Kurihara Momo, Onda Yuichi, Kato Hiroaki, Loffredo Nicolas, Yasutaka Tetsuo, Coppin Frederic
National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan.
Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 305-8577, Japan.
J Environ Radioact. 2018 Jul;187:81-89. doi: 10.1016/j.jenvrad.2018.01.027. Epub 2018 Feb 7.
Cesium-137 (Cs) migration in the litter layer consists of various processes, such as input via throughfall, output via litter decomposition, and input from deeper layers via soil organism activity. We conducted litter bag experiments over 2 years (December 2014-November 2016) to quantify the inputs and outputs of Cs in the litter layer in a Japanese cedar plantation (Cryptomeria japonica) and a mixed broadleaf forest dominated by Quercus serrata located 40 km northwest of the Fukushima Dai-ichi Nuclear Power Plant. The experiments included four conditions, combining contaminated and non-contaminated litter and deeper layer material, and the inputs and outputs were estimated from the combination of Cs increases and decreases in the litter layer under each condition. The Cs dynamics differed between the two forests. In the C. japonica forest, some Cs input via throughfall remained in the litter layer, and downward Cs flux passed through the litter layer was 0.42 (/year).Upward flux of Cs from the deeper layer was very restricted, < 0.017 (/year). In the broadleaf forest, migration of Cs in throughfall into deeper layers was restricted, downward Cs flux was less than 0.003 (/year).Upward input of Cs from the deeper layer was prominent, 0.037 (/year). Cs output via litter decomposition was observed in both forests. The flux in the C. japonica forest was slower than that in the broadleaf forest, 0.12 and 0.15 (/year), respectively.
铯 - 137（Cs）在凋落物层中的迁移由多种过程组成，例如通过穿透雨输入、通过凋落物分解输出以及通过土壤生物活动从更深层输入。我们在两年时间（2014年12月至2016年11月）内进行了凋落物袋实验，以量化日本福岛第一核电站西北40公里处的日本柳杉人工林（Cryptomeria japonica）和以锯齿栎为主的阔叶混交林中凋落物层中Cs的输入和输出。实验包括四种条件，将受污染和未受污染的凋落物及深层物质进行组合，并根据每种条件下凋落物层中Cs的增加和减少情况来估算输入和输出。两种森林中Cs的动态变化有所不同。在日本柳杉林中，通过穿透雨输入的一些Cs留在了凋落物层，穿过凋落物层的向下Cs通量为0.42（/年）。从更深层向上的Cs通量非常有限，<0.017（/年）。在阔叶林中，穿透雨中的Cs向更深层的迁移受到限制，向下的Cs通量小于0.003（/年）。从更深层向上的Cs输入较为显著，为0.037（/年）。在两种森林中均观察到了通过凋落物分解的Cs输出。日本柳杉林中的通量比阔叶林中的慢，分别为0.12和0.15（/年）。
