Analysis of a homologous series of perfluorocarboxylates from American Red Cross adult blood donors, 2000-2001 and 2006

The purpose of this study was to determine the concentration trends of a nine-target-analyte homologous series of perfluorocarboxylates from six American Red Cross adult blood donor centers. A total of 645 serum and 600 plasma samples were obtained in 2000-2001 and 2006, respectively, with samples stratified for each 10-year (20-69) age- and sex-group per each location. Samples were extracted by protein precipitation and quantified by using tandem mass spectrometry. The nine perfluorocarboxylates were perfluorobutanoate (PFBA, C(3)F(7)CO(2)(-)), perfluoropentanoate (PFPeA, C(4)F(9)CO(2)(-)), perfluorohexanoate (PFHxA, C(5)F(11)CO(2)(-)), perfluoroheptanoate (PFHpA, C(6)F(13)CO(2)(-)), perfluorooctanoate (PFOA, C(7)F(15)CO(2)(-)), perfluorononanoate (PFNA, C(8)F(17)CO(2)(-)), perfluorodecanoate (PFDA, C(9)F(19)CO(2)(-)), perfluoroundecanoate (PFUnA,C(10)F(21)CO(2)(-)), and perfluorododecanoate (PFDoA, C(11)F(23)CO(2)(-)). The majority of measurements were less than the lower limit of quantitation for PFPeA, PFHxA, and PFDoA. For the remaining targeted analytes, the geometric mean serum and plasma concentrations (ng/mL) for 2000-2001 and 2006 were, respectively, as follows: PFBA 2.61 vs 0.33, PFHpA 0.13 vs 0.09, PFOA 4.70 vs 3.44, PFNA 0.57 vs 0.97, PFDA 0.16 vs 0.34, and PFUnA 0.10 vs 0.18. Estimates of the 95th percent tolerance limits (ng/mL) were as follows: PFBA 5.3 vs 1.4, PFHpA 0.4 vs 0.4, PFOA 12.3 vs 7.7, PFNA 1.4 vs 2.2, PFDA 0.4 vs 0.8, and PFUnA 0.3 vs 0.5. Important observations were the decline in PFBA and increase in PFNA, PFDA, and PFUnA concentrations between 2000-2001 and 2006. The longer chain length perfluorocarboxylates were also highly correlated with each other.     

Perfluorooctanesulfonate and related fluorochemicals in human blood samples from China

Perfluorooctanesulfonylfluoride (POSF)-based compounds have been manufactured and used in a variety of industrial applications. These compounds degrade to perfluorooctanesulfonate (PFOS) which is regarded as a persistent end-stage metabolite and is found to accumulate in tissues of humans and wildlife. PFOS, perfluorohexanesulfonate (PFHxS), perfluorooctanoate (PFOA), and perfluorooctanesulfonamide (PFOSA) have been found in human sera from the United States. In this study, concentrations of PFHxS, perfluorobutanesulfonate (PFBS), PFOS, perfluorohexanoic acid (PFHxA), PFOA, perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), and PFOSA were measured in 85 samples of whole human blood collected from nine cities (eight provinces) in China, including Shenyang (Liaoning), Beijing (Hebei), Zhengzhou (Henan), Jintan (Jiangsu), Wuhan (Hubei), Zhoushan (Zhejiang), Guiyang (Guizhou), Xiamen (Fujian), and Fuzhou (Fujian). Among the 10 perfluorinated compounds (PFCs) measured, PFOS was the predominant compound. The mean concentration of PFOS was greatest in samples collected from Shenyang (79.2 ng/mL) and least in samples from Jintan (3.72 ng/mL). PFHxS was the next most abundant perfluorochemical in the samples. No age-related differences in the concentrations of PFOA, PFOS, PFOSA, and PFHxS were observed. Gender-related differences were found,with males higher for PFOS and PFHxS, and females higher in PFUnDA. Concentrations of PFHxS were positively correlated with those of PFOS, while concentrations of PFNA, PFDA, and PFUnDA were positively correlated with those of PFOA. There were differences in the concentration profiles (percentage composition) of various PFCs in the samples among the nine cities.     

基于液相色谱-串联质谱法的纺织品中痕量全氟化合物的测定

采用超声法提取纺织品中的全氟化合物。以C18为分析柱,甲醇-5 mmol/L乙酸铵为梯度洗脱淋洗液, 13 min内即可分离全氟己酸(PFHxA),全氟辛酸(PFOA),全氟壬酸(PFNA),全氟癸酸(PFDA),全氟十一酸(PFuDA),全氟十二酸(PFDoA), 全氟丁烷磺酸(PFBS),全氟己烷磺酸(PFHxS),全氟辛烷磺酸(PFOS),全氟癸烷磺酸(PFDS) 10种分析物。以313.1/268.9,412.9/368.9,462.9/418.9,512.7/468.9,562.7/518.9,612.8/568.9,298.8/99,399.2/99,498.8/99,599/99分别对PFHxA,PFOA,PFNA,PFDA,PFuDA,PFDoA,PFBS,PFHxS,PFOS,PFDS进行监控和定量分析。利用同位素内标法进行定量,线性范围和添加回收率分别为0.5～10 µg/m2、84.6%～111.8%,检出限为0.5 µg/m2,低于欧盟指定针对纺织品1 µg/m2 的限定。结果表明,本方法准确、快速,并成功用于20种纺织品实样的检测。     

Perfluorinated Alkyl Acids in Blood Serum from Primiparous Women in Sweden: Serial Sampling during Pregnancy and Nursing, And Temporal Trends 1996-2010

We investigated temporal trends of blood serum levels of 13 perfluorinated alkyl acids (PFAAs) and perfluorooctane sulfonamide (FOSA) in primiparous women (N = 413) from Uppsala County, Sweden, sampled 3 weeks after delivery 1996-2010. Levels of the short-chain perfluorobutane sulfonate (PFBS) and perfluorohexane sulfonate (PFHxS) increased 11%/y and 8.3%/y, respectively, and levels of the long-chain perfluorononanoate (PFNA) and perfluorodecanoate (PFDA) increased 4.3%/y and 3.8%/y, respectively. Concomitantly, levels of FOSA (22%/y), perfluorooctane sulfonate (PFOS, 8.4%/y), perfluorodecane sulfonate (PFDS, 10%/y), and perfluorooctanoate (PFOA, 3.1%/y) decreased. Thus, one or several sources of exposure to the latter compounds have been reduced or eliminated, whereas exposure to the former compounds has recently increased. We explored if maternal levels of PFOS, PFOA, and PFNA during the early nursing period are representative for the fetal development period, using serial maternal serum samples, including cord blood (N = 19). PFAA levels in maternal serum sampled during pregnancy and the nursing period as well as in cord blood were strongly correlated. Strongest correlations between cord blood levels and maternal levels were observed for maternal serum sampled shortly before or after the delivery (r = 0.70-0.89 for PFOS and PFOA). A similar pattern was observed for PFNA, although the correlations were less strong due to levels close to the method detection limit in cord blood.     

Is fish a major source of fluorinated surfactants and repellents in humans living on the Baltic Coast?

Concentrations of 19 perfluorochemicals have been quantified in human blood and in some marine food resources from the region of the Gulf of Gda?sk at the Baltic Sea south coast in Poland. We indicate that in addition to PFOS and PFOA, a further 8 perfluorochemicals bioaccumulate in the human body. Food chain is an important route of exposure for all 10 perfluoroalkyl compounds detected in nonoccupationally exposed humans. Individuals who declared to have a high fish intake in their diet (mainly Baltic fish) on average contained the highest load of all 10 fluorochemicals when compared with the other human subpopulations. Baltic seafood has been found to highly influence human body burden of PFHxS, PFOS, PFOSA, PFHxA, PFHpA, PFNA, PFDA, PFUnDA, and PFDoDA, and to a lesser extent PFOA.     

Decline in perfluorooctanesulfonate and other polyfluoroalkyl chemicals in American Red Cross adult blood donors, 2000-2006

In 2000, 3M Company, the primary global manufacturer, announced a phase-out of perfluorooctanesulfonyl fluoride (POSF, C8F17SO2F)-based materials after perfluorooctanesulfonate (PFOS, C8F17SO3-) was reported in human populations and wildlife. The purpose of this study was to determine whether PFOS and other polyfluoroalkyl concentrations in plasma samples, collected in 2006 from six American Red Cross adult blood donor centers, have declined compared to nonpaired serum samples from the same locations in 2000-2001. For each location, 100 samples were obtained evenly distributed by age (20-69 years) and sex. Analytes measured, using tandem mass spectrometry, were PFOS, perfluorooctanoate (PFOA), perfluorohexanesulfonate (PFHxS), perfluorobutanesulfonate (PFBS), N-methyl perfluorooctanesulfonamidoacetate (Me-PFOSA-AcOH), and N-ethyl perfluorooctanesulfonamidoacetate (Et-PFOSA-AcOH). The geometric mean plasma concentrations were for PFOS 14.5 ng/mL (95% CI 13.9-15.2), PFOA 3.4 ng/ mL (95% CI 3.3-3.6), and PFHxS 1.5 ng/mL (95% CI 1.4-1.6). The majority of PFBS, Me-PFOSA-AcOH, and Et-PFOSA-AcOH concentrations were less than the lower limit of quantitation. Age- and sex-adjusted geometric means were lower in 2006 (approximately 60% for PFOS, 25% for PFOA, and 30% for PFHxS) than those in 2000-2001. The declines for PFOS and PFHxS are consistent with their serum elimination half-lives and the time since the phase-out of POSF-based materials. The shorter serum elimination half-life for PFOA and its smaller percentage decline than PFOS suggests PFOA concentrations measured in the general population are unlikely to be solely attributed to POSF-based materials. Direct and indirect exposure sources of PFOA could include historic and ongoing electrochemical cell fluorination (ECF) of PFOA, telomer production of PFOA, fluorotelomer-based precursors, and other fluoropoly-mer production.     

Occurrence and sources of perfluorinated surfactants in rivers in Japan

We analyzed perfluorinated surfactants (PFSs) in 20 river samples and 5 wastewater secondary effluent samples in Japan to reveal their occurrence and sources. Nine PFS species were determined: perfluorooctanesulfonate (PFOS), perfluorooctane sulfonamide (FOSA), perfluoroheptanoate (PFHpA), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), perfluorodecanoate (PFDA), perfluoroundecanoate (PFUA), perfluorododecanoate (PFDDA), and perfluorotridecanoate (PFTDA). PFSs were detected in all rivers, revealing nationwide contamination of rivers. In particular, 11 out of 20 river samples exceeded New Jersey guidance for PFOA in drinking water (40 ng/L). PFOS, PFHpA, PFOA, and PFNA were major species in Japan. Concentrations of PFOS, PFHpA, and PFNA in rivers were strongly correlated with population density, suggesting that the chemicals were derived from urban activities. PFOA showed a significant but weak correlation. We used crotamiton, a marker of sewage effluent, for further source analysis. Concentrations of PFOS, PFHpA, and PFNAwere strongly correlated with those of crotamiton, and plots of secondary effluents fell near the regression lines of rivers, indicating that the PFOS, PFHpA, and PFNA in rivers were derived from sewage effluent. On the other hand, PFOA was found at remarkably high levels (54-192 ng/L) in seven river samples containing low levels of crotamiton, suggesting that it was derived from nonsewage point sources, as well as sewage effluent. The total fluxes of sewage-derived PFOS, PFHpA, PFOA, and PFNA from Japan were estimated to be 3.6, 2.6, 5.6, and 2.6 t/year, respectively. This is the first report to identify PFOA in several rivers, derived from nonsewage point sources, by using a marker of sewage effluent.     

Temporal and spatial trends of perfluorinated compounds in ringed seal (Phoca hispida) from Greenland

Perfluorinated compounds (PFCs), such as perfluorooctane sulfonate (PFOS) and related compounds, have been identified as global pollutants and have shown their bioaccumulation into higher trophic levels in the food chain. PFCs have been found in remote areas far from sources, such as the Arctic. In this study spatial and temporal trends in the concentrations of selected PFCs were measured using archived liver samples of ringed seal (Phoca hispida) from East and West Greenland. The samples were collected in four different years at each location, between 1986 and 2003 in East Greenland and between 1982 and 2003 in West Greenland. PFOS was the major contributor to the burden of PFCs in samples, followed by perfluoroundecanoic acid (PFUnA). Perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) were also detected in most samples. Perfluorohexane sulfonate (PFHxS) and perfluorooctane sulfonamide (PFOSA) were only found sporadically. Perfluorooctanoic acid was not found in detectable concentrations in any sample. Regression analysis of logarithmic transformed PFOS, PFDA, and PFUnA median concentrations indicated a significant temporal trend with increasing concentrations at both locations. A spatial trend in PFOS concentrations (ANOVA, p < 0.0001) was observed between the two sampling locations, with significantly higher concentrations in seals from East Greenland.     

Perfluorooctanesulfonate and related fluorochemicals in human blood from several countries

Perfluorooctanesulfonyl fluoride based compounds have been used in a wide variety of consumer products, such as carpets, upholstery, and textiles. These compounds degrade to perfluorooctanesulfonate (PFOS), a persistent metabolite that accumulates in tissues of humans and wildlife. Previous studies have reported the occurrence of PFOS, perfluorohexanesulfonate (PFHxS), perfluorooctanoate (PFOA), and perfluorooctanesulfonamide (PFOSA) in human sera collected from the United States. In this study, concentrations of PFOS, PFHxS, PFOA, and PFOSA were measured in 473 human blood/serum/plasma samples collected from the United States, Colombia, Brazil, Belgium, Italy, Poland, India, Malaysia, and Korea. Among the four perfluorochemicals measured, PFOS was the predominant compound found in blood. Concentrations of PFOS were the highest in the samples collected from the United States and Poland (>30 ng/mL); moderate in Korea, Belgium, Malaysia, Brazil, Italy, and Colombia (3 to 29 ng/mL); and lowest in India (<3 ng/mL). PFOA was the next most abundant perfluorochemical in blood samples, although the frequency of occurrence of this compound was relatively low. No age- or gender-related differences in the concentrations of PFOS and PFOA were found in serum samples. The degree of association between the concentrations of four perfluorochemicals varied, depending on the origin of the samples. These results suggested the existence of sources with varying levels and compositions of perfluorochemicals, and differences in exposure patterns to these chemicals, in various countries. In addition to the four target fluorochemicals measured, qualitative analysis of selected blood samples showed the presence of other perfluorochemicals such as perfluorodecanesulfonate (PFDS), perfluoroheptanoic acid (PFHpA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorododecanoic acid (PFDoA), and perfluoroundecanoic acid (PFUnDA) in serum samples, at concentrations approximately 5- to 10-fold lower than the concentration of PFOS. Further studies should focus on identifying sources and pathways of human exposure to perfluorochemicals.     

Trends in exposure to polyfluoroalkyl chemicals in the U.S. Population: 1999-2008

Since 2002, practices in manufacturing polyfluoroalkyl chemicals (PFCs) in the United States have changed. Previous results from the National Health and Nutrition Examination Survey (NHANES) documented a significant decrease in serum concentrations of some PFCs during 1999-2004. To further assess concentration trends of perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), perfluorohexane sulfonate (PFHxS), and perfluorononanoate (PFNA), we analyzed 7876 serum samples collected from a representative sample of the general U.S. population ≥12 years of age during NHANES 1999-2008. We detected PFOS, PFOA, PFNA, and PFHxS in more than 95% of participants. Concentrations differed by sex regardless of age and we observed some differences by race/ethnicity. Since 1999-2000, PFOS concentrations showed a significant downward trend, because of discontinuing industrial production of PFOS, but PFNA concentrations showed a significant upward trend. PFOA concentrations during 1999-2000 were significantly higher than during any other time period examined, but PFOA concentrations have remained essentially unchanged during 2003-2008. PFHxS concentrations showed a downward trend from 1999 to 2006, but concentrations increased during 2007-2008. Additional research is needed to identify the environmental sources contributing to human exposure to PFCs. Nonetheless, these NHANES data suggest that sociodemographic factors may influence exposure and also provide unique information on temporal trends of exposure.     

Human dietary exposure to perfluoroalkyl substances in Catalonia, Spain. Temporal trend

In this study, we assessed the levels of 18 perfluoroalkyl substances (PFASs) in the most widely consumed foodstuffs in Catalonia, Spain, as well as the total dietary intake of these compounds. Forty food items were analysed. Only perfluoropentanoic acid (PFPeA), perfluorohexadecanoic acid (PFHxDA) and perfluorooctanoicdecanoic acid (PFOcDA) were not detected in any sample. Perfluorooctane sulfonate (PFOS) was the compound found in the highest number of samples (33 out of 80), followed by perfluorooctanoic acid (PFOA), perfluoroheptanoic acid (PFHpA), perfluorohexane sulfonic acid (PFHxS), perfluorodecanoic acid (PFDA) and perfluorodecane sulfonic acid (PFDS). Fish and shellfish was the food group in which more PFASs were detected and where the highest PFAS concentrations were found. The highest dietary intakes corresponded to children, followed by male seniors, with values of 1787 and 1466ng/day, respectively. For any of the age/gender groups of the population, the Tolerable Daily Intakes (TDIs) recommended by the EFSA were not exceeded. In general terms, PFAS levels found in the current study are lower than the concentrations recently reported in other countries.     

Perfluorinated acids in Arctic snow: new evidence for atmospheric formation

Perfluorinated acids (PFAs) are ubiquitously found in water and biota, including remote regions such as the High Arctic. Under environmental conditions, PFAs exist mainly as anions and are not expected to be subject to long-range atmospheric transport in the gas phase. Fluorinated telomer alcohols (FTOHs) are volatile and can be atmospherically oxidized to form perfluorocarboxylic acids. Analogously, fluorosulfamido alcohols can be oxidized to form perfluorooctane sulfonate (PFOS). High Arctic ice caps experience contamination solely from atmospheric sources. By examining concentrations of PFAs in ice cap samples, it is possible to determine atmospheric fluxes to the Arctic. Ice samples were collected from high Arctic ice caps in the spring of 2005 and 2006. Samples were concentrated using solid-phase extraction and analyzed by LC-MS-MS. PFAs were observed in all samples, dating from 1996 to 2005. Concentrations were in the low-mid pg L(-1) range and exhibited seasonality, with maximum concentrations in the spring-summer. The presence of perfluorodecanoic acid (PFDA) and perfluoroundecanoic acid (PFUnA) on the ice cap was indicative of atmospheric oxidation as a source. Ratios of PFAs to sodium concentrations were highly variable, signifying PFA concentrations on the ice cap were unrelated to marine chemistry. Fluxes of the PFAs were estimated to the area north of 65 degrees N for the 2005 season, which ranged from 114 to 587 kg year(-1) for perfluorooctanoic acid (PFOA), 73 to 860 kg year(-1) for perfluorononanoic acid (PFNA), 16 to 84 kg year(-1) for PFDA, 26 to 62 kg year(-1) for PFUnA, and 18 to 48 kg year(-1) for PFOS. The PFOA and PFNA fluxes agreed with FTOH modeling estimations. A decrease in PFOS concentrations through time was observed, suggesting a fast response to changes in production. These data suggest that atmospheric oxidation of volatile precursors is a primary source of PFAs to the Arctic.     

Health risks in infants associated with exposure to perfluorinated compounds in human breast milk from Zhoushan, China

Recent studies have reported the ubiquitous distribution of perfluorinated compounds (PFCs), especially perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA), in wildlife and human whole blood or serum. In 2003 a solid phase extraction method was developed, which allowed the measurement of PFCs in human breast milk. In the present study, PFCs in samples of human breast milk from 19 individuals from Zhoushan, China, were analyzed by modifying a previously established method, based on weak-anion exchange extraction. PFOS and PFOA were the two dominant chemicals detected in all the milk samples. Concentrations of PFOS and PFOA ranged from 45 to 360 ng/L and 47 to 210 ng/L, respectively. The maximum concentrations of other PFCs were 100 ng/L for perfluorohexanesulfonate (PFHxS), 62 ng/L for perfluorononanoate (PFNA), 15 ng/L for perfluorodecanoate (PFDA) and 56 ng/L for perfluoroundecanoate (PFUnDA). Statistically significant correlations between various PFCs suggested a common exposure source to humans. No statistically significant correlation was found between concentrations of either PFOS or PFOA and maternal age, weight, or infant weight. Rate of consumption of fish was found to be positively correlated with PFNA, PFDA, and PFUnDA concentrations. Daily intake of PFOS for the child via breast milk with greater PFOS concentrations exceeded the predicted conservative reference dose in 1 of 19 samples, indicating that there may be a small potential risk of PFOS for the infants in Zhoushan via the consumption of breast milk.     

Use of newborn screening program blood spots for exposure assessment: declining levels of perluorinated compounds in New York State infants

Temporal biomonitoring studies can assess changes in population exposures to contaminants, but collection of biological specimens with adequate representation and sufficient temporal resolution can be resource-intensive. Newborn Screening Programs (NSPs) collect blood as dried spots on filter paper from nearly all infants born in the United States (U.S.). In this study, we investigated the use of NSP blood spots for temporal biomonitoring by analyzing perfluorooctane sulfonate (PFOS), perfluorooctane sulfonamide (PFOSA), perfluorohexane sulfonate (PFHxS), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) in 110 New York State (NYS) NSP blood spot composite specimens collected between 1997 and 2007, representing a total of 2640 infants. All analytes were detected in > or =90% of the specimens. Concentrations of PFOS, PFOSA, PFHxS, and PFOA exhibited significant exponential declines after the year 2000, coinciding with the phase-out in PFOS production in the U.S. Calculated disappearance half-lives for PFOS, PFHxS, and PFOA (4.4, 8.2, and 4.1 years, respectively) were similar to biological half-lives reported for retired fluorochemical workers. Our results suggest sharp decreases in perinatal exposure of NYS infants to PFOS, PFOSA, PFHxS, and PFOA and demonstrate, for the first time, the utility of NSP blood spots for assessment of temporal trends in exposure.     

Tissue distribution of perfluorinated chemicals in harbor seals (Phoca vitulina) from the Dutch Wadden Sea

Perfluorinated acids (PFAs) are today widely distributed in the environment, even in remote arctic areas. Recently, perfluorooctane sulfonate (PFOS) has been identified in marine mammals all over the world, but information on the compound-specific tissue distribution remains scarce. Furthermore, although longer perfluorinated carboxylic acids (PFCAs) are used in industry and were shown to cause severe toxic effects, still little is known on potential sources or their widespread distribution. In this study, we report for the first time on levels of longer chain PFCAs, together with some short chain PFAs, perfluorobutane sulfonate (PFBS) and perfluorobutanoate (PFBA), in liver, kidney, blubber, muscle, and spleen tissues of harbor seals (Phoca vitulina) from the Dutch Wadden Sea. PFOS was the predominant compound in all seal samples measured (ranging from 89 to 2724 ng/g wet weight); however, large variations between tissues were monitored. Although these are preliminary results, it is, to our knowledge, the first time that PFBS could be found at detectable concentrations (2.3 +/- 0.7 ng/g w wt) in environmental samples. PFBS was only detected in spleen tissue. PFCA levels were much lower than PFOS concentrations. The dominant PFCA in all tissues was PFNA (perfluorononanoic acid), and concentrations generally decreased in tissues for all other PFCA homologues with increasing chain length. No clear relationship between PFOS levels in liver and kidney was observed. Furthermore, hepatic PFDA (perfluorodecanoic acid) levels increased with increasing body length, but in kidney tissue, PFDA levels showed an inverse relationship with increasing body length. These data suggest large differences in tissue distribution and accumulation patterns of perfluorinated compounds in marine organisms.     

Exposure of an adult population to perfluorinated substances using duplicate diet portions and biomonitoring data

Because dietary intake is supposed to be an important route of human exposure we quantified the dietary intake of perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), perfluorohexane sulfonate (PFHxS), perfluorohexanoate (PFHxA), and perfluorooctane sulfonamide (PFOSA) using 214 duplicate diet samples. The study was carried out with a study population of 15 female and 16 male healthy subjects aged 16-45 years. The participants collected daily duplicate diet samples over seven consecutive days in 2005. Duplicate samples were homogenized and their ultrasonic extracts were cleaned up by SPE and subjected to HPLC-ESI-MS/MS. In addition, individual intakes were estimated based on blood levels of PFOS and PFOA using a pharmacokinetic model. Blood samples were collected once during the sampling period. The median (90th percentile) daily dietary intake of PFOS and PFOA was 1.4 ng/kg b.w. (3.8 ng/kg b.w.) and 2.9 ng/kg b.w. (8.4 ng/kg b.w.), respectively. PFHxS and PFHxA could be detected only in some samples above detection limit with median (maximum) daily intakes of 2.0 ng/kg b.w. (4.0 ng/kg b.w.) and 4.3 ng/kg b.w. (9.2 ng/kg b.w.), respectively. Because PFOSA could not be detected above the limit of detection of 0.2 ng/g f.w. this indirect route of exposure seems to be of less significance. Overall, the results of this study demonstrate that the German population is exposed to PFOS and PFOA, but the median dietary intake did not reach the recommended tolerable daily intake by far. Biomonitoring data predict an exposure in a comparable range. We suppose that, normally, food intake is the main source of exposure of the general population to PFOS and PFOA.     

Levels of 12 perfluorinated chemicals in pooled australian serum, collected 2002-2003, in relation to age, gender, and region

Pooled serum samples from 3802 Australian residents were analyzed for four perfluoroalkylsulfonates, seven perfluoroalkylcarboxylates, and perfluorooctanesulfonamide (PFOSA). Serum was collected from men and women of five different age groups and from rural and urban regions in Australia. The highest mean concentration was obtained for perfluorooctane sulfonate (PFOS, 20.8 ng/mL) followed by perfluorooctanoic acid (PFOA, 7.6 ng/mL), perfluorohexane sulfonate (PFHxS, 6.2 ng/mL), perfluorononanoic acid (PFNA, 1.1 ng/mL), and PFOSA (0.71 ng/mL). Additional four PFCs were detected in 5-18% of the samples at concentrations near the detection limits (0.1-0.5 ng/mL). An increase in PFOS concentration with increasing age in both regions and genders was observed. The male pool levels of some of the age groups compared to females were higherfor PFOS, PFOA, and PFHxS. In contrast, PFNA concentrations were higher in the female pools. No substantial difference was found in levels of PFCs between the urban and rural regions. The levels are equal or higher than previously reported serum levels in Europe and Asia but lower compared to the U.S.A. These results suggest that emissions from production in the Northern Hemisphere are of less importance for human exposure.     

Impact of treatment processes on the removal of perfluoroalkyl acids from the drinking water production chain

The behavior of polyfluoralkyl acids (PFAAs) from intake (raw source water) to finished drinking water was assessed by taking samples from influent and effluent of the several treatment steps used in a drinking water production chain. These consisted of intake, coagulation, rapid sand filtration, dune passage, aeration, rapid sand filtration, ozonation, pellet softening, granular activated carbon (GAC) filtration, slow sand filtration, and finished drinking water. In the intake water taken from the Lek canal (a tributary of the river Rhine), the most abundant PFAA were PFBA (perfluorobutanoic acid), PFBS (perfluorobutane sulfonate), PFOS (perfluorooctane sulfonate), and PFOA (perfluorooctanoic acid). During treatment, longer chain PFAA such as PFNA (perfluorononanoic acid) and PFOS were readily removed by the GAC treatment step and their GAC effluent concentrations were reduced to levels below the limits of quantitation (LOQ) (0.23 and 0.24 ng/L for PFOS and PFNA, respectively). However, more hydrophilic shorter chain PFAA (especially PFBA and PFBS) were not removed by GAC and their concentrations remained constant through treatment. A decreasing removal capacity of the GAC was observed with increasing carbon loading and with decreasing carbon chain length of the PFAAs. This study shows that none of the treatment steps, including softening processes, are effective for PFAA removal, except for GAC filtration. GAC can effectively remove certain PFAA from the drinking water cycle.The enrichment of branched PFOS and PFOA isomers relative to non branched isomers during GAC filtration was observed during treatment. The finished water contained 26 and 19 ng/L of PFBA and PFBS. Other PFAAs were present in concentrations below 4.2 ng/L The concentrations of PFAA observed in finished waters are no reason for concern for human health as margins to existing guidelines are sufficiently large.     

Association of Perfluorooctanoic Acid with HDL Cholesterol and Circulating miR-26b and miR-199-3p in Workers of a Fluorochemical Plant and Nearby Residents

Perfluoroalkyl chemicals (PFCs) are stable man-made compounds with many industrial and commercial uses. Concern has been raised that they may exert deleterious effects, especially on lipid regulation. We aimed to assess exposure to perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and seven other PFCs in occupational workers from a fluorochemical plant and nearby community residents, and to investigate the association between PFOA and serum biomarkers. Serum biomarkers included not only biochemical parameters, such as lipids and enzymes, but also circulating microRNAs (miRNAs). Samples were analyzed by high-pressure liquid chromatography/tandem mass spectrometry (HPLC-MS/MS). Circulating miRNA levels were detected by quantitative polymerase chain reaction (PCR). Analyses were conducted by correlation and linear regression. We detected PFOS, PFOA, perfluorohexane sulfonate (PFHxS), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) in all samples. The median levels of serum PFOA and PFOS were 284.34 ng/mL and 34.16 ng/mL in residents and 1635.96 ng/mL and 33.46 ng/mL in occupational participants, respectively. To our knowledge, we found for the first time that PFOA was negatively associated with high-density lipoprotein cholesterol (HDL-C) in workers using linear regression after adjusting for potential confounders. Circulating miR-26b and miR-199a-3p were elevated with serum concentration of PFOA. Although the limitations of small sample size and the cross-sectional nature of the current study constrained causal inferences, the observed associations between PFOA and these serum biomarkers warrant further study.     

Oxidative conversion as a means of detecting precursors to perfluoroalkyl acids in urban runoff

A new method was developed to quantify concentrations of difficult-to-measure and unidentified precursors of perfluoroalkyl carboxylic (PFCA) and sulfonic (PFSA) acids in urban runoff. Samples were exposed to hydroxyl radicals generated by thermolysis of persulfate under basic pH conditions and perfluoroalkyl acid (PFAA) precursors were transformed to PFCAs of related perfluorinated chain length. By comparing PFCA concentrations before and after oxidation, the concentrations of total PFAA precursors were inferred. Analysis of 33 urban runoff samples collected from locations around the San Francisco Bay, CA indicated that PFOS (2.6-26 ng/L), PFOA (2.1-16 ng/L), and PFHxA (0.9-9.7 ng/L) were the predominant perfluorinated compounds detected prior to sample treatment. Following oxidative treatment, the total concentrations of PFCAs with 5-12 membered perfluoroalkyl chains increased by a median of 69%, or between 2.8 and 56 ng/L. Precursors that produced PFHxA and PFPeA upon oxidation were more prevalent in runoff samples than those that produced PFOA, despite lower concentrations of their corresponding perfluorinated acids prior to oxidation. Direct measurements of several common precursors to PFOS and PFOA (e.g., perfluorooctanesulfonamide and 8:2 fluorotelomer sulfonate) accounted for less than 25% of the observed increase in PFOA, which increased by a median value of 37%. Exposure of urban runoff to sunlight, advanced oxidation processes, or microbes could result in modest, but measurable, increases in concentrations of PFCAs and PFSAs.