Occurrence of perfluoroalkyl substances (PFASs) in a large number of wild and farmed aquatic animals collected in the Netherlands

Concentrations and human exposure assessment of per and polyfluoroalkyl substances in farmed marine shellfish in South Africa

Although the consumption of seafood is a major route of human exposure to perfluoroalkyl substances (PFAS), data on their concentrations in marine shellfish and the exposure of the African population to PFAS through the consumption of shellfish is lacking. In this study, the concentrations of 15 PFAS were measured in four species of farmed marine shellfish by using a validated UHPLC-MS/MS method. These concentrations were used to determine the human daily intake of PFAS through the consumption of marine shellfish and the hazard quotient thereof. PFPeA, PFOS, PFHxA and PFTeDA were the most prevalent compounds with detection frequencies of 94, 88, 76 and 71%, respectively. The Σ₁₁PFAS concentrations (in ng g^-1 wet weight (ww)) ranged from 0.12 to 0.49, 4.83-6.43, 0.64-0.66 and 0.22 ng g^-1 ww in abalone, mussel, oyster and lobster, respectively. The prevalence of PFCAs reflects the current contamination profile of PFAS in farmed shellfish. The estimated daily intake for Σ₁₀ PFAS through the consumption of marine shellfish ranged from 0.05 to 1.58 ng kg^-1 bw d^-1. Overall, the hazard quotients for these compounds were low, indicating that these compounds do not pose a health risk to the South African population through shellfish consumption. This study provides background data for future studies on the occurrence of PFAS and other emerging contaminants in the African coastal environment.

Bioaccumulation, Biodistribution, Toxicology and Biomonitoring of Organofluorine Compounds in Aquatic Organisms

This review is a survey of recent advances in studies concerning the impact of poly- and perfluorinated organic compounds in aquatic organisms. After a brief introduction on poly- and perfluorinated compounds (PFCs) features, an overview of recent monitoring studies is reported illustrating ranges of recorded concentrations in water, sediments, and species. Besides presenting general concepts defining bioaccumulative potential and its indicators, the biodistribution of PFCs is described taking in consideration different tissues/organs of the investigated species as well as differences between studies in the wild or under controlled laboratory conditions. The potential use of species as bioindicators for biomonitoring studies are discussed and data are summarized in a table reporting the number of monitored PFCs and their total concentration as a function of investigated species. Moreover, biomolecular effects on taxonomically different species are illustrated. In the final paragraph, main findings have been summarized and possible solutions to environmental threats posed by PFCs in the aquatic environment are discussed.

Evaluation of Cyto-genotoxicity of Perfluorooctane Sulfonate (PFOS) to Allium cepa

Per- and polyfluoroalkyl substances (PFAS) have emerged as contaminants of global concern. Among several PFAS, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are persistent and bioaccumulative compounds. We investigated the cyto-genotoxic potential of PFOS to Allium cepa root meristem cells. The A. cepa root tips were exposed to 6 different concentrations (1-100 mg L^-1 ) of PFOS for 48 h. Reduction in mitotic index and chromosomal aberrations was measured as genotoxic endpoints in meristematic root cells. Exposure to PFOS significantly affected cell division by reducing the miotic index at higher concentrations (>10 mg L^-1 ). The median effect concentration of PFOS to elicit cytotoxicity based on the mitotic index was 43.2 mg L^-1 . Exposure to PFOS significantly increased chromosomal aberrations at concentrations >25 mg L^-1 . The common aberrations were micronuclei, vagrant cells, and multipolar anaphase. The alkaline comet assay revealed a genotoxic potential of PFOS with increased tail DNA percentage at concentrations >25 mg L^-1 . To our knowledge, this is the first study to report the cyto-genotoxic potential of PFOS in higher plants. Environ Toxicol Chem 2021;40:792-798. © 2020 SETAC.

Risk Assessment of Per- and Polyfluoroalkyl Substance Mixtures: A Relative Potency Factor Approach

Per- and polyfluoroalkyl substances (PFAS) often occur together as contamination in exposure media such as drinking water or food. The relative potency factor (RPF) methodology facilitates the risk assessment of mixture exposure. A database of liver endpoints was established for 16 PFAS, using data with the same species (rat), sex (male), and exposure route (oral) and comparable exposure duration (42-90 d). Dose-response analysis was applied to derive the relative potencies of 3 perfluoroalkyl sulfonic acids (perfluorobutane sulfonic acid, perfluorohexane sulfonic acid, perfluorooctane sulfonic acid), 8 perfluoroalkyl carboxylic acids (perfluorobutanoic acid, perfluorohexanoic acid, perfluorononanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, perfluorotetradecanoic acid, perfluorohexadecanoic acid, perfluorooctadecanoic acid), 2 perfluoroalkyl ether carboxylic acids (tetrafluoro-2-[heptafluoropropoxy]propanoic acid, 3H-perfluoro-3-[(3-methoxy-propoxy)propanoic acid]), and 2 fluorotelomer alcohols (6:2 FTOH, 8:2 FTOH) compared to perfluorooctanoic acid (PFOA), based on liver effects. In addition, the RPFs of 7 other perfluoroalkyl acids were estimated based on read-across. This resulted in the relative potencies of 22 PFAS compared to the potency of index compound PFOA. The obtained RPFs can be applied to measured PFAS quantities, resulting in the sum of PFOA equivalents in a mixture. This sum can be compared with an established PFOA concentration limit (e.g., in drinking water or food) or an external health-based guidance value (e.g., tolerable daily intake, acceptable daily intake, or reference dose) to estimate the risk resulting from direct oral exposure to mixtures. Assessing mixture exposure is particularly relevant for PFAS, with omnipresent exposure in our daily lives. Environ Toxicol Chem 2021;40:859-870. © 2020 SETAC.

Transfer of Per- and Polyfluoroalkyl Substances (PFAS) from Feed into the Eggs of Laying Hens. Part 2: Toxicokinetic Results Including the Role of Precursors

A feeding study was performed to examine the bioaccumulation of per- and polyfluoroalkyl substances (PFAS) in laying hens' tissues and plasma and feed-to-egg transfer rates and half-lives. A 25 day exposure was followed by a 42 day depuration period. A target analysis revealed substantial amounts of the precursors N-methyl and N-ethyl perfluorooctane sulfonamidoacetic acid (Me- and EtFOSAA), perfluorooctane sulfonamidoacetic acid (FOSAA), and perfluorooctane sulfonamide (FOSA). In tissues and eggs, the highest bioaccumulation was found for PFHxS, PFHpS, PFOS, and PFOA. Low levels of PFHxS (all samples), PFOS, and FOSAA (in yolk) were measurable even after the depuration period. The egg elimination half-lives of PFOS and aforementioned precursors were estimated to be 4.3 days, while the transfer rates of PFOS and all precursors taken together were 0.99. The transfer rate of PFOA was around 0.49. PFHxS and PFHpS showed apparent transfer rates of >100%, which is hypothesized to indicate the presence of precursors.

Determination of organically bound fluorine sum parameters in river water samples-comparison of combustion ion chromatography (CIC) and high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS)

In this study, we compare combustion ion chromatography (CIC) and high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) with respect to their applicability for determining organically bound fluorine sum parameters. Extractable (EOF) and adsorbable (AOF) organically bound fluorine as well as total fluorine (TF) were measured in samples from river Spree in Berlin, Germany, to reveal the advantages and disadvantages of the two techniques used as well as the two established fluorine sum parameters AOF and EOF. TF concentrations determined via HR-CS-GFMAS and CIC were comparable between 148 and 270 μg/L. On average, AOF concentrations were higher than EOF concentrations, with AOF making up 0.14–0.81% of TF (determined using CIC) and EOF 0.04–0.28% of TF (determined using HR-CS-GFMAS). The results obtained by the two independent methods were in good agreement. It turned out that HR-CS-GFMAS is a more sensitive and precise method for fluorine analysis compared to CIC. EOF and AOF are comparable tools in risk evaluation for the emerging pollutants per- and polyfluorinated alkyl substances; however, EOF is much faster to conduct.

Perfluoroalkyl Substances in U.S. market basket fish and shellfish

Over the past two decades the class of per- and polyfluoroalkyl substances (PFAS) has emerged as a widespread contaminant in environmental media globally. As awareness and understanding of its prevalence, persistence, and potential health risks grows, so have concerns about human exposure. While drinking water has received substantial attention, dietary intakes have also been reported to contribute significantly to total exposure, with fish consumption in particular. Most studies of U.S. fish have targeted sport fish from areas of known or suspected contamination. This study was undertaken to improve data on PFAS levels in the U.S. commercial seafood supply. A total of 70 samples of finfish and shellfish were purchased at U.S. grocery stores and fish markets and analyzed for 26 PFAS compounds. The samples included a range of marine and freshwater species from four regions of the U.S. and seven countries with significant imports to the U.S. Up to ten PFAS were detected in 21 samples, with PFOS the predominant compound. There were no detections in the remaining 49 samples (detection limits of approximately 0.4-0.5 ppb). Total PFAS concentrations in most samples were single digit or sub-ppb levels. The exception was commercial finfish from the Great Lakes area, for which higher levels (up to 22 ppb) were observed in whitefish, walleye, and yellow perch fillet. Study findings suggest PFAS is present at low or non-detect levels in the U.S. commercial seafood supply and exposure is low for consumers of market basket fish and shellfish.

Per- and polyfluoroalkyl substances (PFASs) in blood of captive Siberian tigers in China: Occurrence and associations with biochemical parameters

Per- and polyfluoroalkyl substances (PFASs) have been ubiquitously detected in the environment and marine animals. However, little is known about these substances and their associations with health parameters in wild terrestrial mammals. In this study, we determined PFAS levels and distribution in the blood of captive Siberian tigers in Harbin, China, and evaluated potential exposure pathways by daily intake. In addition, for the first time, we explored the associations between serum PFAS concentrations and clinical parameters. Results showed that perfluorooctanoate (PFOA) was the dominant PFAS compound in blood (accounting for 64%), followed by perfluorooctanesulfonate (PFOS). In addition, 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) concentrations were also detected in blood and dietary food. Furthermore, significant positive age relationships were observed for levels of perfluoroheptanoate (PFHpA), PFOA, PFOS, and 6:2 Cl-PFESA in the blood of female tigers. Results showed that PFOA and PFOS in dietary food accounted for over 70% of total daily intake of PFASs, indicating that meat consumption is a predominant exposure pathway in tigers. We also found positive associations between higher exposure to PFASs (including PFOA, PFOS, and 6:2 Cl-PFESA) and elevated serum levels of alanine transaminase (ALT), a marker of liver damage. Thus, comprehensive health assessments of PFAS burdens in wildlife are needed.

Determination of perfluoroalkyl substances (PFASs) in fats and oils by QuEChERS/micro-HPLC-MS/MS

Per- and polyfluoroalkyl substances (PFASs) are man-made chemicals that have been identified as global pollutants. Their widespread occurrence, including in food, is a potential concern for consumers. This work focuses on the application of a simple and reliable analytical method for the simultaneous determination of ten perfluoroalkyl acids in highly complex fatty matrices (fats and oils). The perfluoroalkyl substances were extracted by the QuEChERS method, based on the dispersive-Solid Phase Extraction using styrene-divinylbenzene bulk sorbent, and quantitatively analysed by micro-high performance liquid chromatography tandem mass spectrometry. Recoveries ranged from 72 to 104% with an acceptable relative standard deviation below 10%. Limits of quantification were within the range 0.002-0.075 ng/g depending on the perfluoroalkyl compound. The most predominant compound in fat and oil food samples was perfluorooctanoic acid (PFOA) with a detection frequency of 100%, and the highest levels were found for perfluorobutanoic acid (PFBA). The estimated exposure to PFOA, which was 46% and 19% of the existing TWI for the EU and Polish population, respectively, is relatively high and indicates a potential risk to human health.

Polyfluoroalkyl substances in Danjiangkou Reservoir, China: Occurrence, composition, and source appointment

Legacy polyfluoroalkyl substances (PFASs) have been widely detected in various environmental matrices, which has caused great public concern. This study investigated the concentration, composition, partitioning, source apportionment, estimated daily intake (EDI), and ecological risks of 18 PFASs in water and sediments from Danjiangkou Reservoir. The total PFASs concentrations were 0.46-97.94 ng/L in water and 0.07-1.62 μg/kg in sediments. The total PFASs concentrations in water followed the order of spring > summer > winter > autumn (p < 0.05), and the PFAS compositions in water also varied among four seasons. However, no seasonal differences in the concentrations and compositions of PFASs were observed in sediments. The calculated logK_oc values of perfluoroalkyl carboxylic acids (PFCAs) were dependent on carbon chain length, decreasing first from C6 to C8 and then increasing from C8 to C13 due to the combined effects of steric hindrance and hydrophobic interaction, while the logK_oc values of C14 and C16 PFCAs were the lowest because of their very limited use. Principal component analysis-multiple linear regression analysis (PCA-MLRA) showed that food packaging/metal plating were the main sources of PFASs in spring, autumn, and winter, accounting for 64.8-81.9% and 50.5-76.9% of the total PFASs in water and sediments, respectively. However, in summer, 68.6% of total PFASs in water originated from leather/fabrics/textiles, and 70.0% of total PFASs in sediments were derived from textile treatment agents. The total EDI values through drinking water and dermal contact were 0.85, 0.69, 0.51, and 0.47 ng/kg bw/day for children (2-6, 7-12, and 13-17 years old) and adults, respectively, which were lower than the European Food Safety Authority's tolerable daily intake. However, the detected PFASs could pose low to medium ecological risks to daphnids and fish in spring. The study was significant for the development of effective strategies for controlling PFASs pollution in the Danjiangkou Reservoir.

Perfluoroalkyl Substances Stimulate Insulin Secretion by Islet β Cells via G Protein-Coupled Receptor 40

The potential causal relationship between exposure to environmental contaminants and diabetes is troubling. Exposure of perfluoroalkyl substances (PFASs) is found to be associated with hyperinsulinemia and the enhancement of insulin secretion by islet β cells in humans, but the underlying mechanism is still unclear. Here, by combining in vivo studies with both wild type and gene knockout mice and in vitro studies with mouse islet β cells (β-TC-6), we demonstrated clearly that 1 h exposure of perfluorooctanesulfonate (PFOS) stimulated insulin secretion and intracellular calcium level by activating G protein-coupled receptor 40 (GPR40), a vital free fatty acid regulated membrane receptor on islet β cells. We further showed that the observed effects of PFASs on the mouse model may also exist in humans by investigating the molecular binding interaction of PFASs with human GPR40. We thus provided evidence for a novel mechanism for how insulin-secretion is disrupted by PFASs in humans.

PFOS Modulates Interactive Epigenetic Regulation in First-Trimester Human Trophoblast Cell Line HTR-8/SVneo

Organic compounds have been linked to adverse pregnancy complications. Perfluorooctanesulfonic acid (PFOS), a man-made fluorosurfactant and global pollutant, has been shown to induce oxidative stress in various cell types. Oxidative stress plays a key role in leading several placental diseases including preeclampsia (PE), gestational diabetes, spontaneous abortion, preterm labor, and intrauterine growth restriction. Recently, epigenetic regulation such as histone modifications, DNA methylation, and microRNAs (miRNAs), are shown to be associated with oxidative stress as well as pregnancy complications such as PE. However, whether PFOS exerts its detrimental effects in the placenta through epigenetics remains to be unveiled. Therefore, we aimed to investigate the effect of PFOS-induced reactive oxygen species (ROS) generation in first trimester human trophoblast cell line (HTR-8/SV_neo) and whether epigenetic regulation is involved in this process. When treated with a range of PFOS doses at 24 and 48 h, even at 10 μM, it significantly increased the ROS production and decreased gene and protein expression, respectively, of the DNA methyltransferases DNMT1 (p < 0.001; p < 0.05), DNMT3A (p < 0.001; p < 0.05), and DNMT3B (p < 0.01; p < 0.01) and the sirtuins, for example, SIRT1 (p < 0.001; p < 0.001) and SIRT3 (p < 0.001; p < 0.05), while reducing global DNA methylation (p < 0.01) and increasing protein lysine acetylation (p < 0.001) as compared to vehicle controls. Interestingly, PFOS (10 μM) significantly increased miR29-b (p < 0.01), which has been previously reported to be associated with PE. The observed epigenetic effects were shown to be dependent on the expression of miR-29b, as knockdown of miR-29b significantly alters the gene and protein expression of DNMT1, DNMT3A, DNMT3B, SIRT1, and SIRT3 and ROS production as well as global DNA methylation and protein acetylation. This study provides for the first time a novel insight into PFOS-induced ROS generation via regulation of sets of the interactive epigenetic circuit in the placenta, which may lead to pregnancy complications.