EFFECTS OF CHLORPYRIPHOS (20% EC), AN ORGANOPHOSPHATE PESTICIDE ON GILL AND LIVER OF A CATFISH HETEROPNEUSTES FOSSILIS, (BLOCH, 1794)

Organ-histopathology appears to be an effective and sensitive monitoring tool to measure and analyse the health condition and level of pollution in aquatic ecosystem. The present study is an attempt to evaluate the toxic effects of Chlorpyrifos, an organophosphate pesticide on the gill and liver of a cat fish Heteropneustes fossilis. A long term experiment was performed for 60 days by using 1/10th and1/20th of 96 hrs. LC50 value of Chlorpyrifos as sub-lethal concentrations, which were 0.178 mg/l and 0.089 mg/l respectively for H. fossilis. Simultaneously a control (exclusively toxicant free medium) group was also conducted in each species for comparison. The gills of exposed fishes showed alterations like degeneration of secondary gill lamellae, massive vacuolization, blood congestions and dilation of blood vessels etc., whereas liver of exposed fish exhibited changes like cytoplasmic degeneration, degeneration of hepatocytes, vacuolization and haemorrhages.