Role of microbial processes in arsenic cycling

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dc.contributor.advisor Kappler, Andreas (Prof. Dr.) Glodowska, Martyna, Aleksandra 2020-07-10T05:32:09Z 2020-07-10T05:32:09Z 2022-06-30
dc.identifier.uri de_DE
dc.description.abstract Dissertation ist gesperrt bis 30. Juni 2022 ! de_DE
dc.description.abstract Arsenic (As) is a toxic metalloid of geogenic origins that can lead to groundwater contamination and serious health consequences. South and Southeast Asia, the most populated regions of the world, are particularly affected as the access to water treatment facilities is limited and many people, mainly in rural areas still rely on shallow groundwater wells. Various mechanisms of As release to the groundwater have been suggested to date. Yet, the most commonly accepted one is that As is released from aquifer sediments during microbially-mediated reductive dissolution of As-bearing Fe(III) (oxyhydr)oxide minerals. This process, however, requires the presence of bioavailable carbon (C) that Fe(III)-reducing microorganisms need as energy, electron and carbon sources for their activity. Most laboratory studies, however, used simple fatty acids or sugars, often at high and not environmentally relevant concentrations, instead of naturally-occurring organic matter (OM). Therefore, in this work extracted in-situ OM was characterized (FTIR, NMR, EEM and Pyrolysis GC/MS), and used in 100-day microcosm experiments to determine Fe(III) mineral reduction, As mobilization and the microbial community composition compared to easily bioavailable fatty acids. Furthermore, this work explored the potential of single C compound such as methane (CH4) as the electron donor and driver of reductive dissolution of Fe- and As-bearing sediments. This work for the first time demonstrated that CH4, widely abundant in many As contaminated aquifers across South and Southeast Asia, can be efficiently used by methanotrophic archaea such as Candidatus Methanoperedens to reduce Fe(III) and consequently mobilize As to groundwater. Finally, this PhD thesis revealed main microbial processes occurring in As contaminated aquifer in Vietnam. Some of these process such as SO42- reduction, Fe(III) reduction, Fe2+ oxidation or methanotrophy can directly affect the fate of As in groundwater. Other processes that were found dominant in situ such as methanogenesis and fermentation indirectly favor As mobilization by providing wide range of electron donors. Overall this PhD thesis broadened our understanding of As biogeochemical cycling and filled some knowledge gaps about microbial contribution to this cycle. en
dc.language.iso en de_DE
dc.publisher Universität Tübingen de_DE
dc.rights ubt-podok de_DE
dc.rights.uri de_DE
dc.rights.uri en
dc.subject.classification Arsen , Methan , Grundwasser , Kontamination , Grundwasserleiter de_DE
dc.subject.ddc 000 de_DE
dc.subject.ddc 333.7 de_DE
dc.subject.ddc 500 de_DE
dc.title Role of microbial processes in arsenic cycling en
dc.type Dissertation de_DE
dcterms.dateAccepted 2020-06-30
utue.publikation.fachbereich Geographie, Geoökologie, Geowissenschaft de_DE
utue.publikation.fakultaet 7 Mathematisch-Naturwissenschaftliche Fakultät de_DE
utue.publikation.source de_DE
utue.publikation.noppn yes de_DE


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