Drinking potable water is essential for ensuring public health safety. In Ogwashi-Uku, borehole water is becoming the main drinking water source due to inadequate piped borne water infrastructure. This study examines the natural radioactivity levels and radiological health risks in 26 borehole water samples collected from Ogwashi-Uku, Delta State, Nigeria. Results revealed that the concentrations of radium-226 ( 226 Ra) ranged between 2.4 and 9.4 Bq/L, thorium-232 ( 232 Th) ranged between 1.9 and 8.8 Bq/L and potassium-40 ( 40 K) ranged between 4.9 and 12.5 Bq/L. Annual effective dose (AED) recorded from ingestion varied from 0.46 to 1.84 mSv/yr with a mean of 0.97 mSv/yr for adults, 0.30 to 1.17 mSv/yr with a mean of 0.62 mSv/yr for children, and 1.54 to 6.66 mSv/yr with a mean of 3.40 mSv/yr for infants. These values exceed the World Health Organization (WHO) individual reference limit of 0.1 mSv/yr, indicating an elevated radionuclide exposure that requires close attention. The calculated average lifetime radiological toxicity risk (RTR) across the study area revealed a mean mortality risk of 9.31 × 10 - 4 and a mean morbidity risk of 1.40 × 10 - 3 higher than the acceptable lifetime cancer risk threshold ( 10 - 4 to 10 - 5 ) set by the WHO and USEPA. The findings demonstrate that the continuous consumption of untreated borehole water in Ogwashi-Uku has the potential to expose consumers to levels of radiological hazards that may be considered unacceptable. Therefore, periodic monitoring and mitigation measures are recommended.
Faraj et al. (Fri,) studied this question.