Per- and Polyfluoroalkyl Substances (PFAS)

Public Law 2021, Chapter 478, An Act To Investigate PFAS Substance Contamination of Land and Groundwater became effective on October 18, 2021. This law requires the DEP to develop and implement a program to evaluate soil and groundwater for PFAS at locations licensed to land apply sludge or septage prior to 2019.

DEP began its initial statewide evaluation into the presence of PFAS in soil and groundwater at licensed sludge/septage land application sites in November 2021. Sites were identified based on gathering, reviewing, and evaluating decades of licensing information. Each site typically includes multiple fields (i.e., agricultural land, pasture, or other land) and may also cross district, town, and county boundaries. Some sites may have different owners than when a license was first issued, requiring DEP’s evaluation to include identifying land use changes and practices. As an example, a site that was an active farm back in 1986 may now include several small farms, a subdivision, and a school. Moreover, some sites may have been used by multiple generators (different sources of sludge or septage), which land applied in the same location.

The initial evaluation process for each site includes sampling of soils at licensed land application sites as well as nearby private drinking water wells (groundwater) determined to be at risk for PFAS impacts from these sites. Initial evaluation sampling locations are developed by DEP scientists based on several site-specific factors including land application records, hydrogeology, and proximity to licensed sites.

Once DEP staff have completed the initial evaluation, DEP scientists review the data and make a determination as to whether an expanded investigation is necessary, referred to as a “step-out investigation”. Where groundwater levels exceed Maine’s interim drinking water standard surrounding a land application site, the radius of investigation may be expanded. Not all sites will require step-out sampling. Step-out sampling may take a few extra weeks or in some cases may take years for larger sites that have many fields contributing to potential contamination.

In locations where it is determined that private drinking water wells exceed Maine’s interim drinking water standard for the sum of 6 PFAS (PFOA, PFOS, PFNA, PFHxS, PFHpA, and PFDA), and contamination is likely due to the land application of sludge or septage, DEP will work with homeowners to ensure that they have clean water to drink. In these circumstances, DEP will provide homeowners with bottled water until a filtration system can be installed and determined to be effective.

Preliminary Private Drinking Water Well Information by Town as of April 21, 2023
To ensure that the system is effective, DEP will sample the system 1-3 months after installation. If the system is working effectively, bottled water will no longer be provided, and instead a schedule will be developed for the monitoring and maintenance of the installed filtration system.

At active farms, sampling of PFAS in agricultural products, irrigation water, and at specific soil locations is coordinated through the Maine Department of Agriculture, Conservation and Forestry as the needs for farmers are different than other types of landowners and homeowners.

Communities with Tier I and II Sites

The Tier list will continue to be under development as sites may shift from Tier to Tier.  This is because more information is expected to be gained as the investigation continues.

Inquiries about the soil and groundwater evaluation should be directed to David Madore, Deputy Commissioner and Communications Director, 207-287-5842. You can also contact the Department directly by e-mail at: pfas.dep@maine.gov

Septage land application sites are being evaluated separately than sludge. This is because septage application sites are licensed and managed differently than sludge, and several are currently active. Evaluation of these sites began Summer 2022.

Initial investigations into the septage land application sites began in the communities identified in the table below. Additional counties and towns will be added as more contracts are put into place. Similar to the sludge site investigation, the initial evaluation process for each site includes sampling of soils at septage land application sites, as well as nearby private drinking water wells (groundwater) for PFAS.

Inquiries should be directed to David Madore, Deputy Commissioner and Communications Director, David.Madore@maine.gov, 207-287-5842. You can also contact the Department directly by e-mail at: pfas.dep@maine.gov

DEP expects to complete the initial evaluation of Tier I sites and begin initial evaluations of Tier II sites in August 2022. This means that DEP will be able to shift the focus to the evaluation of Tier II sites while simultaneously conducting step-out sampling in Tier I sites, as warranted, as well as continued filtration system monitoring.

This shift forward does not mean that the DEP will never return to a Tier I location. It just means the initial evaluation is complete. In some Tier I locations, the DEP will continue to sample when a step-out investigation is needed.

Evaluation of septage sites began during the summer of 2022. As of early August sampling has begun in some but not all communities identified under Evaluation of Licensed Septage Sites. Additional information will be provided soon.

On September 1, 2021, the Department sent a letter to solid waste landfills that manage leachate (contaminated liquid that drains from a landfill) requiring that leachate be tested for PFAS, beginning October 18, 2021, as required by Public Law 2021, Chapter 478. Five rounds of sampling are required in total: each round collected during the fall and spring beginning fall 2021 and ending fall 2023. Data collected must be sent to the Department for review and evaluation. In 2024 DEP will present this data to the legislature along with recommendations.

Landfill Leachate Sampling Results for 6 PFAS (PFOA, PFOS, PFNA, PFHxS, PFHpA, and PFDA):

Fall/Winter 2021

Spring/Summer 2022

Fall/Winter 2022

Spring/Summer 2023: Data not available yet

Fall/Winter 2023: Data not available yet

PFAS contamination is also being investigated at remediation (or cleanup) sites in Maine. Investigation of PFAS at these sites typically occurs to assess whether a hazardous substance is present at a concentration that poses a risk to public health or the environment. In these cases, the DEP works toward removing or mitigating those identified threats.

The Maine legislature changed the definition of hazardous substance under the state’s uncontrolled sites law in 2021 to include PFAS under 38 MRS §1362 (1)(H). This change clarifies that a hazardous substance means any substance that is listed as a hazardous substance or meets the criteria for a pollutant or contaminant under the United States Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). At this time, PFAS is managed as a pollutant or contaminant under CERCLA as PFAS compounds are not yet designated as a CERCLA hazardous substance. This may change as the EPA implements it’s 2021 PFAS Strategic Roadmap.

Specific remediation programs at DEP that have investigated PFAS contaminated sites include the Uncontrolled Sites Program, Municipal Landfill Closure and Remediation, VRAP, and Brownfields programs. In addition, several Federal facilities and Superfund sites are also undergoing investigation and remediation of PFAS.

At this time, there are several widely recognized and effective technologies for the removal of PFAS from water. The most common techniques include adsorption (the adhesion of atoms, ions, or molecules from a gas, liquid, or dissolved solid to a surface) using media such as Granular Activated Carbon (GAC) and Ion Exchange (IX), or Reverse Osmosis (RO). Information about each of these technologies is available at the USEPA website. In addition, the USEPA has more information about novel technologies for PFAS treatment through its Drinking Water Treatability Database.

Maine residents with private drinking water wells exceeding Maine’s interim drinking water standard, as identified through the state’s soil and groundwater investigation, are provided with filtration systems to ensure their drinking water is clean and safe. Typically, Maine DEP and its consultants install GAC systems, but in some circumstances an Ion Exchange or Reverse Osmosis system may be determined to be more economical and is utilized. GAC is an effective method of treatment in the vast majority of cases and has been shown to be effective through ongoing post-installation sampling at Maine residences.

One consideration of treating PFAS in drinking water is that filters collect PFAS resulting in residuals or waste materials with concentrated levels of PFAS. These residuals or waste materials must be properly disposed of or destroyed.

In 2019, the USEPA issued a Technical Brief on the incineration of PFAS as a means to manage waste streams. This technical brief outlined the state of the science in 2019 and did not clearly endorse incineration as a safe or preferred method for managing PFAS waste streams. This is because some research has indicated that PFAS may break down into components that may be other forms of problem PFAS chains. In April 2022, the Pentagon halted the practice of incineration at Department of Defense sites.

In Spring 2020, the USEPA established the PFAS Innovative Treatment Team (PITT), a team of interdisciplinary staff, to evaluate options for PFAS treatment and destruction. More detail about their work is available at the above USEPA website specifically pertaining to these four technology types: super critical water oxidation (SCWO), pyrolysis and gasification, mechanochemical degradation, and electrochemical oxidation.

In August 2020, the USEPA Office of Innovation issued a PFAS Challenge to the nation for innovative ways to destroy PFAS. Applicants were asked to develop destruction technologies to achieve 99% destruction of PFAS in Aqueous Film Forming Foam (AFFF) formulations (i.e., fire suppressant foam). Winners of the challenge submitted proposals for the following technologies: Hydrothermal processing, UV light, and continuous flow liquid-phase plasma discharge.

Later the same year, USEPA’s Office of Research and Development (ORD) presented information to Region 1 States and Tribes on PFAS Treatment and Destruction Technologies, and at the end of the year released the Interim Guidance on the Destruction and Disposal of Perfluoroalkyl and Polyfluoroalkyl Substances and Materials Containing Perfluoroalkyl and Polyfluoroalkyl Substances. The document provided information on state of science and associated uncertainties for current commercially available disposal or destruction technologies (as of late 2020).

In June 2022, USEPA established a PFAS Thermal Treatment Database with information about the following methods of thermal treatment for PFAS:

The state of science is still evolving and is expected to change over the next several years as more and more entities develop and engineer new methods for treatment and destruction. At this time however, most of the existing technologies are in pilot phase only and have not been developed for larger scale use. This means that traditional disposal methods, such as landfilling, continue to be the current mechanism for PFAS management.

Multiple State agencies including Maine’s DEP, Department of Agriculture, Conservation and Forestry (DACF), and Department of Inland Fisheries and Wildlife (DIF&W), are working together to monitor and evaluate opportunities to use new technologies for treatment, concentration, and destruction of PFAS. This includes addressing concerns about sludge, septage, leachate, water, soil, milk, animal wastes, and other agricultural products. Because technologies are still evolving, matching the right technology to the right location and set of circumstances, while also ensuring that funding is available to support these new technologies, is challenging. Maine is struggling to find readily available technologies that will resolve issues surrounding statewide treatment and destruction needs quickly and within reasonable costs. At this time, the above state agencies are coordinating efforts to research and identify technologies suitable for treating multiple waste streams as identified below.