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Last Updated: Apr 16, 2008 - 5:52:06 PM |
WEDNESDAY JAN 30, 2008 (Foodconsumer.org) -- Polycarbonate plastic bottles, old or new, release a toxic chemical known as bisphenol A or BPA in short much faster in hot water than in cool or temperate liquid, according to the University of Cincinnati (UC) scientists who published their findings in the Jan. 30, 2008 issue of the journal
Toxicology Letters.
Scott Belcher, PhD, UC associate professor of pharmacology and cell biophysics and colleagues found polycarbonate drinking bottles released BPA, an environmental estrogen, up to 55 times faster when exposed to boiling hot water.
This is the case for both used and new polycarbonate drinking bottles/containers. Belcher said bottles used for as long as nine years were the same as the new bottles when it comes to the rate of BPA release.
"Previous studies have shown that if you repeatedly scrub, dish-wash and boil polycarbonate baby bottles, they release BPA. That tells us that BPA can migrate from various polycarbonate plastics," explains Belcher, corresponding study author.
"But we wanted to know if 'normal' use caused increased release from something that we all use, and to identify what was the most important factor that impacts release."
BPA, one man-made chemical, disrupts the function of the endocrine system by mimicking the role of the body’s natural hormones.
Among others, bisphenol A can initiate the proliferation of androgen-independent prostate cancer cells at extremely low exposure levels. It can also sensitize breast tissue increasing risk of breast cancer, according to early studies.
Bisphenol is used as a key monomer in production of polycarbonate plastic and epoxy resins. It is also used as an antioxidant in plasticizers and as a polymerization inhibitor in polyvinyl chloride, the majority of which is used as construction material.
Polycarbonate plastic is widely used in products such as reusable water bottles, food can linings, water pipes and dental sealants. This chemical has been shown to affect reproduction and brain development in animal studies. Studies also found that prenatal exposure to the chemical has the greatest impact.
"There is a large body of scientific evidence demonstrating the harmful effects of very small amounts of BPA in laboratory and animal studies, but little clinical evidence related to humans," explains Belcher. "There is a very strong suspicion in the scientific community, however, that this chemical has harmful effects on humans."
In the study, Belcher and team analyzed bisphenol A release from used polycarbonate water bottles obtained from a local climbing gym and new bottles of the same brand purchased from an outdoor retail supplier.
All bottles were tested in a way to simulate normal usage during backpacking, mountaineering and other outdoor adventure activities.
The researchers found the rates of releasing of bisphenol A from drinking bottles, new or old, were the same in the cool or temperate water. But boiling water increased the release 15 to 55 times, according to the authors.
In comparison, prior to boiling water treatment, the bottles released 0.2 to 0.8 nanograms of bisphenol A per hour compared to 8 to 32 nanograms per hour after exposure to boiling water.
Although it is not certain what exact effect bisphenol A poses on human health, health conscious consumers may want to consider minimizing their exposure to this chemical. Polycarbonate plastic looks clean and transparent and is used to bottle water or foods.
© 2004-2008 by foodconsumer.org unless otherwise specified
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