Fast colloidal and dissolved release of trace elements in a carbonatic soil after experimental flooding

Many floodplains worldwide are contaminated with a variety of potentially toxic trace metals. The flooding of such plains causes decreases of the soil redox potential and strongly affects the mobility of stored metals. We conducted a 40-day incubation experiment by flooding a carbonatic soil in a microcosm and determining Eh, pH, H2S, organic and inorganic C, ion composition, and metal concentrations in bulk soil solution ( 80%; 0.02–10 μm). With continued flooding, partitioning of metals in the soil solid phase changed and a larger fraction of the total metal concentrations became exchangeable, i.e. bioavailable. We demonstrate markedly different release patterns for two different groups of trace metals and significant changes in metal partitioning in the soil solid phase in response to artificial flooding