The plan to use hemp to solve Maine’s “perennial chemical problem” is hitting a major hurdle

LIMESTONE, Maine – An Aroostook County tribe has found that industrial hemp plants are extracting so-called forever chemicals from contaminated soil on land it owns at the former Loring Air Force Base.

There’s a problem: Nobody knows what to do with the hemp.

“There was no way to remove the PFAS from the plants without putting them back into the environment,” said Richard Silliboy, deputy chief of the Mi’kmaq Nation.

Finding a way to remove per- and polyfluorinated alkyl substances, known as PFAS, from contaminated hemp plants without inadvertently releasing them into the air is the next step in the tribe’s efforts to clean up 650 acres of polluted land owned by the U.S -Government passed 15 years ago.

Using hemp plants to absorb PFAS from the soil is being touted across the country as a possible solution to widespread pollution. But the Maine tribe’s experience has shown there is a significant barrier to making it work. There will soon be tests to find a solution to the hurdle.

PFAS refers to a group of manufactured chemicals commonly found in household and personal care products that have contaminated soil and water at former manufacturing sites. The long-lasting “forever chemicals” are known to break down slowly and have been linked to an increased risk of some cancers, hormonal and immune system problems, developmental delays in children and other health problems, according to the Environmental Protection Agency .

The land that the federal government donated to the Mi’kmaq Nation in 2009 was so contaminated that it was designated a federal Superfund site. The Mi’kmaq site was once a key training area for Loring firefighters, who used PFAS-laden foam.

The Air Force promised the tribe it would remove all known toxins before the land transfer in 2009, but that didn’t happen, Silliboy said. The Mi’kmaq are largely on their own to remove PFAS from their land.

Michael Daly, EPA cleanup project manager for Loring Air Force Base, said some of the Mi’kmaq land is part of an Air Force study to determine how far foam may have traveled from Loring Airport. Daly directed further questions about the cleanup to the Air Force.

Air Force spokespeople did not respond to requests for comment.

Instead of waiting for federal investigators, tribal leaders found their own way to begin removing PFAS from the soil on their properties.

In 2019, Silliboy and Chelli Stanley co-founded Upland Grassroots, an organization dedicated to cleaning up Mi’kmaq allotments. Stanley, who lives near Hallowell and has experience in community organizing, learned about hemp-based PFAS extraction and contacted Silliboy, who was immediately interested in the potential.

This year, Stanley, Silliboy and other tribal members planted and harvested several small plots of hemp plants on the Loring property. They sent the harvested hemp to the Connecticut Agricultural Experiment Station, a state scientific research facility.

Initial data showed that the hemp plants extracted various forms of PFAS, including perfluorooctane sulfonic acid, or PFOS. In the summer of 2022, the group planted five larger plots, with four hemp varieties grown in smaller sections within each plot.

Of the 28 types of PFAS identified in soil, 10 were found in the harvested hemp plants, according to a study the group published earlier this year.

Stanley and the Mi’kmaq Nation eventually want to expand the number and size of hemp plants to test larger-scale PFAS extractions. But without a safe way to dispose of the PFAS-laden hemp, the group’s research can only be conducted on a smaller scale.

“We don’t want to send the hemp to a landfill and make it someone else’s problem,” Stanley said.

One of the group’s scientific partners, the University of Virginia, is currently developing a method to remove PFAS from hemp plants and will test it soon, said Bryan Berger, a chemical engineering professor.

Berger wouldn’t reveal which method will be tested, but said that if successful, he and his colleagues could publish the results in early 2025.

Hemp, like other plant species that contain toxic pollutants, cannot simply be burned, said Berger.

“This ultimately creates airborne forms (of PFAS) that can enter the atmosphere,” Berger said.

Hemp-based research related to PFAS extraction has been limited because industrial hemp was only approved for agricultural use in 2018 and funding for such studies remains limited. But Berger and tribal partners recently found an important source of funding to expand their efforts and work toward long-term solutions.

Starting in 2025, the Mi’kmaq Nation, Stanley, Berger, the Connecticut Agricultural Experiment Station and the Central Aroostook Soil and Water Conservation District will use a four-year, $1.6 million EPA grant to continue growing hemp in Loring and possible ways to extract PFAS from harvested hemp.

As part of the grant, the group will also test areas of the Aroostook River, a waterway that the Central Aroostook Soil & Water Conservation District has determined contains PFAS due to irrigation runoff from nearby crop fields. They will study hemp as a potential rotation crop to prevent PFAS from seeping into potatoes and other produce.

The agricultural studies are a continuation of work the conservation district has already begun, Berger said. His lab will test about 300 to 400 water samples from the Aroostook River, as well as potatoes and other crops, to determine the extent of PFAS contamination.

With colleagues from the Connecticut station, the group will study how PFAS moves through insect food chains using sample insects from Aroostook.

Berger credited the initial collaboration between the Mi’kmaq Nation and Stanley as one of the first groups to study PFAS and hemp at the community level and raise awareness of their potential.

“As a researcher, I haven’t seen many people working on this until recently, so they’re way ahead of everyone else,” Berger said. “Our goal is really to help other tribes, farmers and rural communities impacted (by PFAS).”