Per- and Polyfluoroalkyl Substances (PFAS)

The Maine Department of Agriculture, Conservation and Forestry (DACF) is committed to ensuring a safe food supply in Maine and supporting our vibrant agricultural community. DACF is taking a leading role in responding to the chemicals known as per- and polyfluoroalkyl substances (PFAS) in agriculture.

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What is PFAS?

PFAS are man-made chemicals that repel oil, grease, water, and heat. They became widely used in household products and industrial settings as early as the 1950s and have been used in firefighting foams due to their effectiveness at quickly extinguishing petroleum-based fires.

The PFAS chemicals perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) have been used to make a host of commercial products including non-stick cookware, stain-resistant carpets and furniture, water-resistant clothing, coated oil resistant paper/cardboard food packaging (like microwave popcorn and pizza boxes), and some personal care products.

What's the risk?

PFOA and PFOS are widespread and persistent in the environment. Studies suggest that these chemicals may affect cholesterol levels, thyroid function, birth weight, liver function, infant development, the immune system, and may increase the risk of some cancers including prostate, kidney, and testicular cancers. Health agencies are working to understand more about the health effects of low level, long-term exposure.

What's the impact to agriculture?

Agriculture and PFAS chemicals can intersect through air, water, and soil. One way that PFAS may enter soil is through the application of residuals such as biosolids, industrial sludges and ashes. The application of residuals on agricultural land is a common tool in agriculture as they contain nutrients and other organic matter that can enhance soils and agricultural production. It is a permitted and regulated activity by the Maine Department of Environmental Protection (DEP).

Residuals are created during the waste water treatment process and it is now understood that PFAS chemicals can end up in them from everyday household activities as well as from industrial sources. The sludge, when applied to farmland, contains PFAS substances which can enter soil and water, and be taken up by the crops grown on the field, and also into the animals eating those crops. The level at which PFAS contaminants are taken up is highly variable, depending on the amount spread, the PFAS concentrations in the soil and water, the type of plant(s) grown, the type of soil, and other factors.

Source: https://www.eea.europa.eu/

Unfortunately, no scientifically proven remedial method exists to remove PFAS chemicals from soils at this time.

Is food safe?

The US Food and Drug Administration conducts national food sampling studies for PFAS contaminants. FDA has stated that its "ongoing testing of samples from the general food supply has resulted in very few having detectable levels of PFAS, and after assessing the potential health risk, we have no scientific evidence indicating a need to avoid any food in the general food supply." However, FDA does acknowledge that PFAS can be found in food where localized contamination may have occurred. More from FDA about PFAS in food.

What is the Maine DACF doing?

DACF has been investigating PFAS contamination on farms, with the focus initially on dairy farms. In 2016, milk at a dairy in Arundel, Maine was found to contain high levels of PFOS. The Maine CDC created an Action Threshold for PFOS in milk: 210 parts per trillion (ppt). Since then, DACF has conducted statewide retail milk samples three times. Where results appeared to indicate that source milk might contain high levels of PFOS, DACF worked with processors to successfully identify a contaminated farm in Fairfield, Maine. DEP water testing resulting from that discovery detected a second PFOS impacted dairy farm also in Fairfield. Learn more about DEP's Fairfield investigation.

When DACF finds milk that exceeds the current Action Threshold, the farm must immediately cease selling milk. DACF, in coordination with DEP and Maine CDC, then works to identify the source(s) of the PFAS on the farm and identify strategies to reduce exposure so that PFOS levels in milk drop to once again be safe for human consumption. Given our current understanding of how PFAS transfers from forage crops into milk, DACF has been able to work with one of these farms to successfully reduce the PFOS in milk to below the state’s Action Threshold.

Thus far, no federal standards have been created regarding PFAS contaminants in food. This has led Maine to derive a current beef PFOS Action Threshold for beef at 3.4 parts per billion (ppb). There also currently is no established ability to test live animals to ascertain PFAS levels with certainty. Scientific literature and some initial studies suggest that PFAS accumulates more in leafy greens, grasses, and legumes but less so in fruits (such as tomatoes) and grains (such as corn).

A list of Maine's existing screening levels for PFAS is available (PDF).

Where PFAS contamination is confirmed in the soil and/or groundwater at a farm above screening levels, DACF will test products, additional farm fields' soils, water sources, and feed to determine and monitor levels of contamination. Our goal is to identify, then limit, or eliminate the PFAS in impacted products.

DACF's current budget allows the agency to pay for sampling efforts at these confirmed farms and, in some situations, indemnify the producer for the loss of the value of their crop or livestock. For dairy farms with milk contamination, the USDA's Dairy Indemnification Payment Program may be an option to receive compensation for the loss of income due to stopping milk production.

Starting in November 2021, the DEP began initiating its investigation into the presence of PFAS as a result of the land application of sludge and/or septage in communities around Maine. The DEP prioritized these sites located around the state into four Tiers (I, II, III, IV) to designate the approximate schedule for sampling. Tier I sites will be sampled first. Due to the large number of locations to sample,  the investigation of Tier I sites may extend through the first half of 2023. DEP must complete its testing of all sites by 2025. DACF is working closely with DEP to assist with any site that may be an active agricultural operation.

If you are a producer and have questions regarding your farm and PFAS, please email Duncan Pfaehler at duncan.pfaehler@maine.gov.

Self-testing

Producers concerned about potential PFAS contamination in their fields or water can self-test. However, because PFAS are found in clothing and other common products, sampling must be conducted very carefully and according to certain protocols. The DEP has helpful sampling instructions for groundwater (PDF).

Soil sampling is also a specialized effort. As a result, it may be useful to work with a third party that is skilled in soil sampling and familiar with PFAS protocols.

Testing can be expensive – not only for the appropriate bottles and gear necessary to take the sample but also for shipping and for laboratory analysis. In total, individual tests may be $200-$500. The DEP’s list of laboratories accredited in PFAS sampling is available (PDF). Battelle Laboratory can analyze muscle tissue and plant tissue. Guidance on interpreting water testing results is available (PDF). Interpreting other results may require the assistance of a third party familiar with PFAS and agronomy. 

An evolving situation

More research is needed to understand how PFAS accumulates in certain plants cultivated in PFAS contaminated soils or water and to determine safe levels for consumption. However, because people typically eat a variety of foods in their diet, the risk of unsafe exposure to PFAS due to occasionally eating foods with PFAS is likely low. However, these chemicals can accumulate in the body, and people can be exposed from a variety of sources given how ubiquitous PFAS are in society. People should try and minimize known PFAS exposures whenever possible.

DACF, DEP, and Maine CDC are all working hard to advocate for additional federal support to propel the understanding and science around PFAS forward and establish additional supports for impacted homeowners, municipalities, and farmers. We are also collaborating with other states to continue to learn more about ongoing PFAS research and studies.

Additional information


Information Disclaimer: The information provided on this web site is only intended to be general summary information for the public. While the Department of Agriculture, Conservation and Forestry strives to make the information on this website as timely and accurate as possible, the department makes no claims, promises, or guarantees about the accuracy, completeness, or adequacy of the contents of this site, and expressly disclaims liability for errors and omissions in the contents of this site.