Screening of organophosphate insecticide pollution in water by using Daphnia magna.

A simple and rapid screening method using Daphnia magna Straus (water fleas) on the basis of their immobilization was developed for detecting pesticide pollution. The laboratory testing of the toxicity of 11 organophosphate insecticides to D. magna determined 50% inhibition concentration of mobility at 48 h of exposure (48-h EC50) of 0.19 to 2.6 microg/L. The mobility of D. magna was inhibited in several river and stream waters sampled from May 1995 to February 1998 in Tokyo. Chemical analysis of the waters revealed that they were polluted by sub-ppb or ppb level of organophosphate insecticides. A significant relationship was observed between the immobilization of D. magna and the pollution level of the river and stream waters. The D. magna test could be used as a low-cost preliminary screening method for insecticide pollution.