HEAVY METAL CONTENTS OF ONDA TANTALITE MINING AREA, NASARAWA STATE, NIGERIA

Heavy metal contents in soil from Onda tantalite mining area were studied. Thirty and ten soil samples were collected from the mining area and control site, respectively, using a hand auger. The soil samples were analysed for heavy metals; Cd, Co, Cr, Cu, Fe, Pb, Mn, Ni and Zn using atomic absorption spectrophotometer, AAS. The results obtained showed that the mean concentrations for the respective metals above were 9.38±2.98, 18.25±5.32, 40.29±8.47, 34.40±8.77, 1590.57±403.46, 53.10±11.65, 188.57±41.13, ND and 620.44±91.47 mg/kg in soils from the mining area and 6.40±1.99, 21.00±3.68, ND, 36.36±5.26, 1195.95±314.52, 31.24±6.93, 143.23±28.26, ND and 564.15±120.82 mg/kg for soils from the control site. The mean metal contents from the mining site were all higher than those from the control site due to mining activities, except for Co and Cu but were all lower compared to the recommended permissible limits by WHO except for Cd and Zn. The EF, CF, PLI, ERI and PERI evaluated for metals from the mining site show no imminent danger. However, there is the need for constant and regular monitoring of the level of heavy metals in soil from the site because of accumulation overtime, and soil remediation should be employed to take care of cadmium and zinc.