Department of Global Health, Medical and Welfare, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
PLoS One. 2012;7(9):e45816. doi: 10.1371/journal.pone.0045816. Epub 2012 Sep 26.
To evaluate the environmental contamination and radiation exposure dose rates due to artificial radionuclides in Kawauchi Village, Fukushima Prefecture, the restricted area within a 30-km radius from the Fukushima Dai-ichi Nuclear Power Plant (FNPP), the concentrations of artificial radionuclides in soil samples, tree needles, and mushrooms were analyzed by gamma spectrometry. Nine months have passed since samples were collected on December 19 and 20, 2011, 9 months after the FNPP accident, and the prevalent dose-forming artificial radionuclides from all samples were (134)Cs and (137)Cs. The estimated external effective doses from soil samples were 0.42-7.2 µSv/h (3.7-63.0 mSv/y) within the 20-km radius from FNPP and 0.0011-0.38 µSv/h (0.010-3.3 mSv/y) within the 20-30 km radius from FNPP. The present study revealed that current levels are sufficiently decreasing in Kawauchi Village, especially in areas within the 20- to 30-km radius from FNPP. Thus, residents may return their homes with long-term follow-up of the environmental monitoring and countermeasures such as decontamination and restrictions of the intake of foods for reducing unnecessary exposure. The case of Kawauchi Village will be the first model for the return to residents' homes after the FNPP accident.
为了评估福岛县川内村因人工放射性核素造成的环境污染和辐射暴露剂量率，在距离福岛第一核电站（FNPP）30 公里半径的限制区内，通过伽马能谱分析了土壤样本、树枝和蘑菇中的人工放射性核素浓度。在 FNPP 事故发生 9 个月后，即 2011 年 12 月 19 日和 20 日采集了样本，9 个月过去了。所有样本中主要的放射性核素是（134）Cs 和（137）Cs。在距离 FNPP 20 公里范围内，土壤样本的估算外照射有效剂量为 0.42-7.2 μSv/h（3.7-63.0 mSv/y），在距离 FNPP 20-30 公里范围内，土壤样本的估算外照射有效剂量为 0.0011-0.38 μSv/h（0.010-3.3 mSv/y）。本研究表明，目前川内村的放射性水平正在显著降低，特别是在距离 FNPP 20-30 公里范围内。因此，居民可以在长期环境监测和去污以及限制摄入食物等措施的基础上返回家园，以减少不必要的辐射暴露。川内村的情况将成为 FNPP 事故后居民返回家园的首个范例。
