Abstract  Perfluoroalkyl substances (PFAS) are contaminants that are applied in a wide range of consumer products, including ski products. The present study investigated the neuro-dopamine (DA) and cellular steroid hormone homeostasis of wild Bank voles (Myodes glareolus) from a skiing area in Norway (Trondheim), in relation to tissue concentrations of PFAS. We found a positive association between brain DA concentrations and the concentration of several PFAS, while there was a negative association between PFAS and dopamine receptor 1 (dr1) mRNA. The ratio between DA and its metabolites (3,4-dihydroxyphenylacetic acid: DOPAC and homovanillic acid: HVA) showed a negative association between DOPAC/DA and several PFAS, suggesting that PFAS altered the metabolism of DA via monoamine oxidase (Mao). This assumption is supported by an observed negative association between mao mRNA and PFAS. Previous studies have shown that DA homeostasis can indirectly regulate cellular estrogen (E2) and testosterone (T) biosynthesis. We found no association between DA and steroid hormone levels, while there was a negative association between some PFAS and T concentrations, suggesting that PFAS might affect T through other mechanisms. The results from the current study indicate that PFAS may alter neuro-DA and steroid hormone homeostasis in Bank voles, with potential consequences on reproduction and general health.

Abstract  Background There is increasing global concern regarding the health impacts of perfluoroalkyl and polyfluoroalkyl substances (PFAS), which are emerging environmental endocrine disruptors. Results from previous epidemiological studies on the associations between PFAS exposure and sex hormone levels are inconsistent. Objective We examined the associations between serum PFAS compounds (PFDeA, PFHxS, PFNA, PFOA, PFOS) and sex hormones, including total testosterone (TT), free testosterone (FT), estradiol (E), and serum hormone binding globulin (SHBG). Results After adjusting for potential confounders, PFDeA, PFOS, and PFHxS exposures were significantly associated with increased serum testosterone concentrations in males. PFDeA, PFOA, and PFOS exposures were positively correlated with FT levels in 20-49-year-old women, while PFOS exposure was negatively associated with TT levels in 12-19-year-old girls. PFAS exposure was negatively associated with estradiol levels including: PFDeA in all females, PFHxS, PFNA, PFOS, and PFOA in 12-19-year-old girls, PFNA in women above 50 years, and PFOA in 12-19-year-old boys, while PFDeA and PFOS exposures were positively associated with estradiol levels in these boys. n-PFOS exposure was positively associated with SHBG levels in men older than 20 and in all females. Conclusions Using a large cohort of males and females aged from 12 to 80, we found that PFAS exposure appears to disrupt sex hormones in a sex-, age-, and compound-specific manner. Future work is warranted to clarify the causality and mechanisms involved.

Abstract  Twelve perfluoroalkyl substances (PFASs) were analyzed in tap waters collected from 10 different cities in Sichuan Province using an ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The results show that ∑PFASs in Yibin area displayed the highest concentration level at 41.2 ng•L-1, while Mianyang had the lowest concentration (4.17 ng•L-1). Perfluroroocantanoic acid (PFOA) was the predominant PFASs in tap waters of Sichuan Province, which accounted for 28%~89% of ∑PFASs with an exception of Yibin (8.6%), followed by perfluorohexanoate (PFHxA), perfluorooctane sulfonate (PFOS) and perfluorononanoate (PFNA). It suggests that short- and median-chain PFASs (C≤10) were the main contaminants in tap water. Finally, risk quotients (RQs) were calculated and it was found that RQs values of PFOA, PFOS, PFHxS, PFBS and PFHxA were lower than 1 in all the tap waters, suggesting no direct health risk to local residents. © 2019, Science Press. All right reserved.

Abstract  In Volume 30, in the article, “Six Pilot-Scale Studies Evaluating the In Situ Treatment of PFAS in Groundwater” by Rick McGregor the following changes were made 1)In the abstract the units for the concentration of various PFAS compounds were reported as ug/L, they should be ng/L and read: “24,000 ng/L perfluoropentanoic acid (PFPeA), up to 6,200 ng/L pentafluorobenzoic acid (PFBA), 16,100 ng/L perfluorohexanoic acid (PFHxA), up to 6,080 ng/L perfluoroheptanoic acid (PFHpA), up to 450 ng/L perfluorooctanoic acid (PFOA) and up to 140 ng/L perfluorononanoic acid (PFNA)” 2)In the abstract pentafluorobenzoic acid should be read “perfluorobutanoic acid” 3)On page 41 pentafluorobenzoic acid should be changed to “perfluorobutanoic acid”. These errors were introduced during the writing process and do not affect any of the results presented. © 2020 Wiley Periodicals LLC

Abstract  Contamination profiles of 11 kinds of perfluorinated compounds (PFCs) were analyzed by using ultra high performance liquid chromatography-triple quadrupole mass spectrometry in water and sediment samples of Hanjiang River in dry and wet seasons. The results showed that 11 kinds of PFCs were all detected. The total concentrations of PFCs in water and sediment were 0.3-23.04 ng/L, 0-55.1 ng/g in dry season and 0.16-19.68 ng/L, 0.99-85.07 ng/g in wet season. The maximum concentration of PFCs was detected in Wuhan where Hanjiang River feeds into Yangtze River. Meanwhile, Wuhan had the highest concentration of perfluorooctanoic acid (PFOA) with 22.52 ng/L in dry season and 12.52 ng/L in wet season. Perfluoroheptanoic acid (PFHpA) and perfluorohexanoic acid (PFHxA) were the dominant PFCs in sediment and the highest total concentration of PFCs was detected in Taocha. There was little difference in the concentration composition of ∑PFCs in sediment in both seasons. The risk quotient method was used for the ecological risk assessment of PFOA, perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA), PFHxA and perfluorodecanoic acid (PFDA) in water, and PFOA and PFOS in sediment based on the measured environmental concentration (MEC) and the predicted non-effect concentration (PNEC) of target pollutants. The assessment results suggest that the above PFCs in water and sediment of Hanjiang River posed no ecological risk to environment. © 2017 Peking University.

Abstract  Aerobic biotransformation of 6-2 fluorotelomer alcohol (6-2 FTOH, F(CF2)6CH2CH2OH) was studied in a closed bottle system with activated sludge for the first time. The concentrations of 6-2 FTOH and metabolites were determined during the test period (28 days) and biodegradation rates at each sampling time were calculated. The target compounds were not only measured in activated sludge and water phase, but also in headspace and septa because the parent compound and some metabolites are highly volatile. The results indicated that 6-2 FTOH was ready to degrade in activated sludge, and the half-time of 6-2 FTOH was 0.9 day. Large quantity of 6-2 fluorotelomer carboxylic acid (6-2 FTCA) and 6-2 fluorotelomer unsaturated carboxylic acid (6-2 FTUCA) were produced at the beginning of experiment, and their molar yields were 25.4% and 10.8% at 24 h, respectively. Along with the degradation, 6-2 FTCA and 6-2 FTUCA were further transformed to other metabolites with the final molar yields of 0% and 1.2%, respectively. 5-3 polyfluorinated acid (5-3 FTCA) and 5-2 secondary fluorotelomer alcohol (5-2s FTOH) were the primary metabolites at 28 d and their molar yields were 23.4% and 17.6%, respectively. The final molar yield of perfluorohexanoic acid (PFHxA) was 1.3%, which was lower than that in soil or mixed bacteria culture system in other studies. At Day 28, 5.5% of 6-2 FTOH were still detectable in the closed bottle system. Based on the results of this study, monitoring and toxicity test on the stable metabolites of FTOH degradation should be strengthened so as to make a comprehensive risk assessment of 6-2 FTOH.

Abstract  In order to assess the feasibility of typical plants as bioindicators for perfluorinated chemicals (PFCs), the residues of 13 PFCs in fresh leaves of moss, camphor tree, masson pine, gladiolus, lichen, alfalfa, silky oak and rhododendron were measured by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Moss, which accumulates PFCs most effectively among the eight, was selected as the environmental bioindicator for PFCs assessment. The total fluorine, extractable organic fluorine and PFCs in moss from 12 locations of six Shenzhen districts, including Bao'an, Nanshan, Futian, Yantian, Luohu and Longgang, were measured by cyclic neutron activation analysis combined with HPLC-MS/MS. Results showed that EOF accounted for 13.4%-16.5% of TF. They indicated that inorganic fluorine was the main form. Only 0.08%-0.15% of EOF was the identified fluorine while more than 99.8% of EOF required further identification. The sum of perfluorooctane sulfonate, perfluorooctanoic acid and perfluorohexanoic acid accounted for 88%-99% of total PFCs, making them the main PFCs species in moss. Total PFCs residues in moss from Bao'an district were significantly higher than those from other districts (P<0.01), which was likely due to the presence of PFCs-related industries, geographical location and climate. The results suggest that moss is a feasible bioindicator for PFCs and its exposure risk in the environment.

Abstract  A discussion on the environmental fate of fluorosurfactants covers the development and use of aqueous film forming foams for extinguishing hazardous hydrocarbon-fuel fires; development of an analytical method to quantitatively determine perfluorinated surfactants in groundwater; application of the method in analyzing sets of groundwater samples from abandoned fire-training areas in military installations around the US (Naval Air Station Fallon, NV; Tyndall Air Force Base (AFB); and Wurtsmith AFB); derivatization of the perfluorocarboxylates by the solid phase extraction and the in-vial elution and derivatization technique; and the detection of perfluorocarboxylates (perfluorohexanoate, perfluoroheptanoate, and perfluorooctanoate) from groundwater analyses of samples, showing proof that this class of perfluorinated surfactants is not readily biodegradable.

Abstract  With this Correction, we would like to improve the specificity in our per- and polyfluoroalkyl substances (PFASs) terminology. PFASs are either nondegradable or degrade to form nondegradable terminal degradation products, usually (although not always) the perfluoroalkyl or perfluoroalkyl(poly)ether acids (collectively termed PFAAs by Wang et al.1). Our focus lies on the perfluoroalkyl acids, and it is those that are referred to in the published paper when the abbreviation PFAA is used. Our framework covers nonpolymeric and polymeric perfluoroalkane-sulfonyl-fluoride- (PASF-) and fluorotelomer-based PFASs. The polymeric substances included in the framework are the side-chain fluorinated polymers that are considered precursors to PFAAs. The nonpolymeric substances included in our framework are the low-molecular-weight precursors to PFAAs and the PFAAs themselves. The substances covered by our framework are summarized in Table 1 of the published paper. Fluoropolymers or perfluoropolyethers were not considered in our framework. For example, we would like to point out that in the statement that our LCIA framework can be applied to the “vast majority of PFASs on the market”, and elsewhere in the article, we were not considering fluoropolymers or perfluoropolyethers, which comprise a significant production volume fraction of the PFASs on the market. Consideration of the LCIA of a wider range of PFASs, including fluoropolymers and perfluoropolyethers, would be a valuable extension of our framework. Furthermore, in Section 3.3, it was stated that no emissions of PFASs were included in the commercial LCI data set. Whereas emissions of shorter chain perfluoroalkyl substances were included (with one to three carbon atoms), emissions of PFHxA and its precursors were not. We would also like to clarify that f in eq 2 is a mass fraction, as the characterization factor (CF) is expressed per kilogram emitted. In Table 1, the transformation fraction is given as a molar yield, which is to be transformed into a mass yield. In footnote a in Table 1, this is described as the weight fraction of the primary pollutant that is made up of the PFAA. A clearer description would be that the quotient between the molar weights (M (g/mol)) of the precursor (the primary pollutant) and the PFAA is to be applied. Note that when the primary pollutant x is a side-chain fluorinated polymer, the M of the repeating unit is applied. This has been clarified in a corrected version of the Supporting Information (SI). In addition, the SI was made consistent with model calculations: Table S15 was updated to reflect the fact that LCI data for the DWR-treated drape are per square meter not per kg textile (correspondingly, the C6 copolymer amount per functional unit reported in the main paper (Section 3.3) should be 0.001 kg), Section S4.1.2 was updated with a corrected formula, Sections S5.1 and S5.3 were updated with the correct KDOC, and Section S5.4 was updated with relevant information regarding PFOS. © 2020 American Chemical Society. All rights reserved.

Abstract  Perfluoroalkyl and polyfluoroalkyl substances (PFASs) and organophosphate flame retardants (OPFRs) are chemicals that may contribute to placenta-mediated complications and adverse maternal-fetal health risks. Few studies have investigated these chemicals in relation to biomarkers of effect during pregnancy. We measured 12 PFASs and four urinary OPFR metabolites in 132 healthy pregnant women during mid-gestation and examined a subset with biomarkers of placental development and disease (n = 62). Molecular biomarkers included integrin alpha-1 (ITGA1), vascular endothelial-cadherin (CDH5), and matrix metalloproteinase-1 (MMP1). Morphological endpoints included potential indicators of placental stress and the extent of cytotrophoblast (CTB)-mediated uterine artery remodeling. Serum PFASs and urinary OPFR metabolites were detected in ∼50-100% of samples. The most prevalent PFASs were perfluorononanoic acid (PFNA), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonic acid (PFOS), with geometric mean (GM) levels of ∼1.3-2.8 (95% confidence limits from 1.2-3.1) ng/mL compared to ≤ 0.5 ng/mL for other PFASs. Diphenyl phosphate (DPhP) and bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) were the most prevalent OPFR metabolites, with GMs of 2.9 (95% CI: 2.5-3.4) and 3.6 (95% CI: 2.2-3.1) ng/mL, respectively, compared to < 1 ng/mL for bis(2-chloroethyl) phosphate (BCEP) and bis(1-chloro-2-propyl) phosphate (BCIPP). We found inverse associations of PFASs or OPFRs with ITGA1 or CDH5 immunoreactivity and positive associations with indicators of placental stress in multiple basal plate regions, indicating these chemicals may contribute to abnormal placentation and future health risks. Associations with blood pressure and lipid concentrations warrant further examination. This is the first study of these chemicals with placental biomarkers measured directly in human tissues and suggests specific biomarkers are sensitive indicators of exposure during a vulnerable developmental period.

Abstract  Perfluoroalkyl acids (PFAAs) have been ubiquitously detected in water bodies and are a cause of great public concern due to their adverse effects. This study investigated the long-term temporal-spatial trends of PFAAs in the water bodies of the entire Taihu Lake, and predicted PFAA concentrations for 2024. A field investigation conducted in 2021 and previous data allowed to derive trends over a broad temporal-spatial scale, which is often not feasible in short-term studies. In the 2009-2021 period, the most quantifiable PFAAs increased, among which perfluorooctanoic acid and perfluorohexanoic acid were predominant. As of 2021, the mean total concentration of ten PFAAs (∑10PFAA) showed a distinct spatial decreasing trend, moving from north to south within the lake, and similar spatial distribution patterns were also noted in other years. The main PFAA input and most serious contamination were concentrated in the northern region, due to the riverine inputs and clustering of PFAA-related industries. The ∑10PFAA concentration in the wet season was greater and presented a more uniform distribution pattern than that in the dry season, possibly due to the combined effects of the degradation of PFAA precursors, water inflow, rainfall, shipping activities, and a shallow water column. From 2009 to 2021 the ∑10PFAA concentration of the entire lake showed an increasing trend, but the rate of increase was significantly reduced. In addition, a grey model predicted that the mean ∑10PFAA concentration in the entire Taihu Lake will reach 431 ng/L in 2024, and the northern region will be affected by a more serious PFAA pollution in the future because it exhibited a high mean ∑10PFAA concentration of 426 ng/L in 2021. These findings provide novel insights into the temporal-spatial distribution of PFAAs in Taihu Lake, and could help regulators to formulate policy decisions in response to PFAA pollution.

Abstract  This commentary presents a scientific basis for managing as one chemical class the thousands of chemicals known as PFAS (per- and polyfluoroalkyl substances). The class includes perfluoroalkyl acids, perfluoroalkylether acids, and their precursors; fluoropolymers and perfluoropolyethers; and other PFAS. The basis for the class approach is presented in relation to their physicochemical, environmental, and toxicological properties. Specifically, the high persistence, accumulation potential, and/or hazards (known and potential) of PFAS studied to date warrant treating all PFAS as a single class. Examples are provided of how some PFAS are being regulated and how some businesses are avoiding all PFAS in their products and purchasing decisions. We conclude with options for how governments and industry can apply the class-based approach, emphasizing the importance of eliminating non-essential uses of PFAS, and further developing safer alternatives and methods to remove existing PFAS from the environment.

Abstract  Background: Per- and polyfluoroalkyl substances (PFAS) are a large class of synthetic (man-made) chemicals widely used in consumer products and industrial processes. Thousands of distinct PFAS exist in commerce. The 2019 U.S. Environmental Protection Agency (U.S. EPA) Per- and Polyfluoroalkyl Substances (PFAS) Action Plan outlines a multiprogram national research plan to address the challenge of PFAS. One component of this strategy involves the use of systematic evidence map (SEM) approaches to characterize the evidence base for hundreds of PFAS. Objective: SEM methods were used to summarize available epidemiological and animal bioassay evidence for a set of ~150 PFAS that were prioritized in 2019 by the U.S. EPA's Center for Computational Toxicology and Exposure (CCTE) for in vitro toxicity and toxicokinetic assay testing. Methods: Systematic review methods were used to identify and screen literature using manual review and machine-learning software. The Populations, Exposures, Comparators, and Outcomes (PECO) criteria were kept broad to identify mammalian animal bioassay and epidemiological studies that could inform human hazard identification. A variety of supplemental content was also tracked, including information on in vitro model systems; exposure measurement-only studies in humans; and absorption, distribution, metabolism, and excretion (ADME). Animal bioassay and epidemiology studies meeting PECO criteria were summarized with respect to study design, and health system(s) were assessed. Because animal bioassay studies with ≥21-d exposure duration (or reproductive/developmental study design) were most useful to CCTE analyses, these studies underwent study evaluation and detailed data extraction. All data extraction is publicly available online as interactive visuals with downloadable metadata. Results: More than 40,000 studies were identified from scientific databases. Screening processes identified 44 animal and 148 epidemiology studies from the peer-reviewed literature and 95 animal and 50 epidemiology studies from gray literature that met PECO criteria. Epidemiological evidence (available for 15 PFAS) mostly assessed the reproductive, endocrine, developmental, metabolic, cardiovascular, and immune systems. Animal evidence (available for 40 PFAS) commonly assessed effects in the reproductive, developmental, urinary, immunological, and hepatic systems. Overall, 45 PFAS had evidence across animal and epidemiology data streams. Discussion: Many of the ~150 PFAS were data poor. Epidemiological and animal evidence were lacking for most of the PFAS included in our search. By disseminating this information, we hope to facilitate additional assessment work by providing the initial scoping literature survey and identifying key research needs. Future research on data-poor PFAS will help support a more complete understanding of the potential health effects from PFAS exposures.

Abstract  Recently, perfluorohexanoic acid (PFHxA), an emerging contaminant, has been detected at a high level in the water environment. Its possible presence in drinking water treatment process thus suggests that removal technique should be developed. In this study, one reverse osmosis (RO) membrane, two nanofiltration (NF) membranes and two ultrafiltration (UF) membranes were tested to reject PFHxA (100 - 300 ng/L) in pure water. The measured molecular weight cut-off (MWCO) of two NF membranes were as large as 10,000 and 27,000 Da, while they were still able to reject 96.3% and 95.3% PFHxA in pure water, respectively. This indicates PFHxA rejection rate was not dependent on the MWCO of membrane. Results also show that membrane with more negative zeta-potential tends to have higher rejection rate to PFHxA in pure water, suggesting that electrical repulsion between PFHxA and membrane might play an important role in PFHxA rejection. In conclusion, NF membranes would be a better option for removing PFHxA from drinking water than RO membrane because of their larger pure water permeability and NaCl transmission. © 2017 Japan Society on Water Environment.

Abstract  Timely diagnosis and treatment of thyroid dysfunction is compelling given the prevalence and severity of the disease. It requires reliance on adequate laboratory testing of serum TSH as a hallmark in combination with free thyroxine/triiodothyronine. Free hormone methods have to accommodate variations in the concentration and binding capacity of binding proteins. This is a challenge because none of the methodologies developed so far measures the actual unbound hormone in serum. The indirect methods provide an approximation while the direct ones estimate the free hormone concentration either in the presence of the protein-bound counterpart, or after physical separation of the free from bound fraction. The ongoing controversy on the validity and lack of comparability of methodologies points to their imperfectness to reflect real in-vivo free hormone concentrations. Therefore, laboratories and clinicians should know the window of validity and limitations of their methods. The recently developed reference measurement system is a key advance towards improved standardization and clinical validity of free thyroid hormone measurements.

Abstract  Per- and polyfluoroalkyl substances (PFAS) have received continuous attention; however, there is limited understanding of their sources in the atmosphere and related human exposure risks. This study measured PFAS in the atmospheric total suspended particles collected from Karachi, Pakistan, during the winter. Among the quantified PFAS, perfluorobutanoic acid (PFBA) showed the highest average concentration (3.11 ± 2.64 pg/m3), accounting for 32% of the total PFAS. Wind speed was positively correlated with perfluorohexanoic acid (PFHxA) and N-ethyl perfluorooctanesulfonamide (N-EtFOSA), while relative humidity was negatively correlated with perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). Weighted potential source contribution function (WPSCF) and concentration weighted trajectory (WCWT) analyses suggested that northwestern Pakistan and western Afghanistan areas were highly associated with the long-range atmospheric transport of PFAS. We also calculated the daily intake of PFAS via inhalation, which were in the range of 0.07-3.98 and 0.01-0.33 pg/kg bw/d for children and adults, respectively. The calculated hazard quotient (HQ) of PFOS and PFOA was significantly lower than 1, indicating less or unlikely to cause non-carcinogenic effect via inhalation exposure. Overall, this study contributes to the understanding of geographic origins and human inhalation risks of airborne PFAS on a regional scale.

Abstract  For decades, perfluoroalkyl acids (PFAAs) have been commonly used for industrial and commercial purposes due to their water- and stain-resistant properties. Persistent pollutants that contain PFAAs have been associated with adverse health effects in humans, and many studies have documented dietary intake, indoor air inhalation, and dermal contact as the potential routes for human exposure to PFAAs. The aim of this study was to assess the level of PFAAs in the serum samples of a general population in a specific region in Malaysia. Using 219 serum samples collected from residents of Klang Valley, Malaysia, the levels of nine PFAAs were analyzed using liquid chromatography-tandem mass spectrometry. In addition, questionnaire surveys on the dietary habits and lifestyles of the subjects were conducted. The results showed that PFAA concentrations of up to 32.57 ng/mL were detected in all serum samples. In 82.6% of the participants, at least seven PFAAs were detected in the serum samples, with perfluorooctanesulfonic acid being the predominant PFAA (median = 8.79 ng/mL). In the adjusted regression model, the concentrations of most PFAAs were higher in men than in women and positively correlated with age, although body mass index and smoking were not significantly associated with the serum PFAA concentrations. Taking into consideration the lifestyle variables, significant associations were found between nonstick cookware and perfluorononanoic acid, between dental floss and cosmetics and perfluorodecanoic acid (PFDA), and between leather sofa and perfluoroundecanoic acid (PFUnDA). Besides, consumption of beef was significantly associated with increased levels of serum PFUnDA, whereas consumption of lamb and chicken eggs was negatively associated with the serum levels of PFUnDA and PFDA, respectively.

Abstract  Poly- and perfluoroalkyl substances (PFASs) are a large group of chemicals commonly used in various branches of industry, which may adversely affect the living organisms. The aim of this study were to evaluate exposure of dogs to six selected PFASs: five perfluoroalkyl carboxylic acids (perfluorobutanoic acid - PFBuA, perfluoropentanoic acid - PFPeA, perfluorohexanoic acid - PFHxA, perfluoroheptanoic acid - PFHpA, perfluorooctanoic acid - PFOA) and perfluorooctane sulfonic acid (PFOS) through the analysis of fur samples. To our knowledge this is the first study concerning the use of fur samples to evaluation of exposure of domestic animals to PFASs. Relationship between PFASs concentration and age, gender and body weight of animals was also evaluated. Fur samples were collected from 30 dogs living in Olsztyn (Poland). All PFASs studied were detected in the canine fur samples. The highest concentrations were observed in the case of PFOA and PFBuA, detected at concentrations in the range between 1.51 and 66.7 ng/g and 0.98-26.6 ng/g, respectively. During the present study generally no statistically significant differences dependent on gender, age and body weight of animals were found. This study confirms the suitability of fur samples for biomonitoring of exposure to PFASs in domestic animals, what may be important in veterinary toxicology.

Abstract  Polyfluoroalkyl substances and perfluoroalkyl substances (PFAS) are a family of anthropogenic chemicals that are used in food packaging, waterproof clothing, and firefighting foams for their water and oil resistant properties. Though levels of some PFAS appear to be decreasing in Canada's south, environmental levels have been increasing in the Arctic due to long-range transport. However, the implications of this on human exposures in sub-Arctic and Arctic populations in Canada have yet to be established. To address this data gap, human biomonitoring research was completed in Old Crow, Yukon, and the Dehcho region, Northwest Territories. Blood samples were collected from adults residing in seven northern First Nations and were analyzed by liquid chromatography mass spectrometry. A total of nine PFAS were quantified: perfluorooctanoic acid (PFOA), perfluorooctane sulphonic acid (PFOS), perfluorohexane sulphonic acid (PFHxS), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUdA), perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), and perfluorobutane sulphonic acid (PFBS). In the Dehcho (n = 124), five PFAS had a detection rate greater than 50% including PFOS, PFOA, PFHxS, PFNA, and PFDA. In addition to these PFAS, PFUdA was also detected in at least half of the samples collected in Old Crow (n = 54). Generally, male participants had higher concentrations of PFAS compared to female participants, and PFAS concentrations tended to increase with age. For most PFAS, Old Crow and Dehcho levels were similar or lower to those measured in the general Canadian population (as measured through the Canadian Health Measures Survey or CHMS) and other First Nations populations in Canada (as measured through the First Nations Biomonitoring Initiative or FNBI). The key exception to this was for PFNA which, relative to the CHMS (0.51 μg/L), was approximately 1.8 times higher in Old Crow (0.94 μg/L) and 2.8 times higher in Dehcho (1.42 μg/L) than observed in the general Canadian population. This project provides baseline PFAS levels for participating communities, improving understanding of human exposures to PFAS in Canada. Future research should investigate site-specific PFNA exposure sources and monitor temporal trends in these regions.

Abstract  Chlorinated ethenes such as trichloroethene (TCE), cis-1,2-dichloroethene (cis-1,2-DCE), and vinyl chloride along with per- and polyfluoroalkyl substances (PFAS) have been identified as chemicals of concern in groundwater; with many of the compounds being confirmed as being carcinogens or suspected carcinogens. While there are a variety of demonstrated in-situ technologies for the treatment of chlorinated ethenes, there are limited technologies available to treat PFAS in groundwater. At a former industrial site shallow groundwater was impacted with TCE, cis-1,2-DCE, and vinyl chloride at concentrations up to 985, 258, and 54 µg/L, respectively. The groundwater also contained maximum concentrations of the following PFAS: 12,800 ng/L of perfluoropentanoic acid, 3,240 ng/L of perfluorohexanoic acid, 795 ng/L of perfluorobutanoic acid, 950 ng/L of perfluorooctanoic acid, and 2,140 ng/L of perfluorooctanesulfonic acid. Using a combination of adsorption, biotic, and abiotic degradation in situ remedial approaches, the chemicals of concern were targeted for removal from the groundwater with adsorption being utilized for PFAS whereas adsorption, chemical reduction, and anaerobic biodegradation were used for the chlorinated ethenes. Sampling of the groundwater over a 24-month period indicated that the detected PFAS were treated to either their detection, or below the analytical detection limit over the monitoring period. Postinjection results for TCE, cis-1,2-DCE, and vinyl chloride indicated that the concentrations of the three compounds decreased by an order of magnitude within 4 months of injection, with TCE decreasing to below the analytical detection limit over the 24-month monitoring period. Cis-1,2-DCE, and vinyl chloride concentrations decreased by over 99% within 8 months of injections, remaining at or below these concentrations during the 24-month monitoring period. Analyses of Dehalococcoides, ethene, and acetylene over time suggest that microbiological and reductive dechlorination were occurring in conjunction with adsorption to attenuate the chlorinated ethenes and PFAS within the aquifer. Analysis of soil cores collected pre- and post-injection, indicated that the distribution of the colloidal activated carbon was influenced by small scale heterogeneities within the aquifer. However, all aquifer samples collected within the targeted injection zone contained total organic carbon at concentrations at least one order of magnitude greater than the preinjection total organic carbon concentrations. © 2021 Wiley Periodicals LLC

Abstract  It is estimated that many organic compounds found in our environment can interfere with the thyroid system and act as thyroid hormone (TH) disruptor. Despite that, there is a clear lack of assays to identify TH disruptors. Recently zebrafish embryos were suggested as screening tool to identify compounds which impact thyroid synthesis. Effects on hormone level, gene transcript expression, eye development and swim bladder inflation are suggested as potential biomarker for TH disruptors. In order to assess the applicability of these biomarkers we performed a literature review. The effects of 25 known TH disrupting compounds were compared between studies. The studies were limited to exposures with embryos prior 7 days of development. The different study designs and the lack of standardized methods complicated the comparison of the results. The most common responses were morphological alterations and gene transcript expression changes, but no specific biomarker for TH disruption could be identified. In studies addressing TH disruption behavioral effects were more commonly monitored than in studies not mentioning the TH pathway. TH disruption in developing zebrafish embryos might be caused by different modes of action e.g. disruption of follicle development, binding of TH, activation of TH receptors causing different effects. Timing of developmental processes in combination with exposure duration might also play a role. On the other side compound characteristics (uptake, stability, metabolization) could also cause differences between substances. Further studies are necessary to gain better understanding into the mechanisms of TH disruption in early zebrafish development.

Abstract  The findings of per- and polyfluoroalkyl substances (PFAS) in humans and the environment all over the world have raised concerns and public awareness for this group of man-made chemicals. In the last three decades, this led to different regulatory restrictions for specific PFAS as well as shifts in the production and usage of these substances. In this study, we analyzed the PFAS levels of 100 human blood plasma samples collected from 2009 to 2019 for the German Environmental Specimen Bank (ESB) to further elucidate the time course of exposure towards this substance group as shown by Schröter-Kermani et al., (2013) with samples from 1982 to 2010. A spectrum of 37 PFAS, including perfluorocarboxylic (PFCA) and -sulfonic acids (PFSA) as well as potential precursors and substitutes like ADONA, GenX or F-53B was analyzed by UHPLC coupled with high-resolution mass spectrometry. Validation was successful for 33 of the substances. The two legacy substances perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were detected in every sample of the 2009-2019 dataset and showed the highest concentrations with ranges of 0.27-14.0 ng/mL and 1.21-14.1 ng/mL, respectively. A significant portion of total PFOS analytes was present as branched isomers (mean: 34 ± 7%). High detection frequencies of 95% and 82% were also found for perfluorohexane sulfonic acid (PFHxS) and perfluorononanoic acid (PFNA), respectively, but in lower concentrations (PFHxS:

Abstract  Contamination and adverse effects from various pollutants often appear in abandoned industrial regions. Thus, nine groundwater samples were collected from the vicinity of the fluorochemical industry in Fuxin City, Liaoning Province, to determine concentrations of the ten heavy metals arsenic (As), chromium (Cr), cadmium (Cd), lead (Pb), nickel (Ni), copper (Cu), manganese (Mn), zinc (Zn), iron (Fe) and mercury(Hg), as well as those of fluorine (F-) and eighteen poly- and perfluorinated substances (PFASs), analyse correlation relationships, and assess the health risks for different age groups. The results showed that the levels of fluorine (F-) (0.92-4.42 mg·L-1), Mn (0.0005-4.91 mg·L-1) and Fe (1.45-5.61 mg·L-1) exceeded the standard limits for drinking water. Short chain perfluorobutanoic acid (PFBA) (4.14-2501.42 ng·L-1), perfluorobutane sulfonate (PFBS) (17.07-51,818.61 ng·L-1) and perfluorohexanoic acid (PFHxA) (0.47-936.32 ng·L-1) were the predominant substances from the PFASs group. No individual PFASs levels had significant relationships with F- or heavy metal contents. There was a positive relationship between short chain PFASs concentrations and water depth and a negative relationship between long chain PFASs concentration and water depth. The hazard quotient (HQ) decreased in the order F- > heavy metals > PFASs and also decreased for older age groups. In addition, As, Fe, Mn and perfluorooctanoic acid (PFOA) were the main sources of risk from the heavy metal and PFASs groups, respectively.