Kardan M R, Fathabdi N, Attarilar A, Esmaeili-Gheshlaghi M T, Karimi M, Najafi A, Hosseini S S
Reactor and Nuclear Safety Research School, Nuclear Science and Technology Research Institute, Tehran, Iran.
Iran Nuclear Regulatory Authority, Tehran, Iran.
J Environ Radioact. 2017 Nov;178-179:168-176. doi: 10.1016/j.jenvrad.2017.08.010. Epub 2017 Aug 29.
In the past, some efforts have been made for measuring natural radioactivity and evaluating public exposure to natural radiation in certain areas of Iran especially in well-known High Level Natural Radiation Areas (HLNRA) in Ramsar and Mahallat. However, the information on radionuclide concentrations, and, consequently, terrestrial radiation exposure for many other areas are not available. There was therefore a need for a systematic and nation-wide survey. For this purpose, 979 soil samples from 31 provinces were collected. The activity concentrations of K, Ra and Th were measured by HPGe detector. The average activity concentrations for Iran were found to be 457.7 Bq/kg for K, 24.3 Bq/kg for Ra and 25.8 Bq/kg for Th. Results were compared with previous regional or provincial surveys. The population-weighted average outdoor and indoor annual effective dose due to external exposure to terrestrial sources of radiation are 0.06 mSv and 0.33 mSv, respectively. It was shown that there is a significant correlation between the activity concentrations of Th and K in soil. In addition, the results of chi square tests show normal and lognormal distributions cannot be considered for the frequency distributions of activity concentration of Th and Ra while K has a normal distribution.
过去，伊朗在某些地区，尤其是拉姆萨尔和马哈拉特著名的高本底天然辐射区（HLNRA），已开展了一些测量天然放射性和评估公众天然辐射暴露的工作。然而，许多其他地区的放射性核素浓度信息以及陆地辐射暴露情况尚无数据。因此，有必要进行系统的全国性调查。为此，从31个省份采集了979份土壤样本。用高纯锗探测器测量了钾、镭和钍的活度浓度。伊朗钾、镭和钍的平均活度浓度分别为457.7 Bq/kg、24.3 Bq/kg和25.8 Bq/kg。将结果与之前的区域或省级调查进行了比较。陆地辐射源外照射导致的人口加权平均室外和室内年有效剂量分别为0.06 mSv和0.33 mSv。结果表明，土壤中钍和钾的活度浓度之间存在显著相关性。此外，卡方检验结果表明，钍和镭活度浓度的频率分布不能视为正态分布和对数正态分布，而钾具有正态分布。
