Inspection of a fish poisoning accident in Gutian reservoir in Fujian

On June 22nd in 2004, we were entrusted by the local fishery management station to investigate a large area death accident of fish in the fishery farm at Gutian Reservoir in Fujian. We collected water and fish samples from 5 stations in the accident area. By comparing the water and fish organs samples from the control site, we basically excluded the pollution causes such as acid-base chemicals, hypoxia, heavy metals, fecal (not ammonium poisoning), fluoride, volatile phenol and water quality (elevated sulphide and bacterial). Our investigation result showed that the accident was caused by the pollution of one organic chloride pesticide:endosulfan, and it was a intentional poisoning action. As environmental pollution indicating organisms, plankton and microorganisms were proved to be essential for such investigation. Water quality was indicated by the change of species structure, abundant and morphology of phytoplankton and zooplankton. We also learned that it was helpful for our investigation that the fish farm owner could reserve the dead sample (freezed) and report to the local fishery management department in time. After the fishery administrative departments and agencies in the fishery receiving the report, they should timely notify the fishery environment monitoring and other relevant qualification technical units in accident sample identification, in order to ensure the effective handling of fishery pollution accidents, help farmers to retrieve the economic loss, and preserve the fishery ecology environment.