Researcher Raised BPA Alarm in 1993May 12, 2008 | Parker Waichman LLP
Bisphenol A—commonly known as BPA—is a ubiquitous chemical that has been under debate and in the news in recent weeks. BPA is a chemical compound that mimics estrogen and is found in polycarbonate plastics and epoxy resin. On April 18, Canada announced it would ban baby bottles containing BPA starting mid-June, an action that made Canada the first country in the world to set exposure limits on the chemical. Also, the US National Toxicology Program—an arm of the National Institutes of Health, just concluded that there is “some concern” that fetuses, infants, and children may be harmed by the amounts of BPA that leach out of many brands of baby bottles, hard-plastic water bottles, and food cans lined with epoxy resin.
David Feldman, MD, emeritus professor of endocrinology at Stanford Univesity, and his team were the first researchers to identify and warn about possible effects of low levels of BPA on humans. Feldman says that he and his team discovered the health issues with BPA basically on accident. “We were not looking for it. We study receptors for steroid hormones like estrogen and were looking for both receptors and hormones when we found what looked like an estrogenic molecule in the culture medium.” It turns out that BPA was leaching out of the polycarbonate plastic used to contain the medium, leading the researchers to link its estrogenic properties to people who were eating or drinking out of containers made of polycarbonate.
Feldman and his team sent samples to the company that made the polycarbonate flasks to warn them of the problem, but they couldn’t find BPA because Feldman’s biological tests were more sensitive than the company’s, which were meant to identify levels of more than 25 to 50 parts per billion. Anything under that amount was considered safe. Feldman’s team was picking up levels and seeing estrogenic biological effects, at five to 10 parts per billion. Feldman and his team published their findings in 1993
“Although we published our findings in 1993, it was unclear for a long time how much of the bisphenol A was absorbed by humans, how fast it accumulated, and even whether or not it was damaging to human health” says Feldman. “One thing we do know is that, in the 2003-04 National Health and Nutrition Survey conducted by the Centers for Disease Control, 93 percent of about 2,500 people ages six and above had detectable levels of bisphenol A in their urine. So almost everyone is exposed,” added Feldman. Another study places the figure at 95 percent.
Studies confirm BPA is chemically similar to diethylstilbestrol, a synthetic estrogen linked to the development of vaginal cancer in the daughters of women who took the drug in the 1950s and 1960s to prevent miscarriage. BPA has been in commercial use since the 1950s and is found in a wide variety of everyday items including water bottles, food and drink packaging, food can linings, dental sealants, CDs and DVDs, eyeglasses, and automobiles.