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It seems that our exposure to Bisphenol A, may be much greater than was previously assumed. Bisphenol A is an endocrine disrupter and can have a drastic effect on the endocrine system, especially in infants and children.
David Biello writes an excellent article in “Scientific American”:Plastic (Not) Fantastic: Food Containers Leach a Potentially Harmful Chemical
The U.S. Centers for Disease Control (CDC) found traces of BPA in nearly all of the urine samples it collected in 2004 as part of an effort to gauge the prevalence of various chemicals in the human body. It appeared at levels ranging from 33 to 80 nanograms (a nanogram is one billionth of a gram) per kilogram of body weight in any given day, levels 1,000 times lower than the 50 micrograms (one millionth of a gram) per kilogram of bodyweight per day considered safe by the U.S. Environmental Protection Agency (EPA) and the European Union’s (E.U.) European Food Safety Authority (EFSA).
This seems all well and good, the levels in human urine are less than the arbitrarily defined level deemed harmful by the EPA. I say arbitrarily defined as the more subtle, affects of Bisphenol A (sperm counts, developmenal anomalies, cancer rates i.e. non-lethal effects.) were examined. However, almost ALL urine samples had Bisphenol A. Further, it seems that humans can degrade Bisphenol A quickly.
Studies suggest that BPA does not linger in the body for more than a few days because, once ingested, it is broken down into glucuronide, a waste product that is easily excreted. Yet, the CDC found glucuronide in most urine samples, suggesting constant exposure to it. “There is low-level exposure but regular low-level exposure,” says chemist Steven Hentges, executive director of the polycarbonate / BPA global group of the American Chemistry Council. “It presumably is in our diet.”
A recent report in the journal Reproductive Toxicology found that humans must be exposed to levels of BPA at least 10 times what the EPA has deemed safe because of the amount of the chemical detected in tissue and blood samples. “If, as some evidence indicates, humans metabolize BPA more rapidly than rodents,” wrote study author Laura Vandenberg, a developmental biologist at Tufts University in Boston, “then human daily exposure would have to be even higher to be sufficient to produce the levels observed in human serum.”
The CDC data shows that 93 percent of 2,157 people between the ages of six and 85 tested had detectable levels of BPA’s by-product in their urine. “Children had higher levels than adolescents and adolescents had higher levels than adults,” says endocrinologist Retha Newbold of the U.S. National Institute of Environmental Health Sciences, who found that BPA impairs fertility in female mice. “In animals, BPA can cause permanent effects after very short periods of exposure. It doesn’t have to remain in the body to have an effect.
So if humans can truly breakdown Bisphenol A faster than rodents, the amount of Bisphenol A detected in the bodies would have to “10 times what the EPA has deemed safe”. The younger the person, the greater the higher the level of Bisphenol A. Presumably, the greater the damage as the endocrine system plays a vital role in development.
But other studies since 1976 have shown that small doses (less than one part per billion) of estrogenlike chemicals, such as BPA, may be damaging. “In fetal mouse prostate you can stimulate receptors with estradiol at about two tenths of a part per trillion, and with BPA at a thousand times higher,” vom Saal says. “That’s still 10 times lower than what a six-year-old has.” In other words, children six years of age were found to have higher levels of BPA’s by-product glucuronide in their urine than did mice dosed with the chemical that later developed cancer and other health issues.
To avoid Bisphenol A, avoid canned foods and do not use products with recycling symbols #3,#6,#7(plastic baby bottles). Also adding heated liquids to polycarbonate bottles causes a spike in Bisphenol A leaching. How toxic does this make the household electric kettle ?
If canned goods or clear plastic bottles are a must, such containers should never be microwaved, used to store heated liquids or foods, or washed in hot water (either by hand or in much hotter dishwashers). “These are fantastic products and they work well … [but] based on my knowledge of the scientific data, there is reason for caution,” Belcher says. “I have made a decision for myself not to use them.”