Estimation of Annual Effective Dose and Excess Lifetime Cancer Risk due to Natural Gamma Near Hot Water Spring

Many people believe that hot water springs are effective in treating many skin diseases, but they are unaware of the presence of natural radioactive substances that may be found in these springs. Radioactive substances with different ray emission can increase the dose rate of people and risk of cancer. The aim of this study is to estimate the annual effective dose and excess lifetime cancer risk (ELCR) due to natural gamma near Garab hot water spring in Behbahan city.
Subjects and To measure of gamma dose rate in the hot water spring and around it, six points were considered. The dose rate in these areas was measured using the RDS-31 Survey meter in four seasons of the year. Also the dosimeter was placed at two heights of 5 cm and 1 m, and the dose rate was read and recorded for 10 minutes in any point. The maximum and minimum amount of absorbed dose rate was obtained in Summer and Winter 392 nGy/h and 42 nGy/h, respectively. The annual effective dose at point 1 (nearby the principle hot water source) was calculated 0.4 mSv. The excess lifetime cancer risk was gained at this point with the highest value of 1.60×10-3. The results of this study showed that the annual effective dose and excess lifetime cancer risk of natural gamma in the hot water spring is higher than the global average but, these values are lower than the standard for residents of the Garab village