Near surface halogen (F, Cl, Br, I) cycle
Final Report Abstract
The halogen distribution in secondary Pb-minerals and the fate of the halogens (F, Cl, Br and I) in the critical zone, including the pedosphere and the hydrological flow path were investigated in this project. The results revealed that the halogen cycle is controlled by a complex interaction of biotic and abiotic processes and that these processes differ for each halogen. Accumulation of Cl in the topsoil could be shown to be caused by chlorination processes and nutrient uplift by roots. The cycling of F, Br and I was rather controlled by pH-related weathering and high solubility in combination with sorption processes to pedogenic oxides or incorporation into clay minerals. Furthermore, it was shown that also vegetation and soil external processes such as atmospheric halogen input had an influence on halogen composition along the hydrological flow path, due to the wash-off of dry deposition and foliage leaching. Last but not least, the investigation of secondary Pb-minerals revealed that the halogen distribution within individual growth zones is strongly dependent on fluid composition.
Publications
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Crystallographic and fluid compositional effects on the halogen (Cl, F, Br, I) incorporation in pyromorphite-group minerals. American Mineralogist, 104(11), 1673-1688.
Epp, Tatjana; Marks, Michael A.W.; Ludwig, Thomas; Kendrick, Mark A.; Eby, Nelson; Neidhardt, Harald; Oelmann, Yvonne & Markl, Gregor
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Vegetation canopy effects on total and dissolved Cl, Br, F and I concentrations in soil and their fate along the hydrological flow path. Science of The Total Environment, 712, 135473.
Epp, Tatjana; Neidhardt, Harald; Pagano, Norina; Marks, Michael A.W.; Markl, Gregor & Oelmann, Yvonne
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Halogen (F, Cl, Br, I) contents in silt and clay fractions of a Cambisol from a temperate forest. American Mineralogist, 107(5), 946-954.
Epp, Tatjana; Marks, Michael A.W.; Neidhardt, Harald; Oelmann, Yvonne & Markl, Gregor
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Impact of abiotic and biogeochemical processes on halogen concentrations (Cl, Br, F, I) in mineral soil along a climatic gradient. Environmental Science: Processes & Impacts, 24(9), 1330-1342.
Neidhardt, Harald; Lemke, Erik; Epp, Tatjana; Marks, Michael A. W.; Markl, Gregor & Oelmann, Yvonne
