Health risk assessment of radon exposure through drinking water in Iluagba, Kogi State, Nigeria

This study investigates radon concentrations in groundwater from 20 locations in Iluagba, Kogi State, Nigeria, analyzed using a liquid scintillation counter. Radon levels ranged from 10.6-43.1 Bq/L (average 24.1 Bq/L). Although below the World Health Organisation (WHO) limit of 100 Bq/L, about 90 % exceeded the United States Environmental Protection Agency (USEPA) advisory level of 11.1 Bq/L, indicating potential long-term health risks. The annual effective dose (AED) was highest in infants (up to 163.5 µSv/y), with seven samples exceeding the WHO reference dose of 100 µSv/y. Excess lifetime cancer risk (ELCR) values for all age groups surpassed the USEPA safety threshold (1.0 × 10^-⁴), identifying infants as the most vulnerable group. Organ-specific analysis showed the lungs received substantially higher doses than the stomach, confirming inhalation as the primary exposure route. While strong correlations (r ≈ 1.0) validated internal data consistency, the elevated radiological risk remains the key concern. Compared with other Nigerian regions, Iluagba exhibits moderate to high exposure levels. These findings underscore the need for targeted radon mitigation, community education, and routine groundwater monitoring to safeguard public health in Kogi State.