detection of acute toxicity test (lc50) pesticide chlopyrifos in gold fish (carassius auratus) and comparison its toxicity with other organophosphate toxicity

chlorpyrifos is one of the organophosphate pesticides that are commonly used to control insects in domestic activities and many agricultural farms that are located in close to water sources. hence, the present study, investigate the lethal toxicity of this pesticide. in this study, fish were treated in groups of 21 with different concentrations of chlorpyrifos (aria brand with active ingredient 40/8% ec) for 96 hours and mortality was recorded. toxicity tests were determined by probit statistical analysis in software spss, version 16. at the end of 24 hours, mortality was 100% in fish with a concentration of 200 mg/l chlorpyrifos. lc50-96h this pesticide was calculated 83.2 mg/l. however, mortality was observed 100% for diazinon and deltametrin at the end of 96 hours. lc50-96h diazinon and deltametrin were less than chlorpyrifos that shows diazinon and deltametrin have more toxicity in comparing with chlorpyrifos. finally, carassius auratus is a suitable model of cyprinidae that constitute a big group of rearing fish and because of chlorpyrifos lower toxicity, seems to using of this pesticide stead other common pesticide had been low danger in agricultural fields.