²²² Rn and ²²⁰ Rn Levels in Drinking Water, the Related Health Implications, and Influencing Environmental Parameters in the Volcanic Area of Nkongsamba, Cameroon

Abstract

Radon ( 222 Rn) and thoron ( 220 Rn), both naturally occurring radioactive gases, are significant contributors to radiation exposure, posing risks such as lung and stomach cancer. This study assesses radon and thoron concentrations in drinking water sources within the volcanic region of Nkongsamba, Cameroon. It also evaluates their health implications and the environmental parameters affecting their distribution, with a focus on radon. Water samples from multiple drinking sources were analyzed at 16 sampling points, and radon and thoron levels were quantified using SARAD EQF3200 equipment. A comprehensive analysis was conducted to assess the related annual effective dose, the excess lifetime cancer risk, and environmental factors, namely, temperature, atmospheric pressure, relative humidity, and altitude, that may influence the concentration of these gases in water. The data revealed that radon concentrations were compliant with WHO guidelines, and 25% of the obtained data displayed radon concentrations higher than the 11 Bq/L limit suggested by the United States Environmental Protection Agency (US EPA). However, thoron levels exhibited significant variability and were less correlated with environmental conditions, attributed to their relatively short half‐life. The analysis of environmental parameters indicates that correlations are weak, suggesting that the concentration of radon in water is influenced to some extent by physical equilibrium conditions. Among the assessed factors, temperature and pressure emerge as the most significant variables impacting radon levels. These findings highlight the necessity for ongoing monitoring and the implementation of mitigation strategies to alleviate potential health risks associated with radioactive gas exposure. The study establishes a critical baseline for future research and informs public health policies in the region.