title: Effect of redox conditions on MTBE biodegradation in surface water sediments.
abstract: Microbial degradation of methyl tert-butyl ether (MTBE) was observed in surface water-sediment microcosms under anaerobic conditions. The efficiency and products of anaerobic MTBE biodegradation were dependent on the predominant terminal electron-accepting conditions. In the presence of substantial methanogenic activity, MTBE biodegradation was nominal and involved reduction of MTBE to the toxic product, tert-butyl alcohol (TBA). In the absence of significant methanogenic activity, accumulation of [14C]TBA generally decreased, and mineralization of [U-14C]MTBE to 14CO2 generally increased as the oxidative potential of the predominant terminal electron acceptor increased in the order of SO4, Fe(III), Mn(IV) < NO3 < O2. Microbial mineralization of MTBE to CO2 under Mn(IV)-or SO4-reducing conditions has not been reported previously. The results of this study indicate that microorganisms inhabiting the sediments of streams and lakes can degrade MTBE effectively under a range of anaerobic terminal electron-accepting conditions. Thus, anaerobic bed sediment microbial processes may provide a significant environmental sink for MTBE in surface water systems throughout the United States.
authors.affiliation: US Geological Survey, Columbia, South Carolina 29210-7651, USA. pbradley@usgs.gov
authors.forename: P M
authors.initials: PM
authors.lastname: Bradley
authors.forename: F H
authors.initials: FH
authors.lastname: Chapelle
authors.forename: J E
authors.initials: JE
authors.lastname: Landmeyer
mesh_terms: D001421:Bacteria, Anaerobic / Q000502:physiology*; D001673:Biodegradation, Environmental; D002245:Carbon Dioxide / Q000737:chemistry; D002273:Carcinogens / Q000378:metabolism*; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry*; D008738:Methyl Ethers / Q000378:metabolism*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry
chemical_list: D002273:Carcinogens; D008738:Methyl Ethers; D002245:Carbon Dioxide; C043243:methyl tert-butyl ether; D010100:Oxygen