Journal
ENVIRONMENTAL EARTH SCIENCES
Volume 59, Issue 1, Pages 25-38Publisher
SPRINGER
DOI: 10.1007/s12665-009-0001-0
Keywords
Groundwater discharge; Redox geochemistry; Trace metal migration; Sediment extraction; North Central Europe
Funding
- German Research Foundation (Deutsche Forschungsgemeinschaft) [546]
Ask authors/readers for more resources
The occurrence of trace metals was studied at the interface between groundwater and the drainage system of a large floodplain in NE Germany, the Oderbruch region. Depending on the predominant hydraulic connectivity between groundwater and the drainage channels, the geochemical environment creates a high variability in the accumulation of Fe, Mn, Cd, Zn, Cu, and As. The mobility of the trace metals depends on spatial variable redox transition zones which act as geochemical barriers between the anaerobe aquifer and the oxic surface waters. In drainage ditches with high exchange flow between groundwater and surface water the transition zone is small and unstable with a low retention potential for trace metals. Decreasing hydraulic gradients and respectively decreasing base flow cause the change for an extensive transition zone with increasing trace metal accumulation in the channel sediments. The accumulation is mainly controlled by oxidation and degassing of CO2. In the streambed sediments of channels which periodically run dry an effective chemical barrier can be observed. This Fe dominated oxic horizon controls the accumulation of Mn > Cu > As > Zn > Cd, which are mainly associated with fresh, amorphous Fe oxyhydroxides. The chemical barriers can be instable and reversible. Therefore, water management decisions are discussed which stabilize the barriers by controlling aquifer-channel exchange rates, channel oxygen content and surface water levels.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available