Academic journal article Environmental Health Perspectives

Epidemiologic Evidence on the Health Effects of Perfluorooctanoic Acid (PFOA)

Academic journal article Environmental Health Perspectives

Epidemiologic Evidence on the Health Effects of Perfluorooctanoic Acid (PFOA)

Article excerpt

OBJECTIVE AND SOURCES: We reviewed the epidemiologic literature for PFOA.

DATA SYNTHESIS: Perfluorooctanoic acid (PFOA) does not occur naturally but is present in the serum of most residents of industrialized countries (U.S. median, 4 ng/mL). Drinking water is the primary route of exposure in some populations, but exposure sources are not well understood. PFOA has been used to manufacture such products as Gore-Tex and Teflon. PFOA does not break down in the environment; the human half-life is estimated at about 3 years. PFOA is not metabolized in the body; it is not lipophilic. PFOA is not directly genotoxic; animal data indicate that it can cause several types of tumors and neonatal death and may have toxic effects on the immune, liver, and endocrine systems. Data on the human health effects of PFOA are sparse. There is relatively consistent evidence of modest positive associations with cholesterol and uric acid, although the magnitude of the cholesterol effect is inconsistent across different exposure levels. There is some but much less consistent evidence of a modest positive correlation with liver enzymes. Most findings come from cross-sectional studies, limiting conclusions. Two occupational cohort studies do not provide consistent evidence for chronic disease; both are limited by sample size and reliance on mortality data. Reproductive data have increased recently but are inconsistent, and any observed adverse effects are modest.

CONCLUSIONS: Epidemiologic evidence remains limited, and to date data are insufficient to draw firm conclusions regarding the role of PFOA for any of the diseases of concern.

KEY WORDS: epidemiology, health effects, PFOA. Environ Health Perspect 118:1100-1108 (2010). doi:10.1289/ehp.0901827 [Online 27 April 2010]


Perfluorooctanoic acid (PFOA, or C8) is a perfluorinated compound (PFC) that does not occur naturally but was introduced in the environment after World War II. PFCs are fluoro-carbons with at least one additional atom or functional group; PFOA has a carboxylic acid group ([C.sub.7][F.sub.15]COOH). Most people tested in the United States have PFOA in their serum (measured via perfluorooctanoate, the disassociated ion of PFOA), with a median of 4 ng/mL, but the source of exposure is not clear (Calafat et al. 2007b). PFOA has also been detected in the serum of populations in a number of industrialized countries (Fromme et al. 2009; Kannan et al. 2004; Lau et al. 2007). Limited data suggest that PFOA in water systems may result from wastewater treatment plants, which concentrate PFOA (Becker et al. 2008; Pistocchio and Loos 2009). Levels of PFOA in the serum appear to be decreasing in the U.S. population, because some large users have curtailed emissions (Calafat et al. 2007b; Olsen et al. 2007b).

Determinants of PFOA in the general population are known to include age (higher at younger and older ages), sex (males higher), and race (whites higher) (Calafat et al. 2007a, 2007b; Emmett et al. 2006a; Steenland et al. 2009a). However, none of these attributes are very strong predictors. For those living near a point source of contamination, contamination of drinking water has been identified as the major route of exposure (Emmett et al. 2006a; Holzer et al. 2008; Steenland et al. 2009a).

PFOA has been used in the production of a wide variety of industrial and consumer products, such as Gore-Tex and Teflon. PFOA does not break down once in the environment, because of the strong carbon-fluorine bonds, leading to widespread buildup and bioaccumulation. Two studies provide estimates of the half-life for PFOA in humans. In a study of 26 retired fluorochemical production workers (mean years retired at initial blood collection, 2.6), followed up for 5 years, the median half-life was 3.4 years (Olsen et al. 2007a). In a study of 200 people who had been exposed via public water supplies and followed for 1 year after installation of filtration for the water supplies, the median half-life was 2. …

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