Determination of radiological hazard indices from surface soil to individuals in Angwan Kawo Gold Mining Sites, Niger state, Nigeria

Abstract

The determination of radiological health hazard indices from soil samples has been carried out to assess the environmental impact assessment of gold mining activities in Angwan Kawo community in Niger state, Nigeria using NaI (TI) gamma ray spectroscopy. The radionuclide concentrations were determined using the sodium iodide [NaI (TI)] detector with a low background configuration. The results obtained show that the activity concentrations of 226 Ra, 232 Th and 40 K ranged from (20.43±0.04 to 86.45±3.83) (Bq/kg), (19.79±0.83 to 69.80±2.60) (Bq/kg) and (52.63±1.07 to 714.32±16.25) (Bq/kg) at the goldmine and (30.54±0.48 to 82.39±5.83) (Bq/kg), (54.63±0.83 to 114.92±2.91) (Bq/kg) and (290.74±7.08 to 600.44±16.24) (Bq/kg) at the processing zone, respectively. The results obtained were compared with the world mean values of 35, 30 and 400 Bq/kg, for 226 Ra, 232 Th and 40 k, respectively. To assess the radiological hazard of the gold mining site the radiological hazard indices i.e., absorbed dose (D), annual effective dose equivalent (AEDE), radium equivalent activity (Raeq), external hazard index (Hex), internal hazard index (Hin) and gamma representative index (I) were calculated and found to be below the internationally recommended values. Based on this study finding, for the purpose of protection of mine workers and the public it is highly recommended that these sites should be regularly monitored and controlled in order to avoid any radiological impact to the population. Keywords: Gamma spectrometry, Gold mine, Processing zone, Hazard index