1] Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan [2].
Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
Sci Rep. 2014 Mar 31;4:4514. doi: 10.1038/srep04514.
This study used particle size analysis to investigate the initial accumulation and trap efficiency of radiocesium ((137)Cs) in four irrigation ponds, ~4-5 months after the Fukushima Dai-ichi nuclear power plant (DNPP) accident. Trap efficiency, represented by the inventory of (137)Cs in pond sediment to the inventory of radiocesium in soil surrounding the pond (i.e., total (137)Cs inventory), was less than 100% for all but one pond. Trap efficiency decreased as sediment particle size increased, indicating that sediments with a smaller particle size accumulate more (137)Cs. In ponds showing low trap efficiency, fine sediment containing high concentrations of (137)Cs appeared to be removed from the system by hydraulic flushing, leaving behind mostly coarse sediment. The results of this study suggest that sediment particle size can be used to estimate the initial accumulation and trap efficiency of (137)Cs in pond sediment, as well as the amount lost through hydraulic flushing.
本研究使用粒径分析方法，在福岛第一核电站（DNPP）事故发生约 4-5 个月后，调查了四个灌溉池塘中放射性铯（137Cs）的初始积累和捕集效率。除了一个池塘外，所有池塘的捕集效率（以池塘沉积物中 137Cs 的储量与池塘周围土壤中放射性铯总储量的比值表示）均小于 100%。捕集效率随沉积物粒径的增加而降低，表明粒径较小的沉积物积累了更多的 137Cs。在捕集效率较低的池塘中，水力冲刷似乎将含有高浓度 137Cs 的细沉积物从系统中去除，留下的大多是粗沉积物。本研究结果表明，沉积物粒径可用于估算池塘沉积物中 137Cs 的初始积累和捕集效率，以及通过水力冲刷损失的量。
