Uptake and translocation of radiocesium in cedar leaves following the Fukushima nuclear accident
Uptake and translocation of radiocesium in cedar leaves following the Fukushima nuclear accident
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DOI：
10.1016/j.scitotenv.2014.09.063
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发表时间：
2015-01-01
影响因子：
9.8
通讯作者：
Hayashi, Seiji
中科院分区：
文献类型：
--
作者：
Nishikiori, Tatsuhiro;Watanabe, Mirai;Hayashi, Seiji
2011年3月福岛核事故后不久，日本福岛周边地区的柳杉树截获了大气沉积物中存在的Cs-137。研究了~（137）Cs在C.结果表明，在不同的生长期，老叶和新叶中~（137）Cs活性浓度和~（137）Cs/~（133）Cs浓度比（Cs/Cs）均高于老叶。日本收集的森林筑波之间的9和15个月的事故。这两种同位素也分析了穿透雨，散装降水和土壤提取物。大气和土壤来源的水被用来作为代理破译从叶表面和根系的吸收，分别。结果表明，20-40%的Cs-137存在于叶片内部，而60-80%的Cs-137粘附于叶片表面。Cs-137/Cs-133的比率内已发芽的事故发生前的叶片大大高于土壤提取物和低于穿透雨和散装降水。此外，超过80%的Cs-137在穿透雨和散装降水中存在于溶解的形式，这是可用于叶面吸收，这表明一部分的Cs-137内老叶推测是从叶面吸收。事故后发芽的新叶与老叶的Cs-137/Cs-133比值相似，表明内部Cs-137从老叶转移到新叶。除日本山茶以外的17种木本植物中，事故后长出的新叶中也含有Cs-137，其Cs-137/Cs-133比值与土壤提取液相当或高于土壤提取液。这些结果表明，Cs-137的叶片吸收和进一步转运是放射性沉降物期间或之后各种树种污染的重要载体。(C)2014爱思唯尔有限公司版权所有。
Ctyptomeria japonica trees in the area surrounding Fukushima, Japan, intercepted Cs-137 present in atmospheric deposits soon after the Fukushima nuclear accident in March 2011. To study the uptake and translocation of Cs-137 in C. japonica leaves, we analyzed activity concentrations of Cs-137 and the concentration ratios of Cs-137 to Cs-133 (Cs-137/Cs-133) in old and new leaves of C. japonica collected from a forest on Mount Tsukuba between 9 and 15 months after the accident. Both isotopes were also analyzed in throughfall, bulk precipitation and soil extracts. Water of atmospheric and soil origin were used as proxies for deciphering the absorption from leaf surfaces and root systems, respectively. Results indicate that 20-40% of foliar Cs-137 existed inside the leaf, while 60-80% adhered to the leaf surface. The Cs-137/Cs-133 ratios inside leaves that had sprouted before the accident were considerably higher than that of the soil extract and lower than that of throughfall and bulk precipitation. Additionally, more than 80% of Cs-137 in throughfall and bulk precipitation was present in the dissolved form, which is available for foliar uptake, indicating that a portion of the Cs-137 inside old leaves was presumably absorbed from the leaf surface. New leaves that sprouted after the accident had similar Cs-137/Cs-133 ratios to that of the old leaves, suggesting that internal Cs-137 was translocated from old to new leaves. For 17 species of woody plants other than C japonica, new leaves that sprouted after the accident also contained Cs-137, and their Cs-137/Cs-133 ratios were equal to or higher than that of the soil extract. These results suggested that foliar uptake and further translocation of Cs-137 is an important vector of contamination in various tree species during or just after radioactive fallout. (C) 2014 Elsevier B.V. All rights reserved.