Historical roasting of thallium- and arsenic-bearing pyrite: Current Tl pollution in the Riotinto mine area.
- López-Arce P Museo Nacional de Ciencias Naturales (CSIC), C/José Gutiérrez Abascal, 2, 28026 Madrid, Spain.
- Garrido F Museo Nacional de Ciencias Naturales (CSIC), C/José Gutiérrez Abascal, 2, 28026 Madrid, Spain. Electronic address: fernando.garrido@mncn.csic.es.
- García-Guinea J Museo Nacional de Ciencias Naturales (CSIC), C/José Gutiérrez Abascal, 2, 28026 Madrid, Spain.
- Voegelin A Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Water Resources and Drinking Water, Überlandstrasse 133, CH-8600 Dübendorf, Switzerland.
- Göttlicher J Karlsruhe Institute of Technology, Institute for Photon Science and Synchrotron Radiation, KIT Campus North, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany.
- Nieto JM Department of Earth Sciences, University of Huelva, 21071 Huelva, Spain.
- 2018-10-21
Published in:
- The Science of the total environment. - 2019
English
Samples of an open-air pyrite roasting heap from the 19th century in the Riotinto mine area (SW Spain) and surrounding sediments and soil along a seasonal surface runoff channel were analyzed to study thallium (Tl) phase transformations during historical roasting of Tl-bearing arsenian pyrite, secondary weathering processes, Tl dispersion and current environmental pollution. Results from Electron Probe Microanalyses (EPMA) indicate an even distribution of Tl in pyrite grains of an ore sample (22 mg kg-1 total Tl), suggesting that Tl is incorporated in the pyrite structure rather than in discrete Tl-sulfide microparticles. The roasting residue (122 mg kg-1 total Tl) consists mainly of hematite. EPMA suggested that Tl in the roasting residue and contaminated soil was co-occurring with Fe oxide particles, with a mean Tl point concentration of 0.12% in samples from the roasting residues. Total concentrations of Tl in soil samples decrease with distance from the roasting heap to 14 mg kg-1. X-ray absorption near-edge structure (XANES) spectra collected on pyrite roasting residue and a soil sample suggest that most Tl is Tl(I) substituting K in jarosite. Sequential extractions show that most Tl (85-99%) in the soil and sediment samples is concentrated in the residual fraction and, thus, is rather strongly bound. Lastly, water extracts indicate that colloidal particles (i.e. <1 μm size) may contribute to the dispersion of Tl around and away from the roasting heaps.
- Language
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- English
- Open access status
- green
- Identifiers
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- DOI 10.1016/j.scitotenv.2018.08.260
- PMID 30340272
- Persistent URL
- https://sonar.ch/global/documents/156112
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