Studies on the transfer of heavy metals between sedimentary phases with a multi-chamber device: combined effects of salinity and redox

FSrstner, U., Ahlf, W. and Calmano, W., 1989. Studies on the transfer of heavy metals between sedimentary phases with a multi-chamber device: combined effects of salinity and redox vari-ation. Mar. Chem., 28: 145-158. Mobilization and transfer of heavy metals to major sediment components after changes of typ-ical estuarine conditions (salinity, redox potential/pH) have been studied in a newly developed experimental device, consisting of a central chamber connected with six external chambers and separated by membranes of0.45-~m pore diameter. Algal cell walls (Scenedesmus quadricauda), bentonite, Al-oxide, Mn-oxide, quartz powder and goethite were used as model sediment compo-nents. Significant metal enrichment was found on algal cell walls, and on freshly precipitated iron hydroxide. Oxidation of anoxic mud from Hamburg harbour causes lowering of pH and remobil-ization of cadmium and zinc. The experiments on the effect of seawater on sediment components and dredged mud indicate the dominant role of organic substrates in the binding of metals uch as cadmium and copper, suggesting that even at relatively small percentages of organic substrates these materials are primarily involved in metabolic processes and thus may constitute the major carriers by which metals are transferred within the food chain. These results demonstrate hat it is particularly problematic todisperse waste materials in ecologically productive, high-energy en-vironments such as estuaries