University of Oulu

Kujala, K., Besold, J., Mikkonen, A., Tiirola, M. and Planer‐Friedrich, B. (2020), Abundant and diverse arsenic‐metabolizing microorganisms in peatlands treating arsenic‐contaminated mining wastewaters. Environ Microbiol, 22: 1572-1587. doi:10.1111/1462-2920.14922

Abundant and diverse arsenic‐metabolizing microorganisms in peatlands treating arsenic‐contaminated mining wastewaters

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Author: Kujala, Katharina1; Besold, Johannes2; Mikkonen, Anu3;
Organizations: 1Water Resources and Environmental Engineering Research Unit, University of Oulu, Oulu, Finland
2Environmental Geochemistry, Bayreuth Center for Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
3Department of Biological and Environmental Science, Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.5 MB)
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Language: English
Published: John Wiley & Sons, 2020
Publish Date: 2020-06-05


Mining operations produce large quantities of wastewater. At a mine site in Northern Finland, two natural peatlands are used for the treatment of mining‐influenced waters with high concentrations of sulphate and potentially toxic arsenic (As). In the present study, As removal and the involved microbial processes in those treatment peatlands (TPs) were assessed. Arsenic‐metabolizing microorganisms were abundant in peat soil from both TPs (up to 108 cells gdw−1), with arsenate respirers being about 100 times more abundant than arsenite oxidizers. In uninhibited microcosm incubations, supplemented arsenite was oxidized under oxic conditions and supplemented arsenate was reduced under anoxic conditions, while little to no oxidation/reduction was observed in NaN3‐inhibited microcosms, indicating high As‐turnover potential of peat microbes. Formation of thioarsenates was observed in anoxic microcosms. Sequencing of the functional genemarkers aioA (arsenite oxidizers), arrA (arsenate respirers) and arsC (detoxifying arsenate reducers) demonstrated high diversity of the As‐metabolizing microbial community. The microbial community composition differed between the two TPs, which may have affected As removal efficiencies. In the present situation, arsenate reduction is likely the dominant net process and contributes substantially to As removal. Changes in TP usage (e.g. mine closure) with lowered water tables and heightened oxygen availability in peat might lead to re‐oxidation and re‐mobilization of bound arsenite.

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Series: Environmental microbiology
ISSN: 1462-2912
ISSN-E: 1462-2920
ISSN-L: 1462-2912
Volume: 22
Issue: 4
Pages: 1572 - 1587
DOI: 10.1111/1462-2920.14922
Type of Publication: A1 Journal article – refereed
Field of Science: 1172 Environmental sciences
218 Environmental engineering
Funding: Funding for this work was provided by the Academy of Finland (Project 287397 ‘Microbial transformations of arsenic and antimony in Northern natural peatlands treating mine waste waters’). Additional support was provided by the European Research Council (ERC grant awarded to MT, Grant Agreement No. 615146, FP/2007‐2013), the Bavarian Funding Program for the Initiation of International Projects and the German Research Foundation (grants awarded to BPF, BayIntAn_UBT_2017_23 and DFG PL 302/20‐1).
Academy of Finland Grant Number: 287397
Detailed Information: 287397 (Academy of Finland Funding decision)
Copyright information: © 2020 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.