peer reviewed | We found plastic debris in the stomach of an Arctic seal pup for the first time. Debris consisted of two pieces of light single-use plastic. Newborns of Arctic seals are at risk of exposure to plastic directly after weaning. Ecotoxicological investigations of plastic exposure to Arctic wildlife are needed.

A selection of PCN congeners was analyzed in pooled blubber samples of pilot whale (Globicephala melas), ringed seal (Phoca hispida), minke whale (Balaenoptera acutorostrata), fin whale (Balaenoptera physalus), harbour porpoise (Phocoena phocoena), hooded seal (Cystophora cristata) and Atlantic white-sided dolphin (Lagenorhynchus acutus), covering a time period of more than 20 years (1986–2009). A large geographical area of the North Atlantic and Arctic areas was covered. PCN congeners 48, 52, 53, 66 and 69 were found in the blubber samples between 0.03 and 5.9 ng/g lw. Also PCBs were analyzed in minke whales and fin whales from Iceland and the total PCN content accounted for 0.2% or less of the total non-planar PCB content. No statistically significant trend in contaminant levels could be established for the studied areas. However, in all species except minke whales caught off Norway the lowest ∑PCN concentrations were found in samples from the latest sampling period.

The objective of the present study was to investigate recent concentrations of perfluoroalkyl substances (PFASs) in white whales (Delphinapterus leucas) from Svalbard and compare them to concentrations found in white whales sampled from that same area 15 years ago. Plasma collected from live-captured white whales from two time periods (2013–2014, n = 9, and 1996–2001, n = 11) were analysed for 19 different PFASs. The 11 PFASs detected included seven C₈–C₁₄ perfluoroalkyl carboxylates (PFCAs) and three C₆–C₈ perfluoroalkyl sulfonates (PFSAs) as well as perfluorooctane sulfonamide (FOSA). Recent plasma concentrations (2013–2014) of the dominant PFAS in white whales, perfluorooctane sulfonate (PFOS; geometric mean = 22.8 ng/mL), was close to an order of magnitude lower than reported in polar bears (Ursus maritimus) from Svalbard. PFOS concentrations in white whales were about half the concentrations in harbour (Phoca vitulina) and ringed (Pusa hispida) seals, similar to hooded seals (Cystophora cristata) and higher than in walruses (Odobenus rosmarus) from that same area. From 1996 to 2001 to 2013–2014, plasma concentrations of PFOS decreased by 44%, whereas four C₉₋₁₂ PFCAs and total PFCAs increased by 35–141%. These results follow a similar trend to what has been reported in other studies of Arctic marine mammals from Svalbard. The most dramatic change has been the decline of PFOS concentrations since 2000, corresponding to the production phase-out of PFOS and related compounds in many countries around the year 2000 and a global restriction on these substances in 2009. Still, the continued dominance of PFOS in white whales, and increasing concentration trends for several PFCAs, even though exposure is relatively low, calls for continued monitoring of concentrations of both PFCAs and PFSAs and investigation of biological effects.

There is a general lack of information on the possible effects of perfluoroalkyl substances (PFASs) on thyroid hormones (THs) in wildlife species. The effects of PFASs, which are known endocrine disruptors, on the TH homeostasis in hooded seals (Cystophora cristata) have yet to be investigated. Previously, correlations were found between plasma thyroid hormone (TH) concentrations in hooded seals, and organohalogen contaminants (OHCs) and hydroxyl (OH)-metabolites. Because animals are exposed to multiple contaminants simultaneously in nature, the effects of the complex contaminant mixtures that they accumulate should be assessed. Herein, we analyse relationships between plasma concentrations of multiple contaminants including protein-associated PFASs, hydroxylated metabolites of polychlorinated biphenyls (OH-PCBs) and lipid soluble OHCs and plasma concentrations of free and total THs, i.e. triiodothyronine (FT3, TT3) and thyroxine (FT4, TT4) in hooded seal mothers and their pups. The perfluoroalkyl carboxylates (PFCAs) were the most important predictors for FT3 concentrations and TT3:FT3 ratios in the mothers. The FT3 levels decreased with increasing PFCA levels, while the TT3:FT3 ratios increased. In the pups, hexachlorocyclohexanes (HCHs) were the most important predictors for TT3:FT3 ratios, increasing with increasing HCHs levels. Additionally, perfluoroalkyl sulfonates (PFSAs) and PFCAs were important predictors for FT4:FT3 ratios in hooded seal pups, and the ratio increased with increasing concentrations. The study suggests that PFASs contribute to thyroid disruption in hooded seals exposed to complex contaminant mixtures that include chlorinated and fluorinated organic compounds.