Radon gas, the predominant source of natural occurring radioactive substances is released by natural decay of uranium in the ground. Its half-life is 3.823 days and it can penetrate soils and rocks, contaminating surface and ground water sources. Ingestion (oral) and inhalation leads to a build-up of its daughters 218Po and 214Po in the lungs, whose high-energy alpha and gamma radiation damage cells. This research work aimed to evaluate the health hazards associated with 222Rn in some selected drinking water sources from Jibia Town, Katsina State, Nigeria. Twenty water samples from three different water sources were analyzed using liquid scintillation counter (Model Tri-Carb-LSA1000) situated at the Centre for Energy Research and Training of ABU Zaria. The corresponding annual effective doses due to ingestion and inhalation of 222Rn were also estimated. The mean activities concentrations of radon for surface, well and borehole water sources were 1.800.01BqL-1, 5.990.02 BqL-1 and 7.970.04 BqL-1 respectively, with overall mean value of 5.210.03 Bq/L. Similarly, the estimated mean annual effective dose due to inhalation and ingestion of radon were13.140.9 µSv/y (for all ages) and 37.952.5 µSv/y, 57.083.8 µSv/y and 66.594.4 µSv/y for adults, children and infants, respectively. Based on the achieved results, the specific activity concentrations of the radon and the estimated annual effective doses due to ingestion and inhalation of 222Rn were all found to be below the World average value of 10Bq/L set by WHO (2011) and recommended limit of 100µSv/y set by WHO (2011), respectively. Hence the radon concentrations were found to pose non-significant hazard to the populace from the drinking water sources.

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