Impact of the 2024 flood event on trace elements contamination in floodplain sediments at the mouth of the Nysa Kłodzka river into the Odra valley

This study investigates the impact of the September 2024 flood on the trace elements concentration in the floodplain sediments at the mouth of the Nysa Kłodzka River into the Odra Valley. The research integrated geological mapping, sediment sampling (112 samples from 56 locations), laboratory analyses of trace element concentrations (44 representative samples from 22 locations), statistical evaluation (Mann-Whitney U test), and calculation of the geochemical and ecotoxicological indices (Enrichment Factor, Geoaccumulation Index, Contamination Factor, Degree of Contamination, Single Index of Ecological Risk Factor, Potential Ecological Risk Index). The results indicate that the 2024 flood event caused an increase in the concentrations of trace elements in surface sediments compared to subsurface, pre-flood layers (significant increase of Pb and Cd). The applied geochemical and ecotoxicological indices confirmed that the 2024 flood event enhanced both contamination levels and ecological risk in floodplain sediments. Overall, the findings emphase the important role of flood events in the mobilization, transport, and redistribution of contaminants within river floodplains.