同步辐射X射线荧光和吸收谱技术在环境汞污染研究中的应用进展

汞作为一种重要的全球性重金属污染物,被许多国际组织列为优先控制污染物。常规的汞分析手段,例如电感耦合等离子体质谱(ICP-MS)、原子荧光光谱(AFS)等,对汞的分析精度较高,方法比较成熟,但对样品前处理要求也较高。同步辐射技术由于其高、精、准的优势,且对样品前处理要求比较简单、可实现原位无损分析,因此被广泛应用于环境样品的分析中。随着研究的发展,同步辐射X射线荧光光谱(SRXRF)和同步辐射X射线吸收光谱(SRXAS)技术在环境汞污染分析领域得到了越来越多的应用。主要介绍了我国环境汞污染现状及污染特征,同步辐射技术对于汞分布蓄积、含量和化学形态分析方面的独特优势,重点回顾了本项目组和其他一些研究组近几年关于SRXRF和SRXAS技术在环境介质如土壤、植物体内汞的分布蓄积、相对含量和化学形态转化研究领域的应用进展,对进一步发展并提高同步辐射技术在环境及生物体汞污染水平、毒性机理和生态毒理评价方面的应用进行了展望。

Review of Studies Using Synchrotron Radiation X-Ray Fluorescence and X-Ray Absorption Spectrum Techniques on Environmental Hg Pollution

Mercury (Hg) is considered as a prior-controlled heavy metal pollutant by many international committees. The conventional Hg analysis methods include High Performance Liquid Chromatography combined with Inductive Coupled Plasma Mass Spectrometry (HPLC-ICP-MS), Atomic Fluorescence Spectroscopy (AFS) and so on, which have an advantage of high analytical precision and a disadvantage of high demand for sample pretreatment. Synchrotron Radiation (SR) technique has the characteristics of high energy, high precision and high accuracy, which give it an unique advantage for Hg analysis. With Hg researches advance, SR X-ray fluorescence spectrometry (XRF) and X-ray absorption spectrum (XAS) are increasingly used in the Hg analysis. In this work, the current Hg pollution status in China, as well as the advantages of SR-XRF and SR-XAS techniques used in Hg analysis have been briefly summarized. We reviewed the recent SR-XRF and SR-XAS studies carried out in our research team and others about the Hg behaviors in the environmental medium, like soil and plants. The authors also prospected the foreground of application of SR techniques in further studying the mechanism of Hg bio-toxicity and assessing the ecotoxicology of Hg in environment.