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This SERDP and ESTCP webinar focuses on DoD-funded research to address challenges regarding per- and polyfluoroalkyl substances (PFAS) analysis. Specifically, investigators will provide an overview of PFAS analytical methodologies, progress towards improving PFAS analytical methods, and factors that impact PFAS stratification in water columns that may result in artifacts in measured PFAS concentrations.

“Overview of PFAS Analytical Challenges and Opportunities” by Janice L. Willey

Over the past few years, the analysis of PFAS has been evolving. During this period, PFAS analyses needs have grown from evaluation a few PFAS in drinking water to evaluation an extensive list of PFAS in almost every media imaginable. This presentation will highlight some of the more significant analytical challenges we have faced along the way and provide a brief summary of some of the efforts currently underway to address them.

"Developing Analytical Methods for Comprehensive Profiling of PFAS in AFFF Impacted Environmental Matrices" by Dr. Jinxia Liu (SERDP Project ER18-1157) 

This presentation focuses on a SERDP project to develop improved analytical methods for PFAS originating from aqueous film-forming foams (AFFF). Except for drinking water (Environmental Protection Agency [EPA] Method 537), standardized procedures for PFAS analysis in environmental matrices are not readily available. The suite of legacy PFAS routinely analyzed in various laboratories does not capture all the dominant anionic, cationic, and zwitterionic PFAS occurring at AFFF-impacted sites. In this project, we will provide results from extensive optimization and validation experiments to allow establishing standardized methods. We will create guidance to end-users regarding choices of quantitation approaches and associated potential limitations. This presentation will highlight the latest progress made towards improving analytical methods with a focus on the following: (1) compound-specific PFAS methods using liquid chromatography with tandem mass spectrometry (LC-MS/MS) and liquid chromatography high-resolution mass spectrometry (LC-HRMS); (2) determining total PFAS via the Total Oxidizable Precursor assay; and, (3) determining total PFAS via Total Extractable Organic Fluorine content. We will also illustrate to what extent current sample storage and hold time protocols, sample preparation procedures, and instrumental methods for legacy PFAS can be transferred as-is to dozens of newly-identified polyfluorinated analytes.

“Assessing and Mitigating Bias in PFAS Levels during Ground and Surface Water Sampling” by Dr. Jennifer Field (SERDP Project ER19-1205) 

This presentation will cover a SERDP project aimed at determining the factors that impact PFAS stratification in water columns (wells and surface water) that may result in artifacts in measured PFAS concentrations. The project team is conducting laboratory experimentation on model groundwater wells and surface water to identify sampling approaches that may introduce bias. Field sampling materials were extracted and analyzed for PFAS background, and databases on field equipment blanks were examined to look for pattens of PFAS background. Field sampling of surface water was conducted to determine if the presence of foam or surface microlayer has the potential to impact measured PFAS in bulk surface water. Other issues, such as storage of samples with and without headspace, are also being examined. As shown by results to date, the greatest potential for impacting measured PFAS concentrations includes foam or the microlayer when sampling surface waters. Equipment blanks from 67 Department of Defense (DoD) bases indicate no systemic bias introduced by field sampling, and stratification in model groundwater wells does not impact measured PFAS concentrations with wells. Field sampling materials are unlikely to cause positive PFAS artifacts unless they come in direct contact with the actual sample. Sampling guidance is being refined to reflect the new findings and offer a science-based alternative to current restrictive field sampling guidance documents.

Janice Willey is a senior chemist for Naval Sea Systems Command’s (NAVSEA) Laboratory Quality and Accreditation Office (LQAO) in Charleston, South Carolina. Ms. Willey’s current areas of focus is PFAS sampling and analysis. She has served as a member of the SERDP and ESTCP PFAS Working Group, providing technical review of SERDP- and ESTCP-funded projects. She is the quality assurance Manager of the SERDP-funded project responsible for validating an isotope dilution LC-MS/MS method for PFAS in a variety of environmental media. Ms. Willey is the co-chair of the Interstate Technology & Regulatory Council (ITRC) PFAS Sampling and Analysis Subgroup and a trainer for the ITRC’s “Managing PFAS Contamination at Your Site” training course. She earned a bachelor's degree in biochemistry from Clemson University in Clemson, South Carolina.

Dr. Jinxia Liu is an associate professor of civil engineering, a Chwang-Seto Faculty Scholar, and the director of the Brace Center at McGill University in Montreal, Canada. Dr. Liu’s current areas of research focus on developing analytical methods for emerging pollutants (including PFAS and microplastics), the environmental fate of organic contaminants in natural and engineered systems, and the development of in situ and ex situ remediation technologies for PFAS. Dr. Liu has served as the principal investigator on dozens of research grants and contracts focused on PFAS environmental research, including several SERDP and ESTCP projects. She has authored more than 50 peer-reviewed research papers and several governmental reports. She earned a bachelor's degree and a master's degree in environmental engineering from Tianjin University in China and a doctoral degree in agronomy with a focus on environmental chemistry from Purdue University in West Lafayette, Indiana.

Dr. Jennifer Field is a professor in the department of environmental and molecular toxiciology at Oregon State University. Dr. Field’s current research focuses on the development and application of quantitative analytical methods for organic micropollutants and their transformation products in natural and engineered systems with a focus PFAS. Early in her career, she focused on field-based research to investigate the fate and transport of surfactants in groundwater and wastewater treatment systems. She participated in interdisciplinary research with hydrologists and engineers in order to develop tracer test methods for determining in situ rates of reductive dechlorination and anaerobic biodegradation of aromatic hydrocarbons. Dr. Field was a pioneer in the area of PFAS occurrence and behavior with a focus on groundwater contaminated by fire-fighting foams, municipal wastewater treatment systems, and in municipal landfill leachates. She serves as an executive editor for Environmental Science and Technology and was an editor for Water Research between 2004 and 2008. Dr. Field earned her doctoral degree in geochemistry from the Colorado School of Mines.