Abstract  Perfluoroalkyl substances (PFAS) are persistent bio-accumulative chemicals that impact the health of pregnant women and their children. PFAS derive from environmental and consumer products, which depend on human lifestyle, socioeconomic characteristics, and time variation. Here, we aimed to explore the temporal trends of PFAS in pregnant women and the characteristics related to maternal PFAS concentration. Our study is part of the Hokkaido Study on Environment and Children's Health, the Hokkaido large-scale cohort that recruited pregnant women between 2003 and 2011. Blood samples were acquired from pregnant women during the third trimester to measure PFAS and cotinine concentrations. Maternal basic information was collected with a baseline structured questionnaire. Eleven PFAS were measured from 2123 samples with ultra-performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry. Eight PFAS were above 80% detection rate and were included in the final analysis. We used multivariable linear regression to analyze the association of pregnant women characteristics with the levels of eight PFAS. The temporal trend of PFAS was observed in two periods (August 2003 to January 2006 and February 2006 to July 2012). The concentration of perfluorooctane sulfonate (PFOS) significantly decreased from August 2003 to January 2006 and from February 2006 to July 2012. The concentrations of perfluorododecanoic acid (PFDoDA), perfluoroundecanoic acid (PFUnDA), and perfluorotridecanoic acid (PFTrDA) increased significantly between August 2003 and January 2006, whereas they decreased significantly between February 2006 and July 2012. Women with pre-pregnancy body mass index (BMI) >25 kg/m² had lower PFUnDA, PFDoDA, and PFTrDA levels than did those with normal BMI (18.5⁻24.9 kg/m²). Pregnant women, who were active smokers (cotinine > 11.49 ng/mL), had higher PFOS than the non-smokers (cotinine < 0.22 ng/mL). Lower levels of PFHxS, PFOS, PFOA, PFNA, and PFDA were observed in women, who had given birth to more than one child. There were also significant positive associations between PFAS levels and annual income or maternal education. PFAS levels varied in women with higher pre-pregnancy BMI, active smoking status, higher education level and annual income. The causes of the individual PFAS differences should be explored in an independent study.

Abstract  Serum samples were collected from volunteers of various ages and both genders using a proportionate stratified sampling method, to assess the exposure of the general population in Busan, South Korea to perfluorinated compounds (PFCs). 16 PFCs were investigated in serum samples from 306 adults (124 males and 182 females) and one day composite diet samples (breakfast, lunch, and dinner) from 20 of the serum donors, to investigate the relationship between food and serum PFC concentrations. Perfluorooctanoic acid and perfluorooctanesulfonic acid were the dominant PFCs in the serum samples, with mean concentrations of 8.4 and 13 ng/mL, respectively. Perfluorotridecanoic acid was the dominant PFC in the composite food samples, ranging from

Abstract  The toxicity of individual perfluoroalkyl acids (PFAAs) has been suggested to be determined by the carbon chain length as well as the functional group attached. We tested seven different PFAAs including both sulfonic and carboxylic PFAAs with different chain length to evaluate the developmental toxicity in zebrafish embryos. Generally, the acute toxicity of PFAAs is relatively low to zebrafish embryos. The EC50 values ranged from 1.5 to 2200mg/L. We observed a relationship between higher toxicity with longer carbon chain. In addition, we also observed a higher toxicity for sulfonic PFAAs than for carboxylic PFAAs.

Abstract  BACKGROUND: Some legacy and emerging environmental contaminants are suspected risk factors for intrauterine growth restriction. However, the evidence is equivocal, in part due to difficulties in disentangling the effects of mixtures. OBJECTIVES: We assessed associations between multiple correlated biomarkers of environmental exposure and birth weight. METHODS: We evaluated a cohort of 1250 term (≥37 weeks' gestation) singleton infants, born to 513 mothers from Greenland, 180 from Poland, and 557 from Ukraine, who were recruited during antenatal care visits in 2002‒2004. Secondary metabolites of diethylhexyl and diisononyl phthalates (DEHP, DiNP), eight perfluoroalkyl acids, and organochlorines (PCB-153 and p,p'-DDE) were quantifiable in 72‒100% of maternal serum samples. We assessed associations between exposures and term birth weight, adjusting for co-exposures and covariates, including pre-pregnancy body mass index. To identify independent associations, we applied the elastic net penalty to linear regression models. RESULTS: Two phthalate metabolites (MEHHP, MOiNP), perfluorooctanoate (PFOA), and p,p'-DDE were most consistently predictive of term birth weight based on elastic net penalty regression. In an adjusted, unpenalized regression model of the four exposures, 2-SD increases in natural log-transformed MEHHP, PFOA, and p,p'-DDE were associated with lower birth weight: -87 g (95% CI: -137, -340 per 1.70 ng/mL), -43 g (95% CI: -108, 23; per 1.18 ng/mL), and -135 g (95% CI: -192, -78 per 1.82 ng/g lipid), respectively; while MOiNP was associated with higher birth weight (46 g; 95% CI: -5, 97 per 2.22 ng/mL). CONCLUSIONS: This study suggests that several of the environmental contaminants, belonging to three chemical classes, may be independently associated with impaired fetal growth. These results warrant follow-up in other cohorts.

Abstract  In 2013 a contamination of drinking water by perfluoroalkylated substances (PFASs) was discovered in areas of the Veneto Region (northern Italy). In this study the exposure to PFASs of people living in the aforesaid areas was characterized: contaminant serum concentrations were measured and compared with those of a control population group living in neighboring areas at background exposure (based on available drinking water data). The enrolled population was also genotyped for the OATP1A2*3 allelic variant, possibly affecting PFAS excretion and hence the internal dose. The difference in PFAS concentrations between exposed and not exposed subjects was significantly larger for nine of the 12 substances analyzed, and confirmed that water contamination had resulted in an appreciable high exposure of the residing population over time. Within the group of exposed subjects, subgroups at different exposure levels were identified. The contamination of drinking water of the residence area was found to be the main factor influencing PFAS serum levels; in addition to water contamination, other relevant influencing factors were sex, the years of residence and raising own livestock. No relationship with the genetic trait for the studied renal transporter was evidenced. These results provide a baseline characterization of PFAS exposure of the monitored population groups for further studies, planned to be carried out in the near future.

Abstract  BACKGROUND: Perfluoroalkyl substances (PFASs) are persistent chemicals with suspected endocrine disrupting abilities applied in consumer products. PFASs have potentially modulating effects on glucose homeostasis. Insulin resistance prevails during third trimester of pregnancy, and this challenge of glucose homeostasis may reveal putative effects of PFAS concentrations on glycemic status.

OBJECTIVE: To investigate associations between five serum PFASs and glucose-related outcomes in pregnant Danish women based on their risk of gestational diabetes mellitus (GDM).

METHODS: In the prospective Odense Child Cohort serum concentrations of five PFASs - perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) - were measured at median gestational week (GW) 11 in pregnant women. An oral glucose tolerance test (OGTT) was performed at GW 28. The statistical analysis was conducted among 158 women with high GDM risk and 160 women with low GDM risk matched by gestational age. Multiple linear regression models were performed to estimate associations between PFAS concentrations and glucose, insulin, C-peptide, homeostatic model of assessment of insulin resistance (HOMA-IR) and beta cell function (HOMA-%β), and insulin sensitivity (Matsuda index) during the 2-h OGTT.

RESULTS: In women with high risk for GDM, a two-fold increase in PFHxS concentration was significantly associated with increased fasting glucose, fasting insulin and HOMA-IR after adjusting for age, parity, educational level and pre-pregnancy BMI. Adjusting for the same confounders, a doubling in PFNA concentration was associated with higher fasting insulin and HOMA-%β. In women with low GDM risk, no associations were found between PFAS concentrations and glucose-related outcomes.

CONCLUSION: PFHxS and PFNA concentrations were associated with impaired glycemic status in metabolically vulnerable pregnant women and might further enhance the risk of developing GDM.

Abstract  Carbon nanotubes@zeolitic imidazole framework-67 (CNTs@ZIF-67), a conductive composite was prepared from carboxylic carbon nanotubes and a cobalt-imidazole framework. It possesses an excellent adsorption capacity (92.12 mg g-1) for the flame retardant tetrabromobisphenol A (TBBPA). The composite was characterized by transmission and scanning electron microscopy, FTIR and X-ray diffractometry. It was then used to modify an acetylene black electrode. Electrochemical studies showed the current response of the modified electrode to be larger than that of electrodes modified with CNTs-COOH or ZIF-67 only. Electrochemical impedance spectroscopy showed this material combination to improve the conductivity of ZIF-67. The addition of perfluorodecanoic acid further improves the response. The sensor is stable, reproducible, and has a linear range of 0.01-1.5 μM TBBPA concentration, with a 4.2 nM detection limit (at S/N = 3). The sensor was successfully applied to the detection of TBBPA in spiked rain and pool water samples. This journal is © The Royal Society of Chemistry.

Abstract  Commercial, untreated cotton fabrics have been directly silver coated using one-step electroless deposition and, subsequently, conformally encapsulated with a thin layer of poly(perfluorodecylacrylate) (PFDA) using initiated chemical vapor deposition (iCVD). The surface of these PFDA encapsulated fabrics are notably water-repellent while still displaying a surface resistance as low as 0.2 Ω cm-1, making them suitable for incorporation into launderable wearable electronics. X-ray photoelectron spectroscopy confirms that the PFDA encapsulation prevents oxidation of the silver coating, whereas unencapsulated samples display detrimental silver oxidation after a month of air exposure. The wash stability of PFDA-encapsulated, silver-coated cotton is evaluated using accelerated laundering conditions, following established AATCC protocols, and the samples are observed to withstand up to twenty home laundering cycles without notable mechanical degradation of the vapor-deposited PFDA encapsulation. As a proof-of-concept, PFDA-Ag cotton is employed as a top and bottom electrode in a layered, all-fabric triboelectric generator that produces voltage outputs as high as 25 V with small touch actions, such as tapping. © 2019 The Royal Society of Chemistry.

Abstract  Concentrations of organohalogenated contaminants (OHCs) can show significant temporal and spatial variation in the environment and wildlife. Most of the variation is due to changes in use and production, but environmental and biological factors may also contribute to the variation. Nestlings of top predators are exposed to maternally transferred OHCs in the egg and through their dietary intake after hatching. The present study investigated spatial and temporal variation of OHCs and the role of age and diet on these variations in plasma of Norwegian white-tailed eagle (Haliaeetus albicilla) nestlings. The nestlings were sampled at two locations, Smøla and Steigen, in 2015 and 2016. The age of the nestlings was recorded (range: 44 - 87 days old) and stable carbon and nitrogen isotopes (δ13C and δ15N) were applied as dietary proxies for carbon source and trophic position, respectively. In total, 14 polychlorinated biphenyls (PCBs, range: 0.82 - 59.05 ng/mL), 7 organochlorinated pesticides (OCPs, range: 0.89 - 52.19 ng/mL), 5 polybrominated diphenyl ethers (PBDEs, range: 0.03 - 2.64 ng/mL) and 8 perfluoroalkyl substances (PFASs, range: 4.58 - 52.94 ng/mL) were quantified in plasma samples from each location and year. The OHC concentrations, age and dietary proxies displayed temporal and spatial variations. The age of the nestlings was indicated as the most important predictor for OHC variation as the models displayed significantly decreasing plasma concentrations of PCBs, OCPs, and PBDEs with increasing age, while concentrations of PFASs were significantly increasing with age. Together with age, the variations in PCB, OCP and PBDE concentrations were also explained by δ13C and indicated decreasing concentrations with a more marine diet. Our findings emphasise age and diet as important factors to consider when investigating variations in plasma OHC concentrations in nestlings.

Abstract  Perfluorocarboxylic acids (PFCAs) are environmental contaminants that are highly persistent, and many are bio-accumulative and have been detected along with their atmospheric precursors far from emission sources. The overall importance of precursor emissions as an indirect source of PFCAs to the environment is uncertain. Previous studies have estimated the atmospheric source of PFCAs using models and degradation pathways of differing complexities, leading to quantitatively different results. We present results from simulations of atmospheric PFCA formation and fate using the chemical transport model GEOS-Chem. We simulate the most up-to-date chemistry available to our knowledge for the degradation of the precursors fluorotelomer alcohol (FTOH), fluorotelomer olefin (FTO), and fluorotelomer iodide (FTI), as well as the deposition and transport of the precursors, intermediates and end-products of the formation chemistry. We calculate yields of C3-C13 PFCAs formed from 4 : 2 to 12 : 2 fluorotelomer precursors and their deposition to the surface. We find that the ratio of long-chain to short-chain PFCAs increases strongly with distance from source regions. We compare our model results to remote deposition measurements and mid-latitude rainwater measurements. The model captures the observed relationship between rainwater abundance and PFCA chain length, as well as the average deposition rates at mid-latitude and Arctic sites, but underestimates the deposition of PFDoA, PFDA, and TFA at mid-latitudes and PFNA at the Devon Ice Cap. We provide estimates of cumulative PFCA deposition globally. We find that given the most recent emission inventory, the atmospheric source of PFCAs is 6-185 tonnes per year globally and 0.1-2.1 tonnes per year to the Arctic.

Abstract  The European Commission asked EFSA for a scientific evaluation on the risks to human health related to the presence of perfluoroalkyl substances (PFASs) in food. Based on several similar effects in animals, toxicokinetics and observed concentrations in human blood, the CONTAM Panel decided to perform the assessment for the sum of four PFASs: PFOA, PFNA, PFHxS and PFOS. These made up half of the lower bound (LB) exposure to those PFASs with available occurrence data, the remaining contribution being primarily from PFASs with short half‐lives. Equal potencies were assumed for the four PFASs included in the assessment. The mean LB exposure in adolescents and adult age groups ranged from 3 to 22, the 95th percentile from 9 to 70 ng/kg body weight (bw) per week. Toddlers and ‘other children’ showed a twofold higher exposure. Upper bound exposure was 4‐ to 49‐fold higher than LB levels, but the latter were considered more reliable. ‘Fish meat’, ‘Fruit and fruit products’ and ‘Eggs and egg products’ contributed most to the exposure. Based on available studies in animals and humans, effects on the immune system were considered the most critical for the risk assessment. From a human study, a lowest BMDL10 of 17.5 ng/mL for the sum of the four PFASs in serum was identified for 1‐year‐old children. Using PBPK modelling, this serum level of 17.5 ng/mL in children was estimated to correspond to long‐term maternal exposure of 0.63 ng/kg bw per day. Since accumulation over time is important, a tolerable weekly intake (TWI) of 4.4 ng/kg bw per week was established. This TWI also protects against other potential adverse effects observed in humans. Based on the estimated LB exposure, but also reported serum levels, the CONTAM Panel concluded that parts of the European population exceed this TWI, which is of concern.

Abstract  There is a general lack of information on the possible effects of perfluoroalkyl substances (PFASs) on thyroid hormones (THs) in wildlife species. The effects of PFASs, which are known endocrine disruptors, on the TH homeostasis in hooded seals (Cystophora cristata) have yet to be investigated. Previously, correlations were found between plasma thyroid hormone (TH) concentrations in hooded seals, and organohalogen contaminants (OHCs) and hydroxyl (OH)-metabolites. Because animals are exposed to multiple contaminants simultaneously in nature, the effects of the complex contaminant mixtures that they accumulate should be assessed. Herein, we analyse relationships between plasma concentrations of multiple contaminants including protein-associated PFASs, hydroxylated metabolites of polychlorinated biphenyls (OH-PCBs) and lipid soluble OHCs and plasma concentrations of free and total THs, i.e. triiodothyronine (FT3, TT3) and thyroxine (FT4, TT4) in hooded seal mothers and their pups. The perfluoroalkyl carboxylates (PFCAs) were the most important predictors for FT3 concentrations and TT3:FT3 ratios in the mothers. The FT3 levels decreased with increasing PFCA levels, while the TT3:FT3 ratios increased. In the pups, hexachlorocyclohexanes (HCHs) were the most important predictors for TT3:FT3 ratios, increasing with increasing HCHs levels. Additionally, perfluoroalkyl sulfonates (PFSAs) and PFCAs were important predictors for FT4:FT3 ratios in hooded seal pups, and the ratio increased with increasing concentrations. The study suggests that PFASs contribute to thyroid disruption in hooded seals exposed to complex contaminant mixtures that include chlorinated and fluorinated organic compounds.

Abstract  Perfluoroalkyl carboxylates (PFCAs) and perfluoroalkyl sulfonates are widespread in human breast milk. However, the occurrence of chlorinated polyfluorinated ether sulfonates (Cl-PFESAs) and fluorotelomer alcohols (FTOHs) in breast milk and their effects on postnatal growth of infants through breast milk consumption are still not well known. This study characterized the occurrence of 16 poly- and perfluoroalkyl substances (PFASs) in breast milk from 174 women in Hangzhou, China and investigated the association between lactation exposure to these PFASs through breast milk consumption and the postnatal growth of infants. Our results showed that perfluorooctanoate (mean 87 pg/mL) was the predominant PFAS in breast milk, followed by perfluorohexanoate (41 pg/mL), 6:2 Cl-PFESA (28 pg/mL), and perfluorooctane sulfonate (25 pg/mL). The occurrence and levels of Cl-PFESAs in Chinese breast milk were firstly reported in the current study. The 8:2 and 10:2 FTOH were detected in half of breast milk samples, with the mean concentration of 9.0 pg/mL and 10 pg/mL, respectively. Breast milk concentrations of C8-C10 PFCAs and 6:2 Cl-PFESA were negatively correlated with infant's length gain rate. Exposed to higher levels of 8:2 FTOH were correlated with decreased infant's weight gain rate. Daily intakes of PFASs via the consumption of breast milk were calculated for infants. Overall, this study firstly demonstrated that lactation exposure to C8-C10 PFCAs, 8:2 FTOH, and 6:2 Cl-PFESA through breast milk consumption may affect the postnatal growth of infants.

Abstract  There is evidence of a positive association between per- and polyfluoroalkyl substances (PFASs) and cholesterol levels in human plasma, which may be due to common reabsorption of PFASs and bile acids (BAs) in the gut. Here we report development and validation of a method that allows simultaneous, quantitative determination of PFASs and BAs in plasma, using 150 μL or 20 μL of sample. The method involves protein precipitation using 96-well plates. The instrumental analysis was performed with ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS), using reverse-phase chromatography, with the ion source operated in negative electrospray mode. The mass spectrometry analysis was carried out using multiple reaction monitoring mode. The method proved to be sensitive, robust, and with sufficient linear range to allow reliable determination of both PFASs and BAs. The method detection limits were between 0.01 and 0.06 ng mL-1 for PFASs and between 0.002 and 0.152 ng mL-1 for BAs, with the exception of glycochenodeoxycholic acid (0.56 ng mL-1). The PFAS measured showed excellent agreement with certified plasma PFAS concentrations in NIST SRM 1957 reference serum. The method was tested on serum samples from 20 healthy individuals. In this proof-of-concept study, we identified significant associations between plasma PFAS and BA levels, which suggests that PFAS may alter the synthesis and/or uptake of BAs. Graphical Abstract.

Abstract  These guidelines revise and replace the U.S. Environmental Protection Agency’s (EPA’s, or the Agency’s) Guidelines for Carcinogen Risk Assessment, published in 51 FR 33992, September 24, 1986 (U.S. EPA, 1986a) and the 1999 interim final guidelines (U.S. EPA, 1999a; see U.S. EPA 2001b). They provide EPA staff with guidance for developing and using risk assessments. They also provide basic information to the public about the Agency's risk assessment methods.

Abstract  Poly- and perfluorinated alkyl substances (PFAS) are environmentally persistent chemicals associated with many adverse health outcomes. The National Toxicology Program evaluated the toxicokinetics (TK) of several PFAS to provide context for toxicologic findings.Plasma TK parameters and tissue (liver, kidney, brain) concentrations are reported for perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA) or perfluorodecanoic acid (PFDA) after single-dose administration in male and female Hsd:Sprague-Dawley® (SD) rats.Generally, longer Tmax and elimination half-lives, and slower clearance f, were correlated with longer chain length. Male rats administered PFOA had a prolonged half-life compared to females (215 h vs. 2.75), while females had faster clearance and smaller plasma area under the curve (AUC). Females administered PFHxA had a shorter half-life (2 h vs. 9) than males and faster clearance with a smaller plasma AUC, although this was less pronounced than PFOA. There was no sex difference in PFDA half-life. Female rats administered PFDA had a higher plasma AUC/dose than males, and a slower clearance. PFDA had the highest levels in the liver of the PFAS evaluated.Profiling the toxicokinetics of these PFAS allows for comparison among subclasses, and more direct translation of rodent toxicity to human populations.

Abstract  We investigated perfluorinated carboxylic acids (PFCAs) with 7-14 carbon atoms (C7-C14) in the Yodo River system in 2013. C7-C11 were detected at most sampling sites. The range and median of total PFCAs (ΣPFCAs) concentrations were 1.0-89.7 and 11.2ngL(-1), respectively. The dominant component was C8 (average for all samples=53.3±8.8%), followed by C7 (19.2±6.7%) and C9 (17.6±7.1%). The levels of C8 were confirmed to decrease greatly over the last 10years. We assessed the fluxes in C7-C11 discharged from the basin based on the concentrations in river water and river flow rate. The flux of discharged ΣPFCAs was 237.0gd(-1) at the most downriver point of the assessment areas. Considering the variability in flow rate due to precipitation, the annual ΣPFCAs flux was estimated to be 86.5-173.4kgy(-1). Identification and quantification of PFCAs sources is difficult because the strength of the sources changes with time, and available information is quite limited. Further monitoring and investigation are necessary to understand sources of PFCAs, as well as their potential for human exposure.

Abstract  The World Trade Center (WTC) disaster released large amounts of various chemical substances into the environment, including perfluoroalkyl substances (PFASs). Yet, no studies have examined exposures in children living or attending schools near the disaster site. We measured serum PFASs in WTC Health Registry (WTCHR) respondents who were ≤8 years of age on September 11, 2001 and a sociodemographically-matched comparison group. We also examined the relationship of PFASs levels with dust cloud exposure; home dust exposure, and with traumatic exposure, the latter to take into account differences related to possible mental health consequences and associated behavioral problems. Serum samples, collected between 2014 and 2016, were analyzed from 123 WTCHR participants and from 185 participants in the comparison group. In the WTCHR group, median perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) levels were 1.81ng/mL and 3.72ng/mL, respectively. Controlling for sex, caloric intake, race/ethnicity, and date of birth, significant increases among WTCHR participants compared with the matched comparison group were detected for perfluorohexanesulfonate (0.23ng/mL increase or 0.24log unit increase, p=0.006); PFOS (0.86ng/mL increase or 0.16log unit increase, p=0.011); PFOA (0.35ng/mL increase or 0.18log unit increase, p<0.001); perfluorononanoic acid (0.12ng/mL increase or 0.17log unit increase, p=0.003); perfluorodecanoic acid (0.06ng/mL increase or 0.42log unit increase, p<0.001); and perfluoroundecanoic acid (0.03ng/mL increase or 0.32log unit increase, p=0.019). Stronger associations were identified for home dust exposures and traumatic exposures than dust cloud. These findings highlight the importance of conducting longitudinal studies in this population to assess possible cardiometabolic and renal consequences related to these exposures.

Abstract  The mechanisms involved in thyroid homeostasis are complex, and perfluoroalkyl substances (PFASs) have been indicated to interfere at several levels in this endocrine system. Disruption of the maternal thyroid homeostasis during early pregnancy is of particular concern, where subclinical changes in maternal thyroid hormones (THs) may affect embryonic and foetal development. The present study investigated associations between THs, thyroid binding proteins (TH-BPs) and PFAS concentrations in pregnant women from Northern Norway. Women participating in The Northern Norway Mother-and-Child contaminant Cohort Study (MISA) donated a blood sample at three visits related to their pregnancy and postpartum period (during the second trimester, 3 days and 6 weeks after delivery) in the period 2007-2009. Participants were assigned to quartiles according to PFAS concentrations during the second trimester and mixed effects linear models were used to investigate potential associations between PFASs and repeated measurements of THs, TH-BPs, thyroxin binding capacity and thyroid peroxidase antibodies (anti-TPOs). Women within the highest perfluorooctane sulfonate (PFOS) quartile had 24% higher mean concentrations of thyroid stimulating hormone (TSH) compared to the first quartile at all sampling points. Women within the highest quartiles of perfluorodecanoate (PFDA) had 4% lower mean concentrations of triiodothyronine (T3) and women within the highest quartile of perfluoroundecanoate (PFUnDA) had 3% lower mean concentrations of free triiodothyronine (FT3). Further, the difference in concentrations and the changes between three time points were the same for the PFAS quartiles. Thyroxin binding capacity was associated with all the THs and TH-BPs, and was selected as a holistic adjustment for individual changes in TH homeostasis during pregnancy. Finally, adjusting for maternal iodine status did not influence the model predictions. Findings in the present study suggest modifications of TH homeostasis by PFASs in a background exposed maternal population. The variation in levels of THs between PFAS quartiles was within normal reference ranges and may not be of clinical significance in the pregnant woman. However, subtle individual changes in maternal THs may have significant consequences for foetal health.

Abstract  Concentrations of 13 perfluoroalkyl substances (PFASs) were quantified in 79 surface soil samples from 17 coastal cities in three provinces and one municipality along the Bohai and Yellow Seas. The ∑PFASs concentrations ranged from less than limitation of quantification (LOQ) to 13.97 ng/g dry weight (dw), with a mean of 0.98 ng/g dw. The highest concentration was observed along the Xiaoqing River from Shandong province, followed by that from the Haihe River in Tianjin (10.62 ng/g dw). Among four regions, ∑PFASs concentrations decreased in the order of Tianjin, Shandong, Liaoning and Hebei, which was consistent with levels of urbanization. Fluorine chemical industries allocated in Shandong and Liaoning played important roles in terms of point emission and contamination of PFASs, dominated by perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Intensive anthropogenic activities involved in urbanization possibly resulted in increasing releases of PFASs from industrial and domestic sources.

Abstract  Perfluoroalkyl and polyfluoroalkyl substances (PFASs), as well as polymers of PFASs, have been widely used in commercial applications and have been detected in humans and the environment. Previous epidemiological studies have shown associations between particular PFAS chemicals and serum lipid concentrations in adults, particularly perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). There exists, however, limited information concerning the effect of PFASs have on serum lipids among children. In the present cross-sectional study, 225 Taiwanese children (12-15 years of age) were recruited to determine the relationship between serum level PFASs and lipid concentration. Results showed that eight out of ten particular PFASs were detected in the serum of >94% of the participants. Serum PFOS and perfluorotetradecanoic acid (PFTA) levels were at an order of magnitude higher than the other PFASs, with arithmetical means of 32.4 and 30.7 ng/ml in boys and 34.2 and 27.4 ng/ml in girls, respectively. However, the variation in serum PFTA concentration was quite large. Following covariate adjustment, linear regression models revealed that PFOS, PFOA, and perfluorononanoic acid (PFNA) were positively associated with total cholesterol (TC), low-density lipoprotein (LDL) and triglycerides (TG), particularly for PFOS and PFTA. Quartile analysis, with the lowest exposure quartile as a reference, yielded associations between serum PFTA and elevations in TC (p=0.002) and LDL (p=0.004). Though not statistically significant, high-density lipoprotein (HDL) appeared to decrease linearly across quartiles for PFOS and PFOA exposure. In conclusion, a significant association was observed between serum PFASs and lipid level in Taiwanese children. These findings for PFTA are novel, and emphasize the need to investigate the exposure route and toxicological evidence of PFASs beyond PFOS and PFOA.

Abstract  This study investigates perfluoroalkyl carboxylic acids (PFCAs) contamination of edible fish muscle from Japanese coastal waters. The concentrations of PFCAs with 8-14 carbon atoms (C8-C14) in Pacific cods in Hokkaido, Japan were 51 (median: pg/g-wet weight) for C8, 93 for C9, 99 for C10, 746 for C11, 416 for C12, 404 for C13, and 93 for C14. The levels of C9-C14 PFCAs in fish were strongly correlated to each other, but not to C8 and the other chlorinated persistent organic pollutants, indicating that C9-C14 PFCAs have a different emission source and/or bioaccumulation mechanism. The relative ratios between estimated PFCAs intake through fish consumption and the reported total dietary exposure of PFCAs were less than 1 for C8 to C9, but were more than 1 for C10 to C14. This result strongly suggests that fish consumption is a significant source of human dietary exposure to C10-C14 PFCAs.

Abstract  Perfluorinated alkylated substances (PFASs) have been measured in liver samples from terrestrial organisms from Greenland and the Faeroe Islands. Samples from ptarmigan (West Greenland), reindeer (southwest-Greenland), muskox (East Greenland), and land-locked Arctic char from southwest Greenland and the Faroe Islands were analyzed. In addition, PFASs levels in land-locked brown trout from Faroese lakes are reported. Of the 17 PFASs analyzed in the samples the following compounds were detected: PFOS, PFNA, PFDA, PFUnA, PFDoA, PFTrA, and PFTeA. PFNA was the compound detected in most samples and in all species. However, the compound detected at highest concentration was dependent on species, with overall highest concentrations of PFTrA and PFUnA being detected in trout liver from Lake á Mýranar (Faroe Islands). In muskox, the PFAS occurring at highest concentrations was PFDA, which was among the PFAS detected at lowest concentrations in freshwater fish, and was only detected in one individual ptarmigan. The concentration of PFOS, PFDoA and PFTrA in Arctic char from Greenland and Faroe Islands were similar, whereas the concentration of PFNA, PFDA and PFUnA were higher in Arctic char than those from Greenland. The opposite was observed for PFTeA. The PFASs occurring at highest concentrations in trout were PFTrA and PFUnA. Arctic char from Lake á Mýranar had much lower concentrations of PFTrA and PFUnA than in trout from the lakes analyzed, but a higher concentration of PFTeA than trout from the same lake. A clear pattern with odd-carbon number homologues concentrations higher than the next lower even homologue was observed in fish samples, which is consistent with the hypothesis of transport of volatile precursors to remote regions.

Abstract  The authors investigated the individual effects of Ca(2+) and Na(+) on the bioaccumulation of 6 types of perfluoroalkyl substances (PFASs), including perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), and perfluorododecanoic acid (PFDoA), by Daphnia magna in water with 10 mg L(-1) bovine albumin or soy peptone. The bioaccumulation factors of PFASs by D. magna decreased linearly with the increase of Ca(2+) and Na(+) concentrations. The inhibition effect of Ca(2+) was stronger than that of Na(+), and the decreasing percentages of the body burden of PFASs in D. magna caused by the increment of 1 mmol L(-1) Ca(2+) and 1 mmol L(-1) Na(+) were 41% to approximately 48% and 2% to approximately 5%, respectively, in the presence of soy peptone. The partition coefficients (Kp) of PFASs between protein and water increased with rising Ca(2+) and Na(+) concentrations. The elevated Kp values led to the reduced concentrations of freely dissolved PFASs. This resulted in a decrease of PFAS bioaccumulation in D. magna, and the body burden of each PFAS was positively correlated with its freely dissolved concentration in water. The present study suggests that cations should be considered in the assessment of bioavailability and risk of PFASs in natural waters containing proteinaceous compounds.

Abstract  The influence of humic substances and protein compounds on the bioaccumulation of six types of perfluoroalkyl substances (PFASs) in Daphnia magna was compared. The humic substances included humic acid (HA) and fulvic acid (FA), the protein compounds included chicken egg albumin (albumin) and peptone, and the PFASs included perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid, perfluoroundecanoic acid, and perfluorododecanoic acid. Four concentrations (0, 1, 10, and 20 mg L(-1)) of the four dissolved organic matter (DOM) types were investigated. At the 1 mg L(-1) level, HA and albumin enhanced all tested PFAS bioaccumulation, whereas FA and peptone only enhanced the bioaccumulation of shorter-chain PFASs (PFOS, PFOA, and PFNA). However, all four DOM types decreased all tested PFAS bioaccumulation at the 20 mg L(-1) level, and the decreasing ratios of bioaccumulation factors caused by FA, HA, albumin, and peptone were 1-49%, 23-77%, 17-58%, and 8-56%, respectively compared with those without DOM. This is because DOM not only reduced the bioavailable concentrations and uptake rates of PFASs but also lowered the elimination rates of PFASs in D. magna, and these opposite effects would change with different DOM types and concentrations. Although the partition coefficients (L kg(-1)) of PFASs between HA and water (10(4.21)-10(4.98)) were much lower than those between albumin and water (10(4.92)-10(5.86)), their effects on PFAS bioaccumulation were comparable. This study suggests that although PFASs are a type of proteinophilic compounds, humic substances also have important effects on their bioavailability and bioaccumulation in aquatic organisms.