Takeda A, Unno Y, Tsukada H, Takaku Y, Hisamatsu S
Department of Radioecology, Institute for Environmental Sciences, Rokkasho, Japan.
Radiat Prot Dosimetry. 2019 Oct 1;184(3-4):368-371. doi: 10.1093/rpd/ncz103.
The behaviour of I in soil depends on its chemical form in soil solution. Stable I (127I) in the soil solution under actual soil conditions was investigated as a natural analogue of long-lived radioiodine (129I). Soil samples were collected at 5-cm depth intervals down to 20 cm from forests and grasslands in Rokkasho, where the Japanese first commercial nuclear fuel reprocessing plant is located, and the soil solution was extracted by centrifugation. Almost half of total I in the soil solution was iodide, and the other half was dissolved organic I (DOI), with iodate under the detection limit. The proportion of DOI in total I at 0-5 cm depth was larger than the proportions at 5-20 cm depth. The concentration of DOI was positively correlated with that of DOC in the soil solution, suggesting that the behaviour of DOI in the surface soil is affected by labile organic matter dynamics.
碘在土壤中的行为取决于其在土壤溶液中的化学形态。在实际土壤条件下，对土壤溶液中的稳定碘（127I）作为长寿命放射性碘（129I）的天然类似物进行了研究。在日本首个商业核燃料后处理厂所在地六所村的森林和草原中，以5厘米的深度间隔采集土壤样本，直至20厘米深处，然后通过离心法提取土壤溶液。土壤溶液中总碘的近一半是碘化物，另一半是溶解有机碘（DOI），碘酸盐低于检测限。0-5厘米深度处DOI在总碘中的比例大于5-20厘米深度处的比例。DOI的浓度与土壤溶液中溶解有机碳（DOC）的浓度呈正相关，这表明表层土壤中DOI的行为受不稳定有机物动态的影响。
