Sunday, 27 April 2008

The Dirty Truth About Plastic

Whoa. This is waaay disturbing - particularly since in Shanghai, The Boy and I are 100% reliant on drinking water delivered by way of large plastic bottles (no way to know how safe they are).

Hmmm... so when is Kamen's miracle water distiller available for purchase?

Extracts from the article at Discover:

"The most pressing question about plas­tic, though, may be whether daily exposure alters the health and fertility of our children and perhaps even our children’s children. It turns out that the hormonelike chemicals in plastic may remodel our cells and tissue during key stages of development, both in the womb and in early childhood. When pregnant mice are exposed to chemicals in plastic, the mammary and prostate tissue of their developing embryos proliferates abnormally, and sensitivity to hormones is forever turned up. Perhaps most disturbing is the significant increase in chromosomal abnormalities in the eggs forming in those embryos. Those are the eggs that will make the next generation. Thus, if the worst-case scenario proves true, early exposure to plastic can reshape not just our children but their children, too.

...Two in particular stand out: bisphenol A (or BPA, used in polycarbonates and resins) and phthalates (used to make plastic soft and pliable). Both upset the way certain hormones function in the body, earning them the designation endocrine disrupters. They are both now the subject of fierce scientific and public scrutiny.

... If there is one point on which many scientists agree, it is the risk to the developing fetus and the young child. “At least a dozen studies have shown the effects of phthalates on human reproduction,” says University of Rochester epidemiologist and biostatistician Shanna Swan, the lead author of a much-cited study that showed higher exposure to some phthalates in mothers correlates with reduced “anogenital distance” in newborn boys. Biologists recognize a reduction in the length between the anus and the sex organ as an external marker of feminization, easily measured because it is typically twice as long in males as in females.

... Last November a panel sponsored by the National Institutes of Health (NIH) determined that there was at least “some concern” about BPA’s effect on the fetal and infant brain. Around the same time, the Centers for Disease Control reported that researchers there had found BPA—the United States produces 6 billion pounds of it yearly—in 93 percent of urine samples from 2,500 Americans aged 6 to 85. Children under age 12 had the highest concentrations.

... In other research, by reproductive biologist Patricia Hunt of Washington State University, female mice exposed to low amounts of BPA in the womb—amounts deemed “environmentally relevant”—had high levels of genetic errors in the eggs they produced. Worse still, the genetic errors in those eggs led to chromosome abnormalities in 40 percent of the next generation’s eggs. That is 20 times the incidence of such abnormalities in unexposed mice. How might this relate to human risk? According to commentators reviewing Hunt’s work in PLoS Genetics, the answers will be hard to tease out: Nearly one in five human pregnancies ends in miscarriage, half of which are due to chromosomal abnormalities. Abnormalities in a woman’s eggs increase as she ages, and more women are having children at a later age. “A proper study of this problem,” they wrote, “would require assessing the woman’s level of chemical exposure now and maintaining those data for two to three decades,” tracking the abnormalities in her children and grandchildren.

... Phthalate studies show similarly dramatic effects. When pregnant rats are exposed to high doses of phthalates, their male offspring are born with deformed genitalia. In 2005 Shanna Swan published the first study that looked for evidence of an obvious effect among boys. In 134 boys aged 2 months to 30 months, she found that sons whose mothers had higher levels of certain phthalates in their urine had a shorter distance between the anus and the penis. These boys were also likelier to have smaller penises and incompletely descended testicles. About one-quarter of American women have the higher phthalate levels she found in her study. This was particularly evident among women working in poorly ventilated nail salons, where one especially harmful phthalate, DBP, is released.

... Phthalate exposure does not come just from moms. A new study gives evidence that infants and toddlers exposed to lotions, shampoos, and powders with phthalates may have up to four times as much of it in their urine as those whose parents do not use the products. The study, just published in Pediatrics by Sheela Sathyanarayana of the University of Washington, looked at 163 children between the ages of 2 months and 28 months between the years 2000 and 2005. The results were alarming, not least because manufacturers are not required to list phthalates as ingredients on labels.

... regulation of synthetic estrogens as a class seems far off. BPA alone is “worth at least a million dollars every hour,” Welshons says. “And that figure is conservative. I’m surprised the chemical industry hasn’t tried to blow up our labs.”

In 1989 little was known about synthetic chemicals in everyday plastics and how they mimicked estrogens. Ana Soto, professor of cellular biology at Tufts University School of Medicine, and her colleagues were studying the effects of estrogen on a breast cancer cell line. “Suddenly all the cancer cells were proliferating maximally, whether they were being grown in a medium with estrogen or not,” Soto recalls. “We thought that somebody must have opened a bottle of the female hormone estradiol in the wrong place. We scrubbed the whole room, we bought new batches of everything, and the cells kept proliferating. So we began one by one to replace and substitute our equipment, and we finally found the contamination in tubes storing a component of the medium. The tube manufacturer had changed its formula, with the best intention of rendering the tubes more impact resistant. They said the new chemical was a trade secret. So we analyzed it ourselves, and it turned out to be nonylphenol. We injected the chemical into rats and demonstrated that it makes the epithelial lining of the uterus proliferate—a sign of its being an estrogen.” Nonylphenol is also a component in some detergents and other products, and its presence in British streams has been linked to the feminization of fish.

In 1998 another synthetic estrogen leached from animal cages and bottles in a different lab—this was the now-infamous BPA. Patricia Hunt (then working at Case Western Reserve University) was studying the endocrine environment of the aging ovary in mice. Suddenly, as in Soto’s lab, “our control data went nuts,” Hunt says. “We saw chromosomal abnormalities that would lead to pregnancy loss and birth defects. It turned out that all of our cages and water bottles were contaminated by the BPA in the polycarbonate plastic, which was being sterilized at high temperatures. We set about proving this contamination was coming from the water bottles and cages.” They published that work in 2003. In 2007 Hunt and her colleagues published a paper in PLoS Genetics demonstrating that BPA exposure in utero disrupts the earliest stages of egg development. The fetuses of pregnant mice exposed to low doses of BPA, Hunt says, had “gross aberrations. We were stunned to see the effects of this estrogenic substance.”

... “We have no choice,” Soto says. “If reproduction is being affected, the survival of the species is compromised. Sooner or later we have to regulate it. And what constitutes proof? In the 1950s a woman’s lifetime risk of breast cancer was 1 in 22; today it’s 1 in 7. A threefold increase cannot be genetic, it is most likely environmental, and many of us believe it is due to endocrine disrupters. To know whether fetal exposure to BPA is producing breast cancer in humans, you have to collect blood from the mother and the newborn, bank it, and follow that cohort for many, many decades. One generation of researchers can’t do it. This is painful, and the public should know about it.”

Full article here.

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