Assessment of Radiological Hazards Indices in Vegetables Grown Around Ririwai Tin Mines, Kano State, North Western Nigeria

Abstract

Mining industry in Nigeria provides economic benefits of wealth creation and employment opportunities. Presently there are numbers of artisanal and large scale mining activities going on across Nigeria and most of these artisanal miners currently under take only surface mining. The process produced large volumes of tailings and waste that may contain naturally occurring radioactive materials (NORMs). Some of the NORMs are soluble in water and have the tendency to leach into water bodies and farm lands.    This work assessed the radiological hazard indices in vegetable grown around Ririwai Tin Mine Kano State North Western Nigeria using Direct Gamma Spectroscopy (NaI (Tl)), The results shows that the mean activity concentration in vegetable samples were 259.25±4.77, 28.05±4.97 and 54.56±2.58Bq/kg respectively for ⁴⁰K, ²²⁶Ra and ²³²Th, the mean absorbed dose rate was 45.043±1.98nGyh^-1 the mean committed effective dose for ⁴⁰K is 0.091±0.002mSv/year, ²²⁶Ra has a mean committed effective dose of 0.471±0.083mSv/year while ²³²Th has a mean committed effective dose of 0.753±0.036mSv/year. The total committed effective dose in vegetable has a mean value of 1.320±0.125mSv/year. The risk estimated for fatality cancer, lifetime  fatality cancer risk, severe hereditary effect and life time hereditary effect in vegetable were 7.26 x 10^-5, 5.29 x 10^-3, 2.60 x 10^-6 and 1.84 x 10^-4 respectively. The values obtained in this study are relatively high such that consumption of vegetable grown in the area could pose  radiological health hazards.

Keywords: Activity Concentrations, Absorbed dose, Committed effective dose, Risks