Mitchell Center researchers examine options for managing PFAS 

Researchers from the Senator George J. Mitchell Center for Sustainability Solutions at the University of Maine will help identify sources of and management strategies for per- and polyfluoroalkyl substances (PFAS).

In response to concerns raised by many different stakeholders, the interdisciplinary team of Mitchell Center scientists is gathering and documenting knowledge of where PFAS are in Maine and how they move through soil, water, wildlife and food. Researchers also are developing an understanding of how PFAS, also known as “forever chemicals,” end up in wastewater residuals organic materials and solids that are removed during wastewater treatment and how they are currently managed. They will then analyze and report on options for managing residuals while reducing the risks associated with PFAS and protecting Maine’s waters and lands. 

The project team also is meeting with public health advocates, representatives from the wastewater treatment industry and agriculture sector, and experts from state government to increase their understanding of concerns from the various stakeholders. The team is applying for federal funding to expand this work.

Dianne Kopec, Mitchell Center faculty fellow and adjunct professor in the UMaine Department of Wildlife, Fisheries and Conservation Biology, is leading the group. Other participants include Jean MacRae, an associate professor of environmental engineering; Caroline Noblet, associate professor in the School of Economics; Onur Apul, assistant professor and environmental engineer in the Department of Civil and Environmental Engineering; and John Peckenham, a research associate with the Mitchell Center. 

Researchers will look at the environmental, economic and social costs and benefits of currently available management options for wastewater residuals — including burying in landfills, incineration and application to agricultural fields — as well as other potential approaches. They also will conduct research to identify potential concerns of Maine residents regarding various management strategies. This information can help determine the social acceptability of different options and how to best communicate with citizens about issues involving PFAs. 

“We listen to the questions that stakeholders want answered,” Noblet says. “Listening to what people have to say, and to their concerns, feeds into the work from the beginning and through the whole process,” from forming questions to identifying and evaluating potential solutions.

The Maine Department of Environmental Protection (DEP) contacted Mitchell Center and UMaine leadership in spring 2020 asking for help in examining the complex environmental, economic, social and technical issues that need to be considered in addressing PFAS contamination.

Gov. Janet Mills created a PFAS Task Force in 2019 to study the extent of PFA contamination and its threats to public health and the environment. In a report issued in January 2020, the task force made recommendations that “reflect a commitment to determine where PFAS contaminants exist in Maine and put in place strategic responses to protect people from exposure.”

PFAS have been incorporated in a wide variety of consumer products, including waterproof and breathable rainwear, nonstick pans and takeout food containers, since at least the 1960s to repel water and oil. For decades, PFAS have also been used in firefighting foams to help suppress fires. While the benefits of PFAS are abundant and clear, the risks are only now becoming widely known. 

Production of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), two PFAS chemicals that have been used in nonstick cookware and a host of other products, was essentially phased out in the U.S. as of 2015. However, many PFAS chemicals are still being produced in the U.S. and around the world, and continue to be used in a wide range of consumer products. There is growing concern about the health effects of these chemicals for people, wildlife and the environment. They have been linked to harmful health effects in humans, including immune system disorders, thyroid hormone disruption and cancer. They also don’t break down readily and can biomagnify — or increase in concentration as they move through food webs. PFAS used decades ago are still circulating in the environment, in animals and plants, waterways and even in peoples’ bodies, which is why they’re often called “forever chemicals.”  

Maine officials first became aware of PFAS in groundwater near military bases, where firefighting foams had been used for training and fire suppression. In late 2016, more widespread PFAS contamination was found in groundwater, soils, field vegetation and milk from a Maine dairy farm — as well as in the farmers’ blood. Since then, DEP and the Department of Agriculture, Conservation and Forestry (DACF) have begun testing across the state and found elevated levels of PFAS in groundwater, farm soils, milk and freshwater fish near contaminated sites. 

The search for the cause of this contamination led to several potential sources, including wastewater residuals. Removing residuals during wastewater treatment has significantly improved water quality in rivers and other surface waters since the 1970s. Although these residuals contain valuable nutrients such as nitrogen and phosphorus, they can also contain harmful substances. Depending on the location, wastewater treatment plants may receive inputs from industrial sources as well as households and municipalities. 

Since at least the early 1980s, some wastewater residuals have been spread on agricultural fields to provide a low-cost nutrient source for farmers. This use is regulated under federal and state laws to protect soil and water quality. Residuals are treated to reduce the risks from pathogens and metals, which must be below regulatory standards to be used on agricultural fields. If they meet these standards, they are often referred to as biosolids. Until recently, PFAS were not monitored in wastewater residuals or biosolids. They are still not regulated at the federal level, but Maine has set screening levels for some PFAS chemicals.

As the evidence accumulated that biosolids were the likely source of PFAS contamination in agricultural soil and nearby groundwater, DEP increased its focus on how to manage the products of wastewater treatment. In 2019, they required that all licensees that land apply or process wastewater residuals test for PFAS and meet certain screening level concentrations. These licensees are also required to test for PFAS on an ongoing basis. DEP has also been testing for PFAS contamination in farm soils in fields where biosolids had been applied and nearby water wells. DACF has been testing for PFAS in milk from Maine dairy farms.

The Mitchell Center’s approach to addressing PFAS contamination and management in the state benefits from its broad range of expertise, which allows it to look at societal challenges from many different angles. The researchers for this project have expertise in environmental engineering, economics, risk perception, wastewater management, toxic contaminants in aquatic ecosystems and decision-making. 

Kopec is a wildlife ecologist whose work focuses on contaminants in fish, wildlife and ecological systems. Her experience includes leading an interdisciplinary team researching mercury in Maine’s Penobscot River. 

MacRae is an environmental microbiologist with expertise in wastewater treatment, solid waste management and chemical cycling in biological systems. She has worked with the Mitchell Center’s Materials Management team since its inception and recently completed a study of potential contaminants, including PFAS, in food waste recycling. 

Noblet is a behavioral environmental economist whose research focuses on how people use information, make decisions and perceive risks, especially in relation to natural resources management and the environment. She is working on the cost-benefit analysis of management options, as well as gauging people’s knowledge and views on the problem, its associated risks and ways to manage it. 

Apul has done research on incineration of PFAS-laden wastes, and will work with MacRae on assessing the technical feasibility of the management options being considered. His lab at UMaine will also investigate the potential for PFAS-contaminated liquids to move through soils and the clay liners that are often used to lessen the migration of pollutants from landfills to groundwater. 

Peckenham has worked for decades on wastewater and water pollution in Maine and has direct experience with contamination of groundwater from biosolids. He is the former director of the U.S. Geological Survey’s Maine Water Resources Research Institute (WRRI), which is headquartered at the Mitchell Center. 

Mitchell Center Director David Hart says he knows the importance of supporting partnerships in which interdisciplinary teams of researchers collaborate with diverse stakeholders to help address pressing sustainability challenges in Maine.

“We recognize that there are many different views on the challenges posed by PFAS contamination, as well as on the potential solutions,” he says. “There’s no easy fix to problems like this. But we’re committed to working with a wide range of stakeholders to understand the options for addressing PFAS problems, including the trade-offs and uncertainties of those options.” 

Contact: Ruth Hallsworth, 207.581.3196;