Researchers have identified locations in Maine that test high for levels of so-called forever chemicals, but the effect on food grown in contaminated soil remains uncertain.
That’s why University of Maine researchers are partnering with Maine organic farmer Sue Hunter whose land is highly contaminated with the toxins. They hope to determine how much or how little specific crops absorb the toxins.
Since the 1940s, per- and poly-fluoroalkyl substances — PFAS for short — have been used in everything from waterproof materials to non-stick cookware. The substances are useful as coatings due to superior durability. But that’s also why PFAS don’t readily break down in the environment or the body, earning the nickname forever chemicals.
PFAS have been linked to a number of human health issues including cancer, kidney malfunction and low birth weights.
The research is focusing on three specific areas — how PFAS are absorbed by forage crops, how the chemicals are absorbed by specific market crops and if the addition of charcoal-like substance to the soil could prevent the toxins from getting into the plants at all.
“These projects are not similar to anything being done in Maine so far,” said Rachel Schattman, assistant professor of sustainable agriculture at the University of Maine School of Food and Agriculture. “There is research going elsewhere in the country, but it’s looking at the big commodity crops.”
Most of that work is happening in controlled greenhouses, and not on actual working farmland.
The UMaine researchers feel that it’s more important to look at crops grown by smaller, diversified farmers and homesteaders, Schattman said.
In her own part of the study, Schattman is looking at uptake rates of PFAS in tomatoes, corn and the ornamental grass fescue. She planted some test plots at the farm with a combination of the three and others with the individual plants.
In early 2022, Hunter had her land tested by Northern Tilth in Belfast. She and her son collected dozens of water and soil samples from around the farm, hoping to learn exactly where and how much PFAS was on their 150 acres. It turned out most of the property had varying levels of contamination. All operations were immediately halted on the farm.
Given the PFAS variability around the farm, Schattman said Hunter believed her land could be of use for researching the toxins. She was eventually put in contact with the UMaine researchers.
“Setting up an experimental condition with variable PFAS levels and past data collection like Sue has on her farm would take millions of dollars and decades to create,” said Diane Rowland, dean of the UMaine College of Natural Sciences, Forestry and Agriculture and director of the Maine Agricultural and Forest Experiment Station. “The property is perfectly suited to the types of questions that we need to ask and answer about PFAS.”
At the end of this growing season, Schattman said she will harvest the tomatoes, corn and fescue and send everything off to an out of state lab for PFAS level testing since there is no facility in Maine that can do it.
Once they get the results back, the winter will be spent analyzing.
“We do know there are a collection of mechanisms plants use to uptake PFAS,” Schattman said. “It comes up through roots into the leaves.”
Just how much of the PFAS end up in the different plant parts is one thing she hopes to determine. She will compare the amount found in the vegetables against the levels of the soil they were planted in.
Schattman said she has reviewed dozens of studies conducted in controlled environments nationally and internationally like laboratories and greenhouses. Those results indicate that most PFAS ends up in the leafy parts of plants with far lower levels in the fruiting parts.
“That means crops with big leaves like lettuce or kale where we are eating those leaves could pose a higher risk,” Schattman said. “But crops where you are eating the fruit like tomatoes or corn could be at a much lower risk.”
She included fescue in her study to determine if the grass competes for PFAS with other crops planted nearby.
“We want to see how something like fescue may serve as a ‘hyper-accumulator’ to pull in all the PFAS,” Schatmann said. “That might make it possible to grow crops alongside it.”
Schattman is the first to say there is far more that is not known about how PFAS gets into the food chain than is known, but said the work at the Hunter farm is a good starting point.
“I used to be a commercial vegetable farmer and I am managing my study plots as close to small scale farming as possible,” Schattman said. “The ultimate goal is to get information that is useful for the farming community.”
