Determination of Rn- 222 concentration and annual effective dose of inhalation in the vicinity of hot springs in Kerman province, southeastern Iran

Background: Human exposure to Radon-222 gas is one of the most important natural radiation sources of radioactive gases, and inhalation of this gas and its decay products can cause lung cancer. Therefore, this study was conducted to measure Rn-222 concentration and determine annual effective dose of radon inhalation in the vicinity of hot springs in Kerman province, southeastern Iran. Materials and Methods: This study was carried out on 16 hot springs of Kerman province. Concentration of Rn-222 was measured using RAD-7 electronic system. Also, annual effective dose amounts of inhalation were estimated according to the formula provided by UNSCEAR (2000). Results: Minimum and maximum amounts of Rn-222 concentration in the samples were equal to 0.158±0.129 and 56.100±5.680 Bql-1, respectively. Annual effective dose amounts of inhalation were determined between 0.000±0.000 to 0.177±0.017 mSvy-1. Concentration of radon was more than 11 Bql-1 (the safe limit set by the EPA) in 5 samples collected from hot springs. Annual effective dose of inhalation of radon was more than 0.1 mSvy-1 (the safe limit set by the WHO) in Jooshan hot spring. Conclusion: By comparing concentration amounts of the samples with the EPA safe limit, it was concluded that, 11 hot springs were safe. Also, annual effective dose amounts of inhalation of all hot springs, except one of them were lower than the safe limit set by WHO.