金属製品製造工場のWET を用いた排水中毒性要因の推定とその改善例

抄録

Whole Effluent Toxicity (WET) testing evaluates the toxic effect of unknown or multiple substances in wastewater using aquatic organisms. It has already been implement in the US. When the result of WET testing indicates the effect exceeding a certain standard, Toxicity Reduction Evaluation (TRE) and Toxicity Identification Evaluation (TIE) are required for identifying the effluent characteristics causing toxicity and causing the toxicity.
In this study, we evaluated effluents from the metal manufacturing plant using three types of aquatic organisms (Danio rerio, Ceriodaphnia dubia, and Pseudokirchneriella subcapitata) with reference to the draft testing methods for effluent using bioassays. The result for one of effluents indicated toxic effect on C. dubia.
We conducted chelate resin absorption test and flocculation test as TRE/TIE. As a result, we identified Zn and Ni in the effluent as possible major toxicants and studied improvement of wastewater treatment for reducing toxicity.