Acute toxicity of copper cadmium and their mixture to tilapia (Oreochromis mossambicus)

Acute toxicity of copper and cadmium including median lethal concentration (LC50) of tilapia species (Oreochromis mossambicus).in static condition for a definite period of exposure was determined. The LC50 for 24 hours exposure to Cd and Cu and their mixture estimated graphically was found to be 1 mg, 2mg and 3mg/l, respectively. The LC50 of tilapia exposed for 72 hours exposure was found to be 2 mg/l where as for the same period to Cd it reached 4mg/l. Unlikely for Cu prolong exposure the LC50 values decreased proportionally with the exposure period. The uptake amount of metals was found to increase gradually with exposure concentration as well as period of exposure but accumulation did not follow the same pattern. The accumulated amounts were determined by Atomic Absorption Spectroscopy.