Concentration and specific activity of fallout 137Cs in extracted and particle-size fractions of cultivated soils
Concentration and specific activity of fallout 137Cs in extracted and particle-size fractions of cultivated soils
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DOI：
10.1016/j.jenvrad.2007.11.014
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发表时间：
2008-06-01
影响因子：
2.3
通讯作者：
Inaba, Jiro
中科院分区：
文献类型：
--
作者：
Tsukada, Hirofumi;Takeda, Akira;Inaba, Jiro
用两种萃取剂（1 M的CH_3COONH_4溶液和0.8M的CH_3COONH_4/5%HNO_3溶液）分离土壤中沉降的~（137）Cs和稳定态Cs。去除可氧化有机结合部分后剩余的残余物用筛分和沉淀方法分离成包括粘土、粉土、细砂和粗砂的粒度部分。然后，Cs-137和稳定Cs的浓度在提取馏分和粒度级分进行了测定。土壤中可交换态和有机结合态的~（137）Cs含量分别约为10%和20%。Cs-137在强结合组分中的含量约为70%，且在粘土中的含量最高。（CS）-C-137的比活度（沉降Cs-137/稳定Cs的浓度比）按可交换组分、有机结合组分和强结合组分的顺序降低。这些数据表明，Cs-137和稳定Cs之间的平衡并没有在这些部分中达到，尽管沉积在土壤中的大多数Cs-137来自几十年前发生的放射性尘埃武器试验。各土壤中不同粒级的~（137）Cs浓度不同，而各粒级~（137）Cs比活度值相对相似。(C)2007爱思唯尔有限公司保留所有权利。
Fallout Cs-137 and stable Cs in soils were separated with two extractants (1 M CH3COONH4 solution and 0.8 M CH3COONH4 in 5% HNO3 solution after H2O2 oxidization). The residue remaining after removal of the oxidizable organic-bound fraction was separated into the particle-size fractions including clay, silt, fine sand and coarse sand with a sieving and sedimentation method. Then, the concentrations of Cs-137 and stable Cs in the extracted fractions and the particle-size fractions were determined. The Cs-137 contents in the exchangeable and organic-bound fractions in the soil were approximately 10 and 20%, respectively. The Cs-137 content in the strongly bound fraction was about 70%, and the concentration of Cs-137 in the clay was the richest among the particle-size fractions. The specific activity of (CS)-C-137 (concentration ratio of fallout Cs-137/stable Cs) decreased in the order exchangeable, organic-bound and strongly bound fractions. The data suggest that equilibrium between Cs-137 and stable Cs was not reached among those fractions, even though most of the Cs-137 that had been deposited on the soil was derived from fallout weapons tests that occurred several decades ago. The concentration of Cs-137 among the particle-size fractions in each soil was different, whereas the specific activity of Cs-137 in the particle-size fractions had a relatively similar value. (C) 2007 Elsevier Ltd. All rights reserved.