PATTERN-ANALYSIS OF THE VARIATION IN THE SENSITIVITY OF AQUATIC SPECIES TO TOXICANTS

Our aim in this study was to identify groups of species showing a simi lar pattern in their sensitivity to toxicants and to relate the patter ns to the mode of toxic action and biological species characteristics. A data matrix was composed of acute toxicity data for 26 aquatic spec ies and 21 compounds. Most of the variation in the toxicological data was due to differences in toxicity of compounds and not intrinsic diff erences between species, so that practically every species can be used to order compounds with respect to average toxicity. Compounds with h igh overall toxicity also had large interspecies variation in sensitiv ity. The toxicity of non-polar narcotics correlated well with the log K-ow. Compounds with a specific or reactive mode of action were more t han a factor 10 toxic than predicted by their log K-ow. Patterns in sp ecies sensitivity were more diffuse because only part of the variance in species sensitivity could be explained. Fishes and amphibians were more sensitive to dieldrin, lindane and pentachlorophenol than were in vertebrates. Among the arthropods, the Phyllopoda (daphnids) were the most sensitive species. They were very sensitive to aniline, the heavy metals, malathion and parathion. (C) 1997 Elsevier Science Ltd.