THETFORD — Under a state law passed in May 2019, Vermont environment officials started testing public water supplies around the state for PFAS, a class of chemicals that can infiltrate groundwater and can cause health issues.
PFAS, which is short for per- and polyfluoroalkyl substances, came to public attention around industrial sites, particularly in Bennington, Vt., and Merrimack, N.H., which host factories owned by Saint-Gobain, a multinational corporation that uses PFAS. But the chemicals are used in so many products that they are all around us, in food packaging and household products, carpets and nonstick cookware.
Even so, when testing revealed levels of the chemical in the drinking water at Thetford Academy in December 2019, it came as a surprise. Of 587 public drinking water systems tested by state in 2019, five returned levels of PFAS above the state-set maximum contaminant level, or MCL, of 20 parts per trillion, said Dana Nagy, the Drinking Water Community Operations Section supervisor at the Vermont Agency of Natural Resources.
The state has worked with 12 water systems on remediation and conducts quarterly monitoring of another 19, Nagy said.
“It has so many different uses and has been in so many products, it’s hard to know where it’s come from,” Nagy said of PFAS in a phone interview.
The test required Thetford Academy, which relies on its own well on Thetford Hill, to address the contamination, work that was completed last year with the installation of a carbon filter. Testing in October returned no sign of PFAS in the grade-7 to -12 school’s drinking water, state officials said.
The issue in Thetford pointed to how widespread PFAS are and to how the state is engaged in a long effort to monitor water quality. Other sites where the state found elevated PFAS levels were in the ski towns of Killington, Fayston and Stowe, VtDigger reported.
“This is ongoing,” Nagy said of the state testing and remediation. “This isn’t anything that’s going to resolve itself quickly.”
The Centers for Disease Control and Prevention’s website says the health effects from exposure to low environmental levels of PFAS are “uncertain.” But tests of laboratory animals given large amounts of the chemical have found that some types may “may affect growth and development, reproduction, thyroid function, the immune system, and injure the liver,” according to the CDC.
Among the issues the state has encountered, which have included water supplies at everything from condominium associations to day care centers, Thetford Academy’s was resolved quickly. A test above 20 parts per trillion results in an immediate “do not drink” order.
“Fortunately, we had the entire holiday break to locate bottled water resources and have safe drinking water in place when faculty and staff returned to campus at the start of the new year” in January 2020, John Brown, Thetford Academy’s director of buildings and grounds, wrote Tuesday in response to emailed questions. “We did ask faculty, staff and students to bring drinking water from home in reusable containers to help defray the cost of bottled water and reduce paper cup waste.”
The school hired Otter Creek Engineering to help determine what the school’s options were. The source of the contamination wasn’t readily apparent, so it wasn’t clear that drilling a new well would solve the problem, and the Thetford Hill Water Coop, which was untouched by the contamination, didn’t have supply sufficient to meet the school’s demands, Brown wrote.
Thetford Academy had tested for 56 parts per trillion and 55 parts per trillion in two separate tests, levels that fall above the state’s MCL, but are still very low. “With the low PFAS numbers, filtration was the most viable solution,” Brown wrote.
Nagy said Thetford Academy paid $43,650 for the carbon filtration system, and that the state will reimburse the school 75% of that sum from a fund set up by the Legislature. The school also is eligible for full reimbursement of $4,100 worth of bottled water, Nagy said. The school is working with the state on reimbursement.
With the water safe to drink, the school will move ahead and conduct any further monitoring the state requires, Brown said.
The central mystery, where the PFAS came from, remains unsolved. Thetford Academy had to submit a site investigation report to the state, which it sent in last week.
“In this report, there is no clear evidence of any one source of contamination or if it is limited to the Thetford Academy campus,” Brown said. Floor cleaning and waxing products the school used contained PFAS ingredients, and field marking paint and perhaps even cross-country ski wax might have contained PFAS.
The investigation will continue, Nagy said, though it’s unclear what form that will take. What is clear is that the state will continue to test for PFAS. It’s not going to just disappear.
“The way they talk about this, they say it’s a forever chemical,” Nagy said.
Alex Hanson can be reached at ahanson@vnews.com or 603-727-3207.