Impact of Ethanol on the Natural Attenuation of Benzene, Toluene, and o-Xylene in a Normally Sulfate-Reducing Aquifer

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• 作者：Douglas M. Mackay ; Nicholas R. de Sieyes ; Murray D. Einarson ; Kevin P. Feris ; Alexander A. Pappas ; Isaac A. Wood ; Lisa Jacobson ; Larry G. Justice ; Mark N. Noske ; Kate M. Scow ; John T. Wilson
• 刊名：Environmental Science & Technology
• 出版年：2006
• 出版时间：October 1, 2006
• 年：2006
• 卷：40
• 期：19
• 页码：6123 - 6130
• 全文大小：781K
• 年卷期：v.40,no.19(October 1, 2006)
• ISSN：1520-5851

文摘

Side-by-side experiments were conducted in a sulfate-reducing aquifer at a former fuel station to evaluate theeffect of ethanol on biodegradation of other gasolineconstituents. On one side, for ~9 months we injectedgroundwater amended with 1-3 mg/L benzene, toluene,and o-xylene (BToX). On the other side, we injected thesame, adding ~500 mg/L ethanol. Initially the BToXplumes on both sides ("lanes") extended approximatelythe same distance. Thereafter, the plumes in the "No EthanolLane" retracted significantly, which we hypothesize tobe due to an initial acclimation period followed by improvementin efficiency of biodegradation under sulfate-reducingconditions. In the "With Ethanol Lane", the BToX plumesalso retracted, but more slowly and not as far. The preferentialbiodegradation of ethanol depleted dissolved sulfate,leading to methanogenic/acetogenic conditions. Wehypothesize that BToX in the ethanol-impacted lane werebiodegraded in part within the methanogenic/acetogeniczone and, in part, within sulfate-reducing zones developingalong the plume fringes due to mixing with sulfate-containing groundwater surrounding the plumes due todispersion and/or shifts in flow direction. Overall, this researchconfirms that ethanol may reduce rates of biodegradationof aromatic fuel components in the subsurface, in bothtransient and near steady-state conditions.