Acute Toxicity of Endosulfan, Malathion and Carbaryl, and their Sublethal Effects on Growth of Channapunctatus bloch in Cachar District, Assam, India

The 24, 48, 72 and 96 h LC 50 values of endosulfan, malathion and carbaryl for the fish Channapunctatus Bloch were estimated by log-probitanalysis.Thesewere 0.0182, 0.0025, 0.0011, and 0.0007 mg l -1 ,respectively, for endosulfan; 5.5,2.3,1.6, and0.9 mg l -1 , respectively, for malathion; and 10.9, 8.3, 8.0, and 7.5 mg l -1 ,respectively, for carbaryl. When C. punctatus was exposed to 1/3 and 1/10 of the 96 h LC 50 values of these three pesticides for 21 days, the body weight of fishes decreased in both sublethal concentrations of the three pesticides when compared with those in the control, which gained weight during the experiment. The reductions in growth were statistically significant as revealed by one-way ANOVA and Tukey tests.