Initial Evaluation of Exposure of Adult Residents in Dange-Shuni Local Government Area to Radioactive Cesium (Cs-137) through Ingestion

Radioactive Cesium (137-Cs) is widely used in hospitals as a gamma source for calibrating medical radiotherapy devices used in cancer treatment. It is also employed to calibrate radiation detection instruments. However, radioactive cesium-137 is one of the most concerning contaminants in water, as it emits both gamma and beta radiation, has a physical half-life of approximately 30 years, and a biological half-life of about 70 days. This work, therefore, aimed at assessing the radioactivity concentration of Cs-137 in the groundwater of the whole Dange-Shuni Local Government Area (LGA) using a High purity germanium (HPGe) detector. This will assist in confirming the annual effective dose and, thus, the lifetime cancer risk that Cs-137 can impose on the inhabitants of this environment. Stratified Random Sampling was used in sampling the water for the analysis to ensure adequate representation of possible different geological structures that exist in the study area. The activity concentration of Cs-137 was within the range of 4.65 ± 0.24 Bq.L-1 to 96.42 ± 4.95 Bq.L-1, with an average value of 13.72 BqL-1. The activity concentration was found to be higher at Majia, whereas the lowest value was reported at Kalausar dutsi. The annual effective dose was estimated to be from 2.41 to 49.90 mSvy-1 with a mean value of 7.09 mSvy-1. With 2.17 x 10-3, Majia had the greatest risk cancer mortality rating, while Kalausar Dutsi had the lowest, at 1.05 x 10-4. Also, morbidity risk was found to be highest at Majia with a value of 3.15 x 10-3 and lowest at Kalausar Dutsi with a value of 1.52 x 10-4. The notably high activity level observed in this study suggests that fractures in the granitic layers of the subsurface geology may have formed, leading to the extensive distribution of radiation doses in the area. Water softeners in the form of ion exchange can be applied to reduce the percentage of radionuclides in the drinking water of this environment.