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Ammonia Aquatic Life Criteria
Re-Evaluation
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On July 8th, 2004, we notified the public in the Federal Register (69 FR 41262) of our intent to re-evaluate the current aquatic life criteria for ammonia in response to recent studies suggesting that some freshwater mussel species may be more sensitive to ammonia exposure than the aquatic organisms considered in deriving the current ammonia criteria.
As part of the Federal Register notice, EPA requested additional pertinent data on the acute or chronic toxicity of ammonia to aquatic life, particularly freshwater mussels, and scientific views on the use of mussel data that may help EPA in re-evaluating the ammonia criteria. To date, EPA has not made any final decisions on what to do about the ammonia criteria, and will not do so until all issues, questions and new scientific information is explored.
Mussel Toxicity Testing Workshop
In August of 2005, in Chicago, Illinois, we convened a workshop to provide a forum for information exchange on science issues related to freshwater mussels toxicity testing, including those raised in response to the Federal Register notice. At the workshop, EPA and those in attendance shared information, data, studies and the latest research findings relevant to mussel toxicity testing. Attendees had the opportunity to comment on this information, ask questions, and otherwise participate in the information exchange.
This workshop was not an EPA decision-making meeting nor a public hearing.
- Workshop Proceedings Summary Report (PDF) (24 pp., 70 K)
- Abstracts (PDF) (15 pp., 62 K)
- Presentations
Note: Mussel Toxicity Testing Workshop presentations represent the work of individual researchers and the results presented in these proceedings do not necessarily reflect an EPA endorsement of the findings.
Notice of Intent to Re-evaluate and Request for Data and Information
On July 8th, 2004, we notified the public of our intent to re-evaluate the current aquatic life criteria for ammonia to determine if a revision is warranted based on new toxicity data for aquatic organisms. We also solicited any additional pertinent toxicity data or information that may be useful in re-evaluating these criteria.
- Fact Sheet
- Federal Register Notice (July 8, 2004)
- List of new ammonia references (PDF) (98 K, 13 pp.)
1999 Ammonia Criteria Update
We published a 1999 Update of Ambient Water Quality Criteria for Ammonia (1999 Ammonia Update; EPA 822-R-99-014). The 1999 Ammonia Update contains EPA's most recent freshwater aquatic life criteria for ammonia, superseding all previous EPA recommended freshwater criteria for ammonia. The 1999 Ammonia Update pertains only to fresh waters. It does not change or supersede the EPA's aquatic life criterion for ammonia in salf water, published in Ambient Water Quality Criteria for Ammonia (Saltwater) in 1989.
- Fact Sheet (December 1999)
- Technical Fact Sheet
- Federal Register Notice (Text only, some tables omitted) | Federal Register Notice (PDF) (8 pp., 160 K; Print format that contains all tables) (December 22, 1999)
- 1999 Ammonia Update (PDF) (153 pp., 790 K; EPA 822-R-99-014)