Effects of acute cadmium poisoning on survival, its residual values and histopathology in certain organs of a freshwater airbreathing fish, Channa punctatzcs (BLOCH) were investigated. The threshold concentration, MATC and LCm values obtained from 96 h static bioassay, revealed that Channa is more susceptible to cadmium ions at higher temperature. The atomic absorption spectrophotometric determination of cadmium residues differed significantly in organs of specimens having survived and died after 96 h of exposure. The gill accumulate the highest amount of cadmium, the liver accumulated a slightly smaller amount than the gill, while the kidney accumulated the least.
The histopathological lesions subjected to sublethal (5.2 mg/l Cd) and lethal (8.4 mg/l Cd) concentrations of cadmium were: detachment and rupture of lamellar epithelium, collapse of pillar cells and hypertrophy in mucus producing gland cells in the gill; tacuolization and coagulative necrosis in hepatic cells of the liver; and expansion, necrosis and accumulztion of cellular debris in renal tubules of the kidney. The probable causes for death of fish due to cadmium ions have been discussed.