Effect of heavy metals at dna level of clarias gariepinus burcell, 1822 (African catfish) collected from tannery waste polluted area and local markets

Abstract

This research was undertaken to determine the amount of heavy metals in soil, water and fish samples from tannery waste affected areas of Hazaribagh. In addition, to know whether these heavy metals have any impact at the DNA level of this fish. Besides, samples were collected from two local fish markets. As control, sample from a reputed farm was selected. The quality of water in the tannery waste polluted area was much below than the standard level. The DO is 0.3 mg/l which gradually decreasing in comparison to previous studies. The below standard physico-chemical features of tannery waste polluted water are becoming a threat to the aquatic organisms living in these water body. High concentration of heavy metals like Pb, Cr and Cd are found in the sample fishes. Unexpectedly Cr was present 26 times higher than the normal limit to the control fish. In the fish from tannery waste water, the amount of Cr was about 200 times more than the normal level. A number of polymorphism was observed in four samples after RAPD analysis. Presence and absence of some bands indicated deletion and newly originating DNA fragments. The alteration at DNA level was probably due to accumulation of high level heavy metals. The presence of high amount of heavy metals in fish muscles is becoming a threat not only for the fishes but human health also. Therefore, the people should avoid African catfish those are selling in the local market and even from farms.