Endosulfan sulphate interferes with reproduction, embryonic development and sex differentiation in Daphnia magna.

Endosulfan sulphate is the transformation product of endosulfan and it is the most frequent form of surface water contamination with endosulfan. The aim of this study was to evaluate the possible effects promoted by endosulfan sulphate in changes on the life cycle, embryo development and sex differentiation of Daphnia magna. The endpoints used were moulting frequency, fecundity, growth, developmentally abnormalities and sexual differentiation. The nominal concentrations of endosulfan sulphate tested ranged from 9.2 to 458.7 microg L(-1). Endosulfan sulphate promoted a significant decrease of the offspring number in all concentrations. Results showed a reduction of the size of females, together with a decrease in moulting frequency. Furthermore, an increase in embryo deformities was observed at all concentrations tested. Above a concentration of 91.7 microg L(-1) there was an increased production of males. The results suggest that endosulfan sulphate interferes with the life cycle and sex determination of the crustacean D. magna.