Correlation between radon and radium concentrations in soil and estimation of natural radiation hazards in Namom district, Songkhla province (Southern Thailand)

Abstract

The purpose of this work was to investigate the correlation between concentrations of radon (222Rn) and radium (226Ra) in soil and to estimate the potential natural radiation hazard indices in Southern Thailand, Songkhla province, Namom district. In this study, the concentration of radon was measured by RTM1688-2 radon monitor and radium content was made using a high-resolution gamma spectrometer. A positive correlation coefficient between exhaled radon in soil gas and radium concentrations has been observed. Average concentrations of 226Ra, 232Th and 40K in soil samples were (108 ± 26), (114 ± 22) and (1081 ± 278) Bq kg−1, respectively. These values were used to estimate the radiological health hazard indices using standard analytical methods. The estimated absorbed dose rate, annual effective dose equivalent, gamma radiation hazard index and excess lifetime cancer risk are higher than world permissible limit. These values show a significant health risk due to radiation pollution in Southern Thailand.