EPA officials studied the effectiveness of cleanup efforts at the Superfund site on the Bennington-Woodford border last year. The land was formerly used as a landfill, salvage yard and sand pit by the Burgess Brothers Construction Co. from the 1940s to the mid-1970s.
The study, the second such study to be conducted on the site since the 1998 plan was implemented, found that contamination had spread beyond the boundaries of the 3-acre dump site. The agency thought its original cleanup plan, which included a cap over the site and a soil vapor extraction system, which would prevent migration of contaminants beyond the landfill’s borders.
A similar 2005 review showed that rainwater and snow melt were prevented by the cap from seeping into the contaminated area. But that study also showed that contaminants had spread somewhat from the site.
EPA signed a Record of Decision in 1998 calling for the cap and the soil vapor extraction system to address groundwater contamination. Contaminants, including trichloroethene (TCE) and tetrachlorothene (PCE), were found in groundwater at depths up to 30 feet. The plan was expected to reduce the water to near-drinking levels in about seven years.
“The expectation was we’d put in this remedy and within seven years we’d be done. The groundwater would be cleaned up and the source material would be removed from this landfill,” said Terrence Connelly, a project manager with EPA.
Groundwater in the bedrock more than 150 feet beneath the site was and remains unaffected, according to EPA officials.
Connelly said contamination levels actually rose for some time and spread beyond the site, however. They are now beginning to diminish but additional remediation efforts are needed to prevent further migration from the dump site, he said.
According to Connelly, two new trenches will be constructed that will be about 200 feet in length and up to 25 feet deep. The trenches, known as “barriers,” will be filled with zero-valent iron, which are essentially iron shavings, and sand, Connelly said. The iron will break down the contaminants as groundwater flows through it.
“It does not release iron into the water so we’re not exchanging chemicals for iron,” Connelly told about a dozen people at a public hearing Tuesday.
The cost of the new remediation efforts is estimated at about $4 million. Actually costs could be as much as $6 million or as low as about $3 million, according to Connelly.
The original cost estimate to mitigate the contamination at the site was $3.6 million, according to Connelly. The EPA and potentially responsible parties, including Burgess Brothers Construction Co., Clyde Burgess Jr. and Eveready Battery Co., signed a consent decree in 1999 to cover the costs.
That consent decree must be re-negotiated because the cleanup plan is changing, Connelly said. Burgess Brothers was purchased in June by Rutland-based Earth Waste Systems, however.
It is possible that the responsible parties could be different this time, Connelly said. “That will have to be for the attorneys and the Department of Justice to look at that,” he said. “They will have to decide who to send the notices to say, ‘OK, we want to re-negotiate.'”
Connelly said there are provisions in the laws and rules that deal with contaminated properties changing ownership. However, it is unclear if Earth Waste Systems will be considered a potentially responsible party.
“It’s not an automatic that they would be a party in negotiations, but it’s not a given either that they would be excluded,” Connelly said.
Officials at Earth Waste Systems did not respond Wednesday to a request for comment.
The dumping that took place at the landfill was done legally, according to Connelly. No criminal activity is alleged to have taken place.
According to a timeline presented Tuesday, EPA officials expect it will take about one year to negotiate with potentially responsible parties. The new trenches would not be constructed until 2014.
The length of time the process must remain in place is not known, Connelly said. “We don’t know how much source material remains beneath the landfill,” he said.
A stream on the property is a tributary to Barney Brook, which ultimately joins with the Wallomsac River. Connelly said contaminants are have not been detected “well before (the stream) gets to Barney Brook and well before Barney Brook gets to the river.”
Contact Neal P. Goswami at firstname.lastname@example.org