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?

  • In 2016, PFAS chemicals were found to be present at unsafe levels in the milk of a Maine dairy farm that had historically applied biosolids and papermill residuals to its fields. In 2017, the Maine Center for Disease Control & Prevention created an Action Threshold for milk to determine when milk is considered adulterated. That Action Threshold is 210 ng/L.
  • 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, DACF has high confidence in the safety of Maine-produced milk.

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?



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