Development of Water Quality Criteria for Ammonia and Total Residual Chlorine for the Protection of Aquatic Life in Two Johnson County, Kansas, Streams

Abstract

A study was conducted to determine water quality criteria for ammonia and total residual chlorine (TRC) for the protection of aquatic life in two streams in Johnson County, Kan. The test streams selected were Mill and Cedar Creeks. The parallel streams flow into the Kansas River and share similar watershed characteristics. However, unlike Mill Creek, Cedar Creek does not receive sewage treatment plant effluents. Species indigenous to the streams were collected, and 96-h acute toxicity tests were conducted with ammonia and TRC. Following the laboratory work, a test was conducted in Cedar Creek whereby ammonia was introduced for 24-h. Test organisms were placed in cages in the stream, and mortalities were observed throughout the test period. Based on this research and other existing evidence, the conclusion was reached that if un-ionized ammonia concentrations in the two streams do not exceed 0.07 mg/litre un-ionized ammonia expressed as nitrogen (NH3-N) as a 24-h average, or 0.4 mg/litre NH3-N at any time, aquatic life in the two streams will suffer no adverse effects. Nor will these organisms be adversely affected by total residual chlorine concentrations that do not exceed 0.02 mg/litre TRC as a 24-h average, or 0.03 mg/litre TRC at any time.