环境水样中^(129)I分析及其在环境示踪中的应用  

Analysis of ^(129)I in environmental water samples and its application on environmental tracing

作　　者：姜旭宏[1,2,3] 侯小琳[1,3] 陈宁[1,3] 张路远[1,3] 

机构地区：[1]中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,西安710061 [2]中国科学院大学,北京100049 [3]陕西省加速器质谱技术及应用重点实验室西安加速器质谱中心,西安710061

出　　处：《地球环境学报》2017年第3期203-224,共22页Journal of Earth Environment

基　　金：科技部基础性工作专项项目(2015FY110800);国家自然科学基金项目(41271512;41603125;11605207)~~

摘　　要：^(129)I是碘的唯一长寿命放射性同位素(半衰期为1570万年),目前环境中^(129)I主要来源于人类核活动,尤其是欧洲核燃料后处理厂的排放。人工^(129)I的大量释放使环境中^(129)I的水平大幅度升高,具有明显的空间分布规律,并且随排放时间呈现明显的变化趋势。^(129)I是一种理想的环境示踪剂,可应用于核环境安全监测,包括核事故监测和评价、核燃料后处理厂^(129)I排放和环境影响评价以及应用于环境过程示踪研究。陆地环境水样中稳定碘(127I)水平较低,^(129)I含量更是处于超低水平,因此,准确分析其中超低含量^(129)I及其化学形态是研究难点。本文系统地评述了环境水样中^(129)I及其形态的分析方法,^(129)I的水平、分布及其在核设施环境安全监测和稳定碘的地球化学循环示踪领域应用的研究进展。Background, aim, and scope 129I is the only long-lived radioisotope of iodine （with a half-life of 15.7 million years）. There are two main sources of 129I in the environment, natural and anthropogenic production. 129I is naturally produced through the spallation reaction of atmospheric cosmic rays with Xe in the upper atmosphere, the spontaneous fission of 238U and thermal neutron-induced fission of 235U in the crust, as well as the neutron capture reaction of Te, but this source only accounts for a small part of the 129I inventory in the environment. The main sources of 129I in the present environment are releases from human nuclear activities, including nuclear weapons testing, nuclear reactor operation, nuclear accidents and nuclear fuel reprocessing plants （NFRPs）. Among them, the releases from the NFRPs account for more than 90% of 129I in the environment by now. The releases of anthropogenic 129I have increased the 129I level in the environmental water samples by 3--6 ordersof magnitude compared to the pre-nuclear level, especially in those areas （e.g. Europe, East Asia and North America） close to the point sources such as NFRPs, Fukushima and Chernobyl accident sites. In addition to the significantly spatial variation of 129I level, the records in ice cores, long-term atmospheric depositions and sediment cores have demonstrated variation of 129I level with time： besides a peak value in 1963, increased level was also observed after 1990, which is corresponding to the history of anthropogenic releases of 129I. The iodine concentration in environmental water samples such as atmospheric precipitation, river water, lake water is generally low, and can exist in multi-species. Materials and methods In the environmental water samples, especially in fresh water, organic iodine is an important specie of iodine, which causes a high huge challenge for the accurate determination of ultralow level of 129I in this type of samples. In order to determine the total 129I and speciation analysis of 129I in water

关 键 词：129I 水样 有机碘 形态 环境示踪 

分 类 号：X142[环境科学与工程—环境科学]