Determination of Elemental Concentration of Natural Radionuclide in Soils of Industrial Communities, South-South Nigeria

The elemental concentration of natural radionuclides in soil of some communities in South-South Nigeria with history of oil spillage, gas flaring, oil bunkering and operation of illegal artisanal oil refining activities was determined and measured with gamma ray spectroscopy. The activity concentration values of radionuclides in soil were converted to elemental concentration values. The result showed that the mean value of elemental concentrations in the soil samples ranged from 1.44±0.34 to 2.58±0.26ppm for uranium, 5.60±0.81 to 8.33±1.16ppm for thorium and 0.35±0.03 to 1.54±0.06% for potassium. These mean elemental concentration values are respectively lower than the worldwide standard of 2.7ppm, 11ppm and 1.3ppm in the soil of the five sampled communities except for the potassium value in the soil at Bunu-Tai that was higher than the permissible standard by 0.24%. The Th/U elemental ratio in the soil samples at Eleme and Bunu-Tai communities are respectively 4.68 and 4.84 and are over 1.6 times higher than the theoretical standard value of 3.0 for normal continental crust indicating an enrichment of thorium and depletion of uranium radionuclides in these communities. The Th/U elemental ratio in the soil samples at Ban-Ogoi, Bodo and Giokoo communities are respectively over 1.4 times lower than the 3.0 standard for normal continental crust showing a depletion of thorium and enrichment of uranium in those communities. Relative depletion/enrichment of natural radionuclides occurred in soils of the sampled communities arising from alteration of natural processes by anthropogenic/metamorphic activities.