BENNINGTON — After a second round of water testing for PFAS substances at five Vermont schools, only one result — at Grafton Elementary — remained above the state's 20 parts per trillion standard for drinking water.
"Obviously, we would have liked to have none," said Emily Boedecker, commissioner of the Department of Environmental Conservation.
But it was encouraging, she said, that the pilot program involving 10 schools found only one instance of a PFAS (per- and polyfluoroalkyl substances) level above the state standard among schools with wells selected because they were considered the most at risk of contamination.
The re-testing confirmed that seven of the original 10 schools tested did not have any detectable PFAS, while two others had levels below 20 parts per trillion. Five schools were found to have no detectable amounts in the first round and were not re-tested.
The Grafton Elementary water supply showed 22 parts per trillion in both tests.
Boedecker said the DEC is considering what type of filtering system or other response would be best to provide clean drinking water to the Grafton school. The DEC also will further investigate the source, degree and extent of the contamination of the school's water supply.
After the first round of testing in July, bottled water was offered to the schools with detectable amounts of PFAS.
Boedecker said the principal change in PFAS levels between the first and second testing rounds indicated that one of the five related compounds the state measures — PFHpA (perfluoroheptanoic acid) — was accidentally introduced during the sampling process or in the laboratory, and therefore might not be present in the water source.
PFHpA was found in some of the initial test results, but it was not detected in any of the samples in the retesting. That change served to drop the PFAS total for Warren Elementary School in Warren from 36.6 ppt. to 10.1 ppt.
Warren also had PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonic acid) in both tests, totaling 10.1 ppt. in the second round.
Grafton had 11 ppt. of PFOA and 11 ppt. of PFOS in each test, for a level of 22 ppt.
Eden Central School in Eden had 4.9 ppt. of PFOA in the first round and 5.3 ppt. of the substance in the second.
Lamoille Union USD 18 in Hyde Park had 12 ppt. of PFHpA initially and was non-detect for PFAS in the second round.
And Smilie Memorial School in Bolton dropped from 3.8 ppt. of PFHpA to non-detect in the second test.
Monitoring of the schools that had detectable levels in the first tests is continuing to ensure PFAS results remain consistent with the current findings.
Initial testing at five other Vermont schools did not detect any PFAS substances.
Bryan Redmond, director of the Drinking Water and Groundwater Protection Division, said DEC personnel met this week with Grafton school officials to discuss filtering options for the water system, with the goal of completing the installation prior to the start of classes in the fall.
There currently is a "do not drink" order in place, he said, and bottled water is being supplied.
After the on-site filtering unit is operating, Redmond said, another test will be required to ensure it is removing the contaminants.
Boedecker said the DEC will continue to work with the affected schools to keep staff, parents and students safe and informed. The DEC also is investigating to determine the sources of any contamination and how to those situations might be remediated.
And the state continues to evaluate whether there's a need to conduct additional testing at other schools. The 10 schools tested during the week of July 9 were selected from among 129 schools with an on-site water supply that were considered possibly vulnerable to PFAS contamination, said Chuck Schwer, director of the DEC's Waste Management and Prevention Division of the, following the initial testing.
The pilot program was undertaken in cooperation with the state Department of Health and the Agency of Education and is part of DEC's statewide strategy for addressing PFAS contamination. That testing began in 2016 after discovery of widespread PFOA contamination around two former ChemFab Corp. factories in Bennington, and subsequent discovery of PFAS sites in other Vermont communities.
Also in early July, the DEC and Department of Health announced that the state would begin testing for a total of five PFAS substances in drinking water and considering any combination of levels above 20 ppt. as not meeting the Vermont standard.
The new compounds added to PFOA and PFOS (a substance found in firefighting foam) were three additional PFAS substances, perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), and PFHpA.
Boedecker said testing for PFAS often must be repeated because the measurements present many challenges, including the fact of dealing with parts per trillion amounts that are difficult to pinpoint at low levels, along with a recent demand placed upon a limited number of qualified laboratories as state's around the nation are reacting to the environmental threats posed by PFAS contamination.
Additionally, Boedecker said there is a lack of information concerning what products, such as floor cleaners or waxes that might be considered a PFAS source in schools, contain the substances. Vermont has been in the forefront of the efforts to deal with PFAS because of the contamination in Bennington, but Boedecker said she hopes the federal Environmental Protection Agency, which is seeking input around the county on these issues, and other federal agencies will provide more testing and reliable information about PFAS.
There are more than 4,000 known related PFAS substances, used today or in the past in commercial or industrial products or in the manufacture of products, such as Teflon.