C&EN: TODAY'S HEADLINES - Survey Documents Chemical Exposure

BETTE HILEMAN

The Centers for Disease Control & Prevention has released the most extensive assessment ever of the U.S. population’s exposure to environmental chemicals. The study reveals some progress in reducing exposures and some findings of concern.
The survey measured 116 environmental chemicals in blood and urine samples taken in 1999–2000 from some 2,500 people nationwide.

“This kind of exposure information … helps lay the critical groundwork for future research in ensuring that exposures to chemicals in the environment are not at levels that affect our health, “ CDC Director Julie L. Gerberding says.

One reassuring finding is that blood lead levels have declined. In a 1991–94 survey of 27 chemicals—CDC’s first national exposure survey—4.4% of children who were one to five years old had elevated blood lead levels, equal to or above 10 mg per deciliter. In the new survey, only 2.2% of children in this age group have elevated blood lead levels. Nevertheless, “exposure of children to lead ... remains a serious public health problem,” says Jim Pirkle, deputy director for science at CDC’s National Center for Environmental Health.

By measuring survey participants’ levels of cotinine, a metabolite of nicotine, researchers found that exposure to tobacco smoke for nonsmokers has decreased since the 1991-94 survey. However, for children, levels of the metabolite declined only 58%, whereas for adults, it fell 75%. Children are exposed to more tobacco smoke because they spend less time in smoke-free workplaces, Pirkle says.

Other chemicals that CDC scientists measured for the study included mercury, uranium, cadmium, phthalates, chlorpyrifos, and organochlorine pesticides.

CDC plans to issue an exposure survey every two years. Among other uses, the surveys will help physicians recognize unusually high levels of exposure to chemicals in patients. The complete report is available at http://www.cdc.gov/exposurereport.