Annual Effective Dose Analysis and Radiological Effects of Rn-222 in Southern Benue Groundwater Sources

Health risks and annual effective dose of radon (Rn-222) concentration have been evaluated in drinking water samples collected from various locations of Okpokwu and Ogbadibo Local Government Areas of Benue South, Nigeria. The radon distribution in water samples was performed using a calibrated Liquid Scintillation Counter (LSC–Tricarb–1000). The mean values for underground water samples in the study locations were higher than the threshold value of 11.1 Bq/l set by the United States Environmental Protection Agency but below the 100 Bq/l reference level set by the World Health Organization and the European Commission. Annual effective dose (AED) was estimated for different age groups (Adults, Children, and Infants) based on the average annual water consumption rates. The annual effective dose received by infants in underground and surface water samples was higher comparatively to that of adults and children due to the radio sensitivity of the infants despite the higher water consumption rates by adults and children. The excess lifetime cancer risks (ELCR) for adults, children, and infants were below the allowable maximum concentration of 0.29 mSv/y for drinking water proposed by the United Nations Scientific Committee on Effects of Atomic Radiations (UNSCEAR). The AED to the lungs due to inhalation is higher than the dose to the stomach due to radon ingestion suggestive of possible lung cancer than gastrointestinal cancer.