POWNAL — PFAS chemicals found in surface and shallow groundwater at a former town landfill were high enough to prompt supplemental testing.
The town discovered two years ago that what is called the West Landfill off Maple Grove Road was inadequately lined and covered when closed in the 1980s. A preliminary assessment found that some of the buried materials had begun to migrate into groundwater and also away from the site — located west of the current Pownal Transfer Station.
The problem manifested itself as a solar energy firm was examining the old landfill in 2018 for possible placement of a solar array. Legacy dumped material was found to be visible at the surface.
Kurt Muller, an environmental engineer with Vanasse Hangen Brustlin Inc., representing the town for the project, updated the Select Board last week.
He said during a meeting that a supplemental phase of what was termed the Phase 2 site assessment will further examine groundwater, including in some bedrock private water wells in the area; sample a pond on the opposite side of Maple Grove Road, and try to determine how far the PFAS chemicals have migrated into a forested area to the west of the site.
The town's long-range goal is to produce and have accepted by state environmental officials a corrective action plan to mitigate or contain the PFAS — per- and polyfluoroalkyl substances — and deal with any other contamination issues or hazardous materials at the site.
Muller said soil samples taken "came back clean" for the most part, but PFAS was found in some water samples at relatively high levels.
The plan for additional testing, he said, includes adding some monitoring wells around the site and some mini-wells in the forested area to further evaluate the PFAS contamination. Private wells in roughly a quarter mile area around the site also will be tested, he said.
With soil contamination not considered "a big deal" at this point, Muller said that ideally, the mediation would involve continued monitoring of the area and capping the site with an impervious barrier. If there is contamination in the deep water wells, that could require filtering at the individual properties.
PFAS includes PFOA (perfluorooctanoic acid) and other of related man-made chemicals, some of which were used in water-resistant coatings in industry. Others were used in firefighting foam.
In Pownal, the former Warren Wire/General Cable Co. factory off Route 346 used Teflon that contained PFOA, which in turn was later found in elevated levels in the Fire District 2 well about 1,000 feet from the factory building. That contamination is being filtered at the well site.
PFAS also were detected and in other sites in North Pownal and Pownal Center where suspected dumping of materials or industrial activity occurred. In those cases, PFAS chemicals also were detected in some private wells.
Focus on groundwater
Shawn Donovan, with the state Department of Environmental Conservation's Brownfields Response Program, said Monday that there will be a focus in the next testing work on the groundwater and include "an initial round of drinking water samples."
He said about a dozen private wells in the general area are being considered for testing, adding that there will also be an emphasis the directional flow of groundwater under the landfill.
Donovan said information from deep bedrock private wells will be useful in determining the extent of the contamination emanating from the old landfill and if the contamination extends into the deeper groundwater.
If levels above the state minimums for PFAS chemicals are detected in private wells, filtering systems on site and/or other mitigation, sealing or collection and treatment measures around the landfill could be considered.
Donovan said that from the record of solid waste dumping at the West Landfill site, industrial sources were suspected for the PFAS chemicals. In addition, he said, materials that were exposed at the surface included wire and other items associated with manufacturing.
Because of their nature as water repellents, PFOA and other materials are not expected to break down in the near future, and some believe they will remain in affected groundwater for many decades or longer.
Among strategies for dealing with such contamination around state and nationally have been carbon filtering at drinking water sources, which can remove PFAS; collecting water leaching from a contaminated site for treatment at a wastewater facility; and sealing the contamination within a landfill or other hazardous waste site.
Pownal has obtained a loan for the remediation project from the DEC's Clean Water State Revolving Fund, which includes zero interest loans and subsidies.
The town previously obtained an estimate for the entire remediation project, including the assessment work, of $750,000. But Donovan said the exact cost won't known until a formal corrective action plan is prepared and approved.
Jim Therrien writes for New England Newspapers in Southern Vermont, including the Bennington Banner, Brattleboro Reformer and Manchester Journal. Twitter: @BB_therrien