Signature Metabolites Attesting to the In Situ Attenuation of Alkylbenzenes in Anaerobic Environments

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• 作者：Mostafa S. Elshahed ; Lisa M. Gieg ; Michael J. McInerney ; and Joseph M. Suflita
• 刊名：Environmental Science & Technology
• 出版年：2001
• 出版时间：February 15, 2001
• 年：2001
• 卷：35
• 期：4
• 页码：682 - 689
• 全文大小：96K
• 年卷期：v.35,no.4(February 15, 2001)
• ISSN：1520-5851

文摘

Accurate assessment of the fate of hydrocarbons spilt inaquifers is essential for gauging associated health andecological risks. Regulatory pressure to actively remediatesuch contaminated ecosystems can be substantiallydiminished if solid evidence for in situ microbial destructionof pollutants is obtained. In laboratory incubations, sediment-associated microorganisms from a gas condensate-contaminated aquifer anaerobically biodegraded toluene,ethylbenzene, xylene, and toluic acid isomers withstoichiometric amounts of sulfate consumed or methaneproduced. The activation of the alkylated aromaticcontaminants involved conversion to their correspondingbenzylsuccinic acid derivatives, a reaction known to occurfor toluene and m-xylene decay, but one previouslyunrecognized for ethylbenzene, o- and p-xylene, andm-toluate metabolism. Benzylsuccinates were furtherbiodegraded to toluates, phthalates, and benzoate. Inlaboratory incubations, these metabolites were transientlyproduced. Several of the metabolites were also detectedin groundwater samples from an aquifer where alkylbenzeneconcentrations decreased over time, suggesting thatanaerobic microbial metabolism of these contaminantsalso occurs in situ. Our studies confirm the utility of theaforementioned compounds as signature metabolites attestingto the natural attenuation of aromatic hydrocarbons inanaerobic environments.