Per- and polyfluoroalkyl substances (PFAS) in white-tailed sea eagle eggs from Sweden: temporal trends (1969–2021), spatial variations, fluorine mass balance, and suspect screening

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.

Section: Resultssupporting

confidence: 93%

Section: Tissue Distributionmentioning

confidence: 99%

Concentrations of 45 Per- and Polyfluoroalkyl Substances in North American River Otters (Lontra canadensis) from West Virginia, USA

Li,

Roos,

Serfass

et al. 2024

“…With the exception of the chlorine substituted substances and d-diO/C-diO/K–O PFSA n = 9, most of the aforementioned suspects were previously identified in various marine mammals from Greenland and Sweden by Spaan et al Cl-PFCAs have been previously detected in wastewater from fluorochemical manufacturing parks, , fish from the Yangtze river, and eggs of white-tailed sea eagle . Cl-PFSAs have also been previously identified in wastewater from a fluorochemical manufacturing park and in firefighters, and Cl-PFOS specifically has been identified in samples of marine mammals from the south China sea .…”

Section: Resultsmentioning

confidence: 96%

“…Across all Greenlandic samples, PFAS profiles were dominated by PFOS (up to 94 ng/g), PFUnDA (up to 66 ng/g), and PFTriDA (up to 58 ng/g), which collectively accounted for ∼72% of ∑PFAS (and ∼90% when including all PFCAs), consistent with prior observations in cetaceans from the Nordic environment. , Swedish dolphins also displayed high PFOS concentrations (up to 300 ng/g) but with significant contributions from 7:3 FTCA (up to 220 ng/g) and FOSA (up to 250 ng/g), collectively accounting for ∼80% of ∑PFAS (Figure S3). 7:3 FTCA is a stable transformation product of fluorotelomer alcohols − and has been previously measured in marine mammals and seabirds globally, − ,,− while FOSA has been previously reported at elevated concentrations in cetaceans ,,,, due to the limited capacity of these species to biotransform FOSA into PFOS. , …”

Section: Resultsmentioning

confidence: 99%

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Closing the Organofluorine Mass Balance in Marine Mammals Using Suspect Screening and Machine Learning-Based Quantification

Lauria,

Sepman,

Ledbetter

et al. 2024

Self Cite

High-resolution mass spectrometry (HRMS)-based suspect and nontarget screening has identified a growing number of novel per-and polyfluoroalkyl substances (PFASs) in the environment. However, without analytical standards, the fraction of overall PFAS exposure accounted for by these suspects remains ambiguous. Fortunately, recent developments in ionization efficiency (IE) prediction using machine learning offer the possibility to quantify suspects lacking analytical standards. In the present work, a gradient boosted tree-based model for predicting log IE in negative mode was trained and then validated using 33 PFAS standards. The root-mean-square errors were 0.79 (for the entire test set) and 0.29 (for the 7 PFASs in the test set) log IE units. Thereafter, the model was applied to samples of liver from pilot whales (n = 5; East Greenland) and white beaked dolphins (n = 5, West Greenland; n = 3, Sweden) which contained a significant fraction (up to 70%) of unidentified organofluorine and 35 unquantified suspect PFASs (confidence level 2−4). IE-based quantification reduced the fraction of unidentified extractable organofluorine to 0−27%, demonstrating the utility of the method for closing the fluorine mass balance in the absence of analytical standards.

Four Decades of Spatiotemporal Variability of Per- and Polyfluoroalkyl Substances (PFASs) in the Baltic Sea

Soerensen,

Benskin,

Faxneld

2024

Self Cite

Temporal and spatial variability of per- and polyfluoroalkyl substances (PFASs) in herring, cod, eelpout, and guillemot covering four decades and more than 1000 km in the Baltic Sea was investigated to evaluate the effect of PFAS regulations and residence times of PFASs. Overall, PFAS concentrations responded rapidly to recent regulations but with some notable basin- and homologue-specific variability. The well-ventilated Kattegat and Bothnian Bay showed a faster log-linear decrease for most PFASs than the Baltic Proper, which lacks a significant loss mechanism. PFOS and FOSA, for example, have decreased with 0–7% y–1 in the Baltic Proper and 6–16% y–1 in other basins. PFNA and partly PFOA are exceptions and continue to show stagnant or increasing concentrations. Further, we found that Bothnian Bay herring contained the highest concentrations of >C12 perfluoroalkyl carboxylic acids (PFCAs), likely from rivers with high loads of dissolved organic carbon. In the Kattegat, low PFAS concentrations, but a high FOSA fraction, could be due to influence from the North Sea inflow below the halocline and possibly a local source of FOSA and/or isomer-specific biotransformation. This study represents the most comprehensive spatial and temporal investigation of PFASs in Baltic wildlife while providing new insights into cycling of PFASs within the Baltic Sea ecosystem.