L. Voices of the PFAS issue in Maine

This session is approved for training contact hours (TCH) through Maine’s Wastewater Operator Certification Program. Sign-up sheets will be located in the session room.

Afternoon Session – 1:30PM-4:00PM
Cumberland Room (1st floor)

Session Co-Chairs

Per- and polyfluoroalkyl substances (PFAS) contamination was reported widely throughout Maine and the United States in the last several years. Maine has taken an active role in efforts to address PFAS, often leading the nation in mandates, testing efforts and support to those impacted. This session aims to present results and perspectives about the current understanding of PFAS contamination and mitigation strategies with an extended focus on the wide variety of Maine residents impacted by, and addressing, this issue.

Session Overview

Session Abstracts

Presenters are indicated in bold font.

Uptake of PFOS by Vegetables – Observations from Field Studies on Farms and Home Gardens with PFOS Contaminated Soils.

A pdf of this presentation is available. Please contact Andy Smith with any questions.

Andrew E. Smith, Thomas Simone1, Duncan Pfaehler2, Sara Gillooly1
1. Maine Center for Disease Control and Prevention, Augusta, ME
2. Maine Department of Agriculture Conservation Forestry

The testing of Maine farmland with a history of land application of biosolids and other residuals has identified soils with elevated levels per- and polyfluoroalkyl substances (PFAS). Some PFAS contaminated farmland has been re-purposed for vegetable farming. These sites have provided opportunities for testing vegetables to assess the uptake of PFAS into edible plant tissue. There is currently little published data on the uptake of PFAS by vegetables grown in field settings. This presentation will discuss methods and results from sampling a variety of vegetables for the presence of PFAS with a focus on perfluorooctane sulfonate (PFOS). Crops tested include lettuce, spinach, arugula, swiss chard, kale, bok choy, asparagus, rhubarb, carrots, corn, squash, green beans, potatoes, and tomatoes. Plant transfer factors for PFOS (the ratio of PFOS in the plant tissue on a wet weight basis to PFOS in soil on a dry weight basis) varied considerably among tested vegetables and were generally less than 0.03. The PFOS transfer factors were similar to or lower than published findings from potted plant, greenhouse, and limited field studies. Lettuce had the greatest propensity to take up PFOS from soil, followed by spinach, arugula, swiss chard and carrots. There was minimal uptake of PFOS in potato tubers and squash. PFOS was not measurable in plant tissue of corn kernels, green beans, tomatoes, asparagus, and rhubarb despite relatively high levels in the soil levels. These data, once replicated, may provide information farmers can use in selecting crops they will grow on PFOS contaminated soils.

Uptake Takeaways: Physiological and Chemical Drivers of PFAS Uptake in Crops

A pdf of this presentation is available. Please contact Alex Scearce with any questions.

Alex Scearce, Rachel Schattman, Jean MacRae, Caleb Goossen, Yongjiang Zhang, Ellen Mallory
University of Maine

Widespread PFAS contamination in agricultural areas is attributed to the application of sludge from wastewater treatment plants (WWTP) in which PFAS can be highly concentrated. This creates a pathway for these contaminants to enter the food chain, and by extension cause human health concerns. In some cases, concerns about contaminated farm products have led to farm closures. One limitation of current PFAS regulation is the large variation in potential uptake across crop species. A review of the literature suggests that some food crops are likely to accumulate PFAS in different “plant compartments” (i.e., roots, shoots, leaves, etc.). Additionally, some crop species will take PFAS up from soil and water more than others. Currently, state policy in Maine is limited to beef and milk. However, there is more to be explored related to how different crop species take up PFAS, and in what plant parts. This information will play a crucial role in shaping our understanding of crops that are and are not viable for farm production and safe for human consumption. In this presentation, we will share the current understanding of uptake in various commercial plant species and plant parts, and the physiological and chemical drivers of variation in uptake such as transport pathways, transpiration, and chain length.

Afternoon Break

Messages that help consumers of Maine Food navigate PFAS information

Caroline Noblet, Erin Percival Carter, Qiujie “Angie” Zheng
University of Maine

Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals used in consumer products for decades which recent research demonstrates present a risk to human, animal, and environmental health. PFAS contamination of water and soil in agricultural areas, and of food produced in these areas, is a growing area of concern but few states regularly test for contamination. Maine is a key exception and has been a leader in both testing for and communicating about PFAS. However, being a ‘first mover’ in this space presents a unique challenge, whereby Maine must balance the duty to educate the public about the risk and magnitude of contamination with the risk that doing so could engender negative perceptions about food produced in the state. The impact of testing for, and communicating about, PFAS on consumers’ perceptions of the relative safety of food produced in Maine is unknown. In this study, we used contemporary behavioral science to develop and test the effectiveness of messaging strategies designed to mitigate potential negative effects of Maine’s transparent PFAS strategy. We also examine effects of different message framings on consumers’ likelihood to request and preferences for additional information, assignment of blame for contamination, and beliefs about how future efforts to address PFAS testing and mitigation should be funded. Overall, the results of this study provide important insights for those seeking to educate the public about the risks associated with PFAS in a region while minimizing undue damage to perceptions of all food produced in that region.

Estimated Greenhouse Gas Emissions and Risk Reduction from PFAS Treatment of Maine Drinking Water

A pdf of this presentation is available. Please contact Benjamin McAlexander with any questions.

Benjamin L. McAlexander1, Onur G. Apul2, Mitchell R. Olson1, Jean MacRae2
1. Trihydro
2. University of Maine Civil and Environmental Engineering Department

The State of Maine is currently operating under an interim drinking water standard of 0.020 ug/L for the sum of six individual PFAS compounds. In addition, state law requires that the Department of Health and Human Services adopt a maximum contaminant level (MCL) for PFAS contamination in drinking water by June 1, 2024. Treating drinking water to the interim standard, and possibly to lower levels established by a future MCL, will likely rely on the established method of PFAS sorption to granular activated carbon until other technologies are further developed. The discussion of appropriate PFAS drinking water standards with this presumptive technology has largely focused on risk reduction and the cost of treatment, while largely ignoring indirect environmental effects. We conducted an evaluation of greenhouse gas (GHG) emissions associated with water treatment for Maine-specific scenarios using this energy-intensive treatment media to try to fill this gap in the discussion. We found that GHG emissions for water treatment, on a per-user basis, will likely be substantial (e.g., 1.0 to 2.7 metric tons CO2 eq, or 6.7% to 18% of US per capita emissions) for the current interim drinking water standard. Lower target water concentrations, while achieving greater risk reduction, would also mean even greater emissions. We use this information to discuss implications for policymaking, including approaches for establishing the MCL, and for coordination across the state once the MCL is established. This evaluation advances GHG emissions as an important concept to the PFAS standard.