Martha’s Vineyard Airport Tests Underground Filtration for PFAS Contamination

When officials at Martha’s Vineyard Airport (MVY) became aware that groundwater in and around the airfield may have been contaminated with toxic chemicals from firefighting foam, they took action—even though federal or state regulations did not require it. In 2017, MVY launched a proactive campaign to understand the issue, begin remediation and communicate openly about the matter with its neighbors on the 95-square-mile island haven off the Massachusetts coast.

The airport initially provided bottled water and installed point-of-entry treatment systems at impacted private wells. Its subsequent efforts include an innovative and ongoing $272,500 pilot project that injected a slurry carbon substance into the ground. The liquid-activated carbon creates an in-ground filter that allows groundwater to flow through, but traps and holds toxic chemicals the water might contain. The process is an alternative to traditional methods of pumping and treating tainted water. So far, the results have been notably promising.

The chemicals in question, per- and polyfluoralkyl substances (PFAS), are found in a firefighting product called aqueous film-forming foam (AFFF) used during FAA-required training exercises and to extinguish actual fuel fires at airports and other places. An agency of the Centers for Disease Control indicates that being exposed to PFAS may lead to adverse health effects, including some serious cancers. Drinking water contaminated with PFAS is one of several ways people are exposed. The chemicals have also been used for decades in cookware, carpets, fabrics and other common consumer products.

The U.S. Environmental Protection Agency is in the process of finalizing rules for the production and use of PFAS. A number of states reportedly have moved legislation to varying degrees to ban the substance. Those states include Arkansas, California, Colorado, Connecticut, Illinois, Louisiana, Michigan, Minnesota, Nevada, New Hampshire, Vermont, West Virginia and Wisconsin.

Unfolding Issue

Airports across the United States and abroad have discovered PFAS in their groundwater, and it’s also being detected in communities without airports. “It’s coming from various sources,” says MVY Airport Director Geoff Freeman. “It’s in our daily lives.”

A 2022 National Fire Protection Association report indicates that foam manufacturers have offered alternative products, such as so-called fluorine-free foams (F3), for years, with manufacturers, the military and firefighting entities continuing to research effectiveness, compatibility with equipment, and the best ways to use alternative products on fires.

The PFAS issue emerged at MVY In 2017. Once the possibility of PFAS contamination was clear, the airport hired Tetra Tech, an environmental consultant that has worked with the airport on other projects over the years. Tetra Tech began by testing the groundwater beneath and near the airfield, including water from nearby residential wells. The firm did, in fact, find elevated levels of PFAS. State environmental guidelines recommend, but do not legislate, a maximum of 70 parts per trillion. Some spots at and around MVY tested at more than 1,000 parts per trillion.

That was more than enough for MVY decision makers. They sent a letter to local residents that reported the findings and detailed the airport’s plans to develop a strategy for dealing with the situation.

“MVY made a conscious decision to test for this emerging hazard ahead of regulatory agencies’ potential implementation of new regulations,” Freeman points out. “We’re part of the community of Martha’s Vineyard, and that comes first. We needed to understand how and where these chemicals have impacted our community, and to make the necessary changes to our procedures, and to notify and treat the water supply of the residents affected.”

Innovative Response

Once the chemicals were detected, MVY initiated extensive research that included mapping the site’s geology, charting the flow and depth of groundwater, and monitoring PFAS levels. Armed with that data, the airport commissioned Tetra Tech to implement a pilot program in 2022. During the pilot, personnel placed and tested PlumeStop, a patented in situ remediation technology from Regenesis.

Maureen Dooley, vice president for the company’s industrial sector, compares PlumeStop to a household water filter, noting that the filtering process occurs below ground. Crews inject colloidal-activated carbon into the subsurface, where it coats sand, gravel and rock materials. Groundwater can pass through the underground filter that forms, but pollutants like PFAS are retained on the carbon surface. “It is a ‘barrier’ for contaminants but does not impede water flow,” Dooley explains.

Ron Myrick, a Tetra Tech vice president, says that there are notable advantages to the approach, especially compared to conventional pump-and-treat methods that incur ongoing operation and maintenance costs and require off-site waste disposal. Over time, Myrick estimates that the PlumeStop method can deliver significant savings—“likely several-hundred thousand dollars, as well as reduced liability since no wastes are being disposed off-site where they could be the source of a new problem elsewhere.”

The multi-pronged initiative at MYV included soil assessment, design and approval, installing the carbon barrier and then monitoring its performance. Because it is a pilot project, the barrier does not encompass the entire site in question. Instead, the project team selected a small, key portion: the AFFF testing area located south of Runway 6-24 (the longer of the airport’s two asphalt runways) and west of its wastewater treatment plant. In other words, the carbon barrier went into the ground within yards of where firefighters had discharged AFFF for years during required training exercises, and also downstream from where initial mapping revealed groundwater flows. Installation occurred from November to December 2022.

The groundwater remediation method MVY and its team chose has been used at hundreds of sites worldwide since it was introduced in 2014. Among them are seven other airports and several Department of Defense facilities, including Fairbanks International Airport (FAI), Grayling Army Airfield and two airports in the United Kingdom.

Dooley, who was part of the on-site team at MVY, reports that there were no significant surprises at the small Massachusetts airport. “The treatment zone was relatively shallow—less than 40 feet deep—and predominantly sandy, allowing the injections to proceed smoothly,” she explains. Even so, working at Martha’s Vineyard in late fall and early winter presented challenges, notably “extra coordination and communication to mobilize and demobilize the materials, equipment and personnel to the island, and performing the application during a cold, wet week in December,” says Dooley.

Despite the added challenges, initial results seem encouraging. Myrick reports that regulated PFAS in the immediate area of the new carbon barrier were quickly reduced to less than detectable levels. At a location 25 feet downgradient of the barrier, regulated PFAS were reduced by approximately 80% after about three months (by mid-March 2023). “And the reduction percentage is expected to increase over time as treated groundwater continues to migrate beyond the barrier to downgradient areas,” adds Myrick.

Moving Forward

Naturally, there will be continued quarterly monitoring of the groundwater in 2023 with annual or more frequent monitoring expected thereafter. Beyond that, the precise path forward is pending given that federal and Massachusetts regulations governing PFAS standards, testing, treatment and remediation are still evolving. Airport officials have not determined whether a full-scale carbon barrier project will occur at MVY, nor has a timetable been set for such a decision.

Myrick reports that Tetra Tech is currently performing a study that will include further review of expanded use of PlumeStop and other remedial technologies for implementation. Results are expected this November.

Beyond the science and logistics, MVY must also consider cost implications.

As Freeman points out, the federal government is not providing assistance to airports to help with the situation. “This money is coming out of our operating budget,” he notes. That can be daunting for smaller, seasonal airports such as MVY. Last year, it logged about 42,200 flight operations served roughly 69,000 passengers. Since 2017, it has spent $300,000 to $400,000 per year for PFAS testing and monitoring alone. 

Additionally, keeping up with recent and impending changes to firefighting procedures and products is no easy matter. “Local fire departments can shift to new, more environmentally friendly firefighting substances more quickly than airports, which are subject to more guidance and regulatory requirements of the FAA,” Freeman explains.

Despite the financial and regulatory obstacles, “We’re committed to dealing with a problem that has originated at the airport,” he emphasizes.

Such complexities are everyday realities for airports large and small. “Even with an airport the size of ours, we’re very much our own microcosm of a town,” says Freeman, “We have our own wastewater facility, our own water department, a business park; so there’s a lot of moving parts. It’s not just airplanes coming in and taking off.”

As a result, airports face a diverse range of challenges—including emergent issues like PFAS remediation—that affect their neighbors.

On that point, Freeman is crystal clear: “We take that responsibility very seriously. We are part of this community.”