Vertical distributions of plutonium isotopes in marine sediment cores off the Fukushima coast after the Fukushima Dai-ichi Nuclear Power Plant accident
Vertical distributions of plutonium isotopes in marine sediment cores off the Fukushima coast after the Fukushima Dai-ichi Nuclear Power Plant accident
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DOI：
10.5194/bg-10-2497-2013
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发表时间：
2013-04
期刊：
影响因子：
4.9
通讯作者：
W. Bu;W. Bu;Jian Zheng;T. Aono;K. Tagami;S. Uchida;Jing Zhang;M. Honda;Q. Guo;M. Yamada
中科院分区：
文献类型：
--
作者：
W. Bu;W. Bu;Jian Zheng;T. Aono;K. Tagami;S. Uchida;Jing Zhang;M. Honda;Q. Guo;M. Yamada
福岛第一核电站（FDNPP）事故导致大量放射性核素释放到大气中以及直接排放到海洋中。相对于对高挥发性裂变产物如131i、134cs和137cs的分布的深入研究，对锕系元素，尤其是Pu同位素的类似研究还很有限。为了获得海洋沉积物中Pu同位素的垂直分布，更好地评估FDNPP事故对海洋环境可能造成的Pu污染，我们于2011年7月至2012年7月在福岛西北太平洋海域采集的沉积物岩心样品中测定了239+240和241 Pu的活度以及240 / 239和241 / 239 Pu的原子比。我们还测量了在FNDPP事故发生前从7个日本河口采集的表层沉积物样本，以建立全面的背景基线数据。北太平洋西部沉积物的铀活度和铀原子比的观测结果与基线数据相当，表明FDNPP事故在采样时间之前并未对研究区域造成可检测到的铀污染。北太平洋西部离福岛海岸30公里处的钚同位素来自全球沉降物和太平洋试验场近距离沉降物。
The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident led to the release of large amounts of radionuclides into the atmosphere as well as direct discharges into the sea. In contrast to the intensive studies on the distribution of the released high volatility fission products, such as 131 I, 134 Cs and 137 Cs, similar studies of the actinides, especially the Pu isotopes, are limited. To obtain the vertical distribution of Pu isotopes in marine sediments and to better assess the possible contamination of Pu from the FDNPP accident in the marine environment, we determined the activities of 239+240 Pu and 241 Pu as well as the atom ratios of 240 Pu/ 239 Pu and 241 Pu/ 239 Pu in sediment core samples collected in the western North Pacific off Fukushima from July 2011 to July 2012. We also measured surface sediment samples collected from seven Japanese estuaries before the FNDPP accident to establish the comprehensive background baseline data. The observed results of both the Pu activities and the Pu atom ratios for the sediments in the western North Pacific were comparable to the baseline data, suggesting that the FDNPP accident did not cause detectable Pu contamination to the studied regions prior to the sampling time. The Pu isotopes in the western North Pacific 30 km off the Fukushima coast originated from global fallout and Pacific Proving Ground close-in fallout.