North American river otters (Lontra canadensis) are top predators in riverine ecosystems and are vulnerable to
per- and polyfluoroalkyl substance (PFAS) exposure. Little is known
about the magnitude of exposure and tissue distribution of PFAS in
river otters. We measured 45 PFAS in various tissues of 42 river otters
collected from several watersheds in the state of West Virginia, USA.
The median concentrations of ∑All (sum concentration of 45
PFAS) varied among tissues in the following decreasing order: liver
(931 ng/g wet weight) > bile > pancreas > lung > kidney
> blood >
brain > muscle. Perfluoroalkylsulfonates (PFSAs) were the predominant
compounds accounting for 58–75% of the total concentrations,
followed by perfluoroalkyl carboxylates (PFCAs; 21–35%). 8:2
fluorotelomer sulfonate (8:2 FTS), 10:2 FTS, and 6:2 chlorinated polyfluoroalkyl
ether sulfonate were frequently found in the liver (50–90%)
and bile (96–100%), whereas hexafluoropropylene oxide dimer
acid (HFPO-DA) was rarely found. The hepatic concentrations of ∑All
in river otters collected downstream of a fluoropolymer production
facility located along the Ohio River were 2-fold higher than those
in other watersheds. The median whole body burden of ∑All was
calculated to be 1580 μg. PFOS and perfluorooctanoic acid (PFOA)
concentrations in whole blood of some river otters exceeded the human
toxicity reference values, which warrant further studies.