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Microbial degradation of methyl tert-butyl ether and tert-butyl alcohol in the subsurface 总被引:16,自引:0,他引:16
The fate of fuel oxygenates such as methyl tert-butyl ether (MTBE) in the subsurface is governed by their degradability under various redox conditions. The key intermediate in degradation of MTBE and ethyl tert-butyl ether (ETBE) is tert-butyl alcohol (TBA) which was often found as accumulating intermediate or dead-end product in lab studies using microcosms or isolated cell suspensions. This review discusses in detail the thermodynamics of the degradation processes utilizing various terminal electron acceptors, and the aerobic degradation pathways of MTBE and TBA. It summarizes the present knowledge on MTBE and TBA degradation gained from either microcosm or pure culture studies and emphasizes the potential of compound-specific isotope analysis (CSIA) for identification and quantification of degradation processes of slowly biodegradable pollutants such as MTBE and TBA. Microcosm studies demonstrated that MTBE and TBA may be biodegradable under oxic and nearly all anoxic conditions, although results of various studies are often contradictory, which suggests that site-specific conditions are important parameters. So far, TBA degradation has not been shown under methanogenic conditions and it is currently widely accepted that TBA is a recalcitrant dead-end product of MTBE under these conditions. Reliable in situ degradation rates for MTBE and TBA under various geochemical conditions are not yet available. Furthermore, degradation pathways under anoxic conditions have not yet been elucidated. All pure cultures capable of MTBE or TBA degradation isolated so far use oxygen as terminal electron acceptor. In general, compared with hydrocarbons present in gasoline, fuel oxygenates biodegrade much slower, if at all. The presence of MTBE and related compounds in groundwater therefore frequently limits the use of in situ biodegradation as remediation option at gasoline-contaminated sites. Though degradation of MTBE and TBA in field studies has been reported under oxic conditions, there is hardly any evidence of substantial degradation in the absence of oxygen. The increasing availability of field data from CSIA will foster our understanding and may even allow the quantification of degradation of these recalcitrant compounds. Such information will help to elucidate the crucial factors of site-specific biogeochemical conditions that govern the capability of intrinsic oxygenate degradation. 相似文献
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Pamela R. D. Williams 《Environmental Forensics》2014,15(1):97-119
Potential threats to drinking water and water quality continue to be a major concern in many regions of the United States. New Jersey, in particular, has been at the forefront of assessing and managing potential contamination of its drinking water supplies from hazardous substances. The purpose of the current analysis is to provide an up-to-date evaluation of the occurrence and detected concentrations of methyl tertiary butyl ether (MTBE) and several other volatile organic compounds (VOCs) in public water systems, private wells, and ambient groundwater wells in New Jersey based on the best available data, and to put these results into context with federal and state regulatory and human-health benchmarks. Analyses are based on the following three databases that contain water quality monitoring data for New Jersey: Safe Drinking Water Information System (SDWIS), Private Well Testing Act (PWTA), and National Water Information System (NWIS). For public water systems served by groundwater in New Jersey, MTBE was detected at a concentration ≥10 μg/L, ≥20 μg/L, and ≥70 μg/L at least once in 30 (2%), 21 (1.4%), and five (0.3%) of sampled systems from 1997 to 2011, respectively. For private wells in New Jersey, MTBE was detected at a concentration ≥10 μg/L, ≥20 μg/L, and ≥70 μg/L at least once in 385 (0.5%), 183 (0.2%), and 46 (0.05%) of sampled wells from 2001 to 2011, respectively. For ambient groundwater wells in New Jersey, MTBE was detected at a concentration ≥10 μg/L, ≥20 μg/L, and ≥70 μg/L at least once in 14 (2.1%), 9 (1.3%), and 4 (0.6%) of sampled wells from 1993 to 2012, respectively. Average detected concentrations of MTBE, as well as detected concentrations at upper-end percentiles, were less than corresponding benchmarks for all three datasets. The available data show that MTBE is rarely detected in various source waters in New Jersey at a concentration that exceeds the State's health-based drinking water standard or other published benchmarks, and there is no evidence of an increasing trend in the detection frequency of MTBE. Other VOCs, such as tetrachloroethylene (PCE), trichloroethylene (TCE), and benzene, are detected more often above corresponding regulatory or human-health benchmarks due to their higher detected concentrations in water and/or greater toxicity values. The current analysis provides useful data for evaluating the nature and extent of historical and current contamination of water supplies in New Jersey and potential opportunities for public exposures and health risks due to MTBE and other VOCs on a statewide basis. Additional forensic or forecasting analyses are required to identify the sources or timing of releases of individual contaminants at specific locations or to predict potential future water contamination in New Jersey. 相似文献
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A method was developed to determine the concentration of methyl tert-butyl ether(MTBE) in gasoline,diesel and heating oil by gas chromatography(GC) with mass spectrometry(GC-MS) or flame ionization detection(FID). The diluted gasoline was directly injected into the GC, and the complete separation of MTBE from co-eluting hydrocarbons was not required. GC/MS or GC/FID method can be used to analyze MTBE in different concentration range and have good consistency. 相似文献
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加油站渗漏污染地下水已经是一个世界性的问题。由于浅埋区加油站储罐与地下水密切接触,更加剧储罐的腐蚀。为揭示加油站渗漏的典型污染物石油烃(TPH)、苯系物(BTEX)、萘和甲基叔丁基醚(MTBE)在该水文地质条件下的迁移变化,在浅埋区某加油站开展了平、枯、丰水期的地下水监测工作。在水平分布上,TPH、BTEX、萘基本相似,均在加油岛附近形成高浓度区,而MTBE则更易随地下水流动而迁移,呈现出不同的污染晕。在垂直分布上,地下水的水位变动是污染物浓度分布的主要影响因素。 相似文献
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Emerging water contaminants derived from unleaded gasoline such as methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME), are in need of effective bioremediation technologies for restoring water resources. In order to design the conditions of a future groundwater bioremediating biofilter, this work assesses the potential use of Acinetobacter calcoaceticus M10, Rhodococcus ruber E10 and Gordonia amicalis T3 for the removal of MTBE, ETBE and TAME in consortia or as individual strains. Biofilm formation on an inert polyethylene support material was assessed with scanning electron microscopy, and consortia were also analysed with fluorescent in situ hybridisation to examine the relation between the strains. A. calcoaceticus M10 was the best coloniser, followed by G. amicalis T3, however, biofilm formation of pair consortia favoured consortium M10-E10 both in formation and activity. However, degradation batch studies determined that neither consortium exhibited higher degradation than individual strain degradation. The physiological state of the three strains was also determined through flow cytometry using propidium iodide and 3′-dihexylocarbocyanine iodide thus gathering information on their viability and activity with the three oxygenates since previous microbial counts revealed slow growth. Strain E10 was observed to have the highest physiological activity in the presence of MTBE, and strain M10 activity with TAME was only maintained for 24 h, thus we believe that biotransformation of MTBE occurs within the active periods established by the cytometry analyses. Viable cell counts and oxygenate removal were determined in the presence of the metabolites tert-butyl alcohol (TBA) and tert-amyl alcohol (TAA), resulting in TBA biotransformation by M10 and E10, and TAA by M10. Our results show that A. calcoaceticus M10 and the consortium M10-E10 could be adequate inocula in MTBE and TAME bioremediating technologies. 相似文献
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An experimental research into the aqueous photocatalytic oxidation (PCO) of organic groundwater pollutants, methyl-tert-butyl ether (MTBE), tert-butyl alcohol, phenol, humic substances, 2-ethoxy ethanol and ethylene glycol was undertaken using visible light-sensitive
nitrogen-doped titanium dioxide photocatalysts. Nitrogen-doped titania proved to be an effective photocatalyst for MTBE with
its action comparable to and even surpassing that of Degussa P25. In contrast, with the other substances the photocatalysts
showed negligible activity. This difference was explained by the poor adsorption properties of N-doped catalysts. The predominance
of different PCO mechanisms dependent of the surface properties of N-TiO2 catalysts was elucidated. 相似文献
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在pH值7.2~8.5、温度25℃、DO≥5 mg/L的条件下,用含有甲基叔丁基醚(MTBE)的模拟废水对Methylibium petroleiphilum PM1进行富集培养并在陶粒表面挂膜,进而对其特性、性能等进行了研究。填料表面生物膜MTBE降解的序批实验和电镜照片分析均表明陶粒表面已成功附着PM1高效降解菌形成的生物膜。在挂膜后期,当起始MTBE浓度为100~110 mg/L时,经过24 h,MTBE的去除率达到65%以上并基本稳定,其中挥发占4.6%,生物降解起主导的作用。 相似文献