In a contribution to Science 2.0 published on February 5, 2014, the executive director of the ACC’s Polycarbonate/Bisphenol A (BPA) Global Group, Steven Hentges, voices his view that public funding has been wasted on irrelevant BPA research (Hentges 2014). In particular, Hentges claims that 26 scientific studies funded by the National Institutes of Environmental Health Sciences (NIEHS) used BPA rodent exposures he calculated to be 10 000 times above current known human exposure levels (estimated at 0.1 μg/kg body weight /day). This, according to the author, is even more notable since all studies allegedly used low, environmentally relevant doses of BPA. In his view, the NIEHS studies are irrelevant for public health, since actual human BPA exposures are well below levels shown to cause harm in animal studies.
Food Packaging Forum perspective:
Varying estimates of human BPA exposure levels are available, and this is a current issue in the ongoing scientific debate. BPA exposure levels in some of the NIEHS rodent studies are around a factor 1 000 above a recent EFSA estimate for BPA exposure levels in the human population (previously reported by FPF). However, relating animal exposures to actual human exposure levels is not straight forward because of species differences in uptake, metabolism and excretion. For example, to reach blood levels in primates that correspond to human biomonitoring data, it was necessary to feed doses 8 times above the current tolerable daily intake (TDI) (Taylor et al. 2011), and around 4 000 times above the estimated human exposure level used in Hentges’ calculations. Therefore, of actual toxicological relevance are the levels of BPA measured in blood—and these measurements are currently under debate.
Steven Hentges (February 5, 2014). “Close Enough For NIEHS Work.” Science 2.0.
FPF article “EFSA publishes draft BPA opinion, part II”
Taylor, J. A., et al. (2011). “Similarity of Bisphenol A Pharmacokinetics in Rhesus Monkeys and Mice: Relevance for Human Exposure.” Environmental Health Perspectives 119(4): 422-430.