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Superfund success means its OK to play over polluted water, feds say

Cleanup will continue below planned ball fields

By Erik Robinson
Published: June 20, 2010, 12:00am

Federal environmental regulators are keeping a close eye on plans to develop a new complex of sports fields in Hazel Dell.

However, officials with the U.S. Environmental Protection Agency said last week that they don’t expect the ballfield development to affect a contaminated plume of groundwater deep below the surface. Health risks would be negligible for players and spectators who gather on the future ballfields along 78th Street, they said.

“The plume is 50 to 90 feet below the ground surface,” said Judy Smith, a community outreach coordinator with the EPA in Portland. “The vapors were monitored in the area in the mid-’90s, when the concentrations were at their highest. Vapor intrusion wasn’t a problem then.”

Smith noted that the EPA generally encourages redevelopment of former Superfund sites.

In the case of the Boomsnub/Airco cleanup site, a pump-and-treat system has been humming day and night for almost a decade. The system of 24 extraction wells, with 10,000 feet of underground pipe, send 160 gallons per minute through an automated treatment plant on the former Boomsnub chrome-plating facility in east Hazel Dell.

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The contaminated plume, which once reached nearly a mile west to 30th Street, has receded steadily.

“It’s an amazing groundwater cleanup success story from our perspective,” Smith said. “The size of the plume and the contamination in the groundwater is orders of magnitude less.”

Some neighbors remain concerned about the county’s plan to develop sports fields on the 20-acre site.

“To us, this is an experiment and an accident waiting to happen,” said Naomi Davis, who bought a house near the site with her husband, Jack, in 2007.

The county is planning to collect stormwater from the sports fields and allow it to percolate down through pocket gardens and a large man-made wetland.

Bernie Zavala, an EPA hydrogeologist in Seattle, said the agency is planning to review the county’s design.

Depending on the specific location of where stormwater infiltrates the water table 15 to 30 feet below ground, Zavala said, it could skew the plume of contamination that sits 65 to 80 feet below the surface. The EPA wants to make sure the plume stays positioned in such a way that the 24 extraction wells do their job most efficiently.

“The worst thing is, it would increase the time for remediation,” Zavala said.

The problem dates back to 1987, when the state Department of Ecology discovered chromium in the groundwater near Boomsnub.

In 1994, the EPA closed Boomsnub’s electroplating plant at 7608 N.E. 47th Ave., demolished the building and removed more than 6,000 tons of chromium-laced soil. Along with volatile organic compounds spilled by nearby BOC Gases — now owned by Linde Inc. — the underground plume of pollution had migrated 17 blocks west along 78th Street. The government expected the cleanup would ultimately cost about $31 million over three decades. (The EPA expects to shave $3.5 million by infiltrating treated water back into the ground rather than paying to flush it through the city of Vancouver’s sewer system.)

The pump-and-treat system had cumulatively removed 22,107 pounds of chromium and 2,122 pounds of trichloroethene as of the last official five-year review in 2008.

The same review noted that an unexplained spike in TCE had been discovered in the fall of 2007 by a monitoring well at the northwest corner of the intersection of St. Johns and 78th Street. The level of TCE in the well had spiked from 5.1 parts per billion to 330 ppb in a year.

Subsequent chemical analysis revealed the source was not related to the Boomsnub/BOC plume. Smith said it might have been discharged from an old gas station or industrial site.

Whatever the source, Smith said it will be pumped up and treated with the rest of the Boomsnub plume.

“It’s going to be captured by the system in place,” she said. “The only way you could be exposed to this contamination is by drinking well water from a well in this area. The EPA made sure in 1995 that all the private wells in that area are disconnected.”

Erik Robinson: 360-735-4551, or erik.robinson@columbian.com.

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