Results of long-term sediment quality studies on the river Elbe

The results of long-term studies in the Upper and Middle Elbe River between 1991 and 2001 are presented and the temporal and spatial trends in sediment contamination and toxicity are studied. Although the concentrations of heavy metals and arsenic have significantly decreased in the last 10 years for most of the toxic elements they are still far from natural background values. For organic priority pollutants increasing as well as decreasing trends are observed, depending on the Elbe reach and/or the parameter under consideration. Elbe sediments have a permanent measurable toxicity. It is usually low in terms of aquatic tests as far as the persisting hot spots are not considered. Whole sediment testing with nematode Caenorhabditis elegans which was started in 1997 revealed clear toxic effects. In contrast to the priority pollution situation, no significant trend could be found in general sediment toxicity between 1992 and 2001.