Research

This study examines how PFAS present in agricultural soils become airborne during tillage events. Contaminants are often concentrated in fine soil particles, which can be lifted into the air as dust, potentially impacting environmental and human health. To understand this process, soil samples from multiple fields will be analyzed to determine how PFAS are distributed across different soil particle sizes. At one site, dust will be collected before, during, and after a field preparation to assess how much and how far contaminants travel. The results will help identify which soil components pose the highest risk for airborne transport and how their PFAS levels can be used to predict potential dust contamination. Findings from this study will provide valuable insights for farmers, researchers, and policymakers working to mitigate the risks of airborne soil contaminants in agricultural settings.

This project aims to investigate whether biochar can be used as a soil amendment to immobilize PFAS in the soil and reduce its bioaccumulation in the edible parts of vegetable crops, such as lettuce and tomatoes. The study will address several key questions: the optimal application rate of biochar in the soil, the frequency with which additional biochar should be applied after the initial amendment, and low-cost modification techniques to enhance biochar's ability to adsorb short-chain PFAS from the soil. This research will involve both laboratory and field studies. The findings will contribute to developing practical guidelines for farmers on the use of biochar in PFAS-affected soils.

Plant uptake from contaminated soils is a major way PFAS compounds enter our food systems. In the case of milk and meat, there is particular concern about uptake of perfluorooctane sulfonic acid (PFOS) by forage crops due to the prevalence and toxicity of PFOS. Being able to accurately predict how much PFOS moves from soil to plants to animals is critical for assessing risk and developing mitigation strategies, but one major factor complicating those predictions is that PFOS, like some other PFAS compounds, can be created through the transformation of "precursor" compounds. Concentrations of these PFOS precursors can vary widely from field to field and could be contributing to the high variability of plant PFOS uptake rates that have been observed. We will conduct paired greenhouse and field studies to assess whether PFOS precursor compounds in soil influence PFOS uptake rates from soil to grass, and to what extent.

One of the first steps in understanding how to manage PFAS on the farm is timely detection. Currently, this first step is burdensome for farms due to the slow turnaround time and high cost of analytical testing. Typically, it takes over a week to obtain test results at a cost of $200-$400 per sample, with multiple samples needed for each study. This proposed research will address this challenge by developing and demonstrating portable electrochemical sensors that can be used for rapid, on-site, and inexpensive testing. These user-friendly devices can be operated by farmers to obtain quick in-house results and determine the level of PFAS in different samples at different locations and times, hence obtaining a better understanding of the contamination issue for a timely response.

The research team seeks to develop strategies to reduce PFAS contamination in livestock animals, which will help protect agricultural integrity, public health, and animal welfare. This study will be conducted on ewes from an already awarded EPA grant, but adding additional samples to model the kinetics of PFAS bioaccumulation and depuration, as well as being able to sample during an entire lactation (beyond 81 days in milk). The first objective will focus on how PFAS moves through the animal's body during gestation, lactation, and depuration (cleaning) after being fed clean feed. The results will guide regulatory measures for PFAS contamination and its impact on animal products such as milk, meat, and eggs. The second objective examines the effects of feeding management practices during the weaning phase. The research will explore how early-life exposure to PFAS affects bioaccumulation of PFAS in animals and the potential for reducing contamination through clean milk replacers.

This project will examine how per- and polyfluoroalkyl substances (PFAS) on two biosolids-contaminated farms in Maine are transferred to poultry and eggs. We will consider exposures through direct consumption of contaminated soil, insects, earthworms, and airborne dust particles. We will monitor seasonal changes in eggs and test the effectiveness of different coop setup interventions (location changes, dust minimization, platforms, soil barriers) for minimizing PFAS exposure. Data will be used to provide advice for farmers for minimizing PFAS contamination in chickens and eggs and to develop soil screening values protective of public health.

Current PFAS cleanup methods are costly, energy-intensive, fail to fully remove PFAS, damage soil fertility, and create additional environmental waste. This project will use activated carbon coated on a plasma electrode to capture PFAS from soil. After capturing sufficient PFAS onto activated carbon, plasma will be activated to break down the PFAS molecules and refresh the activated carbon. By periodically activating plasma, this method not only destroys the PFAS but also refreshes the carbon's ability to capture PFAS. This approach is expected to deliver key benefits: 1) energy efficiency, by using non-thermal and low-power plasma reactions; 2) long-term effectiveness, by fully breaking down PFAS instead of just trapping them; 3) soil fertility and safety, by avoiding harmful soil disruption and generating nutritious nitrogen species; and 4) sustainability, by reducing waste by periodically refresh activated carbon.

Summary: Can sap from maple trees growing on land contaminated with “forever chemicals” (PFAS) be used to make food-safe maple syrup? To answer this question, researchers will work with Maine farmers, community members, and local groups to collaboratively choose ten contaminated sites from across the state, then collect soil and sap from 100 maple trees. Lab tests will measure how much PFAS moves from soil into sap and what happens to those chemicals during the syrup-making process. Filtration experiments will determine if it is possible to remove contamination from sap and/or syrup, and make a food-safe product. At the same time, social scientists will interview and survey farmers to learn about their experiences with maple sugaring and their knowledge of PFAS, and to identify what resources they would need to adopt or intensify PFAS-informed maple sugaring operations. The team will share findings in three open-access scientific papers, a farmer-focused guide, and an interactive website. Together, the results from this research will help determine if maple sugaring could be an effective way to make productive use of lands that are unsuitable for other types of agricultural because of previous contamination.

Summary: PFAS, or "forever chemicals", are widespread across Maine landscapes, including farms. Plants grown in contaminated soil can result in the uptake of PFAS into plants, from roots to flowers. Given the toxic effects of PFAS, animals that consume plants and plant products grown in contaminated landscapes can result in negative health repercussions. Bee pollinators, which provide pollination services to many flowering plants and crops, rely on pollen from flowers for their diets. Thus, the presence of PFAS across Maine landscapes may negatively impact the health and productivity of bee pollinators. However, no research has been done in Maine to investigate the consequences of PFAS for bees, limiting our understanding of how bees and agricultural producers may be affected in contaminated landscapes. To address this, we aim to evaluate the presence of PFAS in bee-collected pollen, identify flowering plants associated with higher PFAS concentrations, and characterize pollinator-specific responses to PFAS exposure.

Summary: Many farms in Maine have been adversely impacted by the discovery of per-and polyfluoroalkyl substances (PFAS) at elevated levels in soil, water and agricultural products. The main goal of the proposed is to investigate if the incorporation of locally available carbon-based biosorbents into heavily PFAS-contaminated agricultural fields will reduce PFAS uptake by feed grasses and corn plants. Results will also help to evaluate if the effectiveness of these high-carbon amendments support modified soil screening levels for safe food production. We will be conducting field trials with two Maine-relevant crops on two PFAS-impacted Maine farms at an operationally relevant scale, complemented with mathematical modeling studies that incorporate climate patterns and soil type, which will extend our ability to predict effectiveness of these high carbon particles at other sites. Results from this project will help Maine farms with PFAS contamination of all levels to continue to keep agricultural land productive.

Summary: The purpose of this research is to develop two methods to manage PFAS on contaminated farms. The first is a longer-term strategy to identify the operating conditions required to destroy PFAS in contaminated plant material using pyrolysis or hydrothermal treatment. Both methods involve high temperature and have been shown to destroy PFAS under certain conditions. PFAS destruction is needed to break the contamination cycle on farms, and reduce concentrations over time. The second method is to reduce the risk that PFAS will migrate off the site or into water. This method involves mixing the solid product of high temperature treatment of organics (char) with contaminated manure to prevent leaching of PFAS into water. Different experimental conditions will be tested to find the right char types and amounts to immobilize PFAS. The effects of UV light, fungi and freezing on immobilization will also be tested.

Summary: Per- and polyfluoroalkyl substances (PFAS) are man-made chemicals that persist in the environment and can contaminate water and land, affecting livestock and potentially human health. This project will study how PFAS exposure affects female reproduction in sheep. Ten ewes will be exposed to a combination of PFAS or remain unexposed, and researchers will monitor their hormone levels, ovarian function, and then the number and quality of embryos produced. Blood and reproductive tissues will be tested to confirm PFAS exposure and assess its effects at a molecular level. The results will help us understand how PFAS disrupts fertility and embryo development in livestock. This knowledge can guide farmers whose operations are affected by PFAS contamination, and may provide alternative strategies, such as in vivo embryo production, to maintain productivity while protecting animal and human health.

Summary: PFAS contamination in farmland has created serious challenges for Maine farmers, especially on fields where biosolids were applied in the past. Biochar, a carbon-rich soil amendment, has shown promise in reducing how much PFAS moves from soil into crops. However, results have been inconsistent, and farmers need clearer answers about when and how biochar is likely to work. This project will study how biochar affects PFAS uptake in different Maine soils. We will test how soil type, water conditions, and common farm management practices influence whether biochar reduces PFAS movement into forage crops that may be fed to livestock. The goal is to provide practical, science-based guidance to help farmers understand whether biochar can lower PFAS risk on their specific fields. Results will be shared through simple soil guidance tables and an easy-to-use online tool.

Summary: Some Maine farm soils contain PFAS (“forever chemicals”), but current soil tests measure the total amount of PFAS in soil without showing how much can actually be taken up by crops. This makes it difficult for farmers and regulators to understand whether a given soil concentration poses a real risk to food safety. This project will test different soil extraction methods to determine which ones best estimate the portion of PFAS that plants can access during a growing season. We will grow lettuce in greenhouse pots using four Maine soils and compare PFAS levels in the plants to PFAS measured in the soils using different testing approaches. We will also study how soil amendments, such as manure and high-carbon ash, affect PFAS mobility and plant uptake. The results will help improve how soil PFAS test results are interpreted and provide more practical, science-based guidance for managing PFAS in Maine agriculture

Summary: Perfluorooctane sulfonic acid (PFOS) and perfluorodecanoic acid (PFDA) are PFAS chemicals that move from contaminated soil to hay to beef cattle, creating potential risks for food safety. A model has been developed to predict the daily build-up of PFAS in cattle from feed and water. However, PFDA predictions are uncertain because a key model input called the volume of distribution (Vd), which links the amount of a PFAS cattle consume to how much is in their blood and muscle, has never been directly measured for PFDA in cattle. This project will collect blood samples from cattle that have eaten contaminated hay for several months, and samples of their hay and water, to measure how PFAS moves into cattle. These data will be used to calculate a PFDA-specific Vd, confirm the current PFOS Vd, and provide improved predictions to help farmers make informed decisions for reducing PFAS contamination in beef. 

Summary: PFAS have been found in the eggs of chickens raised on land where biosolids were historically spread, resulting in contaminated soil. In some cases, these levels have been high enough to raise public health concerns. Recently, a maximum allowable level for one PFAS in particular, perfluorooctane sulfonic acid (PFOS), in commercial eggs was established in Maine. However, it is still not well understood how PFAS move from soil through the environment and into chickens and eggs, making it difficult to offer guidance for farmers and homesteaders. This study will follow two groups of chickens from summer into early fall, one with exposure to PFAS-contaminated soil and one without. Throughout this time, grasses, insects, earthworms, and feed accessible to chickens will be sampled, along with their eggs, providing the necessary data to understand the different ways hens are exposed to PFAS and identify practical strategies to reduce PFAS in poultry products.