Vertical distribution and speciation of trace metals in weathering flotation residues of a zinc/lead sulfide mine
- Author(s)
- Nele Schuwirth, Andreas Voegelin, Ruben Kretzschmar, Thilo Hofmann
- Abstract
Sulfide-bearing mine tailings are a serious environmental problem around the world. In this study, the vertical distribution and speciation of Zn and Pb in the fine-grained flotation residues of a former sulfide ore mine in Germany were investigated to assess the inorganic weathering processes that effect the environmental risk arising from this site. Total metal contents were determined by X-ray fluorescence spectroscopy (XRF). Mobilizable fractions of Zn, Pb, Fe, and Mn were quantified by sequential chemical extractions (SCE). Furthermore, the speciation of Zn was analyzed by Zn K-edge extended X-ray absorption fine structure spectroscopy (EXAFS) to identify the residual Zn species. The variations in pH and inorganic C content show an acidification of the topsoil to pH 5.5. EXAFS results confirm that Zn is mainly bound in sphalerite in the subsoil and weathering reactions lead to a redistribution of Zn in the topsoil. A loss of 35% Zn and S from the topsoil compared with the parent material with 10 g kg-1 Zn and neutral pH has been observed. If acidification proceeds it will lead to a significant release of Zn, S, and Pb to the ground water. In contrast to Zn, Pb is enriched in the mobile fraction of the topsoil by more than a factor of two compared with the subsoil which contains a total of 2 g kg-1 Pb. Thus, the high bioavailability of Pb and the potential for Pb uptake by plants and animals currently represent the most severe threat for environmental health.
- Organisation(s)
- External organisation(s)
- Johannes Gutenberg-Universität Mainz, Eidgenössische Technische Hochschule Zürich
- Journal
- Journal of Environmental Quality
- Volume
- 36
- Pages
- 61-69
- No. of pages
- 9
- ISSN
- 0047-2425
- Publication date
- 2007
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 104023 Environmental chemistry, 105904 Environmental research
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/3a913778-5e9c-4c41-8d4f-1db7121ed0d8