Washington Post
1 February 2003

Blood Levels of Lead Down, CDC Report Finds Study Finds Children Have More Exposure to a Tobacco-Related Chemical Than Adults

By Eric Pianin

Levels of lead and nicotine-related chemicals in humans have been sharply reduced over the past decade, even as Americans were exposed to an unprecedented array of toxic and potentially health-threatening chemicals, according to a government study released yesterday.

But in a surprising twist, researchers for the federal Centers for Disease Control and Prevention found that levels of a nicotine-related chemical called cotinine in young children were more than twice the levels found in nonsmoking adults.

Levels of tobacco-related chemicals in nonsmoking adults dropped by 75 percent from the early to the late 1990s, but decreased by 58 percent in children and 55 percent in adolescents, the study showed. The survey was not designed to determine whether the presence of these or other chemicals had harmful health effects.

Experts said the discrepancy is the result of physiological differences in adults and children, and the fact that anti-tobacco campaigns are largely geared to adults in the workplace or in restaurants -- and that far less was done to discourage parents from smoking at home around children.

"What we are looking at now is that we have a group we need to specifically target and think of new things to do to reduce their exposure" to secondhand smoke, said Jim Pirkle, deputy director of science for the CDC's National Center for Environmental Health.

The $6.5 million, two-year study tested the blood and urine of 2,500 volunteers. It is the most exhaustive and detailed survey undertaken to determine the extent of human exposure to potentially harmful toxic chemicals.

The study found that the proportion of young children with elevated levels of lead dropped by half during the past decade -- from 4.4 percent to 2.2 percent of children 5 and younger.

But officials said the overall numbers do not reflect the reality of environmental "hotspots." They said that as many as 20 percent of young children living in poverty suffer from levels of lead high enough to affect their nervous systems and intellectual growth.

The study uncovered other troubling evidence: Of the 116 chemicals for which the volunteers were tested, positive results were found for 89 chemicals, including PCBs, dioxins, phthalates, selected organophosphate pesticides, herbicides, pest repellents and disinfectants.

Federal environmental agencies have conducted risk assessments on lead, tobacco, cadmium, mercury, certain pesticides and other chemicals, but most of the chemicals have been tested for toxicity only in animals.

CDC officials said more research is needed on specific chemicals and their effects, and the latest report will provide an invaluable baseline for future efforts to identify and treat victims of exposure to dangerous compounds.

Although the study highlighted the pervasiveness of toxic chemical compounds, scientists cannot say whether trace levels of many of these chemicals result in cancer or other diseases.

"Just because a chemical is measured in blood and urine doesn't mean that it causes disease," said Richard Jackson, director of the CDC's National Center for Environmental Health.

Environmental activists and chemical industry officials, including representatives of the American Chemistry Council, said the report would help in the long-term effort to identify and deal with dangerous chemical compounds in the atmosphere that may be associated with disease.

"I certainly do empathize with people with disease," said Jay J. Vroom, president of CropLife America, which represents pesticide manufacturers. "But the thing we have to keep reminding the American public is that every one of those compounds found in blood and urine resulted from commercial products that benefited society . . . and nothing is risk-free."

Still, hundreds of studies have shown harmful effects from low-dose exposures to PCBs, DDT, dioxin, mercury and other chemicals.

A separate study released this week of a tiny, handpicked sample of nine men and women found trace amounts of an average of 91 chemical compounds in each one.

The study by Mount Sinai School of Medicine in New York, along with the advocacy groups Environmental Working Group and Commonweal, tested the blood and urine of the volunteers for 210 chemicals -- the largest suite of industrial chemicals ever surveyed.

Andrea Martin, 56, of Sausalito, Calif., a breast cancer survivor and founder of the Breast Cancer Fund, was found to have traces of 95 chemical compounds in her body, including 59 potentially cancer-causing contaminants. A year ago, doctors discovered a cancerous tumor on her brain.

"No one can say whether that mixture of chemicals -- that cocktail in me -- produced this brain cancer, but no one can say it hasn't," she said this week. "I have a right to know what the effects of these chemicals are."