A screenshot of an online map shows samples taken in the wake of a firefighting foam spill showcase various sample sites near Brunswick Executive Airport. A majority of the sample sites shown on this portion of the map were domestic water wells. The DEP will be sampling wells again in the coming week. Courtesy of the Department of Environmental Protection

The Maine Department of Environmental Protection will resume testing this week for toxic “forever chemicals,” as part of an effort to determine whether a disastrous firefighting foam spill at the Brunswick Executive Airport on Aug. 19 contaminated nearby private drinking water wells.

Officials will go back to take samples at private homes along Coombs Road and other nearby roads in Brunswick on Wednesday and Thursday to test for per- and polyfluoroalkyl substances, or PFAS. This round of testing comes months after the first sample batch in September showed concerning levels of PFAS in many wells, though these results are unlikely a result of the spill, given the slow rate of ground water movement.

“The area selected for testing by DEP has been evaluated as the most likely residential area to show impacts from the August 19th AFFF spill, should they occur,” said DEP Deputy Commissioner David Madore in an email to The Times Record. “The Navy, in conjunction with [Environmental Protection Agency] and DEP, had identified the possibility for contamination to migrate into this target area and had previously conducted residential water supply sampling in 2016 and again in 2022.”

The sampling from September and this month are just two of the several planned tests in the wake of Maine’s worst toxic chemical spill in 30 years, in which 1,450 gallons of PFAS-containing aqueous film-forming foam (AFFF) mixed with 50,000 gallons of water were accidently released into the airport’s Hangar 4 and the nearby environment. Madore noted that PFAS were detected in several water supplies during the 2016 and 2022 samplings, and that the results of the September samples were compared with this historical data.

“Results are below Maine’s interim drinking water standard of 20 parts per trillion for the Sum of Six PFAS, meaning that filter treatment systems have not been required to be installed,” Madore said, referring to a drinking water regulation that limits specific PFAS compounds in supplies. “The DEP evaluates multiple lines of evidence, including concentration trends and PFAS compounds detected, to help make decisions about additional actions that are needed to protect public health and the environment.”

The DEP’s test results from September, however, show high levels of some of the PFAS compounds that are more stringently regulated by the EPA. For instance, PFOS — a particularly harmful compound within the PFAS family — is limited to 4 parts per trillion (ppt) in public drinking water by the EPA as of spring 2024, though the agency also set an unenforceable health guideline at zero parts per trillion. DEP results show many wells with some level of PFOS detection, including one well sample showing 9.42 ppt.

While the new EPA guideline is more stringent and aims to prevent PFAS exposures to about 100 million people and prevent thousands of deaths, the regulations placed on public drinking sources are not regulated in private wells. The DEP also currently uses an interim guideline of 20 ppt for exposure in public drinking water until the Maine Drinking Water Program adopts the new EPA rule. Public water suppliers have until 2027 to complete initial monitoring and until 2029 to address PFAS that exceed limits set within the Sum of Six guideline.

To date, the DEP maintains that public drinking water is safe for consumption.

A slew of sampling on the horizon

PFAS can be hard to spot — unless it takes a foam form, as was seen here at the Aug. 19 spill in Brunswick that became Maine’s worst toxic chemical spill in 30 years. Kristian Moravec / The Times Record file photo

Just two days after the spill in August, the DEP downplayed the risk for private drinking wells. At the time, state officials said they planned to ask nearby residents for permission to test their private drinking water wells but would not be sampling every well owner. The department later said that it will be testing wells every three months over the next year.

The DEP began its first round of sampling in the neighborhood near the airport, which was formerly Naval Air Station Brunswick until it closed in 2011 and is now home to hundreds of businesses and residents.

Officials used an EPA-verified testing method known as Method 537.1 modified with isotope dilution for sampling homeowner water supplies. Each water-testing method analyzes for a limited amount of PFAS that are concerning to human health. The agency is using the more stringent EPA Method 1633 — which tests for more PFAS compounds than the 537.1 method — for soil, surface water and other non-drinking water material. 

The chemical family of PFAS, also known as forever chemicals, can be harmful to human health and cause ailments such as decreased fertility, developmental delays, cancer and more, according to the the EPA. The agency also states that exposure to PFAS can happen in many ways, including by drinking contaminated water.

“We are finding in various private wells, low concentrations — and I say ‘low,’ and that’s relative to Maine DEP’s 20 part per trillion standard, although some of the numbers we’re seeing are above EPA’s 4 parts per trillion number, so they are still of concern,” said State Environmental Scientist Iver McLeod. “But at those levels, and especially when you are below 4, (we) are thinking these days is related to faulty septic systems.”

McLeod also noted that there could be other potential sources causing PFAS detection other than septic issues and the toxic foam spill. For instance, PFAS detection could also possibly be a result of constructing a new home, as a homeowner may have spread loam sourced from an area with PFAS onto their property. PFAS are also found in many common consumer products, such as makeup, fabric and more.

Madore told The Times Record in November that the agency had received several requests for well sampling in Brunswick outside of the targeted spill sampling area. He said that these wells were determined by staff evaluation to not be at risk from the AFFF discharge. He said that this assessment was based, in part, on how far the wells were located from the spill and on knowledge of the area hydrology. 

He noted recently, however, that the DEP will still consider reimbursement requests for PFAS testing up to a certain amount. The reimbursement comes with restrictions — sampling must be done in accordance with the DEP’s sampling guidelines, residents must use a Maine-accredited and DEP-approved laboratory, the property owner has to provide the laboratory results to the DEP, the data must be determined to be of good quality, and the source of PFAS detected has to be tied to the recent AFFF release.

Any resident can still have well water tested with EPA-certified labs, but they will have to pay out of pocket, and sampling at these labs can cost hundreds of dollars.

Data from the next round of testing are expected to be available late January. More information about well testing can be found at maine.gov.