Dozens of Chemicals Found in Most Americans' Bodies
The concentration is especially high in children, a national study says. But
experts aren't
sure what the health effects are.

By Marla Cone, Times Staff Writer

In the largest study of chemical exposure ever conducted on human beings, the
U.S.
Centers for Disease Control and Prevention reported Thursday that most American
children and adults were carrying in their bodies dozens of pesticides and toxic
compounds used in consumer products, many of them linked to potential health
threats.

The report documented bigger doses in children than in adults of many chemicals,
including some pyrethroids, which are in virtually every household pesticide,
and
phthalates, which are found in nail polish and other beauty products as well as
in soft
plastics.


The CDC's director, Dr. Julie L. Gerberding, called the national exposure report
— the third
in an assessment that is released biennially — a breakthrough that would help
public
health officials home in on the most important compounds to which Americans are
routinely exposed.

The latest installment, which looked for 148 toxic compounds in the urine and
blood of
about 2,400 people age 6 and older in 2000 and 2001, is "the largest and most
comprehensive report of its kind ever released anywhere by anyone," Gerberding
said.
Findings were broken down by age group and race.

At Thursday's news conference, CDC officials emphasized the good news: Steep
declines
were found in children's exposure to lead and secondhand cigarette smoke.

Lead levels in children have dropped significantly over several years, which
Gerberding
called an "astonishing public health achievement" attributable largely to its
removal from
gasoline and paint.

About 1.6% of young children tested from 1999 to 2002 had elevated levels of
lead, which
could lower their intelligence and damage their brains, compared with 88.2% in
the late
1970s and 4.4% in the early 1990s.

But the discovery of more than 100 other substances in humans, particularly
children,
distressed environmental health experts.

"The report in general shows that people — kids and adults — are exposed to
things that
aren't intended to be in their body," said Dr. Jerome A. Paulson, an associate
professor of
pediatrics at the George Washington University School of Medicine and Health
Sciences
who specializes in children's environmental health. "In and of itself, that is a
concern.
Whether it's harmful or not we can't tell from this particular study."

The new data in the 475-page report reveal how "we have fouled our own nest,"
Paulson
said. "We contaminated the environment sufficiently that there are measurable
amounts of
potentially toxic substances in people — kids and adults."

The CDC did not try to gauge the health threat the chemicals might pose. A
measurable
amount of a compound in a person's body does not mean it causes disease or other
damage, the agency noted.

For many compounds in the report, experts have little information on what
amounts may
be harmful or what they may do in combination.

"We are really at the beginning of a very complicated journey to understand the
thousands
of substances we are exposed to," said Thomas Burke, associate professor at the
Johns
Hopkins Bloomberg School of Public Health.

The discovery of pyrethroids in most people is especially important, as no one
had looked
for them in the human body before. Pyrethroids are synthetic versions of natural
compounds found in flowers, and they have been considered safer than older
pesticides,
such as DDT and chlordane, that build up in the environment and have been banned
in the
United States.

But in high doses, pyrethroids are toxic to the nervous system. They are the
second most
common class of pesticides that result in poisoning. At low doses, they might
alter
hormones. The compounds are used in large volumes in farm and household
pesticides
and are sprayed by public agencies to kill mosquitoes.

Pyrethroids "were a step forward [from DDT and other banned pesticides], but now
we're
beginning to understand that while they don't persist in the environment, many
of us are
exposed," Burke said. "We don't quite know what those levels mean."

Eleven of 12 phthalates tested were higher in children than adults. All of the
phthalates
but one are used in fragrances. In animal tests, and in one recent study of
human babies,
some of the compounds have been shown to alter male reproductive organs or to
feminize
hormones.

Representatives of the chemical and pesticide industries praised the study,
saying that
human biomonitoring is the best available tool to measure exposure. They echoed
the
CDC in saying that discovery of the chemicals in the human body did not
automatically
mean they posed a threat.

The report demonstrates "that exposure to these man-made and natural substances
is
extremely low," said American Chemistry Council spokesman Chris VandenHeuvel.

The CDC's Gerberding said that "for the vast majority" of the 148 chemicals in
the report,
"we have no evidence of health effects."

Many toxicologists and environmental scientists disagree.

Studies of animals, and in some cases people, suggest that most of the compounds
can
affect the brain, hormones, reproductive system or the immune system, or that
they are
linked to cancer. "These are some bad actors," Burke said.

Many of the compounds have not been studied sufficiently to know what happens
with
chronic exposure to low doses. "No evidence of health effects does not imply
that they are
not harmful," Paulson said. "It just means we don't know one way or another."

Environmental groups have called for U.S. law to require chemical companies to
test
industrial compounds more comprehensively, a proposal similar to one that the
European
Parliament is to debate in the fall.

The evidence that many contaminants amass in children more than in adults could
mean
that they are exposed to larger amounts — perhaps from crawling, breathing more
rapidly
or putting items in their mouths — or that their bodies are less able to cope
with or
metabolize them.

In the womb and in the first two years after birth, children undergo
extraordinary cell
growth, from brain neurons to immune cells, so there are more opportunities for
toxic
compounds to disrupt the cells, Paulson said. Animal tests show that fetuses and
newborns are the most susceptible to harm from many chemicals.

In the CDC study, one of every 18 women of childbearing age, or 5.7%, had
mercury that
exceeded the level that the U.S. Environmental Protection Agency deemed safe to
a
developing fetus.

Tests on schoolchildren show that mercury exposure in the womb can lower IQs,
with
memory and vocabulary particularly impaired.

The CDC plans to expand the national chemical report to more than 300 compounds
in
two years and about 500 in four years. An estimated 80,000 chemicals are in
commercial
use today.