Article

Perfluoroalkyl Compounds (PFCs) in Indoor Dust: Concentrations, Human Exposure Estimates, and Sources

Article

Perfluoroalkyl Compounds (PFCs) in Indoor Dust: Concentrations, Human Exposure Estimates, and Sources

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Abstract

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are globally distributed, persistent, toxic, and are found in human blood and serum. Exposure pathways are not well characterized. To better understand indoor dust ingestion as a potential pathway for human exposure, we determined the concentrations of these compounds in dust collected from 10 houses, 38 apartments, 10 day care centers, 10 offices, and 5 cars. Samples were prepared using a rapid extraction and cleanup method and analyzed using LC-MS/MS. PFOS and PFOA were found in dust samples from all microenvironments and their concentrations were significantly positively correlated to each other. Highest median concentrations were seen in offices (PFOS: 110 ng/g dry weight) and apartments (PFOA: 93 ng/g dw). Adult and toddler dust ingestion exposures were estimated and compared to dietary exposure data from Canada and Spain. Results show that diet is the most important exposure route, but in a worst case scenario, dust ingestion may also be significant.

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... Consumer products can transfer both short-and longchain PFAS to dust either through the air or directly from the product itself, although the actual mechanism of transfer is unknown [14,15]. Given that individuals spend over 90% of their day inside on average, the indoor environment is a significant route of exposure to airborne PFAS and to PFASladen dust [11,16]. Infants and young children are especially susceptible to chemical exposures through settled dust, given the extended periods that they spend on or near the floor coupled with their high hand-to-mouth activity [17,18]. ...
... Higher levels of various PFAS in dust have been observed in homes, childcare facilities, and workplaces with carpeting as compared to indoor spaces with other flooring materials such as waxed wood, laminate, vinyl tiling, and linoleum [16,49,50,[62][63][64][65]. For example, findings from settled dust collected from childcare facilities and offices have demonstrated increased 6:2 FTOH, 8:2 FTOH, and 10:2 FTOH concentrations in spaces with carpeting compared to other flooring materials [49,53,66]. ...
... Paper Products Elevated concentrations of PFCAs (PFOA, PFHxA) and PFSAs (PFOS) have been detected in settled dust collected from offices in Belgium and Sweden [16,98]. High-volume paper product use or paper manufacturing processes (i.e., newspaper and book publishers) have been suggested to contribute to increased exposure to PFOS and PFOA [16]; these compounds are known to be in inks, applied paper and cardboard, and found in the transfer belts of copiers and printers [16,99,100]. ...
Article
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Purpose of Review Per- and polyfuoroalkyl substances (PFAS) are a family of more than 7,000 fuorinated compounds. The carbon-fuorine bond of PFAS provides desirable hydrophobic and oleophobic properties and stability that has led to widespread usage in consumer products and industrial applications. The strength of the carbon-fuorine bond also prevents appreciable degradation once released into the environment. Consequently, various household products can release volatile and nonvolatile PFAS into the indoor environment that often concentrate in dust. We discuss the diversity of PFAS in settled dust, emission sources of these chemicals, changes in PFAS profles in dust over the past century, and the implications for human health. Recent Findings Sources of PFAS found in dust include building materials and furnishings and consumer products used in typical indoor spaces. Daycares and workplaces are emphasized as locations with widespread exposure due to the presence of treated carpeting and industrial-strength cleaners. Comparison and interpretation of fndings across studies are complicated by the diferent ways in which PFAS are screened across studies. We further discuss recent developments in non-targeted software for the comprehensive annotation of PFAS in indoor dust and emphasize the need for comprehensive and harmonized analytical workfows. Summary We highlight the detection and diversity of PFAS in settled dust collected from various indoor spaces, including locations with vulnerable subpopulations. There are opportunities for future research to leverage settled dust as a sentinel environmental matrix to evaluate the link between inhalation and ingestion routes of PFAS exposure to adverse health.
... Dust is likely to represent a more important exposure pathway for children than adults due to children's higher exposure factors related to their body weights, such as hand-to-mouth frequency, object-to-mouth frequency and dust ingestion rate, but even because of their proximity to the floor while crawling and playing on the floor and thereby stirring up dust (US EPA, 2011;Winkens et al., 2017b;Wu et al., 2018). The reported estimated daily intakes (EDIs) for PFASs via dust ingestion in the literature reflect this, as they are higher for toddlers or children than for adults (Björklund et al., 2009;Ericson Jogsten et al., 2012;Shoeib et al., 2005;Tian et al., 2016;Zhang et al., 2010). ...
... There are many studies that have measured PFASs in sieved and settled dust of various indoor environments, including cars, offices, homes and day care centres (Björklund et al., 2009;D'Hollander et al., 2010;Eriksson and Kärrman, 2015;Goosey and Harrad, 2011;Haug et al., 2011;Karásková et al., 2016;Shoeib et al., 2011). In our study, we present a recent dataset for a large number of floor dust samples (n = 65) and for a long list of PFAS analytes (n = 62). ...
... Two subsequent fast extractions were used for the volatile GCfraction and non-volatile LC-fraction, respectively, which were based on a combination of two different previously published methods (Björklund et al., 2009;Bohlin-Nizzetto et al., 2015). Prior to extraction, the samples were spiked with mass labelled (ML) internal standards (50 μL of 10 pg/μL ML-PFCAs, PFSAs, PAPs and FOSAs and FO-SAAs (see Table S1); 50 μL of a mixture with 375 pg/μL (ML-Et/ MeFOSE) and 125 pg/μL (ML-Et/MeFOSA) as well as 90 μL of 300 pg/ μL of a ML-FTOH mixture, list with acronyms see Table S1). ...
Article
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We analysed floor dust samples from 65 children's bedrooms in Finland collected in 2014/2015 for 62 different per- and polyfluoroalkyl substances (PFASs) with a simple and highly efficient method. Validation results from the analysis of standard reference material (SRM) 2585 were in good agreement with literature data, while 24 PFASs were quantified for the first time. In the dust samples from children's bedrooms, five perfluoroalkyl carboxylic acids (PFCAs) and perfluorooctane sulfonic acid (PFOS) were detected in more than half of the samples with the highest median concentration of 5.26 ng/g for perfluorooctanoic acid (PFOA). However, the dust samples were dominated by polyfluoroalkyl phosphoric acid esters (PAPs) and fluorotelomer alcohols (FTOHs) (highest medians: 53.9 ng/g for 6:2 diPAP and 45.7 ng/g for 8:2 FTOH). Several significant and strong correlations (up to ρ = 0.95) were found among different PFASs in dust as well as between PFASs in dust and air samples (previously published) from the same rooms. The logarithm of dust to air concentrations (log Kdust/air) plotted against the logarithm of the octanol-air partition coefficient (log Koa) resulted in a significant linear regression line with R2 > 0.88. Higher dust levels of PFOS were detected in rooms with plastic flooring material in comparison to wood (p < 0.05). Total estimated daily intakes via dust (EDIdust) and air (EDIair) of perfluoroalkyl acids (PFAA), including biotransformation of precursors to PFAAs, were calculated for 10.5-year-old children. The total EDIdust for PFOA and PFOS were estimated to be 0.007 ng/kg bw/day and 0.006 ng/kg bw/day, respectively, in an intermediate exposure scenario. The sum of the total EDIs for all PFAAs was slightly higher for dust than air (0.027 and 0.019 ng/kg bw/day). Precursor biotransformation was generally important for total PFOS intake, while for the PFCAs, FTOH biotransformation was estimated to be important for air, but not for dust exposure.
... Strong positive correlations were obtained between PFOS and PFOA (r s = 0.705, p b 0.01; Table S4) and these with PFHxS (r s N 0.438, p b 0.05). First paper reporting data for PFOA and PFOS in house dust (Moriwaki et al., 2003) also found a positive correlation between them, result that was also observed for dust from elevate surfaces (Björklund et al., 2009;Haug et al., 2011) and settle dust collected with specific protocols (D'Hollander et al., 2010;Fraser et al., 2013;Goosey and Harrad, 2011) or vacuum cleaner bags (Knobeloch et al., 2012;Kubwabo et al., 2005;Shoeib et al., 2011Shoeib et al., , 2016Strynar and Lindstrom, 2008;Xu et al., 2013). Positive correlation found between PFOA, PFOS and PFHxS levels and the amount of carpeting in homes have been associated to the use of carpet surface treatment products (Kubwabo et al., 2005;Shoeib et al., 2011). ...
... Dust collected from flats exhibited higher PFHxS, PFTeDA, PFHxDA and PFODA concentrations than detached houses. A similar result was reported by Björklund et al., 2009for PFOS and PFOA in dust collected during 2006/2007 in Stockholm city (Sweden), but in this case, sampling was done in surfaces at least one meter above the floor. ...
... However, assuming that i) present study has evaluated settle dust and ii) studies conducted by Winkens et al., 2017 concluded that reliable methods to calculate dermal uptakes are not available, human exposure assessment was performed considering only dust intake via oral ingestion. Thus, Estimated Daily Intakes (EDI dust ingestion ; ng/day) were calculated multiplying PFAS concentrations C dust , ng/g), dust ingestion rates (IR dust , mg/day), and the gastrointestinal absorption fraction (AF, 0.94; mean value obtained from Björklund et al., 2009;Egeghy and Lorber, 2011;Ericson Jogsten et al., 2012;Goosey and Harrad, 2011;Liu et al., 2011;Shoeib et al., 2005Shoeib et al., , 2011Shoeib et al., , 2016Tian et al., 2016;Xu et al., 2013), as it is shown in Eq. (1). EDI values were calculated for toddlers (7 months to 4 years; U.S. EPA, 2017) and adults (20 to 59 years) at median and worst-case scenarios. ...
Article
65 house dust samples from three European countries (Belgium, Italy and Spain) were evaluated for the presence of 20 polyflouroalkyl substances (PFASs) including perfluoroalkane sulfonic acids (PFSAs), perfluoroalkyl carboxylic acid (PFCAs) and perfluoroalkane sulfonamides (PFOSAs). The three countries presented similar PFAS levels ranging from 3.13 to 155 ng/g (12.9 ng/g; median), but in all cases PFCAs concentrations (6.92, 15.2 and 8.68 ng/g; median for Belgium, Italy and Spain) were higher than those obtained for PFSAs (2.30, 1.76 and 2.68 ng/g). Interestingly, in comparison to previously published data exhibited an increase in perfluorobutanesulfonate (PFBS) concentrations in Belgian house dust. On the other hand, levels of perfluorooctanesulfonate (PFOS) decreased in Spanish case. Data were examined for relationships between PFAS house dust levels, building and outdoor surrounding characteristics and occupant habits. Main findings revealed a positive association between PFOS concentrations and the building edification age, which could highlight a decrease in the use of this chemical in Europe. Similarly, perfluorohexanesulfonate (PFHxS) levels correlated with the percentage of the floor covered by textiles. Homes located in industrial sites showed higher PFCA levels compared to urban or agricultural locations, revealing the industrial processes as a potential source of these chemicals in Europe. Data obtained were used to perform human exposure assessment for dust intake via oral ingestion. Estimated daily intakes, calculated for toddlers and adults at median and worst case scenarios, were below oral Reference Dose (RfD) and tolerable daily intakes (TDI). However, in perfluorooctanoic acid (PFOA) case, dust ingestion significance to total dietary exposure reached values of 51% for toddlers in the worst case scenario.
... Only a few studies measured indoor dust from children' bedrooms and schools (Strynar and Lindstrom, 2008;Bjorklund et al., 2009;Goosey and Harrad, 2011;California Environmental Protection Agency, 2012;Winkens et al., 2018;Giovanoulis et al., 2019). To our knowledge, only two of those focused on PFASs in dust from U.S. childcare centers. ...
... Non-detect values were replaced by MDL/sqrt (2) for median calculations but not for the range. Results for individual samples are presented in Table S6 (Strynar and Lindstrom, 2008;Bjorklund et al., 2009;Goosey and Harrad, 2011), probably because samples were collected 10e20 years ago. Additionally, compared to carpet dust samples from California childcare centers from 2010 to 2011 (California Environmental Protection Agency, 2012), we found higher concentrations for C 4 eC 6 PFAAs, but lower or comparable concentrations for C 8 eC 10 PFAAs, indicative of a market shift from long-chain to short-chain PFASs in the last decade. ...
Article
Carpets can be a significant source of per- and polyfluoroalkyl substances (PFASs) in the indoor environment and may be an especially important source of exposure for children and toddlers. Most previous studies focused on measuring indoor dust only. In this study, we measured PFAS concentrations in paired carpet and dust samples from 18 California childcare centers in 2018 to investigate carpet as a contributor to PFASs in dust. Median total PFAS concentrations (∑PFASs) in carpets and dust were 471 ng/g and 523 ng/g, respectively. 6:2 FTOH and 6:2 FTSA were the two dominant PFASs, collectively accounting for over 50% of the ∑PFASs in both media. Other frequently detected PFASs included C4–C14 perfluoroalkylcarboxylic acids, C4–C8 perfluoroalkylsulfonic acids, PFDS, 4:2 FTSA, 8:2 FTSA, FOSA, MeFOSE, EtFOSE, 8:2 FTOH, and 10:2 FTOH. We found strong associations between PFAS levels in carpet and dust pairs, suggesting that carpets can be a source and a sink for PFASs. The estimated total perfluoroalkyl acids (PFAA) intake via dust ingestion for children was 0.023, 0.096, and 1.9 ng/kg body weight/day in the low-, intermediate-, and high-exposure scenarios, respectively. Our data suggest that PFASs of emerging concern are playing an increasingly important role in indoor exposure to PFASs.
... PFOA and PFOS, the most common PFAS reported in all environmental compartments were also detected most frequently in dust samples in this study. The level of PFOA in this study (median 7.7 ng/g; max 36 ng/g) was in similar range with a previous measurement in the dust of 39 child care facilities in USA (median 8 ng/g; max 235 ng/g) (Bradman et al., 2012), while it was five times lower compared with another study from 10 Swedish daycare centers (median 41 ng/g; max 110 ng/g) (Bjorklund et al., 2009) and much lower than 102 homes and 10 day care centers (median 142 ng/g; max 1960 ng/g) in USA (Strynar and Lindstrom, 2008). For PFOS, the result in this study (median 12 ng/ g; max 49 ng/g) was slightly higher than in US child care centers (median 6.2 ng/g; max 67 ng/g) but lower than in dust from Swedish daycare centers (median 31 ng/g; max 65 ng/g) (Bjorklund et al., 2009;Bradman et al., 2012) and US homes and day care centers (median 201 ng/g; max 12,100 ng/g) (Strynar and Lindstrom, 2008). ...
... The level of PFOA in this study (median 7.7 ng/g; max 36 ng/g) was in similar range with a previous measurement in the dust of 39 child care facilities in USA (median 8 ng/g; max 235 ng/g) (Bradman et al., 2012), while it was five times lower compared with another study from 10 Swedish daycare centers (median 41 ng/g; max 110 ng/g) (Bjorklund et al., 2009) and much lower than 102 homes and 10 day care centers (median 142 ng/g; max 1960 ng/g) in USA (Strynar and Lindstrom, 2008). For PFOS, the result in this study (median 12 ng/ g; max 49 ng/g) was slightly higher than in US child care centers (median 6.2 ng/g; max 67 ng/g) but lower than in dust from Swedish daycare centers (median 31 ng/g; max 65 ng/g) (Bjorklund et al., 2009;Bradman et al., 2012) and US homes and day care centers (median 201 ng/g; max 12,100 ng/g) (Strynar and Lindstrom, 2008). In a previous study by Goosey and Harrad (2011), where dust from daycare centers and classrooms was collected in UK during 2007-2008, the PFOA level (median 240 ng/g; max 1700 ng/g) and PFOS (median 840 ng/g, max 3700 ng/g) levels were 31 and 69 times higher respectively than the determined levels in this current study. ...
Article
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Consumer goods and building materials present in the preschool environment can be important sources of hazardous chemicals, such as plasticizers, bisphenols, organophosphorus and brominated flame retardants, poly- and perfluoroalkyl substances, which may pose a health risk to children. Even though exposure occurs via many different pathways, such as food intake, inhalation, dermal exposure, mouthing of toys etc., dust has been identified as a valuable indicator for indoor exposure. In the present study, we evaluate the efficiency of product substitution actions taken in 20 Swedish preschools from the Stockholm area to reduce the presence of hazardous substances in indoor environments. Dust samples were collected from elevated surfaces in rooms where children have their everyday activities, and the concentrations found were compared to the levels from a previous study conducted in 2015 at the same preschools. It was possible to lower levels of hazardous substances in dust, but their continued presence in the everyday environment of children was confirmed since bisphenol A, restricted phthalates and organophosphate esters were still detectable in all preschools. Also, an increase in the levels of some of the substitutes for the nowadays restricted substances was noted; some of the alternative plasticizers to phthalates, such as DEHA and DEHT, were found with increased concentrations. DINP was the dominant plasticizer in preschool dust with a median concentration of 389 μg/g, while its level was significantly (p = 0.012) higher at 716 μg/g in preschools with polyvinyl chloride (PVC) flooring. PBDEs were now less frequently detected in dust and their levels decreased 20% to 30%. This was one of the few times that PFAS were analyzed in preschool dust, where 6:2 diPAP was found to be most abundant with a median concentration of 1140 ng/g, followed by 6:2 PAP 151 ng/g, 8:2 diPAP 36 ng/g, N-Et-FOSAA 18 ng/g, PFOS 12 ng/g, PFOA 7.7 ng/g and PFNA 1.1 ng/g. In addition, fluorotelomer alcohols were detected in 65–90% of the samples. Children's exposure via dust ingestion was evaluated using intermediate and high daily intake rates of the targeted chemicals and established health limit values. In each case, the hazard quotients (HQs) were < 1, and the risk for children to have adverse health effects from the hazardous chemicals analyzed in this study via dust ingestion was even lower after the product substitution actions were taken in preschools.
... Daily intake (pg/kg bw) of PFASs in children and adults following a median and worst exposure to dust by hand to mouth behaviour and inhalation. Å. Gustafsson et al. other studies from Sweden reporting levels 18-142 ng/g (Eriksson and Kärrman, 2015;Björklund et al., 2009). For PFOS, this study reported lower concentrations (7.4 ng/g) compared to dust sampled from houses (49 ng/g dust) and from apartments (175 ng/g dust) in Sweden (Björklund et al., 2009), but similar compared to house dust sampled in 2013-2014 in Sweden, with PFOS concentrations of 4 ng/g dust (Eriksson and Kärrman, 2015). ...
... Å. Gustafsson et al. other studies from Sweden reporting levels 18-142 ng/g (Eriksson and Kärrman, 2015;Björklund et al., 2009). For PFOS, this study reported lower concentrations (7.4 ng/g) compared to dust sampled from houses (49 ng/g dust) and from apartments (175 ng/g dust) in Sweden (Björklund et al., 2009), but similar compared to house dust sampled in 2013-2014 in Sweden, with PFOS concentrations of 4 ng/g dust (Eriksson and Kärrman, 2015). Eriksson and Kärrman also detected PFAS on dust from countries from four continents; Australia, Asia, Canada, and Europe (Table S5). ...
Article
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Indoor environmental pollutants are a threat to human health. In the current study, we analysed 25 per- and polyfluoroalkyl substances (PFASs) in seven different size fraction of house dust including the two relevant for exposure via ingestion and inhalation. The highest PFAS concentration is found in the inhalable particulate fraction which is explained by the increased surface area as the particulate's sizes decrease. The estimated daily intake (EDI) of the individual PFAS and exposure pathways were calculated for children and adults. In addition, the total EDI for PFOA and its precursors was estimated. The polyfluoroalkyl phosphoric acid diesters (diPAP), followed by PFOA and PFHxAfluortelomer, showed the highest concentrations of PFAS analysed. The cumulative EDI of PFAS for children was 3.0 ng/kg bw per day, a worst-case scenario, which is 17 times higher than the calculated EDI for adults. For children, ingestion of dust was found to result in 800 times higher PFOA exposure than via inhalation. The contribution from PFOA precursors corresponded to only 1% of the EDI from dust indicating PFOA as the main source of exposure. The EDI's of PFOA and PFOS from dust were lower than the calculated EDI's from food ingestion reported by the Swedish Food Agency. Our data indicate that the EDI for the sum of four PFASs: PFOA, PFNA, PFHxS and PFOS from dust intake alone is close to the established tolerable weakly intake of 4.4 ng/kg bw in children, set by European Food Safety Authority (EFSA) in 2020. The combined EDI levels PFOA and PFOS from both dust and food exceeded the EFSA TWI for both children and adults. This study demonstrates that dust is a relevant exposure pathway for PFAS intake and that analysis of relevant particle size fractions is important for evaluation of dust as an exposure pathway.
... The extreme environmental persistence, toxic and bioaccumulative properties of PFAS have resulted in concerns over their environmental fate and prevalence, hence several studies have established different pathways of human exposure to PFAS. These include the ingestion of house dust [4][5][6], consumption of food and water [3,[7][8][9][10][11][12][13], and air inhalation [5,6], among others, with diet being the major exposure pathway for nonoccupationally exposed populations [8,[10][11][12]. ...
... Two volatile organic modifiers (ammonium formate and ammonium acetate) at different concentrations were optimized for the separation of PFAS. We found 10 mM of ammonium acetate suitable for the complete resolution of all target analytes with improved sensitivity, though concentrations ranging from 1-5 mM of ammonium acetate as mobile phase modifier are mostly reported in the literature for the chromatographic separation of PFAS [3,4,36]. The improved chromatographic peak shape, selectivity and higher signal to noise ratio obtained is attributed to the well-known advantages of high pH mobile phases in negative electrospray ionization MS [37]. ...
Article
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An ultra-high performance liquid chromatography tandem mass spectrometry method was developed and validated for the sensitive determination and unambiguous confirmation of residues of per and polyfluorinated alkyl substances (PFAS) in breastmilk, retail milk and infant formulas following two sample preparation methods. Sample pre-treatment was carried out by a simplified QuEChERS method without requiring dSPE or any further clean-up. The method was validated in accordance with the requirements of Commission Decision 657/2002/EC with slight modifications. The method displayed good linearity with R2 ranging from 0.9843–0.9998 for all target PFAS. The recovery and within-laboratory reproducibility of the method (n = 63) were in the range 60–121% and 5–28%, respectively. The decision limit, detection capability and limit of quantitation ranged from 30–60 ng kg−1 to 40–100 ng kg−1 and 5–50 ng kg−1, respectively. Acceptable matrix effect values in the range −45–29% were obtained with uncertainty of measurement lower than 25% for all target PFAS. The method displays its suitability for the sensitive and high-throughput confirmatory analysis of C4–C14 PFAS in breastmilk, dairy milk and infant formulas.
... As negligible differences are observed for all the other compounds, both chromatographic methods can be used for detecting OPE. Table 4 shows PFAS results studied here (ng/g), compared to both NIST concentrations in the certificate of analysis and data found in the literature (Björklund et al. 2009;Reiner et al. 2015;Winkens et al. 2018;Giovanoulis et al. 2019;Hall et al. 2020;Harrad et al. 2020;Kassotis et al. 2021;Padilla-Sánchez and Haug 2016). Literature data are reported as the average of the n values found for each compound (last column in Table 4). ...
... Data are expressed as mean value ± uncertainty computed at the 95% level of confidence. Björklund et al. 2009;Reiner et al. 2015;Winkens et al. 2018;Giovanoulis et al. 2019;Hall et al. 2020;Harrad et al. 2020;Kassotis et al. 2021 The disassembly site showed a high concentration of OPEs in the settled dust, mainly due to TPhP, TBEP, and TDCPP. OPE high concentrations are expected because all the collected dust originated from the manual fractionation of end-of-life personal computers, printers, scanners, display devices, small household appliances, telecommunication equipment, cellular phones, and electronic systems. ...
Article
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An analytical method for detecting flame retardants was slightly modified and optimized for the simultaneous determination of 11 organophosphate esters (OPEs) and 26 polyfluoralkyl substances (PFASs) contained in dust. All the analytes were determined in HPLC/MS–MS, and OPEs were also analyzed in GC/MS, and the results were compared. The study was conducted through the investigation of the Standard Reference Material SRM 2585 of the National Institute of Standard and Technology (NIST). The results were compared with the available reference mass fraction reported in the NIST certificate. The mass fraction obtained for the other OPEs and PFASs was compared to available data in the literature. After verifying the reliability of the results, the method was applied to environmental samples of settled dust, collected in four workplaces, where OPE and PFAS content is expected to be higher than in house dust: a mechanical workshop, an electronic repair center, a disassembly site, and a shredding site of two electronic waste recycling plants. By analyzing both PFASs and OPEs in the same samples, the present work demonstrated that the selected working places were more polluted in OPEs than houses; on the contrary, PFAS content in house dust proved to be more than ten times higher than that in workplaces. Additional research is necessary to confirm these data. Nevertheless, because this preliminary study showed not negligible concentrations of OPEs in some workplaces and of PFASs in houses, their monitoring should be extended to other domestic and selected working sites.
... Children aged 6 months to 3 years place their hands and objects into their mouths several times a day [3,4], substantially increasing their potential chemical exposure through the non-dietary ingestion route [1][2][3]. Chemicals from personal care products (PCPs), household products (e.g., cleaners, pesticides), electronic appliances, furniture, and building materials can be released from their original sources and partition into dust [5,6], making it an important exposure medium for children. ...
... Previous targeted analysis studies have reported measurements for a plethora of organic and inorganic substances in dust. Some examples are polybrominated diphenyl ethers (PBDEs) [6], per-and polyfluoroalkyl substances (PFAS) [5], several pesticides [13], chemicals from PCPs [14], and heavy metals [15]. Recently published non-targeted analysis (NTA) studies have indicated that house dust contains thousands of chemicals of varying structures and properties [16,17]. ...
Article
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Chemical exposure via dust ingestion is of great interest to researchers and regulators because children are exposed to dust through their daily activities, and as a result, to the many chemicals contained within dust. Our goal was to develop a workflow to identify and rank organic chemicals that could be used as tracers to calculate children’s dust ingestion rates. We proposed a set of criteria for a chemical to be considered a promising tracer. The best tracers must be (1) ubiquitous in dust, (2) unique to dust, (3) detectable as biomarkers in accessible biological samples, and (4) have available or obtainable ADME information for biomarker-based exposure reconstruction. To identify compounds meeting these four criteria, we developed a workflow that encompasses non-targeted analysis approaches, literature and database searching, and multimedia modeling. We then implemented an ad hoc grading system and ranked candidate chemicals based on fulfillment of our criteria (using one small, publicly available dataset to show proof of concept). Initially, five chemicals (1,3-diphenylguanidine, leucine, piperine, 6:2/8:2 fluorotelomer phosphate diester, 6:2 fluorotelomer phosphate diester) appeared to satisfy many of our criteria. However, a rigorous manual investigation raised many questions about the applicability of these chemicals as tracers. Based on the results of this initial pilot study, no individual compounds can be unequivocally considered suitable tracers for calculating dust ingestion rates. Future work must therefore consider larger datasets, generated from broader measurement studies and literature searches, as well as refinements to selection criteria, to identify robust and defensible tracer compounds.
... The lack of water infrastructure causes people to spend less time on other income-generating activities (Blackden & Wodon, 2006;Harvey & Taylor, 2000). Björklund, Thuresson, and De Wit (2009) claimed that in the case of the existence of water infrastructures, people may do better economic activities (Jenkins & Sugden, 2006) and as a result, the context of economic development is created (Meeks, 2017). ...
Article
One of the main subjects, governments have been facing is fair distribution of income, and making effort to improve it. In this study, we evaluated the effects of economic (energy, water, ICT) and social (health, education) infrastructure expenses on income inequality in the Iranian provinces for the period of 2007-2016 by the panel corrected standard errors (PCSE) model. The results show that social and economic infrastructures improvements reduce income inequality. However, the magnitude of these effects varies. Investment on education, healthcare, communication technology, energy, and water infrastructures has the greatest impact on income inequality reduction, respectively. Therefore, in order to reduce inequality in deprived areas, combination and optimal allocation of economic and social infrastructures should be considered.
... The most prominent PFAS are perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). Both substances have been identified in dust, soil and ground water (Björklund et al., 2009;Murakami et al., 2009;Stahl et al., 2009;Zareitalabad et al., 2013) as well as in human blood serum, lung, liver and breast milk (Apelberg et al., 2007;Maestri et al., 2006;Olsen et al., 2003;Völkel et al., 2008). After resorption into the blood stream, PFAS bind to serum albumin which leads, along with slow elimination rates, to high serum half-lifes in the human body, e.g. ...
Article
Perfluoralkylated substances (PFAS) such as perfluorooctanoic acid (PFOA) or perfluorooctanesulfonic acid (PFOS) are used to produce, e.g., surface coatings with water- and dirt-repellent properties. These substances have been shown to be hepatotoxic in rodents, and the mechanism of action is mostly attributed to the PFAS-mediated activation of the peroxisome proliferator-activated receptor alpha (PPARα). In the present study, we investigated by using luciferase-based reporter gene assays whether PFOA, PFOS and six alternative PFAS can activate, in addition to PPARα, eight other human nuclear receptors. All tested PFAS except for perfluorobutanesulfonic acid (PFBS) were able to activate human PPARα. Perfluoro-2-methyl-3-oxahexanoic acid (PMOH) and 3H-perfluoro-3-[(3-methoxypropoxy) propanoic acid] (PMPP) were weak agonists of human PPARγ. The other human nuclear receptors (PPARδ, CAR, PXR, FXR, LXRα, RXRα and RARα) were not affected by any PFAS tested in this study. Although PMOH was more effective than PFOA in stimulating PPARα in the transactivation assay, it was less effective in stimulating PPARα-dependent target gene expression in human HepG2 hepatocarcinoma cells. Notably, any effect observed in this in vitro study only occurred at concentrations higher than 10 μM of the respective PFAS which is in all cases several magnitudes above the average blood concentration in the Western population. Thus, the results suggest that nuclear receptor activation may only play a minor role in potential PFAS-mediated adverse effects in humans.
... PFAAs are primarily used in industrial and household products, such as fire-fighting foams, surfactants, food packaging, nonstick cookware, and carpets (Lindstrom et al., 2011). Long-chain perfluoroalkyl carboxylic acids [C n F 2n+1 COOH; n ≥ 7 (PFCAs)] and long-chain perfluoroalkyl sulfonic acids [C n F 2n+1 SO 3 H; n ≥ 6 (PFSAs)] were present ubiquitously in various environments and even detected in indoor dust (Björklund et al., 2009;Yao et al., 2016), wildlife (Houde et al., 2011;Zhou et al., 2014) and human blood (Poothong et al., 2017;Zhang et al., 2013). Many countries and organizations have taken actions to restrict or prohibit the production and emissions of long chain PFAAs due to their persistence, bioaccumulation potential, and toxicity. ...
Article
Although human exposure to perfluoroalkyl acids (PFAAs) through tap water is an ongoing concern, knowledge of the PFAAs occurrence in the tap water and the associated transport behaviors of PFAAs in drinking water distribution systems (DWDSs) are scarce. This investigation profiled the occurrence of 17 kinds of PFAAs in tap water of some Chinese cities, and the transport behaviors of PFAAs in DWDS were observed in eastern China. Tap water samples both along trunk pipelines and at the distal ends were collected to display the PFAAs occurrence scenarios. Loose deposit solids were also obtained to reveal their possible accumulation effect on PFAAs. The results showed that perfluorooctanoic acid (PFOA) and perfluorobutanoic acid (PFBA) widely existed in tap water samples, and were the predominant PFAAs in eastern China areas. The mean concentration of the 17 PFAAs was 77.49 ng/L (ranging from 9.29 ng/L to 266.68 ng/L). Short-chain PFAAs (mainly PFBA) concentrations were relatively stable from water treatment plant to consumer taps, while long-chain PFAAs (mainly PFOA) exhibited a significant decrease in concentration, which could be attributed to their accumulation by the loose deposits in the DWDSs. It was calculated that PFOA has a higher partition coefficient than PFBA; this means that the former has a stronger potential to be adsorbed by loose deposits. In addition, the accumulation ability of loose deposits might be associated with the composition of Al, Fe and Si in the loose deposits. The positive correlation between the short-chain PFAAs and dissolved organic carbon (DOC) indicated the possible interactions between PFAA and natural organic matter could favor short-chain PFAAs to retain in bulk water. When water quality conditions change or hydraulic disturbance occur, loose deposits may enter tap water bringing accumulated PFAAs with it, which may result in potential health risks.
... D'Hollander et al. (2010) observed the total intake for the seven PFCs as 0.7 ng day −1 (PFOS = 0.4 ng day −1 ) for economically inactive adults, and 3.5 ng day −1 (PFOS = 2.3 ng day −1 ) for employed adults. Björklund et al. (2009) collected indoor dust samples in the period 2006-2007 in Sweden and determined the median human exposure for PFOS as 0.1 to 22 ng day −1 ; for PFOA it was 0.1 to 19 ng day −1 . ...
... Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are man-made chemicals some with hydrophobicity and some with lipophobicity, which have been widely used in clothing, furniture, carpets, nonstick cookware, and food packaging for the past 60 years (Prevedouros et al., 2006). The major route of nonoccupational exposure to PFASs is dietary via the consumption of contaminated food and drinking water (Haug et al., 2010;Vestergren et al., 2012), followed by indoor air and dust (Bjorklund et al., 2009). Several PFASs, including perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA), have been detected in >98% of serum samples in the US population (Calafat et al., 2007), and similar detection rates were confirmed in Chinese population (Tian et al., 2018). ...
Article
Study question: Are maternal plasma concentrations of perfluoroalkyl and polyfluoroalkyl substances (PFASs) during pregnancy associated with anogenital distance (AGD) in male infants at birth, 6, and 12 months of age? Summary answer: Higher maternal plasma concentrations of some PFASs were associated with shorter AGD in male infants at birth and 6 months of age. What is known already: Two animal studies have found that exposure to PFASs was associated with shorter AGD in male rat fetuses and wild male minks. There is only one human study on the topic that did not identify consistent patterns between maternal serum concentrations of PFASs during pregnancy and AGD in male infants. Study design, size, duration: In the prospective cohort study, a total of 1292 eligible pregnant women were recruited at 12-16 weeks of gestation between April and December 2012 at the Maternal and Child Health Hospital of Minhang district in Shanghai, China. At delivery, 667 male singletons were born. They were then followed up at birth (n = 439) and at 6 (n = 411) and 12 months (n = 376) of age when anopenile distance (AGDAP) and anoscrotal distance (AGDAS) were measured. Participants/materials, setting, methods: A total of 500 male infants who had both maternal plasma concentrations of PFASs and at least one AGD measurement of at three time points were included in the present study. Multiple linear regression models were used to evaluate the potential linear associations between maternal concentrations of PFASs and AGD. Main results and the role of chance: Maternal plasma concentrations (ln-transformed) of perfluorooctane sulfonate (PFOS), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUdA) were inversely associated with AGDAS or AGDAP at birth (AGDAS: per ln unit increase in PFAS concentrations: β (95% CI): -0.65 (-1.27 to -0.02) mm for PFOS; -0.58 (-1.11 to -0.06) mm for PFDA; and -0.57 (-1.09 to -0.06) mm for PFUdA; AGDAP: per ln unit increase in PFAS concentrations: β (95% CI): -0.63 (-1.24 to -0.01) mm for PFDA and - 0.76 (-1.36 to -0.16) mm for PFUdA). At 6 months of age, per unit increase in maternal ln concentrations of PFOS and perfluorotridecanoic acid (PFTrDA), AGDAS decreased on average by -2.21 (95% CI: -4.28 to -0.14) and -1.11 (95% CI: -2.17 to -0.06) mm, respectively. Additionally, ln-transformed perfluorooctanoic acid (PFOA) showed nonsignificant but inverse associations with both AGDAS and AGDAP at 6 months of age. We found no significant associations between ln-transformed maternal concentrations of PFASs and either AGDAS or AGDAP at 12 months of age. However, significantly inverse association of ln-transformed PFOA with AGDAP was observed in male infants who never or shortly breastfed (<3 months) at 12 months of age. Limitations, reasons for caution: AGD measurements were performed by different examiners at each follow-up visit, and the intra-examiner variation was not assessed, which might cause intra-rater and inter-rater measurement errors. Additionally, our study may have selection bias since a considerable number of participants withdrew from the cohort although the differences in demographic characteristics were not statistically significant between included mother-infant pairs and those excluded. No statistical correction was made for multiple comparisons. Wider implications of the findings: Our findings may have important implications for the early development of genital health in male infants since PFASs can be detected in almost all pregnant women and infants worldwide. Study funding/competing interest(s): This study was supported by grants from the National Key Research and Development program of China (2018YFC1002801 and 2016YFC1000505), the Science and Technology Commission of Shanghai Municipality (16ZR1430100), the National Natural Science Foundation of China (81428011), and the Innovation-Oriented Science and Technology Grant from National Health Commission Key Laboratory of Reproduction Regulation (CX2017-06). The authors have no conflicts of interest to declare. Trial registration number: N/A.
... Previous studies conducted in North America, Asia, and Europe have also found PFAAs to be common house dust contaminants . While dietary exposure is considered the dominant exposure pathway for the general population, exposure models have found that incidental ingestion of contaminated house dust may be the second-most important or dominating pathway of exposure to PFAAs for infants and children [15,16,30,31]. ...
Article
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The Minnesota Department of Health measured levels of perfluoroalkyl acids (PFAAs) in house dust at homes in communities impacted by PFAA-contaminated soil and drinking water to determine whether PFAAs in soil outside the home are associated with concentrations in dust. House dust samples from both interior living spaces and entryways to the yard were collected and analyzed separately based on the presumption that PFAAs in entryway dust may better reflect “track-in” of PFAAs into the home from contaminated soil or lawns irrigated with contaminated water. PFAA detections and concentrations in living rooms were significantly higher compared to entryways; and concentrations in both sampling locations were higher than corresponding soil concentrations, suggesting that interior sources were the main contributors to PFAAs in house dust. PFAA dust concentrations in entryways were significantly associated with living room dust levels for all analytes except PFBA. Relationships between entryway dust and soil were only seen for one PFAA (PFOA). However, median concentrations of PFOA in entryway and living room dust were 35 and 70 times higher (respectively) than in soil, which highlights the lack of importance of PFAA soil track-in as a contributor to dust concentration in this setting. Due to the small sample size, larger scale studies are needed to further assess the potential for migration of PFAA contaminated soil to indoor dust.
... Since PFCs are not easily degraded, they accumulate in the environment and animals. Therefore, people have raised many concerns about the potential adverse impact of PFCs on our health (Bjorklund et al., 2009;Paul et al., 2009). ...
Article
PFOS and PFOA are two of the most abundant perfluorinated compounds (PFCs) in the environment. Previous studies have reported they have a long half-life (up to five years) once they enter into the human body. Moreover, they can potentially promote the adipogenic process by activating PPARγ. However, little is known about PFOS and PFOA chronic health impacts on humans. In this study, we employed primary human mesenchymal stem cells (hMSCs) and demonstrated that PFOS and PFOA exerted acute cytotoxicity and affected adipogenesis and osteogenesis at environmental and human relevant doses. In fact, PFOS and PFOA impaired the proper expression of CD90 (a surface antigen highly enriched in undifferentiated hMSCs) and promoted adipogenesis, presumably via their interaction with PPARγ. Moreover, PFOA partly disturbed osteogenesis. Thus, our findings not only validated the health risks of PFOS and PFOA, but also revealed new potential long-term PFOS/PFOA impacts on humans.
... To date, PFOA has been ubiquitously detected in various environmental media, such as dust, soil, surface water, sediment, fish, and even human blood (Björklund et al., 2009;T. Wang et al., 2015). ...
Article
Perfluorooctanoic acid (PFOA) has long been produced and widely used due to its excellent water and oil repellent properties. However, this trend has facilitated to the ubiquitous existence of PFOA in environmental matrix, and the potential ecotoxicity on aquatic organisms has not been fully elucidated. To study the tissue-specific bioconcentration and the nervous system- and energy-related biochemical effects of PFOA, as well as the phenotypic alterations by this chemical, male crucian carp (Carassius auratus) were exposed to gradient concentrations of PFOA (nominal 0.2, 10, 500 and 25,000 μg/L) in a flow-through apparatus for 7 days. PFOA was enriched in tissues following an order of blood > kidney ≥ liver > gill > brain > muscle. The bioconcentration factors ranged from 0.1 to 60.4. Acetylcholinesterase activity in the fish brain was inhibited, while liver carboxylesterase was induced in most cases and attenuated with time. The acyl-CoA oxidase activity was dose-dependently elevated and accompanied by a decline of ATP contents. PFOA treatments also inhibited the activity of the electron transport system (ETS). At the transcriptional level, ETS component complexes II and IV were concordantly depressed, and ATP synthesis was also downregulated. The mRNA level of peroxisome proliferator activated receptor α was increasingly upregulated, with related downstream genes upregulated in varying degrees. The phenotypes showed patterns of increased liver pathology and reduced swimming activity. In summary, PFOA leads to adverse effects in Carassius auratus related to multiple aspects, which may be associated with the nervous system, fundamental energy metabolism and other unpredictable factors. The results obtained in this study are expected to help clarify the PFOA toxic mechanisms on energy relevance.
... Winkens et al., 2017b Such changes include for instance diet (from breast milk to baby food and finally to solid food), but also the amount of consumed food or water related to the body weight, and a peak in dust ingestion rates and frequency in hand to mouth contact events between the age of 1 and 3 years ( ). Exposure via dust ingestion and/or Winkens et al., 2017b direct contact with consumer products for toddlers may, therefore, help to explain the increasing body burdens post lactation (Björklund et al., 2009Shoeib et al., 2011), or even the delayed increase of PFOS body burdens between 6 and 10.5 years. ...
Article
Full-text available
Studies suggest negative health impacts from early life exposure to per-and polyfluoroalkyl substances (PFASs). However, information on longitudinal exposure to PFASs during childhood is scarce for background-exposed individuals. This study sought to fill this gap by investigating children's longitudinal exposure trends through measurement of PFAS serum concentrations and calculation of body burdens (μg, total in body). Blood of 54 Finnish children was sampled 2005-2015 and analyzed for 20 PFASs at 1, 6 and 10.5 years of age. The body burden was calculated by multiplying the serum concentration by the volume of distribution and the bodyweight for each individual. Associations between serum concentrations or body burdens and parameters, such as sex, breastfeeding duration, body mass index as well as indoor dust and air PFAS concentrations, were evaluated. Serum concentrations of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), per-fluorononanoic acid (PFNA) and perfluorohexane sulfonic acid (PFHxS) decreased significantly (p < 0.001) with age. In contrast to serum concentrations, body burdens stayed unchanged or even increased significantly (p < 0.05), except for PFOA in female children. Breastfeeding duration was positively correlated (p < 0.001) with serum concentrations of PFHxS, PFOS, PFOA and PFNA at 1 year of age. Some associations were found at 10.5 years with sex and indoor PFAS concentrations. Observations of longitudinal decreasing trends of serum concentrations can be misleading for understanding exposure levels from external media during childhood, as the serum concentration is influenced by parallel temporal changes and growth dilution. Body burdens account for growth dilution and thus better reflect differences in early-life to adolescence exposure than serum concentrations .
... Perfluorooctanoic acid (PFOA) is one of the most important perfluorinated organic compounds: it possesses unique physicochemical properties and has been widely used in industrial and consumer applications [1][2][3]. Recently, PFOA has received much attention because it is extremely persistent in the environment and is detected in groundwaters [4], sediments [5] and human beings worldwide [6]. In addition, PFOA is resistant to most conventional reduction and oxidation processes as well as biological degradation, due to the strong C-F bond [7][8][9]. ...
Article
Perfluorooctanoic acid (PFOA) is of emerging concern owing to its global distribution and environmental persistence. Efficient degradation approaches are so far limited. Herein, we demonstrate for the first time the photochemical degradation of PFOA under UV-A irradiation after adsorption on Fe-doped zeolites with molecular oxygen as the terminal oxidant. In a system containing 1 g L⁻¹ PFOA-loaded Fe-zeolites, outstanding PFOA decomposition (> 99%) was achieved within 24 h under slightly acidic conditions (pH ≤ 5.5). Short-chain perfluorinated carboxylic acids (PFCAs) are the main intermediates, beside fluoride and CO2. No PFOA degradation occurs with Fe-free zeolites or dissolved ferric ions. Furthermore, we investigated the effects of pH, inorganic ions and gas atmospheres on PFOA degradation. A photochemical degradation mechanism with zeolite-bound iron species as catalytic sites for carboxylate-to-metal charge transfer is proposed. The presented study offers a novel approach for the removal of the highly recalcitrant PFOA from contaminated waters.
... The sources of PFASs in the indoor environment were generally common, such as carpets, outdoor equipment, and paper products. 69,70 Although the indoor environment was a primary source of PFASs in the outdoor environment, outdoor specific sources like fluorination plants were also important contributing factors to contamination by PFASs. Actually, a large number of PFASs with low detection frequencies were noted in CS, JN, and NJ, all of which are industrial cities (Figure 2 and SI Table S8). ...
Article
Airborne particulate matter (APM) has an important role in inhalation exposure, especially in China. The environmental occurrence of conventional and unknown per- and polyfluoroalkyl substances (PFASs) in APM remains unclear. Therefore, in this study, a two-stage experiment was designed to identify potential PFASs and to investigate their distribution in APM. Indoor and outdoor APM samples were collected from five selected cities in China. Through PFAS homologue analysis and suspect screening, 50 peaks were identified with different confidence levels (levels 1–3). Among the identified PFASs, 34 emerging PFASs including p-perfluorous nonenoxybenzenesulfonate, 6:2 polyfluoroalkyl phosphate diester, n:2 fluorotelomer sulfonates, n:2 fluorinated telomer acids, n:2 chlorinated polyfluoroalkyl ether sulfonic acids, 1:n polyfluoroalkyl ether carboxylic acids (1:n PFECAs), perfluoroalkyl dioic acids (PFdiOAs), hydro-substituted perfluoroalkyl dioic acids (H-PFdiOAs), and unsaturated perfluorinated alcohols (UPFAs) were identified in APM. In particular, 1:n PFECAs, PFdiOAs, H-PFdiOAs, and UPFAs were first detected in APM. Although human exposure to perfluorooctanoic acid via inhaled APM was noted to not be a risk (hazard quotient <0.1) in this study, the expansion of the PFASs screened in APM implies that human exposure to PFASs might be much more serious and should be considered in future risk assessments in China.
... Human exposure to PFAS can result from various sources such as food, beverages (including drinking water), inhalation and in-house dust contaminated by PFAS from different consumer products such as textiles and impregnation products (Strynar and Lindstrøm, 2008;Bjørklund et al., 2009;Ericson et al., 2008;EFSA, 2011). ...
... PFOA and its derivatives are found in consumer products like, e.g., carpets and furnishing, cookware, food papers, and clothing (Egeghy and Lorber 2011;Goosey and Harrad 2011;Verner et al. 2015). The presence of PFOA on house dust is ubiquitous from all over the Responsible Editor: Philippe Garrigues * Åsa Gustafsson asamgus@gmail.com.se 1 world (Björklund et al. 2009;Byrne et al. 2017;D'Hollander et al. 2010;Eriksson and Kärrman 2015;Goosey and Harrad 2011;Haug et al. 2011b;Huber et al. 2011;Kato et al. 2009;Knobeloch et al. 2012;Kubwabo et al. 2005;Moriwaki et al. 2003;Schoeib et al. 2016;Xu et al. 2013;Tian et al. 2016;Weiss et al. 2021;and Winkens et al. 2018). Considering that PFAS are extensively used in indoor products and owing to the long time that we spend indoors daily (approximately 90%), it is of great importance to determine the bioavailability of PFOA from house dust via relevant exposure pathways. ...
Article
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Indoor environments may impact human health due to chemical pollutants in the indoor air and house dust. This study aimed at comparing the bioavailability and distribution of PFOA following both an inhalation and an oral exposure to PFOA coated house dust in rats. In addition, extractable organofluorine (EOF) was measured in different tissue samples to assess any potential influence of other organofluorine compounds in the experimental house dust. Blood samples were collected at sequential time points after exposure and at the time of termination; the lungs, liver, and kidney were collected for quantification of PFOA and EOF. The concentration of PFOA in plasma increased rapidly in both exposure groups attaining a C max at 3 h post exposure. The C max following inhalation was four times higher compared to oral exposures. At 48 h post exposure, the levels of PFOA in the plasma, liver, and kidney were twice as high from inhalation exposures. This shows that PFOA is readily bioavailable and has a rapid systemic distribution following an inhalation or oral exposure to house dust coated with PFOA. The proportion of PFOA to EOF corresponded to 65–71% and 74–87% in plasma and tissues, respectively. The mass balance between EOF and target PFOA indicates that there might be other unknown PFAS precursor and/or fluorinated compounds that co-existed in the house dust sample that can have accumulated in rats.
... The detection of perfluoroalkyl substances (PFASs) specifically perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) in the water [1], air [2,3], blood, wastewater [4], fishes [5] is widely reported in the literature [6]. The toxicological studies on an animal show that PFOA and PFOS change functions of some of the organ in the body and alter the hormones at relatively higher concentration [7]. ...
Article
Ultrasonic breakdown of perfluorooctanoic acid and perfluorooctane sulfonic acid were evaluated at various ultrasonic frequency (575 kHz, 860 kHz, and 1140 kHz), pH (3 - 12), bulk water temperature (14.5 - 30 oC), and gases (Helium, Nitrogen, Oxygen, Ozone, Argon). Contrary to the result reported in the literature, we observed an increase in the rate kinetics of PFOA and PFOS decomposition in an air environment (i.e., without sparging any gases), at higher pH, and higher bulk water temperature. The rate kinetics of PFOA degradation in gases follows the order as Helium>Nitrogen>Argon>Oxygen>Ozone. The present work concludes that the presence of known/unknown chemical compounds, formed during sonolysis, influence the interaction of PFOA and PFOS with the cavity-water interface. The cavity collapse simulation using Gilmore equation showed that an increase in acoustic pressure increases the compression ratio and bubble radial velocity of the collapsible cavity. This study suggests that the lower degradation rate of PFOS as compared to PFOA, over a range of ultrasound frequencies, is due to the lower number of active cavities collapsing at higher temperatures. The radius of active collapsible cavities, with maximum compression ratio and bubble radial velocity, was 3.2 µm, 2 µm, and 1.7 µm at an ultrasonic frequency of 575 kHz, 860 kHz, and 1140 kHz, respectively
... (Dinglasan et al., 2004;Wang et al., 2005aWang et al., , 2005b. In weiteren Versuchen von Ellis et al. (2003Ellis et al. ( , 2004 (Begley et al., 2005;Key et al., 1997;Pfaff, 2006 (Anonymus, 2002a, Drobny, 2001Wall, 1972 (Begley et al., 2005;Hajslova et al., 2011;Pfaff, 2006 (So et al., 2004;Taniyasu et al., 2002Taniyasu et al., , 2003 (Björklund et al., 2009;Fromme et al., 2008;Katsumata et al., 2006;Kubwabo et al., 2005;Moriwaki et al., 2003;Strynar & Lindström, 2008). Natürlich können ebenso regionale und wetterbedingte Unterschiede die Werte beeinflussen, jedoch scheinen vielmehr die über die letzten Jahre verringerten PFOS-Gehalte in Teppichböden der Grund für den Rückgang zu sein (Boulanger et al., 2005;Washburn et al., 2005 funden. ...
Thesis
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Perfluorinated alkylated substances, persistent and partly bioaccumulative com-pounds, including perfluorinated carboxylic acids and perfluorinated sulphonic acids, have been and are identified both in our daily diet and oleophobic coated food con-tact papers. Thus contamination of food by a transfer of these compounds, described as carcinogen, from packaging into packed food items is discussed. In addition, de-tected amounts of fluorinated telomere alcohols (FTOHs) in paper packaging could cause a further increase in exposition, since they are known as precursor substances for perfluorinated carboxylic acids. The focus of this work was to perform migration and emission tests on FTOHs from food contact papers using four paper packaging as well as twelve test media. There-fore, test parameters (temperature, time, test medium) were varied taking into ac-count the application area of the respective food contact paper. The analysis of the measurement devices occur both quantitative (migration) and qualitative (emission). For migration tests additional methods for clean-up of prepared test media and paper samples were developed by experiments with different solvents and SPE-cartridges. The developed methods for clean-up were sufficiently sensitive and generated repro-ducible results. Migration was predominantly a function of temperature and time and displayed additional a dependence on the test medium. Transfers of FTOHs up to 92 μg/dm² were detected in test media. Amounts above the migration rate of 100% indicated a reproduction of FTOHs from precursor substances, which was attested in further investigations. In the emission tests a temperature- and time-dependent in-crease of the amounts of FTOHs was also determined. Since the migration depends on the emission, the results of the migration tests were consequently attested.
... We found direct associations between 4-hydroxyactophenone, PFHxS and bile acids, including sulfolithocholylglycine, lithocholic acid glycine and chenodeoxycholic acid (CDCA) in women FF. PFHxS is a perfluoroalkyl substance (PFAS) used as an additive in a wide range of consumer products and food packaging due to surfactant and stain resistant properties 26 . PFAS are also components of firefighting foam and firefighter's protective clothing, so these are possible sources of exposure for women FF. ...
Article
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Given the complex exposures from both exogenous and endogenous sources that an individual experiences during life, exposome-wide association studies that interrogate levels of small molecules in biospecimens have been proposed for discovering causes of chronic diseases. We conducted a study to explore associations between environmental chemicals and endogenous molecules using Gaussian graphical models (GGMs) of non-targeted metabolomics data measured in a cohort of California women firefighters and office workers. GGMs revealed many exposure-metabolite associations, including that exposures to mono-hydroxyisononyl phthalate, ethyl paraben and 4-ethylbenzoic acid were associated with metabolites involved in steroid hormone biosynthesis, and perfluoroalkyl substances were linked to bile acids—hormones that regulate cholesterol and glucose metabolism—and inflammatory signaling molecules. Some hypotheses generated from these findings were confirmed by analysis of data from the National Health and Nutrition Examination Survey. Taken together, our findings demonstrate a novel approach to discovering associations between chemical exposures and biological processes of potential relevance for disease causation.
... Perfluoroalkyl substances (PFASs) are highly stable aliphatic fluorinated compounds [1]. Some of the PFASs, such as perfluorooctanoic acid (PFOA) and perfluoroctane sulphonic acid (PFOS), are emerging contaminants of concern due to their widespread use in commercial and industrial products in the past [2] and potential toxicity [3]. PFOA and PFOS are listed in the United Nations' persistent organic pollutants (POPs) list to eliminate and restrict production. ...
Article
The power density modulates the dynamics of the chemical reactions during the ultrasonic breakdown of organic compounds. We evaluated the ultrasonic degradation of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) at various power densities (30 W/L-262 W/L) with and without sparging Argon. We observed pseudo-first-order degradation kinetics at an initial PFASs concentration of 100 nM over a range of power density. The rate kinetics of degradation shows a non-linear increase with an increase in power density. We proposed a four-parameter logistic regression (4PLR) equation that empirically fits the degradation rate kinetics with the power density. The 4PLR equation predicts that the maximum achievable half-life of PFOA and PFOS sonochemical degradation are 1 and 10 min under a given set of experimental conditions. The high bulk-water temperature (i.e., 30°C) of the aqueous sample helps increase the degradation rate of PFOA and PFOS. The addition of oxidants such as iodate and chlorate help enhance PFOA degradation in an argon environment at an ultrasonic frequency of 575 kHz.
Article
Semi-volatile organic compounds (SVOCs) can be found in air, dust and on surfaces in car cabins, leading to exposure to humans via dust ingestion, inhalation, and dermal contact. This review aims at describing current understanding concerning sampling, levels, and human exposure of SVOCs from car cabin environments. To date, several different methods are used to sample SVOCs in car cabin air and dust and there are no standard operating procedures for sampling SVOCs in cars detailed in the literature. The meta-analysis of SVOCs in car cabin air and dust shows that brominated flame retardants (BFRs) and organophosphate flame retardants (OPFRs) have been most frequently studied, primarily focusing on concentrations in dust. In dust, detected concentrations span over three to seven orders of magnitude, with highest median concentrations for OPFRs, followed by BFRs and, thereafter, polychlorinated biphenyls (PCBs). In air, the variation is smaller, spanning over one to three orders of magnitude, with phthalates and siloxanes having the highest median concentrations, followed by OPFRs, fluorotelomer alcohols (FTOHs) and BFRs. Assessments of human exposures to SVOCs in cars have, so far, mainly focused on external exposure, most often only studying one exposure route, primarily via dust ingestion. In order to perform relevant and complete assessments of human exposure to SVOCs in cars, we suggest broadening the scope to which SVOCs should be studied, promoting more comprehensive external exposure assessments that consider exposure via all relevant exposure routes and making comparisons of external and internal exposure, in order to understand the importance of in-car exposure as a source of SVOC exposure. We also suggest a new sampling approach that includes sampling of SVOCs in both car cabin air and dust, aiming to reduce variability in data due to differences in sampling techniques and protocols.
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Recently, the CnF2nO species have received much attention in the field of alternative gases, particularly C5F10O and C6F12O, both of which have a very low global warming potential (GWP) and excellent insulation properties. Due to its excellent insulation performance, foreign scientific research institutions and companies begin to study the material and its mixture, and there are few studies on its decomposition characteristics under discharge. In this paper, based on the density functional theory, the stability of C5F10O and its possible decomposition path were analyzed. At first, the ionization energy of C5F10O was calculated, and the possible position of the reaction in the molecular structure was determined based on the frontier molecular orbital theory. Secondly, the possible decomposition pathway of C5F10O, the formation mechanism of the decomposition products and the corresponding energy changes were analyzed. Finally, the C5F10O/N2 gas mixture was tested by using gas insulated test platform,the gas components in the gas chamber before and after breakdown were analyzed based on gas chromatography mass spectrometry (GC-MS), the insulation properties of the decomposition products and the dynamic equilibrium processes of various particles during the discharge process were discussed. The results show that the formation of CF3CO•, C3F7• or C3F7CO•, CF3• radicals is most likely to occur during the decomposition of C5F10O, and further reactions of various free radicals will generate CF4, C2F6, C3F8, C3F6, C4F10, C5F12, C6F14. The products have strong insulating properties, and the dynamic equilibrium between C5F10O molecules and free radicals exists, both of which ensure the insulation performance of the system. The test results showed that with the increase of breakdown times, the content of C5F10O decomposition products increased, and the growth rate of CF4, C2F6 and C4F10 was higher than that of C3F8 and C6F14.The conclusions provide theoretical basis for further research of insulation properties and synergistic effect of C5F10O gas mixture, and provide a reference for the study of CnF2nO environmental- friendly medium.
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We present fluorocarbon-free block copolymer brushes as potential systems for dual-action, i. e. soil-repellent and soil-releasing textile finishes. Polymer brushes were prepared by employing specifically engineered triblock copolymers consisting of a hydrophobic, a hydrophilic and either a central or a terminal anchor block bearing several anchoring groups for sustainable immobilization using the “grafting-to” approach on both, flat Si wafers and rough cotton fabrics. The switching characteristics of both types of block copolymer brushes were investigated by exposing the brushes to conditions and stimuli, that are similar to those applied during laundering in a washing machine and drying in a laundry dryer, respectively. Contact angle measurements were conducted in order to evaluate the polarity and the wettability of the block copolymer brushes after treatment in hot water and in air or in vacuum at elevated temperatures simulating the washing and the drying procedure of a textile fabric. While the block copolymer brush with the terminal anchor showed only minor changes in terms of the wetting characteristics and the brush morphology upon the applied stimuli, the block copolymer brush with the central anchoring block exhibited a significant change from a hydrophilic (soil-releasing) to a hydrophobic (stain-repellent) surface. This switching behavior was reversible and could be achieved on both, flat Si wafers, and much more pronounced on rough cotton fabrics. AFM and angle-resolved XPS investigations further indicated a complete rearrangement of the brush morphology. Accordingly, we regard this type of block copolymer brushes as a system that fully meets the basic requirements for an application as a dual-action textile finish, which can be reversibly switched with respect to water repulsion.
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Per-fluoroalkyl and polyfluoroalkyl substances (PFAS) are a diverse group of synthetic fluorinated chemicals used widely in industry and consumer products. Due to their extensive use and chemical stability, PFAS are ubiquitous environmental contaminants and as such, form an emerging risk factor for male reproductive health. The long half-lives of PFAS is of particular concern as the propensity to accumulate in biological systems prolong the time taken for excretion, taking years in many cases. Accordingly, there is mounting evidence supporting a negative association between PFAS exposure and an array of human health conditions. However, inconsistencies among epidemiological and experimental findings have hindered the ability to definitively link negative reproductive outcomes to specific PFAS exposure. This situation highlights the requirement for further investigation and the identification of reliable biological models that can inform health risks, allowing sensitive assessment of the spectrum of effects of PFAS exposure on humans. Here, we review the literature on the biological effects of PFAS exposure, with a specific focus on male reproduction, owing to its utility as a sentinel marker of general health. Indeed, male infertility has increasingly been shown to serve as an early indicator of a range of co-morbidities such as coronary, inflammatory, and metabolic diseases. It follows that adverse associations have been established between PFAS exposure and the incidence of testicular dysfunction, including pathologies such as testicular cancer and a reduction in semen quality. We also give consideration to the mechanisms that render the male reproductive tract vulnerable to PFAS mediated damage, and discuss novel remediation strategies to mitigate the negative impact of PFAS contamination and/or to ameliorate the PFAS load of exposed individuals.
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Per- and poly-fluoroalkyl substances (PFAS) are a group of recalcitrant compounds whose widespread use in a variety of consumer products has led to contamination of groundwater and surface water systems. Foam fractionation is a potential remediation technology for treatment of PFAS contaminated water, which takes advantage of the high surface activity imparted by the fluorocarbon chain to remove them from solution by adsorption to the surface of air bubbles. In this study, the effect of mono- and di-valent cations on the performance of a PFAS foam fractionation process where sodium dodecyl sulphate (SDS) is used as a co-foaming agent has been evaluated. The results indicated that the separation of PFAS was improved in an order that followed the charge density of the salts with Mg²⁺ > Na⁺ > K⁺. It was also observed that at salt concentrations above 100 mM for Na⁺, above 10 mM for K⁺ and Mg²⁺ but between 0.1 and 10 mM for Ca²⁺ in the presence of greater than 4 ppm of SDS, the cations can complex with the SDS in the system and suppress foam formation due to the surfactant precipitation. Foam fractionation was able to remove perfluorohexane sulphonic acid (PFHxS), perfluorooctanoic acid (PFOA) and perfluorooctane sulphonic acid (PFOS) from a sample of Australian groundwater to below the analytical detection limit of 0.1 ppb within 60 minutes with SDS being used as the co-foaming agent, but was unable to remove the short chain perfluorobutanoic acid (PFBA).
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Indoor environments may impact human health due to chemical pollutants in the indoor air and house dust. This study aimed at comparing the bioavailability and distribution of PFOA following both an inhalation and an oral exposure to PFOA coated house dust in rats. In addition, extractable organofluorine (EOF) was measured in different tissue samples to assess any potential influence of other organofluorine compounds in the experimental house dust. Blood samples were collected at sequential time points after exposure and at the time of termination; lung, liver and kidney were collected for quantification of PFOA and EOF. The concentration of PFOA in plasma increased rapidly in both exposure groups attaining a C max at 3 h post exposure. The C max following inhalation was four times higher compared to oral exposures. At 48 h post exposure, the levels of PFOA in plasma, liver and kidney were twice as high from inhalation exposures. This shows that PFOA is readily bioavailable and has a rapid systemic distribution following an inhalation- or oral exposure to house dust coated with PFOA. The proportion of PFOA to EOF corresponded to approximately 54-68% and >80% in plasma and tissues, respectively. The mass balance between EOF and target PFOA indicate that there might be other unknown PFAS precursor and/or fluorinated compounds that co-existed in the house dust sample that might have accumulated in rats.
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Perfluoroalkyl acids (PFAAs) are emerging persistent organic pollutants that are globally distributed in the environment. PFAAs are mainly derived from the emissions of fluoride manufactures and their downstream industry. In the present review, the study on the occurrence of PFAAs and their behavior in aquatic ecosystem were summarized, and the health and ecological risk assessment and the multimedia fate simulation were investigated. PFAAs are most likely to exist in the aqueous phase, and PFAAs in atmosphere are also able to enter water bodies through diffusion and wet and dry deposition and eventually become widely distributed in various environmental media. The air-solid partition is considered to be one of the major factors in the long-distance transportation of the pollutants. The pKa values and organic carbon fraction of the sediment could influence the partition of PFAAs between water and sediment. Otherwise, PFAAs have teratogenic, mutagenic and other toxic effects and they could be accumulated by biota, and magnified through trophic level. The ecological and health risks of PFOA and PFOS were assessment. In order to explore the partition mechanism and reduce the uncertainty of the simulation of the transport, transformation and fate, the experimental methods on physicochemical properties of PFAAs should be developed. Moreover, further studies on toxicities of PFAAs are necessary for health and ecological risk assessment.
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Anti-fog sprays and solutions are used on eyeglasses to minimize the condensation of water vapor, particularly while wearing a mask. Given their water-repellent properties, we sought to characterize per- and polyfluorinated alkyl substance (PFAS) compounds in four anti-fog spray products, five anti-fog cloth products, and two commercial fluorosurfactant formulations suspected to be used in preparing anti-fog products. Fluorotelomer alcohols (FTOHs) and fluorotelomer ethoxylates (FTEOs) were detected in all products and formulations. While 6:2 FTOH and the 6:2 FTEO polymeric series were predominant, one anti-fog cloth and one formulation contained 8:2, 10:2, 12:2, 14:2, and 16:2 FTOH and FTEO polymeric series. PFAS concentrations varied in samples and were detected at levels up to 25,000 μg/mL in anti-fog sprays and 185,000 μg (g cloth)⁻¹ in anti-fog cloth products. The total organic fluorine (TOF) measurements of anti-fog products ranged from 190 to 20,700 μg/mL in sprays and 44,200 to 131,500 μg (g cloth)⁻¹ in cloths. Quantified FTOHs and FTEOs accounted for 1–99% of TOF mass. In addition, all four anti-fog sprays and both commercial formulations exhibited significant cytotoxicity and adipogenic activity (either triglyceride accumulation and/or pre-adipocyte proliferation) in murine 3T3-L1 cells. Results suggest that FTEOs are a significant contributor to the adipogenic activity exhibited by the anti-fog sprays. Altogether, these results suggest that FTEOs are present in commercial products at toxicologically relevant levels, and more research is needed to fully understand the health risks from using these PFAS-containing products.
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Pregnancy is a complex process requiring tremendous physiological changes in the mother in order to fulfill the needs of the growing fetus, and to give birth, expel the placenta and nurse the newborn. These physiological modifications are accompanied with psychological changes, as well as with variations in habits and behaviors. As a result, this period of life is considered as a sensitive window as impaired functional and physiological changes in the mother can have short- and long-term impacts on her health. In addition, dysregulation of the placenta and of mechanisms governing placentation have been linked to chronic diseases later-on in life for the fetus, in a concept known as the Developmental Origin of Health and Diseases (DOHaD). This concept stipulates that any change in the environment during the pre-conception and perinatal (in utero life and neonatal) period to puberty, can be “imprinted” in the organism, thereby impacting the health and risk of chronic diseases later in life. Pregnancy is a succession of events that is regulated, in large part, by hormones and growth factors. Therefore, small changes in hormonal balance can have important effects on both the mother and the developing fetus. An increasing number of studies demonstrate that exposure to endocrine disrupting compounds (EDCs) affect both the mother and the fetus giving rise to growing concerns surrounding these exposures. This review will give an overview of changes that happen during pregnancy with respect to the mother, the placenta, and the fetus, and of the current literature regarding the effects of EDCs during this specific sensitive window of exposure.
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Foam fractionation is a well-developed technology used to separate surface-active compounds from solution by exploiting their affinity for the air–water interface. The technology was founded in the 1940s and has since evolved into a key technology for treatment of many different pollutants from a variety of different industries such as textiles and dyes, heavy metals, proteins in food processing waste and even per- and poly-fluoroalkyl substances (PFAS). The technology has even progressed from a standard batch process to a continuous process with an applied reflux to being presently used as an in-situ groundwater remediation and soil remediation process. This review provides a snapshot of the historical evolution of foam fractionation, a discussion of the mechanism behind foam fractionation, the effect of key operating variables on the performance parameters, identification of the key transport processes that take place within a foam fractionation system, a review of the modeling of foam fractionation as a water treatment technology and a review of the applications of foam fractionation as a water treatment technology.
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The occurrence of perfluoroalkyl substances (PFASs) was for the first time investigated in various working microenvironments (internet cafes, electronics shops, coffee shops, restaurants, etc.) in Thessaloniki, Greece, using the dust trapped by central air conditioner (A/C) filters. Perfluorooctane sulfonic acid (PFOS) was found in the range from 16 to 227 ng g-1, however it was detectable in only 30% of samples. On the contrary, perfluorohexanoic acid (PFHxA) was found in 85% of samples in the range from 3.6 to72.5 ng g-1, while 90-95% of samples exhibited perfluorooctanoic acid (PFOA), perfluorodecanoic acid (PFDcA) and perfluorododecanoic acid (PFDoDA) in the range from 10−653 ng g-1, 3.2-7.4 ng g-1 and 3.8-13.1 ng g-1, respectively. The PFAS profile varied largely among the different microenvironment categories suggesting different sources. Estimated daily intakes through dust ingestion were calculated.
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Given the complex exposures from both exogenous and endogenous sources that an individual experiences during life, exposome-wide association studies that interrogate levels of small molecules in biospecimens have been proposed for discovering causes of chronic diseases. We conducted a study to explore associations between environmental chemicals and endogenous molecules using Gaussian graphical models (GGMs) of non-targeted metabolomics data measured in a cohort of California women firefighters and office workers. GGMs revealed many exposure-metabolite associations, including that exposures to mono-hydroxyisononyl phthalate, ethyl paraben and 4-ethylbenzoic acid were associated with metabolites involved in steroid hormone biosynthesis, and perfluoroalkyl substances (PFAS) were linked to bile acids, hormones that regulate cholesterol and glucose metabolism, and inflammatory signaling molecules. Some hypotheses generated from these findings were confirmed by analysis of data from the National Health and Nutrition Examination Survey (NHANES). Taken together, our findings demonstrate a novel approach to discovering associations between chemical exposures and biological processes of potential relevance for disease causation.
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Background: Studies in male firefighters have demonstrated increased exposures to carcinogenic compounds and increased rates of certain cancers compared to the general population. Many chemicals related to these occupational exposures have been associated with breast tumor development in animal and human studies, yet, there have been no studies on women firefighters due to their low numbers in most fire departments. To address this data gap, the Women Firefighters Biomonitoring Collaborative (WFBC) created a biological sample archive and analyzed levels of perfluoroalkyl substances (PFAS) among women firefighters and office workers in San Francisco. Methods: Active duty women firefighters (n=86) and office workers (n=84) were recruited from the San Francisco Fire Department and the City and County of San Francisco, respectively. Serum samples were collected and analyzed using liquid chromatography tandem mass spectrometry (LC MS/MS) to measure and compare PFAS levels between firefighters and office workers. For PFAS congeners detected in at least 70% of our study population, we examined differences in serum PFAS levels controlling for dietary, demographic and other confounders. Among firefighters, we assessed associations between occupational activities and PFAS levels. Results: Eight of 12 PFAS congeners were detected at levels above the limit of detection and seven were detected in at least 70% of the study population. Four PFAS were detected in all study participants (PFNA, PFOA, PFOS, PFHxS). In regression models comparing PFAS levels by occupation and adjusting for potential confounders, firefighters had higher geometric mean (GM) concentrations of PFAS compared to office workers: 2.39 (95%CI = 1.64,3.48), 2.32 (95% CI = 1.17,4.62) and 1.26 (95% CI = 0.99, 1.59) times higher for PFHxS, PFUnDA and PFNA, respectively. In analyses limited to firefighters, PFAS levels varied by assigned position in the fire department. Firefighters and officers had higher PFNA, PFOA, PFDA, and PFUnDA compared to drivers. Additionally, firefighters who reported having used firefighting foam had higher concentrations of PFOA compared firefighters who reported never having used foam. Conclusion: Our study found ubiquitous exposures to PFAS among WFBC participants, with women firefighters exposed to higher levels of some PFAS compared to office workers, suggesting that some of these exposures may be occupationally related.
Article
Perfluoroalkyl substances (PFASs) were measured in air and dust from cars, homes, offices, and school classrooms in Ireland, along with drinking water from homes and offices. Perfluorooctanoic acid (PFOA) dominated air and drinking water, while perfluorobutane sulfonate (PFBS) dominated dust. This is the first report of PFOA, perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), PFBS, and perfluorononanoic acid (PFNA) in air inside cars and school classrooms. PFOS concentrations in classroom air exceeded significantly (p ≤ 0.05) those in homes. Atmospheric concentrations of PFOA, PFNA, and methyl perfluorooctane sulfonamido ethanol (MeFOSE) (p ≤ 0.05) were significantly higher in cars containing child car seats than in cars without. PFOS, PFOA, PFBS, and PFHxS were all detected frequently in drinking water, but concentrations of PFASs were low, and although ΣPFASs were 64 ng/L in one bottled water sample, this fell below a Swedish Action Level of 90 ng ΣPFASs/L. The Irish population's exposure to PFOS and PFOA via non-dietary sources is well below estimates of dietary exposure elsewhere in Europe. Moreover, even under a high-end exposure scenario, it falls below the European Food Safety Authority's (EFSA) provisional tolerable weekly intakes for PFOS and PFOA.
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Recently, the C4F7N/CO2 mixture has been highly considered as a promising SF6 alternative due to its low greenhouse effect and excellent electrical performance. Apart from its dielectric strength and arc-quenching capability, the decomposition characteristics of C4F7N/CO2 also play an important role in its future applications in gas-insulated electrical equipment. Therefore, decomposition experiments of the C4F7N/CO2 mixture were carried out under multiple AC discharge breakdowns by using a needle-to-plate electrode configuration. The compositions of the gas mixture before and after breakdowns were detected by using a gas chromatography-mass spectrometer. The results show that a trace amount of C3HF7 exists in the C4F7N product; the decomposition of the C4F7N/CO2 mixture mainly produces CO, CF4 , CO As the number of breakdowns increases, the content of most decomposition products increases significantly, while the content of C3HF7 decreases. The possible formation pathways of the decomposition products were determined, and the corresponding reaction enthalpies were calculated by quantum chemistry calculation. Relevant results not only reveal the decomposition characteristics of C4F7N/CO2 under AC breakdowns but also help us to better understand the corresponding physicochemical mechanisms, which will provide a good reference for stable operation and safe maintenance in applications.
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Perfluorooctanoic acid (PFOA), a manufactured perfluorochemical is a common surfactant and environmental pollutant found in various consumer products and water sources. Epidemiological studies have demonstrated its association with kidney dysfunction. However, the mechanisms that trigger kidney dysfunction following PFOA exposure is a gap in the field. The work presented explores the potential epigenetic indicators of kidney disease due to exposure to PFOA. In this study, 30 days old CD-1 mice were exposed to 1, 5, 10, or 20 mg/kg/day of PFOA for 10 days. Following acute oral exposure, epigenetic alterations and expression levels of various markers of fibroblast activation were evaluated in kidney tissues. We noted that PFOA-exposed mice exhibited differential methylation yielding 879 differentially methylated regions compared to vehicle. The mRNA expression revealed significant increase in Dnmt1 with decreased Rasal1 expression at higher levels of PFOA exposure suggestive of Rasal1 hypermethylation (an early indicator of fibroblast activation in kidney). Like Dnmt1, we also observed significant increase in Hdac1, 3 and 4. These are class I & II HDACs which are known to be critically altered in some renal diseases. Further, the mRNA expression levels of TGF-β and α-SMA significantly increased compared to vehicle. The KEGG and Go enrichment pathway analysis of reduced representation bisulfite data also revealed pathways implicated in renal fibrosis. Our study shows clear evidence of epigenetic alterations (DNA methylation and HDAC expression changes) in tissues from mouse kidney following PFOA exposure. Our results also suggest that epigenetic alterations in kidney promote the expression of early markers of fibroblast activation.
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Per- and polyfluoroalkyl substances (PFASs) have come under increased scrutiny due to concerns about their potential toxicity and prevalence in the environment, particularly drinking water. PFASs are difficult to remove in full-scale water treatment systems because of their physicochemical properties. Here we evaluated the effectiveness of point-of-use (POU) and point-of-entry (POE) residential drinking water filters in removing a suite of three perfluoroalkyl sulfonic acids, seven perfluoroalkyl carboxylic acids, and six per- and polyfluoroalkyl ether acids in homes in central (n = 61) and southeastern (n = 12) North Carolina. POU systems included countertop and pitcher filters, faucet-mounted filters, activated carbon block refrigerator filters, activated carbon block under-sink filters, under-sink dual-stage filters, and under-sink reverse osmosis filters. All under-sink dual-stage and reverse osmosis filters tested showed near complete removal for all PFASs evaluated. In contrast, all other filters containing activated carbon exhibited variable PFAS removal. In these filters, PFAS removal efficiency was dependent on chain length, with long-chain PFASs (∼60–70% removal) being more efficiently removed than short-chain PFASs (∼40% removal). A few whole-house activated carbon POE systems (n = 8) were also evaluated; however, results were variable, and in some cases (four of eight systems), increased PFAS levels were observed in the filtered water.
Article
Perfluorinated alkyl substances (PFASs) persist and are ubiquitous in the environment. The origins of PFAS toxicity and how they specifically affect the functions of proteins remain unclear. Herein, we report that PFASs can strongly inhibit the activity of human carbonic anhydrases (hCAs), which are ubiquitous enzymes that catalyze the hydration of CO2, are abundant in the blood and organs of mammals, and involved in pH regulation, ion homeostasis and biosynthesis. The interactions between PFASs and hCAs were investigated using stopped-flow kinetic enzyme-inhibition measurements, native mass spectrometry (MS) and ligand-docking simulations. Narrow-bore emitters in native MS with inner diameters of ~300 nm were used to directly and simultaneously measure the dissociation constants of eleven PFASs to an enzyme, which was not possible using conventional emitters. The data from native MS and stopped-flow measurements were in excellent agreement. Of fifteen PFASs investigated, nine can inhibit at least one of four hCA isozymes (I, II, IX and XII) with sub-micromolar inhibition constants, including perfluorooctanoic acid (PFOA), perfluorooctanesulfonamide (PFOSA) and perfluorooctanesulfonic acid (PFOS). Some PFASs including those with both short and long perfluoromethylene chains can effectively inhibit at least one hCA isozyme with low-nM inhibition constants.
Article
Studies of firefighters have shown increased exposures to carcinogenic compounds and elevated rates of certain cancers compared to the general population, yet this research has focused almost exclusively on men. To address this gap, the Women Firefighters Biomonitoring Collaborative created a biological sample archive and analyzed levels of perfluoroalkyl substances (PFAS) among women firefighters (N = 86) and office workers (N = 84) in San Francisco. Serum samples were collected and analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to measure and compare PFAS levels between firefighters and office workers. 7 of 12 PFAS congeners were detected in the least 70% of the study population, and 4 congeners were detected in 100% of participants. In regression models comparing PFAS levels by occupation and adjusting for potential confounders, firefighters had higher geometric mean concentrations of PFAS compared to office workers PFHxS (2.22 (95% CI = 1.55, 3.18)), PFUnDA (1.83 (95% CI = 0.97, 3.45)), and PFNA (1.26 (95% CI = 1.01, 1.58)). Among firefighters, occupational position predicted exposure-firefighters and officers had higher PFNA, PFOA, PFDA, and PFUnDA levels compared to drivers. Women firefighters are exposed to higher levels of some PFAS compared to office workers, suggesting that some of these exposures may be occupationally related.
Article
Per- and polyfluoroalkyl substances (PFAS) are a class of artificially synthetic organic compounds that are hardly degraded in the natural environment. PFAS have been widely used for many decades, and the persistence and potential toxicity of PFAS are an emerging concern in the world. PFAS exposed via diet can be readily absorbed by the intestine and enter the circulatory system or accumulate directly at intestinal sites, which could interact with the intestine and cause the destruction of intestinal barrier. This review summarizes current relationships between PFAS exposure and intestinal barrier damage with a focus on more recent toxicological studies. Exposure to PFAS could cause inflammation in the gut, destruction of the gut epithelium and tight junction structure, reduction of the mucus layer, and induction of the toxicity of immune cells. PFAS accumulation could also induce microbial disorders and metabolic products changes. In addition, there are limited studies currently, and most available studies converge on the health risk of PFAS exposure for human intestinal disease. Therefore, more efforts are deserved to further understand potential associations between PFAS exposure and intestinal dysfunction and enable better assessment of exposomic toxicology and health risks for humans in the future.
Article
Perfluorooctane sulfonate (PFOS) has been widely used as a surface coating for household products. It still exists in living environments despite being restricted, due to its bioaccumulation and long half-life. Studies have shown that PFOS has the ability to induce adipogenic differentiation of human cells. Human mesenchymal stem cells (hMSCs) distributed within the adipose tissue might be a potential target of accumulated PFOS. However, traditional end-point toxicity assays failed to examine the subtle changes of cellular function exposed to low-dose persistent organic pollutants in real time. In the present work, highly sensitive and long-retained (more than 30 days) fluorescence based polymeric nanosensors were developed and employed for real-time assessment of cellular functions. hMSCs were engineered with sensor molecules encapsulated poly (lactic-co-glycolic acid) (PLGA) particles. Once internalized by hMSCs, PLGA particles continuously release and replenish sensor molecules to cytoplasm, resulting in prolonged fluorescence signal against photo bleaching and dilution by exocytosis. With this method, the dynamic changes of viability, ROS induction, and adipogenic differentiation related mRNA expression of hMSCs were monitored. PFOS with the concentration as low as 0.1 μM can induce cellular ROS and enhance the PPARγ and ap2 mRNA expression, suggesting the effect on promoting adipogenic differentiation of hMSCs.
Chapter
From the past two decades, perfluorooctanesulfonate (PFOS) has been the mostly studied chemical of PFC family, due to its widespread occurrence at global level. The occurrence of PFOS in different environmental media such as surface water, wastewater, sludge/biosolids, groundwater, human and other biota raised concerns about potential hazards to human. Combining various research studies on various aspects of PFOS, this review study summarized worldwide occurrence, fate and transport of PFOS in different environmental media along with the removal technologies for its remediation. With upgrading methods of detection, several countries provided guidelines for PFOS considering human health. It was observed that the natural surface water has higher concentration of PFOS in developed and more industrialized countries than that of developing/undeveloped one. Its occurrence in WWTP effluents indicates the inability of conventional biological treatments toward PFOS removal. PFOS in drinking water became a major route of exposure to human and other animals. Various advanced processes like physical adsorption, membrane filtration and several redox processes showed promising potential toward PFOS removal efficiency. The future challenge is to minimize the cost and increasing the efficiency of these methods. From the literature reviewed, knowledge gaps are identified, and future directions are provided accordingly.
Chapter
The occurrence of per- and polyfluoroalkyl substances (PFAS) in drinking water and their fate in treatment processes have been reviewed. These are environmentally persistent emerging contaminants that have been used in many applications since the 1950s. The industrial wastewater discharges and use of PFAS in fire-fighting foams are some of the major reasons for water contamination. PFAS are highly fluorinated aliphatic substances that are recalcitrant to conventional drinking water treatment technologies, which include coagulation, flocculation, sedimentation, sand filtration, oxidation (chlorination, ozonation), UV irradiation, and low-pressure membrane systems. However, activated carbon, anion exchange resins, and high-pressure membrane systems have shown significant removal of PFAS. The fate of PFAS in the drinking water treatment process is mainly influenced by their hydrophilic/hydrophobic nature, carbon-chain length, and functional groups. The data and literature reports were used to identify research gaps and make recommendations for future potential research.
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Wyeth-14,643 (WY) and ammonium perfluorooctanoate (C8) belong to a diverse class of compounds which have been shown to produce hepatic peroxisome proliferation in rodents. From previous work, WY, but not C8, has been shown to produce hepatocellular carcinoma in rats, while C8 has been shown to produce Leydig cell adenomas. In addition, based on a review of bioassay data a relationship appears to exist between peroxisome-proliferating compounds and Leydig cell adenoma and pancreatic acinar cell hyperplasia/adenocarcinoma formation. To further investigate the relationship between peroxisome-proliferating compounds and hepatic, Leydig cell, and pancreatic acinar cell tumorigenesis, a 2-year feeding study in male CD rats was initiated to test the hypothesis that peroxisome proliferating compounds induce a tumor triad (liver, Leydig cell, pancreatic acinar cell), and to examine the potential mechanism for the Leydig cell tumors. The study was conducted using 50 ppm WY and 300 ppm C8. The concentration of WY in the diet was decreased to 25 ppm on test day 301 due to increased mortality. In addition to the ad libitum control, a second control was pair-fed to the C8 group. Interim sacrifices were performed at 1- or 3-month intervals. Peroxisome proliferation measured by beta-oxidation activity and cell proliferation were measured in the liver and testis at all time points and in the pancreas beginning at the 9-month time point (cell proliferation only). Serum hormone concentrations (estradiol, testosterone, LH, FSH, and prolactin) were also measured at each time point. Increased relative liver weights and hepatic beta-oxidation activity were observed in both the WY- and C8-treated rats at all time points. In contrast, hepatic cell proliferation was significantly increased only in the WY-treated group. Neither WY nor C8 significantly altered the rate of Leydig cell beta-oxidation or Leydig cell proliferation when compared to the control groups. Moreover, the basal rate of beta-oxidation in Leydig cells was approximately 20 times less than the rate of hepatic beta-oxidation. There were no biologically meaningful differences in serum testosterone, FSH, prolactin, or LH concentrations in the WY- and C8-treated rats when compared to their respective controls. There were, however, significant increases in serum estradiol concentrations in the WY- and C8-treated rats at 1, 3, 6, 9, 15, 18, and 21 months. At 12 months, only the C8-treated rats had elevated serum estradiol concentrations when compared to the pair-fed control. Histopathological evaluation revealed compound-related increases in liver, Leydig cell, and pancreatic acinar cell tumors in both WY- and C8-treated rats. The data support the hypothesis that the peroxisome-proliferating compounds induce the previously described tumor triad. In addition, both C8 and WY produced a sustained increase in serum estradiol concentrations that correlated with the potency of the 2 compounds to induce Leydig cell tumors (i.e., WY caused a more consistent sustained increase in serum estradiol throughout the entire study, and more specifically at the end of the study, than did C8). This study suggests that estradiol may play a role in enhancement of Leydig cell tumors in the rat, and that peroxisome proliferators may induce tumors via a non-LH type mechanism.
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Perfluoroalkyls (PFAs) and polybrominated diphenyl ethers (PBDEs) are two classes of emerging persistent organic pollutants (POPs) that are widely used in domestic and workplace products. These compounds also occur in remote locations such as the Arctic where they are accumulated in the food chain. This study makes connections between indoor sources of these chemicals and the potential and mode for their transport in air. In the case of the PFAs, three perfluoralkyl sulfonamides (PFASs) were investigated--N-methyl perfluorooctane sulfonamidoethanol (MeFOSE), N-ethyl perfluorooctane sulfonamidoethanol (EtFOSE), and N-methyl perfluorooctane sulfonamidethylacrylate (MeFOSEA). These are believed to act as precursors that eventually degrade to perfluorooctane sulfonate (PFOS), which is detected in samples from remote regions. High-volume samples were collected for indoor and outdoor air to investigate the source signature and strength. Mean indoor air concentrations (pg/m3) were 2590 (MeFOSE), 770 (EtFOSE), and 630 (sigmaPBDE). The ratios of concentration between indoor and outdoor air were 110 for MeFOSE, 85 for EtFOSE, and 15 for sigmaPBDE. The gas and particle phases were collected separately to investigate the partitioning characteristics of these chemicals. Measured particulate percentages were compared to predicted values determined using models based on the octanol-air partition coefficient (K(OA)) and supercooled liquid vapor pressure (pL(o)); these models were previously developed for nonpolar, hydrophobic chemicals. To make this comparison for the three PFASs, it was necessary to measure their K(OA) and vapor pressure. K(OA) values were measured as a function of temperature (0 to +20 degrees C). Values of log K(OA) at 20 degrees C were 7.70, 7.78, and 7.87 for MeFOSE, EtFOSE, and MeFOSEA, respectively. Partitioning to octanol increased at colder temperatures, and the enthalpies associated with octanol-air transfer (deltaH(OA), kJ/mol) were 68-73 and consistent with previous measurements for nonpolar hydrophobic chemicals. Solid-phase vapor pressures (pS(o)) were measured at room temperature (23 degrees C) by the gas saturation method. Values of pS(o) (Pa) were 4.0 x 10(-4), 1.7 x 10(-3), and 4.1 x 10(-4), respectively. These were converted to pL(o) for describing particle-gas exchange. Both the pL(o)-based model and the K(OA) model worked well for the PBDEs but were not valid for the PFASs, greatly underpredicting particulate percentages. These results suggest that existing K(OA)- and pL(o)-based models of partitioning will need to be recalibrated for PFASs.
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The purpose of this investigation was to determine whether there has been a change in the human blood concentration of perfluorooctanesulfonate (PFOS), perfluorooctanoate (PFOA), and five other fluorochemicals since 1974. Blood samples were collected in 1974 (serum) and 1989 (plasma) from volunteer participants of a large community health study. The study included a total of 356 samples (178 from each time period). These samples were analyzed by high-pressure liquid chromatography/tandem mass spectrometry methods. The median 1974 and 1989 fluorochemical concentrations, respectively, were as follows: PFOS, 29.5 ng/mL vs. 34.7 ng/mL; PFOA, 2.3 ng/mL vs. 5.6 ng/mL; perfluorohexanesulfonate (PFHS), 1.6 ng/mL vs. 2.4 ng/mL; and N-ethyl perfluorooctanesulfonamidoacetate (PFOSAA), less than the lower limit of quantitation (LLOQ; 1.6 ng/mL, vs. 3.4 ng/mL). For N-methyl perfluorooctanesulfonamidoacetate (M570), perfluorooctanesulfonamide, and perfluorooctanesulfonamidoacetate, median serum concentrations in both years were less than the LLOQ values (1.0, 1.0, and 2.5 ng/mL, respectively). Statistical analysis of 58 paired samples indicated that serum concentrations of PFOS, PFOSAA, PFOA, PFHS, and M570 were significantly (p < 0.001) higher in 1989 than in 1974. The data from 1989 were then compared with geometric mean fluorochemical concentrations of serum samples collected in 2001 from 108 American Red Cross adult blood donors from the same region. Except for M570, there were no statistically significant (p < 0.05) geometric mean fluorochemical concentration differences between the 1989 and 2001 samples. In conclusion, based on this study population, PFOS and other serum fluorochemical concentrations have increased between 1974 and 1989. Comparison with other regional data collected in 2001 did not suggest a continued increase in concentrations since 1989.
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In a recent study of 198 Swedish children with persistent allergic symptoms and 202 controls without such symptoms, we reported associations between the symptoms and the concentrations of n-butyl benzyl phthalate (BBzP) and di(2-ethylhexyl) phthalate (DEHP) in dust taken from the childrens' bedrooms. In the present study we examined associations between the concentrations of different phthalate esters in the dust from these bedrooms and various characteristics of the home. The study focused on BBzP and DEHP because these were the phthalates associated with health complaints. Associations have been examined using parametric and nonparametric tests as well as multiple logistic regression. For both BBzP and DEHP, we found associations between their dust concentrations and the amount of polyvinyl chloride (PVC) used as flooring and wall material in the home. Furthermore, high concentrations of BBzP (above median) were associated with self-reported water leakage in the home, and high concentrations of DEHP were associated with buildings constructed before 1960. Other associations, as well as absence of associations, are reported. Both BBzP and DEHP were found in buildings with neither PVC flooring nor wall covering, consistent with the numerous additional plasticized materials that are anticipated to be present in a typical home. The building characteristics examined in this study cannot serve as complete proxies for these quite varied sources. However, the associations reported here can help identify homes where phthalate concentrations are likely to be elevated and can aid in developing mitigation strategies.
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Polybrominated diphenyl ethers (PBDEs) have been measured for the first time in three different indoor dust Standard Reference Materials (SRMs) prepared by the National Institute of Standards and Technology (NIST). Two of these, SRM 2583 (Trace Elements in Indoor Dust) and SRM 2584 (Trace Elements in Indoor Dust), have been certified previously for lead and other inorganic constituents. A third, SRM 2585 (Organics in Indoor Dust), is a new indoor dust reference material prepared by NIST which will be certified for various organic compounds (polycyclic aromatic hydrocarbons, pesticides and polychlorinated biphenyls) in 2005 including certified concentrations for 16 individual PBDE congeners and reference values for an additional three PBDE congeners. Dust SRMs were analyzed for 30 PBDE congeners using high-resolution gas chromatography combined with low-resolution mass spectrometry operated in both negative chemical ionization (GC/ECNI-MS) and electron impact ionization (GC/EI-MS) modes. Sensitivity was an order of magnitude higher using GC/ECNI-MS relative to GC/EI-MS. These SRMs have been characterized and compared to the three PBDE commercial products (pentaBDE, octaBDE and decaBDE). PentaBDE and DecaBDE were present in all three SRMs and were the dominant commercial products, making up approximately 33% and 58%, respectively. Recent studies suggest that house dust may be a leading source of human exposure to PBDEs. These SRMs are the first reference materials with certified concentrations for PBDEs, which will aid in validating future measurements of PBDEs in house dust and other similar matrices.
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In this paper recent results are provided of an investigation on the discovery of 12 perfluorinated surfactants (PS) in different surface and drinking waters (Skutlarek et al. 2006 a, Skutlarek et al. 2006 b). In the last years, many studies have reported ubiquitous distribution of this group of perfluorinated chemicals, especially perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in the environment, particularly in wildlife animal and human samples (Giesy and Kannan 2001, Houde et al. 2006, Prevedouros et al. 2006). Perfluorinated surfactants (e.g. PFOS and PFOA) have shown different potentials for reproductory interference and carcinogenity in animal experiments as well as partly long half-lives in humans (Guruge et al. 2006, FSA UK 2006a, FSA UK 2006b, 3M 2005, OECD 2002, Yao and Zhong 2005). They possess compound-dependent extreme recalcitrance against microbiological and chemical degradation and, in addition, they show variable potentials for bioaccumulation in animals and humans (Houde et al. 2006). Surface and drinking water samples were collected from different sampling sites: Surface waters: samples taken from the rivers Rhine, Ruhr, Moehne and some of their tributaries. Further samples were taken from the Rhine-Herne-Canal and the Wesel-Datteln-Canal. Drinking waters: samples taken in public buildings of the Rhine-Ruhr area. After sample clean-up and concentration by solid-phase extraction, the perfluorinated surfactants were determined using HPLC-MS/MS. All measured concentrations (sum of seven mainly detected components) in the Rhine river and its main tributaries (mouths) were determined below 100 ng/L. The Ruhr river (tributary of the Rhine) showed the highest concentration (94 ng/L), but with a completely different pattern of components (PFOA as major component), as compared with the other tributaries and the Rhine river. Further investigations along the Ruhr river showed remarkably high concentrations of PS in the upper reaches of the Ruhr river and the Moehne river (tributary of the Ruhr) (Ruhr: up to 446 ng/L, Moehne: up to 4385 ng/L). The maximum concentration of all drinking water samples taken in the Rhine-Ruhr area was determined at 598 ng/L with the major component PFOA (519 ng/L). The surface water contaminations most likely stem from contaminated inorganic and organic waste materials (so-called 'Abfallgemisch'). This waste material was legally applied to several agricultural areas on the upper reaches of the Moehne. Perfluorinated surfactants could be detected in some suchlike soil samples. They contaminated the river and the reservoir belonging to it, likely by superficial run-off over several months or probably years. Downstream, dilution effects are held responsible for decreasing concentrations of PS in surface waters of the Moehne and the Ruhr river. In analogy to the surface water samples, PS (major component PFOA) can be determined in many drinking water samples of the Rhine-Ruhr area where the water supplies are mainly based on bank filtration and artificial recharge. The concentrations found in drinking waters decreased with the concentrations of the corresponding raw water samples along the flow direction of the Ruhr river (from east to west) and were not significantly different from surface water concentrations. This indicates that perfluorinated surfactants are at present not successfully removed by water treatment steps. Because of their different problematic properties (persistence, mobility, toxicity, bioaccumulation), the concentrations of specific perfluorinated surfactants and their precursors in drinking waters and food have to be minimised. Therefore, it is of utmost importance to take the initiative to establish suitable legal regulations (limitations/ban) concerning the production and use of these surfactants and their precursors. Furthermore, it is indispensable to protect water resources from these compounds. A discussion on appropriate limit values in drinking water and foodstuffs is urgently needed. Concerning the assumed soil contamination, the corresponding regulation (Bioabfall-Verordnung 1998--Regulation on Organic Waste 1998) should be extended to allow the control of relevant organic pollutants.
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Only limited data exist on lactation as an exposure source of persistent perfluorinated chemicals (PFCs) for children. We studied occurrence and levels of PFCs in human milk in relation to maternal serum together with the temporal trend in milk levels between 1996 and 2004 in Sweden. Matched, individual human milk and serum samples from 12 primiparous women in Sweden were analyzed together with composite milk samples (25-90 women/year) from 1996 to 2004. Eight PFCs were detected in the serum samples, and five of them were also above the detection limits in the milk samples. Perfluorooctanesulfonate (PFOS) and perfluorohexanesulfonate (PFHxS) were detected in all milk samples at mean concentrations of 0.201 ng/mL and 0.085 ng/mL, respectively. Perfluorooctanesulfonamide (PFOSA), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) were detected less frequently. The total PFC concentration in maternal serum was 32 ng/mL, and the corresponding milk concentration was 0.34 ng/mL. The PFOS milk level was on average 1% of the corresponding serum level. There was a strong association between increasing serum concentration and increasing milk concentration for PFOS (r(2) = 0.7) and PFHxS (r(2) = 0.8). PFOS and PFHxS levels in composite milk samples were relatively unchanged between 1996 and 2004, with a total variation of 20 and 32% coefficient of variation, respectively. The calculated total amount of PFCs transferred by lactation to a breast-fed infant in this study was approximately 200 ng/day. Lactation is a considerable source of exposure for infants, and reference concentrations for hazard assessments are needed.
Article
The exposure of humans to perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) was quantified with emphasis on assessing the relative importance of metabolic transformation of precursor compounds. A Scenario-Based Risk Assessment (SceBRA) approach was used to model the exposure to these compounds from a variety of different pathways, the uptake into the human body and resulting daily doses. To capture the physiological and behavioral differences of age and gender, the exposure and resulting doses for seven consumer groups were calculated. The estimated chronic doses of a general population of an industrialized country range from 3.9 to 520 ng/(kg day) and 0.3 to 140 ng/(kg day) for PFOS and PFOA, respectively. The relative importance of precursor-based doses of PFOS and PFOA was estimated to be 2-5% and 2-8% in an intermediate scenario and 60-80% and 28-55% in a high-exposure scenario. This indicates that sub groups of the population may receive a substantial part of the PFOS and PFOA doses from precursor compounds, even though they are of low importance for the general population. Similar to a preceding study, uptake of perfluorinated acids from contaminated food and drinking water was identified as the most important pathway of exposure for the general population. The biotransformation yields of telomer-based precursors and to a lesser extent perfluorooctanesulfonylfluoride-based precursors were identified as influential parameters in the uncertainty analysis. Fast food consumption and fraction of food packaging paper treated with PFCs were influential parameters for determining the doses of PFOA.
Article
Perfluorinated fatty acids (PFFAs), such as perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA), are known peroxisome proliferators and hepatocarcinogens. A causal link between an increase in the oxidative stress by peroxisomes and tumor promotion has been proposed to explain the hepatocarcinogenicity of PFOA and PFDA. However, the down-regulation of gap junctional intercellular communication (GJIC) has also been linked to the tumor-promoting properties of many carcinogens. Therefore, the effect of PFFAs on GJIC in WB-rat liver epithelial cells was determined. The chain length of the PFFAs tested for an effect on GJIC ranged from 2 to 10, 16 and 18 carbons. Carbon lengths of 7 to 10 inhibited GJIC in a dose-response fashion, whereas carbon lengths of 2 to 5, 16 and 18 did not appreciably inhibit GJIC. Inhibition occurred within 15 min and was reversible, with total recovery from inhibition occurring within 30 min after the removal of the compound from the growth medium. This short time of inhibition suggests that GJIC was modified at the post-translational level. Also, this short time period was not long enough for peroxisome proliferation. The post-translational modification of the gap junction proteins was not a consequence of altered phosphorylation as determined by Western blot analysis. Perfluorooctanesulfonic acid also inhibited GJIC in a dose-response fashion similar to PFDA, indicating that the determining factor of inhibition was probably the fluorinated tail, which required 7-10 carbons. Our results suggest that PFFAs could potentially act as hepatocarcinogens at the level of gap junctions in addition to or instead of through peroxisome proliferation.
Article
Compounds that cause peroxisome proliferation in rats and mice have been reported to interfere with mitochondrial (mt) bioenergetics and possibly biogenesis. The purpose of this investigation was to establish whether proliferation of peroxisomes and mitochondria are necessarily related. Perfluorooctanesulfonate (PFOS) and N-ethyl perfluorooctanesulfonamido ethanol (N-EtFOSE) were investigated as peroxisome proliferators in comparison to perfluorooctanoic acid (PFOA). Three parameters were chosen to assess peroxisome proliferation, stimulation of lauroyl CoA oxidase activity, reduction of serum cholesterol concentration, and hepatomegaly. mt Biogenesis was assessed through cytochrome oxidase activity, cytochrome content and mitochondrial DNA (mtDNA) copy number. PFOA, PFOS, or N-EtFOSE was administered via a single i.p. injection at 100 mg/kg in male rats, and measurements were made 3 days later. In this model, PFOS and PFOA share similar potencies as peroxisome proliferators, whereas N-EtFOSE showed no activity. mt Endpoints were altered only in the PFOA treatment group, which consisted of a decrease cytochrome oxidase activity in liver tissue and an increase in the mtDNA copy number. None of the perfluorooctanoates significantly altered mt cytochrome content following acute in vivo treatment. These data demonstrate that acute administration of PFOS or PFOA causes hepatic peroxisome proliferation in rats. However, stimulation of mt biogenesis is not a characteristic response of all peroxisome proliferators.
Article
Perfluorinated acids (PFAs) recently have emerged as persistent global contaminants after their detection in wildlife and humans from various geographic locations. The highest concentrations of perfluorooctane sulfonate are characteristically observed in high trophic level organisms, indicating that PFAs may have a significant bioaccumulation potential. To examine this phenomenon quantitatively, we exposed juvenile rainbow trout (Oncorhynchus mykiss) simultaneously to a homologous series of perfluoroalkyl carboxylates and sulfonates for 34 d in the diet, followed by a 41-d depuration period. Carcass and liver concentrations were determined by using liquid chromatography-tandem mass spectrometry, and kinetic rates were calculated to determine compound-specific bioaccumulation parameters. Depuration rate constants ranged from 0.02 to 0.23/d, and decreased as the length of the fluorinated chain increased. Assimilation efficiency was greater than 50% for all test compounds, indicating efficient absorption from food. Bioaccumulation factors (BAFs) ranged from 0.038 to 1.0 and increased with length of the perfluorinated chain; however, BAFs were not statistically greater than 1 for any PFA. Sulfonates bioaccumulated to a greater extent than carboxylates of equivalent perfluoroalkyl chain length, indicating that hydrophobicity is not the sole determinant of PFA accumulation potential and that the acid function must be considered. Dietary exposure will not result in biomagnification of PFAs in juvenile trout, but extrapolation of these bioaccumulation parameters to larger fish and homeothermic organisms should not be performed.
Article
Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are shown to be globally distributed, environmentally persistent and bioaccumulative. Although there is evidence that these compounds exist in the serum of non-occupationally exposed humans, the pathways leading to the presence of PFOS and PFOA are not well characterized. The concentrations of PFOS and PFOA in the vacuum cleaner dust collected in Japanese homes were measured. The compounds were detected in all the dust samples and the ranges were 11-2500 ng g(-1) for PFOS and 69-3700 ng g(-1) for PFOA. It was ascertained that PFOS and PFOA were present in the dust in homes, and that the absorption of the dust could be one of the exposure pathways of the PFOS and PFOA to humans. With regard to risk management, it is important to consider the usage of PFOS and PFOA in the indoor environment in order to avoid further pollution.
Article
Perfluoroalkyl acids such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) have applications in numerous industrial and consumer products. Although the toxicology of some of these compounds has been investigated in the past, the widespread prevalence of PFOS and PFOA in humans, as demonstrated in recent bio-monitoring studies, has drawn considerable interest from the public and regulatory agencies as well as renewed efforts to better understand the hazards that may be inherent in these compounds. This review provides a brief overview of the perfluoroalkyl chemicals and a summary of the available information on the developmental toxicity of the eight-carbon compounds, PFOS and PFOA. Although the teratological potentials of some of these chemicals had been studied in the past and the findings were generally unremarkable, results from recent postnatal studies on developmental and reproductive indices have prompted consideration of their relevance to human health risk. Based on current understanding of the developmental effects of PFOS and PFOA in rodents, several avenues of research are suggested that would further support the risk assessment of these perfluorinated organic chemicals.
Article
Perfluorocarboxylic acids (PFCAs) are persistent chemicals that have been found widely in the environment. Their accurate determination in environmental matrixes, particularly soil, sediment, and sludge, at low levels presents significant analytical challenges. The commercialization of electrospray interfaces for liquid chromatography-mass spectrometric analysis facilitated analysis of PFCAs at low levels, but issues with quantitative analysis due to matrix suppression or enhancement still persist. The methods described in this study utilize simple and rapid sample purification procedures to remove matrix components sufficiently so that errors due to coeluting matrix peaks are negligible and recoveries of PFCAs are consistently and reproducibly quantitative. Extracts from solid samples (soil and sediment) and liquid bacterial sludge are purified using dispersive solid-phase extraction. Recovery values generally are in the 70-120% range, with limits of quantitation of 1 ppb. The method utilizes an extraction solvent previously shown to release and recover aged residues of PFCAs. A confirmatory method using two precursor to product ions is also provided and demonstrated.
Article
Polybrominated diphenyl ethers (PBDEs) are widely used as additive flame retardants in plastics, soft furnishings, electrical and electronic equipment, and insulation in the indoor environment, and may be released indoors via volatilization or as dusts. The penta-and octa-brominated mixes are now banned in most parts of Europe, and phasing out of their use has recently begun in North America. This study follows a previous investigation into indoor air levels of PBDEs. House dust was analyzed from the family vacuum cleaners of 68 of the same 74 randomly selected homes, in Ottawa, Canada during the winter of 2002-2003. PBDEs, comprising on average 42% BDE-209, were found in all samples. The levels were log-normally distributed with a geometric mean sigmaPBDE of 2000 ng g(-1), and a median of 1800 ng g(-1) dust. The levels in dust did not correlate with questionnaire information on house characteristics. Correlations were found between pentamix congener levels in dust and in air from the same homes, but not for congeners of the more highly brominated mixes. Exposure scenarios are presented for mean and high dust ingestion rates, and compared against exposures from other pathways, for both adults and toddlers (6 months-2 years). Assuming a mean dust ingestion rate and median dust and air concentrations, adults would be exposed to ca. 7.5 ng sigmaPBDE d(-1) via the dust ingestion pathway, which represents approximately 14% of total daily exposure when compared to diet (82%) and inhalation (4%). However, for toddlers the equivalent intakes would be 99 ng d(-1), representing 80% of their daily PBDE exposure. At high dust ingestion rates these values increase to 180 ng d(-1) (80% daily intake) for adults and 360 ng d(-1) (89% daily intake) for toddlers. The data give a clearer picture of sources of PBDE exposure in the home environment and suggest that dust could be a significant exposure pathway for some individuals, particularly children.
Article
A series of perfluorinated compounds (PFCs) including perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) have been recently measured in a variety of environmental samples and biological matrices. In order to better understand the human exposure routes of these chemicals, levels of PFOS, PFOA, perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHS) and perfluorooctane sulfonamide (PFOSA) in house dust samples were investigated. The data revealed a correlation between the concentrations of PFCs and the percentage of carpeting in the house; older houses tended to have less carpeting, hence lower levels of these perfluorinated compounds in their dust.
Article
This review describes the sources, fate, and transport of perfluorocarboxylates (PFCAs) in the environment, with a specific focus on perfluorooctanoate (PFO). The global historical industry-wide emissions of total PFCAs from direct (manufacture, use, consumer products) and indirect (PFCA impurities and/or precursors) sources were estimated to be 3200-7300 tonnes. It was estimated that the majority (approximately 80%) of PFCAs have been released to the environment from fluoropolymer manufacture and use. Although indirect sources were estimated to be much less importantthan direct sources, there were larger uncertainties associated with the calculations for indirect sources. The physical-chemical properties of PFO (negligible vapor pressure, high solubility in water, and moderate sorption to solids) suggested that PFO would accumulate in surface waters. Estimated mass inventories of PFO in various environmental compartments confirmed that surface waters, especially oceans, contain the majority of PFO. The only environmental sinks for PFO were identified to be sediment burial and transport to the deep oceans, implying a long environmental residence time. Transport pathways for PFCAs in the environment were reviewed, and it was concluded that, in addition to atmospheric transport/degradation of precursors, atmospheric and ocean water transport of the PFCAs themselves could significantly contribute to their long-range transport. It was estimated that 2-12 tonnes/ year of PFO are transported to the Artic by oceanic transport, which is greater than the amount estimated to result from atmospheric transport/degradation of precursors.
Article
Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in air (using PUF disk passive samplers) in 31 homes, 33 offices, 25 cars, and 3 public microenvironments. Average concentrations of sigmaBDE (273 pg m(-3)) and sigmaPCB (8920 pg m(-3)) were an order of magnitude higher than those previously reported for outdoor air. Cars were the most contaminated microenvironment for sigmaBDE (average = 709 pg m(-3)), but the least for sigmaPCB (average = 1391 pg m(-3)). Comparison with data from a previous spatially consistent study, revealed no significant decline in concentrations of sigmaPCB in indoor air since 1997-98. Concentrations in indoor dust from 8 homes were on average 215.2 ng sigmaBDE g(-1), slightly higher than other European dust samples, but twenty times lower than Canadian samples. Inhalation makes an important contribution (between 4.2 and 63% for adults) to overall UK exposure to sigmaPCB. For sigmaBDE, dust ingestion makes a significant but--in contrast to Canada-a not overwhelming contribution (up to 37% for adults, and 69% for toddlers). Comparison of UK and Canadian estimates of absolute exposure to sigmaBDE suggest that differences in dust contamination are the likely cause of higher PBDE body burdens in North Americans compared to Europeans.
Article
Human exposure to perfluorinated compounds is a worldwide phenomenon; however, routes of human exposure to these compounds have not been well-characterized. Fifty-four solid food composite samples collected as part of the Canadian Total Diet Study (TDS) were analyzed for perfluorocarboxylates and perfluorooctanesulfonate (PFOS) using a methanol extraction liquid chromatography tandem mass spectrometry method. Foods analyzed included fish and seafood, meat, poultry, frozen entrées, fast food, and microwave popcorn collected from 1992 to 2004 and prepared as for consumption. Nine composites contained detectable levels of perfluorinated compounds-four meat-containing, three fish and shellfish, one fast food, and one microwave popcorn. PFOS and perfluorooctanoate (PFOA) were detected the most frequently; concentrations ranged from 0.5 to 4.5 ng/g. The average dietary intake of total perfluorocarboxylates and PFOS for Canadians was estimated to be 250 ng/day, using results from the 2004 TDS composites. A comparison with intakes of perfluorocarboxylates and PFOS via other routes (air, water, dust, treated carpeting, and apparel) suggested that diet is an important source of these compounds. There was a substantial margin of exposure between the toxicological points of reference and the magnitude of dietary intake of perfluorinated compounds for Canadians >/= 12 years old.
Article
Air samples were collected from 4 field sites in Europe: 2 sites from the UK, Hazelrigg (semi-rural) and Manchester (urban); 1 site from Ireland: Mace Head (rural); and 1 site from Norway: Kjeller (rural). Additionally, air samples were taken from indoor locations in Tromsø, Norway. Air samples were collected using high-volume air samplers employing sampling modules containing glass-fibre filters (GFFs, particle phase), and glass columns with a polyurethane foam (PUF)-XAD-2-PUF sandwich (gaseous phase). Typical outdoor air volumes required for the determination of per- and polyfluorinated alkyl substances (PFAS) ranged from 500-1800 m3. GFFs and PUF-XAD columns were analysed separately to obtain information on phase partitioning. All air samples were analysed for volatile, neutral PFAS, with selected GFF samples halved for analysis of both neutral and airborne particle-bound ionic PFAS. Volatile PFAS were extracted from air samples by cold-column immersion with ethyl acetate, and were analysed by gas chromatography-mass spectrometry in the positive chemical ionisation mode (GC-PCI-MS). Ionic PFAS were extracted from GFFs by sonication in methanol, and were analysed by liquid chromatography-time-of-flight-mass spectrometry (LC-TOF-MS) using electrospray ionisation in the negative ion mode (ESI-). Perfluorooctanoate (PFOA) was often the predominant analyte found in the particulate phase at concentrations ranging from 1-818 pg m(-3), and 8:2 fluorotelomer alcohol (FTOH) and 6:2 FTOH were the prevailing analytes found in the gas phase, at 5-243 pg m(-3) and 5-189 pg m(-3), respectively. These three PFAS were ubiquitous in air samples. Many other PFAS, both neutral and ionic, were also present, and levels of individual analytes were in the 1-125 pg m(-3) range. Levels of some PFAS exceeded those of traditional persistent organic pollutants (POPs). In this study, the presence of 12:2 FTOH and fluorotelomer olefins (FTolefins), and ionic PFAS other than perfluorooctane sulfonate (PFOS) and PFOA, are reported in air samples for the first time. Concentrations of neutral PFAS were several orders of magnitude higher in indoor air than outdoor air, making homes a likely important diffuse source of PFAS to the atmosphere. Our repeated findings of non-volatile ionic PFAS in air samples raises the possibility that they might directly undergo significant atmospheric transport on particles away from source regions, and more atmospheric measurements of ionic PFAS are strongly recommended.
Article
The aim of this study was to determine the dietary intake of perfluorinated chemicals (PFCs) by the population of Tarragona County (Catalonia, Spain). PFC levels were determined in 36 composite samples of foodstuffs randomly purchased in various locations. Exposure to PFCs through the diet was estimated for various age/gender groups. Perfluorooctane sulfonate (PFOS), perfluorocarboxylate perfluorooctanoate (PFOA), and perfluoroheptanoic acid (PFHpA) were the only detected PFCs in foodstuffs. On average, for a standard adult man (70 kg of body weight), the dietary intake of PFOS was estimated to be 62.5 or 74.2 ng/day (assuming ND=0 or ND=1/2 LOD, respectively). Fish, followed by dairy products and meats, were the main contributors to PFOS intake. For an adult man, the intake of PFOS (1.07 ng/kg/day) and those of PFOA and PFHpA were lower than that recently reported for Canada (4.0 ng/kg/day), and considerably lower than that previously found in the United Kingdom, the only two countries where, to date, results concerning this issue have been reported. A correlation between dietary intake and blood levels of PFOS is suggested. However, the current results do not justify dietary intake as the main route of exposure governing blood concentrations of other PFCs.
Article
The perfluoroalkyl acids (PFAAs), including perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), have come under increasing scrutiny due to their persistence, global distribution, and toxicity. Given that their human exposure routes remain poorly characterized, the potential role of house dust needs to be more completely evaluated. In this study, new methods for the analysis of 10 PFAAs and three fluorinated telomer alcohols (FTOHs) were developed for dust samples collected from homes (n = 102) and day care centers (n = 10) in Ohio and North Carolina in 2000-2001. FTOHs were measured by GC/ MS and PFAAs were analyzed by LC-MS/MS. PFOS and PFOA were the most prominent compounds detected, occurring in over 95% of the samples at median concentrations of 201 and 142 ng/g of dust, respectively. Maximal concentrations of PFOS were 12 100 ng/g (95th percentile, 2240 ng/g), PFOA 1960 ng/g (95th percentile, 1200 ng/g), and perfluorohexanesulfonate (PFHS) 35 700 ng/g (95th percentile, 2300 ng/g). The 8:2 FTOH, which is volatile and can degrade to PFOA, had a maximum concentration of 1660 ng/g dust (95th percentile, 669 ng/g). These results indicate that perfluorinated compounds are present in house dust at levels that may represent an important pathway for human exposure.
  • Upham B. L.
Uses of Perfluorinated Substances;Greenpeace Research Laboratories Technical Note 06
  • Greenpeace