[Federal Register Volume 59, Number 11 (Tuesday, January 18, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-1133]


[[Page Unknown]]

[Federal Register: January 18, 1994]


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Part II





Environmental Protection Agency





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Sediment Quality Criteria; Notice
ENVIRONMENTAL PROTECTION AGENCY

[OW-FRL-4827-2]

 
Sediment Quality Criteria

AGENCY: Environmental Protection Agency.

ACTION: Notice of Availability and Request for Comment on Sediment 
Quality Criteria and Support Documents.

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SUMMARY: Pursuant to section 304(a)(1) of the Clean Water Act, the U.S. 
Environmental Protection Agency (EPA) has developed, and is requesting 
public comments on, documents presenting proposed Sediment Quality 
Criteria for the Protection of Benthic Organisms for five priority 
pollutant (section 307(a)) chemicals, guidelines for deriving these 
criteria on a site-specific basis, and the technical basis for deriving 
the criteria. The criteria documents present data and criteria for 
acenaphthene, dieldrin, endrin, fluoranthene and phenanthrene, which 
were selected for their known toxicity, hydrophobicity, and 
persistence. EPA intends to publish each of the documents in final form 
after considering public comments, while the general regulatory role 
Sediment Quality Criteria play will be outlined in the Contaminated 
Sediment Management Strategy (CSMS) which will be available for public 
comment in the near future. The Agency is specifically soliciting 
comments on the scientific soundness of the criteria development 
methodology and the criteria themselves as opposed to their 
application. Comments received in response to this notice on the 
intended uses and implementation of the criteria will be taken into 
account in preparing the proposed CSMS and other guidance materials. An 
exception to this is the potential for the Sediment Quality Criteria to 
be used as Applicable and Relevant or Appropriate Requirements (ARARs) 
under CERCLA. The EPA particularly welcomes comment and discussion on 
the applicability and appropriateness of using the criteria as ARARs.

DATES: Written comments must be postmarked or submitted by hand on or 
before April 18, 1994.

ADDRESSES: Comments may be mailed or delivered to: Sediment Quality 
Clerk, Water Docket MC-4101, Environmental Protection Agency, 401 M 
Street SW., room L102 Washington, DC 20460. Commenters are requested to 
submit any references cited in their comments. Commenters are also 
requested to submit an original and 3 copies of their written comments 
and enclosures. Commenters who want receipt of their comments 
acknowledged should include a self-addressed, stamped envelope. No 
facsimiles (faxes) will be accepted.

FOR FURTHER INFORMATION CONTACT: Mary C. Reiley, Sediment Quality 
Criteria Program, Office of Science and Technology, Mail Code 4304, 401 
M Street SW., Washington, DC 20460, phone: 202-260-0658.

SUPPLEMENTARY INFORMATION:

I. Availability of Documents

    This notice announces the availability for public review and 
comment of draft documents proposing sediment quality criteria for the 
protection of benthic organisms for five priority pollutant chemicals, 
the methodology used to derive the criteria, and guidelines for 
modifying the criteria on a site-specific basis. The seven documents 
for which public comment is requested are:
     Sediment Quality Criteria for the Protection of Benthic 
Organisms: ACENAPHTHENE (EPA-822-R-93-013)
     Sediment Quality Criteria for the Protection of Benthic 
Organisms: DIELDRIN (EPA-822-R-93-015)
     Sediment Quality Criteria for the Protection of Benthic 
Organisms: ENDRIN (EPA-822-R-93-016)
     Sediment Quality Criteria for the Protection of Benthic 
Organisms: FLUORANTHENE (EPA-822-R-93-012)
     Sediment Quality Criteria for the Protection of Benthic 
Organisms: PHENANTHRENE (EPA-822-R-93-014)
     Technical Basis for Deriving Sediment Quality Criteria for 
Nonionic Organic Contaminants for the Protection of Benthic Organisms 
by Using Equilibrium Partitioning (EPA-822-R-93-011)
     Guidelines for Deriving Site-Specific Sediment Quality 
Criteria for the Protection of Benthic Organisms (EPA-822-R-93-017)
    Copies of the draft documents may be obtained upon request from the 
Office of Water Resource Center (202) 260-7786. These documents are 
also available for public inspection and copying during normal business 
hours at the Water Docket Room L-102 (basement) Environmental 
Protection Agency, 401 M Street, SW., Washington, DC 20460. For access 
to Docket materials, call (202) 260-3027 between 9 a.m. and 3:30 p.m. 
for an appointment. Copies of these documents are also available for 
review in the EPA Regional office libraries. For the Regional Office 
library in your area contact: EPA Library, (202) 260-3944. EPA's 
response to public comment will be available upon request from the 
Office of Water Resource Center (202) 260-7786. As provided in 40 CFR 
part 2, a reasonable fee may be charged for copying services.

II. Background Information

    Toxic contaminants in bottom sediments of the nation's lakes, 
rivers, wetlands, and coastal waters create the potential for continued 
environmental impact even where water column contaminant levels comply 
with established water quality criteria. In addition, contaminated 
sediments can have impacts on water quality even when additional 
pollutants are no longer being added by any other source. It is 
intended that sediment quality criteria be protective of benthic 
organisms and be used to: assess the extent of sediment contamination, 
aid in implementing measures that limit or prevent additional 
contamination, and identify when appropriate remediation activities are 
needed.
    Section 304(a)(1) of the Clean Water Act (33 U.S.C. 314(a)(1)), 
directs EPA to develop and publish criteria reflecting the latest 
scientific knowledge on the identifiable effects of pollutants on 
public health and welfare, aquatic life, wildlife and recreation. EPA 
has periodically issued ambinent water quality criteria guidance, 
beginning with the publication of ``Water Quality Criteria 1972.'' All 
criteria guidance through late 1986 was summarized in an EPA document 
entitled ``Quality Criteria for Water, 1986.'' EPA has subsequently 
published, from time to time, new ambient water quality criteria 
guidance for additional pollutants or revised existing criteria 
guidance.
    EPA's criteria documents are intended to provide a comprehensive 
toxicological evaluation of each chemical addressed therein, based on 
available information. For toxic pollutants, the documents tabulate the 
numeric acute and chronic toxicity information for aquatic life and, 
where sufficient information is available, derive the numeric criteria 
maximum concentrations (acute criteria) and the numeric criteria 
continuous concentrations (chronic criteria) that the Agency recommends 
to protect aquatic life resources. The documents also provide 
recommended criteria to protect human health. EPA has published numeric 
aquatic life criteria for 30 priority pollutants and human health 
criteria for 91 priority pollutants. Aquatic life criteria address 
potential water column impacts only.
    EPA is now proposing sediment quality criteria for five priority 
pollutant chemicals (endrin, dieldrin, fluoranthene, phenanthrene, and 
acenaphthene) that EPA has determined are present in the sediment of 
the Nation's waters and cause or have the potential to cause adverse 
effects to the water column and benthic assemblages and their 
hierarchical foodchains including humans. Pursuant to section 104 of 
the Clean Water Act, the Agency has conducted research, experiments and 
demonstrations and has studied the effects of contaminated sediment on 
freshwater, marine, and estuarine aquatic life. EPA used this 
information to develop the criteria proposed today, which represent 
EPA's first effort to develop sediment quality criteria. These five 
chemicals were selected because of their known toxicity, 
hydrophobicity, and persistence.
    EPA developed these proposed sediment quality criteria using a 
methodology called the Equilibrium Partitioning Approach which was 
selected after considering a variety of approaches that could be used 
to assess sediment contamination. Technical reviews of the methodology 
and supporting science was conducted by the EPA Science Advisory Board 
(SAB) in February 1989 and June 1992. Data collected in support of the 
ambient aquatic life water quality criteria or an equivalent data base 
were also used to derive the proposed sediment quality criteria. 
Sediment criteria concentrations are expressed as micrograms chemical 
per gram organic carbon and apply to sediments with  0.2% 
organic carbon; below this the criteria should not be applied because 
of significant scientific uncertainty associated with extrapolating to 
sediments with < 0.2% organic carbon.

III. Possible Uses of Sediment Quality Criteria

    The main purpose of this notice is to seek comment on the 
scientific and technical merit of the criteria and methodology. To 
place the criteria in context, this section discusses potential uses of 
the criteria.
    EPA is in the process of identifying and evaluating a range of 
possible uses to which final sediment quality criteria may be applied. 
For example, EPA is considering whether to use these criteria as a 
basis for water quality assessment reports under section 305(b), as a 
basis for total maximum daily loads under section 303(d), and water 
quality-based effluent limits in National Pollutant Discharge 
Elimination System (``NPDES'') permits under section 402, and/or as a 
possible standard in developing clean-up strategies under the Clean 
Water Act or other statutes. These and other possible uses are 
discussed below.
    Section 305(b) requires the states to assess the quality of their 
navigable waters in terms of the extent to which they meet the goals of 
the Clean Water Act. EPA proposes to encourage states, during these 
assessments, to identify areas with sediment contamination.
    Under section 303(c), states adopt water quality standards 
including criteria to protect designated uses. Final section 304(a) 
numeric sediment quality criteria guidance could be used by states in 
adopting State numeric sediment quality criteria designed to protect 
the public health or welfare, enhance the quality of water, and serve 
the purposes of the Act.
    Sediment quality criteria could become a basis for total maximum 
daily loads under section 303(d) and water quality-based effluent 
limits in NPDES permits under section 402. (Their use in NPDES permits 
is discussed in detail below). Pursuant to section 303(d), states are 
required to identify and establish total maximum daily loads for water 
where existing pollution controls are not stringent enough to achieve 
applicable water quality standards. Under section 301(b)(1)(c), permit 
writers are required to impose in NPDES permits any more stringent 
limitations necessary to achieve water quality standards. If a state 
has adopted water quality standards based on sediment quality criteria, 
and if those standards are not being achieved, then TMDLs are required 
(unless existing controls will remedy the impairment) and appropriate 
effluent limits need to be included in NPDES permits. In addition, even 
if the states do not adopt numeric sediment criteria as part of state 
water quality standards, the EPA section 304(a) criteria could still be 
used by State and Federal permit writers as a starting point under 40 
CFR 122.44(d)(1)(vi) to derive numeric water quality-based effluent 
limits as necessary to attain applicable narrative criteria (e.g., 
those that require receiving waters to be ``free from'' toxics). 
Indeed, many states, as part of their narrative criteria, have adopted 
prohibitions against objectionable sediment deposits. Similarly, the 
section 304(a) criteria could be used in state's TMDLs.

National Pollutant Discharge Elimination System Program

    In EPA's 1987 report, An Overview of Sediment Quality in the United 
States, municipal sewage treatment plants and combined sewer overflows 
were cited as sources of sediment contamination in all regions of the 
country. Chemical, steel, metal working and electroplating industries 
were also mentioned as sources in many areas as were engine and 
automotive facilities, nuclear energy producers, paper mills, 
tanneries, refineries and other petroleum industries, electrical 
component and capacitor manufacturers, and wood preservers. The Agency 
is compiling a national inventory of point and nonpoint sources of 
sediment contamination to assist in targeting at risk sites and 
facilities.
    In recognition of the role of contaminated sediments as a cause of 
impaired water quality, the NPDES permitting program is developing and 
field testing models predictive of the ambient quality of water and 
sediment. While existing water quality models may be quite helpful in 
understanding the sediment dynamics in specific waterbodies, they may 
be too complex to be routinely used by regulatory authorities to 
establish water quality-based effluent limits based on sediment quality 
criteria. The NPDES program is supporting development of a chemical-
specific sediment quality criteria-based effluent limit methdology and 
is testing its application. The NPDES program also intends to develop 
guidance on the procedure. EPA hopes that such a method will be 
sufficiently sophisticated to be reliable and defensible, yet require 
minimal data points and scientific extrapolations so that it can be 
routinely applied in a regulatory context.
    In addition to developing a sediment quality criteria-based 
permitting methodology, the NPDES program is supporting laboratory 
training, demonstrations, and guidance development on the assessment 
and control of bioconcentrating pollutants which, by nature, accumulate 
in sediments. It is also supporting development of acute and chronic 
sediment toxicity tests and sediment toxicity identification 
evaluations. The sediment quality criteria will advance all of these 
efforts by establishing a new tool for achieving the long-term goals of 
the Act.

Great Lakes Program

    Sediment quality criteria could also be used in connection with the 
Great Lakes program. For example, the Great Lakes Water Quality 
Agreement provides that the United States and Canadian governments will 
cooperate with State and Provincial governments to ensure that Remedial 
Action Plans (``RAPs'') are developed and implemented for specific 
Areas of Concern (``AOCs'') in the Great Lakes. The Great Lakes Water 
Agreement also calls for the establishment of compatible criteria 
between the two countries for the classification of sediment quality. 
Thus, EPA anticipates that Great Lake States and EPA Regions will use 
final sediment quality criteria for various purposes, including 
establishing priorities for sites needing further assessment, targeting 
areas for potential remediation and prevention efforts, and supporting 
the development of state water quality standards based on sediment 
quality criteria.
    In each of the designated AOC's located in the United States 
contaminated sediments have been identified as causing at least one of 
the 14 beneficial use impairments listed in the Great Lakes Water 
Quality Agreement. The RAPs are to specify the beneficial uses that are 
impaired, the remedial measures needed to restore beneficial uses, and 
an implementation schedule. For those AOC's already identified most of 
the Stage 1 RAPs (problem identification) have already been completed 
and most Stage 2 RAPs (remedial actions) are in preparation, therefore, 
the proposed criteria will be most applicable for the identification of 
future AOC's and development of their Stage 1 and 2 RAPs.
    The International Joint Commission (IJC) has published ``listing/
delisting criteria'' for adding and removing a site from the AOC list. 
The listing/delisting criteria refer to various tools to measure the 
impacts on beneficial uses, including the contaminant levels in fish 
and wildlife, numerical water quality criteria for surface waters, and, 
in the case of restrictions on dredging activities, the extent to which 
sediment contamination may exceed standards, guidelines, or IJC 
objectives. The EPA will look to the Great Lakes States to review 
sediment quality data for each AOC in relation to the possible 
impairment of beneficial uses and to consider 304(a) sediment quality 
criteria and any other more recent data or relevant site specific data 
to design preventive and remedial actions for contaminated sediment. 
For example, EPA in cooperation with Great Lakes States and the 
Canadian Federal and Provincial Governments, may use the sediment 
quality criteria as one means to prioritize sites for action by 
comparing the toxic contaminant concentration in the sediments to the 
most stringent of either Canadian or U.S. standards or guidelines.

Superfund Program Uses

    The SQC have been developed primarily to assist in pollution 
prevention and water quality control activities. Due to many factors, 
such as the potential for causing environmental damage through 
distrubing contaminated sediments, they are not intended as mandatory 
levels to be met in clean-up efforts. EPA recognizes that, in 
particular circumstances, it may be appropriate to use natural recovery 
as a sediment remediation tool. Superfund is primarily a remediation 
program concerned with the clean-up or remediation of sites that have 
been contaminated.
    The Superfund program expects to use SQC as a tool to evaluate 
sites that may require assessment and possible remediation. For 
example, if a site has been shown to exceed SQC levels, it may be given 
higher priority for assessment with the Hazard Ranking System (HRS) to 
help determine if the site should be added to the National Priorities 
List (NPL). NPL sites typically require long term remediation efforts. 
In general, the Superfund program expects to employ SQC for sites with 
sediment contamination as part of a tiered testing protocol.
    Given the above approach to the assessment of contaminated 
sediments, Superfund's approach is consistent with the conclusions of 
both the Science Advisory Board's November 1992 review of the criteria 
and the Agency: ``The use of SQC's as stand-alone, pass-fail criteria 
is not recommended for all applications.'' and ``* * * the 
inappropriate uses of the SQC's, such as mandatory target clean-up 
standards, [should be stated] unless additional site specific studies 
are completed.'' At the same time, SQC's might be considered water 
quality criteria as referenced in section 121(d)(2)(A) of CERCLA, and 
thus potential Applicable or Relevant and Appropriate Requirements 
(ARAR's). Similarly, if SQC are adopted by States as part of water 
quality standards, they could be considered as ARARs. The Agency 
requests comment on the appropriateness of the use of SQC as ARARs and 
if so what aspects of the remedial action they should affect.

RCRA Corrective Action

    The Office of Solid Waste will include the 304(a) sediment quality 
criteria as assessment tools in RCRA Facility Investigations (RFI's) 
guidance. Currently the guidance warns about potential sediment quality 
problems but does not recommend specific tests to evaluate the 
ecological and human health risks posed by contaminated sediments.

Other Programs

    A variety of other regulatory and nonregulatory programs are 
looking to sediment quality criteria as a benchmark for contaminated 
sediment evaluations. The dredging program (Sec. 404 of the CWA and 102 
of MPRSA), which is jointly implemented by the Army Corps of Engineers 
and the EPA, may incorporate sediment quality criteria into Tier II of 
the dredged material management plan which is currently under 
development. Other examples of potential sediment quality criteria uses 
are to: (1) Proactively monitor to ensure uncontaminated sediments 
remain uncontaminated; (2) predict the need to arrest increasing 
contamination before harm occurs; (3) establish the spatial extent of 
contamination to determine the potential costs/benefits of clean-up and 
remediation efforts; and/or (4) identify sources of contamination via 
toxicity identification evaluation (TIE) protocols that link toxic 
contaminants to sources. In some cases, sediment criteria alone would 
be sufficient to identify and to establish goals for remediation or 
clean-up of contaminated sediment. In other cases the sediment criteria 
should be supplemented with biological sampling and testing and more 
extensive chemical monitoring before decisions are made.
    Neither the Science Advisory Board nor the Agency believes the 
sediment quality criteria should be used as ``pass/fail'' criteria or 
mandatory clean-up levels for all programs. It is often more 
environmentally sound to allow clean sediments to cover contaminated 
sediments over time than to remove the sediments in question. The 
removal of contaminated sediments may in and of itself cause physical 
harm to bottom communities as well as cause resuspension and dispersion 
of the contaminant being removed. The costs of clean-up may also be 
prohibitive because of the level or areal extent of contamination and 
the disposal requirements for contaminated sediments. Therefore, EPA 
expects that the sediment quality criteria will be used in a tiered 
approach to evaluate the level and areal extent of sediment 
contamination and the risk associated with a variety of clean-up or 
remediation alternatives.
    In combination, the above authorities provide a comprehensive 
mechanism for monitoring, assessing and researching the effects of 
pollutants on the Nation's waters and regulating the discharges in 
order to eliminate or limit their potential impacts on water quality. 
EPA also expects to publish, in the near future, an EPA Contaminated 
Sediment Management Strategy, which will provide guidance on the 
application of the sediment quality criteria. Though not specifically 
requested at this time, comments received in connection with this 
notice that discuss implementation issues will be considered in the 
development of the draft strategy.

V. Description of Sediment Criteria Pollutants

    Criteria pollutants were selected for their known toxicity, 
hydrophobicity, and persistence. The following section lists each 
chemical, its CAS number, sediment quality criteria value expressed as 
ug pollutant per gram of organic carbon within the sediment, and a 
brief description of the chemical, its potential sources and uses. The 
criteria documents themselves provide details on the range of 
uncertainty that surrounds the criteria values provided below.

Acenaphthene

(CAS No. 83-32-9)
Sediment Quality Criteria Value:
    Freshwater: 130 g/goc
    Saltwater: 230 g/goc

    Dihydro-acenaphthylene or 1,8 ethylenenapthalene occurs in coal and 
is released during the high temperature carbonization or coking of 
coal. Acenaphthene is also used as a dye intermediate in the 
manufacture of plastics, insecticides and fungicides, and has been 
detected in cigarette smoke and gasoline condensates. It is a 
polycyclic aromatic hydrocarbon.

Dieldrin

(CAS No. 60-57-1)
Sediment Quality Criteria Value:
    Freshwater: 11 g/goc
    Saltwater: 20 g/goc

    Prior to the cancellation of its registration (1974), dieldrin was 
one of the most widely used chlorinated hydrocarbon pesticides. Prior 
to its cancellation (1974), aldrin was used in greater quantity than 
dieldrin but quickly transforms into dieldrin in the environment. The 
chemicals were primarily used to control insect pests on corn and later 
on citrus fruits.

Endrin

(CAS No. 72-20-8)
Sediment Quality Criteria Value:
    Freshwater: 4.2 g/goc
    Saltwater: 0.76 g/goc

    Endrin is a chlorinated hydrocarbon insecticide. Prior to its 
cancellation (1986) it was used in the agricultural chemical industry 
for the control of pests on fruits and vegetation.

Fluoranthene

(CAS No. 206-44-0)
Sediment Quality Criteria Value:
    Freshwater: 620 g/goc
    Saltwater: 300 g/goc

    Fluoranthene, a polycyclic aromatic hydrocarbon, is a combustion 
product produced by the pyrolysis of organic raw materials, such as 
coal and petroleum at high temperature. It is ubiquitous in the 
environment.

Phenanthrene

(CAS No. 85-01-8)
Sediment Quality Criteria Value:
    Freshwater: 180 g/goc
    Saltwater: 240 g/goc

    Phenanthrene is a polycyclic aromatic hydrocarbon, naturally 
present in coal and petroleum, and having some industrial uses. It is 
also formed as a combustion product.

V. Description of the Technical Basis for Deriving Numerical National 
Sediment Quality Criteria for Nonionic Organic Contaminants Using 
Equilibrium Partitioning

    The Technical Basis for Deriving Sediment Quality Criteria for 
Nonionic Organic Contaminants for the Protection of Benthic Organisms 
by Using Equilibrium Partitioning presents the research performed and 
data collected in the development of the equilibrium partitioning 
approach to deriving sediment quality criteria. (See Section I 
entitled: ``Availability of Documents''.)

VI. Description of Guidelines for Deriving Site-Specific Sediment 
Quality Criteria for the Protection of Benthic Organisms

    The Guidelines for Deriving Site-Specific Sediment Quality Criteria 
for the Protection of Benthic Organisms provides guidance on the 
methodology which is appropriate for modifying nationally applicable 
sediment quality criteria on a site-specific basis. The document 
details the procedures and data necessary to perform the modification 
that may be required because of unique sensitivities of site species or 
partitioning processes at the site. (See Section I entitled: 
``Availability of Documents''.)

Request for Comments

    EPA is soliciting comments on the scientific soundness of the 
criteria development methodology and the proposed criteria themselves. 
The sediment quality criteria, like the surface water quality criteria, 
are ambient criteria describing aquatic conditions which support 
designated uses. The merit and validity of these criteria must stand 
alone without regard to permit limit derivation, sediment remediation 
costs, etc. Specifically the Agency requests comment on the five 
sediment quality criteria documents described above, the document 
entitled ``Technical Basis for Deriving Sediment Quality Criteria for 
Nonionic Organic Contaminants for the Protection of Benthic Organisms 
by Using Equilibrium Partitioning'' and the ``Guidelines for Deriving 
Site-Specific Sediment Quality Criteria for the Protection of Benthic 
Organisms''. EPA is also interested in receiving comments on the 
following issues:
1. Site Specific Criteria Modifications
    Under section 304(a) a state may develop its own water quality 
criteria on either a state-wide basis or on a site-specific basis to be 
protective of unique waters. EPA is considering the same approach for 
the developement of sediment quality criteria. Section 131.11(b)(1) of 
EPA's regulations allows states to modify 304(a) criteria to reflect 
site-specific conditions, when adopting water quality standards based 
on such criteria guidance and EPA is considering allowing similar site-
specific modification for water quality standards based on EPA's 
sediment quality criteria guidance. Technical persons have identified a 
number of reasons both supporting and challenging the appropriateness 
of allowing site specific modifications to sediment criteria. EPA is 
particularly interested in receiving comments and ideas on site 
specific criteria modifications. A more detailed discussion of these 
issues can be found on this topic on page 99 of the Technical Basis 
document identified above.
2. Need for Separate Sediment Quality Criteria To Protect Fresh Water 
and Marine Species
    For certain chemicals (acenaphthene, dieldrin, fluoranthene, and 
phenanthrene), statistical analysis of all the data used in the 
derivation of water quality criteria revealed no significant 
differences in the relative sensitivity of fresh water and marine 
species. Further, there are no known chemical or physical properties of 
the above chemicals that would support a difference in toxicity and 
bioavailability between aquatic environments. (These comparisons do not 
hold for endrin.) However, EPA customarily has developed separate 
criteria for saltwater and freshwater to avoid having the sensitivity 
of species in one aquatic environment drive environmental decisions and 
regulation in the other environment. Although these sediment quality 
criteria are derived separately for freshwater and saltwater, EPA seeks 
comment on the appropriateness of a single sediment quality criteria 
applicable to both aquatic environments after first demonstrating 
equivalency of sensitivity (for these and future criteria).

Acenaphthene

Sediment Quality Criteria Value:
    Freshwater: 130 g/goc
    Saltwater: 230 g/goc

    This difference is less than a factor of 2.

Dieldrin

Sediment Quality Criteria Value:
    Freshwater: 11 g/goc
    Saltwater: 20 g/goc

    This difference is less than a factor of 2.

Fluoranthene

Sediment Quality Criteria Value:
    Freshwater: 620 g/goc
    Saltwater: 300 g/goc

    This difference is less than a factor of 2.

Phenanthrene

Sediment Quality Criteria Value:
    Freshwater: 180 g/goc
    Saltwater: 240 g/goc

    This difference is less than a factor of 2.

Endrin

Sediment Quality Criteria Value:
    Freshwater: 4.2 g/goc
    Saltwater: 0.76 g/goc

    This difference is approximately a factor of 5 which is 
statistically significant and would require that endrin have both 
criteria values.
3. Level of Protection
    Existing section 304(a) criteria are intended to protect a balanced 
and indigenous aquatic community by protecting most individuals within 
sensitive species. As a practical matter, the basic aquatic life 
procedure approximates the goal by deriving criteria to protect most 
individuals in the 95th percentile (most sensitive) of the tested 
genera. This is done by basing acute criteria on LC50 or similar tests, 
and dividing the final result by two to protect most individuals, as 
opposed to protecting only 50%. Less sensitive species are more fully 
protected, while more sensitive species are somewhat protected. There 
are exceptions procedures which override this basic approach where 
necessary to protect wildlife, plants, or commercially important 
aquatic species. See 50 FR 30784, July 29, 1985, for details. Tested 
species are selected to include a minimum data set of specified aquatic 
species. As such, tested species are considered to be surrogates for 
untested species. This same approach is currently proposed for benthic 
organisms via the sediment quality criteria. Comment is being sought on 
the appropriateness of this approach.
4. Use of SQC as ARAR's in the CERCLA Program
    The availability of sediment quality criteria for adoption by 
States into State water quality standards provides for the potential 
requirement in those States that the SQC be used as ARAR's. As 
discussed earlier, EPA is concerned that this ``mandatory clean-up 
level'' may be an inappropriate use of the proposed criteria. The 
Agency requests comment on the use of SQC as ARAR's should they be 
adopted into State water quality standards.
5. Definition of Sediments to Which Sediment Quality Criteria Apply
    The criteria documents define sediments to which SQC are applicable 
as those ``permanently inundated with water, intertidal sediment and to 
sediments inundated periodically for durations sufficient to permit 
development of benthic assemblages.'' The criteria are not intended to 
apply to ``sediments occasionally inundated so that they support 
terrestrial species.'' The Agency believes the appropriate uses of SQC 
are for those sediments that maintain, or have the potential to 
maintain if not contaminated, benthic aquatic assemblages. Comments 
that discuss a broader or narrower definition or that support the 
proposed definition are requested.

    Dated: December 28, 1993.
Robert Perciasepe,
Assistant Administrator for Water.
[FR Doc. 94-1133 Filed 1-14-94; 8:45 am]
BILLING CODE 6560-50-P