Long-chain Perfluoroalkyl Acids Research Articles

Can on-site leachate treatment facilities effectively address the issue of perfluoroalkyl acids (PFAAs) in leachate?

In recent decades, the presence of perfluoroalkyl acids (PFAAs) in municipal solid waste leachate has emerged as a growing concern. Research has focused on PFAA release and occurrence characteristics in landfill and waste-to-energy leachate, highlighting their significant impact when released into wastewater treatment plants. Given the extremely high loading rate faced by current on-site leachate treatment plants (LTPs), the objective of this study is to assess whether the current “anaerobic/aerobic (A/O) + membrane bioreactor (MBR) + nanofiltration (NF) + reverse osmosis (RO)” configuration is effective in PFAAs removal. Concentrations of raw and treated leachate in 10 on-site LTPs with same treatment configuration and varying landfill ages were measured, and a comprehensive mass flow analysis of each treatment process was conducted. The results indicate that A/O treatment has limited capacity for PFAA removal, while NF and RO processes reached 77.44 % and 94.30 % removal rates of ∑PFAAs concentration, respectively. Short-chain PFAAs (> 80 % detected frequency) primarily influenced the distribution and variations of PFAAs in leachate and tend to disperse in the water phase. Correlation analysis revealed the current on-site LTPs exhibit a more efficient removal capacity for long-chain PFAAs.

Removal of perfluoroalkyl acids (PFAAs) from aqueous solution by water hyacinth (Eichhornia crassipes): Uptake, accumulation, and translocation

Although Eichhornia crassipes, commonly known as water hyacinth, has been widely used in wastewater treatment, further investigations are still needed to explore the removal efficiency of perfluoroalkyl acids (PFAAs) from the aqueous environment using this floating aquatic plant. In this study, a hydroponic experiment was conducted to assess accumulation, bioconcentration factors (BCFs), translocation factors (TFs), and removal rates of eight PFAAs by water hyacinth. The obtained results indicated that all PFAAs, including five perfluoroalkyl carboxylic acids (PFCAs) with chain lengths C4-C8 and three perfluoroalkyl sulfonic acids (PFSAs) with C4, C6, and C8, were readily accumulated in water hyacinth. Throughout the duration of the experiment, there was a noticeable increase in PFAA concentrations and BCF values for different plant parts. For the root, PFAAs with more carbon numbers showed a higher uptake than the shorter homologues, with PFSAs being more readily accumulated compared to PFCAs with the same carbon number in the molecules. In contrast, the levels of long-chain PFAAs were comparatively lower than those of short-chain substances in the stem and leaf. Notably, PFAAs with less carbon numbers, like PFPeA, PFBA, and PFBS, showed a remarkable translocation from the root to the stem and leaf with TFs >1. For the whole plant, no significant correlation was found between BCFs and organic carbon-water partition coefficients (Koc), octanol-water partition coefficients (Kow), membrane-water distribution coefficients (Dmw), or protein-water distribution coefficients (Dpw). The removal rates of PFAAs ranged from 40.3 to 63.5 % throughout the three weeks of the experiment while the removal efficiencies varied from 48.9 % for PFHxS to 82.6 % for PFPeA in the last week.

Species-specific profiles of per- and polyfluoroalkyl substances (PFAS) in small coastal sharks along the South Atlantic Bight of the United States

Per- and polyfluoroalkyl substances (PFAS) have gained widespread commercial use across the globe in various industrial and consumer products, such as textiles, firefighting foams, and surface coating materials. Studies have shown that PFAS exhibit a strong tendency to accumulate within aquatic food webs, primarily due to their high bioaccumulation potential and resistance to degradation. Despite such concerns, their impact on marine predators like sharks remains underexplored. This study aimed to investigate the presence of 34 PFAS in the plasma (n = 315) of four small coastal sharks inhabiting the South Atlantic Bight of the United States (U.S). Among the sharks studied, bonnetheads (Sphyrna tiburo) had the highest ∑PFAS concentration (3031 ± 1674 pg g − 1 plasma, n = 103), followed by the Atlantic sharpnose shark (Rhizoprionodon terraenovae, 2407 ± 969 pg g − 1, n = 101), blacknose shark (Carcharhinus acronotus, 1713 ± 662 pg g − 1, n = 83) and finetooth shark (Carcharhinus isodon, 1431 ± 891 pg g − 1, n = 28). Despite declines in the manufacturing of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), the long-chain (C8 – C13) perfluoroalkyl acids (PFAAs) were frequently detected, with PFOS, perfluorodecanoic acid (PFDA), and perfluorotridecanoic acid (PFTrDA) present as the most dominant PFAS. Furthermore, males exhibited significantly higher ∑PFAS concentrations than females in bonnetheads (p < 0.01), suggesting possible sex-specific PFAS accumulation or maternal offloading in some species. The results of this study underscore the urgency for more extensive biomonitoring of PFAS in aquatic/marine environments to obtain a comprehensive understanding of the impact and fate of these emerging pollutants on marine fauna.

Per- and Polyfluoroalkyl Substances in Food Packaging: Migration, Toxicity, and Management Strategies.

PFASs are linked to serious health and environmental concerns. Among their widespread applications, PFASs are known to be used in food packaging and directly contribute to human exposure. However, information about PFASs in food packaging is scattered. Therefore, we systematically map the evidence on PFASs detected in migrates and extracts of food contact materials and provide an overview of available hazard and biomonitoring data. Based on the FCCmigex database, 68 PFASs have been identified in various food contact materials, including paper, plastic, and coated metal, by targeted and untargeted analyses. 87% of these PFASs belong to the perfluorocarboxylic acids and fluorotelomer-based compounds. Trends in chain length demonstrate that long-chain perfluoroalkyl acids continue to be found, despite years of global efforts to reduce the use of these substances. We utilized ToxPi to illustrate that hazard data are available for only 57% of the PFASs that have been detected in food packaging. For those PFASs for which toxicity testing has been performed, many adverse outcomes have been reported. The data and knowledge gaps presented here support international proposals to restrict PFASs as a group, including their use in food contact materials, to protect human and environmental health.

Cardiometabolic health and per and polyfluoroalkyl substances in an Inuit population

IntroductionThe cardiometabolic health status of Inuit in Nunavik has worsened in the last thirty years. The high concentrations of perfluoroalkyl acids (PFAAs) may be contributing to this since PFAAs have been linked with hypercholesterolemia, diabetes, and high blood pressure. The aim of this study was to examine the association between a PFAAs mixture and lipid profiles, Type II diabetes, prediabetes, and high blood pressure in this Inuit population. MethodsWe included 1212 participants of the Qanuilirpitaa? 2017 survey aged 16–80 years. Two mixture models (quantile g-computation and Bayesian Kernel Machine Regression (BKMR)) were used to investigate the associations between six PFAAs (PFHxS, PFOS, PFOA and three long-chain PFAAs (PFNA, PFDA and PFUnDA)) with five lipid profiles and three cardiometabolic outcomes. Non-linearity and interaction between PFAAs were further assessed. ResultsAn IQR increase in all PFAAs congeners resulted in an increase in total cholesterol (β 0.15, 95% confidence interval (CI) 0.06, 0.24), low-density lipoprotein cholesterol (LDL) (β 0.08, 95% CI 0.01, 0.16), high-density lipoprotein cholesterol (HDL) (β 0.04, 95% CI 0.002, 0.08), apolipoprotein B-100 (β 0.03, 95% CI 0.004, 0.05), and prediabetes (OR 1.80, 95% CI 1.11, 2.91). There was no association between PFAAs and triglycerides, diabetes, or high blood pressure. Long-chain PFAAs congeners were the main contributors driving the associations. Associations were largely linear, and there was no evidence of interaction between the PFAAs congeners. ConclusionsOur study provides further evidence of increasing circulating lipids with increased exposure to PFAAs. The increased risk of prediabetes points to the influence of PFAAs on potential clinical outcomes. International regulation of PFAAs is essential to curb PFAAs exposure and related health effects in Arctic communities.

Revealing the factors resulting in incomplete recovery of perfluoroalkyl acids (PFAAs) when implementing the adsorbable and extractable organic fluorine methods

Per- and polyfluoroalkyl substances (PFASs) are environmental contaminants of concern. Techniques that quantify total organic fluorine (TOF) such as the adsorbable organic fluorine (AOF) and extractable organic fluorine (EOF) methods are important for PFAS risk assessments. The objective of this study was to systematically evaluate each step of the AOF (loading, washing, combustion) and EOF (loading, washing, elution, combustion) methods for the recovery of ten ultrashort-, short-, and long-chain unsubstituted perfluoroalkyl acids (PFAAs). We measured the overall recovery of fluoride for each method for each PFAA, and the recovery of each PFAA around the loading, washing, and elution steps. We also measured the combustion efficiency of each PFAA by direct combustion. The overall AOF and EOF recovery ranged from 9.3%–103.3% to 21.0%–108.1%, respectively, with higher recoveries measured for PFAAs with increasing chain length in both methods. The three ultrashort-chain PFAAs (trifluoroacetic acid, perfluoropropionic acid, and perfluoropropanesulfonic acid) exhibited the lowest overall recoveries from 9.3–25.2% for AOF and 21.0–51.5% for EOF. We found that decreases in the overall recovery are the result of losses of ultrashort- and short-chain PFAAs during the washing step and the incomplete mineralization of perfluoroalkyl sulfonic acids during combustion for AOF and incomplete elution of short- and long-chain PFAAs and the loss of ultrashort-chain PFAAs during the washing step for EOF. Our data suggest that the EOF method is more appropriate than the AOF method for measuring TOF in samples containing ultrashort- and short-chain PFAAs and that methodological improvements are possible with a focus on the washing, elution, and combustion steps.

PFAS-CTAB Complexation and Its Role on the Removal of PFAS from a Lab-Prepared Water and a Reverse Osmosis Reject Water Using a Plasma Reactor.

Electrical discharge plasma reactors with argon bubbling can effectively treat long-chain perfluoroalkyl acids (PFAAs) in contaminated water, and the addition of a cationic surfactant cetrimonium bromide (CTAB) is known to enhance the removal of short-chain PFAAs. However, the roles of PFAA chain length, functional group, and water matrix properties on PFAA-CTAB complexation are largely unknown. This work investigated the bulk liquid removal of different PFAAs by CTAB in the absence of plasma. Stepwise addition of CTAB was subsequently used to efficiently treat PFAAs in a lab-prepared water and a reverse osmosis (RO) reject water using an enhanced contact plasma reactor. The results show that CTAB inhibited the bulk liquid removal of long-chain PFAAs in the absence of plasma likely due to the formation of hydrophilic CTAB-PFAA mixed micelles and competition for interfacial access between long-chain PFAAs and CTAB. On the contrary, CTAB enhanced the removal of short- and ultrashort-chain PFAAs by forming hydrophobic complexes. After 6 h of treatment in the plasma reactor with CTAB, PFAAs were 86 to >99% removed from the lab-prepared water and 29 to >99% removed from the RO reject water. This study provides important insights for overcoming mass transfer limitations for PFAA treatment technologies.

Concentration, distribution, and bioconcentration of short- and long-chain perfluoroalkyl substances in the water, suspended particulate matter, and surface sediment of a typical semi-enclosed bay

This study investigated per- and polyfluoroalkyl substances (PFAS) levels in the surface water, suspended particulate matter (SPM), sediment, and fishes in the Laizhou Bay (LZB) and its inflow river estuaries in dry, normal, and wet seasons. The results demonstrated that the short-chain perfluoroalkyl acids (PFAA) accounted for about 60 % of the total PFAA (∑PFAA) concentration in water, while long-chain PFAA were the dominant compounds in the sediment and SPM. The levels of the ∑PFAA and their precursors decreased from the estuaries to the bay, which implied that terrigenous input (pollutant in land flowed into sea) was the main pollution source of PFAA in the LZB. The PFAAs levels in surface water were ranked as the order of dry > normal > wet season. The distribution coefficients of PFAA showed that the long-chain PFAA were more prone to be adsorbed by sediment and SPM than short-chain PFAA. The increase of ∑PFAA concentrations was in the range of 0.32–36.7 ng·L−1 after the oxidation conversion of water samples. Precursors were the important source of the PFAA in the surface water. The perfluorooctane sulfonate (PFOS) was the dominant compound in fish tissues. These results provide hints for understanding PFAS pollution in LZB.

Mechanisms of propeller jet-induced migration, release, and distribution of perfluoroalkyl acids in sediment–water systems

Perfluoroalkyl acids (PFAAs) are continuously accumulated in surface sediments due to extensive and long-term application. However, the mechanisms through which disturbances induced by ship propeller jets at the riverbed cause secondary release of PFAAs from sediments remain unclear. In this study, the effects of different propeller rotational speeds on PFAA migration, release, and distribution in multiphase media were investigated by performing indoor flume experiments combined with particle tracking velocimetry. Moreover, key factors influencing PFAA migration and distribution were identified, and partial least squares regression (PLS) method was applied to develop quantitative prediction models of relationships among hydrodynamics, physicochemical parameters, and PFAA distribution coefficients. The total PFAA concentrations (ΣPFAAs) in overlying water under propeller jet action exhibited transient characteristics and hysteresis with time after the disturbance. In contrast, the ΣPFAAs in suspended particulate matter (SPM) exhibited an upward trend throughout the process with consistent characteristics. The spatial distribution trends of PFAAs in overlying water and SPM at different propeller rotational speeds featured vertical variability and axial consistency. Furthermore, PFAA release from sediments was driven by axial flow velocity (Vx) and Reynolds normal stress Ryy, while PFAA release from porewater was inextricably linked to Reynolds stresses Rxx, Rxy, and Rzz (p < 0.05). PLS regression models showed that variations in Vorticity, dissolved organic carbon, and pH influenced the decreases in PFAA distribution coefficients between SPM and overlying water (KD-SW) as propeller rotational speed increased, except for very long-chain PFAAs (C > 10). The increases in PFAA distribution coefficients between sediment and porewater (KD-SP) were mainly determined by physicochemical parameters of sediments, and the direct effect of hydrodynamics was relatively weak. Our study provides valuable information regarding the migration and distribution of PFAAs in multiphase media under propeller jet disturbance (both during and after disturbance).

The influence of environmental and ecological factors on the accumulation and distribution of short- and long-chain perfluoroalkyl acids in a mid-trophic avian insectivore

Perfluoroalkyl acids (PFAAs) include perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), and perfluorodecane sulfonic acid (PFDS), as well as increasingly used alternative short-chain perfluorosulfonic acids (PFSAs) and short- and long-chain (≥C9) perfluorocarboxylic acids (PFCAs). In the present study, tissues of tree swallows (Tachycineta bicolor) from two sites in southern Ontario, Canada, were analyzed for 17 individual PFAAs and showed egg and nestling tissue (liver, carcass) profiles dominated by PFOS (57–66%). The remaining PFAAs contributed ≤7% each, although collectively the long-chain PFCAs comprised 21–29% of the PFAAs. The short-chain PFSAs and PFCAs were among the lowest concentrations, suggesting that despite increased production and use of these alternative PFAAs, they are not accumulated to the same extent as the long-chain PFSAs and PFCAs. PFOS, PFDS, and some long-chain PFCAs were significantly higher in eggs than in livers and carcasses, whereas PFOA and the two short-chain PFCAs were significantly higher in nestling tissues than in eggs. For the two short-chain PFSAs, concentrations were similar among tissues. Tree swallow tissues at the site near a wastewater treatment plant (WWTP) outfall showed higher concentrations of PFOS, PFDS, PFHxS, and some long-chain PFCAs than tree swallows sampled at the nearby reference site; however, the influence of the WWTP was more equivocal for PFOA, other long-chain PFCAs, and short-chain PFSAs and PFCAs. Carbon stable isotopes (δ13C) and fatty acid signatures indicated that the diets of the WWTP swallows were more terrestrial than the reference swallows. Nonetheless, models considering environmental and ecological variables indicated that site was often the primary driver of PFAA variation among the swallows, with less or no influence of dietary patterns, or sex or body condition, revealing that of WWTP effluent can be an important environmental source of the major PFAAs in tree swallows.

Does contaminant exposure disrupt maternal hormones deposition? A study on per- and polyfluoroalkyl substances in an Arctic seabird

Maternal effects are thought to be essential tools for females to modulate offspring development. The selective deposition of avian maternal hormones could therefore allow females to strategically adjust the phenotype of their offspring to the environmental situation encountered. However, at the time of egg formation, several contaminants are also transferred to the egg, including per- and polyfluoroalkyl substances (PFAS) which are ubiquitous organic contaminants with endocrine disrupting properties. It is, however, unknown if they can disrupt maternal hormone deposition. In this study we explored relationships between female PFAS burden and maternal deposition in the eggs of steroids (dihydrotestosterone, androstenedione and testosterone), glucocorticoids (corticosterone) and thyroid hormones (triiodothyronine and thyroxine) in a population of the Arctic-breeding black-legged kittiwake (Rissa tridactyla). Egg yolk hormone levels were unrelated to female hormone plasma levels. Second-laid eggs had significantly lower concentrations of androstenedione than first-laid eggs. Triiodothyronine yolk levels were decreasing with increasing egg mass but increasing with increasing females' body condition. Testosterone was the only transferred yolk hormone correlated to maternal PFAS burden: specifically, we found a positive correlation between testosterone in yolks and circulating maternal perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDcA) and perfluoroundecanoic acid (PFUnA) in first-laid eggs. This correlative study provides a first insight into the potential of some long-chain perfluoroalkyl acids to disrupt maternal hormones deposition in eggs and raises the question about the consequences of increased testosterone deposition on the developing embryo.

Perfluoroalkyl acids in the aquatic environment of a fluorine industry-impacted region: Spatiotemporal distribution, partition behavior, source, and risk assessment.

The present study investigated the temporal and spatial distributions, partition behaviors, sources, and risks of 14 perfluoroalkyl acids (PFAAs) in the aquatic environment of a fluorine industry-impacted region. The total concentrations of 14 PFAAs (ΣPFAAs) were 118.10-2235.4 ng/L, 40.00-2316.1 ng/g dw, and 6.90-180.5 ng/g dw in dissolved, suspended particle matter (SPM), and sedimentary phases, respectively. The predominant pollutants in the dissolved and SPM phases were perfluoroalkyl carboxylic acids (PFCAs) with carbon chain lengths <9, whereas C13 and C14 PFCAs accounted for a large proportion in the sedimentary phase. The dry season exhibited the highest concentration of ΣPFAAs in the dissolved phase (500.9 ± 350.2 ng/L), while the wet season showed the highest concentrations of ΣPFAAs in the SPM and sedimentary phases (591.6 ± 469.1 ng/g dw and 59.7 ± 35.5 ng/g dw, respectively). Significantly higher concentrations of PFAAs have been found in sewage plant and industrial areas. The concentration of PFAAs in the Xupu water source area (XPS) was slightly higher than that in other water source areas of the Yangtze River, which were either not affected or were less affected by the fluorine industry. The log KD-SPM (distribution coefficient between SPM and water), log KD-SED (distribution coefficient between sediment and water), and log KOC-SED (the organic carbon normalized distribution coefficient) of PFAAs showed significant differences between the wet season and dry season, which may also be affected by carbon chain length. Source identification results showed that industries, wastewater discharge, and nonpoint sources were the main sources of PFAAs in this region. The ecological risk posed by long-chain PFAAs in aquatic organisms cannot be ignored, especially in areas with intensive industrial and agricultural activities. Health risks may exist for local toddlers with long-term exposure to perfluorooctanoic acid (PFOA) through drinking water intake and dermal contact.

Occurrence, partitioning and transport of perfluoroalkyl acids in gas and particles from the southeast coastal and mountainous areas of China.

Perfluoroalkyl acids (PFAA) in gas and particles were analyzed in southeast coastal and mountainous cities, including Fuzhou, Xiamen, Zhangzhou and Nanping, to study the pollution characteristics, particle size distribution, phase partitioning and atmospheric transport. PFAA ranged from 7.8 to 290pgm-3 in gaseous phase, 27 - 1200pgm-3 in particulate phase, and perfluorobutanoic acid (PFBA), perfluorooctanoic acid (PFOA) were main compounds. PFAA had the highest concentration in Nanping with perfluorohexanoic acid (PFHxA) dominant, which could be related to the emission of PFAS from local industrial plants. Perfluorocarboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) exhibited different particle size distribution characteristics, with PFSAs preferring to distribute on coarse particles, which could be affected by the salt, minerals and organic matter in different particle sizes. The gas - particle partitioning coefficient (KPA) had a line relationship with the fluorinated carbon chain length of PFAA, suggesting that long-chain PFAA tended to exist in particulate phase. The Winter Monsoon could transport to the study area and drive atmospheric PFAS to southern cities. HIGHLIGHTS: • Industrial plants contributed high concentrations of PFAA. • PFSAs tended to present in coarse particles. • Log KPA increased linearly with increasing carbon chain length of PFAA. • Winter Monsoon drove atmospheric PFAA to southern cities.

Perfluoroalkyl acids (PFAAs) in water along the entire coastal line of China: Spatial distribution, mass loadings, and worldwide comparisons.

Perfluoroalkyl acids (PFAAs) have been ubiquitously distributed in water environment worldwide for a long time, especially in the estuaries and coastal areas. In this study, the distribution characteristics of 12 PFAAs in 91 main river estuaries along the entire coast of China were analyzed for the first time, and the riverine PFAAs fluxes into the coastal marine environment were estimated. Based on a mini-review, the PFAAs pollution in the coast of China at a global scale was evaluated, which was intended to reveal the overall level of PFAAs and to provide a science basis for strengthening environmental management along the coast of China. The results showed that perfluorooctanoic acid (PFOA), perfluorobutanoic acid (PFBA), and perfluorobutane sulfonic acid (PFBS) were dominant in the whole coastal region, which indicated the usage of PFAAs was changing from long-chain PFAAs to short-chain substitutes in China. With regard to the spatial distribution, the high PFAAs concentrations were found in the coastal areas of south Bohai Sea, Shandong Province from the north while those in the south were generally lower when taking the Qinling Mountain and Huaihe River as a dividing line. The estimated PFAAs riverine mass loading in the whole coastal region was 131 tons per year, and the discharge flux of the Yangtze River accounted for more than half (73.5 tons). In comparison with global data, PFAAs concentrations in the coast of China was at a moderate level, and the detected hotspots of high levels were strongly influenced by fluorochemical industries. However, the mass loading of PFAAs was diversified due to geographical differences and abundant river discharges.

Plasma concentrations of perfluoroalkyl acids and their determinants in youth and adults from Nunavik, Canada

Perfluoroalkyl acids (PFAAs), a subset of per- and poly-fluoroalkyl substances (PFAS), are environmentally stable, mobile and bioaccumulative compounds. This leads to high concentrations in wildlife species essential to the cultural identity and subsistence of Arctic populations. Our objective was to characterize the distribution and exposure determinants of PFAAs among Nunavik Inuit adults. The study included up to 1322 Nunavik residents aged 16–80 years who participated in the Qanuilirpitaa? 2017 Nunavik Inuit Health Survey (Q2017). Plasma concentrations were compared to those the general Canadian population using data from the Canadian Health Measures Survey Cycle 5 (2016–2017). Associations between plasma concentrations of nine PFAAs, determined by liquid chromatography-tandem mass spectrometry, and sociodemographic factors and traditional activity participation were examined using multiple linear regression models. Overall exposure to PFAAs was twice as high compared to the general Canadian population and less regulated perfluorononanoic acid (PFNA) and perfluoroundecanoic acid (PFUnDA) concentrations were 7-fold higher, and perfluorodecanoic acid (PFDA) concentrations were 4-fold higher. Males had higher concentrations of perfluorooctanoic acid (PFOA) and perfluorohexane sulfonate (PFHxS), whereas females had higher concentrations of PFDA and PFUnDA. PFAAs concentrations increased with age and were highest among those aged 60+ years. PFNA and PFOA concentrations followed a J-shaped pattern: those aged 16–29 years had higher concentrations than those aged 20–29 and 30–39 years. Ungava Bay generally had lower concentrations of all PFAAs congeners compared to Hudson Bay and Hudson Strait, with the exception of PFNA, which tended to have the lowest concentration in Hudson Strait. PFAAs concentrations were highly associated with hunting activity, omega-3 polyunsaturated fatty acids, and drinking water from environmental sources. The results highlight the importance of characterizing PFAAs exposure sources in Arctic communities and provide further evidence for the long-range transport of long-chain PFAAs and their precursors that necessitate international action.

Transdermal absorption of 13C4-perfluorooctanoic acid (13C4-PFOA) from a sunscreen in a male volunteer – What could be the contribution of cosmetics to the internal exposure of perfluoroalkyl substances (PFAS)?

Per- and polyfluoroalkyl substances (PFAS) are a complex group of man-made chemicals with high stability and mobility leading to ubiquitous environmental contamination and accumulation especially of some long-chain perfluoroalkyl acids (PFAA) in humans. While dietary intake is the main route of exposure, transdermal uptake from cosmetic products usually is considered negligible. However, PFAS are present in a part of these products, and recent epidemiological studies have provided evidence for relevant uptake via this route. The crucial question is whether PFAA in cosmetic products can cross the human skin barrier. A defined amount (110 µg) of 13C4-perfluorooctanoic acid (13C4-PFOA) was mixed into a sunscreen (30 g) which was applied on the whole skin of a volunteer. The plasma concentrations of 13C4-PFOA were determined in serial blood samples taken over 115 days using UHPLC-MS/MS and 13C2-PFOA as internal standard. After application, 13C4-PFOA plasma levels increased continuously, reaching levels of 3, 56 and 118 ng/L after 6 h, 3 days and 10 days, respectively. A maximum level of 132 ng/L was measured 22 days after application, representing 9.4 % of the PFOA level resulting from the volunteer’s background exposure (1400 ng/L, equivalent to 1.4 ng/mL). In the following weeks, the levels slightly decreased with an estimated half-life of 1.8 years. The best estimate for the fraction absorbed may be 1.6 % of the dose, using a volume of distribution of 0.17 L/kg body weight. For PFOA mixed into a sunscreen, this experimental approach demonstrates a significant uptake of a PFAA via transdermal absorption in humans. In the past, some cosmetic products contained relevant PFAA levels as contaminants/impurities of PFAS added as active ingredients. Depending on these levels and the use (frequency, skin area involved), it is plausible that this route of exposure has contributed to the internal exposure to PFAA, as already suggested by epidemiological observations.

Contamination of country foods by perfluoroalkyl acids in the Arctic

BACKGROUND AND AIM: Perfluoroalkyl acids (PFAAs) are synthetic chemicals used in industrial and consumer applications. They are exceptionally stable and highly mobile in the environment, and have been detected in high concentrations in Nunavik Inuit adults. The study’s objectives were to study the associations between dietary profiles in Nunavik and PFAAs concentrations, and the associations between specific foods and PFAAs concentrations. METHODS: The study used data from the Qanuilirpitaa? 2017 Nunavik Inuit Health Survey. Nine PFAAs congeners were measured in plasma samples, including perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA) and perfluoroundecanoic acid (PFUdA). Dietary profiles were identified using latent profile analysis. Multiple linear regression models regressed log-transformed PFAAs concentrations against the dietary profiles, adjusting for sociodemographic variables. Elastic net was used to look at associations between PFAAs and dietary variables. RESULTS: We identified strong associations between the dietary profile defined by frequent country food consumption and all PFAAs congeners (PFOA, PFNA, PFDA, PFUdA, PFHxS, and PFOS) compared to the dietary profile defined by frequent market food consumption. Individuals with low consumption of all foods also had higher concentrations of all PFAAs congeners compared to individuals with frequent market food consumption. The associations were stronger with profiles defined by more frequent country food consumption, and particularly those with increased marine mammal consumption. Elastic net identified marine mammal products (seal liver, beluga misirak), wild birds (ptarmigan, goose eggs), Arctic char and fish roe as main exposure sources. CONCLUSIONS: Increased country food consumption was strongly associated with higher PFAAs concentrations, particularly PFOS and long-chain PFAAs congeners. The results provide further evidence that Arctic communities are disproportionately impacted by PFAAs, and further national and international regulations are required to protect the exceptional quality of country foods. KEYWORDS: PFAS; exposure; food; Indigenous

Elevated exposure to long-chain perfluoroalkyl and polyfluoroalkyl substances (PFAS) in Inuit from Nunavik, Arctic Canada: a call for global action

BACKGROUND AND AIM: The Inuit of Nunavik are exposed to perfluoroalkyl acids (PFAAs) via long-rang transport from southern to northern latitudes and biomagnification of PFAAs in Arctic food webs. Our objective was to document plasma PFAAs levels and compare them to previously documented levels and the general Canadian population. METHODS: The study included 1326 Nunavimmiut aged 16-82 years from the population representative survey, Qanuilirpitaa? 2017 Nunavik Inuit Health Survey. Concentrations of nine PFAAs were assessed, including perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA) and perfluoroundecanoic acid (PFUdA). Concentrations were compared to Nunavik levels in 2004, other Arctic regions, and the Canadian Health Measures Survey (CHMS) Cycle 5 2016-2017. Multiple linear regression analyses compared concentrations by demographics and lifestyle. RESULTS: There were elevated concentrations of various PFAAs congeners compared to CHMS, including PFOS, and long-chain PFAS congeners, PFNA, PFDA, and PFUnDA. PFNA and PFUdA concentrations were 7-fold higher than the CHMS concentrations, and PFDA concentrations were almost 4-fold higher than the CHMS concentrations. Short-chain congeners were largely undetected. Concentrations differed by sex, age, region, and indicators of seafood and marine mammal consumption. Males had higher concentrations of PFOA and PFHxS, whereas females had higher concentrations of PFDA and PFUdA. PFAAs concentrations increased with age and were highest among those aged 50+ years, such that serum PFOS concentrations were 2.5 times higher in those aged 50+ years compared to those aged 16-29 years. PFNA concentrations followed a U-shaped curve with increasing age. CONCLUSIONS: Our findings indicate a decrease in older PFAAs, but concentrations of many PFAAs in Nunavik remain several-fold higher compared to the general Canadian population. Evidence also points to an increase in exposure to long-chain PFAAs, which are an emerging public health concern in the Arctic. KEYWORDS: PFAS, Indigenous, Environmental justice, Exposure

Evaluation of the ecological impacts of short- and long-chain perfluoroalkyl acids on constructed wetland systems: Perfluorobutyric acid and perfluorooctanoic acid

Perfluoroalkyl substances (PFASs) contamination of aquatic system has attracted widespread attention in recent years. From both plant and microbial perspectives, the ecological risk of CWs by comparing PFASs with different chain lengths have not been fully understood. In this study, the influences of perfluorobutyric acid (PFBA) and perfluorooctanoic acid (PFOA) as typical of short- and long-chains on the ecological effect of CWs have been specifically studied. The results showed that plants produced oxidative stress response and the activities of superoxide dismutase (SOD) and peroxidase (POD) in leaves were stimulated by 17.23–28.13% and 10.49–14.17% upon 10 mg/L PFBA and PFOA exposure. Under the high level of PFBA and PFOA stress, the chlorophyll content was reduced by 15.20–39.40% and lipid peroxidation was observed in leaves with the accumulation of malondialdehyde (MDA) at 1.20–1.22 times of the control. Dehydrogenase (DHA) exhibited the most sensitivity in the presence of PFBA and PFOA with an inhibition ratio of over 90%. The biotoxicity of PFOA was higher than that of PFBA in terms of the inhibition degree of several substrate enzymes. The information of Illumina Miseq sequencing indicated that the diversity and structure of microbial community in CWs were significantly altered by PFBA and PFOA addition and led to an enrichment of more PFASs-tolerant bacteria.

Potential disruption of thyroid hormones by perfluoroalkyl acids in an Arctic seabird during reproduction

Arctic marine ecosystems are experiencing rapid change, such as ocean warming and enhanced pollutants. Perfluoroalkyl acids (PFAAs) arriving via long-range transport have been detected in Arctic wildlife, including seabirds which are considered sentinels of marine ecosystem health. There is evidence that PFAA exposure leads to the disruption of thyroid hormones (THs), such as thyroxine (T4) and triiodothyronine (T3), which play important roles in metabolism, incubation, and thermoregulation in seabirds. Here, we investigated relationships between PFAAs and THs [total T4 (TT4), free T4 (FT4), total T3 (TT3) and free T3 (FT3)] in blood plasma collected from 63 thick-billed murres (Uria lomvia) at a colony located in northern Hudson Bay (2016–2018). We then tested if PFAAs and TH levels were related to fitness-associated reproductive traits, such as body mass and hatch dates. PFUdA, PFOS, and PFTrDA were the dominant PFAAs in murre blood, accounting for approximately 77% of ∑PFAA. Females had higher PFAAs than males, possibly due to higher trophic feeding. While FT3 increased with PFOS, PFNA, PFDA, PFDoA, PFTeDA, ∑PFCA7, and ∑PFAA in murres, TT3 decreased with PFOS, PFDoA, and PFTeDA in males, but not females, suggesting thyroid disruption. TT3 increased with body mass, whereas several long-chain PFAAs were negatively correlated with body mass. Negative relationships between PFNA, PFDoA, PFTrDA, PFTeDA, and ∑PFAA with hatch dates may be the result of a disruption in incubation behaviour, resulting in earlier hatch dates. Consequently, TT3 concentrations were highest in males and females in 2018, a year in which PFAAs were lowest and hatch dates were delayed relative to 2017. As an Arctic seabird experiencing several indirect effects of climate change, the interaction of PFAAs on thyroid activity may cause additional stress to murres.