Sasaki Yoshito, Abe Hironobu, Mitachi Katsuaki, Watanabe Takayoshi, Ishii Yasuo, Niizato Tadafumi
Fukushima Environmental Safety Center, Japan Atomic Energy Agency, Sahei 8F, 1-29, Okitama-cho, Fukushima-shi, Fukushima 960-8034 Japan.
Fukushima Environmental Safety Center, Japan Atomic Energy Agency, Sahei 8F, 1-29, Okitama-cho, Fukushima-shi, Fukushima 960-8034 Japan.
J Environ Radioact. 2016 Sep;161:58-65. doi: 10.1016/j.jenvrad.2015.12.001. Epub 2015 Dec 21.
We report on the behavior of radiocesium in tree bark and its transfer into the stemflows of chestnut trees in a forest in the Fukushima Prefecture, Japan. In stems that were present at the time of the accident, the radiocesium concentration of the bark was found to be approximately 10 times that of the wood. The average (137)Cs concentration of the dissolved fraction (<0.45 μm) in the stemflow was measured to be around 10 Bq/L. The (137)Cs concentration ratio [present at the time of the accident (Bq/kg) in the bark/the dissolved fraction in the stemflow (Bq/L)] was approximately 10(3). A strong positive correlation was observed between the radiocesium concentration and the electrical conductivity of the dissolved fraction of the stemflow; this result suggests that radiocesium and electrolytes have the same elution mechanism from the tree. The size fractionation analysis of the <0.45 μm fraction through ultrafiltration revealed that the radiocesium was present as an almost dissolved species. Some of the particles in the particulate fraction (>0.45 μm) of the stemflow were strongly adsorbed radiocesium.
我们报告了日本福岛县某森林中放射性铯在树皮中的行为及其向栗树树干径流的转移情况。在事故发生时就已存在的树干中，发现树皮的放射性铯浓度约为木材的10倍。测得树干径流中溶解部分（<0.45μm）的平均（137）铯浓度约为10 Bq/L。（137）铯浓度比[事故发生时树皮中的（Bq/kg）/树干径流中溶解部分的（Bq/L）]约为10³。观察到放射性铯浓度与树干径流溶解部分的电导率之间存在强正相关；该结果表明放射性铯和电解质从树木中的洗脱机制相同。通过超滤对<0.45μm部分进行的粒度分级分析表明，放射性铯几乎以溶解态存在。树干径流颗粒部分（>0.45μm）中的一些颗粒强烈吸附了放射性铯。
