Per‐ and poly‐fluoroalkyl substances (PFAS) are a broad class of environmentally persistent chemicals that include thousands of potentially toxic synthetic organic molecules. Some PFAS have been shown to cause adverse health effects including decreased total cholesterol, birth weight, and reproductive success in laboratory animals; however, a lack of chronic toxicity data exists for PFAS in avian ecological receptors. The present study reports on the chronic toxicity of perfluorooctane sulfonic acid (PFOS) and a mixture of PFOS and perfluorohexane sulfonic acid (PFHxS) to northern bobwhite quail (Colinus virginianus) via oral exposure from drinking water. Female weight gain was adversely affected at an average daily intake (ADI) of 3.10 × 10−3 ± 0.15 × 10−3 mg PFOS:PFHxS (1.2:1) mixture × kg−1 body weight × d−1. Successful liberation from the shell once pipped was adversely affected at an ADI of 2.45 × 10−3 ± 0.01 × 10−3 mg PFOS x kg−1 body weight × d−1. These values are comparatively much lower than the current dietary avian toxicity reference value (TRV) derived from birds that were exposed via feed, suggesting the need for updated avian TRVs. Relationships between test chemical (PFOS) and test substance (PFOS:PFHxS) showed that PFOS and PFHxS have possible interacting effects in avian receptors and likely differing mechanisms of toxicity depending on chemical co‐occurrence and dose. Both the single‐chemical and mixture exposures produced similar and possibly additive toxicity values. Environ Toxicol Chem 2020;39:1101–1111. © 2020 SETAC

Information is needed on the concentration of per- and polyfluoroalkyl substances (PFAS) in foams on surface waters impacted by aqueous film-forming foam (AFFF). Nine pairs of foam and underlying bulk water were collected from a single freshwater lake impacted by PFAS and analyzed for PFAS by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QToF) and for dissolved organic carbon (DOC). The DOC of two foam:bulk water pairs was characterized by 1H NMR. Foams were comprised of 16 PFAS with concentrations as high as 97 000 ng/L (PFOS) along with longer-chain, more hydrophobic PFAS. Only five PFAS (PFOS and shorter chain lengths) were quantified in underlying bulk waters. Enrichment factors (foam:bulk water) ranged from 10 (PFHxA) up to 2830 (PFOS). Foams impacted by AFFF gave the greatest concentrations and number of PFAS classes with PFOS concentrations exceeding the EPA health advisory level (70 ng/L). PFAS concentrations were significantly below published critical micelle concentrations and constituted <0.1% of overall DOC concentrations in foam, indicating that PFAS are a minor fraction of DOC and that DOC likely plays a central role in foam formation. Estimates indicate that foam ingestion is a potentially important route of exposure for children and adults when they are in surface waters where foam is present.

Volatile per- and polyfluorinated alkyl substances (PFASs) are found in consumer goods that contribute to human exposure to PFASs. Volatile PFAS precursors transform to perfluorinated carboxylates (PFCAs) and sulfonates (PFSAs) in both humans and the environment. Established methods for volatile PFASs in consumer goods exist, but higher sample throughput and greener sample preparation methods are needed to minimize analyte loss, while maintaining sensitivity. New analytical methodology was developed where a 1.5 × 1.5 cm piece of paper or textile is placed into an autosampler vial with solvent and mass-labeled internal standards, sonicated for 30 min, and directly injected without removal of material from the autosampler vial. Large volume injection (20 μL) gas chromatography mass spectrometry was applied for the quantification for 21 individual PFASs from five classes: fluorotelomer alcohols (FTOHs), fluorinated sulfonamides (N-MeFASA, N-EtFASA), and fluorinated sulfonamidoethanols (N-MeFASE, N-EtFASE). Nontargeted analysis revealed additional C-C homologues of N-MeFASE and N-EtFASE, which accounted for 14-18% of the total volatile PFASs on three textiles. Overlooking short-chain (≤C) N-MeFASE, N-EtFASE, and long-chained (10:2-14:2) FTOHs on older textiles from the 1980s leads to an underestimation of human and environmental exposure to volatile PFAS.

Toxicity reference values for per‐ and polyfluoroalkyl substances (PFAS) vary even when the same test organism is studied. Although the need to confirm dosing solution concentrations is widely accepted, there are no experimental data to inform best practices when PFAS solutions are prepared. Laboratory data indicate that dissolution time of PFAS solids causes statistically significant deviations between nominal and measured concentrations. Mixing times for select PFAS varied between 2 and 5 h, depending on carbon fluorine chain‐length. Environ Toxicol Chem 2021;40:677–688. © 2020 SETAC

Few studies have determined the toxicity of perfluoralkyl substances (PFAS) to aquatic invertebrates. We exposed Chironomus dilutus to 6 different PFAS to assess single-chemical toxicity and relative or proportional toxicity among substances. A 10-d range-finding test was conducted to inform 20-d assays for the following PFAS: perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorobutanesulfonic acid (PFBS), perfluorohexanesulfonic acid (PFHxS), and perfluoroheptanoic acid (PFHpA). A 20-d binary mixture study of PFOS+PFHxS followed the single-chemical tests. Measurement endpoints for 20-d tests included larval survival and biomass. Log-logistic concentration response models were used to estimate 10, 20, and 50% effect concentrations (EC20, EC50) for PFOS, PFHxS, and PFOA. Survival EC50s for PFOS, PFHxS, and PFOA were 2.49, 3860, and 192 000 µg/L, respectively, whereas survival EC20s were 1.70, 913, and 119 000 µg/L for PFOS, PFHxS, and PFOA, respectively. Biomass as a combined survival and growth endpoint resulted in EC20s of 1.89, 896, and 137 000 µg/L for PFOS, PFHxS, and PFOA, respectively. Maximum concentrations tested (no-observed-effect concentrations) for PFNA, PFBS, and PFHpA were 2 to 3 orders of magnitude greater than the PFOS EC50s and showed no toxicity to C. dilutus, even at exposure concentrations well above what would be considered environmentally relevant. The binary mixture of 2.5 µg/L PFOS+1000 µg/L PFHxS showed reduced survival compared to controls and some indication of potential additive or synergistic interaction between PFOS and PFHxS. Overall, the present study supports previous studies showing PFOS to be the most toxic PFAS to aquatic life and suggests that PFOS could be more toxic to the freshwater midge than previously reported.