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09/30/2003 07:00:00

Caltech Researchers to Receive Award for Environmental Contribution

PASADENA, Calif. – With the presentation of the prestigious Jack Edward McKee Medal to Hui-Ming Hung, Joon-Wun Kang, and Michael R. Hoffmann, the Water Environment Federation (WEF) is recognizing the environmental importance of the three scientists' work.

The McKee Medal, named for the past WEF president and Caltech professor, was created to honor achievement in groundwater protection, restoration, and sustainable use. The medal is awarded for significant contributions to the field of groundwater science or engineering, published in any WEF journal.

The three scientists are being honored for their article, "The Sonolytic Destruction of Methyl tert-butyl Ether Present in Contaminated Groundwater," which was published in the December 2002 issue of Water Environment Research.

Hoffmann is the James Irvine Professor of Environmental Science and the dean of graduate studies at Caltech. Hung received her PhD under Hoffmann's tutelage and is currently a postdoctoral researcher at Harvard University. Kang spent a year as a visiting associate in Hoffmann's laboratory and is currently a professor in the department of industrial environment and health, Yonsei University, Korea.

Since 1990, methyl tert-butyl ether (MTBE) has been added to gasoline to meet the oxygenate requirements established by Congress in the Clean Air Act Amendments. Oxygenates are a family of chemicals that increase the oxygen content of gasoline, thereby allowing cleaner and more complete consumption of the fuel. MTBE, because it is less expensive and easier to transport than other oxygenates, has been extensively used by refiners and is found in close to 90 percent of treated gasoline. MTBE-treated gasoline has helped to improve air quality, reducing smog-forming pollutants by at least 105,000 tons and toxins by at least 24, 000 tons annually.

However, the benefits of MTBE come at a price. Leaks from storage containers and spills during transportation have led to a growing problem of MTBE contaminating groundwater, including drinking-water sources. The potential health risks of MTBE have not yet been determined, but the offensive odor and taste of the chemical can make water undrinkable. Because MTBE is not as biodegradable as other gasoline components, it has become a persistent problem that traditional methods of decontamination have proved unsuccessful in treating.

In their paper, Hung, Kang, and Hoffmann applied the established technique of ultrasonic irradiation to the removal of MTBE from a crude sample of contaminated groundwater. They first analyzed the mechanism of ultrasonic degradation in pure water spiked with MTBE, and then compared the degradation in the spiked sample to that in water collected beneath JFK International Airport, New York. They demonstrated that the destruction of the MTBE in the crude sample occurred efficiently, thus establishing the usefulness of ultrasonic irradiation for decontamination. Their thorough characterization of this technique has laid the groundwork for the development of a practical system for the efficacious removal of MTBE from contaminated groundwater.

WEF will recognize the three scientists on October 14 during WEFTEC.03, the largest water-quality conference and exhibition in North America. This year marks the 76th annual meeting which will be held from October 11 to 15 at the Los Angeles Convention Center. ###

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