WELLFLEET — Drinking water in the well serving a private home on Chequessett Neck Road contained nearly seven times the state’s limit for PFAS when it was tested in the spring. State and local health authorities are still working to find the source of contamination.
The test was part of a state program offered to residents of towns where at least 60 percent of the homes have private wells.
The results for Wellfleet, which came out in late May, showed the Chequessett Neck Road residential well, located between Holbrook Avenue and Hamblen Farm Road, had tested at 139 parts per trillion (ppt). Massachusetts has set a limit of 20 ppt for the sum of six PFAS (per- and polyfluoroalkyl substances) in drinking water.
Health authorities did not disclose the address of the house with the high test result. The homeowner was notified, as were other residents nearby.
Edmund Coletta, director of public affairs for the state Dept. of Environmental Protection (DEP), said 139 parts per trillion is considered an “imminent hazard” level, which means it poses a potential health risk.
“MassDEP took steps to eliminate the exposure to the resident by installing a point-of-entry treatment system,” Coletta said in an email. The state agency has been working with the Wellfleet health agent since then and is currently making attempts to sample all residential private wells within 500 feet of the house with the imminent hazard condition, Coletta said.
So far, some of those nearby wells have also shown evidence of PFAS, and a few exceeded the 20 ppt limit.
MassDEP is also evaluating potential PFAS sources in the town, Coletta said. But he added that “no definitive sources have been determined yet.”
Hillary Greenberg-Lemos, Wellfleet’s health and conservation agent, said well sampling continues in the Chequessett Neck Road area. “We just want to rule out any more widespread contamination,” she said.
Greenberg-Lemos said she has contacted the town fire dept. to see if in the past there were fires near the affected location that might have been extinguished with a firefighting foam that contains PFAS. She did not say whether there has been a response from fire officials or when she expects one.
Massachusetts is one of just a handful of states that have set a strict limit for PFAS, which are known as “forever chemicals” because they never completely degrade. Dating back to the 1950s, they have been used in nonstick cookware, grease-resistant food packaging, outdoor clothing, stain-resistant carpeting, and other everyday consumer goods.
Health studies indicate that sufficiently elevated levels of PFAS can have harmful effects on fetuses and infants and on the functioning of the thyroid, liver, kidneys, and immune system. They can cause elevated cholesterol. The National Cancer Institute has studies underway following up on earlier incomplete findings linking PFAS to various cancers.
Property owners in both Wellfleet and Truro were given the opportunity to sign up for the PFAS testing program that was offered in 84 communities statewide. In Wellfleet, 45 homeowners had the tests done on their wells. Of those, three were above the 20 ppt limit. They included one at 35 ppt, one at 62 ppt, and the one that tested at 139 ppt, according to the DEP’s website, where test results are published.
Another 10 residential wells had some PFAS but in concentrations below the 20 ppt limit.
In Truro, 33 homeowners had their private wells tested. Three samples showed the presence of PFAS but none exceeded the state limit, according to the DEP’s posted findings.
Sleuthing the Sources
In an unrelated study done in 2021, 101 private wells in 12 towns across Cape Cod were tested for PFAS as part of a collaboration among the University of Rhode Island, Harvard’s T.H. Chan School of Public Health, and the Silent Spring Institute. While nearly half showed the presence of at least one PFAS chemical, most of the wells did not exceed the state limit.
One conclusion drawn from study results was that wells with higher levels of nitrate had higher PFAS concentrations on average, suggesting that septic systems could be a source of PFAS in private wells.
Laurel Schaider, a senior scientist at Silent Spring Institute, said in a phone interview Monday that the connection between nitrates and PFAS levels makes sense. “PFAS is widely used in households, so it’s not surprising it would end up in the wastewater,” she said. “But that’s just one way, and it doesn’t prove it’s the main source.”
Regarding the sample that tested at 139 ppt in Wellfleet, Schaider said, “It’s probably unlikely to be from septic system discharge,” given the high concentration.
And while the town has a closed, unlined landfill on Coles Neck Road, Schaider said it would also be unlikely to find such high PFAS levels in leachate from that source. A private well would not have the strong draw on groundwater that a municipal well would and likely would pull from a smaller area, said Schaider. Groundwater direction will also be a factor in finding the source of the contamination.
Schaider agreed with Greenberg-Lemos’s hunch the contamination could be due to use of PFAS-containing agents used in an emergency response to a fire.
Meanwhile, during routine testing required of public water supplies, two wells at a condominium complex in Truro were recently found to have PFAS levels edging past the 20 ppt limit. Trustees at Stone’s Throw condominiums are working with MassDEP on solutions.
A Military Connection
Military bases across the country, including Joint Base Cape Cod on the Upper Cape, have been a major source of PFAS contamination in soil and groundwater. Andrew Marks, operations manager for the Mashpee Water District, said one town well was taken offline in the past due to a level of 72 ppt but is now back in operation following the installation of a carbon filter that was paid for by the Air Force. Two other wells in the area of Turner Road in Mashpee are currently offline due to PFAS levels of 23 and 35 ppt, Marks said. A filter house, where the water from both wells will be treated, is nearly completed, also at Air Force expense.
In Falmouth, the U.S. Air Force paid for the installation of a filter system to treat PFAS found in the town’s Fresh Pond well, which just recently returned to service. Hyannis was found to be another PFAS hotspot due to the presence of the firefighter training academy. And in Yarmouth, three of the town’s wells are currently offline because of high PFAS test results.