CERIOFAST(TM) - AN ACUTE TOXICITY TEST BASED ON CERIODAPHNIA-DUBIA FEEDING-BEHAVIOR

We have developed a rapid acute toxicity test (CerioFASTTM) based on s uppression of feeding activity of Ceriodaphnia dubia in the presence o f toxicants. The bioassay consists of a 1-h exposure period to a given toxicant. Yeast cells, stained with a fluorescent dye, are added 20 m in before the end of the exposure period. Response to a toxic sample i s indicated by the absence of fluorescence in the gut of the daphnids. CerioFAST was compared to the standard 48-h C. dubia acute bioassay, using heavy metals and organic compounds. CerioFAST EC50s of Cd, Cu, P b, Ag, Zn, and carbofuran were in the 0.01-0.1-mg/L range, whereas EC5 0s of hexachloroethane, pentachlorophenol, trichlorophenol, and lindan e were in the 1-10-mg/L range. CerioFAST EC50s of the heavy metals and organics were well correlated with EC50s obtained with the 48-h C. du bia bioassay.