Arsenic mobilization from historically contaminated mining soils in a continuously operated bioreactor: Implications for risk assessment

Liwia Rajpert, Boris A. Kolvenbach, Erik M. Ammann, Kerstin Hockmann, Maarten Nachtegaal, Elisabeth Eiche, Andreas Schäffer, Philippe Francois Xavier Corvini, Aleksandra Skłodowska, Markus Lenz*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

5 Citations (Scopus)

Abstract

Concentrations of soil arsenic (As) in the vicinity of the former Złoty Stok gold mine (Lower Silesia, southwest Poland) exceed 1000 μg g-1 in the area, posing an inherent threat to neighboring bodies of water. This study investigated continuous As mobilization under reducing conditions for more than 3 months. In particular, the capacity of autochthonic microflora that live on natural organic matter as the sole carbon/electron source for mobilizing As was assessed. A biphasic mobilization of As was observed. In the first two months, As mobilization was mainly conferred by Mn dissolution despite the prevalence of Fe (0.1 wt % vs 5.4 for Mn and Fe, respectively) as indicated by multiple regression analysis. Thereafter, the sudden increase in aqueous As[III] (up to 2400 μg L-1) was attributed to an almost quintupling of the autochthonic dissimilatory As-reducing community (quantitative polymerase chain reaction). The aqueous speciation influenced by microbial activity led to a reduction of solid phase As species (X-ray absorption fine structure spectroscopy) and a change in the elemental composition of As hotspots (micro X-ray fluorescence mapping). The depletion of most natural dissolved organic matter and the fact that an extensive mobilization of As[III] occurred after two months raises concerns about the long-term stability of historically As-contaminated sites.

Original languageEnglish
Pages (from-to)9124-9132
JournalEnvironmental Science and Technology
Volume50
Issue number17
DOIs
Publication statusPublished - 2016

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