A recent study has reportedly claimed that human exposure to bisphenol A (BPA) greatly exceeds the daily threshold set by the U.S. Environmental Protection Agency, which specifies the upper limit of BPA intake at 50 micrograms per kilogram of body weight. Julia Taylor, et al., “Similarity of Bisphenol A Pharmacokinetics in Rhesus Monkey and Mice: Relevance for Human Exposure,” Environmental Health Perspectives, September 2010. According to media sources, the study pegged human BPA exposure at more than eight times this threshold and speculated that exposure occurs “via multiple routes.”
The study also allegedly suggested that mice, monkeys and humans all process and excrete BPA at similar rates. The lead author reported that blood samples taken from both mice and rhesus monkeys contained “biologically active” amounts of BPA, raising questions about whether the liver effectively expels the substance or allows it to enter the bloodstream, where it could conceivably mimic estrogen and other hormones. “These data should make us reconsider some previously held hypotheses about BPA, such as how quickly it is cleared from the body and the differences in metabolism between species,” stated Linda Birnbaum, director of the National Institute of Environmental Health Sciences, in response to the findings. “The paper emphasizes the need to better understand all the potential sources of human exposure.”
Meanwhile, another researcher who contributed to the study has received a $100,000 prize for his work on BPA. The Heinz Awards recognized University of Missouri-Columbia Professor Frederick vom Saal for his investigations into the chemical’s purported link to abnormal cell development. “The new results clearly demonstrate that rodent data on the health effects of BPA are relevant to predictions regarding the health effects of human exposure to BPA,” vom Saal was quoted as saying. “Further evidence of human harm should not be required for regulatory action to reduce human exposure to BPA.” See University of Missouri- Columbia Press Release, September 20, 2010.