From 1980 to 2017, Wilmington, North Carolina (NC), residents unknowingly consumed high levels of PFAS through drinking water. Some of these PFAS are expected to have short biological half-lives, and current biological sampling will miss these exposures. To assess historical PFAS exposures, we (1) determined PFAS levels in serum samples of Wilmington, NC residents obtained during the years 2010-2016, (2) examined temporal trends of serum PFAS over this period, and (3) associated serum PFAS levels with PFAS concentrations in drinking water. We quantified 56 PFAS, including ultrashort-chain PFAS, in 119 adult human serum samples and 47 PFAS in water samples from 2017. Twenty PFAS were detected in >50% of serum samples; perfluoromethoxyacetic acid (PFMOAA) and trifluoroacetic acid (TFA) exhibited the highest median concentrations (PFMOAA: 42 ng/mL; TFA: 17 ng/mL). PFMOAA and TFA were also the dominant PFAS in Wilmington drinking water, accounting for 95% of quantifiable PFAS. The serum-to-water ratio was linearly correlated with "effective" PFAS chain length, indicating that PFAS with longer chain length and a sulfonic acid group are more bioaccumulative. While chain length is important for bioaccumulation, this study highlights that exposures to high concentrations of ultrashort-chain PFAS in drinking water contribute to their dominance in human serum.

A community engaged research (CER) approach was used to provide an exposure assessment of poly- and perfluorinated (PFAS) compounds in North Carolina residential drinking water. Working in concert with community partners, who acted as liaisons to local residents, samples were collected by North Carolina residents from three different locations along the Cape Fear River basin: upper, middle, and lower areas of the river. Residents collected either drinking water samples from their homes or recreational water samples from near their residence that were then submitted by the community partners for PFAS analysis. All samples were processed using weak anion exchange (WAX) solid phase extraction and analyzed using a non-targeted suspect screening approach as well as a quantitative approach that included a panel of 45 PFAS analytes, several of which are specific to chemical industries near the collection site locations. The non-targeted approach, which utilized a suspect screening list (obtained from EPA CompTox database) identified several PFAS compounds at a level two confidence rating (Schymanski scale); compounds identified included a fluorinated insecticide, a fluorinated herbicide, a PFAS used in polymer chemistry, and another that is used in battery production. Notably, at several locations, PFOA (39.8 ng/L) and PFOS (205.3 ng/L) were at levels that exceeded the mandatory EPA maximum contaminant level (MCL) of 4 ng/L. Additionally, several sites had detectable levels of PFAS that are unique to a local chemical manufacturer. These findings were communicated back to the community partners who then disseminated this information to the local residents to help empower and aid in making decisions for reducing their PFAS exposure.

Presented data shows that vacuum evaporative concentration of PFAS standards can cause class-specific loss of material that can be mitigated via recovery steps.

Rationale: The ability to perform absolute quantitation and non‐targeted analysis on a single mass spectrometry instrument would be advantageous to many researchers studying per‐ and polyfluoroalkyl substances (PFAS). High‐resolution accurate mass (HRAM) instrumentation (typically deployed for non‐targeted work) carries several advantages over traditional triple quadrupole workflows when performing absolute quantitation. Processing this data using a vendor‐neutral software would promote collaboration for these environmental studies. Methods: LC‐MS (Orbitrap Exploris 240) was used for absolute quantitation of 45 PFAS using precursor (MS1) peak areas for quantitation, whereas isotope pattern matching and fragmentation (MS2) pattern matching were used for qualitative identification. In addition, a fluorinated chromatographic column achieved superior separation compared to the typical C18 columns typically used in PFAS analyses. This method was validated across eight different chemical classes using recommended guidelines found in EPA Method 537.1 and Skyline data processing software. Results: The validated limits of all 45 compounds, as well as metrics or accuracy and reproducibility, are reported. Most compounds achieved limits of quantitation in the range of 2‐50 ng/L. Four newly released Chemours‐specific compounds (PEPA, PFO3OA, PFO4DA, and PFO5DoA) were also validated. Aspects of data analysis specific to high resolving power absolute quantitation are reviewed as are the details of processing these data via Skyline. Conclusions: This method shows the feasibility of performing reproducible absolute quantitation of PFAS on an HRAM platform and does so using an open‐source vendor‐neutral data processing software to facilitate sharing of data across labs and institutions.