Age-specific assessment of annual effective dose and excess lifetime cancer risk from radon in tap water of Mueang Ubon Ratchathani, Thailand.

The purpose of this study is to evaluate the level of radon in tap water and its associated health impacts in Mueang District, Ubon Ratchathani Province, Thailand. The condition focuses on the annual effective dose (AED), excess lifetime cancer risk (ELCR), and lung cancer cases per year per million persons (LCC) in different age groups, including infants (0-1 year old), children (2-17 years old), and adults (above 17 years old). A total of 27 samples is collected from different areas of Ubon Ratchathani, and the measurement is done with the RAD7 radon detector and accessories of RAD H2O. The average radon level in tap water in Ubon Ratchathani is at 0.40 ± 0.09 Bq/L, which is quite lower as compared to the guideline value suggested by the United States Environmental Protection Agency (US EPA). It should be noted that the measured values are close to the detection limit of the RAD7 & H2O system, and the uncertainty at such low concentrations is relatively high. The annual effective dose, excess lifetime cancer risks, and lung cancer cases per year per million persons vary among each age group. Infants have the highest average annual effective dose, followed by adults and children, of 2.13 ± 0.48 μSv/y, 0.78 ± 0.18 μSv/y, and 1.03 ± 0.23 μSv/y, respectively. A similar trend is also found in excess lifetime cancer risk and lung cancer cases per year per million persons. This finding shows that the radon level in the tap water in the area of study is lower than the level recommended by the World Health Organization (WHO); however, continuous monitoring is required to prevent health risks for the population.