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EPA proposes clean up plan for Williston Superfund site

By Stephanie Choate
Observer staff

The Environmental Protection Agency has released its proposal to clean up contaminated groundwater in Williston, after years of studying the site.
A plume containing high levels of compounds used to clean metals, including trichloroethylene and tetrachloroethylene, has contaminated groundwater beneath Commerce Street, South Brownell Road and Kirby Lane.
“The groundwater is extremely contaminated,” said EPA Remedial Project Manager Karen Lumino. “It’s a 70-acre plume.”
Buildings and homes in the area use municipal water rather than wells, however, so there is no current health risk, according to the EPA.
The area became a federal Superfund site in 2005. Quebec-based Mitec Telecom (now Mitec Technologies) has been named as the source of at least some of the contamination and has paid a $120,000 settlement, “based on its ability to pay.”
The EPA began studying the site in 2008. Since then, it has collected groundwater, surface water, soil, sediment and vapor samples.
The EPA has wrapped up its feasibility study at the site and is proposing a three-pronged approach to dealing with the contamination.
First, it would utilize an institutional control—possibly a town ordinance—to ensure that no one is allowed to use the groundwater in the area.
Second, it would treat the groundwater—in situ, or underground, rather than pumping it above ground to be treated—in the more contaminated sections under Commerce Street. Those treatments include chemical oxidization—injecting reagents like hydrogen peroxide or ozone into the ground.
“These reagents break down the chemicals underground,” Lumino said.
The chemicals would likely be injected in the EPA’s existing groundwater monitoring wells.
In less contaminated parts of the plume, the EPA would use in situ bio remediation, the third step. This involves introducing naturally existing microbes that eat the contaminants.
While the site is not currently a health risk, Lumino said Vermont’s goal is for all groundwater to be potable.
“We could just let (the contamination) sit there and let Mother Nature take care of it, but that would take 1-200 years, based on our modeling,” she said. “With active treatment, we’re hoping to cut cleanup time down to decades.”
Lumino said the EPA estimates that the cleanup plan as proposed would cost $8.4 million.
The EPA is also proposing to remove some contaminated soil near the former site of the Mitec plant, left over from the state’s cleanup of the site.
The EPA’s recommendations are still proposals at this point. The EPA will post its studies and recommendations online by Aug. 5, available at www.epa.gov/region1/superfund/sites/commercestreet. All documents related to the site will be available at the Dorothy Alling Memorial Library by Aug. 5.
At a public information meeting set for Aug. 12 at 7 p.m. at the Town Hall, EPA and Vermont Department of Environmental Conservation officials will lay out the cleanup proposal. They will collect comments at a public hearing, set for 8 p.m.
A public comment period begins Aug. 6 and runs through Sept. 4.
Once the comment period is over, EPA officials will evaluate the comments to see if any information collected changes their recommendations. Lumino hopes to issue a final record of decision by the end of September. Then, it’s a waiting game. Because the site is a federally managed Superfund site, it has to wait for its allotment of federal tax dollars. Lumino said that could take a year, or much longer.
“We have to get in line,” she said.
For more information, contact Karen Lumino at 617-918-1348 or lumino.karen@epa.gov