The Effect of Cypermethrin, Chlorpyrifos, and Glyphosate Active Ingredients and Formulations on <i>Daphnia magna</i> (Straus)

Abstract

Acute effects of active ingredients (a.i.) and formulations (F) of widely used pesticides were assessed by means of the <i>Daphnia magna</i> toxicity test. Studied pesticides were the insecticides, cypermethrin and chlorpyrifos, and the herbicide, glyphosate. Results were analyzed and compared according to statistical endpoints (LCx) and log-probit regressions of toxicity data. The potency of acute toxicity followed the order: chlorpyrifos F > chlorpyrifos a.i. > cypermethrin F > cypermethrin a.i. ≫ glyphosate F > glyphosate a.i. Three to five orders of magnitude differences between the toxicity (µg/L to mg/L) of insecticides and the herbicide were observed. A pairwise comparison between a.i. and F indicated that all formulations were more potent. Additionally, for the case of glyphosate, evidence suggests that the adjuvant contributes to formulation toxicity rather than to the enhancement of a.i. potency.