It is well known that, heavy metals have affinity for different compartment in soil. The risk associated with the presence of metals in soil is their potential ecotoxicity and ability to enter the food chain. Total metal content of a soil is inadequate for predicting the toxicity of heavy metals in soil. Hence, sequential extraction was used in this study to fractionate five heavy metals (Al, Cd, Cu, Pb and Zn) in soils collected from a mining area in order to determine the fraction of the total metal content that is bioavailable. Results showed that aluminium, lead and zinc were mostly associated with long-term mobile fraction (F3, F4 and F5), cadmium was mostly associated with the exchangeable fraction (F1) while copper was widely abundant in the oxidized form (F4). The apparent mobility and bioavailability for these five heavy metals in the studied soils were in the order: Cd>Zn>Pb>Cu>Al. This implies that cadmium has the highest mobility in the studied soils.
