|March 22, 2001
ATLANTA (Reuters Health) - The Centers for Disease Control and
Prevention on Wednesday released groundbreaking data about exposure
of the US population to 27 different environmental chemicals.
The data were gathered as part of the 1999 National Health and
Nutrition Examination Survey (NHANES), in which blood and urine
samples were gathered from about 5000 participants at 12 locations
throughout the US. With the exception of lead, cadmium, and
cotinine, data on exposure of the US population to these chemicals
had not previously been reported.
"I believe that this is a major step forward in assessing
exposure of the US population...to environmental chemicals--it could
be revolutionary in terms of environmental health in the United
States," Dr. Richard J. Jackson, director of the CDC's National
Center for Environmental Health, said during a telephone press
The 27 chemicals fall into four groups: metals, including lead,
mercury and cadmium; cotinine, an indicator of secondhand tobacco
smoke exposure; organophosphates, used to make pesticides; and
phthalates, widely used in industry and found in soap, shampoo,
hairspray, and nail polish, as well as in flexible plastic products.
Dr. Eric Sampson of the CDC's Environmental Laboratory noted that
the report provides new information about phthalates. "Seven major
phthalates were measured and we found that two of the
metabolites--diethyl phthalate (DEP) and dibutyl phthalate
(DBP)--are at higher levels in the population than metabolites of
other phthalates that are actually produced in higher quantities,"
he said. "We are conducting additional studies to explain these
Lead levels, which have been monitored in the US since 1976,
decreased for children aged 1 to 5 years from 2.7 micrograms per
deciliter, the geometric mean for the period 1991 to 1994, to 2.0
micrograms per deciliter. "These lower levels mean that public
health actions have been successful in decreasing children's
exposure to lead," Dr. Sampson said.
"Another exciting finding was that cotinine levels have gone down
more than 75% since the measurements taken in 1991," he commented.
Dr. Jackson emphasized that the new report concerns just one
year's worth of data, "so sample size is somewhat limited in that
regard," he said. "Ultimately data from many more locations will be
reported," he added, estimating that data on exposures to 100
chemicals will be collected and the CDC will make more detailed
assessments of exposures in different populations.
Dr. Jackson also stressed that the presence of a chemical in
blood or urine does not necessarily indicate that the chemical will
cause disease. "Additional research is required to determine whether
the levels reported are a cause for health concern," he said.
"Coming out of this report is an understanding of just how
widespread exposure to phthalates apparently is," Dr. John Balbus,
of the George Washington University School of Public Health, said at
a press conference held in response to the CDC's report.
"Women of childbearing age in particular are exposed to DBP,
which has been most clearly associated with developmental effects in
animal studies," Dr. Balbus said. "Because of these higher exposure
levels, we need to look more closely at whether the public is at
"I think most people would be surprised to know how little the
government actually knows about the level of chemicals that are in
people's bodies," he added.
In a statement released Tuesday, Sandra Tirey, assistant vice
president and co-leader of the American Chemistry Council's Public
Health Team, cautioned that "biomonitoring data alone is not an
indication that anybody's health is being harmed....The health
significance of biomonitoring data is virtually impossible to
interpret without toxicity research."
The Phthalate Esters Panel of the American Chemistry Council said
in a Wednesday press release that "the highest levels reported by
CDC indicate that the exposure levels of the US population to the
phthalate esters measured are within the safety limits set by the US
Environmental Protection Agency."
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