Remobilization of radiocesium on riverine particles in seawater: The contribution of desorption to the export flux to the marine environment
Remobilization of radiocesium on riverine particles in seawater: The contribution of desorption to the export flux to the marine environment
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海水中河流颗粒上放射性铯的再活化：解吸对海洋环境输出通量的贡献
DOI：
10.1016/j.marchem.2015.07.004
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发表时间：
2015
期刊：
影响因子：
3
通讯作者：
M. Kusakabe
中科院分区：
文献类型：
--
作者：
H. Takata;Kazuyuki Hasegawa;S. Oikawa;N. Kudo;T. Ikenoue;R. Isono;M. Kusakabe
我们评估了从河流颗粒中解吸的放射性铯（137Cs）对从河流到海洋环境的溶解性137Cs出口通量的影响，在海洋环境中，它可能会积聚并集中在海洋生物群中。样本采集自Abukuma河（2013年12月）、Kuji河（2013年11月）、Naka河（2013年11月）和Tone河（2013年10月）沿岸的站点，这些站点聚集了大量福岛第一核电站（FNPP）事故的放射性核素。我们通过将河岸土壤和河底沉积物中筛过的颗粒（< 74 μm）加入过滤后的（< 0.45 μm）海水中，进行颗粒-海水分配和解吸实验，估计了河流颗粒的解吸程度。添加颗粒后，由于颗粒中的137cs被解吸，溶解态137cs浓度迅速增加，然后趋于恒定。7d后的解吸137cs分数（即海水中解吸137cs相对于颗粒中初始总量的比例）在0.75 ~ 6.6%之间。解吸137cs组分的变化反映了颗粒（粘土矿物、Fe/Mn氧化物/水合氧化物和有机物）组成的变化，控制了吸附-解吸反应。我们用两种方法计算了每条河流向沿海地区的出口通量：(1)用河流中解吸部分和溶解浓度的总和乘以河流流量（即含解吸部分的流量），(2)仅用河流中溶解浓度乘以流量（不含解吸部分的流量）。在正常流量条件下，Abukuma河的137cs通量为72 ~ 86 MBq/d， Kuji河的137cs通量为4.4 ~ 4.6 MBq/d。这些通量分别比不含解吸馏分计算的通量大2.5 ~ 21.9%和1.1 ~ 9.9% （Abukuma, 71 MBq/d; Kuji, 4.2 MBq/d）。在大流量条件下，河流可能会向海洋环境携带更大的高137cs悬浮颗粒负荷（约1000 Bq/kg-dry），从而增加解吸对溶解137cs输出通量的贡献。这些结果表明，在估计从河流到FNPP附近沿海地区的放射性铯通量时，必须考虑活性颗粒Cs（即可脱吸部分）。
We evaluated the influence of radiocesium (137Cs) desorbed from riverine particles on the export flux of dissolved137Cs from rivers to the marine environment, where it may accumulate and become concentrated in marine biota. The samples were collected from stations along the Abukuma (December 2013), Kuji (November 2013), Naka (November 2013), and Tone (October 2013) rivers, in the catchments of which large quantities of radionuclides from the Fukushima Dai-ichi Nuclear Power Plant (FNPP) accident were deposited. We estimated the extent of the desorbed fraction from riverine particles by conducting a particle–seawater partitioning and desorption experiment in which sieved particles (< 74 μm) from the riverbank soils and river-bottom sediments were added to filtered (< 0.45 μm) seawater. After the addition of the particles, the dissolved137Cs concentration increased rapidly as a result of desorption of137Cs from the particles, and then became approximately constant. The desorbed137Cs fraction (i.e., the amount desorbed in seawater relative to the initial total amount in the particles) after 7 d ranged from 0.75 to 6.6%. This variability in the desorbed137Cs fraction reflects the varied composition of the particles (clay minerals, Fe/Mn oxides/hydrous oxides, and organic matter), which controls the adsorption–desorption reaction. We calculated the export flux from each river to the coastal area in two ways: (1) by multiplying the sum of the desorbed fraction and dissolved concentration in the river water by the river discharge (i.e., the flux with the desorbable fraction), and (2) by multiplying just the dissolved concentration in the river water by the discharge (the flux without the desorbable fraction). The estimated137Cs flux under normal flow conditions when the desorbed fraction was included was 72–86 MBq/d from the Abukuma River, and 4.4–4.6 MBq/d from the Kuji River. These fluxes are respectively 2.5–21.9% and 1.1–9.9% larger than the fluxes calculated without the desorbed fraction (Abukuma, 71 MBq/d; Kuji, 4.2 MBq/d). Under high-flow conditions, the rivers would likely carry a greater suspended particle load with high137Cs (> 1000 Bq/kg-dry) to the marine environment, thereby increasing the contribution of desorption to the export flux of dissolved137Cs. These results show that reactive particulate Cs (i.e., the desorbable fraction) must be taken into account when estimating the radiocesium fluxes from rivers to coastal regions near the FNPP.
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DOI：
--
发表时间：
2021
期刊：
影响因子：
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作者：
鎌戸 隆行;東 真太郎;岡崎 啓史;藤崎 俊平;黒澤 耕介;玄田 英典;氏原秀樹,市川隆一,関戸衛,宗包浩志,宮原伐折羅,小林知勝,寺家孝明,小山友明,竹内央,今井裕
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DOI：
10.1073/pnas.1112058108
发表时间：
2011-12-06
影响因子：
11.1
作者：
Yasunari, Teppei J.;Stohl, Andreas;Yasunari, Tetsuzo
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DOI：
--
发表时间：
2012
期刊：
影响因子：
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作者：
林田翔平;左右田稔; 伊藤晋一;横尾哲也;大串研也;川名大地;H. M. Ronnow;益田隆嗣;S.Takeuchi;Enescu Bogdan
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