MTBE
January 25, 2000
On Sunday January 16, 2000 CBS’s “60 Minutes” aired a report on MTBE, the acronym for Methyl tertiary butyl ether. The gasoline additive, intended to clean up automobile air emissions, is now a problem to the nation’s drinking water, according to the story line. Steve Kroff, “60 Minutes” newsperson presented a sobering story on the growing problem of MTBE contaminating the nation's drinking water supply. It was described as “The biggest environmental crisis of the next decade." First found in the ground water supply of Santa Monica, California four years ago, 70 percent of the City's wells were contaminated with the pollutant, requiring the purchase of water from an outside source. It’s reported that Santa Monica has spent $15 million to fix the contamination problem and has only scratched the surface. According to the telecast, the contaminant has now been found in 10,000 wells in California. Likewise, MTBE has been found in a number of major cities across the United States, affecting about 20 percent of the nation’s urban wells. It contaminates the groundwater drinking supply through leaking gasoline storage tanks. This was the case in Santa Monica, and all of the other examples used in the “60 Minutes” telecast.
MTBE has been used since 1979 and is the most common oxygenated additive used by the petroleum industry. First used as an octane booster, it later was used to meet the requirements of federal legislation. The Oxygenated Fuel Program was implemented by USEPA in 1992 in response to requirements of the 1990 Clean Air Act passed by Congress and signed by President Bush. MTBE was the oxygenated additive of choice because of its low cost, ease of production and blending characteristics. Four and one-half billion gallons of MTBE is produced every year. The use of oxygenates in gasoline is required only in those areas of the United States that have air quality problems.
According to a paper appearing in the January American Water Works Associations Journal, ”MTBE is a concern to the drinking water supply profession because of its strong taste and odor effects, potential risk to human health, tendency to migrate rapidly in groundwater, and resistance to conventional water treatment processes." As to the effects to human heath, little is known about the health risks. Bob Perciasepe, EPA Assistant Water Administrator, admitted in the telecast that there has been no health effects testing and that more needs to be done in this regard. It is estimated that 100 million people are exposed to water that may be tainted with MTBE.
Salt Lake City has done some limited testing for MTBE. Four wells located along the east bench were tested in 1996 and no MTBE was detected. In 1999, Salt Lake City participated in an American Water Works Research Foundation (AWWARF) project, entitled "National Assessment of MTBE Occurrence in Drinking Water." Water was sampled and tested from Big Cottonwood Creek with no detection of MTBE.
Oxygenated additives have not been required in gasoline sold in Salt Lake County. Therefore, the chances of this contaminate polluting Salt Lake City's wells is unlikely. The testing so far confirms this. It is apparent that national testing requirements will be promulgated in the near future. With testing and regulations, more will be known about this new environmental threat. In the mean time EPA has issued a drinking water health advisory of 20 to 40 micrograms per liter MTBE.
Questions regarding this article can be directed to: florence.reynolds@ci.slc.ut.us