People could unknowingly spill “forever chemicals” on their lawns and gardens in the form of fertilizers sold across the country, including the famous Milorganite of Milwaukee.

A study by the Sierra Club and the Michigan Ecological Center discovered that Milorganite was one of many fertilizers containing PFAS. All fertilizers are at least 50% biosolids – treated sewage sludge – rich in nutrients useful for growing grasses, fruits and vegetables.

MMSD has been selling Milorganite as a commercial fertilizer since 1926 in the United States and Canada, and on its website, the product is touted as “one of the oldest recycling efforts in the country.”

Aside from Milorganite, eight other fertilizers have been tested, and most have been purchased from places like Lowes and Menards, where most people access similar products. All of the produce contained varying levels of PFAS, which means that fruits and vegetables fertilized with the produce can absorb the chemicals as they grow.

“PFAS in fertilizers could make vegetable crops a source of exposure for home gardeners,” the report said.

The researchers recommended that home gardeners refrain from using biosolids-based fertilizers on their plants to minimize the risk of chemical exposure.

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But PFAS in fertilizers is not only a problem for those who grow their own fruits and vegetables. Experts said the PFAS found in wastewater treatment plants likely came from elsewhere, which means industrial users are still not properly filtering harmful compounds from their waste streams before releasing them into the system. sanitation.

PFAS, or per- and polyfluoroalkylated substances, are a group of synthetic chemicals used for their water and stain resistance qualities in products such as clothing and rugs, non-stick cookware, packaging and fire-fighting foams.

The chemicals are persistent and remain both in the environment and in the human body over time. The build-up of chemicals in the body has been linked to cancer, studies have shown, or to other adverse health effects.

The researchers tested the fertilizers for 33 PFAS compounds, including two of the best known – PFOA and PFOS.

The tests included:

  • ProCare Natural Fertilizer, purchased from Lowes, made from 85% to 91% biosolids from several locations in Georgia.
  • EcoScraps Slow Release Fertilizer, purchased from Home Depot, made with 100% biosolids from unknown sources.
  • Milorganite Fertilizer 6-4-0, purchased from Home Depot, 100% Biosolids from the Milwaukee Metropolitan Sewerage District.
  • Dried Bloom Conditioner, purchased from a store in Washington DC, made from 100% biosolids from the Blue Plains Advanced Wastewater Treatment Plant in Washington DC
  • Menards Premium Natural Fertilizer, purchased from Menards, made from 100% biosolids from unknown sources.
  • GreenEdge Slow Release Fertilizer, purchased from Home Depot, made with 100% biosolids from the JEA Sewer Collection System in Jacksonville, Florida.
  • Earthlife Natural Fertilizer, purchased from a store in Eliot Maine, made with 100% biosolids from the New England Fertilizer Company in Quincy, Massachusetts.
  • Synagro Granulite fertilizer granules, purchased in Sacramento, Calif., 100% biosolids from the regional Sacramento wastewater treatment plant
  • TAGRO mix, purchased from Ace Hardware, which is 50% biosolids from the central wastewater treatment plant in Tacoma, Wash.

The study compared the fertilizers to Maine’s standards for PFAS in biosolids, the state with the most robust action for chemicals in biosolids, the document notes.

“These ‘eternal chemicals’ were found in nine products tested by the Ecology Center of Michigan and the Sierra Club and marketed as ‘green’ or ‘natural’ and eight of the nine exceeded state-set testing levels from Maine. ”says the report.

Wisconsin has currently only recommended standards for certain PFAS compounds in ground, surface, and drinking water as determined by the state Department of Health. Lawmakers have yet to pass legislation on chemicals in water, and no action has yet been taken on limits for biosolids in the state.

Tom Nowicki, an attorney for MMSD staff, said just because PFASs have been found in Milorganite doesn’t mean there is a risk to users.

“The fact that they’re in biosolids is no surprise,” he said. “The question to be answered is to what extent a risk is caused, and studies are underway to measure the transport of PFAS in biosolids. ”

This is not the first study to raise concerns about the level of PFAS in Milorganite.

In 2019, Maine and Massachusetts raised questions about the levels of perfluorinated chemicals in fertilizer. Maine halted fertilizer sales for a while until tests confirmed PFAS levels were low enough to meet new state standards.

No state currently bans Milorganite, MMSD officials said.

Since then, Vermont, New Hampshire and Michigan have also started testing biosolids for PFAS, the study found, and Colorado has implemented PFAS standards that will likely lead to permit restrictions for industrial sources. chemicals. Testing biosolids is important because not only are they introduced into fertilizers, but they are also regularly spread on farmland, including crops and the grass that cows graze on.

PFAS have already manifested themselves in biosolids in Wisconsin.

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In Marinette, biosolids from the town’s sewage treatment plant that were spilled on the fields contaminated the wells of some farmhouses. The results prompted the DNR to further test wells in a larger area of ​​agricultural land.

The Marinette-Peshtigo area has one of the worst PFAS contaminations in the state, due to years of outdoor testing of fire-fighting foam containing the chemicals. The foam was produced by Tyco Fire Products, a subsidiary of Johnson Controls, and sprayed onto concrete during testing before being discharged into the sewer.

In 2019, the DNR asked the operators of 125 wastewater treatment plants, including the MMSD, to test more than 30 PFAS compounds in their sludge. In the Milwaukee metropolitan area, the request was also directed to the city of Brookfield, Fredonia, Grafton, Hartford, Jackson, Saukville, South Milwaukee, Waukesha and West Bend, since MNR said these communities are more likely to receive wastewater from companies who knowingly or unknowingly use PFAS.

The solution starts with the industry

However, there are ways to make sure that the “chemicals forever” don’t end up in the fertilizers people use in their gardens.

The study suggested a number of solutions, including further testing of water discharged by industrial users to treatment plants and reducing the use of biosolids fertilizers. But the most important steps to regulate chemicals in biosolids would be legislation at state and national levels.

Gillian Miller, a senior scientist at the Michigan Ecological Center, said she hopes the study will prompt state lawmakers across the country to enact regulations on how much of the chemicals can be found in sludge and water. . Have wastewater treatment plants test the water flowing from the facility for PFAS and try to find the source of PFAS “upstream”.

The action shouldn’t be left to ordinary people, however, she said.

“It’s a global problem,” Miller said. “Making choices at the consumer level won’t stop this.”

Nowicki, of MMSD, also hopes the study will spur action in Wisconsin to regulate upstream industrial use of chemicals. MMSD is just a passive recipient of chemicals, he said, and is not causing the problem.

“The way to solve the problem is to prevent it from entering the economy in the first place,” he said. “We are helping people talk to their legislators and try to take action there to eliminate these kinds of products.”

Sonya Lunder, senior toxic substances policy advisor for the Sierra Club, said that right now, without legislation, the burden is on ordinary people to choose different fertilizers or figure out how to deal with PFAS already. present in their soil or water. But that shouldn’t be the case, and if governments embrace some of the report’s suggestions, it could be a good first step.

“People are really stuck with the exposure,” she said. “And these solutions are not just for one agency. Several things will have to happen to contain this crisis.”

Laura Schulte can be reached at and on Twitter at @SchulteLaura.

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