Eight industrial effluents from Toyama Prefecture, Japan were subjected to three freshwater short-term chronic assays to analyze the potential of ecotoxic impact on receiving water. Tests comprised algal inhibition (Pseudokirchneriella subcapitata), crustacean reproduction (Ceriodaphnia dubia), fish embryo-larva (Danio rerio). Among the eight effluents, chronic toxic effects on alga, crustacea and fish were observed in six, six and one effluents respectively. No-observed-effect concentrations (NOECs) equal to or less than 5% were found in five samples. Nickel and salts were suspected as the causative factors from comparing water parameters with their effects. The impact of these effluents after discharged into receiving water is discussed. The results of the study show the effectiveness of the whole effluent toxicity approach to compensate the present shortcoming of wastewater regulation in Japan.
