Bioaccumulation of chromium, manganese, nickel and lead in the tissues of the moggel, Labeo umbratus (Cyprinidae), from Witbank Dam, Mpumalanga

Abstract

This paper focuses on the extent of Cr, Mn, Ni and Pb bioaccumulation in the different tissues of a cyprinid fish, namely the moggel (Labeo umbratus) from Witbank Dam in the Upper Olifants River catchment. The dependence of bioaccumulation on size, gender and seasons was specifically addressed. Bioaccumulation of Cr, Mn, Ni and Pb varied between the gills, liver, muscle and skin. The gills generally had the highest metal concentrations, due to their intimate contact with the environment and their importance as an effector of ionic and osmotic regulation. The liver, in its role as a storage and detoxification organ, can also accumulate high levels of metals. Muscles and skin accumulated much less metal concentrations. These two organs must be included in biomonitoring programmes because they are consumed by the general public. Accumulation of the metals decreased with an increase in fish length. Therefore, the smaller the fish the higher the body load of metals due to various bioaccumulation processes.

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