Graduate School of Science , Osaka University , 1-1 Machikaneyama , Toyonaka , Osaka 560-0043 , Japan.
Radioisotope Research Center , Osaka University , 2-4 Yamadaoka , Suita , Osaka 565-0871 , Japan.
Environ Sci Technol. 2018 Sep 4;52(17):9917-9925. doi: 10.1021/acs.est.8b01697. Epub 2018 Aug 21.
On March 11, 2011, the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident occurred and large amounts of radionuclides were discharged into the atmosphere. We have operated continuous aerosol samplings at four locations in Japan from the accident until the end of 2011. The activities of Sr and Cs in the aerosol samples were measured using low background liquid scintillation counters and high-purity germanium detectors, respectively. The atmospheric Sr and Cs concentrations decreased exponentially during 2011. The time variation of the Sr/Cs ratio was obtained, and we found that the ratio rose from 1.2 × 10 in March to 1.3 × 10 in August 2011. One reason for the increase in the Sr/Cs ratio could be the change in the primary emission source of activity at the FDNPP, which occurred near June 2011.
2011 年 3 月 11 日，福岛第一核电站（FDNPP）事故发生，大量放射性核素排放到大气中。我们在事故发生后至 2011 年底在日本四个地点进行了连续气溶胶采样。使用低本底液体闪烁计数器和高纯锗探测器分别测量气溶胶样品中的 Sr 和 Cs 的活度。2011 年期间，大气中的 Sr 和 Cs 浓度呈指数下降。得到 Sr/Cs 比值的时间变化，我们发现该比值从 3 月的 1.2×10 上升到 2011 年 8 月的 1.3×10。Sr/Cs 比值增加的一个原因可能是 FDNPP 活动的原始排放源发生了变化，这一变化发生在 2011 年 6 月左右。
