DETERMINATION OF MEDIAN TOLERANCE LIMIT (LC50) OF CHANNA PUNCTATA (BLOCH) FOR CADMIUM CHLORIDE

Abstract

The present investigation was undertaken to investigate the acute toxicity of cadmium, a heavy metal widely detected in the aquatic environment due to natural effects and anthropogenic activities, in freshwater teleost, Channa punctata (Bloch). The experiments for the bioassay were performed in semi-static test condition according to the standard guidelines. The behavioural changes in the fish were observed for all tested concentrations of the metal. The data obtained for bioassay were analyzed for median lethal concentrations (LC50) of the metal by SPSS computer software. The LC50 values, estimated by SPSS, with 95% confidence level were found to be:20.589 (18.326-23.221), 17.133 (14.840- 19.734), 11.815 (9.696 – 13.850) mg/L and 9.908 (7.635-12381) mg/L for cadmium chloride at 24, 48, 72 and 96 h exposure, respectively.