Evaluation of Radiation Hazard Indices and Excess Lifetime Cancer Risk Due To Natural Radioactivity in Mined Tailings in Some Locations in JOS Plateau State Nigeria

Abstract

The radiological effects of mined tailings in some locations in Jos Plateau State have been estimated. The samples were collected from 14 different sites. The radio nuclides concentrations in the tailing samples were measured using gamma spectroscopy method. The average values of 𝑅𝑎226,𝑇ℎ232 𝑎𝑛𝑑 𝐾40 obtained were 762.4Bqkg⁻¹, 17258.3Bqkg⁻¹ and 5901.4Bqkg⁻¹ respectively. These radioactivity concentration values obtained are far above the world average value of 400Bqkg-1 for𝐾40, 35BQkg-1 for 𝑅𝑎226 and 30Bqkg⁻¹ for 𝑇ℎ232 by UNSCEAR. The hazard indices and excess lifetime cancer risk were estimated using standard analytical methods. The average values obtained for annual gonnadal equivalent dose, radium equivalent, external hazard index, internal hazard index, representative gamma indices, annual effective dose equivalent (outdoor), annual effective dose (indoor) and excess lifetime cancer risk respectively were 76348.49Svyr⁻¹, 25896.16Bqkg⁻¹, 70.20Svyr⁻¹, 71.98Svyr⁻¹, 181.60Svyr⁻¹, 86250.95μSvyr⁻¹, 13877.58μSvyr⁻¹ and 48571.52 x 10⁻³. The values when compared with the corresponding world recommended levels were found to be far above the standard limit and as such, radiation exposure to the miners, those that process it and those that live very close to the study area will pose significant health hazard to them. The results of this study show the importance to investigate the radioactivity levels in drinking water, vegetables grown and cattle reared in the study area