Exposure to 222Rn in ten underground mines in Iran

Concentrations of 222Rn were measured in ten non-uranium underground mines in Iran, including three metal mines and seven coal mines. Two active techniques were applied for these measurements (1) activated charcoal and (2) scintillation cell. A maximum mean concentration of 1.33 kBq.m-3 was found in the Robat-Karim manganese mine with a hot spot of 12 kBq.m-3, while the concentration in the Venarge-Qom manganese mine was less than 10 Bq.m-3, leading to annual effective dose equivalents of 8.3 mSv and 0.06 mSv respectively. The mean concentration levels of 222Rn in coal mines were found to be almost 500 Bq.m-3, leading to annual effective dose equivalent of 3 mSv. (author)