Trends in Exposure to Polyfluoroalkyl Chemicals in the U.S. Population: 1999−2008

• Published in: Environmental science & technology 2011-10, Vol.45 (19), p.8037-8045
• Main Authors: Kato, Kayoko, Wong, Lee-Yang, Jia, Lily T, Kuklenyik, Zsuzsanna, Calafat, Antonia M
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Age Distribution; Aged; Biological and medical sciences; Caprylates - blood; Chemical and industrial products toxicology. Toxic occupational diseases; Chemicals; Child; Environmental Exposure - statistics & numerical data; Ethnicity; Female; Fluorocarbons - blood; Health Surveys - statistics & numerical data; Human exposure; Humans; Male; Medical sciences; Middle Aged; Models, Biological; Nutrition; Nutrition Surveys; Race; Sulfonic Acids - blood; Time Factors; Toxicology; Trends; United States; Various organic compounds; Young Adult
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es1043613

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.