Accumulation of perfluorooctane sulfonate in marine mammals

Target and suspect screening of per- and polyfluoroalkyl substances (PFASs) in consumer products using ion mobility separation high resolution mass spectrometry (IMS-HRMS)

This study aims to investigate the distribution of per- and polyfluoroalkyl substances (PFAS) and their precursors in 55 consumer products, including 27 personal care products (PCPs) from 7 categories and 28 household products (HPs) from 6 categories and analyze the correlation between them, by measuring PFASs using target analysis with LC-MS/MS and suspect screening using high-resolution mass spectrometry (HRMS) combined with ion mobility separation (IMS). In most products, perfluorocarboxylic acid (PFCA) concentrations (0.036-25.2 ng/g) exceeded perfluorosulfonic acid concentrations (n.d.-0.566 ng/g). In PCPs, the median concentrations of 12 PFASs and two fluorinated precursors (0.053-139 ng/g) were significantly higher than in HPs (0.012-76.0 ng/g) (p < 0.05). Across all PCP and HP types, short-chain PFASs (PFCAs ≤ C7; PFSAs ≤ C6) (1.68-46.9 ng/g) were also significantly higher than long-chain PFASs (0.071-6.86 ng/g) (p < 0.05). Suspect screening identified a total of 9 candidate PFASs, including the four PFCA precursors, all of which were assigned a confidence level of 3 or higher. The observed positive correlation between precursors and PFCAs (p < 0.05) suggests that precursors may be converted into PFCAs, thereby increasing PFCA concentrations, although the specific transformation pathways require further investigation. This study provides insights into the distribution of PFAS and their precursors in consumer products and demonstrates that IMS-HRMS-based suspect screening can be useful for distinguishing false positives in PFAS identification.

The quest for the perfect "total PFAS" method: how can the total oxidisable precursor (TOP) assay be made reliable?

Per- and polyfluoroalkyl substances (PFAS) make up a large and complex class of manmade chemicals. They have been widely used in numerous industrial branches and are incorporated into many consumer products. Today, there is a consensus on the fact that PFAS are present in all environmental compartments and that populations all over the world are subjected to them via internal exposure. It has been estimated that thousands of individual PFAS have been manufactured and marketed since the 1950s, to which impurities present in commercial products and intermediate environmental transformation products should be added. Since it is unrealistic to be able to individually identify, detect and quantify all the PFAS present in a sample, several analytical approaches have been developed to assess the presence of "hidden/unseen" PFAS. One of these, known as the total oxidisable precursor (TOP) assay, was first described in 2012. Basically, it converts some PFAS, hereafter referred to as precursors, into stable terminal products readily measurable by routine target methods. This review is based on more than 100 studies in which the original TOP assay was simply applied or optimised. The review found that the TOP assay was selective, sensitive, applicable to many matrices, useful within a forensic context, inexpensive, and easy to implement and has been assessed in the literature on a wide range of precursors. However, this method comprises many subtleties and has some flaws that operators should be made aware of so that they may be addressed as far as possible. Finally, this review tries to lay the foundations for better practices and quality assurance/quality control measures, in order to improve accuracy and reliability of TOP assay results.

Current Approaches in the Classification of PFAS: An Overview

Perfluoroalkyl substances (PFAS) represent a broad group of synthetic chemicals that have raised concerns related to their long-term environmental persistence and potential health risks. Although several efforts have been dedicated to establishing international restrictions on their use, the definition of what qualifies as a PFAS remains a matter of debate among scientists, regulatory agencies, and industry. This article provides a brief overview of the different approaches proposed and adopted to date for identifying and grouping of these pollutants, either based on common structural motifs or on the combination of multiple factors, including functional uses, degradation behavior, physicochemical properties, and toxicity. The diversity and complexity of PFAS substances suggests the need of a multifaceted classification system that can guide regulatory efforts, risk assessment, and environmental monitoring through standardized criteria accepted on an international scale. A pivotal role in establishing a universal definition of PFAS will be played by the International Union of Pure and Applied Chemistry (IUPAC), which is currently supporting a project on the terminology and classification of these chemicals.

Occurrence, bioaccumulation and trophodynamics of per- and polyfluoroalkyl substances (PFAS) in terrestrial and marine ecosystems of Svalbard, Arctic

Per- and polyfluoroalkyl substances (PFAS) enter the Arctic through long-range transport and local pollution. To date, little is known about their behavior in plant and benthic marine food webs in remote Arctic. In this study, we analyzed the environmental distribution and nutrient transfer of 20 PFAS in soil, sediment, plant and benthic biota samples collected between 2014 and 2016 in Svalbard, Arctic. Total concentrations of PFAS were in the ranges of 0.12-4.84 ng/g dry weight (dw) in soil, 0.15-0.93 ng/g dw in sediment, 0.11-16.6 ng/g dw in plant, and 0.049-26.2 ng/g dw in marine biota. Perfluorocarboxylic acids (PFCAs) dominated Σ20PFAS in all sample types except amphipods, in which perfluorooctane sulfonate (PFOS) made up 80 % of Σ20PFAS. The profile of PFAS components observed in the terrestrial and marine ecosystems suggests that atmospheric transport and oxidation of volatile precursors are important sources of PFCAs in the Arctic region. However, the impact of long-distance ocean transport and local emissions cannot be ignored. The biota-sediment or biota-soil bioaccumulation factors (BSAF) differed among plants and biota species, with mountain avens (BSAF of Σ20PFAS: 12.1) and amphipods (BSAF of Σ20PFAS: 44.9) having higher accumulation potential. PFOS, perfluorohexane sulfonamide (FHxSA) and Σ20PFAS have biomagnification potential in Arctic benthic biota, but short-chain PFCA exhibits trophic dilution. This is one of few studies to investigate the environmental behavior of PFAS in terrestrial and aquatic ecosystems in the remote Arctic, providing a basis for investigating the ecological risks of PFAS in polar regions.

Accumulation and trophic transfer of per- and polyfluoroalkyl substances (PFAS) in estuarine organisms determined via stable isotopes

Per- and polyfluoroalkyl substances (PFAS) are persistent organic pollutants in estuaries. In this study, 19 PFAS were quantified in surface waters, sediments, marine invertebrates (aquatic worms, Eastern oysters, and blue crab), and forage fish (Atlantic silverside, four-spine stickleback, mummichog, sheepshead minnow, and rainwater killifish) in an aqueous film forming foam (AFFF)-contaminated estuary, Georgica Pond (NY, USA). Carbon and nitrogen stable isotopes (δ13C and δ15N) were used to determine trophic position of organisms and to identify modes of PFAS exposure. The influence of salinity (8 to 26 practical salinity units, PSU) on the relative and absolute abundance of PFAS in all matrices was also investigated. Eleven long- and short-chain perfluoroalkyl acids (PFAAs) were found to have bioaccumulation potential (bioaccumulation factor, BAF; biota-sediment accumulation factor, BSAF) and were positively correlated with relative trophic position. Among these, long-chain PFAAs (perfluorohexanesulfonic acid, PFHxS; perfluorooctane sulfonic acid, PFOS; perfluorooctanoic acid, PFOA; perfluorononanoic acid, PFNA) were the greatest contributors to total body burden and bioaccumulated in all organisms, with PFOS (log BAF = 3.55 ± 0.83) and PFNA (log BAF = 3.17 ± 0.46) having the highest mean values of all compounds. PFOS was present in all biota samples and concentrations significantly increased with food web trophic position (ranging from 0.18 to 777 μg kg-1). Perfluorobutane sulfonic acid (PFBS) was also ubiquitous among all organisms, bioaccumulating in both invertebrate and vertebrate species. Total PFAS concentrations in aquatic worms were significantly higher in lower salinity water while the PFAS profile of Eastern oysters shifted from predominately perfluorocarboxylic acids (66 % of total composition) to perfluorosulfonic acids (62 %) as the ecosystem transitioned from low (9 PSU) to high (25 PSU) salinity. Collectively, this study demonstrates the utility of applying δ13C and δ15N to determine bioaccumulation patterns of both legacy PFAS and short-chain replacement compounds and underscores how shifts in salinity can alter the concentration and speciation of PFAS in estuaries.

Associations of per- and polyfluoroalkyl substances and alternatives with subclinical hypothyroidism in children: A cross-sectional study in China

There is growing experimental and epidemiological evidence linking perfluoroalkyl and polyfluoroalkyl substances (PFAS) exposure to thyroid dysfunction; however, the association between PFAS and their alternatives to subclinical hypothyroidism in children remains to be elucidated. This study investigated the association between 30 PFASs and thyroid function using serum samples from 194 children (aged 3-17 years) who participated in the Zhejiang Human Biomonitoring Program. Various thyroid function indicators, including free triiodothyronine, free thyroxine (FT4), and thyrotropin, were tested, and subclinical hypothyroidism was diagnosed. Linear regression was employed to examine the associations between individual PFASs and thyroid hormone levels, and logistic regression was applied to assess their associations with subclinical hypothyroidism. The quantile g-computation (qgcomp) method was used to examine the combined and individual effects of PFAS mixtures on thyroid function. Both PFASs and their alternatives were associated with altered thyroid hormone levels and subclinical hypothyroidism. A higher level of perfluorohexanoic acid (PFHpA) was associated with decreased FT4 with a reduction of -0.028 pmol/L (95 % confidence interval [95 % CI]: -0.047, -0.008) per unit increase as well as increased odds of subclinical hypothyroidism (odds ratio [OR] = 1.95; 95 % CI: 1.11, 3.53). Moreover, a higher PFAS mixture was associated with elevated odds of subclinical hypothyroidism (OR = 3.72; 95 % CI: 1.08, 12.85), in which PFHpA, in conjunction with 6:2 chlorinated perfluoroalkyl ether sulfonic acid, accounted for the greatest proportion of the variance. These findings augment our understanding of the adverse effects of PFASs and their alternatives on thyroid homeostasis, underscoring the need for further epidemiological research.

Spatial distribution, trophic magnification, and risk assessment of per- and polyfluoroalkyl substances in Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis): Risks of emerging alternatives

The Yangtze finless porpoise (YFP, Neophocaena asiaeorientalis asiaeorientalis) is the only freshwater cetacean found in China. However, per- and polyfluoroalkyl substances (PFASs) risks in YFPs remain unclear. In this study, legacy PFASs, their precursors and alternatives, were determined in YFP muscles (n = 32), liver (n = 29), kidney (n = 24), skin (n = 5), and blubbers (n = 25) collected from Poyang Lake (PL) and Yangtze River (YR) between 2017 and 2023. Perfluorooctane sulfonic acid (PFOS) was the predominant PFAS in all YFP tissues, with a median hepatic concentration of 1700 ng/g wet weight, which is higher than that in other finless porpoises worldwide. PFOS, chlorinated polyfluorinated ether sulfonates (Cl-PFESAs), and perfluoroalkane sulfonamides concentrations in YFP livers from PL were significantly higher than those from YR (p < 0.05); however, the opposite was observed for hexafluoropropylene oxide acids. Biomagnification and trophic magnification factors (BMF and TMF, respectively) of most PFASs in the YFP food web were > 1. Perfluoroheptane sulfonic acid had the highest BMF value (99), followed by 6:2 Cl-PFESA (94) and PFOS (81). The TMFmuscle and TMFliver values of the total PFASs were 3.4 and 6.6, respectively, and were significantly positively correlated with the fluorinated carbon chain length (p < 0.01). In addition, up to 62 % of the hazard quotients for 6:2 Cl-PFESA were > 1, which was higher than that of PFOS (48 %), suggesting a high hepatotoxicity of 6:2 Cl-PFESA to YFPs. Bioaccumulation and biotoxicity of legacy and emerging alternatives in aquatic organisms continue to be a concern, especially for underscoring the vulnerability of the long-lived and endangered species.

The pollutant perfluorohexane sulfonate (PFHxS) reduces serum thyroxine but does not alter thyroid action in the postnatal rat brain

Known as "forever chemicals", per- and polyfluoroalkyl substances (PFAS) are synthetic compounds used in consumer goods but pose significant public health concerns, including disruption of the thyroid system. As thyroid hormones (THs) are required for normal brain development, PFAS may also be developmental neurotoxicants. However, this is not well understood. Here we examine the endocrine and neurodevelopmental consequences of perfluorohexane sulfonate (PFHxS) exposure in pregnant, lactating, and developing rats, and compare its effects to an anti-thyroid pharmaceutical (propylthiouracil, PTU) that induces thyroid-mediated developmental neurotoxicity. We show that PFHxS dramatically reduces maternal serum thyroxine (T4), nearly equivalently to PTU (-55 and -51%, respectively). However, only PTU increases thyroid stimulating hormone. The lactational transfer of PFHxS is significant and reduces pup serum T4 across the postnatal period. Surprisingly, brain THs are only minimally decreased by PFHxS, whereas PTU drastically diminishes them. Evaluation of brain TH action by phenotyping, RNA-Sequencing, and quantification of radial glia cell morphology supports that PTU interrupts TH signaling while PFHxS has limited to no effect. These data show that PFHxS induces abnormal serum TH profiles; however, there were no indications of hypothyroidism in the postnatal brain. We suggest the stark differences between the neurodevelopmental effects of PFHxS and a typical antithyroid agent may be due to its interaction with TH distributing proteins like transthyretin.

Accumulation of Per- and Polyfluoroalkyl Substances (PFAS) in Coastal Sharks from Contrasting Marine Environments: The New York Bight and The Bahamas

Per- and polyfluoroalkyl substances (PFAS) enter the marine food web, accumulate in organisms, and potentially have adverse effects on predators and consumers of seafood. However, evaluations of PFAS in meso-to-apex predators, like sharks, are scarce. This study investigated PFAS occurrence in five shark species from two marine ecosystems with contrasting relative human population densities, the New York Bight (NYB) and the coastal waters of The Bahamas archipelago. The total detected PFAS (∑PFAS) concentrations in muscle tissue ranged from 1.10 to 58.5 ng g-1 wet weight, and perfluorocarboxylic acids (PFCAs) were dominant. Fewer PFAS were detected in Caribbean reef sharks (Carcharhinus perezi) from The Bahamas, and concentrations of those detected were, on average, ∼79% lower than in the NYB sharks. In the NYB, ∑PFAS concentrations followed: common thresher (Alopias vulpinus) > shortfin mako (Isurus oxyrinchus) > sandbar (Carcharhinus plumbeus) > smooth dogfish (Mustelus canis). PFAS precursors/intermediates, such as 2H,2H,3H,3H-perfluorodecanoic acid and perfluorooctanesulfonamide, were only detected in the NYB sharks, suggesting higher ambient concentrations and diversity of PFAS sources in this region. Ultralong-chain PFAS (C ≥ 10) were positively correlated with nitrogen isotope values (δ15N) and total mercury in some species. Our results provide some of the first baseline information on PFAS concentrations in shark species from the northwest Atlantic Ocean, and correlations between PFAS, stable isotopes, and mercury further contextualize the drivers of PFAS occurrence.

In vitro toxicity of Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) on Human Renal and Hepatoma Cells

We evaluate the cytotoxicity, intracellular redox conditions, apoptosis, and methylation of DNMTs/TETs upon exposure to LiTFSI, a novel Per and Polyfluoroalkyl Substances (PFAS) commonly found in lithium-ion batteries, on human renal carcinoma cells (A498) and hepatoma cells (HepG2). The MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay showed both Perfluorooctane sulfonate (PFOS) and Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) had a dose-dependent effect on A498 and HepG2, with LiTFSI being less toxic. Intracellular redox conditions were assessed with a microplate reader and confocal, which showed a significant decrease in Reactive Oxygen Species (ROS) levels and an increase in Superoxide dismutase (SOD) content in both cells. Exposure to LiTFSI enhanced cell apoptosis, with HepG2 being more susceptible than A498. Quantitative analysis of mRNA expression levels of 19 genes associated with kidney injury, methylation, lipid metabolism and transportation was performed. LiTFSI exposure impacted kidney function by downregulating smooth muscle alpha-actin (Acta2) and upregulating transforming growth factor beta 1 (Tgfb1), B-cell lymphoma 2-like 1) Bcl2l1, hepatitis A virus cellular receptor 1 (Harvcr1), nuclear factor erythroid 2-like 2 (Nfe2l2), and hairy and enhancer of split 1 (Hes1) expression. LiTFSI exposure also affected the abundance of transcripts associated with DNA methylation by the expression of ten-eleven translocation (TET) and DNA methyltransferase (DNMT) genes. Furthermore, LiTFSI exposure induced an increase in lipid anabolism and alterations in lipid catabolism in HepG2. Our results provide new insight on the potential role of a new contaminant, LiTFSI in the regulation of oxidative stress, apoptosis and methylation in human renal carcinoma and hepatoma cells.

Accumulation features and temporal trends (2002-2015) for legacy and emerging per- and polyfluoroalkyl substances (PFASs) in finless porpoises bycaught off Korean coasts

Legacy and emerging per- and polyfluoroalkyl substances (PFASs) were measured in livers of finless porpoises (Neophocaena asiaeorientalis; n = 167) collected in Korean waters from 2002 to 2015 to investigate their occurrence, bioaccumulation feature, temporal trends, and ecotoxicological implications. Perfulorooctane sulfonate (PFOS), perfluoroundecanoate (PFUnDA), and perfluorotridecanoate (PFTrDA) were the predominant PFASs found in the porpoises. The concentration of 6:2 chlorinated polyfluoroalkyl ether sulfonate (F-53B), an alternative to PFOS, was comparable to that of PFTrDA. Perfluorooctane sulfonamide (FOSA), a precursor of PFOS, was also detected in all the porpoises examined. All PFASs, including F-53B, accumulated to higher concentrations in immature porpoises compared with mature specimens, implying substantial maternal transfer and limited metabolizing capacity for PFASs. A significant correlation was observed between PFOS and F-53B concentrations, indicating similar bioaccumulation processes. Based on prenatal exposure and toxicity, F-53B is an emerging contaminant in marine ecosystems. Significantly increasing trends were observed in the concentrations of sulfonates, carboxylates, and F-53B between 2002/2003 and 2010, whereas the FOSA concentration significantly decreased. During 2010-2015, decreasing trends were observed in the concentrations of FOSA and sulfonates, whereas concentrations of carboxylate and F-53B increased without statistical significance, likely due to a gap for the implementation of regulatory actions between sulfonates and carboxylates. Although PFOS and PFOA were found to pose little health risk to porpoises, the combined toxicological effects of other contaminants should be considered to protect populations and to mitigate PFAS contamination in marine ecosystems.

Evaluation of fatty acids and carnitine as biomarkers of PFOS exposure in biota (fish and dolphin) from Galveston Bay and the northwestern Gulf of Mexico

Perfluorooctane sulfonate (PFOS) is a ubiquitous pollutant that elicits a wide range of toxic effects in exposed biota. Coastal zones in highly urbanized or industrial areas are particularly vulnerable to PFOS pollution. At present, information is lacking on biomarkers to assess PFOS effects on aquatic wildlife. This study investigated the efficacy of l-carnitine (or carnitine) and fatty acids as biomarkers of PFOS exposure in aquatic biota. The levels of PFOS, total and free carnitine, and 24 fatty acids (measured as fatty acid methyl esters or FAMEs) were measured in the liver, and muscle or blubber, of fish and dolphins sampled from Galveston Bay and the northern Gulf of Mexico (nGoM). Overall, bottlenose dolphins (Tursiops truncatus) had the highest hepatic PFOS levels. Galveston Bay fish, gafftopsail catfish (Bagre marinus), red drum (Sciaenops ocellatus), and spotted seatrout (Cynoscion nebulosus), had hepatic PFOS levels ∼8-13× higher than nGoM pelagic fish species, red snapper (Lutjanus campechanus) and yellowfin tuna (Thunnus albacares). The multivariate analysis of PFOS liver body-burdens and biomarkers found carnitine to be a more modal biomarker of PFOS exposure than FAMEs. Significant positive correlation of hepatic PFOS levels with total carnitine was evident for biota from Galveston Bay (fish only), and a significant correlation between PFOS and total and free carnitine was evident for biota from the nGoM (fish and dolphins). Given the essential role of carnitine in mediating fatty acid β-oxidation, our results suggest carnitine to be a likely candidate biomarker of environmental PFOS exposure and indicative of potential dyslipidemia effects.

Biomagnification and temporal trends (1990-2021) of perfluoroalkyl substances in striped dolphins (Stenella coeruleoalba) from the NW Mediterranean sea

Poly- and Perfluoroalkyl Substances (PFAS) are a well-known class of pollutants which can bioaccumulate and biomagnify with a vast majority being highly persistent. This study aims to determine the biomagnification rates of PFAS in sexually mature striped dolphins and to assess temporal trends on PFAS concentrations over the past three decades (1990-2021) in the North-Western Mediterranean Sea. Thirteen and 17 of the 19 targeted PFAS were detected in the samples of the dolphins' digestive content and liver, respectively, at concentrations ranging between 43 and 1609 ng/g wet weight, and 254 and 7010 ng/g wet weight, respectively. The most abundant compounds in both types of samples were linear perfluorooctanesulfonic acid (n-PFOS) and perfluorooctanesulfonamide (FOSA), which were present in all samples, followed by perfluoroundecanoic acid (PFUnDA), perfluorotridecanoic acid (PFTrDA) and perfluorononanoic acid (PFNA). Long-chain PFAS (i.e., PFCAs C ≥ 7 and PFSAs C ≥ 6) biomagnified to a greater extent than short-chain PFAS, suggesting a potential effect on the health of striped dolphins. Environmental Quality Standards concentrations set in 2014 by the European Union were exceeded in half of the samples of digestive content, suggesting that polluted prey may pose potential health risks for striped dolphins. Concentrations of most long-chain PFAS increased from 1990 to 2004-2009, then stabilized during 2014-2021, possibly following country regulations and industrial initiatives. The current study highlights the persistent presence of banned PFAS and may contribute to future ecological risk assessments and the design of management strategies to mitigate PFAS pollution in marine ecosystems.

Identification of key features relating to the coexistence mechanisms of trace elements and per- and polyfluoroalkyl substances (PFASs) in marine mammals

Organic and inorganic substances coexist in the livers of marine mammals and may correlate with one another; however, their coexistence mechanisms and relevant key features remain largely unknown. In this study, temporal variations (2011-2021) in the concentrations of nine trace elements and 19 per- and polyfluoroalkyl substances (PFASs) in the livers of Indo-Pacific humpback dolphins (Sousa chinensis) and finless porpoises (Neophocaena phocaenoides) were investigated. Interannual Cd in dolphins increased significantly whereas Pb concentrations decreased over the past decade (p < 0.05). Interannual levels of seven and four PFASs in dolphins and porpoises decreased significantly with time (p < 0.05). By further extending the timescale to 1993-2021, the sensitivity of trace elements to annual change further increased, whereas the sensitivity of PFASs remained relatively stable. Cu levels, similar to the majority of PFASs, were negatively correlated with the body length of the studied cetaceans, which led to positive correlations of Cu with six long-chain perfluoroalkyl carboxylic acids, perfluorodecane sulfonic acid, and perfluoroethylcyclohexane sulfonic acid. The concentrations of trace elements in the cetacean liver were closely correlated with cetacean sex, species, and body length, whereas PFAS concentration was responsive to time-related features such as stranded season and year. By further employing a machine learning method, we demonstrated that body length and a time-related factor (year) played a crucial role in predicting the concentrations of certain trace elements and PFASs, respectively, particularly Cu and perfluoroheptanoic acid.

Experimental Determination of Air/Water Partition Coefficients for 21 Per- and Polyfluoroalkyl Substances Reveals Variable Performance of Property Prediction Models

Per- and polyfluoroalkyl substances (PFAS) are a group of chemicals of high environmental concern. However, reliable data for the air/water partition coefficients (Kaw), which are required for fate, exposure, and risk analysis, are available for only a few PFAS. In this study, Kaw values at 25 °C were determined for 21 neutral PFAS by using the hexadecane/air/water thermodynamic cycle. Hexadecane/water partition coefficients (KHxd/w) were measured with batch partition, shared-headspace, and/or modified variable phase ratio headspace methods and were divided by hexadecane/air partition coefficients (KHxd/air) to obtain Kaw values over 7 orders of magnitude (10-4.9 to 102.3). Comparison to predicted Kaw values by four models showed that the quantum chemically based COSMOtherm model stood out for accuracy with a root-mean-squared error (RMSE) of 0.42 log units, as compared to HenryWin, OPERA, and the linear solvation energy relationship with predicted descriptors (RMSE, 1.28-2.23). The results indicate the advantage of a theoretical model over empirical models for a data-poor class like PFAS and the importance of experimentally filling data gaps in the chemical domain of environmental interest. Kaw values for 222 neutral (or neutral species of) PFAS were predicted using COSMOtherm as current best estimates for practical and regulatory use.

Warming Affects Bioconcentration and Bioaccumulation of Per- and Polyfluoroalkyl Substances by Pelagic and Benthic Organisms in a Water-Sediment System

Warming and exposure to emerging global pollutants, such as per- and polyfluoroalkyl substances (PFAS), are significant stressors in the aquatic ecosystem. However, little is known about the warming effect on the bioaccumulation of PFAS in aquatic organisms. In this study, the pelagic organisms Daphnia magna and zebrafish, and the benthic organism Chironomus plumosus were exposed to 13 PFAS in a sediment-water system with a known amount of each PFAS at different temperatures (16, 20, and 24 °C). The results showed that the steady-state body burden (C_b-ss) of PFAS in pelagic organisms increased with increasing temperatures, mainly attributed to increased water concentrations. The uptake rate constant (k_u) and elimination rate constant (k_e) in pelagic organisms increased with increasing temperature. In contrast, warming did not significantly change or even mitigate C_b-ss of PFAS in the benthic organism Chironomus plumosus, except for PFPeA and PFHpA, which was consistent with declined sediment concentrations. The mitigation could be explained by the decreased bioaccumulation factor due to a more significant percent increase in k_e than k_u, especially for long-chain PFAS. This study suggests that the warming effect on the PFAS concentration varies among different media, which should be considered for their ecological risk assessment under climate change.

Investigation of the potential effects of firefighting water additives on soil invertebrates and terrestrial plants

The intensity and frequency of forest fires is increasing across the globe due to climate change. Additives are often added to make water more effective at extinguishing fire and preventing re-ignition. This study investigated the toxicity of nine different firefighting water additives to four species of soil invertebrates (Folsomia candida, Porcellio laevis, Porcellio scaber, and Trichorhina tomentosa) and two plant species (Agropyron cristatum and Raphanus sativus). Considerable variation in toxicity was observed among the firefighting products. The toxicity of individual products also varied considerably amongst the tested species. A hazard assessment was conducted by comparing the concentration of firefighting water additive that caused a 50% effect (LC50 or EC50) or a concentration that caused no effect (NOEC) to the concentration recommended by the manufacturer. At a rate of application representative of a forest firefighting scenario, most firefighting water additives tested in this study posed a hazard to F. candida and the three isopod species. The majority of products did not pose a risk to the two plant species included in this study. Consideration of the toxicity of firefighting water additives to terrestrial biota should be considered along with the efficacy of the product to fight fires when deciding which products to use.

Emerging Contaminants and New POPs (PFAS and HBCDD) in Endangered Southern Resident and Bigg's (Transient) Killer Whales (Orcinus orca): In Utero Maternal Transfer and Pollution Management Implications

Killer whales (Orcinus orca) have been deemed one of the most contaminated cetacean species in the world. However, concentrations and potential health implications of selected 'contaminants of emerging concern' (CECs) and new persistent organic pollutants (POPs) in endangered Southern Resident and threatened Bigg's (Transient) killer whales in the Northeastern Pacific (NEP) have not yet been documented. Here, we quantify CECs [alkylphenols (APs), triclosan, methyl triclosan, and per- and polyfluoroalkyl substances (PFAS)] and new POPs [hexabromocyclododecane (HBCCD), PFOS, PFOA, and PFHxS] in skeletal muscle and liver samples of these sentinel species and investigate in utero transfer of these contaminants. Samples were collected from necropsied individuals from 2006 to 2018 and analyzed by LC-MS/MS or HRBC/HRMS. AP and PFAS contaminants were the most prevalent compounds; 4-nonylphenol (4NP) was the predominant AP (median 40.84 ng/g ww), and interestingly, 7:3-fluorotelomer carboxylic acid (7:3 FTCA) was the primary PFAS (median 66.35 ng/g ww). Maternal transfer ratios indicated 4NP as the most transferred contaminant from the dam to the fetus, with maternal transfer rates as high as 95.1%. Although too few killer whales have been screened for CECs and new POPs to infer the magnitude of contamination impact, these results raise concerns regarding pathological implications and potential impacts on fetal development and production of a viable neonate. This study outlines CEC and new POP concentrations in killer whales of the NEP and provides scientifically derived evidence to support and inform regulation to mitigate pollutant sources and contamination of Southern Resident killer whale critical habitat and other marine ecosystems.

Potential risk to aquatic biota from aerial application of firefighting water additives

The frequency and severity of forest fires is increasing due to climate change. Consequently, there will be an increased use of forest firefighting additives, which increase the ability of water to extinguish fires and prevent reignition. Increased use will potentially result in increased exposure to aquatic ecosystems within forests. This study examined the toxicity of nine firefighting water additives that are currently on the market to three species of freshwater invertebrates that occupy different niches within freshwater ecosystems. The toxicity of the water additives varied up to three orders of magnitude. Pelagic and epibenthic invertebrates are affected at lower rates of application than endobenthic invertebrates. A field relevant application rate of three of the nine water additives tested represent a hazard to freshwater ecosystems under varies exposure scenarios represented by the depth of a theoretical water body (15-200 cm). This study highlights the importance of application buffers around water bodies and the selection of water additives that pose the lowest hazard to freshwater ecosystem, assuming that the efficacy of the additives in extinguishing fires is similar.

Targeted PFAS analyses and extractable organofluorine - Enhancing our understanding of the presence of unknown PFAS in Norwegian wildlife

With the current possible presence of thousands of PFAS compounds in industrial emissions, there is an increasing need to assess the impacts of PFAS regulation of conventional PFAS on one hand and the exposure to emerging and yet unknown PFAS on the other. Today's analytical methodologies using targeted approaches are not sufficient to determine the complete suite of PFAS present. To evaluate the presence of unknown PFAS, we investigated in this study the occurrence of an extended range of target PFAS in various species from the marine and terrestrial Norwegian environment, in relation to the extractable organofluorine (EOF), which yields the total amount of organofluorine. The results showed a varying presence of extractable fluorinated organics, with glaucous gull eggs, otter liver and polar bear plasma showing the highest EOF and a high abundance of PFAS as well. The targeted PFAS measurements explained 1% of the organofluorine for moose liver as the lowest and 94% for otter liver as the highest. PFCAs like trifluoroacetic acid (TFA, reported semi-quantitatively), played a major role in explaining the organic fluorine present. Emerging PFAS as the perfluoroethylcyclohexane sulfonate (PFECHS), was found in polar bear plasma in quantifiable amounts for the first time, confirming earlier detection in arctic species far removed from emission sources. To enable a complete organic fluorine mass balance in wildlife, new approaches are needed, to uncover the presence of new emerging PFAS as cyclic- or ether PFAS together with chlorinated PFAS as well as fluorinated organic pesticides and pharmaceuticals.

Spatiotemporal and life history related trends of per- and polyfluoroalkyl substances in Indo-Pacific finless porpoises from south China sea (2007-2020)

Per- and polyfluoroalkyl substances (PFASs) levels in Indo-Pacific finless porpoises (Neophocaena phocaenoides) in the Pearl River Estuary (PRE), near the most economically developed region in China, have not been characterized. We measured the hepatic concentrations of twelve PFASs, including nine perfluoroalkyl carboxylic acids (PFCAs) and three perfluoroalkane sulfonic acids (PFSAs) in the finless porpoises (n = 21) collected from the PRE between 2007 and 2020. The average level of PFSAs was more than 2-times higher than that of PFCAs. The order of six dominant PFASs was perfluorooctane sulfonate (PFOS) > perfluoroundecanoic acid (PFUdA) > perfluorodecanoic acid (PFDA) > perfluorotridecanoic acid (PFTrDA) > perfluorononanoic acid (PFNA) > perfluorododecanoic acid (PFDoDA). The levels of Hepatic PFOS of 29% samples exceeded the no observable adverse effect level (NOAEL) values. The concentration of PFASs in males was significant higher than in females. PFASs levels were significantly negatively correlated with body length in males and positively correlated in females. PFASs levels in the PRE finless porpoises were lower than in humpback dolphins possibly due to different foraging habitat toward the coast and the consumption of less fish. PFCAs levels in finless porpoises from the western PRE were higher compared to Hong Kong, possibly due to the high-intensity sources of terrestrial anthropogenic pollutants. Significant increasing spatiotemporal trends of PFSAs, PFCAs and PFASs were found in finless porpoises from 2007 to 2020, suggesting a continuously increased risk of PFASs exposure for PRE cetaceans in the last decade.

Molecular and genetic analyses revealed the phytotoxicity of perfluorobutane sulfonate

Perfluorobutane sulfonate (PFBS) has oily and hydrophobic characteristics similar to those of perfluorooctane sulfonic acid (PFOS), which is an environmental organic pollutant and has gradually become the main substitute for PFOS in industry. Several studies have revealed the potential toxicity of PFBS in animals. PFBS can be taken up and accumulate in plants; however, whether and how PFBS affects plant growth remain largely unclear. A low concentration of PFBS did not affect plant growth, indicating that it had higher environmental safety than other perfluorinated compounds; however, a high concentration of PFBS (>1 mM) markedly inhibited primary root growth in Arabidopsis thaliana. Subsequently, we investigated the molecular mechanisms underlying plant growth mediated by high concentrations of PFBS. First, a genome-wide transcriptomic analysis revealed that PFBS altered the expression of genes associated with phytohormone signaling pathways. Combining physio-biochemical and genetic analyses, we next demonstrated that PFBS reduced the contents of indole-3-acetic acid (IAA) and abscisic acid (ABA), and disrupted the two signaling pathways in plants, finally inhibiting root growth. Moreover, a high concentration of PFBS also inhibited photosynthesis by comprehensively repressing the expression of genes related to the Calvin cycle and the photosynthetic apparatus. Such an understanding is helpful for elucidating the phytotoxicity of PFBS and provides a new strategy for toxicology research on organic pollutants in plants.

The development and function of the brain barriers - an overlooked consideration for chemical toxicity

It is well known that the adult brain is protected from some infections and toxic molecules by the blood-brain and the blood-cerebrospinal fluid barriers. Contrary to the immense data collected in other fields, it is deeply entrenched in environmental toxicology that xenobiotics easily permeate the developing brain because these barriers are either absent or non-functional in the fetus and newborn. Here we review the cellular and physiological makeup of the brain barrier systems in multiple species, and discuss decades of experiments that show they possess functionality during embryogenesis. We next present case studies of two chemical classes, perfluoroalkyl substances (PFAS) and bisphenols, and discuss their potential to bypass the brain barriers. While there is evidence to suggest these pollutants may enter the developing and/or adult brain parenchyma, many studies suffer from confounding technical variables which complicates data interpretation. In the future, a more formal consideration of brain barrier biology could not only improve understanding of chemical toxicokinetics but could assist in prioritizing environmental xenobiotics for their neurotoxicity risk.

Treatment of electropolishing industrial wastewater and its impact on the immobilisation of Daphnia magna

The amount of industrial pollution entering the environment and its impact on living organisms is an ongoing concern. At the same time, due to an increasing awareness, new methods of wastewater treatment are being explored that are not only effective but also environmentally acceptable. Meeting environmental standards for permitted concentrations is a necessity, but investigating the effects of wastewater on living organisms is also an important issue. In this paper, the influence of metal ions (Fe(III), Cr(III), Ni(II), Cu(II)) in industrial wastewater from electropolishing of stainless steel on Daphnia magna has been investigated. Daphnids have been exposed to wastewater both before and after treatment (Ca(OH)₂ precipitation, sorption with peat). Immobilisation in a 48-h acute toxicity test and EC₅₀ has been determined. In the case of studied industrial wastewater, the organic content (expressed as total organic carbon) of the effluent has a positive impact in terms of the survival of D. magna and increases the range of heavy metal concentrations tolerated by them. The application of a two-stage process with Ca(OH)₂ neutralisation followed by sorption with peat allows for the removal of almost 100% of metal ions from the wastewater. The reduction obtained ensured a limited impact on D. magna and a decrease in immobilisation to less than 10%. Proper execution of the wastewater treatment process ensures a reduction of its negative impact on living organisms.

Perfluoroalkyl substances (PFAS) in freshwater fish from urban lakes in Hanoi, Vietnam: concentrations, tissue distribution, and implication for risk assessment

Concentrations and profiles of 17 perfluoroalkyl substances (PFAS) including 13 perfluorocarboxylic acids (PFA) and 4 perfluoroalkyl sulfonates (PFS) were determined in whole blood, muscle, and liver samples of four freshwater fish species in West Lake and Yen So Lake (Hanoi, Vietnam). Concentrations of total 17 PFAS in fish blood samples ranged from 5.2 to 29 (median 16) ng/mL. Total 17 PFAS levels in liver samples (4.5; 2.7-6.6 ng/g wet weight) were significantly higher than in muscle samples (1.0; 0.51-2.6 ng/g wet weight). More than 90% PFAS burdens in our fish samples were attributed to muscle and blood rather than liver, but contributions of individual compounds varied greatly. The most predominant substances were perfluorooctanesulfonate (PFOS) and PFA with chain lengths from C10 to C14 (i.e., PFDA, PFUnDA, PFDoDA, PFTrDA, and PFTeDA). There is no significant difference in PFAS concentrations between the studied species (i.e., bighead carp, common carp, rohu, and tilapia), but common carp showed specific PFAS profiles as compared to other species (e.g., higher proportions of PFOS and long-chain PFA such as PFTrDA, PFTeDA, and PFHxDA). Daily intake doses of PFOS and perfluorooctanoic acid (PFOA) through fish consumption were markedly lower than the US EPA reference dose of 20 ng/kg/day. Weekly intakes of the sum of PFHxS, PFOS, PFOA, and PFNA in our study were still lower than the EFSA tolerable weekly intake of 4.4 ng/kg/week.

Elevated levels of per- and polyfluoroalkyl substances (PFAS) in freshwater benthic macroinvertebrates from the Hudson River Watershed

Per- and polyfluoroalkyl substances (PFAS) are contaminants of global concern due to their persistence and associated negative health effects. Considerable attention has been given to monitoring PFAS in the aquatic environment, however, few investigations have done so using freshwater benthic macroinvertebrates (BMIs). As these bottom-dwelling animals are known to bioconcentrate exogenous pollutants to a high degree, studying their PFAS levels may provide a more integrated view of PFAS contamination in the aquatic environment. In this study, BMIs, sediment, and surface water were collected from two streams in the Hudson River Watershed (one historically-impacted by PFAS) and analyzed for 44 PFAS using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Orbitrap high-resolution mass spectrometry (HRMS) was used to confirm the identities of quantitated analytes. Across all matrices, 17 analytes were detected with PFOA dominating in surface water and PFOS in sediment/BMIs. PFOS bioaccumulation factors (BAFs) were approximately one order of magnitude higher than those of PFOA and ranged from 857 to 5151 L kg^-1 across different BMI taxa. While PFAS concentrations in surface water and sediment were not excessively high, elevated levels were still measured in most BMI taxa. This observation suggests that the extent of PFAS contamination in a local system may be severely underestimated if only surface water and sediment are used for monitoring. Moreover, these findings have relevance for human exposure assessment considering BMIs are the primary food source of many fish.

Levels and profiles of perfluorinated alkyl acids in liver tissues of birds with different habitat types and trophic levels from an urbanized coastal region of South Korea

Contamination status and characteristics of perfluorinated alkyl acids (PFAAs) including perfluorinated carboxylic acids (PFCAs) and perfluorinated sulfonic acids (PFSAs) was examined using liver tissue of birds - black-tailed gulls (Larus crassirostris), domestic pigeons (Columba livia var. domestica), pacific loons (Gavia pacifica), herons (Ardea cinerea), and egrets (Egretta garzetta and Ardea alba) - with different trophic levels, habitat types and migratory behaviors from an industrialized coastal region of South Korea. A wide range of PFAAs (1.09 ng/g to 1060 ng/g; median = 52.6 ng/g) were detected in bird livers from the Korean coasts with high detection frequency. Accumulation features of PFAAs in birds indicated that primarily trophic position and secondly habitat type influence the levels and composition of PFAAs, e.g., relatively high PFAA levels and high composition of odd-numbered long carbon chain PFCAs (perfluoroundecanoic acid (PFUnDA) and perfluorotridecanoic acid (PFTriDA)) and PFOS in higher trophic and marine birds. The prevalence of long carbon chain (≥14) PFCAs likely implies a wide use of fluorotelomer-based substances in Korea. Interspecies comparison in the accumulation profile of persistent organic pollutants (including polychlorinated biphenyls (PCBs), organochlorine pesticides, polybrominated diphenylethers (PBDEs), and PFAAs) reveals relatively high load of PFAAs in inland (pigeons) and estuarine (egrets/herons) species compared to marine bird species, indicating wide use of PFAAs in the terrestrial environment.

Assessment of per- and polyfluoroalkyl substances in Biscayne Bay surface waters and tap waters from South Florida

Per- and polyfluoroalkyl substances (PFAS) are persistent anthropogenic pollutants present in many environmental media worldwide due to their extensive uses in many industrial and commercial products combined with their high thermal and chemical stabilities. Its ubiquitous presence in surface and drinking water supply and significant adverse health effects observed in wildlife and humans, associated with its bioaccumulation potential, pose big concerns. In this study, we have developed and validated a semi-automated solid phase extraction (SPE) followed by liquid chromatography-mass spectrometry (LC-MS/MS) for the determination of legacy and emerging short-chain PFAS substitutes in surface and tap water at low parts-per-trillion (ppt) levels in South Florida environments. Surface waters from Biscayne Bay and adjacent canals (n = 15) and tap waters from different counties (Miami-Dade, Broward, and Palm Beach County) (n = 21) were collected between October 2020 (wet season) and February 2021 (dry season). Total PFAS concentrations up to 242 ng L^-1 (average of 168 ng L^-1) were found in tap water from Grapeland Heights, which is the closest location to the Miami international airport that was sampled. The highest average total PFAS level of 106 ng L^-1 was observed in surface water from the Biscayne Canal C-8 for the wet and dry season. In general, average total PFAS was higher in tap water (86.3 ng L^-1) than in surface waters (46.3 ng L^-1), whereas the most predominant and frequently detected PFAS were PFBA, PFBS, PFPeA, PFHxA, PFHxS, PFOA and PFOS. PFAS levels found could represent a high human health risk, and ecological risk based on PFOS levels above recommended thresholds are also noted. Such knowledge on PFAS occurrence, distribution and sources in South Florida will provide essential information for local and regional regulatory agencies related to water quality, further facilitating the development of guidelines and procedures for PFAS pollution control and reduction in Florida.

Per- and polyfluoroalkyl substances (PFAS), trace elements and life history parameters of mass-stranded common dolphins (Delphinus delphis) in New Zealand

Profiles of 33 PFAS analytes and 12 essential and non-essential trace elements were measured in livers of stranded common dolphins (Delphinus delphis) from New Zealand. PFAS concentrations reported were largely comparable to those measured in other marine mammal species globally and composed mostly of long-chain compounds including perfluorooctanesulfonic acid (PFOS), perfluorododecanoic acid (PFDoDA), perfluorotridecanoic acid (PFTrDA) and perfluorooctanesulfonamide (FOSA). PFAS profiles did not vary significantly by location, body condition, or life history. Notably, significant positive correlations were observed within respective PFAS and trace elements. However, only negative correlations were evident between these two contaminant types, suggesting different exposure and metabolic pathways. Age-associated concentrations were found for PFTrDA and four trace elements, i.e. silver, mercury, cadmium, selenium, indicating differences in the bioaccumulation biomagnification mechanisms. Overall, our results contribute to global understanding of accumulation of PFAS by offering first insights of PFAS exposure in cetaceans living within South Pacific Australasian waters.

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.

Assessment of regional and temporal trends in per- and polyfluoroalkyl substances using the Oriental Magpie (Pica serica) in Korea

Per- and polyfluoroalkyl substances (PFASs) are used in industrial and commercial products due to their amphiphilic properties. Birds have been utilized as biomonitoring species due to their environmental pollutant vulnerability and wide distribution. The Oriental Magpie (Pica serica) is a representative residential species inhabiting terrestrial environments. In this study, we measured PFAS concentrations in Magpie liver tissue (n = 253) collected from 12 Korean regions in 2004 and 2017. The predominant compounds were perfluorooctanesulfonic acid (PFOS; mean: 23.8 ng/g wet weight), perfluorotridecanoic acid (PFTrDA; 2.79 ng/g), and perfluoroundecanoic acid (PFUnDA: 2.11 ng/g). We observed significant correlations between Magpie PFAS measurements, indicating similar sources and bioaccumulation processes. Adult females showed significantly lower PFOS concentrations than adult males and young males and females, indicating that avian sex is a crucial physiological factor of PFAS accumulation. PFOS, perfluorodecanoic acid (PFDA), and perfluorotetradecanoic acid (PFTeDA) concentrations in urban regions were significantly higher than rural regions. PFOS concentrations in Magpie livers increased significantly between sampling years, whereas C11-C13 carboxylic acids (PFCAs) decreased. This suggests that urbanization and population are major factors in Magpie PFAS accumulation. Almost all hepatic PFOS concentrations were below the threshold values proposed by previous studies, implying limited risks. Our findings suggest that the Oriental Magpies are PFAS sentinel in residential environments. This is the first comprehensive report on biomonitoring of PFASs using the Oriental Magpie.

Per and polyfluoroalkyl substances (PFAS) at high concentrations in neonatal Australian pinnipeds

Per and polyfluorinated substances (PFAS) exposure was investigated in Australian pinnipeds. Concentrations of 16 PFAS were measured in the livers of Australian sea lion (Neophoca cinerea), Australian fur seal (Arctocephalus pusillus doriferus) and a long-nosed Fur Seal (Arctocephalus forsteri) pup sampled between 2017 and 2020 from colonies in South Australia and Victoria. Findings reported in this study are the first documented PFAS concentrations in Australian pinnipeds. Median and observed range of values in ng/g wet weight were highest for perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA) in the liver of N. cinerea (PFOS = 7.14, 1.00-16.9; PFOA = 2.73, 0.32-11.2; PFNA = 2.96, 0.61-8.22; n = 28), A. forsteri (PFOS = 15.98, PFOA = 2.02, PFNA = 7.86; n = 1) and A. p. doriferus (PFOS = 27.4, 10.5-2119; PFOA = 0.98, 0.32-52.2; PFNA = 2.50, 0.91-44.2; n = 20). PFAS concentrations in A. p. doriferus pups were significantly greater (p < 0.05) than in N. cinerea pups for all PFAS except PFOA and were of similar magnitude to those reported in northern hemisphere marine animals. These results demonstrate exposure differences in both magnitude and PFAS profiles for N. cinerea in South Australia and A. p. doriferus in Victoria. This study reports detectable PFAS concentrations in Australian pinniped pups indicating the importance of maternal transfer of these toxicants. As N. cinerea are endangered and recent declines in pup production has been reported for A. p. doriferus at the colony sampled, investigation of potential health impacts of these toxicants on Australian pinnipeds is recommended.

The fate of poly- and perfluoroalkyl substances in a marine food web influenced by land-based sources in the Norwegian Arctic

Although poly- and perfluorinated alkyl substances (PFAS) are ubiquitous in the Arctic, their sources and fate in Arctic marine environments remain unclear. Herein, abiotic media (water, snow, and sediment) and biotic media (plankton, benthic organisms, fish, crab, and glaucous gull) were sampled to study PFAS uptake and fate in the marine food web of an Arctic Fjord in the vicinity of Longyearbyen (Svalbard, Norwegian Arctic). Samples were collected from locations impacted by a firefighting training site (FFTS) and a landfill as well as from a reference site. Mean concentration in the landfill leachate was 643 ± 84 ng L^-1, while it was 365 ± 8.0 ng L^-1 in a freshwater pond and 57 ± 4.0 ng L^-1 in a creek in the vicinity of the FFTS. These levels were an order of magnitude higher than in coastal seawater of the nearby fjord (maximum level , at the FFTS impacted site). PFOS was the most predominant compound in all seawater samples and in freshly fallen snow (63-93% of ). In freshwater samples from the Longyear river and the reference site, PFCA ≤ C₉ were the predominant PFAS (37-59%), indicating that both local point sources and diffuse sources contributed to the exposure of the marine food web in the fjord. concentrations increased from zooplankton (1.1 ± 0.32 μg kg^-1 ww) to polychaete (2.8 ± 0.80 μg kg^-1 ww), crab (2.9 ± 0.70 μg kg^-1 ww whole-body), fish liver (5.4 ± 0.87 μg kg^-1 ww), and gull liver (62.2 ± 11.2 μg kg^-1). PFAS profiles changed with increasing trophic level from a large contribution of 6:2 FTS, FOSA and long-chained PFCA in zooplankton and polychaetes to being dominated by linear PFOS in fish and gull liver. The PFOS isomer profile (branched versus linear) in the active FFTS and landfill was similar to historical ECF PFOS. A similar isomer profile was observed in seawater, indicating major contribution from local sources. However, a PFOS isomer profile enriched by the linear isomer was observed in other media (sediment and biota). Substitutes for PFOS, namely 6:2 FTS and PFBS, showed bioaccumulation potential in marine invertebrates. However, these compounds were not found in organisms at higher trophic levels.

Revisiting old lessons from classic literature on persistent global pollutants : This article belongs to Ambio's 50th Anniversary Collection. Theme: Environmental contaminants

Looking back 50 years at classic literature was a reminder of inspiring discoveries and clever theories that were formative to the field of environmental chemistry, but also of the irreparable costs that persistent global pollutants have had on ecosystems and human society. In my view, these three papers have greatly impacted contemporary science and influenced development of policies that have limited the spread of hazardous contaminants. At the same time, a sobering reality is that reversing decades of past pollution has proven impossible in our lifetime, and global trends are dire for both legacy and emerging contaminants. Lessons in these papers are clear to most environmental scientists, but I argue have not resulted in adequate investment in infrastructure or manpower to enable systematic unbiased searching for pollutants as proposed by Sören Jensen in 1972. Acknowledging that the costs of new global contaminants will be too high, we must incentivize safer chemicals and their sustainable use, increase international exchange of lists of chemicals in commerce, and coordinate international efforts in nontarget screening to identify new contaminants before they circulate the world.

Fire Suppression Agents Combined with Gasoline in Aquatic Ecosystems: A Mixture Approach

Fire suppression agents are recommended for extinguishing fires by flammable liquids and frequently end in water bodies, combined with the fuels. There is a lack of toxicity information on these commercial formulations and the effects of mixtures of fire suppression agents and fuels. The aim of the present study was to evaluate the toxic effects of different fire suppression agents, the gasoline water-soluble fraction (GWSF), and mixtures of each fire suppression agent and GWSF. Individual tests were performed with Daphnia similis and Artemia sp.; the most toxic fire suppression agents to D. similis and Artemia sp. were F-500®, Cold Fire®, Agefoam®, and Kidde Sintex® 1%; the GWSF was the least toxic. The concentration addition model was used to predict the mixture effects and evaluate synergism/antagonism, dose ratio dependence, and dose level dependence. Cold Fire with GWSF showed dose level deviation to D. similis, marked mainly by synergism; for Artemia sp., the dose ratio pattern was predicted, with a synergistic response mainly by Cold Fire. Agefoam and GWSF behaved additively for D. similis and dose ratio for Artemia sp., with synergism being caused by Agefoam. Kidde Sintex 1% with GWSF were dose ratio for both organisms, with Kidde Sintex 1% being responsible for synergism. Our results show that some mixtures of fire suppression agents and GWSF may cause toxicity to aquatic organisms, posing risk in a real environmental scenario, such as a major fire combat. Environ Toxicol Chem 2021;40:767-779. © 2020 SETAC.

Effectiveness of household water purifiers in removing perfluoroalkyl substances from drinking water

Drinking water is one of the major exposure routes to Perfluoroalkyl substances (PFASs). These chemicals are scarcely removed by the conventional process in water purification plants. In the present study, four models of pitcher-type water purifiers (A-D) were tested to evaluate their removal effect on six PFASs including PFOS and PFOA. All of the water purifiers removed PFASs, but the efficiency was dependent on the models. Model C was most effective; more than 90% of all PFASs were removed through the recommended life of the filter cartridge. Model D was least effective; its removal efficiency declined below 50% by the end of the cartridge's life. When compared by the carbon chain length of PFASs, the removal efficiency was "C₁₂ > C₁₀ > C₈ > C₆" in all models. This study clearly demonstrates that household water purifiers are effective in decreasing the exposure to PFASs through drinking water.

Dual-Functional Phosphorene Nanocomposite Membranes for the Treatment of Perfluorinated Water: An Investigation of Perfluorooctanoic Acid Removal via Filtration Combined with Ultraviolet Irradiation or Oxygenation

Nanomaterials with tunable properties show promise because of their size-dependent electronic structure and controllable physical properties. The purpose of this research was to develop and validate environmentally safe nanomaterial-based approach for treatment of drinking water including removal and degradation of per- and polyfluorinated chemicals (PFAS). PFAS are surfactant chemicals with broad uses that are now recognized as contaminants with a significant risk to human health. They are commonly used in household and industrial products. They are extremely persistent in the environment because they possess both hydrophobic fluorine-saturated carbon chains and hydrophilic functional groups, along with being oleophobic. Traditional drinking water treatment technologies are usually ineffective for the removal of PFAS from contaminated waters, because they are normally present in exiguous concentrations and have unique properties that make them persistent. Therefore, there is a critical need for safe and efficient remediation methods for PFAS, particularly in drinking water. The proposed novel approach has also a potential application for decreasing PFAS background levels in analytical systems. In this study, nanocomposite membranes composed of sulfonated poly ether ether ketone (SPEEK) and two-dimensional phosphorene were fabricated, and they obtained on average 99% rejection of perfluorooctanoic acid (PFOA) alongside with a 99% removal from the PFOA that accumulated on surface of the membrane. The removal of PFOA accumulated on the membrane surface achieved 99% after the membranes were treated with ultraviolet (UV) photolysis and liquid aerobic oxidation.

Stranded cetaceans warn of high perfluoroalkyl substance pollution in the western Mediterranean Sea

Perfluoroalkyl substances (PFASs) are a class of organohalogenated compounds of environmental concern due to similar characteristics as the well-studied legacy persistent organic pollutants (POPs) that typically show environmental persistence, biomagnification and toxicity. Nevertheless, PFAS are still poorly regulated internationally and in many aspects poorly understood. Here, we studied liver and muscle concentrations in five cetacean species stranded at the southeastern coast of Spain during 2009-2018. Twelve of the fifteen targeted compounds were detected in >50% of the liver samples. Hepatic concentrations were significantly higher than those in muscle reflecting the particular toxicokinetics of these compounds. Bottlenose dolphins Tursiops truncatus showed the highest hepatic ΣPFAS (n = 5; 796.8 ± 709.0 ng g^-1 ww) concentrations, followed by striped dolphin Stenella coeruleoalba (n = 29; 259.5 ± 136.2 ng g^-1 ww), sperm whale Physeter macrocephalus (n = 1; 252.8 ng g^-1 ww), short-beaked common dolphin Delphinus delphis (n = 2; 240.3 ± 218.6 ng g^-1 ww) and Risso's dolphin Grampus griseus (n = 1; 78.7 ng g^-1 ww). These interspecies differences could be partially explained by habitat preferences, although they could generally not be related to trophic position or food chain proxied by stable N (δ¹⁵N) and C (δ¹³C) isotope values, respectively. PFAS profiles in all species showed a similar pattern of concentration prevalence in the order PFOS>PFOSA>PFNA≈PFFUnA>PFDA. The higher number of samples available for striped dolphin allowed for evaluating their PFAS burden and profile in relation to the stranding year, stable isotope values, and biological variables including sex and length. However, we could only find links between δ¹⁵N and PFAS burdens in muscle tissue, and between stranding year and PFAS profile composition. Despite reductions in the manufacturing industry, these compounds still appear in high concentrations compared to more than two decades ago in the Mediterranean Sea and PFOS remains the dominating compound.

Perfluoroalkyl acids and sulfonamides and dietary, biological and ecological associations in peregrine falcons from the Laurentian Great Lakes Basin, Canada

Perfluoroalkyl substances (PFAS) are a large, diverse group of chemicals and several perfluoroalkyl acids (PFAAs) are known environmental contaminants. Wildlife exposure to PFAAs and precursors has been shown, but less is known regarding replacements such as shorter-chain PFAS. In the present study, exposure to a suite of PFAAs and associations with dietary, biological and ecological factors were investigated in populations of a sentinel apex species - the peregrine falcon (Falco peregrinus). Nestling blood (n = 57) and sibling eggs (n = 9) were sampled in 2016 and 2018 from nests in rural and urban regions across the Laurentian Great Lakes Basin, Canada. PFSAs (perfluorinated sulfonic acids) including PFHxS, PFOS, and PFDS were detected in most egg and plasma samples, whereas 11 PFCAs (perfluorinated carboxylic acids; C₅-C₁₄, C₁₆) compared to eight PFCAs (C₈-C₁₄, C₁₆) were detected in most eggs and plasma, respectively. Shorter-chain C₈-C₁₀ PFCAs were more dominant in plasma and longer-chain C₁₂-C₁₄ PFCAs in eggs, but profiles were similar for PFOS, PFDS, PFUdA and PFHxDA. The exposure to PFAAs in peregrine falcons is likely mediated by dietary factors such as foraging location (δ¹³C and δ³⁴S) and trophic position (δ¹⁵N) given the associations observed in eggs and nestling plasma, respectively. Moreover, significant relationships were observed for circulating ΣPFCAs and region (rural/urban), and nestling body condition after adjusting for sampling year and dietary tracers, suggesting that compared to rural nestlings, urban nestlings may be more exposed to ΣPFCAs and prone to their potential physiological impacts. Our findings highlight the importance of integrating dietary, biological and ecological factors when studying PFAS exposure in birds.

Deterministic risk assessment of firefighting water additives to aquatic organisms

Past firefighting water additives were found to contain perfluorinated compounds that could persist in the environment resulting in potential adverse effects to biota. Since this revelation, manufacturers have introduced alternative firefighting water additives that are fluorine free, but few studies have investigated the fate and effects in the environment of these new additives. Firefighting water additives could enter aquatic ecosystems through run-off, leaching or direct application. Therefore, there is a need to investigate the potential effect that firefighting water additives could have on aquatic biota. This study investigated the toxicity of six firefighting water additives: Eco-Gel™, Thermo-Gel™, FireAde™, Fire-Brake™, Novacool Foam™, and F-500™ to aquatic biota. The toxicities of firefighting water additives to Lemna minor (duckweed), Daphnia magna (water flea), Hexagenia spp. larvae (mayfly), Lampsilis fasciola (wavy-rayed lampmussel) and Oncorhynchus mykiss (rainbow trout) were investigated through acute and chronic static and semi-static tests to estimate LC50 values for survival and EC50 values for immobility and/or reproduction endpoints. A large variation in toxicities among the firefighting water additives and among the test species was observed. Based on a worst-case exposure scenario of direct application, several firefighting water additives were found to pose a hazard to aquatic organisms. An exposure rate representative of a direct overhead application by a water bomber during a forest fire was used in the hazard assessment. For example, the hazard quotients determined for the D. magna acute toxicity tests ranged from 0.20 for Eco-Gel to 317 for F-500 in the forest pool (15 cm) scenario. This study presents the first deterministic risk assessment of firefighting water additives in aquatic ecosystems.

PFAS Environmental Pollution and Antioxidant Responses: An Overview of the Impact on Human Field

Due to their unique properties, perfluorinated substances (PFAS) are widely used in multiple industrial and commercial applications, but they are toxic for animals, humans included. This review presents some available data on the PFAS environmental distribution in the world, and in particular in Europe and in the Veneto region of Italy, where it has become a serious problem for human health. The consumption of contaminated food and drinking water is considered one of the major source of exposure for humans. Worldwide epidemiological studies report the negative effects that PFAS have on human health, due to environmental pollution, including infertility, steroid hormone perturbation, thyroid, liver and kidney disorders, and metabolic disfunctions. In vitro and in vivo researches correlated PFAS exposure to oxidative stress effects (in mammals as well as in other vertebrates of human interest), produced by a PFAS-induced increase of reactive oxygen species formation. The cellular antioxidant defense system is activated by PFAS, but it is only partially able to avoid the oxidative damage to biomolecules.

Exposure to Perflouroalkyl acids and foetal and maternal thyroid status: a review

BACKGROUND

Exposure to perfluorinated-alkyl-acids (PFAAs) is ubiquitous. PFAAs are hormone-disrupting compounds that are strongly suspected to affect mother-child-health such as fetal growth. Thyroid disruption is a plausible mechanism of action. We aim to summarize the epidemiological evidence for the relation between prenatal and postnatal exposure to PFAAs and disruption of thyroid homeostasis in mothers and/or infants.

METHOD

Fifteen original publications on PFAAs concentrations and thyroid hormones (TH) in pregnant women and/or infants were found upon a literature search in the PubMed database. Information on exposure to seven PFAAs congeners [Perfluorooctane sulfonate (PFOS), Perfluorooctanoate (PFOA), Perfluorohexane sulfonate (PFHxS), Perfluorononanoic acid (PFNA), Perfluorodecanoic acid (PFDA), Perfluoroundecanoic acid (PFUnA), and Perfluorododecanoic acid (PFDoA)] and thyroid stimulating hormone (TSH), free and total thyroxine (FT4 and TT4), free and total triiodothyronine (FT3 and TT3), T3RU (Free triiodothyronine resin uptake) and FT4-index (FT4I) levels were recorded. We evaluated sampling of maternal TH by trimester, and infant TH by sex stratification. Reported associations between mother or infant PFAAs and TH were not uniformly assessed in the selected studies.

RESULTS

Ten out of the fifteen studies examined maternal PFAAs concentration and TSH level. Seven studies showed significant associations between TSH and exposure to six PFAAs congeners, most of them were positive. Maternal T4 and T3 were investigated in nine studies and five studies found inverse associations between exposure to six PFAAs congeners and TH (TT3, TT4, FT3, FT4 and FT4I) levels. Eight of the fifteen studies investigated PFAAs concentrations and infant TSH. Infant TSH level was significantly affected in four studies, positively in three studies. Nine studies investigated infant T4 and T3 and seven studies found significant associations with PFAAs exposure. However, both inverse and positive significant associations with infant TH were found eliciting no clear direction.

CONCLUSION

Results indicate a mainly positive relationship between maternal PFAAs concentrations and TSH levels, and suggestion of an inverse association with T4 and/or T3 levels. Associations of infant TH with PFAAs concentration were less consistent.

Effects of the UV filter, oxybenzone, adsorbed to microplastics in the clam Scrobicularia plana

Microplastics (MPs) lipophilic nature and widespread distribution raises concerns due to their increasing presence in the marine environment and their ability to adsorb organic contaminants, as being potential vehicles for transport and potential source of accumulation of organic contaminants by marine organisms. The organic UV-filter, oxybenzone (BP-3) is a constituent of sunscreens and personal care products, entering the marine environment either by direct contact with swimmers or by wastewater effluents. In this study the ecotoxicological effects of exposure to low-density polyethylene (LDPE) microplastics with and without adsorbed BP-3 were investigated in the peppery furrow shell clam, Scrobicularia plana. LDPE microplastics with a size range of 11-13 μm were previously contaminated with an environmentally relevant concentration of BP-3 (82 ng g^-1). S. plana individuals were exposed to a concentration of 1 mg L^-1 of microplastics with and without BP-3 adsorbed in a water-sediment exposure system for 14 days. Clams were sampled at the beginning of the experiment and after 3, 7, and 14 days of exposure. Multiple biomarkers were analysed to investigate the effect of exposure in different clam tissues, gills, digestive gland, and haemolymph. Antioxidant (superoxide dismutase, catalase, glutathione peroxidase) and biotransformation (glutathione-S-transferases) enzyme activities, oxidative damage (lipid peroxidation), genotoxicity (single and double strand DNA breaks), and neurotoxicity (acetylcholinesterase activity) were assessed along with two biomarker indexes to assess the overall health status. Results indicate that after 7 days of exposure MPs with adsorbed BP-3 induced oxidative stress and damage, when compared to exposure to virgin MPs and control treatments. Neurotoxic effects were also noted in MPs with adsorbed BP-3 after 14 days exposure, while some evidence points to increased genotoxicity with exposure time. Overall results indicate that gills were more affected by exposure to microplastics than digestive gland and that biomarkers alterations are apparently more related to the toxicity of BP-3 adsorbed than virgin MPs alone.

On the Role of the Cathode for the Electro-Oxidation of Perfluorooctanoic Acid

Perfluorooctanoic acid (PFOA), C7F15COOH, has been widely employed over the past fifty years, causing an environmental problem because of its dispersion and low biodegradability. Furthermore, the high stability of this molecule, conferred by the high strength of the C-F bond makes it very difficult to remove. In this work, electrochemical techniques are applied for PFOA degradation in order to study the influence of the cathode on defluorination. For this purpose, boron-doped diamond (BDD), Pt, Zr, and stainless steel have been tested as cathodes working with BDD anode at low electrolyte concentration (3.5 mM) to degrade PFOA at 100 mg/L. Among these cathodic materials, Pt improves the defluorination reaction. The electro-degradation of a PFOA molecule starts by a direct exchange of one electron at the anode and then follows a complex mechanism involving reaction with hydroxyl radicals and adsorbed hydrogen on the cathode. It is assumed that Pt acts as an electrocatalyst, enhancing PFOA defluorination by the reduction reaction of perfluorinated carbonyl intermediates on the cathode. The defluorinated intermediates are then more easily oxidized by HO• radicals. Hence, high mineralization (xTOC: 76.1%) and defluorination degrees (xF−: 58.6%) were reached with Pt working at current density j = 7.9 mA/cm2. This BDD-Pt system reaches a higher efficiency in terms of defluorination for a given electrical charge than previous works reported in literature. Influence of the electrolyte composition and initial pH are also explored.

Perfluoroalkyl substances in sediments from the Bering Sea to the western Arctic: Source and pathway analysis

Although perfluoroalkyl substances (PFASs) are ubiquitous in the Arctic, their dominant pathways to the Arctic remain unclear. Most modeling studies support major oceanic transport for PFASs in the Arctic seawater, but this conclusion contradicts the rapid response of PFASs to global emissions in some biota species. Sediments, which act as important PFAS sinks for seawater and potential PFAS source to the benthic food web, are important for interpreting the fate of PFASs in the Arctic. Here we investigate the occurrence of 9 PFASs in one core (1945-2014) and 29 surface sediments from the Bering Sea to the western Arctic. Total PFAS concentrations (0.06-1.73 ng/g dw) in surface sediments were dominated by perfluorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA) and perfluorobutyl sulfonate (PFBS), with higher levels in the Bering Sea slope and the northeast Chukchi Sea. Historical trends in PFASs varied among individuals, with PFOS declining in the early 2000s while PFNA showing an increasing up-core trend. Analysis of positive matrix factorization model identified that the major PFAS sources in the sediment core were dominated by the atmospheric oxidation of consumer use of PFOS precursor-based products (45.0%), while the oceanic transport of fluoropolymer manufacture of polyvinylidene fluoride (mainly PFNA) exhibited an increasing trend over time, becoming dominant in surface sediments (42.8%). Besides, local input of possible aqueous fire-fighting foams (mainly PFOS and PFBS) also acted as an important source currently (30.1%) and historically (34.9%). Our study revealed that the pathways of PFASs in Arctic sediments varied greatly for individuals and the conclusion of PFOS originating from mainly atmospheric oxidation was different from seawater modeling results. This, together with the high possibility of sediments as direct source to Arctic food web (supported by similar PFAS compositions and temporal variations), help provide additional evidence regarding PFAS pathways to the Arctic.

Spatiotemporal Analysis of Perfluoroalkyl Substances in White-Tailed Eagle (Haliaeetus albicilla) Nestlings from Northern Norway-A Ten-Year Study

The white-tailed eagle (Haliaeetus albicilla) in Scandinavia has suffered from impaired reproduction due to high exposure to industrial pollution between the 1960s and 1980s. While population numbers are rising again, new contaminants, such as per- and polyfluoroalkyl substances (PFAS), are increasingly found in high trophic avifauna and are of concern to potentially impact once again on population health. In the present study, we examined PFAS levels in plasma of white-tailed eagle nestlings from northern Norway over the last decade (2008-2017). While PFOA and PFNA exposure did not follow a significant time trend, PFOS and PFHxS concentrations decreased over time, and ≥C₁₁ perfluorinated carboxylic acids only seem to level off during the last four years. This may in fact be the first evidence for a change in the trend for some of these compounds. Furthermore, since several PFAS are expected to be highly present in aqueous film-forming foams used at airports, we also investigate the potential of the two main airports in the region to act as hotspots for PFAS. Our results indeed show decreasing exposure to PFOA with distance to the airports. Altogether, our results seem to show that legislation actions are effective, and continued concern for PFAS exposure of high trophic wildlife is still warranted, even in the northern environment.

Fluorine Mass Balance and Suspect Screening in Marine Mammals from the Northern Hemisphere

There is increasing evidence that the ∼20 routinely monitored perfluoroalkyl and polyfluoroalkyl substances (PFASs) account for only a fraction of extractable organofluorine (EOF) occurring in the environment. To assess whether PFAS exposure is being underestimated in marine mammals from the Northern Hemisphere, we performed a fluorine mass balance on liver tissues from 11 different species using a combination of targeted PFAS analysis, EOF and total fluorine determination, and suspect screening. Samples were obtained from the east coast United States (US), west and east coast of Greenland, Iceland, and Sweden from 2000 to 2017. Of the 36 target PFASs, perfluorooctane sulfonate (PFOS) dominated in all but one Icelandic and three US samples, where the 7:3 fluorotelomer carboxylic acid (7:3 FTCA) was prevalent. This is the first report of 7:3 FTCA in polar bears (∼1000 ng/g, ww) and cetaceans (<6-190 ng/g, ww). In 18 out of 25 samples, EOF was not significantly greater than fluorine concentrations derived from sum target PFASs. For the remaining 7 samples (mostly from the US east coast), 30-75% of the EOF was unidentified. Suspect screening revealed an additional 37 PFASs (not included in the targeted analysis) bringing the total to 63 detected PFASs from 12 different classes. Overall, these results highlight the importance of a multiplatform approach for accurately characterizing PFAS exposure in marine mammals.