PFAS Contamination At Public Water Well Prompts Town To Seek Treatment System

One of the seven wells that provide Nantucket's public water supply has been contaminated by a creeping, underground plume of the forever chemicals known as PFAS that has already shut down private wells on Toms Way, the small dirt road located across the street from the Wannacomet Water Company's Wyer's Valley pumping stations.

The contaminated well, which taps groundwater from the shallow level of Nantucket's sole source aquifer, has been shut down since late 2022 as PFAS testing revealed a rising concentration of the chemical. In response, Nantucket Water Department director Mark Willett said he is now pursuing a multi-million dollar emergency treatment system that he hopes to have installed at Wyer's Valley by the summer. Willett is also closely monitoring the island's six other public water wells - two of which are in close proximity to the one that was shut down due to PFAS contamination - and pursuing the permitting of a new deep well at North Pasture, where the town's new water tower is located off Polpis Road. The Water Department is now sampling all of the public water wells on a monthly basis.

"As we sampled it, we could see the PFAS numbers getting a little bit bigger," Willett told the Current this week, referring to what is known as Well 15 at Wyer's Valley. "It started out always good, non-detected, like all our other wells. And then we got a little tiny hit of one or two (parts per trillion or PPT), and then six months later, it's at 8 (PPT). And then it got into the teens. When we got into the teens, I turned it off. I'm not going to take a chance. This is now the backup well. We'll run (well) 16, and that can take care of it. And I thought if we ever needed it, it's still under the limit. We're at the point now where it's above the limit. I can't turn it on. If did turn it on, I'd be polluting the whole system."

Willett said that with Well 15 shut down, the town's drinking water is and has been free of PFAS, and his department has been able to meet the town's water demand with the remaining six wells, three of which are located at Wyer's Valley, one at North Pasture, and two in 'Sconset. Testing on the other six public water wells shows that PFAS has not been detected. But the shutdown of Well 15 has impacted water pressure for island residents at points of high demand during the summer, and he is concerned that if there was a major fire like the one that struck the Veranda House in July 2022, the existing pumping stations would not be adequate without turning on Well 15.

Used to manufacture stain- and water-resistant products, the family of chemicals known as PFAS is suspected to increase the risk of kidney and testicular cancers, as well as other health conditions. They are often called "forever chemicals" because they do not break down and remain present in the environment. The chemicals are used in a wide range of products from non-stick pans, to fast food wrappers, to firefighting foam.

In Massachusetts, the Department of Environmental Protection has set the public drinking water standard, also called the Massachusetts Maximum Contaminant Level (MMCL), at 20 nanograms per liter (ng/L), or parts per trillion (PPT). The federal Environmental Protection Agency proposed a national drinking water standard for some types of PFAS as low as 4 PPT.

“Our entire island relies on one precious, sole-source aquifer," said Ayesha Khan, a co-founder of the Nantucket PFAS Action Group. "The situation with Well 15 highlights its fragility and our responsibility to protect it. Nantucket has always been a place where people work together to protect what matters. By reducing PFAS use, advocating for regulations that treat PFAS as a family of chemicals, and supporting PFAS-free alternatives, we can show how collective action at the local level can drive meaningful change”

The source of the PFAS contamination at Toms Way, where "staggering" levels of PFAS were discovered in residents' private drinking wells in September 2023, is still unknown. The island residents who were impacted filed a class action lawsuit against the manufacturers and suppliers of PFAS, and the town paid to connect the affected properties to the municipal water supply. Meanwhile, the Massachusetts Department of Environmental Protection launched an investigation of the nearby Fairgrounds Road municipal campus (the site of the former Nantucket Electric Company) as a potential source contributing to high levels of PFAS on Toms Way. The state agency began drilling 12 monitoring wells late last year, and during Thursday's Board of Health meeting, the town's special projects manager Chuck Larson shared groundwater testing results from samples taken in December. Nine of the 12 wells showed hits for PFAS6, with levels between 4.9 and 22.3 PPT.

"The concentrations, the highest is just over 20 PPT, which is the groundwater limit for PFAS6 (in Massachusetts), and that's just behind the police station," Larson said. "The results for the other wells are less than that. Three locations were non-detect. There's not really a pattern to the results, other than what we see toward the center of the parking lot...There is nothing to indicate this seems to be coming from this area toward Toms Way. This is preliminary information, just 12 data points and Mass DEP will be making more comments."

"It's pretty horrifying to me that only three of them were non-detect," Board of Health member Meri Lepore said. "I don't think that's a win. The federal government is saying four or lower (PPT). That's terrible. It's awful. I think we have a real problem."

When the Toms Way PFAS contamination was first detected, with some properties showing levels over 100 PPT, it was immediately alarming for Willett given the proximity to the town's public drinking water wells at Wyer's Valley.

"That's a par four away from Well 15," Willett said. "That's like 400 yards."

The natural direction of the groundwater flow in the area, he said, goes from Toms Way through Wyer's Valley and toward Nantucket Harbor.

Two of Nantucket's public water wells at Wyer's Valley (Wells 15 and 16) pump groundwater from a shallow aquifer at about 75 feet, while the remaining three wells (Wells 12, 13, 14) pump groundwater from a deeper aquifer at about 150 feet beneath a semi-confining layer of soil that separates the two.

Willett is concerned that utilizing the shallow wells (15 and 16) could pull the PFAS plume closer toward Wyer's Valley. While Well 16 has not yet had a hit for PFAS, Willett said, he's kept it shut off during the winter because it is not needed to meet demand, and out of concern about pulling the plume closer.

Meanwhile, Willett and the Nantucket Water Department are in the process of commissioning a new public water well at North Pasture, which would tap the deeper level of the aquifer. He anticipates it could be online within a year, depending upon the speed of the state Department of Environmental Protection's permitting process.