Suspect Screening of PFAS in French Coastal Bivalves: In-Depth Detection and Annotation Using Aqueous Film-Forming Foams

Numerous
per- and polyfluoroalkyl substances (PFAS) are highly
persistent and mobile in the aquatic environment, making the oceans
a major sink for contamination. This study presents an in-depth suspect
screening of PFAS in marine mussels and oysters from 23 sites along
the French coasts, using aqueous film-forming foams (AFFFs) as reference
materials. The approach proved effective in revealing precursors that
may be metabolized by organisms of higher trophic levels. Overall,
79 PFAS across 29 classes were identified, including 15 classes (e.g., X:2 FTSAm) reported for the first time in marine biota.
The use of AFFFs supported not only the detection of PFAS but also
their structural annotation, notably by distinguishing per- from polyfluoroalkyl
compounds. Several PFAS detected in bivalves, such as 6:2 diPAP and
X:3 FTCA, were not found in AFFFs, which suggested the existence of
alternative sources and/or environmental degradation processes. Spatial
analysis revealed contrasting contamination profiles, in particular
PFAS hotspots near industrialized and estuarine areas, and lower levels
at less-industrialized sites or those further from the coast. Detection
of currently unmonitored PFAS (e.g., 6:2 FTAB and
FHxSA) at all sampling sites highlighted the urgent need to broaden
the scope of PFAS studies for a more comprehensive environmental assessment.