In situ high-resolution evaluation of labile arsenic and mercury in sediment of a large shallow lake

The principle of DGT is based on the diffusion of dissolved species through a well-defined gel and subsequent accumulation on an ion-exchange resin. A diffusion gel and a filter membrane (to protect the gel) are commonly used as the diffusive layer. The resin gel, which serves as a binding agent, is incorporated into a second polyacrylamide gel. The concentrations of the target elements are measured, including the fractions in pore water near the device surface and the fractions resupplied from solution, as well as that continuously released from the sediments.111