You could be spreading ‘forever chemicals’ on your garden. Here’s how to protect yourself.

These persistent chemicals, which can linger in the environment for years, can taint crops, water and soil. They have been linked to a variety of health issues including cancer, infertility and thyroid problems.

The EPA’s findings come from a study focused on agricultural usage, in which biosolids are applied to less than 1 percent of fertilized acreage of agricultural land a year. But the agency said applying biosolids-based products to home gardens could lead to PFAS contamination, with risk varying based on the amount of fertilizer used and how much of the chemicals it contains.

Experts say it’s difficult to quantify how exposure from using these products at home could affect your health and the environment, but there are things you can do to protect yourself. Here’s what you need to know.

How do I know if my fertilizer contains PFAS?

Research has detected PFAS in home fertilizers, including some that don’t contain biosolids. But experts say amounts vary between products, noting that just because a fertilizer has PFAS doesn’t mean it contains enough to pose environmental or health risks.

Fertilizers typically don’t say on the label if the product contains PFAS. But packaging could indicate that the fertilizer is biosolids-based or derived from the sludge, which increases concern that it might be contaminated with the long-lasting chemicals, said Denise Trabbic-Pointer, co-author of a 2021 study from the Sierra Club, an environmental nonprofit, that analyzed products you can find in home-improvement stores and nurseries.

“PFAS in biosolids are at a much higher level than, say, if they use manure or something like that,” Trabbic-Pointer said. “They’re even finding PFAS in manure, but the levels are so much lower.”

The Sierra Club analysis tested for PFAS in nine samples of fertilizers marketed to home gardeners, focusing on the two most commonly detected types of forever chemicals — PFOA and PFOS. The study found the chemicals in all the fertilizers tested, with eight out of the nine samples containing levels that exceeded a screening standard set for application on farms in Maine, which at the time had the strictest safeguard of its kind in the country.

While the levels of PFAS contamination associated with repeated home use probably aren’t as high as direct land application of biosolids on a farm, “they’re still of concern,” Trabbic-Pointer said.

People can also be exposed to these long-lasting chemicals from other sources as they go about daily life, she added.

“Say you live in an area where there’s industry, and you’re breathing in, say, three different chemicals at certain times of the day, and then there’s another four or five in your drinking water,” she said. “It all builds.”

What are the risks?

Using fertilizers with PFAS could contaminate soil as well as surface and groundwater, exposing people to the chemicals. But these risks depend heavily on how the fertilizers are applied.

The EPA notes that home gardens are generally much smaller than a field used for growing crops. Given the size of residential garden beds, using biosolids there might not carry the same environmental concerns, though risks can increase if larger amounts are applied in bulk, according to the agency.

The report also said there is a “high degree of uncertainty” about how much PFOA and PFOS is absorbed by fruits and vegetables grown in these gardens. Some research suggests that leafy greens, such as spinach and lettuce, are more likely to absorb the chemicals. The EPA added that a home gardener could apply enough biosolids, potentially over multiple years, to raise the amount of the chemicals found in soil, leading to an increase in what is absorbed by fruits and vegetables. It is also possible that people with backyard chickens could find the chemicals in their eggs if vegetable scraps, soil, grubs and grass are contaminated.

Michael Mashtare, an assistant professor of agricultural and biological engineering at Penn State University, said home gardeners shouldn’t expect the same level of contamination the EPA study found on farmlands where biosolids were used. “I don’t believe I’ve seen anything to make those connections,” said Mashtare, who has researched PFAS in fertilizers.

And some experts say it’s important not to overlook the benefits of waste-derived fertilizers. “The reuse of our waste as a way of meeting the nutrient needs and increasing soil properties … I think is incredibly important,” Mashtare said.

“Where it becomes complex is, yes, there are great benefits,” he added. “But then we often have sort of rising concerns because depending on where that waste is coming from, there can be contaminants.”

What can I do?

If you’re concerned about your fertilizer containing PFAS, Trabbic-Pointer recommends switching to products that are verified by the Organic Materials Review Institute, a nonprofit organization that provides independent reviews of fertilizers, pesticides and livestock-care products.

“They won’t certify anything that contains biosolids,” Trabbic-Pointer said.

But people who are using biosolids-based fertilizers might be reluctant to give them up.

“Our plants love those commercially available biosolids,” said Linda Lee, a professor of agronomy at Purdue University who has researched PFAS in fertilizers. “They really do wonders for our garden.”

If you’re going to keep using these products, it’s critical to follow application instructions.

You can further reduce risk by opting for fertilizers with high nutrient concentrations, meaning you won’t need to apply as much, Lee said. Check to see how much nitrogen a fertilizer product contains. For additional help choosing a fertilizer, experts recommend contacting your local university’s extension program.

She added that unlike with leafy greens, not many of the types of PFAS that can build up in people’s bodies transfer to fruits, such as tomatoes and berries. You can take additional precautions, including peeling root vegetables and tubers.

Exposure can also be limited by wearing gloves or a mask when you’re applying products, she said.

But figuring out how to reduce risk shouldn’t fall to consumers, Mashtare said.

“People should be able to make an informed decision in terms of what we are applying to our gardens,” he said. “There does need to be more transparency in terms of the type and source of wastes in waste-derived fertilizers.”