Schmidt A, Schnabel C, Handl J, Jakob D, Michel R, Synal H A, Lopez J M, Suter M
Zentrum für Strahlenschutz und Radiökologie (ZSR), Universität Hannover, Germany.
Sci Total Environ. 1998 Nov 10;223(2-3):131-56. doi: 10.1016/s0048-9697(98)00309-x.
Based on a review of literature about the abundances of 129I (T1/2 = 15.7 Ma) in the environment we show that there is a severe lack of knowledge, in particular about natural, pre-nuclear levels. Among the two analytical techniques which are sensitive enough to investigate 129I in environmental materials, namely radiochemical neutron activation analysis (RNAA) and accelerator mass spectrometry (AMS), only AMS is capable of covering the natural, pre-nuclear levels. Since such AMS measurements require chemical separation of iodine from the matrix, a wide variety of separation schemes are necessary for environmental analyses. We report here on such schemes for the analysis of soils, plants and soft tissue. They are applied exemplarily to analyses of soils from the vicinity of Chernobyl. For chemical separations prior to analysis, contamination control and blank analyses are essential. Here, we discuss quality control procedures in detail, both for RNAA and AMS. In the case of AMS we use ion-chromatography (IC) for the determination of stable iodine. The IC analysis is included in the separation schemes for environmental materials. First AMS-analyses of terrestrial biospheric materials demonstrate that natural environmental levels of 129I are lower than previously deduced from investigations using RNAA, but higher than expected from model calculations. AMS is capable of providing the missing knowledge about the radioecology of 129I.
基于对有关环境中碘 - 129（半衰期=1570万年）丰度的文献综述，我们发现存在严重的知识匮乏，尤其是关于天然的、核爆前水平的知识。在对环境材料中碘 - 129进行研究足够灵敏的两种分析技术，即放射化学中子活化分析（RNAA）和加速器质谱分析（AMS）中，只有AMS能够涵盖天然的、核爆前水平。由于此类AMS测量需要从基质中化学分离碘，因此环境分析需要多种分离方案。我们在此报告用于分析土壤、植物和软组织的此类方案。它们被示例性地应用于切尔诺贝利附近土壤的分析。对于分析前的化学分离，污染控制和空白分析至关重要。在此，我们详细讨论了RNAA和AMS的质量控制程序。在AMS的情况下，我们使用离子色谱法（IC）测定稳定碘。IC分析包含在环境材料的分离方案中。对陆地生物圈材料的首次AMS分析表明，碘 - 129的天然环境水平低于先前使用RNAA调查得出的结果，但高于模型计算预期的值。AMS能够提供有关碘 - 129放射生态学缺失的知识。
