Annual Effective Dose Estimation due to Gross Alpha and Beta Activities in Nigerian Bottled Drinking Water

Abstract

Background: Extremely humid, hot and dry climatic conditions of Nigeria has led to an increasing demand for clear and clean portable water supply across the nation. Additionally, the dehydrating traffic situations commonly witnessed in virtually all the major cities in Nigeria has made consumption of bottled water indispensable component of modern life in Nigeria. It is therefore important that the radiological burden incurred by the Nigerian population from ingestion of bottled water be investigated. Materials and Method: Twenty one brands of commercial bottled water regularly consumed in Nigeria were obtained from standard supermarkets and investigated for their gross alpha and gross beta radioactivity. This analysis, as a recommended first step in radio analytical screening, was performed using a gas-free, low background dual phosphor proportional counter. Results: Results of the analysis showed that mean values for gross alpha and gross beta activity concentrations in all the investigated bottled water samples were 15.22±0.93 mBq l-1 and 39.69±1.83 mBq l-1 respectively. These values were below safety limits recommended by the World Health organization. Computed average annual effective dose equivalent for adults, children and infants (lactating age) in Nigeria due to consumption of commercial bottled water were lower than the recommended safeguard of 0.1 mSv for drinking water. Conclusion: The results does not suggest any radiological threat to the health of consumers. However, intermittent monitoring of commercially consumed bottled water is recommended for water quality compliance from radiation safety perspective.