Sensitivity of characteristic riverine insects, the caddisfly Cyrnustrimaculatus and the mayfly Ephoron virgo, to copper and diazinon

This study reports the effects of two model toxicants, copper and diazinon, on two characteristic riverine insect species, the caddisfly Cyrnus trimaculatus and the mayfly Ephoron virgo. It was demonstratedthat these species are very sensitive to both compounds in comparison with aquatic insects traditionally used in ecotoxicity tests. For diazinon, the 96-h LC₅₀ value of Cyrnus trimaculatus (1.1 Mu g/l) is lower than for any other insect species known from the literature and for copper it was demonstrated that Ephoron virgo is amongthe most sensitive aquatic insect species. The observed low LC₅₀ values stress the importance of using these indigenous species in assessing the risk of environmental contaminants in large European rivers and in defining conditions for ecological recovery. [ABSTRACT FROM AUTHOR]