LEVEL OF HEAVY METALS AND THEIR BIOAVAILABILITY IN SOIL

ABSTRACT

The research was designed to ascertain the concentrations of heavy metals (Cu, Pb, Zn, Fe) from soils in the vicinities of Asaba industrial area of Delta State, Nigeria. Soil samples were randomly collected from four selected Industrial locations, The samples were taken from each location at depths of 0-15cm, and 15-30cm with the aid of the Auger, sequential extraction was used to fractionate four heavy metals (Cu, Zn,  Fe and Pb) from four contaminated Industrial soils into six operationally defined groups: exchangeable, carbonate, Fe -Mn oxide, organic, residual and digestion, Standard laboratory procedures were adopted to determine the concentration of heavy metals using Atomic Absorption Spectrophotometer (AAS), the results revealed that the concentrations of metals in soil samples in mg/kg ranged from 0.01-0.05 for Cu; Pb, 0.01 –0.12; Zn, 0.2-3.6; Fe, 0.8–27.8 Significant  variation in Concentrations was observed for all metals across the locations and the degree of pollution varies with the level of industrial activities but were all within tolerable limit.