No abstract

No abstract

No abstract

No abstract

Floodplain soils are often contaminated with toxic elements such as Ba, Cr, Sr, and V. For an adequate risk assessment of such contaminated sites, the assessment of factors affecting the leaching of those elements from riverine soils into water is fundamental. Since the redox potential (E-H) can be important within this context, we aimed to assess the impact of pre-set redox conditions on the dynamics of Ba, Cr, Sr, and V in a floodplain soil. To achieve this aim, we used an automatic biogeochemical microcosm system allowing computer-controlled regulation of E-H by adapting the supply of N-2 or O-2 to the soil suspension. With this system, the effect of E-H on the dynamics of Ba, Cr, Sr, and V was studied mechanistically. Chromium and V were negatively correlated with E-H possibly due to co-precipitation of these metals with Fe (hydr)oxides at high E-H. Vanadium might additionally be oxidized from more soluble V(IV) to less soluble V(V) with rising E-H. Barium and Sr were positively correlated with E-H, which might be attributed to their association with dissolved organic carbon (DOC). The influence of pH on the dynamics of the studied elements seemed to be of minor importance in our study. A significant negative correlation was observed between the specific UV absorbance at 254 nm (SUVA (254)) and E-H indicating that oxidizing conditions favored the removal of aromatic DOC molecules from solution via binding to Fe (hydr)oxides. Redox potential is important for metal fate in the current study. Results imply an absorption of Cr and V to Fe (hydr)oxides and an interaction with DOC while particularly Ba and Sr dynamics may be influenced by DOC. In the future, different V species in wetland soils under pre-definite redox conditions should be determined and further studies should elucidate the specific role of DOC and sulfur (S) chemistry on the dynamics of the studied metals

No abstract

No abstract

No abstract