Per- and polyfluoroalkyl substances (PFAS) in surface sediments: Occurrence, patterns, spatial distribution and contribution of unattributed precursors in French aquatic environments

Nicolas Macorps; Pierre Labadie; François Lestremau; Azziz Assoumani; Hélène Budzinski

doi:10.1016/j.scitotenv.2023.162493

Per- and polyfluoroalkyl substances (PFAS) in surface sediments: Occurrence, patterns, spatial distribution and contribution of unattributed precursors in French aquatic environments

Sci Total Environ. 2023 May 20:874:162493. doi: 10.1016/j.scitotenv.2023.162493. Epub 2023 Feb 28.

Authors

Nicolas Macorps¹, Pierre Labadie², François Lestremau³, Azziz Assoumani⁴, Hélène Budzinski¹

Affiliations

¹ CNRS/Université de Bordeaux, UMR 5805 EPOC, Talence, France.
² CNRS/Université de Bordeaux, UMR 5805 EPOC, Talence, France. Electronic address: pierre.labadie@u-bordeaux.fr.
³ INERIS, Unité Méthodes et développements en Analyses pour l'Environnement, 60550 Verneuil-en-Halatte, France; Hydrosciences Montpellier, Univ. Montpellier, IMT Mines Ales, IRD, CNRS, Ales, France.
⁴ INERIS, Unité Méthodes et développements en Analyses pour l'Environnement, 60550 Verneuil-en-Halatte, France.

PMID: 36863581
DOI: 10.1016/j.scitotenv.2023.162493

Abstract

While perfluoroalkyl sulfonic acids (PFSAs) and perfluoroalkyl carboxylic acids (PFCAs) are ubiquitous in aquatic environments, non-targeted methods have recently revealed the presence of numerous unidentified per- and polyfluoroalkyl substances (PFAS). Besides those methods, the total oxidizable precursor (TOP) assay has proved useful to estimate the contribution of unattributed perfluoroalkyl acids precursors (pre-PFAAs). In this study, an optimized extraction method was developed to examine the spatial distribution of 36 targeted PFAS in surface sediments collected at French nationwide scale (n = 43), including neutral, anionic and zwitterionic molecules. In addition, a TOP assay procedure was implemented to estimate the contribution of unattributed pre-PFAAs in these samples. Conversion yields of targeted pre-PFAAs were determined for the first time under realistic conditions and led to differences in oxidation profiles compared to the common spiked ultra-pure water method. PFAS were detected in 86 % of samples and ∑PFAS_targeted was in the range < Limit of Detection - 23 ng g^-1 dry weight (dw) (median: 1.3 ng g^-1 dw), with ∑pre-PFAAs_targeted representing on average 29 ± 26 % of ∑PFAS. Among pre-PFAAs, compounds of emerging interest such as the fluorotelomer sulfonamidoalkyl betaines 6:2 FTAB and 8:2 FTAB were respectively detected in 38 % and 24 % of samples, with levels similar to those of L-PFOS (<0.36-2.2, <0.50-6.8 and < 0.08-5.1 ng g^-1 dw, respectively). A hierarchical cluster analysis coupled with a geographic information system-based approach revealed similarities between groups of sampling sites. For instance, elevated contribution of FTABs were associated with the proximity to airport activities where betaine-based aqueous film-forming foam (AFFFs) might have been used. In addition, unattributed pre-PFAAs were strongly correlated with ∑PFAS_targeted and they accounted for 58 % of ∑PFAS (median value); they were generally found in larger quantity near industrial and urban areas where the highest ∑PFAS_targeted were also observed.

Keywords: Emerging contaminants; Hierarchical cluster analysis; PFAS; Sediment; TOP assay.