Ambient Water Quality Criteria for Ammonia, 1999 Update

摘要

This 1999 Update first presents an overview of ammonia toxicology in order to provide the background needed to explain the revisions of the freshwater ammonia criterion. Then the equations used in the older documents to address the temperature- and pHdependence of ammonia toxicity in fresh water are revised to take into account newer data, better models, and improved statistical methods. Next, a CMC (acute criterion) is derived from the acute toxicity data in the 1984/1985 criteria document, pH-normalized using the new equations. Then, new and old chronic toxicity data are evaluated and used to derive a CCC (chronic criterion). Lastly, the chronic averaging period is addressed.