Hydrotoxikologie - Entwicklung einer experimentellen Methodik zur Charakterisierung und Bewertung kohäsiver schadstoffbehafteter fluvialer Sedimente

Erosion and resuspension can be induced by flood and maintaining events in rivers and on flood-plains. Contaminated sediments that are transported in the water column can pose a risk for aquatic organisms. Especially the erosion and resuspension of cohesive sediments can bond contami-nants.The sediment composition decides which contaminants (e.g. organic compounds, heavy metal) is bond. When describing and evaluating river sections aspects like hydro dynamic, rheology and ecotoxicology need to be considered. These aspects can be assigned to the research fields civil engineering (hydraulic and water resources engineering) and biology (ecotoxicology). It is clear that an interdisciplinary problem is to be addressed that cannot be answered by established methods. Hence, the newly developed hydrotoxicological methodology is introduced in this work. In the methodology, the two named research fields are experimentally linked. This allows a holistic and integrated evaluation of interested areas.Bioavailability and bioaccessibility of contaminants depends on a variety of different parameters. Their relevance as well as resulting processes and interactions are currently not known and understood; hence a description is not possible. Involved parameters are for instance sediment type, concentration of contamination, aquatic ecosystems and variable environmental conditions. In order to identify the relevance of the parameters, it is indispensable to define and evaluate a differentiated are of interest. The identified parameters are assigned to parameter groups to allow comparability. The five parameter groups are: sediments, organism, hydrodynamics, contaminants and environmental conditions.The hydrotoxicological methodology starts with a theoretical description of the area of interest in order to identify involved parameters for a following evaluation. An experimental approach is sued to identify processes and interaction of parameters during erosion. Hydrotoxicology concentrates on considering relevant parameters and their detailed data logging. This is necessary for a quantitative description of resulting processes and interactions. The implementation of Hydrotoxicology takes place in an annular flume which is a specific test facility to investigate transport and erosion of cohesive sediments. The instrumentation of the annular flume was improved to meet the conditions of interdisciplinary conduced experiment. Within this optimization an air supply for exposed fish and a pH-control-system were installed.In order to define the relevance of considered parameters as well as resulting processes and interac-tions, collected data needs to be analyzed. First, the data is analyzed under monodisciplinary aspects and in a second step under interdisciplinary aspects. The realization of Hydrotoxicology was success-fully proved with the first experiments. The methodology is suitable to characterize and to evaluate cohesive, contaminated and fluvial sediments