Linear and branched perfluorooctane sulfonate (PFOS) isomer patterns differ among several tissues and blood of polar bears.
Perfluorooctane sulfonate (PFOS) is a globally distributed persistent organic pollutant that has been found to bioaccumulate and biomagnify in aquatic food webs. Although principally in its linear isomeric configuration, 21-35% of the PFOS manufactured via electrochemical fluorination is produced as a branched structural isomer. PFOS isomer patterns were investigated in multiple tissues of polar bears (Ursus maritimus) from East Greenland. The liver (n = 9), blood (n = 19), brain (n = 16), muscle (n = 5), and adipose (n = 5) were analyzed for linear PFOS (n-PFOS), as well as multiple mono- and di-trifluoromethyl-substituted branched isomers. n-PFOS accounted for 93.0 ± 0.5% of Σ-PFOS isomer concentrations in the liver, whereas the proportion was significantly lower (p<0.05) in the blood (85.4 ± 0.5%). Branched isomers were quantifiable in the liver and blood, but not in the brain, muscle, or adipose. In both the liver and blood, 6-perfluoromethylheptane sulfonate (P6MHpS) was the dominant branched isomer (2.61 ± 0.10%, and 3.26 ± 0.13% of Σ-PFOS concentrations, respectively). No di-trifluoromethyl-substituted isomers were detectable in any of the tissues analyzed. These tissue-specific isomer patterns suggest isomer-specific pharmacokinetics, perhaps due to differences in protein affinities, and thus differences in protein interactions, as well transport, absorption, and/or metabolism in the body.
Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Science Directorate, Science and Technology Branch, National Wildlife Research Centre, Environment Canada, Carleton University, Ottawa, ON K1A 0H3, Canada.
Alana K
AK
Greaves
Robert J
RJ
Letcher
D017738:Alkanesulfonic Acids / Q000097:blood / Q000378:metabolism* / Q000493:pharmacokinetics; D000818:Animals; D004785:Environmental Pollutants / Q000097:blood / Q000378:metabolism* / Q000493:pharmacokinetics; D005466:Fluorocarbons / Q000097:blood / Q000378:metabolism* / Q000493:pharmacokinetics; D008401:Gas Chromatography-Mass Spectrometry; D006116:Greenland; D007536:Isomerism; D014018:Tissue Distribution; D001503:Ursidae / Q000378:metabolism*
D017738:Alkanesulfonic Acids; D004785:Environmental Pollutants; D005466:Fluorocarbons; C076994:perfluorooctane sulfonic acid
Blood; Brain; Liver; PFOS isomers and patterns; Perfluorooctane sulfonate; Polar bear