Abstract

Surface soil samples collected from four Industrial work sites in Nsukka Urban Industrial cluster areas, South- East Nigeria were investigated for levels, spatial distribution and ecological risk of Cadmium (Cd) and Lead (Pb). A total of 200 samples were analysed using Flame Atomic Absorption Spectrophotometer (AAS) following wet digestion using 65% Nitric acid. The results revealed Cadmium and lead concentration levels in surface soil from the area studied are unevenly distributed spatially showing a range of 1.855-2.798 mg/kg for Cd in Automobile (AM) work sites, 0.068-0.084 mg/kg in Motor Parts (MP) Fabrilation sites,  0.000-0.020 mg/kg in wood work (WW)  sites and 0.218-0.259 mg/kg in Aluminium work (AW) sites. The respective mean concentrations for Pb were 1.913,1.410, 1.384, 1.114, 0.086, 0.074 and 1.020, 0.099  mg/kg. Apart from WW samples, Cd levels in all the samples were above the maximum allowable unit of 0.07mg/kg set by World Health Organisation (WHO). Pb levels exceeded the maximum allowable unit of 0.05 mg/kg in all the samples suggestive of increased Pb content in soil due to anthropogenic interactions. The RI of AM worksite showed high risk while MP fabrication worksite had moderate ecological risk. The contribution of Cd to the risk potential was much.

Key words: Industry, surface soil, pollution, Cadmium, lead, ecological risk, worksite, Nsukka.