BISPHENOL A (BPA): A CLOSE LOOK

Mary Bachran and Theo Colborn

TEDX, Paonia, CO

We present the results of an EXCEL compilation of in vivo and in vitro studies that used bisphenol-A (BPA) at one part per million or less. We compiled the data in order to provide some organization to the rapidly increasing number of BPA studies that were published since 1997 when the first BPA low dose results were reported. Data were organized by endpoints which cover a wide range of parameters from the gene, to the molecular, cellular, tissue, organ, system, and whole animal level. We sorted endpoints by broad categories such as male reproductive system, female reproduction system, brain and behavior, and specific organ systems. The EXCEL spreadsheet provides the opportunity to break out the data in any grouping desired. The result of our gross summarization as of December 8, 2006 revealed that 84% of the studies found one or more significant effect at <1 ppm. Of these, 66% were in vivo studies, 28% were in vitro studies, and 6% were both in-vivo and in-vitro.  BPA not only exerted changes during gestation but also when administered during adulthood. There were more studies of the brain and behavior than in any other category and in this category the most consistent finding were alteration or elimination of sex-type behavior. Consistent with the finding in the 1930s that BPA was an estrogen, 100% of the studies examining the ovaries and 95% of the studies examining the breast revealed alterations. Non-mammalian studies also reaffirmed the estrogen-like role of BPA in the development of male systems across a number of species. The stage of development of any system or organ exposed to BPA determines the results. Low concentrations of BPA at any stage of life can result in alterations of structure and/or function of tissues, organs and systems.