Formatted Title
Forensic Tools for Identifying PFAS Manufacturing Sources in the Environment
Background/Objectives
Manufacturing methods of per- and polyfluoroalkyl substances (PFAS) may present certain analytical indicators that identify their manufacturing origin, whether present in products or in the environment. For example, linear and branched isomer composition of PFAS is one tool that can be used to identify potential manufacturing sources of PFAS. Depending on the manufacturing process, branched and/or linear isomers of certain PFAS are produced. Electrochemical fluorination (ECF) yields a mixture of branched and linear isomers, while fluorotelomerization (FT) generates predominantly linear PFAS. Given the resulting compositional differences, analysis of branched and linear PFAS has been suggested as one environmental forensic approach for identifying the manufacturing sources of PFAS and for allocating responsibility among potentially responsible parties. Other indicators may aid in identifying manufacturing sources as well.
While the potential exists to use branched and linear isomer data for PFAS source identification, limitations exist in current analytical methods to reliably quantify branched PFAS isomers. The current understanding of the differences in the fate and transport behavior of branched and linear PFAS is also limited. These limitations, if not considered during the interpretation of data, may lead to uncertainties in identifying and allocating liability among PFAS sources.
Approach/Activities
As a forensic tool, branched and linear PFAS analysis may be a promising method to identify manufacturing sources; however, the potential limitations may need to be understood on a case-by-case basis and the source identification accompanied by additional lines of evidence. This presentation will briefly summarize currently available analytical methods for branched and linear PFAS isomers and current understanding of their fate and transport behavior in the environment. The presentation will also explore gaps in current research and identify key areas of investigation that may be needed for defensible use of branched and linear isomers for PFAS source identification.
Results/Lessons Learned
A case study describing the forensic identification of manufacturing sources of PFAS to a large watershed will be discussed. The quantitative application of linear and branched PFAS isomer analysis paired with other manufacturing method lines of evidence was incorporated into a mass balance model for upstrem identification of sources.