Web Date: April 14, 2011
People's Exposure To Perfluorochemicals Fluctuated Over Time
Perfluorochemicals can protect fabrics from stains and food wrappers from grease, but the chemicals worry environmental and public health scientists. In 2000, scientists detected these persistent pollutants in the blood of humans and wildlife worldwide. Now researchers report that from 1999 to 2008, concentrations of these compounds in human blood fluctuated. The ups and downs, they found, link to voluntary and government-mandated changes in manufacturing (Environ. Sci. Technol., DOI: 10.1021/es1043613).
Antonia M. Calafat and her colleagues at the Centers for Disease Control and Prevention measured levels of the common perfluorochemicals perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), and perfluorononanoate (PFNA) in blood samples collected as part of the agency's National Health and Nutrition Examination Survey. Every year, the survey collects health and demographic data on 5,000 people who are representative of the U.S. population as a whole.
Since 2000, the researchers found, PFOS concentrations fell significantly, dropping by about 64% in women and 49% in men. From 1999 to 2008, however, PFNA concentrations in both men and women more than doubled. Meanwhile, PFOA concentrations remained unchanged from 2003 to 2008.
These trends appear to reflect changes in manufacturing prompted in part by regulatory action, the authors write. In 2002, 3M, the major manufacturer of PFOS and PFOA, stopped making the chemicals, but DuPont and other manufacturers soon started producing PFOA. Even though these new producers had modified the manufacturing processes in response to government action, products of the process likely continue to contribute to people's PFOA exposure, the authors conclude, and may also account for the upward trend in PFNA.
Toxicologist Kannan Kurunthachalam of the State University of New York, Albany, praises the study because it illustrates how government action has affected people's exposure to perfluorochemicals.
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