Assessment of Radioactivity Concentrations and Associated Radiological Health Risk in Natural Spring Mineral Bottled Drinking Water from South Africa

Naturally occurring radionuclides are ubiquitous at various levels of concentration, while exposure to ionizing radiation by humans is of global concern. Radiological health risk assessment due to the consumption of natural spring mineral water is critical for ensuring public health and safety. This study aims at investigating the radioactivity concentration levels of natural radionuclides 226Ra, 232Th and 40K and the associated radiological health risk in commercial natural spring bottled water in South Africa. A total of 21 of the most-consumed bottled drinking water brands from grocery stores, were analysed using the HPGe gamma detector. The results indicate that the range of radioactivity concentrations is from 1.060 ± 0.067 to 2.571 ± 0.143 BqL−1, with a mean of 1.766 ± 0.399 BqL−1 for 226Ra; 1.736 ± 0.112 to 7.807 ± 0.099 BqL−1, with a mean of 3.688 ± 1.371 BqL−1 for 232Th and 149.000 ± 38.480 to 242.900 ± 59.700 BqL−1 with a mean of 220.229 ± 22.297 BqL−1 for 40K. The potential radiological health risks evaluated show mean values for Raeq, DAb, AEID and AGED as 23.976 ± 0.446 BqL−1, 12.232 ± 1.445 nGyh−1, 0.060 ± 0.007 mSvy−1 and 0.090 ± 0.027 mSvy−1, respectively. The radiation dose based on age group is in the order of infants (≤1 year) > teenagers (12–17 years) > children (1–12 years) > adults (>17 years). The activity concentrations of radionuclides in bottled water are ranked in the order of 40K > 232Th > 226Ra, with 232Th contributing the highest radiation dose, consistent with findings reported in previous studies. The findings reveal that the activity concentration levels and estimated radiological health risks are within the permissible limits set by UNSCEAR guidelines. Therefore, the consumption of bottled water is radiologically safe. However, the findings also suggest that 12 out of 1000 individuals may suffer cancer fatality, while 6 out of 1 million individuals may experience hereditary effects over their lifetime from the consumption of bottled water. Regular monitoring and stringent regulatory controls are recommended to ensure the radiological safety of bottled drinking water in South Africa.