Determination of activity concentration of radon gas contained in commercially sold bottled natural spring waters in Turkey and evaluation of radon-induced radiological risk

Bottled spring water obtained from underground waters is increasingly consumed in Turkey due to the faith in the safer than tap waters supplied from municipal water sources. Radon, which occurs in the natural uranium series, is a colorless, odorless, and radioactive gas. Radon gas in soil and rock can move into underground water sources and dissolve in water. The variation of dissolved radon levels in water supplies remains of interest since radon ingested through drinking water can give considerable radiation to the lining of the stomach. This study aims to determine the radon levels of commercially sold and consumed bottled spring waters in Turkey and to evaluate the internal exposure caused by the ingestion of these waters and inhalation of air containing degassed radon from the waters. For this aim, the activity concentration of radon in bottled spring water samples belonging to the eighty-three most consumed brands in Turkey was measured using a radon gas monitor (Alpha GUARD PQ 2000PRO). The activity concentrations of radon measured in bottled spring water samples varied from 3.20.8 to 28.72,7 mBq/L with an average of 14.8±0.6 mBq/L. The radon level measured in the investigated bottled spring water samples is well below the maximum radon levels of 100 Bq/L and 11.1 Bq/L for drinking water recommended by the European Commission (EC) and the United States of America Environmental Protection Agency, respectively. The total annual effective radiation dose (TAERD) caused by the ingestion and inhalation of radon in bottled spring water samples was estimated to evaluate internal irradiation for three age groups (infants, children, and adults) in four different scenarios based on annual drinking water consumption. Also, the excess lifetime time cancer risk (ELTCR) associated with TAERD was calculated for adults. The values of TAERD are significantly lower than 100 μSv, which is the individual dose criterion determined in the EC directive on waters and the drinking water regulation prepared by the Ministry of Health. Therefore, the results obtained in the study revealed that the consumption of the investigated bottled spring water samples did not pose a significant radiological health risk for the Turkish people.