In
this study, we evaluate the main factors driving the exposure of Southern
Ocean seabirds to perfluoroalkyl substances (PFASs) across a wide
geographic range. Five perfluoroalkane sulfonates (PFSAs, C4–12), 10 perfluoroalkyl carboxylic acids (PFCAs, C4–13), and perfluorooctane sulfonamide (FOSA) were analyzed in plasma
(n = 128) from eight species, including penguins,
giant petrels, skuas, albatrosses, and shearwaters, breeding at four
sites in the Antarctic, sub-Antarctic, and adjacent cool-temperate
regions. Mean ∑PFAS concentrations ranged from 0.53 to 53 ng/g
wet weight from black-browed albatross to giant petrels, respectively.
As expected due to biomagnification, greater concentrations of most
PFASs were found in species near the top of marine food webs such
as giant petrels. However, our results suggest that other factors,
i.e., metabolic capabilities and spatial movements, can mask interspecies
differences in PFASs, especially PFCAs, expected from trophic structure.
For instance, trans-equatorial migratory seabirds exhibited PFAS levels
and profiles that are consistent with northern hemisphere exposure,
reflecting their potential biovector role in the global transport
of these pollutants. Among resident species, greater concentrations
of PFASs, especially long-chain PFCAs, were found in seabirds breeding
or foraging north of the Antarctic Circumpolar Current (ACC) than
in those restricted to Antarctic/sub-Antarctic distributions. Moreover,
composition profiles of PFAS in Antarctic seabirds agree well with
those expected from long-range transport. Our results confirm the
importance of the ACC in protecting Antarctic food webs from water-phase-transported
PFASs.