G. DEVI, D BARUAH AND B K BARUAH
Abstract
Acute toxicity of two different types of effluent of galvanised industries were determined with freshwater fish Cyprious carpio by static bioassay experiment for 24 hrs, 48 hrs, 72 hrs and 96 hrs. Two different LC 50 values were observed indicating different toxic nature of the two effluents. The LC 50 values were 13%, lo, H% nud 5.5% observed in one industry and in other LC 50 values were 14%, 12.5% 11% and 9.5%. Fish behavioural changes were also noticed during the experiment. The fishes showed occassional jerking movement, fast opercolar movement and loss of equilibrium. The physicochemical analysis of two different effluetif showed two types of pH value, one being alkaline (9.8) and the other acidic (4.3) high amount of chemical oxygen demand, Zinc, Iron, trace amount of chromium, lead and low dissolved oxygen concentralion lead jug to toxic nature of effluent to the receiving ecosystem.