引用本文:管冬兴,魏天娇,袁召锋,李 刚,陈 正.基于被动采样技术的砷有效性和界面过程研究:进展与展望[J].土壤学报,2021,58(2):344-356. DOI:10.11766/trxb202002290080
GUAN Dongxing,WEI Tianjiao,YUAN Zhaofeng,LI Gang,CHEN Zheng.A Review of Researches on Bioavailability and Interfacial Processes of Arsenic Based on Passive Sampling Techniques: Progress and Prospect[J].Acta Pedologica Sinica,2021,58(2):344-356. DOI:10.11766/trxb202002290080
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基于被动采样技术的砷有效性和界面过程研究:进展与展望
管冬兴,魏天娇,袁召锋,李 刚,陈 正
1.天津大学地球系统科学学院表层地球系统科学研究院, 天津 300072;2.法语鲁汶大学地球与生命研究所, 比利时新鲁汶 B-1348;3.西交利物浦大学健康与环境科学系, 江苏苏州 215123;4.中国科学院城市环境研究所, 厦门 361021
摘要:
全球诸多区域均发现由于人类活动或者地质因素造成的砷污染问题,严重威胁区域生态安全和人体健康。对大尺度下砷风险有效控制,需要准确评价砷在不同介质间的界面行为。砷的迁移转化受到化学和微生物调控,从而在土水和根际等典型环境界面上,具有在毫微米尺度下形态变化剧烈的特点。传统的以破坏性取样加实验室分析为主的主动采样技术难以胜任对界面过程的研究。近年来,以薄膜扩散梯度(DGT)、薄膜扩散平衡(DET)、原位反复孔隙水采样(IPI)和平衡式孔隙水采样(Peeper)为代表的新兴被动采样技术在土壤环境界面过程研究中显示出了巨大优势。上述被动采样技术已用于原位检测水体或土壤间隙水中砷的总量和形态特征及其一维分布信息。其中,DGT测定的土壤中砷浓度与植物体内砷含量的相关性较好,可用于砷的植物有效性评估。利用上述被动采样器研究水-土-生界面处砷的二维时空分布特征,是近几年的一个重要趋势。DGT可用于表征砷在土-水界面和植物根际的二维亚毫米高分辨分布特征,在砷空间分布研究上具有巨大优势。而IPI可低扰动反复采样,是少数可用于砷形态动态分布研究的工具。以上研究从微观尺度阐述砷的生物地球化学行为。最后对今后的研究方向进行了展望。
关键词:  薄膜扩散梯度技术(DGT)  原位反复孔隙水采样器(IPI)  砷形态  生物有效性  土-水界面  植物根际
基金项目:国家自然科学基金项目(41807353,41977320)和西交利物浦大学重点项目建设专项资金(KSF-A-20)资助
A Review of Researches on Bioavailability and Interfacial Processes of Arsenic Based on Passive Sampling Techniques: Progress and Prospect
GUAN Dongxing1, WEI Tianjiao2,3, YUAN Zhaofeng4, LI Gang5, CHEN Zheng4
1.Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China;2.Earth and Life Institute, Environmental sciences, Université3.catholique de Louvain, Louvain-la-Neuve B-1348, Belgium;4.Department of Health and Environmental Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu 215123, China;5.Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
Abstract:
Geological and human activities in quite a number of regions of the world are found to have brought about serious arsenic (As) pollution in soil and groundwater, gravely threatening the ecosystems and human health in those regions. In order to effectively control As pollution risk at large scales, it is necessary to accurately evaluate interfacial behaviors of As in different media. Being regulated by chemical and microbiological factors migration and transformation of the element in certain typical environmental interfaces, like that of soil-water and rhizosphere, exhibit the characteristics of drastic changes in species at μm-to-mm-scales. Conventional active sampling techniques, which mostly consist of destructive field sampling and afterwards sample analysis in lab, have proved to be not good enough to meet the demands of the study on interfacial process of the element, such as handling an element varying drastically in species, quantifying the element at trace levels, and time- and labor-saving. In recent years, passive sampling technology, represented by diffusive gradients in thin-films (DGT), diffusive equilibrium in thin-films (DET), in-situ porewater iterative sampler (IPI) and dialysis sampler (Peeper), has emerged, displaying great advantages over the conventional ones in the research. The DGT device is composed of filter membranes, diffusion gel, binding gel and plastic bases/caps used to fix the three layers of membrane/gel. The filter membrane is mainly used to prevent particles in the environment to be tested from entering the device; the diffusion gel to facilitate free diffusion of ions and formation of a diffusion gradient; and the binding gel, chosen according to the purpose of the experiment, to absorb the pollutants to be tested. DET is a sister technique of DGT, omitting the binding gel phase. The IPI sampler consists of hollow fiber membrane sampling tubes and catheters. For sampling, the sampling tube is filled with deionized water in advance, and ions and small molecules in the environment diffuse into the tube. After the diffusion reaches equilibrium, the solution in the sampling tube is directly pumped out for measurement of concentrations of the ions tested. In principle, Peeper is similar to DET and IPI, but lower in spatial resolution for measurement of porewater concentration. These passive sampling techniques have been used to determine in situ of total As and As speciations in water and soil porewater, and their one-dimensional distribution profiles. DGT-measured As concentration in soil has a good correlation with its content in plants, showing that DGT is suitable for the evaluation of As phytoavailability. It turns out in recent years to be an important trend to use these passive samplers to study two-dimensional spatio-temporal distribution of As at the soil/sediment-water interface. DGT has been used to characterize the two-dimensional distribution of As at soil/sediment-water interface and plant rhizosphere in submillimeter high-resolution, so it cherishes great advantages in the study on spatial distribution of As, whereas IPI can sample iteratively with low disturbance, thus being one of the few tools that can be used to study dynamic distribution of As relative to species. These studies elucidate biogeochemical behaviors of As from a microscale perspective. In the end, the paper describes a prospect of the research in future, including:1) taking advantage of the merits of the passive sampling techniques in future studies on dynamic-controlled processes of As uptake by plants; 2) developing novel passive sampling techniques with both the spatial resolution and the temporal resolution of As concentration taken into account; 3) combining the passive sampling techniques with other 2D sampling techniques, such as planar optodes and soil zymography, in comprehensive studies on biogeochemical process of As in soils and sediments; 4) extending the use of passive sampling techniques to the study on processes of As uptake by fauna living in soils and sediments; and 5) building models of As transporting across interfaces based on data of changes in spatiotemporal concentration of As at the interfaces in complex environmental matrix.
Key words:  Diffusive gradients in thin-films (DGT)  In-situ porewater iterative sampler(IPI)  Arsenic speciation  Bioavailability  Soil/sediment-water interface  Plant rhizosphere