Methyl tert-butyl ether (MTBE) is the most commonly used gasoline oxygenate in the North American's fuel industry.Due to its high solubility in water and low sorption tendency in soils,MTBE has become one of the most common contaminants in urban ground water.This paper examined the potential for phytoremediation of MTBE within a carefully designed bioreactor.Pre-rooted willow trees (Salix alba) were kept in an Erlenmeyer flask of 500 mL with 450 mL spiked aqueous solution for 12 d.MTBE and the main metabolite TBA were measured by GC/FID.Willow tree uptake tests indicated that the removal of MTBE mass in aqueous solution through willow tree activities was found in the range of 24.84~53.27% at 15·~25·over a 12-day period of exposure.The fraction of MTBE (%) removed from the aqueous solution by willow trees was positively correlated to tree transpiration (mg).Neither TBA,nor any other possible metabolite of MTBE was tracked in this test,indicating phytovolatilization is the dominant mechanism for phytoremediation of MTBE.Results of the bench-scale studies indicated that a large fraction of MTBE was released into the air without any conversion through willow trees over a short period of time,however MTBE will be susceptible to photooxidation and does not become an air quality concern.Therefore,it is to conclude that phytoremediation is an effective method to clean the soil and groundwater contaminated with MTBE.
[1] Steffan R J, McClay K, Vainberg S, et al. 1997.Biodegradation of the gasoline oxygenates Methyl tert-butyl ether, ethyl tert-butyl ether, and tert-amyl methyl ether by propane-oxidizing bacteria [J]. Applied Environmental Microbiology, 63:4216-4222.
[2] Zhang Q L, Davis C, Erickson L E. 1999. An experimental study of phytoremediation of MTBE in ground water.Proceedings of the 1999 Conference on Hazardous Waste Research [A]. Manhattan:Kansas State University, 227-242.
[3] Fayolle F, Vandecasteele J P, Monot F. 2001. Microbial degradation and fate in the environment of MTBE and related fuel oxygenates [J]. Applied Microbial Biotechnology,56:339-349.
[4] Garrett P, Morean M, Lowry J D. 1986. MTBE as a groundwater contaminant. Proceedings of MWWA/API Conference on Petroleum Hydrocarbons and Organic Chemicals in Groundwater-Prevention, Detection, and Restoration [M]. Houston, Texas, Nov. 12-14, Dublin, Ohio,National Water Well Association. 227-238.
[5] Borden R C, Daniel R A, LeBrun L E, et al. 1997. Intrincis biodegradtion rates of MTBE and BTEX in a gasoline-contaminated aquifer [J]. Water Resources Research, 33(5):1105-1115.
[6] Cowan R M, Park L. 1996. Biodegradation of the gasoline osygenates MTBE, ETBE, TAME, TBA, and TAA by aerobic mixed cultures [A]. Buffalo, NY:in 28th Mid-Atlantic Conference. 523-530.
[7] Mormile M R, Liu S, Suflita J M. 1994. Anaerobic biodegradation of gasoline oxygenate:extrapolation of information to multiple sites and redox conditions. [J]Environmental Science and Technology, 28(9):1727-1732.
[8] Salanitro J P, Diaz L A, Williams M P, et al. 1994. lsolation of a bacterial culture that degrades Methyl tert-butyl ether (MTBE) [J]. Applied and Environmental Microbiology,60(7):2593-2596.
[9] Yeh C K, Novak J T. 1994. Anaerobic biodegradation of gasoline oxygenates in soils [J]. Water Environmental Research, 66:744-752.
[10] Church C D, Tratnyek P G, Pankow J F, et al. 1999 Effects of environmental conditions on MTBE degradation in model column aquifers [M]. U. S. Geological Survey, Water Resources Investigation Reports 99-4018C. Portland:Organ Graduate Institute, 3:93-101.
[11] Schnoor J L, Licht L A, McCutcheon S C, et al. 1995.Phytoremediation of organic and nutrient contaminants [J].Environmental Science and Technology, 29(7):318-323.
[12] Newman L A, Gordon M P, Heilman P, et al. 1999.Phytoremediation of MTBE at a California naval site [J]. Soil and Groundwater Cleanup Feb./Mar. 42-45.
[13] Hong M S, Farmayan W F, Dortch IJ, et al. 2001.Phytoremediation off MTBE from a groundwater plume [J].Environmental Science and Technology, 35:1231-1239.
[14] Rubin E, Ramaswami A. 2001. The potential for phytoremediation of MTBE [J]. Water Research 35(5):1348-1353.
[15] Trapp S, Yu X Z, Mosb k H. 2003. Persistence of MTBE against metabolism by Danish vegetation [J]. Environmental Science and Pollution Research (Accepted).
[16] Trapp S, Zambrano K C, Kusk K O, et al. 2000.phytotoxicity test using transpiration of willows [J]. Arch.Envir. Contam. Toxicology, 39(2):154-160.
[17] Hong J Y, Wang Y Y, Bondoc F Y, et al. 1999. Metabolism of MTBE and other gasoline ethers by human liver microsomes and heterologously expressed human cytochromes P450:identification of CYP2A6 as a major catalyst [J]. Toxicol. Appl. Pharmacol., 160:44-48.
[18] Komossa D, Langebartels C, Sandermann J H. 1995.Metabolic processes for organic chemicals in plants. Plant contamination-modeling and simulation of organic chemical processes [M]. USA:Lewis, Boca Raton, F1.
[19] Frick C M, Farrell R E, Germida J J. 1999.Assessment of phytoremediation as an In-situ technique for cleaning oil-contaminated sites [M].Saskatoon:University of Saskatchewan Deparment of Soil Science, SK Canada.
