United States
Environmental Protection
Agency
Environmental Research
Laboratory
Duluth MN 55804
Research and Development
EPA-600/S3-84-099 Dec. 1984
4>EPA Project Summary
Guidelines for Deriving
Numerical Aquatic Site-Specific
Water Quality Criteria by
Modifying National Criteria
Anthony R. Carlson, William A. Brungs, Gary A. Chapman, and
David J. Hansen
A major goal of the U.S. Environ-
mental Protection Agency is to directly
link regulatory decision-making
regarding priority water bodies to the
capacity of those water bodies to
receive wastewater discharges and still
maintain acceptable water quality. To
assist states in achieving this goal in a
consistent, cost-effective manner, the
Office of Research and Development
(ORD) has developed a new approach
to water quality criteria derivation fully
described in the final report "Guidelines
for Deriving Numerical Aquatic Site-
Specific Water Quality Criteria by
Modifying National Criteria."
These guidelines provide a series of
protocols for modifying national water
quality criteria to reflect local
environmental conditions. The national
criteria serve as benchmarks to protect
the biological integrity of all water
bodies and may require adjustments for
site-specific applications. The new
protocols take into account site-
specific variations in species composi-
tion, physical factors, and chemical
water quality variables. Consideration
of local conditions assures that criteria
for a given water body are tailored spe-
cifically to its aquatic life and uses.
This Project Summary was developed
by EPA's Environmental Research Lab-
oratories: Duluth. MN; Narragansett,
Rl; Corvallis, OR; Gulf Breeze, FL, to
announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Technical Discussion
Section 304 of the Clean Water Act
directs EPA to publish and periodically
review water quality criteria for the
protection of public health and welfare,
aquatic life, and recreation. The water
quality criteria incorporate data on
aquatic plants and animals which occupy
various trophic levels, in addition to
applying current scientific judgments
relating pollutant concentrations to
environmental and health effects. These
water quality criteria are then used by the
states to formulate ambient water quality
standards.
States can use site-specific and
national criteria to develop enforceable
numbers such as water quality
standards, mixing zone guidance, or
water quality-based effluent limits. The
development of such standards or limits
takes into account additional factors such
as the water body usage at the site,
environmental and analytical character-
istics of chemical pollutants, accuracy of
extrapolation from laboratory data to field
situations, and the relationship between
the species for which data are available
and the body of water which is to be
protected.
Implementation of criteria modification
process requires site selection, data col-
lection and evaluation, biological and
water quality sampling and toxicity test-
ing, and ultimately, generation of site
water quality criteria.
There are three procedures in the ORU
Guidelines for modifying national criteria
to develop site-specific criteria.
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• A recalculation procedure to account
for differences in selected resident
species sensitivity to a chemical. This
procedure is the least labor intensive
and the least costly, since it may
require no additional toxicity tests.
• An indicator (resident or non-resi-
dent) species procedure to account
for differences in the biological avail-
ability and/or toxicity of a pollutant
that is affected by the physical condi-
tions and chemical characteristics of
the receiving water.
• A resident species procedure to
account for differences in both
species sensitivity and ambient
water quality This procedure is the
most resource intensive and,
therefore, the most costly since it
may require a large number of acute
and chronic toxicity tests with
resident species in site water.
To perform these procedures, the ORD
final report provides a recommended list
of state-of-the-art methods for toxicity
tests with aquatic organisms, which
include fishes, invertebrates, and plants.
The authors are with EPA's Environmental Research Laboratories at the locations
noted: A. R. Carlson , Duluth. MN 55804; W. A. Brungs, Narragansett, Rl
02882; G. A. Chapman, Corvallis, OR 97333; and D. J. Hansen,
Narragansett, Rl 02882 /formerly Gulf Breeze, FL 32561).
The complete report, entitled "Guidelines for Deriving Numerical Aquatic Site-
Specific Water Quality Criteria by Modifying National Criteria," (Order No. PB
85-121 101; Cost: $8.50, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield. VA 22161
Telephone: 703-487-4650
The EPA authors can be contacted at his respective laboratory:
Environmental Research Laboratory
U.S. Environmental Protection Agency
Duluth, MN 55804
(city and state indicated above)
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