Cutting air pollution at the cost of water quality?
SAN FRANCISCO, March 27 -- The 1990 Clean Air Act amendments dramatically increased the use of oxygenates to make cleaner-burning gasoline. The most widely used oxygenate is MTBE (methyl tertiary butyl ether), followed by ethanol. Air pollution from older vehicles has declined, as intended, but MTBE is turning up in drinking and surface water supplies. Recent coverage has cited limited information on MTBE's impact on drinking water. Now, more than 50 research papers on MTBE and related issues will be presented during the 219th national meeting of the American Chemical Society, the world's largest scientific society, in San Francisco, Calif., March 26-30. Topics include the extent of MTBE contamination, risks to human health, the government's response, bioremediation and other cleanup methods, and alternatives to MTBE. Selected studies are described below.
- Health risk issues for oxygenates: Much is known about the consequences of inhaling MTBE, far less
about ingesting it. Most studies of ethanol have focused on its use and abuse as an intoxicant, not
its use as a fuel additive. Information on other oxygenates is even spottier. (J. M. Davis, National
Center for Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park,
N.C.; ENVR 63; Monday, March 27, 4:30 p.m., Hilton Imperial B, Ballroom Level. See page 106 in the
final program.)
- Will the potential substitutes for MTBE create longer or shorter plumes? MTBE contaminates water more
readily than other gasoline constituents, even benzene. This paper examines alternatives to MTBE and
whether they are likely to be better or worse in this regard. (B. Hartman, Transglobal Environmental
Geochemistry, Solana Beach, Calif.; ENVR 79; Tuesday, March 28, 9:50 a.m., Hilton Imperial B, Ballroom
Level. See page 106 in the final program.)
- Effects of environmental conditions on MTBE degradation in model column aquifers: The researchers
tracked the rate at which MTBE degrades in sediments from four sites with different geological
features. They found that on its own, MTBE degrades neither rapidly nor readily. (C. D. Church, Oregon
Graduate Institute, Portland, Ore.; ENVR 120; Wednesday, March 29, 10:40 a.m., Hilton Imperial B,
Ballroom Level. See page 107 in the final program.)
- Field tests of enhanced intrinsic remediation of an MTBE plume: Solely by adding oxygen to sediment samples -- in lab and in field tests -- the researchers succeeded in inducing bacteria native to Vandenberg Air Force Base to rapidly digest and destroy MTBE. (D. Mackay, University of Waterloo, Ontario, Canada; ENVR 230; Thursday, March 30, 9:50 a.m., Hilton Imperial B, Ballroom Level. See page 108 in the final program.)
A nonprofit organization with a membership of 161,000 chemists and chemical engineers, the American Chemical Society www.acs.org publishes scientific journals and databases, convenes major research conferences, and provides educational, science policy and career programs in chemistry. Its main offices are in Washington, D.C., and Columbus, Ohio.