Metal pollution in the tidal Elbe River

Abstract

Studies of water, suspended particulate matter, and sediment chemistry and mineralogy from longitudinal sections of the Elbe River estuary indicate that the distribution of metal pollutants is predominantly influenced by the mixing of marine and fluvial sediments, but occurs far upstream of the salinity gradient. Water discharge and, to a lesser extent, wind stress typically affect the transfer rates of fine-grained polluted solids into the outer estuary. From field investigations, significant mobilization has only been observed for cadmium. Release of cadmium from solids into the water phase seems to be caused by the combined effects of oxidation and increasing salinity. Quantitative treatment of metal transport is performed by numerical simulation based on representative field data (BILEX Project of GKSS). Experimental laboratory studies on contaminated sediments from Hamburg Harbour using a six-chamber device indicate characteristic transfer mechanisms into organic substrates even at relatively small rates of metal release. Future investigations on metal pollution will increasingly consider biological interactions. For the 3-year period (1989–1991) of the “Special Research Project — Tidal Elbe River”, focus will be on studies of mesocosms. Remote-measurements from the EC Project “MERMAID” will provide permanent records of meteorological, oceanographic and chemical parameters.