By Karen F. Schmidt for Science & Spirit magazine.
When Kim Hooper gives a public talk about his work at the California Department of Toxic Substances Control, he flashes a slide of his baby granddaughter. “We’ve given her the best genes we can, but what about her
environment?” he asks the audience. “Already she’s had an early experience
far different than my own.” After all, Hooper points out, her life in the
womb began with exposure to myriad chemicals that weren’t around sixty-five years ago.
It’s a reality that makes Hooper and many others nervous. Today, about
2,500 different chemicals are used in high volume, but basic information
about their potential effects on human development is still being compiled.
Many toxic villains have been unmasked in the last three decades, including
DDT, PCBs, dioxins, lead, mercury, and more recently, phthalates
(plasticizers) and PBDEs (flame retardants). As researchers use new tools
for measuring trace levels of contaminants in our bodies, the issue of
chemical safety is again in the spotlight. Studies using “biomonitoring”-the
testing of body tissues and fluids-are revealing that we all harbor a
cocktail of chemicals, some of which were banned long ago.
Although it’s difficult to know whether the pollutants in our tissues
are causing harm, we do know where to look for the first signs of trouble.
“Fetuses are the population we think are the most sensitive to chemical
pollutants,” says Hooper. That’s because a small disturbance in the highly
choreographed process of development can have profound and long-lasting
effects on a baby, showing up immediately as birth defects or later as
subtle dysfunctions of the nervous, immune, and reproductive systems.
Scientists believe that environmental factors play a role in at least three
percent and as much as twenty-five percent of all developmental defects in
children, according to a National Academy of Sciences report published in
2000.
Although the placenta was once thought to protect the fetus, researchers now know that many harmful substances-drugs, alcohol, toxic byproducts from cigarette smoke-pass through. Recent evidence suggests the chemicals a pregnant woman is exposed to in her environment can and do reach her fetus, Hooper says. Even chemicals encountered years ago can come back to haunt; for instance, DDT and PCBs stored in fat tissues slowly trickle into the bloodstream. But there are also plenty of new contaminants to deal with as women of childbearing age ingest mercury in their tuna fish sandwiches, breathe solvents wafting out of cosmetics, and absorb particles
coated with flame retardants while sitting on treated couch cushions. The
big question is: How much is reaching their babies?
As part of a study investigating fetal exposures to flame retardants, Jane Williams, director
of California Communities Against Toxics, is recruiting 120 new mothers to
give breast milk samples, which she sends to Hooper’s lab group in Berkeley
for analysis for PBDEs. The chemicals- which have been added to everything
from electronics to drapery to vehicle interiors- have recently turned up in
house dust, river sediment, foods from the grocery store, and wildlife, as
well as people. Laboratory studies of mice found that low doses of PBDEs
caused offspring to suffer permanent defects in their ability to learn and
remember, and rats showed delayed sexual development. Since a fetus’s
exposure is generally the same as the mother’s, Williams says the early
breast milk samples will reveal the dose of PBDEs these California babies
got in the womb.
+ Full story here:
http://www.science-spirit.org/articles/newsdetail.cfm?item_id=527