Sediment Cores and Surface Sediments Witnesses Past and Present OPEs and PFAS Pollution in the French Atlantic Coast

Abstract Organophosphate esters (OPEs), flame retardants and plasticizers, and per- and polyfluoroalkyl substances (PFAS) exhibit a high capacity to accumulate in marine sediments. In this study, both sediment cores and surface sediments were collected in 2022 to establish their periods of first detection, background concentrations, and spatial-temporal evolution on the French Atlantic coast. Altogether, our results indicate the early presence of these chemicals in the area, but their level evolution over time and current concentrations in sediments (0.1–15.1 and 0.04–3.56 ng/g dw for ∑tri-OPEs and ∑PFAS, respectively) show a moderate-to-low pollution scenario. The concentrations of both contaminant families peaked in the inner sites of the Loire estuary. The estimated doubling times (and half-lives) indicate a complex compound-dependent situation. For example, the concentrations of tris(2-ethylhexyl) phosphate (TEHP) and perfluorooctanoic acid (PFOA) would double in the study area in approximately 30 years. However, the levels of tris(2-butoxyethyl) phosphate (TBOEP) and bis(2-ethylhexyl) phosphate (BEHP) would be halved in a similar time period. The generated data are of high value in the framework of both European regulations and the Regional Sea Conventions dealing with marine chemical pollution, particularly OSPAR, since these two families of contaminants are not fully addressed at present, and many data gaps exist.