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  • 1.
    Cousins, Ian
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Kong, Deguo
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Vestergren, Robin
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Reconciling measurement and modelling studies of the sources and fate of perfluorinated carboxylates2011In: Environmental Chemistry, ISSN 1448-2517, E-ISSN 1449-8979, Vol. 8, no 4, p. 339-354Article, review/survey (Refereed)
    Abstract [en]

    This study critically evaluates the recently published measurement and modelling studies of the sources and fate of perfluorinated carboxylates (PFCAs). It is concluded that modelling studies provide support to the 'direct hypothesis' for PFOA and PFNA (i.e. the global dominance of direct sources (mainly from fluoropolymer manufacturing)). Empirical evidence for the importance of direct sources of PFOA and PFNA is provided by PFNA : PFOA ratios and isomer profiles of PFOA in ocean water. However, homologue patterns of long-chain PFCAs in biota from remote regions suggest that indirect sources (mainly from precursor degradation) are proportionally more important for PFCAs with more than 10 carbons. Temporal data in biotic and abiotic media are reviewed and an increasing trend to 2000 is observed for all PFCAs, with discrepancies in time trends reported after that period. Some studies on temporal patterns report a levelling off or decline in the latter part of the 2000s for PFOA and PFNA, whereas others show a continual increase throughout the study period. Differences in temporal patterns result from the fact that some environments respond faster to emission changes than others and may thus be useful to elucidate the importance of direct and indirect sources to different regions.

  • 2.
    Cousins, Ian T.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Vestergren, Robin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Wang, Zhanyun
    Scheringer, Martin
    McLachlan, Michael S.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    The precautionary principle and chemicals management: The example of perfluoroalkyl acids in groundwater2016In: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 94, p. 331-340Article, review/survey (Refereed)
    Abstract [en]

    Already in the late 1990s microgram-per-liter levels of perfluorooctane sulfonate (PFOS) were measured in water samples from areas where fire-fighting foams were used or spilled. Despite these early warnings, the problems of groundwater, and thus drinking water, contaminated with perfluoroalkyl and polyfluoroalkyl substances (PFASs) including PFOS are only beginning to be addressed. It is clear that this PFAS contamination is poorly reversible and that the societal costs of clean-up will be high. This inability to reverse exposure in a reasonable timeframe is a major motivation for application of the precautionary principle in chemicals management. We conclude that exposure can be poorly reversible; 1) due to slow elimination kinetics in organisms, or 2) due to poorly reversible environmental contamination that leads to continuous exposure. In the second case, which is relevant for contaminated groundwater, the reversibility of exposure is not related to the magnitude of a chemical's bioaccumulation potential. We argue therefore that all PFASs entering groundwater, irrespective of their perfluoroalkyl chain length and bioaccumulation potential, will result in poorly reversible exposures and risks as well as further clean-up costs for society. To protect groundwater resources for future generations, society should consider a precautionary approach to chemicals management and prevent the use and release of highly persistent and mobile chemicals such as PFASs. (C) 2016 Elsevier Ltd. All rights reserved.

  • 3.
    Gomis Ferreira, Melissa I.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Vestergren, Robin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Nilsson, Helena
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Contribution of Direct and Indirect Exposure to Human Serum Concentrations of Perfluorooctanoic Acid in an Occupationally Exposed Group of Ski Waxers2016In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 50, no 13, p. 7037-7046Article in journal (Refereed)
    Abstract [en]

    The contribution of direct (i.e., uptake of perfluorooctanoic acid (PFOA) itself) and indirect (i.e., uptake of 8:2 fluorotelomer alcohol (FTOH) and metabolism to PFOA) exposure to PFOA serum concentrations was investigated using a dynamic one compartment pharmacokinetic (PK) model. The PK model was applied to six occupationally exposed ski waxers for whom direct and indirect exposures via inhalation were characterized using multiple measurements with personal air sampling devices. The model was able to predict the diverging individual temporal trends of PFOA in serum with correlation coefficients of 0.82-0.94. For the four technicians with high initial concentrations of PFOA in serum (250-1050 ng/mL), the ongoing occupational exposure (both direct and indirect) was of minor importance and net depuration of PFOA was observed throughout the ski season. An estimated average intrinsic elimination half-life of 2.4 years (1.8-3.1 years accounting for variation between technicians and model uncertainty) was derived for these technicians. The remaining two technicians, who had much lower initial serum concentrations (10-17 ng/mL), were strongly influenced by exposure during the ski season with indirect exposure contributing to 45% of PFOA serum concentrations. On the basis of these model simulations, an average metabolism yield of 0.003 (molar concentration basis; uncertainty range of 0.0006-0.01) was derived for transformation of 8:2 FTOH to PFOA. An uncertainty analysis was performed, and it was determined that the input parameters quantifying the intake of PFOA were mainly responsible for the uncertainty of the metabolism yield and the initial concentration of PFOA in serum was mainly contributing to the uncertainty of estimated serum half-lives.

  • 4.
    Gomis Ferreira, Melissa Ines
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Vestergren, Robin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. IVL Swedish Environmental Research Institute, Sweden.
    Borg, Daniel
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Comparing the toxic potency in vivo of long-chain perfluoroalkyl acids and fluorinated alternatives2018In: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 113, p. 1-9Article in journal (Refereed)
    Abstract [en]

    Since 2000, long-chain perfluoroalkyl acids (PFAAs) and their respective precursors have been replaced by numerous fluorinated alternatives. The main rationale for this industrial transition was that these alternatives were considered less bioaccumulative and toxic than their predecessors. In this study, we evaluated to what extent differences in toxicological effect thresholds for PFAAs and fluorinated alternatives, expressed as administered dose, were confounded by differences in their distribution and elimination kinetics. A dynamic one-compartment toxicokinetic (TK) model for male rats was constructed and evaluated using test data from toxicity studies for perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), perfluorobutane sulfonic acid (PFBS), perfluorooctanoic acid (PFOA), perfluoroctanesulfonic acid (PFOS) and ammonium 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)-propanoate (GenX). Dose-response curves of liver enlargement from sub-chronic oral toxicity studies in male rats were converted to internal dose in serum and in liver to examine the toxicity ranking of PFAAs and fluorinated alternatives. Converting administered doses into equivalent serum and liver concentrations reduced the variability in the dose-response curves for PFBA, PFHxA, PFOA and GenX. The toxicity ranking using modeled serum (GenX>PFOA>PFHxA>PFBA) and liver (GenX>PFOA≈PFHxA≈PFBA) concentrations indicated that some fluorinated alternatives have similar or higher toxic potency than their predecessors when correcting for differences in toxicokinetics. For PFOS and perfluorobutane sulfonic acid (PFBS) the conversion from administered dose to serum concentration equivalents did not change the toxicity ranking. In conclusion, hazard assessment based on internal exposure allows evaluation of toxic potency and bioaccumulation potential independent of kinetics and should be considered when comparing fluorinated alternatives with their predecessors.

  • 5.
    Gomis, Melissa I.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Vestergren, Robin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. IVL Swedish Environmental Research Institute, Sweden.
    MacLeod, Matthew
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Mueller, Jochen F.
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Historical human exposure to perfluoroalkyl acids in the United States and Australia reconstructed from biomonitoring data using population-based pharmacokinetic modelling2017In: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 108, p. 92-102Article in journal (Refereed)
    Abstract [en]

    Perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS) and perfluorohexanesulfonic acid (PFHxS) are found in the blood of humans and wildlife worldwide. Since the beginning of the 21st century, a downward trend in the human body burden, especially for PFOS and PFOA, has been observed while there is no clear temporal trend in wildlife. The inconsistency between the concentration decline in human serum and in wildlife could be indicative of a historical exposure pathway for humans linked to consumer products that has been reduced or eliminated. In this study, we reconstruct the past human exposure trends in two different regions, USA and Australia, by inferring the historical intake from cross-sectional biomonitoring data of PFOS, PFOA and PFHxS using a population-based pharmacokinetic model. For PFOS in the USA, the reconstructed daily intake peaked at 4.5 ng/kg-bw/day between 1988 and 1999 while in Australia it peaked at 4.0 ng/kg-bw/day between 1984 and 1996. For PFOA in the USA and Australia, the peak reconstructed daily intake was 1.1 ng/kg-bw/day in 1995 and 3.6 ng/kg-bw/day in 1992, respectively, and started to decline in 2000 and 1995, respectively. The model could not be satisfactorily fitted to the biomonitoring data for PFHxS within reasonable boundaries for its intrinsic elimination half-life, and thus reconstructing intakes of PFHxS was not possible. Our results indicate that humans experienced similar exposure levels and trends to PFOS and PFOA in the USA and Australia. Our findings support the hypothesis that near-field consumer product exposure pathways were likely dominant prior to the phase-out in industrialized countries. The intrinsic elimination half-life, which represents elimination processes that are common for all humans, and elimination processes unique to women (i.e., menstruation, cord-blood transfer and breastfeeding) were also investigated. The intrinsic elimination half-lives for PFOS and PFOA derived from model fitting for men were 3.8 and 2.4 years, respectively, for the USA, and 4.9 and 2 years respectively for Australia. Our results show that menstruation is a depuration pathway for PFOA for women, similarly but to a lesser extent compared to previous reports for PFOS. However menstruation, cord-blood transfer and breastfeeding together do not fully explain the apparently more rapid elimination of PFOA and PFOS by women compared to men; the intrinsic elimination half-lives in women were up to 13% lower for PFOS and up to 12% lower for PFOA compared to the corresponding half-lives in men.

  • 6. Hansen, Solrunn
    et al.
    Vestergren, Robin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. NILU Norwegian Institute for Air Research, Norway.
    Herzke, Dorte
    Melhus, Marita
    Evenset, Anita
    Hanssen, Linda
    Brustad, Magritt
    Sandanger, Torkjel M.
    Exposure to per- and polyfluoroalkyl substances through the consumption of fish from lakes affected by aqueous film-forming foam emissions - A combined epidemiological and exposure modeling approach. The SAMINOR 2 Clinical Study2016In: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 94, p. 272-282Article in journal (Refereed)
    Abstract [en]

    Releases of aqueous film-forming foams (AFFFs) from airport firefighting activities have been identified as important local point sources of per- and polyfluoroalkyl substances (PFASs) in nearby waterways. PFASs can be taken up by fish, and in turn by the humans that consume them. Despite the global extent of AFFF emissions, few studies exist on related impacts on humans. We aimed to investigate the associations between the consumption of fish from AFFF-affected waters and serum PFAS concentrations in humans using a combination of statistical tools, empirical data, and toxicokinetic modeling. Participants of the SAMINOR 2 Clinical Study were the basis far this study sample, which comprised 74 persons. Fifty-nine participants who reported consuming fish from AFFF-affected waters and 15 nonconsumers completed a questionnaire and gave serum samples. Participants were classified based on their consumption of trout and char: high (n = 16), moderate (n = 16), low (n = 27), and nonconsumers (n = 15); and serum samples were tested for the presence of 15 PFASs. Perfluorooctane sulfonic add (PFOS) was found in all participants, with the highest concentrations detected in the high consumption group (geometric means, 28 ng/mL) compared to the low consumption group and nonconsumers (10 and 11 ng/mL, respectively). In an analysis of variance contrast model, a significant, positive increasing trend was seen for fish consumption and PFOS, perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA). Toxicokinetic modeling allowed us to predict the median increases in serum concentrations of PFOS, PFHxS, and PFNA among high consumers within a factor of 2.2. The combination of statistical evaluation and toxicokinetic modeling clearly demonstrated a positive relationship between consumption of fish from AFFF-affected waters and serum PFAS concentrations. Further studies on dietary exposure to other PFASs present in AFFF and its consequences on human health are warranted.

  • 7. Haugdahl Nost, Therese
    et al.
    Vestergren, Robin
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM). NILU Norwegian Institute for Air Research, Norway.
    Berg, Vivian
    Nieboer, Evert
    Odland, Jon Øyvind
    Sandanger, Torkjel Manning
    Repeated measurements of per- and polyfluoroalkyl substances (PFASs) from 1979 to 2007 in males from Northern Norway: Assessing time trends, compound correlations and relations to age/birth cohort2014In: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 67, p. 43-53Article in journal (Refereed)
    Abstract [en]

    Background: Longitudinal biomonitoring studies can provide unique information on how human concentrations change over time, but have so far not been conducted for per- and polyfluoroalkyl substances (PFASs) in a background exposed population. Objectives: The objectives of this study were to determine: i) serum PFAS time trends on an individual level; ii) relative compositions and correlations between different PFASs; and iii) assess selected PFAS concentrations with respect to periodic (calendar year), age and birth cohort (APC) effects. Methods: Serum was sampled from the same 53 men in 1979, 1986, 1994, 2001 and 2007 in Northern Norway and analysed for 10 PFASs. APC effects were assessed by graphical and mixed effect analyses. Results: The median concentrations of perfluorooctane sulphonic acid (PFOS) and perfluorooctanoic acid (PFOA) increased five-fold from 1979 to 2001 and decreased by 26% and 23%, respectively, from 2001 to 2007. The concentrations of PFOS and PFOA peaked during 1994-2001 and 2001, respectively, whereas perfluorohexane sulphonic acid (PFHxS) increased to 2001, but did not demonstrate a decrease between 2001 and 2007. Perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA) displayed increasing trends throughout the entire study period (1979-2007). Although PFOS comprised dominating and stable proportions of PFAS burdens during these years, the contributions from PFOA and PFHxS were considerable. The evaluation of APC effects demonstrated that calendar year was the dominating influence on concentrations of PFOA, PFUnDA, and PFOS, although time-variant and weaker associations with age/birth cohort were indicated. Conclusions: The concentration changes of 10 PFASs in the repeated measurements from 1979 to 2007 demonstrated divergent time trends between the different PFASs. The temporal trends of PFASs in human serum during these 30 years reflect the overall trends in historic production and use, although global transport mechanisms and bioaccumulation potential of the different PFASs together with a varying extent of consumer exposure influenced the observed trends. Sampling year was the strongest descriptor of PFOA, PFUnDA and PFOS concentrations, and the calendar-year trends were apparent for all birth year quartiles. Discrepancies between the trends in this current longitudinal study and previous cross-sectional studies were observed and presumably reflect the different study designs and population characteristics.

  • 8.
    Johansson, Jana H.
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Berger, Urs
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Vestergren, Robin
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM). Norwegian Institute for Air Resarch NILU, Norway.
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Bignert, Anders
    Glynn, Anders
    Darnerud, Per Ola
    Temporal trends (1999-2010) of perfluoroalkyl acids in commonly consumed food items2014In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 188, p. 102-108Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to determine how dietary exposure to PFAAs has changed over the period when major production changes occurred. Archived samples (1999-2010) of eggs, milk and farmed rainbow trout were analyzed by ultra performance liquid chromatography coupled to tandem mass spectrometry. Statistically significant decreasing trends were observed for concentrations of perfluorooctane sulfonic acid (PFOS) and perfluorohexane sulfonic acid (PFHxS) in fish (p < 0.002 and p < 0.032, respectively) and eggs (p < 0.001 for both compounds). Concentrations of PFOS in fish and eggs decreased by a factor of 10 and 40, respectively. In eggs there was also a statistically significant decreasing trend in concentrations of perfluorooctanoic acid (PFOA). The results of this study demonstrate that PFAA concentrations in food items from agricultural food chains and aquatic food chains close to sources respond rapidly to changes in environmental emissions. Implications for the overall understanding of human exposure are discussed.

  • 9. Shi, Yali
    et al.
    Vestergren, Robin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. IVL Swedish Environmental Research Institute, Sweden.
    Haugdahl Nost, Therese
    Zhou, Zhen
    Cai, Yaqi
    Probing the Differential Tissue Distribution and Bioaccumulation Behavior of Per- and Polyfluoroalkyl Substances of Varying Chain-Lengths, Isomeric Structures and Functional Groups in Crucian Carp2018In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 52, no 8, p. 4592-4600Article in journal (Refereed)
    Abstract [en]

    Understanding the bioaccumulation mechanisms of per- and polyfluoroalkyl substances (PFASs) across different chain-lengths, isomers and functional groups represents a monumental scientific challenge with implications for chemical regulation. Here, we investigate how the differential tissue distribution and bioaccumulation behavior of 25 PFASs in crucian carp from two field sites impacted by point sources can provide information about the processes governing uptake, distribution and elimination of PFASs. Median tissue/blood ratios (TBRs) were consistently <1 for all PFASs and tissues except bile which displayed a distinct distribution pattern and enrichment of several perfluoroalkyl sulfonic acids. Transformation of concentration data into relative body burdens (RBBs) demonstrated that blood, gonads, and muscle together accounted for >90% of the amount of PFASs in the organism. Principal component analyses of TBRs and RBBs showed that the functional group was a relatively more important predictor of internal distribution than chain length for PFASs. Whole body bioaccumulation factors (BAFs) for short-chain PFASs deviated from the positive relationship with hydrophobicity observed for longer-chain homologues. Overall, our results suggest that TBR, RBB, and BAF patterns were most consistent with protein binding mechanisms although partitioning to phospholipids may contribute to the accumulation of long-chain PFASs in specific tissues.

  • 10. Shi, Yali
    et al.
    Vestergren, Robin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Xu, Lin
    Zhou, Zhen
    Li, Chuangxiu
    Liang, Yong
    Cai, Yaqi
    Human Exposure and Elimination Kinetics of Chlorinated Polyfluoroalkyl Ether Sulfonic Acids (Cl-PFESAs)2016In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 50, no 5, p. 2396-2404Article in journal (Refereed)
    Abstract [en]

    The incomplete mass-balance of organic fluorine in human serum indicates the existence of unknown per- and polyfluoroalkyl substances (PFASs) with persistent and bioaccumulative properties. Here we characterized human exposure and elimination kinetics of chlorinated polyfluoroalkyl ether sulfonic acids (Cl-PFESAs) in metal plating workers (n = 19), high fish consumers (n = 45), and background controls (n = 8). Cl-PFESAs were detected in >98% of the sampled individuals with serum concentrations ranging <0.019-5040 ng/mL. Statistically higher median serum levels were observed in high fish consumers (93.7 ng/mL) and metal plating workers (51.5 ng/mL) compared to the background control group (4.78 ng/mL) (Kruskal Wallis rank sum test, p < 0.01). Cl-PFESAs could account for 0.269 to 93.3% of Sigma PFASs in human serum indicating that this compound class may explain a substantial fraction of previously unidentified organic fluorine in the Chinese population. Estimated half-lives for renal clearance (median 280 years; range 7.1-4230 years) and total elimination (median 15.3 years; range 10.1-56.4 years) for the eight carbon Cl-PFESA suggest that this is the most biopersistent PFAS in humans reported to date. The apparent ubiquitous distribution and slow elimination kinetics in humans underscore the need for more research and regulatory actions on Cl-PFESAs and PFAS alternatives with similar chemical structures.

  • 11. Shi, Yali
    et al.
    Vestergren, Robin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Zhou, Zhen
    Song, Xiaowei
    Xu, Lin
    Liang, Yong
    Cai, Yaqi
    Tissue Distribution and Whole Body Burden of the Chlorinated Polyfluoroalkyl Ether Sulfonic Acid F-53B in Crucian Carp (Carassius carassius): Evidence for a Highly Bioaccumulative Contaminant of Emerging Concern2015In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, no 24, p. 14156-14165Article in journal (Refereed)
    Abstract [en]

    Following the global actions to phase out perfluoroctanesulfonic acid (PFOS) a large number of alternative per- and polyfluoroalkyl substances, with poorly defined hazard properties, are being used in increasing quantities. Here, we report on the first detection of the chlorinated polyfluoroalkyl ether sulfonic acid F-53B in biological samples and determine the tissue distribution and whole body bioaccumulation factors (BAF(whole body)) in crucian carp (Carassius carassius). Analysis of fish samples from Xiaoqing River (XR) and Tangxun Lake (TL) demonstrated a similar level of F-53B contamination with median concentrations in blood of 41.9 and 20.9 ng/g, respectively. Tissue/blood ratios showed that distribution of F-53B primarily occurs to the kidney (TL: 0.48, XR: 0.54), gonad (TL: 0.36, XR: 0.54), liver (TL: 0.38, XR: 0.53), and heart (TL: 0.47, XR: 0.47). Median Log BAF(whole body) values for F-53B (XR: 4.124, TL: 4.322) exceeded regulatory bio accumulation criterion and were significantly higher than those of PFOS in the same data sets (XR: 3.430, TL: 3.279). On the basis of its apparent omnipresence and strong bioaccumulation propensity, it is hypothesized that F-53B could explain a significant fraction of previously unidentified organofluorine in biological samples from China, and regulatory actions for this compound are encouraged.

  • 12.
    Ullah, Shahid
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Alsberg, Tomas
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Vestergren, Robin
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Berger, Urs
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Determination of perfluoroalkyl carboxylic, sulfonic, and phosphonic acids in food2012In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 404, no 8, p. 2193-2201Article in journal (Refereed)
    Abstract [en]

    A sensitive and accurate method was developed and validated for simultaneous analysis of perfluoroalkyl carboxylic acids, sulfonic acids, and phosphonic acids (PFPAs) at low picograms per gram concentrations in a variety of food matrices. The method employed extraction with acetonitrile/water and cleanup on a mixed-mode co-polymeric sorbent (C8 + quaternary amine) using solid-phase extraction. High-performance liquid chromatographic separation was achieved on a C18 column using a mobile phase gradient containing 5 mM 1-methyl piperidine for optimal chromatographic resolution of PFPAs. A quadrupole time-of-flight high-resolution mass spectrometer operating in negative ion mode was used as detector. Method detection limits were in the range of 0.002 to 0.02 ng g(-1) for all analytes. Sample preparation (extraction and cleanup) recoveries at a spiking level of 0.1 ng g(-1) to a baby food composite were in the range of 59 to 98 %. A strong matrix effect was observed in the analysis of PFPAs in food extracts, which was tentatively assigned to sorption of PFPAs to the injection vial in the solvent-based calibration standard. The method was successfully applied to a range of different food matrices including duplicate diet samples, vegetables, meat, and fish samples.

  • 13.
    Vestergren, R
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Cousins, I
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Human Exposure to Perfluorinated Compounds2008In: Naturvårdsverket: 27 May, 2008Conference paper (Refereed)
  • 14.
    Vestergren, R
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Cousins, I
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Trudel, D.
    Wormuth, M.
    Scheringer, M.
    Considering the role of precursor compounds in consumer exposure to PFOS and PFOA2008In: Fluorinated Surfactants New Developments: 1st International Workshop: 26-28 June, Idstein, Germany, 2008Conference paper (Refereed)
  • 15.
    Vestergren, R
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Cousins, I
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Trudel, D.
    Wormuth, M.
    Scheringer, M.
    Considering the role of precursor compounds in consumer exposure to PFOS and PFOA2008In: Dioxin 2008: 17-22 August, Birmingham, UK, 2008Conference paper (Refereed)
  • 16.
    Vestergren, R
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Cousins, I
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Trudel, D.
    Wormuth, M.
    Scheringer, M.
    Considering the role of precursor compounds in consumer exposure to PFOS and PFOA2008In: Organohalogen Compd., Vol. 70, p. 1442-1466Article in journal (Refereed)
  • 17.
    Vestergren, R
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Cousins, I
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Trudel, D.
    Wormuth, M.
    Scheringer, M.
    Estimating the contribution of precursor compounds in consumer exposure to PFOS and PFOA2008In: Chemosphere, Vol. 73, p. 1617-1624Article in journal (Refereed)
  • 18.
    Vestergren, Robin
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Human exposure to perfluoroalkyl acids2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulfonic acids (PFSAs) are persistent organic contaminants which have been globally measured in human serum samples at low μg L-1 concentrations. One hypothesis, the so-called "indirect hypothesis", postulates that exposure to precursor compounds is responsible for the presence of PFCAs and PFSAs in human serum. The main purpose of this thesis was to test an alternative hypothesis that direct intake of PFCAs and PFSAs via the diet is the dominant ongoing pathway of exposure. Exposure modeling results in paper I and II demonstrate that dietary intake is the major exposure pathway of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), while known precursors account for only a few percent of the total exposure. To address the uncertainties related to dietary intake pathways, highly sensitive analytical methods for a range of PFCAs and PFSAs are developed, validated and applied in paper III and IV. By the development of a novel analytical technique in paper III, detection limits in the pg g-1 range are achieved for a wide range of analytes in different food categories. Analysis of a large set of food basket samples from the Swedish market in paper IV shows that the concentrations in many dietary samples are lower than those used to estimate exposure to PFOA and PFOS in paper I and II. However, an updated dietary intake estimate in paper IV supports the conclusion of paper I and II that dietary intake is the major ongoing human exposure pathway for the general population. Pharmacokinetic modeling undertaken in paper II was reevaluated in this thesis and back-calculated daily intakes from serum concentrations of PFOA and PFOS are shown to be in agreement with the estimated dietary intakes from paper IV. However, due to uncertainties and simplifying assumptions in the pharmacokinetic model, it is possible that there are additional pathways of human exposure contributing to human serum levels.

  • 19.
    Vestergren, Robin
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Berger, Urs
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Glynn, Anders
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Dietary exposure to perfluoroalkyl acids for the Swedish population in 1999, 2005 and 20102012In: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 49, p. 120-127Article in journal (Refereed)
    Abstract [en]

    Dietary intake has been hypothesized to be the major pathway of human exposure to perfluoroalkyl acids (PFAAs). However, difficulties associated with the analysis of PFAAs at ultra trace levels in food samples have prevented the confirmation of this hypothesis. In this study, the dietary intake of PFAAs for the general Swedish population was estimated by applying a highly sensitive analytical method to a set of archived food market basket samples from 1999, 2005 and 2010. Dietary exposure to perfluorooctane sulfonic acid (PFOS) (860-1440 pg kg(-1) day(-1)), perfluoroundecanoic acid (PFUnDA) (90-210 pg kg(-1) day(-1)), perfluorodecanoic acid (PFDA) (50-110 pg kg(-1) day(-1)) and perfluorononanoic acid (PFNA) (70-80 pg kg(-1) day(-1)) was dominated by the consumption of fish and meat. In contrast, dietary exposure to PFOA (350-690 pg kg(-1) day(-1)) originated from low levels (8-62 pg g(-1)) found in several high consumption food categories including cereals, dairy products, vegetables and fruit. The dietary intakes of PFOS and PFOA estimated in this study were 4 to 10 times lower compared to previous exposure modeling studies. Nevertheless, the dietary intake of PFOS and PFOA was still a factor of 6 to 10 higher than exposure through ingestion of household dust and drinking water estimated for the general Swedish population. For perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA) and perfluorohexane sulfonic acid (PFHxS) drinking water intake was the major exposure pathway (36-53% of the total exposure) whereas dust ingestion made a significant contribution (27-49%) to the total exposure for PFHxA, PFHpA, PFNA, perfluorotridecanoic acid (PFTrDA) and perfluorotetradecanoic acid (PFTeDA). Dietary intakes varied by less than a factor of three for all PFAAs during the different sampling years which demonstrates that dietary intake has been fairly constant over the past decade when many manufacturing changes occurred.

  • 20.
    Vestergren, Robin
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Berger, Urs
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Glynn, Anders
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Dietary intake estimates of perfluoroalkyl carboxylic acids and perfluoroalkane sulfonic acids for the general Swedish population in 1999, 2005 and 2010Manuscript (preprint) (Other academic)
    Abstract [en]

    Dietary intake has been estimated to be the major ongoing pathway of human exposure to perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulfonic acids (PFSAs). However, difficulties associated with the analysis of food samples have hampered the reliable quantification of dietary exposure. Here the dietary exposure of the average Swedish population to PFCAs and PFSAs is estimated through analysis of a range of homologues in representative food basket samples from 1999, 2005 and 2010. Exposure to perfluorooctane sulfonate (796−1424 pg kg

    -1day-1), perfluoroundecanoic acid (88−212 pg kg-1day-1), perfluorodecanoic acid (52−102 pg kg-1day-1) and perfluorononanoic acid (62−83 pg kg-1day-1) was dominated by the consumption of fish and meat. In contrast, exposure to perfluorooctanoic acid (322−513 pg kg-1day-1) originated from low levels (8−62 pg g-1) found in several ―high consumption‖ food categories including cereals, dairy products, vegetables and fruit. The average body weight normalized dietary intakes (pg kg-1day-1) were fairly constant between 1999 and 2010 for all PFCAs and PFSAs demonstrating that dietary intake has been a continuous exposure pathway for these compounds during this period when many manufacturing changes occurred. Although statistically significant temporal trends in the average dietary intake estimates could not be determined, there is preliminary evidence of a downward time trend in the concentrations of PFOS in eggs and meat products and an upward trend of PFDA, PFUnDA, perfluorododecanoic acid and perfluorotridecanoic acid in fish products, which both warrant further investigation. In line with recent studies, dietary intake was found to be the major ongoing human exposure pathway for both PFOA and PFOS (~70% of the total exposure) for the Swedish population compared to exposure via ingestion of household dust and drinking water. The calculated higher total dietary exposure to PFOA compared to PFNA is consistent with the pattern observed in human serum, although there are several other exposure pathways which could explain this homologue pattern in serum.

  • 21.
    Vestergren, Robin
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Human dietary exposure to per- and poly-fluoroalkyl substances (PFASs)2013In: Persistent organic pollutants and toxic metals in foods / [ed] Rose, M.; Fernandes, A., Cambridge: Woodhead Publishing Limited, 2013, no 247, p. 279-307Chapter in book (Refereed)
    Abstract [en]

    Per- and polyfluoroalkyl substances (PFASs) are a class of emerging contaminants with numerous industrial and commercial applications. Within this class the best studied substances are the perfluoroalkane sulfonates (PFSAs) and perfluoroalkyl carboxylates (PFCAs). PFSAs and PFCAs have been detected in human serum samples from all around the world and are ubiquitous in the global environment and wildlife. As well as being completely resistant to environmental degradation, some PFSAs and PFCAs are bioaccumulative and potentially toxic, which raises a concern about population-wide exposure to this group of substances. Dietary intake has been suggested as a major pathway of human exposure to the two most widely studied substances among PFSAs and PFCAs, namely perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). However, the difficulties associated with the analysis of PFSAs, PFCAs and related PFASs at ultra-trace levels in food samples have hampered the understanding of human exposure. Recent advances in analytical chemistry have dramatically improved the ability to measure these substances and other PFASs in food matrices, and method detection limits down to low picogram per gram food can now be reached. Worldwide interlaboratory studies also indicate that the accuracy and precision of analytical methods have significantly improved over the last decade. These modern methods have been applied to quantify human dietary exposure to PFCAs and PFSAs in several European countries. Overall, the exposure to PFOS and PFOA from diet is typically a factor of 6 to 10 higher than the exposure from other known exposure pathways for the general adult population of Western countries. Furthermore, application of toxicokinetic models indicates that present day serum concentrations of PFOS and PFOA can largely be explained by the estimated dietary exposures. Despite the recent advances in analytical techniques, the sources of food contamination are not very well characterized. It has been demonstrated that bioaccumulation and biomagnification in aquatic food webs is a primary transfer mechanism for PFOS and several long-chain perfluoroalkyl carboxylic acids to the human diet. However, more research is needed to understand the accumulation of PFASs in terrestrial food webs and the transfer of a range of PFASs from food-contact materials.

  • 22.
    Vestergren, Robin
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Cousins, Ian T
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Tracking the pathways of human exposure to perfluorocarboxylates2009In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 43, no 15, p. 5565-75Article in journal (Refereed)
    Abstract [en]

    Recent analyses of perfluorooctanoate (PFOA) in human blood sera show that the background-exposed population in industrialized countries worldwide exhibits a narrow concentration range; arithmetic means of published studies range between 2 and 8 microg/L PFOA, with the exception of a few outlier studies. The globally comparable human serum concentrations of PFOA and characteristic dominance of PFOA with respect to other perfluorocarboxylate (PFCA) homologues indicate that exposure pathways of humans differ from those of wildlife, where perfluorononanoate (PFNA) is often the dominant homologue. The observed correlations between perfluorooctane sulfonate (PFOS) and PFOA in human serum together with a simultaneous downward time trend of these compounds in human blood sera and blood spots from the year 2000 onward indicate a connection between historical perfluorooctanesulfonyl (POSF) production (phased out by the major manufacturer in 2000-2002) and exposure to both PFOS and PFOA. A comparison of estimated daily intakes to humans based on samples from exposure media (collected post 2000) indicates that food intake is the major contemporary exposure pathway for the background population, whereas drinking water exposure is dominant for populations near sources of contaminated drinking water. A one-compartment pharmacokinetic model used to back-calculate daily intakes from serum levels is shown to provide agreement within a factor of 1.5-5.5 of the daily intakes derived from exposure media, which provides further supporting evidence that dietary exposure is a major ongoing exposure pathway of PFOA to the background population.

  • 23.
    Vestergren, Robin
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Trudel, David
    Wormuth, Mattias
    Scheringer, Martin
    Estimating the contribution of precursor compounds in consumer exposure to PFOS and PFOA2008In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 73, no 10, p. 1617-1624Article in journal (Refereed)
    Abstract [en]

    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.

  • 24.
    Vestergren, Robin
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Orata, Francis
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Berger, Urs
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Bioaccumulation of perfluoroalkyl acids in dairy cows in a naturally contaminated environment2013In: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 20, no 11, p. 7959-7969Article in journal (Refereed)
    Abstract [en]

    Beef and dairy products may be important vectors of human exposure to perfluoroalkyl acids (PFAAs), but the understanding of how PFAAs are accumulated and transferred through agricultural food chains is very limited. Here, the bioaccumulation of PFAAs in dairy cows receiving naturally contaminated feed and drinking water was investigated by conducting a mass balance of PFAAs for a herd of dairy cows in a barn on a typical Swedish dairy farm. It was assumed that the cows were able to reach steady state with their dietary intake of PFAAs. Perfluorooctane sulfonic acid (PFOS) and perfluoroalkyl carboxylic acids (PFCAs) with 8 to 12 carbons were detected in cow tissue samples (liver, muscle, and blood) at concentrations up to 130 ng kg(-1). Mass balance calculations demonstrated an agreement between total intake and excretion within a factor of 1.5 and consumption of silage was identified as the dominant intake pathway for all PFAAs. Biomagnification factors (BMFs) were highly tissue and homologue specific. While BMFs of PFOS and PFCAs with 9 and 10 fluorinated carbons in liver ranged from 10 to 20, perfluorooctanoic acid (PFOA) was not biomagnified (BMF < 1) in any of the investigated tissues. Biotransfer factors (BTFs; defined as the concentration in tissue divided by the total daily intake) were calculated for muscle and milk. Log BTFs ranged from -1.95 to -1.15 day kg(-1) with the highest BTF observed for PFOS in muscle. Overall, the results of this study suggest that long-chain PFAAs have a relatively high potential for transfer to milk and beef from the diet of dairy cows. However, a low input of PFAAs to terrestrial systems via atmospheric deposition and low bioavailability of PFAAs in soil limits the amount of PFAAs that enter terrestrial agricultural food chains in background contaminated environments and makes this pathway less important than aquatic exposure pathways. The BTFs estimated here provide a useful tool for predicting human exposure to PFAAs via milk and beef under different contamination scenarios.

  • 25.
    Vestergren, Robin
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Ullah, Shahid
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Berger, Urs
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    A matrix effect-free method for reliable quantification of perfluoroalkyl carboxylic acids and perfluoroalkane sulfonic acids at low parts per trillion levels in dietary samplesManuscript (preprint) (Other academic)
    Abstract [en]

    In recent exposure modeling studies diet has been identified as the dominant pathway of human exposure to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). However, the paucity of highly sensitive and accurate analytical data to support these studies means that their conclusions are open to question. Here a novel matrix effect-free method is described for ultra-trace analysis of perfluoroalkyl carboxylic acids (PFCAs, all homologues from perfluorohexanoic acid to perfluorododecanoic acid) and perfluoroalkane sulfonic acids (PFSAs, perfluorohexane and perfluorooctane sulfonic acid) in dietary samples of varied composition. The method employs ion pair extraction of the analytes into methyl

    tert-butyl ether and subsequent solid phase extraction clean-up on Florisil and graphitized carbon. Instrumental analysis was undertaken using ultra performance liquid chromatography coupled to tandem mass spectrometry. Special care was taken to avoid procedural blank contamination and potential contamination sources were elucidated. The performance of the method was evaluated for five different food test matrices including a duplicate diet sample. Method detection limits in the low to sub pg g-1 range were obtained for all target analytes, which are 5-100 times more sensitive than previously reported for duplicate diet samples. The method provided recoveries consistently between 50 and 80% for all analytes in the food matrices tested and effects of co-extracted matrix constituents on ionization were found to be negligible. Acceptable precision, defined as percentage relative standard deviation <30%, was achieved for all analytes. Accurate quantification at ultra-trace levels was demonstrated by a method intercomparison study with an independent recently developed method. For the first time the presence of long-chain PFCAs in duplicate diet samples is reported. The method presented here can thus support an improved assessment of dietary exposure to PFCAs and PFSAs. Re-analysis of duplicate diet samples, which had been previously analyzed using another older analytical methodology, indicated that human exposure to PFOA and PFOS from dietary sources may previously have been overestimated

  • 26.
    Vestergren, Robin
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Ullah, Shahid
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Berger, Urs
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    A matrix effect-free method for reliable quantification of perfluoroalkyl carboxylic acids and perfluoroalkane sulfonic acids at low parts per trillion levels in dietary samples2012In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1237, p. 64-71Article in journal (Refereed)
    Abstract [en]

    In recent exposure modeling studies diet has been identified as the dominant pathway of human exposure to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). However, the paucity of highly sensitive and accurate analytical data to support these studies means that their conclusions are open to question. Here a novel matrix effect-free method is described for ultra-trace analysis of perfluoroalkyl carboxylic acids and perfluoroalkane sulfonic acids in dietary samples of varied composition. The method employs ion pair extraction of the analytes into methyl tert-butyl ether and subsequent solid phase extraction clean-up on Florisil and graphitized carbon. The target compounds are separated and detected using ultra performance liquid chromatography coupled to tandem mass spectrometry. Special care was taken to avoid procedural blank contamination and potential contamination sources were elucidated. The performance of the method was validated for five different food test matrices including a duplicate diet sample. Method detection limits in the low to sub pg g(-1) range were obtained for all target analytes, which is 5-100 times more sensitive than previously reported for duplicate diet samples. Total method recoveries were consistently between 50 and 80% for all analytes in all tested food matrices and effects of co-extracted matrix constituents on ionization of the target compounds were found to be negligible. The precision of the method (defined as percentage relative standard deviation) at concentrations close to the respective method limits of quantification was <15% for all analytes. Accurate quantification at ultra-trace levels was demonstrated by laboratory control spike experiments. For the first time the presence of long-chain PFCAs in duplicate diet samples is reported. The method presented here can thus support an improved assessment of human exposure from dietary intake for a range of PFCA and PFSA homologues. Re-analysis of duplicate diet samples, which had been analyzed earlier using another analytical methodology, indicated that dietary intake of PFOA and PFOS may previously have been overestimated.

  • 27. Wang, Thanh
    et al.
    Vestergren, Robin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Norwegian Institute for Air Research (NILU), FRAM − High North Research Centre on Climate and the Environment, Norway.
    Herzke, Dorte
    Yu, Junchao
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Levels, Isomer Profiles, and Estimated Riverine Mass Discharges of Perfluoroalkyl Acids and Fluorinated Alternatives at the Mouths of Chinese Rivers2016In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 50, no 21, p. 11584-11592Article in journal (Refereed)
    Abstract [en]

    An extensive sampling campaign was undertaken to study the levels, isomer profiles and riverine mass discharges of perfluoroalkyl acids (PFAAs) and fluorinated alternatives in 19 Chinese rivers. The levels and homologue profiles of Sigma(10)PFAAs varied considerably among the 19 rivers (mean 106; median 16.3, range 8.91240 ng/L), indicating the influence of specific point sources. Highly branched isomer profiles of perfluorooctanoic acid (1825% br-PFOA) in rivers with elevated concentrations (96352 ng/L) indicate that releases during production of PFOA by electrochemical fluorination and/or its use in fluoropolymer manufacture were the dominant sources to these rivers. The fluorinated alternatives 6:2 fluorotelomer sulfonate (detection frequency 21%, < 0.13.1 ng/L) and chlorinated polyfluoroalkyl ether sulfonate F-53B (51%, < 0.5678.5 ng/L) were also found in some rivers. The total Chinese riverine mass discharges of PFOA (mean 80.9; range 16.8168 t/y) (including monitoring data from this and other studies) were in good agreement with theoretical PFOA emission estimates (17.3203 t/y) whereas riverine mass discharges of PFOS (mean 3.6; range 1.95.6 t/y) could only account for a minor fraction of theoretically estimated PFOS releases (70 t/y). This study provides empirical evidence that emissions from Chinese point sources likely dominate the global emissions of several legacy PFASs (notably PFOA) and fluorinated alternatives (e.g., F-53B).

  • 28. Wang, Yuan
    et al.
    Shi, Yali
    Vestergren, Robin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. IVL Swedish Environmental Research Institute, Sweden.
    Zhou, Zhen
    Liang, Yong
    Cai, Yaqi
    Using hair, nail and urine samples for human exposure assessment of legacy and emerging per- and polyfluoroalkyl substances2018In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 636, p. 383-391Article in journal (Refereed)
    Abstract [en]

    Non-invasive samples present ethical and practical benefits for investigating human exposure to hazardous contaminants, but analytical challenges and difficulties to interpret the results limit their application in biomonitoring. Here we investigated the potential for using hair, nail and urine samples as a measure of internal exposure to an array of legacy and emerging per- and polyfluoroalkyl substances (PFASs) in two populations with different exposure conditions. Paired urine-serum measurements of PFASs from a group of highly exposed fishery employees displayed strong correlations for PFASs with three to eight perfluorinated carbons (p > 0.653; p < 0.01). Consistent statistical correlations and transfer ratios in nails and hair from both populations demonstrated that these non-invasive samples can be used as a measure of internal exposure to perfluorooctane sulfonic acid and CS chlorinated polyfluoralkyl ether sulfonic acid (CS Cl-PFESA). Contrastingly, the infrequent detections and or lack of consistent transfer ratios for perfluorooctanoic acid, perfluorononanoic acid and short-chain PFASs in hair and nail samples indicate passive uptake from the external environment rather than uptake and internal distribution. Collectively, the study supports the use of urine samples as a valid measure of internal exposure for a range of short- and medium-chain PFASs, while the validity of nail and hair samples as a measure of internal exposure may vary for different PFASs and populations. The ubiquitous detection of C8 CI-PFESA in all sample matrices from both populations indicates widespread exposure to this contaminant of emerging concern in China.

  • 29. Wang, Yuan
    et al.
    Vestergren, Robin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Shi, Yali
    Cao, Dong
    Xu, Lin
    Cai, Yaqi
    Zhao, Xiaoli
    Wu, Fengchang
    Identification, Tissue Distribution, and Bioaccumulation Potential of Cyclic Perfluorinated Sulfonic Acids Isomers in an Airport Impacted Ecosystem2016In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 50, no 20, p. 10923-10932Article in journal (Refereed)
    Abstract [en]

    The use of cyclic perfluoroalkyl acids as anticorrosive agents in hydraulic fluids remains a poorly characterized source of organofluorine compounds to the environment. Here, we investigated the presence of perfluoroethylenecyclohexanesulfonate (PFECHS) isomers in environmental samples for the first time using a combination of high resolution and tandem mass spectrometry. Five distinct peaks attributed to different isomers of PFECHS and perfluoropropylcyclopentanesulfonate (PFPCPeS) were identified in environmental samples. The sum of PFECHS and PFPCPeS isomers displayed logarithmically decreasing spatial trends in water (1.04-324 ng/L) and sediment samples (<MLQ 2.23 ng/g dw) with increasing distance from Beijing international airport. PFECHS and PFPCPeS displayed the highest accumulation in liver, kidney, blood and bladder and average whole body bioaccumulation factors (log BAF(whole-body)) were estimated to be 2.7 and 1.9 respectively. Isomer-specific differences in the tissue/blood distribution ratios and BAF(whole-body) indicate that ring structure and position of the sulfonic acid group affect the bioaccumulation potential of cyclic perfluoroalkyl acids. Based on the high mobility and moderate bioaccumulation potential of cyclic perfluorinated acids it is suggested that contamination of aquifers used for drinking water around airports may be a hitherto overlooked problem for this novel class of contaminants.

  • 30.
    Winkens, Kerstin
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Koponen, Jani
    Schuster, Jasmin
    Shoeib, Mahiba
    Vestergren, Robin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Berger, Urs
    Karvonen, Anne M.
    Pekkanen, Juha
    Kiviranta, Hannu
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Perfluoroalkyl acids and their precursors in indoor air sampled in children's bedrooms2017In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 222, p. 423-432Article in journal (Refereed)
    Abstract [en]

    The contamination levels and patterns of perfluoroallcyl acids (PFAAs) and their precursors in indoor air of children's bedrooms in Finland, Northern Europe, were investigated. Our study is among the most comprehensive indoor air monitoring studies (n = 57) and to our knowledge the first one to analyse air in children's bedrooms for PFASs (17 PFAAs and 9 precursors, including two acrylates, 6:2 FTAC and 6:2 FTMAC). The most frequently detected compound was 8:2 fluorotelomer alcohol (8:2 FTOH) with the highest median concentration (3570 pg/m(3)). FTOH concentrations were generally similar to previous studies, indicating that in 2014/2015 the impact of the industrial transition had been minor on FTOH levels in indoor air. However, in contrast to earlier studies (with one exception), median concentrations of 6:2 FTOH were higher than 10:2 FTOH. The C8 PFAAs are still the most abundant acids, even though they have now been phased out by major manufacturers. The mean concentrations of FOSE/As, especially MeFOSE (89.9 pg/m(3)), were at least an order of magnitude lower compared to previous studies. Collectively the comparison of FTOHs, PFAAs and FOSE/FOSAs with previous studies indicates that indoor air levels of PFASs display a time lag to changes in production of several years. This is the first indoor air study investigating 6:2 FTMAC, which was frequently detected (58%) and displayed some of the highest maximum concentrations (13 000 pg/m(3)). There were several statistically significant correlations between particular house and room characteristics and PFAS concentrations, most interestingly higher EtFOSE air concentrations in rooms with plastic floors compared to wood or laminate.

  • 31.
    Winkens, Kerstin
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Vestergren, Robin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Swedish Environmental Research Institute IVL, Sweden.
    Berger, Urs
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Early life exposure to per- and polyfluoroalkyl substances (PFASs): A critical review2017In: Emerging Contaminants, ISSN 2405-6650, E-ISSN 2405-6642, Vol. 3, no 2, p. 55-68Article in journal (Refereed)
    Abstract [en]

    Due to the dynamic developmental processes during pregnancy, infancy, childhood and adolescence, exposure to PFASs is hypothesized to have the most pronounced negative effects during this period. In this review we critically evaluate the current state of the science regarding human early life exposure processes (until 18 years of age) to per- and polyfluoroalkyl substances (PFASs). Efficient placental transfer of perfluoroalkyl acids (PFAAs) results in relatively high prenatal exposure compared with many neutral organic contaminants. The few biomonitoring studies that specifically target infants, toddlers and other children suggest relatively high serum concentrations of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in early life with peak concentrations occurring sometime before the child reaches 20 months. This peak in serum concentrations is most likely explained by exposure via breastfeeding, ingestion of house dust and/or specific contact events with consumer products leading to high body weight normalized estimated daily intakes (EDIs). Although children have higher EDIs of PFASs than adults, these are not always reflected by higher serum levels of PFASs in children in cross-sectional biomonitoring studies due to the confounding effect of age and birth cohort, and different exposure histories due to production changes. Longitudinal exposure studies measuring internal and external exposure (for multiple pathways and PFASs) at several time points during early life are strongly encouraged to understand temporal changes in exposure of individual children. A better quantitative understanding of early life exposure processes would help to improve the validity of epidemiological studies and allow informed decisions regarding setting of regulatory thresholds and appropriate mitigation actions.

  • 32. Zhang, Haiyan
    et al.
    Vestergren, Robin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. FRAM − High North Research Centre on Climate and the Environment, Norway.
    Wang, Thanh
    Yu, Junchao
    Jiang, Guibin
    Herzke, Dorte
    Geographical Differences in Dietary Exposure to Perfluoroalkyl Acids between Manufacturing and Application Regions in China2017In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, no 10, p. 5747-5755Article in journal (Refereed)
    Abstract [en]

    Emissions of perfluoroalkyl acids (PFAAs) have increased in China over the past decade, but human exposure pathways are poorly understood. Here we analyzed 15 PFAAs in commonly consumed food items and calculated body weight normalized dietary intake rates (estimated dietary intake, EDIs) in an area with ongoing PFAA production (Hubei province; n = 121) and an urbanized coastal area (Zhejiang province; n = 106). Geographical differences in concentrations were primarily observed for perfluorooctanesulfonic acid (PFOS) and perfluorohexanesulfonic acid (PFHxS) in animal food items and short chain PFAAs in vegetable food items. The average EDI of Sigma PFAAs for adults in Hubei (998 ng kg(-1) day(-1)) was more than 2 orders of magnitude higher than that in Zhejiang (9.03 ng kg-1 day(-1)). In Hubei province, the average EDI of PFOS for adults (87 ng kg(-1) day(-1)) was close to or exceeded advisory guidelines used in other countries indicating health risks for the population from long-term exposure. Yet, PFOS could only account for about 10% of the EDI of Sigma PFAAs in the Hubei province, which was dominated by short-chain PFAAs through consumption of vegetables. The large contribution of short-chain PFAAs to the total EDIs in manufacturing areas emphasize the need for improved exposure and hazard assessment tools of these substances.

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