In search for the ecological and toxicological relevance of sediment re-mobilisation and transport during flood events

Abstract

In response to increasing concerns about the potential toxicological impacts of (extreme) flood events, scientists from several disciplines have joined to form the interdisciplinary research project named FLOODSEARCH. FLOODSEARCH is one of the recent Pathfinder Projects supported by the German Excellence Initiative via the Exploratory Research Space at RWTH Aachen (ERS). FLOODSEARCH aims to combine methodologies of hydraulic engineering and ecotoxicology in a new interdisciplinary approach to assess the risks associated with the re-mobilisation of particulate bound contaminants often observed after severe flood events. Impacts of extreme flood events and aspects of re-mobilisation of sediment-bound toxic compounds will be characterised and evaluated in controlled experiments fusing flood simulation technologies with biological effects assessment. The overall goal is to establish a novel and more realistic approach towards flood event testing that can be applied to a number of different questions and species. Specifically, model aquatic species such as rainbow trout (Onchorhynchus mykiss) will be exposed to particle-bound contaminants in flood-like conditions in a specifically designed annular flume that permits monitoring of both physical/chemical and biological parameter. Ultimately, this approach will assist to further our understanding of the potential biological risks associated with increasingly frequent extreme flood events, e.g., as a consequence of climate change, by bridging the gap between the physical (re-)mobilisation of contaminants and resulting toxicological impacts on aquatic organisms. Thus, it is the objective of the project to derive relationships between the hydrodynamic parameters such as velocities and turbulences, the parameters associated to sediment transport such as sediment concentration and grain sizes and the biological parameters.