The isotopic signature of fallout plutonium in the North Pacific
The isotopic signature of fallout plutonium in the North Pacific
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DOI：
10.1016/s0265-931x(96)00071-9
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发表时间：
1997-01-01
影响因子：
2.3
通讯作者：
Buesseler, KO
中科院分区：
文献类型：
--
作者：
Buesseler, KO
对北太平洋中部法国护卫舰浅滩的一份过时珊瑚记录进行的钚分析表明，该盆地的钚有两个主要来源：20世纪50年代在马歇尔群岛太平洋试验场进行核武器试验产生的近距离（对流层）沉降物和1962年达到峰值的全球（平流层）沉降物。此外，太平洋试验场沉降物的Pu-240/Pu-239原子比（0.24）明显高于全球沉降物Pu的原子比（0.18-0.19）。来自北太平洋的海水和沉积物样品显示出范围很广的Pu-240/Pu-239值（0.19-0.34），在次表层沃茨和沉积物中的比值有升高的趋势。相对于远离这一近距离沉降物源的站点，马歇尔群岛附近的深水钚-240/钚-239比率较高。这些初步数据表明，太平洋试验场的放射性尘埃钚比全球放射性尘埃钚更快地从表面沃茨中清除。钚地球化学似乎与不同沉降物源产生的含钚颗粒的物理/化学形式有关。(C)1997年爱思唯尔科学有限公司。
Plutonium analyses of a dated coral record from the French Frigate Shoals in the central North Pacific indicate that there are two major sources of Pu in this basin: close-in (tropospheric) fallout from nuclear weapons testing at the Pacific Proving Grounds in the Marshall Islands in the 1950s and global (stratospheric) fallout which peaked in 1962. Furthermore, the Pu-240/Pu-239 atom ratio of fallout from the Pacific Proving Grounds is characteristically higher (0.24) than that of global fallout Pu (0.18-0.19). Seawater and sediment samples from the North Pacific exhibit a wide range of Pu-240/Pu-239 values (0.19-0.34), with a trend towards higher ratios in the subsurface waters and sediment. Deep water Pu-240/Pu-239 ration are higher in the vicinity of the Marshall Islands relative to stations further from this close-in fallout source. These preliminary data suggest that fallout Pu from the Pacific Proving Grounds is more rapidly removed from the surface waters than is global fallout Pu. Plutonium geochemistry appears to be related to the physical/chemical form of Pu-bearing particles generated by different fallout sources. (C) 1997 Elsevier Science Limited.