CHEMICAL FREE: A federal soil cleanup and new treatment system have made the water drinkable.
By John Dodge
The Olympian, 3/2/99
TUMWATER - Three Tumwater city wells tainted with an industrial chemical since at least 1993 are back in .service this week, thanks to a costly treatment plant built by the federal government.
Tests now show that the treated water entering the city's water supply is free of trichloroethylene, a toxic chemical that, at high doses, has been linked to liver, kidney and central nervous system damage.
The three wells were taken off-line by the city when the chemicals were discovered during routine sampling in August 1993.
Federal officials have since determined that the sources of the pollution, which is decades old, were two state Department of Transportation sites, a Trosper Road gas station and a Capitol Boulevard dry cleaner.
The site was placed on the federal Superfund list in April 1997.
The well pollution has served as a telling reminder that South Sound drinking water supplies, which rely solely on groundwater, are vulnerable to chemical leaks, spills and improper disposal.
Losing the well production pinched the city's water supply, especially in the summer, when people water their lawns and usage doubles. The city has only about a dozen wells, and the closed wells could produce about 1,000 gallons per minute - or about a quarter of the summer supply.
The presence of low levels of TCE in the city wells raised health concerns among some city residents. However, state health officials have said, the low concentrations found less than the federal drinking water standard of 5 parts per billion - and the short exposure time of no more than three years all but rule out possible health effects.
An unknown amount of trichloroethylene remains in the groundwater flowing toward the Palermo wellfield in Tumwater Valley. Another solvent called tetrachloroethylene also is moving through the groundwater but hasn't reached the wells.
But U.S. Environmental Protection Agency officials said there is a good chance the $2 million treatment system now in place will keep removing the solvents from the water for years to come, EPA on-scene coordinator Thor Cutler said.
If the chemical is measured in the treated water - even in concentrations allowed by drinking water regulators - the city probably wouldn't use it, said Kathy Callison, Tumwater water resources program manager.
"The city is proud of our water quality," Callison said. "Our goal is to keep the chemical at a nondetectable level."
Here's how the treatment system works: Groundwater is pumped to the top of 39-foot treatment towers. As the water cascades and tumbles through a maze of plastic, filtered air is blown from the base of the towers.
The contaminates evaporate and are released into the air the clean water is sent to the city water system.
Cutler said the airborne solvents, which will amount to about 10 pounds a year at the current rate, quickly break down. The air pollution is roughly 50 times lower than air quality standards for the chemical.
About 45 families live between Capitol Boulevard and Tumwater Valley Golf Course in what's called the Palermo neighborhood. That's where the solvents were detected.
"The water is sure a lot safer than it was before they built the treatment plant," said neighbor Dennis Koeppen. "In a way, we are all guinea pigs, but I'm not going to worry about it."
Donna Henderson, another resident, is suspicious of all the glowing project reports from city and federal officials. -
"If it's to improve the water, I guess it's OK," she said. "But I don't think we're getting the whole story. We don't know what the long-term ramifications will be from the pollution."
John Dodge covers the environment for The Olympian. He can be reached at 754-5444.
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