BIOACCUMULATION OF HEAVY METALS AND THEIR GENOTOXIC IMPACT ON FRESHWATER MUSSELS FROM RIVER CHALLAWA

Abstract

Several potential genotoxins found in water samples arise from anthropogenic activities which poses serious environmental concerns worldwide. Water and mussel samples were collected from four (4) sampling sites along River Challawa on the basis of the different activities taking place. Atomic Absorption Spectrophotometry has shown elevated levels of various heavy metals (cadmium, chromium, copper, lead, manganese and nickel) above permissible limits in the water samples. In order to explore the genotoxic impacts of these metals, a genetic bioassay was employed. Hemolymph was extracted from freshwater mussels and used to assess DNA alterations in using comet assay. Significant levels of tail DNA percentages as a result of migration of damaged DNA in hemocytes of freshwater mussels was observed. Genotoxic assessment of the water in freshwater mussels using comet assay also revealed mild DNA damages. The findings therefore showed that a combination of physicochemical analysis along with the toxicity assessment (using bioassays) would provide valuable and more realistic information about the toxicity of chemical pollutants present in the water samples.