[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

[[Page 52193]]

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
------------------------------------------------------------------------
 
------------------------------------------------------------------------
                  (Magnitude, Frequency, and Duration)
------------------------------------------------------------------------
                               (mg TAN/L)
                           pH 7.0, T=20 [deg]C
------------------------------------------------------------------------
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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