Impact of Water Pollution on Fish Physiology - A Study

Abstract

The freshwater air-breathing teleost, Channa punctatus were exposed to mercuric chloride (0.15 ppm) and cadmium chloride (35.5 ppm) for 1, 2, 7, 15 and 30 days so as to determine short and long-term effects of sub-lethal doses of these industrial pollutants on different haematological parameters. The selection of pollutants and their concentrations was based on the real data, in relation to the degree of water pollution of Damodar River. Blood samples were collected from the fishes exposed to various exposure periods for each pollutant and the blood glucose, haemoglobin content, cholesterol, HDL-cholesterol, LDL- cholesterol, VLDL- cholesterol, triglycerides, total RBC and WBC counts were measured. The blood glucose, haemoglobin content, total RBC and WBC counts progressively decreased. Blood cholesterol, HDL-cholesterol, LDL- cholesterol, VLDL-cholesterol and triglycerides were also depleted. Linear regression analysis with appreciable values of R2 and tratios revealed that the values of different blood parameters were reduced radically with the progress of days, except haemoglobin, signifying negative impact of pollutant of HgCl2. Strong correlation between different blood parameters calls for that adverse variations. Histopathological changes in the hepatopancreas induced by the heavy metals like mercuric chloride and cadmium chloride include degeneration of hepatic cells, clumping of cytoplasmic materials, displacement of nucleus towards the periphery, derangement of the pancreatic acini and coagulation of blood in the sinusoids. Analysis of experimental data suggests the depletion of energy resources and disturbance of the metabolic pathway as indicated by the adverse effects on haematological parameters and histopathological lesions in the haepatopancreas.