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Issues Of The Environment: New Study Finds PFAS In Commonly Used Fertilizers

Jeff Gearhart
The Ecology Center

Gardening season is in full swing, and folks are ready to buy the essentials, such as natural fertilizers. Yet, buyers should beware. A national study conducted by the Ann Arbor-based Ecology Center and the Sierra Club found a number of top-selling fertilizers contain the "forever chemicals" known as PFAS. Jeff Gearhart is research director for HealthyStuff.org at the Ecology Center. He joined WEMU's David Fair to discuss the findings and the measures needed to protect us from these harmful chemicals.  


  • “Natural” garden fertilizers may contain PFAS. The Ecology Center and Sierra Club sampled different kinds of fertilizers made from biosolids. That’s the sludge left at a wastewater treatment plant after water is cleaned up. Almost all of them had PFAS compounds in them. 

  • Per- and polyfluoroalkyl substances (PFAS) are a class of thousands of chemicals widely used in manufacturing and consumer products. They are often referred to as “forever” chemicals, because their strong carbon-fluoride bonds don’t break down in nature. PFOS and PFOA were phased out in 2010, but continue to pollute our environment. Moreover, we are detecting newer PFAS in our water, soil, fish, and wildlife. They also cause a variety of serious health issues for people.

  • PFAS contaminated runoff makes its way into municipal water systems and contaminates drinking water. Ann Arbor spends thousands of dollars annually testing for PFAS in water, and much more attempting to remove most of it. Little testing has been done to see how much PFAS is taken up in different crops.

  • PFAS isn’t just a problem for home gardeners as biosolid fertilizers are increasingly used in agriculture. There is no regulation for PFAS in fertilizer, and the biosolids being sold in Michigan mostly originated from out of state. 

  • The Sierra Club and Ecology Center would like to see state and federal governments get serious about regulating PFAS and prohibit its use with a few exceptions. 


Some common garden fertilizers sold by major retailers have concerning levels of PFAS compounds, so-called "forever chemicals" that last in the environment for decades and potentially harm health, a new study has found.

The fertilizers in question contain biosolids — sewage sludge sold by wastewater treatment plants after it has been dried and treated for biological contaminants. But it's often not treated for per- and polyfluoroalkyl substances — PFAS — compounds used in a host of commercial products for waterproofing and grease resistance, as well as in many industrial applications. The PFAS compounds have been tied to cancer and other health problems.

It's not just a potential problem for those growing their own fruits and vegetables. The PFAS levels found in biosolids coming from wastewater treatment plants around the country point out the degree to which the chemicals continue to flow from industrial waste streams — and the lack of filtration at the factory or the wastewater treatment plant to remove the chemicals. The environmental nonprofits behind the study present Michigan as a model for other states to follow in identifying and requiring treatment from large industrial contributors of PFAS wastewater. 

For their research, the Ann Arbor-based environmental nonprofit Ecology Center, along with the Sierra Club, purchased nine garden fertilizers from eight states and the District of Columbia, and sent it to a contracted laboratory for PFAS analysis:

  • Pro Care All Natural Fertilizer, made up of 85.5% to 91.5% biosolids from an unknown source, purchased at Lowes
  • Ecoscraps Slow Release Fertilizer, made up of 100% biosolids from an unknown source, purchased at Home Depot
  • Milorganite 6-4-0 Fertilizer, made up of 100% biosolids from the Milwaukee Metropolitan Sewerage District, purchased at Home Depot
  • Cured BLOOM Soil Conditioner, made up of 100% biosolids from DC Water's Blue Plains Advanced Water Treatment Plant, purchased at W.S. Jenks & Sons in Washington 
  • Menards Premium Natural Fertilizer, made up of 100% biosolids from an unknown source
  • GreenEdge Slow Release Fertilizer, made up of 100% biosolids from the JEA sewer collection system in Jacksonville, Florida, purchased at Home Depot
  • Earthlife Natural Fertilizer, made up of 100% biosolids from the New England Fertilizer Co. of Quincy, Massachusetts; purchased at York Woods Tree & Products, Eliot, Maine
  • Synagro Granulite Fertilizer Pellets, made up of 100% biosolids from Sacramento (California) Pelletizer 
  • TAGRO Mix, made up of 50% biosolids from the Tacoma Central Wastewater Treatment Plant in Washington, purchased at Ace Hardware.

"Eight of the nine products exceeded screening limits for chemicals PFOS or PFOA set in Maine, the U.S. state with the most robust action on PFAS in biosolids," the study states. "The chemicals were measured at levels that would not be acceptable for the state's agricultural soils."
Only Synagro Granulite Fertilizer Pellets met the tough Maine standards for biosolids for both PFOS and PFOA. 

Home gardeners, therefore, might be adding another route for harmful PFAS compounds to enter their bodies through the fertilizers they use — often dubbed "natural" — and the fruits and vegetables they grow that absorb those compounds, said Gillian Zaharias Miller, senior scientist with the Ecology Center.

"The bigger message is, as long as we keep using products that use PFAS, like our waterproof clothing, our nonstick cooking utensils, and so many other commercial and industrial applications, we will have all of these chemicals come back to us," she said. "We can't get rid of them."

Though PFOS and PFOA, the most studied and understood of thousands of PFAS compounds, were detected in the blood of more than 99% of Americans sampled, the suspected source of PFAS turning up in biosolids from wastewater treatment plants is from industrial effluent.

There are no federal regulatory standards for PFAS compounds in drinking water or sewer sludge. The U.S. Environmental Protection Agency has begun to consider biosolids standardsfor PFOS and PFOA, a process that might take years.

Maine's standard — biosolids exceeding 2.5 parts per billion for PFOA or 5.2 parts per billion for PFOS are not allowed on agricultural fields — was developed after high-profile incidents where dairy and beef farms in the state were forced to close when milk from the farms tested with high levels of PFAS compounds. In a 2020 incident, a farm's milk tested had PFOS levels at 153 times Maine’s standard for determining that milk is “adulterated” and unfit for sale. The contamination was traced to cows feeding on plants that were grown on fields spread with PFAS-containing biosolids fertilizers.

Eight of the nine garden fertilizers tested by the Ecology Center and Sierra Club had levels of PFOS or PFOA that exceeded the Maine biosolids standard, and three exceeded it for both chemicals:

  • Cured BLOOM with 23.8 parts per billion PFOA, 22.1 PFOS.
  • Earthlife Natural Fertilizer with PFOA at 2.75 ppb, PFOS at 17.3 ppb.
  • TAGRO Mix at 7.51 ppb PFOA, 7.92 ppb PFOS.

None of those fertilizers sampled, however, would exceed Michigan's standards. Michigan in March presented an interim strategy for land application of biosolids containing PFAS. It calls for stepped-up testing of biosolids at wastewater treatment plants, prior to their application to fields.

"The state of Michigan’s approach for addressing PFAS in municipal wastewater and associated residuals (biosolids/solids) is to control significant industrial sources of PFAS, specifically PFOS/PFOA, before they are discharged to the" treatment plant, said Scott Dean, spokesman for the Michigan Department of Environment, Great Lakes and Energy.

Under Michigan's plan, biosolids with PFOS levels above 150 parts per billion cannot be applied. Those above 50 parts per billion but less than 150 require investigation of potential sources for the PFAS, and land application rates of no more than 1.5 dry tons per acre. Those above 20 parts per billion but below 50 parts per billion should "consider investigating sources and sampling the (wastewater treatment plant) effluent for PFAS."

Under Michigan's program to identify high PFAS levels at wastewater treatment plants, and determine the industrial sources upstream of those compounds, PFOS exceedances were reduced by 99% at four treatment plants: Ionia, Lapeer, Port Huron and Wixom, and by 92% to 96% at plants in Kalamazoo, Howell and Bronson. Treatment consists of granular activated charcoal filtration at the source of the PFAS.

"Michigan has paid some attention — more than a lot of states — to PFAS in all kinds of water, including wastewater," Miller said. "Its industrial pretreatment program has had some success in reducing the levels of those (PFAS) compounds in wastewater effluent. It's ignored in most states."

The Sierra Club and Ecology Center are calling for the federal government to "urgently act to end PFAS uses in commerce and releases from industrial sites;" for states to better regulate PFAS; for wastewater treatment plants to investigate sources of PFAS discharges into their systems, as Michigan does, and for agricultural producers to "not apply biosolids to their crop and pasture lands.

"Doing so risks permanently contaminating their soils with PFAS and other long-lasting chemical contaminants," the report states.

Gardeners are advised to check the "guaranteed analysis" on any fertilizers and consider avoiding those using terms like "biosolids," "residuals" or "municipal waste."

A message left with The Fertilizer Institute, an Alexandria, Virginia-based trade group for the fertilizer industry, was not returned Monday.

Linda Birnbaum, a toxicologist and former director of the federal National Institute of Environmental Health Sciences and National Toxicology Program, said the findings of the new study concern her.

"Some of (the PFAS) is going to be taken up by the root of the plant, some of it is going to be on the leaves, some of it is going to wash off and get into groundwater and surface water," she said. 

"Until we start reducing the input of these chemicals into the environment, we will continue to have problems." (Source: *directly quoted* https://www.freep.com/story/news/local/michigan/2021/05/25/pfas-pfos-forever-chemicals-garden-fertilizers/7418828002/)

PFAS Risks

Per- and polyfluoroalkyl substances (PFAS) are a class of thousands of chemicals widely used in manufacturing and consumer products. They are often referred to as “forever” chemicals, because their strong carbon-fluoride bonds don’t break down in nature. PFOS and PFOA were phased out in 2010, but continue to pollute our environment. Moreover, we are detecting newer PFAS in our water, soil, fish, and wildlife.

PFAS contamination is widespread in Michigan.

The Michigan PFAS Action Response Team (MPART), has found PFAS in bodies of water across Michigan. Over 2,000,000 Michigan residents live in areas with PFAS in their drinking water sources. Some major sites include:

  • Oscoda: Firefighting foam used at Wurtsmith Air Force base contaminated soil, ground and drinking water. A “do not eat” advisory was issued for fish in Clark’s Marsh and the Au Sable River and for deer around the base.
  • Ann Arbor and Huron River: Two automobile supply plants in Wixom that discharged PFAS into the Huron River, resulting in high levels in municipalities along the Huron River watershed and “do not eat” advisories for fish. Water in Ann Arbor exceeded EPA recommendations, requiring advisories and new filtration systems.
  • Parchment: PFAS levels 25 times the EPA’s recommended level were detected in drinking water and traced to an old paper mill that used PFAS to coat food-wrap paper.
  • Detroit: Marathon Petroleum Company used PFAS-containing firefighting foam in training and emergency response in Detroit's Melvindale neighborhood. As a result, groundwater tests in the area reported PFAS levels up to 46 times the state's MCL. 
  • Dearborn: The Rouge Manufacturing Complex in Dearborn, an automobile and steel manufacturing facility owned by Ford Motor Company and AK Steel, has been identified as a source of PFAS contamination in groundwater and stormwater. 

These are only a few examples of the many contaminated sites across Michigan:

In August 2020, the State of Michigan adopted new maximum contaminant levels (MCLs), limiting seven PFAS chemiclas in municipal drinking water. These new standards added 38 new sites to MPART's portfolio of ongoing PFAS investigations, bringing the number of groundwater sites in Michigan exceeding the PFAS MCL to 148. More information on these PFAS contamination sites can be found on the MPART website. These 148 sites only include groundwater investigations - there is even more PFAS contamination in Michigan. Sites with contaminated surface water or soil also exist across the state.

PFAS affects human health.

PFAS has been detected in human blood, semen, and breast milk. PFAS can cross the placenta, exposing unborn children. Studies of people exposed to high levels of PFAS have shown links to:

  • Thyroid disease
  • Immune disorders
  • Abnormal liver function
  • Abnormal cholesterol levels
  • Decreased fertility in men and women
  • Complications of pregnancy and abnormal development of children exposed in utero
  • Kidney and testicular cancer

Recent studies have shown that PFAS can mimic human hormones including thyroid, estrogen and testosterone, resulting in low function. One study looking at young men exposed to high levels of PFAS over long periods of time found lower testosterone activity resulting in smaller genitalia and lower sperm counts.

Evidence also suggests that PFAS chemicals may be exacerbating the effects of the novel coronavirus. Because PFAS suppresses the immune system, it could increase the risk of catching the virus. Concern also surrounds the possibility that PFAS exposure could limit the effectiveness of a COVID-19 vaccine. Studies have confirmed the association between PFAS exposure and reduced antibody responses and other adverse immune-related impacts. As the impacts of the COVID-19 pandemic continue to be felt in Michigan and across the U.S., it is imperative to reduce PFAS exposure to prevent further comorbidities. 

PFAS are impossible to avoid.

In addition to drinking water, fish and wildlife, PFAS are in food packaging, non-stick cookware, polishes, waxes, paints, cosmetics, cleaning products and many other goods. Plant foods grown in contaminated soil can take up the short-chain PFAS. Young children exposed to stain-resistant carpeting and water repellant surfaces can absorb PFAS from hand-to-mouth contact. PFAS levels can be detected in almost every human being on our planet. It is virtually impossible to get rid of PFAS:

  • Filtration systems remove some long-chain PFAS, but most are ineffective in removing short-chain compounds. Disposal of the filters in landfills can result in contamination of leachate that ends up in our groundwater. Incinerating filters results in discharge of PFAS into air. PFAS in surface water can end up in contaminated soil and sludge.
  • PFAS builds up in animals and humans. Studies have shown high levels of PFAS in human liver, lung, kidney, brain and testicles. There is no medically proven way to remove PFAS from our bodies.

What the Michigan Legislature Can do:

  • Focus on prevention, not just treatment, by banning the use of all firefighting foams containing PFAS and prohibiting the use of PFAS in food contact materials. Safer alternatives are available for use. 
  • Assure all state purchasing eliminates the purchase of PFAS-containing products where they are non-essential or when safer alternatives exist.
  • Provide adequate funding to continue testing for PFAS, remediation of contaminated sites, and treatment funds for water utilities and private well users to provide safe drinking water.
  • Create a publicly available database and maps of all known sites of contamination (PFAS and other contaminants of concern), along with test results as they are received.
  • Establish state medical monitoring and biomonitoring programs, the costs for which are to be covered by insurance and/or the party responsible for the contamination. 
  • Hold polluters accountable for contamination so municipalities and taxpayers are not left footing the bill. (Source: *directly quoted* https://www.ecocenter.org/facts-about-pfas)

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— David Fair is the WEMU News Director and host of Morning Edition on WEMU.  You can contact David at734.487.3363, on twitter @DavidFairWEMU, or email him at dfair@emich.edu

Contact David: dfair@emich.edu
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