Bisphenol-A (BPA), a possibly toxic chemical found in many plastic products, leeches from plastic when it comes in contact with hot liquid. A team led by a Scott Belcher, PhD, a University of Cincinnati professor, discovered that when some new and used polycarbonate drinking bottles were exposed to boiling water, BPA released 55 times quicker than before exposure.
BPA is an environmental estrogen found in dental sealants, food can liners, the liners of baby formula cans, CDs and DVDs, eyeglasses, and hundreds of household goods. Worries about hormone-mimicking BPA used in sports bottles led a major Canadian retailer to remove polycarbonate plastic containers from shelves in early December.
“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,” says Belcher, “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 is one of many man-made chemicals classified as endocrine disruptors, which alter the function of the endocrine system by mimicking the role of the body’s natural hormones. Researchers and environmentalists revealed BPA causes several types of cancer (breast and prostate) as well as developmental, neural, behavioral, and reproductive harm (miscarriages and other reproductive failures), and obesity and hyperactivity in animals.
“Inspired by questions from the climbing community, we went directly to tests based on how consumers use these plastic water bottles and showed that the only big difference in exposure levels revolved around liquid temperature: Bottles used for up to nine years released the same amount of BPA as new bottles. 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.”
Belcher’s team analyzed used bottles from a local climbing gym and purchased new bottles of the same brand from an outdoor retail supplier. All bottles were subjected to seven days of testing simulating normal usage during backpacking, mountaineering, and other outdoor adventure activities. Researchers found BPA released from all the bottles was the same in quantity and release speed into cool or temperate water; however, drastically higher levels were released when bottles were briefly exposed to boiling water. “Compared to the rate of release from the same bottle, the speed of release was 15 to 55 times faster,” explains Belcher.
Everyone agrees BPA disrupts the hormonal system; however, scientists differ widely on whether low doses are harmful. Belcher urges consumers to think about how cumulative environmental exposures might harm their health. “BPA is just one of many estrogen-like chemicals people are exposed to, and scientists are still trying to figure out how these endocrine disruptors—including natural phyto-estrogens from soy which are often considered healthy—collectively impact human health,” he says. “But a growing body of scientific evidence suggests it might be at the cost of your health.”
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