[Pharmwaste] Common chemicals pose danger for fetuses,
Laurie.Tenace at dep.state.fl.us
Fri May 25 11:33:03 EDT 2007
Common chemicals pose danger for fetuses, scientists warn
Exposure to toxic materials in the womb can cause health problems later in
life, an international panel declares.
By Marla Cone, Times Staff Writer
May 25, 2007
In a strongly worded declaration, many of the world's leading environmental
scientists warned Thursday that exposure to common chemicals makes babies
more likely to develop an array of health problems later in life, including
diabetes, attention deficit disorders, prostate cancer, fertility problems,
thyroid disorders and even obesity.
The declaration by about 200 scientists from five continents amounts to a
vote of confidence in a growing body of evidence that humans are vulnerable
to long-term harm from toxic exposures in the womb and during their first
Convening in the Faroe Islands in the North Atlantic, toxicologists,
pediatricians, epidemiologists and other experts warned that when fetuses and
newborns encounter various toxic substances, growth of critical organs and
functions can be skewed. In a process called "fetal programming," the
children then are susceptible to diseases later in life - and perhaps could
even pass on those altered traits to their children and grandchildren.
The scientists' statement also contained a rare international call to action.
The effort was led by Dr. Philippe Grandjean of Harvard University and the
University of Southern Denmark, and Dr. Pal Weihe of the Faroese Hospital
System, who have spent more than 20 years studying children exposed to
Many governmental agencies and industry groups, particularly in the United
States, have said there is no or little human evidence to support concerns
about most toxic residue in air, water, food and consumer products. About
80,000 chemicals are registered in the United States.
Yet the scientists urged leaders not to wait for more scientific certainty
and recommended that governments revise regulations and procedures to take
into account subtle effects on fetal and infant development.
Chemicals with evidence of developmental effects include compounds in
plastics, cosmetics and pesticides.
"Given the ubiquitous exposure to many environmental toxicants, there needs
to be renewed efforts to prevent harm. Such prevention should not await
detailed evidence on individual hazards," the scientists wrote in the
The scientists are particularly concerned that the newest animal research
suggests that chemicals can alter gene expression - turning on or off genes
that predispose people to disease. Although the DNA itself would not be
altered, such genetic misfires in the womb may be permanent, and all
subsequent generations could be at greater risk of diseases too.
"Toxic exposures to chemical pollutants during these windows of increased
susceptibility can cause disease and disability in childhood and across the
entire span of human life," the scientists concluded.
The "Barker hypothesis," conceived by a British scientist in 1992, says human
fetuses are "programmed" for diseases by their early environment. The
scientists concluded that this is now well-documented for toxic exposures by
a large collection of animal experiments and some human data.
"A sad aspect with many of these prenatal exposures is that they leave the
mother unscathed while causing injury to her fetus," said Dr. Philip
Landrigan, a pediatrician who chairs the Mount Sinai School of Medicine's
Department of Community and Preventive Medicine. He was one of the
In a more optimistic vein, the researchers said that if contaminants do play
a big role in human health problems, some diseases could be prevented.
"Reducing exposure would lead to tremendous benefits," said Dr. Bruce
Lanphear, director of the Environmental Health Center at Cincinnati
Children's Hospital Medical Center. "We shouldn't wait for an epidemic to
fully mature before we develop policies to protect children."
For centuries, the basic rule of toxicology has been "the dose makes the
poison." Now, the scientists say "the timing makes the poison" - in other
words, when a toxic exposure occurs is as important as the amount people are
The fetus "is extraordinarily susceptible to perturbation of the intrauterine
environment," they wrote.
The growing brain is the most sensitive. Mothers' exposure to mercury and
polychlorinated biphenyls (PCBs) in fish and other seafood can cause slight
declines in a child's IQ and motor skills. In addition, early exposure to
pesticides might trigger Parkinson's and Alzheimer's diseases.
Also, children exposed to lead, organophosphate pesticides or cigarette smoke
have greater risk of attention deficit hyperactivity disorder. One of every
three cases - or an estimated 560,000 children in the United States - can be
attributed to lead exposure or prenatal tobacco smoke exposure, Lanphear
reported in a study published in December.
The immune, reproductive and cardiovascular systems also are vulnerable to
early damage. Children exposed prenatally to PCBs have a high rate of
infections and weak response to vaccinations. Many chemicals also can mimic
hormones, and in animal tests, they feminize newborns, lowering sperm counts
and promoting prostate, testicular, uterine and breast cancers.
In the newest area of research, metabolic systems, which control how
nutrients are converted into energy, have been altered by chemicals
administered in animal experiments - changes that may contribute to obesity
"These adverse effects have been linked to chemical pollutants at realistic
human exposure levels similar to those occurring from environmental sources,"
the scientists wrote.
Among the risky chemicals they named are bisphenol A, found in polycarbonate
plastic food and water containers; the pesticides atrazine, vinclozolin and
DDT; lead; mercury; phthalates used in some cosmetics and soft plastics;
brominated flame retardants; arsenic, which contaminates some water supplies;
and PCBs, banned but ubiquitous, particularly in fish.
Some of the chemicals have been regulated in the United States, but many have
not. Moreover, the scientists said, tests for developmental effects are not
routinely required, so "the potential for such effects is therefore not
necessarily considered in decisions on safety levels of environmental
There is "an incredible gap," Landrigan said, because 80% of major chemicals
in commerce have never been tested to see if they damage early development.
The conference was funded by the World Health Organization, National
Institutes of Health, European Environment Agency and the Centers for Disease
Control and Prevention.
Denmark's Faroe Islands, just south of the Arctic Circle, were the venue
because the region is home to the longest-running human experiment analyzing
prenatal toxic exposure. Since 1986, Grandjean and Weihe have tracked Faroese
children from the womb to adolescence to monitor neurological effects of
mercury in seafood. Their findings prompted U.S. advisories that children and
women of childbearing age avoid swordfish and other highly contaminated fish.
In addition to Landrigan, three Californians and six other U.S. scientists
served on the 28-member committee that wrote the consensus: Brenda Eskenazi
of UC Berkeley, Irva Hertz-Picciotto of UC Davis, Beate Ritz of UCLA, Jerry
Heindel and Kimberly Gray of the National Institute of Environmental Health
Sciences, Larry Needham of the CDC, Terry Huang of the National Institute of
Child Health and Human Development, David Bellinger of Harvard University and
Howard Hu of the University of Michigan.
Laurie J. Tenace
Florida Department of Environmental Protection
2600 Blair Stone Road, MS 4555
Tallahassee, Florida 32399-2400
PH: (850) 245-8759
FAX: (850) 245-8811
Laurie.Tenace at dep.state.fl.us
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