Session 7 – PFAS and Emerging Contaminants

This session has been approved for 4 Four Training Contact Hours (2 morning, 2 afternoon) through the Maine CDC Drinking Water Program. Participants interested in applying should email umgmc@maine.edu.

This session has been approved for 4 Training Contact Hours (2 morning, 2 afternoon) through Maine’s Wastewater Operator Certification Program. Participants interested in applying should email umgmc@maine.edu

Thursday, April 1

  • Part A: 10:00AM-12:00PM
  • Part B: 1:30PM-3:30PM

Co-Chairs: Charlie Culbertson, U.S. Geological Survey; Jason Sorenson, U.S. Geological Survey

Per- and Polyfluoroalkyl Substances include a wide range of compounds that have been used in a wide range of domestic and industrial applications since the 1950. They are very persistent in the environment, highly mobile, bioaccumulate and have been linked to several negative health outcomes such as immunotoxicity and cancer. Other contaminants that are poorly understood include compounds associated with wastewater effluent such as pharmaceuticals and personal healthcare products (PPHCPs) and endocrine disruptors. Microplastics and nanoparticles are examples of other two other groups of ‘emerging’ contaminants. These substances represent a large and diverse group of pollutants that urgently require more work to refine analytical methods, quantify sources, develop transport models, and a better understanding of human and ecological health risk and exposure pathways.

Session Overview

Part A – 10:00AM-12:00PM

Part B – 1:30PM-3:30PM

Additional Presentation:

Presentations

10:00AM-10:20AM
An Overview of the State of PFAS Science and Ongoing Research Efforts at the U.S. Geological Survey Cape Cod Field Laboratory

Andrea K. Tokranov, Denis R. LeBlanc
U.S. Geological Survey, Northborough, MA

Per- and polyfluoroalkyl substances (PFAS) are persistent anthropogenic contaminants commonly found in the environment owing to their widespread use in industry, consumer products, and aqueous film-forming foams (AFFFs). Adverse impacts on human and wildlife health associated with PFAS exposure have prompted a national response to protect drinking-water supplies. This talk will provide an overview of the state of science in the rapidly evolving landscape of PFAS research, with a focus on PFAS fate and transport. In addition, ongoing research on PFAS mobility and precursor persistence at the U.S. Geological Survey field laboratory on Cape Cod will be presented. The sand and gravel sole-source aquifer on Cape Cod provides a unique opportunity to study mobility and transformation of PFAS because of the long history of research on the Cape’s hydrologic system.  PFAS-containing AFFFs were used on Cape Cod during fire-training exercises between 1970 and 1985, creating a plume of groundwater contamination that discharges to the upgradient end of a lake (Ashumet Pond). Lake water is recharged to the aquifer across the surface-water/groundwater boundary on the downgradient end of the lake. The effects of groundwater/surface-water interaction on PFAS transport and the fate of perfluoroalkyl acid precursors will be discussed, in addition to an overview of other ongoing research on Cape Cod.

10:20AM-10:40AM
Dealing with the PFAS Legacy in Maine

Norman R. Labbe, PE
Former Superintendent, Kennebunk, Kennebunkport & Wells Water District

The purpose of this presentation is to share the experience of a public water system impacted by PFAS and to describe the current status of the PFAS contamination issue in Maine.

Per- and Polyfluoroalkyl Substances (PFAS) are a family of very resilient, man-made organic chemicals that have been used extensively for a variety of purposes; including but not limited to fire suppression, water proofing and stain repellency. PFAS has an estimated half-life in humans of between three to six years. They are also very miscible in water and can also spread airborne. In the environment they don’t readily break down; as such they have been referred to as “forever chemicals”. The KK&W Water District found PFAS in one of its water supplies and has since mitigated the issue, with the assistance of Maine’s Drinking Water Program.

The larger concern however relates to the fact that this PFAS contamination did not come from a known contaminated site but from the approved (permitted) spreading of municipal and industrial residuals on nearby farmland; a common practice throughout the region. For this reason, the implications of PFAS contamination in Maine stretch far beyond that of drinking water.

As a result of increasing local, regional and national concern, in March, 2019 Governor Mills created Maine’s PFAS Task Force, on which the presenter was a member. Its final report outlines Maine’s next steps toward addressing the PFAS issue, which will be described in this presentation.

10:40AM-11:00AM
The Challenges of Modeling PFAS Transport from Soil to Groundwater at Legacy Sites

Gail Lipfert, Troy Smith, Chris Evans, Sean Dougherty
Maine Department of Environmental Protection

The fate and transport of PFAS chemicals in the environment is poorly understood. The Maine Department of Environmental Protection used soil and groundwater PFAS concentrations from several sites to model PFAS transport through the vadose zone and along the groundwater flowpath.

We used SEVIEW, a software that incorporates SESOIL, which models the transport of contaminants through the vadose zone to the water table, and AT123D, which models contaminant transport along the groundwater flowpath.

Preliminary results indicate that adsorption to soil is the primary controller of the movement of PFAS through the soil to groundwater, hence, the amount of organic carbon in the soils (a rarely measured parameter) has a strong influence on rate of transport. The depth to groundwater strongly affects the arrival time of PFAS to the groundwater. At sites where the depth to groundwater was more than 6 meters, the arrival times were unrealistically long, not getting to some wells for over 900 years. These results are inconsistent with measured concentrations and more work will need to be done to improve models of long-distance transport of PFAS. At other locations where the vadose zone transport distances are shorter, the modeled groundwater concentrations are generally comparable to measured concentrations.

Our primary conclusion is that modeling current soil and groundwater PFAS data with SEVIEW is more consistent with measured concentrations under simple scenarios and well-established conditions, but not consistent with measured concentrations when the current or initial conditions are poorly known and long transport distances are involved.

11:00AM-11:20AM
What contaminants are in our food waste, and can it be safely recycled to circularize the food system?

Jean D. MacRae
University of Maine Department of Civil and Environmental Engineering

A video of this presentation is available

A circular food system would reduce the energy intensity of our agricultural system and reduce our reliance on dwindling phosphorus reserves. Diverting food waste from landfill also reduces methane and leachate production, and can stimulate new economic opportunities producing heat, electricity and useful soil conditioners (compost and digestate) from food scraps. While these efforts are positive, we need to be careful to ensure the new pathways don’t introduce new contamination risks into our food system. We measured physical, chemical and biological contaminants in source-separated food waste samples from three states and six source types. We found that heavy metals were rarely detected and when they were, they were below the most stringent global standards for application to soils, so this was not an issue of concern. Halogenated organics were measured using the “bulk” EOX method, which has a high detection limit, but encompasses all of these potentially bioaccumulative pollutants. They were detected in 14% of our samples. A subset of samples were also tested for PFAS. Over half of these contained PFBA, despite removal of visible physical contaminants prior to processing the food waste. The presence of these chemicals in compost or digestate could represent a risk to the system. Another finding of concern was the near-universal detection of tetracycline and penicillin resistance genes (ARGs) in the samples. Most ARGs are located on mobile genetic elements that can be transferred among microbes, and their prevalence in the environment has increased with the use of antibiotics in agriculture, so they are viewed as a risk to infection control therapies. Assessing the risk of these contaminants to a circular food system depends on their fate during treatment, and additional sources during preprocessing.

1:30PM-1:50PM
The degradation of A/B AFFF in real time at a small site in Maine

Louise Roy
Bureau of Remediation & Waste Management, Maine Department of Environmental Protection, Augusta, ME

A video of this presentation is available

Nationally, much of the focus of PFAS research is directed towards large sites, such as military bases, landfills, and firefighter training areas. However, small sites with a single event can provide insight into the degradation process of PFAS in a natural environment and the TOP Assay’s ability to predict precursor transformations.

A vehicle fire in February of 2019 provided us the opportunity to study the movement and degradation of an A/B AFFF after a single introduction into the environment. The foam and petroleum products from the event made their way to a well on the property, which we were able to sample with some frequency. Maine DEP installed two large carbon filters to protect the home’s drinking water. Results showed that the TOP Assay appears to be a good indicator of which products will occur during the natural degradation of 6:2 FTS. In this presentation, I show a slow progression of precursors to products using stiff diagrams. This presentation will give some background on the TOP assay and will touch on the treatment’s ability to detect compounds outside of the normal suite of 24 analytes.

1:50PM-2:10PM
PFAS? Yes, PFAS – a serious problem in need of a sustainable solution

Dianne Kopec, Onur Apul, Jean MacRae, Caroline Noblet, John Peckenham

Senator George J. Mitchell Center for Sustainability Solutions, University of Maine, Orono, ME

A video of this presentation is available

Up until the last 20 years, PFAS, fluorinated organic compounds developed in the 1930s and used since the early 1960s in consumer products from non-stick cookware (e.g., Teflon) and breathable rainwear (e.g., Gore-Tex) to molded-fiber take-out containers (yes, those which replaced Styrofoam), were not recognized by EPA as a contaminant problem. Today PFAS chemicals are described as one of the most consequential environmental crises in the US – PFAS are ubiquitous, toxic, and persistent in humans and the broader environment. The persistence of PFAS, combined with human exposure, led to PFAS entering our waste stream and accumulating in the sludge-like biosolids left over from treatment of residential and industrial wastewater. Since the 1980s biosolids have been spread on farm fields, a source of nutrients and amendments aimed at improving soil quality. Here in Maine, the discovery in late 2016 of PFAS contamination in cow’s milk and drinking water wells from a dairy farm in Arundel, and in 2020 at another dairy farm in Fairfield, was attributed to past agricultural spreading of biosolids and led Maine DEP (Department of Environmental Protection) to reevaluate that practice and look for alternatives. In response to this need our interdisciplinary team of researchers from UMaine‘s Mitchell Center will work with stakeholders from Maine DEP, the wastewater industry, public health advocates, and agricultural interests to evaluate sustainable management options for PFAS-contaminated biosolids. We will examine the environmental effects, the chemical engineering constraints and opportunities, the public perception of risk from the different options and the economic costs associated with the alternatives to agricultural spreading of PFAS-contaminated biosolids.

2:10PM-2:30PM
Thermal Regeneration of Spent Granular Activated Carbon Presents an Opportunity to Break the Forever PFAS Cycle

Busra Sonmez Baghirzade1, Yi Zhang2, James Reuther3 Navid B. Saleh4, Arjun K. Venkatesan2, Onur G. Apul5

1 Department of Civil and Environmental Engineering, University of Massachusetts Lowell, Lowell, MA
2 New York State Center for Clean Water Technology, Stony Brook University, Stony Brook, NY
3Department of Chemistry, University of Massachusetts Lowell, Lowell, MA
4Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, Austin, TX
5Department of Civil and Environmental Engineering, University of Maine, Orono, ME

A video of this presentation is available

Extensive use of per- and poly-fluoroalkyl substances (PFAS) has caused their ubiquitous presence in natural waters. One of the standard practices for PFAS removal from water is adsorption onto granular activated carbon (GAC); however, this approach generates a new waste stream i.e., PFAS-laden GAC. Considering the recalcitrance of PFAS molecules in the environment, inadequate disposal (e.g., landfill or incineration) of PFAS-laden GAC may let PFAS back into the aquatic cycle. Therefore, developing approaches for PFAS-laden GAC management present unique opportunities to break its forever circulation within the aqueous environment. This comprehensive review evaluates the last two decades of research on conventional thermal regeneration of GAC and critically analyzes and summarizes the literature on regeneration of PFAS-laden GACs. Optimized thermal regeneration of PFAS-laden GACs may provide an opportunity to employ existing regeneration infrastructure to mineralize the adsorbed PFAS and recover the spent GAC. The specific objectives of this review are (i) to investigate the role of physicochemical properties of PFAS on thermal regeneration, (ii) to assess the changes in regeneration yield as well as GAC physical and chemical structure upon thermal regeneration, and (iii) to critically discuss regeneration parameters controlling the process. This literature review on engineered regeneration process illustrates significant promise of this approach that can break the endless environmental cycle of these forever chemicals, while preserving the desired physicochemical properties of the valuable GAC adsorbent.

2:30PM-2:50PM
Antimicrobial Agent Cetylpyridinium Chloride Inhibits Immune Mast Cell Function

Bright Obeng*, Bailey E. West, Marissa S. Kinney, Christian M. Potts, Suraj Sangroula, Sasha R. Weller, Alan Y. Baez, Julie A. Gosse
Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME

Cetylpyridinium chloride (CPC) is a positively charged antimicrobial used in consumer products such as mouthwashes at concentrations up to 3 millimolar, thus exposing humans to high concentrations. There is minimal information on eukaryotic toxicology of CPC; hence, there is urgent need for information since humans and wildlife are being exposed to CPC. Mast cells, ubiquitous through the body, sit at the hub of numerous physiological processes and diseases. We have demonstrated that CPC potently inhibits functioning of RBL-2H3 mast cells, including their ability to degranulate, which is the release of bioactive substances including histamine. Degranulation inhibition occurs at non-cytotoxic CPC doses as low as 1 micromolar, ~1000-fold lower than the concentrations found in consumer products. We have investigated the molecular mechanisms underlying the inhibition of mast cell degranulation by CPC. We have shown that CPC inhibits store-operated calcium entry (SOCE), a core mediator of the degranulation pathway. Using the genetically encoded voltage indicator ArcLight A242 and confocal microscopy, we have shown that CPC does not interfere with key contributors of SOCE, plasma membrane potential and cytosolic pH, in mast cells. The negatively charged plasma membrane lipid phosphatidylinositol 4,5 bisphosphate (PIP2) is also a key player in SOCE. CPC displaces the PIP2-binding protein, MARCKS, from PIP2, suggesting a PIP2-mediated mechanism for CPC inhibition of SOCE.  This research provides biochemical mechanisms underlying the effects of CPC on immune signaling and allow prediction of CPC effects on cell disparate cell types that share similar signaling elements.

PFAS Treatment Technologies and the Role of Fractionation

Baxter Miatke, Corey Theriault, John Anderson
Arcadis U.S.

A video of this presentation is available for viewing on the conference platform.

Arcadis has experience with several different PFAS treatment technologies and their uses in the industry. This presentation will provide an overview of current treatment technologies and focus on how fractionation ties into the current treatment train. Arcadis designed and built a bench-scale fractionation column, first of its kind known in the U.S., to test PFAS removal efficiency of industrial wastewater. The Arcadis Treatability Lab optimized the fractionation column for PFAS treatment. This presentation will use this case study to show why fractionation works for PFAS treatment specifically. This presentation will provide field-proven demonstrations of the technology that shows practical adaptation of fractionation treatment of PFAS impacted wastewater in the U.S.