Getting away from exposure to dangerous chemicals in food is a reason many people take up gardening in the first place.
But studies have shown that widely available commercial garden fertilizers made from treated solid waste contain levels of the toxic chemicals perfluorooctanesulfonic acid and per- and polyfluoroalkyl, also known as “forever chemicals” or PFAS for short.
Mainers have become increasingly worried about them ever since Songbird Organic Farm in Unity announced in January it was pausing sales after learning its soil, water and produce were contaminated with forever chemicals. A 2021 study found that many common home fertilizers contain high levels of PFAS, the use of which could lead to the presence of forever chemicals in food grown with them.
The problem is, there are no established guidelines of how many forever chemicals are too many in commercial fertilizers when it comes to public health. The only established forever chemical guidelines for sludge in Maine are the levels on what is spread on agricultural land.
Lacking those guidelines for safe or acceptable levels of forever chemicals in fertilizers, it’s up to the gardening public to determine for themselves what is and is not acceptable.
Caleb Goossen, organic crop and conservation specialist with the Maine Organic Farmers and Gardeners Association, said he recognizes that people are concerned about forever chemicals when it comes to their food, but said when it comes to what is grown in Maine, things may not be that bad.
Goossen said what he has seen with recent testing of fertilizers is indicating low or no levels of PFAS.
“What I have been seeing from what’s being tested are [no forever chemicals] or low levels being detected,” Goossen said. “There is always the potential it could have PFAS and that would be an issue for that one fertilizer.”
That’s why it’s important for consumers to ask fertilizer manufacturers about any testing they have done for the forever chemicals in their products. And to ask them why if they have not tested.
“It’s not a given they will find PFAS in their fertilizer,” Goossen said. “Asking the manufacturer if they are testing will indicate to those manufacturers there is a demand for the testing.”
It’s the same with compost, according to the Maine Organic Farmers and Gardeners Association.
“The widespread low-level PFAS contamination of our environment means that a sensitive testing protocol is likely to find some amount of PFAS in all composts,” according to MOFGA’s website. “There is no available guidance yet as to what may be considered a safe test result.”
Because of that, MOFGA is urging people to ask the source of their compost if it has been tested and then decide if it’s worth the risk of using it.
Those are the same questions people will need to ask themselves when it comes to fertilizer, Goossen said.
“I’m really not sure what else people can do at the moment,” he said. “It’s still too early to know much else.”
He said people’s awareness of forever chemicals, where they have been spread and taking steps to avoid areas of high contamination are helping produce safer food in Maine.
“Essentially we already have a safer food growing system than we did five years ago,” Goossen said. “The spreading of sludge occurred 40 years ago and nothing on the ground has changed since then.”
The PFAS chemicals are known as “forever chemicals” because of how long they take to completely break down in the environment and in the human body. They are used in industrial and household products and have been found to pose health risks in humans.
As for the upcoming gardening season, Goossen said there is every reason to plant this year.
“I would suggest things are likely to be safe,” he said. “I’m going to be gardening.”