Department of Radioecology, Institute for Environmental Sciences, Rokkasho, Japan.
Institute of Environmental Radioactivity, Fukushima University, Fukushima, Japan.
Radiat Prot Dosimetry. 2022 Sep 9;198(13-15):1047-1051. doi: 10.1093/rpd/ncac051.
The soil-soil solution distribution coefficient (Kd) of radioiodine in soil samples with various total carbon (TC) contents was measured in a batch sorption experiment using 125I tracer spiked as I-. The log values of Kd-125I and TC concentration in low-TC soils (< 10g kg-1) were positively correlated, whereas those of Kd-125I in TC rich soils (> 10 g kg-1) and dissolved organic carbon (DOC) in liquid phase were negatively correlated. The proportion of 125I in the < 3 kDa fraction in the liquid phase is negatively correlated with the log of DOC, implying that 125I is primarily combined with high-molecular-weight organic matter in soil solutions rich in DOC. The results suggest that Kd-125I in soil with high soil organic material (SOM) content is governed by DOC via the combination of 125I and DOC. In contrast, Kd-125I in soils with a low SOM content was governed by SOM because the anion exchange capacity of SOM was vital for the sorption of 125I-.
使用 125I 示踪剂作为 I-，通过批量吸附实验测量了具有不同总碳 (TC) 含量的土壤样品中放射性碘的土壤-溶液分配系数 (Kd)。低 TC 土壤 (<10g kg-1) 中 Kd-125I 和 TC 浓度的对数呈正相关，而 TC 丰富土壤 (>10 g kg-1) 和液相中溶解有机碳 (DOC) 的 Kd-125I 呈负相关。液相中<3 kDa 级分中 125I 的比例与 DOC 的对数呈负相关，这表明 125I 主要与富含 DOC 的土壤溶液中的高分子量有机物结合。结果表明，高土壤有机质 (SOM) 含量土壤中的 Kd-125I 受 DOC 控制，通过 125I 和 DOC 的结合。相比之下，SOM 含量低的土壤中的 Kd-125I 受 SOM 控制，因为 SOM 的阴离子交换能力对 125I-的吸附至关重要。
