Bostock A C, Shaw G, Bell J N B
Department of Environmental Science and Technology, Imperial College, Silwood Park, Ascot, Berkshire SL5 7PY, UK.
J Environ Radioact. 2003;70(1-2):29-42. doi: 10.1016/S0265-931X(03)00120-6.
129I is a potentially important radionuclide in safety assessments of proposed deep geological radioactive waste repositories due to its radiotoxicity, high mobility and long physical half-life (15.7 million years). In soils, iodine is present both in an inorganic form and in organohalide complexes, some of which are volatile under natural environmental conditions. This study has examined volatilisation, sorption and the effect of freezing on sorption and loss of (125)I (physical half-life 60.2 days), as a surrogate for (129)I, within coniferous forest and grassland soils. The results do not suggest that volatilisation from these soils is a significant pathway for the transport of (129)I. Strong and specific sorption of iodine to humic substances has been demonstrated, which is reduced at freezing temperatures. It is hypothesised that rapid sorption to soil humic substances can significantly reduce volatilisation rates. The effect of freezing conditions on iodine extractability from soils suggests a microbially mediated sorption process.
由于其放射性毒性、高迁移率和长物理半衰期（1570万年），碘-129在拟议的深部地质放射性废物处置库安全评估中是一种潜在的重要放射性核素。在土壤中，碘以无机形式和有机卤化物络合物形式存在，其中一些在自然环境条件下是挥发性的。本研究考察了作为碘-129替代物的碘-125（物理半衰期60.2天）在针叶林土壤和草地土壤中的挥发、吸附以及冷冻对吸附和损失的影响。结果表明，这些土壤中的挥发不是碘-129迁移的重要途径。已证明碘与腐殖质有强烈且特异性的吸附作用，在冷冻温度下这种吸附作用会减弱。据推测，对土壤腐殖质的快速吸附可显著降低挥发速率。冷冻条件对土壤中碘提取率的影响表明存在微生物介导的吸附过程。
