Vertical distribution and speciation of trace metals in weathering flotation residues of a zinc/lead sulfide mine

Autor(en)

Nele Schuwirth, Andreas Voegelin, Ruben Kretzschmar, Thilo Hofmann

Abstrakt

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(en)

Externe Organisation(en)

Johannes Gutenberg-Universität Mainz, Eidgenössische Technische Hochschule Zürich

Journal

Journal of Environmental Quality

Band

36

Seiten

61-69

Anzahl der Seiten

9

ISSN

0047-2425

Publikationsdatum

2007

Peer-reviewed

Ja

ÖFOS 2012

104023 Umweltchemie, 105904 Umweltforschung

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/3a913778-5e9c-4c41-8d4f-1db7121ed0d8