PFAS Detected In Private Well In Shawkemo Above Imminent Hazard Threshold

Another private well on Nantucket has tested above the state’s imminent hazard threshold for PFAS, in an area of the island where high concentrations of the so-called “forever chemicals” had not previously been detected.

The well, located on Fulling Mill Road in Shawkemo, tested at 106 parts per trillion (ppt) of PFAS, over the imminent hazard threshold of 90 ppt and more than five times higher than the 20 ppt the Massachusetts Department of Environmental Protection has set as the public drinking water standard, also called the Massachusetts Maximum Contaminant Level (MMCL).

“This is in a somewhat new place,” town environmental contamination coordinator Andrew Shapero said. “Previously, we haven't seen detects over the state standard particularly close to this.”

The well is near the edge of the buffer zone of known PFAS contamination established by a single test over the MMCL in Polpis, but not close to any of the detections that have crossed the imminent hazard threshold. It’s the latest evidence that Nantucket’s PFAS problem is widespread and remains poorly understood.

“We should by no means consider the extent of PFAS contamination on the island to be delineated,” Shapero said at a previous meeting. “We should expect that we're going to get more detects, unfortunately, and so we really need to be getting the word out.”

As with several recent hotspots, the source of the contamination is unknown.

In addition to the imminent hazard detection, there have been six more detections above the MMCL since the last update the Board of Health received, and 22 detections below the MMCL. One of those detections, on Long Pond Drive, also led to the slight expansion of a PFAS buffer zone.

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.

There are thousands of PFAS, but MassDEP only tests for six, known as PFAS6, meaning that actual PFAS concentrations could be higher than what the official testing shows.

Learn more about private well testing on Nantucket by clicking here.