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. The chemicals known as per- and polyfluoroalkyl substances (PFAS) and their potential effects on Maine agriculture are being carefully studied by DACF.

What is PFAS?

  • Perfluoroalkyl and polyfluoroalkyl substances (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 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 are the risks?

  • PFOA and PFOS are widespread and persistent in the environment and health agencies are working to understand the health effects of low level, long term exposure. Studies suggest that these chemicals may affect cholesterol levels, thyroid function, birth weight, liver function, infant development, and the immune system.

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 permitted and regulated by the Maine Department of Environmental Protection (DEP).
  • Residuals contain nutrients and other organic matter that can enhance soils and agricultural production. PFAS chemicals can end up in a waste water treatment plant’s sludge from everyday household activities as well as from industrial sources.

Is Maine milk safe?

To determine the safety of Maine’s current overall milk supply:

  • DACF completed a state-wide retail milk survey in June 2019 of Maine-produced fluid pasteurized milk. The results demonstrated that all samples were below the laboratory reporting level of 50 ng/L. The survey focused on Maine-produced milk that is either bottled in-state or is bottled out of state but sold in-state. Twenty-six samples were taken throughout the state to ensure broad geographic representation and population centers.
  • DACF estimates that this sampling captured 75% of all milk sold in Maine.
  • The Department also tested three commercial dairy farms, two with a history of biosolid and/or paper mill residual applications and which had soil samples that exceeded DEP’s screening levels for PFOA and/or PFOS. The third farm was near the farm that had tested high for PFOS in 2016. Milk sampled from all three farms were also below the lab’s reporting level of 50 ng/L.
  • Based on the retail milk survey and these three individual farm results from 2019, DACF had high confidence in the safety of Maine-produced milk.
  • DACF conducted a second state-wide retail milk survey in February 2020 of Maine-produced fluid pasteurized milk. The laboratory reporting level had improved to 25 ng/L.  Once again, the focus was on Maine-produced milk either bottled in the state or bottled out of state but sold in Maine.
  • Nineteen of the 20 retail samples taken returning results that were below the laboratory’s reporting limit of 25 ppt, providing confidence in the overall Maine product.
  • DACF investigated one retail milk sample with a 65.7 ppt result, and, with cooperation from the milk processor, was able to trace the source directly back to a farm whose milk, upon testing, had results of 12,700 ng/L, 14,900 ng/L, and 32,200 ng/L.  That farm is no longer producing milk for consumption and is not contributing to the milk supply. DACF, DEP, and CDC are investigating the potential sources of that farm’s PFAS contamination.
  • DACF conducted its third retail milk test of Maine milk in January 2021. One sampled processor had a detection of 43.2 ppt PFOS. DACF retested the sample, and the results were confirmed. DACF worked with the processor to review what farms had contributed to that sample. After a process of elimination, two dairy farms were identified as potential contributors. However, one farm had no history of sludge spreading, and testing it did not result in a PFOS detection level of concern. The second farm had no confirmed history of sludge application and had been tested in 2020 with no PFOS levels of concern detected. More research is required to resolve the source. This inconclusive determination demonstrates the complexity of PFOS and continued research and monitoring by DACF is needed.
  • A third farm was tested in fall 2020 and was found to have milk with a 620 ppt PFOS level. The farm immediately ceased producing milk for consumption. Due to the farm's intensive management efforts to provide clean feed to the animals and other on-farm changes, PFOS levels have sharply dropped, and the farm hopes to soon safely produce milk below the state's Action Threshold of 210 ppt and return to commercial production. Until that time, DACF is actively working with the farm to help it meet its goal.
  • 2019 Retail Milk and Farm Test Results (PDF)
  • 2020 Retail Milk and Farm Test Results (PDF)
  • 2021 Retail Milk and Farm Test Results (PDF)

What else is DACF doing?

  • DACF is currently working with the DEP to assess historical records of where licensed residuals may have been applied elsewhere on Maine farmland. Based on this detailed review, DACF will make careful decisions regarding potential next steps.
  • Note that with all historical records, gaps exist. More information about those farms identified must be collected to fully understand historic spreading activities, residual type, spreading location(s) and amount(s), crops or livestock produced, etc. to assess potential risk factors and identify appropriate risk management activities.

Is Maine working with other states?

  • DACF and its sister agencies are working with other states facing PFAS contamination to learn more about the emerging science and make well-informed decisions regarding appropriate testing and responses.

Where can I learn more?

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.