梯度扩散薄膜技术(DGT)的理论及其在环境中的应用Ⅱ：土壤与沉积物原位高分辨分析中的方法与应用

Theory and application of diffusive gradients in thin-films in the environment:High-resolution analysis and its applications in soils and sediments

从吸附膜的设计、采样装置的设计和分析方法三个方面系统介绍了梯度扩散薄膜技术(DGT)在土壤和沉积物介质中原位高分辨研究的方法学,并回顾了DGT自诞生以来在根际土壤和沉积物中原位高分辨应用所取得的重要研究成果,最后探讨了DGT在原位高分辨研究中的发展前景。DGT技术在沉积物和土壤中对污染物微界面机制的原位高分辨率研究,能够揭示控制重金属污染的关键过程,为针对性地做出管理控制方案提供了重要理论支持,从而推动我国对土壤、沉积物污染的防治和粮食安全的控制。

In this paper, we systematically introduce the methodology of in situ high-resolution application of diffusive gradients in thin-films（DGT）in soil and sediment media in terms of design of binding gels, design of sampling devices, and methods of analysis. Important research results obtained from the in situ high-resolution application in the rhizosphere and sediment since the advent of DGT were also reviewed. The discovery of the highly localized distribution and correlated release of sulfide and metals in sediment and the localized flux maxima of metals around plant roots in soil were both enabled by the in situ high-resolution DGT application. With the combined application of complementary planar optode techniques, 2-D distribution of key environmental parameters such as O2 and pH could also be imaged with ideal spatiotemporal relevance with DGT-measured species. In the end, the outlook on future DGT in situ high-resolution research was made to the development of a novel highly homogeneous binding gel for a wider spectrum of environmentally important analytes and further application in soils and sediments targeting decisive biogeochemical processes. With the recent establishment of the Action Plan for Soil Pollution Prevention and Control and the background that China is paying more attention to enhancing its environment, the in situ high-resolution study on the micro-interfacial mechanisms of pollutants in soil and sediment by DGT is capable of revealing key controlling processes in heavy metal contamination and providing important theoretical supports for management strategies accordingly, thus promoting the prevention and remediation of soil and sediment pollution as well as the control of crop safety in China.