Radon Gas Risk Indices in Water on Fractured Basement of Ayetoro Housing Scheme, Oyo

Radon gas, a naturally occurring radioactive element, presents significant health risks, particularly in areas with fractured basement geology, where subsurface characteristics can elevate its concentration. As the second leading cause of lung cancer globally, after smoking, radon exposure is a critical public health concern. This study seeks to evaluate the concentration levels of radon gas, analyze its potential health risks to the residents, and provide insights into the environmental factors influencing radon accumulation in this area. Thirty (30) samples were collected for groundwater from various locations within the study area. Groundwater samples were collected from selected drinking water sources using 1.5 litre plastic bottles. Radon gas concentration was measured using a RAD7 electronic radon detector for soil and RAD7 H2O for groundwater. The data obtained was analysed using a statistical tool to perform a one-way Analysis of Variance (ANOVA). The samples were also subjected to decay corrections to ensure the accuracy of the results. The data were analysed using descriptive and inferential statistics, with statistical significance set at p<0.05. Groundwater radon concentrations ranged from 0.576Bq/L to 6.54Bq/L with a mean concentration value of 2.81 Bq/L and a standard deviation of 1.73 Bq/L. The mean annual effective dose for radon due to inhalation, ingestion and whole- body are 0.0254 mSvy^(-1), 0.00987 mSvy^(-1) and 0.0352 mSvy^(-1) respectively. The results were all below the recommended threshold of 0.1 mSvy^(-1) set by the World Health Organization (WHO). The Excess Lifetime Cancer Risk (ELCR) value of 12.34 × 10^(-5) was obtained which corresponds to about 1.23 in 10,000 risk of developing cancer over a lifetime due to radon exposure through water. The study on radon concentration in groundwater from the Ayetoro Housing Scheme, Oyo, found an average radon level of 2.82 Bq/L, below the EPA's maximum contaminant level (MCL) of 11.1 Bq/L. This indicates that residents in the area are not at significant risk from radon exposure at the time of the study. However, it was observed that inhalation of radon from water presents a higher radiological hazard than ingestion. The study recommends regular radon monitoring in the area to ensure continued safety