CHATHAM — While officials say a town-wide study to pinpoint the source of contamination by per- and polyfluoroalkyl substances (PFAS) isn’t feasible, the town is seeking a consultant to look for potential PFAS sources in the vicinity of three drinking water wells that have shown detectable levels of the pollution.
PFAS have been identified at various times in three town wells. Well 4 at Indian Hill showed levels below state standards and has been clean for some time now, but wells 5 and 8 off Training Field Road still intermittently have levels above the state standard. Health and Natural Resources Director Robert Duncanson told the select board that it’s important to keep the degree of contamination in perspective.
“These levels are exceedingly low, and in many cases are pushing the limits of laboratory analysis to be able to detect it,” he said. Still, the town prudently took the Training Field well offline; the Indian Hill well was already offline at the time. It was always clear that the PFAS would need to be removed from wells 5 and 8 before they are fully recommissioned, and the town is now in the process of installing special filters that will do so. But when it came to identifying the source of the pollution, the best approach was less straightforward.
“Determining the source is not an absolute, because no matter what the source is, you still have to treat at the wellhead,” Dunanson said last week. One consultant suggested a broad study to find the source at significant expense; another advised a narrower approach with a much lower cost. “So we felt it was prudent to kind of take a step back, reevaluate where we were with all the testing, see what it was telling us,” and then create a new request for proposals from consultants that was more specific. That new RFP is expected to be issued soon.
Town officials have maintained that it may never be possible to find the source of the PFAS in the groundwater, “in the absence of a smoking gun, if you will, like the Barnstable County Fire Training Academy,” Duncanson said. There, years of using firefighting foam presented an obvious source of the pollution, which is present in much higher concentrations than the ones found in Chatham. Because PFAS are also present in a variety of household products, “the extremely low levels that we are seeing in the Chatham wells -- barely at or below the state [maximum contaminant levels] -- could imply that septic systems may be a source,” he said.
Speaking at a recent health board meeting, Duncanson said the need to keep PFAS out of the water supply may outweigh the need to identify a specific source of the pollution. Resident Gloria Freeman said she is troubled by that approach.
“It is disappointing to me to learn that such a study has not already begun, and worse, that it might not happen,” she told the select board last week. Finding the source is the best way to remediate the problem, Freeman argued. “Otherwise we may be faced with monitoring and mitigation that grow into interminable, expensive treatment,” she said. She questioned whether PFAS may have originated at businesses in Commerce Park, or from the fishermen’s storage area at the airport, which she described as an “open dumping ground.” When it comes to finding the source, given the importance of clean groundwater, “this should not be a money issue,” Freeman said.
Duncanson said there are businesses in Commerce Park and off Enterprise Drive that use hazardous materials, but those businesses are regulated, inspected and monitored. Both areas are believed to be outside the groundwater “capture zones” for wells 5 and 8, he added. Likewise, the groundwater contamination that occurred during the Acme Laundry fire decades ago at Frost Fish Creek would have been too far away, and involved a different group of contaminants, Duncanson said.
The updated RFP asks for consultants willing to study the capture zones for wells 4, 5 and 8, looking at current and historic land uses, with potentially some limited use of test wells. There is no point in testing remote parts of town like Nickerson Neck or Morris Island, which are too far afield to be suspect. “The same thing with the whole Town Forest area” along the Harwich border, Duncanson said. If contamination were coming from that area, one would expect it to have been detected in the public drinking water wells in that area, he said. Those wells continue to test clean.
Because groundwater moves at a predictable rate in a predictable direction, it is possible that the PFAS contamination originated in the area of the airport, despite the fact that it is no longer present in Well 4, the closest well. It is possible that a plume of PFAS passed by Well 4 when it was deactivated and showed up farther away in wells 5 and 8 years later.
“That’s part of what the consultant will be charged with looking at,” Duncanson said. By studying the exact groundwater travel times, “we could potentially narrow down a potential source,” he said.
In issuing a new request for studies, “I think we’re moving in the right direction on this,” select board member Dean Nicastro opined. Board member Jeffrey Dykens agreed, saying he would also like to review PFAS test results from the wells of other Cape towns, for comparison.
“I don’t want us to stray too far away from a source investigation,” board member Cory Metters said. While finding the source and remediating it may be costly, “if we don’t have clean drinking water, that’s when it gets really, really, really expensive,” he said.