Procedures For The Derivation Of Equilibrium Partitioning Sediment Benmarks(ESBS) For The Protection OF Benthic Organisms Dieldrin

&EPA
United States
Environmental Protection
Agency
Office of Research and Development
Washington, DC 20460
EPA-600-R-02-010
www.epa.gov
Procedures for the Derivation of
Equilibrium Partitioning
Sediment Benchmarks (ESBs)
for the Protection of Benthic
Organisms: Dieldrin
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EPA/600/R-02/010
August 2003

Procedures for the Derivation of

Equilibrium Partitioning Sediment Benchmarks (ESBs)

for the Protection of Benthic Organisms: Dieldrin

Walter J. Berry*
Robert M. Burgess**
National Health and Environmental Effects Research Laboratory
Atlantic Ecology Division
Narragansett, RI

David J. Hansen
HydroQual, Inc., Mahwah, NJ
Great Lakes Environmental Center, Traverse City, MI (formerly withU.S. EPA)

Dominic M. DiToro
Manhattan College, Riverdale, NY; HydroQual, Inc.,
Mahwah, NJ

Laurie D.DeRosa
HydroQual, Inc., Mahwah, NJ

Heidi E. Bell*
Mary C. Reiley
Office of Water, Washington, DC

Frank E. Stancil, Jr.
National Exposure Research Laboratory
Ecosystems Research Division
Athens, GA

Christopher S. Zarba
Office of Research and Development, Washington, DC

David R. Mount
Robert L. Spehar
National Health and Environmental Effects Research Laboratory
Mid-Continent Ecology Division
Duluth, MN
* Principle U.S. EPA Contacts
** Document Editor

U.S. Environmental Protection Agency
Office of Research and Development
National Health and Environmental Effects Research Laboratory
Atlantic Ecology Division, Narragansett, RI
Mid-Continent Ecology Division, Duluth, MN
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Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
Notice

The Office of Research and Development (ORD) has produced this document to provide procedures for the
derivation of equilibrium partitioning sediment benchmarks (ESBs) for the insecticide dieldrin. ESBs may be useful
as a complement to existing sediment assessment tools. This document should be cited as:

U.S. EPA. 2003. Procedures for the Derivation of Equilibrium Partitioning Sediment Benchmarks
(ESBs) forthe Protection of Benthic Organisms: Dieldrin. EPA-600-R-02-010. Office of Research
and Development. Washington, DC 20460

The information in this document has been funded wholly by the U.S. Environmental Protection Agency. It has
been subject to the Agency's peer and administrative review, and it has been approved for publication as an EPA
document.

Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
Abstract

This equilibrium partitioning sediment benchmark (ESB) document describes procedures to derive concentrations
of the insecticide dieldrin in sediment which are protective of the presence of benthic organisms. The equilibrium
partitioning (EqP) approach was chosen because it accounts for the varying biological availability of chemicals in
different sediments and allows for the incorporation of the appropriate biological effects concentration. This
provides for the derivation of benchmarks that are causally linked to the specific chemical, applicable across
sediments, and appropriately protective of benthic organisms.

The ESBs do not consider the antagonistic, additive or synergistic effects of other sediment contaminants in
combination with dieldrin or the potential for bioaccumulation and trophic transfer of dieldrin to aquatic life, wildlife
or humans.
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Foreword
Foreword
Under the Clean Water Act (CWA), the U. S. Environmental Protection Agency (EPA) and the
States develop programs for protecting the chemical, physical, and biological integrity of the
nation's waters. To support the scientific and technical foundations of the programs, EPA's Office
of Research and Development has conducted efforts to develop and publish equilibrium
partitioning sediment benchmarks (ESBs) for some of the 65 toxic pollutants or toxic pollutant
categories. Toxic contaminants in bottom sediments of the nation's lakes, rivers, wetlands, and
coastal waters create the potential for continued environmental degradation even where water
column contaminant levels meet applicable water quality standards. In addition, contaminated
sediments can lead to water quality impacts, even when direct discharges to the receiving water
have ceased.

The ESBs and associated methodology presented in this document provide a means to estimate the
concentrations of a substance that may be present in sediment while still protecting benthic
organisms from the effects of that substance. These benchmarks are applicable to a variety of
freshwater and marine sediments because they are based on the biologically available
concentration of the substance in the sediments. These ESBs are intended to provide protection to
benthic organisms from direct toxicity due to this substance. In some cases, the additive toxicity
for specific classes of toxicants (e.g., metal mixtures or polycyclic aromatic hydrocarbon
mixtures) is addressed. The ESBs do not consider the antagonistic, additive or synergistic
effects of other sediment contaminants in combination with dieldrin or the potential for
bioaccumulation and trophic transfer of dieldrin to aquatic life, wildlife or humans.

ESBs may be useful as a complement to existing sediment assessment tools, to help assess the
extent of sediment contamination, to help identify chemicals causing toxicity, and to serve as
targets for pollutant loading control measures.

This document provides technical information to EPA Regions, States, the regulated community,
and the public. It does not substitute for the CWA or EPA's regulations, nor is it a regulation
itself. Thus, it cannot impose legally binding requirements on EPA, States, or the regulated
community. EPA and State decisionmakers retain the discretion to adopt approaches on a case-by-
case basis that differ from this technical information where appropriate. EPA may change this
technical information in the future. This document has been reviewed by EPA's Office of Research
and Development (Mid-Continent Ecology Division, Duluth, MN; Atlantic Ecology Division,
Narragansett, RI), and approved for publication.

This is contribution AED-02-047 of the Office of Research and Development National Health and
Environmental Effects Research Laboratory's Atlantic Ecology Division.

Front cover image provided by Wayne R. Davis and Virginia Lee.
IV
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Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
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Contents
Contents
Notice iii

Abstract iii

Forward iv

Acknowledgments x

Executive Summary xii

Glossary xiv
Section 1
Introduction 1-1
1.1 General Information 1-1
1.2 General Information: Dieldrin 1-2
1.3 Applications of Sediment Benchmarks 14
1.4 Overview 14

Section 2
Partitioning 2-1
2.1 Description of EqP Methodology 2-1
2.2 Determination of ^ow for Dieldrin 2-2
2.3 Derivation of KQC from Adsorption Studies 2-2
2.3.1 KQC from Particle Suspension Studies 2-2
2.3.2 KQC from Sediment Toxicity Tests 2-3
2.4 Summary of Derivation of KQC for Dieldrin 24

Section 3
Toxicity of Dieldrin in Water Exposures 3-1
3.1 Derivation of Dieldrin WQC 3-1
3.2 Acute Toxicity in Water Exposures 3-1
3.3 Chronic Toxicity in Water Exposures 3-1
3.4 Applicability of the WQC as the Effects Concentration for Derivation of
Dieldrin ESBWQCs 3-6
VI
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Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
Section 4
Actual and Predicted Toxicity of Dieldrin
in Sediment Exposures 4-1
4.1 Toxicity of Dieldrin in Sediments 4-1
4.2 Correlation Between Organism Response and Interstitial Water Concentration 4-3
4.3 Tests of the Equilibrium Partitioning Prediction of Sediment Toxicity 4-6

Section 5
Derivation of Dieldrin ESBWQCs 5-1
5.1 Derivation of ESBWQCs 5-1
5.2 Uncertainty Analysis 5-2
5.3 Comparison of Dieldrin ESBWQCs and Uncertainty Concentrations to Sediment
Concentrations that are Toxic or Predicted to be Chronically Acceptable 54
5.4 Comparison of Dieldrin ESBWQCs to STORET, National Status and Trends, and
Corps of Engineers, San Francisco Bay Databases for Sediment Dieldrin 5-6
5.5 Limitations to the Applicability of ESBWQCs 5-10

Section 6
Sediment Benchmark Values: Application and Interpretation 6-1
6.1 Benchmarks 6.1
6.2 Considerations in the Application and Interpretation of ESBs 6-1
6.2.1 Relationship of ESBWQC to Expected Effects 6-1
6.2.2 Use of EqP to Develop Alternative Benchmarks 6-1
6.2.3 Influence of Unusual Forms of Sediment Organic Carbon 6-2
6.2.4 Relationship to Risks Mediated through
Bioaccumulation and Trophic Transfer 6-2
6.2.5 Exposures to Chemical Mixtures 6-2
6.2.6 Interpreting ESBs in Combination with Toxicity Tests 6-2
6.3 Summary 6-3
Section 7
References 7-1

Appendix A A-I

Appendix B B-I

Appendix C c-i
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Contents

Tables

Table 2-1. Dieldrin measured and estimated log10^Tow values 2-2

Table 2-2. Summary of KQC values for dieldrin derived from literature sorption isotherm data 24

Table 3 -1. Test-specific data for chronic sensitivity of freshwater and saltwater organisms to dieldrin 34

Table 3-2. Summary of freshwater and saltwater acute and chronic values, acute-chronic ratios, and
derivation of final acute values, final acute-chronic ratios, and final chronic values 3-5

Table 3-3. Results of the approximate randomization (AR) test for the equality of freshwater and
saltwater FAV distributions for dieldrin and AR test for the equality of benthic and
combined benthic and water column WQC FAV distributions 3-7

Table 4-1. Summary of tests with dieldrin-spiked sediment 4-2

Table 4-2. Water-only and sediment LC50 values used to test the applicability
of the EqP theory for dieldrin 4-5

Table 5 -1. Equilibrium partitioning sediment benchmarks (ESB s) for dieldrin
using the WQC FCV as the effect concentration 5-1

Table 5-2. Analysis of variance for derivation of confidence limits of the ESB WQCs for dieldrin 5-3

Table 5-3. Confidence limits of the ESBWQCs for dieldrin 5-3

Figures

Figure 1-1. Chemical structure and physical-chemical properties of dieldrin 1-3

Figure 2-1. Observed versus predicted partition coefficients for nonionic
organic chemicals 2-3

Figure 2-2. Organic carbon-normalized sorption isotherm for dieldrin and probability
plot of KQC from sediment toxicity tests 2-5

Figure 3 -1. Genus mean acute values from water-only acute toxicity tests using
freshwater species versus percentage rank of their sensitivity 3-2

Figure 3-2. Genus mean acute values from water-only acute toxicity tests
using saltwater species versus percentage rank of their sensitivity 3-3

Figure 3-3. Probability distribution of FAV difference statistics to compare water-only data from
freshwater versus saltwater and benthic versus WQC data 3-8

Figure 4-1. Percent mortalities of amphipods in sediments spiked with acenaphthene or phenanthrene,
endrin, or fluoranthene, and midge in sediments spiked with dieldrin or kepone relative
to interstitial water toxic units 4-3

Figure 4-2. Percent mortalities of amphipods in sediments spiked with acenaphthene or
phenanthrene, dieldrin, endrin, or fluoranthene, and midge in sediments spiked with
dieldrin relative to predicted sediment toxic units 44
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Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
Figure 5 -1. Predicted genus mean chronic values (PGMCV) calculated from water-only toxicity values
using freshwater species versus percentage rank of their sensitivity 54

Figure 5-2. Predicted genus mean chronic values (PGMCV) calculated from water-only toxicity
values using saltwater species versus percentage rank of their sensitivity 5-5

Figure 5-3. Probability distribution of concentrations of dieldrin in sediments from streams, lakes, and
estuaries in the United States from 1986 to 1990 from the STORET database compared with
the dieldrin ESBWQCs values 5-7

Figure 5-4. Probability distribution of concentrations of dieldrin in sediments from coastal and estuarine
sites from 1984 to 1989 as measured by the National Status and Trends Program 5-8

Figure 5 -5. Probability distribution of organic carbon-normalized sediment dieldrin concentrations
from the U.S. Army Corps of Engineers (1991) monitoring program of San Francisco Bay 5-9
IX
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Acknowledgments
Acknowledgments
Coauthors
Walter J. Berry* U.S. EPA, NHEERL, Atlantic Ecology Division,
Narragansett, RI
Robert M. Burgess U.S. EPA, NHEERL, Atlantic Ecology Division, Narragansett, RI
David J. Hansen HydroQual, Inc., Mahwah, NJ; Great Lakes Environmental
Center, Traverse City, MI (formerly with U.S. EPA)
Dominic M. Di Toro Manhattan College, Riverdale, NY; HydroQual, Inc., Mahwah, NJ
Laurie D. De Rosa HydroQual, Inc., Mahwah, NJ
Heidi E. Bell* U.S. EPA, Office of Water, Washington, DC
Mary C. Reiley U.S. EPA, Office of Water, Washington, DC
Frank E. Stancil, Jr. U.S. EPA, NERL, Ecosystems Research Division, Athens, GA
Christopher S. Zarba U.S. EPA, Office of Research and Development, Washington, DC
David R. Mount U.S. EPA, NHEERL, Mid-Continent Ecology Division, Duluth, MN
Robert L. Spehar U.S. EPA, NHEERL, Mid-Continent Ecology Division, Duluth, MN
Significant Contributors to the Development of the Approach and Supporting Science
Herbert E. Allen University of Delaware, Newark, DE
Gerald T. Ankley U.S. EPA, NHEERL, Mid-Continent Ecology Division, Duluth, MN
Christina E. Cowan The Procter & Gamble Co., Cincinnati, OH
Dominic M. Di Toro Manhattan College, Riverdale, NY; HydroQual, Inc., Mahwah, NJ
David J. Hansen HydroQual, Inc., Mahwah, NJ; Great Lakes Environmental
Center, Traverse City, MI (formerly with U.S. EPA)
Paul R. Paquin HydroQual, Inc., Mahwah, NJ
Spyros P. Pavlou Ebasco Environmental, Bellevue, WA
Richard C. Swartz Environmental consultant (formerly with U.S. EPA)
Nelson A. Thomas U.S. EPA, NHEERL, Mid-Continent Ecology Division,
Duluth, MN (retired)
Christopher S. Zarba U.S. EPA, Office of Research and Development, Washington, DC
Technical Support and Document Review
Patricia DeCastro Computer Sciences Corporation, Narragansett, RI
Robert A. Hoke E.I. DuPont deNemours and Company, Newark, DE
Scott D. Ireland U. S. EPA, Office of Water, Washington, DC
Heinz P. Kollig U.S. EPA, NERL, Ecosystems Research Division, Athens, GA
Tyler K. Linton Great Lakes Environmental Center, Columbus, OH
Robert L. Spehar U.S. EPA, NHEERL, Mid-Continent Ecology Division, Duluth, MN

* Principal U.S. EPA contact
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Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
XI
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Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
Executive Summary
This equilibrium partitioning sediment benchmark (ESB) document describes procedures to derive
concentrations of the insecticide dieldrin in sediment which are protective of the presence of
benthic organisms. The equilibrium partitioning (EqP) approach was chosen because it accounts
for the varying biological availability of chemicals in different sediments and allows for the
incorporation of the appropriate biological effects concentration. This provides for the derivation
of benchmarks that are causally linked to the specific chemical, applicable across sediments, and
appropriately protective of benthic organisms.

EqP theory holds that a nonionic chemical in sediment partitions between sediment organic
carbon, interstitial (pore) water and benthic organisms. At equilibrium, if the concentration in any
one phase is known, then the concentrations in the others can be predicted. The ratio of the
concentration in water to the concentration in organic carbon is termed the organic carbon
partition coefficient (^oc), which is a constant for each chemical. The ESB Technical Basis
Document (U.S. EPA, 2003a) demonstrates that biological responses of benthic organisms to
nonionic organic chemicals in sediments are different across sediments when the sediment
concentrations are expressed on a dry weight basis, but similar when expressed on a jj^g
chemical/g organic carbon basis (|j,g/goc). Similar responses were also observed across
sediments when interstitial water concentrations were used to normalize biological availability.
The Technical Basis Document further demonstrates that if the effect concentration in water is
known, the effect concentration in sediments on a M£/goc basis can be accurately predicted by
multiplying the effect concentration in water by the chemical's KQC.

EqP can be used to calculate ESBs for any toxicity endpoint for which there are water-only toxicity
data; it is not limited to any single effect endpoint. For the purposes of this document, the Final
Chronic Value (FCV) from the Water Quality Criterion (WQC) for dieldrin was used as the toxicity
benchmark. This value is intended to be the concentration of a chemical in water that is protective
of the presence of aquatic life. If an FCV is not available, a secondary chronic value (SCV) can be
substituted. The ESBWQC is derived by multiplying the FCV by the chemical's KQC, yielding the
concentration in sediment (normalized to organic carbon) that should provide the same level of
protection in sediment that the FCV provides in water. Ancillary analyses conducted as part of
this derivation suggest that the sensitivity of benthic/epibenthic organisms is not significantly
different from pelagic organisms; for this reason, the FCV and the resulting ESBWQC should be
fully applicable to benthic organisms. For dieldrin, this concentration is 12 (j^g dieldrin/goc for
freshwater sediments and 28 |J.g/goc for saltwater sediments. Confidence limits of 5.4 to 27 |J.g/goc
for freshwater sediments and 12 to 62 |J.g/goc for saltwater sediments were caluclated using the
uncertainty associated with the degree to which toxicity could be predicted by multiplying the
KQC and the water-only effects concentration. The ESBWQCs should be interpreted as chemical
concentrations below which adverse effects are not expected. At concentrations above the
ESBWQCs, effects may occur with increasing severity as the degree of exceedance increases. In
principle, above the upper confidence limit effects are expected if the chemical is bioavailable as
predicted by EqP theory. A sediment-specific site assessment would provide further information
on chemical bioavailability and the expectation of toxicity relative to the ESBWQCs and associated
uncertainty limits.

As discussed, while this document uses the WQC value, the EqP methodology can be used by
environmental managers to derive a benchmark with any desired level of protection, so long as
the water-only concentration affording that level of protection is known. Therefore, the resulting
benchmark can be species- or site-specific if the corresponding water-only information is
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Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
available. For example, if a certain water-only effects concentration is known to be protective for
an economically important benthic species, the organic carbon-normalized sediment concentration
protective for that benthic species could be derived using the effects concentration and the
partition coefficient. Such a benchmark might be considered as providing "site-specific
protection" for a species or endpoint, if the goal is to derive a benchmark for that particular site
or species. Another way to make an ESB site-specific would be to incorporate information on
unusual partitioning, if suspected, at the site (see U.S. EPA 2003b).

Consistent with the recommendations of EPA's Science Advisory Board, publication of these
documents does not imply the use of ESBs as stand-alone, pass-fail criteria for all applications;
rather, ESB exceedances could be used to trigger the collection of additional assessment data.
ESBs apply only to sediments having > 0.2% organic carbon by dry weight.

Tier 1 and Tier 2 ESB values were developed to reflect differing degrees of data availability and
uncertainty. Tier 1 ESBs have been derived for dieldrin in this document, and for the nonionic
organic insecticide endrin, metal mixtures, and polycyclic aromatic hydrocarbon (PAH) mixtures
in U.S. EPA (2003c, d, e). Tier 2 ESBs are reported in U.S. EPA (2003f).
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Glossary
Glossary of Abbreviations
ACR Acute-chronic ratio

ANOVA Analysis of variance

AR Approximate randomization

Cd Freely-dissolved interstitial water chemical concentration

Cm Total interstitial water chemical concentration (includes freely-dissolved and
DOC-complexed)

U.S. Army Corps of Engineers

Code of Federal Regulations

Clean Water Act

Dissolved organic carbon

Chemical concentration estimated to cause adverse affects to 50% of the test
organisms within a specified time period

United States Environmental Protection Agency

Equilibrium partitioning

Equilibrium partitioning sediment benchmark; for nonionic organics, this
term usually refers to a value that is organic carbon-normalized (more formally
ESBOC) unless otherwise specified

Organic carbon-normalized equilibrium partitioning sediment benchmark

Equilibrium partitioning sediment benchmark derived based on the Water
Quality Criteria for a specific chemical

Dry weight-normalized equilibrium partitioning sediment benchmark derived
based on the Water Quality Criteria for a specific chemical

Organic carbon normalized equilibrium partitioning sediment benchmark
derived based on the Water Quality Ctieria for a specific chemical

FACR Final acute-chronic ratio

FAV Final acute value

FCV Final chronic value

FDA U.S. Food and Drug Administration

foc Fraction of organic carbon in sediment

ERV Final residue value

GMAV Genus mean acute value

goc Gram organic carbon

HECD U.S. EPA, Health and Ecological Criteria Division
COE

CFR

CWA

DOC

EC50

EPA

EqP

ESB

ESBOC

ESBW
QC
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Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
HMAV

lUPAC

IWTU

-^DOC
LC50

LC50spc

LC50W

mDOC

NAS

NERL

NHEERL

NOAA

NOEC

OTIS

OEC

OST

PAH

PGMCV

PSTU

SCV

SMACR

STORET

TOC

WQC
Habitat mean acute value

International Union of Pure and Applied Chemistry

Interstitial water toxic unit

Dissolved organic carbon partition coefficient

Organic carbon-water partition coefficient

Octanol-water partition coefficient

Sediment-water partition coefficient

The concentration estimated to be lethal to 50% of the test organisms within a
specified time period

Organic carbon-normalized LC50 from sediment exposure

LC50 from water-only exposure

Measured DOC concentration

National Academy of Sciences

U.S. EPA, National Exposure Research Laboratory

U.S. EPA, National Health and Environmental Effects Research Laboratory

National Oceanographic and Atmospheric Administration

No observed effect concentration

National Technical Information Service

Organic carbon

Observed effect concentration

U.S. EPA, Office of Science and Technology

Poly cyclic aromatic hydrocarbon

Predicted genus mean chronic value

Predicted sediment toxic unit

Secondary chronic value

Standard deviation

Standard error

Species mean acute-chronic ratio

EPA's computerized database for STOrage and RETrieval of water-related data

Total organic carbon

Toxic unit

Water quality criteria
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Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
Section 1
Introduction
1.1 General Information

Toxic pollutants in bottom sediments of the
nation's lakes, rivers, wetlands, estuaries, and marine
coastal waters create the potential for continued
environmental degradation even where water column
concentrations comply with established WQC. In
addition, contaminated sediments can be a significant
pollutant source that may cause water quality
degradation to persist, even when other pollutant
sources are stopped. The absence of defensible
sediment ESBs makes it difficult to accurately assess
the extent of the ecological risks of contaminated
sediments and to identify, prioritize, and implement
appropriate cleanup activities and source controls.

As a result of the need for a procedure to assist
regulatory agencies in making decisions concerning
contaminated sediment problems, the EPA Office of
Science and Technology, Health and Ecological Criteria
Division (OST/HECD) established a research team to
review alternative approaches (Chapman, 1987). All of
the approaches reviewed had both strengths and
weaknesses, and no single approach was found to be
applicable for the derivation of benchmarks in all
situations (U.S. EPA, 1989a). The EqP approach was
selected for nonionic organic chemicals because it
presented the greatest promise for generating
defensible, national, numerical chemical-specific
benchmarks applicable across a broad range of
sediment types. The three principal observations that
underlie the EqP approach to establishing sediment
benchmarks are as follows:

1. The concentrations of nonionic organic chemicals
in sediments, expressed on an organic carbon
basis, and in interstitial waters correlate to
observed biological effects on sediment-dwelling
organisms across a range of sediments.

2. Partitioning models can relate sediment
concentrations for nonionic organic chemicals on
an organic carbon basis to freely-dissolved
chemical concentrations in interstitial water.

3. The distribution of sensitivities to chemicals of
benthic organisms is similar to that of water
column organisms; thus, the currently established
WQC, FCV or SCV can be used to define the
acceptable effects concentration of a chemical
freely-dissolved in interstitial water.

The EqP approach, therefore, assumes that
(1) the partitioning of the chemical between sediment
organic carbon and interstitial water is at or near
equilibrium; (2) the concentration in either phase can be
predicted using appropriate partition coefficients and
the measured concentration in the other phase
(assuming the freely-dissolved interstitial water
concentration can be accurately measured); (3)
organisms receive equivalent exposure from water-only
exposures or from any equilibrated phase: either from
interstitial water via respiration, from sediment via
ingestion or other sediment-integument exchange, or
from a mixture of both exposure routes; (4) for nonionic
chemicals, effect concentrations in sediments on an
organic carbon basis can be predicted using the
organic carbon partition coefficient (KQC) and effects
concentrations in water; (5) the FCV concentration is an
appropriate effects concentration for freely-dissolved
chemical in interstitial water; and (6) the ESBs derived
as the product of the KQC and FCV are protective of
benthic organisms. ESB concentrations presented in
this document are expressed as /j,g chemical/g sediment
organic carbon Gug/goc) and not on an interstitial water
basis because (1) interstitial water is difficult to sample
and (2) significant amounts of the dissolved chemical
may be associated with dissolved organic carbon; thus,
total chemical concentrations in interstitial water may
overestimate exposure.

Sediment benchmarks generated using the EqP
approach (i.e., ESBs) are suitable for use in providing
technical information to regulatory agencies because
they are:

1. Numerical values

2. Chemical specific

3. Applicable to most sediments

4. Predictive of biological effects

5. Protective of benthic organisms
1-1
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Introduction
ESBs are derived using the available scientific data
to assess the likelihood of significant environmental
effects to benthic organisms from chemicals in
sediments in the same way that the WQC are derived
using the available scientific data to assess the
likelihood of significant environmental effects to
organisms in the water column. As such, ESBs are
intended to protect benthic organisms from the effects
of chemicals associated with sediments and, therefore,
only apply to sediments permanently inundated with
water, to intertidal sediment, and to sediments
inundated periodically for durations sufficient to permit
development of benthic assemblages. ESBs should not
be applied to occasionally inundated soils containing
terrestrial organisms, nor should they be used to
address the question of possible contamination of
upper trophic level organisms or the synergistic,
additive, or antagonistic effects of multiple chemicals.
The application of ESBs under these conditions may
result in values lower or higher than those presented in
this document.

The ESB values presented herein are the
concentrations of dieldrin in sediment that will not
adversely affect most benthic organisms. It is
recognized that these ESB values may need to be
adjusted to account for future data. They may also
need to be adjusted because of site-specific
considerations. For example, in spill situations, where
chemical equilibrium between water and sediments
has not yet been reached, sediment chemical
concentrations less than an ESB may pose risks to
benthic organisms. This is because for spills,
disequilibrium concentrations in interstitial and
overlying water may be proportionally higher relative to
sediment concentrations. Research has shown that the
source or "quality" of total organic carbon (TOC) in the
sediment does not affect chemical binding (DeWitt et
al., 1992). However, the physical form of the chemical in
the sediment may have an effect. At some sites
concentrations in excess of an ESB may not pose risks
to benthic organisms, because the compound may be a
component of a paniculate, such as coal or soot, or
exceed solubility such as undissolved oil or chemical.
In these situations, an ESB would be overly protective
of benthic organisms and should not be used unless
modified using the procedures outlined in "Procedures
for the Derivation of Site-Specific Equilibrium
Partitioning Sediment Benchmarks (ESBs) for the
Protection of Benthic Organisms" (U.S. EPA, 2003b). If
the organic carbon has a low capacity (e.g., hair,
sawdust, hide), an ESB would be unperprotective. An
ESB may also be underprotective where the toxicity of
other chemicals are additive with an ESB chemical or
where species of unusual sensitivity occur at the site.

This document presents the theoretical basis and
the supporting data relevant to derivation of the ESBs
for dieldrin. The data that support the EqP approach
for deriving an ESB for nonionic organic chemicals are
reviewed by DiToro etal. (1991) andEPA(U.S. EPA,
2003a). Before proceeding through the following text,
tables, and calculations, the reader should consider
reviewing Stephanetal. (1985) and EPA (U.S. EPA,
1985, 2003a).

1.2 General Information: Dieldrin

Dieldrin is the common name of a persistent,
nonsystemic organochlorine insecticide used for
control of public health insect pests, termites, and
locusts. It is formulated for use as an emulsifiable
concentrate, as a wettable and dustable powder, or as a
granular product. Another source of dieldrin in the
environment other than from direct use of dieldrin
stems from the quick transformation of aldrin, also an
organochlorine pesticide, to dieldrin. Both dieldrin and
aldrin usage peaked in the mid-1960s and declined until
the early 1970s. All dieldrin products were canceled
(including aldrin) in a PR notice, 71-4, dated March 18,
1971. See also Code of Federal Regulations (CFR)
notice 37246, dated October 18,1974.

Structurally, dieldrin is a cyclic hydrocarbon
having a chlorine substituted methanobridge (Figure
1-1). It is similar to dieldrin, an endo-endo stereoisomer,
and has similar physicochemical properties, except that
it is more difficult to degrade in the environment
(Wang, 1988). Dieldrin is a colorless crystalline solid at
room temperature, with a melting point of about 176 °C
and specific gravity of 1.75 g/cc at 20 ° C. It has a vapor
pressure of 0.4 mPa (20 °C) (Hartley andKidd, 1987).

Dieldrin is considered to be toxic to aquatic
organisms, bees, and mammals (Hartley and Kidd,
1987). The acute toxicity of dieldrin ranges from genus
mean acute values (GMAVs) of 0.50 to 740 ^g/L for
freshwater organisms and 0.70 to 640 /ug/L for saltwater
organisms (Appendix A). Differences between dieldrin
concentrations causing acute lethality and chronic
toxicity in species acutely sensitive to this insecticide
are small; acute-chronic ratios (ACRs) range from 1.189
to 11.39 for three species (see Table 3-2 in Section 3.3).
Dieldrin bioconcentrates in aquatic animals from 400 to
68,000 times the concentration in water (U.S. EPA,
1980a). TheWQCfordieldrin(U.S.EPA, 1980a)is
1-2
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
derived using a Final Residue Value (FRY) calculated
using bioconcentration data and the Food and Drag
Administration (FDA) action level to protect
marketability of fish and shellfish; therefore, the WQC
is not "effects based." In contrast, the ESB for dieldrin
is effects based. It is calculated from the FCV derived
in Section 3.

1.3 Applications of Sediment Benchmarks

ESBs are meant to be used with direct toxicity
testing of sediments as a method of evaluation
assuming the toxicity testing species is sensitive to the
chemical of interest. They provide a chemical-by-
chemical specification of what sediment concentrations
are protective of benthic aquatic life. The EqP method
should be applicable to nonionic organic chemicals
with a Kow above 3.0. Examples of other chemicals to
which this methodology applies include dieldrin, metal
mixtures (Cd, Cu, Pb, Ni, Ag, Zn), andpolycyclic
aromatic hydrocarbon (PAH) mixtures.
MOLECULAR FORMULA
MOLECULAR WEIGHT
DENSITY
MELTING POINT
PHYSICAL FORM
VAPOR PRESSURE
CAS NUMBER:
TSL NUMBER:
COMMON NAME:
TRADE NAME:
Cl
Ci2H8Cl6O
380.93
1.75 g/cc (20°C)
176°C
Colorless crystal
0.40 mPa (20 °C)
60-57-1
IO 15750
Dieldrin (also dieldrine and ndieldrin)
Endrex (Shell); Hexadrin
CHEMICAL NAME: 1,2,3,4,10,10, hexachloro-lR, 4S, 4aS, 5R, 6R, 7S, 8SR, 8aR-
octahydro-6,7-epoxy-l, 4:5,8-dimethanoaphthalene (IUPAC)
Figure 1-1. Chemical structure and physical-chemical properties of dieldrin (from Hartley and Kidd, 1987).
1-3
-------
Introduction
For the toxic chemicals addressed by the ESB
documents Tier 1 (U.S. EPA, 2003c, d, e, and this
document) and Tier 2 (U. S. EPA, 2003f) values were
developed to reflect the differing degrees of data
availability and uncertainty. Tier 1 ESBs are more
scientifically rigorous and data intensive than Tier 2
ESBs. The minimum requirements to derive a Tier 1 ESB
include: (1) Each chemical's organic carbon-water
partition coefficient (KQC) is derived from the octanol-
water partition coefficient (KQW) obtained using the
SPARC (SPARC Performs Automated Reasoning in
Chemistry) model (Karickhoff et al., 1991) and the KQW-
Koc relationshipfromDiToroetal. (1991). This KQChas
been demonstrated to predict the toxic sediment
concentration from the toxic water concentration with
less uncertainty than KQC values derived using other
methods. (2) The FCV is updated using the most recent
toxicological information and is based on the National
WQC Guidelines (Stephanetal., 1985). (3)EqP
confirmation tests are conducted to demonstrate the
accuracy of the EqP prediction that the KQC multiplied
by the effect concentration from a water-only toxicity
test predicts the effect concentration from sediment
tests(Swartz, 1991;DeWittetal., 1992). Usingthese
specifications, Tier 1 ESBs have been derived for the
insecticide dieldrin in this document, the nonionic
organic insecticide endrin(U.S. EPA, 2003c), metals
mixtures (U.S. EPA, 2003d), and poly cyclic aromatic
hydrocarbon (PAH) mixtures (U.S. EPA, 2003e). In
comparison, the minimum requirements for a Tier 2 ESB
(U.S. EPA, 2003f) are less rigorous: (1) The KQW forthe
chemical that is used to derive the Koc can be from
slow-stir, generator column, shake flask, SPARC or
other sources. (2) FCVs can be from published or draft
WQC documents, the Great Lakes Initiative or
developed from AQUIRE. Secondary chronic values
(SCV) from Suter and Mabrey (1994) or other effects
concentrations from water-only tests can be also used.
(3) EqP confirmation tests are recommended, but are
not required forthe development of Tier 2 ESBs.
Because of these lesser requirements, there is greater
uncertainty in the EqP prediction of the sediment effect
concentration from the water-only effect concentration,
and in the level of protection afforded by Tier 2 ESBs.
Examples of Tier 2 ESBs for nonionic organic chemicals
are found inU.S. EPA(2003f).

1.4 Overview
Section 1 provides a brief review of the EqP
methodology and a summary of the physical-chemical
properties and aquatic toxicity of dieldrin. Section 2
reviews a variety of methods and data useful in
deriving partition coefficients for dieldrin and includes
the KQC recommended for use in deriving the dieldrin
ESBWQCs. Section 3 reviews aquatic toxicity data
contained in the dieldrin WQC document (U.S. EPA,
1980a) and new data that were used to derive the FCV
used in this document to derive the ESBWQCs
concentrations. In addition, the comparative
sensitivity of benthic and water column species is
examined, and justification is provided for use of the
FCV for dieldrin in the derivation of the ESBWQCs.
Section 4 reviews data on the toxicity of dieldrin in
sediments, the need for organic carbon normalization of
dieldrin sediment concentrations, and the accuracy of
the EqP prediction of sediment toxicity using KQC and
an effect concentration in water. Data from Sections 2,
3, and 4 are used in Section 5 as the basis for the
derivation of the ESBWQCs for dieldrin and its
uncertainty. The ESBWQCs for dieldrin are then
compared with three databases on dieldrin's
environmental occurrence in sediments. Section 6
concludes with the sediment benchmarks for dieldrin
and their application and interpretation. The references
cited in this document are listed in Section 7.
1-4
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
Section 2
Partitioning
2.1 Description of EqP Methodology

ESBs are the numerical concentrations of
individual chemicals that are intended to be predictive
of biological effects, protective of the presence of
benthic organisms, and applicable to the range of
natural sediments from lakes, streams, estuaries, and
near-coastal marine waters. For nonionic organic
chemicals, ESBs are expressed as /ug chemical/goc and
apply to sediments having >0.2% organic carbon by
dry weight. A brief overview follows of the concepts
that underlie the EqP methodology for deriving ESBs.
The methodology is discussed in detail in "Technical
Basis for the Derivation of Equilibrium Partitioning
Sediment Benchmarks (ESBs) forthe Protection of
Benthic Organisms: Nonionic Organics" (U.S. EPA,
2003a), hereafter referred to as the ESB Technical Basis
Document.

Bioavailability of a chemical at a particular
sediment concentration often differs from one sediment
type to another. Therefore, a method is necessary to
determine ESBs based on the bioavailable chemical
fraction in a sediment. For nonionic organic chemicals,
the concentration-response relationship for the
biological effect of concern can most often be
correlated with the interstitial water (i.e., pore water)
concentration (jug chemical/L interstitial water) and not
with the sediment chemical concentration (jug chemical/
g sediment) (Di Toro et al., 1991). From a purely
practical point of view, this correlation suggests that if
it were possible to measure the interstitial water
chemical concentration, or predict it from the total
sediment concentration and the relevant sediment
properties, then that concentration could be used to
quantify the exposure concentration for an organism.
Thus, knowledge of the partitioning of chemicals
between the solid and liquid phases in a sediment is a
necessary component for establishing ESBs. For this
reason, the methodology described below is called the
EqP method. As stated above, an ESB can be derived
using any given level of protection, in the following
example the FCV from the dieldrin WQC is used.

The ESB Technical Basis Document shows that
benthic species, as a group, have sensitivities similar to
all benthic and water column species tested (taken as a
group) to derive the WQC concentration for a wide
range of chemicals. The data showing this for dieldrin
are presented in Section 3.4. Thus, an ESB can be
established using the FCV, calculated based on the
WQC Guidelines (Stephan et al., 1985), as the accept-
able effect concentration in interstitial or overlying
water (see Section 5). The partition coefficient can then
be used to relate the interstitial water concentration
(i.e., the calculated FCV) to the sediment concentration
via the partitioning equation. This acceptable effect
concentration in sediment is anESBWQC.

An ESB is calculated as follows. Let FCV (jug/L) be
the acceptable concentration in water for the chemical of
interest, then compute an ESB using the partition
coefficient, Kp (L/kgsediment), between sediment and water
(2-1)
This is the fundamental equation used to generate the
ESBWQC. Its utility depends on the existence of a
methodology for quantifying Kp.

Organic carbon appears to be the dominant
sorption phase for nonionic organic chemicals in
naturally occurring sediments and, thus, controls the
bioavailability of these compounds in sediments.
Evidence for this can be found in numerous toxicity
tests, bioaccumulation studies, and chemical analyses
of interstitial water and sediments (Di Toro et al., 1991).
The evidence for dieldrin is discussed in this section
and in Section 4. The organic carbon binding of a
chemical in sediment is a function of that chemical's
KQC and the weight fraction of organic carbon in the
sediment (foc). The relationship is as follows
p Joeoc

It follows that
ESB
WQCOC
(2-2)
(2-3)
where ESB WQCOC is an ESB WQC on a sediment organic
carbon basis. For nonionic organics, the ESBWQC term
usually refers to a value that is organic carbon-
normalized (more formally ESBWQCOC) unless otherwise
specified.
2-1
-------
Partitioning
^Toc is not usually measured directly (although it
can be done; see Section 2.3). Fortunately, KQC is
closely related to the octanol-water partition
coefficient (KQW), which has been measured for many
compounds and can be measured very accurately. The
next section reviews the available information on the
Kr.,,, for dieldrin.
2.2
Determination of KOW for Dieldrin
Several approaches have been used to determine
KQW for the derivation of an ESBWQC, as discussed in
the ESBWQC Technical Basis Document. In an
examination of the literature, primary references were
found listing measured Iog10^ow values for dieldrin
ranging from 4.09 to 6.20 and estimated Iog10^ow
values ranging from 3.54 to 5.40 (Table 2-1). Karickhoff
and Long (1995,1996) established a protocol for
recommending KQW values for uncharged organic
chemicals based on the best available measured,
calculated, and estimated data. The recommended
logj 0^ow value of 5.3 7 for dieldrin from Karickhoff and
Long (1995) is used to derive the ESBWQC for dieldrin.
2.3 Derivation of Koc from Adsorption
Studies

Two types of experimental measurements of KQC
are available. The first type involves experiments
designed to measure the partition coefficient in particle
suspensions. The second type is from sediment
toxicity tests in which measurements of sediment
dieldrin, sediment TOC, and calculated freely-dissolved
concentrations of dieldrin in interstitial water were used
to compute KQC.
2.3.1 KQcfrom Particle Suspension Studies

Laboratory studies to characterize adsorption are
generally conducted using particle suspensions. The
high concentrations of solids and turbulent conditions
necessary to keep the mixture in suspension make data
interpretation difficult as a result of the particle
interaction effect. This effect suppresses the partition
coefficient relative to that observed for undisturbed
sediments (Di Toro, 1985;Mackay and Powers, 1987).

Based on analysis of an extensive body of
experimental data for a wide range of compound types
and experimental conditions, the particle interaction
model (Di Toro, 1985) yields the following relationship
for estimating Kp
focKoc
(24)
where m is the particle concentration in the suspension
(kg/L) and i>x, an empirical constant, is 1.4. The KQC is
given by
Iog10^oc = 0.00028 + 0.983
^ow
(2-5)
Figure 2-1 compares observed partition coefficient
data for the reversible component with predicted values
estimated with the particle interaction model (Equations
2-4 and 2-5) for a wide range of compounds (Di Toro,
1985). The observed partition coefficient for dieldrin
using adsorption data (Sharom et al., 1980) is
highlighted on this plot. The observed logwK of 1.68
reflects significant particle interaction effects. The
observed partition coefficient is more than an order of
Table 2-1. Dieldrin measured and estimated Iog10#ow values
Method
Measured
Measured
Measured
Measured
Measured
Estimated
Estimated
Logio&w
4.09
4.54
4.65
5.40
6.20
3.54
5.40
Reference
Ellington and Stancil, 1988
Brooke et al., 1986
DeKock and Lord, 1987
De Bruijn et al. , 1989
Briggs, 1981
Mabey etal., 1982
Karickhoff etal., 1989
2-2
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
magnitude lower than the value expected in the absence
of particle effects (i.e., logwK = 3.32 fromthe/ocXoc =
2100 L/kg). KQC was computed from Equation 2-5.

Several sorption isotherm experiments with particle
suspensions that provide an additional way to compute
KQC were found in a comprehensive literature search for
partitioning information for dieldrin (Table 2-2). The
KQC values derived from these data are lower than KQC
values from laboratory measurements of KQW. The
lower KQC can be explained from the particle interaction
effects. Partitioning in a quiescent setting would result
in less desorption and higher KQC. These data are
presented as examples of particle interaction if 100%
reversibility is assumed in the absence of desorption
studies and actual KQC cannot be computed. In the
absence of particle effects, KQC is related to KQW via
Equation 2-5. For logj 0-^ow = 5.37 (Karickhoff and
Long, 1995), this expression results in an estimate of
2.3.2 KQcfrom Sediment Toxicity Tests

Measurements of KQC were available from
sediment toxicity tests using dieldrin (Hoke and
Ankley, 1992). These tests used a sediment having an
average organic carbon content of 1.75% (Appendix B).
Dieldrin concentrations were measured in sediments
and in unfiltered interstitial waters, providing the data
necessary to calculate the partition coefficient for an
undisturbed bedded sediment. Note that data from
Hoke et al. (1995) were not used to calculate the
partition coefficient because either interstitial water was
not measured or free interstitial water could not be
ft,
41
-2
DIELDRIN
-2
Predicted loglftJOL/kg)
Figure 2-1. Observed versus predicted partition coefficients for nonionic organic chemicals, using Equation 2-4
(figure from Di Toro, 1985). Dieldrin datum is highlighted (Sharom et al., 1980).
2-3
-------
Partitioning
Table 2-2. Summary of A"oc values for dieldrin derived from literature sorption isotherm data
Observed Log^A^ (SD)a
4.20(0.14)
4.14(0.15)
4.10
n
4
3
1
Solids (SD)a
(g/L)
5.0
16.4(4.6)
100.0
Reference
Eye, 1968
Betsill, 1990
Briggs, 1981
SD = Standard deviation
correctly calculated. Since it is likely that organic
carbon complexing in interstitial water is significant for
dieldrin, organic carbon concentrations were also
measured in interstitial water. Figure 2-2 A is a plot of
the organic carbon-normalized sorption isotherm for
dieldrin, where the sediment dieldrin concentration (jj,g/
goc) is plotted versus the calculated free (dissolved)
interstitial water concentration Cwg/L). Using interstitial
water dissolved organic carbon (DOC) concentrations,
and assuming Kmc, the dissolved organic carbon
partition coefficient, is equal to KQC, the calculated free
interstitial water dieldrin concentration Cd (j^g/L)
presented in Figure 2-2 is given by
Q =
1 +
where Cm is the measured total interstitial water
concentration and mDOC is the measured DOC
concentration (U.S. EPA, 2000a). The data used to
make this plot are included in Appendix B. The line of
unity slope corresponding to the log10^Toc = 5.28,
derived from the dieldrin logj0^0w °f 5.37 from
Karickhoff and Long (1995), is compared with the data.
The data from the sediment toxicity tests fall on the line
of unity slope for logwKQC = 5.28 (Figure 2-2A).
A probability plot of the observed experimental
logwKQC values is shown in Figure 2-2B. The logl(jKQC
values were approximately normally distributed with a
mean of logwKQC = 5.32 and a standard error of the
mean (SE) of 0.109. This value is in agreement with
log10^Toc = 5.28, which was computed from the
Karickhoff and Long (1995) dieldrin log10^Tow of 5.37
(Equation 2-5).
2.4 Summary of Derivation of Koc for
Dieldrin

The KQC selected to calculate the ESBWQC for
dieldrin was based on the regression of Iog10iroc to
(2-6) logwKQW (Equation 2-5) using the dieldrin log10^Tow of
5.37 from Karickhoff and Long (1995). This approach,
rather than the use of the Koc from toxicity tests, was
adopted because the regression equation is based on
the most robust dataset available that spans a broad
range of chemicals and particle types, thus
encompassing a wide range of Kow and/oc values.
The regression equation yielded a logwKQC = 5.28.
This value is comparable to the logwKQC of 5.32
measured in the sediment toxicity tests.
2-4
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
IOQ000
10000
= i i \ i \ n\\ i i \ i 11 in i i i i 11 i i
= A
_ « Hoke and Anklev, 1992
"tb
-X 1000
O 100
10
0.1
I 10 100

Free Interstitial Water Concentration (|Jg/L)
1000
5.75
B 5.50
j£
^-' 5. 25
si 5.00
f 4.75
g 4.50
4.25
4.00
0
1 \ Mill 1 1 1 1 1 111!
_

-
-
-
-
-
i i iniiii i i 1 1 1 nn
I i 1

. • *

1 i 1
1 i 1
• *
*

i 1 1
MINIM 1 11(1111 1 1
* _

-
-
-
-
-
Mill 1 1 1 1 Illllll 1 1

11 10 20 50 80 90 99 99^9
Probability
Figure 2-2. Organic carbon-normalized sorption isotherm for dieldrin (A) and probability plot of #oc (B) from
sediment toxicity tests (Hoke and Ankley, 1992). The solid line represents the relationship predicted
with a Iog10#oc of 5.28.
2-5
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
Section 3
Toxicity of Dieldrin in
Water Exposures
3.1 Derivation of Dieldrin WQC

The example used in Section 2 for the EqP method
for derivation of the ESBWQC for dieldrin uses the WQC
FCV and KQC to estimate the maximum concentrations
of nonionic organic chemicals in sediments, expressed
on an organic carbon basis, that will not cause adverse
effects to benthic organisms. For this document, life-
stages of species classified as benthic are either
species that live in the sediment (infaunal) or on the
sediment surface (epibenthic) and obtain their food
fromeitherthe sediment or water column (U.S. EPA,
2000a). In this section, the FCV from the dieldrin WQC
document (U.S. EPA, 1980a) is revised using new
aquatic toxicity test data, and the use of this FCV is
justified as the appropriate effects concentration for the
derivation of dieldrin ESBWQCs.

3.2 Acute Toxicity in Water Exposures

A total of 116 standard acute toxicity tests with
dieldrin have been conducted on 28 freshwater species
from 21 genera (Figure 3 -1; Appendix A). Of these
tests, 38 were from 1 study with the guppy, Poecilla
reticulata (Chadwick and Kiigemagi, 1968). Some of
the values from this study have been omitted because
they came from tests using water from generator
columns that had not yet equilibrated. In some cases
this may have led to toxicity related to unmeasured
compounds, which the authors thought might have
skewed the results. Similar logic was used to choose
appropriate values in the WQC for dieldrin (U.S. EPA,
1980a). OverallGMAVsrangedfrom0.5to740^g/L.
Stoneflies, fishes, isopods, damselflies, glass shrimp,
and annelids were most sensitive; GMAVs for these
taxa range from 0.5 to 21.8 ^g/L. This database
contained 18 tests on 15 benthic species from 13 genera
(Figure 3-1; Appendix A).

Benthic organisms were both among the most
sensitive and the most resistant freshwater species to
dieldrin. GMAVs ranged from 0.5 to 740 ^g/L. Of the
epibenthic species tested, stoneflies, catfish, mayflies,
isopods, and glass shrimp were most sensitive; GMAVs
ranged from 0.5 to 20 ^g/L. Infaunal species tested
included only the oligochaete Lumbriculus variegatus
(LC50=21.8 Mg/L) and the stoneflies, Pteronarcys
californica (LC50=0.5 ,wg/L) andPtemnarcella badia
(LC50=0.5 Mg/L). The LC50 represents the chemical
concentrations estimated to be lethal to 50% of the test
organisms within a specified time period.

A total of 29 acute tests have been conducted on
22 saltwater species from 20 genera (Figure 3-1;
Appendix A). Overall GMAVs ranged from 0.70 to 640
A100 ^g/L.

3.3 Chronic Toxicity in Water
Exposures

Chronic toxicity tests have been conducted with
dieldrin using three freshwater fish and two saltwater
invertebrates. The fish include rainbow trout,
Oncorhynchus mykiss, the guppy, P. reticulata, and the
fathead minnow, Pimephales promelas. The
invertebrates include the mysid, Americamysis bahia,
and the polychaete worm, Ophryotrocha diadema
(Table 3-1). Both O. mykiss and A. bahia have benthic
life-stages.

Brooke (1993a) conducted an early life-stage test
with O. mykiss. There were reductions of 35% in
survival, 34% in weight, and 13% in length of the
3-1
-------
Toxicity of Dieldrin in Water Exposures
1000
100
<
ifl
3
a>
o
10
OJ
A Arthropods
• Other Invertebrates
• Fish and Amphibians
Orcanectes (A)
Gammams (A,X)
Simacepliatux
Daphnia
Bifo (
Palaemonetes (X)
Lepomis (J)

Iciahirus (XI
Ltmbriculus (A)
Pimephales (J)
Carassms (J,X)
' Ischnura (J)
Jllapia (J)
Oncorhyncus (J,X)
Micrapterns (X)
Claassenia (J)
Pteranacella (J)
Pleronarcys (J,N)
20 40 613 80
Percentage Rank of Freshwater Genera
100
Figure 3-1. Genus mean acute values from water-only acute toxicity tests using freshwater species versus
percentage rank of their sensitivity. Symbols representing benthic species are solid; those representing
water column species are open. A=adult, J=juvenile, N=naiads, X=unspecified life-stage.
survivors in the 0.95 ^g/L treatment relative to control
fish. O. mykiss were not significantly affected at
concentrations of 0.04 to 0.55 ,wg/L. The chronic value
based on these results is 0.7228 ,wg/L. Combined with
the 96-hour companion acute value of 8.23 /j,gfL
(Brooke, 1993a), the ACR for this species is 11.39
Mg/L (Table 3-2).

McCauley (1997) conducted an early life-stage test
with the fathead minnow, P. promelas. There was a
91 % reduction in survival in the 6.87 /-ig/L treatment
relative to control fish. Fathead minnows were not
significantly affected at concentrations of 0.38 to 3.02
Mg/L. There were no effects on growth or reproduction
recorded at any concentration tested. The chronic
value based on these results is 4.555 ^g/L. Two 96-
hour LC50 tests were also conducted in the same
dilution water as this test. One test was done with 30-
day-old juveniles (LC50=4.45 A
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
1000;
A. Arthropods
• Other Invertebrates
• Fish and Amphibians
Crassoslrfa (A)
100
Ophyryotmcha *(A)
Sphaemides (A)
4»
I
w
X
a
10
Cypriaodon (A)
Mysidopsis (A)
Micmmetrm £*.)
Morone (J)
Pagunia (A)
Gastffostetts (J)
Palatmon (A)
Mwf a (A)
(A)
Jlmiassonta (A)
Mensttia (J)
Cymalogeuitisr (J)

' Oncofkynchus (J)

f Anguilla (J)
' Penaeus (A)
0.1'
20 40 60 80

Percentage Rank of Saltwater Genera
100
Figure 3-2. Genus mean acute values from water-only acute toxicity tests using saltwater species versus percentage
rank of their sensitivity. Symbols representing benthic species are solid; those representing water
column species are open. Asterisk indicates greater than values. A=adult, J=juvenile.
these two values (5.415 ^g/L) was used in the
calculation of the ACR, which is 1.189 ,wg/L for this
species (Table 3-2).

Four freshwater chronic tests failed to meet the test
requirement of a measured concentration for use in
deriving WQC because there were no acceptable
companion acute tests from the same dilution water.
Therefore, the results of these tests were not used in
the calculation of the final ACR (FACR). Although an
ACR cannot be calculated from these data, the chronic
results are presented in Tables 3-1 and 3-2 to help
establish the chronic effect levels of dieldrin for these
species. One of these tests was an early life-stage test
conducted with O. mykiss (Chadwick and Shumway,
1969). There were reductions of 97% in survival and
36% in growth of the survivors in the 0.39 ,wg/L
treatment relative to control fish, and all fish died at 1.2
A*g/L dieldrin. Oncorhynchus mykiss were not
significantly affected at concentrations of 0.012 to 0.12
Aig/L and no progeny were tested. The other
freshwater chronic test that did not meet the "measured
3-3
-------
Toxicity of Dieldrin in Water Exposures
Table 3-1. Test-specific data for chronic sensitivity of freshwater and saltwater organisms to dieldrin
Habitat
Common Name, (life- Duration
Scientific Name Test stage) (days)
Freshwater Species
Rainbow trout, ELS W 100
Oncorhynchus
mykiss
Rainbow trout, ELS W 28
Oncorhynchus
mykiss

Guppy, LC W 195
Poecilia
reticulata
Guppy, LC W 195
Poecilia
reticulata
Guppy, LC W 195
Poecilia
reticulata
Fathead ELS W 30
minnow,
Pimephales
promelas
Saltwater Species
Mysid, LC E (J,A) 28
Americamysis
bahia
Polychaete LC I (L) 47
worm,
Ophryotrocha
diadema

Polychaete PLC I (A) 37
worm,
Ophryotrocha
diadema

Observed Effects Chronic
NOECs° OECs° (relative to Value
(Mg/L) Og/L) controls) Og/L)

0.012-0.12d °-39> 97-100% decrease 0.2163
1 2^ m survival,
36% reduction in
growth
0.04-0.55 0.95 35% decrease in 0.7228
survival,
13% reduction in
length, 34% in
weight
0.05,0.2, — — >1.0
i.od
0.2, 1.0,2. 5d — — >2-5

0225d 1 Od 42% reduction in >2.5
brood size

0.38-3.02 6.87 91% decrease in 4.555
survival

0.10,0.49 0.22, 24-58% decrease 0.7342
1.1, 1.6 in survival
0.1 0.3-13 34% decrease in 0.1732
survival,
37-99% reduction
in reproduction,
16-71% decrease
in progeny
survival
1.2 2.6-72 63% decrease in 1.766
survival,
57-100%
reduction in
reproduction
39-100% decrease
in progeny
survival
Reference

Chadwick
and
Shumway,
1969
Brooke,
1993a

Roelofs,
1971
Roelofs,
1971

Roelofs,
1971

McCauley,
1997

EPA,
1980b
Hooftman
and Vink,
1980

Hooftman
and Vink,
1980

"Test: LC = life-cycle, PLC = partial life-cycle, ELS = early life-stage.
Habitat: I = infaunal, E = epibenthic, W = water column. Life-stage: E = embryo, L = larval, J = juvenile, A = adult.
°NOECs = No observed effect concentration(s); OECs = Observed effect concentrations ).
Nominal, not measured.
eEstimated from graph.
Nominal (less than limit of analytical detection); all other values listed are measured values (there was good agreement between nominal
and measured) .
3-4

-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
Table 3-2. Summary of freshwater and saltwater acute and chronic values, acute-chronic ratios, and
derivation of the final acute values, final acute-chronic ratios, and final chronic values for dieldrin

Common Name,
Scientific Name
Acute Value
(96-hour)
(Mg/L)
Chronic
Value
Og/L)
Acute-Chronic
Ratio
(ACR)
Species Mean Acute-
Chronic Ratio
(SMACR)
Freshwater Species

Rainbow trout, 0 216 3 a
Oncorhynchus mykiss

Rainbow trout, 8.23 0.7228
Oncorhynchus mykiss

Guppy, >! Oa
Poecilia reticulata

Guppy, >25a
Poecilia reticulata

Guppy, 0.447a
Poecilia reticulata

Fathead minnow, 541 s'3 4.555
Pimephales promelas

Saltwater Species

Mysid, 4.5 0.7342
Americamysis bahia

Polychaete worm, >100 0.1732
Ophryotrocha diadema

Polychaete worm, > 100 1.766
Ophryotrocha diadema
11.39
1.189
6.129
>577.4
>56.63
11.39
1.189

6.129

>577.4
Not used in calculation of SMACR or FACR because acute value from matching dilution water is not available.
Acute value geometric mean of test with 30-day-old juveniles and test with <24-hour-old fish in the same dilution water (see text).
°Not used in calculation of SMACR or FACR because ACRs are greater than values. Also because the range of ACRs, if these are
included, is greater than a factor of 10.0, this species is much less acutely sensitive than the other species with available ACRs, and the
FAV derived with the other three ACRs is protective of this species (see text).
Freshwater
Final acute value = 0.2874 /j.g/L
Final acute-chronic ratio = 4.362
Final chronic value = 0.06589 ,ug/L
Saltwater
Final acute value = 0.6409 /j,g/L
Final acute-chronic ratio = 4.362
Final chronic value = 0.1469 /j,g/L
concentrations" criteria was a three-generation study
using the guppy, P. reticulata (Roelofs, 1971). Only
data from three tests with the first-generation fish were
included in Tables 3-1 and 3-2 because the test
organisms in the second- and third-generation tests
received some exposure prior to testing. There was no
effect on P. reticulata survival at any dieldrin
concentration in the first test (from 0.05 to 1.0 ^tg/L) or
in the second test (from 0.2 to 2.5 /-ig/L). In the third
test, mean brood size was reduced by 42% at 1.0 /-ig/L.
The 32% reduction in growth at 2.5 /ug/L was not
statistically significant. Because there were no
statistically significant differences from controls at the
highest concentration, the chronic value from this test
is considered to be >2.5
Saltwater A bahia exposed to dieldrin in a life-
cycle test (U.S. EPA, 1987b) were affected at
concentrations similar to those affecting the two
freshwater fish mentioned above. Survival of A. bahia
exposed to 0.22, 1.1, and 1.6 ^g/L was reduced by 24%,
35%, and 58%, respectively, relative to control
3-5
-------
Toxicity of Dieldrin in Water Exposures
A. bahia. There were no significant effects at 0.49
A100 /j,gfL for adults
and larvae. The FCV calculated using the ACRs
available from other species is protective of this
species.

The final acute value (FAV) derived from the
overall GMAVs(Stephanetal., 1985) forfreshwater
organisms was 0.2874 ,ug/L (Table 3-2). The FAV
derived from the overall GMAVs (Stephan et al., 1985)
for saltwater organisms was 0.6409 /ug/L (Table 3-2),
less than the acute value for the economically
important shrimp, P. duorarum. The available ACRs for
three species were 1.189 for P. promelas, 6.129 forA
bahia, and 11.39 for O. mykiss. The FACR, the
geometric mean of these three values, was 4.362. The
FCVs (Table 3 -2) for calculating the ESBWQCs for
dieldrin were calculated by dividing both the freshwater
and saltwater FAVby the FACR. The FCV for
freshwater organisms of 0.06589 ^g/L was the quotient
of the FAV of 0.2874 /^g/L and the FACR of 4.362.
Similarly, the FCV for saltwater organisms of 0.1469 ,wg/
L was the quotient of the FAV of 0.6409 /j.g/L and the
FACR of 4.362.
3.4 Applicability of the WQC as the
Effects Concentration for
Derivation of Dieldrin ESBWQCs

Use of the FCV as the effects concentration for
calculation of the ESBWQC assumes that benthic
(infaunal and epibenthic) species, as a group, have
sensitivities similar to all benthic and water column
species tested to derive the WQC concentration. Di
Toro et al. (1991) and the ESB Technical Basis
Document (U.S. EPA, 2003a) present data supporting
the reasonableness of this assumption, over all
chemicals for which there were published or draft WQC
documents. The conclusion of similar sensitivity was
supported by comparisons between (1) acute values for
the most sensitive benthic species and acute values for
the most sensitive water column species for all
chemicals, (2) acute values for all benthic species and
acute values for all species in the WQC documents
across all chemicals after standardizing the LC50
values, (3) FAVs calculated for benthic species alone
and FAVs calculated for all species in the WQC
documents, and (4) individual chemical comparisons of
benthic species versus all species. Only in this last
comparison were dieldrin-specific comparisons of the
sensitivity of benthic and all (benthic and water
column) species conducted. The following paragraphs
examine the data on the similarity of sensitivity of
benthic and all species for dieldrin used in this
comparison.

For dieldrin, benthic species account for 13 out of
21 genera tested in freshwater and 13 of 20 genera
tested in saltwater (Figures 3-1,3-2, Appendix A). An
initial test of the difference between the freshwater and
saltwater FAVs for all species (water column and
benthic) exposed to dieldrin was performed using the
approximate randomization (AR) method (Noreen, 1989).
The AR method tests the significance level of a test
statistic compared with a distribution of statistics
generated from many random subsamples. The test
statistic in this case was the difference between the
3-6
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
freshwater FAV, computed from the freshwater
(combined water column and benthic) species LC50
values, and the saltwater FAV, computed from the
saltwater (combined water column and benthic) species
LC50 values (Table 3-3). In the AR method, the
freshwater LC50 values and the saltwater LC50 values
(see Appendix A) were combined into one dataset. The
dataset was shuffled, then separated back so that
randomly generated "freshwater" and "saltwater" FAVs
could be computed. The LC50 values were separated
back such that the number of LC50 values used to
calculate the sample FAVs were the same as the number
used to calculate the original FAVs. These two FAVs
were subtracted and the difference used as the sample
statistic. This was done many times so that the sample
statistics formed a distribution representative of the
population of FAV differences (Figure 3-3 A). The test
statistic was compared with this distribution to
determine its level of significance. The null hypothesis
was that the LC50 values composing the saltwater and
freshwater databases were not different. If this were
true, the difference between the actual freshwater and
saltwater FAVs should be common to the majority of
randomly generated FAV differences. For dieldrin, the
test statistic occurred at the 16th percentile of the
generated FAV differences. Because the probability
was less than 95%, the hypothesis of no significant
difference in sensitivity for freshwater and saltwater
species was accepted (Table 3-3). Note that in both the
freshwater versus saltwater comparison and benthic
versus WQC comparison, greater than (>) values for
GMAVs (see Appendix A) were omitted from the AR
analysis. This resulted in one dieldrin saltwater benthic
organism being omitted.
Because freshwater and saltwater species showed
similar sensitivity, a test of difference in sensitivity was
performed for benthic and all (benthic and water
column species combined, hereafter referred to as
"WQC") organisms combining freshwater and saltwater
species, using the AR method. For this purpose, each
life-cycle of each test organism was assigned a habitat
(Appendix A) using the criteria observed by EPA (U.S.
EPA, 2003a). The test statistic in this case was the
difference between the WQC FAV, computed from the
WQC LC50 values, and the benthic FAV, computed from
the benthic organism LC50 values. This was slightly
different from the previous test for saltwater and
freshwater species in that saltwater and freshwater
species in the first test represented two separate
groups. In this test, the benthic organisms were a
subset of the WQC organisms set. In the AR method
for this test, the number of data points coinciding with
the number of benthic organisms was selected from the
WQC dataset and a "benthic" FAV was computed. The
original WQC FAV and the "benthic" FAV were then
used to compute the difference statistic. This was
done many times, and the resulting distribution was
representative of the population of FAV difference
statistics. The test statistic was compared with this
distribution to determine its level of significance. The
probability distribution of the computed FAV
differences is shown in Figure 3-3B. The test statistic
for this analysis occurred at the 68th percentile, and the
hypothesis of no difference in sensitivity was accepted
(Table 3-3). This analysis suggests that the FCVfor
dieldrin based on data from all tested species was an
appropriate effects concentration for benthic
organisms.
Table 3-3. Results of approximate randomization (AR) test for the equality of the freshwater and saltwater FAV
distributions for dieldrin and AR test for the equality of benthic and combined benthic and water column
(WQC) FAV distributions
Comparison
Habitat or Water Type'
a,b
AR Statistic0
Probability
Freshwater vs. Saltwater
Fresh (21) Salt (19) -0.334 16
Benthic vs. Water Column = Benthic
(WQC)
Benthic (26) WQC (40) 0.052 68
aValues in parentheses are the number of LC50 values used in the comparison.
Note that in both the freshwater vs. saltwater and benthic vs. WQC comparisons, greater than (>) values in Appendix A were omitted.
This resulted in one dieldrin saltwater benthic organism being omitted from the AR analysis.
CAR statistic = FAV difference between original compared groups.
Probability that the theoretical AR statistic < the observed AR statistic, given that the samples came from the same population.
3-7
-------
Toxicity of Dieldrin in Water Exposures
_ A
Freshwater vs Saltwater
I

i n 111111 i i \ i i i i in n i \ i i limn i r
o -
_ o
OCD
I I Illllil I I I I I III! I I I i I I I Illl I I I I I Illllll I I
B
- Benthic vs WQC
o
3
-7
111111 I I I (1(1111 1 I
Q
_O
i i mini i i i i inn i i i i i i i inn 11 i i mini i i
0.1 1 10 20 50 80 90 99 99.9
Probability
Figure 3-3. Probability distribution of FAV difference statistics to compare water-only data from freshwater versus
saltwater (A) and benthic versus WQC (B) data. The solid lines in the figure correspond to the FAV
differences measured for dieldrin.
3-8
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
Section 4
Actual and Predicted Toxicity of
Dieldrin in Sediment Exposures
4.1 Toxicity of Dieldrin in Sediments

The toxicity of dieldrin-spiked clean sediments was
tested with two freshwater species (an amphipod and a
midge) and two saltwater species (a polychaete and the
sand shrimp) (Table 4-1). Therefore, generalizations of
dieldrin's toxicity across species or sediments are
limited. The endpoint reported in these studies was
mortality (with the addition of dry weight in the midge
tests). Details about exposure methodology are
provided because sediment testing methodologies have
not been standardized in the way that water-only
toxicity test methodologies have. Data were available
from many experiments using both field and laboratory
sediments contaminated with mixtures of dieldrin and
other compounds. Data from these studies were not
included here because it was not possible to determine
the contribution of dieldrin to the observed toxicity.

The effects of sediment from three freshwater sites
in Minnesota spiked with dieldrin on the freshwater
amphipod, H. azteca, were studied by Hoke et al.
(1995). The TOC concentrations in the three sediments
were 1.7%, 2.9%, and8.7%, respectively. The
sediments were rolled in dieldrin-coated jars at 4°C
for 23 days. Mortality of H. azteca in these flow-
through tests was related to sediment exposure because
dieldrin concentrations in overlying water were
generally below detection limits. Given the
"nonstandard" dose response in many of the tests with
H. azteca, the LC50 values from these tests need to be
examined carefully. In several of these tests, toxicity
increased with concentration up to an intermediate
concentration and then decreased with further
increasing concentration. It may be that the amphipods
were avoiding the sediment in the higher concentrations
by coming out of the sediment, thereby limiting their
exposure (R. Hoke, E.I. DuPont deNemours and Co.,
Haskell Laboratory, Newark, DE, personal
communication). No dose-response relationship was
observed in the results from the definitive test with one
of the sediments (Airport Pond) or in the results from
further testing with this sediment using H. azteca
(Hoke et al., 1995). In at least one of the Airport Pond
sediment repeat experiments, mortality seemed to be
increasing at a concentration similar to that causing
50% mortality in the range-finder test, and then
dropped off. For this reason, only the Airport Pond
data from the range-finder test with this sediment are
used in the analysis of the toxicity data (Sections 4.1,
4.2, 4.3) and in Figures 4-1 and 4-2. The 10-day LC50
values increased with increasing TOC when dieldrin
concentration was expressed on a dry weight basis, but
increased only slightly with increasing organic carbon
when dieldrin concentration was expressed on an
organic carbon basis (Table 4-1). Hoke et al. (1995)
calculated organic carbon-normalized concentrations
based on TOC measured in individual treatments. This
leads to the apparent discrepancy between the
experiment mean TOC values and the organic carbon-
normalized concentrations reported in Tables 4-1 and 4-
2. LC50 values normalized to dry weight differed by a
factor of 19.4 (22.8 to 441.8
Mg/g) over a fivefold range of TOC. In contrast, the
organic carbon-normalized LC50 values differed by a
factor of 3.2 (1,322 to 4,272 Mg/goc).

The effects of dieldrin-spiked sediments on the
fresh water midge, C. tentans, were also reported by
Hoke et al. (1995). The TOC contents in the two
sediments were 1.5% and 2.0%. The sediments were
rolled in dieldrin-coated jars at 4 ° C for 30 days, stored
at 4 ° C for 60 days, and then rolled at 4 ° C for an
additional 30 days. LC50 values normalized to dry
weight differed by a factor of 3.0 (0.5 to 1.5 /-ig/g dry
weight). LC50 values normalized to organic carbon
differed by a factor of 2.7(35.1 to 95.3 Mg/goc). It is
not surprising that organic carbon normalization had
little effect, given the small range of TOC (1.5% to
2.0%).

The only saltwater experiments that tested
dieldrin-spiked sediments were conducted by McLeese
et al. (1982) and McLeese and Metcalfe (1980). These
began with clean sediments that were added to dieldrin-
coated beakers just before the addition of test
organisms. This is a marked contrast with tests using
4-1
-------
Actual and Predicted Toxicity of Dieldrin in Sediment Exposures
freshwater sediments spiked with dieldrin days or
weeks prior to test initiation. As a result, the dieldrin
concentrations in the sediment and overlying water
varied greatly over the course of these saltwater
experiments, and exposure conditions are uncertain. In
addition, transfer of test organisms to freshly prepared
beakers every 48 hours further complicates
interpretation of results of McLeese et al. (1982),
because exposure conditions changed several times
during the course of the test. McLeese et al. (1982)
tested the effects of dieldrin on the polychaete worm,
Nereis virens, in sediment with 2% TOC (17% sand
and 83% silt and clay) in 12-day toxicity tests. No
worms died in 13 ,wg/g dry weight sediment, the highest
concentration tested. McLeese and Metcalfe (1980)
tested the effects of dieldrin in sand with a TOC
content of 0.28% on the sand shrimp, Crangon
septemspinosa. The 4-day LC50 value was 0.0041 ,wg/g
dry weight sediment (1.46 Mg/goc)- Concentrations of
dieldrin in water overlying the sediment were 10 times
the LC50 in water. The authors concluded that
sediment-associated dieldrin contributed little to the
Table 4-1. Summary of tests with dieldrin-spiked sediment
Common Name,
Scientific Name
Freshwater Species
Amphipod,
Hyalella azteca
Amphipod,
Hyalella azteca

Amphipod,
Hyalella azteca

Midge,
Chironomus
tentans
Midge,
Chironomus
tentans
Saltwater Species
Polychaete
worm, Nereis
virens
Sand shrimp,
Crangon
septemspinosa

Method,a
Sediment TOC Duration
Source (%) (days) Response

Airport \.1° FT,M/10 LC50
Pond, MN
West 2.9b FT,M/10 LC50
Bearskin
Lake, MN
Pequaywa 8.7b FT, M/10 LC50
n Lake,
MN
Airport 2.0b FT, M/10 LC50
Pond, MN

Airport 1.5b FT, M/10 LC50
Pond, MN

17% sand, 2.0 R, M/12 LC50
83% silt
and clay6
Sand, wet- 0.28 R, M/4 LC50
sieved
between
1-2 mm
sieves6
Sediment Dieldrin
LC50 Interstitial
TTT^J- ,-
w ater
Dry wt OC LC50
(Mg/g) C"g/g) G"g/L) Reference

22.8 1,332° 54.3 Hokeetal.,
1995
43.4 1,322° 236 Hokeetal.,
1995

441.8 4,272° 492 Hokeetal.,
1995

1.5 95.3° 0.5d Hokeetal.,
1995

0.5 35.1° 0.2d Hokeetal.,
1995

>13 >650 — McLeese et
al., 1982

0.0041 1.46 — McLeese
and
Metcalfe,
1980

FT = flow-through; M = measured; R = renewed.
Mean reported TOC concentration.
cCalculated using individually measured TOC concentrations.
Interstitial water concentrations estimated from/oc, KQC, and measured sediment concentrations.
eClean sediment placed in dieldrin-coated beakers at beginning of exposure.
4-2
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
3?
m
tii
40
211
O Fndrin
• DM**,
A FluuruDUwiH.-
V Awciaphthene
0

f.lll
(1,1
lit
TIM.I
Inlerstitial Water Hiifc Units
Figure 4-1. Percent mortalities of amphipods in sediments spiked with acenaphthene or phenanthrene (Swartz, 1991),
endrin (Nebeker et al., 1989; Schuytema et al., 1989), or fluoranthene (Swartz et al., 1990; DeWitt et al.,
1992), and midge in sediments spiked with dieldrin (Hoke et al., 1995) or kepone (Adams et al., 1985)
relative to interstitial water units.
toxicity observed.

The need for organic carbon normalization of the
concentration of nonionic organic chemicals in
sediments is presented in the ESB Technical Basis
Document. For dieldrin, this need is supported by the
dieldrin-spiked toxicity tests described above,
particularly the experiments with H. azteca by Hoke et
al. (1995). Although it is important to demonstrate that
organic carbon normalization is necessary if
benchmarks are to be developed using the EqP
approach, it is fundamentally more important to
demonstrate that KQC and water-only effects
concentrations can be used to predict the effects
concentration for dieldrin and other nonionic organic
chemicals on an organic carbon basis for a range of
sediments. Evidence supporting this prediction for
dieldrin and other nonionic organic chemicals is
contained in the following sections.
4.2 Correlation Between Organism
Response and Interstitial Water
Concentration

One corollary of the EqP theory is that freely-
dissolved interstitial water LC50 values for a given
organism should be constant across sediments of
varying organic carbon content (U.S. EPA, 2003a).
Measured or estimated interstitial water values were
available from studies with two species (Table 4-2).
Data from tests with water column species were not
considered in this analysis. Hoke et al. (1995) found
that 10-day LC50 values for H. azteca based on
measured interstitial water concentrations differed by a
factor of 9.1 (54.3 to 491.6 ,wg/L) for three sediments
containing from 1.7% to 8.7% TOC. Therefore,
interstitial water-normalized LC50 values provided an
improvement over LC50 values for dieldrin expressed
on a dry weight basis which varied by a factor of 19.4
4-3
-------
Actual and Predicted Toxicity of Dieldrin in Sediment Exposures
(22.8 to 441.8 ,ug/g) (Table 4-1). The authors proposed
partitioning to DOC to explain the small disparity
between LC50 values based on interstitial water
dieldrin concentrations (Hokeetal., 1995). They found
that the 10-day LC50 values for C. tentans based on
predicted interstitial water concentrations (the
sediment concentration multiplied by the KQC; used
because measured concentrations were not available)
differed by a factor of 2.8 (0.18 to 0.50). This
variability was slightly less than that shown when dry
weight was used (factor of 3.0), but similar to that
shown when organic carbon normalization was used
(factor of 2.7).

A more detailed evaluation of the degree to which
the response of benthic organisms can be predicted
from toxic units (TUs) of substances in interstitial
water was made utilizing results from toxicity tests
with sediments spiked with a variety of nonionic
compounds, including acenaphthene and phenanthrene
(Swartz, 1991), dieldrin (Hoke et al., 1995), endrin
(Nebeker et al., 1989; Schuytema et al., 1989),
fluoranthene (Swartz et al., 1990; DeWitt et al., 1992),
and kepone (Adams et al., 1985) (Figure 4-1). The data
included in the following analyses were from tests
conducted at EPA laboratories or from tests that
utilized designs at least as rigorous as those conducted
at EPA laboratories. Tests with acenaphthene and
phenanthrene used two saltwater amphipods
(Leptocheirus plumulosus and Eohaustorius estuaris) and
saltwater sediments. Tests with fluoranthene used a
saltwater amphipod (Rhepoxynius abronius) and
saltwater sediments. Freshwater sediments spiked with
dieldrin and endrin were tested using the amphipod H.
azteca, and kepone-spiked sediments and dieldrin-spiked
sediments were tested using the midge, C. tentans.

Figure 4-1 presents the percent mortalities of the
benthic species tested in individual treatments for each
chemical versus interstitial water TUs (IWTUs) for all
sediments tested with the following caveat for dieldrin.
Only the C. tentans Airport Pond data are used for
dieldrin, in part due to difficulties with the H. azteca
mortality results, as previously discussed (Figure 4-1).
100
O Endrin
* DfcUrfn
O ITuaianthrvttu
A Hutwanttene
I n
L
cuii
04 1 10

1'ivdictol Sediment Toxic Units With Uncertainty Bars
too
Figure 4-2. Percent mortalities of amphipods in sediments spiked with acenaphthene or phenanthrene (Swartz, 1991),
dieldrin (Hoke et al., 1995), endrin (Nebeker et al., 1989; Schuytema et al., 1989), or fluoranthene (Swartz
et al., 1990; DeWitt et al., 1992), and midge in sediments spiked with dieldrin (Hoke et al., 1995) relative to
predicted sediment toxic units.
4-4
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
Because DOC plays a significant role in the
partitioning of dieldrin, the free interstitial water
concentration is calculated using Equation 2-6 with the
DOC values reported by Hoke and Ankley (1992) and
the nominal interstitial water concentrations for
Airport Pond sediments. The log10^TDOC of 4.43 is taken
from Kosian et al. (1995). This same approach was
used for Pequaywan and West Bearskin Lakes data, with
the poor results most likely due to the effects of DOC
complexation (Hoke et al., 1995). Because only
nominal interstitial water values are available, the
dieldrin data shown in Figure 4-1 are presented to
demonstrate the concept that interstitial water
concentrations can be used to predict the response of an
organism to a chemical that is not sediment specific.

IWTUs are the concentration of the chemical in
interstitial water (/-ig/L) divided by the water-only LC50
(jWg/L). Theoretically, 50% mortality should occur at
one IWTU. At concentrations below one IWTU there
should be less than 50% mortality, and at
concentrations above one IWTU there should be greater
than 50% mortality. Figure 4-1 shows that, at
concentrations below one IWTU, mortality was
generally low and increased sharply at approximately
one IWTU. Therefore, this comparison supports the
concept that interstitial water concentrations can be
used to make a prediction, that is not sediment specific,
of the response of an organism to a chemical. This
interstitial water normalization was not used to derive
the FSB in this document because of the complexation
of nonionic organic chemicals with interstitial water
DOC (Section 2) and the difficulties of adequately
sampling interstitial waters.

4.3 Tests of the Equilibrium Partitioning
Prediction of Sediment Toxicity

Sediment benchmarks derived using the EqP
approach utilize partition coefficients and FCVs from
updated or final WQC documents to derive the ESBWQC
Table 4-2. Water-only and sediment LC50 values used to test the applicability of the EqP theory for dieldrin

Common
Name,
Scientific
Name
Amphipod,
Hyalella
azteca
Amphipod,
Hyalella
azteca
Amphipod,
Hyalella
azteca
Midge,
Chironomus
tentans
Midge,
Chironomus
tentans

Water-
Method, only
Duration LC50
(days) Og/L)
FT,M/10 7.3
FT,M/10 7.3
FT,M/10 7.3
FT,M/10 1.1

FT,M/10 1.1

Interstitial
Water
LC50 TOC
(Mg/L) (%)
54.3 1.7°
236.1 2.9°
491.6 8.7°
0.50f 2.0°

0.18f 1.5°
Dieldrin Sediment
LCSOs
Dry Predicted
Wt. OC LC50
(Mg/g) G"g/g) (Mg/goc)
22.8 l,332d l,391e
43.4 l,332d l,391e
441.8 4,272d l,391e
1.5 95.3d 210e

0.5 35. ld 210e

Ratio:
Actual/
Predicted
LC50
0.95
0.95
3.1
0.45

0.17

Reference
Hoke et al.,
1995
Hoke et al.,
1995
Hoke et al.,
1995
Hoke et al.,
1995
Hoke et al.,
1995

aFT = flow-through; M = measured.
bPredicted LC50 Og/goc) = water-only LC50 Og/L) x KQC (L/kgoc) x 1 kgoc/1000 goc; where KOC = W52
cMean reported TOC concentration.
Calculated using individually measured TOC concentrations.
eCalculated using mean measured TOC concentrations.
Interstitial water concentrations estimated from /"„„, K^m and measured sediment concentrations.
J UC' UC'
4-5
-------
Actual and Predicted Toxicity of Dieldrin in Sediment Exposures
concentration that are protective of benthic organisms.
The partition coefficient KQC is used to normalize
sediment concentrations and predict biologically
available concentrations across sediment types. The
data required to test the organic carbon normalization
for dieldrin in sediments were available for two benthic
species. Data from tests with water column species
were not included in this analysis. Testing of this
component of the ESBWQC derivation required three
elements: (1) a water-only effect concentration, such as
a 10-day LC50 value, in /-ig/L; (2) an identical sediment
effect concentration on an organic carbon basis in ,wg/
goc; and (3) a partition coefficient for the chemical,
KQC, in L/kgoc. This section presents evidence that the
observed effects concentration in sediments (2) can be
predicted utilizing the water-only
effect concentration (1) and the partition coefficient (3).

Predicted sediment 10-day LC50 values from
dieldrin-spiked sediment tests with H. azteca (Hoke et
al., 1995) were calculated (Table 4-2) using the Iog10
KQC value of 5.28 from Section 2 of this document and
the water-only LC50 value (7.3 /-ig/L). Ratios of actual
to predicted sediment LC50 values for dieldrin
averaged 1.4 (range 0.95 to 3.1) in tests with three
sediments. Similarly, predicted sediment 10-day LC50
values for dieldrin-spiked sediment tests with C.
tentans (Hoke et al., 1995) were calculated using the
Iog10^roc of 5.28 and a 10-day water-only LC50 value of
1.1 /-ig/L (Table 4-2). Ratios of predicted to actual
sediment LC50 values for dieldrin averaged 0.28 (range
0.17 to 0.45) in tests with two sediments. The
overall geometric mean ratio for both species was 0.73.

A more detailed evaluation of the accuracy and
precision of the EqP prediction of the response of
benthic organisms can be made using the results of
toxicity tests with amphipods exposed to sediments
spiked with acenaphthene, phenanthrene, dieldrin,
endrin, or fluoranthene. The data included in this
analysis were from tests conducted at EPA laboratories
or from tests that utilized designs at least as rigorous
as those conducted at EPA laboratories. Data from the
kepone experiments were not included because the
recommended KQVf for kepone obtained from Karickhoff
and Long (1995) was evaluated using only one
laboratory measured value, whereas the remaining
chemical KQVf values are recommended based on
several laboratory measured values. Swartz (1991)
exposed the saltwater amphipods E. estuarius and L.
plumulosus to acenaphthene in three marine sediments
having organic carbon contents ranging from 0.82% to
4.2% and to phenanthrene in three marine sediments
having organic carbon contents ranging from 0.82% to
3.6%. Swartz et al. (1990) exposed the saltwater
amphipod R. abronius to fluoranthene in three marine
sediments having 0.18%, 0.31%, and 0.48% organic
carbon. Hoke et al. (1995) exposed the amphipod H.
azteca to three dieldrin-spiked freshwater sediments
having 1.7 %, 2.9 %, and 8.7% organic carbon, and also
exposed the midge C. tentans to two freshwater
dieldrin-spiked sediments having 2.0% and 1.5 %
organic carbon. Nebeker et al. (1989) and Schuytema
et al. (1989) exposed H. azteca to three endrin-spiked
sediments having 3.0 %, 6.1 %, and 11.2% organic
carbon. Figure 4-2 presents the percent mortalities of
amphipods in individual treatments of each chemical
versus predicted sediment TUs (PSTUs) for each
sediment treatment. PSTUs are the concentration of
the chemical in sediments (Atg/goc) divided by the
predicted sediment LC50 (i.e., the product of KQC and
the 10-day water-only LC50, expressed in ,wg/goc). In
this normalization, 50% mortality should occur at one
PSTU. Figure 4-2 shows that at concentrations below
one PSTU mortality was generally low and increased
sharply at one PSTU. Therefore, this comparison
supports the concept that PSTUs also can be used to
make a prediction, that is not sediment specific, of the
response of an organism to a chemical. The means of
the LC50 values for these tests calculated on a PSTU
basis were 1.55 for acenaphthene, 0.73 for dieldrin,
0.33 for endrin, 0.75 for fluoranthene, and 1.19 for
phenanthrene. The mean value for the five chemicals
was 0.80. The fact that this value is so close to the
theoretical value of 1.0 illustrates that the EqP method
can account for the effects of different sediment
properties and properly predict the effects
concentration in sediments using the effects
concentration from water-only exposures.

Data variations in Figure 4-2 reflect inherent
variability in these experiments and phenomena that
have not been accounted for in the EqP model. The
uncertainty of the model is calculated in Section 5.2 of
this document. There is an uncertainty of
approximately +2. The error bars shown in Figure 4-2
are computed as +1.96 X (ESBWQC uncertainty). The
value of 1.96 is the t statistic, which provides a 95 %
confidence interval around the ESBWQCs.
4-6
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
Section 5
Benchmarks Derivation for Dieldrin
5.1 Derivation of ESB s
WQC
The WQC FCV (see Section 3), without an
averaging period or return frequency, can be used to
calculate the ESBWQCs because the concentration of
contaminants in sediments is probably relatively stable
over time. Thus, exposure to sedentary benthic species
should be chronic and relatively constant. This
contrasts with the situation in the water column, where
a rapid change in exposure and exposures of limited
durations can occur from fluctuations in effluent
concentrations, from dilutions in receiving waters, or
from the free-swimming or planktonic nature of water
column organisms. For some particular uses of the
ESBWQCs, it may be appropriate to use the area! extent
and vertical stratification of contamination at a
sediment site in much the same way that averaging
periods or mixing zones are used with WQC.

The FCV is the value that should protect 95% of
the tested species included in the calculation of the
WQC from chronic effects of the substance. The FCV
is the quotient of the FAV and the FACR for the
substance. The FAV is an estimate of the acute LC50 or
EC50 concentration of the substance corresponding to
a cumulative probability of 0.05 for the genera from
eight or more families for which acceptable acute tests
have been conducted on the substance. The EC50
represents the chemical concentration estimated to
cause effects to 50% of the test organisms within a
specified time period. The ACR is the mean ratio of
acute to chronic toxicity for three or more species
exposed to the substance that meets minimum database
requirements. For more information on the calculation
of ACRs, FAVs, and FCVs, see Section 3 of this
document and the WQC Guidelines (Stephan et al.,
1985). The FCV used in this document differs from the
FCV in the dieldrin WQC document (U.S. EPA, 1980a)
because it incorporates recent data not included in that
document and omits some data that do not meet the
data requirements of the 1985 WQC Guidelines.

The EqP method for calculating ESBWQCs is based
on the following procedure (also described in Section
2.1). If the FCV O-tg/L) is the chronic concentration
from the WQC for the chemical of interest, then the
ESBWQC Oug/g sediment) are computed using the
partition coefficient, Kp (L/g sediment), between
sediment and interstitial water
(5-1)
The organic carbon partition coefficient, KQC, can be
substituted for Kp, because organic carbon is the
predominant sorption phase for nonionic organic
chemicals in naturally occurring sediments (salinity,
grain size, and other sediment parameters have
inconsequential roles in sorption; see Sections 2.1 and
4.3). Therefore, on a sediment organic carbon basis,
the organic carbon-normalizedESBWQCs (i.e.,
(5-2)
ESBWQCOC~^OCFCV
Because KQC is presumably independent of sediment
type for nonionic organic chemicals, so too are the
ESBWQCOC. Table 5-1 contains the calculated values of
the dieldrin ESBWQCs.
Table 5-1. Equilibrium partitioning sediment benchmarks (ESBWQCs) for dieldrin using the WQC FCV as the
effect concentration
Type of Water Body
Freshwater
Saltwater
(L/kg)
5.37
5.37
(L/kg)
5.28
5.28
FCV
Og/L)
0.06589
0.1469
ESGoc
(Mg/goc)
12a
28b
aESBWQCOC = (105 28 L/kgoc) x (10-3 kgoc/goc) x (0.06589 //g dieldrin/L) = 12 //g dieldrin/g^,.
bESBWQCOC = (105 28 L/kg^,) x (10-3 kgoc/goc) x (0.1469 //g dieldrin/L) = 28 ,ug dieldrin/goc.
5-1
-------
Derivation of Dieldrin ESBWQCs
The ESBWQCOC is applicable to sediments withfoc
>0.2%. For sediments with/oc <0.2%, organic carbon
normalization and the resulting ESBWQCsdo not apply.

Because organic carbon is the factor controlling
the bioavailability of nonionic organic compounds in
sediments, ESBWQCs have been developed on an
organic carbon basis, not on a dry weight basis. When
the chemical concentrations in sediments are reported
as dry weight concentrations and organic carbon data
are available, it is best to convert the sediment concen-
trations to /ug chemical/goc. These concentrations can
then be directly compared with the ESBWQCs values.
This facilitates comparisons between the ESBWQCs and
field concentrations relative to identification of hot
spots and the degree to which sediment concentrations
do or do not exceed the ESBWQCs values. The
conversion from dry weight to organic carbon-
normalized concentration can be done using the
following formula

A< (%TOC-H 100)

For example, the ESBWQC , wt value for freshwater
sediments with 1% organic carbon is 0. 12
c * 1 % TOC - 100 = 0.12 Mg/gdrywt
This method is used in the analysis of the STORET
data in Section 5.4.
5.2 Uncertainty Analysis

Some of the uncertainty of the dieldrin ESBWQCs
can be estimated from the degree to which the available
sediment toxicity data are explained using the EqP
model, which serves as the basis for the ESBs. In its
assertion, the EqP model holds that (1) the
bioavailability of nonionic organic chemicals from
sediments is equal on an organic carbon basis and (2)
the effects concentration in sediment G"g/goc) can be
estimated from the product of the effects concentration
from water-only exposures (e.g., FCV (^g/L)), and the
partition coefficient, KQC (L/kg). The uncertainty
associated with the ESBWQCs can be obtained from a
quantitative estimate of the degree to which the
available data support these assertions.

The data used in the uncertainty analysis are from
the water-only and sediment toxicity tests that were
conducted to fulfill the minimum database requirements
for development of the ESBWQC (see Section 4.3 and the
ESB Technical Basis Document). These freshwater and
saltwater tests span a range of chemicals and
organisms, they include both water-only and sediment
exposures, and they are replicated within each
chemical-organism-exposure media treatment. These
data were analyzed using an analysis of variance
(ANOVA) to estimate the uncertainty (i.e., the variance)
associated with varying the exposure media and that
associated with experimental error. If the EqP model
were perfect then there would be experimental error
only. Therefore, the uncertainty associated with the
use of EqP is the variance associated with varying
exposure media.

The data used in the uncertainty analysis are
illustrated in Figure 4-2. The data for dieldrin are
summarized in Appendix B. Only data from Hoke et al.
(1995), as listed in Appendix B, were used in the
uncertainty analysis because of mortality problems
with H. azteca from Airport Pond as discussed in
Sections 4.1 and 4.2. Data from Hoke and Ankley
(1992), which used only Airport Pond sediments, have
been used solely to compute partitioning. LC50 values
for sediment and water-only tests were computed from
these data. The EqP model can be used to normalize
the data in order to put it on a common basis. The
LC50 values from water-only exposures (LC50W; ^g/L)
are related to the organic carbon-normalized LC50
values from sediment exposures (LC50S oc; ^g/goc) via
the partitioning equation
(5-3)
5-2
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
As mentioned above, one of the assertions of the EqP
model is that the toxicity of sediments expressed on an
organic carbon basis equals the toxicity in water-only
tests multiplied by the KQC. Therefore, both LC50S oc
andKQC x LC50W are estimates of the true LC50QC for
each chemical-organism pair. In this analysis, the
uncertainty of KQC is not treated separately. Any error
associated with KQC will be reflected in the uncertainty
attributed to varying the exposure media.

In order to perform an analysis of variance, a model
of the random variations is required. As discussed
above, experiments that seek to validate Equation 5-3
are subject to various sources of random variations. A
number of chemicals and organisms have been tested.
Each chemical-organism pair was tested in water-only
exposures and in different sediments. Let a represent
the random variation due to this source. Also, each
experiment was replicated. Let e represent the random
variation due to this source. If the model were perfect,
there would be no random variations other than those
from experimental error, which is reflected in the
replications. Hence, a represents the uncertainty due
to the approximations inherent in the model and e
represents the experimental error. Let (aa)2 and (ae)2 be
the variances of these random variables. Let i index a
specific chemical-organism pair. Letj index the
exposure media, water-only, or the individual
sediments. Let k index the replication of the experiment.
Then the equation that describes this relationship is
(5-4)
where ln(LC50iJ k) is either ln(LC50w)orln(LC50s oc),
corresponding to a water-only or sediment exposure,
and ^ is the population of ln(LC50) for chemical-
organism pair i. The error structure is assumed to be
lognormal, which corresponds to assuming that the
errors are proportional to the means (e.g., 20%), rather
than absolute quantities (e.g., 1 ^g/goc). The statistical
problem is to estimate ^ (oa)2, and (o£)2. The maximum
likelihood method is used to make these estimates
(U.S. EPA, 2003a). The results are shown in Table 5-2.
The last line of Table 5-2 is the uncertainty associated
with the ESBWQCs; i.e., the variance associated with the
exposure media variability.

The confidence limits for the ESBWQCs are
computed using this estimate of uncertainty for the
ESBWQCs. For the 95% confidence interval limits, the
significance level is 1.96 for normally distributed errors.
Hence,

ln(ESBWQCOC)uppER = ln(ESBWQCOC) + 1.96aESBwQC (5-5)

ln(ESBWQCOC)LOWER = ln(ESBWQCOC)- 1.960^^ (5-6)

The confidence limits are given in Table 5-3.

The ESBWQCOC are applicable to sediments withfoc
>0.2%. For sediments with/QC <0.2%, organic carbon
normalization and ESBWQCsdo not apply.
Table 5-2. Analysis of variance for derivation of confidence limits of the ESBs for dieldrin
Source of Uncertainty
Parameter
Value Cwg/goc)
Exposure media

Replication

ESG Sediment Guideline
OESG
0.41

0.29

0.41
Table 5-3. Confidence limits of the ESBWQCs for dieldrin
Type of Water Body
ESGoc
Cwg/goc)
95% Confidence Limits (//g/goc)
Lower
Upper
Freshwater

Saltwater
12

28
5.4

12
27

62
5-3
-------
Derivation of Dieldrin ESBWQCs
5.3 Comparison of Dieldrin ESB and
Uncertainty Concentrations to
Sediment Concentrations that are
Toxic or Predicted to be Chronically
Acceptable
Insight into the magnitude of protection afforded
to benthic species by ESBWQC concentrations and 95%
confidence intervals can be inferred using effect
concentrations from toxicity tests with benthic species
exposed to sediments spiked with dieldrin and sediment
concentrations predicted to be chronically safe to
organisms tested in water-only exposures (Figures 5-1
and 5-2). The effect concentrations in sediments are
predicted from water-only toxicity data and KQC values
(see Section 4). Chronically acceptable concentrations
are extrapolated from GMAVs from water-only, 96-hour
lethality tests using the FACR. These two predictive
100000
10000
o
I
O
I
T3
1000
100
10
- Water-onlvt ests: PGMCV
D^ Arthropods A
D" Other Ir&ertebrates A
n* Bish and Amphibians
D
E Sediment 10-day LC50SOC A A
I P* C. Sntans = 57.8 ug/goc
range 2 tests = 35 . 1 to 95 .3 T
°* H. azteca = 1959 ^tg/goc „
range 3 tests = 1322 to 4272 ]_
:
-
-
:
-
-
-

i
A A A

A •
. ° ° A
O
O
t
upper ^7 UP/O
FSR • 0_9 II o/o
WQC' H~ H-o'oou
lower' ^ 4 LICT/CT

02
04
06
08
100
Percentage Rank of Freshwater Genera
Figure 5-1. Predicted genus mean chronic values (PGMCV) calculated from water-only toxicity values (Equation 5-
7; Appendix A) using freshwater species versus percentage rank of their sensitivity. Lines indicate the
freshwater dieldrin ESBWQC ± 95% confidence limits. Solid symbols are benthic genera; open symbols
are water column genera. Sediment 10-day LC50SOC values (calculated from Hoke et al., 1995; see
Table 4-1) for the amphipods C. teutons (H) and H. azteca (•£) are provided for comparison. Error bars
around the LC50S oc values indicate the observed range of LCSOs.
5-4
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
values are used to estimate chronically acceptable
sediment concentrations (predicted genus mean
chronic value, PGMCV) for dieldrin from GMAVs
(Appendix A), the FACR (Table 3-2), and the ^oc
(Table 5-1)

PGMCV= (GMAV-ACR) KQC (5-7)

Each PGMCV for fishes and amphibians,
arthropods, or other invertebrates tested in water was
plotted against the percentage rank of its sensitivity.
Results fromtoxicity tests withbenthic organisms
exposed to sediments spiked with dieldrin (Table 4-1;
Appendix B) are placed in the PGMCV rank appropriate
to the test-specific effect concentration. For example,
the mean 10-day LC50S oc for C. tentans, 57.8 ,wg/goc, is
placed between the PGMCV of 25.0 Mg/goc for the
stonefly, Claassenia, and the PGMCV of 153 ,wg/goc f°r
the fish, Micropterus. Therefore, the LC50 or other
effect concentrations are intermingled in this figure
with concentrations predicted to be chronically safe.
Care should be taken by the reader in interpreting these
data with dissimilar endpoints. The following
discussion of ESBWQCs, organism sensitivities, and
PGMCVs is not intended to provide accurate
predictions of the responses of taxa or communities of
101)001)
10000
>
.a
a
|
O
a
S
a
HO
ai
1000
100
Water-only tests: PGMCV

A Arthropods
• Other Invertebrates
• Fish and Amphibians
* *
upper 62

ESBWQC: 28 (ig/goc

lower: l
60
m
100
Percentage Rank of Saltwater Genera
Figure 5-2. Predicted genus mean chronic values (PGMCV) calculated from water-only toxicity values (Equation
5-7; Appendix A) using saltwater species versus percentage rank of their sensitivity. Solid symbols
are benthic genera; open symbols are water column genera. Arrows indicate greater than values.
5-5
-------
Derivation of Dieldrin ESBWQCs
benthic organisms relative to specific concentrations of
dieldrin in sediments in the field. It is, however,
intended to guide scientists and managers through the
complexity of available data relative to potential risks to
benthic taxa posed by sediments contaminated with
dieldrin.

Figures 5-1 and 5-2 are recreations of Figures 3-1
and 3-2, respectively, with GMAVs taken from Appendix
A to calculate PGMCVs using Equation 5-7. The
freshwater ESBWQC for dieldrin (12 ,wg/goc) is less than
any of the PGMCVs or LC50 values from spiked
sediment toxicity tests (Figure 5-1). The PGMCVs for 18
of 21 freshwater genera are greater than the upper 95%
confidence interval of the ESBWQC (27 ,wg/goc). The
PGMCVs for the stoneflies Pteronarcella (22 ,wg/goc),
Pteronarcys (22 ^g/goc), and Claassenia (26 ^g/goc)
are below the ESBWQC upper 95% confidence interval.
This illustrates why the slope of the species sensitivity
distribution is important. It also suggests that, if the
extrapolation from water-only acute lethality tests to
chronically acceptable sediment concentrations is
accurate, these or similarly sensitive genera may be
chronically affected by sediment concentrations
marginally above the ESBWQC and possibly less than the
95% upper confidence interval. For dieldrin, PGMCVs
range over three orders of magnitude from the most
sensitive to the most tolerant genus (Figure 5-1). A
sediment concentration 20 times the ESBWQC would
include the PGMCVs of 4 of the 13 benthic genera tested
including stoneflies, isopods, and fish.

Tolerant benthic genera such as the amphipod
Gammarus and the crayfish Orconectes may not be
chronically affected in sediments with dieldrin
concentrations up to 1,000 times the ESBWQC (Figure 5-
1; Appendix A). Data from lethality tests with
freshwater organisms exposed to dieldrin-spiked
sediments substantiates this projection; the 10-day
LC50 values from three tests with the amphipod H.
azteca ranged from 110 to 360 times the ESBWQC of
12 ,wg/goc, the 10-day LC50s from two tests with the
midge C. tentans ranged from 2.9 to 7.9 times the
ESBWQC (see insert Figure 5-1; corresponding values
from Table 4-1).

The saltwater ESBWQC for dieldrin (28 ,wg/goc) is
less than all of the PGMCVs for saltwater genera (Figure
5-2). The PGMCVs for the penaeid shrimp Penaeus
duorarum (31 ,wg/goc) and the fishAnguilla rostrata (39
,wg/goc) are lower than the upper 95% confidence
interval for the ESBWQC (62 ^g/goc). For dieldrin,
PGMCVs from the most sensitive to the most tolerant
saltwater genus range over two orders of magnitude. A
sediment concentration 17 times the ESBWQC would
include the PGMCVs of 7 of the 13 benthic genera
tested including 4 arthropod and 3 fish genera. Other
genera of benthic arthropods, polychaetes, and fishes
are less sensitive and might not be expected to be
chronically affected in sediments with dieldrin
concentrations 30 times the ESBWQC.

5.4 Comparison of Dieldrin ESBWQCs to
STORET, National Status and
Trends, and Corps of Engineers, San
Francisco Bay Databases for
Sediment Dieldrin

Dieldrin is frequently measured when samples are
taken to measure sediment contamination, and dieldrin
values are frequently reported in databases of sediment
contamination. This means that it is possible that many
of the sediments from the nation's waterways might
exceed the dieldrin benchmarks. In order to investigate
this possibility, the dieldrin benchmarks were compared
with data from several available databases of sediment
chemistry.

The following description of dieldrin distributions
in Figure 5-3 is somewhat misleading because it
includes data from samples in which the dieldrin
concentration was below the detection limit. These
data are indicated on the plot as "less than" symbols
(<), but are plotted at the reported detection limits.
Because these values represent artificial upper bounds,
not measured values, the percentage of samples in
which the ESB WQC values were actually exceeded may
be less than the percentage reported. Very few of the
measured values from either of the databases exceeded
theESBWQCs.

ASTORET (U.S. EPA, 1989b) data retrieval was
performed to obtain a preliminary assessment of the
concentrations of dieldrin in the sediments of the
nation's water bodies. Log probability plots of dieldrin
concentrations on a dry weight basis in sediments are
shown in Figure 5-3. Dieldrin was found at varying
concentrations in sediments from rivers, lakes, and
near-coastal water bodies in the United States. This
was because of its widespread use and quantity applied
during the 1960s and early 1970s. It was restricted from
registration and production in the United States in
1974. Median concentrations were generally at or near
detection limits in most water bodies for data after 1986.
There was significant variability with dieldrin
concentrations in sediments ranging over nine orders
of magnitude within the country.
5-6
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin

S
SU
s
su
=
•e
.S
Q*

SU
s
SU
=

^_^
-^
3
SU
s
'"B
su
=
2
S

in2

101

iir1

102
103
104
105
106
7
m2

101

10
102
103
104
105
106
m7
in2

101
0
101
102
103
104
105
106
m7
0

r A: Stream
-
r
f
~
r
r
r mmC
-------
Derivation of Dieldrin ESBWQCs
The ESBWQCs for dieldrin can be compared to
existing concentrations of dieldrin in sediments of
natural water systems in the United States as contained
in the STORET database (U.S. EPA, 1989b). These data
are generally reported on a dry weight basis rather than
anorganic carbon-normalized basis. Therefore,
ESBWQC concentrations corresponding to sediment
organic carbon levels of 1% to 10% were compared with
dieldrin's distribution in sediments as examples only.
For freshwater sediments, ESBWQC concentrations were
0.12 /j.g/g dry weight in sediments having 1% organic
carbon and 1.2 /ug/g dry weight in sediments having
10% organic carbon; for marine sediments, ESBWQCs
were 0.28 /j.g/g dry weight and 2.8 /ug/g dry weight,
respectively. Figure 5-3 presents comparisons of these
ESBWQCs with probability distributions of observed
sediment dieldrin levels for streams and lakes
(freshwater systems, shown on A and B) and estuaries
(marine systems, C).
For both streams (n=3,075) and lakes (n=457), the
ESBWQCs of 0.12 /ug/g dry weight for 1% organic
carbon freshwater sediments and of 1.2 /j.g/g dry
weight for 10% organic carbon freshwater sediments
were exceeded in less than 1% of the samples. In
estuaries, the data (n=160) indicate that neither
benchmark, 0.28 /j.g/g dry weight for sediments having
1% organic carbon nor 2.8 /ug/g dry weight for
sediments having 10% organic carbon, was exceeded
by the post 1986 samples. Concentrations of dieldrin in
sediments from estuaries were two orders of magnitude
below the ESBWQC value for 1% organic carbon
sediments and three orders of magnitude below the
ESBWQC value for sediments with TOCs of 10%.

A second database developed as part of the
National Status and Trends Program (NOAA, 1991) was
available for assessing contaminant levels in marine
sediments that were representative of areas away from
sources of contamination. The probability distribution
for these data, on an organic carbon basis, was
compared with the saltwater ESBWQC for dieldrin (28
/j.g/goc) in Figure 5-4. Data presented were from
sediments with 0.20% to 31.9% organic carbon.
The median organic carbon-normalized dieldrin
concentration (0.080 ^g/goc) was two orders of
100
10
00
a o.i
0.01
0.001
ESB
WQCOC
o .
= O O
OCCP
iGOOO
o foc >0.2%
0.0001 '—
0.1
1
10 20 50 80 90

Probability
99
99.9
Figure 5-4. Probability distribution of concentrations of dieldrin in sediments from coastal and estuarine sites
from 1984 to 1989 as measured by the National Status and Trends Program (NOAA, 1991). The
horizontal dashed line is the saltwater ESBWQC value of 28 Hg/goc.
5-8
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
magnitude below the ESBWQC of 28 ^g/goc. None of
these samples (n=408) exceeded the benchmarks.
Hence, these results are consistent with the preceding
comparison between the marine ESBWQCand STORET
data.

A third set of data has been analyzed, from the U.S.
Army Corps of Engineers (1991) monitoring program for
a number of locations in various parts of San Francisco
Bay. For a listing of locations sampled, the number of
observations at each site, and the period during which
the results were obtained, see U.S. EPA (2003a). These
data were collected to examine the quality of dredged
sediments in order to determine their suitability for
open water disposal. The database did not indicate
what determinations were made concerning their
acceptability for this purpose.

Investigators compared the frequency of
occurrence of a given sediment dieldrin concentration
(in individual samples, not dredge sites) with the
ESBWQCs developed using the EqP methodology. A
majorportion (93%) of the samples analyzed had/oc
>0.2%, for which the ESBWQC concentrations are
applicable. The concentrations of dieldrin in sediments
were normalized by the organic carbon content, and the
results are displayed as a probability plot in Figure 5-5
to illustrate the frequency at which different levels are
observed. Nearly all of the samples were less than the
varying detection limits of the analytical tests. Each of
the samples for which actual measurements were
obtained were at least an order of magnitude lower than
the ESBWQC. An estimate of the possible frequency
distribution of sediment concentrations of dieldrin was
developed by the application of an analysis technique
that accounts for the varying detection limits and the
presence of nondetected observations (El-Shaarawi and
Dolan, 1989). The results are illustrated by the straight
line, which suggests that no appreciable number of
exceedences is expected. However, the virtual absence
of detected concentrations makes the distribution
estimates unreliable. They are presented only to
suggest the probable relationship between the levels of
the pesticide in relation to the sediment benchmarks.

Regional-specific differences in dieldrin
concentrations may affect the above conclusions
concerning expected example benchmarks exceedences.
This analysis also does not consider other factors such
as the type of samples collected (i.e., whether samples
were from surficial grab samples or vertical core
profiles) or the relative frequencies and intensities of
sampling in different study areas. It is presented as an
aid in assessing the range of reported dieldrin sediment
10'
"Sb

!
I 10"
10s

10'
0.1
10 20 50 80 90

Probability
99
99.9
Figure 5-5. Probability distribution of organic carbon-normalized sediment dieldrin concentrations from the U.S.
Army Corps of Engineers (1991) monitoring program of San Francisco Bay. Sediment dieldrin
concentrations less than the detection limits are shown as open triangles (V); measured concentrations
are shown as solid circles (•). The solid line is an estimate of the distribution developed by accounting
for nondetected observations.
5-9
-------
Derivation of Dieldrin ESBWQCs
concentrations and the extent to which they may
exceed the ESBWQC.
5.5 Limitations to the Applicability of
ESBs

Rarely, if ever, are contaminants found alone in
naturally occurring sediments. Obviously, the fact that
the concentration of a particular contaminant does not
exceed the ESBs does not mean that other chemicals,
for which there are no ESBs available, are not present in
concentrations sufficient to cause harmful effects.
Furthermore, even if ESBs were available for all of the
contaminants in a particular sediment, there might be
additive or synergistic effects that the benchmarks do
not address. In this sense, the ESBs represents a "best
case" benchmark.

It is theoretically possible that antagonistic
reactions between chemicals could reduce the toxicity
of a given chemical such that it might not cause
unacceptable effects on benthic organisms at
concentrations above the ESBs when it occurs with the
antagonistic chemical. However, antagonism has rarely
been demonstrated. More common would be instances
where toxic effects occur at concentrations below the
ESBs because of the additive toxicity of many common
contaminants such as heavy metals and polycyclic
aromatic hydrocarbons (PAHs) (Alabaster and Lloyd,
1982), and instances where other toxic compounds for
which no ESBs exist occur along withESB chemicals.

Care must be used in applying EqP-derived
benchmarks in disequilibrium conditions. In some
instances, site-specific ESBs may be required to
address disequilibrium. The ESBs assume that
nonionic organic chemicals are in equilibrium with the
sediment and interstitial water and are associated with
sediment primarily through adsorption to sediment
organic carbon. In order for these assumptions to be
valid, the chemical must be dissolved in interstitial
water and partitioned into sediment organic carbon.
Therefore, the chemical must be associated with the
sediment for a sufficient length of time for equilibrium
to be reached. In sediments where particles of
undissolved dieldrin occur, disequilibrium exists and
the benchmarks are overprotective. In liquid chemical
spill situations, disequilibrium concentrations in
interstitial and overlying water may be proportionately
higher relative to sediment concentrations. In this case
the benchmarks may be underprotective.
Note that the Koc values used in the EqP
calculations described in this document assume that
the organic carbon in sediments is similar in
partitioning properties to "natural" organic carbon
found in most sediments. While this has proven true
for most sediments EPA has studied, it is possible that
some sites may have components of sediment organic
carbon with different properties. This might be
associated with sediments whose composition has
been highly modified by industrial activity, resulting in
high percentages of atypical organic carbon such as
rubber, animal processing waste (e.g., hair or hide
fragments), coal particles, or wood processing wastes
(bark, wood fiber, or chips). Relatively undegraded
woody debris or plant matter (e.g., roots, leaves) may
also contribute organic carbon that partitions
differently from typical organic carbon (e.g., Iglesias-
Jimenezetal., 1997;Grathwohl, 1990; Xing etal., 1994).
Sediments with substantial amounts of these materials
may exhibit higher concentrations of chemicals in
interstitial water than would be predicted using generic
Koc values, thereby making the ESBs underprotective.
If such a situation is encountered, the applicability of
literature KQC values can be evaluated by analyzing for
the chemical of interest in both sediment and interstitial
water. If the measured concentration in interstitial
water is markedly greater (e.g., more than twofold) than
that predicted using the Koc values recommended
herein (after accounting for DOC binding in the
interstitial water), then the ESBs would be under-
protective and calculation of a site-specific ESB should
be considered (see U.S. EPA, 2003b).

The presence of organic carbon in large particles
may also influence the apparent partitioning. Large
particles may artificially inflate the effect of the organic
carbon because of their large mass, but comparatively
small surface area; they may also increase variability in
TOC measurements by causing sample heterogeneity.
The effect of these particles on partitioning can be
evaluated by analysis of interstitial water as described
above, and site-specific ESBs may be used if required.
It may be possible to screen large particles from
sediment prior to analysis to reduce their influence on
the interpretation of sediment chemistry relative to
ESBs.

In very dynamic areas, with highly erosional or
depositional bedded sediments, equilibrium may not be
attained with contaminants. However, even highKQW
nonionic organic compounds come to equilibrium in
clean sediment in a period of days, weeks, or months.
Equilibrium times are shorter for mixtures of two
sediments that each have previously been at
equilibrium. This is particularly relevant in tidal
5-10
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
situations where large volumes of sediments are eroded
and deposited, even though near equilibrium
conditions may predominate over large areas. Except
for spills and paniculate chemical, near equilibrium is
the rule and disequilibrium is less common. In
instances where it is suspected that EqP does not
apply for a particular sediment because of
disequilibrium discussed above, site-specific
methodologies may be applied (U.S. EPA, 2003b).
5-11
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
Section 6
Sediment Benchmark Values:
Application and Interpretation
6.1 Benchmarks
Based on the level of protection provided by WQC,
the procedures described in this document indicate that
benthic organisms should be comparably protected from
adverse effects of dieldrin where dieldrin
concentrations in sediment are below the ESBWQC
values of 12 (j^g dieldrin/goc for freshwater sediments
and 28 |j,g dieldrin/goc for marine/estuarine sediments,
except possibly where a locally important species is
very sensitive or sediment organic carbon is < 0.2%.

Confidence limits of 5.4 to 27 jj,g/goc for
freshwater sediments and 12 to 62 jj,g/goc for marine/
estuarine sediments are provided as an estimate of the
uncertainty associated with the degree to which
toxicity can be predicted using the Koc and the water-
only effects concentration. Confidence limits do not
incorporate uncertainty associated with water quality
criteria, or unusual, site-specific circumstances. An
understanding of the theoretical basis of the
equilibrium partitioning methodology, uncertainty, and
the partitioning and toxicity of dieldrin are required in
the use of ESBs and their confidence limits.

The benchmarks presented in this document are
the concentrations of a substance that may be present
in sediment while still protecting benthic organisms
from the effects of that substance. These benchmarks
are applicable to a variety of freshwater and marine
sediments because they are based on the biologically
available concentration of the substance in those
sediments.

These benchmarks do not protect against additive,
synergistic, or antagonistic effects of contaminants or
bioaccumulative effects to aquatic life, wildlife or
human health. Consistent with the recommendations of
EPA's Science Advisory Board, publication of these
documents does not imply the use of ESBs as stand-
alone, pass-fail criteria for all applications; rather,
exceedances of ESBs could trigger collection of
additional assessment data.

6.2 Considerations in the Application and
Interpretation of ESBs (also see
Section 5.5)

6.2.1 Relationship of ESBWQC to Expected
Effects

The ESBWQC should be interpreted as a chemical
concentration below which adverse effects are not
expected. In comparison, at concentrations above the
ESB c effects may occur. In principle, above the
upper confidence limit effects are expected if the
chemical is bioavailable as predicted by EqP theory. In
general terms, the degree of effect expected increases
with increasing dieldrin concentration in the sediment.
Because the FCV is derived as an estimate of the
concentration causing chronic toxicity to sensitive
organisms, effects of this type may be expected when
sediment concentrations are near the ESBWQC. As
sediment concentrations increase beyond the ESBWQC,
one can expect chronic effects on less sensitive species
and/or acute effects on sensitive species.
6.2.2 Use of EqP to Develop Alternative
Benchmarks

The FCV is used to define a threshold for
unacceptable effects based on its precedence in
establishing unacceptable effects in the development of
WQC. However, the use of EqP to assess sediment
contamination is not limited to the ESB c and the
associated level of protection. By substituting water-
only effect values other than the FCV into the ESB
equation, other benchmarks may be developed that are
useful in evaluating specific types of biological effects,
or that better represent the ecological protection goals
for specific assessments.
6-1
-------
Sediment Benchmark Values: Application and Interpretation
6.2.3 Influence of Unusual Forms of
Sediment Organic Carbon

Partition coefficients used for calculating these
ESBs are based on estimated and measured partitioning
from natural organic carbon in typical field sediments.
Some sediments influenced heavily by anthropogenic
activity may contain sources of organic carbon whose
partitioning properties are not similar, such as rubber,
animal processing wastes (e.g., hair or hide fragments),
or wood processing wastes (bark, wood fiber or chips).
Relatively undegraded woody debris or plant matter
(e.g., roots, leaves) may also contribute organic carbon
that results in partitioning different from that of typical
organic carbon. Sediments with large amounts of these
materials may show higher concentrations of chemicals
in interstitial water than would be predicted using
generic Koc values, making the ESBs underprotective.
Direct analysis of interstitial water can be used to
evaluate this possibility (see U.S. EPA, 2003a,b); if
necessary, derivation of site-specific Koc values may
be warranted.
6.2.4 Relationship to Risks Mediated
through Bioaccumulation and
Trophic Transfer

As indicated above, ESBs are designed to address
direct toxicity to benthic organisms exposed directly to
contaminated sediment. They are not designed to
address risks that may occur through bioaccumulation
and subsequent exposure of pelagic aquatic organisms
(e.g., predatory fish), terrestrial or avian wildlife, or
humans. No inference can be drawn between
attainment of the ESBWQC and the potential for risk via
bioaccumulation; the potential for those risks must be
addressed by separate means.
6.2.5 Exposures to Chemical Mixtures

The methodology described in this document can be
used to derive ESBWQCs that protect against the specific
toxic effects of dieldrin; it does not account for
potential antagonistic, additive, or synergistic effects
that may occur in sediments containing a mixture of
dieldrin and other chemicals. Consideration of this
potential must be on a site-specific basis. In general
terms, it might be expected that chemicals with
toxicological modes of action similar to dieldrin may
show additive toxicity with dieldrin
6.2.6 Interpreting ESBs in Combination
with Toxicity Tests

Sediment toxicity tests provide an important
complement to ESBs in interpreting overall risk from
contaminated sediments. Toxicity tests have different
strengths and weaknesses compared to chemical-
specific guidelines, and the most powerful inferences
can be drawn when both are used together.
Unlike chemical-specific guidelines, toxicity tests
are capable of detecting any toxic chemical, if it is
present in toxic amounts; one does not need to know
what the chemicals of concern are to monitor the
sediment. Toxicity tests are also useful for detecting
the combined effect of chemical mixtures, if those
effects are not considered in the formulation of the
applicable chemical-specific guideline.

On the other hand, toxicity tests have weaknesses
also; they provide information only for the species
tested, and also only for the endpoints measured. This
is particularly critical given that most sediment
toxicity tests conducted at the time of this writing
primarily measure short-term lethality; chronic test
procedures have been developed and published for some
species, but these procedures are more resource-
intensive and have not yet seen widespread use. In
contrast, the ESBWQC is intended to protect most
species against both acute and chronic effects.

Many assessments may involve comparison of
sediment chemistry (relative to ESBs or other sediment
quality guidelines) and toxicity test results. In cases
where results using these two methods agree (either
both positive or both negative), the interpretation is
clear. In cases where the two disagree, the
interpretation is more complex and required further
evaluation.

Individual ESBs address only the effects of the
chemical or group of chemicals for which they are
derived. For this reason, if a sediment shows toxicity
but does not exceed the ESB for a chemical of
interest, it is likely that the cause of toxicity is a
different chemical or chemicals. This result might
6-2
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
also occur if the partitioning of the chemical in a
sediment is different from that assumed by the ^Toc
value used (see "6.2.3 Influence of Unusual Forms of
Sediment Organic Carbon" above).

In other instances, it may be that an ESBWQC is
exceeded but the sediment is not toxic. As explained
above, these findings are not mutually exclusive,
because the inherent sensitivity of the two measures is
different. The ESB c is intended to protect relatively
sensitive species against both acute and chronic effects,
whereas toxicity tests are run with specific species that
may or may not be sensitive to chemicals of concern,
and often do not encompass the most sensitive endpoints
(e.g., growth or reproduction). As such, one would not
expect an dieldrin concentration near the ESBWQC to
cause lethality in a short-term test. It is also possible
for a sediment above the ESBWQC to be non-toxic if
there are site-specific conditions that run counter to the
equilibrium partitioning model and its assumptions as
outlined in this document.

A good method for evaluating the results of toxicity
tests is to calculate effect concentrations in sediment
that are species and endpoint specific. For species
contained in the water-only toxicity data for the
dieldrin ESB s (Section 3), effect concentrations in
sediment can be calculated that are specific for that
organism using procedures in Section 5. These values
could then be used to directly judge whether the
absence of toxicity in the toxicity test would be
expected from the concentration of dieldrin present.

If the exceedance of an ESB is sufficient that one
would expect effects in a toxicity test but they are not
observed, it is prudent to evaluate the partitioning
behavior of the chemical in the sediment. This is
performed by isolating interstitial water from the
sediment and analyzing it for dieldrin. Predicted
concentrations of dieldrin in the interstitial water can
be calculated from the measured concentrations in the
solid phase (normalized to organic carbon) as follows
u.g chemical/L = (u.g chemical/goc) x 103goc/Kgoc ^
^oc
For chemicals with log ^QW great£r than 5.5,
corrections for DOC binding in the interstitial water
will be necessary (see Gschwend and Wu 1985;
Burkhard 2000). If the measured chemical in the
interstitial water is substantially less (e.g., 2-3 fold
lower or more), it suggests that the organic carbon in
that sediment may not partition similarly to more
typical organic carbon, and derivation of site-specific
ESBs based on interstitial water may be warranted
(U.S.EPA2003b).
6.3 Summary

Based on the level of protection provided by WQC,
the procedures described in this document indicate that
benthic organisms should be comparably protected from
adverse effects of dieldrin where dieldrin
concentrations in sediment are below the ESB
values of 12 \ig dieldrin/goc for freshwater sediments
and 28 \ig dieldrin/goc for marine/estuarine sediments,
except possibly where a locally important species is
very sensitive or sediment organic carbon is < 0.2%.
The ESBs do not consider the antagonistic, additive
or synergistic effects of other sediment contaminants in
combination with dieldrin or the potential for
bioaccumulation and trophic transfer of dieldrin to
aquatic life, wildlife or humans. Consistent with the
recommendations of EPA's Science Advisory Board,
publication of these documents does not imply the use
of ESBs as stand-alone, pass-fail criteria for all
applications; rather, exceedances of ESBs could trigger
collection of additional assessment data.
6-3
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
Section 7
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of five organochlorine compounds in water and
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National Academy of Sciences (NAS). 1973. Water
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National Oceanic and Atmospheric Administration
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Nebeker AV, Schuytema GS, Griffis WL, Barbitta JA,
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Parrish PR, Couch JA, Forester J, Patrick JM Jr, Cook
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Corvallis, OR.

Sanders HO. 1969. Toxicity of pesticides to the
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Sanders HO. 1972. Toxicity of some insecticides to four
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Sanders HO, Cope OB. 1966. Toxicities of several
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Schoettger RA. 1970. Fish-Pesticide Research
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SharomMS, Miles JR, Harris CR, McEwenFL. 1980.
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14:1089-1093.
7-3
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7-5
-------
A
of for
used to the
for
-------
Appendix A
Common Name, Life-
Scientific Name stagea
Freshwater Species
Annelid, A
Lumbriculus
variegatus
Cladoceran, J
Daphniapulex
Cladoceran, X
Daphniapulex
Cladoceran, J
Daphnia magna
Cladoceran, A
Daphnia magna
Cladoceran, J
Daphnia magna
Cladoceran, J
Simocephalus
serrulatus

Cladoceran, X
Simocephalus
serrulatus

Isopod, X
Asellus
brevicaudus

Scud, A
Gammarus
fasciatus

Scud, X
Gammarus
fasciatus

LC50/EC506 (ng/L)
HMAV ,,
overall
Habitat*5 Method0 Concentrationd Test Speciesf GenusS GMAVh Reference

I FT M 21.8 21.8 21.8 21.8 Brooke,
1993b

W S U 250 — — — Mayer and
Ellersieck,
1986
W S U 250 250 — — Sanders and
Cope, 1966
W S U >200 — — — Adema, 1978

W S U >200 — — — Adema, 1978

W R M 79.5 >147.1 >191.8 >191.8 Brooke,
1993a
E,W S U 240 — — — Sanders and
Copei 1966;
Mayer and
Ellersieck,
1986
E,W S U 190 213.5 213.5 213.5 Sanders and
Cope, 1966;
Mayer and
Ellersieck,
1986
E S U 5.0 5.0 5.0 5.0 Sanders,
1972;
Mayer and
Ellersieck,
1986
E S U 640 — — — Sanders,
1972;
Mayer and
Ellersieck,
1986
E S U 600 619.7 — — Sanders,
1972;
Mayer and
Ellersieck,
1986
A-2
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
Common Name, Life-
Scientific Name stagea
Scud, X
Gammarus
lacmtris
Glass shrimp, X
Palaemonetes
kadiakensis
Crayfish, A
Orconectes
nais

Damselfly, J
Ischnura
verticalis
Stonefly, J
Claassenia
sabulosa
Stonefly, J
Petronarcys
californica
Stonefly, J
Pteronarcella
badia
Rainbow trout, J
Oncorhynchus
mykiss
Rainbow trout, J
Oncorhynchus
mykiss
Rainbow trout, J
Oncorhynchus
mykiss
Rainbow trout, J
Oncorhynchus
mykiss
Rainbow trout, J
Oncorhynchus
mykiss
Rainbow trout, X
Oncorhynchus
mykiss
LC50/EC506 (ng/L)
HMAV ,,
overall
Habitat*5 Method0 Concentrationd Test Speciesf GenusS GMAVh Reference
E S U 567.5 567.5 593.0 593.0 Sanders,
1969

E S U 20 20 20 20 Sanders,
1972

E S U 740 740 740 740 Sanders,
1972;
Mayer and
Ellersieck,
1986
E S U 12 12 12 12 Mayer and
Ellersieck,
1986
E,W S U 0.58 0.58 0.58 0.58 Mayer and
Ellersieck,
1986
I,E S U 0.5 0.5 0.5 0.5 Mayer and
Ellersieck,
1986
I,E S U 0.5 0.5 0.5 0.5 Mayer and
Ellersieck,
1986
W S U 9.9 — — — Katz, 1961

W S U 9.59 — — — Douglas et
al, 1986
W S U 2.4 — — — Maceket
al., 1969
W S U 1.1 — — — Maceket
al., 1969
W S U 1.4 — — — Maceket
al., 1969
W S U 1.2 — — — Mayer and
Ellersieck,
1986
A-3
-------
Appendix A
Common Name, Life-
Scientific Name stagea
Rainbow trout, X
Oncorhynchus
mykiss
Rainbow trout, X
Oncorhynchus
mykiss
Rainbow trout, X
Oncorhynchus
mykiss
Rainbow trout, X
Oncorhynchus
mykiss
Rainbow trout, X
Oncorhynchus
mykiss
Rainbow trout, J
Oncorhynchus
mykiss
Coho salmon, J
Oncorhynchus
kisutch
Chinook X
salmon,
Oncorhynchus
tshawytscha
Chinook J
salmon,
Oncorhynchus
tshawytscha
Cutthroat trout, X
Oncorhynchus
clarki
Goldfish, J
Carassius
auratus
Goldfish, J
Carassius
auratus
Goldfish, J
Carassius
auratus
LC50/EC506 (ng/L)
HMAV ,,
overall
Habitat*5 Method0 Concentrationd Test Speciesf GenusS GMAVh Reference
W S U 1.2 — — — Mayer and
Ellersieck,
1986
W S U 1.2 — — — Mayer and
Ellersieck,
1986
W S U 1.4 — — — Mayer and
Ellersieck,
1986
W S U 1.5 — — — Mayer and
Ellersieck,
1986
W S U 2.3 — — — Mayer and
Ellersieck,
1986
W FT M 8.23 8.23 — — Brooke,
1993a

W S U 10.8 10.8 — — Kate, 1961

W FT U 1.54 — — — Schoettger,
1970

W S U 6.1 3.065 — — Kate, 1961

W S U 6.0 6.0 6.358 6.358 Mayer and
Ellersieck,
1986
W S U 41 — — — Henderson
etal, 1959

W S U 1.6 — — — Mayer and
Ellersieck,
1986
W S U 1.8 4.906 4.906 4.906 Mayer and
Ellersieck,
1986
A-4
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
Common Name, Life-
Scientific Name stagea
Fathead J
minnow,
Pimephales
promelas
Fathead J
minnow,
Pimephales
promelas
Fathead J
minnow,
Pimephales
promelas
Fathead J
minnow,
Pimephales
promelas
Fathead J
minnow,
Pimephales
promelas
Fathead J
minnow,
Pimephales
promelas
Fathead J
minnow,
Pimephales
promelas
Fathead J
minnow,
Pimephales
promelas
Fathead L
minnow,
Pimephales
promelas
Fathead J
minnow,
Pimephales
promelas
Guppy, J
Poecilia
reticulata

LC50/EC506 (ng/L)
HMAV ,,
overall
Habitat*5 Method0 Concentrationd Test Speciesf GenusS GMAVh Reference
W S U 18 — — — Henderson et
al., 1959

W S U 18 — — — Henderson et
al., 1959

W S U 36 — — — Tarzwelland
Henderson,
1957
W S U 24 — — — Tarzwelland
Henderson,
1957
W S U 16 — — — Tarzwelland
Henderson,
1957
W S U 25 — — — Tarzwelland
Henderson,
1957
W S U 23 — — — Tarzwelland
Henderson,
1957
W S U 3.8 — — — Mayer and
Ellersieck,
1986
W FT M 6.59 — — — McCauley,
1997

W FT M 4.45 5.415 5.415 5.415 McCauley,
1997

W S U 3.616 — — — Chadwick
and
Kiigemagi,
1968
A-5
-------
Appendix A
Common Name, Life-
Scientific Name stagea
Guppy, J
Poecilia
reticulata
Guppy, J
Poecilia
reticulata
Guppy, J
Poecilia
reticulata

Guppy, J
Poecilia
reticulata
Guppy, J
Poecilia
reticulata

Guppy, J
Poecilia
reticulata

Guppy, J
Poecilia
reticulata
Guppy, J
Poecilia
reticulata

Guppy, J
Poecilia
reticulata

LC50/EC506 (ng/L)
HMAV ,,
overall
Habitat*5 Method0 Concentrationd Test Speciesf GenusS GMAVh Reference
W S U 3.219 — — — Chadwick
and
Kiigemagi,
1968
W S U 2.912 — — — Chadwick
and
Kiigemagi,
1968
W S U 3.306 — — — Chadwick
and
Kiigemagi,
1968
W S U 2.328 — — — Chadwick
and
Kiigemagi,
1968
W S U 2.496 — — — Chadwick
and
Kiigemagi,
1968
W S U 2.047 — — — Chadwick
and
Kiigemagi,
1968
W S U 2.430 — — — Chadwick
and
Kiigemagi,
1968
W S U 2.047 — — — Chadwick
and
Kiigemagi,
1968
W S U 3.672 — — — Chadwick
and
Kiigemagi,
1968
W S U 3.645 — — — Chadwick
and
Kiigemagi,
1968
W S U 6.048 — — — Chadwick
and
Kiigemagi,
1968
A-6
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
Common Name, Life-
Scientific Name stagea
Guppy, J
Poecilia
reticulata
Guppy, J
Poecilia
reticulata
Guppy, J
Poecilia
reticulata
Guppy, J
Poecilia
reticulata
Guppy, J
Poecilia
reticulata
Guppy, J
Poecilia
reticulata
Guppy, J
Poecilia
reticulata
Guppy, J
Poecilia
reticulata
Guppy, J
Poecilia
reticulata
Guppy, J
Poecilia
reticulata
Guppy, J
Poecilia
reticulata
LC50/EC506 (ug/L)
HMAV ,,
overall
Habitat*5 Method0 Concentrationd Test Speciesf GenusS GMAVh Reference
W S U 7.869 — — — Chadwick
and
Kiigemagi,
1968
W S U 4.000 — — — Chadwick
and
Kiigemagi,
1968
W S U 3.666 — — — Chadwick
and
Kiigemagi,
1968
W S U 3.290 — — — Chadwick
and
Kiigemagi,
1968
W S U 2.262 — — — Chadwick
and
Kiigemagi,
1968
W S U 2.754 — — — Chadwick
and
Kiigemagi,
1968
W S U 7.458 — — — Chadwick
and
Kiigemagi,
1968
W S U 6.552 — — — Chadwick
and
Kiigemagi,
1968
W S U 6.893 — — — Chadwick
and
Kiigemagi,
1968
W S U 6.975 — — — Chadwick
and
Kiigemagi,
1968
W S U 9.100 — — — Chadwick
and
Kiigemagi,
1968
A-7
-------
Appendix A
Common Name, Life-
Scientific Name stagea
Guppy, J
Poecilia
reticulata
Guppy, J
Poecilia
reticulata
Guppy, J
Poecilia
reticulata

Guppy, J
Poecilia
reticulata
Guppy, J
Poecilia
reticulata

Guppy, J
Poecilia
reticulata

Guppy, J
Poecilia
reticulata
Guppy, J
Poecilia
reticulata

Guppy, J
Poecilia
reticulata

LC50/EC506 (ng/L)
HMAV ,,
overall
Habitat*5 Method0 Concentrationd Test Speciesf GenusS GMAVh Reference
W S U 5.940 — — — Chadwick
and
Kiigemagi,
1968
W S U 4.818 — — — Chadwick
and
Kiigemagi,
1968
W S U 5.865 — — — Chadwick
and
Kiigemagi,
1968
W S U 3.713 — — — Chadwick
and
Kiigemagi,
1968
W S U 6.375 — — — Chadwick
and
Kiigemagi,
1968
W S U 4.563 — — — Chadwick
and
Kiigemagi,
1968
W S U 4.181 — — — Chadwick
and
Kiigemagi,
1968
W S U 3.488 — — — Chadwick
and
Kiigemagi,
1968
W S U 4.173 — — — Chadwick
and
Kiigemagi,
1968
W S U 4.032 — — — Chadwick
and
Kiigemagi,
1968
W S U 3.569 — — — Chadwick
and
Kiigemagi,
1968
A-8
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
Common Name, Life-
Scientific Name stagea
Guppy, J
Poecilia
reticulata

Guppy, J
Poecilia
reticulata

Guppy, X
Poecilia
reticulata

Guppy, X
Poecilia
reticulata
Guppy, X
Poecilia
reticulata
Guppy, J
Poecilia
reticulata
Guppy, J
Poecilia
reticulata
Green sunfish, J
Lepomis
cyanellus
Green sunfish, J
Lepomis
cyanellus
Green sunfish, J
Lepomis
cyanellus
Bluegill, J
Lepomis
macrochirus
LC50/EC506 (ng/L)
HMAV ,,
overall
Habitat*5 Method0 Concentrationd Test Speciesf GenusS GMAVh Reference
W S U 3.010 — — — Chadwick
and
Kiigemagi,
1968
W S U 3.280 — — — Chadwick
and
Kiigemagi,
1968
W S U 2.660 — — — Chadwick
and
Kiigemagi,
1968
W S U 3.431 — — — Chadwick
and
Kiigemagi,
1968
W S U 25 — — — Henderson et
al, 1959

W S U 21 — — — Cairns and
Loos, 1966

W S U 3.2 — — — Ademaand
Vink, 1981

W S U 7 4.313 4.313 4.313 Ademaand
Vink, 1981

W S U 6 — — — Tarzwelland
Henderson,
1957
W S U 11 — — — Tarzwelland
Henderson,
1957
W S U 8 8.082 — — Tarzwelland
Henderson,
1957
W S U 9 — — — Henderson et
al., 1959
A-9
-------
Appendix A
Common Name, Life-
Scientific Name stagea
Bluegill, J
Lepomis
macrochirus
Bluegill, J
Lepomis
macrochirus
Bluegill, J
Lepomis
macrochirus
Bluegill, J
Lepomis
macrochirus
Bluegill, J
Lepomis
macrochirus
Bluegill, J
Lepomis
macrochirus
Bluegill, J
Lepomis
macrochirus
Bluegill, J
Lepomis
macrochirus
Bluegill, J
Lepomis
macrochirus
Bluegill, J
Lepomis
macrochirus
Bluegill, J
Lepomis
macrochirus
Bluegill, J
Lepomis
macrochirus
Bluegill, J
Lepomis
macrochirus
LC50/EC506 (ng/L)
HMAV ,,
overall
Habitat*5 Method0 Concentrationd Test Speciesf GenusS GMAVh Reference
W S U 17 — — — Maceketal,
1969
W S U 14 — — — Maceketal.,
1969
W S U 8.8 — — — Maceketal.,
1969
W S U 32 — — — Tarzwelland
Henderson,
1957
W S U 18 — — — Tarzwelland
Henderson,
1957
W S U 8 — — — Tarzwelland
Henderson,
1957
W S U 22 — — — Tarzwelland
Henderson,
1957
W S U 3.1 — — — Mayer and
Ellersieck,
1986
W S U 4.7 — — — Mayer and
Ellersieck,
1986
W S U 16.0 — — — Mayer and
Ellersieck,
1986
W S U 18.0 — — — Mayer and
Ellersieck,
1986
W S U 14.5 — — — Mayer and
Ellersieck,
1986
W S U 9.3 — — — Mayer and
Ellersieck,
1986
A-10
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
Common Name, Life-
Scientific Name stagea
Bluegill, J
Lepomis
macrochirus
Bluegill, J
Lepomis
macrochirus
Largemouth X
bass,
Micropterus
dolomieu
Black X
bullhead,
Ictalurus
melas
Channel X
catfish,
Ictalurus
punctatus
Channel X
catfish,
Ictalurus
punctatus
Tilapia, J
Tilapia
mossambica
Tilapia, J
Tilapia
mossambica
Fowler's L
toad,
Bufofowleri
Western L
chorus frog,
Pseudocris
triseriata
Saltwater Species
Polychaete L
worm,
Ophryotroch
a diadema
Polychaete A
worm,
Ophryotroch
a diadema
LC50/EC506 (ng/L)
HMAV ,,
overall
Habitat*5 Method0 Concentrationd Test Speciesf GenusS GMAVh Reference
W S U 7.1 — — — Mayer and
Ellersieck,
1986
W FT U 3.9 10.71 9.304 9.304 Mayer and
Ellersieck,
1986
W S U 3.5 3.5 3.5 3.5 Mayer and
Ellersieck,
1986

E S U 10.0 10.0 — — Mayer and
Ellersieck,
1986

E S U 4.5 — — — Mayer and
Ellersieck,
1986

E S U 7.8 5.924 7.697 7.697 Mayer and
Ellersieck,
1986

W S U 9.2 — — — Mayer and
Ellersieck,
1986
W S U 10.0 9.592 9.592 9.592 Mayer and
Ellersieck,
1986
E S U 150 150 150 150 Mayer and
Ellersieck,
1986
E S U 100 100 100 100 Mayer and
Ellersieck,
1986

I R U >100 — — — Hooftman
and Vink,
1980

I R U >100 >100 >100 >100 Hooftman
and Vink,
1980

A-ll
-------
Appendix A
Common Name, Life-
Scientific Name stagea
Eastern oyster, E,L
Crassostrea
virginica
Mysid, A
Americamysis
bahia
Mysid, A
Americamysis
bahia
Sand shrimp, A
Crangon
septemspinosa
Hermit crab, A
Pagurus
longicarpus
Grass shrimp, A
Palaemonetes
vulgaris
Grass shrimp, A
Palaemonetes
pugio
Korean A
shrimp,
Palaemon
macrodactylus
Korean A
shrimp,
Palaemon
macrodactylus
Pink shrimp, A
Penaeus
duorarum
American eel, J
Anguilla
rostrata
Chinook J
salmon,
Oncorhynchus
tshawytscha
Atlantic J
silverside,
Menidia
menidia
LC50/EC506 (ng/L)
HMAV ,,
overall
Habitat*5 Method0 Concentrationd Test Speciesf GenusS GMAVh Reference
W S U 640 640 640 640 Davis and
Hidu, 1969

E S U 3.7 — — — U.S. EPA,
1987b

E FT M 4.5 4.5 4.5 4.5 U.S. EPA,
1987b

E S U 7 7 7 7 Eisler,
1969

E S U 18 18 18 18 Eisler,
1969

E,W S U 50 50 — — Eisler,
1969

E,W FT M 8.64 8.64 20.78 20.78 Parrish et
al., 1973

E,W S U 16.9 — — — Schoettger,
1970

E,W FT U 6.9 10.80 10.80 10.80 Schoettger,
1970

I,E FT M 0.70 0.70 0.70 0.70 Parrish et
al., 1973

E S U 0.9 0.9 0.9 0.9 Eisler,
1970b

W FT U 1.47 1.47 1.47 1.47 Schoettger,
1970

W S U 5555 Eisler,
1970b

A-12
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Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
Common Name, Life-
Scientific Name stagea
Sheepshead A
minnow,
Cyprinodon
variegatus
Mummichog, A
Fundulus
heteroclitus
Mummichog, A
Fundulus
heteroclitus
Striped J
killifish,
Fundulus
majalis
Threespine J
stickleback,
Gasterosteus
aculeatus
Threespine J
stickleback,
Gasterosteus
aculeatus
Striped bass, J
Morone
saxatilis
Shiner perch, J
Cymatogaster
aggregata
Shiner perch, J
Cymatogaster
aggregata
Dwarf perch, A
Micrometrus
minimus
Dwarf perch, A
Micrometrus
minimus
Bluehead, A
Thalassoma
bifasciatum
LC50/EC506 (ng/L)
HMAV ,,
overall
Habitat*5 Method0 Concentrationd Test Speciesf GenusS GMAVh Reference
E,W FT M 10.00 10.00 10.00 10.00 Parrish et
al, 1973

E,W S U 5 — — — Eisler,
1970a

E,W S U 16 8.944 — — Eisler,
1970b

E,W S u 4 4 5.981 5.981 Eisler,
1970b

E,W S U 15.3 — — — Katz, 1961

E,W S U 13.1 14.16 14.16 14.16 Katz, 1961

E FT U 19.7 19.7 19.7 19.7 Kornand
Earnest,
1974
W S U 3.7 — — — Earnest and
Benville,
1972
W FT U 1.50 2.356 2.356 2.356 Earnest and
Benville,
1972
W S U 5.0 — — — Earnest and
Benville,
1972
W FT U 2.44 3.493 3.493 3.493 Earnest and
Benville,
1972
W S U 6666 Eisler,
1970b

A-13
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Appendix A
LC50/EC50e (ug/L)
Common Name, Life-
HMAV
Overall
Scientific Name stagea Habitat Method0 Concentration Test Species GenusS GMAV Reference
Striped A E S
mullet,
Mugil
cephalus
Northern A W S
puffer,
Sphaeroides
maculatus
U 23 23 23 23 Eisler,
1970b

U 34 34 34 34 Eisler,
1970b

a Life-stage: A = adult, J = juvenile, L = larvae, E = embryo, U = life-stage and habitat unknown, X = life-stage unknown
but habitat known.
Habitat: I = infaunal, E = epibenthic, W = water column.
c Method: S = static, R = renewal, FT = flow-through.
Concentration: U = unmeasured (nominal), M = chemical measured.
e Acute value: 96-hour LC50 or EC50, except for 48-hour EC50 for cladocera, barnacles, and bivalve molluscs (Stephan et al., 1985).
HMAV species: Habitat Mean Acute Value — Species is the geometric mean of acute values by species by habitat (epibenthic,
infaunal, and water column).
§ HMAV genus: Geometric mean of HMAV for species within a genus.
A-14
-------
Appendix B
to JTOC
2-2) to
4-1)
-------
Equilibrium Partitioning Sediment Benchmarks (ESBs): Dieldrin
Sediment Source, Mortality
Species Tested (%)
West Bearskin,
MN
Hyalella azteca

Pequaywan, MN
Hyalella azteca

Airport Pond, MN
Hyalella azteca

Airport Pond, MN
Hyalella azteca
Airport Pond, MN
Chironomus
tentans

Airport Pond, MN
Chironomus
tentans

30
28
38
45
63
13
10
—
40
55
15
60
100
63
30
27
37
53
30
40
47
5
55
50
90
0
5
50
100
100
Sediment
Concentration (,ug/g)
Dry Wt OC
1.43
3.75
12.34
30.69
48.73
14.48
43.81
123.50
249.30
479.37
5.17
25.24
97.38
3.77
16.71
31.55
61.10
136.02
7.29
30.52
115.78
0.09
1.00
5.41
12.98
0.05
0.10
0.52
3.78
9.64
48.15
148.81
474.62
999.67
1450.30
193.58
541.53
1848.80
2280.88
4672.22
304.1
1493.5
5527.3
249.67
960.34
1889.22
3432.58
7556.11
402.76
1623.4
6432.2
4.95
49.26
252.80
658.88
3.45
5.92
36.62
252.00
614.01
Interstitial
Water Cone.
(Mg/L)
14.9
42.3
53.9
210.0
245.5
58.8
146.6
343.8
566.1
518.7
16.70
80.12
89.40
13.5
60.3
136.0
224.4
356.8
30.1
143.3
311.40
—
—
—
—
—
—
—
DOC TOC
Og/L) (%)
— 2.97
— 2.52
— 2.60
— 3.07
— 3.36
— 7.48
— 8.09
— 6.68
— 10.93
— 10.26
— 1.70
— 1.69
— 1.76
69.69 1.51
73.46 1.74
59.89 1.67
63.73 1.78
67.17 1.80
66.0 1.81
75.5 1.88
65.6 1.80
— 1.82
— 2.03
— 2.14
— 1.97
— 1.45
— 1.69
— 1.42
— 1.50
— 1.57
Log^oc

—
—
—
—
—
—
—
—
—
4.82
4.76
4.78
4.75
4.74
4.74
4.73
4.74
—
—
—
—
—
—
—
Reference
Hoke etal.,
1995

Hoke etal.,
1995

Hoke and
Ankley,
1992

Hoke and
Ankley,
1992
Hoke et al.,
1995

Hoke etal.,
1995

103 g/kg
B-2
-------
Appendix C
Quality Assurance Summary for the ESB Document:
Procedures for the derivation of equilibrium
partitioning sediment benchmarks (ESBs)
for the protection of benthic organisms: Dieldrin
-------
All data were obtained either from the WQC document for dieldrin (USEP A, 1980) or from a
comprehensive literature search completed in 1997.
All dataused in the example benchmark calculations were evaluated for acceptability using the
procedures outlined in the Stephan et al. (1985): Guidelines for deriving numerical national
water quality criteria for the protection of aquatic organisms and their uses. Data not
meeting the criteria were rej ected. All calculations were made using the procedures in Stephan
et al. (1985). All calculations were checked by at least one other EPA scientist and then the
document was di stributed for public comment. All data and intermediate values are presented in
tables in the document, and all original data were made available as part of the public comment
process. Any errors of omission or calculation discovered during the public comment process
were corrected and included in the revised document and can be found in Comment Response
Document for the Proposed Equilibrium Partitioning Sediment Guidelines for the
Protection ofBenthic Organisms (U.S. EPA, 2000).
Hard copies of all literature cited in this document reside at ORD/NHEERL Atlantic Ecology
Di vision-Narragan sett, Rhode Island.
C-2
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