Relative study of heavy metal contamination in fishes of buriganga river due to untreated tannery effluent and in fishes from another source in Bangladesh

This study was undertaken to assess the level of heavy metals and the extent of pollution in surface water, sediment and fishes of Buriganga River near the discharge point of tannery effluents. Water, sediment and two species of fish samples were collected by typical process. Those Samples were analyzed to determine the heavy metal content by Flame Atomic Absorption Spectrophotometer (FAAS). Accumulation levels in fish were then compared with the concentration levels of fishes collected from the local market. In Heteropneustes fossilis (Stinging catfish) average bioaccumulations of Cr, Pb, Cd, and Zn were varied from 437.85 to 8.4 mg/kg, 26.3 mg/kg to Below Detection Limit (BDL), 2.75 to 0.05 mg/kg and 338.5 to 29.7 mg/kg in dry weight respectively. While in Channa punctata (Spotted snakehead) average bioaccumulations of Cr, Pb, Cd, and Zn were varied from 81.05 to 1.35 mg/kg, 27.75 to 1.6 mg/kg, 2.9 to 0.4 mg/kg and 244 to 67 mg/kg in dry weight respectively. Mean concentration of metals in sediments were; Cr-271.6, Pb-16.02, Cd-0.43 and Zn-54 mg/kg in dry weight and in water these levels were Cr-0.285, Pb-0.056, Cd-0.002 and Zn-0.757 mg/L. Amongst the Heavy metals Cr recorded the highest concentration in the head of H. fossilis with a value of 437.85 mg/kg and Cd recorded the lowest in water with a value of 0.002 mg/L. This study was intended to evaluate the effects of tannery effluents on aquatic life and water quality at the discharged point of tannery effluents. Cr content which mainly comes from the tannery effluents was found excessively high in the Fishes of Buriganga River than that of Local Market in this study. These findings indicate a major threat to human health as the concentration of heavy metals was higher than the WHO approved standard level.