Physicochemical Parameters and Heavy Metals Characterization of Soil from Okpella Mining Area in Edo State, Nigeria

The present study examines the physicochemical parameters and heavy metal contents of soil from Okpella Mining  Area in Edo State. Top soil samples and   control  samples from about 200m from the mining area were analyzed for  their heavy metals content using Atomic Absorption Spectrometer (AAS) techniques. The pH, electrical  conductivity and organic matter were determined using standard procedures. The soil pH ranged from 6.8 to 7.9  which show slightly acidic to alkaline conditions. The concentrations of the metals in mg/kg were as follows: Cu  (23.03 to 170.83), Pb (3.50 to 10.59), Cd (0.70 to 1.93), Cr (0.75 to 8.74), Ni (5.0 to 34.52), Zn (3.29 to 25.46), Mn  (3.49 to 22.50), Fe (22.03 to105.67), Co (9.99 to 64.43) and As (0.35 to 1.20). Inter elemental correlation showed  that most of the metals investigated were of common origin. The mean concentrations of the metals were in the  general order: Cu>Fe> Co> Ni> Zn>Mn>Pb>Cr>Cd>As. The concentrations of the metals at mining area were  generally higher than control. With the exception of Cd, the concentration of other metals analyzed were within safe  limit based on WHO standard. Results from pollution index assessment also show that Cd has higher degree of  contamination. There is therefore need to monitor agricultural activities going on in this area so as to guard the safety  of man and organisms in the area