Following are links to the abstracts of key published studies on PFOA and the safety of fluoropolymer products.
Fluoropolymer Products
Washburn, et al. “Exposure Assessment and Risk Characterization for Perfluorooctanoate in Selected Consumer Articles.” Environ. Sci. Technol. 39: 3904-3910.
This key study examines potential exposure to PFOA from a wide range of consumer products. The study found PFOA in the products to be nondetectable with the best available analytical methods, or so minute that potential exposures would be insignificant. Total potential human exposures from the consumer products studied are below the limits that can be measured using current technology. The study concludes that exposure from consumer products “would not have the potential to cause adverse health effects in infants, children, adolescents, adult residents or professional, even in sensitive individuals within the general population.”
Begley, et al. “Perfluorochemicals: Potential Sources of and Migration from Food Packaging.” Food Add. and Contam. 22 (10): 1023-1021.
This study, conducted by researchers at the Food and Drug Administration, examined nonstick cookware for residual levels of PFOA. The levels were found to be so low they could only be detected by grinding the nonstick coating into a powder and extracting it with solvent – a situation far removed from real world conditions and actual consumer use of nonstick products.
To determine if PFOA was formed during heating in nonstick cookware, three pans (frying or omelet style) were heated empty over a flame burner to 320 degrees Centigrade (320 ºC), equivalent to 606 degrees Fahrenheit (606 ºF). No detectable increase in PFOA was measured. FDA noted that food oils begin to generate smoke around 190 ºC (375 °F), which would be an indication that the cooking pan is overheating.
The authors conclude:
“The coated cookware tested here do not appear to be a significant source of PFOA which will migrate due to cookware’s low milligram per kilogram (mgkg-1) initial residual level of PFOA. Furthermore, an extreme heating test (abusive) of the cookware did not appear to increase the residual amount of PFOA in the cookware. That is, additional PFOA does not appear to form during the normal use or misuse of these products.”
Powley et al. “Determination of Perfluorooctanoic Acid (PFOA) Extractable from the Surface of Commercial Cookware Under Simulated Cooking Conditions by LC/MS/MS.” The Analyst 130: 1299-1302.
This peer-reviewed study published in The Analyst, a publication of the Royal Society of Chemistry (UK), shows no release of PFOA from nonstick coatings under conditions that mimic food contact use. For this study, a method was developed to determine if PFOA might be present in and extracted from the surface of commercial frying pans coated with a DuPont fluoropolymer under simulated cooking conditions. Commercial grade cookware was obtained, then extracted with water and ethanol/water mixtures at 100 and 125 ºC, and the resulting extracts were analyzed by liquid chromatography tandem mass spectrometry (LC/MS/MS). Detection and quantification limits as low as 100 picograms per centimeter squared of surface area (100 pg cm-2) were demonstrated. None of the fluoropolymer treated cookware samples analyzed showed detectable levels of PFOA when extracted under simulated cooking conditions.
PFOA
Butenhoff, et al. “Characterization of Risk to general population exposure to perfluorooctanoate.” Reg. Pharm. Toxic. 39 (3): 363-380.
This study reports the lowest no-effect levels (the maximum dose which produces no observed adverse effects) in laboratory animal studies, converts the dose to PFOA levels in blood and concludes that the blood levels are 1,800 to 8,900 times lower than the no-effect levels. The article concludes that there is an adequate margin of protection between human exposure levels, which are very low, and levels that cause harm in animal studies, which are much higher.
Paustenbach, et al. “A Methodology For Estimating Human Exposure to Perfluorooctanoic Acid (PFOA): A Retrospective Exposure Assessment of a Community (1951-2003).” J Tox & Env Health 70: 28-57, 2007.
This study assesses human exposure to PFOA in the immediate vicinity of a fluoropolymer manufacturing plant near Parkersburg, West Virginia. The study considered all possible emissions from the plant from the first use of PFOA (1951) through 2003, when fluoropolymer production was increased but PFOA emissions were significantly reduced by the installation of additional emission controls. Possible human exposure to all plant emissions were then predicted by modeling and compared to measured environmental concentrations in the vicinity of the plant. This comparison confirmed that the modeled data accurately estimated human exposure to PFOA for those living near the plant.
The estimated human exposure from PFOA emissions was found to be low when compared to the benchmark dose from laboratory animal studies. The “benchmark” dose is an estimate of the maximal safe dose in laboratory animals, determined as the highest dose at which no significant effects could be measured. The ratio of human exposure to the benchmark dose is called the margin of exposure, and ratios of 100-1000 are considered to be protective of human health. Margins of exposure in this study ranged from 9,000 to 13,000. This large margin of exposure indicates, as stated in the paper, that “the likelihood of adverse health effects due to exposure to PFOA is extremely low.”
The Paustenbach et al. study determined margins of human exposure to the same benchmark dose in laboratory animal studies (liver weight increase) as did the Butenhoff et al. study, discussed above. The Butenhoff et al. study compared estimated blood levels corresponding to the benchmark dose to measured general population exposures (blood levels) while Paustenbach et al. directly compared the benchmark dose to estimated human exposures based on measured plant emissions. The fact that both studies found high margins of exposure provides further assurance that the risk to human health from exposure to PFOA is low and the margins of exposure are protective of human health for the general population, including individuals living in the vicinity of a fluoropolymer plant.
Decreasing Levels of PFOA
Calafat, et al. "Polyfluoroalkyl Chemicals in the U.S. Population: Data from the National Health and Nutrition Examination Survey (NHANES) 2003-2004 and Comparisons with NHANES 1999-2000." Environmental Health Perspectives 115 (11): 1596-1602, 2007.
Centers for Disease Control and Prevention (CDC) scientists measured levels of 12 perfluorinated chemicals in 2,094 samples of blood collected from individuals as part of the 2003-2004 National Health and Nutrition Examination Survey (NHANES) and compared the data to levels of the same perfluorinated chemicals measured in 1999-2000. The study detected PFOA and three other perfluorinated chemicals in more than 98 percent of the samples, but the geometric mean concentrations were significantly lower (approximately 25% for PFOA) than the concentrations reported in NHANES 1999-2000. The authors conclude that the apparent reductions in concentrations of PFOA most likely are related to the discontinuation in 2002 of industrial production of PFOA by electrochemical fluorination.