ABSTRACT
Methyl tert-butyl ether (MTBE) and related oxygenates are commonly added to gasoline in the United States to reduce ozone formation and carbon monoxide emissions and to increase the octane level in fuel. MTBE is the most common fuel oxygenate because of it’s low cost, ease of production, high octane, lower evaporative emissions, and favorable transfer and blending characteristics. Several different research groups have identified mixed and pure cultures of microorganisms with the ability to degrade MTBE under aerobic conditions. The field data from the Sampson County site suggest that there may be some MTBE biodegradation near the original underground storage tank release. In this area, the presence of other fuel hydrocarbons may have stimulated the growth of MTBE degrading organisms. However further downgradient, there was no evidence of MTBE degradation. Toluene, ethylbenzene, and m-,p-xylene are rapidly biodegraded; whereas, o-xylene, benzene, and MTBE are more slowly biode-graded.
