E9-30992. Draft 2009 Update Aquatic Life Ambient Water Quality Criteria for Ammonia-Freshwater

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Notice of availability of draft criteria and request for scientific views.

SUMMARY:

Pursuant to section 304(a) of the Clean Water Act (CWA), the Environmental Protection Agency (EPA) is announcing the availability of draft national recommended water quality criteria for ammonia for the protection of aquatic life. The draft criteria 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). 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 and provide guidance to EPA for promulgating Federal regulations under CWA section 303(c), when such action is necessary.

DATES:

Scientific views must be received on or before March 1, 2010. Comments postmarked after this date may not be considered.

ADDRESSES:

Submit your scientific views, identified by Docket ID No. EPA-HQ-OW-2009- 0921, by one of the following methods:

• http://www.regulations.gov: Follow the on-line instructions for submitting comments.
• E-mail: [e-mail].
• Mail: U.S. Environmental Protection Agency; EPA Docket Center (EPA/DC) Water Docket, MC 28221T; 1200 Pennsylvania Avenue, NW., Washington, DC 20460.
• Hand Delivery: EPA Docket Center, 1301 Constitution Ave, NW., EPA West, Room 3334, Washington DC. Such deliveries are only accepted during the Docket's normal hours of operation, and special arrangements should be made for deliveries of boxed information.

Instructions: Direct your comments to Docket ID No. EPA-HQ-OW-2009-0921. EPA's policy is that all comments received will be included in the public docket without change and may be made available online at http://www.regulations.gov,, including any personal information provided, unless the comment includes information claimed to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through http://www.regulations.gov or e-mail. The http://www.regulations.gov Web site is an “anonymous access” system, which means EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an e-mail comment directly to EPA without going through http://www.regulations.gov your e-mail address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects or viruses. For additional information about EPA's public docket visit the EPA Docket Center homepage at http://www.epa.gov/​epahome/​dockets.htm.

Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some information is not publicly available, e.g., CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, will be publicly available only in hard copy. Publicly available docket materials are available either electronically in http://www.regulations.gov or in hard copy at the Office of Water Docket/EPA/DC, 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 [phone], and the telephone number for the Office of Water Docket is [phone].

FOR FURTHER INFORMATION CONTACT:

Lisa Huff, Health and Ecological Criteria Division (4304T), U.S. EPA, 1200 Pennsylvania Ave., NW., Washington, DC 20460; [phone]; [e-mail].

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 requires EPA to develop and publish and, from time to time, revise, criteria for water quality accurately reflecting 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 controlling discharges or releases of pollutants. The criteria also provide guidance to EPA when promulgating Federal regulations under section 303(c) when such action is necessary. 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 Are the Ammonia Criteria?

EPA is today publishing draft national recommended water quality criteria (NRWQC) for ammonia for protecting aquatic life. These draft 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. Toxicity data and other information on the effects of ammonia were obtained from reliable sources and subjected to both internal and external scientific peer review. The NRWQC for ammonia saltwater are not being updated at this time.

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 N/L) does not exceed, more than once every three years on the average, the CMC (acute criterion), which is dependent on the aquatic organisms present.

2A. The thirty-day average concentration of total ammonia nitrogen (in mg N/L) does not exceed, more than once every three years on the average, the CCC (chronic criterion), which is dependent on the aquatic organisms present.

2B. In addition, the highest four-day average within the 30-day period should not exceed 2.5 times the CCC.

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. See draft criteria document (pp. 34-38) for actual equations describing this function. As temperature decreases, invertebrates, but not fish, become less sensitive to ammonia, and below a particular temperature threshold, fish become the most sensitive genera.

Acute Criteria: At pH=8, where freshwater mussels are present, the criterion concentration ranges from 1.90 mg N/L at 30° C to 9.81 mg N/L at 0° C. At pH=8, where freshwater mussels are absent the criterion concentration ranges from 3.29 mg N/L at 30° C to 9.99 mg N/L at 0° C.

Chronic Criteria: At pH=8, where freshwater mussels are present, irrespective of whether fish early life stages (ELS) are present or absent, the criterion ranges from 0.186 mg N/L at 30° C to 0.817 mg N/L at 0° C. When freshwater mussels are absent, the values range from 1.33 mg N/L at 30° C to 2.32 mg N/L at 0° C at times when fish ELS are present, and from 1.33 mg N/L at 30° C to 5.87 mg N/L at 0° C at times when fish ELS are absent.

	Draft 2009 ammonia criteria (at pH 8 and 25° C)	Current 1999 criteria (at pH 8 and 25° C)
Acute	2.9 mg N/L mussels present	5.6 mg N/L salmon present.
	5.0 mg N/L mussels absent
Chronic	0.26 mg N/L mussels present	1.2 mg N/L fish early life stages present.
	1.8 mg N/L mussels absent

Note:

These criteria values are appropriate at the standard normalized pH and temperature; the criteria values are a function of the variability of pH and temperature.

The water quality criteria for ammonia saltwater are not being updated at this time.

III. What is the Relationship Between the Water Quality Criteria and State or Tribal Water Quality Standards?

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 maintaining and revising water quality standards. 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. 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 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.

IV. Where Can I Find More Information About Water Quality Criteria and Water Quality Standards?

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 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: December 23, 2009.

Peter S. Silva,

Assistant Administrator for Water.