Assessment of Radiation Dose from the Consumption of Bottled Drinking Water in Japan.

Activity concentrations of ²³⁴ U, ²³⁵ U, ²³⁸ U, ²²⁶ Ra, ²²⁸ Ra, ²²² Rn, ²¹⁰ Po, ²¹⁰ Pb, ⁴⁰ K, ³ H, ¹⁴ C, ¹³⁴ Cs and ¹³⁷ Cs were determined in 20 different Japanese bottled drinking water commercially available in Japan. The origins of the mineral water samples were geographically distributed across different regions of Japan. Activity concentrations above detection limits were measured for the radionuclides ²³⁴ U, ²³⁵ U, ²³⁸ U, ²²⁶ Ra, ²²⁸ Ra and ²¹⁰ Po. An average total annual effective dose due to ingestion was estimated for adults, based on the average annual volume of bottled water consumed in Japan in 2019, reported to be 31.7 L/y per capita. The estimated dose was found to be below the recommended World Health Organisation (WHO) guidance level of 0.1 mSv/y for drinking water quality. The most significant contributor to the estimated dose was ²²⁸ Ra.