Another 37 wells in Bennington have tested positive for the carcinogen perfluorooctanoic acid, state officials said Tuesday.
The Department of Environmental Conservation tested the wells after monitoring wells near the Bennington Landfill revealed the chemical in groundwater at concentrations exceeding the state limit of 20 parts per trillion.
Residents south of the Bennington Landfill who use private drinking wells are being asked, if they have not done so already, to sign up to have their wells tested.
More than 100 Bennington wells had already been discovered to contain perfluorooctanoic acid, also known as PFOA, at levels over 20 parts per trillion.
“It expands the area of concern that much more,” said Danika Frisbie, public information coordinator for the state’s PFOA response. “It just proves that this is going to be a long-term project.”
The chemical, both a component once used to manufacture Teflon and a toxicant emitted by Teflon under high heat, is thought to have originated from the former Chemfab factory in Bennington, which manufactured Teflon-coated fiberglass.
Of 40 wells tested near the landfill, 34 showed PFOA concentrations over the state’s 20 parts per trillion limit, Frisbie said. Another three revealed the chemical in concentrations below 20 parts per trillion.
At least two ponds in the North Bennington area, along with the Walloomsac River, also contain PFOA in sediment, according to test results released last month, but state officials say it’s not a risk to human health.
The state recently tested 63 private wells in Pownal, after a municipal water supply serving around 450 people was found to carry PFOA in concentrations exceeding the state’s recommended limit. Only four of those 63 came back with PFOA concentrations above 20 parts per trillion. The highest concentration was 66 parts per trillion.
Samples from eight out of 10 streams and ponds in the Bennington area also recently came back positive for PFOA, as have wells serving over 100 households near North Bennington.
The pollution is thought to have originated from three factories formerly owned by the same Vermont entrepreneur, John Ransom Cook. Cook started Warren Wire in Pownal and Chemfab in Bennington, which he later moved to North Bennington.
Officials have not yet determined by what precise route the chemical left the factories and found its way into Vermonters’ drinking water and surface waters. But at other PFOA-contaminated sites in the United States, the chemical was introduced into the environment through smokestacks, according to documents released in a lawsuit Dupont over PFOA pollution in West Virginia.
PFOA is believed to cause cancer and disrupt endocrine systems, affecting the liver, kidneys, testes and bladder. It is also thought to cause hypertension and high cholesterol.
Blood testing is available for residents whose water was contaminated, as is clean drinking water.
