&EPA
United States Office of Science and Technology and
Environmental Protection Office of Research and Development
Agency Washington, DC 20460
Methods for the Derivation of
Site-Specific Equilibrium
Partitioning Sediment Guidelines
(ESGs) for the Protection
of Benthic Organisms:
Nonionic Organics
-------
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 meet the objectives of the CWA, EPA has periodically issued ambient water
quality criteria (WQC) beginning with the publication of “Water Quality Criteria, 1972” (NAS,
1973). The development of WQC is authorized by Section 304(a)(1) of the CWA, which directs
the Administrator to develop and publish “criteria” reflecting the latest scientific knowledge on
(1) the kind and extent of effects on human health and welfare, including effects on plankton, fish,
shellfish, and wildlife, that may be expected from the presence of pollutants in any body of water,
including ground water; and (2) the concentration and dispersal of pollutants on biological
community diversity, productivity, and stability. All criteria guidance through late 1986 was
summarized in an EPA document entitled “Quality Criteria for Water, 1986” (U.S. EPA, 1987).
Updates on WQC documents for selected chemicals and new criteria recommendations for other
pollutants have been more recently published as “National Recommended Water Quality Criteria-
Correction” (U.S EPA, 1999). EPA will continue to update the nationally recommended WQC
as needed in the future.
In addition to the development of WQC and to continue to meet the objectives of the CWA, EPA
has conducted efforts to develop and publish equilibrium partitioning sediment guidelines (ESGs)
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 degradatioa 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. These guidelines are
authorized under Section 304(aX2) of the CWA, which directs the Administrator to develop and
publish information on, among other things, the factors necessary to restore and maintain the
chemical, physical, and biological integrity of all navigable waters.
The ESGs and associated methodology presented in this document are EPA’s best recommendation
as to the concentrations of a substance that may be present in sediment while still protecting
benthic organisms from the effects of that substance. These guidelines 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 ESGs 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 ESGs do not protect against synergistic or antagonistic effects of
contaminants or bioaccumulative effects to benthos. They are not protective of wildlife or human
health endpoints.
EPA recommends that ESGs be used 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. EPA is developing guidance to assist in
the application of these guidelines in water-related programs of the States and this Agency.
This document provides guidance to EPA Regions, States, the regulated community, and the
public. It is designed to implement national policy concerning the matters addressed. It does not,
however, 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 decisioiunakers retain the discretion to adopt approaches on a case-by-case basis that
differ from this guidance where appropnate. EPA may change this guidance in the future.
a ii
-------
This document has been reviewed by EPA’s Office of Science and Technology (Health and
Ecological Criteria Division, Washington, DC) and Office of Research and Development (Mid-
Continent Ecology Division, Duluth, MN; Atlantic Ecology Division, Narraganseu, RI; Western
Ecology Division, Corvallis, OR), and approved for publication.
Mention of trade names or commercial products does not constitute endorsement or
recommendation of use.
Front cover image provided by Wayne R. Davis and Virginia Lee.
iv
-------
Contents
Acknowledgments . vi i
Executive Summaiy . i
Glossary of Abbreviations . xi
Section 1
Purpose and Application 1-I
11 General Information 1-1
12 Rationaie for Procedures Used to Develop Site-Specific Guidelines 1-1
13 Definition of Site of Concern and Resident Species at a Site 1-3
Section 2
Procedures for Conducting Site-Specific ESG Modifications 2-1
2..1 Resident Species Deletion/Substitution Procedure 2-1
2.1.1 Rationale for Use of the Resident Species Deletion!
Substitution Procedure 2-1
2.12 Details of the Resident Species Deletion/Substitution Procedure 2-2
2.13 Derivation of the Site-Specific ESG 2-3
22 Bioavailabi lity Procedure 2-4
221 Rationale for Use of the Bioavailabiity Procedure 2-4
2.2.2 Details of the BioavailabilityProcedure 2-5
2.221 Sampling Interstitial Water 2-S
22.2.2 Quantification of Dissolved and DOC-Associated
Phases 2-5
2.2.2.3 Calculating the Freely-Dissolved, Bioavailable Concentration 2-6
2.2.3 Derivation of the Site-Specific ESG 2-7
Section 3
References 3-1
Tables
Table 2-1. Computed organic carbon—normalized partition coefficients 2-7
Table 2-2. Solutions to Equation 2-3 using K values computed from
Equation 2-4 2-7
V
-------
Acknowledgments
Coauthors
David J. Hansen HydroQual, Inc., Mahwah, NJ; Great Lakes Environmental
Center, Traverse City, MI (formerly with U.S. EPA)
Christopher S. Zarba U.S. EPA, Office of Research and Development, Washington, DC
Robert J. Ozretich t U.S. EPA, NIJEERL, Western Ecology Division, Corvallis, OR
Dominic M. Di Toro Maithattan College, Riverdale, NY; HydroQual, Inc.,
Mahwah, NJ
Siguilicant Contributors to the Development of the Approach and Supporting Science
David J. Hansen HydroQual, Inc., Mahwah, NJ; Great Lakes Environmental
Center, Traverse City, MI (formerly with U.S. EPA)
Roberti. Ozretich U.S. EPA, NHEERL, Western Ecology Division, Corvallis, OR
Dominic M. Di Toro Manhattan College, Riverdale, NY; HydroQual, Inc.,
Mahwah, NJ
Technical Support and Document Review
Maria R. Paruta U.S. EPA, N}{EERL, Atlantic Ecology Division,
Narragansett, RI
Heidi E. Bell* U.S. EPA, Office of Water, Washington, DC
Robert L. Spehar U.S. EPA, NIJEERL, Mid-Continent Division, Duluth, MN
Robert M. Burgess U.S. EPA, N}IEERL, Atlantic Ecology Division,
Narragansett, RI
Maiy C. R iley U.S. EPA, Office of Water, Washington, DC
D. Scott Ireland U.S. EPA, Office of Water, Washington, DC
4 Prii ipal U.S. EPA contact
V II
-------
Executive Summary
The purpose of this document is to provide guidance on procedures that can be used to modify
national equilibrium partitioning sediment guidelines (ESGs) for nonionic organic chemicals to
reflect specific local conditions. This methodology is issued in support of the published ESGs for
endrin and dieldrin (U.S. EPA, 2000a,b) and is intended to supplement the procedures described
for calculating ESGs for nonionic organic chemicals based on the equilibrium partitioning (EqP)
theory as described in the ESG Technical Basis Document (U.S. EPA, 200(k).
According to the EqP theory, 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 concentration in the others can be predicted.
The ratio of the concentration in water to the concentration in sediment organic carbon is termed
the organic carbon partition coefficient (K ), which is a constant for each chemical. It has been
demonstrated that if the effect concentration in water is known, for example, a water quality
cnteria final chronic value (WQC FCV), the effect concentration in sediments On an organic
carbon basis (ESGoc) can be accurately predicted by multiplying the effect concentration in water
by the chemical’s Koc(U.S. EPA, 2000c).
The U.S. Environmental Protection Agency (EPA) currently recognizes that the national ESGs
may be under- or overprotective when (1) pertinent differences occur between the sensitivities of
benthic organisms at a site and the organisms used to derive the WQC FCV, or (2) differences
occur in the bioavailability of the chemical in the sediment from the site because of alternate
partitioning phases or the presence in the sediment of undissolved chemical. The two procedures
recommended to correct for such site-specific differences are the Resident Species Deleuon/
Substitutiun Procedure (U.S. EPA, 1994) and the Bioavailabiity Procedure. The basic principle
of the Resident Species Deletion/Substitution Procedure is to permit deletion of all acute values
for nonresident benthic species/life-stages and water column species/life-stages when acute values
for all benthic resident species/life-stages in a family have been tested. The Bioavailabiity
Procedure assumes that the true concentration of bioavailable chemical can be reasonably
measured or estimated as freely-dissolved chemical in interstitial water, which can then be
compared with the WQC FCV. For the latter value, sediments in which the freely-dissolved
interstitial water concentration is less than the WQC FCV are acceptable for maintaining the
presence of benthic organisms. If bioassays demonstrate that a sediment is toxic, EPA
recommends sediment-specific risk assessments. These risk assessments should utilize a tiered
approach prior to conducting the site-specific ESG modification procedures to identify chemicals
causing the observed effects (such as a Toxicity Identification Evaluation LTLE]) (e.g., Anidey et
al., 1991; Ho etal., 1997).
ix
-------
Glossary of Abbreviations
ACR Acute—chronic ratio
ASTM American Society for Testing and Materials
Cd Freely-dissolved interstitial water chemical concentration
Total interstitial water chemical concentration
CWA Clean Water Act
DOC Dissolved organic carbon
EPA United States Environmental Protection Agency
EqP Equilibrium partitioning
ESA Endangered Species Act
ESG(s) Equilibrium partitioning sediment guideline(s)
ESG(X Organic carbon-normalized equilibrium partitioning sediment guideline
ESG( Site-specific organic carbon-normalized equilibrium partitioning sediment
guideline
FACR Final acute-chronic ratio
FACRss Site-specific final acute-water chronic ratio
FAV Final acute value
FAV Site-specific final acute value
FCV Final chronic value
FCV Site-specific final chronic value
GC/MS Gas chromatograpblmass spectrophotometer
GMAV Genus mean acute value
I- 1ECD U.S. EPA, Health and Ecological Criteria Division
Dissolved organic carbon—water partition coefficient
Organic carbon-water partition coefficient
Ocianol—water partition coefficient
L-L Liquid-liquid extraction
NAS National Academy of Sciences
NTIS National Technical Information Service
X l
-------
Section 1
Purpose and Application
1.1 General Information
The purpose of this document is to provide
guidance on procedures that can be used to modify
national equilibrium partitioning sediment guidelines
(ESOs) for nonionic organic chemicals to reflect local
environmental conditions. These procedures may be
utilized as part of the basis for establishing site-
specific sediment quality standards to protect the uses
of a specific water body. The procedures are intended
to apply to the sediment guidelines for endrin and
dieldrin (U.S. EPA, 2000a,b) and ESGs published for
other substances including, but not limited to, mixtures
of metals (cadmium, copper, lead, nickel, silver, and
zinc) (U.S. EPA, 20000 and mixtures of polycyclic
aromatic hydrocarbons (PAHs) (U.S EPA, 2000g).
A thorough understanding of the “Technical Basis
for the Derivation of Equilibrium Partitioning Sediment
Guidelines (ESGs) for the Protection of Benthic
Organisms: Nonionic Organics” (U.S EPA, 2000c), the
ESG documents for endrin and dielcirin (U.S. EPA,
2000a,b), “Implementation Framework for Use of
Equilibrium Partitioning Sediment Gwdclincs (ESGs)”
(U.S EPA, 2000d), “Interim Guidance on Determination
and Use of Water-Effect Ratios for Metals” (U.S. EPA,
1994),” Water Quality Standards Handbook” (U.S. EPA,
1983), “Guidelines for Deriving Numerical National
Water Quality Criteria for the Protection of Aquatic
Organisms and their Uses” (Stephan et al., 1985),
response to public comment on the “Guidelines for
Deriving Numerical National Water Quality Criteria for
the Protection of Aquatic Organisms and their Uses”
(U.S. EPA, 1985), and the response to public comment
on the proposed ESGs (U.S. EPA, 2000e) is
recommended. Importantly, these procedures for site-
specific modification of national ESGs should be used
only after expanded chemical monitoring of chemical
concentrations in sediments and interstitial water;
biological monitoring including toxicity tests, TIEs, and
faunal surveys; and other nsk assessment procedures
that have been conducted at the specific site.
preferably using a tiered approach.
The national ESGs have been developed
specifically for use in the 304(a) criteria program.
These guidelines are EPA’s best estimate of the highest
concentration of a substance in sediments that will
protect benthic (infaunal and epibenthic) organisms
including macroinvertebrates and fishes.
The U.S. EPA, Office of Science and Technology
(OST), recognizes and has encouraged the potential use
of sediment guidelines by other EPA programs.
Appropriate use of the site-specific ESG in these
programs should be obtained from the implementation
guidance developed by that program for inclusion in
the “Implementation Framework for Use of Equilibrium
Partitioning Sediment Guidelines (ESGs)” (U.S. EPA,
20000.
1.2 Rationale for Procedures Used to
Develop Site-Specific Guidelines
National ESGs may be under- or overprotective if
(1) the benthic (infaunal and epibenthic) species at the
site are more or less sensitive than the benthic and
water column species included in the national criteria
dataset or (2) the sediment or chemical quality
characteristics at the site alter the bioavailability and,
consequently, the toxicity of the sediment-bound
chemical relative to that predicted by the equilibrium
partitioning (EqP) theory. Therefore, it is appropriate
that site-specific guidelines procedures address each of
these conditions.
This document recommends the use of the
Resident Species Deletion/Substitution Procedure to
adjust the national ESG for the sensitivity of species
found at the site. It is similar to the Recalculation
Prc edure published for use as a means to modify
national water quality criteria (WQC) values (U S. EPA,
1983, 1994). This approach permits deletion of certain
toxicological data on (1) water column species, (2)
nonresident benthic species, and (3) water column life-
stages of a resident species having both benthic and
water column life-stages. For example, although water
column species have sensitivities similar to those of
benthic species overall (Di Toro et al., 1991),
sensitivities of water column species at a site may differ
from those of benthic species found there. The
toxicological data on these species may not be
applicable to the derivation of a site-specific guideline;
1-1
-------
therefore, these data can be deleted. Furthermore, the
national criteria dataset may contain data for benthic
fauna that are particularly sensitive (e.g., certain
amphipods, penaeid shrimp, or mysids) or Insensitive
(e g ,certain adult polychaetes or molluscs) to some
chemicals. If they do not occur at a particular site, their
sensitivities may nof be representative of those species
expected to be found there, and toxicological data on
them can be deleted. When resident organisms such as
echinodernis, molluscs, or crustaceans have both
benthic and water column life-stages, and both have
been tested, data from tests with the benthic life-stage
are most relevant to the site-specific ESG, and data on
water column life-stages can be deleted When
nonresident benthic species or water column life-stages
of resident species having a benthic life-stage are likely
to be toxicologically related to untested resident
benthic species because of their taxonomic
relationship, deletion of acute toxicity data on them is
prohibited. However, it should be noted that deletion
of toxicological data may result in loss of taxonomic
representation required to meet the minimum database
for deriving WQC (Stephan et aL, 1985). These WQC
are used to derive the national ESG. For this reason,
additional testing may be required. Furthermore, given
the rules of this procedure, EPA strongly encourages
that additional tests be conducted with resident
benthic species to permit replacement of data on
surrogate species or life-stages.
This document recommends the use of the
Bioavailability Procedure as a means to replace the
national ESO when there are differences in the
bioavailabihty of the chemical in unique sediments.
These unique sediments can be identified by measuring
the chemical both in sediment and dissolved in
interstitial water, then comparing the resultant partition
coefficient with the organic carbon partition coefficient
(Koc) in the sediment guidelines document. Through
use of this procedure, the bioavailability concentration
of the chemical in interstitial water can be quantified for
comparison to the WQC final chronic value (FCV)
found in the chemical-specific ESG documents for
nonionic organic chemicals
The reason for using the Bioavailability Procedure
is that, although a variety of sediments have been
tested that demonstrate the applicability of the EqP
approach to a wide array of sediments (U.S EPA,
2000c), at certain unique sites sediments do exist where
EqP theory does not accurately predict partitioning.
Unique sediment characteristics, chemical speciation,
or chemical form may make the guidelines chemical
more or less bioavailable, thereby altering the toxicity
of the sediment (for further detail, see Section 4.1.3 in
the Technical Basis Document [ Ti S EPA, Z000cJ) For
example, in some sediments the partitioning of PANs
cannot be explained by standard models of equilibrium
partitioning to organic carbon (Maruya et al , 1996;
McGroddy et al , 1996) Instead, accurate predictions
of partitioning behavior may require the use of both a
Koc and a soot carbon partition coefficient (Gustafson
et al , 1997). Quantification of partitioning at these sites
requires measurement of the concentration of the
nonionic organic chemical in interstitial water and
sediment
In cases where it is necessary to identify causative
chemicals when toxicity is indicated by bioassays or
other tools, EPA recommends sediment-specific nsk
assessments be conducted using a tiered approach
This assessment may include expanded monitoring of
chemical concentrations in sediments and interstitial
water; biological monitoring including toxicity tests and
fauna I surveys (Swai-tz et al., 1994), and TIEs (Ankley et
al , 1991; Hoet al., 1997); and otherriskassessment
procedures conducted at the specific site. These
studies are recommended pnor to conducting the site-
specific ESG modification procedures to identify
chemicals causing observed effects and partitioning
not predicted by EqP theory. In the context of the tests
used in this risk assessment, it is important to recognize
that national ESGs are derived to provide estimates of
the sediment concentrations of specific substances
that are expected to protect conui unities of benthic
organisms from chronic effects that are applicable
across sediments—a goal that cannot be attained using
other assessment methods.
Studies conducted to modify site-specific WQC
have demonstrated that, if up-front planning with all
stake-holders had occurred before beginning each site-
specific study, the results of these studies could have
been significantly improved (Brungs, 1992) Therefore,
we strongly recommend that users of these guidelines
for developing site-specific ESGs consult early, and
closely, with the appropriate EPA Regional Office,
Office of Science and Technology, and Office of
Research and Development concerning the design and
conduct of these procedures. In addition, experience
with the use of the initial guidance for conducting site-
specific WQC adjustments (U S. EPA. 1983) has
identi fled improvements in the procedures required to
make the resultant site-specific criteria more appropriate
and less costly to derive (U.S. EPA, 1994). EPA
believes that application of these site-specific ESG
procedures will identify improvements that will require
modification over time. Because these procedures are
1.2
-------
scientifically complex, it is important that they be
conducted only by those who are well qualified and
experienced.
1.3 Definition of Site of Concern and
Resident Species at a Site
The aerial distribution of sediments that exhibit
toxicity to benthic organisms, or exceed the national
ESG, defines the site of concern. In the context of site-
specific ESG derivation, the concept of site must be
consistent with the requirements of the Resident
Species Deletion/Substitution Procedure or the
Bioavailability Procedure.
Derivation of a site-specific ESG based on species
sensitivity differences requires identification of
resident species expected to occur at the site. To
identify the species expected to occur at the site where
sediments exceed the ESG, a spatially larger area, as
well as temporal changes in fauna, must be considered.
The reason for this is that species may occur
permanently, seasonally, or intermittently at the site and
may be excluded from the site because of existing
temporary conditions, including pollution. Therefore,
the creation of a list of resident species might possibly
require knowledge of those species occurring in
adjacent water bodies or even in the entire ecological
province. Species not occurring at the site, due for
example to anthropogenic causes, must be included in a
list of resident species because they would likely return
if the pollutants or other conditions causing impacts
were removed. Therefore, identification of resident
species must include consideration of species found at
the immediate site of concern overtime, at other similar
sites, and so on, and may include entire biogeographic
provinces. If the sediment is to be moved, the species
resident at the site where sediments will be placed
should be included as resident species.
The spatial extent of the site, as applied to the
Bioavail ability Procedure, includes only the area
containing sediments that exceed the ESG. Of
particular concern are those sediments from the site
that exceed the ESG and are believed to be unique
because of sediment characteristics or chemical form
that may violate partitioning assumptions that are
fundamental to the sediment guidelines.
In case site-specific ESGs are deemed necessary
for purposes such as deriving permit limits and
identifying causative chemicals for toxicity, EPA
recommends preliminary site-specific evaluations prior
to initiation of these site-specific modification
procedures. For example, these procedures should not
be used until the horizontal and vertical extent of
sediments exceeding the ESO and the magnitude of the
exceedance is determined. These monitoring studies
can also be used to (1) determine if the partitioning of
the chemical to sediments is as predicted by EqP (e.g.,
for nonionic organic chemicals) by comparing the ratio
of the sediment concentration and the interstitial water
concentration with the Koc in the ESG document, (2)
identify the chemical cause of the observed toxicity, or
(3) determine if the toxicity of the sediment to the
tested species is predicted by EqP theory. All of these
can help determine if application of these site-specific
ESG procedures will likely decrease or increase the
national ESO.
1-3
-------
Section 2
Procedures for Conducting
Site-Specific ESG Modificatioas
2.1 Resident Species De etionJSubstjtutjon
Procedure
The Resident Species Deletion/Substitution
Procedure Is intended to result in a site-specific ESG
that appropriately adjusts the national ESG when there
are pertinent differences in the sensitivities of benthic
organisms that occur at the site from those organisms
used to derive the national ESG concentration. This
procedure follows that found in “Appendix B
Recalculation Procedure” of “Interim Guidance on Use
of Water-Effect Ratios for Metals” (U.S. EPA. 1994).
2.1.1 Rationale for Use of the Resident
Species Deletion/Substj j,jjo Procedure
This procedure is relevant for site-specific
modification of national ESGs bccause(1) sensitive or
insensitive benthic or water column species used to
derive the national £50 may not occur at the site, (2)
water column species or water column life-stages of
species that also have benthic life-stages that do occur
at the Site may not be relevant to the ESG derivation, or
(3) water column species and nonresident benthic
species may be toxicological surrogates for
taxonomically related but untested resident benthic
species or benthic life-stages of water column species.
The procedure considers the need to retain acute
values for nonresident benthic species or resident and
nonresident water column life-stages of benthic
species as toxicological surrogates for taxonomically
related but untested resident benthic species. The
rules that permit deletion of data are intentionally
restrictive because national databases often contain
data for only a relatively small number of genera and
deletion of data on nonresident species expected to
represent the sensitivities of untested resident species
must be avoided. Toxicity testing with resident benthic
species may be needed to complete minunum database
requirements for deriving guidelines. EPA encourages
testing of resident benthic species to permit deletion of
acute values for water column or nonresident benthic
species that serve as surrogates for untested resident
benthic species. In addition, it is important to obtain
data on recreationaily important, commercially
Important, and endangered or threatened species found
at the site.
For the purposes of this site-specific guidelines
document, resident organisms that “occur at the site”
are defined as those benthic species, genera, families,
orders, classes, or phyla of organisms that would be
expected to occur periodically or commonly at the
location where sediments contain chemicals in excess
of the £50. However, note that determining the species
expected to occur at the site will require expanding the
definition of site. This includes organisms that would
be expected to occur continually, seasonally, or
intermittently; those now absent because of
anthropogenic causes, and those that will be used as
toxicological surrogates. Organisms absent because of
physical changes, such as the impoundment of rivers,
are not considered resident. Creation of a list of
resident species will require the use of hIstorical
species lists for the site and, possibly, biological
assessment databases from nearby reference sites.
Enlisting the help of experts on local aquatic fauna is
suggested to create the resident species list.
Use of this procedure may increase, decrease, or
fail to change the national guideline value. If highly
sensitive species are not present at the site, an increase
in the guideline value is likely. If the number of acute
values is decreased, the guideline value will likely
decrease. Additional testing may reveal uniquely
sensitive or resistant species that could lower or raise
the guideline value. Because water column and benthic
species have similar sensitivities (Di Torn et al . 1991;
U.S. EPA, 2000c), deletion of acute values for certain
water column species or life-stages, and replacement
with newly obtained data on benthic organisms would,
on the average, not be expected to markedly alter the
guideline value.
2-1
-------
2.1.2 Details of the Resident Species
Deletkn/Subszilution Procedure
The basic principle of the Resident Species
Deletion/Substitution Procedure is to permit deletion of
all acute values for nonresident benthic species/life-
stages and water column species/life-stages when
acute values for all resident benthic species/life-stages
in a family have been tested. While implementing this
procedure, EPA encourages additional testing to
overcome conservatism in rules that prohibit deletion
of acute values that may be surrogates for acute values
of untested resident benthic species in a family. Ten
rules MUST be foHowed:
1. Literature search: A search MUST be conducted
of the scientific literature and unpublished reports
available since the date of the literature search for
the ESG document to obtain all acceptable acute.
chronic, and other toxicity data from water-only
and sediment toxicity tests. Of particulai interest
are data such as those in Section 3, Section 4, or
Appendix A of the chemical-specific ESG
documents. The toxicity test results MUST be
subject to rules for data acceptability found in
Stephan et al. (1985), or subsequent guidance. The
most important component of the review process is
that a qualified reviewer MUST use good judgment
in the review of data, experimental designs, and
methods used. This process MUST include both
published and unpublished data. Discarding good
data needs to be avoided. Rejection of bad data is
REQUIRED. The resultant acute toxicity dataset is
the new “national database.” The deletion process
that follows pertains only to acute toxicity values,
and the resultant database is termed the “site-
specific database.” (In the future, EPA intends to
develop a database of toxicity test results that
have been screened for applicability to sediment
guidelines derivation. Until this database becomes
available, those wishing to derive site-specific
ESGs MUST conduct the literature search to obtain
the new national database.)
2- Applies to ALL data: In all cases, deletion and
substitution decisions MUST apply to the entire
national database, not Just to the data for sensitive
species
3. Resident benthic species in a class, order, or
phylum hen’e no: been tested but acute values for
nonresident species in that class, order, or phylum
are available. If the national database contains
acute values for benthic or water column life-
stages of species in a class, order, or phylum from
which resident benthic species have not been
tested, the site-specific database MUST contain all
data for species in that class, order, or phylum
found in the national database.
4. All resident benthic species in a family tested: If a
‘family contains one or more benthic genera that
occur at the sith, and if the national database
contains every one of the resident species in these
genera, the site-specific database MUST contain
every one of these species that occur both at the
site and in the national database, but MUST NOT
contain any nonresident species in the genus or
nonresident genera in the family.
5. Not all resuienr bent hic species in a family tested:
If a family contains one or more benthic genera that
occur at the site, but the national database does
NOT contain every one of the resident benthic
species in each genus, the site-specific database
MUST contain all of the species in the national
database that are in that family.
6 Benthic life-stages of all resident species in a
family tested and waler column ljfe-stages of one
or more of these resident species tested: If a family
that occurs at the site contains one or more genera
with species having both benthic and water
column life-stages, and if the national database
contains acute values on the benthic life-stages for
every one of the resident species and acute values
for water column life-stages for one or more of
these species, the site-specific database MUST
contain every one of these acute values for the
benthic life-stages of the species that occur at the
site, but MUST NOT contain any acute values for
nonresident benthic species or life-stages or acute
values for the water column life-stages of any
species in the family.
7. Not all benthic life-stages of resident species in a
family tested and nonresident benthic l(fe-swges
or water column life-stases of resident or
nonresident species have been tested: If one or
more genera in a family that occurs at the site
contain species with both benthic and water
column life-stages, but the national database does
NOT contain acute values on the benthic life-
stages for every one of the resident species in all
resident genera, the site-specific database MUST
contain acute values for all benthic and water
column life-stages for resident and nonresident
species in all genera that are in the national
database.
2-2
-------
8. Minimum data requirements. If the site-specific
database does not meet the minimum database
requirements in the “Guidelines for Deriving
Numerical National Water Quality Cnteria for the
Protection of Aquatic Organisms and Their Uses”
(Stephari eta!., 1985), a site-specific sediment
guideline valuecan not be derived and the national
sediment quality guideline value applies to the site
until additional acceptable toxicity tests are
completed that meet the minimum data
requirements
9. Required and optional toxicity i’es:ing: Toxicity
tests MUST be conducted to complete minimum
data requirements for deriving the WQC FCV or to
ensure that data are available on at least one
benthic species in each animal or plant class cntical
to the site and each resident benthic species, or an
acceptable surrogate species, listed as threatened
or endangered under Section 4 of the Endangered
Species Act (ESA). Toxicity tests can be
conducted on resident benthic species or benthic
life-stages of resident species for which only water
column life-stages have been tested to complete
data requirements that permit deletion of data on
nonresident benthic species and water column life-
stages of either resident or nonresident species
(see rules 3 to7 above) It may be most helpful to
repeat toxicity tests on four or more of the most
sensitive resident genera in the national or site-
specific databases using measured chemical
concentrations and improved testing methodology
to permit replacement of acute values from
previously published tests.
10. Critical species resting: If data are not available
for a critical resident benthic species that is
threatened, endangered, commercially important,
recreationally important, or ecologically important,
data should be generated for that species or an
acceptable surrogate species (see Stephan et a!.
[ 1985j for details on test requirements).
Step-by-step examples of the deletion procedure
used to modify national WQC, a procedure not
substantively different from this Deletion/Substitution
Procedure for modifying national ESGs, are illustrated
in Appendix B of the “Interim Guidance on
Determination and Use of Water-Effect Ratios for
Metals” (U.S. EPA, 1994) This deletion process is
designed to ensure the following.
a. Each benthic species, or benthic life-stage of a
species that has both benthic and water column
life-stages, that occurs both in the national dataset
and at the site also occurs in the site-specific
dalaset.
b. Each species having a benthic life-stage that
occurs at the site, but does not occur in the
national dataset, is represented in the site-specific
dataset by ALL species in the site-specific dataset
that are in the same genus.
c Each genus having species with a benthic life-
stage that occurs at the site, but does not occur in
the national dataset, is represented in the site-
specific dataset by ALL genera in the national
dataset that are in the same family
d. Each order, class, and phylum that occurs both in
the national dataset and at the site is represented
in the site-specific dataset by one or more benthic
or water column species in the national dataset that
are closely related to a species that occurs at the
site.
e. Testing is encouraged or reqt ired to add new acute
toxicity data to the site-specific dataset on critical
resident benthic species that are threatened,
endangered. commercially important, recreationally
important, orecolog caJly important, or to permit
deletion of data on nonresident benthic species.
2.1.3 Derivation of the Site-Spec /ic ESG
Following the Deletion/Substitution Procedure
above, the guidelines for the derivation of a FCV
(Stephan et al, 1985) must be applied to the site-
specific database. Species mean acute values (SMAVs)
and genus mean acute values (GMAVs) must be
calculated. If minimum database requirements are met,
except those that require water column species, a site-
specific final acute value (FAVSS) is calculated If an
acute value for a critical resident benthic species that is
threatened, endangered, commercially important,
recreationally important, or ecologically important is
lower than the FAV, this value becomes the FAV
Finally, the FAV is divided by the final acute—chronic
ratio (FACR) from the ESG document, or the new site-
specific FACR (FACR 55 ) derived using new chronic
data from the literature search, to derive the site-
specific FCV (FCVSS) Acute-chronic ratios (ACR.s) for
sensitive benthic species do not differ from those of
the entire .WQC database of acute—chronic ratios (U S.
EPA .2000c,e), therefore, the deletion procedure does
not apply to the chronic toxicity database for a
substance for which an ESO is available.
2-3
-------
The site-specific ESG, on an organic carbon basis,
is the product of the Koc from the ESG document and
theR2Vss
ESG = KocRV
This ESGoc and ihe procedures in Section 5 of the
relevant ESG document should be used to derive the
95% confidence intervals.
All steps in the derivation of a site-specific ESG
must be documented in a report that includes a table
listing (1) all species and their life-stages used to derive
SMAVs, (2) all species and life-stages deleted, (3) test
conditions of the SMAV and GMAV data used for
calculation, and (4) references for the source of the
acute values, This table should be similar to Appendix
A in the ESG documents. The new calculated FAVss,
FACRSS , FCV 55 , and ESGoc, should appear after the
tabular presentation of toxicity data. All toxicity data
on all aquatic resident animal and plant species,
especially critical resident benthic species that are
threatened, endangered, commercially important,
recreationally important, or ecologically important, must
be Listed to permit comparisons between their
sensitivities and the FAV orFCV. All other species
known to be resident to the site and the source of this
information must also be listed.
2.2 Bioavailability Procedure
The Bioavailability Procedure is intended to result
in a site-specific ESG that appropriately replaces the
national ESG when there are pertinent differences in the
bioavailability of the chemical in the sediment from the
site, due to partitioning phases in the sediment, in
addition to organic carbon, or the presence in the
sediment of undissolved chemical. These alternate
partitioning phases may include, but not be limited to,
interstitial dissolved organic carbon (DOC), pure
chemical, or soot carbon. This approach assumes that
the ‘true” bioavailable concentration can be
reasonably measured or estimated as “freely-dissolved”
chemical in the interstitial water, which can then be
compared with the WQC FCV. Sediments in which the
freely-dissolved interstitial water concentration is less
than the WQC FCV would not be expected to cause
toxicity to benthic organisms and are acceptable for
maintaining the presence of the benthic community.
2.2.1 Rationale for Use of the Biooi’ailabiliiy
Pro cedure
EPA’s sediment guidelines for nonionic organic
chemicals are based on the EqP model. This model
uses a two-phase approach: particulate-associated
chemical and dissolved interstitial chemical, where the
total concentration in sediment equals the
concentration in the particulate phase plus the
concentration freely-dissolved in interstitial water. If
alternate phases exist in a sediment, it is possible that
the EqP model for sediment guidelines may not du-ectly
apply. In these cases, the toxicity of the sediment
cannot be predicted from the two-phase carbon—.
normalized sediment concentrations and the
because, in addition to organic carbon, combustion
particles, pure chemical, or other properties of the
sediments at the site may alter bioavailability. For these
sediments, site-specific criteria modification using the
Bioavailability Procedure is warranted.
The Bioavailability Procedure compares the
bioavai [ able, freely-dissolved interstitial water
concentration with the WQC FCV found in the
sediment guideline document-, or the site-specific fmal
chronic value derived using the Resident Species
Deletion/SubstitutiOn Procedure above. If the
interstitial water concentrations are below the WQC
FCV, the concentration of the chemical is below the
site-specific ESO. The three approaches EPA
recommends for estimating or measuring the freely-
dissolved chemical concentration in interstitial water
require procedures appropnate for obtaining and
chemically analyzing interstitial water- The approaches
assume that the chemical is distributed into three
phases: freely-dissolved, DOC-associated, and
particulate. The Bioavailability Approach assumes that
the use of the two-phase based Koc in calculating the
freely-dissolved concentration from sediment
concentrations is not appropriate for this sediment, and
furthermore, that the bioavailable concentrations can
be determined directly from an interstitial water sample
The analytical procedures presented below employ the
best presently available technology for obtaining
interstitial water, chemically analyzing interstitial water
chemical concentrations, and estimating or measuring
the freely-dissolved concentration of the chemical.
2-4
-------
2.2.2 DetaiLs of the Bioavailability Procedure
The problem of adequately collecting and
processing interstitial water samples is well
documented (Adams, 1991, Schults c i al, 1992; Ankley
and Schubauer-Berigan, 1994, ASTM, 1994; Oxtetich
and Schults, 1998) Artifacts from the procedures can
preclude accurate determination of interstitial water
contaminant concentrations The following procedures
are recommended to minimize effects ofinterstitial water
sample collection and processing for nonionic
organics
2 2.2.1 Sampling Interstitial Water
In general, centrifugation without subsequent
filtration results in the highest concentrations of metals
and nontonic organic compounds in interstitial water
from fine-grained, high water content sediment.
Because the objective of centrifugation is to obtain
interstitial water containing material smaller in diameter
than that which would pass through a O.45 cm filter (i.e.,
only the “soluble fraction”), any combination of
gravitational force (speed with effective radius) and
time that would settle the particles of greater effective
diameter to the sediment—tntersiitia l water interface
would be acceptable. For example, the following
recommended procedure resulted in 25 to 60 mL of clear
interstitial water from several industrialized waterways
including the Lauritzen Channel in northern San
Francisco Bay (Lee et al., 1994; Swartz et aL, 1994). A
150 g portion of wet sediment in a 150 mL glass
centrifuge bottle (Corex, Corning®) is spun at 5,000 rpm
(2,590-4,080 x g) in a fixed angle rotor (GSA, Sorvall®)
for 90 ruin at 4°C to obtain maximum volumes. When
completed, the centrifuge bottle is back-lighted and the
interstitial water is gently aspirated through Teflon®
tubing (drawn to a fine point) and placed deep into the
bottle next to the sedimenUwater interface. The
interstitial water passes through a stainless steel needle
directly into a glass vial This procedure has been
shown to reduce losses of organic constituents
(Ozi-etich and Schults, 1998). At this point, subsamples
can be taken for measurement of DOC (—3 mL). The
DOC-associated components (12-40 mnL) (Landrum et
aL, 1984; Ozretich et at, 1995) and the remaining
interstitial water (12—40 rnL) can be extracted in the
receiving vial for the determination of the total chemical
concentration (freely-dissolved fraction plus the
fraction bound to dissolved DOC material). Collecting
and subsampling the interstitial water must be done
within 2 hours to avoid complications from the
potential formation of de novo particles from oxidation
of reduced iron. It is clear that cleanly sampled
interstitial water is important, as the presence of a
particle of sediment could result in erroneously high
concentrations; on the other hand, if the time periods
before extractions are long or filtering and excessive
sample handling has occurred, erroneously low
concentrations would result as the chemicals are
sorbed to surfaces
2.2.2.2 Quantification of Dissolved and DOC-
Associated Phases
Once an adequate interstitial water sample has
been obtained, the quantity of contaminant present
must be accurately determined. Liquid-liquid (L-L)
extraction methods are routinely used to extract total
water samples and the DOC-associated fraction.
Commonly used L-L procedures (U.S. EPA, 1986) for
total water samples include the use of separatory
funnels (Method 3510C) and, when emulsions are
encountered, continuous extraction (Method 3520C).
PAils and chlorinated pesticide compounds are
typically quantified in I mLexti-acts from 1 Lsamples
by GCIMS (Method 8270C) in the scan mode with
qua niitation limits of 10 ug/L (PAl-Is), which exceeds
the solubility of many of the higher molecular weight
compounds for which these combined methods were
developed. Clearly, the recommended volumes and
mass spectrometer operational conditions of these
standard procedures are not adequate to quantify the
same compounds in easily obtained volumes of
interstitial water at concentrations near their WQC
FCVs. Alternatively, the gentle L-L extraction
procedure used for small volumes of interstitial water is
recommended (Ozretich et al., 1995), because itis
conceptually similar to continuous extraction in
providing long solvent-sample contact time while
eliminating emulsions. In addition, it uses fewer
extraction solvents and rio elaborate, hard-to-clean
glassware. Because the need to do a site-specific
determination of freely-dissolved interstitial water
concentrations is related to concerns regarding the
applicability of carbon—normalized concentrations of a
specific compound, the mass spectrometer need not be
operated in the scanning mode, but may be optimized
only for the mass fragmentation ions of the compound
of concern by operating in the selected ion mode, and
limiting the ions to 2—5 with maximum dwell times, as is
used for chlorinated dioxins and furans (Method 8280)
(U.S. EPA. 1992). By combining these mass
spectrometer modifications with smaller sample sizes
reduced to smaller volumes (50—250 pL) but larger
injection volumes (2—5 L; instrument dependent),
sample quantitation limits on the order of 10—50 ngfL
can be achieved (Ozretich et al , 1995)
2-5
-------
The bioavailable interstitial water concentration of
a chemical can be de.terntined in the following three
ways.
1. It can be assumed that the total interstitial wa ler
concentration (C, ) for a nonionic organic
chemical with a low to intermediate octanol —water
partition coefficient (ROW) value is equivalent to
the dissolved concentration; that is, the freely-
dissolved interstitial water concentration equals
the total dissolved interstitial watts concentration.
However, this approach may be problematic
because high concentration of DOC can be present
in interstitial water. Nonionic organics are known to
bind to this material, causing a reduction in their
bioavailabilitiy. Therefore, a L-L extraction of
interstitial water would contain the freely-dissolved
and the DOC-associated chemical, overestimating
the true bioavailable concentration. The
magnitude of the overestimate would depend on
the affinity of the DOC for the chemical of interest.
This affinity is represented by the partition
coefficient which is the ratio of the chemical
concentration bound to the DCC to the freely-
dissolved interstitial water concentration.
2. Ii can be determ ined that the freely -dissolved
interstitial waterconcentration is the difference
between the total interstitial water concentration
and the DOC-associat.ed concentration. This
method depends on the DOC-associated
concentration being operationally defined and
limited by the methodology (e.g., the separation of
total and bound fractions byCl8 columns)
(Landruinetal . 1984;Ozretichetat, 1995).
However, use of this procedure doubles the
number of samples that need to be taken and
analyzed, and may require monitoring of DCC
retention (Ozretich et aL, 1995). When using a
similar procedure to separate the DOC-associated
chemical, the freely-dissolved concentration can be
directlyineasured(Burgessetal., 1996). ThLs
approach should be used only if acceptable
concentration mass balances (approximately 90%)
of the DOC, dissolved, and total chemical are
available (R.M. Burgess, U.S EPA, Narragansett,
RI, personal communication).
3. it can be calculated from the total concentration
using the DOC concentration and the K c of the
compound from Equations 2-2 and 2-3, where the
freely-dissolved (bioavailable) interstitial water
chemical concentration is
Q= C /(DOCK + 1)
(2-2)
and the percentage of the total compound that is
freely-dissolved is
%Q=1/DOCK + l)x 100
(2-3)
This method depends on determination of DOC
(kilL) and Determining the concentration of
DOC in water is routine. However, identifying valid
values is problematic at this time.
Generally, it would be inappropriate to useK to
represent the partition coefficient of a chemical to DOC
material in calculating freely-dissolved concentrations
because particulate organic matter, represented by K ,
is generally described as very nonpolar and insoluble
in interstitial water. Conversely, dissolved or DOC,
represented by K c, is relatively more polar and
soluble in interstitial water (Chiou et aL, 1986).
Fundamental differences in solubiity of these types of
organic carbon in sediments will most likely also cause
differences in the magnitude of their respective
partition coefficients bra given chemical. Therefore,
they should not be used interchangeably.
When available, K 1 values have been plotted
versus values for chemicals with log 10 K 0 values
<65, and a generally linear relationship is observed
(Ozretich et al., 1995; Burgess et at, 1996). Forexample.
Ozretich et at (1995), using the C-iS separation
technique, found the following relationship (Equation
2-4) between published Kow and measured K
values of multiple PARs and chlorinated hydrocaxbons
that were placed in interstitial water and allowed to
equilibrate with unfractionated DOC.
log 1 0 K 0 = 0.907 lOZia Kow 0.75l
(2 -4)
Using this equation. computed K values from
theendrin anddieldrinESGdocuinents werecoinpared
with values (Table 2- i), and the percentare of the
total compound that is freely-dissolved, calculated
using Equation 2-3, was determined for a range of DOC
concentrations that are likely to be encountered in
interstitial water (Table 2-2). The greatest percentage of
a guideline chemical that would be bound to DOC
material using Kooc is approximately 50% for dieldrin
2.2.2.3 Calculating the Freely-Dissolved,
Bioavai lable Concenirasion
2-6
-------
(log 10 K 0 =5 37)at7OmgDOCIL Using Kocin
Equation 2-4, approximately 93% of dieldrin would be
computed to be bound at this DOC level. Therefore,
using the total concentrations as bioavailable would
overestimate the freely-dissolved concentration by a
factor of 14 if partitioning were assumed to be more
soil-like using K in Equation 2-2 orby a factor of 2
using Kooc
For the purposes of this document, it is
recommended that Equation 2-4 be used with Equation
2-2 to calculate the Cd. because KD is more
representative of binding to dissolved DOC material
than K .
2.2.3 Derivation of the Site-Spec fic ESG
l’his calculated or measured Cd is compared with
the WQC FCV from the individua l ESG documents. If
the freely-dissolved interstitial water concentration is
less than the FCV, toxicity would not be expected and
the sediment would be acceptable for maintaining the
presence of benthic organisms. Alternatively, the
interstitial water concentration can be compared with
the FCV derived using the Resident Species Deletion/
Substitution Approach.
Table 2-1. Computed organic carbon—normalized partition coefficients
Compound j• 0 g 10 j 0 a Log 10 K b
1j)gIoK C
Endrin 5 06 3.84
Dieldrm 537 4.12
4.97
528
From corespoilding ESO documents
bDeflved using Equation 2-4.
C om colrcspoudiog ESO documents using. log ioKoc = 0.983 x 1og 10 K 0 + 0 00028
Table 2.2. Solutions to Equation 2-3 using K values computed from Equation 2-4
DOC Endrm
(mg/L) (% frcc)
Dicidrin
0 100
(% free)
100
5 97
94
10 94
88
15 91
83
20 88
79
25 85
75
30 83
72
40 78
65
50 74
60
60 71
56
70 67
52
2-7
-------
Section 3
References
Adams DD. 1991. Sediment pore water sampling. In
Mudroch A, MacKnight SD, eds, Handbook of
Techniques for Aquatic Sediments Sampling. CRC
Press,BocaRaton,FL, pp 171—202.
American Society for Testing and Materials (ASTM).
1994. Standard guide for collection, storage,
characterization, and manipulation of sediments for
toxicological testing. E 1391-94. ASTM 1994 Annual
Book of Standards. Philadelphia, PA.
Ankley GT, Schubauer-Berigan MK. 1994. Comparison
of techniques for isolation of sediment pore water for
toxicity testing. Arch Environ Coniam Toxicol 27:507—
512.
Ankley GT, Schubauer-Berigan MK, Dierkes JR.
LukasewyzMT. 1991. Sediment toxicity identification
evaluation: Phase I (characterization), Phase II
(identification) and Phase ill (confirmation)
modifications of effluent pzpcedures. EPA 60CV6-9 1/007.
U.S. Environmental Protection Agency, Washington,
DC:
Brungs WA. 1992. Synopsis of water-effect ratios for
heavy metals as derived for site-specific water quality
criteria. Final Report from Dynamac Corporation to
U.S. Environmental Protection Agency, Washington,
DC:
Burgess RM. McKinneyRA, Brown WA, Quinn JG.
1996. Isolation of marine sediment colloids and
associated polychiorinated biphenyls: An evaluation
of ultrafiltration and reverse-phase chromatography.
Environ Sci Technol 30:1923—1932.
Chiou CT, Malcolm RL, Brinton TI, Kile DE. 1986.
Water solubility enhancement of some organic
pollutants and pesticides by dissolved hurnic and
fulvic acids. Environ Sd Technol 20:502—508.
Di Toro DM, Zarba CS, Hansen DJ, Berry WJ, Swaiiz
RC, Cowan CE, Pavlou SP, Allen HE, Thomas NA,
Paquin PR. 1991. Technical basis for establishing
sediment quality criteria for nonionic organic chemicals
by using equilibrium partitioning Environ Toxicol
Chem 1&1541—1583.
Gustafson 0, Haghseta F, Chan C, MacFart ane J,
Gschwend P. 1997. Quantification ofthedilute
sedimentary soot phase: Implications for PAH
speciation and bioavailability. Environ Sci Technol
31:203—209.
Ho KT, McKinney RA, Kuhn A, Pelletici MC, Burgess
RM. 1997. Identification of acute toxicants in New
Bedford Harbor sediments. Environ Toxicol Chem
16:551—558.
Landrum PF, Nihart SR. Eadie BJ, Gardner WS. 1984.
Reverse-phase separation method for determining
pollutant binding to Aldrich humic acid and dissolved
organic carbon in natural waters. Environ Sc: Technol
18:187-192.
Lee II H, Lincoff A, Boese BL, ColeFA, Ferraro SP,
Lamberson ID, Ozsetich RJ, Randall RC, Rukavina KR,
Schults DW, Sercu KA, Specht DT. Swartz RC, Young
DK. 1994. Ecological risk assessment of the marine
sediments at the United Heckathorn superfund site.
EPA-600i ’X-941029. Final Report. Environmental
Research Laboratory, U.S. Environmental Protection
Agency, Newport, OR.
Maruya KA, Risebrough RW, Home All 996.
Partitioning of polynuclear aromatic hydrocarbons
between sediments from San Francisco Bay and their
porewaters. Environ Sci Technol 30:2942—2947.
McGroddy SE, Farrington JW, Gschwend PM. 1996.
Comparison of the in situ and desorption sediment-
water partitioning of polycyclic aromatic hydrocarbons
and polychlorinated biphenyls. Environ Sci Technol
3&.172—177.
National Academy of Sciences (NAS). 1973. Water
quality criteria, 1972. EPA-R3-73-033. National
Academy of Sciences, U.S. Environmental Protection
Agency, Washington, DC.
Ozretich RJ. Schults DW. 1998. A comparison of
interstitial water isolation methods demonstrates
centrifugation with aspiration yields reduced losses of
organic constituents. Chenwsphere 36:603—615.
3-1
-------
Ozretich R i, Smith LM, Roberts PA 1995. Reverse-
phase separation of estuarine interstitial water fractions
and the consequences of C18 retention of organic
matter. Environ Toxicol Chem 14:1261—1272.
Schults DW, Ferraro SP, Smith LM, Roberts FA,
Poindexter CK. 1992. A comparison of methods for
collecting interstitial water for trace organic compounds
and metals analyses. Water Res 26:989—995.
Stephan CE, Mount DI, Hansen DJ, Gentile Jil,
Chapman GA, Brungs WA. 1985. Guidelines for
deriving numerical national water quality criteria for the
protection of aquatic organisms and their uses. PB8S-
227049. National Technical Information Service (NTIS),
Springfield, VA.
Swartz RC, Cole PA, Lamberson JD, Ferraro SP, Schults
DW, Deben WA, Lee H H, Ozretich RI. 1994. Sediment
toxicity, contamination, and amphipod abundance at a
DDT and dieldrin contaminated site in San Francisco
Bay. Environ Toxicol Chem 13:949—962.
U.S. Environmental Protection Agency. 1983. Does the
site-specific database meet WQC Guidelines
requirements? In Water Quality Standards Handbook.
Office of Water Regulations and Standards,
Washington, DC.
U.S. Environmental Protection Agency. 1985.
Appendix 13— Responses to public comments on
“Guidelines for deriving numerical national water
quality criteria for the protection of aquatic organisms
and their uses.” July 19, 1985. Federal Register
5&30793-30796.
U.S. Environmental Protection Agency. 1986. Test
methods for evaluating solid wastes: Physical/chemical
methods. Third edition, update ifi. SW -486.
Washington, DC.
U S. Environmental Protection Agency. 1987. Quality
cnteria for water, 1986. EPA 44 S-86-001. Office of
Water Regulations and Standards, Washington DC.
U.S. Environmental Protection Agency. 1994. Interim
guidance on determination and use of water-effect
ratios for metals. EPA-823-B-94-001. Office of Water,
Washington, DC.
U.S. Environmental Protection Agency. 1999. National
recommended water quality criteria—Correction. EPA-
822-2-99-001. April 1999. Washington, DC.
U.S. Environmental Protection Agency. 2000a.
Equilibrium partitioning sediment guidelines (ESGs) for
the protection of benthic organisms: Endrin. EPA-822.
R-O0-004. Office of Science and Technology,
Washington, DC.
U.S. Environmental Protection Agency. 2000b.
Equilibrium partitioning sediment guidelines (ESGs) for
the protection of benthic organisms: Dieldrin. EPA-822-
R-00-003. Office of Science and Technology,
Washington, DC.
U.S. Environmental Protection Agency. 2000c.
Technical basis for the derivation of equilibrium
partitioning sediment guidelines (ESGs) for the
protection of benthic organisms: Nonionic organics.
EPA-822-R-00-001. Office of Science and Technology,
Washington, DC.
U.S. Environmental Protection Agency. 2000d.
Implementation framework for use of equilibrium
partitioning sediment guidelines (ESGs). Office of
Science and Technology, Washington, DC.
U.S. nvironmental Protection Agency. 2000e.
Responses to public comment on the proposed
“Methods for the derivation of site-specific equilibrium
partitioning sediment guidelines (ESOs) for the
protection of benthic organisms” EPA-822-R-OO-007.
Office of Science and Technology. Washington, DC.
U.S. Environmental Protection Agency. 2000f.
Equilibrium partitioning sediment guidelines (ESGs) for
the protection of benthic organisms: Metal mixtures
(cadmium, copper, lead, nickel, silver, and zinc). EPA-
822-R-0O-005. Office of Science and Technology.
Washington, DC.
U.S Environmental Protection Agency. 2000g.
Equilibrium partitioning sediment guidelines (ESGs) for
the protection of benthic organisms: Polycyclic
aromatic hydrocarbon (PAN) mixtures. Office of Science
and Technology. Washington, DC.
U.S. Environmental Protection Agency. 2000h.
Equilibrium partitioning sediment guidelines (ESGs) for
the protection of benthic organisms: Nonionics
compendium. EPA-822-R-00-06. Office of Science and
Technology and Office of Research and Development,
Washington, DC.
3-2
-------
U.S. Environmental Protection Agency. 1998. Ambient
water quality criteria derivation methodology: Human
health. Technical support document, final draft EPA-
822-B-98-005. Washington, DC.
U.S. Environmental Protection Agency. 1999. National
recommended water quality criteria-correction. EPA-
822-2-99-001. April1999. Washington, DC.
U.S. Environmental Protection Agency. 2000a.
Implementation framework for use of equilibrium
partitioning sediment guidelines (ESGs). Office of
Science and Technology, Washington, DC.
U.S. Environmental Protection Agency. 2000b.
Equilibrium partitioning sediment guidelines (ESGs) for
the protection of benthic organisms: PAM mixtures.
Office of Science and Technology, Washington, DC.
U.S. Environmental Protection Agency. 2000c.
Equilibrium partitioning sediment guidelines (ESOs) for
the protection of benthic organisms: Dieldrin. EPA-822-
R-00-003. Office of Science and Technology,
Washington, DC.
U.S. Environmental Protection Agency. 2000d.
Equilibrium partitioning sedunent guidelines (ESGs) for
the protection of benthic organisms: Endrin. EPA-822-
R-00-004. Office of Science and Technology,
Washington, DC.
U.S. Environmental Protection Agency. 2000e. Methods
for the derivation of site-specific equilibrium
partitioning sediment guidelines (ESOs) for the
protection of benthic organisms: Nonionic organics.
EPA-822-R-00-002. Office of Science and Technology,
Washington, DC.
U.S. Environmental Protection Agency. 2000f.
Equilibrium partitioning sediment guidelines (ESGs) for
the protection of benthic organisms: Metal mixtures
(cadmium, copper, lead, nickel, silver, and zinc). EPA-
822-R-00-005. Office of Science and Technology,
Washington, DC.
U.S. Environmental Protection Agency. 2000g.
Equilibrium partitioning sediment guidelines (ESGs) for
the protection of benthic organisms: Nonionics
compendium. EPA-822-R-O0-06. Office of Science and
Technology and Office of Research and Development,
Washington, DC.
Voice TC, Rice CP, Weber WJ, Jr. 1983. Effect of solids
concentration on the sorptive partitioning of
hydrophobic pollutants in aquatic systems. Environ
Sd Technol 17:513—518.
Woodburn KB, Doucette WJ, Andren AW. 1984.
Generator column determination of octanol/water
partition coefficients for selected polychiorinated
biphenyl congeners. Environ Sci Tecluzol 18:457—459.
Wu SC, Gschwend PM. 1986. Sorption kinetics of
hydrophobic organic compounds to natural sediments
and soils. Environ Sci Technol 20:717—725.
Xing B, McGill WB, Dudas MJ. 1994. Cross-correlation
of polarity curves to predict partition coefficients of
nonionic organic contaminants. Environ Sd Technol
28:1929—1933.
8-6
------- |