Health risk assessment of uranium intake from private residential drinking groundwater facilities based on geological characteristics across the Republic of Korea

Groundwater contributes to an average of 8 % of the total water source capacity in the Republic of Korea. Hence, private residential households in rural areas in Korea are still using groundwater for drinking without any regular water quality inspection. This can increase the risk of exposure to natural radionuclides like uranium through drinking groundwater. This study investigated the uranium level in drinking groundwater all over the country by analyzing 11,451 samples from private residential drinking groundwater facilities and compared the exposure amount and its associated carcinogenic and non-carcinogenic risk based on the geological characteristics of the aquifer. Results yield that although the average hazard quotient (HQ) and excess cancer risk (ECR) of exposure to natural uranium through drinking groundwater were respectively below 1 and 1 × 10−6 and do not indicate a potential health hazard, significantly high HQ and ECR up to respectively 70 and 4 × 10−4 in samples where the aquifer is the Jurassic granite observed. Accordingly, regular water quality investigation and onsite treatment methods are required to provide healthy drinking water in such areas. [Display omitted] •Natural uranium level in nationwide private drinking groundwater facilities was analyzed.•Over 11,000 samples were taken from aquifers with different geological characteristics.•Natural uranium exposure and its potential health risks were assessed.•A high potential health risk is assessed where the aquifer is the Jurassic granite.•Regular water quality investigation and onsite treatment methods are recommended.