Bestimmung von Konzentrationsgradienten gelöster Schwermetalle an der Sediment/Wasser-Grenzfläche mit Hilfe der Dialysetechnik

Laboratory and field evaluations were made of a diffusion-controlled sampler which incorporates a 0.2-μm polycarbonate membrane to filter pore water samples in situ. Sample ports at 1-cm intervals were exposed both above and beneath the sediment-water interface enabling determination of geochemical gradients and dissolved metal profiles at the interface. Gradients obtained for ions whose concentrations are controlled by redox processes in the sediment column were not consistent with those determined from interstitial water by squeezing of adjacent sediment. The diffusive flux of dissolved metal species across the sediment-water interface can be assessed more accurately using this sampler than by data collected from conventional benthic cores.