American Bodies Harbor Some Suspicious Chemicals
March 21, 2001 -- Thanks to advances in technology, scientists
are now able to get a much more accurate picture of how many substances in the
environment accumulate in the human body -- and at what levels. The findings
are mixed: Levels of lead and tobacco-related chemicals have dropped
substantially in recent years, but a chemical used in soap and cosmetics is
The complete findings were released today by the CDC. The CDC
obtained the information in 1999 by measuring blood and urine levels of 27
chemicals in people from 12 U.S. locations.
Of these substances, 24 were measured for the first time, and
three -- lead, cadmium, and cotinine -- have been measured previously. The new
data will serve as a yardstick for comparing future tests.
Researchers tracked four categories of exposures: metals (such
as lead, mercury, and cadmium), tobacco smoke, organophosphate pesticides, and
phthalates (compounds used in soap, shampoo, hairspray, nail polish, and
flexible plastics). In the future, they plan to add more environmental
chemicals to the list, with the goal of reaching 100 in four years. Ultimately,
they will break the findings down by age, sex, race, ethnicity, income level,
and urban/rural residence status of the participants.
Among the positive findings: Efforts to ban public smoking seem
to have resulted in a measurable reduction in harmful tobacco smoke exposure.
Levels of cotinine, the chemical left over after the body breaks down tobacco,
decreased fourfold in 1999, the report says, when compared with data from prior
years. Also, lead levels in children continued to decline in 1999, the data
These success stories are important to note, says Eric Sampson,
PhD, of the CDC's Environmental Laboratory.
"Blood lead levels for children aged 5 and younger keep
going down, [showing that we are] successful in limiting children's exposure to
lead," he says. Nevertheless, he warns, lead poisoning among children is
still a major concern, especially for those who live in homes built before 1950
and those exposed to lead-contaminated dust.
In a bit of a surprise, blood levels of two of the seven
phthalates measured -- diethyl phthalate (DEP) and dibutyl phthalate (DBP) --
were found to be higher than levels of other phthalates that are produced in
greater quantity. Further research is needed to explain this finding,