Abstract
Toxic level of chemical contamination in the river waters in Tokyo was bioassayed using Microtox test, Ames Salmonella mutation test, Daphnia immobilization test and algal growth inhibition test over a period of 3 years. Though no serious toxicity was found, 60% of river water samples reached positive response level of toxicity. The Microtox test and the Ames test are useful to assess the total acute/geno-toxicity level of river water. The Daphnia immobilization test and the algal growth inhibition test indicate whether the chemical contamination in river water reaches toxic level for crustaceans and algae, respectively. And adaptation of river water to the guideline value is evaluated using both bioassays without chemical analysis. The combination of these bioassays, which have individual specific detection spectrum, is effective for the assessment and evaluation of chemical contaminants.
