Abstract
Various chemical substances are used in our industrial, agricultural, and daily activities, and are continuously discharged into the aquatic environment. Since the mixture effects of these compounds have become growing concerns, direct measurement of adverse effects of effluents or ambient waters on aquatic organisms has been frequently used. We had conducted short term chronic toxicity tests using algae, daphnia and fish refered to USEPA's whole effluent toxicity (WET) test method to evaluate the river water samples in our previous studies. However, no toxicant was identified in these investigations. So, in the present study, we collected seven samples in Tokyo metropolitan area, Osaka/Kyoto and Tokushima, and toxicants were characterized using the procedure of Phase I of Toxicity Identification Evaluation such as pre-treatment using solid phase extraction cartridges. As a result, cations such as metal ions are found to mainly contribute to the growth inhibition of algae. For daphnia, both cations such as metals and organic compounds are found to be major contributors to inhibit the reproduction, while organic compounds are major contributors for the inhibition of hatching and survival of fish.
