Determination of natural thorium isotopes (230Th and 232Th) in calcium and magnesium supplements and the potential effective exposure radiation dose for human

Abstract The article presents a study on the content of radiotoxic thorium radionuclides, alpha-emitting 230Th and 232Th, as a possible additional source of these radioisotopes in the human diet in the most popular calcium and magnesium supplements available for adults in Poland. It was also examined whether the supplements impact the value of effective radiation doses to the consumers. The analyzed pharmaceuticals contained different organic or inorganic calcium or magnesium compounds, and some of them were of natural origin, while most of the organic compounds were synthetic. Based on the study, the 230Th concentrations in natural origin calcium and magnesium supplements were significantly higher than in synthetic. The results showed that the highest value of 230Th activity was found in natural origin pills produced from chalk and equalled 6.20 ± 0.17 m Bq/g, while the highest 232Th activity concentration was determined in the dolomite sample and determined at 0.58 ± 0.05 m Bq/g. The evaluation showed that calcium and magnesium supplements could contribute to an annual effective radiation dose of less than 3 µSv, but the amount is much than the annual radiation dose from 230Th and 232Th decay ingested with daily food (0.3 µSv). For this reason, the consumption of these supplements may increase the annual effective radiation dose received by a human. Notwithstanding, the exposure is considered low from the radiological and toxicological points of view.