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Contaminants in the Blood

A broad survey of blood samples has found that people around the world are exposed to perfluorinated chemicals, including one used to make Teflon, Stainmaster carpets, and a host of consumer and industrial products. The survey found similar levels of perfluorooctanesulfonate (PFOA) in both developing and industrialized nations. The authors suspect that consumer products used in the home may be the predominant source of PFOA exposure.

PFOA is one of many perfluorinated chemicals whose production and use has skyrocketed over the last 50 years. It has consistently been found in the blood of people from industrialized nations who live far from factories making or using the chemicals. This survey extends the findings to developing countries and builds on evidence that there may be other ways to become exposed.

To see how PFOA levels compared geographically, toxicologist Kurunthachalam Kannan of the State University of New York, Albany, who led the survey, gathered 473 blood-bank samples from the United States, Colombia, Brazil, Belgium, Italy, Poland, India, Malaysia, and Korea. His team found that U.S. levels, which ranged from 3 to 14.7 parts per billion (ppb), ranked in the middle, between those found in Korea (up to 256 ppb) and the vanishingly low levels in India--differences Kannan couldn't fully explain. Levels were not any lower in less-industrialized countries such as Colombia, the team reported online 24 July in Environmental Science and Technology. This is surprising, Kannan says, because blood levels of common contaminants such as PCBs tend to be higher in more-industrialized countries. Kannan believes that blood levels are linked to exposure to consumer products that contain PFOA, an increasingly popular hypothesis.

Consumer products may indeed be the culprits here, says University of Toronto environmental chemist Scott Mabury. But, he cautions, "there's still lots of work to be done to figure out why these compounds are so widely dispersed." The results come as the U.S. Environmental Protection Agency (EPA) is increasing its scrutiny of PFOA. Last year, a preliminary EPA risk assessment warned that PFOA might pose a developmental risk to children at levels close to those currently found in women's blood (ScienceNOW, 15 April 2003); a more complete assessment is expected this fall. In June, meanwhile, the agency also announced that it would conduct its own yearlong evaluation of PFOA-based products' fate in the environment.

Related site
EPA information on PFOA