[Federal Register Volume 78, Number 163 (Thursday, August 22, 2013)]
[Notices]
[Pages 52192-52194]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-20307]
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ENVIRONMENTAL PROTECTION AGENCY
[EPA-HQ-OW-2009-0921; FRL-9810-4]
Final Aquatic Life Ambient Water Quality Criteria For Ammonia--
Freshwater 2013
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of availability of final criteria.
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SUMMARY: Pursuant to section 304(a) of the Clean Water Act (CWA), the
Environmental Protection Agency (EPA) is announcing the availability of
final national recommended ambient water quality criteria for the
protection of aquatic life from effects of ammonia in freshwater (EPA
822-R-13-001). The final criteria incorporate the latest scientific
knowledge on the toxicity of ammonia to freshwater aquatic life. On
December 30, 2009, EPA published draft national recommended water
quality criteria for ammonia and provided the public an opportunity to
provide scientific views. Aquatic life criteria are developed based on
EPA's Guidelines for Deriving Numerical National Water Quality Criteria
for the Protection of Aquatic Organisms and Their Uses (1985), (EPA/R-
85-100). EPA's recommended section 304(a) water quality criteria
provide guidance to States and authorized Tribes in adopting water
quality standards for protecting aquatic life and human health. EPA's
recommended water quality criteria by themselves have no binding legal
effect. These national recommended criteria for ammonia in freshwater
are intended to protect aquatic life and do not address human health
toxicity data. The water quality criteria for ammonia for the
protection of saltwater organisms are not being updated at this time.
EPA's national recommended final acute ambient water quality criteria
(AWQC) for protecting freshwater organisms from potential effects of
ammonia is 17 mg/L total ammonia nitrogen (TAN) and the final chronic
AWQC for ammonia is 1.9 mg/L TAN at pH 7.0 and temperature 20 [deg]C.
ADDRESSES: Scientific views received from the public on the draft
ammonia criteria documents are available from the EPA Docket Center and
are identified by Docket ID No. EPA-HQ-OW-2009-0921. They may be
accessed online at:
www.regulations.gov: Follow the on-line instructions.
Email: [email protected].
Mail: US Environmental Protection Agency; EPA Docket
Center (EPA/DC) Water Docket, MC 2822T; 1200 Pennsylvania Avenue NW.,
Washington, DC 20460.
On Site: EPA Docket Center, 1301 Constitution Ave. NW.,
EPA West, Room 3334, Washington, DC. This Docket Facility is open from
8:30 a.m. until 4:30 p.m., EST, Monday through Friday, excluding legal
holidays. The telephone number for the Public Reading Room is (202)
566-1744, and the telephone number for the Office of Water is (202)
566-2426.
For additional information about EPA's public docket visit the EPA
Docket Center homepage at http://www.epa.gov/epahome/dockets.htm.
FOR FURTHER INFORMATION CONTACT: Lisa Huff, Health and Ecological
Criteria Division (4304T), U.S. EPA, 1200 Pennsylvania Ave. NW.,
Washington, DC 20460; (202) 566-0787; [email protected].
SUPPLEMENTARY INFORMATION:
I. What are water quality criteria?
Water quality criteria are either narrative descriptions of water
quality or scientifically derived numeric values that protect aquatic
life or human health from the deleterious effects of pollutants in
ambient water.
Section 304(a)(1) of the Clean Water Act (CWA) requires EPA to
develop and publish and, from time to time, revise, criteria for
protection of water quality and human health that accurately reflect
the latest scientific knowledge. Water quality criteria developed under
section 304(a) are based solely on data and scientific judgments on the
relationship between pollutant concentrations and environmental and
human health effects. Section 304(a) criteria do not reflect
consideration of economic impacts or the technological feasibility of
meeting pollutant concentrations in ambient water.
Section 304(a) criteria provide guidance to States and authorized
Tribes in adopting water quality standards that ultimately provide a
basis for assessing water body health and controlling discharges or
releases of pollutants. Under the CWA and its implementing regulations,
States and authorized Tribes are to adopt water quality criteria to
protect designated uses (e.g., public water supply, aquatic life,
recreational use, or industrial use). EPA's recommended water quality
criteria do not substitute for the CWA or regulations, nor are they
regulations themselves. Thus, EPA's recommended criteria do not impose
legally binding requirements. States and authorized Tribes have the
discretion to adopt, where appropriate, other scientifically defensible
water quality criteria that differ from these recommendations.
II. What is ammonia and why is EPA concerned about it?
Ammonia is a constituent of nitrogen pollution. Unlike other forms
of nitrogen, which can cause eutrophication of a water body at elevated
concentrations, the primary concern with ammonia is its direct toxic
effects on aquatic life, which are exacerbated by elevated pH and
temperature. Ammonia is considered one of the most important pollutants
in the aquatic environment not only because of its highly toxic nature
and occurrence in surface water systems, but also because many
effluents have to be treated in order to keep the concentrations of
ammonia in surface waters from being unacceptably high. Ammonia can
enter the aquatic environment via direct means such as municipal
effluent discharges and the excretion of nitrogenous wastes from
animals, and indirect means such as nitrogen fixation, air deposition,
and runoff from agricultural lands.
III. What are the 2013 ammonia criteria recommendations?
EPA is today publishing final national recommended ambient water
quality criteria for protecting freshwater aquatic life for ammonia.
These final criteria updates are based on EPA's Guidelines for Deriving
Numerical National Water Quality Criteria for the Protection of Aquatic
Organisms and Their Uses (1985), (EPA/R-85-100). These Guidelines
describe the Agency's current approach for deriving national
recommended water quality criteria to protect aquatic life. The latest
toxicity data and other information on the effects of ammonia on
freshwater aquatic life were obtained from reliable sources and
subjected to both internal and external scientific peer review. The
national recommended water quality criteria for ammonia in saltwater
are not being updated at this time.
The available data for ammonia, evaluated in accordance with EPA's
Guidelines for Deriving Numerical National Water Quality Criteria for
the Protection of Aquatic Organisms and Their Uses (1985), indicate
that freshwater aquatic animals would have
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an appropriate level of protection if the following are attained:
Freshwater: Freshwater aquatic organisms and their uses should not
be affected unacceptably if--
1. The one-hour average concentration of total ammonia nitrogen (in
mg TAN/L) does not exceed, more than once every three years on the
average, the criterion maximum concentration (i.e., the ``CMC,'' or
``acute criterion'').
2A. The thirty-day average concentration of total ammonia nitrogen
(in mg TAN/L) does not exceed, more than once every three years on the
average, the criterion continuous concentration (i.e., the ``CCC,'' or
``chronic criterion'').
2B. In addition, the highest four-day average within the 30-day
period should not exceed 2.5 times the CCC, more than once every three
years on the average.
The acute and chronic criteria concentrations are expressed as
functions of temperature and pH, such that values differ across sites,
and differ over time within a site. The criteria document describes the
relationship between ammonia and these water quality factors and
provides tables showing how the criteria value changes with varying pH
and temperatures. As temperature decreases, freshwater invertebrates,
but not fish, become less sensitive to ammonia, and below a particular
temperature threshold (i.e., 15.7 [deg]C for the CMC and 7 [deg]C for
the CCC), fish become more sensitive than invertebrates.
Acute Criteria: At pH 7, the CMC ranges from 7.3 mg TAN/L at 30
[deg]C to 24 mg TAN/L at 0 [deg]C.
Chronic Criteria: At pH 7, the CCC ranges from 0.99 mg TAN/L at 30
[deg]C to 4.4 mg TAN/L at 0 [deg]C.
2013 Final ALC Criteria for Ammonia
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(Magnitude, Frequency, and Duration)
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(mg TAN/L)
pH 7.0, T=20 [deg]C
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Acute (1-hour average)........................................ 17
Chronic (30-day rolling average).............................. *1.9
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* Not to exceed 2.5 times the CCC as a 4-day average within the 30-days,
i.e. 4.8 mg TAN/L at pH 7 and 20 [deg]C more than once in 3 years on
average.
Criteria frequency: Not to be exceeded more than once in 3 years on
average.
Note: These criteria values are appropriate at the standard
normalized pH and temperature of pH 7.0, a temperature of 20 [deg]C;
ammonia criteria are a function pH and temperature.
IV. What new data have been included in the 2013 ammonia criteria
recommendations?
Since the publication of the 1999 Update of Ambient Water Quality
Criteria for Ammonia (EPA-822-R-99-014), numerous new scientific
studies were published indicating that freshwater mussels are more
sensitive to ammonia than the organisms represented in the 1999
criteria dataset, and that snails, another freshwater mollusk group,
are also sensitive to ammonia. EPA evaluated the new toxicity data per
EPA's 1985 Guidelines for deriving aquatic life criteria (Stephan et
al., 1985) and incorporated the acceptable data in calculating the
final criteria for ammonia. The final recommended acute and chronic
criteria for ammonia presented in this document are protective of the
aquatic community, including freshwater mollusks.
V. What is the relationship between the ammonia criteria
recommendations and state or tribal water quality criteria?
Water quality standards consist of three principal elements:
Designated uses, water quality criteria to protect those uses, and
antidegradation requirements, providing for protection of existing
water uses and limitations on degradation of high quality waters. As
part of the water quality standards triennial review process defined in
Section 303(c)(1) of the CWA, the States and authorized Tribes are
responsible for developing, maintaining and revising water quality
standards. Section 303(c)(1) requires States and authorized Tribes to
review and modify, if appropriate, their water quality standards at
least once every three years.
States and authorized Tribes must adopt water quality criteria into
their water quality standards that protect designated uses. States may
develop their criteria based on EPA's recommended section 304(a) water
quality criteria or other scientifically defensible methods. A state's
criteria must contain sufficient parameters or constituents to protect
the designated uses. Consistent with 40 CFR 131.21, new or revised
water quality criteria adopted into law by States and authorized Tribes
on or after May 30, 2000 are in effect for CWA purposes only after EPA
approval.
States and authorized Tribes may also develop site-specific
criteria for particular waterbodies as appropriate, following EPA
procedures described in the Guidelines for Deriving Numerical Aquatic
Site-Specific Water Quality Criteria by Modifying National Criteria
(USEPA, 1984f). A site-specific criterion is intended to come closer
than the national criterion to providing the intended level of
protection to the aquatic life at that particular site, usually by
taking into account the biological and/or chemical conditions (i.e.,
the species composition and/or water quality characteristics) at that
site. If data in the national criterion document and/or from other
sources indicated that the site's resident species range of sensitivity
is different from that for the species in the national criterion
document, States and authorized Tribes can develop site-specific
criteria following the Revised Deletion Process for the Site-Specific
Recalculation Procedure for Aquatic Life Criteria (EPA 823-R-13-001).
For example, if freshwater mussel species are not resident at a site,
the Revised Deletion Process for the Site-Specific Recalculation
Procedure for Aquatic Life Criteria might be used to recalculate the
criteria without these species.
VI. Where can I find more information about water quality criteria and
water quality standards?
The EPA has developed supporting documents to aid states
considering adoption of the 2013 recommended ammonia criteria.
Flexibilities for States Applying EPA's Ammonia Criteria
Recommendations (EPA 800-F-13-001) provides an overview of a number of
flexibilities available for state consideration, including the Revised
Deletion Process for the Site-Specific Recalculation Procedure for
Aquatic Life Criteria mentioned above, variances, revisions to
designated uses, dilution allowances, and compliance schedules. The
document describes how each of these flexibilities fits within a
state's water quality standards adoption and implementation process.
For more information about water quality criteria and water quality
standards refer to the following: Water Quality Standards Handbook (EPA
823-B94-005a); Advanced Notice of Proposed Rule Making (ANPRM),
(63FR36742); Water Quality Criteria and Standards Plan--Priorities for
the Future (EPA 822-R-98-003); Guidelines and Methodologies Used in the
Preparation of Health Effects Assessment Chapters of the Consent Decree
Water Criteria Documents (45FR79347); Methodology for Deriving Ambient
Water Quality Criteria for the Protection of Human Health (2000), EPA-
822-B-00-004); Guidelines for Deriving Numerical National Water Quality
Criteria for the Protection of
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Aquatic Organisms and Their Uses (EPA 822/R-85-100); National Strategy
for the Development of Regional Nutrient Criteria (EPA 822-R-98-002);
and EPA Review and Approval of State and Tribal Water Quality Standards
(65FR24641).
You can find these publications through EPA's National Service
Center for Environmental Publications (NSCEP, previously NCEPI) or on
the Office of Science and Technology's Home-page (http://www.epa.gov/waterscience).
Dated: April 30, 2013.
Nancy K. Stoner,
Acting Assistant Administrator, Office of Water.
[FR Doc. 2013-20307 Filed 8-21-13; 8:45 am]
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