Age-dependent Radiological Risk Assessment of Radon (222Rn) in Samples of Commercial Bottled Water from Benin City, Nigeria

Radon inhalation as well as ingestion through the use of water has a high potential of causing serious harm to sensitive cells and organs of the body when absorbed into the bloodstream. Therefore, this study aimed to assess the radiological health damage caused by radon in drinking bottled water available in Benin City, Edo State, Nigeria. Radon concentration was measured using a RAD7 electronic radon detector. The mean activity concentration radon is 137.18 ± 0.25 mBq/L. This mean value is slightly higher than 0.1 Bq/L recommended by the Standard Organisation of Nigeria but lower than the maximum contaminant level (MCL) of 11.1 Bq/L set by the United States Environmental Protection Agency and 100 Bq/L set by the World Health Organisation (WHO) for consumption of radon in drinking water. The mean total annual effective dose is 1.07±1.91 (Sv/y) for infants, 0.61±1.09 (Sv/y) for children, and 0.70±1.24 (Sv/y) for adults. The computed annual effective dose to the public by inhalation and ingestion radon through the use of bottled water in the study areas are lower than the 0.1 mSv/y limit recommended by WHO. The estimated average for the age group excess lifetime cancer risk are 3.21 ± 5.71, 1.836 ± 3.26, 2.086 ± 3.71 (x 10-6) for infants, children and adults respectively. These values are below the world average permissible levels. Hence, consumption of the water examined poses no serious health risk to consumers.