模拟（137）Cs 在森林地表环境中的动态：在福岛附近受污染森林地点的应用以及对土壤有机质相互作用潜在影响的评估。
Modeling dynamics of (137)Cs in forest surface environments: Application to a contaminated forest site near Fukushima and assessment of potential impacts of soil organic matter interactions.
机构信息
Research Group for Environmental Science, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan.
Research Group for Environmental Science, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan.
出版信息
Sci Total Environ. 2016 May 1;551-552:590-604. doi: 10.1016/j.scitotenv.2016.02.068. Epub 2016 Feb 18.
A process-based model for (137)Cs transfer in forest surface environments was developed to assess the dynamic behavior of Fukushima-derived (137)Cs in a Japanese forest. The model simulation successfully reproduced the observed data from 3year migration of (137)Cs in the organic and mineral soil layers at a contaminated forest near Fukushima. The migration of (137)Cs from the organic layer to the mineral soil was explained by the direct deposition pattern on the forest floor and the turnover of litter materials in the organic layer under certain ecological conditions. Long-term predictions indicated that more than 90% of the deposited (137)Cs would remain within the top 5cm of the soil for up to 30years after the accident, suggesting that the forest acts as an effective long-term reservoir of (137)Cs with limited transfer via the groundwater pathway. The model was also used to explore the potential impacts of soil organic matter (SOM) interactions on the mobility and bioavailability of (137)Cs in the soil-plant system. The simulation results for hypothetical organic soils with modified parameters of (137)Cs turnover revealed that the SOM-induced reduction of (137)Cs adsorption elevates the fraction of dissolved (137)Cs in the soil solution, thereby increasing the soil-to-plant transfer of (137)Cs without substantially altering the fractional distribution of (137)Cs in the soil. Slower fixation of (137)Cs on the flayed edge site of clay minerals and enhanced mobilization of the clay-fixed (137)Cs in organic-rich soils also appeared to elevate the soil-to-plant transfer of (137)Cs by increasing the fraction of the soil-adsorbed (exchangeable) (137)Cs. A substantial proportion (approximate 30%-60%) of (137)Cs in these organic-rich soils was transferred to layers deeper than 5cm decades later. These results suggested that SOM influences the behavior of (137)Cs in forests over a prolonged period through alterations of adsorption and fixation in the soil.
建立了一个基于过程的模型，用于描述（137）Cs 在森林地表环境中的迁移，以评估福岛核事故后（137）Cs 在日本森林中的动态行为。该模型模拟成功再现了福岛附近受污染森林中（137）Cs 在有机和矿物质土壤层中 3 年迁移的观测数据。（137）Cs 从有机层向矿物质土壤的迁移可以用森林地表上的直接沉积模式和有机层中凋落物材料的转化来解释，这是在一定生态条件下发生的。长期预测表明，事故发生后长达 30 年内，超过 90%的沉积（137）Cs 将保留在土壤表层 5cm 内，这表明森林是（137）Cs 的有效长期储存库，通过地下水途径的迁移有限。该模型还用于探索土壤有机质（SOM）相互作用对土壤-植物系统中（137）Cs 迁移性和生物可利用性的潜在影响。通过改变（137）Cs 周转率的参数对假设的有机土壤进行模拟，结果表明，SOM 引起的（137）Cs 吸附减少提高了土壤溶液中溶解（137）Cs 的比例，从而增加了（137）Cs 从土壤到植物的转移，而不会显著改变（137）Cs 在土壤中的分馏。粘土矿物剥离边缘位点上（137）Cs 的固定速度较慢，富含有机质的土壤中粘土固定的（137）Cs 的迁移能力增强，这也似乎增加了土壤吸附（可交换）（137）Cs 的比例，从而增加了（137）Cs 从土壤到植物的转移。几十年后，这些富含有机质的土壤中约有 30%-60%的（137）Cs 转移到了 5cm 以下的土层。这些结果表明，SOM 通过改变土壤中的吸附和固定作用，在较长时间内影响森林中（137）Cs 的行为。
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