Effect of cadmium on Haematological changes in a freshwater catfish, Heteropneustes fossilis
P Bujjamma, P Padmavathi
Toxic pollutants such as heavy metals are particularly harmful to aquatic life. They can take up metals concentrated at different levels in their different body organs. Thus heavy metals acquired through the food chain as a result of pollution are potential chemical hazards and threatening consumers. The effects of exposure to any hazardous substance depend on the dose, exposure time, the mode of exposure, personal habits, traits, and presence of other chemicals. Therefore it is important to monitor heavy metals in aquatic environment, especially in fish. Increased loads of heavy metals in waste water may increase the risk of ground water contamination. The present work is designed to evaluate effect of cadmium on haematological parameters of Heteropneustes fossilis. The main haematological alteration resulting from exposure of H. fossilis to various concentrations of cadmium for 7, 14 and 21 days include significant decrease in haematocrit and haemoglobin concentration and in red blood cell counts. The white blood cell counts increased followed by a change in the composition as seen from the differential white blood cell counts. MCHC exhibited a significant decline when compared to control fishes. MCV and MCH values were found to exhibit a significant rise in treated fish than in control fish. The changes in the hematological parameters indicated that they can be used as indicators of cadmium related stress in fish on exposure to elevated levels in the water.