Developmental toxicity of PFOS and PFOA in great cormorant (Phalacrocorax carbo sinensis), herring gull (Larus argentatus) and chicken (Gallus gallus domesticus)

Maternal transfer of per- and polyfluoroalkyl substances (PFAS) in wild birds: A systematic review and meta-analysis

Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals widely used in consumer products. PFAS can accumulate in animal tissues, resulting in biomagnification and adverse effects on wildlife, such as reproductive impairment. In bird species, PFAS are transferred from mothers to eggs along with essential nutrients and may affect embryo development. However, the extent of maternal PFAS transfer across different species and compounds remains poorly understood. Here, we conducted a systematic review and meta-analysis to quantify maternal PFAS transfer in wild birds and investigate potential sources of variation. We tested the moderating effects of compounds' physicochemical properties and biological traits of studied birds. The dataset included 505 measurements of PFAS concentration and 371 effect sizes derived from 13 studies on 16 bird species and 25 compounds. Overall, across all studies and species, we found a 41% higher concentration of PFAS in offspring than in mothers. Specifically, contaminants were concentrated in the yolk, longer and heavier compounds showed preferential transfer, larger clutch size was associated with decreased PFAS transfer and a higher transfer rate was shown in species with piscivorous and opportunistic/diverse diets. A validation assessment showed good robustness of the overall meta-analytic result. Given the crucial role of birds in maintaining ecological balance, this research article has relevant implications for modelling the impacts of PFAS on wildlife, ecosystems, and human health.

A decade of data and hundreds of analytes: Legacy and emerging chemicals in North American herring gull plasma

Between 2010 and 2021, 199 herring gull serum samples were collected from Lake Michigan, Lake Huron, and Lake Erie, including two Areas of Concern: Saginaw Bay and the River Raisin. They were analyzed for 21 polybrominated diphenyl ether congeners, 10 non-PBDE flame retardants, 85 polychlorinated biphenyls, 17 legacy organochlorine pesticides, and 36 per- and polyfluoroalkyl substances. Σ36PFAS, Σ85PCB, Σ21PBDE, and Σ17Pesticide concentrations comprised 41-74%, 17-50%, 3-4%, and 5-9% of the total concentration, respectively. Median concentrations of the chemical groups ranged from 81.5 to 129 ng/g ww for PFAS, 26.3-158 ng/g ww for PCBs, 4.26-8.89 ng/g ww for PBDEs, and 8.08-23.0 ng/g ww for pesticides. The regional concentrations of all four classes of compounds are significantly decreasing when sites are combined with halving times of 11.3 ± 4.8, 8.2 ± 4.3, 5.9 ± 3.1, and 8.3 ± 4.2 years for the Penta-BDE mixture, ΣDDTs, Σ85PCBs and Σ36PFAS, respectively. These results suggest that, while PFAS has emerged as the dominant group of chemicals in the plasma, legacy pollutants continue to represent a threat to herring gulls and wildlife in the Great Lakes basin. PCBs were the largest contributors to the chemical load in plasma of birds whose colonies are located near the River Raisin, and continue to pose a threat to herring gulls within the two Areas of Concern.

Per- and polyfluoroalkyl substances (PFAS) in little penguins and associations with urbanisation and health parameters

Per- and Polyfluoroalkyl substances (PFAS) are increasingly detected in wildlife and present concerning and unknown health risks. While there is a growing body of literature describing PFAS in seabird species, knowledge from temperate Southern Hemisphere regions is lacking. Little penguins (Eudyptula minor) can nest and forage within heavily urbanised coastal environments and hence may be at risk of exposure to pollutants. We analysed scat contaminated nesting soils (n = 50) from 17 colonies in lutruwita/Tasmania for 16 PFAS, plasma samples (n = 45) from nine colonies, and three eggs for 49 PFAS. We detected 14 PFAS across the sample types, with perfluorooctanesulfonic acid (PFOS) and perfluorohexanesulfonic acid (PFHxS) most commonly detected. Mean concentration of PFOS in plasma was 2.56 ± 4.3 ng/mL ( Collapse

Key Words

• Ecotoxicology
• Genotoxicity
• Human impacts
• Seabird sentinels
• Wildlife health

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MESH Headings

• Male
• Female
• Animals
• Spheniscidae
• Urbanization
• Alkanesulfonic Acids/analysis
• Environmental Pollutants/analysis
• Fluorocarbons/analysis
• Soil
• Sulfonic Acids

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Affiliation(s)

Melanie R Wells Department of Biological Sciences, School of Natural Sciences, University of Tasmania, Hobart 7001, Tasmania, Australia; Institute for Marine and Antarctic Studies, Battery Point 7004, Tasmania, Australia.
Timothy L Coggan Environment Protection Authority Victoria, 200 Victoria Street, Carlton 3053, Victoria, Australia; ADE Consulting Group, U 4/95 Salmon Street, Port Melbourne 3207, Victoria, Australia
Gavin Stevenson Australian Ultra-Trace Laboratory, National Measurement Institute, North Ryde 2113, New South Wales, Australia
Navneet Singh ADE Consulting Group, U 4/95 Salmon Street, Port Melbourne 3207, Victoria, Australia
Matthew Askeland ADE Consulting Group, U 4/95 Salmon Street, Port Melbourne 3207, Victoria, Australia
Mary-Anne Lea Institute for Marine and Antarctic Studies, Battery Point 7004, Tasmania, Australia; Centre for Marine Socioecology, University of Tasmania, Hobart 7001, Tasmania, Australia
Annie Philips Wildlife Veterinary Consultant, Hobart 7000, Tasmania, Australia
Scott Carver Department of Biological Sciences, School of Natural Sciences, University of Tasmania, Hobart 7001, Tasmania, Australia; Odum School of Ecology, University of Georgia, GA, USA 30602; Center for the Ecology of Infectious Diseases, University of Georgia, GA, USA 30602

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Assessment of perfluoroalkyl substances concentration levels in wild bat guano samples

Perfluoroalkyl substances (PFASs) are substances commonly used in the production of various everyday objects, including among others kitchen dishes, cosmetics, or clothes. They penetrate to the environment and living organisms causing disturbances in the functioning of many internal organs and systems. Due to environmental pollution, wildlife is also exposed to PFASs, but the knowledge about this issue is rather limited. The aim of this study was to evaluate the exposure of wild greater mouse-eared bats (Myotis myotis), living in Poland, to six selected PFASs: five perfluoroalkyl carboxylic acids (perfluorobutanoic acid-PFBuA, perfluoropentanoic acid-PFPeA, perfluorohexanoic acid-PFHxA, perfluoroheptanoic acid-PFHpA, perfluorooctanoic acid-PFOA) and perfluorooctane sulfonic acid (PFOS) through the analysis of guano samples with liquid chromatography with tandem mass spectrometry (LC-MS-MS) method. To our knowledge this is the first study concerning the PFASs levels in bats, as well as using guano samples to evaluate the exposure of wild mammals to these substances. A total of 40 guano samples were collected from 4 bats summer (nursery) colonies located in various parts of Poland. The presence of PFASs mentioned were detected in all colonies studied, and concentration levels of these substances were sampling dependent. The highest concentration levels were observed in the case of PFPeA [1.34 and 3060 ng/g dry weight (dw)] and PFHxA (8.30-314 ng/g dw). This study confirms the exposure of wild bats to PFASs.

Contaminant biomonitoring augmented with a qPCR array indicates hepatic mRNA gene expression effects in wild-collected seabird embryos

Birds can bioaccumulate persistent contaminants, and maternal transfer to eggs may expose embryos to concentrations sufficient to cause adverse effects during sensitive early-life stages. However, using tissue residue concentrations alone to infer whether contaminant effects are occurring suffers from uncertainty, and efficient, sensitive biomarkers remain limited in wildlife. We studied relationships between whole embryo contaminant concentrations (total mercury, organochlorine pesticides, perfluoroalkyl substances, polychlorinated biphenyls, and halogenated flame retardants) together with mRNA expression in embryonic liver tissue from a Pacific Ocean seabird, the rhinoceros auklet (Cerorhinca monocerata). Fresh eggs were collected, incubated under controlled conditions, and from the pre-hatch embryo, hepatic RNA was extracted for qPCR array analysis to measure gene expression (2-∆Cq), while the remaining embryo was analyzed for contaminant residues. Contaminant and gene expression data were assessed with a combination of multivariate approaches and linear models. Results indicated correlations between embryonic total mercury and several genes such as sepp1, which encodes selenoprotein P. Correlation between the biotransformation gene cyp1a4 and the C7 perfluoroalkyl carboxylic acid PFHpA was also evident. This study demonstrates that egg collection from free-living populations for contaminant biomonitoring programs can relate chemical residues to in ovo mRNA gene expression effects in embryo hepatic tissue.

Per- and polyfluoroalkyl substances (PFAS) contamination in a microtidal urban estuary: Sources and sinks

This study evaluates PFAS contamination and determines the major drainage sources to a temperate microtidal estuary, the Swan Canning Estuary, in Perth Western Australia. We describe how variability in these sources influences PFAS concentrations within this urban estuary. Surface water samples were collected from 20 estuary sites and 32 catchment sites in June and December from 2016 to 2018. Modelled catchment discharge was used to estimate PFAS load over the study period. Three major catchment sources of elevated PFAS were identified with contamination likely resulting from historical AFFF use on a commercial airport and defence base. Estuary PFAS concentration and composition varied significantly with season and spatially with the two different estuary arms responding differently to winter and summer conditions. This study has found that the influence of multiple PFAS sources on an estuary depend on the historical usage timeframe, groundwater interactions and surface water discharge.

Large-scale assessment of exposure to legacy and emerging per- and polyfluoroalkyl substances in China's shorebirds

Emerging per- and polyfluoroalkyl substances (PFAS) have become more widely applied, whereas legacy PFAS such as PFOS continue to distribute ubiquitously in the environment. Large-scale assessment of wildlife exposure to both emerging and legacy PFAS plays a key role in effective biomonitoring to better discriminate regional contamination patterns and provide early warnings. Using eggs of two closely-related shorebird species collected across China during the breeding season in 2021, we constructed contrasting PFAS levels and profiles in coastal versus inland populations. The highest ∑PFAS concentrations were found in two Kentish plover (Charadrius alexandrinus) populations from the Bohai Sea, a semi-enclosed shallow bay located in northeast China. These two populations showed exceptionally high PFOA concentrations (mean: 94 and 121 ng/g wet weight; West and North Bohai Sea, respectively) dominating the overall PFAS profile (66% for both). This pattern is characteristic, compared to that of other seabird eggs worldwide. By comparison, PFAS profile in the white-faced plover (Charadrius dealbatus) population at the South China Sea coast was dominated by PFOS (46%), which showed similar levels to those at the North Bohai Sea coast (mean: 29 and 20 ng/g, respectively). PFAS concentrations of Kentish plovers from the remote Qinghai Lake were lower compared to the three coastal populations, and were dominated by PFNA (mean: 2.6 ng/g, 29%) and PFOS (mean: 2.5 ng/g, 27%). None of the eggs analyzed in the present study exceeded estimated toxicity reference values for PFOS or PFOA. Additionally, the emerging 6:2 Cl-PFESA was detected in eggs from all regions, while its concentrations were highest in the Bohai Sea populations, and short-chain PFBS was only detected in the North Bohai Sea population. Our results indicate intensive local emissions of PFOA and emerging PFAS at the Bohai Sea region, and warrant further investigation and monitoring.

Global ocean contamination of per- and polyfluoroalkyl substances: A review of seabird exposure

Per- and polyfluoroalkyl substances (PFAS) have been extensively produced and used as surfactants and repellents for decades. To date, the global contamination pattern of PFAS in marine biota has seldomly been reviewed. Seabirds are ideal biomonitoring tools to study environmental contaminants and their effects. Here, we compiled and synthesized reported PFAS concentrations in various seabird species to reflect spatiotemporal patterns and exposure risks of major PFAS on a global ocean scale. Perfluorooctane sulfonic acid (PFOS) was the most studied PFAS in seabirds, which showed the highest level in eggs of common guillemots (U. aalge) from the Baltic Sea, followed by great cormorants (P. carbo) from the North Sea and double-crested cormorants (P.auritus) from the San Francisco Bay, whereas the lowest were those reported for Antarctic seabirds. The temporal pattern showed an overall higher level of PFOS in the late 1990s and early 2000s, consistent with the phase-out of perfluorooctane sulfonyl fluoride-based products. Maximum liver PFOS concentrations in several species such as cormorants and fulmars from Europe and North America exceeded the estimated toxicity reference values. Systematic evaluations using representative species and long time-series are necessary to understand contamination patterns in seabirds in South America, Africa, and Asia where information is lacking. In addition, limited research has been conducted on the identification and toxic effects of novel substitutes such as fluorotelomers and ether PFAS (F-53B, Gen-X etc.) in seabirds. Further research, including multi-omics analysis, is needed to comprehensively characterize the exposure and toxicological profiles of PFAS in seabirds and other wildlife.

A Bad Start in Life? Maternal Transfer of Legacy and Emerging Poly- and Perfluoroalkyl Substances to Eggs in an Arctic Seabird

In birds, maternal transfer is a major exposure route for several contaminants, including poly- and perfluoroalkyl substances (PFAS). Little is known, however, about the extent of the transfer of the different PFAS compounds to the eggs, especially for alternative fluorinated compounds. In the present study, we measured legacy and emerging PFAS, including Gen-X, ADONA, and F-53B, in the plasma of prelaying black-legged kittiwake females breeding in Svalbard and the yolk of their eggs. We aimed to (1) describe the contaminant levels and patterns in both females and eggs, and (2) investigate the maternal transfer, that is, biological variables and the relationship between the females and their eggs for each compound. Contamination of both females and eggs were dominated by linPFOS then PFUnA or PFTriA. We notably found 7:3 fluorotelomer carboxylic acid─a precursor of long-chain carboxylates─in 84% of the egg yolks, and provide the first documented finding of ADONA in wildlife. Emerging compounds were all below the detection limit in female plasma. There was a linear association between females and eggs for most of the PFAS. Analyses of maternal transfer ratios in females and eggs suggest that the transfer is increasing with PFAS carbon chain length, therefore the longest chain perfluoroalkyl carboxylic acids (PFCAs) were preferentially transferred to the eggs. The mean ∑_PFAS in the second-laid eggs was 73% of that in the first-laid eggs. Additional effort on assessing the outcome of maternal transfers on avian development physiology is essential, especially for PFCAs and emerging fluorinated compounds which are under-represented in experimental studies.

Occurrence, profiles, and ecotoxicity of poly- and perfluoroalkyl substances and their alternatives in global apex predators: A critical review

Certain poly- and perfluoroalkyl substances (PFASs) exhibit significant bioaccumulation/biomagnification behaviors in ecosystems. PFASs, such as perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonic acid (PFHxS) and related precursors, have elicited attention from both public and national regulatory agencies, which has resulted in worldwide restrictions on their production and use. Apex predators occupy the top trophic positions in ecosystems and are most affected by the biomagnification behavior of PFASs. Meanwhile, the long lifespans of apex predators also lead to the high body burden of PFASs. The high body burden of PFASs might be linked to adverse health effects and even pose a potential threat to their reproduction. As seen in previous reviews of PFASs, knowledge is lacking between the current stage of the PFAS body burden and related effects in apex predators. This review summarized PFAS occurrence in global apex predators, including information on the geographic distribution, levels, profiles, and tissue distribution, and discussed the trophic transfer and ecotoxicity of PFASs. In the case where legacy PFASs were restricted under international convention, the occurrence of novel PFASs, such as 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) and perfluoroethylcyclohexane sulfonate (PFECHS), in apex predators arose as an emerging issue. Future studies should develop an effective analytical method and focus on the toxicity and trophic transfer behavior of novel PFASs.

Immunometabolism-modulation and immunotoxicity evaluation of perfluorooctanoic acid in macrophage

Perfluorooctanoic acid (PFOA) is one of the most commonly used perfluorinated chemicals in industry. Wide concerns of PFOA toxicity are increased in recent years. However, report on immunotoxicity of PFOA was quite limited. This study aimed to investigate the immunotoxicity of PFOA exposure on macrophage RAW264.7. We assessed the effects of PFOA exposure on macrophage cell viability, cell apoptosis and cellular ROS level, and detected prominent cytokines release by RAW264.7. The results indicated that the cell viability of macrophage RAW264.7 was decreased by PFOA in dose- and time-dependent manners. Specifically, the exposure of 200 μM PFOA significantly increased apoptosis and ROS generation in macrophage, and thus caused cell damage. The ELISA results displayed that 100 μM PFOA exposure induced macrophage activation and enhanced cytokines secretion, including TNF-α, IL-1, IL-6, and IL-12. We also conducted nontargeted metabolomics based on LC-MS/MS and unveiled the perturbed metabolic pathways in macrophages induced by sublethal doses of PFOA (10 μM and 100 μM). Remarkably, global metabolomics results displayed that 10 μM PFOA exposure affected glutamine related pathways and the exposure at 100 μM conspicuously changed glutathione and fatty acid oxidation metabolism. These findings showed that 10 μM PFOA exposure could impel metabolic reprogramming of macrophage to trigger inflammatory response, although such dose displayed no obvious effect on cell viability, cellular ROS or apoptosis events of macrophage RAW264.7.

Assessing the Ecological Risks of Per- and Polyfluoroalkyl Substances: Current State-of-the Science and a Proposed Path Forward

Per- and poly-fluoroalkyl substances (PFAS) encompass a large, heterogenous group of chemicals of potential concern to human health and the environment. Based on information for a few relatively well-understood PFAS such as perfluorooctane sulfonate and perfluorooctanoate, there is ample basis to suspect that at least a subset can be considered persistent, bioaccumulative, and/or toxic. However, data suitable for determining risks in either prospective or retrospective assessments are lacking for the majority of PFAS. In August 2019, the Society of Environmental Toxicology and Chemistry sponsored a workshop that focused on the state-of-the-science supporting risk assessment of PFAS. The present review summarizes discussions concerning the ecotoxicology and ecological risks of PFAS. First, we summarize currently available information relevant to problem formulation/prioritization, exposure, and hazard/effects of PFAS in the context of regulatory and ecological risk assessment activities from around the world. We then describe critical gaps and uncertainties relative to ecological risk assessments for PFAS and propose approaches to address these needs. Recommendations include the development of more comprehensive monitoring programs to support exposure assessment, an emphasis on research to support the formulation of predictive models for bioaccumulation, and the development of in silico, in vitro, and in vivo methods to efficiently assess biological effects for potentially sensitive species/endpoints. Addressing needs associated with assessing the ecological risk of PFAS will require cross-disciplinary approaches that employ both conventional and new methods in an integrated, resource-effective manner. Environ Toxicol Chem 2021;40:564-605. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

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.

Effects on Apical Outcomes of Regulatory Relevance of Early-Life Stage Exposure of Double-Crested Cormorant Embryos to 4 Environmental Chemicals

Environmental risk assessment is often challenged by a lack of toxicity data for ecological species. The overall goal of the present study was to employ an avian early-life stage toxicity test to determine the effects of 4 chemicals (benzo[a]pyrene [BaP], chlorpyrifos, fluoxetine hydrochloride [FLX], and ethinyl estradiol [EE2]) on an ecologically relevant avian species, the double-crested cormorant (Phalacrocorax auritus), and to compare our results with those we previously reported for a laboratory model species, Japanese quail. Chemicals were dissolved in dimethyl sulfoxide and administered via air cell injection to fertilized, unincubated double-crested cormorant eggs at 3 nominal concentrations, the highest selected to approximate the 20% lethal dose. Of the 4 chemicals, only chlorpyrifos and FLX were detected in liver tissue of embryos at midincubation (day 14) and termination (day 26; 1-2 d prior to hatch); EE2 and BaP were not detectable, suggesting embryonic clearance/metabolism. No apical effects were observed in double-crested cormorant embryos up to the highest concentrations of chlorpyrifos (no-observed-effect level [NOEL] = 25 µg/g) or FLX (NOEL = 18 µg/g). Exposure to EE2 reduced embryonic viability and increased deformities at a concentration of 2.3 µg/g (NOEL = 0.18 µg/g), and BaP decreased embryonic viability (median lethal dose = 0.015 µg/g; NOEL = 0.0027 µg/g). Compared with Japanese quail, double-crested cormorant were more sensitive with regard to embryolethality and deformities for EE2 and embryolethality for BaP, whereas they were less sensitive to embryonic deformities associated with chlorpyrifos exposure. These data reinforce the idea that standardized toxicity tests using a laboratory model species may not always be protective of wild birds, and thus they stress the importance of developing such alternative testing strategies (e.g., the EcoToxChip Project) for ecologically relevant species to augment risk assessment efforts. Environ Toxicol Chem 2021;40:390-401. © 2020 SETAC.

Contrasting long term temporal trends in perfluoroalkyl substances (PFAS) in eggs of the northern gannet (Morus bassanus) from two UK colonies

We compared long-term (1977 to 2014) trends in concentrations of PFAS in eggs of the marine sentinel species, the Northern gannet (Morus bassanus), from the Irish Sea (Ailsa Craig) and the North Sea (Bass Rock). Concentrations of eight perfluorinated carboxylic acids (PFCAs) and three perfluorinated sulfonates (PFSAs) were determined and we report the first dataset on PFAS in UK seabirds before and after the PFOS ban. There were no significant differences in ∑PFAS or ∑PFSAs between both colonies. The ∑PFSAs dominated the PFAS profile (>80%); PFOS accounted for the majority of the PFSAs (98-99%). In contrast, ∑PFCAs concentrations were slightly but significantly higher in eggs from Ailsa Craig than in those from Bass Rock. The most abundant PFCAs were perfluorotridecanoate (PFTriDA) and perfluoroundecanoate (PFUnA) which, together with PFOA, comprised around 90% of the ∑PFCAs. The ∑PFSAs and ∑PFCAs had very different temporal trends. ∑PFSAs concentrations in eggs from both colonies increased significantly in the earlier part of the study but later declined significantly, demonstrating the effectiveness of the phasing out of PFOS production in the 2000s. In contrast, ∑PFCAs concentrations in eggs were constant and low in the 1970s and 1980s, suggesting minimal environmental contamination, but residues subsequently increased significantly in both colonies until the end of the study. This increase appeared driven by rises in long chain compounds, namely the odd chain numbered PFTriDA and PFUnA. PFOA, had a very different temporal trend from the other dominant acids, with an earlier rise in concentrations followed by a decline in the last 15 years in Ailsa Craig; later temporal trends in Bass Rock eggs were unclear. Although eggs from both colonies contained relatively low concentrations of PFAS, the majority had PFOS residues that exceeded a suggested Predicted No Effect Concentration and ~ 10% of the eggs exceeded a suggested Lowest-Observable-Adverse-Effect.

Legacy and Novel Per- and Polyfluoroalkyl Substances in Juvenile Seabirds from the U.S. Atlantic Coast

Per- and polyfluoroalkyl substances (PFAS) are anthropogenic, globally distributed chemicals. Legacy PFAS, including perfluorooctane sulfonate (PFOS), have been regularly detected in marine fauna but little is known about their current levels or the presence of novel PFAS in seabirds. We measured 36 emerging and legacy PFAS in livers from 31 juvenile seabirds from Massachusetts Bay, Narragansett Bay, and the Cape Fear River Estuary (CFRE), United States. PFOS was the major legacy perfluoroalkyl acid present, making up 58% of concentrations observed across all habitats (range: 11-280 ng/g). Novel PFAS were confirmed in chicks hatched downstream of a fluoropolymer production site in the CFRE: a perfluorinated ether sulfonic acid (Nafion byproduct 2; range: 1-110 ng/g) and two perfluorinated ether carboxylic acids (PFO4DA and PFO5DoDA; PFO5DoDA range: 5-30 ng/g). PFOS was inversely associated with phospholipid content in livers from CFRE and Massachusetts Bay individuals, while δ 13C, an indicator of marine versus terrestrial foraging, was positively correlated with some long-chain PFAS in CFRE chick livers. There is also an indication that seabird phospholipid dynamics are negatively impacted by PFAS, which should be further explored given the importance of lipids for seabirds.

Novel and legacy per- and polyfluoroalkyl substances in bald eagle eggs from the Great Lakes region

Decades of large-scale production of per- and polyfluoroalkyl substances (PFASs) have resulted in their ubiquitous presence in the environment worldwide. Similarly to other persistent and bioaccumulative organic contaminants, some PFASs, particularly the long-chain congeners, can be biomagnified via food webs, making top predators vulnerable to elevated PFAS exposure. In this study, we measured seven classes of PFASs in bald eagle (Haliaeetus leucocephalus) eggs for the first time. The eggs (n = 22) were collected from the North American Great Lakes in 2000-2012. The ranges of total concentrations of perfluoroalkyl sulfonic acids (∑PFSAs) and perfluoroalkyl carboxylic acids (∑PFCAs) were 30.5-1650 and 5.4-216 ng/g wet weight (ww), respectively. In addition to these traditional PFAS compounds, 6:2 fluorotelomer sulfonic acid (6:2 FTS; median: 15.7 ng/g ww), perfluoro-4-ethylcyclohexanesulfonic acid (PFECHS; 0.22 ng/g ww), and 8-chloro-perfluorooctanesulfonic acid (Cl-PFOS, detected in wildlife for the first time; 0.53 ng/g ww) were also frequently detected. Bald eagle eggs from breeding areas located less than 8 km from a Great Lake shoreline or tributary had significantly greater total PFAS concentrations (∑PFASs) than those from breeding areas located further than 8 km (p < 0.05). In these samples, ∑PFASs rivalled the total concentration of brominated flame retardants, and were significantly greater than those of several other organic contaminants, such as dechlorane-related compounds, organophosphate esters, and flame retardant metabolites.

Perfluorooctanoic acid (PFOA) exposure inhibits DNA methyltransferase activities and alters constitutive heterochromatin organization

Perfluorooctanoic acid (PFOA) is a persistent and widespread industry-made chemical. Emerging evidence indicates that PFOA exposure could be meditated through DNA methylation, yet, the molecular mechanisms governing the epigenetic states have not been well established. In this study, we investigated the epigenetic alterations and inhibitory mechanisms upon PFOA exposure by identifying changes related to DNA methyltransferase (DNMT) with fluorescence correlation spectroscopy and stimulated emission depletion nanoscopy in human breast epithelial cells (MCF7). PFOA exposure at 100 and 200 μM altered the mobility of DNMT3A and inhibited the enzymatic activity of DNMT, resulting in global DNA demethylation. Moreover, PFOA significantly altered the heterochromatin organization, as noted by the distribution profile of histone 3 lysine 9 tri-methylation (H3K9me3) at 200 and 400 μM exposure levels with super-resolution microscopy. An increased redistribution around the periphery of the nucleus was noted with a more diffused distribution beyond the 200 μM exposure. Overall, exposure of PFOA resulted in DNA demethylation accompanied by altered expression patterns of DNMT1 and DNMT3A. These findings provided new insights on the epigenetic alterations and revealed an altered heterochromatin packaging upon exposure to PFOA, implicating a mechanistic mode of action of DNA demethylation through direct impacts on DNMTs and increasing susceptibility to diseases such as cancer.

Effects of chloride on electrochemical degradation of perfluorooctanesulfonate by Magnéli phase Ti4O7 and boron doped diamond anodes

This study examined the degradation of perfluorooctanesulfonate (PFOS) in an electrochemical system using Magnéli phase titanium suboxide (Ti₄O₇) as the anode. In particular, the influence of chloride on the treatment process was examined. Tests were also conducted with boron doped diamond (BDD) electrodes for comparison. Experimental data demonstrated that PFOS was effectively degraded by electrochemical oxidation on both BDD and Magnéli phase Ti₄O₇ anodes. It appeared that PFOS degradation occurred via direct electron transfer (DET) in combination with attack by hydroxyl radicals adsorbed on the anode surface (HO^•_ads) that were formed by anodic oxidation of water. The presence of Cl^- inhibited the degradation of the PFOS on Ti₄O₇ electrode by suppressing the oxidation of water, but accelerated PFOS degradation on BDD electrode, where the oxidation of Cl^- via DET occurred. Formation of chlorate and perchlorate was slower on Ti₄O₇ than on the BDD anode. The mechanisms governing the behavior of PFOS and chloride reactions on BDD and Ti₄O₇ anodes were explored by experiments in combination with density functional theory (DFT) computations.

Occurrence and distribution of perfluoroalkyl substances in surface riverine and coastal sediments from the Beibu Gulf, south China

There is limited understanding on the occurrence of PFASs in coastal sediment, especially in less-developed coastal areas. Here, we collected surface sediment samples from the Beibu Gulf to investigate the occurrence, spatial distribution and environmental risks of 18 PFASs. The concentrations of the total PFASs (ΣPFASs) ranged from 56.2 to 586.3 pg/g dry weight (dw), with a mean value of 172.5 pg/g dw. ΣPFASs concentrations were significantly lower in riverine than in coastal sediments. Additionally, there was a decreasing trend in ΣPFASs concentrations from the west (Fangchenggang) to the east (Beihai) of the Beibu Gulf. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) were the predominant PFASs, with their concentrations in the range of 4.8-249.0 pg/g dw and not detected (n.d)-224.8 pg/g dw, respectively. On a global scale, PFOS and PFOA concentrations were at low levels in the sediment of the Beibu Gulf, and they posed negligible environmental risks.

Negligible effects of TiO2 nanoparticles at environmentally relevant concentrations on the translocation and accumulation of perfluorooctanoic acid and perfluorooctanesulfonate in hydroponically grown pumpkin seedlings (Cucurbita maxima × C. moschata)

Titanium dioxide nanoparticles (TiO₂-NPs) are widely distributed in the environment. It has been demonstrated that TiO₂-NPs could modify the environmental fate and bioavailability of organic pollutants, which affects ecological risks of TiO₂-NPs and organic pollutants. In this study, the uptake, translocation and accumulation of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) in pumpkin plants was investigated in the presence of TiO₂-NPs. We reported for the first time the negligible effects of TiO₂-NPs at environmentally relevant concentrations (0.05-5 mg/L) on the uptake and accumulation of PFOA and PFOS in hydroponically grown pumpkin seedlings regardless of root, stem and leaf. This phenomenon was independent of the initial concentrations of PFOA/PFOS and TiO₂-NPs in the exposure solution. Also, seedling mass and contents of chlorophyll and anthocyanin were not affected by the co-exposure. Adsorption tests demonstrated the negligible adsorption of PFOA/PFOS on TiO₂-NPs in the exposure solution. Moreover, uptake of PFOA/PFOS was insensitive to aquaporin inhibitor AgNO₃ but significantly inhibited by niflumic acid (anion channel blocker) and 2,4-dinitrophenol (metabolic inhibitor) whereas Ti concentration in root was not affected by niflumic acid and 2,4-dinitrophenol but significantly decreased by AgNO₃, indicating that transport of PFOA/PFOS and TiO₂-NPs were via different routes into the pumpkin seedling. It was proposed that different pathways by which TiO₂-NPs and PFOA/PFOS transported into the pumpkin seedling and negligible adsorption of PFOA/PFOS on TiO₂-NPs contributed to the negligible effects of TiO₂-NPs on the uptake, translocation and accumulation of PFOA/PFOS in pumpkin seedlings. In total, this work would improve our understanding of the ecological risks of TiO₂-NPs in the environment.

Perfluorooctanoic acid-induced toxicities in chicken embryo primary cardiomyocytes: Roles of PPAR alpha and Wnt5a/Frizzled2

Perfluorooctanoic acid (PFOA) is a widespread persistent organic pollutant and may induce developmental toxicities, including developmental cardiotoxicity. To explore the potential mechanism of developmental cardiotoxicity induced by PFOA exposure, chicken embryo primary cardiomyocytes were extracted either from chicken embryos pretreated with PFOA (2 mg/kg), or from untreated embryos and then directly exposed cells to PFOA (1, 10, 30 or 100 μg/ml) in culture. Additionally, peroxisome proliferator activated receptor alpha (PPAR alpha) silencing lentivirus was applied to the embryos on embryonic day (ED2). Cell viability was measured with CCK-8 kit, morphology was assessed with hematoxylin and eosin staining, and intracellular Ca²⁺ concentrations were determined with Fluo-4 AM probe. Western blotting was utilized to confirm PPAR alpha silencing efficiency and the protein abundance of Wnt5a and Frizzled2. The results indicated that both PFOA pretreatment and direct exposure decreased primary cardiomyocyte viability, altered cell morphology and increased intracellular Ca²⁺ concentrations. While l-carnitine co-treatment effectively abolished such changes, PPAR alpha silencing only abolished most of the changes in PFOA pretreatment group, but not in cells directly exposed to relatively high doses of PFOA. The protein abundance of Wnt5a and Frizzled2 was increased by PFOA pretreatment, while direct exposure to PFOA increased Frizzled2 abundance but decreased Wnt5a abundance. PPAR alpha silencing resulted in over 50% decrease of PPAR alpha expression level, which abolished the Wnt5a/Frizzled2 expression alterations following PFOA exposure. In conclusion, PFOA-induced primary cardiomyocyte toxicity is associated with PPAR alpha and Wnt5a/Frizzled2, in which PPAR alpha seems to play regulatory roles towards Wnt5a/Frizzled2.

A proof of concept study demonstrating that environmental levels of carbamazepine impair early stages of chick embryonic development

Carbamazepine (CBZ) is an anticonvulsant drug used for epilepsy and other disorders. Prescription of CBZ during pregnancy increases the risk for congenital malformations. CBZ is ubiquitous in effluents and persistent during wastewater treatment. Thus, it is re-introduced into agricultural ecosystems upon irrigation with reclaimed wastewater. People consuming produce irrigated with reclaimed wastewater were found to be exposed to CBZ. However, environmental concentrations of CBZ (μgL^-1) are magnitudes lower than its therapeutic levels (μgml^-1), raising the question of whether and how environmental levels of CBZ affect embryonic development. The chick embryo is a powerful and highly sensitive amniotic model system that enables to assess environmental contaminants in the living organism. Since the chick embryonic development is highly similar to mammalians, yet, it develops in an egg, toxic effects can be directly analyzed in a well-controlled system without maternal influences. This research utilized the chick embryo to test whether CBZ is embryo-toxic by using morphological, cellular, molecular and imaging strategies. Three key embryonic stages were monitored: after blastulation (st.1HH), gastrulation/neurulation (st.8HH) and organogenesis (st.15HH). Here we demonstrate that environmental relevant concentrations of CBZ impair morphogenesis in a dose- and stage- dependent manner. Effects on gastrulation, neural tube closure, differentiation and proliferation were exhibited in early stages by exposing embryos to CBZ dose as low as 0.1μgL^-1. Quantification of developmental progression revealed a significant difference in the total score obtained by CBZ-treated embryos compared to controls (up to 5-fold difference, p<0.05). Yet, defects were unnoticed as embryos passed gastrulation/neurulation. This study provides the first evidence for teratogenic effect of environmental-relevant concentrations of CBZ in amniotic embryos that impair early but not late stages of development. These findings call for in-depth risk analysis to ensure that the environmental presence of CBZ and other drugs is not causing irreversible ecological and public-health damages.

Per- and polyfluoroalkyl substances in two different populations of northern cardinals

The northern cardinal (Cardinalis cardinalis) is a good indicator species for environmental contaminants because it does not migrate and its range covers a diversity of habitats, including metropolitan Atlanta, GA and the geographically isolated Hawaiian Islands. In addition, the cardinal is often found near people's homes, making it likely to be exposed to the same outdoor elements, including soil, groundwater, and air, that surrounding humans experience. In this study, blood serum concentrations of 12 per- and polyfluoroalkyl substances (PFASs) were measured in 40 cardinals from Atlanta and 17 cardinals from the Big Island (Hawaii), HI. We observed significantly higher median concentrations of four PFASs and significantly higher detection frequencies of seven PFASs in the cardinals from Atlanta, relative to the PFAS median concentrations and detection frequencies observed in the cardinals from Hawaii (α = 0.05). Among the PFASs measured, perfluorooctane sulfonate (PFOS) was observed in the highest concentrations. A linear regression model controlling for sex, age, and airport distance did not explain PFOS variation within the Atlanta samples, but a similar model explained 90% of PFOS variation within the Hawaii samples. To our knowledge, these are the first measurements of PFASs in northern cardinals.

Limited reproductive impairment in a passerine bird species exposed along a perfluoroalkyl acid (PFAA) pollution gradient

Although bird eggs have been used in biomonitoring studies on perfluoroalkyl acids (PFAAs), effects of environmental concentrations on reproduction remain largely unknown in wild birds. In the present study we examined the associations between the concentrations of 4 perfluoroalkyl sulfonic acids (PFSAs) and 11 perfluoroalkyl carboxylic acids (PFCAs) in the eggs of great tits (Parus major), collected along a distance gradient from a pollution source, and multiple reproductive parameters (including the start of egg laying, clutch size, hatching success, fledging success and total breeding success) along with egg shell thickness and body condition of the nestlings. The PFAA concentrations measured at the plant site were among the highest ever reported in wild bird eggs. PFAA concentrations decreased sharply with increasing distance (0-11 km) from the plant, but remained relatively elevated in the adjacent sites. PFAAs were grouped into principal components (PCs) to prevent collinearity. High concentrations of PFOS, PFDS, PFDoDA, PFTrDA and PFTeDA (grouped as PC1) were associated with a reduced hatching success of nests where at least one egg hatched, thinner egg shells and increased survival of the hatched chicks. High concentrations of PFDA (PC2) were associated with a reduced hatching success, especially in nests where no eggs hatched, an earlier start of egg laying and a reduction of total breeding success, mainly caused by the failure in hatching. Although the major manufacturer of PFAAs phased out the production of perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and related products in 2002, concentrations appear to have increased since previous measurements. Surprisingly, despite the very high concentrations close to the fluorochemical plant, there was no clear evidence for reproductive impairment as the observed associations between PFAA concentrations and reproductive parameters were rather limited compared to previous studies in songbirds. These findings also suggest potential differences in sensitivity between species. CAPSULE: Despite the very high PFAA concentrations at the perfluorochemical hotspot, correlations with reproductive parameters were limited.

Developmental Toxicity of Perfluorooctanesulfonate (PFOS) and Its Chlorinated Polyfluoroalkyl Ether Sulfonate Alternative F-53B in the Domestic Chicken

The chlorinated polyfluoroalkyl ether sulfonate F-53B is used as a mist suppressant in the Chinese electroplating industry. Because of the regulations on perfluorooctanesulfonate (PFOS), its use is expected to increase. Until now, F-53B toxicity data have been scarce and are, to our knowledge, lacking for birds. This study therefore investigated the effects of PFOS and F-53B, separately and as mixtures, on the development of the chicken ( Gallus gallus domesticus). Compounds were injected in ovo, before incubation, at 150 and 1500 ng/g egg. At embryonic day 20, a significantly lower heart rate was observed in all treated groups compared to the control group and hatchlings exposed to the high dose of F-53B had a significantly enlarged liver (8%). Embryonic survival was not affected and no significant effects on hatchling body mass or oxidative stress parameters were found. Our results suggest that these compounds likely have different toxicity thresholds for the investigated endpoints, and/or different modes of action. This study thereby underlines the potential developmental toxicity of PFOS and F-53B at environmentally relevant concentrations. Assessment of PFOS alternatives should therefore continue, preferably prior to their large scale use, as they should be ensured to be less harmful than PFOS itself.

Effects of perfluorooctane sulfonate on genes controlling hepatic fatty acid metabolism in livers of chicken embryos

Per- and polyfluoroalkyl substances (PFAS) are synthetic surfactants with a wide variety of applications; however, due to their stability, they are particularly resistant to degradation and, as such, are classed as persistent organic pollutants. Perfluorooctane sulfonate (PFOS) is one such PFAS that is still detectable in a range of different environmental settings, despite its use now being regulated in numerous countries. Elevated levels of PFOS have been detected in various avian species, and the impact of this on avian health is of interest when determining acceptable levels of PFOS in the environment. Due to its similarities to naturally occurring fatty acids, PFOS has potential to disrupt a range of biological pathways, particularly those associated with lipid metabolism, and this has been shown in various species. In this study, we have investigated how in ovo exposure to environmentally relevant levels of PFOS affects expression of genes involved in lipid metabolism of developing chicken embryos. We have found a broad suppression of transcription of genes involved in fatty acid oxidation and PPAR-mediated transcription with more significant effects apparent at lower doses of PFOS. These results highlight the need for more research investigating the biological impacts of low levels of PFAS to properly inform environmental policy governing their regulation.

Mitochondrial toxicity of perfluorooctane sulfonate in mouse embryonic stem cell-derived cardiomyocytes

Perfluorooctane sulfonate (PFOS) is a persistent organic contaminant that may cause cardiotoxicity in animals and humans. However, little is known about the underlying mechanism by which it affects the organelle toxicity in cardiomyocytes during the cardiogenesis. Our previous proteomic study showed that differences of protein expression mainly existed in mitochondria of cardiomyocytes differentiated from embryonic stem (ES) cells after exposure to PFOS. Here, we focused on mitochondrial toxicity of PFOS in ES cell-derived cardiomyocytes. The cardiomyogenesis from ES cells in vitro was inhibited, and the expression of L-type Ca²⁺ channel (LTCC) was decreased to interrupt [Ca²⁺]_c transient amplitude in cardiomyocytes after PFOS treatment. Transmission electron microscope revealed that swollen mitochondrion with vacuole in PFOS-treated cells. Meanwhile, mitochondrial transmembrane potential (ΔΨm) was declined and ATP production was lowered. These changes were related to the increased EGFR phosphorylation, activated Rictor signaling, then mediated HK2 binding to mitochondrial membrane. Furthermore, PFOS reduced the interaction of IP3R-Grp75-VDAC and accumulated intracellular fatty acids by activating Rictor, thereby attenuating PGC-1α and Mfn2 expressions, then destroying mitochondria-associated endoplasmic reticulum membrane (MAM), which resulted in the decrease of [Ca²⁺]_mito transient amplitude triggered by ATP. In conclusion, mitochondrial structure damages and abnormal Ca²⁺ shuttle were the important aspects in PFOS-induced cardiomyocytes toxicity from ES cells by activating Rictor signaling pathway.