Notice of Intent To Re-Evaluate the Aquatic Life Ambient Water Quality Criteria for Ammonia
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Fact Sheet; July 2004
EPA intends to re-evaluate the current aquatic life ambient water quality criteria for ammonia to determine whether they should be revised based on new toxicity data for aquatic organisms. The Agency also seeks additional pertinent toxicity data on the acute or chronic toxicity of ammonia to aquatic life and scientific views on the interpretation of data that may help us in re-evaluating the ammonia criteria.
- Ammonia Criteria Re-Evaluation and Request for Data and Information
- How to Get Additional Information
The Clean Water Act requires EPA publish and periodically update ambient water quality criteria to reflect the latest scientific knowledge on the effects of water pollutants on public health and welfare, aquatic life, and recreation. EPA published "Ambient Water Quality Criteria for Ammonia - 1984." Since that time, results of additional toxicity tests on ammonia have been published that could affect the freshwater criterion for ammonia. The Agency published a 1998 Update to revise the 1984/1985 ammonia criteria document by addressing important issues to the extent possible in a short-term effort without additional research. EPA obtained public comment on the 1998 Update. In response to those comments EPA modified its criteria recommendations and prepared an 1999 Update. The 1999 Update differed from the 1998 Update primarily in the handling of the temperature-dependency for the chronic criterion (criterion continuous concentration or CCC) and, therefore, the formulation of the CCC and the expression of this national criterion.
Ammonia Criteria Re-Evaluation and Request for Data and Information
EPA notified the public in the Federal Register of its intent to re-evaluate, based on new toxicity data on aquatic organisms, the current aquatic life criteria for ammonia to determine if they should be revised. In particular, recent studies on freshwater mussels suggest that some freshwater mussel species may be more sensitive to ammonia exposure than the aquatic organisms considered in deriving the current ammonia criteria.
EPA recently completed a comprehensive review of the available toxicity data for ammonia and now seeks additional pertinent toxicity data or information. In particular, EPA is interested in new data on the acute or chronic toxicity of ammonia to aquatic life and scientific views on how to interpret the data, specifically new data on the toxicity of ammonia to freshwater mussels. Persons wishing to submit data should assure that it is adequately documented and contains supporting information indicating that acceptable test procedures were used.
How to Get Additional Information
U.S. Environmental Protection Agency
Office of Water, Health and Ecological Criteria Division (4304T)
1200 Pennsylvania Avenue, NW
Washington, DC 20004