Chloramine Toxicity to the Amphipod Gammarus pseudolimnaeus and the Fathead Minnow (Pimephales promelas)

Abstract

The amphipod Gammarus pseudolimnaeus was subjected to 96-hr and 15-week exposures, and the fathead minnow (Pimephales promelas) to a 21-week exposure, to various chloramine concentrations under continuous-flow conditions. The most marked sublethal effects were reductions in the number of young produced by the amphipod and in egg production by the minnow. The 96-hr median tolerance limit for the amphipod was 220 μg/liter total chloramine. Fathead minnows in the long-term study were all killed at the highest concentration, 154 μg/liter total chloramine, within 3 days. The lowest measured total chloramine concentration in the long-term tests having no significant effect was < 3.4 μg/liter for the amphipod and 16.5 μg/liter for the fathead minnow.