Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8527, Japan.
Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan.
Environ Pollut. 2018 Mar;234:1-8. doi: 10.1016/j.envpol.2017.11.018. Epub 2017 Nov 17.
The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident on March 11, 2011, caused severe radioactive contamination in Fukushima Prefecture. In order to clarify the safety of drinking water, we have conducted radiocesium monitoring of public tap water and groundwater in Minami-Soma City, which is 10-40 km north of the nuclear power plant. The source of tap water for Minami-Soma City is groundwater, which is treated by rapid filtration before distribution in two of the three treatment plants. The tap water was collected from six stations during 2012-2016 and groundwater was collected from 11 stations with wells between 5 and 100 m deep during 2014-2016. Radiocesium contamination of groundwater has been considered unlikely in Japan because of the small vertical migration velocity of radiocesium in Japanese soil. However, radiocesium was detected in public tap water after 2012, and the maximum Cs concentration of 292 mBq L was observed in 2013. In all the well water, radiocesium was detected between 2014 and 2015, at concentrations similar to those observed in tap water in the same period. In tap water and groundwater, radiocesium was decreased to below the detection limit in 2016 except for four stations. Radiocesium concentration in shallow water reached a maximum between 2013 and 2015, 2-4 years after the FDNPP accident, and then decreased. The results are interpreted that dissolved Cs migrated in the soil and reached aquifers of various depth.
2011 年 3 月 11 日福岛第一核电站（FDNPP）事故导致福岛县遭受严重放射性污染。为了明确饮用水的安全性，我们对位于核电站以北 10-40 公里的南相马市的公共自来水和地下水进行了放射性铯监测。南相马市的自来水水源是地下水，在三个处理厂中的两个处理厂中，在分配之前经过快速过滤处理。2012-2016 年期间从六个站点采集自来水，2014-2016 年期间从 11 个井深 5-100 米的站点采集地下水。由于日本土壤中放射性铯的垂直迁移速度较小，因此在日本地下水受到放射性铯污染的可能性较小。但是，自 2012 年以来已经在公共自来水中检测到放射性铯，并且在 2013 年观察到最大 Cs 浓度为 292 mBq L。在所有井水（2014-2015 年）中，都检测到放射性铯，其浓度与同期自来水相似。除了四个站点外，2016 年自来水中和地下水中的放射性铯都降低到检测限以下。浅层水中的放射性铯浓度在 2013 年至 2015 年之间达到最大值，即 FDNPP 事故发生后的 2-4 年，然后下降。结果表明，溶解的 Cs 在土壤中迁移并到达各种深度的含水层。
