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

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 (Pula hispida), from the Scoresby Sound region of East Greenland. In polar bear liver the mean Sigma(13)PFSA (per-fluoroalkyl sulfonic acid) concentration (C-4, C-6, C-8 and C-10) 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 ERFSAs 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-l-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 Sigma 13PFCAs (C4-C 1 9; 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 Sigma 13PFCAs were 15 +/- 1.9 and 0.9 +/- 0.1 ng/g ww, respectively. Longer chain C(11 )to C-14 PFCAs dominated in bear fat and seal blubber (60-80% of Sigma(13)PFCA), whereas shorter-chain C-9 to C-11 PFCAs dominated in the liver (85-90% of Sigma(13)PFCA). Biomagnification factors (BMFs) were orders of magnitude greater for PFHxS and C-9 to C-13 PFCAs when based on bear liver to seal blubber rather than bear liver to seal liver, and PFCA (C-9 to C-13) BMFs decreased with increasing chain length. Seal blubber to bear liver BMFs better reflects the dietary exposure relationship of PFAS between bears and seals. (C) 2019 Elsevier Ltd. All rights reserved.