Polyfluorinated chemicals in a spatially and temporally integrated food web in the Western Arctic

Less is more: a methodological assessment of extraction techniques for per- and polyfluoroalkyl substances (PFAS) analysis in mammalian tissues

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants. Studying the bioaccumulation in mammalian tissues requires a considerable effort for the PFAS extraction from complex biological matrices. The aim of the current work was to select and optimize the most efficient among common extraction strategies for eleven perfluoroalkyl acids (PFAA). Primary extractions from wild boar tissues (liver, kidney, and lung) were performed with methanol at neutral, acidic, or alkaline conditions, or with methyl-tert-butyl ether (MTBE) after ion-pairing with tetrabutylammonium (TBA) ions. A second purification step was chosen after comparing different solid-phase extraction (SPE) cartridges (Oasis WAX, ENVI-Carb, HybridSPE Phospholipid) and various combinations thereof or dispersive SPE with C18 and ENVI-Carb material. The best extraction efficiencies of the liquid PFAA extraction from tissue homogenates were achieved with methanol alone (recoveries from liver 86.6-114.4%). Further purification of the methanolic extracts using dispersive SPE or Oasis WAX columns decreased recoveries of most PFAA, whereas using pairs of two SPE columns connected in series proved to be more efficient albeit laborious. Highest recoveries for ten out of eleven PFAA were achieved using ENVI-Carb columns (80.3-110.6%). In summary, the simplest extraction methods using methanol and ENVI-Carb columns were also the most efficient. The technique was validated and applied in a proof of principle analysis in human tissue samples.

Analytical approaches for screening of per- and poly fluoroalkyl substances in food items: A review of recent advances and improvements

Per and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals characterized by their ubiquitous nature in all environmental compartments which makes them of increasing concern due to their persistence, bioaccumulation, and toxicity (PBT). Several instrumental methodologies and separation techniques have been identified in the literature for the detection and quantification of PFAS in environmental samples. In this review, we have identified and compared common separation techniques adopted for the extraction of PFAS in food items, and analytical methodologies for identification and quantification of PFAS in food items of plant and animal origin, highlighting recent advances in tandem techniques for the high selectivity and separation of PFAS related compounds as well as knowledge gaps and research needs on current analytical methodologies.

Trophic behaviors of PFOA and its alternatives perfluoroalkyl ether carboxylic acids (PFECAs) in a coastal food web

With the increasing restrictions and concerns about legacy poly- and perfluoroalkyl substances (PFAS), the production and usage of alternatives, i.e., perfluoroalkyl ether carboxylic acids (PFECAs), have risen recently. However, there is a knowledge gap regarding the bioaccumulation and trophic behaviors of emerging PFECAs in coastal ecosystems. The bioaccumulation and trophodynamics of perfluorooctanoic acid (PFOA) and its substitutes (PFECAs) were investigated in Laizhou Bay, which is located downstream of a fluorochemical industrial park in China. Hexafluoropropylene oxide trimer acid (HFPO-TrA), perfluoro-2-methoxyacetic acid (PFMOAA) and PFOA constituted the dominant compounds in the ecosystem of Laizhou Bay. PFMOAA was dominant in invertebrates, whereas the long-chain PFECAs preferred to accumulate in fishes. The PFAS concentrations in carnivorous invertebrates were higher than those in filter-feeding species. Considering migration behaviors, the ∑PFAS concentrations followed the order oceanodromous fish < diadromous fish < non-migratory fish. The trophic magnification factors (TMFs) of long-chain PFECAs (HFPO-TrA, HFPO-TeA and PFO5DoA) were >1, suggesting trophic magnification potential, while biodilution for short-chain PFECAs (PFMOAA) was observed. The intake of PFOA in seafood may constitute a great threat to human health. More attention should be given to the impact of emerging hazardous PFAS on organisms for the health of ecosystems and human beings.

The Need for Testing Isomer Profiles of Perfluoroalkyl Substances to Evaluate Treatment Processes

Many environmentally relevant poly-/perfluoroalkyl substances (PFASs) including perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) exist in different isomeric (branched and linear) forms in the natural environment. The isomeric distribution of PFASs in the environment and source waters is largely controlled by the source of contamination and varying physicochemical properties imparted by their structural differences. For example, branched isomers of PFOS are relatively more reactive and less sorptive compared to the linear analogue. As a result, the removal of branched and linear PFASs during water treatment can vary, and thus the isomeric distribution in source waters can influence the overall efficiency of the treatment process. In this paper, we highlight the need to consider the isomeric distribution of PFASs in contaminated matrices while designing appropriate remediation strategies. We additionally summarize the known occurrence and variation in the physicochemical properties of PFAS isomers influencing their detection, fate, toxicokinetics, and treatment efficiency.

Analysis of Per- and Poly(fluoroalkyl) Substances (PFASs) in Highly Consumed Seafood Products from U.S. Markets

Seafood consumption has been identified as one of the major contributors of per- and poly(fluoroalkyl) substances (PFASs) to the human diet. To assess dietary exposure, highly consumed seafood products in the United States were selected for analysis. The analytical method previously used for processed food was extended to include four additional long-chain perflurocarboxylic acids (PFCAs), which have been reported in seafood samples. This method was single-lab-validated, and method detection limits were reported at 345 ng kg^-1 for perfluorobutanoic acid (PFBA) and 207 ng kg^-1 for perfluoropentanoic acid (PFPeA) and below 100 ng kg^-1 for the rest of the PFAS analytes. The 81 seafood samples (clams, crab, tuna, shrimp, tilapia, cod, salmon, pollock) were analyzed for 20 PFASs using the updated analytical method. Most of the seafood packaging was also analyzed by Fourier transform infrared-attenuated total reflectance (FTIR-ATR) to identify packaging potentially coated with PFASs. None of the packaging samples in this study were identified as having PFASs. A wide range of concentrations was observed among the seafood samples, ranging from below the method detection limit to the highest concentration of 23 μg kg^-1 for the sum of PFASs in one of the canned clam samples. Such a wide range is consistent with those reported in previous studies. The highest concentrations were reported in clams and crabs, followed by cod, tuna, pollock, tilapia, salmon, and shrimp. Technical perfluorooctanoic acid (PFOA) dominated the profile of the clam samples, which has been consistently found in other clam samples, especially in Asia. Long-chain PFCAs, specifically perfluoroundecanoic (PFUdA) and perfluorododecanoic (PFDoA), were the most frequently detected analytes across all seafood samples. The trends observed are comparable with those in the literature where benthic organisms tend to have the highest PFAS concentrations, followed by lean fish, fatty fish, and aquaculture. The results from this study will be used to prioritize future studies and to inform steps to reduce consumer exposure to PFASs.

Widespread Occurrence of Non-Extractable Fluorine in Artificial Turfs from Stockholm, Sweden

Per- and polyfluoroalkyl substances (PFAS) are frequently used in the production of rubber and plastic, but little is known about the identity, concentration, or prevalence of PFAS in these products. In this study, a representative sample of plastic- and rubber-containing artificial turf (AT) fields from Stockholm, Sweden, was subjected to total fluorine (TF), extractable organic fluorine (EOF), and target PFAS analysis. TF was observed in all 51 AT samples (ranges of 16-313, 12-310, and 24-661 μg of F/g in backing, filling, and blades, respectively), while EOF and target PFAS occurred in <42% of all samples (<200 and <1 ng of F/g, respectively). A subset of samples extracted with water confirmed the absence of fluoride. Moreover, application of the total oxidizable precursor assay revealed negligible perfluoroalkyl acid (PFAA) formation across all three sample types, indicating that the fluorinated substances in AT are not low-molecular weight PFAA precursors. Collectively, these results point toward polymeric organofluorine (e.g., fluoroelastomer, polytetrafluoroethylene, and polyvinylidene fluoride), consistent with patent literature. The combination of poor extractability and recalcitrance toward advanced oxidation suggests that the fluorine in AT does not pose an imminent risk to users. However, concerns surrounding the production and end of life of AT, as well as the contribution of filling and blades to environmental microplastic contamination, remain.

First Report on the Bioaccumulation and Trophic Transfer of Perfluoroalkyl Ether Carboxylic Acids in Estuarine Food Web

As novel alternatives to legacy poly- and perfluoroalkyl substances (PFAS), perfluoroalkyl ether carboxylic acids (PFECAs) have been widely detected in the environment; however, there is limited information and knowledge regarding their bioaccumulation and trophic transfer behavior along the food chain. This research presents the first known published data on the bioaccumulation and trophic transfer characteristics of PFECAs in a source-impacted estuary. Elevated PFECA concentrations were observed in organisms (for instance, conch, with perfluoro-2-methoxyacetic acid (PFMOAA) concentration reaches up to 16 700 ng/g dry weight (dw)), indicating exposure risks to the consumers. Conch can be acted as a potential environmental bioindicator of PFMOAA. PFMOAA, hexafluoropropylene oxide trimer acid (HFPO-TrA) and PFOA were predominant detected in biotas. On the basis of trophic magnification factors (TMFs), PFECAs with ≥6 perfluorinated carbons (HFPO-TrA, hexafluoropropylene oxide tetramer acid (HFPO-TeA) and perfluoro (3, 5, 7, 9, 11-pentaoxadodecanoic) acid (PFO5DoA)) could be biomagnified along the food chain (TMF > 1), while PFMOAA with the least perfluorinated carbons undergone biodilution (TMF < 1). As seafood is an important dietary source of protein to human, there is a potential health risk related to the consuming polluted aquatic products.

Global performance and trends of research on per- and polyfluoroalkyl substances (PFASs) between 2001 and 2018 using bibliometric analysis

Per- and polyfluoroalkyl substances (PFASs) are widely used in food packaging, non-stick pots, and surfactants. However, their persistence in the environment, hazardous nature, and potential for bioaccumulation and long-range transport have alarmed an increasing number of scholars and research institutions. Although several literature reviews on PFASs research exist, only a few of them have considered bibliometric indices. In this study, 3,373 PFASs-related articles published between 2001 and 2018 were analyzed using a bibliometric analysis method based on the Science Citation Index (SCI) Expanded. The software tools for mapping knowledge domain (MKD) (VOSviewer and Science of Science (Sci2)) were used to analyze the performance of contributors and PFASs research topics, hotspots, and trends. Our results reveal that the number of PFASs-related articles published annually has increased significantly, with most originating from the United States (followed by those from China). The Chinese Academy of Sciences has published the most articles. A comprehensive analysis of title, keywords, and keywords plus showed that PFASs research hotspots include humans, precursors, and detection methods, with the main focuses being environmental science, toxicology, and environmental engineering. The four main research topics of PFASs were identified, and a literature review was carried out for each one. Overall, this study can supply researchers with a deeper understanding of the development of PFASs studies and provide a comprehensive data reference for researchers to further grasp the research direction in this field.

Investigation of levels of perfluoroalkyl substances in freshwater fishes collected in a contaminated area of Veneto Region, Italy

The bioaccumulation of 12 perfluoroalkyl substances (PFASs) in 107 freshwater fishes collected during 2017 in waterbodies of a contaminated area in Veneto Region (Italy) was evaluated. The contamination had been previously ascribed to a fluorochemical manufacturing plant that discharged mainly perfluorooctanoic acid (PFOA), among other PFASs, into the surrounding environment. Perfluorooctane sulfonate (PFOS) was the most abundant compound, detected in almost 99% of the fish with an average concentration of 9.23 µg/kg wet weight (w/w). Other detected compounds were perfluoroundecanoic acid (PFUnA) (98%, 0.55 µg/kg w/w), perfluorodecanoic acid (PFDA) (98%, 2.87 µg/kg w/w), perfluorododecanoic acid (PFDoA) (93%, 1.51 µg/kg w/w), and PFOA (79%, 0.33 µg/kg w/w). Bioaccumulation of PFASs was species related, with Italian barbel being the most contaminated, followed by chub, wels catfish, and carp, reflecting animals' habitat use and feeding behavior. A significant negative linear relation between PFAS concentration and fish weight was observed no matter the considered species, with smaller fish having proportionally higher bioaccumulation. PFOS concentrations were strongly correlated with the concentrations of other PFASs, suggesting a similar source of contamination or a contamination from ubiquitous sources. Correlation analysis showed PFOA likely originated from a separated source, unlinked to other PFASs. Although the fishes studied are not usually consumed by local people, with the likely exception of freshwater anglers (and relatives), their consumption has been banned by Veneto Authority since the time this study was conducted. In fact, the study suggests that a medium/high consumption frequency (superior to 1 portion per month) of fish from the investigated area might result in a high exposure to PFASs.

Sorption and desorption kinetics of PFOS to pristine microplastic

The sorption processes of persistent organic pollutants on microplastics particles are poorly understood. Therefore, the present study investigated the sorption processes of perfluorooctanesulfonate (PFOS) on polyethylene (PE) microplastic particles (MPs) which are representing a prominent environmental pollutant and one of the most abundant microplastic polymers in the aquatic environment, respectively. The focus was set on the investigation of the impact of the particle size on PFOS sorption using four different PE MPs size ranges. The sorption kinetics for 6 months was studied with one selected size range of PE MPs. Besides, the desorption of PFOS from PE MPs under simulated digestive conditions was carried out by using artificial gut fluid mimicking the intestinal juice of fish. The investigation of the size effects of particles over 6 months demonstrated a linear increase of PFOS concentration sorbed onto PE with a decrease of the particle size. Thus, our findings implicate efficient sorption of PFOS onto PE MPs of different sizes. The results showed that PFOS desorbed from the PE MPs into the artificial gut fluid with a rate of 70 to 80%. Besides, a longer exposure of PE MPs to PFOS leads to a higher concentration adsorbed by PE MPs, which may favor the ingestion of higher concentration of PFOS, and thus represents a higher risk to transfer relevant concentrations of PFOS during digestion.

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.

Legacy and emerging per- and polyfluorinated alkyl substances (PFASs) in sediment and edible fish from the Eastern Red Sea

POLY: and perfluorinated alkyl substances (PFASs) are ubiquitously detected all around the world. Herein, for the first time, concentrations of 16 selected legacy and emerging PFASs are reported for sediment and edible fish collected from the Saudi Arabian Red Sea. Mean concentrations varied from 0.57 to 2.6 μg kg^-1 dry weight (dw) in sediment, 3.89-7.63 μg kg^-1 dw in fish muscle, and 17.9-58.5 μg kg^-1 dw in fish liver. Wastewater treatment plant effluents represented the main source of these compounds and contributed to the exposure of PFAS to biota. Perfluorooctane sulfonate (PFOS) was the most abundant compound in sediment and fish tissues analysed, comprising between 42 and 99% of the ∑₁₆PFAS. The short chain perfluorobutanoate (PFBA) was the second most dominant compound in sediment and was detected at a maximum concentration of 0.64 μg kg^-1 dw. PFAS levels and patterns differed between tissues of investigated fish species. Across all fish species, ∑₁₆PFAS concentrations in liver were significantly higher than in muscle by a factor ranging from 3 to 7 depending on fish species and size. The PFOS replacements fluorotelomer sulfonate (6:2 FTS) and perfluorobutane sulfonate (PFBS) exhibited a bioaccumulation potential in several fish species and 6:2 FTS, was detected at a maximum concentration of 7.1 ± 3.3 μg kg^-1 dw in a doublespotted queenfish (Scomberoides lysan) liver. PFBS was detected at a maximum concentration of 2.65 μg kg^-1 dw in strong spine silver-biddy (Gerres longirostris) liver. The calculated dietary intake of PFOS, perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorohexane sulfonic acid (PFHxS) exceeded the safety threshold established by the European Food Safety Authority (EFSA) in 2020 in doublespotted queenfish muscle, indicating a potential health risk to humans consuming this fish in Jeddah, Saudi Arabia.

Perfluorooctane sulfonate promotes doxycycline-induced liver tumor progression in male Krasv12 transgenic zebrafish

Perfluorooctane sulfonate (PFOS) is a persistent organic pollutant that has been widely detected in the environment and has caused growing international concern. The liver is the main target organ of PFOS exposure. Animal experiments have shown that PFOS exposure can increase the risk of liver tumorigenesis. However, whether PFOS can accelerate liver tumor progression is still unclear. In this study, transgenic zebrafish Tg(fabp10:rtTA2s-M2; TRE2:EGFP-KRAS^G12V), a hepatocellular carcinoma (HCC) model that can cause liver tumorigenesis by doxycycline (DOX) induction, was used to investigate the effect of PFOS exposure in HCC progression. The male kras^V12 transgenic zebrafish were exposed to 20 mg/L DOX, 500 μg/L PFOS or combined 20 mg/L DOX and 500 μg/L PFOS for 10 d. The results showed that co-treated with PFOS and DOX caused oncogenic Kras-induced liver enlargement, increased the percentages of zebrafish with HCC, and aggravated metabolic reprogramming of liver. To the best of our knowledge, this study for the first proved that PFOS could promote liver tumor progression. Decreased vitamin D level and increased fatty acid intake caused by PFOS might be responsible for the tumor-promoting effects. The results suggest that attention should be paid to the tumor-promoting effects of PFOS when assessing its environmental health risks, and these findings provide new insights into the toxicity of PFOS.

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.

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.

Per- and polyfluoroalkyl substances (PFASs) in contaminated coastal marine waters of the Saudi Arabian Red Sea: a baseline study

Per- and polyfluoroalkyl substances (PFASs) are today considered important constituents of the continuously growing substance group of persistent contaminants of emerging environmental concern (PCEC). Here, we report for the first time the concentrations of 12 relevant PFASs in 28 marine water samples from the Saudi Arabian coastal waters of the Red Sea. The sum levels of 12 PFASs (Σ₁₂ PFAS) in surface seawater ranged from <LOQ to 956 ngL^-1. For the reference background site of this study, Σ₁₂ PFAS levels ranged from <LOQ to 10.9 ng/L. The highest PFAS levels have been found in Al-Arbaeen and Al-Shabab, two lagoons continuously receiving treated sewage effluents. PFHxA, PFHxS, and 6:2 FTS were the most prevalent PFASs with relatively high concentrations. Discharge of municipal and industrial wastewaters is considered an important source of PFASs. The pattern of PFASs observed here suggests that the usage of PFAS-containing aqueous film-forming foams (AFFFs) is a potential additional source for these compounds in Al-Arbaeen and Al-Shabab lagoons. However, a systematic elucidation of local PFASs sources is needed. Contamination of the Red Sea waters with PFASs poses a potential imminent risk to the marine environment of the Red Sea and ultimately may even affect the health of human consumers through the consumption of local seafood.

Exposure characteristics for congeners, isomers, and enantiomers of perfluoroalkyl substances in mothers and infants

Per- and polyfluoroalkyl substances (PFASs) are ubiquitous in the environment, making it inevitable for humans to be exposed to these pollutants. The exposure begins while in utero and continues in infancy, during the potentially most sensitive early stages of life. This review summarizes the current knowledge on pre- and neo-natal exposures based on more than 200 articles published from 2000 to date. All relevant biological matrices used in the cited studies were included, such as maternal blood, umbilical cord blood, breast milk, placenta, amniotic fluid, fetal organs, newborns' dried blood spots, and infant serum. We show that such exposures are geographically global with significant discrepancies among countries and continents, and that while the levels of major legacy PFASs (PFOS and PFOA) have declined since 2000, those of others may have not. We also show that levels of PFOS and PFOA exceed those of some major environmental toxins, such as p,p'-DDE, BDE-47, PCB-153, PBB-153, and OH-PBDEs in maternal blood. Given that the behavior and potential effects have an origin in molecular structure, biomonitoring and research at the levels of isomers and enantiomers are critically important. Through critical analysis of these works, we summarize the major achievements, consensus, and the deficiencies of existing research. To our knowledge, this is the first review on the overall internal exposure status of mothers and infants to PFASs during pregnancy and lactation.

Ecological and health risk assessment of perfluorooctane sulfonate in surface and drinking water resources in China

Perfluorooctane sulfonate (PFOS) is a synthetic substance with a great number of applications. However, it persists in the environment and is potentially toxic to organisms. Although China has been the main manufacturer and consumer for PFOS, the national pollution level and potential risk of this chemical are yet to be determined. This study aimed to provide an overview of PFOS contamination in surface and drinking water across China and to assess the potential ecological and health risks. Available monitoring data for PFOS in surface and drinking water were evaluated. PFOS was found to be ubiquitous in China, but the overall level of contamination was low compared with that in other countries. The southeast coastal area of China, with major PFOS-related companies, was characterized by relatively high PFOS exposure concentrations. The most sensitive effects was screened and applied to assess the ecological risk using the joint probability curve method. The probability of exceeding the growth and development toxicity for 5% of aquatic species was 0.65% in Chinese surface waters, while the highest probability of 0.90% was in Tai Lake in east China. Considering the average daily dose (ADD) for the Chinese population, the health risk posed by PFOS through drinking water ranged from 1.31 × 10^-4 to 13.91. Besides the relatively high health risk existed in east China, most health risks in China were acceptable.

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.

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.

Occurrence and trophic transfer of per- and polyfluoroalkyl substances in an Antarctic ecosystem

Information on the occurrence and trophodynamics of per- and polyfluoroalkyl substances (PFASs) in the Antarctic region is limited. We investigated the occurrence of PFASs in an ecosystem in the Fildes Peninsula at King George Island and Ardley Island, Antarctica. The profiles, spatial distribution, and trophic transfer behavior of PFASs were further studied. ∑PFASs ranged from 0.50 ± 38.0 ng/g dw (dry weight) in algae to 4.97 ± 1.17 ng/g dw in Neogastropoda (Ngas), which was lower than those in the low- and mid-latitude regions and even Arctic regions. Perfluorobutyric acid (PFBA) was predominant with detection frequencies above 50% in all types of samples, and the relative contribution of PFBA ranged from 22% to 57% in the biota samples. The biomagnification factors of PFBA, perfluoroheptanoate (PFHpA), perfluorohexane sulfonate (PFHxS), and perfluorooctane sulfonate (PFOS) between Archaeogastropoda (Agas) and Ngas were 0.67 ± 0.54, 0.77 ± 0.38, 1.04 ± 1.56, 3.30 ± 4.07, and 1.61 ± 0.89, respectively. The trophic magnification factors of PFHxS and PFOS were 2.09 and 2.92, respectively, which indicated that they could be biomagnified through the food chain. Considering the increasing production and uncertain toxicological risks of emerging PFASs and the sensitive ecosystems in Antarctic regions, more attention should be paid, especially for the short-chain ones in the Antarctic region.

Temporal variations of perfluoroalkyl substances partitioning between surface water, suspended sediment, and biota in a macrotidal estuary

A one-year monitoring study was conducted in a macrotidal estuary to assess the temporal variations and partitioning behavior of perfluoroalkyl and polyfluoroalkyl substances (PFASs). Surface water, suspended particulate matter (SPM), and invertebrates including zooplankton (copepods, mysids) and shrimps were sampled on a monthly basis in the Gironde Estuary (SW France). Environmental parameters such as suspended solid loads, salinity, and river water flow rate were highly variable at the study site. However, moderate seasonal variations were observed in terms of PFAS levels and profiles. Summed PFAS (Σ₂₂PFASs) concentrations averaged 6.5 ± 2.7 ng L^-1 in the dissolved phase and 3.0 ± 1.2 ng g^-1 dry weight in the SPM. The Σ₂₂PFASs was in the range of 1.7-13 ng g^-1 wet weight in invertebrates. C₅-C₈ perfluoroalkyl carboxylates (PFCAs) generally prevailed in the dissolved phase, while perfluorooctane sulfonate (PFOS) was dominant in the SPM and biota. Suspended sediment-water partitioning coefficients Log K_D and Log K_OC were correlated with the perfluoroalkyl chain length, as were the particle-bound fraction and bioaccumulation factors (Log BAF). Compound-specific Log BAFs varied within a limited range over the period surveyed. Biomagnification factors (mysids/copepods) were consistently >1 for PFOS, perfluorooctane sulfonamide, and long-chain PFCAs (perfluorodecanoate and perfluorododecanoate), suggesting biomagnification at the base of the estuarine food web.

Preliminary assessment of general population exposure to perfluoroalkyl substances through diet in Greece

Food and drinking water intake are the major routes of exposure to perfluoroalkyl substances (PFASs) for humans. In this study an initial oral exposure assessment of the non-occupationally exposed general Greek population to PFASs is presented. Levels of PFOA and PFOS determined in the present study in 128 food items from the Greek market and previously published analytical results of 43 water samples and 76 egg samples from Greece were combined with food availability data of the DAFNE-ANEMOS database for the calculation of oral intake of PFASs. Fish form the food group with the highest concentration in both PFOA and PFOS. For the general Greek population the estimated average daily intake in PFOA and PFOS when applying the lowerbound mean concentrations in food and drinking water samples is 0.49 and 0.91 ng kg^-1 body weight (b.w.) respectively. The main contributor to oral PFAS intake is fish. A pharmacokinetic model is applied to estimate total intake from blood serum levels reported previously and the predicted values are in agreement with lowerbound estimated values. Weekly intake estimated values are below the tolerable weekly intake recently proposed by EFSA.

Perfluoroalkyl substances in the riverine and coastal water of the Beibu Gulf, South China: Spatiotemporal distribution and source identification

Few studies have examined the perfluoroalkyl substances (PFASs) contamination in less-developed coastal regions. In the present study, we collected 19 riverine and 21 coastal surface water samples in the summer and winter of 2017 to investigate PFASs contamination in the Beibu Gulf, South China. The results show that eleven and twelve target PFASs were detected in the summer and winter, respectively. The total PFASs (ΣPFASs) concentrations in the water of the Beibu Gulf were in the range of 1609-4727 pg/L and 610-4920 pg/L in summer and winter, respectively. Perfluoropentanoic acid (PFPeA), perfluorobutanoic acid (PFBA) and perfluorobutane sulfonate (PFBS) were the predominantly detected PFASs in both seasons with maximum concentrations of 2968 pg/L, 1771 pg/L, and 1764 pg/L, respectively. Strong positive correlations between some PFASs were observed (e.g., PFBA and PFBS, PFOS and PFBS, p < 0.05), suggesting these correlated pollutants may share similar sources. PFASs contamination in the Beibu Gulf was strongly affected by ocean currents, and their concentrations were lower than most coastal waters around the world. Risk assessment indicates a low risk associated with target PFASs to aquatic organisms in the Beibu Gulf. The results of the present research provided a baseline and good overview of the spatial distribution of PFASs along the Beibu Gulf.

Risk to human health related to the presence of perfluorooctane sulfonic acid and perfluorooctanoic acid in food

The European Commission asked EFSA for a scientific evaluation on the risks to human health related to the presence of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in food. Regarding PFOS and PFOA occurrence, the final data set available for dietary exposure assessment contained a total of 20,019 analytical results (PFOS n = 10,191 and PFOA n = 9,828). There were large differences between upper and lower bound exposure due to analytical methods with insufficient sensitivity. The CONTAM Panel considered the lower bound estimates to be closer to true exposure levels. Important contributors to the lower bound mean chronic exposure were 'Fish and other seafood', 'Meat and meat products' and 'Eggs and egg products', for PFOS, and 'Milk and dairy products', 'Drinking water' and 'Fish and other seafood' for PFOA. PFOS and PFOA are readily absorbed in the gastrointestinal tract, excreted in urine and faeces, and do not undergo metabolism. Estimated human half-lives for PFOS and PFOA are about 5 years and 2-4 years, respectively. The derivation of a health-based guidance value was based on human epidemiological studies. For PFOS, the increase in serum total cholesterol in adults, and the decrease in antibody response at vaccination in children were identified as the critical effects. For PFOA, the increase in serum total cholesterol was the critical effect. Also reduced birth weight (for both compounds) and increased prevalence of high serum levels of the liver enzyme alanine aminotransferase (ALT) (for PFOA) were considered. After benchmark modelling of serum levels of PFOS and PFOA, and estimating the corresponding daily intakes, the CONTAM Panel established a tolerable weekly intake (TWI) of 13 ng/kg body weight (bw) per week for PFOS and 6 ng/kg bw per week for PFOA. For both compounds, exposure of a considerable proportion of the population exceeds the proposed TWIs.

Occurrence of Per- and Polyfluoroalkyl substances in Calonectris shearwaters breeding along the Mediterranean and Atlantic colonies

The objective of the present study was to assess the presence of 17 per- and polyfluoroalkyl substances (PFAS) in blood of two closely related top predators, the Scopoli's (Calonectris diomedea) and Cory's (C. borealis) shearwaters that breed allopatrically in Mediterranean and Atlantic basins. Among PFAS, perfluorooctanesulfononic acid (PFOS) and long chain perfluorinated carboxylic acids (PFCA) were detected in all samples, highlighting somehow the ubiquity of such pollutants. Scopoli's shearwaters from the Mediterranean showed significant higher levels in all PFAS when compared with those levels determined in the colony of Cory's shearwater from the Atlantic Ocean. Moreover, significant differences also arose within the Mediterranean colonies, with the colony of the Central Mediterranean (Zembra Island in Tunisia) having the lowest levels of all PFAS. Thus, our study suggests a marked geographical pattern regarding the presence of such contaminants, and emphasizes the necessity to study PFAS accumulation in birds inhabiting temperate regions.

Feasibility of using the National Marine Mammal Tissue Bank for retrospective exploratory studies of perfluorinated alkyl acids

Perfluorinated alkyl acids (PFAAs) have been used for 50+ years in materials such as stain-resistant treatments for paper and clothing, lubricants, and foam fire extinguishers. PFAAs are characterized by a fully fluorinated alkyl chain with a terminal acid group. Their long half-lives and ubiquitous environmental distribution create considerable concern for wildlife and human exposure. There is interest in examining temporal trends of PFAAs using the National Marine Mammal Tissue Bank (NMMTB), but NMMTB tissues are frozen and cryohomogenized in polytetrafluoroethylene (PTFE)-based materials. Because PTFE supplies may leach PFAAs into samples, this study mimicked collection, processing and storage steps of NMMTB samples and measured PFAA leaching to determine the feasibility of using this sample archive for PFAA temporal trends. We also explored concentrations in Atlantic white-sided dolphin (Lagenorhynchus acutus, WSDs) and rough-toothed dolphin (Steno bredanensis, RTDs) blubber (n=3 and 0) and liver (n=48 and 12, respectively). The materials used in NMMTB protocols may add up to 0.968ng/g perfluorooctanoic acid (PFOA), 0.090ng/g perfluorononanoic acid (PNFA), and 0.221ng/g perfluorooctane sulfonate (PFOS) to each archived sample. Leaching of PFNA and PFOS from supplies compared to dolphin levels was negligible, but PFOA contributions were substantially higher than levels found in most dolphin liver samples. Therefore, monitoring PFOA temporal trends from the NMMTB would require careful consideration. RTDs had significantly higher levels of PFOS and PFNA than WSDs. Both species have similar life history, trophic status, and foraging behaviors in deep pelagic waters, so differences could be from latitudinal variation in contamination. RTDs stranded in Florida; WSDs stranded farther north mostly in Massachusetts. Juveniles had significantly higher levels of PFOS and PFNA than adults in both species, suggesting growth dilution as they approach maturity. PFOS significantly decreased after 2001 in both species as expected based on changes in production.

Perfluorooctane sulfonate adsorption on powder activated carbon: Effect of phosphate (P) competition, pH, and temperature

Powdered activated carbon (PAC), as an adsorbent, was applied to remove perfluorooctane sulfonate (PFOS) from aqueous solution. Laboratory batch experiments were performed to investigate the influences of phosphate (P) competition, temperature, and pH for PFOS adsorption onto PAC. The results showed that higher temperature favored PFOS adsorption in single and binary systems. The kinetic data fitted very well to the pseudo second-order kinetic model. Thermodynamically, the endothermic enthalpy of the PFOS adsorption in single and binary systems were 125.07 and 21.25 kJ mol^-1, respectively. The entropy of the PFOS adsorption in single and binary systems were 0.479 and 0.092 kJ mol^-1 K^-1, respectively. And the Gibbs constants were negative. These results indicated that the adsorption processes were spontaneous. The adsorption isotherms of PFOS agreed well with the Langmuir model. In the single system, PFOS adsorption decreased with increased pH value. The difference in the amount of PFOS adsorption between the single and binary systems increased at higher pH. Frustrated total internal reflection (FTIR) demonstrated that P competition increased the hydrophilicity of the PAC and the electrostatic repulsion between PFOS and PAC, then the PFOS adsorption amount decreased. It also demonstrated that, at higher temperature, increased PFOS adsorption was mainly due to the higher diffusion rate of PFOS molecules and greater number of active sites opened on the PAC surface.

Role of Snow Deposition of Perfluoroalkylated Substances at Coastal Livingston Island (Maritime Antarctica)

Perfluoroalkyl substances (PFAS) are ubiquitous in the environment, including remote polar regions. To evaluate the role of snow deposition as an input of PFAS to Maritime Antarctica, fresh snow deposition, surface snow, streams from melted snow, coastal seawater, and plankton samples were collected over a three-month period (December 2014-February 2015) at Livingston Island. Local sources of PFASs were significant for perfluoroalkyl sulfonates (PFSAs) and C7-14 perfluoroalkyl carboxylates (PFCAs) in snow but limited to the transited areas of the research station. The concentrations of 14 ionizable PFAS (∑PFAS) in freshly deposited snow (760-3600 pg L^-1) were 1 order of magnitude higher than those in background surface snow (82-430 pg L^-1). ∑PFAS ranged from 94 to 420 pg L^-1 in seawater and from 3.1 to 16 ng g_dw^-1 in plankton. Ratios of individual PFAS concentrations in freshly deposited snow relative to surface snow (C_SD/C_Snow), snowmelt (C_SD/C_SM), and seawater (C_SD/C_SW) were close to 1 (from 0.44 to 1.4) for all perfluorooctanesulfonate (PFOS) isomers, suggesting that snowfall does not contribute significantly to PFOS in seawater. Conversely, these ratios for PFCAs ranged from 1 to 33 and were positively correlated with the number of carbons in the PFCA alkylated chain. These trends suggest that snow deposition, scavenging sea-salt aerosol bound PFAS, plays a role as a significant input of PFCAs to the Maritime Antarctica.

Accumulation of Perfluoroalkylated Substances in Oceanic Plankton

The bioaccumulation of perfluoroalkylated substances (PFASs) in plankton has previously been evaluated only in freshwater and regional seas, but not for the large oligotrophic global oceans. Plankton samples from the tropical and subtropical Pacific, Atlantic and Indian Oceans were collected during the Malaspina 2010 circumnavigation expedition, and analyzed for 14 ionizable PFASs, including perfluorooctanoate (PFOA), perfluorooctanesulfonate (PFOS) and their respective linear and branched isomers. PFOA and PFOS concentrations in plankton ranged from 0.1 to 43 ng g_dw^-1 and from 0.5 to 6.7 ng g_dw^-1, respectively. The relative abundance of branched PFOA in the northern hemisphere was correlated with distance to North America, consistent with the historical production and coherent with previously reported patterns in seawater. The plankton samples showing the highest PFOS concentrations also presented the largest relative abundances of branched PFOS, suggesting a selective cycling/fractionation of branched PFOS in the surface ocean mediated by plankton. Bioaccumulation factors (BAFs) for plankton were calculated for six PFASs, including short chain PFASs. PFASs Log BAFs (wet weight) ranged from 2.6 ± 0.8 for perfluorohexanesulfonic acid (PFHxS), to 4.4 ± 0.6 for perfluoroheptanoic acid (PFHpA). The vertical transport of PFASs due to the settling of organic matter bound PFAS (biological pump) was estimated from an organic matter settling fluxes climatology and the PFAS concentrations in plankton. The global average sinking fluxes were 0.8 ± 1.3 ng m^-2d^-1 for PFOA, and 1.1 ± 2.1 ng m^-2d^-1 for PFOS. The residence times of PFAS in the surface ocean, assuming the biological pump as the unique sink, showed a wide range of variability, from few years to millennia, depending on the sampling site and individual compound. Further process-based studies are needed to constrain the oceanic sink of PFAS.

Perfluoroalkyl acids (PFAAs) in water and sediment from the coastal regions of Shandong peninsula, China

Perfluoroalkyl acids (PFAAs) have been observed in various environmental matrices globally in recent years. In this study, the levels, spatial distribution tendencies, and partitioning characteristics of the target 12 PFAAs were investigated in water and sediment from the coastal regions of Shandong peninsula in China, and two sediment core samples were also collected to study the vertical and historical variation of PFAAs. The ranges (means) of total PFAA concentrations were 23.69-148.48 ng/L (76.11 ng/L) in the water and 1.30-11.17 ng/g (5.93 ng/g) in the surface sediment, respectively. Among the target 12 PFAAs, perfluorooctanoic acid (PFOA) was the dominant component in water, followed by perfluorooctane sulfonate (PFOS) and perfluorohexanoic acid (PFHxA). PFOS, perfluoroundecanoic acid, and PFOA were the dominant components in sediment. For their spatial distribution, higher levels of PFAAs were found at the locations close to much developed cities. The PFAA concentrations showed an overall decreasing tendency with depth increase in the two sediment cores, which indicates that the extent of PFAAs pollution is aggravating trend in recent years. Results of the partition coefficient (K _d ) show that the compounds with longer carbon chains (C ≥ 7) generally had higher K _d values, which suggest that long-chain PFAAs are prone to be adsorbed by sediment. In addition, the Log K _d of PFHxA, PFOA, and PFOS were significantly and positively correlated to the salinity of the water. The results of risk assessment suggest appreciable risk of PFAAs to the local ecosystem.

Co-adsorption of perfluorooctane sulfonate and phosphate on boehmite: Influence of temperature, phosphate initial concentration and pH

The co-presence of perfluorooctane sulfonate (PFOS) and phosphate in wastewater of various industries has been detected. Removing PFOS and phosphate simultaneously before discharging sewage into natural water can decrease effectively the environmental risk caused by the combined pollution of PFOS and phosphate. In this study, laboratory batch experiments were conducted for investigating the co-adsorption of PFOS and phosphate on boehmite and the influences of temperature, phosphate initial concentration and pH on the co-adsorption. The adsorption thermodynamics and kinetics of PFOS and phosphate on boehmite were also investigated completely and systematically. The results showed that lower temperature favored the co-adsorptions of PFOS and phosphate. The adsorption of PFOS and phosphate on boehmite agreed well with the Langmuir isotherm and the adsorption parameters of thermodynamics are ΔH=-16.9 and -20.0kJmol^-1 (PFOS and phosphate), ΔS=-5.69 and -7.63Jmol^-1 K^-1 (PFOS and phosphate) and ΔG <0 (PFOS and phosphate). It demonstrated that the co-adsorption of PFOS and phosphate on boehmite is a spontaneously exothermic process. Moreover, the co-adsorption process can be described well by a pseudo-second-order kinetic model. With increasing phosphate initial concentration, more phosphate could be adsorbed on boehmite, while the adsorption of PFOS decreased at phosphate initial concentration of less than 30mgL^-1 and increased at that of larger than 30mgL^-1. In the co-adsorption process, the adsorption amount of PFOS decreased with pH increasing, but that of phosphate changed little.

Maternal transfer of perfluoroalkyl substances in hooded seals

The role of milk in the transfer of perfluoroalkyl substances (PFASs) to offspring is not well known in wildlife. Eight PFASs were quantified in plasma and milk in mother-pup pairs of hooded seals (Cystophora cristata) during the nursing period, and the role of milk in the transfer process was analyzed. Hooded seal was chosen because of its short lactation period (3-4 d), during which the pup feeds only on milk. Placental or lactation transfer would thus be the only source of PFAS in the pup. Of the 8 PFASs analyzed (Σ₈ PFAS), 7 were found in all samples; therefore, milk is a source to PFASs in pups. Perfluorooctane sulfonate was the dominant PFAS in all samples. Mean Σ₈ PFAS concentrations were 6.0 ng/g protein (36 ng/g wet wt) in maternal plasma, 0.77 ng/g protein (3.2 ng/g wet wt) in milk, and 12 ng/g protein (66 ng/g wet wt) in pup plasma. Measured concentrations in plasma were within ranges previously reported from other seal species, below known toxicity thresholds for experimental rodents. Individual PFASs differed in transfer efficiency from mother to pup, depending on carbon chain lengths, with the lowest relative transfer for the intermediate-chained PFASs (C₉ -C₁₀ ). The results show maternal transfer of PFASs via both milk and the placenta, of which placental transfer is the dominant pathway. Environ Toxicol Chem 2017;36:763-770. © 2016 SETAC.

Spatial and temporal trends in perfluoroalkyl substances (PFASs) in ringed seals (Pusa hispida) from Svalbard

This study investigates concentrations of perfluoroalkyl carboxylates (PFCAs), perfluoroalkyl sulfonates (PFSAs) and perfluoroalkane sulfonamides (FASA) in plasma from ringed seals sampled in the period 1990-2010 (n = 71) in Svalbard, Norway. Perfluorooctane sulfonate was dominant among the perfluoroalkyl substances. PFCAs were dominated by perfluoroundecanoate followed by perfluorononanoate. C4C8 PFCAs and perfluorooctane sulfonamide (FOSA) were detected in ≤42% of the samples. PFSA and PFCA concentrations were higher in seals sampled from Kongsfjorden, a fjord influenced by strong inflows of Atlantic Water compared to seals from fjords dominated by Arctic Water (e.g. Billefjorden). Sex, age and body condition of the seals did not influence PFAS concentrations. Due to the confounding effect of year and sampling area, temporal trends were assessed only in seals sampled from Kongsfjorden (5 years, n = 51). PFHxS and PFOS concentrations did not show significant linear trends during the whole study period, but a decrease was observed since 2004. Concentrations of all of the detected PFCAs (C9C13 PFCAs) increased until 2004 after which they have declined or stabilized.

Microbial transformation of 8:2 fluorotelomer acrylate and methacrylate in aerobic soils

Biotransformation of fluorotelomer (FT) compounds, such as 8:2 FT alcohol (FTOH) is now recognized to be a source of perfluorooctanoic acid (PFOA) as well as other perfluoroalkyl acids. In this study, microbially mediated hydrolysis of FT industrial intermediates 8:2 FT acrylate (8:2 FTAC) and 8:2 FT methacrylate (8:2 FTMAC) was evaluated in aerobic soils for up to 105d. At designated times, triplicate microcosms were sacrificed by sampling the headspace for volatile FTOHs followed by sequential extraction of soil for the parent monomers as well as transient and terminal degradation products. Both FTAC and FTMAC were hydrolyzed at the ester linkage as evidenced by 8:2 FTOH production. 8:2 FTAC and FTMAC degraded rapidly with half-lives ⩽5d and 15d, respectively. Maximum 8:2 FTOH levels were 6-13mol% within 3-6d. Consistent with the known biotransformation pathway of 8:2 FTOH, FT carboxylic acids and perfluoroalkyl carboxylic acids were subsequently generated including up to 10.3mol% of PFOA (105d). A total mass balance (parent plus metabolites) of 50-75mol% was observed on the last sampling day. 7:2 sFTOH, a direct precursor to PFOA, unexpectedly increased throughout the incubation period. The likely, but unconfirmed, concomitant production of acrylic acids was proposed as altering expected degradation patterns. Biotransformation of 8:2 FTAC, 8:2 FTMAC, and previously reported 8:2 FT-stearate for the same soils revealed the effect of the non-fluorinated terminus group linked to the FT chain on the electronic differences that affect microbially-mediated ester cleavage rates.

Perfluoroalkyl substances (PFASs) and other halogenated compounds in fish from the upper Labe River basin

This study summarizes results on levels of 25 perfluoroalkyl substances (PFASs), three hexabromocyclododecane isomers (HBCDs), tetrabromobisphenol A (TBBPA), three brominated phenols and four hydroxylated derivates of polybrominated diphenyl ethers (OH-PBDEs) in 59fish samples collected in nine localities on two major rivers from the Czech Republic. To identify potential sources of these chemicals, several sampling sites located close to highly industrialized areas were also involved. The major PFAS representatives, perfluorooctane sulfonate (PFOS), C9-C14 perfluoroalkyl carboxylic acids (PFCAs) and perfluorooctane sulfonamide (FOSA) were detected in 100% fish samples. The concentration ranges of individual substances in the respective groups of PFASs were as follows: 0.572-61.3ngg(-)(1) wet weight (ww) for Tot-PFOS, 0.007-0.121ngg(-)(1)ww for perfluoroalkane sulfonates (PFSAs) (without PFOS isomers), 0.007-22.0ngg(-)(1)ww for PFCAs and 0.026-7.76ngg(-)(1)ww for FOSA. The highest contents of ∑PFASs (51.9ngg(-)(1)ww and 47.8ngg(-)(1)ww) were measured in fish muscle tissue from the locality Trmice situated on the Bílina River and Verdek on the Labe River, where chemical and/or textile industry is located. From 11 targeted BFRs, five compounds (α-HBCD, β-HBCD, γ-HBCD, TBBPA and 2,4,6-tribromophenol (TBP)) were determined in analyzed samples. The concentration ranged as follows: 3.15-1211ngg(-)(1) lipid weight (lw) for ∑HBCD, 4.99-203ngg(-)(1)lw for TBBPA and 1.76-107ngg(-)(1)lw for 2,4,6-TBP.

Isomer-specific trophic transfer of perfluorocarboxylic acids in the marine food web of Liaodong Bay, North China

Trophic transfers of perfluorocarboxylic acids (PFCAs) have been well studied in aquatic food webs; however, most studies examined PFCAs as single compounds without differentiating isomers. In this study, an in-port derivatization GC-MS method was used to determine PFCA (perfluorooctanoic acid, PFOA; perfluorononanoic acid, PFNA; perfluorodecanoate acid, PFDA; perfluoroundecanoate acid, PFUnDA; perfluorododecanoate acid, PFDoDA; perfluorotridecanoate acid, PFTriDA, and perfluorotetradecanoate acid, PFTeDA) structural isomers in 11 marine species including benthic invertebrates, fishes, and gulls collected in November 2006 from Liaodong Bay in China. The total concentrations of linear PFCAs were 0.35-1.10, 0.93-2.61, and 2.13-2.69 ng/g ww, and the corresponding percentages of branched PFCAs to linear PFCAs were 6.6-15.5%, 4.2-9.9%, and 4.5-6.0% in invertebrates, fishes, and birds, respectively. Except for linear PFOA, significant positive relationships were found between the concentrations of all the target linear PFCAs and trophic levels, and the trophic magnification factors (TMFs) ranged from 1.90 to 4.88. Positive correlations between the concentrations of branched PFCAs isomers and trophic levels were also observed but were without statistical significance. The relatively high biomagnification of linear isomers of PFCAs would lead to low percentages of branched PFCAs to total PFCAs in organisms at high trophic levels. This study for the first time clarified isomer-specific trophic transfers of PFCAs in a marine food web.

Perfluoroalkyl substances detected in the world's southernmost marine mammal, the Weddell seal (Leptonychotes weddellii)

This study investigates concentrations of 18 perfluoroalkyl substances (PFAS) in blood plasma of adult lactating Weddell seals (Leptonychotes weddellii) (n = 10) from McMurdo Sound, Antarctica. Perfluoroundecanoic acid (PFUnDA) was detected in all samples at concentrations ranging from 0.08 to 0.23 ng/ml. Perfluorooctane sulfonate (PFOS), perfluorohexanoate (PFHxA) and perfluorotridecanoate (PFTriDA) were sporadically detected, while the remaining compounds were below the limit of detection. This is the first report of detectible concentrations of PFASs in an endemic Antarctic marine mammal species. We suggest that the pollutants have been subjected to long range atmospheric transportation and/or derive from a local source. A review of these and published data indicate that perfluoroalkyl carboxylates (PFCAs) dominate in biotic PFAS patterns in species feeding south of the Antarctic Circumpolar Current (ACC), whereas PFOS was the major PFAS detected in species feeding predominantly north of the current.

Effect of body condition on tissue distribution of perfluoroalkyl substances (PFASs) in Arctic fox (Vulpes lagopus)

Arctic animals undergo large seasonal fluctuations in body weight. The effect of body condition on the distribution and composition of 16 perfluoroalkyl substances (PFASs) was investigated in liver, blood, kidney, adipose tissue, and muscle of Arctic foxes (Vulpes lagopus) from Svalbard (n = 18, age 1-3 years). PFAS concentrations were generally highest in liver, followed by blood and kidney, while lowest concentrations were found in adipose tissue and muscle. Concentrations of summed perfluorocarboxylic acids and perfluoroalkyl sulfonates were five and seven times higher, respectively, in adipose tissue of lean compared to fat foxes. In addition, perfluorodecanoate (PFDA) and perfluoroheptanesulfonate (PFHpS) concentrations in liver, kidney, and blood, and, perfluorononanoate (PFNA) in liver and blood, were twice as high in the lean compared to the fat foxes. The ratio between perfluorooctane sulfonamide (FOSA) and its metabolite perfluorooctanesulfonate (PFOS) was lowest in liver, muscle, and kidney, while significantly higher proportions of FOSA were found in adipose tissue and blood. The results of the present study suggest that toxic potential of exposure to PFAS among other pollutants in Arctic mammals may increase during seasonal emaciation. The results also suggest that body condition should be taken into account when assessing temporal trends of PFASs.

Distribution of perfluoroalkyl substances (PFASs) with isomer analysis among the tissues of aquatic organisms in Taihu Lake, China

The distribution of perfluoroalkyl substances (PFASs) and the isomers of perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) was investigated among various tissues (including muscle, gill, kidney, liver) and eggs, in aquatic organisms in Taihu Lake, China. Highest concentration of ΣPFASs was mostly found in liver (278-685 ng/g ww) and eggs (66.0-467 ng/g ww) while the lowest was in muscle (40.6-165 ng/g ww). n-PFOS was the predominant PFOS isomer in most of the tissues with a proportion of 46.3-96.5%. Ratios of PFAS concentrations in eggs to those in liver (E/L) increased positively with the protein-water partition coefficient. The E/L of PFOS isomers descended in the order: linear > monomethyl > diperfluoromethyl isomers. The liver/muscle and kidney/muscle ratios of n-PFOS were higher than branched isomers, suggesting that n-PFOS has higher binding affinity with hepatic proteins or branched isomers are preferentially excreted though liver and kidney.