Acute toxicities of diethyl ether and ethanol extracted Nerium indicum leaf to the fish, Heteropneustes fossilis

A four-day static renewal acute toxicity test was performed to determine the LC 50 value of ethanol and diethyl ether extracted Nerium indicum leaf for the freshwater fish, Heteropneustes fossilis. The LC 50 values, their upper and lower confidence limits and slope functions were calculated. The LC 50 values for ethanol extracted Nerium indicum leaf at various exposure periods are 155 mg/L for 24 h; 115 mg/L for 48 h; 87.5 mg/L for 72 h; and 60 mg/L for 96 h. The LC 50 values for diethyl ether extracted Nerium indicum leaf at various exposure periods are 38 mg/L for 24 h; 27 mg/L for 48 h; 20 mg/L for 72 h; and 14 mg/L for 96 h. The toxicity of Nerium indicum leaf extracts (both ethanol and diethyl ether extracted) exhibits a positive correlation between fish mortality and exposure periods (mortality of fish at a given concentration is increased with increased duration of exposure). Key words: Toxicity, Fish, Nerium, LC 50