Gas additive may be polluting one-third of wells in 31 states

Gas additive may be polluting one-third of wells in 31 states

By LEON DROUIN KEITH Associated Press Writer

LOS ANGELES (March 22, 2000 3:24 p.m. EST http://www.nandotimes.com) - About one-third of drinking water wells in 31 states may be contaminated with the gasoline additive MTBE, says a study released Wednesday. The federal government already is acting to ban use of the chemical.

Researchers with the U.S. Geological Survey and the Oregon Graduate Institute's Department of Environmental Study found about 9,000 of 26,000 wells looked at were within a kilometer of a leaking fuel tank, head researcher John Zogorski said.

But Zogorski said it's likely that not all of the 9,000 wells are contaminated with MTBE, or methyl tertiary butyl ether.

"We like to say a significant but currently unknown number of community water supply wells may be at risk," he said. "The number 9,000 is so large that the number of wells that may be affected may well be worrisome."

The study omitted 19 states, including California and Texas, because they lacked needed information on well sites. The study was posted in the online edition of the journal Environmental Science & Technology.

The Clinton administration announced Monday that it is moving to ban MTBE from gasoline, but it will take at least a decade before the possibly carcinogenic substance no longer poses a threat to the water supply.

The study and more than 50 others on MTBE and related issues will be presented this weekend in San Francisco during the national meeting of the American Chemical Society.

MTBE has been used in gasoline for two decades to limit air pollution.

It is hardly the only carcinogenic pollutant to be found in leaking underground fuel tanks. But other pollutants, like benzene, "tend to absorb more toward soil and degrade much faster," Zogorski said.

Many variables play a role in determining whether MTBE will make it into a well, Zogorski said. Key among them is the rate at which wells are pumped.

"Pumping excessively makes the situation worse," said Zogorski, from the Geological Survey. "It draws down contamination into the well. If the pump rate is low, typically the plume (of MTBE) passes right by."