Bioaccumulation and biomagnification of perfluoroalkyl acids and precursors in East Greenland polar bears and their ringed seal prey

• Published in: Environmental pollution (1987) 2019-09, Vol.252 (Pt B), p.1335-1343
• Main Authors: Boisvert, Gabriel, Sonne, Christian, Rigét, Frank F., Dietz, Rune, Letcher, Robert J.
• Format: Article
• Language: English
• Subjects: Bioaccumulation; East Greenland; Perfluorinated acids; PFOS; Polar bear; Ringed seal
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2019.06.035

The bioaccumulation and biomagnification of 22 major perfluoroalkyl substances (PFAS) were investigated in tissues of polar bears (Ursus maritimus) and their major prey species, the ringed seal (Pusa hispida), from the Scoresby Sound region of East Greenland. In polar bear liver the mean Σ4PFSA (perfluoroalkyl sulfonic acid) concentration (C4, C6, C8 and C10) was 2611 ± 202 ng/g wet weight (ww; 99% perfluorooctane sulfonate (PFOS)) and two orders of magnitude higher than the 20 ± 3 ng/g ww (89% PFOS) concentration in fat. The mean Σ4PFSAs in seal liver was 111 ± 5 ng/g ww (98% PFOS) and three orders of magnitude higher relative to the 0.05 ± 0.01 ng/g ww concentration in blubber (100% perfluorohexane sulfonate). Perfluoro-1-octane sulfonamide (FOSA) was quantifiable in bear (mean 10 ± 1.4 ng/g ww) and seal (mean 0.6 ± 0.1 ng/g ww) liver but not in fat or blubber. The mean Σ13PFCAs (C4–C18; perfluoroalkyl carboxylic acids) in bear liver (924 ± 71 ng/g ww) was much greater than in seal liver (74 ± 6 ng/g ww). In bear fat and seal blubber, the mean Σ13PFCAs were 15 ± 1.9 and 0.9 ± 0.1 ng/g ww, respectively. Longer chain C11 to C14 PFCAs dominated in bear fat and seal blubber (60–80% of Σ13PFCA), whereas shorter-chain C9 to C11 PFCAs dominated in the liver (85–90% of Σ13PFCA). Biomagnification factors (BMFs) were orders of magnitude greater for PFHxS and C9 to C13 PFCAs when based on bear liver to seal blubber rather than bear liver to seal liver, and PFCA (C9 to C13) BMFs decreased with increasing chain length. Seal blubber to bear liver BMFs better reflects the dietary exposure relationship of PFAS between bears and seals. [Display omitted] •Major PFASs were compared in liver and fat tissues of polar bears and ringed seals.•Polar bears had greater PFAS contamination than ringed seals.•The PFOS to precursor FOSA ratio was significantly greater in bears than in seals.•PFCA tissue concentration increased whereas biomagnification factors (BMFs) decreased with increased with PFCA chain length.•Comparing PFAS BMFs based in bear liver to seal blubber better reflects the dietary relationship. Ringed seal to polar bear bioaccumulation and biomagnification of PFCAs, PFSAs (PFOS) and precursors are much greater when based on dietary relationship of seal blubber to bear liver.