Study of Heavy Metal Distribution in Soils Impacted with Crude Oil in Southern Nigeria

The study presents the levels and enrichment factors of heavy metals in soils of southern Nigeria that have received significant impact of crude oil spillage. The results revealed that the concentrations of heavy metals in the examined soils fitted into levels found in agricultural soils except for cadmium. Heavily impacted sites showed elevated levels of heavy metals compared to less impacted sites and background levels. The mean enrichment factors for Cd, Cu, Cr, Pb, Mn, Ni, and Zn were 37.3, 2.8, 14.4, 14.0, 0.77, 5.4, and 1.27 for topsoil and 37.5, 1.30, 7.81, 1.59, 4.12, and 1.28 for subsoil, respectively. This clearly indicates that there is gradual build-up of heavy metals in these soils as a result of the oil spillage and related anthropogenic activities in this area.