Morphodynamic conditions of heavy metal concentration in deposits of the Vistula River valley near Kępa Gostecka (central Poland)

The influence of morphodynamics of individual river valley zones on the anthropogenically induced distribution of heavy metals in the Małopolska Gorge of the Vistula River near Kępa Gostecka was studied. Based on the analysis of cartographic and geological mapping data, several floodplain features were distinguished. For each feature, lithological analysis of the deposits was carried out. It comprised determination of clay content, organic matter, carbonates and iron oxides and hydroxides, as well as analysis of heavy metal concentration. The investigations show that the concentration of heavy metals in floodplain surface deposits is strictly linked with the variability of depositional environments, which reflected in the intricate feature pattern. The highest contents of heavy metals have been found in the deposits of the contemporary floodplain, stagnation zones of floodwaters, oxbow lakes buried under floodplain or organic deposits and escarpment foot back swamps, while the lowest in deposits of the Pleistocene terrace and slope wash zones. Variability of floodwater dynamics modelling the floodplain surface is associated with the specific geological setting of the Vistula River valley stretch analysed.