METAL SPECIES, MOBILITY AND BIOAVAILABILITY IN AN OIL IMPACTED SOIL FROM IKOKU AND ALAOJI AUTOMOBILE SPARE PARTS MARKETS, NIGER-DELTA NIGERIA

Abstract

The species, distribution, mobility and bioavailability of heavy metals (Pb, Cd, Zn,Cu, and Cr) were investigated by the determination of chemical forms of the heavy metals insoil from automobile spare parts markets in Alaoji and Ikoku, Niger Delta, Nigeria.Sequential extraction was use to fractionate heavy metals from the samples into fiveoperationally defined groups; exchangeable fraction, fraction bound to carbonate, Fe/Mnoxide bound fraction, fraction bound to organic matter and residual fraction. Moreover, theheavy metal labilities in soils were evaluated by extraction with EDTA. Analysis of themetals was carried out by UNICAM SOLAAR 32 atomic absorption spectrophotometer. Znand Cr are mostly abundant bound to Iron and Manganese oxides with results ranging from42.210 to 37.300 % and 50.260 to 54.780 % respectively. Cd and Pb are distributed more atthe exchangeable phase in the entire sample with the fractions that ranges from; 58.809 to61.670 %, Cd and 39.600 to 40.760 %, Pb . The results were interpreted in terms of theenvironmental mobility and bioavailability of the metals. The results of this study suggest thatthe mobility and availability of the metals are in the following order: Cd > Pb > Cr > Zn > Cu.This potential availability of the heavy metals indicates that metals have contamination risk inAlaoji and Ikoku environment which can contaminate water supplies and transferred to foodchain.