Interactive toxic effects of agrochemicals on aquatic organisms

The effects of three common agrochemicals, lindane, methyl parathion and at razine, on crustacean Daphnia magna, alga Selenastrum capricornutum and mar ine bacterium Vibrio fischeri were investigated in this study. Methyl parat hion was the most toxic compound towards all three organisms, while lindane was more toxic to Daphnia magna and Vibrio fischeri than atrazine, and atr azine was more toxic to Selenastrum capricornutum than lindane. Among the t hree aquatic organisms, Selenastrum capricornutum was most sensitive in det ecting lindane and atrazine toxicity, while Daphnia magna was most sensitiv e in detecting methyl parathion toxicity. The interactive effects of the pe sticides were also investigated. The interactive effect between lindane and methyl parathion on survival of Daphnia magna was synergistic, while the o nes between lindane and atrazine and between methyl parathion and atrazine were generally additive. The interactive effect of the three pesticides app lied together on Daphnia magna was synergistic. The interactive effect of t he three pesticides on the growth of Selenastrum capricornutum was antagoni stic with few cases of addition, while the effect of all the three pairs of pesticides on algal growth was also antagonistic. The interactive effect o f lindane and methyl parathion on Vibrio fischeri was additive. (C) 1999 IA WQ Published by Elsevier Science Ltd. All rights reserved.