1 February 2003
bearing brunt of chemical contamination, big study finds
But levels of PCBs, secondhand smoke, DDT in Americans' bodies are
lower than 10 years ago
children carry traces of some common pesticides, industrial chemicals
and other contaminants at levels twice as high as in adults, according
to the largest study ever of human exposure to environmental chemicals.
the most part, the study by the federal Centers for Disease Control
and Prevention found that exposures to the most harmful chemicals
-- including lead, DDT, PCBs and secondhand smoke -- had declined
among both adults and children from a decade ago.
officials attributed the decline to public health programs and stricter
regulations on chemical pollution. But they warned that millions
of children still faced hazardous levels of many contaminants.
of children in the study had been exposed to tobacco smoke and had
levels twice those of adults. Children also had twice the level
of industrial chemicals known as phthalates and higher levels of
a recently banned insecticide used around households, chlorpyrifos,
also known as Dursban.
eat, breathe and drink two to three times as much as adults do"
based on weight, said Dr. Richard Jackson, director of the CDC's
National Center for Environmental Health. "It's not surprising
that children's exposures will be higher from dietary and respiratory
researchers took blood and urine from 2,500 people in 1999 and 2000
and tested for 116 chemicals as part of the National Health and
Nutrition Examination Survey, which collects data on 5,000 randomly
selected people. An initial study released in 2001 looked at only
report is by far the most extensive assessment ever made of the
exposure of the U.S. population to environmental chemicals,"
said Dr. David Fleming, CDC's deputy director of science. The study
was posted Friday at www. cdc.gov/exposurereport. More than 50 separate
studies are in progress to determine the health effects of a wide
array of chemicals. These data will be used by others to determine
a reference point for comparison and to indicate where to regulate.
Environmental Protection Agency estimates that there are between
80,000 and 100,000 chemicals in commerce today.
a fair number of chemicals have been put into common commerce that
weren't adequately tested, particularly as pesticides were grandfathered
in in the early '70s and '80s," said the CDC's Jackson. It
is "important to begin to have the toxicology data when large
numbers of people are being exposed."
cautioned, however, that the presence of an environmental chemical
in a person's body doesn't by itself mean that it causes diseases.
American Chemistry Council, a manufacturers group, issued a statement
saying the CDC study would help researchers look at whether the
presence of minute levels of chemicals in the body had any health
impact. But it cautioned consumers about reading too much into the
people may jump to the conclusion that simply finding a natural
or manmade chemical in the body is cause for concern," it said.
"Scientists at the CDC warn against scaring people in this
study found a drop in three cancer-causing pollutants that persist
in the environment over long periods -- the banned pesticide DDT;
PCBs, which were once used as insulation in electrical transformers;
and dioxins, a byproduct of combustion and furnaces.
a disturbing finding, the study found that up to 10 percent of women
of child-bearing age carried toxic mercury at levels estimated by
the U.S. EPA to affect the developing fetus. Mercury, a contaminant
found in some types of fish, can damage the brain and nervous system.
study also found that Mexican Americans had levels of DDT three
times higher than non-Hispanic whites and African Americans, and
that African Americans had twice the exposure to secondhand smoke
than whites and Mexican Americans.
children, the decline in lead was notable. In the early 1990s, 4.4
percent of children ages 1 to 5 had unsafe levels, but that dropped
to 2.2 percent in 1999-2000, the study found. Lead is a major concern
because of its effects on brain development.
secondhand smoke, which was found in children at twice the levels
in adults, declined by 58 percent in children. It dropped more among
adults -- 75 percent. The CDC measured exposure to secondhand smoke
by testing for cotinine,
byproduct of nicotine after it enters the body.
officials believe children's exposure to secondhand smoke may be
high because public health efforts primarily focused on reducing
secondhand smoke in adult areas, such as in the workplace. In addition,
children may absorb more from their environment than adults.
plastics softeners that are suspected of causing cancer and developmental
harm, were found in children at twice the levels of adults. Exposure
probably comes from plastic toys, said Jim Pirkle, deputy director
for science at CDC's environmental health lab.
are also found in soaps, shampoos, hair sprays and nail polish and
are used widely in plastic food packaging, plastic clothing, detergents,
garden hoses and some pharmaceuticals.
Jane Kay at email@example.com.