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Abstract:
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Diffusive gradients in thin film (DGT ) technique is applied to determine pore water mercury concentrations in river sediments . DGT devices have been a useful indicator of dissolved metals in aqueous systems , although it is not as well developed for measuring mercury . DGT devices were evaluated for three different ion exchange resins for adsorption of mercury . After a series of laboratory experiments , 3 -Mercaptopropyl Functionalized Silica Gel (3M ) was chosen as an effective resin layer . Laboratory experiments showed that the resin strongly associated with dissolved Hg²⁺ . DGT probes were tested with sediments from the South River (Virginia , USA ) in the laboratory and the time dependent deployment verified an uptake of mercury to the probes and established an effective diffusion coefficient for site specific utilization . Multiple piston and sediment probes were deployed in the South River in -situ to determine overlying water Hg concentrations and sediment pore water Hg concentration profiles . The DGT devices were successful in measuring Hg concentrations in -situ . |