This study assesses the concentration of Radon-222 in drinkable groundwater and surface water samples across the 14 local government areas of Zamfara State, Nigeria, to evaluate potential radiological health risks. A total of 56 water samples (well and river water) were analyzed using a Liquid Scintillation Counter (LSC) at the Center for Energy Research and Training (CERT). The results revealed mean radon concentrations of 634.11Bq/m3 for river water and 453.23 Bq/m3 for well water. While these values remain below the USEPA maximum contaminant level of 11,100 Bq/m3, they significantly exceed global averages for natural surface and groundwater. Radiological hazard indices were calculated, showing mean annual effective doses by inhalation of 27.90 mSv/y and 19.94 mSv/y for river and well water, respectively. These values exceed the ICRP annual public exposure limit of 1 mSv/y, indicating that inhalation of degassed radon during domestic use poses a more substantial risk than direct ingestion. The mean Excess Lifetime Cancer Risk (ELCR) was estimated at 1.62 x 10-5 for river water and 1.16 x 10-5 for well water, falling within the acceptable international range 10-6 to 10-4. The elevated radon levels are attributed to the state's uranium-rich geological formations and artisanal mining activities. The study concludes that while the immediate cancer risk is within acceptable limits, the high inhalation exposure warrants implementing aeration and water treatment strategies to safeguard public health in the region.
Nasir et al. (Sat,) studied this question.