Spatiotemporal Variation of Radiocesium in Coastal and Oceanic Seawater
Spatiotemporal Variation of Radiocesium in Coastal and Oceanic Seawater
复制标题
沿海和大洋海水中放射性铯的时空变化
DOI：
10.1007/978-981-16-6799-2_12
复制
发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Kumamoto Yuichiro
中科院分区：
文献类型：
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作者：
Takata Hyoe;Kumamoto Yuichiro
本文综述了2011年日本福岛第一核电站（FNPP 1）核泄漏事故中溶解态放射性铯的海洋放射性监测、来源及其时空变化。在第一年，即2011财政年度（2011财政年度），沿海和近海地区的监测站根据放射性铯的扩散情况有所增加，自2012财政年度以来一直固定。一个问题是，不同监测目的的不同设施报告的放射性铯数据的探测极限从1 Bq m− 3到1000 Bq m− 3不等。FNPP 1产生的放射性铯的两个主要来源，大气沉降和直接排放的可能范围估计分别为9-12 PBq（petabequerel）和3-5 PBq。尽管FNPP 1的持续直接释放有所下降，但沿海地区的放射性浓度仍高于事故前的浓度。这主要是由于沉积在陆地上的FNPP 1衍生放射性铯的河流输送。沉积和排放到FNPP 1沿岸和近海的放射性铯沿表层流向东沿着迁移。它在2016年到达北美大陆，然后沿着亚北极环流向西返回。黑潮锋南侧沉积的放射性铯随北太平洋副热带模态水（STMW）的形成/俯冲而沿着向南输送。这导致了FNPP 1产生的放射性铯在2013年被输送到亚热带地区的西端，东海东部，然后是日本海。
We review the marine radioactive monitoring, sources, and spatiotemporal change of dissolved radiocesium released from the Fukushima Dai-ichi Nuclear Power Plant (FNPP1) accident in 2011 during the past decade. The monitoring stations in the coastal and offshore areas increased according to the spread of radiocesium in the first year, Fiscal Year 2011 (FY2011), and have been fixed since FY2012. A problem arose from different detection limits from 1 to 1000 Bq m−3with radiocesium data reported by different facilities that have different monitoring purposes. The probable range of the two major sources of the FNPP1-derived radiocesium, the atmospheric deposition and direct discharge, is estimated to be 9–12 PBq (petabequerel) and 3–5 PBq, respectively. Despite the decline of ongoing direct release from the FNPP1, the activity concentrations in the coastal area are still higher than the concentrations before the accident. This is mainly due to riverine transport of the FNPP1-derived radiocesium deposited on the land. The radiocesium deposited on and discharged into the coastal and offshore areas of the FNPP1 was transported eastward along the surface currents. It had reached the North American Continent by 2016 and then returned westward along with the subarctic gyre current. The radiocesium deposited just south of the Kuroshio Front was conveyed southward in subsurface layers along with the formation/subduction of the Subtropical Mode Water (STMW) in the North Pacific Ocean. This resulted in the transport of the FNPP1-derived radiocesium to the western end of the subtropical area, the eastern East China Sea, and then the Japan Sea by 2013.