Researchers in Aroostook County say early studies have revealed unsafe levels of forever chemicals, commonly known as PFAS, in waterways used for irrigating crops.
So far, the presence of the chemicals has not disrupted or shut down crop production in Maine’s northernmost county, known for its abundant and economically vital potato farming.
More research is planned in 2025 and beyond in an effort to learn about the extent of the contamination and whether it has seeped into produce. Those findings could have a significant impact on farmers in the county and beyond.
Fifty-nine Maine farms in central and southern Maine had confirmed contamination from PFAS at the beginning of 2024, largely due to sludge containing 18 types of PFAS spread on farm fields. Most of those farms remain open today, but some have been sold so the land can be used for PFAS research. In Maine, PFAS has also been found in wild game and private drinking water wells, raising health concerns among residents in many communities.
Per- and polyfluoroalkyl substances are known as “forever chemicals” because they do not readily break down in the environment. The man-made chemicals are commonly found in products like food wrappers, water-resistent clothing, scratch-resistant cookware and cosmetics, and have been linked to health issues like cancer, thyroid disease, liver damage, decreased fertility, hormone suppression and high cholesterol when ingested, according to the Environmental Protection Agency.
After learning the extent of PFAS in Maine, including at Aroostook’s former Loring Air Force Base, the Central Aroostook Soil & Water District began studying four waterways to learn the extent of PFAS contamination and hopefully save County farmers much of the hardship their central and southern counterparts have endured.
“A lot of farmers up here are aware of [PFAS] but are scared to know more because of what’s happened in the state,” water district executive director Randy Martin said. “We aren’t at a point where farms could close but we want to prevent that from happening.”
In summer 2023 and 2024, Martin and colleagues sampled water from Greenlaw Brook in Limestone, Madawaska Stream behind DoDo’s Market in Caribou, Limestone Stream behind the Limestone snowmobile clubhouse and from the Aroostook River near the boat launch in Fort Fairfield.
Test results have mostly been well above the EPA’s cap of 6 parts per trillion for all types of PFAS chemicals in drinking water, Martin said.
In 2023, PFAS concentrations of 86 parts per trillion were detected in samples for Greenlaw Brook, 13.2 ppt in Madawaska Stream; 54.7 ppt in Limestone Stream; and 94.4 in the Aroostook River.
Last summer’s results were 12.5 ppt, Madawaska Stream; 26.8 ppt, Limestone Stream; and 3.6 ppt, Aroostook River. Greenlaw Brook was not tested this year.
PFAS levels decreased this year largely due to drier weather conditions, Martin said. More rainfall during summer 2023 caused spring runoff to last longer than normal, increasing waterflow into the streams and river.
Martin chose those waterways because several flow in and out of the former Loring base and are connected to major sources of crop irrigation for farmers.
Greenlaw Brook begins at Loring and flows into Madawaska Stream. Greenlaw Brook is one of many waterways known to have PFAS chemicals from firefighting foam sprayed during the base’s military era, according to the latest findings from an Air Force investigation.
Both Greenlaw Brook and Madawaska Stream flow into the Aroostook River between Caribou and Fort Fairfield. Though farmers have steered clear of Greenlaw Brook, those in Limestone and nearby towns have relied on the others for crop irrigation, Martin said.
Limestone Stream is not connected to Aroostook River, Greenlaw Brook or Madawaska Lake. But the stream is part of the Air Force’s PFAS investigation and included, along with nearby Durepo Pond, in a warning from the EPA advising people not to eat more than 4 meals per year of brook trout and no smallmouth bass from those waters due to PFAS levels.
But not everyone might be aware of those warnings, which is part of Martin’s motivation to learn and share more about PFAS in Aroostook.
“Every time we sampled [at Limestone Stream], someone was fishing there,” Martin said. “Madawaska Stream is a popular swimming and fishing spot.”
For the past two summers, Martin and colleagues planted potatoes, broccoli, yellow beans, kale and other crops in 50×50-foot plots on the district’s research farm in Presque Isle.
They’ve taken nearly 100 soil, plant leaf and crop tissue samples both before and after irrigating the crops with water from Madawaska and Limestone streams and the Aroostook River.
Irrigating the crops with PFAS-infected water could alert farmers as to whether the water they’ve used for years has seeped deep into plant tissues of the crops they plant, Martin said.
The soil, plant and crop samples are still being analyzed in the district’s lab, located at the University of Maine at Presque Isle. Martin expects to know the full results in early 2025 and start sharing that information with local farmers.
The District’s research will contribute important County-based information to the growing field studies into PFAS on Maine farms, said Jim Britt, director of communications for Maine’s Department of Agriculture, Conservation and Forestry.
The Department’s PFAS Response Program has tested 84 farms in Maine and has found that the uptake of PFAS into crops like potatoes, grains, broccoli, corn kernels, asparagus and garlic tends to be minimal, Britt said.
If any PFAS is found on Aroostook farms in future years, the impact will likely vary from producer to producer depending on what concentrations are found, Britt said.
“PFAS testing can be very site specific. Local soil characteristics, crop types, water sources and management practices all play a role in the contamination and impact on production,” Britt said. “In many instances, producers are able to continue to farm.”
Martin wants his future research to better educate farmers on what their future might hold with PFAS.
As part of a $1.6 million EPA grant, shared with the Mi’kmaq Nation and scientific partners, Martin will continue water sampling and growing research crops the next four years. He also wants to study potential ways to extract PFAS chemicals from agricultural soils.
The Mi’kmaq Nation is already studying how to extract PFAS from soil using industrial hemp and then take the PFAS safely out of harvested hemp. Other methods for taking PFAS from soil and crops could involve fungi and or microbes within bacteria but those methods have received limited scientific research nationwide, Martin said.
“We want to find ways to remediate the soil, but PFAS doesn’t break down, so you can’t just burn or compost it,” Martin said. “So little is known about all of this within the scientific and [food] production communities, but we need to understand it.”
