Bio-accumulation of selected metals in African sharptooth catfish Clarias gariepinus from the lower Olifants River, Mpumalanga, South Africa

The level of metal (Cr, Cu, Mn, Ni, Pb and Zn) bio- accumulation in tissues (muscle, gill, kidney, liver and gonads) and bile of the African catfish Clarias gariepinus, from the lower Olifants River was investigated. These metals were detected in all the tissues as well as in the bile, with the highest concentration found in either the gills, liver or gonadal tissue. The lowest concentration was usually detected in the muscle tissue. Although statistic comparisons revealed no significant differences between the localities, fish from the Selati River (Locality 1) generally had higher metal levels than fish from the localities along the Olifants River inside the Kruger National Park. The higher levels in the fish from the Selati River may be attributed to anthropogenic activities resulting in point and/or diffuse sources of metal pollution. These sources should be identified and reduced.