by any other person. The Government may take action that is at variance with these Bulletins.
-------
Background
The Comprehensive Environmental Response, Compensa-
tion, and Liability Act (CERCLA), as amended, requires EPA to
remediate uncontrolled hazardous waste sites in ways that will
protect both human health and the environment. To fulfill this
mandate, the National Oil and Hazardous Materials Contingency
Plan (NCP) requires that the baseline risk assessment, which is
conducted during the Remedial Investigation and Feasibility Study
(RI/FS), "characterize the current and potential threats to human
health and the environment"' The NCP also specifies that
"[environmental evaluations shall be performed to assess threats
to the environment, especially sensitive habitats and critical habi-
tats of species protected under the Endangered Species Act"l
In December 1988, the Office of Emergency and Remedial
Response (OERR) and the Officeof Waste Programs Enforcement
issued a joint memorandum to Regional Divisions responsible for
Superfund, directing that "thorough and consistent" ecological
assessments be performed at all Superfund sites in both the
removal and remedial programs. In particular, the directive called
on the Regions to incorporate ecological assessmentinto the RI/FS
stage during development of the work plan, and to discuss the
ecological assessment in the Proposed Plan for site remediation.
To assist the Regions in implementing this policy, OERR
issued the S uperfund Environmental Evaluation Manual' in March
1989 to provide site managers with a general framework for
understanding the ecological assessment process. The manual is
predicated on the understanding that ecological assessment com-
bines careful observation, data collection, testing, and professional
judgment. Hence, the manual's principal goal is to introduce the
subject to site managers and encourage them to seek the advice and
assistance of the Regional BTAG?
What is an Ecological
Assessment?
The Environmental "Evaluation Manual defines ecological
assessment as:
. . . a qualitative andlor quantitative appraisal of the
actual or potential effects of a hazardous waste site on
plants and animals other than people or domesticated
species.
In practical terms, ecological assessment comprises four
interrelated activities:
• Problem Formulation—qualitative evaluation of contami-
nant release, migration, and fate; identification of contami-
nants of concern, receptors, exposure pathways, and known
ecological effects of the contaminants; and selection of
endpoints5 for further study.
• Exposure Assessment-—quantification of contaminant re-
lease, migration, and fate; characterization of exposure
pathways and receptors; and measurement or estimation of
exposure point concentrations.
• Ecological Effects Assessment—literature reviews, field
studies, and toxicity tests, Unking contaminant concentra-
tions to effects on ecological receptors.
• Risk Characterization—measurement or estimation of both
current and future adverse effects.
These components of ecological assessment are illustrated in
Figure 1. As the diagram indicates, each element in the process can
affect others. In reality, investigators frequently find that the
components do not always follow one another in a stepwise
manner, and may actually find themselves working on aspects of
all four components at the same time.
Problem Formulation
Problem Formulation defines the objectives and scope of the
ecological assessment. This componentofan ecological assessment
primarily involves a review of existing'data (including previous
studies of the site, such as the Preliminary Assessment, Site
Inspection, RI Field Investigation, and other sources). Its end
product is a conceptual model that identifies the environmental
values to be protected, the dataneeded, and the analyses to be used.
The problem formulation component may be difficult to
distinguish from exposure assessment or ecological effects assess-
ment. This situation arises from elements (e.g., effects andieceptors)
shared among these three components. Problem formulation dif-
fers from the other two components in the level of detail and
quantification. The difference lies in the distinction between
identification (Le., naming and listing) of these common elements
and characterization (Le., description and quantification). In
problem formulation, investigators:
• Focus on collecting preliminary information necessary to
design the exposure and ecological effects assessment, and
• Identify data needed to complete those assessments.
Continued on page 4
140 CFR Part 300.430 (d)(4).
2 40 CFR Part 300.430(e)(2)(i)(G).
5 U.S. Environmental Protection Agency, Risk Assessment Guidance for Superfund, Volume II: Environmental Evaluation Manual
(EPA/540-1-89/001), 1989.
* These groups are sometimes known by different names, depending on the Region, and not all Regions have established BTAGs.
Readers should check with the appropriate Superfund manager for the name of the BTAG coordinator or other sources of technical
assistance in their Region.
5 An endpoint is an expected or anticipated effect of a contaminant on an ecological receptor. Endpoints are discussed at greater length
in the section on Problem Identification.
December 1991 • Vol. l.No.2
ECO Update
-------
Ecological Assessment of Superfund Sites: Overview
Figure 1
PROBLEM FORMULATION
Qualitatively evaluate contaminant release, migration, and fate
Identify:
- Contaminants of ecological concern - Exposure pathways
• Receptors - Known effects
Select endpoints of concern
Specify objectives and scope
I
EXPOSURE ASSESSMENT
Quantify release, migration, and fate
Characterize receptors
Measure or estimate
exposure point concentrations
ECOLOGICAL EFFECTS
ASSESSMENT
• Literature
• Toxicity testing
• Reid studies
RISK CHARACTERIZATION
• Current adverse effects
• Future adverse effects
• Uncertainty analysis
• Ecological significance
I
REMEDIAL OBJECTIVES
ANALYSIS OF
REMEDIAL ALTERNATIVES
i
REMEDY SELECTION
RECORD OF DECISION
REMEDIAL DESIGN
REMEDIAL ACTION
ECO Update
December 1991 • Vol. l.No.2
-------
Qualitative Evaluation of Contaminant Release,
Migration, and Fate
Thic pnrtinn of prrfr4»m fiprmnlatinn fjfjarriliftg what it Irrmn/n
about contaminated media, contaminant movement, and the geo-
graphical fxtffnt of f-miMif aivi fomre c*Micyn'nst'oni Ecological
consideratkxisfbrcontaminamie]ease,migTadon.andfiateincfaide:
• Ground water discharge to surface water and wetlands,
• Transport of mntamiiiaf^ sediment,
• Runoff from and erosion of contaminated soils, and
• Bioaccumulation and bioconcentration.
Identification of Contaminants of Concern
Not all contaminants warrant equal attention with regard to
risk. Further, not all contaminants that pose human health risks are
important with respect to ecological risk — and vice versa. Factors
to consider in identifying a contaminant of ecological concern
include its:
• Environmental concentration in media (soils, surface wa- .
ter, ground water, sediments, air, and biota) representing
ecological exposure pathways;
• Frequency of occurrence, defining the prevalence of the
contaminant in site media;
• Background levels, indicating the concentrations that can-
not be attributed to the site;
• Unavailability, or presence in a form that can affect
organisms;
• Physical-chemical properties, such as volatility and
solubility;
'• Potential for bioaccumulation or bioconcentration, based
on its physical-chemical properties and its tendency to occur
in biota at higher concentrations than the surrounding
environment;
• Potency, or the amount of toxicant capable of producing
adverse effects; and
• Effects, such as acute lethality or sublethal responses (e.g.,
reproductive impairment).
Identification of Exposure Pathways
Based on the analysis of contaminant release, migration, and
fate, investigators identify potential exposure pathways for eco-
logical receptors. An exposure pathway is the link between a
contaminant source and a receptor. In evaluating exposure path-
ways, the analyst should consider all media (ground water, surface
water, sediments, soils, air, and biota) that are or could be contami-
nated. For example, exposure may be the result of direct contact
with contaminated media (e.g., dermal, uptake through gills.
ingestion) or exposure through the food chain. Investigators should
consider all potential receptors whenidentifying exposurepathways.
Identification of Receptors
Receptors are individual organisms, populations, or commu-
nities that can be exposed to a contaminant. Identification of
receptors arises from a review of the fate, migration, and potential
release of contaminants. Ecotogists begin by identifying poten-
tially exposed habitats on or near the site using a wide variety of
. including field rBconnaiwf'». yp^i photography, sat-
ellite imagery, and a review of previous studies to accomplish this i
task. As they identify potentially exposed habitats, ecologists
develop lists of species known or likely to occur in each habitat.
Identification of leceptcas should include:
• Species considered essential to, or indicative of, the healthy
functioning of the habitat (e.g., stream invertebrates);
• Rare, endangered or threatened species on or near the site; and
• Species protected under Federal or State law (e.g.. Migratory
Bird Treaty Act, Marine Mammal Protection Act).
Identification of Known Effects
Many sources, including data bases and publications, contain
information on ecological effects of contaminants. For example,
EPA's Ambient Water Quality Criteria (AWQQ Documents and
AQUatic Toxicity Information REtrieval (AQUIRE) data base
contain peer-reviewed data describing effects of contaminants on
aquatic (freshwater and marine) organisms. Data on terrestrial
effects and aquatic information not included in the AWQC docu-
ments or AQUIRE are available in the published literature. Where
appropriate, data on chemicals similar but not identical to site
contaminants can help characterize likely effects. Modeling tech-
niques. such as Quantitative Structure Activity Relationships
(QSAR), sometimes help in identifying surrogate chemicals for
data collection. These methods require specialized expertise to
ensure proper selection of surrogates and interpretation of results,
Site managers should obtain information from other invesn-
gations conducted on or near the site, to help target the ecological
assessment toward the most relevant questions. Examples of such
information include:
• Fieldor laboratory studies from previous investigations of the
site;
• Corroborated reports of unusual events such as fish kills,
other animal mortality, highly stressed vegetation, or absence
of species that experts would expect in the habitat; and
• Fish or wildlife consumption advisories issued by State or
local government agencies.
Selection of Endpolnts
Investigators next identify effects requiring further study.
These are known as endpoints.Riskassessors distinguish between
two types of endpoints. An assessment endpoint describes the
effects that drive decision making, such as reduction of key
populations or disruption of community structure. Measurement
endpoints approximate, represent, or lead to the assessment end-
point, using field or laboratory methods.' An assessment endpoint
often has more than one measurement endpoint associated with it.
Most studies have more than one set of assessmentand measurement
endpoints.
The critical step in selecting endpoints is deciding what
effects are important to remedial decision making. The assessment
' Glenn W. Suter n, "Ecological Endpoints," Chapter 2 in USEPA, Ecological Assessment of Hazardous Waste Sites: A Field and
Laboratory Reference (EPA/600/3-89A>13).
December 1991- Vol.1. No. 2
ECO Update
-------
endpoim should reflect a potentially significant ecological impact
Primary criteria for selecting measurement endpoints are based oo
their usefulness i" linking field or laboratory data to the assessment
endpoint.
For example, me assessment endpoint for a particular site
might be the probability of a significant reduction of a fish
population. The measurement endpoint used to arrive at such a
probability might be the chemical concentration shown to cause a
reduction in survival, growth, or reproduction in a standard labo-
ratory toxicity test
Ecologists often select more definitive site-specific measure-
ment and assessment endpoints during the exposure assessment
component. Information on contaminant migration, fate, and other
factors, discussed below under "Exposure Assessment," influ-
ences the choice of appropriate endpoints.
Specifying Objectives and Scope
The purpose of the activities described above is to identify the
preliminary objectives and scope of the ecological assessment and
additional data needed to complete the assessment This is critical
to the assessment process. It ensures that data collection, field
studies, laboratory tests, and the overall assessment can answer the
questions relevant to making remedial decisions.
Ecological assessment is an iterative process. As such, in-
vestigators often must revise the objectives and scope of the
ecological assessment as they collect and analyze site data. Using
such information, they can identify a need for more study, different
studies, or fewer studies.
Exposure Assessment
Exposure assessment quantifies the magnitude and type of
actual and/or potential exposures of ecological receptors to site
contaminants. The key dements in exposure assessment are
• Quantification of contaminant release, migration, and fate;
• Characterization of receptors; and
• Measurementorestimationofexposurepointconcentrations.
Exposure assessment often involves considerable effort and
technical expertise to complete. Site managers should consult with
their Regional 8TAG to identify specific approaches for evaluat-
ing ecological exposure.
Quantification of Release, Migration, and Fate
In the Exposure Assessment phase, investigators develop
estimates of current and future contaminant levels in affected
media, including all relevant spatial and temporal characteristics
of the contamination. These estimates can then be used to deter-
mine exposure point concentrations (discussed below).
Direct sampling of media yields information on the current
location and concentration of contaminants. Fate-and-transport
models predict the movement of contaminants from the source and
between media. Site managers should consult their BTAGs and
other Regional specialists about sampling design, sample place-
ment and timing, and the availability and selection of models
applicable to their sites.
Characterization of Receptors
Most sites requiring ecological assessments contain a large
number of species, populations, and communities—from microbes
to mammals from algae to trees. Evaluating risks for each and
every species present is impossible. To develop a reasonable and
practicableevaluation. the investigator focuses on alimitednumber
of receptors for the assessment. Ecologists select these receptors
based on the endpoints of concern and specific characteristics of the
site under study.
In characterizing receptors, investigators collect information
(primarily from published literature) on the species' feeding habits,
life histories, habitat preferences, and other attributes that could
affect their exposure or sensitivity to contaminants.
Exposure Point Concentrations
After identifying receptors, and selecting a subset of those
receptors, investigators estimate the concentration of contami-
nant^) in the media to which the receptors are exposed. This is
known as the exposure point concentration, which investigators
measure in the environmental medium or estimate using assump-
tions and/or fate-and-transport modeling.
The amount of contaminant a receptor takes in depends on
such factors as:
• The properties of the contaminant,
• The way the organism assimilates it (e.g., direct absorption,
ingestion).
• The nature of the receptor (e.g., behavior, life history), and
• The physical/chemical properties of the media (e.g., pH,
hardness, organic carbon content).
If a contaminant is known or expected to bioconcentrate or
bioaccumulate, investigators collect and analyze samples from
biota at two ormore trophic levels (e.g., plant, herbivore, carnivore)
along with surrounding media. Risk assessors use this information
in two ways:
• Directly, as exposure point concentrations for dietary expo-
sure pathways for ecological receptors; or
• Indirectly, for calculating site-specific bioconcentration fac-
tors (BCFs) or bioaccumulation factors (BAFs) to predict the
food-chain transfer of contaminants to organisms at higher
trophic levels.
Ecological Effects Assessment
This component concerns quantitatively linking concentra-
tions of contaminants to adverse effects in receptors. Literature
reviews, field studies, and/or toxicity testing provide this "dose-
response" information: thatis./uwmuc&toxicantisassociated with
how much of an adverse effect.
Literature Reviews
Organisms differ widely in their ability to tolerate toxicants,
depending on several factors, including environmental conditions.
the nature of the chemical, the age and reproductive status of the
organism, and inherent differences among species. Literature re-
ECO Update
December 1991 • Vol. 1. No 2
-------
views can provide specific dose-response information for the
species under study.
Dose-response information is useful in risk chari'Cff">ar'
-------
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ECO Update
December 1991-Vol. 1. No. 2
-------
Rl/FS Site Characterization
The Site Characterization phase of the SI^S reqnnes a
baseline risk assessment, which includes an «***??*] assess-
ment. The purposes of fh'g ecological aTu>*>f*'"fflt are to:
• Describe the observed or potential magnitude of adverse
ecological effects at the she and the primary cause of the
• Characterize the ecological consequences of the "no farther
action" remedial alternative.
Site managers should ensure that ecological studies for the
tion phase of site characterization.
Feasibility Study
Ecological information contributes to the Feasibility Study
(FS) process by assisting decision makers in the
selection of remedial alternatives. In developing preliminary
remediation goals (PRGs), investigaiors most address the results
of the ecological assessment and other ecological issues specified
in criteria, guidance, and applicable or relevant and appropriate
requirements (ARARs).
MOStFSS ggpmiiw nnmemiBt mm^frl •Itfmarivrx fa such
cases, site managers most screen the alternatives to narrow the
list that will be evaluated in detail The ecological assessment
helps this detailed analysis of alternatives by identifying risks or
benefits of each with respect to ecological receptors. The
analyses and conclusions of the ecological assessment can pro-
vide information on:
• The effectiveness of the alternative in reducing ecological
risks ayaviaf^l with contamination, and
• The ecological effects that may result from the remedial
action (e.g.» habitat destruction).
The ecological assessment can provide information for eco-
logical monitoring during remedial and post-remedial activities.
For detailed advice on applying ecological information to the FS
process, site managers should consult their Regional BTAGs. D
December 1991 • Vol. l,No.2
ECO Update
-------
f/EPA
United States
Environmental Protection
Agency
Off ice of
Solid Waste and
Emergency Response
Publication 9345.0-051
March 1992
ECO Update
Office of Emergency and Remedial Response
Hazardous Site Evaluation Division (OS-230)
Intermittent Bulletin
Volume 1, Number 3
The Role Of Natural Resource
Trustees In The Superfund Process
This Bulletin is intended to help Reme-
dial Project Managers (RPMs) and On-Scene
Coordinators (OSCs) work with natural resource
trustees during site assessment and remediation.
It explains the authority and responsibilities of
trustees, and the responsibilities of RPMs and
OSCs with respect to trustee issues. The goal of
this document is to help reduce delays and
ensure compliance with relevant statutes by
increasing understanding of trustee issues as
they pertain to the Superfund program.1
Authorities
CERCLA
The Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA), as
amended by the Superfund Amendments and Reau-
thorization Act (SARA) (Part 101, section 16), defines
natural resources as "land, fish, wildlife, biota, air,
water, ground water, drinking water supplies, and
othersuchresources." CERCLA designates the Presi-
dent of the United States as the trustee for Federally
protected or managed natural resources on behalf of
the public and requires the President tor
• Assess damages from releases of hazardous sub-
stances,
• Pursue recoveries of damages and costs, and
• Use the sums recovered to restore, replace, or
acquire the equivalent of the injured resource
(Section 107 (f)(l) of CERCLA).
in This Bulletin
Authorities 1
Who Are The Natural Resource Trustees? 2
What Is a Trust Resource? 5
Trustee Functions 6
How to Work With Trustees 9
Conclusion 11
1 All sections of this Bulletin have benefitted greatly from
material obtained from the Region 10 Natural Resource Trustee
Notification and Coordination Package (September 1989). The
Package was prepared by the National Oceanic and Atmo-
spheric Administration Coastal Resource Coordinator in coop-
eration with the Department of Interior Regional Environmental
Officer and the Region 10 Natural Resource Coordinator. Noti-
fication and coordination packages are also available in many
other EPA Regions.
ECO Update is a Bulletin series on ecological assessment of Supeifund sites. These Bulletins serve as supplements to Risk Assessment
Guidance for Superfund, Volume II: Environmental Evaluation Manual (EPA/540-1-89/001). The information presented is intended as
guidance to EPA and other government 'employees. It does not constitute rulemaking by the Agency, and may not be relied on to
create a substantive or procedural right enforceable by any other person. The Government may take action that is at variance with
these Bulletins.
-------
These functions are carried out by various
trsustees, as discussed later in this Bulletin.
The law also directs EPA to coordinate with
natural resource trustees. This coordination includes:
• Prompt notification of potential injuries to natu-
ral resources at Superfund sites and incidents
[§104(b)(2)];
• Coordination of assessments, investigations, and
planning [§104(b)(2)];
• Notification of negotiations with potentially re-
sponsible parties (PRPs), if the release of hazard-
ous substances may have resulted in injuries to
trust resources [§122(j)(l)]; and
• Encouraging trustees to participate in the nego-
tiations [§122(j)(l)].
National Contingency Plan
AscalledforinCERCLAsectionl07(f),subpart
G of the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP)2 designates the
heads of authorized Departments and agencies as
trustees for natural resources and defines their juris-
diction. The NCP also spells out the responsibilities
of the trustees following notification or discovery of
a natural resource injury, loss, or threat. Depending
on the stage in the remedial process and the nature of
the injury, loss, or threat, the trustees may do one or
more of the following, or "other actions as appropri-
ate"
(1)
(2)
(3)
(4)
Conduct a preliminary survey of the area af-
fected by the discharge or release to determine if
trust resources under their jurisdiction are, or
potentially may be, affected;
Cooperate with the OSC/RPM in coordinating
assessments, investigations, and planning;
Carry out damage assessments; or
Devise and carry out a plan for restoration,
rehabilitation, replacement, or acquisition of
equivalent natural resources.3
The NCP describes the trustees' authority as
including, but not limited to, the following actions:
(1) Requesting that the Attorney General seek com-
pensation from the responsible parties for the
damages assessed and for the costs of an assess-
ment and of restoration planning; and
(2) Participating in negotiations between the United
States and potentially responsible parties (PRPs)
to obtain PRP-financed or PRP-conducted as-
sessments and restorations for injured resources
or protection for threatened resources and to
agree to covenants not to sue, where appropri-
ate.4
The NCP also defines EPA responsibilities
with respect to natural resource coordination. EPA is
required to carry out the following notification and
coordination activities:
• Make available any information that can assist
trustees in determining injuries to natural re-
sources [§300.160(a)(3)]; and
• Coordinate with trustees in requiring PRPs to
comply with CERCLA information requests
[§300.615(d)(3)].
In addition, EPA may:
• Issue administrative orders to pursue injunctive
relief against PRPs at the request of the trustee
[§300.615(e)(l)]; and
• Conduct removal or remedial actions at the re-
quest of the trustee [§300.615(e)(2)].
Who Are The Natural Resource
Trustees?
By Executive Order 12580 and in the NCP, the
President has designated certain executive officers as
Federal trustees for natural resources. They include
the Secretaries of the Departments of Interior, Com-
merce, Defense, Energy and Agriculture. In addition,
SARA Section I07(d) requires the Governor of each
State to designate State trustees; most Governors
have done so. Indian tribes also are trustees for their
resources, functioning much as State trustees for re-
1 40 CFR Part 300.
3 40 CFR 300.615.
' 40 CFR 300.615.
March 1992 • Vol. I, No. 3
ECO Update
-------
sources on or related to tribal lands or for resources to
(which they otherwise may have treaty rights. Figure
1 summarizes the organization of trustee authority,
as discussed below.
Federal Trustees
Federal trustees are designated because of (a)
statutory responsibilities with regard to protection or
management of natural resources, or (b) manage-
ment of Federally owned land, or (c) both.
Secretary o f Commerce
The NCP desig-
nates the Secretary of Com-
merce as trustee for
... natural resources man-
aged orprotected by the De-
partment of Commerce or
by other federal agencies
and that are found in or
under waters navigable by
deep draft vessels, in or
under tidally influenced
waters, waters of the con-
tiguous zone, the exclusive
economic zone, and the
outer continental shelf,and
in upland areas serving as
habitat for marine mam-
mals and other protected
species— Examples of the
Secretary's trusteeship in-
clude marine fishery re-
sources and their support-
ing ecosystems; anadro-
mous fish [saltroater fish
that return to freshwater
streams to breed]; certain
endangered species and
marine mammals; and Na-
tional Marine Sanctuaries
and Estuarine Research Re-
serves.5
The Secretary of Commerce has delegated the
Administrator of the National Oceanic and Atmo-
spheric Administration (NO AA) to act as the Depart-
ment of Commerce natural resource trustee. To facili-
tate coordination between NOAA and EPA, NOAA
has placed Coastal Resource Coordinators in all of the
coastal EPA Regional Offices.
40 CFR 300.600.
Natural Resource Trustees
Figure 1
Federal
State
Indian Tribes
State Governor
designated:
State Official
Tribal Chairman
designated:
Individual
or request
DOI Bureau of
Indian Affairs
as trustee
Secretary of
Interior
delegated:
Regional
Environmental
Officer
Secretary of
Commerce
delegated:
NOAA
Administrator
Fish and Wildlife
U.S. Geological Survey
National Park Service
Minerals Management Service
Bureau of Reclamation
Bureau of Land Management
Bureau of Indian Affairs
ECO Update
March 1992 • Vol. 1, No. 3
-------
Secretary of the Interior
The Secretary of the Interior acts as trustee for
natural resources managed or protected by the De-
partment of the Interior (DOD.
Examples of the Secretary's trusteeship include mi-
gratory birds; certain anadromous fish, endangered
species, and marine mammals; federally owned min-
erals; and certain federally managed water resources.
The Secretary [is also] trustee for those natural re-
sources for which an Indian tribe would otherwise act
as trustee in those cases where the United States acts
on behalf of the Indian tribe.6
DOI has delegated Regional Environmental
Officers from the Office of the Secretary as the princi-
pal trustee contacts for their agency. The. Regional
Environmental Officer coordinates with the follow-
ing DOI bureaus on 'trustee concerns: the U.S. Geo-
logical Survey, Bureau of Mines, National Park Ser-
vice, Minerals Management Service, Bureau of Recla-
mation, Bureau of Land Management, Fish and Wild-
life Service, Bureau of Indian Affairs, Office of Sur-
face Mining Reclamation and Enforcement, and the
Office of the Solicitor.
In addition to fulfilling the Secretary's duties
as natural resource trustee, DOI is charged under
CERCLA with promulgating regulations for the as-
sessment of natural resource damages from releases
of hazardous substances. These regulations, foundat
43 CFR Part 11, are currently undergoing amend-
ment.
Secretaries for Land-Managing Agencies
The NCP designates as trustees the Secretar-
ies of Departments that manage Federally owned or
administered lands. The trusteeship applies to all
"natural resources located on, over, or under" these
lands. These land-managing agencies are co-trustees
with the Department of the Interior, Department of
Commerce, and/or possibly the State or Indian tribe
for most of the living natural resources. In addition to
the Secretary of the Interior, discussed above, these
trustees include the Secretaries of Agriculture, De-
fense, and Energy.
DOI is the largest Federal land-management
agency. Its land-management functions are carried
outbytheBureauofLandManagement(publiclands);^fe
National Park Service (parks and monuments), Fish^P
and Wildlife Service (wildlife refuges), and the Bu-
reau of Reclamation (waterprojects). The Secretary of
Agriculture, through the USDA Forest Service, has
jurisdiction over large tracts of land (the National
Forests) in all areas of the country. The Secretary of
Defense has trusteeship over all lands owned or
managed by the Department of Defense, including
facilities operated by the Navy, Army, Air Force, and
Defense Logistics Agency. The Secretary of Energy is
trustee for all lands owned or managed by the De-
partment of Energy.
Where Federal facilities contain uncontrolled
hazardous waste sites, the agency managing the prop-
erty may be held accountable as both the responsible
party and the natural resource trustee. Usually, how-
ever, the agency will be co-trustee with another Fed-
eral agency, and some of the potentially affected
resources may also be under the trusteeship of a State
or an Indian tribe. When the hazardous wastes are
not on Federal property, the land-managing agency's
trustee role may be exercised if contaminants from
the site threaten resources on Federal land. Th
could happen if, for example, a hazardous waste site
were located upstream of a Federal facility and the
stream transported contaminants onto the Federal
property.
State Trustees
According to CERCLA and the NCP, a State
may act as trustee for natural resources within the
boundaries of the State or for those resources belong-
ing to, controlled by, or appertaining to the State.
Each State governor is required under CERCLA to
designate State officials who will act as trustees.
Usually, that official heads the agency responsible for
environmental protection or resource conservation.
A complete list of State-designated trustees is avail-
able from EPA headquarters, DOI, and NOAA. If
there is any doubt as to who the State trustees are for
40 CFR 300.600.
March 1992 •Vol.1, No. 3
ECO Update
-------
a specific site, the site manager should contact one of
these offices or their counterpart State agency.
Indian Tribes
The tribal chairman, the head of the govern-
ing body of an Indian tribe, or a person selected by the
chairman or the head of the governing body, may act
as trustee on behalf of the tribe. This individual is
trustee for the natural resources belonging to, man-
aged by, controlled by, or appertaining to the tribe.
At the tribe's request, the DOI Bureau of Indian
Affairs may act as trustee on the tribe's behalf. If there
is any doubt as to whether there is an Indian tribal
trustee for a specific site, or who that trustee is, the site
manager should contact the DOI Regional Environ-
mental Officer.
Natural resources include "land,
fish, wildlife, biota, air, water,
ground water, drinking water
supplies, and other such re-
sources."
What Is A Trust Resource?
CERCLA Section 101 (16) defines trust re-
sources to include:
...land, fish, wildlife, biota, air, water, ground water,
drinking water supplies, and other such resources
belonging to, managed by, held in trust by, appertain-
ing to, or otherwise controlled by the United States
(including the resources of the exclusive economic
zone defined by the Magnuson Fishery Conservation
and Management Act of 1976), any state or local
government, any foreign government, any Indian
tribe, or if such resources are subject to a trust
restriction on alienation, any member of an Indian
tribe.
Trust resources include both species and
places. Fish, wildlife, migratory birds, and marine
mammals are all mentioned in CERCLA and the NCP
as trust resources, as are National Marine Sanctuaries
and Estuarine Research Reserves. DOI protects not
only endangered species but also National Parks and
Monuments. The Departments of Agriculture, De-
fense, and Energy are trustees for natural resources
that occur on their lands. In some cases, federal
agencies can be co-trustees for a particular natural
resource. Federal and State agencies also are fre-
quently co-trustees for natural resources.
Living Resources
In designating the Secretaries of Commerce
and Interior as natural resource trustees, the NCP
gives examples of the types of resources that fall
under the Secretaries' trusteeship. Included among
these are marine fishery resources, anadromous fish,
endangered species, migratory birds, and marine
mammals. In specifying marine fishery resources as
trust resources, the NCP adds the phrase "and their
supporting ecosystems." This acknowledges the fact
that protecting a living resource entails not only
preventing or mitigating contamination of the pro-
tected species itself but also ensuring the continued
availability and quality of that species' habitat and
food sources.
CERCLA and the NCP use the comprehen-
sive term "biota" and the specific term "fish [and]
wildlife" to define the living resources covered under
Federal trusteeship. The NCP cites more specific
types of resources such as anadromous fish, endan-
gered species, and marine mammals only as ex-
amples of trust resources, not as a definitive list
The clear implication of these references is that the
definition of what is a trust resource is left to the
trustee. To an extent, trustees' responsibilities may be
denned by the various statutes that they are charged
with enforcing or implementing, including the man-
agement of land under their control Within the
bounds of those statutes and land-managemenLre-
sponsibilities, trustees may interpret their CERCLA
mandate to include whatever biota "and their sup-
porting ecosystems" that the trustees consider appro-
priate. With regard to specific sites, the EPA site
manager should let the trustee agencies determine
ECO Update
March 1992 •Vol.1, No. 3
-------
whether trust resources are present and potentially
affected by a site.
Land, Air, Water, and Mineral Resources
In addition to living resources, CERCLA and
the NCP list "land, . . . air, water, ground water,
drinking water supplies, and other such resources"
as responsibilities of natural resource trustees. These
could include, for example, minerals controlled by
the Department of the Interior's Bureau of Land
Management, rivers protected under the Wild and
Scenic Rivers Act, coastal zone areas regulated or
administered by NOAA under the Coastal Zone
Management Act, and air quality over a National
Park. It is also important to remember that the phrase
"supporting ecosystem," as used in the NCP, implies
that protection of biotic resources often entails ac-
tions aimed at nonliving components of the environ-
ment. In fact, it is often difficult to separate living
from nonliving components, especially when soil,.
sediments, and surface water are involved. As with
living resources, the determination is best left to the
appropriate Federal, State, or Indian tribal represen-
tative as to whether a given nonliving resource is a
trustee responsibility.
Natural resource trustees have
a broad mandate to protect and
restore resources under their
jurisdiction. Therefore, the
responsibilities of the trustees
are not restricted to any single
point in the Superfund process.
Trustee Functions
Natural resource trustees have a broad man-
date to protect and restore resources under their
jurisdiction. Therefore, the responsibilities of the
trustees are not restricted to any single point in the
Superfund process. CERCLA Section 104(b)(2) calls
for coordination between EPA and trustees on "as-
sessments, investigations, and planning"; in other
words, at virtually all stages of the process. This
requirement applies to both the removal and reme-
dial actions, and to enforcement and Fund-lead sites.
Trustees' primary responsibilities include:
• Preliminary Natural Resource Survey (PNRS)
• Technical Assistance
• Natural Resource Damage Assessment (NRDA)
• Covenant Not to Sue
Preliminary Natural Resource Survey
(PNRS)
In accordance with the NCP §300.615 (c)(l),
and through Memoranda of Understanding between
EPA and both DOI and NOAA, EPA can request a
representative of one of these agencies to conduct a
PNRSoranotherformofpreliminarysitesurvey. The
request usually originates with the RPM, but it also
may come through a designated EPA Natural Re-
source Coordinator, or a Section or Branch Chief.
A PNRS consists of a site survey and a brief
report identifying the natural resources, habitat types,
endangered or threatened species, and any potential
adverse effects or injury to trust resources. The
PNRS, which may be funded by EPA, is an effective,
low-cost screening tool to determine if trust re-
sources are involved at a site. It may be conducted at
any stage of the remedial process, from pre-listing to
pre-Record of Decision (ROD).
The earlier the PNRS information is available,
the more likely it can be used to ensure that remedial
alternatives are selected which effectively protect
natural resources of concern to trustees. If the PNRS
is conducted before RI scoping, it may provide infor-
mation useful for sampling design and other aspects
of the RI /FS ecological assessment. If conducted after
completion of the RI and during the evaluation of
remedial alternatives for the FS, the PNRS may help
the trustees develop their position on a covenant not
to sue. Site managers should consult with trustee
representatives in their Region to determine the most
appropriate time(s) for performing the PtvTRS.
March 1992 • Vol. 1, No. 3
ECO Update
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Technical Assistance
While not a trustee responsibility tinder CER-
CLA, several trustee agencies offer technical assis-
tance at Superfund sites. As well as furthering EPA's
ecological assessments, such activities support the
trustees' larger role in safeguarding natural resources.
Advice and technical assistance from trustee repre-
sentatives can take many forms. In most EPA Re-
gional Offices, one or more trustee representatives
serve on Biological Technical" Assistance Groups
(BTAGs),7 which provide review and advice on eco-
logical issues in the assessment and remediation of
sites. Usually, trustee representatives are also avail-
able for individual consultation on technical issues.
Through Interagency Agreements, trustee agencies
often perform specific tasks relating to ecological
assessment of a site, such as field surveys, toxicity
testing, and detailed examination of field-collected
organisms. FWS staff or NOAA Coastal Resource
Coordinators in coastal EPA Regional Offices may
also act as a source of technical assistance for ecologi-
cal assessments in wetland and aquatic habitats.
It is important to understand that technical
assistance does not in any way commit a trustee to a
covenant not to sue. Furthermore, review of site
activities by trustees serving on the BTAG is not a
substitute for notification of the trustees.
Natural resource damages are
monetary payments "for injury
to, destruction of, or loss of
natural resources, including the
reasonable costs of assessing
such injury, destruction, or
loss..."
Natural Resource Damage Assessment
If remedial actions are judged insufficient to
protect and restore natural resources injured by re-
leases from a Superfund site, or if the use of a natural
resource is lost or curtailed, natural resource trustees
may seek to collect damages from responsible parties.
Natural resource damages are monetary payments
"for injury to, destruction of, or loss of natural re-
sources, including the reasonable costs of assessing
such injury, destruction, or loss resulting from such a
release."8 These payments are considered compensa-
tion, not punitive damages, and are intended to cover
the past injury and residual costs or losses beyond
whatever restoration can be achieved through
remediation. Only responsible party funds can be
used to pay natural resource damages; Superfund
monies cannot be used for this purpose.
EPA site managers must recognize that the
natural resource damage assessment process is the
responsibility of the trustee agencies, not of EPA. In
addition, EPA is not required to collect or fund the
collection of all the information needed to carry out a
natural resource damage assessment. In fact EPA
cannot collect information solely for the purpose of a
natural resource damage assessment. However, it is
equally important to remember that CERCLA and
the NCP require prompt notification of, and close
coordination with, the trustees. Coordination entails
timely exchange of information between EPA and the
trustees to ensure the technical adequacy of EPA's
selected remedy with respect to natural resources.
Selection of remedial alternatives that adequately
protect and restore natural resources will in most
cases reduce the likelihood of expensive and time-
consuming natural resource damage proceedings
which could delay negotiated settlements.
The Natural Resource Damage Assessment
(NRDA) process:
• Determines whether injury to, or loss of, trust
resources has occurred;
' These groups are sometimes known by different names, depending on the Region, and not all Regions have established BTAGs.
Readers should check with the appropriate Superfund manager for tne name orthe BTAG coordinator or other sources of technical
assistance in their Region. A more complete description of BTAG structure and function is available in The Role of BTAGs in Ecological
Assessment (ECO Update Vol. 1, No. 1).
' CERCLA Section l07(a)(4)(D).
ECO Update
March 1992 • Vol. I, No. 3
-------
• Ascertains the magnitude of the injury or loss;
• Calculates the dollar value of the injury, loss,
and/or cost of restoration; and
• Develops a restoration plan.
EPA can facilitate the resolution of natural
resource damage issues during the RI/FS by coordi-
nating with trustees to ensure that data useful to both
EPA and the trustees are collected. When properly
designed, the ecological assessment portion of the
RI/FS may help to determine whether:
• A discharge or release has occurred,
• Trust resources have been affected,
• Injury has occurred or is likely, and
• Planned remedial responses will or will not be
sufficient to protect or restore the resources.
Collection of this information serves the CER-
CLA requirement that EPA undertake investigations
to identify the extent of danger to the environment
from the release of contaminants. It also serves the
additional requirement in CERCLA Section 104(b)(2)
that EPA coordinate assessments, investigations, and
planning with Federal and State trustees. A well-
designed ecological assessment, then, is part of the
process of determining the extent and degree of con-
tamination. It is an essential part of the decision
making process as to the need for and scope of any
remedial action. In addition, it can provide the natu-
ral resource trustees with information to use during
their evaluation of possible injuries to trust resources.
Covenant Not to Sue
A trustee may choose to sue a responsible
party for the monetary damages calculated in the
NRDA plus the cost of conducting the assessment
Although this decision is wholly that of the trustee,
EPA's interest in the issue can be significant if nego-
tiations with responsible parties are contemplated or
in progress.
CERCLA Section 122(j) requires EPA to notify
Federal trustees of any negotiations regarding the
release of hazardous substances that may have re-
sultedinnaturalresource injury, whileSection 122(p(l)
calls on EPA to encourage Federal trustees to partici-
pate in negotiations with responsible parties. In those
cases where trustees believe that they will need more
information than EPA proposes to collect as part of
the ecological assessment, they can negotiate with the
responsible parties at the same time as EPA negoti-
ates for the RI/FS. Note that EPA does not have the
authority to negotiate on behalf of the trustees. In
addition, if in the settlement process the responsible
party requests a covenant not to sue for natural
resource injuries, only the natural resource trustee or
trustees, through the Department of Justice, can grant
such a covenant.
CERCLA Section 122(j)(2) provides the link
between remedial action decisions and the covenant
not to sue:
The Federal natural resource trustee may agree to
such a covenant if the potentially responsible party
agrees to undertake appropriate actions necessary to
protect and restore the natural resources damaged by
such release or threatened release of hazardous sub-
stances.
In other words, trustee concurrence with a
settlement—and, if appropriate, granting a covenant
not to sue—is most likely to be facilitated if the
selected remedial action will protect and restore trust
resources. However, it should be noted that a cov-
enant is not necessary for every Operable Unit at a
site, so long as the Consent Decree for the Remedial
Design/Remedial Action (RD/RA) retains the stan-
dard Reservation of Rights. The covenant is needed
if the PRP refuses to accept the Reservation and
requires a covenant not to sue as a condition of
settlement. In these circumstances, only the trustees
can agree to the covenant.
The trustee's first priority is to
see that remedies are selected
which protect and restore trust
resources.
March 1992 •Vol.1, No. 3
ECO Update
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How To Work With Trustees
As mentioned above, natural resource dam-
ages are considered residual damages. The trustee's
first priority is to see that remedies are selected which
protect and restore trust resources. To be reasonably
confident of obtaining a covenant not to sue, a site
manager should remain mindful of four important
responsibilities during the remedial process:
• Adherence to the notification and coordination
provisions of CERCLA, the NCP, and any Memo-
randa of Understanding between EPA and the
respective trustee;
• Consultation with the BTAG or its equivalent in
the design and implementation of the ecological
assessment portion of the RI/FS;
• Consultation with trustees on recommendations
for remedial alternatives; and
• Compliance with environmental applicable or
relevant and appropriate requirements (ARARs).
Notification
When to Notify
CERCLA Section 104(b)(2) requires EPA to
promptly notify natural resource trustees of the po-
tential for injuries resulting from releases under in-
vestigation. Section 122(j) requires notification re-
garding pending negotiations with potentially re-
sponsible parties. In practice, site managers should
treat notification as a process rather than a one-time
event. As the Superfund process unfolds at a site, the
RPM will become aware of which trustees may have
an interestin the site (see the following section, Whom
to Notify). Site managers should plan on notifying
trustees of such key events as:
• Site discovery,
• Preliminary Assessment/Site Inspection,
• Proposal of a site for inclusion on the National
Priorities List,
• Initiation of RI/FS negotiations,
• Receipt of the draft and final RI/FS workplans,
Receipt of the draft RI/FS or any relevant in-
terim product such as the ecological assessment
portion of the RI/FS,
Final RI/FS,
Completion of the draft ROD,
Final ROD,
Initiation of RD/RA negotiations, and
Receipt of the draft and final RD/RA workplans.
Notification should be in the form of a letter
indicating what activity is taking place or what prod-
uct is available. It could include copies Of relevant
documents for review, an invitation to attend a meet-
ing, or a request for specific action (such as review of
a document).
Whenever trustees are expected to take some
action, it is important that notification take place early
enough to allow the trustee to respond in a timely
manner, and that a date is stated by which comments
or actions are required. Notification should be
viewed not only as compliance with statutory re-
quirements, but as insurance toward keeping
projects on time and within budget
Whom to Notify
As discussed earlier, trusteeship has been delegated
to five Federal Departments: Interior, Commerce,
Agriculture, Defense, and Energy. The site manager
will need to decide which trustees to notify regarding
a specific site, based on where the site is located, what
habitats or Federally managed lands are potentially
exposed, and what species are potentially exposed.
The descriptions of each Department's trust-
eeship, also discussed earlier in the Bulletin, can be
used as a sort of checklist as to whom to notify.
However, since no checklist can be exhaustive, the
general rule should be: When iri doubt, notify. If the
site is not relevant to a particular agency's trustee-
ship, the trustee representative will inform the site
manager and np further notification will be needed.
The site manager should request that the trustee
provide a written response as to their interest, or lack
of interest, in a site.
A second general rule is, Always notify the
Department of Interior trustee representative and,
if there is one in your Region, the NOAA Coastal
Resource Coordinator. These two agencies have
responsibility in a wide variety of Superfund sites.
For example, since migratory birds can utilize almost
ECO Update
March 1992 • Vol.1, No. 3
-------
any terrestrial or aquatic habitat, DOI may be a trustee
at almost any site. In addition, an aquatic habitat that
is no longer fished may still come under the jurisdic-
tion of a natural resource trustee. Also, as described
earlier in this bulletin, the trusteeships of the two
Departments overlap considerably (e.g.,anadromous
fish,marmemarnmals,andendangeredspecies). DOI,
NOAA, and State/tribal representatives will be the
best judges as to whose trust resources are at issue
with regard to a particular site.
If there is any reason to suspect that the site
may affect National Forests, the site manager should
notify the USDA trustee representative. If property
controlled by the U.S. Army, Navy, Air Force, or
Defense Logistics Agency is potentially exposed to
contaminants, the Department of Defense trustee
representative should be notified. If the site contami-
nants might affect lands or resources controlled by
the Department of Energy, that agency's trustee rep-
resentative should be notified. EPA Headquarters,
DOI, or NOAA can assist in identifying the appropri-
ate individuals in each of these agencies for notifica-
tion purposes.
CERCLA also requires notification of State
trustees, and in addition the site manager should
notify Indian trustees where a site potentially affects
natural resources on Indian lands. Often, Federal
trust resources are a co-trusteeship with States and
Indian tribes. Most States have designated threat-
ened or endangered species that do not appear on the
Federal list. Trusteeship for other resources may be
limited to the State if their geographic distribution or
special value places them entirely within the State's
boundaries or jurisdiction. The site manager should
contact appropriate State liaisons to determine what
State trustee agencies to notify regarding a site. As
discussed earlier, EPA Headquarters, DOI, and NOAA
all maintain a list of State trustees, which may be
helpful in identifying appropriate offices for notifica-
tion. The DOI representative also should be able to
help site managers contact Indian tribal trustees or
the Bureau of Indian Affairs if tribal trust resources
are potentially affected.
Coordination
Coordination involves a two-way communi-
cation between EPA and the trustee. The specific
reasons for information exchange and coordination
with natural resource trustees are to:
• Assist the site manager in determining the tech-
nical adequacy of ecological investigations,
• Assist the trustee in evaluating the actual
potential injury to trust resources, and
• Identify remedial alternatives that include ap-
propriate actions to protect and restore natural
resources (and thus minimize the need to re-
cover residual damages).
Although coordination with trustees is a re-
quirement, site managers should also view it as an
opportunity. Operating through the BTAG or di-
rectly with the trustees, the site manager can obtain
expert advice and review of work plans, data, and
reports. This can be invaluable for selecting environ-
mentally protective remedies that allow projects to
proceed on schedule. It is important to emphasize
that ecological studies conducted as part of the RI/FS
are not intended as preliminary work toward a Natu-
ral Resource Damage Assessment. Nonetheless, a
properly designed ecological assessment may go a
long way toward resolving questions that might oth-
erwise require lengthy NRDA-related proceedings
and delay or prevent a comprehensive settlement
with responsible parties.
At a minimum, the site manager should meej
the coordination requirements of CERCLA by solicit-
ing review comments from trustees on:
The draft and final RI/FS work plans,
The draft RI and FS,
The final RI and FS,
The Proposed Plan for remediation,
The draft ROD,
The final ROD, and
The RD/RA.
Trustee involvement is especially valuable at
certain points in the Superfund process, such as the
scoping phase of the RI/FS and the review of the
ROD. The portions of the ROD dealing with site
characterizationandriskassessmentparticularly ben-
efit from trustee input. While EPA considers trustee
input in deciding on remedial action, selection of the
remedy is the sole responsibility of EPA.
It is important that site managers emphasize
to trustees that any comments must be provided
within EPA timeframes to prevent the possibility of
the RPM missing management commitments
delaying remediation. Trustees should also be a wan
that they risk the chance of forfeiting this right to
comment if reviews are not made in a timely manner.
March 1992 • Vol. 1, No. 3
10
ECO Update
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Site managers may also wisn to consult with
trusteesatotherstagesoftheremedial process. Trustee
representatives may be able to provide technical ad-
vice or services on specific issues before the review
step requires a more formal response.
At any stage of the Superfund process where
notifying trustees is advisable, thesite managershould
plan on contacting all trustees who have been notified
at an earlier stage of the remedial process and who
have expressed an interest in reviewing the above
documents. If the trustees are members of the BTAG,
coordination can take place through that organiza-
tion. However, not all trustees are represented on
BTAGs. If other Federal, State, or Indian trustees
have been notified and have indicated that resources
under their trusteeship may be affected, the site man-
ager should provide copies of all relevant documents
to those trustees as well as to those on the BTAG.
Ensuring that coordination requirements have been
met is the responsibility of the site manager, not of
the trustee. The site manager should document all
coordination efforts with the trustees.
Coordination with natural resource trustees
does not mean that EPA must comply with all trustee
representatives' suggestions or recommendations
regarding a site. EPA and the trustees have different,
although complementary, responsibilities with re-
spect to site assessment. The ecological assessment
portion of the RI/FS is intended to determine if
remedial action is necessary and, if so, which reme-
dial action is likely to be most protective of environ-
mental receptors. The ecological assessment need not
be designed to gather data appropriate for a natural
resource damage assessment, even though it may end
up being useful for that purpose. Trustee representa-
tives are generally aware of the differences in the
objectives and data needs between the RI/FS ecologi-
cal assessment and the NRDA.
If there is a question as to the purpose of
studies recommended by natural resource trustees,
the site manager should consult with the BTAG or
other technical support personnel within EPA to de-
termine what information is needed to meet the ob-
jectives of the RI/FS. Wherever possible, the site
manager should seek to obtain a consensus of experts,
including trustee representatives, before proceeding
with any plan to assess ecological effects at a site.
Compliance with ARARs
Many trustees derive their authority from
their agencies' statutory mandates to protect or man-
age the nation's natural resources. As such, trustee
representatives are often well versed in the require-
ments of Federal laws pertaining to their trust re-
sources, which may be AJRARs for a particular site. By
consulting with trustee representatives, a site man-
ager can obtain valuable advice on which laws and
regulations apply to a site. Compliance with such
requirements in the RD/RA may meet some or all of
the trustees' concerns and thus reduce the likelihood
of natural resource damage proceedings.
CERCLA and NCR provide for
prompt notification of, and
coordination with, trustees to
ensu re that remedial actions are
selected that protect and restore
natural resources.
Conclusion
The role of the natural resource trustee is
integral to the CERCLA process of assessing and
remediating uncontrolled hazardous waste sites to
protect human health and the environment. CER-
CLA and the NCP provide for prompt notification of,
and coordination with, trustees to ensure that reme-
dial actions are selected that protect and restore natu-
ral resources. Trustee representatives can provide
valuable advice, comments, and technical support
during the remedial process, to help ensure that
projects remain on schedule and within budget Al-
though trustee and EPA responsibilities differ, coop-
eration and coordination are essential to the eventual
success of the remediation effort.
ECO Update
U
March 1992 • Vol. l,No.3
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EPA
United States
Environmental Protection
Agency
Off ice of
Solid Waste and
Emergency Response
Publication 9345.0-051
May 1992
ECO Update
Office of Emergency and Remedial Response
Hazardous Site Evaluation Division (OS-230)
Intermittent Bulletin
Volume 1, Number 4
Developing A Work Scope For
Ecological Assessments
This Bulletin is intended for Remedial Project
Managers (RPMs), to help them plan and manage
ecological assessments of sites as part of the Remedial
Investigation and Feasibility Study (RI/FS) process.1
As used here, the generic term work scope describes
the process of specifying the work to be done for the
ecological assessment, as part of the overall RI Work
Plan. The term encompasses project scoping, devel-
opment and approval of the Work Plan, and prepara-
tion of the Statement of Work (SOW) for contractors
(at Fund-lead sites).
The outcome of a successfully executed work
scope should be an ecological assessment that in-
cludes four essential components: problem formula-
tion, exposure assessment, ecological effects assess-
ment, and risk characterization.2 A work scope should
also provide for close oversight of individual tasks.
This will ensure that the assessment accomplishes its
objectives within reasonable budget and schedule
limitations.
Need for Clarity, Specificity, and
Completeness
SOWs and Work Plans should dearly state the
studies needed at each phase of the assessment. In addi-
tion, they should include other parameters concerning an
assessment, such as sample collection, data analysis, and
reports. Specifically, SOWs and Work Plans should de-
scribe:
• Which studies should be conducted;
• Why they should be conducted;
• When and where they should be conducted;
• What data should be collected;
• How samples should be collected, handled, and ana-
lyzed;
• How data should be evaluated; and
• What reports should be produced.
IN THIS BULLETIN
The Role Of The Biological Technical Assistance
Group 2
Points To Consider In Developing A Work Scope 2
Elements Of An Ecological Assessment Work Scope ....4
Ensuring Contractor Capability To Do Work 7
Review Of Interim And Final Products 8
Sample Work Scope 9
Conclusion 9
Appendix 11
1 Although the primary focus of this document is on the RI/FS
process, On-Scene Coordinators may find much of the informa-
tion useful in evaluating sites during the removal process.
^Ecological Assessment of Superfund Sites: An Overview (ECO Update
Vol. 1, No. 2).
ECO Update is a Bulletin series on ecological assessment of Superfund sites. These Bulletins serve as supplements to Risk Assess-
ment Guidance for Superfund, Volume II: Environmental Evaluation Manual (EPA/540-1-89/001). The information presented is
intended as guidance to EPA and other government employees. It does not constitute rulemaking by the Agency, and may not be
relied on to create a substantive or procedural right enforceable by any other person. The Government may take action that is at
variance with these Bulletins.
-------
Preparing a clear, specific, and
thorough SOW will avoid such
problems as the following:
• Too much work,
• Too little work,
• Incorrect work, and
• Inadequate QA/QC.
The work scope should also detail how decisions
will be made about the need for additional studies.
Preparing a clear, specific, and thorough SOW will
avoid such problems as the following:
• Too much work. In the absence of clear direction, a
contractor may do considerably more work than is
required to characterize the ecological risks at the
site, wasting both time and money. The studies could
be valid, well-designed, and complete, but unneces-
sary given the nature of the site and its contaminants.
• Too little work. An improperly designed study can
result in inadequate attention to potentially impor-
tant habitats or species associated with the site, too
few sampling stations to characterize a habitat, or too
few data points for meaningful statistical analysis.
Such shortcomings could result in the need to con-
duct additional studies and cause delays in produc-
ing an acceptable RI/FS.
• Incorrect work. If the SOW is not specific enough as
to what work is needed or what the objectives of the
studies are, the contractor may conduct studies that
fail to meet the needs of the RI/FS decision-making
process. In this case, valuable time may be lost as the
correct studies are rescheduled.
• Inadequate QA/QC. If the SOW does not specify
data quality objectives (DQOs), the data may not
meet the level of quality required to make decisions
on risk or remedial actions. As above, a delay in the
RI/FS process may result.
The Role Of The Biological Techni-
cal Assistance Group
MostEPARegionalOfficeshaveestablished groups'
of biologists to advise site managers on ecological assess-
ment in the RI/FS process from the Work Plan stage
onward. These Biological Technical Assistance Groups
(BTAGs)3 provide valuable help in the development of a
work scope.
RPMs should contact the Regional BTAG Coor-
dinator as early in the process as possible, certainly
before the Work Plan has been developed. The RPM
should provide appropriate documentation on the site and
its contaminants to BTAG members before the group meets
to discuss the site. In addition, the BTAG may find a brief
oral presentation on the site and its history helpful at this
time. (A future ECO Update will provide guidance on how
to provide the BTAG with useful information in this initial
briefing.) Following this initial review of site data, the
BTAG can make recommendations on the need for studies
to characterize the ecological risks posed by the site. When
the draft Work Plan has been developed, BTAG review
may elicit further helpful comments.
The BTAG should also be consulted when interim
products (reports, data summaries, etc.) are delivered.
Based on the data in such a product, the BTAG
recommend modifications to the original work
Because this kind of "mid-course correction" can save a
project time and money, the RPM is well advised to sched-
ule time for such reviews in the Work Plan.
Points To Consider In Developing A
Work Scope
Definition of Objectives
The work scope for the ecological assessment of a
Superfund site requires an overall objective to provide the
assessment with direction. When an assessment has a dear
objective, the RPM can readily determine which studies
will further the assessment. For example, at a site where
chemicals from mine tailings contaminated the cold moun-
tain streams that flow through the area, the work scope had
for one of its objectives to determine whether resident fish
had suffered adverse impact. Consequently, the work
scope specified studies that concerned fish and their envi-
ronment. These studies included aquatic toxicity tests, a
'These groups are sometimes known by different names, depending on the Region, and not all Regions have established BTAGs. Read'
should check with the appropriate Superfund manager for the name of the BTAG coordinator or other sources of technical specialized
facilities, and specialized equipment necessary to carry out the work. If not, qualified subcontractors should be sought for those tasks where
their qualifications are needed. ^
May 2992 • Vol. 1, No. 4
ECO Update
-------
fish survey, and bioaccumulation4 studies using resident
fish.
FThe overall assessment objective may be clear
from the outset, based on data from previous studies or on
an evaluation of the concentrations and known effects of
site contaminants. More likely, some preliminary studies,
including a site visit and collection of screening-level data,
will be needed to identify and specify the objective of the
ecological assessment. Where possible, these preliminary
studies should incorporate the need for future work.
Just as an ecological assessment gains direction
from having an overall objective, each study that the work
scope specifies also should have a clear objective, such as
filling a data gap or testing a hypothesis about the effects of
the site's contaminants on resident organisms. By stating
a study's objective, an RPM provides guidance for design-
ing the study. For example, the work scope for the mining
site described above called for aquatic toxiciry testing to
determine whether the water was toxic to freshwater fish
that thrive at low temperatures. This study objective
provided specific direction in planning the toxicity tests.
Assessment Design
The work scope lays out the design for an ecologi-
cal assessment. Assessment designs vary tremendously
from site to site depending on:
• The objective of the assessment;
• The size, location, and accessibility of the site;
• The site's ecology—what is already known and what
needs to be known; and
• The site's contaminant history.
In an ecological assessment, the individual studies
are the pivotal elements. If the overall objective gives an
ecological assessment a purpose, the studies are the ve-
hicles by which it attains its purpose. Studies can include
chemical analyses of media or biota, toxicity testing of
laboratory or resident organisms, biological field studies,
and analyses of organisms' physiological or pathological
condition. However, because a work scope indicates only
those studies necessary for assessing a specific site, any one
assessment need not include all of these types of studies.
The assessment design specifies not only which studies to
perform but also the level of effort for each. For example,
the work scope developed for the mining site described
above included toxiciry testing, but only of one medium
(surface water) and with only one type of test organism
(fathead minnow). At another site, toxicity testing might
include evaluation of soil, sediment, and surface water
using several different organisms.
The complexity of an ecological assessment makes
it essential that trained ecologists have responsibility for its
design. The RPM can consult the BTAG for advice as to
which media to analyze, which studies to perform, and at
what level of effort. The RPM can include this information
in the SOW. As discussed below, since the contractor has
responsibility for developing the Work Plan from the
SOW, the RPM needs to consider whether the contractor's
staff has the required expertise. After a contractor has
prepared the Work Plan, the BTAG can review it and
advise the RPM whether or not to approve it.
The phased approach ensures
that:
• Only the necessary work will
be done, and
• All the necessary work will be
done.
Phased Approach to Task Implementation
For most sites, a phased approach with expert
review at each phase results in the most efficient use of
resources. With the phased approach, data or observations
from one phase determine whether further studies are
needed to meet the assessment's objectives and, if so, what
these studies are. At some sites, the phased approach
might result in a low level of effort adequately characteriz-
ing ecological risks. At others, the phased approach might
indicate that the assessment should be expanded to in-
clude studies of specific habitats or contaminants in order
to evaluate the risks. At still other sites, the phased ap-
proach could identify areas originally not considered at
4 Bioaccumulation is the accumulation of a substance in an organism's tissues as a result of respiration, absorption, or feeding.
ECO Update
May 1992 • Vol. I, No. 4
-------
risk. In this case, the RPM would want to expand the work
scope to include an assessment of the newly identified
area. Review of interim products, such as a report on the
levels of contaminants of concern or a field survey of
resident species, can contribute to the phased approach.
Careful review of interim products can help to ensure that
the assessment remains focused on those studies most
important for evaluating the site's ecological effects.
To summarize, the phased approach ensures that:
• Only the necessary work will be done, and
• All the necessary work will be done.
The value of the phased approach can sometimes
be outweighed by other factors. For example, seasonality
affects when certain types of studies, such as floristics
surveys, can occur. In some cases, budgetary restrictions
and time constraints may be incompatible with the phased
approach. RPMs may need to consider such factors when
planning studies.
In practical terms, the phased approach requires
an RPM to decide when a contractor should proceed from
one task to the next and whether the contractor should
proceed with one alternative task or another. In making
these determinations, the RPM interprets information from
completed studies. The BTAG can assist the RPM in
identifying criteria appropriate for evaluating data. (See
Figure 1.)
An ecological assessment
should be designed to contribute
to remedial decisions at the site.
As an example of the phased approach, consider
the following hypothetical case. (See Figure 1.) An RPM
has a field reconnaissance done in order to identify and
map potentially exposed habitats at a site. The RPM then
uses the results of this study to decide on the numbers and
placement of sampling stations for initial chemistry data.
After the first round of sampling for contaminant levels at
these stations, the chemistry data indicate that contaminant
levels are high enough in some areas of the site to warrant
collection of biological data from the field, along with
additional data on site chemistry. The field data collected
indicate the advisability of toxiciry testing at certain stations,
but not at others. In other parts of the site, the low level of
contaminants indicate that no further biological
investigation is required. Thus, in this hypothetical
example, use of the phased approach results in the areas^
most in need of study receiving the most attention.
An ecological assessment
involves problem formulation,
exposure assessment, eco-
logical effects assessment, and
risk characterization.
Relating Ecological Information to
Remedial Decision-Making
While an ecological assessment of a Superfund site
might extend our knowledge of the environment and the
effects of contaminants on it, the assessment is not in-
tended as a research project. Rather, it should be designed
to contribute to remedial decisions at the site. Ecological
assessments serve this function when they determine
whether remediation is needed, indicate the conditions (if
any exist) requiring remediation, suggest technologies f or
achieving remediation, and/or estimate the environmen-
tal effects of proposed remedial alternatives. At the earliest
stages of Work Plan development, the RPM and BTAG
should consider what types of ecological information will
contribute to remedial decisions. For example, the site
manager may need to know:
• If remediation goals are protective of environmental
receptors,5
• If ecological risk considerations will affect the defini-
tion of the area to be remediated,
• If special measures need to be taken during
remediation to protect natural habitats, and
• What monitoring will be needed to ensure protection
of environmental receptors during and after
remediation and to evaluate the effectiveness of re-
medial actions.
'Receptors are individuals, populations, or communities/
habitats that may be exposed to a contaminant.
May 1992 • Vol. 1, No. 4
ECO Update
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Field survey identifies locations A-L as potentially exposed habitats requiring additional chemical analysis
Level of contaminants high enough only at locations E-L to
warrant collection of additional field and chemical data.
Results of additional field
and chemical studies
indicate advisibility of
toxicity testing at locations
I, J, K, and L
Figure 1. The Phased Approach
As this hypothetical ecological assessment
illustrates, the phased approach results in the
areas most in need of study receiving the
most attention.
Questions such as these should form part of the
initial scoping session, where the RPM and the BTAG
select appropriate studies and study designs.
Elements Of An Ecological Assessment
Work Scope
As described in Ecological Assessment of Superfund
Sites: An Overview (ECO Update Vol. 1, No. 2) an ecological
assessment involves problem formulation, exposure as-
sessment, ecological effects assessment, and risk character-
ization. To ensure that an assessment fulfills its objectives,
the work scope should use its elements to accomplish these
tasks. In addition, the work scope should identify data
quality indicators to ensure that established DQOs are met.
Problem Formulation
Problem formulation defines the assessment's ob-
jectives and also involves a thorough description of the
site. This qualitative description must occur before decid-
ing on any substantial quantitative work.
An initial site description should include citations
from existing site literature (such as the Preliminary As-
sessment, Site Inspection, or any studies conducted in
support of removal actions) relating to site history, physi-
cal features of the site, known or suspected contaminants,
habitats on or near the site, species expected at or near the
site, and known or anticipated effects of site contaminants
on receptors. Investigators should determine whether
threatened or endangered species are known or suspected
to occur at or near the site. Descriptions of potentially
affected habitats should include as much detail as possible.
For instance, stream habitats vary considerably depending
on stream depth and width, type of stream bottom, and
types of vegetation in and adjacent to the stream. Informa-
tion pertaining to these types of characteristics could affect
both the kinds of studies required to evaluate possible
effects and the level of effort needed to conduct the studies.
This qualitative description of the site helps to
indicate whether further studies are needed and, if they
are, what these studies should be. For example, if scientific
ECO Update
May 2992 • Vol. 1, No. 4
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literature or databases indicate that a site's contaminant
concentrations consistently fall below levels likely to cause
adverse ecological effects, additional analyses may be un-
necessary. On the other hand, if contaminant concentra-
tions suggest a need for further investigation, the initial site
description may identify potential exposure routes useful
in targeting the additional studies to media and areas of
greatest concern. Targeting studies makes the most effi-
cient use of the time and money available for the ecological
assessment.
A site visit should form part of the initial site
description phase. In addition, the RPM may decide to
characterize the site's ecology further by conducting lim-
ited field studies. These studies could include aerial pho-
tography, evaluation of habitats' suitability for wildlife,
functional evaluation of wetlands,6 qualitative or semi-
quantitative examination of the environment for evidence
of stress (e.g., stressed or dead vegetation, bare soil and
erosion, dominance by pollution-tolerant species), and
field verification of the presence or absence of key species.
At some sites, the existence of site descriptions made prior
to contamination may enable the RPM to assemble a "be-
fore and after" picture of the site.
Based on the information developed in this initial
site description, the investigator (under the direction of the
RPM and with BTAG consultation) should specify:
• The receptors (habitats and species) most likely to be
exposed to site contaminants,
• The contaminants most likely to be of ecological
concern,
• The ecological effects most likely to be important
with regard to the site, and
• The studies needed to characterize actual or potential
adverse effects associated with site contaminants
and, where applicable, the hypothesis that the study
will test.
Exposure Assessment
Since exposure assessment quantifies the actual or
potential exposure of receptors to contaminants, the work
scope must plan for studies that gather appropriate data on
both receptors and contaminants. Evaluation of chemical
and biological data will indicate which receptors and
contaminants are appropriate subjects of study and how
best to evaluate exposure at a particular site. And, as in all
other decisions of this type, the RPM can consult the BTAG
before committing resources.
The work scope can either specify receptors for
exposure studies or set criteria for selecting receptors.
Receptors studied in the exposure assessment could be
chosen from among the site's biota, or surrogate species
(e.g., standard test species) might be used. Resident spe-
cies used as receptors can be selected from among those
most likely to suffer adverse effects from site contaminants
or those considered representative of or critical to the
ecosystem. Alternatively, the work scope could specify
receptors for further study because they are of concern for
statutory or other reasons (e.g., those species protected
under Federal law). When the RPM has satisfied these
criteria for choosing receptors, he or she can then consider
which of the species are most amenable to rapid and
inexpensive field evaluation. Field, laboratory, and litera-
ture studies conducted in the Problem Formulation phase
can also aid in selecting and characterizing receptors. The
exposure assessment should include information on feed-
ing habits, life history, and habitat preferences of receptors.
To study exposure to contaminants, the work scope
might include additional chemical analyses and the mea-
surement or estimation of exposure point concentrations.
Chemical analysis of plant and animal tissues is one useful
technique for determining whether exposure to contami-
nants has taken place. For contaminants known to
bioaccumulate, analysis of tissues from organisms repre-
senting different trophic levels (e.g., plant, herbivore, car-
nivore) also permits measurement of dietary exposure for
species that feed on contaminated qrganisms. Biochemi-
cal, physiological, and histological studies can also pro-
vide information about exposure of receptors to site con-
taminants.
The work scope could also specify studying expo-
sure by means of fate-and-transport models. Fate con-
cerns the ultimate chemical disposition of a contaminant,
such as remaining stable, undergoing photodegradation,
or combining with another substance. Transport, or mi-
gration, refers to the movement of a contaminant from one
medium to another, from one location to another within
the same medium, or into biota. Site characteristics, con-
taminants' physical and chemical properties, and
* A functional evaluation of a wetland determines the importance of the wetland for such values as wildlife habitat, pollution abatement,
studies are appropriate, if at all, and when they should be conducted.
May 1992 • Vol. 1, No. 4
ECO Update
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bioaccumulation studies provide information useful in
predicting the fate and transport of site contaminants.
Ecological Effects Assessment
Ecological effects assessment links concentrations
of contaminants to adverse effects in receptors. Literature
reviews, field studies, and laboratory studies provide the
information for making this link. However, the ecological
assessment of a site may not require all three of these types
of studies.
Field studies of populations and communities7
support ecological effects assessment by providing infor-
mation on the condition of populations of resident species
and on any contaminant-related changes in ecological
communities. In their focus on resident populations, field
studies play a central role in identifying receptors. Such
studies also can allow investigators to collect samples for
laboratory analysis.
Field studies focus on natural environments, in-
cluding freshwater, marine, or terrestrial environments.
Aquatic field studies can include surveys of benthic (bot-
tom-dwelling) organisms and surveys of organisms in the
water column. Marine studies can also include surveys of
coastal and tidal areas. In terrestrial environments, field
studies may focus on vertebrates, invertebrates, or vegeta-
tion. An RPM also may need to conduct field studies in
such human-managed environments as residential neigh-
borhoods and other landscaped areas, since some wildlife
species make use of these areas for all or part of their life
cycle.
Generally, habitats that are potentially or actually
exposed to contaminants require some field study. Con-
sulting with the BTAG will enable the RPM to select the
methods and level of effort appropriate to the site and its
remedial objective. Whenever possible, the work scope
should specify standard or commonly accepted field meth-
ods. A future ECO Update will provide information about
field studies useful at Superfund sites.
Level of effort depends on the choice of qualita-
tive, semi-quantitative, or quantitative studies. In some
cases, qualitative studies will adequately describe the habi-
tats and species at risk. However, most sites with sus-
pected adverse effects will require some semi-quantitative
or quantitative studies. For example, at one site a semi-
quantitative approach for evaluating effects of stream pol-
lution might sufficiently characterize differences in species
composition between contaminated and uncontaminated
areas of a stream. But another site might require a more
detailed quantitative analysis to discern such differences.
An important task in preparing a work scope
involves coordinating different types of studies. In an
ecological effects assessment, simultaneous collection of
site chemistry data and biological field data allows the
analysis to show clearly whether a correlation exists be-
tween contaminant presence and ecological effects.
Toxicity tests (bioassays) constitute a major type of
study used in assessing ecological effects at Superfund
sites. Toxicity tests expose selected organisms to water,
soil, or sediment from the site to determine whether the
medium adversely affects the organisms. Most commonly,
technicians perform these tests in laboratories using stan-
dard test organisms. However, toxicity tests also can occur
on-site and can use resident organisms.
Especially for a site with only one or a few con-
taminants, toxicity tests can contribute to the weight of
evidence linking the contaminants to biological effects.
Specifically, while chemical analyses indicate the presence
of contaminants, they do not indicate whether contami-
nants are bioavailable.8 In order to have a toxic effect, a
contaminant must be both bioavailable and toxic. The
relationship between toxicity and site contaminants is less
easily interpreted for sites with a more complicated con-
taminant picture.
The work scope should coordinate the collection
of site chemistry data and toxicity data. When the work
scope specifies that toxicity tests will occur in the labora-
tory, field scientists should collect samples for chemical
analyses and toxicity tests at the same time and in the same
place. When the work scope calls for in situ toxicity tests,
chemical sampling should happen concurrently and at the
same locations. In this way, analysis of the data can most
clearly evaluate correlations between toxicity results and
contaminant levels.
Consulting closely with the BTAG can help the
RPM decide which tests are appropriate and the specific
conditions under which to conduct the tests. A future ECO
Update will focus on using toxicity tests in ecological as-
sessments.
Risk Characterization
In ecological assessments, risk characterization
evaluates the evidence linking site contaminants with ad-
verse ecological effects. To characterize risk, the investiga-
7 A population is a group of organisms belonging to the same species and inhabiting a contiguous area. A community consists of populations
of different species living together.
' Bioavailabihty is the presence of a substance in a form that organisms can take up.
ECO Update
May 1992 • Vol. 1, No. 4
-------
tor evaluates all of the chemical and biological data relating
to the site, comparing the results of the exposure assess-
ment with the results of the ecological effects assessment.
In particular, fate and transport studies can provide evi-
dence of links between site contaminants and observed or
predicted effects.
Also relevant to risk characterization are the re-
sults of the chemical analyses of media, toxicity testing,
and field studies. At some sites RPMs will have had these
studies conducted along contaminant gradients. Where
risk characterization establishes a link between contami-
nants and adverse effects, it should also describe the quali-
tative or quantitative ecological significance of these ef-
fects.
A successful work scope is one that correctly an-
ticipates the types of studies that will provide the data
needed for risk characterization.
The results of an ecological
assessment support the re-
medial decision-making process
only if the data are scientifically
defensible.
Quality Assurance
The results of an ecological assessment support
the remedial decision-making process only if the data are
scientifically defensible. Usually, this means that the data
should be (1) accurate and (2) amenable to statistical analy-
ses (for quantitative studies). Data quality objectives are
qualitative and quantitative statements of the overall level
of uncertainty that a decision maker is willing to accept.
Consequently, data quality objectives reflect the statistical
design of the study and the level of significance needed to
support any conclusion that might be drawn from the
study. For example, the SOW should specify a sample size
large enough to account for natural variability to ensure
that DQOs are met. In reviewing the Work Plan, the RPM
should ensure that minimum sample sizes are specified for
statistically valid analyses, that significance criteria meet
the needs for remedial decision making, and that quality
control procedures are in place to ensure accuracy and
precision.
Before approving a Work Plan,
the RPM should make certain that
the contractor has the trained
personnel, specialized facilities,
and specialized equipment ne-
cessary to carry out the work. If
not, qualified subcontractors
should be soughtf or those tasks
where their qualifications are
needed.
Quality assurance is the set of procedures that
ensure that the quality of data meets the needs of the user.
The Work Plan establishes quality assurance for field work
and laboratory analyses by specifying criteria for such
items as sample collection, sample handling, and numbers
of replicate analyses. Selecting standard methods speci-
fied in EPA or other Federal agency manuals (subject to
EPA approval), when these methods are appropriate, can
provide confidence of a stated level of quality assurance
because they have built-in quality control activities.
Laboratories that conduct standard toxicity tests,
such as those required under the National Pollutant Dis-
charge Elimination System (NPDES), have in place quality
control procedures that are readily subject to review and
audit. Contractors experienced in conducting field studies
should also have standard procedures for ensuring accu-
racy and reproducibility in their work. As an example of
quality control in a field study, a survey of benthic inver-
tebrates could require an independent taxonomist to clas-
sify a randomly selected sub-set of the organisms identi-
fied by the study's field or laboratory staff.
When the work scope specifies clear and appropri-
ate quality assurance procedures, the data collected should
satisfy the specified data quality indicators of precision,
accuracy, representativeness, completeness, and compa-
rability.
Ensuring Contractor Capability To Do
Work
Ecological studies require trained personnel, and
some studies also require specialized facilities and equip-
ment. Before approving a Work Plan, the RPM should be
May 1992 • Vol. 1, No. 4
ECO Update
-------
satisfied that the contractor proposing to carry out the
work can do so. If not, qualified subcontractors should .be
sought for those tasks where their qualifications are needed.
Personnel
In selecting a contractor, an RPM must look for a
direct match between contractor qualifications and the
scope of work. To this end, the RPM should request
information on the specific training and experience of
proposed individuals with respect to the specific tasks to
be undertaken. For example, if a Work Plan calls for
sampling benthic invertebrates in a stream, those conduct-
ing the study should:
• Be familiar with the types of equipment (e.g., Surber
sampler, artificial substrates) appropriate to the study
site;
• Know how and where to collect samples (e.g., what
kinds of stream bottoms support which species);
• Know what kinds of environmental data to collect
along with the biological and chemical samples (e.g.,
water temperature, pH, dissolved oxygen, hardness);
and
• Have the requisite taxonomic expertise to identify
the organisms (principally the larval stages of in-
sects) collected.
On the other hand, these same individuals may
lack qualifications for conducting other types of studies,
such as wetland assessments or the collection of small
mammals for tissue analysis. Although some experienced
biologists have developed considerable expertise working
in a wide variety of habitats and with a broad range of
species, many others are specialists in their fields and do
not know the details of conducting studies outside their
specialty. Consequently, the RPM must ask for evidence of
specific individuals' capabilities to carry out proposed
tasks. This evidence can consist of results of similar studies
conducted in the past. These results should demonstrate
that the contractor performed studies correctly and that the
resulting data served its intended purpose.
Facilities and Equipment
The RPM also should require a contractor to dem-
onstrate capability in terms of any specialized f atilities and
equipment needed to conduct the studies selected for a
particular site. For example, most of the toxicity tests used
to evaluate aquatic systems are standard procedures de-
veloped for NPDES. Many States have certification pro-
grams for laboratories that conduct NPDES toxicity tests.
If the work scope calls for such tests at a site, the RPM can
ask that the contractor use a laboratory certified in at least
one State (if possible, the State where the site is located),
and that the laboratory show proof that it has conducted
the same or similar tests in the recent past. Alternatively,
where a State and its neighboring States have no certifica-
tion program, the RPM can obtain the name of an appropri-
ate laboratory from the State agency charged with regulat-
ing NPDES permittees. In the case of field sampling, the
BTAGor Regional field biologists can evaluateacontractor's
capabilities.
In all cases, contractors must possess both the
appropriate equipment and staff trained 'on that equip-
ment. For instance, a commonly used method for collect-
ing fish involves electroshock equipment that stun the fish,
causing them to float to the surface. Electroshock equip-
ment ranges in size from small backpack units to large
boat-mounted units. For both safety and efficacy, it is
essential to use the right size of equipment manned by a
crew familiar with its operation and safety requirements.
Review Of interim And Final Products
In keeping with the suggested phased approach,
the RPM should plan for BT AG review of interim products
such as initial site descriptions, initial field surveys, and
reports on specific studies such as toxicity test results or
field data. Such reviews form the basis for revising the
work scope to account for the new findings.
In addition to the interim products mentioned
above, the RPM should have the BTAG review the draft
Work Plan and the draft ecological assessment before the
contractor proceeds with the final version. With regard to
the draft ecological assessment, the RPM should particu-
larly request the BTAG to comment on the quality of
studies and the validity of their findings. The RPM will
also want to know whether the data support any conclu-
sions about proposed remedial actions at the site.
Sample Work Scope
The Appendix presents an example of the kinds of
components likely to occur in a typical work scope. Of
course, work scopes designed for particular sites will differ
significantly from the general one in the Appendix. An
RPM will find it necessary to tailor the work scope to the
specific conditions and objectives at an individual site.
ECO Update
May 1992 • Vol. 1, No. 4
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The example in the Appendix also demonstrates
how BTAG review of interim products can alter the scope
and level of effort for succeeding tasks. The example
always states that products are subject to review and
approval by the site manager, because the BTAG has no
ofncialauthoritytoapproveordisapprovecontractorwork.
Nevertheless, wherever appropriate, the RPM should ask
the BTAG for review and advice on each product. In
scheduling a project, RPMs need to allow time for the
review process. In fact, some Regional BTAGs require a
minimum review period.
In addition to the general work scope in the Ap-
pendix, RPMs in several Regions have available to them
generic work statements or other guidance material pre-
pared by their BTAGs. RPMs should check with the BTAG
coordinator in their Region to obtain any such guidance.
Conclusion
This Bulletin has summarized the issues an RPM
needs to address in developing work scopes for the eco-
logical assessment of Superfund sites. Because every site
presents a unique combination of study problems, RPMs
should consider the expert advice of BTAG members as an
essential part of the planning process for these assess-
ments. These specialists should be consulted as early as
possible in the planning stages for a site, and should
remain involved in the planning and oversight throughout
the life of the project. By involving the BTAG in this way,
the RPM can be assured that ecological as well as human
health effects will receive the full attention called for in the
law and in Agency policy directives.
Figure 2 Ordering Tasks in an Ecological Assessment
An investigator can conduct simultaneously some of the taste that a Work Plan details for an
ecological assessment. As indicated below, which tasks can occur simultaneously will vary somewhat
with the site. Note that Site 2 does not require Task 6 (Final Data Collection), indicating that Task 5
gathered all the data necessary for an ecological assessment
S/reT
Site 2
9
E
Task 2
Site Reconnaissance Visit
Tasks
Data Collection
TaskB
Final Data Collection
Task?
Risk Characterization
Task 8
Report Preparation
Task
Site Des
Task
Site Sere
Task?
Risk Charade
r
sription Site Reo
I
3 Tat
*ning Draft of \
I
Tasks
Data Collection
1
Ta
rization Report 1
I
Task 9
Report Revision
Task 2
onnaissance Visit
Sk4
rVorkPlan
sk8
'reparation
May 1992 • Vol. I, No. 4
ECO Update
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APPENDIX
SUGGESTED TASKS IN PLANNING AND EXECUTING
AN ECOLOGICAL ASSESSMENT
The following tasks can help a contractor in assembling an acceptably detailed and focused ecological assessment.
Wherever possible, these tasks should be coordinated with the human health assessment and any hydrogeologic investiga-
tions.
A site's ecological assessment may not require all of the tasks. For example, with site description (Task 1) and the
reconnaissance visit (Task 2) complete, the RPM may decide that the Work Plan can be drafted (Task 4) without any further
site characterization (Task 3).
Note also that an investigator can conduct certain tasks simultaneously rather than sequentially, greatly enhancing
the efficiency of the process (Figure 2). Precisely which tasks can occur simultaneously and which the investigator must
conduct sequentially depend upon the site.
Task 1. Site Description
Purpose: Preliminary screening of the extent of contamination and the potential for adverse effects
Description: Qualitatively describe site based on existing data from the Preliminary Assessment, Site Inspection, and
other sources, including:
1. Physical description of the site and its surroundings, including photos and detailed maps
2. Nature and extent of contamination by medium and contaminant type
3. Site-associated habitats potentially exposed to contaminants
4. Initial toxicity assessment of site contaminants with respect to environmental receptors, including
comparison to criteria and other benchmarks
Submit interim report to site manager for review.
Task 2. Site Reconnaissance Visit
Purpose: Gather first-hand expert opinion of site's condition and suggestions about what, if any, studies are needed
Description: If authorized by site manager, prepare plan for site reconnaissance, including:
1. Chemical and biological data needed for more complete initial site description '
2. Methods to be used to collect necessary data
3. Criteria for deciding whether and what future studies might be necessary
Submit reconnaissance plan to site manager for review.
TaskS. Site Screening
Purpose: With limited studies, identify and characterize habitats and characterize exposure and ecological effects.
[For some sites, information will suffice for risk characterization]
ECO Update 11 May 1992 • Vol. 1, No. 4
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Description: If authorized by site manager, further characterize sue based on field observations, including, as
appropriate:
1. More detailed habitat identification and evaluation
a. Suitability for wildlife, including an endangered species consultation with State and Federal agencies
b. Ecosystem value and function (e.g., wetland functional analysis)
2. Qualitative and semi-quantitative surveys of flora and fauna
3. Toxicity tests
4. Additional chemical sampling
5. Identification of appropriate reference sites for comparison to each potentially exposed habitat
6. Simple modeling of transport and exposure
Submit interim report to site manager for review.
Task 4. Draft of Work Plan
Purpose: Develop a plan that will provide any additional information about exposure and ecological effects that is
needed to characterize risk
Description: Draft detailed Work Plan for any further site investigations needed, including overall assessment objective
and, as appropriate:
1. Qualitative, semi-quantitative, and quantitative surveys of flora and fauna in potentially
exposed habitats and reference sites
2. Chemical sampling of media and biota in potentially exposed habitats and reference sites
3. Laboratory and in situ toxicity testing
4. Tissue analyses, enzyme studies, and bioaccumulation studies
5. Simple modeling of fate and transport
For each proposed study above, provide:
a. Objectives of the study, effects to be measured, and relevance to overall risk assessment objectives at
the site
b. Proposed field or laboratory methods and their risk-based detection limits (where appropriate), with
appropriate references to Agency guidelines or other source
c. Criteria for determining sampling locations, expected sampling locations (including detailed maps),
sampling dates, and sample sizes
d. Benchmark, or background values, where appropriate
e. Statistical methods to be used and data quality indicators to meet statistical significance criteria
f. Quality assurance procedures and quality control techniques.
Submit Work Plan to site manager for review and approval. Revise per site manager's direction.
May 1992 • Vol. 1, No. 4 12 ECO Update
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Task 5. Data Collection
Purpose: Gather necessary data regarding exposure and ecological effects
Description: Conduct those studies approved by site manager for immediate execution. Submit interim reports to site
manager for review.
Task 6. Final Data Collection
Purpose: Based on findings of studies conducted, identify and collect any final data needed to assess exposure and
ecological effects
Description: Revise Work Plan per site manager's direction. Conduct next phase of studies as approved by site
manager. Submit interim reports to site manager for review. Repeat this step as needed. Task 6 is an
iterative process that will lengthen or shorten, depending on the results of studies.
Task 7. Risk Characterization
Purpose: Validate the data and their interpretation, and characterize risk.
Description: Prepare the following for review by site manager:
1. Summary of biological and chemical data
2. Detailed outline of ecological assessment
Task 8. Report Preparation
Purpose: Prepare data for presentation.
Description: Prepare draft ecological assessment.
NOTE: Depending on the scope and level of effort decided on by the site manager, not all of the elements listed
below may appear in a given assessment. For instance, not all sites will require toxiciry testing or the full
array of quantitative field studies. The following outline should be modified to account for the studies
actually undertaken at the site with the approval of the site manager.
1. Initial site description and potential receptors (include detailed maps wherever appropriate)
a. Physical description of the site
b. Nature and extent of contamination by medium and contaminant type
c. Potentially exposed habitats
(i) Surface water habitats
(ii) Wetlands
(iii) Terrestrial habitats
(iv) Sensitive or critical habitats
d. Potentially exposed species
(i) Vegetation
ECO Update
May 1992 • Vol. 1, No. 4
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(ii) Invertebrates
(iii) Vertebrates
(iv) Special concern species
2. Selection of contaminants, species, and ecological effects of concern
a. Contaminants of concern and rationale for selection
b. Species of concern and rationale for selection
c. Ecological effects of concern, acceptable and unacceptable levels of effects, temporal and spatial scales
of concern, and rationale for selection
3. Exposure assessment
a. Sources and exposure pathways of contaminants of concern
b. Fate and transport analysis
c. Exposure scenarios
d. Estimated exposure point concentrations by habitat, species, and exposure scenario
e. Uncertainty analysis
4. Ecological effects assessment
a. Known effects of contaminants of concern (from literature)
b. Site-specific toxicity tests—laboratory and in situ
c. Existing toxicity-based criteria and standards
d. Uncertainty analysis
5. Risk Characterization
a. Observed adverse effects in potentially exposed habitats compared to reference sites
(i) Mortality and morbidity
(ii) Vegetation stress
(iii) Habitat degradation
(iv) Presence or absence of key species
(v) Population assessment of key species
(vi) Community indices
(vii) Ecosystem function, such as decomposition or nutrient recycling
b. Analysis of contaminant concentrations in relation to observed adverse effects
c. Analysis of bioaccumulation studies
d. Analysis of toxicity test results in relation to observed adverse effects
May 1992 • Vol. 1, No. 4 ' 14 ECO Update
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e. Comparison of estimated exposure point concentrations with criteria and standards
f. Comparison of estimated exposure point concentrations with toxicitydataand/ortoxicity values from
literature, as appropriate
g. Likely ecological risks associated with present and future land use scenarios
h. Ecologically relevant ARARs
i. Ecological considerations in selecting remedial alternatives (including no action)
j. Uncertainty analysis
Submit draft ecological assessment to site manager for review.
Task9. Report Revision
Purpose: Prepare final presentation of ecological assessment
Description: Revise draft ecological assessment per site manager's review comments and submit final ecological
assessment for inclusion in Rl/FS.
ECO Update 15 Mov 2992 • Vol. I, No. 4
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&EPA
United States
Environmental Protection
Agency
Office of
Solid Waste and
Emergency Response
Publication 9345.0-051
.August 1992
ECO Update
Office of Emergency and Remedial Response
Hazardous Site Evaluation Division (OS-230)
Intermittent Bulletin
Volume 1, Number 5
Briefing the BTAG: Initial Description of
Setting, History, and Ecology of a Site
For many Superfund sites, contaminants can cause
ecological harm as well as posing risks to human health. Part
of the responsibility that a Remedial Project Manager (RPM)
must carry out during the site remediation process is to
assess whether ecological harm has occurred or may occur.
Many Regions have B iological Technical Assistance Groups
(BTAGs) to assist RPMs in managing such assessments.1
This Bulletin focuses on the first opportunity that an
RPM has for conferring with the BTAG about possible
ecological effects at a site. This meeting usually occurs early
in the planning stages of the Remedial Investigation (RI). At
this stage in the Superfund process, the RPM will have the
contractor review whatever information is readily available
about the site's setting, history, contaminants, and ecologi-
cal characteristics. The RPM then makes this information
available to the BTAG as a site description. This group's
input assists the RPM in providing the contractor with clear
direction for planning a well-focused investigation: that is,
one that has clear-cut objectives and that makes the most
efficient use of limited resources.2 The RPM should find
that expert input at this early stage results in long-term
savings in both the time and effort needed to evaluate a site's
ecological condition.
Although the initial meeting with the BTAG has the
same purpose and scope throughout EPA Regions, the
details of such amee ting can vary considerably from Region
to Region. When preparing the site description for this
meeting, the RPM should contact the Region's BTAG
coordinator to learn how the Region handles these briefings.
IN THIS BULLETIN
Objective of Initial Site Description 2
Sources of Information about the Site 2
Information in the Site Briefing 2
BTAG's Preview 5
The Meeting 5
BTAG's Recommendations 5
Meeting Follow-Up 5
Appendix A: Check Sheet 7
1 These groups are sometimes known by different names,
depending on the Region, and not all Regions have established
BTAGs. Readers should check with the appropriate Superfund
manager for the name of the BTAG coordinator or other sources of
technical assistance in their Region. A more complete description
of BTAG structure and function is available in "The Role of
BTAGs in Ecological Assessment" (ECO Update Vol. 1, No. 1).
: "Developing a Work Scope for Ecological Assessments"
(ECO Update Vol. 1, No. 4) discusses the process of planning and
designing ecological assessments.
ECO Update is a Bulletin senes on ecological assessment of Superfund sites. These Bulletins serve as supplements to Risk Assessment Guidance
for Superfund, Volume II: Environmental Evaluation Manual (EPA/540-1 -89/001). The information presented is intended as guidance to EPA and
other government employees. It does not constitute rulemaking by tlie Agency, and may not be relied on to create a substantive or procedural right
enforceable by any other person. The Government may take action that ii Jt variance with these Bulletins.
"I.- Printed on Recycled Pacer
-------
The Objective of the Initial Site
Description: Assessing Whether
More Ecological Information is
Needed
The initial site description begins the process of evaluating
whether a site's contaminants have caused or could later cause
adverse ecological effects. By reviewing readily available infor-
mation about the site's setting, history, contaminants, and ecologi-
cal characteristics, the BTAG can assess whether the site requires
further investigation. Although little site-specific data may exist at
this stage of the RI, providing the BTAG with this information will
assist in evaluating the site.
What types of recommendations can an RPM expect to hear
after presenting the site to the BTAG? For some sites, the BTAG
may decide that no significant ecological impact has occurred or
is likely to occur and that consequently the site requires no further
ecological investigation. In other cases, the BTAG may advise the
RPM to pursue further ecological studies. In these instances, the
BTAG will be able to suggest
• What information is lacking,
• Which studies will elicit this information, and
• What level of effort is appropriate to obtaining the
information.
Sources of Information
about the Site
The investigator3 bases the site description for the initial
briefing on information about the site and its surroundings. Studies
and reports already in the site's record contain useful information.
For example, both the Preliminary Assessment (PA) and the Site
Inspection (SI) can provide a description of the site's geographical
setting, known or suspected contaminants, and general informa-
tion about the surrounding area.
The investigator may also find that State agencies or local
groups have useful information about the site. For example, if the
site contains a fishing stream, the State fish and game agency may
routinely monitor fish species. University researchers may have
conducted biological surveys at or near the site. Environmental
impact statements concerning nearby faculties or projects may
have additional data on natural resources in the area. Historical
societies, fish and game clubs, local or State chapters of such
organizations as the Audubon Society or Nature Conservancy, and
3 The term "investigator" refers to the individual charged with
responsibility for designing and/or carrying out any pan of an
ecological assessment Investigators can include government sci-
entists, contractors, or university scientists. However, the RPM
retains ultimate responsibility for the quality of the ecological
assessment.
local experts, such as foresters, soil conservation specialists, and
naturalists, also may have information relevant to a site descrip-
tion. In particular, such groups may have lists of habitats ai
species found in the area.
In some Regions, field reconnaissance trips occur even at this
early stage, with the RPM, me contractor, and a BTAG member
visiting the site. Observing and studying the site enables the BTAG
member to carry back to the group an expert's first-hand observa-
tions. Such observations are especially helpful at this point in the
Superfund process when few, if any, ecological studies have
occurred. For example, a BTAG member may identify dense
growth of a species associated with polluted sites or, alternatively.
may note the absence of expected species.
RPMs need to be aware that Regions vary in their policies
concerning field reconnaissance visits. Consequently, an RPM
who wishes to have a BTAG member present on such a visit needs
to consult the BTAG coordinator to find out whether and when this
can take place.
The Information
in the Site Briefing
The information contained in a site briefing varies with the
nature of the site and its contaminants, the sources of information
available about the site, and the evaluations already performed
there. However, an RPM should keep in mind that the more the
BTAG learns about a site, the more specific direction it can offer .|
The Appendix at the end of this Bulletin provides a check sheet that!
RPMs may wish to use to make certain that the site description is
as detailed as possible, given the information that is readily
available to the contractor at this early stage. In most cases, the site
description will lack some of the information listed in the Appen-
dix. Such gaps can prove helpful in pointing to issues that may
require further investigation.
The Setting
A site's setting includes its geographical location (including
coordinates) and its surroundings. The setting should include the
site's town, county, and State and should describe the land use of
the area around it. Land use upstream and downstream of the site
also constitutes important information about the setting. Land uses
may include industrial, business, residential, military, agricultural,
recreational, and undeveloped. The setting should note especially
such natural areas as parks, refuges, wetlands, and coastal zones.
The BTAG will also find helpful a description of the general
topography of the area associated with the site. Consequently, the
site description should include such information as whether the site
is wooded or open, flat or hilly, marshy or dry. The setting should
describe surface water associated with the site, along with such
related information as the water body's location, size, depth.
flow rate, where applicable. A description of the aquifer,
overlying strata, and the ground water discharge area is also
imporuint to the site's description. The site's elevation, its size, and
its accessibility may prove useful to know. Investigators can find
August 1992' Vol. I, No. 5
ECO
-------
some of this information in the topographical maps published by
the U.S. Geological Survey and in the National Wetlands Inven-
tory maps. Geographical Information Systems available in the
(Regions may also provide additional information on natural re-
sources in the vicinity of the site. While the setting generally
contains several pieces of information, this description need not be
lengthy.
To appreciate the relevance of this information, consider the
following hypothetical examples:
An abandoned mine. One Superfund site consisted of land
containing a former nickel mine and the area that it had contami-
nated. The RPM' s description of the site's setting indicated that the
site occupied a steep mountain slope, which received heavy snow
cover in winter. Contaminants from the mine had leached into
streams that drained the area. These streams in turn emptied into
a larger stream, which local anglers fished for brook trout before
it flowed into a National Park. This description of the setting
alerted the BTAG to several important facts about the site:
• Because of the slope's steepness, at least pan of the site was
not easily accessible, making it difficult and possibly costly
to assess the ecological condition of these parts of the site.
• Both heavy rains and the annual spring melt resulted in
continuing migration of contaminants into streams draining
the site.
• The presence of a National Park downstream from the site
indicated that site contamination had the potential to ad-
versely affect a sensitive environment.
An industrial site. This consisted of a small wooded area
bordered by several factories. The soil in the woodland had
become contaminated with refuse from the factories. No ponds or
streams occurred on this flat site. In addition, the site's geology
indicated that ground water lay below an impervious layer. Be-
cause industrial plants surrounded the site, the site lacked surface
water, and its contaminants had no access to ground water, the
BTAG concluded that off-site migration of contaminants would
occur only through movement of biota.
A former landfill. This site consisted of a former landfill
operation located in a wetland that overlay a shallow aquifer.
Streams from the wetland fed a river protected by the State.
Residences and industrial facilities occupied the properties adja-
cent to the landfill. From this description, the BTAG concluded
that:
• As a wetland, this site merited special concern;
• The streams provided a means of off-site contaminant migra-
tion to the surrounding area;
• Migration of contaminants into the aquifer could occur, with
any discharge of ground water into surface water further
spreading the contaminants; and
• The river constituted a sensitive environment because it was
a body of water designated by the State for the protection of
aquatic life.
The Site's History
The site's history includes information about the events that
have resulted in its being designated a Superfund site. In general.
the PA and the SI recount the site's contaminant history, indicating
both the activities that caused the contamination and the length of
time over which these activities occurred. As with the setting, this
information helps the BTAG to develop a picture of the site. In
addition, such information can indicate contaminants potentially
associated with the site. Consider again the three hypothetical
Superfund sites described above.
The abandoned mine. The old mining site had been worked
for 30 years before its closing. For more than 30 years, then,
tailings had been exposed on the mountainside. From this informa-
tion, the BTAG discerned that contaminants from the mine had had
many years to leach into the soil, the streams that drain the
mountainside, and the sediments in these streams and that con-
tamination was on-going.
The industrial site. The contaminated woodland surrounded
by factories had had a shorter but more diverse history of contami-
nation than the nickel mine. Industrial activities, including electro-
plating and plastics manufacture, had been occurring in the build-
ings surrounding the site for 15 years. In general the plants had
accurate records of the chemicals and the amounts they had used.
From this information, the BTAG concluded that it had a clear and
complete account of the site's history and required no further
information on the site's history.
The former landfill. The landfill site presented a different
picture. Few records existed to show which chemicals the facility
received and in what amounts. The RPM learned that the operation
did not dispose of contaminants properly, frequently pouring
liquid wastes directly onto the ground. This sketchy history alerted
the BTAG that they could only guess at the precise nature and
extent of contamination.
The Contaminants of Concern
The BTAG will want to know what contaminants are associ-
ated with the site and in which media and in what concentrations
they occur. The RPM should also provide the BTAG with the
results of chemical analyses that have already been performed at
the site. The BTAG will want to know where samples were
collected and, where applicable, at what depth(s). The contractor
should research whether the contaminant levels exceed Federal
Ambient Water Quality Criteria, State WaterQuality Standards, or
other widely accepted screening values. The BTAG. in turn, may
compare a site's contaminant concentrations with concentrations
known to cause adverse ecological effects to biota.
If a site has a large number of contaminants, tracking all of
them may prove unwieldy. The BTAG may be able to advise the
RPM as to which contaminants to choose as contaminants of
concern. Alternatively, the BTAG may advise that additional
analyses be performed to document the presence of certain con-
taminants at specific areas of the site or in various media.
ECO Uodaie
August 1992- Vol. I. No.
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The abandoned mine. At the old mining site, the BTAG
recognized that soil, surface water, and sediment were all poten-
tially contaminated with metals. Since the chemical analyses
performed during the SI concentrated mainly on surface water, the
BTAG advised chemical testing of soil and sediment. In addition,
toe analyses of surface water lacked a reference site, so the BTAG
suggested that future analyses include an upstream water sample.
The industrial site. Because of the variety of industrial
facilities adjacent to the site, the initial site chemistry included both
inorganics and organics. Since some of the organics were volatile,
the SI had analyzed air as well as soil. The variety of contaminants
present at this site made it advisable for any future ecological
assessment to focus on a subset of the contaminants. To this end,
the BTAG advised the RPM as to which chemicals to consider the
contaminants of concern.
The former landfill. Because of the sparse history of the
landfill, the BTAG regarded both organics and inorganics as
potential contaminants and soils, sediments, surface water, and air
as potentially contaminated media. Consequently, the BTAG
advised chemical analyses more extensive than those conducted as
part of the SI. The BTAG also suggested that the RI examine
contamination of the river. As at the woodland site, this site had a
large number of contaminants, and the BTAG offered the RPM
advice on selecting contaminants of concern.
Ecological Description
This part of the site description helps the BTAG decide
whether the contaminants and their history at the site represent a
potential for ecological harm to the area associated with the site. In
preparing this description, the RPM should make full use of all
readily available information.
Central to an ecological description is a list of the habitats,
which are types of environments, associated with a site. These
include wetlands, woodlands, grasslands, open fields, ponds,
streams, estuaries, coastal zones, and other natural areas.
The ecological description also includes geological informa-
tion, such as hydrology, sediment types, and soil types. Conse-
quently, the RPM needs to describe all surface waters-lakes,
ponds, rivers, streams (including intermittent streams), and flood-
plains—in greater detail than was required for the site's setting. The
topographical maps published by the U.S. Geological Survey can
provide much of this information. Maps providing information
about floodplains include the Flood Insurance Rate Maps and the
Flood Hazard Boundary Maps published by the Federal Emer-
gency Management Agency. For areas largely owned by the State
or Federal government, the controlling agency generally has
information about floodplains. The SI may contain measurements
of soil and sediment parameters. Such information enables the
BTAG to decide whether the contaminants of concern are likely to
adsorb to the site's soil and sediment.
Whatever information the RPM has about plants and animals
in the site-associated area also belongs in the ecological descrip-
tion. In addition to species spending all or most of their time in the
site-associated area, this information should include migratory
species and species using the area during only part of their life
cycle. Some sites may have species of special interest, such as
game species. Federal- or Stale-listed endangered or threatened
species, or species protected under other statutes.
The abandoned mine. An ecological description of the old
mining site showed that it had no ponds or lakes but did contain a
number of fastflowing streams with hard, gravelly sediments. The
fishing stream into which these emptied had finer sediments. This
information led the BTAG to conclude that the streams with the
gravelly beds probably had little or no adsorbed contaminants but
the fishing stream's finer sediments may have adsorbed contami-
nants from the water column. As to the area's biota. State surveys
indicated that brook trout, minnows, dace, shiners, and suckers all
inhabited the streams. The local Audubon chapter provided a list
of bird species sighted in the area. Hunters routinely took deer and
occasionally bear. The team that made the site visit reported
spotting several squirrels and chipmunks and noted that vegetation
consisted largely of pine and birch trees with limited undergrowth.
The flora and fauna described for the site held no surprises for the
BTAG.
The industrial site. While researching the site, the investiga-
tor learned that a State-listed endangered species inhabited wood-
lands in this general area, raising the possibility that the site could
be home to members of this species. With respect to vegetation,
pine trees dominated the site, which also contained grasses and
shrubs. In places the dry sandy soil was bare of vegetation. The
BTAG suggested that the RPM have additional chemical analyses
performed on soil samples from this part of the site. No readily
available information existed as to the site's resident animals.
The former landfill Because this area was a wetland, the
BTAG had concerns about potential cross-media contamination
between soil and surface water. With respect to vegetation, the SI
noted that shrubs and grasses dominated the area's vegetation and
that the pollution-tolerant marsh plant Phragmites grew abun-
dantly at the site.
Known Ecological Effects
In addition to the ecological description, the investigator may
have information about known or suspected ecological harm at a
site. For example, the site may have an abundance of a "nuisance"
or pollution-tolerant species. Alternatively, an expected species
may be absent or present only in small numbers. Local sport and
nature groups or State agencies may have information about
changes in the condition or abundance of certain species.
The abandoned mine. In the course of routine surveys of the
fishing stream, the State noted that a decline in the population of
several species, including brook trout, had occurred over the past
ten years.
The industrial sue. The bare areas of the woodland site gave
evidence of ecological impact.
August 1992 • Vol. /, No. 5
ECO Update
-------
The former Landfill. The abundam growth of Phragmites,
known for its association with polluted wetlands, suggested a
disturbed ecological condition.
At this stage of the investigation, the available information
can only suggest possibilities for future study. Demonstrating a
causal link between site contaminants and ecological effects
requires considerably more evidence.
The STAG'S Preview
In many cases, this briefing represents the first time that the
BTAG has encountered the site. Having materials ahead of time
enables the group's members to familiarize themselves with the
site. By providing these materials, the RPM enables the BTAG to
give more thoughtful and informed advice about handling the site.
BTAG coordinators have indicated that members sometimes take
this opportunity to consult additional outside experts.
Precisely which materials the BTAG members ask to preview
varies considerably among the Regions. These documents could
include the documents relating to the site, such as the PA and the
SI; all materials that will be used at the meeting; or a 'distilled"
version of these materials. The RPM will need to check with the
BTAG coordinator to find out which materials to supply.
At the very least, however, the RPM should provide the
BTAG with a brief description and history of the site. Many BTAG
coordinators indicate that members find a copy of the SI helpful at
this time. In addition, a map of the site helps in following the details
of a site description. The RPM should include among the pre-
meeting materials the reasons for the site's listing and any addi-
tional information that has expanded the reasons for the listing.
The Meeting
EPA Regions have developed two ways of dealing with the
BTAG's first meeting concerning a site. In some Regions the RPM
introduces the site in a presentation that generally lasts no longer
than 30 minutes. The presentation covers the information that the
RPM has assembled; the site's setting, history, contaminants,
ecological description, and any evidence of ecological impact.
BTAG coordinators indicate that members find maps and photo-
graphs particularly useful visual aids at these briefings. Maps
should show the source of contamination, the direction in which it
is moving, and the nearest potentially exposed habitats (Figure 1).
In other EPA Regions, the BTAG gathers specifically to
discuss the SI or the document on which the RPM is currently
working. Here the RPM does not make a formal presentation.
Instead, be or she attends the meeting to answer questions and to
bear the BTAG's input first hand. Even in these Regions, however.
- the BTAG may expect the RPM to present a brief description of the
site's setting and a short account of its contaminant history.
The BTAG's Recommendations
An important part of this initial meeting is the open discus-
sion, during which BTAG members ask questions and develop
suggestions for the site. At this time, the BTAG will offer its
advice.
• The group may decide that a site does not pose a significant
present or future ecological risk. In such a case, the BTAG
will advise the RPM that the site does not require any further
ecological assessment.
• Before deciding what to recommend with regard to future
ecological studies, the BTAG may decide that the group
needs more information. In this case the BTAG's recommen-
dation will include suggestions as to the studies that could
provide the additional information.
• The BTAG's evaluation of the available data may lead it to
conclude that the site has a significant potential for ecological
impact and should undergo an ecological assessment The
BTAG will then offer advice on the types of studies that will
elicit pertinent information and the level of effort commensu-
rate with the adverse effect suspected.
Follow-Up of the Meeting
After the meeting has ended, the RPM will most likely want
a written record of the meeting's results. How such a record comes
into existence varies with the Region. In some Regions, the RPM
receives a copy of the minutes or a memorandum prepared by one
or more members of the BTAG. This document provides the RPM
with a copy of the BTAG's recommendations in the BTAG's own
words. Other Regions have the RPM prepare minutes, summariz'
ing both the presentation (if one occurred) and the BTAG's advice.
BTAG coordinators in these Regions say that this approach en-
ables them to confirm that the RPM has understood the group's
suggestions. Regardless of who prepares the record, it is generally
available no later than two weeks following the meeting.
The record of this first meeting constitutes a succinct descrip-
tion of the site, its contaminant history, and the BTAG's initial
recommendations. RPMs may wish to copy this record, along with
a map, to BTAG members to refresh their memories about a site the
next time it comes up for review. Alternatively, RPMs can accom-
plish the same end by copying the check sheet (see Appendix) to
BTAG members.
ECO Update
August 1992'Vol. l,No.5
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August 1992 • Vol. 1. No. 5
ECO Update
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Appendix A,: Check Sheet for Ecological Description of Site
Setting
1. What are the land uses/facilities in the vicinity of the site?
North
South.
East
West
What directions do contaminant gradients follow?
Surface water, sediment
Soil
Ground wate
2. What is the site's highest elevation?.
What is its lowest elevation?
3. Is the site readily accessible? Yes No
If No, explain:
4. For each pair of descriptors, circle the one that best describes the site.
wooded/open hilly/flat marshy/dry
Other
5. Does the site contain or drain into surface water? Yes No
IfYes,whattype(s)?
Pond or lake
Location
Area
Average Depth (or.deptb range).
ECO Update 7 August 1992 • Vol. 1. No. 5
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Scream or river (including intermittent streams):
Location
Length
Average Width (or width range
Average Depth (or depth range
Type(s) of bottom
How rate
Estuary/embayment:
Location
Area
Average Depth (or depth range).
Type(s) of bottom
List any known parameters of site-associated surface water.
pH Temperature Dissolved Oxygen.
Total Suspended Solids
Total Organic Carbon
Hardness
Salinity
Other (specify.
List any known sediment parameters of site-associated bodies of surface water.
Sediment type(s) —
Grain Size pH Eh pE
Total Organic Carbon
Acid-Volatile Sulttdes
Other (specify
(If more than one surface water body of each type, repeat information as needed.)
6. Does the site contain or drain into wetlands? Yes No
If Yes, what type(s) and size(s)?
List any known surface water and sediment parameters of site wetlands, as in #5, above.
August 1992 • Vol. I, No. 5 8 ECO Update
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7. Describe sub-surface hydrology.
Overlying strata
Aquifer
Depth to aquifer
Location of groundwater discharge
Ecological Description
8. List and describe habitats that occur at the site.
Woodlands
Grasslands/open fields
Wetlands
Ponds
Streams
Estuaries,
Coastal zones
Flood plains _
Other natural areas
List any known soil and sediment parameters for each terrestrial habitat.
Soil type(s
Grain Size pH Eh pE.
Total Organic Carbon
Total Phosphorus
Nitrogen forms
Other
9. Are any Federally or State listed endangered or threatened species known or suspected to occur on or near the site?
Yes No
If yes, list:
ECO Update 9 August 1992 • Vol. 1. No. 5
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1C. Does the site have any game species or species of interest for another reason? Yes No
If yes, list:
Known Ecological Effects
11. Does the site show any evidence of adverse ecological effects? Yes No
If yes, describe:
12. Documentation attached:
Site map(s)
PA
SI
Contaminant concentration data
Species Iist(s)
Preliminary Natural Resources Survey (PNRS)
Other (specify
August 1992 • Vol. I. No. 5 10 ECO Update
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USEPA Regional BTAG Coordinators/Contacts
EPA HEADQUARTERS
Ruth Bleyler
Toxics Integration Branch (OS-230)
OERR/HSED
USEPA
Washington, DC 20460
(703) 603-8816
(703) 603-9104 FAX
David Charters
ERT
USEPA(MS-101)
2890 Woodbridge Ave., Bldg. 18
Edison, NJ 08837-3679
(908) 906-6826
(908) 906-6724 FAX
Steve EUs
Elaine Suriano
OWPE
USEPA (OS-510)
401 M Street SW
Washington, DC 20460
(202) 260-9803
(202) 260-3106 FAX
Joseph Tieger
USEPA (OS-510W)
401 M Street SW
Washington, DC 20460
(202) 308-2668
REGION 1
Susan Svirsky
Waste Management Division
USEPA Region 1 (HSS-CAN7)
JFK Federal Building
Boston, MA 02203
(617) 573-9649
(617) 573-9662 FAX
REGION 2
Sharri Stevens
Surveillance Monitoring Branch
USEPA Region 2 (MS-220)
Woodbridge Avenue
Raritan Depot Building 209
Edison, NJ 08837
(908) 906-6994
(908) 321-6616 FAX
REGION 3
Robert Davis
Technical Support Section
USEPA Region 3 (3HW13)
841 Chestnut Street
Philadelphia, PA 19107
(215) 59--3155
(215) 597-9890 FAX
REGION 4
Lynn Wellman
WSMD/HERAS
USEPA Region 4
345 Courtland Street, NE
Atlanta, GA 30365
(404) 347-1586
(404) 347-0076 FAX
REGION 5
Eileen Helmer
USEPA Region 5 (5HSM-TUB7)
230 South Dearborn
Chicago, IL 60604-1602
(312) 886-4828
(312) 886-7160 FAX
REGION 6
Jon Rauscher
Susan Swenson Roddy
USEPA Region 6 (6H-SR)
First Interstate Tower
1445 Ross Avenue
Dallas, TX 75202-2733
(214) 655-8513
(214) 655-6762 FAX
REGION 7
Bob Koke
SPFD-REML
USEPA Region 7
726 Minnesota Avenue
Kansas City, KS 66101
(913) 551-7468
(913) 551-7063 FAX
REGION 8
Gerry Henningsen
USEPA Region 8
Denver Place, Suite 500
999 18th Street
Denver, CO 80202-2405
(303) 294-7656
(303) 293-1230 FAX
REGION 9
Doug Steele
USEPA Region 9
75 Hawthorne Street
San Francisco, CA 94105
(415) 744-2309
(415) 744-1916 FAX
REGION 10
Bruce Duncan
USEPA Region 10 (ES-098)
1200 6th Avenue
Seattle, W A 98101
(206) 553-8086
(206) 553-0119 FAX
BTAG Forum
11
September 1992
-------
v-/EPA
United States
Environmental Protection
Agency
Office of
Solid Waste and
Emergency Response
Publication 9345.0-051
March 1994 t
ECO Update
Office of Emergency and Remedial Response
Hazardous Site Evaluation Division (5204G)
Intermittent Bulletin
Volume 2, Number 1
Using Toxicity Tests in Ecological
Risk Assessment
Toxicity tests are used to expose test organisms to a
medium—water, sediment, or soil—and evaluate the effects of
contamination on the survival, growth, reproduction, behavior
and/or other attributes of these organisms. These tests may help
to determine whether the contaminant concentrations in a site's
media are high enough to cause adverse effects in organisms.
Generally, toxicity tests involve collecting samples of media
from a site and sending them to a toxicity laboratory, where the
tests are performed. On occasion, investigators' measure toxic-
ity by exposing test organisms to soil or water on site—these are
known as in situ tests.
As the general guidelines at the end of this Bulletin
indicate, not all sites require toxicity tests. But where they are
used, toxicity tests can contribute to ecological risk assessments
in specific ways and at different stages in the assessment
1. Toxicity tests can demonstrate whether contaminants
are bioavaiiable.2 The presence of a contaminant does not of
itself indicate a potential for ad verse effects. A contaminant can
have toxic effects only if it occurs in a bioavaiiable form.
Sometimes the presence of abrasives, such as the talc in pesti-
cides, can damage an organism's body covering, thereby in-
creasing the bioavailability of certain contaminants for that
organism.
2. Toxicity tests can evaluate the aggregate toxic effects
of all contaminants in a medium. Many Superfund sites present
a complex array of contaminants, with a mixture of potentially
harmful substances present in the media. At such sites, chemi-
cal data alone cannot accurately predict the toxicity of the
contaminants. Rather, toxicity tests measure the aggregate
effects of contaminated media on organisms. These effects
result from characteristics of the medium itself (such as hard-
ness and pH, in the case of water), interactions among contami-
nants, and interactions between contaminants and media. Con-
sequently, observed toxicity test results may often vary from
those predicted by chemical data alone.
3. Toxicity tests can evaluate the toxicity of substances
whose biological effects may not have been well characterized.
The contaminants at a Superfund site might include substances
that have not been previously investigated regarding their
toxicity to wildlife or other organisms. Consequently, the
scientific literature contains no relevant data concerning these
substances. At such sites, toxicity tests of media samples
' The term "investigator" refers to the individual charged with
responsibility for designing and/or carrying out any part of an ecologi-
cal risk assessment. Investigators can include government scientists,
contractors, or university scientists. However the site manager (reme-
dial project manager or on-scene coordinator) retains ultimate respon-
sibility for the quality of the ecological risk assessment.
2 Bioavailability is the presence of a substance in a form that
organisms can take up. (Note that specialized terms .appear in boldface
and are defined either in the text or in accompanying footnotes.)
IN THIS BULLETIN
Measurement Endpoints in Toxicity Testing 2
Elements in a Toxicity Assessment 3
General Guidelines for Choosing Toxicity Tests 9
ECO Update is a Bullet in series on ecological risk assessment of Superfund sites. These Bulletins serve as supplements to Risk Assessment Guidance
for Superfund, Volume II: Environmental Evaluation Manual (EPA/540-1-89/001). The information presented is intended to provide technical
information to EPA and other government employees. It does not constitute rulemaking by the Agency, and may not be relied on to create a
substantive or procedural right enforceable by any other person. The Government may take action that is at variance with these Bulletins.
-------
: 'lie?1 he <; cabined toxicity of all contaminants, including those
u ji h« ve not been previously tested.
4. Toxicity tests can characterize the nature of a toxic effect.
Investigators can use toxicity tests to learn whether contaminant
concentrations have lethal or sublethal effects. Some examples of
subleihal effects include reduced growth, impaired reproduction,
and behavioral changes.
5. Toxicity tests can characterize the distribution of toxicity at
site. An investigator can have toxicity tests performed on
samples from a variety of locations at the site. In some instances
toxicity tests may be a cost-effective way to determine the spatial
extent of toxicity and identify areas with high levels of toxicity.
6. Toxicity tests can be used to develop remedial goals,
Acceptable levels of toxicity, as measured by toxicity tests, can
form a criterion for remedial goals. For example, a goal might be
to reduce the toxicity of pond water over a stated time period. The
remedial goal would specify the level t which toxicity should be
reduced and the species in which toxicity should be measured. The
species should be representative of the site and sensitive to its
contaminants. The species also should relate to the overall assess-
ment endpoints.3
7. Toxicity tests have a role in monitoring. Toxicity tests can
be used to monitor the remediation of a Superfund site. Specifi-
cally, toxicity testing can indicate whether sources of contamina-
tion have been contained and whether remedial measures are
reducing toxicity.
8. Toxicity tests have a role in determining a site's post-
remediation potential to support a viable ecological community.
For example, if a stream or waterbody receives contaminants from
numerous sources, including a Superfund site, upstream toxicity
testing may help to determine what the water's potential for
supportingaviableecologicalcommunitymightbeiftheSuperfund
loadings are removed and the other sources remain unchanged.
Toxicity tests include a broad spectrum of tests, differing in
the species and exposure media they use and the effects they
measure. In making decisions about whether to conduct toxicity
tests, which tests to choose, and how many to perform, investiga-
tors are well advised to seek advice from qualified experts, such as
those serving on a Regional Biological Technical Assistance
Group (BTAG).4
This Bulletin first describes two major classes of toxicity
tests—acute and chronic—and then explores the elements that an
investigator needs to consider in planning toxicity tests. Finally,
the Bulletin offers general guidance on when to use toxicity tests
and how to select those appropriate to different sites. The compan-
ion document, "Catalogue of Standard Toxicity Tests for Ecologi-
cal Risk Assessment" (ECO Update Vol. 2, No. 2), provides an
annotated list of standardized tests appropriate for use with differ-
ent media
3 An assessment endpoint is an ecological characteristic thai may be
adversely affected by site contamination and that, at a Superfund site, can
help to drive remedial decision making (U.S. EPA, 1992).
Measurement Endpoints In
Toxicity Testing: Acute Vs.
Chronic Tests
Toxicity tests can measure lethal and/or sublethal effects^
These effects are known as measurement endpoints: that is, they
arc ecological attributes that may be adversely affected by expo-
sure to sue contaminants and that are readily measurable, hi
addition, each measurement endpoint is closely related to an
assessment endpoint. Because of this close relationship, a mea-
surement endpoint can approximate or represent the assessment
endpoint if the assessment endpoint is not amenable to direct
measurement (U.S. EPA, 1992).
Acute toxicity tests are short-term tests that measure the
effects of exposure to relatively high concentrations of chemi-
cals. The measurement endpoint generally reHects the extent of
lethality.
Chronic toxicity tests, on the other hand, generally are longer-
term tests that measure the effects of exposure to relatively lower,
less toxic concentrations. For a chronic toxicity test, the measure-
ment endpoint concerns a sublethal effect (e.g., reproduction,
growth) or both lethality and a sub-lethal effect.
Acute Toxicity Tests
A typical acute toxicity test exposes test organisms to a series
of dilutions of a site's medium and records deaths occurring over
a specified period of time, usually 24 to 96 hours. Results can be
analyzed by comparing percent mortality of organisms exposed to
site media to percent mortality for organisms exposed to uncoi
laminated media. (See section below entitled 'The Referem
Site.") Alternatively, results of an acute toxicity test can be
analyzed to estimate the dilution of the medium at which SO
percent of the organisms died. This dilution (also referred to as a
concentration), called the LCj,, is the median lethal concentration.
When an acute toxicity test reports an LCM, the test results usually
will specify the test duration, the test species, and the life cycle
stage of the test species (e.g., the fathead minnow 96 hour LCX).
Since LCJ0s are point estimates, which are estimates of the effects
from specific concentrations of contaminants, coefficients of varia-
tion can be calculated for them. (See section below entitled
"Statistical Analysis.")
4 These groups are sometimes known by different names, depending
on the Region. Readers should check with the appropriate Superfund
manager for the name of the BTAG coordinator or other sources,
technical assistance in their Region. A more complete description*
BTAG structure and function is available in "The Role of BTAGs in
Ecological Assessment" (ECO Update Vol. 1, No. 1).
March 1994'Vol. 2, No. 1
ECO Update
-------
With some lest organisms, lexicologists find death difficult to
determine unequivocally. In tests using such organisms, lexicolo-
gists evaluate another effect, such as immobilily, lhal correlaies
closely wilh death. As with death for a measurement endpoint,
results can be analyzed by comparing percent effect for organisms
exposed to site media and those exposed to uncontaminated media.
Alternatively, data can be analyzed to estimate the dilution at
which 50 percent of the organisms displayed the effect. This
dilution (also referred lo as a concentration), called me EC^, is the
median effective concentration. When an acute toxicity test reports
an EC50, the test results will specify the effect, the test duration, the
test species, and the life cycle stage of the test species. Like the
Acute toxicity tests are short-term
tests .at measure the effects of expo-
sure to relatively high concentrations
of chemicals.
Chronic toxicity tests generally are
longer-term tests that measure the
effects of exposure to relatively lower,
less toxic concentrations.
LCj,,, the ECj,, is a point estimate and a coefficient of variation can
be calculated for it
In still other approaches to evaluating results, the laboratory
analyzes the data for the Lowest Observed Effect Concentration
(LOEC), which is the highest dilution causing statistically signifi-
cant toxic effects, or the No Observed Effect Concentration
(NOEC), which is the lowest dilution at which no statistically
significant toxic effects occurred.5 Statistically determined using
hypothesis testing, LOECs and NOECs are not point estimates and
consequently coefficienls of variation cannot be calculated for them.
Chronic T^^icity Tests
A chronic toxicily lesi exposes lesi organisms 10 a series of
dilutions of a sile's medium and measures sub-lelhal effects, and
in some cases lethal effects as well. Sublethal effects may include
growth reduction, reproductive impairment, nerve function im-
pairment, lack of motilily, behavioral changes, and the develop-
mentof terata, which are structural abnormalities. Results can be
analyzed in several ways. One is simply by a direct comparison
5 As used in this Bulletin, LOEC is synonymous with Lowest
Observed Adverse Effect Concentration (LO AEC) and Lowest Observed
Adverse Effect Level (LOAEL), and NOEC with No Observed Adverse
Effect Concentration (NOAEC) and No Observed Adverse Effect Level
(NOAEL).
between percent effect occurring in organisms exposed to siu
media and those exposed to uncontaminated media. Other ap
proaches to analysis determine the EC^, the LOEC, or the NOEC
Ecological Significance of Sublethal Effects
Although it would be an oversimplification to extrapolati
from the outcome of chronic toxicity tests to ecological condition
at a Superfund site, site managers need to be aware that tin
sublethal effects that chronic toxicity tests measure in laboratone
are ecologically significant effects when they occur in the environ
ment. For example, reduced growth can lead to decreased produc
tion, smaller size, lower fecundity (eggs or young per female^
increased susceptibility to predation, and other effects. Reproduc
live impairment can reduce the population size and also brin
about changes in a population's age structure. Production c
individuals with terata can adversely affect a population becaus
these individuals have a lower growth ratt are generally unable t
reproduce, and have an increased susceptibility to predation.
A Comparison of Acute and Chronic Toxicity
Tests with Respect to Time, Cost, and
Resolution
In general, acute and chronic toxicity tests differ in th
amount of time required to perform them, their cost, and thei
resolution.
• Because chronic tests extend through either a life cycle or
critical developmental phase, they generally require mor
time to perform than acute tesls with the same type of te:
organisms.
• Requiring more time to complete than acute tests, chroni
tesis also can require more funds. A chronic test also ma
require more resources and increased numbers of laborator
analyses, further increasing Ihe cost of the test.
• Chronic tesls have greater resolution than acute lesis. Fc
example, consider a chronic test that exposes invertebrates t
site surface water and records the number of young the
produce. In a highly toxic medium, the organisms will die. 1
a less toxic medium, they may survive, but their reproducti\
capacity may be impaired when compared with contro
maintained in an uncontaminated medium.
Elements in a Toxicity
Assessment
The investigator needs to consider many elements wh<
planning a toxicity assessment: the objective, the reference site, tl
medium analyzed, the test organisms, the test methodology, tl
level of effort, the test site, and quality assurance/quality contr
(QA/QC) standards. By the choices that he or she makes, tl
investigator can tailor the toxicity assessment to meet the needs
the site and its stage in the Superfund process.
ECO Update
March 1994 •Vol. 2, No
-------
i"he Objective
A.S with any study, before planning a toxicity assessment the
investigator needs to set clear objectives. In particular, the
assessment* s objectives need to include some that address the
medium of concern, the characteristics of the contaminants of
concern, and the potential ecological components.6 For example,
ii the study asks whether soil on the site is toxic to
macroinvertebrates, then the study will need to analyze bulk soil
rather than an elutriate7 and will need to use an appropriate test
organism.
The objectives of a toxicity assessment should indicate the
level of effort appropriate to the assessment. For example, deter-
mining whether a particular medium is toxic would generally
require a low level of effort. Such a study might specify only two
species of test organisms and undiluted medium collected from a
limited number of sampling locations. If the objective of a toxicity
assessment is to determine the appropriate range of dilutions for
conducting further tests (if these p. ^ve necessary) at a highly
contaminated site, a higher level of effort would be necessary.
Such a study might specify using a series of tenfold dilutions of
media collected from locations known to have high contaminant
concentrations. A reasonably detailed characterization of a site's
toxicity would imply a high level of effort. This type of study might
include test organisms at different trophic levels' (such as an alga,
a macroinvertebrate, and a fish), several sampling locations (pos-
sibly based on a grid or selected from upstream and downstream
areas), and several dilutions of medium.
The Reference Site
When planning a toxicity assessment, an investigator selects
a reference site that as closely as possible mirrors the characteris-
tics of the site medium being analyzed but is unaffected by site
contamination. Analyzing a sample from the reference site allows
the investigator to measure background conditions. The investiga-
tor should try to locate the reference site as close as possible to the
Superfund site so that the reference site will accurately reflect the
site' s conditions. Yet the reference site should lie at a great enough
distance from the Superfund site to be unaffected by site contami-
nation. Provided that pollutant loading from other sources does not
occur upstrear" an upstream location may provide an appropriate
reference site for a Superfund site with contaminated surface
water. Soil type and texture, vegetation, and slope are important
considerations in selecting a reference site with the appropriate
terrestrial characteristics.
* An ecological component is an individual organism, a population,
a community, a habitat, or an ecosystem that may suffer adverse effects as
a result of site contamination.
7 An elutriate (or eluate) is the solution obtained when water re-
moves substances adsorbed to sediment panicles.
* A trophic level is a stage in the flow of food from one population
to another. For example, as primary producers (organisms that convert the
energy from sunlight to chemical energy) plants occupy the first trophic
level, and grazing organisms occupy the second trophic level.
The Medium
Toxicity tests vary as to the media they analyze. Aquatic tests
evaluate freshwater, marine, or estuarine samples. A few tests are
designed specifically to analyze bulk sediment samples, and a few^^
are specific for bulk, soil samples. Bulk sediment or soil test^B
specifically address toxicity in the test medium. Alternatively,
laboratory technicians can prepare elutriates of sediment or soil
samples and analyze the elutriates by means of aquatic tests.
Toxicity tests using elutriates give information about the transfer
of contaminants from sediment or soil to water. Such information
is most valuable when predicting effects of runoff or leaching from
soil or determining the advisability of remediating a site by
dredging contaminated sediments.
A toxicity test also should include measurements of the
appropriate physical and chemical parameters of the sample me-
dium. For water, these parameters might include alkalinity, hard-
ness, pH, temperature, dissolved oxygen, total dissolved solids,
and total organic carbon. For a sediment sample, grain size, percent
A toxicity test should include mea-
surements of the appropriate physical
and chemical parameters of the sample
medium.
water, pH, total organic carbon, and/or other parameters
prove important to know.
In some cases the physical or chemical parameters of the test
medium require adjustment in order to meet the conditions of a test
protocol. Sediment or soil may require dewatering. Water samples
may need to have their pH, hardness, or dissolved oxygen content
adjusted. Such adjustments can change the solubility,
bioavailability, or toxic properties of sample constituents and
therefore should be avoided or minimized wherever possible. If the
test medium requires adjustment, the investigator should allow a
portion of it to remain unadjusted. This unadjusted portion is used
in a parallel control that will indicate whether the adjustment
contributes to, masks, or has no effect on toxicity. In cases where
the test medium requires adjustment, the investigator should
evaluate thedata quality objectives (DQOs)9 to determine whether
the adjustments would interfere with the study's objectives.
For many toxicity tests investigators must dilute sample
media to determine LCsos, EC^s, LOECs, or NOECs. Protocols for
aquatic tests generally specify using specially treated laboratory
water as a diluent, but natural water can be used as well. Diluting
material for soils or sediments can consist of artificial soil prepared
in the laboratory.
' Data quality objectives (DQOs) are statements that define the level
of uncertainty that investigator is willing to accept in environmental d
used to support a remedial decision. DQOs address the purpose and use'
data, the resource constraints on data collection, and any calculations
based on the data.
March 1994'Vol.2,No. J
ECO Update
-------
Test Organisms
lexicologists have based their selection of test organisms on
several factors: sensitivity to a variety of substances, availability,
representativeness of a variety of ecosystems, and ease of mainte-
nance and culture under laboratory conditions. For aquatic tests,
the most frequently used test organisms are those employed for
toxicity testing for National Pollutant Discharge Elimination Sys-
tem (NPDES) permits. Table 1 summarizes information about the
organisms used in the standardized tests, while Figure 1 illustrates
a few of these organisms.
When choosing from among the available standard test or-
ganisms, the investigator should select a species thai is represen-
tative of resident organisms, sensitive to site contaminants, rel-
evant to the overall assessment endpoints, and consistent with
DQOs. In a toxicity test, the test organisms serve as surrogates for
organisms present on the site. For instance, although fathead
minnows (Pinu hales promelas), a comm n test organism, may
not occur on the site, they can serve as surrogates for other fish.
Consequently an LCJO for fathead minnows can serve as a measure-
ment endpoint for the assessment endpoint "survival of the min-
now populations in a specific stream that flows through the site."
In a broader context, fathead minnows might represent all warm-
water fish on a site, since research has shown that organisms at the
same taxonomic level (level of classification, such as genus or
family) often respond similarly to a contaminant (Baker, 1989).
When selecting test organisms, the investigator should keep the
study's DQOs in mind. If the investigator's selection is not
consistent with the DQOs, the applicability of the test data to the
site is questionable.
Although the existence of well-established protocols and
considerable historical data makes the standard test organisms
useful, in some cases investigators find that none of the standard
organisms is representative of a site's ecosystem. If this situation
When choosing from among the\
available standard test organisms, the
investigator should select a species
that is representative of resident
organisms, sensitive to site contami-
nants, relevant to the overall assess-
ment endpoints, and consistent with
DQOs.
occurs, the investigator must account for this lack of representa-
tiveness when interpreting test results. Alternatively, the investi-
gator may decide to use a "non-standard" or alternative species
instead of the one specified in the test protocol. The alternative
species might better represent resident organisms, show greater
sensitivity to the site's contaminants, or be more consistent with
the study's DQOs. State resource agencies can readily provide
information on resident species. Using resident species as ar
alternative species has the potential of providing direct informa
lion about the toxic effects to site species. Several criteria must tx
specified for the use of alternative test species, including the sourci
for the test organism, the age range suitable for the test, a means fo
eliminating variability in the organism's condition, and condition:
suitable for the test. In addition, if the organism must be collecte<
rather than purchased, the investigator will have to establisl
standards for ensuring accurate identification and also should mec
all local, state, and federal requirements concerning the collectioi
of organisms.
Generally, using alternative species increases the cost o
conducting toxicity tests, especially when the investigator needs u
determine optimal conditions for conducting the test. However
the investigator, in consultation with the BTAG, may decide tha
the added usefulness of the results just;" 2s he extra expense, li
such a case, the investigator may be able to reduce the adda
expense by employing a laboratory experienced in the use of tin
species selected for the study.
Test Method
Standard toxicity tests can employ a variety of methods fo
collecting samples and for exposing test organisms to medk
Designing a toxicity assessment for a site requires the investigate
to select the most appropriate methods for studying the issues fc
that site.
Field biologists can collect media samples for testing eithe
by the grab or the composite method. As the name implies, a gra
sample is a single sample, usually entailing little time and minim;:
equipment to collect. When the investigator expects the site'
contam inant picture to change little over time, a single grab sampl
per location may adequately represent contamination. A compos
ite sample, on the other hand, is a mixed sample, which may b
collected at a single location over a specified period of time or 2
multiple locations at one time. When sampling a stream with
highly variable flow rate, the investigator can specify the collec
lion of a flow weighted composite sample. The BTAG can advis
the investigator as to the preferred collection method for a partici
lar site.
Toxicity tests analyzing water or elutrites of soil or sedimei
can expose test organisms using the same sample medium througl
out the test or arranging for limited replacement of medium. Tho<
using the same sample medium throughout are called static test
while static-renewal tests are those that replace all or pan of tr
sample medium at specified times during the test Since th
approach requires little space, manpower, and equipment, stat
tests are comparatively simple and inexpensive to perform. 1
addition, static tests require only small sample volumes of one i
20 liters.
On the other hand, static tests, particularly those withoi
renewal of media, do have certain limitations. Over the course <
a non-renewal test, test organisms can deplete the dissolve
oxygen in the sample and suffer adverse effects unrelated 1
toxicity. Alternatively, contaminants can break down, volauliz
or adhere to the walls of the container. As a result, the test migl
not accurately reflect the medium's toxicity. Finally, as organisn
metabolize they release substances, such as carbon dioxide ar
ECO Update
March 1994-Vol. 2, No.
------- An error occurred while trying to OCR this image.
-------
Figure 1. Test Organisms Commonly Used In Toxlclty Tests
The organisms shown in these figures are the adult life
stages of the test organisms, not necessarily those life
stages used in toxicity tests.
Fathead minnow (Pimephales promelas)
50 mm.
Watertlea (Daphnia)
up to 3.5 mm for Daphnia pulex
Mysid shrimp (Mysidopsis)
4.4 to 9.4 mm for Mysidopsis bahia
Purple sea urchin
(Stronglyocentrotus purpuratus)
6 to 12 cm
Macroalga (Champia)
Actual size of branch tip 25 mm.
Marine amphipods
Species used in toxicity tests usually
3-6 mm.
Reproduced by courtesy of Aquatic Research Organisms,
P.O.Box 1271, Hampton, NH 03842.
ECO Update
March 1994-Vol. 2, No.
-------
w tes, calkA, metabolites. As these metabolites accumulate, they
can prove toxic to the test organisms. Alternatively, they may
interact with contaminants and alter the medium's apparent toxic-
ity. The static-renewal design overcomes to a certain extent the
disadvantages of the nonrenewal design.
In place of the static design, aquatic toxicity tests may use a
How-through method, continuously pumping fresh sample me-
dium through test chambers. With this method, dissolved oxygen
remains relatively high and metabolites are flushed away. The
flow-through approach also has the advantage of minimizing loss
of toxics to degradation, adsorption, and volatilization. When
conducted on-site, flow-through tests can provide information
about fluctuations in toxicity.
Disadvantages of the flow-through method include its ex-
pense and inconvenience. This approach uses complex equipment
that requires more maintenance than the equipment used for static
tests. Large volume- "«f sample and diluent arc needed for flow-
through tests. As a ,sult, these tests are more expensive than
equivalent static tests.
Level off Effort
The quantity and nature of information provided by toxicity
tests varies considerably with the level of effort mandated by the
study's objective. One factor determining the level of effort is the
number of species used as test organisms. When the investigator
selects a test species that is quite sensitive to the site's contami-
nants relative to other types of organisms in the community, then
a single-species test can suggest the community's maximum
susceptibility to the site's contaminants. At a higher level of effort,
employing more than one test species may indicate whether single-
species tests have underestimated or overestimated the site's
toxicity. However, when evaluating water, toxicity tests should
always include at least two species, a fish and an invertebrate,
unless the site has only one contaminant and either fish or inverte-
brates are known to be insensitive to that contaminant.
The level of effort also varies with the range of media
concentrations analyzed and the duration of the tests.
• Screening tests, which may be either acute or chronic tests,
evaluate only the undiluted sample. Positive values on screen- .
ing tests may indicate the need to proceed to definitive tests.
• Range finding *»sts are abbreviated static acute tests that
expose test organisms to a broad range of media dilutions for
8 to 20 hours. Such tests identify the dilutions to use for
definitive tests.
• Definitive tests provide a dose-response curve and reduced
variability. Both acute and chronic tests can be conducted as
definitive tests.Investigators can use these three types of tests
to translate "level of effort" objectives into appropriate tox-
icity assessments.
Test Site: Laboratory or in situ
In general, toxicity tests are conducted by collecting samples
from a site and sending them to a laboratory for testing. Laboratory
tests offer the advantage of standardized protocols. In addition,
laboratories experienced in performing these tests are generally
available.
Alternatively, toxicity tests can occur in situ, which means "in
place." That is, the investigator exposes test organisms to soil or
water on the site. In situ tests give organisms continuous exposure
to the site media under actual environmental conditions such
temperature, stream flow, and light.10 Consequently, data from i
situ tests provide a more realistic assessment of toxicity than do
data from laboratory tests. In situ tests also provide a more direct
means of comparing toxicity data with estimates of exposure
derived from field data. Ultimately, such comparisons help to
characterize the site's ecological risk.
On the other hand, in situ tests have certain disadvantages. In
particular, the investigator lacks control over the conditions under
which an in situ test occurs. For example, temperature may vary
considerably over the course of an in situ test, whereas in the
laboratory temperature would be carefully regulated. When inter-
preting data from in situ tests, the investigator should consider how
the varying conditions of the test could affectresv'ts. Another issue
associated with in situ tests concerns logistics, which c^n prove
difficult in adverse weather conditions.
At the present time, in situ tests generally consist of standard
laboratory tests adapted for on-site use. Some commonly used tests
employ earthworms or lettuce seeds as standard test organisms for
soil toxicity tests. For in situ aquatic toxicity tests, fish, clams, and
oysters are often used. Tests may instead use alternative orresident
species. In practical terms, to conduct in situ tests, test vegetation
is maintained in plots and test animals are held in containers on site.
The earthworm test, in particular, has been successfully adapted
for in situ use. In fact, some field biologists routinely perform this
test in sit u rather than having personnel conduct it as a laborato
test.
Statistical Analysis
The statistical analysis of toxicity test results depends upon
the measurement endpoint. As mentioned earlier, LC^s and ECMs
are point estimates; that is, they are estimates of effects from
specific dilutions of contaminants. To calculate point estimates,
test data are analyzed using regression models that assume the less
dilute the sample, the greater will be the effects. Coefficients of
variation can be calculated for point estimates.
LOECs and NOECs compare results at test dilutions with
controls to determine whether the results are significantly differ-
ent. LOECs and NOECs are calculated by mcjns of a statistical
method called hypothesis testing. Coefficients of variation cannot
be calculated for values determined using hypothesis testing. Note
too that the values obtained for LOECs and NOECs can vary
considerably depending on the specific series of dilutions used in
the test
For detailed information concerning statistical analysis of
toxicity test data, investigators can consult Weber et al. (1988,
1989 1991).
10 In situ tests should not be confused with tests performed in
mobile laboratory brought to the site. A mobile laboratory performs
toxicity tests under standard laboratory conditions, not site conditions.
March 1994 • Vol. 2. No. 1
ECO Update
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Quality Assurance/Quality Control (QA/QC)
Standards
The investigator must specify standards for quality assurance
and quality control (QA/QC) to ensure that toxicity tests produce
reliable results. QA/QC standards describe appropriate sample
handling and collection. Such matters as the container type,
storage temperature, and maximum permissible storage time af-
fect the reliability of data. For example, elapsed time and exposure
to air can alter sample properties or result in the loss of volatile
chemicals.Generally,aquatic samples should be stored at4*C until
used. Although holding time limitations for sediments vary with
individual sediment properties and contaminant characteristics,
the American Society for Testing and Materials (ASTM) recom-
mends storing sediments at 4'C and using them within two weeks
of collection.
Test parameters should specify which controls to perform and
what values to accept for controls. Forexamp—, in an acute toxicity
test with Daphnia pulex, a control consists of test organisms
exposed to dilution water only. For test results to be considered
valid, at least 90% of the animals in the control must survive the
test.
Finally, QA/QC measures need to ensure that the data col-
lected can support the appropriate statistical analysis.
The BTAG can advise the investigator as to whether the
proposed QA/QC standards are adequate.
General Guidelines for Choosing
Toxicity Tests
In an ecological risk assessment of a Superfund site, the
investigator must decide whether toxicity testing will contribute to
the assessment and, if so, which and how many tests to perform.
The great differences among Superfund sites—differences in size,
terrain, and contaminant profile, to name a few—make a rigidly
standardized approach to toxicity studies unworkable . However,
a few widely accepted general guidelines do exist:
• Do not perform toxicity studies at a site where the contami-
nants of concern do not cause effects measured by toxicity
tests. For example, polychlorinated biphenyls (PCBs) bring
about reproductive effects that many toxicity tests do not
detect. The investigator should consult the BTAG to find out
whether toxicity tests can detect the type of effects caused by
a site's contaminants.
• At a site where several substances have contaminated surface
water, aquatic toxicity testing generally should include both
a fish and an invertebrate species. At some sites, it may prove
advisable to include additional test organisms, as well.
• Select test organisms that arc sensitive to the site contami-
nants. For example, among standard freshwater test organ-
isms, water fleas of the genus Ceriodaphnia and the embryos
and larvae of fathead minnows are sensitive to a broad
spectrum of contaminants. Of the two species of midges used
to conduct standard tests of freshwater sediments, Chironomus
riparius is the choice when metals are the contaminants of
concern. When conducting initial tests of saltwater species,
it is usually appropriate to use a grass shrimp, penaeid shrimp,
or mysid, because these invertebratesoften are more sensitive
than fish. As a final example, algae should be used for initial
tests when herbicides and materials with suspected phytotox-
icity are detected in fresh or salt water.
These are only a few examples of how test organisms diffei
in their sensitivity to contaminants. Again, investigators wil
want to consult the BTAG for assistance in selecting appro
priate test organisms.
• When testing water, select a test organism that can tolerate tht
water's condition. For example, some organisms, such as thi
waterflea Ceriodaphnia, are extremely sensitive to water hard
ness. Also, certain inland waters have high enough salinity u
make the use of freshwater test organisms inadvisable.
To extend the limited guidelines offered above, several EPS
scientists were interviewed to leam how they design toxicit;
assessments. Each scientist offered a somewhat different outlin
and set of priorities. These differences reflect differences in sit
characteristics and geography, such as degree of urbanization am
amount of rainfall. In spite of the great variety in hazardous wast
sites, three general designs for toxicity assessments emerged fror
these interviews. The following section presents the design;
Where a design refers to specific toxicity tests, these are describe
in the companion Bulletin, "Catalogue of Standard Toxicity Tesl
for Ecological Risk Assessment" (ECO Update Vol. 2, No. 2).
Design 1
Design 1 is based on the premise that designing a meaningfi
toxicity assessment requires considering a contaminant's mode c
action, the level of site contamination, the sensitivity of the tei
type (acute or chronic), and the sensitivity of the test organism. 1
particular, sites are first reviewed to determine whether contam
nants are expected to cause effects detectable by toxicity tests th;
meet the stated DQOs for that site. The investigator then matchf
contaminant levels with test type. For example, in a heavi
industrialized site with high levels of contaminants, many of tl
samples in a chronic test may give highly positive results. Cons
quently, the study would provide little information about diffe
ences in toxicity at various locations on the site. At such a sit
acute tests might distinguish the varying toxicity of diffcre
locations, thereby identifying the more highly impacted areas ai
helping to establish priorities for remedial decisions.
Similar concerns are addressed when choosing test orga
isms: too sensitive a test organism results in a lack of discrimin
tion and too insensitive a test organism can give negative resu
that are misleading. Also, Design 1 uses screening tests sparinp!
because these tests may suffer from over-interpretation of resul
Design 2
Design 2 focuses on planning toxicity assessments for sil
where chemical data do not clearly indicate whether the s
contaminants represent an ecological problem requiring furtl
action. The premise is that sites with intermediate levels of cc
lamination will most likely require toxicity testing. Where lit
ECO Update
March 1994-Vol. 2. No
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:o«ir-'-vinatior: has occurred, the chemical data will generally
indicate that the site is not an ecological problem and requires no
further ecological risk assessment. A heavily contaminated site
will almost certainly require further action.
With this design, the investigator decides on ecological
components and endpoints as early as possible, making use of all
die information available about the site and its contaminant his-
tory. The ecological components and endpoints then serve to guide
choices of both toxicity tests and field studies.
If the chemical data indicate the need for toxicity tests, as
reflected by the literature, the investigator next decides which
media to test. Contamination may have migrated from the initial
contaminated medium into other site-associated media. Toxicity
test selection occurs next, with the choice between acute and
chronic tests depending on the objectives. In the long run, gauging
toxicity based on the sub-lethal effects measured by chronic tests
proves more protect" -e. In addition, chronic te<"s are considered
more appropriate if ^i organism spends most u its time on-site.
Conversely, acute tests better mimic conditions for organisms thai
spend a limited amount of time on-site, such as migratory animals
or those with a large home range. Acute tests also prove useful
when the investigator has concerns about significant differences in
toxicity at different locations on the site. If initial tests show no
toxic "hot spots," then further testing may not be necessary.
Design 2 puts toxicity testing in perspective by viewing the
ecological risk assessment of a Superfund site as a triad consisting
of chemical testing, toxicity testing, and field study:
• Chemical testing indicates the presence of contamination.
• Toxicity tests then explore whether biological effects are
possible.
• Field studies investigate whether actual harm has occurred at
the site.
At a highly contaminated site, each leg of the triad will most
likely give evidence of impact. At many sites, however, results are
notclear-cut. For example, toxicity results might not correlate well
with chemical data. Alternatively, field studies might not demon-
strate adverse ecological effects. Such sites require careful profes-
sional judgment to make a decision regarding ecological effects
and the need for remediation.
Design 3
Design 3 begins with a site reconnaissance visit, followed by
a "desktop assessment" to determine whether a site requires an
ecological risk assessment. The desktop assessment considers the
site's background from scoping and also its contaminants, their
environmental concentrations, their physical and chemical proper-
ties, and the nature of the surrounding area. A site located in an
urban industrial area, for example mpy "or r?qv;.re an ecological
risk assessment: the site itself may have no ecological components
of concern, and the contaminants may not have a means of
migrating to areas having potential ecological components. On the
other hand, the existence of a conduit—a stream, a drainage ditch,
ground-water gradient, or land grade—that could carry contami-
nants from the site to surface water, wetlands, or terrestrial habitats
would indicate the need for an ecological risk assessment In this
design, toxicity studies are viewed as useful tools and an effective
use of Superfund resources at sites requiring ecological risk
assessments.
Selection of sampling locations is one of the first tasks
undertaken when designing a toxicity study using this designf
Especially at large sites, the investigator avoids random sampling,
which would generate an unmanageably large number of samples
to analyze. Instead, site terrain and contaminant history are care-
fully studied in order to place sampling points in areas that will
extend the knowledge of the site. As a general rule, at a site with
contaminated surface water, the sampling plan should specify
sufficient samples to characterize fully the potential ecological
effects.
When testing samples of surface water, the investigator
selects an initial battery of screening tests from among the stan-
dardized acute tests used in the NPDES permitting program. These
initial tests usually include organisms at three trc ohic levels (e.g.,
an alga, an invertebrate, and a fish). If screening level tests show
that surface water is toxic, further tests include surface water
dilutions and additional lest species to characterize the site's
toxicity more fully.
This design favors performing initial soil or sediment evalu-
ations at the screening level using either bulk samples, laboratory-
prepared elutriates, or pore water, the water located between
particles and obtained by either centrifugation or filtration. Like
surface water samples, elutriates and pore water samples are
analyzed using screening level NPDES aquatic tests. If these tests
give positive results, the investigator reviews the chemical data
and contaminant history for the site before making the serious
commitment of resources that testing of bulk soil or sedimq
entails.
Conclusion
The differences in these three designs largely reflect the fact
that an ecological risk assessment of a Superfund site needs to
address the site's characteristics and contaminant history. As
scientists gain more experience in conducting toxicity assess-
ments, the several designs existing today may evolve toward a
common blueprint that will readily accommodate site differences.
In addition to reflecting site differences, the designs also reflect
strategic differences in the deployment of resources, time, and
As scientists gain more experience
in conducting toxicity assessments,
the several designs existing today may
evolve toward a common blueprint
that will readily accommodate site
differences.
March 1994 • Vol. 2, No. 1
10
ECO Update
-------
personnel. Despite these differences, however, the designs have
the same end: to assess the toxicity of contaminated media from
Superfund sites.
To learn about other designs for toxicity assessments, inves-
tigators may wish to consult the scientists in the EPA Environ-
mental Services Division (ESD) in their Region. In making
decisions about toxicity testing at a specific site, an investigator
should consult with the Regional BTAG. The BTAG will be able
to tell the investigator whether the Region has a standard design for
toxicity assessments. If the Region does not, the BTAG can advise
the investigator whether one of the above designs, one offered by
the ESD, or a modification of any of these will further the
ecological risk assessment of a particular site. Alternatively, the
BTAG may suggest another design that is better suited to a
particular site.
References
American Society for Testing and Materials (ASTM). 1992a.
Annual Book of ASTM Standards: Water and Environmental
Technology, Vol. 11.04. American Society for Testing and
Materials, Philadelphia, PA.
American Society for Testing and Materials (ASTM). 1992b.
Standard Guide for Conducting Sediment Toxicity Tests with
Freshwater Invertebrates. American Society for Testing and
Materials, Philadelphia, PA.
American Society for Testing and Materials (ASTM). 1992c.
Standard Guide for Conducting 10-day Static Sediment Tox-
icity Tests with Marine and Estuarine Amphipods. American
Society for Testing and Materials, Philadelphia, PA.
Baker, J.P. 1989. "Assessment Strategies and Approaches" in
Warren-Hicks, W., B.R. Parkhurst, and S.S. Baker Jr., eds.
Ecological Assessment of Hazardous Waste Sites: A Field
and Laboratory Reference. EPA/600/3-89/013. Environ-
mental Research Laboratory, Office of Research and Develop-
ment, U.S. Environmental Protection Agency, Corvallis; OR.
Bitton, G., BJ. Dutka, and C.W. Hendricks. 1989. "Microbial
Toxicity Tests" in Warren-Hicks, W., B.R. Parkhurst, and
S.S. Baker Jr., eds. Ecological Assessment of Hazardous
Waste Sites: A Field and Laboratory Reference. EPA/600/3-
89/013. Environmental Research Laboratory, Office of Re-
search and Development, U.S. Environmental Protection
Agency, Corvallis, OR.
Greene, J.C., C.L. Bartels, W.J. Warren-Hicks, B.R. Parkhurst,
G.L. Linder, S.A. Peterson, and W.E. Miller. 1989. Protocols
for Short-Term Toxicity Screening of Hazardous Waste Sites.
EPA/600/3-88/029. Environmental Research Laboratory,
Office of Research and Development, U.S. Environmental
Protection Agency, Corvallis, OR.
Linder, G. etal. 1992. Evaluation of Terrestrial Indicators for
Use in Ecological Assessments at Hazardous Waste Sites.
EPA/600/R-92/183. Environmental Research Laboratory,
Office of Research and Development, U.S. Environmental
Protection Agency, Corvalhs, OR.
U.S. Army Corps of Engineers. 1993. Evaluation of Dredged
Material Proposed/or Discharge in InlandandNear Coastal
Waters — Testing Manual (Draft). Office of Water, Wash-
ington, DC.
U.S. Environmental Protection Agency. 1992. Framework for
Ecological Risk Assessment. EPA/630/R-92/001. Risk As-
sessment Forum, Washington, DC.
Weber, C.I. 1991. Methods for Measuring the Acute Toxicity oj
Effluents and Receiving Waters to Freshwater and Marine
Organisms. 4th edition. EPA/600/4-90/027. Environmental
Monitoring Systems Laboratory, Office of Research and
Development, U .S. Environmental Protection Agency, Cincin-
nati, OH.
Weber, C.I., W.I. Homing, D.J. Claim, T.W. Nciheisel, P.A
Lewis, E.L Robinson, J. Menkedick, and F. Kessler. 1988
Short-term Methods for Estimating the Chronic Toxicity oj
Effluents and Receiving Waters to Marine and Estuarint
Organisms. EPA/600/4-87/028. Environmental Monitorinj
and Support Laboratory, Office of Research and Develop
ment, U.S. Environmental Protection Agency, Cincinnati
OH.
Weber, C.I., W.H. Peltier, T.J. Norberg-King, W.B. Horning II
F. Kessler, and J. Menkedick. 1989. Short-term Methods fo,
Estimating the Chronic Toxicity of Effluents and Receivin(
Waters to Freshwater Organisms. 2nd edition. EPA/600/4
89/001. Environmental Monitoring Systems Laboratory
Office of Research and Development, U.S. Environments
Protection Agency, Cincinnati, OH.
ECO Update
11
March 1994-Vol. 2. No.
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March 1994-Vol. 2, No. 1
12
ECO Update
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v°/EPA
United States
Environmental Protection
Agency
Office of
Solid Waste and
Emergency Response
Publication 9345.0-051
March 1994
ECO Update
Office of Emergency and Remedial Response
Hazardous Site Evaluation Division (5204G)
Intermittent Bulletin
Volume 2, Number 2
Catalogue of Standard Toxicity Tests
for Ecological Risk Assessment
This Bulletin, which serves as a companion to "Using
Toxicity Tests in Ecological Risk Assessments" (ECO Up-
date Vol. 2, No. 1), consists of an annotated list of standard-
ized aquatic, sediment, terrestrial, and microbial toxicity
tests currently in use at Superfund sites. Future Bulletins will
address new approaches to measuring toxicity as they be-
come available.
In addition to the standardized approaches described in
this Bulletin, the literature describes many other toxicity
tests. In some cases, an investigator may identify a non-
standard test that appears more relevant to a site and its
contaminant picture than the standardized tests. Before
deciding to use the non-standard test, the investigator should
ascertain that the test is both repeatable and logical. The
BTAu can assist the investigator in making a sound decision.
Most of the terms used in this document are defined in
the companion Bulletin. Reference numbers in the «ext
indicate source documents (listed at the end of this Bulletin)
that more fully describe test protocols. In the case of acute
aquatic toxicity tests, the catalogue also directs the reader to
sources describing additional standardized tests.
IN THIS BULLETIN
Aquatic Toxicity Tests 1
Sediment Toxicity Tests 3
Terrestrial Toxicity Tests 3
Microbial Toxicity Tests 3
References 4
Aquatic Toxicity Tests
The aquatic toxicity tests described here are the most com-
monly used tests and are highly standardized. Investigators1 should
have little difficulty identifying laboratories capable of perform-
ing them.
While these tests have the advantage of wide acceptance and
well-established protocols, other tests can contribute to the eco-
logical risk assessment of Superfund sites. The references at the
end of this Bulletin include sources of information about many
such tests. The Regional Biological Technical Assistance Group
(BTAG)2 also is a source of information about toxicity tests that are
especially well suited for use at a particular site.
Acute Freshwater Toxicity Tests
The following two tests measure the lethality of water sampLs
to freshwater organisms, indicating the toxicity of water samples.
'The term "investigator" refers to the individual charged with
responsibility for designing and/or carrying out any part of an ecological
risk assessment Investigators can include government scientists, contrac-
tors, or university scientists. However, the site manager (remedial project
manager or on-site coordinator) retains ultimate responsibility for the
quality of the ecological risk assessment.
2 These groups are sometimes known by different names, depending
on the Region, and tot all Regions have established BTAGs. Readers
should check with the appropriate Superfund manager for the name of the
BTAG coordinator or other sources of technical assistance in their Region.
A more complete description of BTAG structure and function is available
in "The Role of BTAGs in Ecological Assessment" (ECO Update Vol. 1,
No. 1).
ECO Update is a Bulletin series on ecological risk assessment of Superfundsites. These Bulletins serve as supplements to Risk Assessment Guidance
for Superfund, Volume II: Environmental Evaluation Manual (EPA/540-1-89/001). The information presented is intended to provide technical
information to EPA and other government employees. It does not constitute rulemaking by the Agency, and may not be relied on to create a
substantive or procedural right enforceable by any other person. The Government may take action that is at variance with these Bulletins.
-------
' y ;iv described in detail in Reference 5.
The Daphnia pulex or Daphnia magna acute toxicity test
evaluates acute toxicity of a sample to a water flea belonging to the
genus Daphnia. The test uses a static or static-renewal design and
lasts 24, 48, or 96 hours. Observations at 24, 48, and 96 hours
i«rmii the calculation of 24-, 48-, and 96-hour LC values.
Thf fathead minnow (Pimephales promelas) acute toxicity
test lasts 24, 48. or 96 hours and uses a static or static-renewal
design. Observations at 24,48, arid 96 hours permit the calculation
of 24- and 48-, and 96-hour LC values.
Two documents describe additional acute freshwater toxicity
tests. Methods for Measuring the Acute Toxicity of Effluents and
Receiving Waters to Freshwater and Marine Organisms (Refer-
ence 6) describes acute toxicity tests with three species of freshwa-
ter fish and three invertebrate species. The test organisms include
both warm-water a1"* cold-water species. The guide includes range
finding and definit i tests.
The second document, Annual Book of ASTM Standards:
Water and Environmental Technology (Reference 1), contains
guidelines for acute toxicity tests and sediment elutriate tests using
freshwater fish, macroinvertebrates, and amphibians. The guide-
lines describe static, static-renewal, and flow-through techniques
and recommend that investigators consider EC50s along with
lethality.
Chronic Freshwater Toxicity Tests
These tests measure both lethal and sublethal effects over the
life cycle or partial life cycle of freshwater organisms, providing
information useful in assessing the potential long-term effects of
contamination. Originally developed for the NPDES permitting
program, the tests have since been used in assessing the toxicity of
water associated with waste sites. All of these tests are described
in Reference 8.
The Ceriodaphnia dubia survival and reproduction test
estimates chronic toxicity of a sample to Ceriodaphnia dubia,
which is a water flea. The test uses the static-renewal design and
lasts for seven days, monitoring both the survival of test organisms
and the number of offspring they produce.
The fathead minnow (Pimephales promelas) larval sur-
vival and growth test uses the static-renewal design and lasts for
seven days, tracki*"* the survival of test organisms and their
increase in weight.
The fathead minnow (Pimephales promelas) embryo-lar-
val survival and teratogenicity test assesses the chronic loxicity
of a sample to minnows, beginning as embryos and extending to
the larval stage. The test uses the static-renewal design and lasts for
seven days, noting both the survival of the fish and the induction
ofterata.
The algal (Selenastrum capricornutum) growth test identi-
fies both biostimulatory3 and chronic toxic effects of a sample to
a one-celled freshwater alga. The test uses the static design and
lasts 96 hours, most commonly monitoring cell density (cells per
mL). Alternative measures include biomass (weight of living
matter), chlorophyll content, or light absorbance.
Acute Marine Toxicity Tests
These tests measure short-term lethality of media to marine
and estuarine organisms. Protocols differ little from acute toxicity
tests for freshwater organisms, with the marine/estuarine tests
incorporating the appropriate species substitutions and test condi-
tion adjustments.
The static acute toxicity test using larvae of bivalve
lusks evaluates the acute toxicity of test media to one of fou*"
species of bivalve mollusks (invertebrates such as clams, with two-
piece shells). The test lasts 48 hours and notes abnormal shell
development. (See Reference 1.)
The static acute toxicity test using silver-sides (Menidia
species) or sheepshead minnow (Cyprinodon variegatus) evalu-
ates the acute toxicity of test media to these fish species. The
screening test lasts 24 hours and the definitive test 48 hours. Both
record mortality as a lack of movement. (See Reference 6.)
Two documents describe additional acute marine toxicity
tests. The Annual Book of ASTM Standards: Water and Environ-
mental Technology (Reference 1) contains g, idelines for tests
using marine and estuarine fish and macroinvertebrates. This
volume presents a variety of tests including static, static-renewal,
and flow-through designs. Test durations vary from two to eight
days, depending on the species selected.
The second document, Methods for Measuring the Acute
Toxicity of Effluents and Receiving Waters to Freshwater and
Marine Organisms (Reference 6) provides protocols for tests
using four species of marine and estuarine fish and one invertebrate
species. The test organisms include both warm-water and cold-
water organisms. Range finding and definitive tests are repre-
sented in the guide. Duration and test conditions vary with the
species and specific test selected.
Chronic Marine Toxicity Tests
The following tests measure both lethal and sublethal effects
over the life cycle or partial life cycle of marine and estuarine
organisms, providing information about the potential long-term
effects of contamination. The tests using fish resemble the sur-
vival, growth, and teratogenicity tests for freshwater fish, with the
appropriate adjustments of test conditions and species substitu-
tions. All of these tests are described in Reference 7.
The inland silverside (Menidia beryllina) larval survival
and growth test is a static-renewal test that lasts for seven days and
measures the survival and increase in weight of inland silverside
larvae.
The sheepshead minnow (Cyprinodon variegatus) larval
survival and growth test uses the static-renewal design and lasts
for seven days, monitoring the survival of test organisms and their
increase in weight
The sheepshead minnow (Cyprinodon variegatus) embryo-
larval survival and teratogenicity test assesses the chronic
toxicity of a sample to minnows, beginning as embryos and
extending to the larval stage. The test uses the static-renewal
design and lasts for nine days, recording both the survival of the
fish and any development of terata.
The mysid (Mysidopsis bahia) survival, growth, and fe-
cundity test evaluates the chronic toxicity of a sample to mysid
shrimp, beginning as juveniles and extending through their sexua
3 Biosiimulation refers to excessive growth of algae, a condition not
likely to occur at Super fund sites.
March 1994 • Vol. 2. No. 2
ECO Update
-------
maturation. The test uses the static-renewal design and lasts for
seven days, monitoring survival, weight gain, and egg production.
The sea urchin (Arbacia punctulata) fertilization test evalu-
ates toxicity to the eggs and sperm of Arbacia punctulata. The test
exposes dilute sperm suspensions to a water sample for one hour.
Then eggs are added, and 20 minutes later the test terminates. The
technician then calculates the percent fertilization.
The algal (Champia parvula) sexual reproduction test uses
a static design and lasts five to seven days, exposing a mixture of
male and female algae to the sample for two days and then
transferring them to a nontoxic medium. At the end of the test, the
test organisms are scored for their production of cystocarps, the
structures that result from fertilization.
Sediment Toxicity Tests
Because of the paucity of data coiicerning sediment toxicity,
tests designed specifical 1 y to evaluate the toxicity of sediments are
in their early stages of development. Currently, protocols exist for
chronic toxicity tests only. As research continues, new tests should
become available to investigators.
For additional information on sediment toxicity tests, consult
ASTM's Standard Guide for Conducting Sediment Toxicity Tests
with Freshwater Invertebrates (Reference 4). In addition, Proto-
cols for Short Term Toxicity Screening of Hazardous Waste Sites
by Greene etal. (Reference 5) describes a lettuce seed germination
assay and a lettuce root elongation assay that can be used to
measure the toxicity of elutriates.
Chronic Freshwater Sediment Toxicity Tests
The following tests assess the chronic toxicity of sediment
samples to three freshwater invertebrates. For these tests a layer of
water overlies the sediment sample. The design may either be static
or involve flow-through replacement of the overlying water. Test
duration varies with the objectives of the study but generally does not
extend beyond 30 days. These tests are described in Reference 2.
Hyalella azteca sediment toxicity tests evaluate sediment
toxicity to Hyalella azteca, an amphipod that swims in the water
column and burrows in the sediment surface. Short-term tests last
10 days or fewer and evaluate the survival, growth, and develop-
ment of the test organisms. Longer tests can last up to 30 days
allowing the evaluation of the effect of the sediment on reproduc-
tive behavior, sexual development, egg production, and the devel-
opment of offspring.
Chironomus tentans and Chironomus riparius sediment
toxicity tests evaluate sediment toxicity to midge larvae. The
larvae burrow into sediment to build a casing within which they
mature. Tests lasting 10 to 14 days evaluate the effect of exposure
on survival and growth. Longer tests assess the effects of toxicity
on development and reproduction.
Chronic Marine Sediment Toxicity Test
The ten-day static sediment toxicity test using marine and
estuarine amphipods measures the acute toxicity of marine
sediments to amphipods that burrow in the sediment. This test also
can evaluate sub-lethal effects, such as emergence from a highly
toxic sediment and the inability to re-burrow into clean sediment
at the termination of the assay. (See Reference 3.)
Terrestrial Toxicity Tests
Compared with aquatic toxicity tests, few protocols exist for
evaluating the toxicity of soils. However, several techniques
currently in development should soon be standardized, increasing
the number of options available.
Some investigators have tried to overcome the lack of stan-
dardized terrestrial toxicity tests by preparing elutriates and ana-
lyzing these by means of aquatic toxicity tests. However, this
approach does not account for the toxicity of contaminants that
remain sorbed to soil particles. On the other hand, analyzing
elutriates with aquatic toxicity tests can prove useful when explor-
ing the mobility of contaminants.
These tests are described in Reference 5.
The earthworm (Eisenia foetida) survival assay estimates
toxicity of soil or solid waste to earth vorms. The test uses the static
design and lasts 14 days, monitOiing the survival of the test
organisms. This assay usually involves the use of soil samples, but
can be conducted in sediment diluted with artificial soil. An
alternate test design—exposing earthworms to artificial soil mixed
with water samples or elutriate dilutions—makes this assay useful
in assessing water samples or elutriates.
The lettuce (Latuca saliva) seed germination assay em-
ploys a static design and lasts, as specified in the protocol, 120
hours (5 days). As in the earthworm test, the test can use sample soil
or sediment diluted with artificial soil, or artificial soil wetted with
a water sample or an elutriate of soil or sediment.
The lettuce (Latuca sativa) root elongation assay also uses
a static design and lasts, as specified in the protocol, 120 hours (5
days) This test monitors both seed germination and seedling
length. In this test, the technician places the seeds on pieces of filter
paper wetted with either a water sample, an elutriate sample, or a
sample dilution.
Microbial Toxicity Tests
Microbial toxicity tests assess toxic effects on the microbial
community and can serve as cost-effective and rapid screening
indicators. They are described in Reference 4.
The ATP-TOX system test measures a sample's effect on
bacterial growth. For this test, ba^ £ria are suspended in a water
sample or a soil or sediment elutriate. After several life cycles, a
technician estimates the density of bacterial growth using a method
that gives the test its name: since each bacterium has a fairly
constant concentration of the chemical compound adenosine triph-
osphate (ATP), measuring the ATP content of a suspension of
bacteria provides a reliable estimate of the bacterial population.
The Toxi-Chromotest measures the acute toxicity of a water
sample or soil/sediment elutriate to Escherichia coli, a bacterial
species that commonly inhabits the mammalian gut. Specifically,
the test monitors the activity of the enzyme beta-galactosidase,
which is inhibited by heavy metals. A modification of the Toxi-
Chromotest, the SOS chromotest, monitors genetic changes that
alter the expression of a gene associated with the beta-galactosi-
dase system.
The Microtox® test measures the toxicity of water samples
or elutriates to Photobacteriumphosphoreum, a species of bioiu-
minescent marine bacteria. Some contaminants inhibit the bacteria's
ECO Update
March 1994 • Vol. 2, No..
-------
i, decreasing the intensity of light emitted. Other con-
taminants stimulate the bacteria and cause an increase in
luminescence.
Conclusion
As discussed in the companion Bulletin to this document,
loxicity tests represent one set of tools that can be used to e val uate
possible adverse ecological effects at Superfund sites. To be
effective, these tests must be planned and evaluated carefully, in
the context of an overall ecological risk assessment designed to
meet specific objectives. Site managers are urged to consult with
their Regional BTAGs to ensure that tests appropriate to specific
circumstances are selected and that the tests are conducted in such
a manner as to be useful in supporting remedial decisions.
References
1. American Society for Testing and Materials (ASTM). 1992.
Annual Book of ASTM Standards: Water and Environmental
Technology, Vol. 11.04. American Society for Testing and
Materials, Philadelphia, PA. 1426 pp.
2. American Society for Testing and Materials (ASTM). 1992.
Standard Guide for Conducting Sediment Toxicity Tests with
Freshwater Invertebrates. American Society for Testing and
Materials, Philadelphia, PA. 23 pp.
3. American Society for Testing and Materials (ASTM). 1992.
Standard Guide for Conducting 10-day Static Sediment Tox-
icity Tests with Marine and Estuarine Amphipods. American
Society for Testing and Materials, Philadelphia, PA. 24 pp.
4. Bitton,G.,BJ.Dutka,andC.W.Hendricks. 1989. Chapter6,
Section 4 in Warren-Hicks, W., B.R. Parkhurst, and S.S.
Baker Jr., eds. Ecological Assessment of Hazardous Waste
Sites: AFieldandLaboratoryReference.EPA/6QO/3-89/Q\3.
Environmental Research Laboratory, Office of Research
Development, U.S. Environmental Protection Agei
Corvallis, OR.
5. Greene,J.C.,C.L.Bartels,WJ.Warren-Hicks,B.R.Parkhurst,
G.L. Linder, S.A. Peterson, and W.E. Miller. 1989. Protocols
for Short-Term Toxicity Screening ofHazardous Waste Sites.
EPA/600/3-88/029. Environmental Research Laboratory,
Office of Research and Development, U.S. Environmental
Protection Agency, Corvallis, OR.
6. Weber, C.I. 1991. Methodsfor Measuring the Acute Toxicity
of Effluents and Receiving Waters to Freshwater and Marine
Organisms. 4th edition. EPA/600/4-90/027. Environmental
Monitoring Systems Laboratory, Off-^e if Research and
Development, U.S. Environmental Protection Agency, Cincin-
nati, OH.
7. Weber, C.I., W.I. Homing, DJ. Claim, T.W. Neiheisel, P.A.
Lewis, E.L Robinson, J. Menkedick, and F. Kessler. 1988.
Short-term Methods for Estimating the Chronic Toxicity of
Effluents and Receiving Waters to Marine and Estuarine
Organisms. EPA/600/4-87/028. Environmental Monitoring
and S upport Laboratory, Office of Research and Development,
U.S. Environmental Protection Agency, Cincinnati, OH.
8. Weber, C.I., W.H. Peltier, T.J. Norberg-King, W.B. Homing
II, F. Kessler, and J. Menkedick. 1989. Short-term Mt
for Estimating the Chronic Toxicity of Effluents andReca
ing Waters to Freshwater Organisms. 2nd edition. EPA/600/
4-89/001. Environmental Monitoring Systems Laboratory,
Office of Research and Development, U.S. Environmental
Protection Agency, Cincinnati, OH.
March 1994-Vol. 2, No. 2
ECO Update
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vvEPA
United States
Environmental Protection
Agency
Office of
Solid Waste and
Emergency Response
Publication 9345.0-OE
March 1994
ECO Update
Office of Emergency and Remedial Response
Hazardous Site Evaluation Division (5204G)
Intermittent Bulletin
Volume 2, Number 3
Field Studies for Ecological Ris'<
Assessment
Ecological risk assessments of Superfund sites evaluate
the actual or potential effects of site contaminants on plants and
animals and assess the need for remediation, including consid-
ering remedial alternatives and evaluating ecological effects of
remediation. Such ecological risk assessments make use of a
variety of desktop, laboratory, and field approaches, which may
include chemical analyses of media, loxicity testing, literature
searches, evaluation of the condition of organisms, and ecologi-
cal field studies. As the name implies, ecological field studies
are investigations that take place in the actual area under
scrutiny, focusing on the site's habitats and biota1 (resident
organisms) and comparing them with unimpacted conditions.
The ecological risk assessment of a Superfund site nearly
always requires some type of field study. At a minimum, some
field study is necessary- in order to identify organisms and
habitats2 that may be at risk. By themselves, hazard indices
based on literature values rarely prove adequate for character-
izing ecological effects.
Rather than studying individual organisms, field studies
generally focus on populations or communities. Populations
are groups of organisms belonging to the same species and
inhabiting a contiguous area. Communities consist of popula-
tions of different species living together. For example, a forest
community consists of the plants, animals, and micro-organ-
isms found in a forest. A community also can be a more
restricted group of organisms. Within the forest, the soil com-
munity consists of only those organisms living in, or in close
association with, the soil. Less frequently, a field study evalu-
ates an ecosystem, which consists of both the organisms and the
nonliving components of a specific, limited area.3 In the case of
a forest, the ecosystem includes the soils, rocks, streams, and
springs as well as the resident organisms that make up the forest
community.
Which sites warrant a detailed field study? At many sites,
the existing information indicates a significant likelihood of
present or future adverse impact but is insufficient to support
remedial decision making. At such sites, field studies can
identify actually or potentially exposed organisms, exposure
routes, ecological effects, and also the potential of the site to
support biota. In the initial phase of an ecological risk assess-
ment, a field study can take the form of a site reconnaissance
visit by an ecologist. The ecologist can record the site's habitats
and many of its species and also note any obvious adverse
ecological effects. If a site warrants further field study, a more
'The first lime that a technical term appears, it is bolded and
either defined in the text or in a footnote.
2 A habitat is the place that a sj. ,cies naturally inhabits.
3 Although ecologists often use this term to include much larger
resources, this definition gives the word dimensions usable at a
Superfund site.
IN THIS BULLETIN
The Organisms in a Field Study 3
Elements in the Design of a Field Study 5
Catalogue of Field Methods 9
Field Studies: Their Contribution 10
ECO Update is aBulletin series on ecological risk assessment of Superfund sites. TheseBulletins serve as supplements to Risk Assessment Guidance
for Superfund, Volume II: Environmental Evaluation Manual (EPA/540-1-89/001). The information presented is intended to provide technical
information to EPA and other government employees. It does not constitute rulemaking by the Agency, and may not be relied on to create a
substantive or procedural right enforceable by any other person. The Government may take action that is at variance with these Bulletins.
-------
->sivf - on during the analysis phase can help to provide
evidence of a link between a site's contaminants and an adverse
effect. As Table 1 shows, field studies can contribute information
at different stages of the ecological risk assessment and can assist
with each of the assessment's three components: problem formu-
lation, analysis, and risk characterization.4
'The specific role of field study in an ecological risk assess-
ment varies with the site. Site managers5 should consult with the
B iological Technical Assistance Group (BT AG) in their Region to
determine the best approach to each site.6 This consultation should
occur at the earliest possible stage of site investigation. The BTAG
may suggest other methods—in addition to, or instead of, tech-
niques discussed in this document—that are especially appropriate
for a particular site.
This Bulletin provides site managers with an overview of
field study options. Four main sections follow this Introduction.
The first considers the organisms, which are the major focus of
most field studies, and the second describes the remaining el
ments in the design of a field study. The third section presents
catalogue of common field study methods, while the fourth section
summarizes the contributions that field study can make to an
ecological risk assessment.
This Bulletin is intended only as a quick reference for site
managers, not as a comprehensive review of field methods or of the
ecological attributes evaluated using these methods. Those who
want to examine the subject in greater depth should consult the list
of references at the end of the Bulletin and also the list of additional
resources available from the federal government.
Table 1. Field Study Contributions to Ecological Risk Assessments
Task
Problem
Formulation
Analysis
Risk
Characterization
Site Reconnaissance Visit
Identify ecological
components potentially
exposed to contaminants.
Identify ecological
components likely to be
exposed to contaminants.
Identify readily apparent
effects.
Develop hypothesesof
relationship between
exposure and effect1?
Intensive Field Study
Identify specific ecological
components and the
exposure pathways for
populations and
communities.
Describe populations and
community attributes
with respect to exposure.
Quantify exposure of specific
ecological components.
Quantify effects on
specific ecological components.
Characterize and document links
between exposure and effects.
Quantify relationship
between exposure and
effects.
* In preparing this Bulletin, every effort was made to use the terminology found in the Framework for Ecological Risk Assessment (U.S. EPA. 1992.
Office of Research and Development, Risk Assessment Forum. EPA/630/R-92/001. Washington, D.C.). The three phases listed in the text are equivalent
to the four components of an ecological risk assessment described in "Ecological Assessment of Superfund Sites: An Overview" (ECO Update Vol. 1,
No. 2). The Framework's analysis phase corresponds to the "Overview's" exposure assessment and the ecological effects assessment phases.
5 Site managers include both remedial project managers and cm-scene coordinators.
* These groups are sometimes known by different names, depending on the Region. Readers should check with the appropriate Superfund
for the name of the BTAG coordinator or other sources of technical assistance in their Region. A more complete description of BTAG structure and function
is available in "The Role of BTAGs in Ecological Assessment" (ECO Update Vol. 1, No. 1).
March 1994-Vol. 2. No. 3
ECO Update
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The Organisms in a Field Study
Although a large number of species can inhabit a site, an
ecological risk assessment of a Superf und site concerns itself only
with those that are actually or potentially adversely affected by site
contamination or that can serve as surrogates for such species.
Such organisms are among a site's ecological components. Eco-
logical components are populations, communities, habitats, or
ecosystems actually or potentially affected by sitecontamination.A
field survey conducted as part of a reconnaissance visit can help to
identify the potentially affected organisms at a site. Some factors
to consider in making this identification include which media (e.g.,
soil, surface water, ground water) have become contaminated, the
site's contaminants, their environmental concentrations, and their
bioavailability.7
General Considerations in Selecting
Organisms for Study
Most sites have a large number of resident species, making it
necessary for the investigator* to focus on a limited number of
these for detailed study. A variety of site-specific factors—includ-
ing the size of the site and the types of habitats that have become
contaminated—contribute to making this selection. In their role as
protectors of natural resources, trustees also can influence the
selection of organisms for study.
Species-specific factors also enter into the selection. These
include:
• Intensity of exposure. Species vary in the intensity of their
contact with contaminated media. For example, earthworms
and other invertebrates inhabiting a contaminated medium
receive longer and more intense exposures than wider-rang-
ing invertebrates such as butterflies. Some animals have
limited mobility early in their life cycle—as eggs, larvae, or
nestlings, for example—so have greater exposure than older
animals.
• Relative sensitivity to contaminants. Evaluation of a highly
sensitive species can bring about de facto consideration and
protection of other species inhabiting the site. However, at a
site with a complex mixture of contaminants, the investigator
may be unable to identify one sensitive species that is most
appropriate for study.
• Ecological function, along with significance of a species'
contribution to this function. An investigator may select a
species for study based on its ecological function. For ex-
ample, at a site with contaminated surface water, the investi-
gator may choose to study algae as the aquatic community's
primary producers.9 The investigator may specifically fo-
cus on those algal species that make a large contribution to
this function.
• Time spent on-site. To qualify for further study, a species
should inhabit the site during either a considerable portion or
a critical stage of its life cycle.
• Ease or difficulty of conducting field studies with the organ-
isms. A field study that requires capturing birds is resource-
intensive, and unlikely to occur at a typical Superf und assess-
ment. Where fish-eating birds are at risk because
bioaccumulating substances have contaminated the surface
water or aquatic organisms, the investigator might choose
instead to focus primarily on the fish that the birds eat or to stud;
a mammal or reptile with feeding habits similar to the birds.
• Appropriateness of surrogate species. In the case of a siti
with an endangered or threatened species, the investigato
may elect to study a surrogate species with similar exposure
Surrogate species offer the advantage of sampling and analy
sis options that cannot be employed with threatened o
endangered species. However, in selecting a surrogate spe
cies, the investigator should identify one that resembles th
site species in behavior, feeding, and physiological respons
to the contaminants of concern. The best choice for a surro
gate is not necessarily the one most closely related to the sit
species.
• Other recognized values. At some sites the investigator ma
want to consider a species because of other values associate
with it, such as economic or recreational value.
Based on the above considerations, the investigator generall
selects no more than a few species as subjects of the field stud)
However, an investigator can choose to study a community. Fc
example, at a lake with contaminated water and sediment th
investigator can study the benthic community that lives in assocui
Although a large number of species
can inhabit a site, an ecological risk
assessment of a Superfund site con-
cerns itself only with those that are
actually or potentially adversely affected
by site contamination or that can serve
as surrogates for such species.
tion with the lake's bottom. When selecting a community as a
ecological component, the investigator needs to ascertain that th
study includes populations representing multiple trophic levels.1
At some Superfund sites, investigators have selected a we
land habitat as the ecological component for further study. Such
choice can prove more protective of the environment since th
investigator can document a variety of adverse effects on th
7 Bioavailability is the occurrence of a contaminant in a form th
organisms can take up.
'The term "investigator" refers to the individual charged wi
responsibility for designing and/or carrying out any pan of an ecologic
risk assessment. Investigators can include government scientists, contrai
tors, or university scientists. However, the site manager (remedial proje
manager or on-scene coordinator) retains ultimate responsibility for it
quality of the ecological risk assessment
9 A primary producer is an organism, such as an alga or a terrestri
plant, that converts the energy from sunlight to chemical energy.
10 A trophic level is a stage in the flow of food from one populatic
to another. For example, as primary producers, plants occupy the fir
trophic level, and grazing organisms occupy the second trophic level.
ECO Update
March 1994-Vol. 2, No.
-------
\bif-if ^-athor than having to demonstrate significant impact to only
one 01 a few species. Studying a habitat becomes especially
important when one or more of the remedies under consideration
could adversely affect the habitat. However, designating a habitat
as the ecological component can prove costly, depending upon
how the ecological risk assessment delineates the habitat.
To extend these general guidelines for selecting ecological
components, the following sections consider different kinds of
organisms that inhabit either aquatic or terrestrial environments
and detail how each can increase an investigator's knowledge of
the ecological conditions at the site.
Aquatic Organisms
At a site where contaminated surface water is a medium of
concern, field studies can focus on periphyton, plankton, benthic
macroinvertebrates, or fish. Periphyton are microscopic algae
that grow on sediment stems and leaves of roofd water vegeta-
tion, and other surface that project above the bo .dm of a body of
water. Studying periphyton provides information about primary
producers in an aquatic environment. These organisms also in-
clude many species useful in assessing the cause, extent, and
magnitude of contaminant problems.
Plankton are microscopic organisms that float or swim
weakly in the water column. Plankton include algae, protozoa, and
small crustaceans. Planktonic algae are called phytoplankton,
and the protozoa and crustaceans in plankton are referred to as
zooplankton. Because plankton include primary producers, which
supply food for larger animals and also increase the amount of
oxygen dissolved in water, these organisms make an important
contribution to the aquatic community. Like periphyton, plankton
include species that are sensitive indicators of ecological injury
resulting from contamination or enrichment of water bodies.
As defined by EPA, benthic macroinvertebrates are inver-
tebrate animals that live in or near the bottom of a body of water and
that will not pass through a U.S. Standard No. 30 sieve, which has
0.595 mm openings. Such organisms occur in gravel, sediments,
on submerged logs and debris, on pilings and pipes, and even on
filamentous algae. Freshwater benthic macroinvertebrates include
insects, worms, freshwater clams, snails, and crustaceans. The -
benthic macroinvertebrate communities of marine and estuarine
environments include worms, clams, mussels, scallops, oysters,
snails, crustaceans, sea anemones, sponges, starfish, sea urchins,
sand dollars, and sea cucumbers. When water becomes contami-
nated, some of the contaminants migrate to the sediment and
accumulate there. Field studies of benthic macroinvertebrates can
indicate the degree to which sediment contamination can ad-
versely affect biota. In addition, the composition and diversity of
benthic macroinvertebrate communities can indicate the overall
well-being of the aquatic ecosystem.
Because fish occupy a range of trophic levels, they serve as
useful indicators of community-level effects. The relative ease of
identifying most juvenile and adult forms makes fish particularly
convenient subjects for field study. In addition, field study meth-
ods for fish are relatively simple and inexpensive. In selecting a
species for sampling, the investigator will want to consider its
characteristic home range. For a species that spends little time on-
site, a field study may not be able to establish whether any adverse
effects result from exposure to site-associated contaminants.
Semi-aquatic and Terrestrial Animals
Semi-aquatic and terrestrial animals—including insects, other
invertebrates, and vertebrates—can all provide useful information
about ecological effects associated with the site. Soil fauna,
organisms most intimately associated with this medium, incl
many species that perform important functions in terrestrial eco-
systems. For example, earthworms aerate the soil. Other soil-
dwellers—such as some small insects, soil mites, and certain
nematodes (a kind of worm), break down organic wastes and dead
organisms—releasing the elements and compounds they contain
and making these available to living organisms. Both soil aeration
and organic decomposition support the growth of terrestrial plants.
Consequently, plants can suffer impact if soil fauna are affected.
Insects' small size and their large numbers make them conve-
nient subjects of study. Further, a site generally has a large number
of species. Because these species occupy a variety of microhabitats
and also differ in their behaviors, the investir^lo can measure a
range of effects. For example, because insects include species at
different trophic levels, a field study can assess the potential for
biomagnification" of a site's contaminants.
Field studies focusing on such vertebrates as amphibians,
reptiles, and mammals can contribute to a site's ecological assess-
ment. Depending on their trophic level, these vertebrates may
ingest contaminants as a result of consuming contaminated plants,
other terrestrial animals, or fish. Burrowing animals, such as voles,
can show greater ecological effects from contaminated soil than
animals that have less intimate contact with the soil. Where
investigators at Superfund sites decide to study terrestrial verte-
brates, they generally choose small species, which are likely t^^
range over a smaller area than larger species. As a result, trfll
smaller species tend to spend more of their time on the site, making
it easier to estimate exposure.
Field studies of birds present certain difficulties at a
Superfund site. These organisms can range far off-site, making
it difficult for a field study to establish whether an adverse
ecological effect results from exposure to site-associated con-
taminants. In addition, bird studies can prove especially resource-
intensive. However, at a large site or a site with a complicated
contaminant picture, the investigator and the BTAG may decide
that avian field studies are worth the effort. For example, many
sites have large populations of waterfowl that can potentially
suffer adverse effects from site contaminants.
Terrestrial Vegetation
When a site has contaminants associated with the soil, field
study can focus on terrestrial vegetation. In particular, investiga-
tors may want to conduct field studies of vegetation at Superfund
sites where plants show signs of stress, such as stunted growth or
yellowing, or where pollution-tolerant species are abundant. Since
plants are the primary producers in terrestrial environments, an
ecological impact to vegetation can affect other terrestrial biota.
" Biomagnification is the increasing concentration of a
bioaccumulaling contaminant as it passes up a food chain or a food web.
A food chain is a series of organisms that sequentially feed on one anoth
For example, mice eat seeds and are in turn eaten by owls. A food
which is a group of interrelated food chains, takes into account a species
participation in multiple food chains. For example, birds, insects, and
other mammals also eat seeds, and cats, as well as owls, prey on mice.
March 1994-Vol. 2, No. 3
ECO Update
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Elements in the Design
of a Field Study
As with any study, an ecological field study has several
elements. In addition to selection of the organisms, the elements of
a field study encompass the study's objectives, a reference site,
endpoints, methods, level of effort, sample design, quality assur-
ance/quality control standards, and the statistical analysis of the
data. When the investigator carefully crafts each of these elements,
the resulting study should achieve its objectives and should further
the overall ecological risk assessment of the Superfund site.
Under-developing any of these elements can weaken the study's
results and adversely affect the results of the overall assessment.
Objectives
To ensure that the study will have clear direction, the inves-
tigator needs to establish study objec ' res that address ecological
concerns for that site. The objectives should ensure that the field
study supports the over-all objectives of an ecological risk assess-
ment for a Superfund site. These objectives are (1) to determine
whether site contamination poses a current or potential threat of
adverse ecological effects; (2) if a threat does exist, to decide
whether remediation is required; and (3) if remediation is required,
to set cleanup levels.
Investigators will find that study objectives help to indicate
the appropriate level of effort. In an initial field study to identify
ecological components, for instance, an investigator might find
that a qualitative survey method would achieve the study's objec-
tive. The later study of adverse effects to a population might
require a more resource-intensive approach, such as semi-quanti-
tative or quantitative sampling to estimate population sizes or
capture of organisms and transport to a laboratory for biochemical
analysis.
Although the specific objectives for a fielu study will vary
both with the site and its stage in the ecological risk assessment
process, investigators should keep in mind that a field study
performed as part of a Superfund site's ecological risk assessment
is not a research project. Generally, a snapshot of site characteris-
tics can provide the needed information.
In addition to stating the purpose of a field study, the objec-
tives also should indicate whether the field study is occurring in
conjunction with another type of study, such as a toxicity assess-
ment. In such a case, the two studies have a shared goal: to
determine whether adverse ecological effects correlate with toxic-
ity. To meet this goal, the studies' objectives should emphasize the
need for integrating sampling plans and coordinating the collec-
tion of data. When sampling for coordinated studies occurs at the
same time and location, and with similar data quality objectives
and levels of precision, the investigator can more convincingly
compare results.
Reference Site
A reference site is a location that closely resembles the
Superfund site in terrain, hydrologic regime, soil types, vegetation,
and wildlife. A well-chosen reference site provides background
conditions, allowing the investigator to draw conclusions about the
ecological effects of contaminants on the Superfund site. The more
closely the reference site resembles the Superfund site, the more
valid will be the conclusions based on comparisons of the two. It
some cases, no single reference site adequately approximates thi
S uperf und site. In such a case, the investigator may need to identify
multiple reference sites.
The investigator should try to locate a reference site as closi
as possible to the Superfund site so that it will accurately reflect th
conditions prevailing at the Superfund site. Yet the reference sit
should lie at a great enough distance from the Superfund site to b
outside its sphere of influence and relatively contaminant-free. Fo
example, an upstream location often can provide appropriat
reference site conditions for a site with contaminated surfac
water. A woodland site used as a reference site needs to lie at a gres
A field study performed as part of
a Superfund site's ecological risk
assessment is not a research project.
enough distance from the Superfund site that ranges of organism
will not include both sites.Failure to choose appropriate referenc
sites can result in inaccurate conclusions. For example, if th
surface water at the Superfund site consists largely of soft-bo
tomed pools, then an area having fast-running streams with grave
bottoms will not provide an appropriate comparison. Difference
in species composition and other features at the two sites will, i
least in part, reflect their very different aquatic habitats rather tha
contamination at the Superfund site.
In the absence of suitable reference sites, an investigator ma
need to turn to historical information about the site and/or a larg
database in order to make a comparison between site condition
and conditions in an uncontaminated area. If this approach be
comes necessary, the investigator needs to choose a data sourc
that reflects the site's geologic, hydrologic, and ecological traits £
closely as possible. In making this selection, the investigator ca
obtain advice and suggestions from the BTAG.
Endpoints
The identification of endpoints, which are ecological charai
teristics that may be adversely affected by site contaminants,
essential to a successful ecological risk assessment as a whole ar
also to each of the studies that make up this assessment Ecologic
risk assessors have found it useful to recognize two levels <
endpoints, assessment and measurement endpoints. An asses
ment endpoint is an explicit expression of the environment
characteristic that is to be protected (24,29)." At a Superfund si
an assessment endpoint is an endpoint that may drive remedi
decision making. Determining potential contaminants of concei
and potential ecological components and developing a conceptu
model of a site's contaminant situation generally indicates whic
ecological traits are assessment endpoints at a particular site.
12 Numbers in parentheses refer to references listed at the end oft]
Bulletin.
ECO Update
March 1994- Vol.2.No.
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A measurement endpoint is an ecological trait that is closely
related to an assessment endpoint and that is, in addition, readily
measurable. A measurement endpoint, then, is a response that can
approximate or represent an assessment endpoint which is not
amenable to direct measurement. A site's ecological components
and assessment endpoints drive the selection of the measurement
endpoint(s). (See Figure 1.) For example, at a site where lead is a
contaminant of concern and which has resident species sensitive to
lead, the investigator may identify lead poisoning as an assessment
endpoint and one or more lead-sensitive species as ecological
components. The investigator's choices of measurement end-
points are then limited to accepted ways of measuring the presence
of lead in organisms or its effects on them.
Table 2 summarizes measurement endpoints for field studies.
Although a field study can focus on one population, an entire
Figure 1. The Relationship Between
Ecological Components,
Assessment Endpoints, and
Measurement Endpoints
in designing a field study, the ecological
components and assessment endpoints
generally drive the selection of measure-
ment endpoints.
Ecological
Component
Measurement
Endpoint
Assessment
Endpoint
community, or even two or three communities, as both Table 2 and
the following discussion indicate, measurement endpoints for field
studies are much more than simply "head counts."
Biomass, the total weight of individuals, can be a measure-
ment endpoint for both populations and communities. An investi-
gator may measure biomass directly by weighing collections of
small organisms or, for larger organisms, by weighing individuals
and summing their weights. Alternatively, he or she may use an
indirect method, such as applying length-to-weight regressions to
data detailing the number and length of individuals in a population,
an especially common approach for fishes.
Productivity, the rate of increase, is another measurement
endpoint that can apply to both populations and communities. For
plants, the rate of increase in biomass indicates productivity. For
many animals, investigators take the rate of increase in numbers as
the measure of productivity. Because productivity is a rate, mea-
surements or estimates must occur at least twice during
growing season. However, investigators can infer productivity b
conducting seed or egg counts or by studying the age structure of
a population. At Superfund sites, investigators can infer relative
producu'vi'y by comparing data from the Superfund site and the
reference site(s).
A common measurement endpoint for terrestrial plant popu-
lations is cover, which is the percentage of ground area that lies
beneath the canopy (uppermost branches) of a tree or shrub
species. In evaluating a stand of trees, an investigator can instead
measure basal area, which is the sum of the cross-sectional area
of the trees' trunks.
Some measurement endpoints relate specifically to commu-
rity parameters. Species richness is the num >er of species in a
community. Species density refers to the number of individuals of
a given species per unit area, while relative abundance is the
number of individuals in a particular species compared to the total
number of individuals. Dominance, in the sense of commonness
at a site, describes a species that occurs in high abundance, as
indicated largely by species density. Diversity relates the abun-
dance of individuals in one taxon (level of classification) to the
total abundance of individuals in all other taxa. Evenness mea-
sures how evenly distributed individuals are among thecommunity's
taxa. Guild structure, which refers to the different types of
feeding groups in a community, also can be used to evaluate
community structure.13 A number of similarity and differenc
indices14 can compare community structure at Superfund
reference sites.
Another community-level measurement endpoint concerns
indicator species, which are species whose presence, absence, or
population density helps to indicate whether the environment is
contaminated. Some species are associated with thriving commu-
nities, so either absence or a reduced population can indicate an
ecologically disturbed environment. For example, the larval stage
of insects in the orders Ephemeroptera (mayflies), Plecoptera
(stoneflies), and Trichoptera (caddisflies), referred to collectively
as the "EPTs," show sensitivity to metals and other inorganic
contaminants. Reduced populations of EPTs, then, can indicate
toxic levels of metals or other inorganics in a stream. Conversely,
some species occur in association with a disturbed habitat, where
they dominate or kill native species weakened by exposure to
contaminants. For example, such plant species as Phragmites and
cattails (Typha) characteristically grow abundantly in disturbed
wetlands. Consequently, dense growth of Phragmites or cattails
indicates that a wetland may have suffered ecological stress.
" Guilds, also called functional feeding groups, are groups of
animals occupying the same trophic level and feeding either in the same
way or in the same location. For example, among terrestrial plant-ea
there are five guilds: stem-eaters, root-eaters, leaf-eaters, bud-eaters,
nectar-sippers.
M An index is a single number that incorporates information from a
class of data.
March 1994-Vol. 2, No. 3
ECO Update
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In conducting field studies, the level of effort vanes with the
sampling method chosen: qualitative, semi-quantitative, or quan-
ive (17). Qualitative sampling, which has as its goal to observe
ple as many taxa as possible in the available time, requires
least effort Qualitative sampling attempts to sample all habi-
tats, using several collection methods at each sampling station.
Such an approach can prove useful for a site reconnaissance visit,
with the objective of identifying potentially exposed ecological
components and readily apparent effects.
Rapid Bioassessment Protocol II is an example of a semi-
quantitative, or intermediate-level, sampling method for benthic
macroinvertebrates inhabiting flowing waters (27). This approach
offers a time-saving and cost-effective means of obtaining infor-
mation about benthic macroinvertebrates. In this approach, the
field team uses a net to collect organisms from two approximately
one-square-meter areas, one in a fast-flowing part of the stream
and the other in a slo^ :r-flowing area. The on "I'sms are then
enumerated and classiued only to family level, which requires less
time than classification to genus or species. A sub-sample of 100
organisms is then classified according to guild. An additional
sample is collected from an area with coarse paniculate organic
matter, such as a leafpack or an area near the shore. The organisms
in this sample are classified simply as shredders or non-shredders.
Quantitative sampling uses methods that sample a unit area or
volume of habitat Generally, these methods are applied to ran-
domly selected sampling units. As with semi-quantitative sam-
pling, the organisms collected are counted and classified.
In deciding on level of effort, investigators should be aware
limited sampling efforts can provide enough data for an
uate ecological risk assessment of a Superfund site. It is true
that differences in life cycle characteristics and diurnal effects do
prevent limited sampling from providing a comprehensive esti-
mate of all species. However, if field studies at the site sample
enough biota, these kinds of variations will have minimal effect on
the overall assessment.
Sampling Plan
A sampling plan for a field study indicates the number of
sampling points, the number of replicates for each sampling point,
the method for determining sampling locations, holding times for
samples, and any sample preparation required for laboratory
analysis. In makinq these decisions for an ecological field study,
the investigator needs to consider the study objectives, the level of
effort, the site's size, the ecological component(s), the measure-
ment endpoint, the method, the statistical method of analyzing
data, and the available resources. For example, the approach to
statistical analysis will affect sampling size. If the field study is one
of a group of coordinated studies, then the investigator also needs
to consider whether a particular sampling method can apply to all
the studies in the group.
In general, sampling locations can be selected either non-
randomly or randomly. Qualitative and semi-quantitative surveys
make use of non-random sampling, taking into account the habitat
« mobility of the organisms and the location of contaminant "hot
ts." For quantitative sampling, investigators generally use
random sampling methods.
When the investigator has decided on the number of sam-
pling locations and the method of selecting them, he or she must
also decide how many replicate samples to collect per site. Both the
study objectives and the data quality objectives (discussed below)
influence this decision. While natural variability makes replicate
sampling desirable, for some field studies the sampling plan
cannot specify a fixed number of replicates. For example, field
biologists have no control over trapping success.
Quality Assurance/Quality Control (QA/QC)
Standards
Quality assurance and quality control standards are an essen-
tial element in the study plan. Included among the QA/QC consid-
erations are the data quality objectives (DQOs). These are
statements that define the level of uncertainty that the investigator
is willing to accept in environmental data used to support a
remedial decision. DQOs address the purpose and use of the data,
the resource constraints on data collection, and any calculations
based on the data. In particular, DQOs help invsti; ators to decide
how many samples and replicates to collect in order to limit
uncertainty to an acceptable level.
DQOs also guide decisions about the level of detail necessary
for the study. For example, in field studies involving certain groups
of organisms, such as insects, DQOs establish the level to which
the investigation should take the identification of organisms.
Identification to the level of family or genus requires less expertise
and time than identification to the level of species. However, the
DQOs may require identification to the species level to obtain
detailed enough information about the site's ecological condition.
In addition to defining acceptable uncertainty, QA/QC stan-
dards address other concerns:
• Reference sites. As discussed earlier, the investigator should
achieve a careful match between the Superfund site and one
or more reference sites.
• Accurate identification of organisms. The investigator must
identify organisms accurately. A common means of ensuring
the accuracy of identification involves having the classifica-
tion of a subset of organisms verified by independent experts.
• Adherence to sampling plan. Field biologists must adhere
closely to the sampling plan in order to collect valid data.
Consequently, the study's design will need to incorporate
methods for checking how precisely personnel have followed
the sampling plan. For example, QA/QC standards may
require field biologists to maintain field notebooks and sub-
mit copies of these. Chain of custody documents provide
another means of tracking sample collection, transfer, and
analysis.
• Contractor. The contractor selected must have personnel
with the expertise needed to perform the particular type of
field study and interpret the data. In addition, the contractor
must have the necessary equipment and personnel skilled in
its use and maintenance.
Statistical Analysis of Field Data
In performing statistical analyses of field data from Superfund
sites, two issues require special consideration: lack of randomness
and use of indices.
Lack of Randomness. Neither the Superfund site nor the
reference site is selected randomly. As a result of this lack of
randomness, the investigator must use one of the following ap-
March 1994 • Vol. 2, No. 3
ECO Update
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Methods
Field studies gather information about the site by observing
organisms, noting signs of an animal species' presence, or collect-
ing organisms for further study. With respect to methods, the work
plan for a site should include detailed instructions for sampling
organisms and collecting the relevant data. This data may include
such physical measurements as the temperature at a sampling site.
Proper methodology ensures that the data collected can be ana-
lyzed and results interpreted.
Observation indicates whether a species occurs at the site. For
vegetation and for animals with limited mobility, the observer also
can note the condition of the organisms. Investigators need to keep
in mind that for more mobile animals, observation indicates only
whether the species occurs at the site, not what percentage of time
it spends there. Observing organisms can be as straightforward as
walking the site or can involve the use of specialized equipment,
as in remote sensing of terrestrial vegetation. Remote sensing by
such means as infrared or multispectral photography can prove an
effective way of detecting stressed vegetation at a large site.
The signs of an animal's presence include scat (feces);
burrows, nests, or dens; cast-off larval cases or cocoons; tracks;
and carcasses. Characteristic sounds, such as bird songs, also can
reveal an animal's presence and sometimes provide limited infor-
mation about relative abundance. Like direct observation of resi-
dent organisms, observation of animal sign indicates only whether
a species occurs at the site, not the percentage of time it spends
there.
Methods of collecting samples for further study vary with the
kind of organism being studied. A field worker can catch a fish in a
net, capture a mouse in a trap, or sieve organisms from a soil or
sediment sample. Depending on the species and objectives, once the
investigator has collected the organisms, he or she may make direct
observations and then release them. Alternatively, the investigator
may retain the organisms for further study, such as analyzing tissues
for their contaminant content or examining them microscopically
for indications of contaminant-related abnormalities.
From among the wide variety of available field metric
those used at a Superfund site should provide data at a reason*
cost and within a reasonable timeframe for that site. Th
be readily reproducible, reliable, and relevant to the
STAG can assist investigators in selecting methods approprial
a site. In choosing a method, investigators also need to be av
that they should obtain permission from federal and state fish
wildlife agencies before collecting vertebrates. Some states ,
require permits for collecting certain other organisms.
At sites in the nation's temperate areas, investigators nee
coordinate site studies with seasons. Floristics surveys andph
synthetic measurements must be conducted during the grov
season. Surveying a migratory population, such as most
species, will require coordination with the season. In addil
natality studies should occur during the warm months, when r
animal species produce young.
The final section of this Bulletin provides additional infor
tion about techniques available for field studies of different t]
of populations and communities.
Level of Effort
A site's characteristics, its contaminant picture, and a ;
posed field study's objectives together indicate the level of el
appropriate to carrying out the study. For example, an objectiv
identify potentially affected animal species at a small site with
habitats will require a lower level of effort than one that spec
the evaluation of community structure at a large site with sev
habitats. The number and nature of ecological componj
endpoints specified by the objectives also may affect;
level of effort. As the number of ecological components"!
assessment and measurement endpoints increases, the leve
effort generally will increase. Additionally, some organisms
more difficult to observe or sample than others, and some mei:
ments are more difficult to make. For example, collecting in.
usually entails less effort than collecting fish.
»ne^^
nts an
Type
Measurement Endpoints
for Populations
Table 2. Measurement Endpoints In Field Studies
Measurement Endpoint
Biomass
Productivity
Cover (terrestrial vegetation)
Basal area (terrestrial vegetation)
Measurement
Endpoints for Communities
Biomass
Productivity and Respiration
(aquatic communities)
Species richness
Species density
Relative abundance
Dominance
Diversity
Evenness
Similarity/difference between Superfund site and reference site
Similarity/difference in guild structure between Superfund site and reference si
Presence, absence, or population density of indicator species
ECO Update
March 1994'Vol. 2,1
-------
proaches in statistically analyzing differences between the
Superfund site and the reference site:
• The investigator selects sampling stations randomly at both
the Superfund site and the reference site(s), and then tests the
hypothesis that observed differences between these stations
result from conditions at the stations in the Superfund site.
• The investigator tests the hypothesis that the reference site(s)
and the Superfund site differ. If such a difference exists, the
investigator then employs nonstatistical methods to evaluate
whether contamination at the Superfund site causes this
difference.
Use of Indices. A field study can generate a volume of data too
large to be analyzed efficiently. In such a case, reducing classes of
data to a single number, called an index, simplifies the analysis.
Some of the community traits discussed earlier, including even-
ness and diversity, are examples of indices calculated from taxo-
nomic data. Indices also include bioti<~ mdices, which examine the
environmental tolerances or requirements of particular species or
groups of species.
While indices can make field data more manageable, inves-
tigators need to appreciate that indices have properties that can
preclude standard statistical comparison of results among sam-
pling locations (9). If an ecological risk assessment makes use of
indices, the discussion of uncertainty needs to address the limita-
tions of the indices and acknowledge the assumptions that they
make.
Field Methods
The following list includes a brief description, by type of
organism, of field methods useful in ecological risk assessments at
Superfund sites. Some methods focus on ways to collect organ-
isms, while others concern ways to examine them.
These methods represent only a selection of those available.
In designing a field study, the investigator should consult the
BTAG, which may suggest approaches not described here. Please
note also that this catalogue includes only methods used in study-
ing biota. For methodology relating to the study of physical and
chemical characteristics of a site, investigators should consult the
following EPA documents:
° Sampler' 5 Guide to the Contract Laboratory Program. EPA/
540/P-90/006, December 1990.
• Compendium ofERT Surface Water and Sediment Sampling
Procedures. EPA/540/P-91/005, January 1991.
• Compendium ofERT Soil Sampling and Surface Geophysics
Procedures. EPA/540/P-91/006, January 1991.
• Compendium of ERT Groundwater Sampling Procedures.
EPA/540/P-91/007, January 1991.
• Compendium ofERT Waste Sampling Procedures. EPA/540/
P-91/008, January 1991.
Periphyton
Scraping, coring, or suction. Field studies of periphyton can
involve collecting these organisms from their natural environment
by means of devices that scrape, core, or use suction (18,30).
Artificial substrate. Materials such as granite, tile, plastic,
and glass can serve as an artificial substrate on which periphyton
communities can develop (18,30).
Data Analysis. Investigators can study the taxonomic compo-
sition, biomass, species richness, and relative abundance of per-
iphyton communities from either natural habitats or artificial
substrates. In addition, analysis of data can yield information about
diversity, evenness, and similarity (18, 30).
Plankton
Trapping, pumping, netting, and using closing samplers
Samples can be collected from natural substrates by means ol
traps, pumps, nets, and closing samplers such as tubes and bottle;
(3,18,30).
Data analysis. After identifying the organisms in the sample
investigators can determine species richness, relative abundance
and diversity (18).
Benthic Macroinvertebrates
Dredging and digging. Dredgi ig and digging provide quali
tative samples from the natural environment (17,18).
Stream netting, coring, or sampling with a grab. Strean
netting, coring and sampling with a grab collect quantilativi
samples from the natural environment Stream netting involve:
using specialized nets to collect samples. The Surber and the Hes:
are stream nets commonly used to sample macroinvertebrates in o
on substrate. Some types of stream nets collect macroinvertebrate:
drifting in the water column (a normal occurrence with benthii
macroinvertebrates inhabiting flowing water). A grab is a sam
pling device with jaws that penetrate and extract an area of thi
substrate (1,4.12,17,18,21).
Sweep netting. Sweep nets collect qualitative samples associ
ated with aquatic vegetation (17.18).
Sampling with other devices. More quantitative methods o
sampling benthic macroinvertebrates associated with aquatic veg
elation involve using either the Wilding stovepipe or the Macan
the Minto, or the McCauley samplers (17,18,2.';.
Artificial substrate. Communities of benthic macro
invertebrates can develop on artificial substrates introduced inu
the site's surface water (17,18,21).
Data analysis. Once the sample has been collected, th
investigator can identify the species present and measure biomass
Further analysis of data can disclose such parameters as specie
richness, species density, diversity, and relative abundance (7/
18,21).
Fish
Seining. Seines are effective sampling devices for shallov
waters such as streams, nearshore areas of lakes, and shallo\
marine and estuarine locations. The most commonly used sein
consists of a specialized net attached to long vertical poles (4,21
30).
Trawling. In deeper waters that have no obstructions, inves
tigators use a tapered conical fishing net called a trawl. A boat pull
the trawl through the water at a specified depth (18,21,30).
Passive netting. For passive netting, the field biologist ai
taches a net to the bottom of a river or lake. Fish that swim into th
net become entangled or unable to escape. Passive nets include gil
trammel, and hoop nets (20,18,21,30).
Electrofishing. This technique, which applies an electric;
charge to a small area in a body of water, momentarily immobilize
ECO Update
March 1994-Vol. 2, No.
-------
i.wi. Electrofishing is effective for sampling fish in streams, rivers,
and lakes (18,21.30).
Chemical collection. This specialized technique involves
exposing the animals to fish toxicants (27). Investigators should
familiarize themselves with state regulations regarding the use of
these substances. While use of such chemicals is a standard
procedure, this method is not preferred because of its negative
effects.
Fish tissue collection. Methods for collecting fish tissue are
described in References 25,27, and 28.
Data analysis. Once the investigator has identified the fish, he
or she can determine such measurement endpoints as relative
abundance and species richness (18.21,30).
Terrestrial Vegetation
The methods described for terrestrial vegetation work equally
well for upland and wetland areas. Th ; is true even though in
wetlands, by definition, the prevailing vegetation is typically
adapted to saturated soil conditions.
Remote sensing. Remote sensing, which uses either satellite
imagery or aerial photography, is useful when contamination of a
site has resulted in restricted access or when initial site reconnais-
sance requires surveys of large areas. The technique provides
information about general landscape patterns, gross features of the
vegetation, and photosynthetic rates. Infrared and multispectral
remote sensing also can be used to identify and map areas of
stressed vegetation (13). Usually, some limited ground-level sur-
vey (ground-truthing) is required to verify identification of species
and condition.
Quadrats and transects. Quadrats and transects are often used
in vegetation survey and sampling methods to provide a more
quantitative approach to collecting data. Quadrats are closed sam-
pling units or plots. Transects consist of belts, strips, or lines used
as a sampling unit Both methods define precise, isolated areas for
sampling, recording, mapping, or studying organisms within a
larger area. Both methods allow investigators to estimate character-
istics such as cover, species frequency, and density (2,70).
Point method. The point method estimates cover using sam-
pling points (2, 70).
Distance methods. Distance methods provide a means of
estimating coverage and species density in forests, which would
require large quadrats to sample trees adequately. There are
several different versions of distance methods but in general the
methods are based on measuring distances between random points
and the sampled plants, or between individual plants (2, 70).
Soil Fauna
Coring. Field biologists collect samples by coring devices
(23).
Driving organisms from soil sample. Heat, moisture, or
chemical stimuli drive the organisms from the soil into collection
chambers (23).
Sieving. Sieving can be used to retrieve the fauna from the
soil. Dry sieving separates soil fauna from fallen leaves and friable
soil. Wet sieving, also called soil washing, is used to extract
organisms from fine mud, sediments, and leaf litter (23).
Density separation. Flotation, centrifugation, and sedimenta-
tion separate organisms from soil on the basis of density (23).
Data analysis. After the investigator has identified the organ-
isms, he or she can determine parameters that characterize the
community.
Terrestrial and Flying Insects
Trapping. Traps can be used to collect insects of particular
species, groups of species, insects at specific life stages, or insects
with specific behaviors. Trapping methods include the use of
attractant chemicals, light, hosts, host substitutes, and insect sounds.
Traps include emergence, pitfall, and sticky traps, to name a few
(23). The type of trap used affects both the range of species
collected and the types of data collected. When collecting several
kinds of insects, the investigator can determine such measurement
endpoints as species diversity (23).
Sign. Frass (feces), nests, cast-off larval cases or cocoons, and
auditory signals indicate the presence of particular insects (23).
Amphibians, Reptiles, and MamnuLs
Auditory and visual study. Visual studies can determine the
presence of species on a site. In addition, sounds can indicate the
presence of certain amphibians and mammals. (79,22).
Sign. Tracks, nests, burrows, dens, scat, or carcasses indicate
which species occur on a site (79,22). '
Trapping. Traps and nets can provide more quantitative means
of sampling and, depending on the breadth of the study, allow an
investigator to determine population and/or community parameters
relative to the reference site. Trapping methods include both live
traps and kill traps. Depending on the study objectives, the investi-
gator either makes observations on live-trapped animals and r
leases them or retains the animals for further study (5,6, 7. 79).
Tissue collection. Methods for collecting tissues are d
scribed in Reference 26.
Birds
Auditory and visual studies. Ornithologists identify the species
at a site by walking specified areas or distances (e.g., along a
transect) and record birds sighted or identified through their songs (5).
Nest success. The evaluation of nest success on the basis of
measures such as clutch size and number of fledglings is practical
only for very large Superfund sites (7).
Trapping. Not practical for most Superfund sites, a variety of
traps and nets can be used to capture birds (6).
Field Studies: Their Contribution
As the previous sections of this Bulletin indicate, field studies
can contribute to all phases of the ecological risk assessment of a
Superfund site and in a variety of ways. Specifically, a well
designed field study can allow investigators to:
• Identify and describe the habitats and species (including
those of special concern) actually or potentially exposed to
waste site contaminants.
• Indicate detrimental ecological effects that may have
curred on or near the site.
• Provide information adding to the weight of evidence linking
adverse effects to the site's contaminants.
• Provide samples for biomarker studies, such as
March 1994-Vol. 2. No. 3
10
ECO Update
-------
bioaccumulation studies, biochemical analyses, and
histopathological studies.13
• Aid in identifying remedial alternatives that are protective of
natural resources.
• Assist in monitoring remediation effectiveness.
Investigators should consult with their Region's BTAG to
determine whether and when to conduct field studies and to select
the studies most appropriate to their sites.
References
1. American Society for Testing and Materials (ASTM). 1988.
Annual Book of ASTM Standards: Water and Environmental
Technology, Vol. 11.04. American Society for Testing and
Materials, Philadelphia, PA.
2. Barbour, M.G., J.H. Burk and W.D. Pitts. 1980. Terrestrial
Plant Ecology. The Benjamin/Cummings Publishing Com-
pany, Inc., Reading, MA.
3. Bloesch, J. (Editor). 1988. Mesocosm Studies. Hydrobiologia
759:221-313. W. Junk, Publishers, Dordrecht, The Nether-
lands.
4. Coull, B. C. 1980. Shallow Water Marine Biological Re-
search. Pages 275-284 in F.P. Diemer, F.J. Vernberg and DZ.
Mirkes (Editors). Ocean Measurements for Marine Biology.
University of South Carolina Press, Columbia, SC.
5. Davis, D.E. and R.L. Winstead. 1980. Estimating the Num-
bersofWildlifePopulations.Pages221-245 in S.D. Schemnitz
(Editor). Wildlife Management Techniques Manual. Fourth
Edition. The Wildlife Society, Washington, DC.
6. Day, G.I., S.D. Schemnitz and R.D. Taber. 1980. Capturing
and Marking Wild Animals. Pages 61-88 in S.D. Schemnitz
(Editor). Wildlife Management Techniques Manual. Fourth
Edition. The Wildlife Society, Washington, DC.
7. Downing, R.L. 1980. Vital Statistics of Animal Populations.
Pages 247-267 in S.D. Schemnitz (Editor). Wildlife Manage-
ment Techniques Manual. Fourth Edition. The Wildlife'Soci-
-ty, Washington, DC.
8. Escherich, P. and D. Rosenberger. 1987. Guidance on Use of
Habitat Evaluation Procedures and Habitat Suitability Index
Models for CERCLA Applications. U.S. Department of the
Interior, CERCLA 301 Project, Washington, DC.
9. Greig-Smith, P. 1983. Quantitative Plant Ecology. Third
Edition. University of California Press, Berkeley,. CA.
10. Green, R.H. 1979. Sampling Design and Statistical Methods
for Environmental Biologists. J. Wiley and Sons, New York,
NY.
11. Hair, J.D. 1980. Measurement of Ecological Diversity. Pages
269-275 in S.D. Schemnitz (Editor). Wildlife Management
Techniques Manual. Fourth Edition. The Wildlife Society,
Washington, DC.
13 A biomarker is a physiological, biochemical, or histological
response that is measured in individual organisms and that indicates either
exposure or sub-lethal stress.
12. Hess, A.D. 1941. New Limnological Sampling Equipmeni
Limnol. Soc. Amer. Spec. Publ. 6:1-5.
13. Kapustka, L.A. 1989. Vegetation Assessment. Section 8.3 ii
Warren-Hicks, W., B.R. Parkhurst, and S.S. Baker Jr. (Edi
tors). Ecological Assessment of Hazardous Waste Sues: i
FieldandLaboratoryReference.EPA/6M/3-%9/Q13.Envuor
mental Research Laboratory, Office of Research and Develop
ment, U.S. Environmental Protection Agency, Corvallis, OF
14. Karr, J.R. 1981. Assessment of Biotic Integrity Using Fis
Communities. Fisheries 6:21-27'.
15. Karr,J.R., K.D.Fausch,P.L. Angermeier,P.R. Yant,andL
Schlosser. 1986. Assessing Biological Integrity in Runnin
Waters: A Method and Its Rationale. Illinois Natural Histor
Survey, Special publ. No. 5.
16. Kirkpatrick, R.L. 1980. Physiological Indices in Wildlil
Management. Pages 99-112 in S.D. Schemnitz (Editor
Wildlife Management Techniques Manual. Fourth Editioi
The Wildlife Society, Washington, DC.
17. Klemm,DJ.,P.A.Lewis,F.Fulk,andJ.M.Lazorchak. 199(
Macroinvertebrate Field and Laboratory Methods for Evah
ating the Biological Integrity of Surf ace Waters. EPA/600A
90/030. Environmental Monitoring Systems Laboratory-
Cincinnati, Office of Modeling, Monitoring Systems, an
Quality Assurance, U.S. Environmental Protection Agenc;
Cincinnati, OH.
18. LaPoint, T.W. and J.F. Fairchild. 1989. Aquatic Survey
Section 8.2 in Warren-Hicks, W., B.R. Parkhurst, and S.!
Baker Jr. (Editors). Ecological Assessment of Hazardoi
Waste Sites: A Field and Laboratory Reference. EPA/600/;
89/013. Environmental Research Laboratory, Office of R(
search and Development, U.S. Environmental Protectic
Agency, Corvallis, OR.
19. McBee, K. 1989. Field Surveys: Terrestrial Vertebrate
Section 8.4 in Warren-Hicks, W., B.R. Parkhurst, and S.!
Baker Jr. (Editors). Ecological Assessment of Hazardoi
Waste Sites: A Field and Laboratory Reference. EPA/600A
89/013. Environmental Research Laboratory, Office of Ri
search and Development, U.S. Environmental Protectic
Agency, Corvallis, OR.
20. Nielsen, L.A. and DJL. Johnson (Editors). 1983. Fishii
Techniques. American Fisheries Society, Bethesda, MD.
21. Plafkin, J.L., M.T. Barbour, K.D. Porter, S.K. Gross, ai
R.M. Hughes. 1989. RapidBioassessment Protocolsfor U,
in Streams and Rivers :BenthicMacroinvertebrates and Fis
EPA/600/4-89-001. Assessment and Watershed Protectic
Division, Office of Water, U.S. Environmental Protectu
Agency, Washington, D.C.
22. Smith, R.L. 1966. Ecology and Field Biology. Harper ai
Row, New York, NY.
23. Southwood,T.R.E. l91&.EcologicalMethods:WithPartic
lor Reference to the Study of Insect Populations. Secoi
Edition. John Wiley and Sons, New York, NY.
24. Suter, G. 1989. Ecological Endpoints. Chapter 2 in Warre
Hicks, W., B.R. Parkhurst, and S.S. Baker Jr. (Editor:
Ecological Assessment of Hazardous Waste Sites: A Fie
ECO Update
U
March 1994-Vol. 2, No.
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and Laboratory Reference. EPA/600/3-89/013. Environ-
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ment, U.S. Environmental Protection Agency, Corvallis, OR.
25. U.S. Environmental Protection Agency. 1981. Interim Meth-
ods for the Sampling and Analysis of Priority Pollutants in
Sediments and Fish Tissue. EPA/600/4-81/055. Environ-
mental Monitoring Systems Laboratory, Cincinnati, OH.
26. U.S. Environmental Protection Agency. 1982. Test Methods
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S W-A46.2nd edition. Office of Solid Waste and Emergency
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27. U.S. Environmental Protection Agency. 1990. Analytical
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tion ofPCDDIPCDF in Fish. EPA7600/3-90/022. Environ-
mental Research Laboratory, Duluth, MM.
28. U.S. Environnr"ital Protection Agency. '990. Analytical
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tion ofXenobiotic Contaminants in Fish. EPA/600/3-90/023.
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29. U.S. Environmental Protection Agency. 1992. Framework
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30. Weber, C.I. (Editor). 1973. Biological Field and Laboratory
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Additional Print Resources
Available from the Federal
Government
Adamus, P.R. et al. 1991. Wetland Evaluation Technique. Vol*
1: Literature Review and Evaluational Rationale. Technical
Report WRP-DE-2. U.S. Army Corps of Engineers.
Baker, B. and M. Kravitz. 1992. Sediment Classification Meth-
ods Compendium. EPA/823/R-92/006. U.S. EPA Office of
Water.
Beyer, W.N. 1990. Evaluating Soil Contamination. Biological
Report 90(2). U.S. Department of Interior.
Fletcher.J. and H.Ratsch. l990.PlantTierTesting:A Workshop
to Evaluate Nontarget Plant Testing in Subdivision J Pesti-
cide Guidelines. EPA/600/9-91/041.
Linder, G. et al. 1992. Evaluation ofTerr^tnd Indicators for
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EPA/600/R-92/183. Office of Research and Development,
ERL-Corvallis, OR.
U.S. Environmental Protection Agency. 1988. Guidance for
Conducting Remedial Investigations and Feasibility Studies
under CERCLA. EPA/540/G-89/004.
March 1994'Vol. 2 .No. 3
12
ECO Update
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APPENDIX A
Bibliography
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BIBLIOGRAPHY
COURSE MATERIALS
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Development, Office of Health and Environmental Assessment, and Environmental Criteria and
Assessment Office, Cincinnati, OH.
Verschueren, K. 1983. Handbook of environmental data on organic chemicals. Van Nostrand
Reinhold, New York.
8/93 11 Bibliography
-------
APPENDIX B
Supplementary Materials
-------
EXPOSURE PATHWAYS AT SPRENGER'S LANDFILL
Potentially
Exposed Population
Exposure Route. Medium,
and Exposure Point
Pathway
Selected for
Evaluation?
Reason for Selection
or Exclusion
Current Land Use
Site visitors
(8- to 18-year-old
child)
Site visitors
(8- to 18-year-old
child)
Residents (adult)
Residents (adult)
Residents (adult)
Residents/visitors
(8- to 18-year-old
child)
Residents/visitors
(8- to 18-year-old
child)
Residents/visitors
(8- to 18-year-old
child)
Golfers (adult)
Ingestion of chemicals of Yes
potential concern in soils
onsite
Direct contact with Yes
chemicals of potential
concern in soils onsite
Ingestion of groundwater Yes
from local wells
downgradient of site
Inhalation of chemicals Yes
volatilized from
groundwater during home
use
Direct contact with Yes
chemicals of potential
concern in groundwater
Direct contact with Yes
chemicals of potential
concern in offsite soils
and in sediments in
streams offsite
Ingestion of chemicals of Yes
potential concern in
offsite soils and in
sediments offsite
Direct contact with Yes
chemicals of concern in
water in streams offsite
Direct contact with Yes
chemicals of potential
concern in water in
streams offsite
Contaminated soil is
in an area potentially
used by site visitors
Contaminated soil is
in an area potentially
used by site visitors
Residents use
groundwater from
local wells as drinking
water
Some of the
chemicals of potential
concern in
groundwater are
volatile, and ground
water is used by local
residents
Residents use
groundwater from
local wells for bathing
Some of the
chemicals of potential
concern are found in
sediments offsite
Some of the
chemicals of potential
concern are found in
sediments offsite
Contaminated streams
are in an area
potentially used by
children
Contaminated streams
are in an area
potentially used by
golfers
8/93
Exposure Assessment
-------
EXPOSURE PATHWAYS (cont.)
Potentially
Exposed Population
Exposure Route, Medium,
and Exposure Point
Pathway
Selected for
Evaluation?
Reason for Selection
or Exclusion
Golfers (adult)
Residents (adult)
Future Land Use
Residents (adult)
Residents (adult)
Residents (adult)
Residents (adult)
Residents (child and
adult)
Residents (child)
Residents (adult)
Direct contact with
chemicals of potential
concern in sediments in
streams offsite
Inhalation of chemicals
volatilized from site and
transported downwind
Inhalation of chemicals in
soil blown downwind of
site
Ingestion of groundwater
from local wells
downgradient of site
Inhalation of chemicals
volatilized from
groundwater during home
use
Direct contact with
chemicals of potential
concern in groundwater
Ingestion of chemicals of
potential concern in soils
onsite
Direct contact with
chemicals of potential
concern in soils onsite
Inhalation of chemicals
volatilized from site and
transported downwind
Yes Some of the
chemicals of potential
concern are found in
sediments offsite
No Because of the age of
the site, volatile
chemicals would be
dissipated by this
time
Yes Some chemicals of
concern are not
volatile and could be
transported with soil
particles
Yes Area could be
developed as a
residential area
Yes Some of the
chemicals of potential
concern in
groundwater are
volatile, and the area
could be developed in
the future as a
residential area
Yes Area could be
developed as a
residential area
Yes Contaminated soil is
in an area that could
be developed as a
residential area
Yes Contaminated soil is
in an area that could
be developed as a
residential area
No Because of the age of
the site, volatile
chemicals would be
dissipated by this
time
Exposure Assessment
8/93
-------
EXPOSURE PATHWAYS (cont.)
Pathway
Potentially Exposure Route, Medium, Selected for Reason for Selection
Exposed Population and Exposure Point Evaluation? or Exclusion
Residents (adult) Inhalation of chemicals in Yes Contaminated soil is
site soil blown downwind in an area that could
of site be developed as a
residential area
8/93 3 Exposure Assessment
-------
QUANTIFYING EXPOSURE: INTAKE NUMBERS
Groundwater: Ingestion
The following equation and assumptions were used to calculate intakes for ingestion of chemicals in
groundwater from wells used by residents. The equation is found in the Human Health Evaluation
Manual: Part A.
GDI (mglkg-day) =
CWxIRx EFx ED
BWxAT
where:
CW = contaminant concentration in water (mg/L)
IR = 2 liters/day (U.S. EPA 1989)
EF = 350 days/year (U.S. EPA 1991)
ED = 30 years (U.S. EPA 1991)
BW = 70 kg (U.S. EPA 1991)
AT = 30 years = 10,950 days (noncarcinogenic)
70 years = 25,550 days (carcinogenic).
Land Use: Current Future (circle one)
Receptor: Nearest resident (Caretaker)
Pathway: Ingestion of chemicals in groundwater from local wells
downgradient of site
Chemical
Benzene
Chlorobenzene
1,2-Dichloroethene
Trichloroethylene
Vinyl chloride
Barium
Manganese
Zinc
Concentration
(j/g/U
30
58
700
180
130
29
5,150
79
CDI Noncancer
(mg/kg-day)
8.2E-4
1 .6E-3
1.9E-2
4.9E-3
3.6E-3
7.9E-4
1.4E-1
2.2E-3
CDI Cancer
(mg/kg-day)
3.5E-4
6.8E-4
8.2E-3
2.1E-3
1.5E-3
3.4E-4
6.1E-2
9.3E-4
8/93
Quantifying Exposure: Intake Numbers
-------
Land Use: Current Future (circle one)
Receptor: Resident
Pathway: Ingestion of chemicals in groundwater from onsite wells
Chemical
Benzene
Chlorobenzene
1,2-Dichloroethene
Napthalene
Phenol
Toluene
Trichloroethene
Vinyl chloride
Aroclor 1 254
Barium
Chromium
Manganese
Zinc
Concentration
U/g/L)
1,200
300
39,000
202
22
1 2,000
1 80,000
6,900
933
1,910
13
20,500
174
CDI Noncancer
(mg/kg-day)
3.3E-2
8.2E-3
1.1
5.5E-3
6.0E-4
3.3E-1
4.9
1.9E-1
2.6E-2
5.2E-2
3.6E-4
5.6E-1
4.8E-3
CDI Cancer
(mg/kg-day)
1 .4E-2
3.5E-3
4.6E-1
2.4E-3
2.6E-4
1.4E-1
2.1
8.1E-2
1.1 E-2
2.2E-2
1.5E-4
2.4E-1
2.0E-3
Groundwater: Inhalation
The following equation was used to calculate intakes for inhalation of chemicals volatilized from
groundwater during home use. The equation was taken from the Human Health Evaluation Manual,
Part B: Development of Risk-based Preliminary Remediation Goals (page 52, B.I. 2), with a slight
modification to fit the format of Part A. It addresses volatilization of contaminants from all the
residential water used in a house, not just during showering.
CDI Wkg-day) - CWxKxIRxEFxED
BWxAT
where:
CW = contaminant concentration in water (mg/L)
K = volatilization factor (0.0005 x 1,000 L/m3; Andelman
1990)
IR = 15 mj/day (U.S. EPA 1991)
EF = 350 days/year (U.S. EPA 1991)
Quantifying Exposure: Intake Numbers 2 8/93
-------
ED
BW
AT
30 years (U.S. EPA 1991)
70 kg (U.S. EPA 1991)
30 years = 10,950 days (noncarcinogenic)
70 years = 25550 days (carcinogenic).
Land Use: Current Ftrtwe (circle one)
Receptor: Nearest resident (Caretaker)
Pathway: Inhalation of chemicals volatilized from groundwater during
home use
Concentration
Chemical (jvg/L)
Benzene
Chlorobenzene
1,2-Dichloroethene
Trichloroethene
Vinyl chloride
30
58
700
180
130
CDI Noncancer
(mg/kg-day)
3.1E-3
6.0E-3
7.2E-2
1.9E-2
1 .3E-2
CDI Cancer
(mg/kg-day)
1 .3E-3
2.6E-3
3.1E-2
7.9E-3
5.7E-3
Land Use: Current Future
Receptor: Resident (onsite)
(circle one)
Pathway: Inhalation of chemicals volatilized from groundwater during
home use
Chemical
Benzene
Chlorobenzene
*
1,2-Dichloroethene
Napthalene
Phenol
Toluene
Trichloroethene
Vinyl chloride
Concentration
(pg/L)
1,200
300
39,000
202
22
12,000
180,000
6,900
CDI Noncancer
(mg/kg-day)
1.2E-1
3.1E-2
4.0
2.1E-2
2.3E-3
1.2
18.5
7.1E-1
CDI Cancer
(mg/kg-day)
5.3E-2
1.3E-2
1.7
8.9E-3
9.7E-4
5.3E-1
7.9
3.0E-1
8/93
Quantifying Exposure: Intake Numbers
-------
Groundwater: Dermal
The following equations were used to calculate absorbed doses for dermal contact with chemicals in
groundwater used in Jthe home. The equations are taken from Dermal Exposure Assessment:
Principles and Applications (U.S. EPA 1992).
DAmM xEVxED xEF xA
DAD = ——
BWxAT
where:
DAD = dermally absorbed dose (mg/kg-day)
DA^t = absorbed dose per event (mg/cm2-event)
EV = 1 event/day (U.S. EPA 1992)
EF = 350 days/year (U.S. EPA 1991)
ED = 30 years (U.S. EPA 1991)
A = 20,000 cm2 (average adult surface area; U.S. EPA 1992)
BW = 70 kg (U.S. EPA 1991)
AT = 30 years = 10,950 days (noncarcinogenic)
70 years = 25,550 days (carcinogenic).
For inorganics, DAeven< (mg/cm2-event) was calculated as follows:
~ *? *
where:
= dose absorbed per unit area per event (mg/cm2-event)
Kp = permeability coefficient from water (cm/hour)
CW = contaminant concentration in water (mg/cm3)
tevent = 15 minutes = 0.25 hours/event (U.S. EPA 1992)
Values for K* were taken from Table 5-8 of Dermal Exposure Assessment: Principles and
Applications (U.S. EPA 1992).
For organics, DAevent (mg/cm2-event) was calculated as follows:
If t ^ t * thfn' DA = t V C1
V 'event < * ' mSn- UAevent L *p C
Quantifying Exposure: Intake Numbers 4 8/93
-------
'event
1 + B
+ 2 T
Values for t*, T, and B were taken from Table 5-8 of Dermal Exposure Assessment: Principles and
Applications (U.S. EPA 1992).
Land Use: Current Future (circle one)
Receptor: Nearest resident (Caretaker)
Pathway: Dermal contact with chemicals in groundwater used for
• bathing
Chemical
Concentration
(//g/L)
Benzene 30
Chlorobenzene 58
1,2-Dichloroethene 700
Trichloroethene 180
Vinyl chloride 130
Barium 29
Manganese 5,150
Zinc 79
DAD Noncancer
(mg/kg-day)
1.2E-4
6.0E-4
1.6E-3
8.3E-4
1.6E-4
2.0E-6
3.6E-4
3.2E-6
DAD Cancer
(mg/kg-day)
5.1E-5
2.6E-4
6.6E-4
3.6E-4
7.0E-5
8.5E-7
1.5E-4
1.4E-6
8/93
Quantifying Exposure: Intake Numbers
-------
Land Use: Current Future (circle one)
Receptor: Resident (onsite)
Pathway: Dermal contact with chemicals in groundwater used for
, bathing
Chemical
Benzene
Chlorobenzene
1,2-Dichloroethene
Napthalene
Phenol
Toluene
Trichloroethene
Vinyl chloride
Aroclor 1 254
Barium
Chromium
Manganese
Zinc
Concentration
(//g/L)
1,200
300
39,000
202
22
12,000
1 80,000
6,900
933
1,910
13
20,500
174
DAD Noncancer
(mg/kg-day)
4.9E-3
3.0E-3
8.6E-2
3.8E-3
2.6E-5
1.1 E-2
8.1E-1
8.7E-2
1.0
1 .3E-4
8.3E-6
1 .4E-3
7.2E-6
DAD Cancer
, (mg/kg-day)
2.1E-3
3.1E-3
3.7E-2
1 .6E-3
1.1 E-5
5.0E-2
3.6E-1
3.7E-2
4.5E-1
5.7E-5
3.6E-7
6.0E-4
3.0E-6
Soil/Sediment: Ingestion
The following equation was used to calculate intake rates for ingestion of chemicals of onsite and
offsite soils by site visitors. The same equation was used to calculate intake rates for ingestion of
chemicals in offsite sediments by site visitors. The equation was taken from the Human Health
Evaluation Manual: Part A.
/-nr CS x IR x CF x FI x EF x ED
cm
where:
CS = contaminant concentration in soil (mg/kg)
IR = 100 mg/day - 8-18 year olds (U.S. EPA 1989)
CF = 10-6 kg/mg
FI = 1 (100%)
EF = 12 days/year - site visitors (8-18 year olds)
Quantifying Exposure: Intake Numbers 6
-------
ED = 10 years
BW = 49 kg (U.S. EPA 1989)
AT = 10 years = 3,650 days (noncarcinogenic)
70 years = 25550 days (carcinogenic).
Land Use: Current Rrtwe
Receptor: Site visitor
Pathway: Ingestion of chemicals
Concentration
Chemical (mg/kg)
Benzene 0.650
Benzo(a)pyrene 12.0
Dibenzofuran 1.50
Napthalene 78.0
Toluene 38.0
Trichloroethene 28.0
Aroclor 1 254 27,000
Barium 2.23
Chromium 0.127
Manganese 1 .02
Zinc 25.3
(circle one)
in onsite soils
CDI Noncancer
(mg/kg-day)
4.4E-8
8.1E-7
1 .OE-7
5.2E-6
2.6E-6
1.9E-6
1.8E-3
1.5E-7
8.5E-8
6.9E-8
1.7E-6
CDI Cancer
(mg/kg-day)
6.2E-9
1.1 E-7
1.5E-8
7.4E-7
3.7E-7
2.7E-7
2.6E-4 '
2.1E-8
1.2E-8
1 .OE-8
2.4E-7
Land Use: Current Ftrtwe
Receptor: Site visitor
Pathway: Ingestion of chemicals
Chemical Concentration
(mg/kg)
Dibenzofuran 0.230
Toluene 2.60
Aroclor 1 254 1 .40
Barium 0.945
Chromium 0.489
Manganese 0.739
Zinc 0.088
(circle one)
in offsite soils
CDI Noncancer
(mg/kg-day)
1.6E-8
1.7E-7
9.2E-8
6.3E-8
3.3E-8
5.0E-8
5.9E-9
CDI Cancer
(mg/kg-day)
2.2E-9
2.5E-8
1.4E-8
9.1E-9
4.7E-9
7.1E-9
8.4E-10
8/93
Quantifying Exposure: Intake Numbers
-------
Land Use: Current Future (circle one)
Receptor: Site visitor
Pathway: Ingestion of chemicals in offsite sediments
Chemical
Benzene
Benzo(a)pyrene
1 ,2-Dichloroethene
Fluoranthene
Napthalene
Pyrene
Toluene
Vinyl chloride
Aroclor 1 254
Barium
Chromium
Lead
Manganese
Zinc
Concentration
(mg/kg)
0.340
0.960
0.170
2.00
0.270
1.90
0.140
0.094
90.0
1.580
0.423
0.418
1.870
0.927
CDI Noncancer
(mg/kg-day)
2.3E-8
6.4E-8
1.1 E-8
1 .4E-7
1.8E-8
1.3E-7
9.2E-9
6.3E-9
6.1E-6
1.1 E-7
2.8E-8
2.8E-8
1.3E-7
6.2E-8
CDI Cancer
(mg/kg-day)
3.2E-9
9.1E-9
1.6E-9
1.9E-8
2.6E-9
1.8E-8
1.4E-9
9.0E-10
8.6E-7
1.5E-8
4.0E-9
3.9E-9
1.7E-8
8.8E-9
The following equation was used to calculate intakes for incidental soil ingestion by residents living
on the site. The equation has two parts to address the different intake rates and body weights of an
adult and a child. This equation is an expansion of the equation found on page 6-40 of the HHEM:
Part A.
Intake (mg/kg/day) =
CS x IRc x CF x FIc x EFc x EDc
BWc x AT
CS x IRa x CF x Fla x EFa x EDa
BWa x AT
Quantifying Exposure: Intake Numbers g 8/93
-------
where:
cs
IRc
IRa
CF
FIc,a
EFc,a
EDc
EDa
BWc
BWa
AT
= contaminant concentration in soil (mg/kg)
= 200 mg/day - child (1-6 years old) (U.S. EPA 1991)
= 100 mg/day - adult (7-30 years old) (U.S. EPA 1991)
= 10-6 kg/mg
= 1 (100%)
= 350 days/year (U.S. EPA 1991)
= 6 years - child (U.S. EPA 1991)
= 24 years - adult (U.S. EPA 1991)
= 15 kg - child (U.S. EPA 1991)
= 70 kg - adult (U.S. EPA 1991)
= 30 years = 10,950 days (noncarcinogenic)
70 years = 25,550 days (carcinogenic).
Land Use: Current Future (circle one)
Receptor: Resident (onsite)
Pathway: Ingestion of chemicals in onsite soils
Concentration CDI Noncancer
Chemical (mg/kg) (mg/kg-day)
Benzene 0.650 2.4E-6
Benzo(a)pyrene 12.0 4.4E-5
Dibenzofuran 1.50 5.6E-6
Napthalene 78.0 2.9E-4
Toluene 38.0 1 .4E-4
Trichloroethene 28.0 1 .OE-4
Aroclor1254 27,000 9.9E-2
Barium 2.23 8.3E-6
Chromium 0.127 4.7E-7
Manganese 1.02 3.8E-6
Zinc 25.3 9.3E-5
CDI Cancer
(mg/kg-day)
1 .OE-6
1.9E-5
2.4E-6
1 .2E-4
6.0E-5
4.4E-5
4.3E-2
3.6E-6
2.0E-7
1.6E-6
4.0E-5
Soil/Sediment: Dermal
The following equation was used to calculate absorbed doses for dermal contact with chemicals in
onsite and offsite soils and offsite sediments. The equation was taken from Dermal Exposure
Assessment: Principles and Applications (U.S. EPA. 1992).
8/93 9 Quantifying Exposure: Intake Numbers
-------
DAD (mglkg-day) - CS x AF X ABS x EF X ED X A
where:
DAD = dermally absorbed dose (mg/kg-day)
CS = contaminant concentration in soil (mg/kgXlO"6 kg/mg)
AF = 1.0mg/cm2-event(U.S. EPA 1992)
ABS = 6% for Aroclor (PCB) (U.S. EPA 1992)
EF = 12 events/year for site visitors
40 events/year for site residents (based on 2 days/week, 5 months/year; Hawley
1985)
ED = 10 years - site visitors (noncarcinogenic)
30 years - resident (noncarcinogenic)
A = 3,600cm2-site visitors (25% of 14,400cm2)
5,000 cm2 - site residents (25% of 20,000 cm2)
25% of total body surface area was used to represent summer attire (U.S. EPA
1992)
BW = 49 kg - site visitors
70 kg - site residents
AT = 10 years = 3,650 days - site visitor (noncarcinogenic)
30 years = 10,950 days - site resident (noncarcinogenic)
70 years = 25,550 days (carcinogenic).
Land Use: Current Future (circle one)
Receptor: Site visitor
Pathway:' Dermal contact with chemicals in onsite soils
Chemical
Aroclor 1254
Concentration
(mg/kg)
27,000
DAD Noncancer
(mg/kg-day)
3.9E-3
DAD Cancer
(mg/kg-day)
5.6E-4
Land Use: Current Future (circle one)
Receptor: Site visitor
Pathway: Dermal contact with chemicals in offsite soils
Concentration DAD Noncancer DAD Cancer
Chemical (mg/kg) (mg/kg-day) (mg/kg-day)
Aroclor 1254 1.40 2.0E-7 2.9E-8
Quantifying Exposure: Intake Numbers 10 8/93
-------
Land Use: Current Future (circle one)
Receptor: Site visitor
Pathway: Dermal contact with chemicals in offsite sediments
Concentration DAD Noncancer DAD Cancer
Chemical (mg/kg) (mg/kg-day) (mg/kg-day)
Aroclor 1254 90.0 1.3E-5 1.9E-6
Land Use: Current Future (circle one)
Receptor: Resident (onsite)
Pathway: Dermal contact with chemicals in onsite soils
Chemical Concentration DAD Noncancer DAD Cancer
(mg/kg) (mg/kg-day) (mg/kg-day)
Aroclor 1254 27,000 1.2E-2 5.0E-3
Surface Water: Dermal
i
i
The following equations were used to calculate absorbed doses for dermal contact with chemicals in
offsite surface water. The equations are taken from Dermal Exposure Assessment: Principles and
Applications (U.S. EPA 1992).
x EVxEDxEFxA
DAD = ——
BWxAT
where:
DAD = dermally absorbed dose (mg/kg-day)
DA^eni = absorbed dose per event (mg/cm2-event)
EV = 1 event/day (U.S. EPA 1992)
EF = 12 days/year - site visitors (U.S. EPA 1991)
130 days/year - golfers (worst case assumption)
ED = 10 years - site visitors (U.S. EPA 1991)
20 years - golfers
A = 2,880 cm2 - hands, feet and legs = 20% of total body surface - site visitors
840 cm2 - hands - golfers (U.S. EPA 1989)
BW = 49 kg - site visitor (average weight for 9-18 year olds)(U.S. EPA 1989)
70 kg - golfer
AT = 10 years = 3,650 days - site visitor (noncarcinogenic)
20 years = 7,300 days - golfer (noncarcinogenic)
70 years = 25,550 days (carcinogenic).
8/93 11 Quantifying Exposure: Intake Numbers
-------
For inorganics,
(mg/cm2-event) was calculated as follows:
CW x
K*
CW
where:
dose absorbed per unit area per event (mg/cm2-event)
permeability coefficient from water (cm/hr)
contaminant concentration in water (mg/cm3)
2 hours/event - site visitor
8.3 x la3 hour (O.5 minutes) - golfer.
Values for K£ were taken from Table 5-8 of the Dermal Exposure Assessment: Principles and
Applications (U.S. EPA 1992).
For organics,
cm2-event) was calculated as follows:
= 2 K
Values for t*, T, and B were taken from Table 5-8 of the Dermal Exposure Assessment: Principles
and Applications (U.S. EPA 1992).
Quantifying Exposure: Intake Numbers
12
8/93
-------
Land Use: Current
Receptor: Site visitor
Rrtufe (circle
one)
Pathway: Dermal contact with chemicals in offsite surface
Chemical
Benzene
1,2-Dichloroethene
Napthalene
Toluene
Trichloroethene
Vinyl chloride
Aroclor 1 254
Barium
Chromium
Manganese
Zinc
Concentration
0/g/L)
160
14
99
5
10
15
1.7
810
17
5,360
179
DAD Noncancer
(mg/kg-day)
1 .7E-5
7.2E-7
3.7E-5
1.1 E-6
9.7E-7
5.3E-6
3.9E-5
3.1 E-6
6.6E-.8
2.0E-5
4.1E-7
water
DAD Cancer
(mg/kg-day)
2.4E-6
1.0E-7
5.4E-6
1 .6E-7
1 .4E-7
7.4E-7
5.4E-6
4.4E-7
9.3E-9
8.9E-6
6.0E-8
Land Use: Current
Receptor: Golfer
Rrtwe (circle
one)
Pathway: Dermal contact with chemicals in offsite surface
Chemical
Benzene
1 ,2-Dichloroethene
Napthalene
Toluene
Trichloroethene
Vinyl chloride
Aroclor 1254
Barium
Chromium
Manganese
Zinc
Concentration
(fjgll)
160
14
99
5
10
15
1.7
810
17
5,360
179
DAD Noncancer
(mg/kg-day)
1.8E-6
8.8E-8
5.4E-6
1 .4E-7
1.3E-7
5.4E-8
5.5E-6
2.9E-6
6.0E-10
1.9E-7
6.3E-8
water
DAD Cancer
(mg/kg-day)
5.2E-7
2.5E-8
1 .5E-6
3.9E-8
3.6E-8
1.5E-8
1.6E-6
8.2E-9
1.7E-10
5.4E-8
1.8E-9
8/93
13
Quantifying Exposure: Intake Numbers
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REFERENCES
Andelman, J.B. 1990. Total exposure to volatile organic chemicals in potable water. N.M. Ram,
R.F. Christman, and K.P. Cantor (eds). Lewis Publishers, Inc., Boca Raton, Florida.
Hawley, J.K. 1985. Assessment of health risk from exposure to contaminated soil. Risk Anal.
5:289-302.
U.S. EPA 1989. Exposure factors handbook. EPA/600/8-89/043. U.S. Environmental Protection
Agency, Office of Health and Environmental Assessment, Exposure Assessment Group, Washington,
DC.
U.S. EPA 1991. Risk assessment guidance for Superfund. Volume 1: human health evaluation
manual supplemental guidance: standard default exposure factors. Interim Final Report. OSWER
Directive 9285.6-03. U.S. Environmental Protection Agency, Office of Emergency and Remedial
Response, Toxics Integration Branch, Washington, DC.
U.S. EPA 1992. Dermal exposure assessment: principles and applications. EPA/600/8-91/01 IB.
Interim Report. U.S. Environmental Protection Agency, Office of Research and Development,
Washington, DC.
Quantifying Exposure: Intake Numbers 14 8/93
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