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Water Quality Criteria; Ambient Water Quality Criteria

Note: EPA no longer updates this information, but it may be useful as a reference or resource.

 [Federal Register: August 7, 1997 (Volume 62, Number 152)]
[Notices]
[Page 42554]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr07au97-81]

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ENVIRONMENTAL PROTECTION AGENCY

[OW-FRL-5872-5]


Water Quality Criteria; Ambient Water Quality Criteria

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of Ambient Water Quality Criteria Document for
Tributyltin (TBT) and Request for Comments.

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SUMMARY: The Environmental Protection Agency (EPA) announces the
availability for public comment of an ambient water quality criteria
document for tributyltin (TBT). This document contains ambient water
quality criteria for the protection of aquatic organisms and their
uses. These criteria are guidance to States and others, and in
themselves have no binding legal effect. When published in final form,
these criteria may form the basis for enforceable State water quality
standards. These TBT criteria are published pursuant to Section
304(a)(1) of the Clean Water Act.

DATES: Written comments should be submitted to the person listed
directly below by October 6, 1997.

ADDRESSES: This notice contains a summary of the criteria document for
tributyltin (TBT). Copies of the complete document may be obtained
from: U.S. Environmental Protection Agency , National Center for
Environmental Publications and Information, 11029 Kenwood Road,
Cincinnati, Ohio 45242, phone (513) 489-8190 fax (513) 489-8695.

FOR FUTHER INFORMATION CONTACT: Comments should be sent to: Dr. Frank
Gostomski, Health and Ecological Criteria Division (4304), Office of
Science and Technology, Office of Water, U.S. Environmental Protection
Agency, 401 M Street SW, Washington, DC 20460.

SUPPLEMENTARY INFORMATION:

Background

    Section 304 (a) (1) of the Clean Water Act [33 U.S.C. 1314 (a) (1)]
requires EPA to publish and periodically update ambient water quality
criteria. These criteria are to reflect the latest scientific knowledge
on the identifiable effects of pollutants on public health and welfare,
aquatic life and recreation. When published in final form, EPA water
quality criteria may form the basis for enforceable State water quality
standards.

Criteria Document

    EPA previously issued an ambient water quality criteria document
for TBT for public comment on June 1, 1989 [54 FR 23529]. EPA also
issued a notice of availability of additional toxicity data for TBT on
October 25, 1989 [54 FR 43482]. Today's ambient water quality criteria
document for TBT was developed by EPA after consideration of public
comment on the 1989 draft criteria and an updated literature search
that EPA conducted in January, 1997. EPA intends to issue a final TBT
ambient water quality criteria document after consideration of public
comment.

    Dated: August 1, 1997.
Robert Perciasepe,
Assistant Administrator for Water.

Appendix A--Summary of Ambient Water Quality Criteria for TBT

Freshwater Aquatic Life

    The procedures described in the ``Guidelines for Deriving
Numerical National Water Quality Criteria for the Protection of
Aquatic Organisms and Their Uses'' indicate that, except possibly
where a locally important species is very sensitive, freshwater
aquatic life and their uses should not be affected unacceptably if
the four-day average concentration of tributyltin does not exceed
0.063 greek-m g/L more than once every three years on the average
and if the one-hour average concentration does not exceed 0.46
greek-m g/L more than once every three years on the average.

Saltwater Aquatic Life

    The procedures described in the ``Guidelines for Deriving
Numerical National Water Quality Criteria for the Protection of
Aquatic Organisms and Their Uses'' indicate that, except where a
locally important species is very sensitive, saltwater organisms and
their uses should not be affected unacceptably if the four-day
average concentration of tributyltin does not exceed 0.010
greek-m g/L more than once every three years on the average and if
the one-hour average concentration does not exceed 0.37 greek-m g/L
more than once every three years on the average.

Implementation

    As discussed in the Water Quality Standards Regulation (40 CFR
Part 131; 48 FR 51400), a water quality criterion for aquatic life
has regulatory effect only after it has been adopted in State water
quality standards. Such a criterion for a pollutant is to be set at
a level protective of a particular designated use. With the approval
of EPA, States designate one or more uses for each body of water or
segment thereof and adopt criteria that are protective of the
use[s]. In each standard, a State may adopt the national recommended
criterion, if one exists, or if adequately justified, a site-
specific criterion. Site-specific criteria may include not only
site-specific criterion concentrations, but also site-specific, and
possibly pollutant-specific, durations of averaging periods and
frequencies of allowed excursions. The averaging periods of ``one
hour'' and ``four days'' were selected by EPA on the basis of data
concerning how rapidly some aquatic species react to increases in
the concentrations of some pollutants.
    It is EPA's best scientific judgment that aquatic ecosystems
should not be exposed to contaminants in excess of the criterion
more often than once every three years. However, various species and
ecosystems react and recover at greatly differing rates. Therefore,
if adequate justification is provided, site-specific and/or
pollutant-specific concentrations, durations, and frequencies may be
higher or lower than those given in national water quality criteria
for aquatic life. Use of criteria, which have been adopted in state
water quality standards, for developing water quality-based permit
limits and for designing waste treatment facilities requires
selection of an appropriate wasteload allocation model. Although
dynamic models are preferred for the application of these criteria,
limited data or other considerations might require the use of a
steady-state model. Guidance on mixing zones and the design of
monitoring programs is also available through EPA.

[FR Doc. 97-20975 Filed 8-6-97; 8:45 am]
BILLING CODE 6560-50-P

 
 

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