Are poisons lurking in human bodies? (On First Reading).

Did you ever wonder what toxic pollutants might be flowing through your veins?

The Centers for Disease Control and Prevention (CDC) answers this question with the release of its first "National Report on Human Exposure to Environmental Chemicals."

The new data, which provide information on concentrations of 27 toxic substances in the U.S. population (more than 100 will be tracked in the future), is part of the National Health and Nutrition Examination Survey, the nation's most comprehensive study.

"This new resource is a significant development in the field of environmental health," says Health and Human Services Secretary Tommy G. Thompson. "It will help us to better track the exposures of Americans to chemicals in the environment and to measure the effectiveness of our public health efforts."

A team of health personnel and laboratory technicians using high-tech, state-of-the-art equipment, staff the mobile examination centers.

The exposure report provides legislators, policymakers and the general public with the first accurate glimpse of the chemicals Americans are exposed to, and will be a step toward making the connection between health and the environment. This first report includes data on substances such as lead, mercury, phthalates (chemicals used in soft plastics and cosmetics), second-hand smoke and pesticides.

Knowing what chemicals Americans are exposed to will determine the hazards and help public health officials and legislators develop sound policies. This type of monitoring has already proved vital in shaping lead poisoning prevention policy.

The study was used to show that the number of Americans with high levels of lead in their blood dropped by 78 percent between 1980 and 1984, demonstrating that prevention efforts were working.

"The good news is that blood lead levels continue to decline among children overall," says Eric Sampson of CDC's Environmental Laboratory and a co-author of the report. "However, other data show that children living in environments placing them at high risk for lead exposure remain a major public health concern."

The exposure report data shows that both lead and cotinine (a marker for second-hand cigarette smoke) levels decreased significantly, documenting that no-smoking policies and lead poisoning prevention work.

The report also showed that certain portions of the population may not be adequately protected from mercury and phthalates. Mercury is found in fish, and its main source is coal-fired power plants.

Phthalates are common in cosmetics, shampoo and soaps. Although the risks posed by exposure to them are unknown, some research suggests that phthalates may be linked to developmental and reproductive disorders, such as reduced sperm counts, testicular abnormalities and early puberty.

The report can be found at: www.cdc.gov/nceh/dls/report