Bioaccumulation of metals in the edible catfish Heteropneustes fossilis (Bloch) exposed to coal mine effluent generated at Northern Coalfield Limited, Singrauli, India.

Metal accumulation in various tissues of Heteropneustes fossilis exposed to the effluent generated from an open cast coal mine was investigated. The contents of Fe, Mn, Cu, Zn, Ni, Pb, Cd and Cr in the effluent were above the permissible limits as suggested by the different pollution control agencies. Out of the eight metals investigated, accumulation (mg kg(-1) dry weight of tissue) of Fe was maximum in every tissues followed by liver (265.88 ± 49.89) > kidney (153.0 ± 65.85) > gills (50.66 ± 23.923) > brain (49.303 ± 5.11) > air breathing organs (27.98 ± 10.93) > skin (19.56 ± 2.53) > muscles (8.74 ± 0.83). This was succeeded by Pb in brain (39.35 ± 5.79), Zn in kidneys (27.04 ± 2.31), Mn in the gills (20.69 ± 3.044), Cu (12.53 ± 1.01) > Cr (5.10 ± 2.87) in liver and Cd in kidneys (2.18 ± 0.084). Liver and ABOs showed significant uptake of all the metals. Except Cu and Cr, accumulation of most of the metals by kidneys and gills were also significant. Accumulation of Fe, Cd, Pb and Cr in most of the tissues of exposed fish were above the permissible limits indicating their potential hazardous impact on fish as well as on fish consumers. Even in the tissues of untreated fish the concentrations of Fe (12.26-428.47), Cd (0.2-1.22), Pb (0.02-9.42) and Cr (1.14-11.05) were above the permissible limits. This clearly demonstrates greater bioavailability of these metals in the area.