PFAS chemicals are dangerous because they are highly toxic, very persistent in the environment, largely unregulated, and released into air, water, and land.
PFAS compounds are making it onto our farmlands and into our gardens.
This page explains how PFAS are collected by wastewater systems, run through treatment plants, and sent out to farms and gardens -- and what you can do about it.
Key Points.
Please scroll down for details on each point.
1. PFAS compounds are dangerous because they are highly toxic, persistent, and mobile in water.. More below
2. PFAS compounds are out of control due to widespread use, large numbers of compounds, and limited regulation More
3. PFAS compounds are released from many sources into wastewater systems that transport them to wastewater treatment plants. Wastewater treatment plants do NOT remove or destroy PFAS compounds. They are retained in liquids known as "wastewater residuals" and solids known as "sludge."
4. Sludge containing PFAS from wastewater treatment plants is sent to disposal sites or other uses including application to land and use in gardening products.
5. Evidence is emerging that applying biosolids to land can create hazards at farms and from farm products. So far, much of this evidence is from individual cases. Farms contaminated by PFAS and have been forced to discard food products or even to cease farming. Broader assessments are desperately needed.
6. The practices to distribute PFAS compounds after wastewater treatment are not regulated by the federal government. It is perfectly legal under federal law for a wastewater treatment plant to send PFAS to farmlands or home gardens.
7. Some states have begun to act. Maine, Wisconsin, and other states are beginning to put limits on application of biosolids or collect data about the topic.
8. Some wastewater system operators are concerned. Some are seeking to keep PFAS out of their waste streams. Many are monitoring for PFAS.
This site will track science and policy developments and opportunities for PFAS actions for local and state activists. Sign up for our email newsletter here. (Note: Signup will be activated soon)
Details for the Key Points
1. PFAS chemicals are dangerous
PFAS (Per- and Poly-fluoro alkyl substances) compounds are a group of manufactured chemicals that have been used in industry and consumer products since the 1940s. They are often referred to as “forever chemicals” due to their persistence in the environment. The three most important reasons that PFAS compounds are dangerous:
- Persistence in the Environment: PFAS are long-lasting chemicals that break down very slowly over time2. Some may not break down at all. Because of their widespread use and persistence, they can build up in people, animals, food chains, and the environment.
- Health Hazards: Exposure to even very low levels of PFAS comp0unds is associated with a higher risk of adverse health conditions. These include raised cholesterol levels; kidney, prostate and testicular cancer, asthma, thyroid disease, liver damage, and obesity. (Note: we are reviewing this list from ATSDR from other authoritative lists and may incorporate some other endpoints.)
- Mobility: Unlike most highly persistent compounds, PFAS tend to be highly mobile in water and so pose a greater risk to contaminate water bodies.
2. PFAS Compounds are Out of Control due to Widespread Use, Large Numbers of Compounds, Limited Regulation.
Widespread Use of Large Numbers of Compounds
- PFAS compounds are used in many products including packaging, clothing, textiles, fire-fighting foam, firefighters clothing, cosmetics and personal care products.
- PFAS are used at manufacturing industries including tanning, chemical production and others.
- PFAS have been used in fire fighting foam known as AAAF used in training for fire fighters as well as in extinguishing fires. Military sites, airports, ports, and fire training facilities often have very high levels of PFAS in surrounding water.
- There are tends of thousands of PFAS compounds. They are manufactured as mixtures. Researchers have described the overall qualities of PFAS pretty well. But the sheer number of PFAS substances makes it impossible to specifically describe the specific toxicities of every one one.
Limited Regulation by the Federal Government
- Unfortunately, the chemical industry has successfully demanded that traits of individual PFAS be specified before they are subject to meaningful regulation. This has perpetuated the broad contamination of people, water, air, biota, and land with dangerous PFAS compounds.
- Emissions of PFAS are not regulated by the US, nor are uses in products. PFAS can be freely emitted to air and water , and they can be dumped into landfills. They can be freely used in any product.
- EPA has adopted two major regulations regarding PFAS in April 2024.
- These are welcome steps, but they cover only a handful of PFAS compounds. Moreover, these rules do not directly stop uses and releases of PFAS. Moreover, costs for drinking water treatment to remove PFAS fall to those who operate the drinking water systems, often municipalities or regional governments.
3. Many sources release PFAS compounds into wastewater systems that transport them to wastewater treatment plants. These plants do NOT destroy the PFAS.
PFAS are used in many locations. As a result, PFAS are released at many locations. Often, PFAS are released into sewer and wastewater systems. Most are connected to larger wastewater systems that lead to a sewage treatment plant (also known as a wastewater treatment plans.)
There are more than 14,000 wastewater treatment plants in the US. (Ref1) Many of these are owned and managed by municipal or regional governments. Some are managed by businesses or the military. Many are older; updating and improving them is a goal of the Bipartisan Infrastructure Bill passed in 2023.
What these plants have in common is that they do not break down PFAS compounds. The same amount of PFAS that goes into a wastewater treatment plant at the beginning then goes out of the plant at the end of the treatment process. Sometimes the amount of PFAS may increase. Often, the exact types of PFAS that emerge are somewhat different from those that go in. But in either case, they continue to be just as dangerous when they come out as they were when they went in. (REFs2)
Wastewater treatment plants produce liquid and solid outputs. Here we are focused on the solid fraction. (However, there are also issues with the PFAS in the liquid fraction, known as wastewater residuals. These are addressed by a different Sierra Club team, known as Wastewater Residuals.)
4. Sludge from wastewater treatment plants is sent on to disposal sites or other uses including application to land and use in gardening products.
The leftover solids ( known as sludge) from wastewater treatment plants have to be sent somewhere. They accumulate over time, often at large volumes.
There are three options for sludge produced at a wastewater treatment plant:
a. Disposal through placement or burial at a solid waste facility (often known as a "dump") --
This has the advantage of moving the material away from the wastewater treatment plant. Solid waste facilities vary greatly in their ability to permanently contain the materials put into them. Most of them are located outdoors and subject to precipitation that leaches through the site. The severity of this is affected by weather. More precipitation tends to make it worse. The severity of leaching is also affected by the design and operation of the facility. Some facilities have advanced systems to monitor leaching and prevent the leaching liquids (known as "leachate") from leaving the site. Others do not.
Recent evidence suggests that quite a lot of PFAS may leach out of solid waste disposal facilities. We will post a separate resource page discussing this issue at a later date and link it here. This issue is not further addressed here.
b. "Disposal" through incineration or other "thermal treatment" option --
Additional explanation will be added here, but suffice it to say that neither incineration nor thermal treatment has been shown to actually destroy PFAS chemicals. These methods are most likely to re-distribute PFAS from the wastewater back into the air.
c. Use of sludge (or "biosolids") on lands or in products for uses considered by some to be "beneficial" --
Our focus here is on the export of sludge from wastewater treatment plants for uses on land or in products. Sludge is converted into "biosolids" by further drying and fluffing so that the biosolids are dryer and fluffier than the sludge. This can make them more tractable and appealing, though both the dryness and fluffiness seem to be quite variable.
Application of Biosolids to Lands
Land application this refers to transferring the biosolids onto land in a distrbuted way, such as by spraying.
This is not like placing biosolids in a solid waste facility, where they are not spread over a wide area. Rather, some kind of distribution method, which often means spraying, is used to distribute the biosolids over a wider area. There are two reasons for this.
- One reason is that the biosolids are considered by some to offer "beneficial" nutrients (such as nitrogen and phosphorous compounds) for soils. This is similar to fertilizers . There are limits to how much of such nutrients can be usefully absorbed by soils before they run off and contaminate surface waters. Nitrate contamination is a severe problem in many areas. But some degree of nutrient addition can be beneficial at the appropriate application rate.
- The second reason is to spread out any contaminants. These can include both microbes such as bacteria or viruses as well as chemical contaminants.
Concerns about chemical contaminants in biosolids applied to lands are not new. One concern that emerged nearly fifty years ago was about spreading toxic metals onto soils by use of biosolids. Metals of concern included mercury, lead, arsenic, and others. Such metals can be taken up into plants that could be sold as food for humans or that might be fed to livestock that such as beef cattle, dairy cows, or pigs.
In the 1990s, the concern about metals in biosolids led EPA to adopt rules to set limits on how much of the metals could be in biosolids that would be applied to land. (EPA5) (EPA6)
It also led to actions to get metals out of the wastewater sent to wastewater treatment plants.
Some of the same ideas are being considered for PFAS through permit conditions under the wastewater discharge permit program authorized under the federal Clean Water Act known as NPDES for the National Pollutant Discharge Elimination System.
Use of Biosolids in Products for Agriculture and other Land Use or for Gardening
A second option is for biosolids to be distributed for use in the production of products for agricultural, land management, or garden uses.
We are aware that biosolids may be used in products sold to golf courses for turf management.
We are aware that PFAS may be found in products marketed to gardeners and even in products marked as "organic." The Sierra Club Staff and PFAS team, in collaboration with The Ecology Center, did some testing and produced a report showing PFAS contamination in several products.
Please see the report on this work.
- Here is the Press Release from 2021.
- Here is the Full Report.
- Here is a fact sheet summary.
We are preparing additional information about this and will add it here when available.
5. Evidence is emerging that applying biosolids to land can create hazards at farms and from farm products.
Several cases have emerged where farm products or produce have been contaminated by PFAS. These will be summarized here.
News clip --
The EPA is cracking down on PFAS — but not in fertilizer. Farmers spread treated human waste on their crops. It's full of forever chemicals -- by Zoya Teirstein. Grist. 04.19.24. https://grist.org/agriculture/the-epa-is-cracking-down-on-pfas-but-not-in-fertilizer/
6. The practices to distribute PFAS compounds after wastewater treatment are not regulated by the federal government.
It is perfectly legal under federal law for a wastewater treatment plant to send PFAS to farmlands or home gardens.
EPA has included the topic of "biosolids" in its Roadmap for PFAS. This strategy includes actions for many areas where EPA has authority, as well as for developing methods and conducting research. It mentions PFAS in Biosolids, and there is a widespread impression that EPA has committed to taking action. However, this is not the case.
Rather, the Strategic Roadmap promises much less. The Roadmap commite only to conduct a risk assessment for the two legacy PFAS compounds -- PFOA and PFOS. These were some of the first PFAS chemicals to have been introduced. They are probably the most notorious due to well known effects.
EPA has taken the position that "there isn't enough data" to manage PFAS in biosolids. However, it is important to note that EPA has not committed to obtaining such data from the PFAS manufacturers nor to doing its own research. This seems like an empty excuse for inaction.
The language for the commitment made by EPA in the Roadmap is:
- Finalize risk assessment for PFOA and PFOS in biosolids that will serve as the basis for determining whether regulation of PFOA and PFOS in biosolids is appropriate.
Meanwhile, nothing has been released toward the promised risk assessment, which is now said to be due by the end of 2024. Nor is it clear how this risk assessment will be applied to make a determination for regulation of PFAS compounds in biosolids.
We are also looking into the review of a proposed broader framework for evaluating contaminants in biosolids considered by the Science Advisory Board in the fall of 2023. More will be reported later on that
7. Some states have begun to act. Maine, Wisconsin, and other states are beginning to put limits on application of biosolids or collect data about the topic.
See the Safer States website for information about state actions on PFAS overall.
More information about state actions and priorities will be added here
8. Some wastewater system operators are concerned. Some are seeking to keep PFAS out of their waste streams. Many are monitoring for PFAS.
More information will be added here.
This site will track science and policy developments and opportunities for PFAS actions for local and state activists.
You will be able to sign up for our email newsletter here.
(Note: Signup will be activated soon)
Sources of PFAS Compounds that Reach Wastewater Treatment Plans
This figure created by the Office of the Inspector General shows the many sources of PFAS that are gathered into wastewater systems and then transmitted to wastewater treatment plants. The treatment plants do not remove PFAS compounds, so what comes in then exits.
