210Pb, 137Cs and 239,240Pu in East China Sea sediments: sources, pathways and budgets of sediments and radionuclides
210Pb, 137Cs and 239,240Pu in East China Sea sediments: sources, pathways and budgets of sediments and radionuclides
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DOI：
10.1016/s0025-3227(02)00165-2
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发表时间：
2002-04
期刊：
影响因子：
2.9
通讯作者：
C. Su;C. Huh
中科院分区：
文献类型：
--
作者：
C. Su;C. Huh
通过对东海不同沉积体系83个沉积物柱样中~（210）Pb、~（137）Cs和~（239）240 Pu的剖面分析，探讨了沉积物中~（210）Pb、~（137）Cs和~（239）240 Pu的来源、途径和收支。沉积速率和核素含量的分布表明，沉积物、137 Cs和239，240 Pu从长江口向南沿岸迁移，主要集中在水深<70 m的内陆架区域。质量平衡计算表明，东海是颗粒反应性210 Pb和239，240 Pu的汇，约六分之一的沉积物预算通过边界清除提供。相反，由于137 Cs对颗粒物的亲和力较低和陆架水的快速周转，东海是137 Cs的来源。累积输入的137 Cs中约有三分之二已被运出东海，其余三分之一储存在底层沉积物和上覆水体中。至于沉积物预算，无法建立质量平衡，因为根据迄今为止记录的输入项与本研究得出的沉积通量之间的比较，沉积物供应短缺超过30%。这很可能是我们高估了沉积物的埋藏通量，或者低估了从黄河扩散系统到东海的长距离输运。或者，这种不平衡可以用十年至百年时间尺度上的沉积物输入和输出之间的差异来解释。
Profiles of210Pb,137Cs and239,240Pu measured in 83 sediment cores collected from various sedimentary regimes in the East China Sea were analyzed to elucidate the sources, routes and budgets of sediments as well as these radionuclides. Distributions of sedimentation rates and nuclide inventories reveal alongshore transport of sediments,137Cs and239,240Pu from the mouth of the Yangtze River toward the south, largely confined to the inner-shelf area (water depth <70 m). Mass balance calculations suggest that the East China Sea is a sink for the particle-reactive210Pb and239,240Pu, with about one-sixth of their sedimentary budgets supplied via boundary scavenging. In contrast, due to lower affinity of137Cs for particles and rapid turnover of the shelf water, the East China Sea serves as a source for137Cs. About two-thirds of the cumulative input of137Cs have been transported out of the East China Sea, leaving the remaining one-third stored in the bottom sediments and the overlying water column. As for the sediment budget, mass balance cannot be established due to a shortfall in sediment supply of more than 30% based on a comparison between input terms documented thus far and the sedimentation flux derived from this study. It is very likely that we have overestimated the sediment burial flux or that long-distance transport from the Yellow River’s dispersal system to the East China Sea is underestimated. Alternatively, the imbalance could be explained by the discrepancy between sediment input and output on decadal to centennial timescales.