Release of trace elements during bioreductive dissolution of magnetite from metal mine tailings: Potential impact on marine environments

Autor: Bernhard Dold, Robert Benaiges-Fernandez, Jordi Cama, Jordi Palau, Jordi Urmeneta, Josep M. Soler, Francesco G. Offeddu
Přispěvatelé: Ministerio de Ciencia e Innovación (España), Cama, Jordi [0000-0002-8949-3088], Cama, Jordi
Rok vydání: 2021
Předmět:
Zdroj: Digital.CSIC: Repositorio Institucional del CSIC
Consejo Superior de Investigaciones Científicas (CSIC)
Digital.CSIC. Repositorio Institucional del CSIC
instname
Dipòsit Digital de la UB
Universidad de Barcelona
ISSN: 1879-1026
Popis: Adverse impacts of mine tailings on water and sediments quality are major worldwide environmental problems. Due to the environmental issues associated with the deposition of mine tailings on land, a controversial discussed alternative is submarine tailings disposal (STD). However, Fe(III) bioreduction of iron oxides (e.g., magnetite) in the tailings disposed might cause toxic effects on coastal environments due to the release of different trace elements (TEs) contained in the oxides. To study the extent and kinetics of magnetite bioreduction under marine conditions and the potential release of TEs, a number of batch experiments with artificial seawater (pH 8.2) and a marine microbial strain (Shewanella loihica) were performed using several magnetite ore samples from different mines and a mine tailings sample. The elemental composition of the magnetite determined in the tailings showed relatively high amounts of TEs (e.g., Mn, Zn, Co) compared with those of the magnetite ore samples (LA-ICP-MS and EMPA analyses). The experiments were conducted at 10 °C in the dark for up to 113 days. Based on the consumption of lactate and production of acetate and aqueous Fe(II) over time, the magnitude of Fe(III) bioreduction was calculated using a geochemical model including Monod kinetics. Model simulations reproduced the release of iron and TEs observed throughout the experiments, e.g., Mn (up to 203 μg L−1), V (up to 79 μg L−1), As (up to 17 μg L−1) and Cu (up to 328 μg L−1), suggesting a potential contamination of pore water by STD. Therefore, the results of this study can help to better evaluate the potential impacts of STD.
Thanks are due to Jordi Bellés (IDAEA-CSIC) for technical assistance in the laboratory and to Prof. Carlos Ayora (IDAEA-CSIC) for the fruitful discussions on the geochemical model implementation. Technical and human support provided by the Geochronology and Isotope Geochemistry-SGIker facility (UPV/EHU, MINECO, GV/EJ, ERDF and ESF) is gratefully acknowledged. This study was funded by the Chilean Government through the Research Fund for Fishery and Aquaculture (Fondo de Investigación Pesquera y de Acuicultura; FIPA) of SUBPESCA (FIP 2015-11 project), the Spanish Ministries of Economy and Competitiveness and Science and Innovation with contribution of FEDER funds (CGL2017–82331-R and CEX2018-000794-S projects), and the Catalan Government (2017SGR 1733 project). We thank the three anonymous reviewers whose comments and suggestions contributed to improve the quality of the manuscript.
Databáze: OpenAIRE
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