Feasibility study to assess the ecotoxicological and toxicological impact on sediments as a result of the July 2021 flood in the transition from the low mountain range to the lowlands.

• Applicants: Dr.-Ing. Catrina Brüll; Professor Dr. Henner Hollert; Professor Dr. Jörg Oehlmann; Dr. Sabrina Schiwy; Dr. Frederic Strobl
• Subject Area: Hydrogeology, Hydrology, Limnology, Urban Water Management, Water Chemistry, Integrated Water Resources Management ; Geotechnics, Hydraulic Engineering ; Physical Geography
• Term: from 2021 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 497800446

Extreme flood events will increase in quantity and intensity in the next decades as a consequence of global climate change. Within the framework of the feasibility study applied for here, the toxicological hazards for the environment and humans associated with the extreme flood in July 2021 in Rhineland-Palatinate and North Rhine-Westphalia will be examined using a combination of Effect-based Methods (EBMs) and chemical analyses.The findings will be put into context with the results on previous sedimentological studies on pollutant loading from RWTH Aachen University as well as the recently approved ad-hoc-project on inorganic pollutant loading of sediments by the extreme flood on sedimentology and heavy metal analysis, in order to obtain as comprehensive a picture as possible of the extreme flood 2021, to identify further research questions and to develop a basis for future recommendations for prevention and action.For the first time it is possible to consider an event classified as a 10,000-year flood in Germany with regard to its ecotoxicological (for the environment) and human toxicological (for humans) potential. Immediately after the event, water, suspended sediment, and sediment samples, including sludge deposited in houses, were taken over a wide area in the study area and at strategic locations.The goal of the project is to investigate whether the July 2021 flood event represents a "Toxic Flood" associated with eco- and human toxicological impacts due to remobilization of polluted- sediments and new pollutant inputs.In detail, the following goals are defined: (i) Investigation of the input and mobilization of eco- and human-toxicologically effective organic pollutants during the extreme flood in July 2021;(ii) Investigation of ecotoxicological and human toxicological effects on sediments, suspended sediments and water samples of the extreme flood in July 2021; (iii) Identification of organic pollutants introduced by the flood and identification of drivers of the (eco)toxicological effects;(iv) Analyzing the temporal and spatial patterns for the transport of the organic pollutants and the (eco)toxicological effects and determining the importance for the process understanding of the transport of the pollutants in the complete catchment area during such an extreme event;(v) Drawing first conclusions on correlations and interactions between toxicological and sedimentological as well as hydrodynamic results

• DFG Programme: Research Grants