Determination of acute toxic effects of carbamate pesticide carbaryl on narrow clawed crayfish ( Astacus leptodactylus Esch. 1823)

This study is concerned about the determination of 24,48, 72 and 96 hour LC50 values of carbaryl, a toxic pollutant on aquaous system coming from agricultural activities, on Astacus leptodactylus (Esch. 1823). In the present study, the semi static acute toxicity test method was used. The behavioral changes of the crayfish were monitored after exposed to carbaryl different concentrations. Bioassay results were evaluated using the U.S. E.P.A. LC50 computer program based on Finney?s Probit Analysis Method. 24, 48, 72 and 96 h LC50 (95% confidence limits) values for crayfish exposed to carbaryl were 0.44 mg/L (0.39-0.63 mg/L), 0.34 mg/L (0.28-0.40 mg/L), 0.28 mg/L ( 0.21-0.34 mg/L), 0.24 mg/L (0.18-0.29 mg/L) , respectively. The crayfish exposed to carbaryl were increased their movement when compared to control group. And the crayfish was observed to upside down before death.