An analysis of nearly 300 umbilical cord blood samples led by researchers at the Johns Hopkins Bloomberg School of Public Health shows that newborn babies are exposed to perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) while in the womb. PFOS and PFOA are polyfluoroalkyl compounds (PFCs)--ubiquitous man-made chemicals used in a variety of consumer products, including as a protective coating on food-contact packaging, textiles and carpets, and in the manufacturing of insecticides. The health impact from exposure to these compounds is not fully known, but previous studies found these compounds could cause tumors and developmental toxicity in laboratory animals at doses much higher than those observed in the Hopkins study.
The analysis conducted in Baltimore, Md., detected PFOS in 99 percent of the infant samples examined and PFOA in 100 percent of those examined. The results are published in the April 20, 2007, online edition of the journal Environmental Science & Technology. Some of the study's findings were previously reported at the Society of Toxicology workshop held in February and at the International Conference on Environmental Epidemiology and Exposure held last September.
"When we began this research we weren't sure what we would find, because previously there was very little information about fetal exposure to PFOS and PFOA. Even though these chemicals are not bioaccumulative in fat, they are very persistent, which probably accounts for their presence in nearly every newborn," said Benjamin Apelberg, PhD, lead author of the study and a research associate in the Bloomberg School of Public Health's Department of Epidemiology. Apelberg conducted this work as part of his doctoral research.
The researchers analyzed cord serum from 299 newborns delivered at Johns Hopkins Hospital in Baltimore between 2004 and 2005. The samples were tested for the presence of PFOS and PFOA and eight other polyfluoroalkyl compounds. PFOA was detected in all of the samples and PFOS in all but two of the samples. The concentrations for both compounds were lower than those typically detected in adults in the United States and lower than those known to cause tumors and developmental problems in laboratory animals; more study is needed to understand health effects at these lower exposure levels.
PFOS concentrations were slightly higher in Black and Asian infants compared to White infants, but no correlation was found between concentrations and the mother's socioeconomic status, age, education, marital status or whether she lived within the city limits or not. In addition, the researchers found a strong correlation between concentrations of PFOS and PFOA even though the compounds come from different industrial sources. The finding suggests that humans may be exposed to both chemicals in a similar manner.
"This study confirms that, as we might have suspected, exposure to PFOS and PFOA is fairly universal; this is of particular concern because of the potential toxicity, especially developmental toxicity, for these chemicals and the lack of information about health risks at these exposure levels. What was surprising is how strongly they are associated with each other, given that they have very different uses. We will need additional research to understand how exposures are occurring in this region," said Lynn Goldman, MD, co-author of the study and a professor in the Department of Environmental Health Sciences at the Johns Hopkins Bloomberg School of Public Health.
Addition study authors include Antonia M. Calafat, Julie B. Herbstman, Zsuzsanna Kuklenyik, Jochen Heidler, Larry Needham, Rolf U. Halden and Frank Witter. Heidler and Halden are with the Johns Hopkins Bloomberg School of Public Health. Herbstman, formerly a doctoral student in epidemiology at the JHSPH is now at the Columbia Mailman School of Public Health and Witter is with the Johns Hopkins School of Medicine. Calafat, Kuklenyik and Needham are with the Centers for Disease Control and Prevention.
The research was supported by funding from the Johns Hopkins Bloomberg School of Public Health's Maryland Mothers and Babies Study, the Cigarette Restitution Fund, Johns Hopkins Medical Institutions, Johns Hopkins Center for a Livable Future and the Heinz Foundation.
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