COMPARATIVE ACUTE TOXICITY OF THE FIRST 50 MULTICENTER EVALUATION OF IN-VITRO CYTOTOXICITY CHEMICALS TO AQUATIC NON-VERTEBRATES

The acute toxicity data of the first 50 chemicals of the Multicentre E valuation of In Vitro Cytotoxicity (MEIC) programme is compared for th ree ''cyst-based toxicity tests'' (Artoxkit M with Artemia salina, Str eptoxkit F with Streptocephalus proboscideus, and Rotoxkit F with Brac hionus calyciflorus), and two other tests (the Daphnia magna and the P hotobacterium phosphoreum Microtox(TM) tests) commonly used in ecotoxi cology. The difference in sensitivity for the 50 chemicals was as high as 19 orders of magnitude (on a molecular weight basis) between the m ost and least sensitive species. Generally, a similar toxicity ranking of the 5 test species was found for most of the chemicals and the int erspecies correlations were high. Results from principal Component Ana lysis (PCA) and cluster analysis indicated that the groupings are not related to a clear and defined chemical structure. However, the loadin g plot of the first two principal components may aid in selecting the minimum number and type of tests that have to be included in a battery which encompasses a broad spectrum of toxicity levels. Consequently, this study supports the use of a selected battery of tests to evaluate ecotoxicity and suggests its possible importance for screening of bio logically-active compounds from natural sources.