Toxicity of some heavy metals on blood characteristics of freshwater fish Clarias batrachus

The environment is impacted by ongoing pollution, caused by both natural as well as environmental factors such as industrialization and mining. Heavy metals causes as major problem because they are toxic and tend to accumulate in living organisms. So the present study was conducted to determine the effects of sublethal concentrations of ZnSO4, CdCl2 and CuSO4 as a pollutant on some haematological parameters of Clarias batrachus were exposed to three sublethal levels. Sublethal concentrations used were 6.5 ppm for cadmium, 4.6 ppm for Zn and 0.7 ppm for Cu. The results obtained revealed that there was significant difference in hematocrit, Exposure of Clarias batrachus to sublethal concentrations of Zn and Cd resulted in significant decrease (p < 0.05) in erythrocyte count and haemoglobin content, while there was a slight increase in case of copper. The microscopical observations showed that exposure of Clarias batrachus to sublethal concentrations of heavy metals 6.5 ppm for cadmium, 4.6 ppm for Zn and 0.7 ppm for Cu resulted in some changes in the morphology of the R.B.Cs which tended to lose its ellipsoidal shape acquiring different shapes (poikilocytosis or anisocytosis).