ABSTRACT To clarify the factors affecting 137Cs transfer from soil to brown rice in comparison with 133Cs transfer and also to determine the key parameters of the solid-liquid partition coefficient (K d), concentration factor from soil solution to brown rice (CF), and transfer factor from soil to brown rice (TF), we analyzed the results of our previous paper in which a rice pot-culture experiment under different fertilization treatments using three paddy soils in Fukushima 3 years after the Fukushima Daiichi Nuclear Power Station accident was conducted. The TF values for 137Cs were the same as or smaller than the literature values obtained within 2 years of the accident, 2–17 times higher than those for global fallout 137Cs from atmospheric nuclear tests, and 2–20 times higher than those for natural 133Cs. The CF values for 137Cs were negatively correlated with the soil solution K+ concentration. A theoretical approach, under the assumption that 137Cs in soil is mainly adsorbed at the frayed edge site (FES) and ion exchange of 137Cs with K+ and NH4 + ions is in equilibrium, partly explained the variability in the soil solution 137Cs concentrations under different soil and fertilization conditions and suggested that the major portion of 137Cs in soil would be adsorbed in FES under lower K+ and NH4 + concentrations but fixed in the collapsed interlayer sites under higher K+ and NH4 + concentrations, the ranges of which are typically observed in agricultural soils. Our results indicate that the major factors affecting 137Cs transfer from soil to brown rice would be the 137Cs, K+, and NH4 + concentrations in the soil solution and the time elapsed from the deposition of 137Cs, and emphasize the necessity of including the dynamic 137Cs adsorption and fixation process in soil into the TF prediction models applicable to agricultural soils received with periodical fertilizations.

中文翻译：

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影响 137Cs 通过水稻土壤-水稻系统转移的物理化学和时间因素

摘要 与 133Cs 转移相比，阐明影响 137Cs 从土壤转移到糙米的因素，并确定固液分配系数 (K d)、土壤溶液到糙米的浓度因子 (CF) 的关键参数，以及从土壤到糙米 (TF) 的转移因子，我们分析了我们之前的论文的结果，该论文在福岛第一核电站事故 3 年后使用福岛的三种稻田进行了不同施肥处理下的水稻盆栽试验。137Cs 的 TF 值与事故发生后 2 年内获得的文献值相同或小于，比全球大气核试验产生的 137Cs 高 2-17 倍，比天然 133Cs 高 2-20 倍. 137Cs 的 CF 值与土壤溶液 K+ 浓度呈负相关。一种理论方法，假设土壤中 137Cs 主要吸附在磨损边缘位点 (FES) 且 137Cs 与 K+ 和 NH4 + 离子的离子交换处于平衡状态，部分解释了不同土壤下土壤溶液 137Cs 浓度的变异性和施肥条件，表明土壤中的大部分 137Cs 在较低 K+ 和 NH4 + 浓度下会被 FES 吸附，但在较高 K+ 和 NH4 + 浓度下固定在塌陷的夹层位点，其范围通常在农业土壤中观察到. 我们的结果表明，影响 137Cs 从土壤转移到糙米的主要因素是 137Cs、K+、