Small-Volume Releases of Gasoline in the Vadose Zone: Impact of the Additives MTBE and Ethanol on Groundwater Quality
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- 作者：Nathalie Dakhel ; Gabriele Pasteris ; David Werner ; and Patrick Hö ; hener
- 刊名：Environmental Science & Technology
- 出版年：2003
- 出版时间：May 15, 2003
- 年：2003
- 卷：37
- 期：10
- 页码：2127 - 2133
- 全文大小：161K
- 年卷期：v.37,no.10(May 15, 2003)
- ISSN：1520-5851
文摘
A controlled gasoline spill experiment was performedunder outdoor conditions typical for winter in temperateregions to study the fate of methyl tert-butyl ether (MTBE),ethanol, benzene, and selected other petroleum hydrocarbons. Artificial gasoline containing MTBE and ethanol(5% w/w of each) was placed at a defined depth into a 2.3m thick unsaturated zone of alluvial sand overlying agravel aquifer in a lysimeter. During an initial period of 41days without recharge, MTBE and hydrocarbon vaporsmigrated by vapor-phase diffusion to groundwater, whileethanol vapors were naturally attenuated. In a subsequentperiod of 30 days with 5-mm daily recharge, all solublecompounds including ethanol were transported to thegroundwater. Ethanol disappeared concomitantly withbenzene and all other petroleum hydrocarbons exceptisooctane from the aerobic groundwater due to biodegradation. MTBE persisted for longer than 6 months atconcentrations larger than 125 000 
g L-1. No evidencefor MTBE biodegradation was found, whereas >99.6% ofethanol removal from the lysimeter was due to biodegradation.It is concluded that MTBE-free gasoline would be lessharmful for groundwater resources and that ethanol is anacceptable substitute.
g L-1. No evidencefor MTBE biodegradation was found, whereas >99.6% ofethanol removal from the lysimeter was due to biodegradation.It is concluded that MTBE-free gasoline would be lessharmful for groundwater resources and that ethanol is anacceptable substitute.