By Jared Hayes
Nearly 70 million acres of U.S. farmland could be contaminated by the toxic “forever chemicals” known as PFAS, according to estimates from biosolids industry groups. This contamination stems from the widespread use of sewage sludge as fertilizer.
The practice remains largely unregulated, despite mounting evidence it could contaminate food and water, creating public health risks. State and federal policymakers need to tackle this threat with steps such as banning the use of PFAS-contaminated sewage sludge on farm fields.
Sewage sludge, also known as biosolids, is the byproduct of the wastewater treatment process. The Environmental Protection Agency began regulating biosolids in 1993 under the Clean Water Act. Since then, EWG and others have raised concerns about using biosolids in food production.
Using industry surveys, the National Biosolids Data Project estimates that about 18 percent of all U.S. agricultural lands could be using biosolids as a fertilizer, even though the sludge is often contaminated with PFAS. This creates dangers for the food supply on the almost 70 million farmland acres – equivalent roughly to the size of Nevada where biosolids are used.
The industry findings add to concerns raised in a recent EPA risk assessment of how sludge used this way might add PFAS into the food supply.
The industry estimate included only one type of biosolids, known as Class B. Class A biosolids aren’t included in the estimate, because they don’t require permits or reporting. So PFAS contamination may be far more pervasive than the study suggests.
PFAS, which are called “forever chemicals” because they build up in our bodies and never break down in the environment, cause a broad range of health harms. Very low doses in drinking water have been linked to suppression of the immune system and are associated with an elevated risk of cancer and reproductive and developmental harms, among other serious health concerns. Ingesting PFAS from contaminated food is another way people are exposed.
A toxic pipeline from sludge to food
Industrial discharges of PFAS, along with PFAS-laden waste from residential areas, flow into wastewater treatment plants. The wastewater treatment process separates liquids and solids, creating sewage sludge as a byproduct.
But this process doesn’t remove PFAS, so the chemicals end up in both the solid sludge and also the treated liquid, which can contaminate drinking water supplies. And federal rules limiting pathogens and metals in sludge do not apply to PFAS.
After the treatment process, the utility can then choose to put the sludge in a landfill, incinerate it or sell it to farmers who use it as fertilizer on their land. The sale of sludge is in some cases completed through third-party companies who are responsible for managing the sludge.
There are no national requirements to test biosolids for the presence of PFAS or warn farmers they could be using contaminated sludge on their crops.
Widespread problem
In 2023 alone, nearly 4.5 billion pounds of sludge were applied to farm fields or used in compost, according to state reports filed with the EPA. The states that produced the most sludge intended for use on farm fields include California, Florida and Illinois. But sludge can be transported and applied in other states.
Once PFAS-contaminated sludge is applied as a fertilizer, the forever chemicals can leach into food crops, and crops of animal feed, such as corn and hay. Then it can also be absorbed by animals that eat these feed crops.
Some PFAS are more likely to build up in sludge, studies show. Once applied to the land, PFAS in sludge can be absorbed by edible plants, although how much so can vary, depending on the amount of PFAS and type of plant.
These chemicals in sludge can also leach into water and contaminate drinking water sources or water used for watering animals.
Several farmers have been forced to euthanize their farm animals due to high levels of PFAS in farm products, in some cases losing significant parts of their livelihood or their entire farm.
Tackling contamination
Several states, including Maine and Michigan, have found high levels of PFAS in sludge and taken action. For example, Maine has prohibited the use of sludge on farm fields. It also developed a detailed map of sludge applications, which shows landowners whether sludge was used on or near their property.
Although the EPA set limits on several PFAS in drinking water last year, there are no limits on the amount of PFAS that can be found in food. To address consumer concerns, the Food and Drug Administration should move quickly to set action levels for PFAS in food, as other nations have done.
Because of the risks of PFAS-contaminated biosolids, policy leaders must also end the use of this sludge on fields used to grow food and feed crops.
The presence of PFAS in biosolids is the result of polluters sending their industrial waste to our treatment plants and the unnecessary use of PFAS in everyday household products. States and the federal government should require polluters to pretreat their PFAS wastes before they are sent to wastewater treatment plants. And the EPA should immediately propose limits on PFAS discharges from industrial polluters.
Farmers also need to see the creation of programs that will help them with the costs of cleaning up millions of likely PFAS-contaminated acres. And Congress should protect farmers from any efforts to block their ability to recoup cleanup costs or damages from polluters and bad actors.
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