Assessment of Human Exposure Risk to 226Ra, 40K and 232Th within Soil of Artisanal Gold Mine Using RESRAD Code

Estimating the morbidity excess cancer risk (ECR) from internal and external exposure to naturally occurring radionuclides ( ²²⁶ Ra, ²³² Th, and ⁴⁰ K) in the soil from three artisanal gold mining and resident agricultural regions in Niger State, North Central Nigeria, is the aim of this study. The activity concentration of naturally occurring radionuclides in soil was selected from the last reports. The excess cancer risks from the exposure to these radionuclides were estimated by the application of Residual-RADioactivity (RESRAD) code. The results obtained in this report show that the calculated maximum morbidity excess cancer risk from ²²⁶ Ra, ²³² Th, and ⁴⁰ K in soil from the gold artisanal mining and resident farming areas was 0.590. The calculations further indicate that the maximum morbidity ECR value is highest in 120 years. It shows that the highest ECR was from ²²⁶ Ra, and the highest exposure pathways were through direct radiation from soil (direct and airborne) and inhalation. The findings of this study could be helpful in determining the risk of environmental natural radioactivity as well as in making decisions about radiation protection.