Applications of DGT in coastal sediments: monitoring and biogeochemical study of trace metals and oxyanions

Diffusive gradients in thin films (DGT) is a powerful analytical tool that has been widely used to obtain concentration and distribution data of target analytes in waters, soils, and sediments. While many review papers have discussed the development and application of DGT, there has been no comprehensive review specifically focusing on its use in coastal sediments, which are subject to complex and diverse environmental conditions and can be easily affected by anthropogenic activities. Coastal sediments can act as a source or a sink of trace metals and oxyanions to the overlying water, making it essential to use analytical methods with high resolution and selectivity. This paper provides a thorough review of the research applications of DGT in coastal sediments, including nearshore, estuarine, and intertidal sediments. The review also presents a brief introduction to DGT devices and deployment methods in coastal sediment environments and discusses in details the reported cases of DGT application since 2010, which include metal and oxyanion mobilization and interaction, pollutant monitoring and risk assessment, diagenetic processes, as well as the kinetics and mechanism of analyte transfer across the sediment-water interface. Finally, the review discusses the expected future progress of DGT technique.