Use of Daphnia magna for the Microbioassay of Pesticides. I. Development of Standardized Techniques for Rearing Daphnia and Preparation of Dosage-Mortality Curves for Pesticides1

Abstract

Detailed study of optimal conditions of rearing and testing Daphnia magna Straus showed that it was possible to rear this organism under closely controlled laboratory conditions. Under these conditions asexual reproduction yielded a homogeneous population well suited for microbioassay of pesticide residues. It was found that some pesticides were extremely toxic to daphnids at concentrations as low as a few parts per trillion in water. Most of the pesticides tested showed LD₅₀ values below parts per billion. Directions for rearing daphnids and using them for bioassay are given, with dosage-mortality curves and LD₅₀ values for 56 of the more common pesticides.