Study: Human exposure to BPA ‘grossly underestimated’
By GAYATHRI VAIDYANATHAN of Greenwire
September 20, 2010 Americans are likely to be exposed at higher levels than previously thought to bisphenol A, a compound that mimics hormones important to human development and is found in more than 90 percent of people in the United States, according to new research. U.S. EPA says it is OK for humans to take in up to 50 micrograms of BPA per kilogram of body weight each day. The new study, published in the journal Environmental Health Perspectives, suggests that we are exposed to at least eight times that amount every day. “Our data raise grave concern that regulatory agencies have grossly underestimated current human exposure levels,” states the study. The study also gives the first experimental support that some BPA is likely cleared at similar rates in mice, monkeys and humans, making it possible to extrapolate health studies in mice to humans. … Hormones are essential during development and can determine, among other things, a child’s gender. BPA, since it mimics estrogen, is an “endocrine disrupter,” according to Thomas Zoeller, a biology professor at the University of Massachusetts, Amherst. And amazingly, BPA has the ability to bind to not one, but three receptors — the estrogen, the male hormone and the thyroid hormone receptors, Zoeller said. … Zoeller at the University of Massachusetts, Amherst, said that this study provides some evidence that the liver allows some BPA to get into blood and that our exposure to the chemical is greater than previously thought. “The body evolved to handle stuff that gets into our system — the liver is designed to detoxify,” he said. “There are a range of molecules that are natural, and some are incredible toxins. But when we start to make molecules that are not known to nature, we need to think a little more carefully about how they are going to interact with biological systems.” …
