Natural Gamma Radiation and Effective Annual Dose in Hot Springs in South Khorasan Province, Iran

Background and purpose:  Background radiation exists naturally in the environment and human has been always exposed to it. These rays can affect living creatures and cause chromosomal damage, and genetic and somatic diseases. Hot water springs are a major source of background radiation. This study aimed at investigating the absorbed dose of environmental gamma and determining the annual effective dose of hot water springs in South Khorasan province, Iran, during summer and autumn of 2018. Materials and methods: In order to measure the peripheral gamma of hot springs, the X5C PLUS dosimeter was used. Dosimetry was performed for all outdoor and indoor hot springs in two seasons (summer and autumn). The data for gamma irradiation were calculated and reported as nano-sievert per hour and annual effective dose in milli-sievert per year. Data analysis was done in Excel and SPSS applying ANOVA. Results: In current study, the highest and lowest mean gamma radiation were found in Dig Rostam and Tabas hot springs, respectively. The mean effective dose in all outdoor hot springs was significantly lower than that in indoor hot springs (P <0.001). Conclusion: The average gamma background radiation and the annual effective dose was lower than international standards in all outdoor hot springs, but in Ferdos and Sarbisheh hot springs (indoor) the mean values were higher than the standards which could be a threat for their customers and staff.