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Per- and polyfluoroalkyl substances (PFAS) have raised concerns due to their worldwide occurrence and adverse effects on both the environment and humans as well as posing challenges for monitoring. Further collection of information is required for a better understanding of their occurrence and the unknown fractions of the extractable organofluorine (EOF) not explained by commonly monitored target PFAS. In this study, eight pairs of raw and treated water were collected from drinking water treatment plants (DWTPs) around Taihu Lake in China and analyzed for EOF and 34 target PFAS. Mass balance analysis of organofluorine revealed that at least 68% of EOF could not be explained by target PFAS. Relatively higher total target concentrations were observed in 4 DWTPs (D1 to D4) when compared to other samples with the highest sum concentration up to 189 ng L−1. PFOA, PFOS and PFHxS were the abundant compounds. Suspect screening analysis identified 10 emerging PFAS (e.g., H-PFAAs, H-PFESAs and OBS) in addition to target PFAS in raw or treated water. The ratios PFBA/PFOA and PFBS/PFOS between previous and current studies showed significant replacements of short-chain to long-chain PFAS. The ratios of the measured PFAS concentrations to the guideline values showed that some of the treated drinking water exceeds guideline values, appealing for efforts on drinking water safety guarantee. [ABSTRACT FROM AUTHOR]

Livers of caribou and reindeer (Rangifer tarandus) from Canada (n = 146), Greenland (n = 30), Svalbard (n = 7), and Sweden (n = 60) were analyzed for concentrations of eight perfluoroalkyl carboxylic acids and four perfluoroalkane sulfonic acids. In Canadian caribou, PFNA (range < 0.01–7.4 ng/g wet weight, ww) and PFUnDA (<0.01–5.6 ng/g ww) dominated, whereas PFOS predominated in samples from South Greenland, Svalbard, and Sweden, although the highest concentrations were found in caribou from Southwest Greenland (up to 28 ng/g ww). We found the highest median concentrations of all PFAS except PFHxS in Akia-Maniitsoq caribou (Southwest Greenland, PFOS 7.2–19 ng/g ww, median 15 ng/g ww). The highest concentrations of ΣPFAS were also found in Akia-Maniitoq caribou (101 ng/g ww) followed by the nearby Kangerlussuaq caribou (45 ng/g ww), where the largest airport in Greenland is situated, along with a former military base. Decreasing trends in concentrations were seen for PFOS in the one Canadian and three Swedish populations. Furthermore, PFNA, PFDA, PFUnDA, PFDoDA, and PFTrDA showed decreasing trends in Canada's Porcupine caribou between 2005 and 2016. In Sweden, PFHxS increased in the reindeer from Norrbotten between 2003 and 2011. The reindeer from Västerbotten had higher concentrations of PFNA and lower concentrations of PFHxS in 2010 compared to 2002. Finally, we observed higher concentrations in 2010 compared to 2002 (albeit statistically insignificant) for PFHxS in Jämtland, while PFNA, PFDA, PFUnDA, PFDoDA, and PFTrDA showed no difference at all. [ABSTRACT FROM AUTHOR]

The sorption processes of persistent organic pollutants on microplastics particles are poorly understood. Therefore, the present study investigated the sorption processes of perfluorooctanesulfonate (PFOS) on polyethylene (PE) microplastic particles (MPs) which are representing a prominent environmental pollutant and one of the most abundant microplastic polymers in the aquatic environment, respectively. The focus was set on the investigation of the impact of the particle size on PFOS sorption using four different PE MPs size ranges. The sorption kinetics for 6 months was studied with one selected size range of PE MPs. Besides, the desorption of PFOS from PE MPs under simulated digestive conditions was carried out by using artificial gut fluid mimicking the intestinal juice of fish. The investigation of the size effects of particles over 6 months demonstrated a linear increase of PFOS concentration sorbed onto PE with a decrease of the particle size. Thus, our findings implicate efficient sorption of PFOS onto PE MPs of different sizes. The results showed that PFOS desorbed from the PE MPs into the artificial gut fluid with a rate of 70 to 80%. Besides, a longer exposure of PE MPs to PFOS leads to a higher concentration adsorbed by PE MPs, which may favor the ingestion of higher concentration of PFOS, and thus represents a higher risk to transfer relevant concentrations of PFOS during digestion. [ABSTRACT FROM AUTHOR]

The high proportion of unidentified extractable organofluorine (EOF) observed globally in humans and the environment indicates widespread occurrence of unknown per- and polyfluoroalkyl substances (PFAS). However, efforts to standardize or assess the reproducibility of EOF methods are currently lacking. Here we present the first EOF interlaboratory comparison in water and sludge. Three participants (four organizations) analyzed unfortified and PFAS-fortified ultrapure water, two unfortified groundwater samples, unfortified wastewater treatment plant effluent and sludge, and an unfortified groundwater extract. Participants adopted common sample handling strategies and target lists for EOF mass balance but used in-house combustion ion-chromatography (CIC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. EOF accuracy ranged from 85–101% and 76–109% for the 60 and 334 ng L−1 fluorine (F) – fortified water samples, respectively, with between-laboratory variation of 9–19%, and within-laboratory variation of 3–27%. In unfortified sludge and aqueous samples, between-laboratory variation ranged from 21–37%. The contribution from sum concentrations of 16 individual PFAS (∑PFAS-16) to EOF ranged from 2.2–60% but extended analysis showed that other targets were prevalent, in particular ultra-short-chain perfluoroalkyl acids (e.g. trifluoroacetic acid) in aqueous samples and perfluoroalkyl acid-precursors (e.g. polyfluoroalkyl phosphate diesters) in sludge. The EOF-CIC method demonstrated promising accuracy, robustness and reporting limits but poor extraction efficiency was observed for some targets (e.g. trifluoroacetic acid). [ABSTRACT FROM AUTHOR]

We synthesize current understanding of the magnitudes and methods for assessing human and wildlife exposures to poly‐ and perfluoroalkyl substances (PFAS). Most human exposure assessments have focused on 2 to 5 legacy PFAS, and wildlife assessments are typically limited to targeted PFAS (up to ~30 substances). However, shifts in chemical production are occurring rapidly, and targeted methods for detecting PFAS have not kept pace with these changes. Total fluorine measurements complemented by suspect screening using high‐resolution mass spectrometry are thus emerging as essential tools for PFAS exposure assessment. Such methods enable researchers to better understand contributions from precursor compounds that degrade into terminal perfluoroalkyl acids. Available data suggest that diet is the major human exposure pathway for some PFAS, but there is large variability across populations and PFAS compounds. Additional data on total fluorine in exposure media and the fraction of unidentified organofluorine are needed. Drinking water has been established as the major exposure source in contaminated communities. As water supplies are remediated, for the general population, exposures from dust, personal care products, indoor environments, and other sources may be more important. A major challenge for exposure assessments is the lack of statistically representative population surveys. For wildlife, bioaccumulation processes differ substantially between PFAS and neutral lipophilic organic compounds, prompting a reevaluation of traditional bioaccumulation metrics. There is evidence that both phospholipids and proteins are important for the tissue partitioning and accumulation of PFAS. New mechanistic models for PFAS bioaccumulation are being developed that will assist in wildlife risk evaluations. Environ Toxicol Chem 2021;40:631–657. © 2020 SETAC [ABSTRACT FROM AUTHOR]

Since the detection of per- and polyfluoroalkyl substances (PFAS) in humans and different environmental media in the last two decades, this substance group has attracted a lot of attention as well as increasing concerns. The fluorine mass balance approach, by comparing the levels of targeted PFAS after conversion to fluorine equivalents with those of extractable organic fluorine (EOF), showed the presence of unidentified organofluorine in different environmental samples. Out of the thousands of PFAS in existence, only a very small fraction is included in routine analysis. In recent years, liquid chromatography coupled with tandem-mass spectrometry (LC-MS/MS) has demonstrated the ability to analytically cover a wide spectrum of PFAS. In contrast, conventional extraction methods developed 10 to 15 years ago were only evaluated for a limited number of PFAS. The aim of the present study was to evaluate the advantages and disadvantages of three different extraction methods, adapted from the literatures without further optimization (ion-pair liquid-liquid extraction, solid-phase extraction (SPE), using hydrophilic-lipophilic (HLB) or weak anion exchange (WAX) sorbents), for human biomonitoring of 61 PFAS in serum and placental tissue samples. In addition, levels of EOF were compared among these extraction methods via spiked samples. Results showed that performance, in terms of recovery, differed between the extraction methods for different PFAS; different extraction methods resulted in different EOF concentrations indicating that the choice of extraction method is important for target PFAS and EOF analysis. Results of maternal serum samples, analyzed in two different laboratories using two different extraction methods, showed an accordance of 107.6% (± 21.3); the detected perfluoroalkyl acids (PFAAs) in maternal and cord serum samples were in the range of 0.076 to 2.9 ng/mL. Graphical abstract [ABSTRACT FROM AUTHOR]

Background: Lipoproteins at aberrant levels are known to play a role in cardiovascular disease. The metabolite of the insecticide dichlorodiphenyltrichloroethane (DDT), p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE), physically associates with lipids and accumulates in adipose tissue. Little is known about which lipoproteins associate with p,p'-DDE. An association between p,p'-DDE exposure and altered levels of circulating lipids was assessed in a large human cohort using a detailed analysis of lipoprotein content. Methods: Plasma samples were collected from the subset of 75-year old Swedes in the Prospective Investigation of the Vasculature of Uppsala Seniors (PIVUS) cohort who were not prescribed lipid lowering medication (n = 571). p,p'-DDE concentrations in plasma were measured using high-throughput solid phase extraction and gas chromatography-high resolution mass spectrometry. Analysis of plasma lipoprotein content was performed with nuclear magnetic resonance spectroscopy. Results: Detectable levels of p,p'-DDE were found in the plasma samples of all subjects. Elevated p,p'-DDE levels were associated with increased concentrations of lipoproteins of all diameters, with the exception of high density lipoprotein (HDL) of diameters between 14.3 nm–10.9 nm. Of the lipoprotein constituents, triglycerides were most uniformly associated with elevated p,p'-DDE across lipoproteins. p,p'-DDE was furthermore associated with apolipoprotein B, but not apolipoprotein A1. Conclusions: The positive associations observed between each lipoprotein class and elevated p,p'-DDE support previous data suggesting that p,p'-DDE interacts with lipoproteins within plasma. It is speculated that both physio-chemical and biological mechanisms may explain why p,p'-DDE does not uniformly associate with lipids across lipoproteins. [ABSTRACT FROM AUTHOR]

Ultra-short-chain perfluoroalkyl acids have recently gained attention due to increasing environmental concentrations being observed. The most well-known ultra-short-chain perfluoroalkyl acid is trifluoroacetic acid (TFA) which has been studied since the 1990s. Potential sources and the fate of ultra-short-chain perfluoroalkyl acids other than TFA are not well studied and data reporting their environmental occurrence is scarce. The analytical determination of ultra-short-chain perfluoroalkyl acids is challenging due to their high polarity resulting in low retention using reversed-phase liquid chromatography. Furthermore, recent studies have reported varying extraction recoveries in water samples depending on the water matrix and different methods have been suggested to increase the extraction recovery. The present review gives an overview of the currently used analytical methods and summarizes the findings regarding potential analytical challenges. In addition, the current state of knowledge regarding TFA and other ultra-short-chain perfluoroalkyl acids, namely perfluoropropanoic acid, trifluoromethane sulfonic acid, perfluoroethane sulfonic acid, and perfluoropropane sulfonic acid‚ are reviewed. Both known and potential sources as well as environmental concentrations are summarized and discussed together with their fate and the environmental and human implications. [ABSTRACT FROM AUTHOR]

Owing to the development and adoption of a variety of methods for sampling and identifying microplastics, there is now data showing the presence of microplastics in surface waters from all over the world. The difference between the methods, however, hampers comparisons, and to date, most studies are qualitative rather than quantitative. In order to allow for a quantitative comparison of microplastics abundance, it is crucial to understand the differences between sampling methods. Therefore, a manta trawl and an in situ filtering pump were compared during realistic, but controlled, field tests. Identical microplastic analyses of all replicates allowed the differences between the methods with respect to (1) precision, (2) concentrations, and (3) composition to be assessed. The results show that the pump gave higher accuracy with respect to volume than the trawl. The trawl, however, sampled higher concentrations, which appeared to be due to a more efficient sampling of particles on the sea surface microlayer, such as expanded polystyrene and air-filled microspheres. The trawl also sampled a higher volume, which decreased statistical counting uncertainties. A key finding in this study was that, regardless of sampling method, it is critical that a sufficiently high volume is sampled to provide enough particles for statistical evaluation. Due to the patchiness of this type of contaminant, our data indicate that a minimum of 26 particles per sample should be recorded to allow for concentration comparisons and to avoid false null values. The necessary amount of replicates to detect temporal or spatial differences is also discussed. For compositional differences and size distributions, even higher particle counts would be necessary. Quantitative measurements and comparisons would also require an unbiased approach towards both visual and spectroscopic identification. To facilitate the development of such methods, a visual protocol that can be further developed to fit different needs is introduced and discussed. Some of the challenges encountered while using FTIR microspectroscopic particle identification are also critically discussed in relation to specific compositions found. [ABSTRACT FROM AUTHOR]

Perfluoroalkyl acids (PFAAs) are ubiquitous environmental contaminants and eggs and nestlings of raptors and fish-eating birds often contain high levels of PFAAs. We studied developmental effects of a mixture of ten PFAAs by exposing chicken embryos to 0.5 or 3 μg/g egg of each compound in the mixture. Histological changes of the thyroid gland were noted at both doses and increased expression of mRNA coding for type III deiodinase was found at 0.5 μg/g egg. Serum concentrations of the free fraction of thyroid hormones (T3 and T4) were reduced by the PFAA mixture at 3 µg/g egg, which is in line with a decreased synthesis and increased turnover of thyroid hormones as indicated by our histological findings and the decreased mRNA expression of type III deiodinase. The relative weight of the bursa of Fabricius increased at a dose of 3 μg/g egg in females. The bursa is the site of B-cell development in birds and is crucial for the avian adaptive immune system. Analysis of plasma and liver concentrations of the mixture components showed differences depending on chain length and functional group. Our results highlight the vulnerability of the thyroid hormone and immune systems to PFAAs. [ABSTRACT FROM AUTHOR]

Major point sources of per- and polyfluoroalkyl substances (PFASs) cause ubiquitous spread of PFASs in the environment. In this study, surface water and aquatic invertebrates at three Swedish sites impacted by PFAS point sources were characterized, using homologue, isomer and extractable organofluorine (EOF) profiling as well as estimation of bioaccumulation factors (BAFs) and mass discharge. Two sites were impacted by fire training (sites A and R) and the third by industrial runoff (site K). Mean Σ25PFASs concentration in water was 1920 ng L−1 at site R (n = 3), which was more than 20- and 10-fold higher than those from sites A and K, respectively. PFOS was the most predominant PFAS in all waters samples, constituting 29–79% of Σ25PFAS concentrations. Several branched isomers were detected and they substantially contributed to concentrations in surface water (e.g. 49–78% of ΣPFOS) and aquatic invertebrates (e.g. 15–28% of ΣPFOS). BAFs in the aquatic invertebrates indicated higher bioaccumulation for long chain PFASs and lower bioaccumulation for branched PFOS isomers compared to linear PFOS. EOF mass balance showed that Σ25target PFASs in water could explain up to 55% of EOF at site R. However, larger proportions of EOF (>92%) remained unknown in water from sites A and K. Mass discharges were for the first time estimated for EOF and revealed that high amounts of EOF (e.g. 8.2 g F day−1 at site A) could be transported by water to recipient water bodies relative to Σ25PFASs (e.g. 0.15 g day−1 at site A). Overall, we showed that composition profiling, BAFs and EOF mass balance can improve the characterization of PFASs around point sources. [ABSTRACT FROM AUTHOR]

Plastic is able to sorb environmental pollutants from ambient water and might act as a vector for these pollutants to marine organisms. The potential toxicological effects of plastic-sorbed pollutants in marine organisms have not been thoroughly assessed. In this study, organic extracts from four types of plastic deployed for 9 or 12 months in San Diego Bay, California, were examined for their potential to activate the aryl hydrocarbon receptor (AhR) pathway by use of the H4IIE-luc assay. Polycyclic aromatic hydrocarbons (PAH), including the 16 priority PAHs, were quantified. The AhR-mediated potency in the deployed plastic samples, calculated as bio-TEQ values, ranged from 2.7 pg/g in polyethylene terephthalate (PET) to 277 pg/g in low-density polyethylene (LDPE). Concentrations of the sum of 24 PAHs in the deployed samples ranged from 4.6 to 1068 ng/g. By use of relative potency factors (REP), a potency balance between the biological effect (bio-TEQs) and the targeted PAHs (chem-TEQs) was calculated to 24–170%. The study reports, for the first time, in vitro AhR-mediated potencies for different deployed plastics, of which LDPE elicited the greatest concentration of bio-TEQs followed by polypropylene (PP), PET, and polyvinylchloride (PVC). [ABSTRACT FROM AUTHOR]

Untargeted metabolic profiling of body fluids in experimental animals and humans exposed to chemicals may reveal early signs of toxicity and indicate toxicity pathways. Avian embryos develop separately from their mothers, which gives unique possibilities to study effects of chemicals during embryo development with minimal confounding factors from the mother. In this study we explored blood plasma and allantoic fluid from chicken embryos as matrices for revealing metabolic changes caused by exposure to chemicals during embryonic development. Embryos were exposed via egg injection on day 7 to the environmental pollutant perfluorooctanoic acid (PFOA), and effects on the metabolic profile on day 12 were compared with those caused by GW7647 and rosiglitazone, which are selective agonists to peroxisome-proliferator activated receptor α (PPARα) and PPARγ, respectively. Analysis of the metabolite concentrations from allantoic fluid by Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA) showed clear separation between the embryos exposed to GW7647, rosiglitazone, and vehicle control, respectively. In blood plasma only GW7647 caused a significant effect on the metabolic profile. PFOA induced embryo mortality and increased relative liver weight at the highest dose. Sublethal doses of PFOA did not significantly affect the metabolic profile in either matrix, although single metabolites appeared to be altered. Neonatal mortality by PFOA in the mouse has been suggested to be mediated via activation of PPARα. However, we found no similarity in the metabolite profile of chicken embryos exposed to PFOA with those of embryos exposed to PPAR agonists. This indicates that PFOA does not activate PPAR pathways in our model at concentrations in eggs and embryos well above those found in wild birds. The present study suggests that allantoic fluid and plasma from chicken embryos are useful and complementary matrices for exploring effects on the metabolic profile resulting from chemical exposure during embryonic development. [ABSTRACT FROM AUTHOR]

Temporal trends of perfluoroalkyl substances (PFASs) have been determined in the blood samples from several countries globally including a female population in Sweden recently, yet little is known about the time trends in the blood levels of these compounds in Swedish male populations over recent years. In this study, the fourteen target PFASs consisted of four perfluorosulfonates (PFSAs) and ten perfluorocarboxylates (PFCAs) in the whole blood samples, collected from 153 Swedish elderly men during the period between 2008 and 2010, were analyzed via ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). As the dominant PFASs contaminants in the blood samples, perfluorooctane sulfonate (PFOS) showed the highest geometric mean (GM) at 8.5 ng/mL, ranging from 1.7 to 29 ng/mL, while blood perfluorooctanoic acid (PFOA) contained the GM of 1.8 ng/mL, ranging from 0.35 to 6.4 ng/mL. Both the levels of these two compounds were lower than those determined in the blood samples of Swedish elderly populations derived from the late 1990s. According to the temporal trend analysis, over the three years, the blood levels of PFOS in Swedish male populations declined 16 % per annum, while those of perfluoroundecanoic acid (PFUnDA) increased 6.1 % per annum, which were consistent with those reported previously for the populations from other countries. [ABSTRACT FROM AUTHOR]

Diet and drinking water are suggested to be major exposure pathways for perfluoroalkyl substances (PFASs). In this study, food items and water from Faroe Islands sampled in 2011/2012 were analyzed for 11 perfluoroalkyl carboxylic acids (PFCAs) and 4 perfluoroalkane sulfonic acids (PFSAs). The food samples included milk, yoghurt, crème fraiche, potatoes, fish, and fish feed, and the water samples included surface water and purified drinking water. In total, nine PFCAs and four PFSAs were detected. Generally, the levels of PFAS were in the lower picogram per gram range. Perfluorobutanoic acid was a major contributor to the total PFASs concentration in water samples and had a mean concentration of 750 pg/L. Perfluoroundecanoic acid (PFUnDA) was predominating in milk and wild fish with mean concentrations of 170 pg/g. Perfluorooctane sulfonic acid (PFOS) was most frequently detected in food items followed by PFUnDA, perfluorononanoic acid, and perfluorooctanoic acid (PFOA). Levels of PFUnDA and PFOA exceeded those of PFOS in milk and fish samples. Prevalence of long-chain PFCAs in Faroese food items and water is confirming earlier observations of their increase in Arctic biota. Predominance of short-chain and long-chain homologues indicates exposure from PFOS and PFOA replacement compounds. [ABSTRACT FROM AUTHOR]

Previous reports show that professional ski waxers have elevated blood levels of perfluorinated substances (PFAS) such as perfluorooctanoate (PFOA) and are exposed to very high concentrations of PFAS in air during ski waxing. Aerosol exposure increases the risk of cardiovascular disease, and PFOA is a potential hormonal disruptor and carcinogen, and can affect the fatty acid metabolism. Animal studies have shown that 8:2 FTOH can undergo biotransformation to PFOA. For the first time, this study presents an occupational scenario of professional ski waxers who are exposed to extremely high dust levels as well as per- and polyfluorinated compounds. Personal and fixed measurements of total aerosol, inhalable and respirable fractions were performed during World Cup events 2007-2010. The occupational exposure limit (OEL) is exceeded in 37% of the personal measurements with concentrations up to 15 mg m-3 in air. There are differences between personal and area total aerosol concentrations with levels from personal measurements twice as high as those from the area measurements. The personal levels for FTOH ranged up to 996 μg m-3 (mean = 114 mg m-3) and for PFOA up to 4.89 μg m-3 (mean = 0.53 μg m-3) in ENV+ sorbent samples as compared to the general exposure levels from air reaching only low ng m-3 (<30 ng m-3) levels. FTOHs were not detected in aerosols but PFOA showed an average level of 12 μg m-3 (range = 1.2-47 μg m-3). The ski waxers' exposure to paraffin fumes and PFAS is not in compliance with the occupational exposure standards and by far exceed the general populations' exposure. Preventive measures must be taken to minimize the exposure in this occupational group. [ABSTRACT FROM AUTHOR]

Recent developments, improvements, and trends in the ultra-trace determination of per- and polyfluoroalkyl substances (PFASs) in environmental and human samples are highlighted and the remaining challenges and uncertainties are outlined and discussed. Understanding the analytical implications of such things as adsorption of PFASs to surfaces, effects of differing matrices, varying PFAS isomer response factors, potential bias effects of sampling, sample preparation, and analysis is critical to measuring highly fluorinated compounds at trace levels. These intricate analytical issues and the potential consequences of ignoring to deal with them correctly are discussed and documented with examples. Isomer-specific analysis and the development of robust multi-chemical methods are identified as topical trends in method development for an ever-increasing number of PFASs of environmental and human interest. Ultimately, the state-of-the-art of current analytical method accuracy is discussed on the basis of results from interlaboratory comparison studies. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The article presents the study which explores the distribution of perfluorinated compounds (PFCs) levels on human liver and breast milk in Catalonia, Spain. Samples were analyzed by solid-phase extraction and ultra-performance liquid chromatography tandem mass spectrometry. It notes that liver samples accumulated high PFCs and perfluorooctanesulfonate (PFOS) concentration. It was observed in the study that PFCs are bound to the protein fraction in blood.

The article focuses on a study about the role of Peroxisome proliferator-activated receptor &#x03B (PPAR &#x03B); in hepatobiliary injuries in mice induced by ammonium perfluorooctanoic acid (PFOA). Major hepatocellular damage and minor cholangiopathy cause by PFOA in wild type mice compared to treated PPAR&#x03B-null mice in which fat was accumulated, severe cholangiopathy and hepatocellular damage was observed. Results reported that PPAR&#x03B is significant against PFOA and biliary injury.

BACKGROUND: Only limited data exist on lactation as an exposure source of persistent perfluorinated chemicals (PFCs) for children. OBJECTIVES: 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. RESULTS: 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. DISCUSSION: 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 (r² = 0.7) and PFHxS (r² = 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. CONCLUSION: 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. [ABSTRACT FROM AUTHOR]

Background: It has previously been reported that the environmental contaminants perfluoroalkyl substances (PFASs) are linked to atherosclerosis in cross-sectional studies. Since cross-sectional studies could be subject to reverse causation, the purpose of this study was to analyze if the longitudinal changes in PFASs during a 10-year follow-up were related to the change in carotid artery intima-media thickness (IMT, ultrasound) during the same period.Methods: In the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, 1016 individuals were investigated at age 70; 826 of them were reinvestigated at age 75 and 602 at age 80 years. Eight different PFASs were measured in plasma by ultra-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), and IMT was measured at all three time points. Random-effects mixed regression models were used to examine the associations over time.Results: IMT increased 0.058 mm during the 10-year period (p < 0.0001). Following adjustment for baseline values of PFASs (age 70) and sex, the changes in plasma levels of 6 of the 8 measured PFASs were significantly related to the change in IMT over the 10-year follow-up period in a positive fashion (p < 0.0062 using Bonferroni correction for 8 tests). Further adjustment for traditional cardiovascular (CV) risk factors (HDL and LDL cholesterol, smoking, systolic blood pressure, statin use, fasting glucose and serum triglycerides) affected these relationships only marginally.Conclusion: The change in plasma levels of several PFASs during 10 years was positively related to increase in IMT seen during the same period, giving prospective evidence that PFASs might interfere with the atherosclerotic process. [ABSTRACT FROM AUTHOR]