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This SERDP and ESTCP webinar focuses on DoD-funded research to differentiate between sources of per- and polyfluoroalkyl substances (PFAS) detected in impacted water. Specifically, investigators will discuss two approaches for differentiating between aqueous film-forming foam (AFFF) and non-AFFF sources.



“Comprehensive Forensic Approach for Source Allocation of Poly- and Perfluoroalkyl Substances” by Dr. Chris Higgins  (SERDP Project ER20-1375)  

The DoD, site managers, and other stakeholders would benefit from a scientifically defensible and statistically sound approach for distinguishing whether PFAS in impacted waters is from aqueous film-forming foam (AFFF) or non-AFFF sources. This project investigated whether different types of sources have sufficiently different relative abundances of PFAS compounds such that a general chemical “fingerprint” of each source. The presentation discussed the development of a targeted method that measures the relatively few PFAS compounds contained in the “Forensic LC-MS/MS PFAS Panel” to differentiate between most AFFF and non-AFFF sources. To advance this forensic panel, the project team created a database of PFAS abundance in discrete PFAS sources (i.e., AFFF, landfill leachate, municipal wastewater effluent, and biosolid leachate). This database is combined with a comprehensive PFAS transformation pathway map to establish the context and linkages between specific PFASs and discrete sources; multivariate analyses for use in PFAS source allocation; and a curated high resolution mass spectrometry PFAS library.

“A Simple and Robust Forensic Technique for Differentiating PFAS Associated with AFFF from other PFAS Sources” by Dr. David Sedlak (SERDP Project ER20-1330)  

In some situations, the sources of PFAS detected in impacted water are difficult to identify. Over the past decade, forensic efforts have focused on three approaches: measurements of specific PFAS compounds (e.g., PFOS, PFOA , 8:2FtS), presence of compounds that are known to co-occur with PFAS from certain sources (e.g., pharmaceutical compounds in municipal wastewater), or features in non-target analysis for source attribution. The total oxidizable precursor (TOP) analysis is a robust and readily available method of quantifying a variety of PFAS that are not routinely measured. This presentation discussed approaches for increasing confidence in results from the TOP assay and expanding it to provide additional information that can be used for PFAS source forensics. By using statistical tools such as exploratory data analysis and diversity indices with the TOP assay, the PFAS forensics tools developed under this project are accessible to researchers and practitioners in situations where specialized instrumentation (e.g., high-resolution mass spectrometry) is impractical. 


Speaker Biographies 
Dr. Christopher P. Higgins

Dr. Christopher P. Higgins is an environmental chemist and a professor of civil and environmental engineering at the Colorado School of Mines. His research focuses on the movement and bioaccumulation of contaminants in the environment. In particular, Dr. Higgins studies chemical fate and transport in natural and engineered systems with a focus on PFAS. Dr. Higgins has authored or co-authored over 100 peer-reviewed publications and was awarded the 2019 Huber Prize by the American Society of Civil Engineers for his research contributions. Dr. Higgins was the principal investigator for the SERDP 2020 Environmental Restoration Project of the Year. He earned his bachelor’s degree in chemistry and chemical biology from Harvard, and he received his master’s and doctoral degrees in civil and environmental engineering from Stanford University.


Dr. Davis Sedlak

Dr. David Sedlak is the Plato Malozemoff Professor in the department of civil and environmental engineering at the University of California, Berkeley. He also serves as the Co-Director of the Berkeley Water Center and Deputy Director of the National Science Foundation (NSF) Engineering Research Center for Reinventing the Nation’s Urban Water Infrastructure (ReNUWIt). His research interests include in situ chemical oxidation, advanced water treatment, nature-based water treatment and the development of analytical approaches for identifying contaminants of emerging concern. Dr. Sedlak is a member of the National Academy of Engineering and recipient of numerous awards, including the Paul Busch Award for Innovation in Applied Water Quality Research and the Clarke Prize for Excellence in Water Research. He is also the author of Water 4.0: The Past, Present and Future of the World’s Most Vital Resource. Dr. Sedlak received his bachelor’s degree in environmental science from Cornell University and his doctoral degree in water chemistry from the University of Wisconsin at Madison.