PFAS enter agricultural soils through a variety of means, including biosolids from municipal sewage and contaminated irrigation water, and from there they may be taken up by plants and then by animals, as well as into the drinking water of farmers. Since PFAS chemicals were widely used, they can still end up in wastewater treatment plants and other waste products from everyday household activities and industrial sources.
The application of residuals (which include industrial waste products and biosolids) on agricultural land was permitted and regulated by the Department of Environmental Protection (DEP) until LD 1911 was passed in May 2022, since these products contain nutrients which can enhance agricultural production. However, residuals may also contain PFAS, especially in the past. Since PFAS are persistent in the environment, the application of residuals decades ago can still impact PFAS levels in the soil today.
Beginning in 2019, the Maine Department of Agriculture, Conservation and Forestry (DACF) began testing Maine-produced fluid pasteurized milk to determine the level of one chemical, PFOS, in Maine’s milk supply, since residuals were often applied to dairy farms. Based on the survey results, DACF has high confidence in the safety of Maine-produced milk. However, several individual dairy farms have been found to have elevated levels of PFOS in milk, and are currently working with DACF to address contamination issues. Maine is one of the few states that has established screening levels to assess the level of PFAS contamination for products such as meat and milk (Maine does not yet have screening levels for any plant sources).
Maine DEP has expanded their testing of sites suspected to have PFAS/PFOS based on application of residuals. As testing expands, more and various types of farms are likely to become aware of PFAS contamination, and DACF, MFT, MOFGA and others are working together to be ready to support farms through research and direct assistance to identify alternative production and business strategies. Currently, the DEP has identified roughly 700 sites where residuals have been applied, located in nearly three dozen “Tier 1” towns throughout the state. These sites have been deemed to be at higher risk of contamination, and DEP has begun testing sites at the top of that list. The goal is to test all Tier 1 sites by 2023, and test all sites where residuals have been applied by 2025. More information about the state’s testing process and timeline can be found here.