A survey of 222Rn concentrations in domestic water supplies of Iran.

As part of a national program to determine public exposure to natural radiation, 222Rn concentrations were determined in domestic water supplies, including ground and surface waters, in 23 provincial centers using a liquid scintillation counting technique. The minimum and maximum mean concentrations of 222Rn in ground water were, respectively, 7.9+/-4.5 kBq m(-3) in Sanandaj and 46.5+/-11.5 kBq m(-3) in Tehran with an overall national mean value of 21+/-8.3 kBq m(-3). The 222Rn concentrations in surface waters ranged from less than 1 to 7 kBq m(-3) with a mean value of 3.9+/-1.9 kBq m(-3). The mean concentration of 222Rn in tap water in different parts of Tehran is 3.8+/-1.1 kBq m(-3). The results are presented and discussed in this paper.