Monday, January 15, 2007

"scrambling eggs in plastic bottles"

I must admit, I distrust people who carry a Nalg around everywhere they go. I mean i know water is good and all, but do you really need 2L of water everywhere you go? Isn't that what water fountains are for? Can you survive an hour in class without giving yourself a kidney failure and a water intoxication? Ok, at least it cuts down on disposable plastic bottle waste. I dislike people who pay 2$ for 500ml of tap water even more. Well now there is even more of a reason to ditch the Nalg, and other BPA-containing plastics. Bisphenol-A, an estrogen mimic screws up meiosis in mammals, at environmental levels: "We are exposed to BPA daily; it is a component of polycarbonate plastics, resins lining food/beverage containers, and additives in a variety of consumer products. More than 6 billion pounds are produced worldwide annually, and several studies have reported levels of BPA in human tissues in the parts per billion range." I mean it's bad enough that humans have miscarriage rates of nearly 20% compared to drosophila with 0.01%, now we have to worry about all these environmental estrogens: "BPA-induced damage to meiotic pairing and synapsis observed in mice by Hunt and her collaborators in the new study would not manifest itself for two generations. Thus, at least some of the effects of exposing a 26-year-old woman to chemicals such as BPA might take 20–30 years to manifest themselves in her grandchildren".
This paper in PLOS goes into even more details in the mechanisms: "In contrast, the studies described herein reveal an effect of BPA on meiotic chromosome segregation by a second, and completely independent, mechanism, that is,by disturbing synapsis and recombination between homologs in the fetal ovary. The finding that unexposed ERβ-null females exhibit a similar phenotype—and that the phenotype cannot be enhanced by BPA exposure—suggests that BPA exerts its effects on the fetal ovary by interfering with ERβ-mediated cellular responses."


Bayman said...

Those plastics seems pretty much of it are people actually eating?

Anonymous Coward said...

That being said there might be some bonuses to having estrogen mimics in the environment...

Anonymous Coward said...

Check out the nalgene link from the post. They link to ressources on BPA, all of which say stuff like "Bisphenol A is an industrial chemical used primarily to make polycarbonate plastic and epoxy resins – both of which are used in countless applications that make our lives easier, healthier and safer, each and every day."

or undermine the article i linked too " * The study has not been replicated by other scientists.
* Comprehensive, large-scale studies (while they may in theory have failed to detect increased oocyte chromosomal abnormalities) have not shown any increase in actual birth defects.
* Previous studies appearing to show BPA effects have not been reproducible.
* The single study by Hunt is unlikely to change the prevailing weight of scientific evidence, which the FDA and other scientific bodies say show no risk from "environmental endocrine disruptors."
* Health effects in humans are probably even less likely than health effects in mice, since a recent study (by Volkel et al) suggests that BPA is far more rapidly and completely metabolized in humans than in rodents, decreasing the odds of it doing damage by lingering in the body.
* Humans are not routinely exposed to the large amounts of the chemical that the mice were. "