Radiological risk assessment in drinking water: evaluation of radon concentrations in Ondo town, southwestern Nigeria

Radon exposure is a significant public health risk, accounting for 3-14% of all lung cancer cases. Radon exposure is the second biggest cause of lung cancer in smokers and the first among nonsmokers. This study evaluates radon concentrations and assesses the annual effective doses of radon via ingestion and inhalation in drinking water sources in Ondo town. For this purpose, forty samples of groundwater used for drinking were analyzed for radon concentration using RAD7 alpha spectrometry. Activity concentrations of radon in Ondo town ranges from 0.41 to 5.57 Bql-1 with an average value of 1.94 Bql-1 . The mean concentration of radon is -1 substantially lower than the United State Environmental Protection Agency suggested limit of 11.1 Bql-1 . The annually effective dosage for ingestion for infants (10.28 µSvy ), children (3.78 µSvy ) and adults (4.96 µSvy ) and inhalation (0.005 µSvy ) were below the action level value of 0.1 mSvy suggested by World Health -1 Organization and 3-10 mSvy proposed by the International Commission on Radiological Protection (ICRP). The data and results from this study could serve as a guide for future policies guiding the development, operation, and preservation of groundwater resources in the investigated region.