ABSTRACT
Aquatic studies have been carried out with the pesticide trichlorphon (SoldepTM), a product used for zooplankton control in commercial fish culture. Under laboratory conditions, acute toxicity values were determined for different fish species and aquatic invertebrates. Clinical signs and the pathological and anatomical picture of intoxication were also described. Aquatic field tests were done in 0.1 ha mesocosms of average depth 1 m. The pesticide was applied into these ponds at a range of concentrations; 0.05–5.0 kg ai ha−1. Regular physicochemical and biological analyses of water were carried out, and also monitoring of the persistence of pesticide residues in individual components of the pond ecosystem (water, bottom sediment and fish). Residues of trichlorphon and its metabolite dichlorvos were determined by gas chromatography. Pond water samples were tested by bioassay with Daphnia magna at the same time. Results of both determinations were practically identical. Based on these data, a bioassay using Daphnia magna is recommended as a sufficiently sensitive method for the evaluation of residues of trichlorphon and dichlorvos in water. From the laboratory bioassays and aquatic field tests, the principles and protective measures for trichlorphon used in commercial fish culture have been defined.
