VARIATIONS IN ELEMENTAL AND RADIOMETRIC CONCENTRATIONS OF SOILS AROUND A MINING SITE IN SOUTHWESTERN NIGERIA

Abstract

Soil samples from a mine site in Ijero, Ekiti State South-west Nigeria, were investigated for their elemental and radionuclides (40K, 232Th and 238U) concentrations to assess the contaminations levels. Twenty (20) soil samples were randomly collected using Dutch stainless steel Auger around the mine sites but largely dictated by the miners activities and locations. Elemental and radioactivity (40K, 232Th and 238U) components of the soils were determined using particle induced X-ray emission and Gamma spectrometers respectively. To assess the level of contamination and the possible anthropogenic impact, the pollution indices and the geo-accumulation indices of some elements were calculated. Twenty-six elemental (Na, Mg, Al, Si, Cl, K, Ca, Ti, V, Cr, Fe, Cu, Zn, Ga, Rb, Zr, Nb, Cd, Sn, Ba, Nd, Bi, Pb, Pa, Th and U) concentrations were quantified. Average concentrations of these toxic elements; V (327 μg g-1), Cu (276 μg g-1), Nb (806 μg g-1), Cd (785 μg g-1), Pb (394 μg g-1), Th (473 μg g-1) and U (500 μg g-1) were particularly high, exceeding recommended values. Activity concentrations of the radionuclides ranged from 1 to 3, 4 to 10 and 415 to 15520 kBq kg-1 for 232Th, 238U, and 40K respectively with an average exceeding world limit which could lead to possible radiological consequences. Geo-accumulation and the pollution risk factor studies revealed that Pb could pose significant potential health risk to the miners and ecosystem.

Keywords

• elemental
• pollution
• radiometric
• soil
• toxicity