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Dissimilatory Iron-Reducing Microorganisms Are Present and Active in the Sediments of the Doce River and Tributaries Impacted by Iron Mine Tailings from the Collapsed Fundão Dam (Mariana, MG, Brazil)
| Content Provider | MDPI |
|---|---|
| Author | Keim, Carolina Serna, Jilder Acosta-Avalos, Daniel Neumann, Reiner Silva, Alex Jurelevicius, Diogo Pereira, Raphael de Souza, Pamella Seldin, Lucy Farina, Marcos |
| Copyright Year | 2021 |
| Description | On 5 November 2015, a large tailing deposit failed in Brazil, releasing an estimated 32.6 to 62 million m3 of iron mining tailings into the environment. Tailings from the Fundão Dam flowed down through the Gualaxo do Norte and Carmo riverbeds and floodplains and reached the Doce River. Since then, bottom sediments have become enriched in Fe(III) oxyhydroxides. Dissimilatory iron-reducing microorganisms (DIRMs) are anaerobes able to couple organic matter oxidation to Fe(III) reduction, producing CO2 and Fe(II), which can precipitate as magnetite (FeO·Fe2O3) and other Fe(II) minerals. In this work, we investigated the presence of DIRMs in affected and non-affected bottom sediments of the Gualaxo do Norte and Doce Rivers. The increase in Fe(II) concentrations in culture media over time indicated the presence of Fe(III)-reducing microorganisms in all sediments tested, which could reduce Fe(III) from both tailings and amorphous ferric oxyhydroxide. Half of our enrichment cultures converted amorphous Fe(III) oxyhydroxide into magnetite, which was characterized by X-ray diffraction, transmission electron microscopy, and magnetic measurements. The conversion of solid Fe(III) phases to soluble Fe(II) and/or magnetite is characteristic of DIRM cultures. The presence of DIRMs in the sediments of the Doce River and tributaries points to the possibility of reductive dissolution of goethite (α-FeOOH) and/or hematite (α-Fe2O3) from sediments, along with the consumption of organics, release of trace elements, and impairment of water quality. |
| Starting Page | 244 |
| e-ISSN | 2075163X |
| DOI | 10.3390/min11030244 |
| Journal | Minerals |
| Issue Number | 3 |
| Volume Number | 11 |
| Language | English |
| Publisher | MDPI |
| Publisher Date | 2021-02-26 |
| Access Restriction | Open |
| Subject Keyword | Minerals Water Science and Technology Rio Doce Gualaxo Do Norte Mariana Fundão Dam Tailings Bottom Sediments Dissimilatory Iron-reducing Bacteria Goethite Hematite Magnetite |
| Content Type | Text |
| Resource Type | Article |
