Determination of radiotoxic elements in non-alcoholic carbonated and functional drinks consumed in Türkiye and assessment of radiological health risks

The strategy to control the presence of radiotoxic elements or radionuclides in drinking water is based on the individual dose criterion of 100 mSv/y, which represents a very low risk level that is not expected to cause any defined adverse health effects. Some natural radionuclides, such as radon and radium isotopes (226Ra and 228Ra), can dissolve and accumulate in drinking water. Therefore, the radiological quality of drinking water is determined by the concentration of natural radionuclides dissolved in water. Carbonated (cola, fizzy, soda, tonic, fruit-flavored soda, etc.) and functional energy drinks, mainly contain drinking water, phosphoric acid, citric acid, caffeine, taurine, vitamin B, sweeteners, herbal extracts, energy-boosting ingredients, etc. represent the most consumed non-alcoholic (soft) drinks groups worldwide and in Türkiye. In this study, some physicochemical properties (pH, conductivity, total dissolved solids and Brix values) and radiological quality of 24 carbonated and 16 energy drink samples belonging to the most preferred commercial brand in Türkiye and radiological health risks caused by the consumption of these drinks were investigated. The average activity concentration of radon gas analyzed in soft drink samples using radon analyzer (AlphaGUARD) was found to be 0.0342 Bq/L for carbonated drinks and 0.0292 Bq/L for energy drinks. These values are incomparably lower than the upper limit recommended for drinking water in the European Union directive of 100 Bq/L. The average activity concentrations of radium isotopes analyzed in soft drink samples using a gamma-ray spectrometer with a high-purity germanium detector were found to be 0.45 Bq/L (226Ra), 0.72 Bq/L (228Ra) for carbonated drinks and 0.41 Bq/L (226Ra), 0.70 Bq/L (228Ra) for energy drinks. The activity concentrations of 228Ra analyzed in soft drink samples were higher than the guideline level of 0.1 Bq/L recommended for drinking water in the World Health Organization Guidelines, while the activity concentrations of 226Ra were lower than the guideline level of 1 Bq/L. The total annual effective radiation doses estimated to assess radiological health risks for adults were found to be 8.1 mSv/y for carbonated drinks and 0.3 mSv/y for energy drinks. These radiation dose values are below the individual dose of 100 mSv/y recommended for drinking water in the Turkish Regulation on Water Intended for Human Consumption.