BENNINGTON — Two of 10 Vermont schools tested for PFAS chemicals in well water supplies had levels above the state's advisory level of 20 parts per trillion.
Water tests at three other schools in the pilot testing program showed levels below the state standard, while at five others, no PFAS (per- and polyfluoroalkyl substances) was detected.
According to Kimberly Caldwell, an environmental analyst with the state Department of Environmental Conservation, the on-site water supply at Warren Elementary School in Warren, Washington County, had a PFAS level of 36.6 parts per trillion, and Grafton Elementary School in Grafton, Windham County, had a level of 22 ppt.
In early July, the Vermont Department of Health and state environmental officials announced the pilot testing program in part to determine whether additional school water supplies should be tested as well. The DEC said there are 129 schools in Vermont with well water sources that might be considered vulnerable to PFAS contamination.
Also this month, the health department announced that tests of drinking water will now include results for three additional PFAS substances, perfluorohexane sulfonic acid (PFHxS), perfluoroheptanoic acid (PFHpA) and perfluorononanoic acid (PFNA).
That is in addition to tests for PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonic acid), which have been conducted since in early 2016, when PFOA contamination was discovered around two former ChemFab Corp. factories in Bennington.
Revised PFAS standard
Going forward, state officials said, the total level in water of all five PFAS substances would be counted in determining whether the contamination exceeded the 20 ppt standard.
Caldwell said that at Warren Elementary, PFHpA was detected at 24 ppt, PFOA at 8.1 ppt and PFOS at 4.5 ppt, for a total of 36.6 ppt.
At Grafton Elementary, PFOA was detected at 11 ppt and PFOS at 11 ppt, for a total of 22 ppt.
Other schools where PFAS was detected, but at below 20 ppt levels, included Eden Central School in Eden, 4.9 ppt of PFOA; Smile Memorial Elementary in Bolton, PFHpA at 3.8 ppt; and Lamoille Union USD 18 in Hyde Park, PFHpA at 12 ppt.
She said all of the schools where the contamination was detected have been notified and bottled water was offered to those with levels over the state standard.
All of those water supplies also have been retested, and results from federal Environmental Protection Agency laboratories is expected in about two weeks.
Caldwell said the state is still verifying the results of the first tests and will consider whether the testing program should be expanded to other Vermont schools.
Water also was tested at Sharon Elementary School, Charleston Elementary, Marlboro Elementary, Ripton Elementary and Charleston Elementary but PFAS was not detected. The samples were taken the week of July 9.
PFAS refers to a large group of compounds used in a variety of industrial processes and found in numerous consumer products.
Those include in floor cleaners and waxes, nonstick surfaces on cooking utensils and pans and in tape products.
The PFOA that contaminated more than 300 wells in the Bennington area is believed by the state to have emanated from exhaust stacks at the former ChemFab factories, which coated fiberglass and other fabrics with Teflon. PFOA was used in the manufacture of Teflon.
Medical studies relating to PFOA found that exposure to the compound through drinking water was associated with high cholesterol, ulcerative colitis, thyroid disease, testicular cancer, kidney cancer and pregnancy-induced hypertension.