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Understanding sorption of PFOA on soil particles is crucial to evaluate its environmental risk. Here, sorption of PFOA onto ten agricultural soils was examined. The influence of soil physico-chemical properties on PFOA sorption was investigated. The sorption rate of PFOA followed a pseudo-second-order kinetics. Isotherm data of PFOA sorption was fitted with both Freundlich and linear models and the latter fitted better. The sorption-desorption of PFOA onto ten soil samples depended on soil organic carbon content and composition of soil minerals. The sorption and desorption isotherms of PFOA on ten soils were linear, except for the sorption of PFOA onto a few soils, which was described by the Freundlich equation with the parameter N >1. The main sorption mechanism of PFOA was hydrophobic interaction between the perfluorinated carbon chain and the organic matter of soil, as evidenced by the correlation between the solid-liquid distribution coefficient and the fraction of soil organic carbon. The sorption of PFOA in soils was highly irreversible. [ABSTRACT FROM AUTHOR]

Many epidemiology studies have investigated associations of perfluorooctanoate (PFOA) exposures with a variety of adverse health outcomes for participants in the C8 Health Project. The exposure concentrations (i.e., air and groundwater) used in these studies were determined primarily based on participant’s residential locations. However, for residential addresses that could not be geocoded to the street level, the exposure concentrations were assigned based on population-weighted ZIP code centroid, which may result in exposure mischaracterization. The aim of this current study is to evaluate the potential impact of mischaracterized exposure concentrations due to geocoding uncertainty on the predicted serum PFOA concentrations and the epidemiological association between PFOA exposure and preeclampsia. For both workplace addresses and incompletely geocoded residential addresses, we used Monte Carlo (MC) simulation to assign alternate geographic locations within the reported ZIP code (instead of population-weighted ZIP code centroids) and the corresponding exposure concentrations. We found that mischaracterization of residential exposure due to population-weighted ZIP code centroid assignment had no significant impact on the serum PFOA concentration predictions and the epidemiological association of PFOA exposure with preeclampsia. In contrast, the uncertainty in workplace exposure moderately impacted the rank exposure among the participants. We observed a 41% increase in the average adjusted odds ratio of preeclampsia occurrence that may be due to differing proportions of cases (64.3%) and controls (54.5%) with workplace address geocodes during pregnancy. This finding suggests that differential exposure mischaracterization can be reduced by obtaining accurate exposure information such as street addresses and tap water consumption, for both workplaces and residences. The analysis we present is one approach for estimating the potential impacts of positional errors in a geocoding-based exposure assessment on exposure estimates and epidemiological study results. [ABSTRACT FROM AUTHOR]

We recently utilized a suite of environmental fate and transport models and an integrated exposure and pharmacokinetic model to estimate individual perfluorooctanoate (PFOA) serum concentrations, and also assessed the association of those concentrations with preeclampsia for participants in the C8 Health Project (a cross-sectional study of over 69,000 people who were environmentally exposed to PFOA near a major U.S. fluoropolymer production facility located in West Virginia). However, the exposure estimates from this integrated model relied on default values for key independent exposure parameters including water ingestion rates, the serum PFOA half-life, and the volume of distribution for PFOA. The aim of the present study is to assess the impact of inter-individual variability and epistemic uncertainty in these parameters on the exposure estimates and subsequently, the epidemiological association between PFOA exposure and preeclampsia. We used Monte Carlo simulation to propagate inter-individual variability/epistemic uncertainty in the exposure assessment and reanalyzed the epidemiological association. Inter-individual variability in these parameters mildly impacted the serum PFOA concentration predictions (the lowest mean rank correlation between the estimated serum concentrations in our study and the original predicted serum concentrations was 0.95) and there was a negligible impact on the epidemiological association with preeclampsia (no change in the mean adjusted odds ratio (AOR) and the contribution of exposure uncertainty to the total uncertainty including sampling variability was 7%). However, when epistemic uncertainty was added along with the inter-individual variability, serum PFOA concentration predictions and their association with preeclampsia were moderately impacted (the mean AOR of preeclampsia occurrence was reduced from 1.12 to 1.09, and the contribution of exposure uncertainty to the total uncertainty was increased up to 33%). In conclusion, our study shows that the change of the rank exposure among the study participants due to variability and epistemic uncertainty in the independent exposure parameters was large enough to cause a 25% bias towards the null. This suggests that the true AOR of the association between PFOA and preeclampsia in this population might be higher than the originally reported AOR and has more uncertainty than indicated by the originally reported confidence interval. [ABSTRACT FROM AUTHOR]

Background Previous studies on the exposure to perfluoroalkyl acids (PFAAs) and female fertility have provided conflicting results. We aimed to investigate the association between several PFAAs and time to pregnancy among nulliparous women. Methods From 2008 to 2013, we included 1372 women from the Aarhus Birth Cohort, Aarhus University Hospital, Denmark, who provided data on time to pregnancy and a blood sample before 20 gestational weeks. We measured the levels of 16 PFAAs in maternal serum and report data for seven compounds with quantifiable values in at least 50% of samples. Fecundability ratios according to PFAA levels (quartiles or continuous levels) were estimated by discrete-time survival analyses, adjusted for potential confounders. We further investigated the association between PFAAs and infertility (time to pregnancy>12 months or infertility treatment prior to the studied pregnancy) by multivariable logistic regression. Results Median levels of perfluorooctane sulfonate and perfluorooctanoate were 8.3 and 2.0 ng/mL. Overall, no obvious associations were found between any PFAAs and fecundability or infertility. Adjusted fecundability ratios (95% confidence intervals) were 1.09 (0.92–1.29) for perfluorooctane sulfonate and 1.10 (0.93–1.30) for perfluorooctanoate (highest versus lowest quartile). Conclusions We found no evidence of an association between present serum levels of PFAAs and longer time to pregnancy or infertility in nulliparous women. This study further adds to the sparse knowledge on PFAAs besides perfluorooctane sulfonate and perfluorooctanoate. [ABSTRACT FROM AUTHOR]

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are ubiquitous in the environment and accumulate in humans. PFAS are suspected to affect the neuropsychological function of children, but only few studies have evaluated the association with childhood attention and executive function. To investigate the association between intrauterine exposure to PFAS and offspring attention and executive function. A total of 1593 children from the Danish National Birth Cohort, born 1996–2003, were included. The levels of 16 PFAS were measured in maternal plasma during pregnancy. At 5 years of age, the Test of Everyday Attention for Children at Five (TEACh-5) and the Behavior Rating Inventory of Executive Function (BRIEF) were performed. TEACh-5 scores were standardized to a mean of 0 and standard deviation (SD) of 1. BRIEF scores were standardized to a mean of 50 and a SD of 10. The associations between levels of seven PFAS and TEACh-5 and BRIEF were examined by multivariable linear regression adjusted for potential confounders. Perfluorooctane sulfonamide (PFOSA) was associated with poorer selective attention [standardized mean difference (95% confidence interval) −0.5 (−0.7, −0.3), highest versus lowest quartile]. Other PFAS were not clearly associated with selective attention, and we found no clear associations between PFAS exposure and sustained attention. For parent rated executive function, perfluorooctanoate (PFOA) was associated with poorer scores, standardized mean difference 3.8 (95% confidence interval 1.6, 6.0), highest versus lowest quartile. Regarding other PFAS, the associations were less clear. We found no clear associations between any PFAS and executive function rated by preschool teachers. Intrauterine exposure to PFOSA was associated with poorer selective attention, while PFOA was associated with poorer executive function. Given the widespread nature of PFAS exposure, these findings may have public health implications, warranting further investigation. • Plasma samples were obtained during pregnancy in 1593 Danish women. • Perfluoroalkyl and polyfluoroalkyl substances (PFAS) were measured in the plasma. • Attention and executive function was evaluated in the offspring at age 5. • Perfluorooctane sulfonamide (PFOSA) was associated with poorer selective attention. • Perfluorooctanoate (PFOA) was associated with poorer executive function. [ABSTRACT FROM AUTHOR]

Abstract: We examined whether perfluorooctanoate (PFOA) or perfluorooctane sulfonate (PFOS) had obesogenic effects and if they increased spontaneous intestinal tumorigenesis in the mouse model C57BL/6J-Min/+ (multiple intestinal neoplasia) after in utero exposure. The dams were exposed to PFOA or PFOS (0.01, 0.1 or 3.0mg/kg bw/day) by po gavage on GD1–17. The Min/+ and wild-type offspring were terminated at week 11 for examination of intestinal tumorigenesis or at week 20 for obesogenic effect, respectively. Body weights of the dams and pups were recorded throughout life. Food intake was determined at week 6 and 10. Blood glucose (non-fasted) was measured at week 6 and 11. No obesogenic effect of PFOA or PFOS was observed up to 20 weeks of age. PFOA or PFOS did not increase the incidence or number of tumors in the small intestine or colon of the Min/+ mice or affect their location along the intestines. Feed intake was not affected. There were some indications of toxicity of PFOA, but not of PFOS. There was lower survival of pups after 3.0mg/kg PFOA, lower body weight in pups after 3.0 and possibly 0.1mg/kg PFOA, and increased relative liver weight after 0.01 and possibly 0.1mg/kg PFOA. Plasma glucose was lower after 0.01 and 0.1mg/kg PFOA. In conclusion, exposure to PFOA and PFOS in utero with the doses used did not have obesogenic effect on either Min/+ or wild-type mice, at least not up to 11 or 20 weeks of age, nor increased intestinal tumorigenesis in Min/+ mice. [Copyright &y& Elsevier]

Background: Recent studies have shown effects of prenatal exposure to perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) on infants in the general environmental levels. Laboratory animal studies have shown that exposure to PFOS and PFOA is associated with immunotoxic effects. Objectives: To investigate the relationship between maternal PFOS and PFOA levels and infant allergies and infectious diseases during the first 18 months of life. Cord blood immunoglobulin (Ig) E levels were also evaluated. Methods: We conducted a prospective cohort study of pregnant women from 2002 to 2005 in Sapporo, Japan. Maternal PFOS and PFOA levels were measured in relation to cord blood IgE concentrations (n=231) and infant allergies and infectious diseases (n=343). Characteristics of mothers and their infants were obtained from self-administered questionnaires and medical records. Development of infant allergies and infectious diseases was determined from self-administered questionnaires at 18 months of age. Concentrations of PFOS and PFOA in maternal serum and concentrations of IgE in umbilical cord serum at birth were measured. Results: Cord blood IgE levels decreased significantly with high maternal PFOA concentration among female infants. However, there were no significant associations among maternal PFOS and PFOA levels and food allergy, eczema, wheezing, or otitis media in the 18 month-old infants (adjusted for confounders). Conclusions: Although cord blood IgE level decreased significantly with high maternal PFOA levels among female infants, no relationship was found between maternal PFOS and PFOA levels and infant allergies and infectious diseases at age in 18 months. [Copyright &y& Elsevier]

Abstract: Objectives: To examine whether prenatal exposure to perfluorooctanesulfonate (PFOS) or perfluorooctanoate (PFOA) is associated with the occurrence of hospitalization for infectious diseases during early childhood. Methods: We randomly selected 1400 pregnant women and their offspring from the Danish National Birth Cohort (1996–2002) and measured PFOS and PFOA levels in maternal blood during early pregnancy. Hospitalizations for infection of the offspring were identified by the linkage to the National Hospital Discharge Register through 2008. Results: Hospitalizations due to infections were not associated with prenatal exposure to PFOA and PFOS. On the contrary, the relative risks of hospitalizations ranged from 0.71 to 0.84 for the three higher quartiles of maternal PFOA levels compared with the lowest, but no dose-response pattern was found. No clear pattern was observed when results were stratified by child’s age at infection, with the exception of an inverse association between maternal PFC levels and risk of hospitalization during the child’s first year of life. Conclusions: These findings suggest that prenatal exposure to PFOA or PFOS is not associated with increased risk of infectious diseases leading to hospitalization in early childhood. [ABSTRACT FROM AUTHOR]

Abstract: Recent concerns have been raised concerning the widespread distribution of perfluorinated compounds in environmental matrices and biota. The compounds of interest include ammonium perfluorooctanoate (APFO, the ammonium salt of perfluorooctanoic acid, PFOA). APFO is used primarily as a processing aid in the production of fluoropolymers and fluoroelastomers. The environmental presence of perfluorooctanoate (PFO−, the anion of APFO) and its entry into the environment as APFO make quality aquatic toxicity data necessary to assess the aquatic hazard and risk of APFO. We conducted acute and chronic freshwater aquatic toxicity studies with algae, Pseudokirchneriella subcapitata, the water flea, Daphnia magna, and embryo-larval rainbow trout, Oncorhynchus mykiss, using OECD test guidelines and a single, well-characterized sample of APFO. Acute 48–96h LC/EC50 values were greater than 400mg/l APFO and the lowest chronic NOEC was 12.5mg/l for inhibition of the growth rate and biomass of the freshwater alga. Un-ionized ammonia was calculated to be a potential significant contributor to the observed toxicity of APFO. Based on environmental concentrations of PFO− from various aquatic ecosystems, the PNEC value from this study, and unionized ammonia contributions to observed toxicity, APFO demonstrates little or no risk for acute or chronic toxicity to freshwater and marine aquatic organisms at relevant environmental concentrations. [Copyright &y& Elsevier]

Interest in human exposure to perfluorinated acids, including perfluorobutanesulfonate (PFBS), perfluorohexanesulfonate (PFHS), perfluorooctanesulfonate (PFOS), and perfluorooctanoate (PFOA) has led to their measurement in whole blood, plasma and serum. Comparison of measurements in these different blood-based matrices, however, has not been rigorously investigated to allow for across-matrix comparisons. This research evaluated concentrations of PFBS, PFHS, PFOS, and PFOA in whole blood collected in heparin (lithium) and ethylenediamine tetraacetic acid (EDTA), plasma samples collected in heparin and EDTA, and serum (from whole blood allowed to clot). Blood samples were collected from 18 voluntary participants employed at 3M Company. Solid phase extraction methods were used for all analytical sample preparations, and analyses were completed using high-pressure liquid chromatography/tandem mass spectrometry methods. Serum concentrations ranged from: limit of quantitation (LOQ, 5ng/mL) to 25ng/mL for PFBS; LOQ (5ng/mL) to 75ng/mL for PFHS; LOQ (5ng/mL) to 880ng/mL for PFOS; and LOQ (5 or 10ng/mL) to 7320ng/mL for PFOA. Values less than the LOQ were not included in the statistical analyses of the mean of the ratios of individual values for the matrices. PFBS was not quantifiable in most samples. Serum to plasma ratios for PFHS, PFOS, and PFOA were 1:1 and this ratio was independent of the level of concentrations measured. Serum or plasma to whole blood ratios, regardless of the anticoagulant used, approximated 2:1. The difference between plasma and serum and whole blood corresponded to volume displacement by red blood cells, suggesting that the fluorochemicals are not found intracellularly or attached to the red blood cells. [Copyright &y& Elsevier]

Abstract: Turtles rank high in the river food chain, and are suitable for predicting the bioconcentrations of chemicals through the food chain. Trachemys scripta elegans () and Chinemys reevesii () were captured in a river in Japan, from September to October 2003 and April to June 2004. Surface water samples were collected simultaneously from the same sites at which the turtles were caught. Serum perfluorooctane sulfonate (PFOS) ranged from 2.4 to 486μg/L, while water PFOS levels ranged from 2.9 to 37ng/L. The geometric mean (GM) (geometric standard deviation, GSD) of the bioconcentration factor (BCF) of PFOS was 10,964 (2.5). In contrast, the perfluorooctanoate (PFOA) level in water ranged from 16.7–87,100ng/L, and serum PFOA ranged from <0.2 to 870μg/L. The GM (GSD) of the BCF of PFOA was 3.2 (7.9). Furthermore, the BCF of PFOA decreased as the PFOA level in the surface water increased. PFOS could be preferentially bioconcentrated in biota, and PFOA, slightly bioconcentrated. [Copyright &y& Elsevier]

Abstract: PFOS and PFOA are ubiquitous contaminants in the environment. We investigated the effects of fluorochemicals on calcium currents in Paramecium caudatum using its behavioral changes. Negatively charged amphiphiles prolonged backward swimming (BWS) of Paramecium. PFOS significantly prolonged BWS, while PFOA was less potent (EC50: 29.8±4.1 and 424.1±124.0μM, respectively). The BWS prolongation was blocked by cadmium, indicating that the cellular calcium conductance had been modified. The positively charged amphiphile FOSAPrTMA shortened BWS (EC50: 19.1±17.3). Nonionic amphiphiles did not affect BWS. The longer-chain perfluorinated carboxylates PFNA and PFDA were more potent than PFOA (EC50: 98.7±20.1 and 60.4±10.1μM, respectively). However, 1,8-perfluorooctanedioic acid and 1,10-perfluorodecanedioic acid did not prolong BWS. The critical micelle concentration (CMC) and BWS prolongation for negatively charged amphiphiles showed a clear correlation (r 2 =0.8008, p <0.001). In summary, several perfluorochemicals and PFOS and PFOA had similar effects in Paramecium, while chain length, CMC, and electric charge were major determinants of BWS duration. [Copyright &y& Elsevier]

Abstract: Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are detected in the environment, as well as more specifically in wildlife and humans. However, the toxicokinetic aspects of perfluorochemicals in humans are unclear. In this study, we measured concentrations of PFOA and PFOS in subjects who had lived in Kyoto city for more than 10 years. The serum concentrations of PFOA and PFOS were higher in females who menstruated than those who did not menstruation (), but in males this did not change by age; the levels in females reached those in males at an age of ⩾60 years. We then determined the renal clearances of PFOA and PFOS in young (20–40 years old, for each sex) and old (⩾60 years old, for each sex) subjects of both sexes. All young females were menstruating, while all old females were not. The renal clearances were 10−5-fold smaller than the glomerular filtration rate in humans, suggesting the absence of active excretion in human kidneys. The renal clearances of PFOA and PFOS were approximately one-fifth of the total clearance based on their serum half-lives, assuming a one-compartment model. The sex differences in renal clearance that have been reported in rats and Japanese macaques were not found in our human subjects. We tried to build a one-compartment pharmacokinetic model using the reported half-lives in human. The model was simple but could predict the serum concentrations in both males and females fairly well. We therefore suggest that an internal dose approach using a pharmacokinetic model should be taken because of the large species differences in kinetics that exist for PFOA and PFOS. [Copyright &y& Elsevier]

Abstract: Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are amphiphiles found ubiquitously in the environment, including wildlife and humans, and are known to have toxic effects on physiological functions of various tissues. We investigated the effects of PFOS and PFOA on action potentials and L-type Ca2+ currents, ICaL, in isolated guinea-pig ventricular myocytes using whole-cell patch-clamp recording. In current-clamp experiments, PFOS significantly decreased the rate of spike, action potential duration, and peak potential at doses over 10μM. In voltage-clamp experiments, PFOS increased the voltage-activated peak amplitude of ICaL, and shifted the half-activation and inactivation voltages of ICaL to hyperpolarization. PFOA had similar effects PFOS, but showed significantly lower potency. These findings are consistent with previous observations for anionic n-alkyl surfactants, suggesting that PFOS and PFOA may change membrane surface potential, thereby eliciting general effects on calcium channels. These findings provide further insights into the mechanisms of PFOA and PFOS toxicities. [Copyright &y& Elsevier]

Perfluorooctanoate (PFOA), an environmentally and metabolically stable perfluorinated carboxylic acid, has been detected in the serum of children, adults and the elderly from the United States with the upper bound of the 95th percentile estimate in the range of 0.011–0.014 μg/mL (ppm). In this risk characterization, margins of exposure (MOE), which can provide a realistic perspective on potential for human risk, were determined by comparison of general population serum PFOA concentrations with serum concentrations from toxicological studies that are associated with the lower 95% confidence limit of a modeled 10 percent response or incidence level (LBMIC10) using USEPA BMDS software. The LBMIC10 was estimated using surrogate data from other studies or pharmacokinetic relationships if serum PFOA data were not available. Modeled dose–responses (with resulting LBMIC10 values) included post-natal effects in rats (29 μg/mL), liver-weight increase (23 μg/mL), and body-weight change (60 μg/mL) in rats and monkeys, and incidence of Leydig cell adenoma (125 μg/mL) in rats. MOE values based on the upper bound 95th percentile population serum PFOA concentration were large, ranging from 1600 (liver-weight increase) to 8900 (Leydig cell adenoma). These MOE values represent substantial protection of children, adults, and the elderly. [Copyright &y& Elsevier]

Perfluorooctanoate (PFOA) has been used extensively in the manufacture of both commercial and household products. PFOA serum concentrations have been associated with adverse health effects, including lower body mass in children and infants. To determine if there is an association between serum PFOA concentration and body mass, serum insulin and lipid profile in exposed young girls. We conducted a cross-sectional study of PFAS environmental biomarkers and insulin resistance in 6 to 8 year-old girls from Greater Cincinnati (n=353). In 2004–2006, blood samples were obtained to measure polyfluoroalkyl substances (PFAS), fasting insulin, glucose and lipids. Clinical exams included anthropometric measurements and pubertal maturation staging. Linear regression and mediation analyses, specifically structural equation modeling (SEM), were used to determine the strength and direction of the relationships between PFAS, pubertal maturation status, body mass index (BMI), cholesterol and insulin resistance. The median PFOA (7.7ng/ml) was twice the National Health and Nutrition Examination Survey (2005–2006). Only PFOA, a PFAS sub-species, showed statistically significant relationships with the outcomes. In regression models, PFOA was associated with decreased BMI and waist-to-height ratio (p=0.0008; p=0.0343), HDL-cholesterol (p=0.0046) and had a borderline inverse association with the HOMA Index of insulin resistance (p=0.0864). In SEM, PFOA retained an inverse relationship with BMI (p<0.0001) but the relationships with HOMA and HDL-cholesterol were no longer statistically significant. Pubertal initiation (Tanner breast or pubic stage 2 or greater) and BMI were associated with increased HOMA Index (p<0.0001). These findings suggest PFOA exposure in young girls affects both BMI and ultimately insulin resistance. In mediation analysis with puberty in the model, the direct effects of PFOA on insulin resistance and were reduced. • PFAS chemicals are commonly used in manufacturing and are widely detected in humans due to a half-life of 3-4 years. • Studies have shown PFAS exposure during developmental windows results in decreased weight and changes in the lipid profile. • Median serum levels of PFOA in a population of girls, exposed through drinking water, were almost twice the NHANES level. • A strong linear relationship was found between PFOA and BMI, PFOA and HDL cholesterol. • Structural equation modeling revealed that the PFOA exposure effect of decreasing BMI consequently decreased insulin resistance. [ABSTRACT FROM AUTHOR]