Use of diffusive gradients in thin-films for studies of chemical speciation and bioavailability
Use of diffusive gradients in thin-films for studies of chemical speciation and bioavailability
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DOI：
10.1071/en14105
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发表时间：
2015-01-01
影响因子：
4.3
通讯作者：
Davison, William
中科院分区：
文献类型：
--
作者：
Zhang, Hao;Davison, William
本文综述了近20年来利用薄膜扩散梯度（DGT）研究化学形态的进展。DGT测量的动态溶液组分的理论评价提供了对DGT如何测量大多数金属络合物的理解，但排除了大多数胶体。这些发现加强了使用DGT作为监测工具，并提供了一个框架，使用DGT获得原位动力学信息。一般来说，DGT作为原位扰动和测量工具的能力尚未得到充分利用。在过去10年中，使用DGT来调查与生物利用度相关的过程的研究已经蓬勃发展，特别是对于土壤，因为DGT模拟了扩散限制吸收条件，在某些条件下，植物吸收。由于DGT积累的元素与植物体内元素的关系取决于植物种类、所研究的土壤、元素及其化学形态，因此DGT不是一个可靠的预测工具。相反，它的力量来自于提供系统中不稳定物种的信息，无论是水，土壤还是沉积物。最近的研究表明，在测量的金属在附着生物和DGT之间有很好的关系，并已获得统一的剂量响应曲线时，它们的基础上DGT测量沉积物中的生物。这两种情况都表明，替代既定的“自由离子”的方法可能是富有成效的，在这些媒体，并说明越来越多地使用DGT调查环境化学过程。
This review assesses progress in studies of chemical speciation using diffusive gradients in thin-films (DGT) by examining the contributions made by key publications in the last 20 years. The theoretical appreciation of the dynamic solution components measured by DGT has provided an understanding of how DGT measures most metal complexes, but excludes most colloids. These findings strengthen the use of DGT as a monitoring tool and provide a framework for using DGT to obtain in situ kinetic information. Generally, the capabilities of DGT as an in situ perturbation and measurement tool have yet to be fully exploited. Studies that have used DGT to investigate processes relevant to bioavailability have blossomed in the last 10 years, especially for soils, as DGT mimics the diffusion limiting uptake conditions that, under some conditions, characterise uptake by plants. As relationships between element accumulated by DGT and in plants depend on the plant species, soils studied, and the element and its chemical form, DGT is not an infallible predictive tool. Rather its strength comes from providing information on the labile species in the system, whether water, soil or sediment. Recent studies have shown good relationships between measurements of metals in periphyton and by DGT, and unified dose response curves have been obtained for biota in sediments when they are based on DGT measurements. Both these cases suggest that alternative approaches to the established ` free ion' approach may be fruitful in these media and illustrate the growing use of DGT to investigate environmental chemical processes.