Concentration and Annual Effective Dose of Radon in the Neyshabur Turquoise Mine

Background: Radon is one of the most common radioactive substances in underground mines which can enter the lungs and cause diseases. The purpose of this research is to measure the concentration of radon and the annual dose absorbed by miners at Sabz, Moslem, and Kamari caves in Neyshabur turquoise mine. The results are compared with standard permissible limits and can play a significant role in preventing risk of diseases in mone workers. Materials and Methods: The concentration of radon in the Neyshabur turquoise mine was measured at the depth of 250 m from the earth surface using the RTM1688 device. The obtained values were used to caculate the annual effective dose of radon absorbed by miners. Results: The results show that the concentration of radon was 5039.33, 678.46, and 3277 Bq.m-3  respectively at three locations of Sabz, Moslem, and Kamari caves with mean annual effective doses in miners as 41.07, 38.78 and 26. 70 mSv per year, respectively.  Conclusion: The measured concentration values are higher than  the maximum permissible limit in three locations of the Neyshabur turquoise mine, and the mean annual effective dose was higher than the permissible limit in Sabz and Moslem caves. In order to prevent morbidity, it is suggested that working time be reduced, miners’ unnecessary traffic be avoided in high-dose locations, and high-efficiency ventilation be used.