<scp>PFAS</scp> Forensics, Part 2: Analytical Tools and Data Analysis for Source Attribution

Abstract Successfully attributing per‐ and polyfluoroalkyl substances (PFAS) contamination to specific sources may require employing advanced analytical techniques and interpreting complex multivariate datasets. This paper, the second in a series on PFAS forensics, presents some of the analytical and data analysis tools practitioners use to identify source‐specific signatures and differentiate potential contamination sources. Advanced analytical approaches (i.e., chemical forensics) include indicator compound identification, isomer analysis, Total Oxidizable Precursors (TOP) Assay, and high‐resolution mass spectrometry. Each technique can reveal different aspects of PFAS source characteristics, with the forensic value increasing as a combination of methods is applied. Data analysis frameworks (i.e., data forensics), including exploratory data analysis, proportional ratio analysis, visualization techniques, and multivariate statistical methods such as principal component analysis, hierarchical cluster analysis, and receptor modeling, can reveal forensic insights from these analytical results. Effective PFAS forensics requires an understanding of what analytical methods can measure and how to interpret resulting data within the context of site history, transformation pathways, and fate and transport mechanisms. The integration of advanced analytical techniques with systematic data interpretation often provides a foundation for defensible source attribution to inform site management decisions.