PFAS in Michigan agriculture
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EmailRecent findings have demonstrated elevated PFAS levels in agricultural soils across the world due to inadvertent introduction through land application of materials containing high levels of PFAS.
Per- and polyfluoroalkyl substances, otherwise known as PFAS or “forever chemicals,” are a large class of manmade chemicals commonly used for their water, oil and stain resistant properties. These chemicals can be found in a wide range of products like firefighting foam, cosmetics, food packaging, non-stick cookware, carpeting, textiles and more. Due to their widespread use, these chemicals are found in water, soil, fish, livestock, pets, wildlife and humans around the world. PFAS chemicals have also been found on agricultural land, but more research and environmental sampling is needed to identify the extent of this contamination.
PFAS are still in use today and don’t break down significantly in the environment, but they can move, particularly through the water cycle. Some PFAS can build up in our bodies, which can lead to health risks. Therefore, breathing, drinking or eating food contaminated with PFAS is a concern. Research is still ongoing to fully understand the effects that PFAS have on health. Although more research is needed, some human health studies have shown that high exposures to certain PFAS may:
- Lower a woman’s chance of getting pregnant.
- Increase the chance of high blood pressure in pregnant women.
- Increase the chance of thyroid disease.
- Increase cholesterol levels.
- Change the body’s immune response.
- Increase the chance of cancer, especially kidney and testicular cancers.
How does PFAS get onto farmland?
PFAS have entered farmland through several different pathways including land application of materials containing high levels of PFAS, such as biosolids, paper sludge and tannery waste. Other pathways include irrigating with contaminated water and potentially through the application of pesticides, herbicides, septage and precipitation, although more research is needed to understand the extent of soil contamination resulting from these pathways.
Since 2021, Michigan has implemented a PFAS interim strategy to limit the land application of biosolids with high levels of PFAS. Prior to 2021, some biosolids may have contained high levels of PFAS and have been applied to some farmland across the state. For more information about PFAS in biosolids, farms or septage, please visit the Michigan State University Extension website PFAS Contamination in Agriculture.
What can be done about PFAS contamination in soil?
Recent findings have demonstrated elevated PFAS levels in agricultural soils across the world due to inadvertent introduction. The current methods available for PFAS remediation from soil, like excavation followed by incineration, are not feasible for large-scale agricultural usage. However, there is a lot of promising research on the horizon and management strategies are available to help deal with PFAS contaminated land. For example, some plants, such as grasses, readily uptake PFAS while others do not. Corn grain has repeatedly shown very little PFAS accumulation, however, the leaves do accumulate PFAS. If you have some contaminated fields, it would be better to grow corn grain on the land with higher levels of contamination and use the less contaminated land for harvesting corn silage, haylage or grazing animals.
Research on PFAS in agricultural systems is ongoing across the world, including at Michigan State University, however there is a shortfall of data in the literature on the bio-accumulation factors, transfer factors and the health effects on plants and livestock. Because the nature of PFAS could lead to uptake and bioaccumulation in plants and livestock, even low levels of PFAS in the soils or irrigation water could result in elevated concentrations within crops or animals.
PFAS in animal products
Research does suggest PFAS may build up over time in animal tissues and could be present in varying amounts in their meat, milk and eggs. In many cases, animals switched to clean feed and water have reduced PFAS secretion enough to again produce saleable products.
Currently, there are no federal or Michigan based food safety standards for PFAS, however, some states and countries do have regulations or guidelines in place. Michigan has fish consumption guidelines based on PFAS testing (and other toxins) in the Eat Safe Fish Guide.
Most food screening levels focus on PFOS (one of the more toxic PFAS chemicals) concentrations in milk, beef and eggs because that is where the most research has been conducted. In Maine, the Center for Disease Control set an action level of PFOS in beef (3.4 ppb), milk (210 ppt) and chicken eggs (4.7 ppb). These action levels guide the decision to allow a farm’s products to be sold in the commercial market. For comparison, in the Europe Union (EU), the regulatory threshold for beef is 0.30 ppb PFOS, and 1.0 ppb PFOS in eggs. There are also regulatory guidelines in place for three other PFAS chemicals (PFOA, PFNA, PFHxS) and the sum of the four chemicals.
The large difference between the thresholds in the EU and Maine is due to the use of different toxicity values in their calculations. A toxicity value measures a substance’s harmful potential and represents the amount a living organism can be exposed to before adverse effects occur. Expect these thresholds to decrease as more research is conducted and new toxicity values are adopted.
While the U.S. has initially focused on beef, milk and eggs, the EU also has regulatory food maximum levels for fish, crustaceans, pork, poultry, sheep and game and have investigative thresholds set for fruits, vegetables, starchy roots and tubers, food for infants and young children, wild fungi, milk and baby food.
Michigan State University Extension is here to help producers impacted by PFAS contamination. We can sample agricultural soils and have confidential conversations on determining the risk and strategies to mitigate PFAS contamination.
Please contact Faith Cullens-Nobis at 517-388-1078 or cullensf@msu.edu if you are a farmer and interested in more information.
