Tag Archives: perfluoroctanoic acid (PFOA)

Perfluorooctanoic acid (PFOA) literature review…

Post, G.B., Cohn, P.D., Cooper, K.R. Perfluorooctanoic acid (PFOA), an emerging drinking water contaminant: A critical review of recent literature. Environmental Research, Volume 116, July 2012, Pages 93–117.

Perfluorooctanoic acid (PFOA) is an anthropogenic contaminant that differs in several ways from most other well-studied organic chemicals found in drinking water. PFOA is extremely resistant to environmental degradation processes and thus persists indefinitely. Unlike most other persistent and bioaccumulative organic pollutants, PFOA is water-soluble, does not bind well to soil or sediments, and bioaccumulates in serum rather than in fat. It has been detected in finished drinking water and drinking water sources impacted by releases from industrial facilities and waste water treatment plants, as well as in waters with no known point sources. However, the overall occurrence and population exposure from drinking water is not known. PFOA persists in humans with a half-life of several years and is found in the serum of almost all U.S. residents and in populations worldwide. Exposure sources include food, food packaging, consumer products, house dust, and drinking water. Continued exposure to even relatively low concentrations in drinking water can substantially increase total human exposure, with a serum:drinking water ratio of about 100:1. For example, ongoing exposures to drinking water concentrations of 10 ng/L, 40 ng/L, 100 ng/L, or 400 ng/L are expected to increase mean serum levels by about 25%, 100%, 250%, and 1000%, respectively, from the general population background serum level of about 4 ng/mL. Infants are potentially a sensitive subpopulation for PFOA’s developmental effects, and their exposure through breast milk from mothers who use contaminated drinking water and/or from formula prepared with contaminated drinking water is higher than in adults exposed to the same drinking water concentration. Numerous health endpoints are associated with human PFOA exposure in the general population, communities with contaminated drinking water, and workers. As is the case for most such epidemiology studies, causality for these effects is not proven. Unlike most other well-studied drinking water contaminants, the human dose-response curve for several effects appears to be steepest at the lower exposure levels, including the general population range, with no apparent threshold for some endpoints. There is concordance in animals and humans for some effects, while humans and animals appear to react differently for other effects such as lipid metabolism. PFOA was classified as “likely to be carcinogenic in humans” by the USEPA Science Advisory Board. In animal studies, developmental effects have been identified as more sensitive endpoints for toxicity than carcinogenicity or the long-established hepatic effects. Notably, exposure to an environmentally relevant drinking water concentration caused adverse effects on mammary gland development in mice. This paper reviews current information relevant to the assessment of PFOA as an emerging drinking water contaminant. This information suggests that continued human exposure to even relatively low concentrations of PFOA in drinking water results in elevated body burdens that may increase the risk of health effects.

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Perfluorooctanoic acid (PFOA) exposure found not associated with adverse pregnancy outcomes

No associations were found between estimated serum PFOA levels and adverse pregnancy outcomes other than possibly preeclampsia….

Savitz, DA, Stein, CR, Bartell, SM, Elston, B, Gong, J. Shin, HM, Wellenius, GA. Perfluorooctanoic Acid Exposure and Pregnancy Outcome in a Highly Exposed Community. Epidemiology. 2012 Feb 24.

BACKGROUND: We assessed the association between perfluorooctanoic acid (PFOA) and pregnancy outcome in an area with elevated exposure to PFOA from drinking water contaminated by chemical plant releases.

METHODS: Serum PFOA was measured, and reproductive and residential histories were obtained during 2005-2006. We estimated serum PFOA levels at the time of pregnancy for 11,737 pregnancies occurring between 1990 and 2006, based on historical information on PFOA releases, environmental distribution, pharmacokinetic modeling, and residential histories. We assessed the association between PFOA and the odds of miscarriage, stillbirth, preeclampsia, preterm birth, term low birthweight, and birth defects, controlling for calendar time, age, parity, education, and smoking. PFOA exposure was evaluated as a continuous measure (with and without log transformation) and in quintiles, combining the lowest 2 quintiles (<6.8 ng/mL) as the referent.

RESULTS: Measures of association between PFOA and miscarriage, preterm birth, term low birthweight, and birth defects were close to the null. Odds of stillbirth were elevated in the fourth quintile only. For preeclampsia, the odds ratio was 1.13 (95 confidence interval =1.00-1.28) for an interquartile shift in log-transformed PFOA, and the odds ratios were 1.1-1.2 across the upper 3 quintiles of exposure.

CONCLUSIONS: In this large, population-based study in a region with markedly elevated PFOA exposure, we found no associations between estimated serum PFOA levels and adverse pregnancy outcomes other than possibly preeclampsia. Conclusions are tempered by inherent limitations in exposure reconstruction and self-reported pregnancy outcome information.

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Mondal et al 2012: Relationships of Perfluorooctanoate and Perfluorooctane Sulfonate Serum Concentrations Between Child-Mother Pairs in a Population with Perfluorooctanoate Exposure from Drinking Water

Mondal, D., Lopez-Espinosa, M.J., Armstrong, B., Stein, C.R., and Fletcher, T. Relationships of Perfluorooctanoate and Perfluorooctane Sulfonate Serum Concentrations Between Child-Mother Pairs in a Population with Perfluorooctanoate Exposure from Drinking Water. Environ Health Perspect. 2012 Jan 23.

Background: There are limited data on the associations between maternal, newborn and child exposure to perfluoroalkyl acids (PFAAs), including perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS). This study provides an opportunity to assess the association between PFAA concentrations in mother-child pairs in a population exposed to PFOA via drinking water.

Objectives: To determine the relationship between child-mother PFAA serum concentrations, and examine how the child:mother ratio varies with child’s age, child’s gender, drinking water PFOA concentration, reported bottle water usage and mother’s breastfeeding intention.

Methods: We studied 4,943 child-mother pairs (child age: 1-19 years). The child:mother PFAA ratio was stratified by possible determinants. Results are summarized as geometric mean ratios and correlation coefficients between child-mother pairs, overall and within strata.

Results: Child and mother PFOA and PFOS concentrations were correlated (r=0.82 and 0.26, respectively). Children had higher serum PFOA concentrations than their mothers up to about age 12 years. The highest child:mother PFOA ratio was found among children ≤5 years (44% higher than their mothers) which we attribute to in utero exposure and to exposure via breast milk and drinking water. Higher PFOS concentrations in children persisted until at least 19 years of age (42% higher than their mothers). Boys aged >5 years had significantly higher PFOA and PFOS child:mother ratios than girls.

Conclusion: Concentrations of both PFOA and PFOS tended to be higher in children than their mothers. This difference persists until they are about 12 years for PFOA and at least until 19 years of age for PFOS.

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Loccisano et al 2011: Evaluation and prediction of pharmacokinetics of PFOA and PFOS in the monkey and human using a PBPK model

Loccisano, A.E., J.L. Campbell, Jr., M.E. Anderson, and H.J. Clewell, 3rd. Evaluation and prediction of pharmacokinetics of PFOA and PFOS in the monkey and human using a PBPK model. Regul Toxicol Pharmacol. 2011 Feb;59(1):157-75.

Perfluoroalkyl acid carboxylates and sulfonates (PFAAs) have many consumer and industrial applications. The persistence and widespread distribution of these compounds in humans have brought them under intense scrutiny. Limited pharmacokinetic data is available in humans; however, human data exists for two communities with drinking water contaminated by PFAAs. Also, there is toxicological and pharmacokinetic data for monkeys, which can be quite useful for cross-species extrapolation to humans. The goal of this research was to develop a physiologically-based pharmacokinetic (PBPK) model for PFOA and PFOS for monkeys and then scale this model to humans in order to describe available human drinking water data. The monkey model simulations were consistent with available PK data for monkeys. The monkey model was then extrapolated to the human and then used to successfully simulate the data collected from residents of two communities exposed to PFOA in drinking water. Human PFOS data is minimal; however, using the half-life estimated from occupational exposure, our model exhibits reasonable agreement with the available human serum PFOS data. It is envisioned that our PBPK model will be useful in supporting human health risk assessments for PFOA and PFOS by aiding in understanding of human pharmacokinetics.

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Liou et al 2010: Investigating the biodegradability of perfluorooctanoic acid

Bottom line of this study….Perfluorooctanoic acid (PFOA) is not biodegradable…

Liou, J.S., B. Szostek, C.M. DeRito, and E.L. Madsen. Investigating the biodegradability of perfluorooctanoic acid. Chemosphere. 2010 Jun;80(2):176-83. Epub 2010 Apr 3.

Perfluorooctanoic acid (PFOA) is an industrial chemical that has become disseminated globally in aquatic and terrestrial habitats, humans, and wildlife. Understanding PFOA’s biodegradability (susceptibility to microbial metabolic attack) is a crucial element in developing an informed strategy for predicting and managing this compound’s environmental fate. Reasoning that PFOA might be susceptible to reductive defluorination by anaerobic microbial communities, we embarked on a 2-phase experimental approach examining the potential of five different microbial communities (from a municipal waste-water treatment plant, industrial site sediment, an agricultural soil, and soils from two fire training areas) to alter PFOA’s molecular structure. A series of primarily anaerobic incubations (up to 259d in duration) were established with acetate, lactate, ethanol, and/or hydrogen gas as electron donors and PFOA (at concentrations of 100 ppm and 100 ppb) as the electron acceptor. Cometabolism of PFOA during reductive dechlorination of trichloroethene (TCE) and during reduction of nitrate, iron, sulfate, and methanogenesis were also examined. Endpoints of potential PFOA transformation included release of fluoride and detection of potential transformation products by LC/Orbitrap MS and LC/accurate radioisotope counting in a (14)C radiotracer study. The strongest indication of PFOA transformation occurred during its potential cometabolism at the 100 ppb concentration during reductive dechlorination of TCE. Despite an extensive search for transformation products to corroborate potential cometabolism of PFOA, we were unable to document any alteration of PFOA’s chemical structure. We conclude that, under conditions examined, PFOA is microbiologically inert, hence environmentally persistent.

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Cornelis et al 2011: First assessment of population exposure to perfluorinated compounds in Flanders, Belgium

C. Cornelis, W. D’Hollander, L. Roosen, A. Covaci, R. Smolders, R. Van Den Heuvel, E. Govarts, K. Van Campenhout, H. Reynders, and L. Bervoets. First assessment of population exposure to perfluorinated compounds in Flanders, Belgium. Chemosphere 2011 Nov. 18.

With the objective to evaluate exposure of the population in Flanders (Belgium) to perfluorinated compounds (PFCs), we measured perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in settled dust in homes and offices, in a selection of food items from local origin, in drinking-water and in human serum. We complemented the data with results from a literature survey. Based on this dataset we calculated intake by children and adults from food, drinking-water, settled dust and soil, and air. Dietary exposure dominated overall intake. For adults, average dietary intake equalled 24.2 (P95 40.9) ng PFOS kg(-1)d(-1) and 6.1 (P95 9.6) ng PFOA kg(-1)d(-1), whereas for children the dietary intake was about 3 times higher. Predicted intake is high when compared to assessments in other countries, and to serum levels from Flanders, but comparable to the intakes published by The European Food Safety Authority (EFSA) in 2008. Intake of PFOS and PFOA remained below the Tolerable Daily Intake.

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