Study Details Americans' Chemical Exposure
Many Exposures Down, but Health Effects Uncertain
Researchers also recorded falling levels of cotinine, a blood marker indicating exposure to secondhand smoke.
Gerberding says the CDC found an "astonishing reduction" in the chemical, suggesting that laws limiting smoking in buildings are having a positive effect.
Compared with average levels in 1988-1991, cotinine levels measured in 1999-2002 have decreased 68% in children, 69% in teens, and nearly 75% in adults, according to a news release.
But the drops were largely limited to whites. Some populations remain at risk. The study shows that blacks have levels twice as high as whites and Mexican-Americans.
Researchers take the results to mean that blacks are either being exposed to more secondhand smoke or that they metabolize nicotine differently than do whites, she says.
They also find that while levels of cotinine are decreasing, levels in children were twice as high as adults.
The study also shows low but relatively widespread exposure to phthalates, a class of chemicals found in cosmetics, plastics, and many plastic-coated food packages. The chemicals are known to affect hormone-producing organs and can cause liver and testicular damage in lab animals.
They find that half of adolescents between 12 to 19 years old had phthalates measurable in their urine, though researchers said they still don't know what the health effects are. More research is needed.
The report states that there is very limited scientific information available on potential human health effects of phthalates.
"We have reason now to look further" at the possible health effects of Americans' exposure to the chemicals, Gerberding says.