Abstract:

In order to estimate environmental effects and the associated health risk of some of the metals determined in stream sediment samples in the mining area, the abundance of fractions of some of these metals: Cd, Pb, Fe, Cr and Cu that are bioavailable were determined using the modified Tessier extraction scheme. X-ray fluorescence spectrometer (XRF) was used in determining the total concentration of metals in sediments while metals concentrations in extracted fractions were determined with the use of atomic absorption spectrophotometer (AAS). Results obtained revealed different metals to be partitioned in different percentages in the fractions. The bulk of the metals were retained in the residual fraction for metals like Pb, Cd, Cr and Fe while only Cu has a greater percentage of the metal retained in the fraction bound to organic matter and sulphide and this is due to the affinity of the metal to organic compounds reacting to form stable complexes. Partitioning of the metals in the labile fractions is a measure of their bioavailability in sediments to benthic organisms.

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