The Cardno ChemRisk View
A group of researchers from Cardno ChemRisk will attend the 2015 Society of Toxicology's Annual Meeting in San Diego, California from March 22-26. At SOT, we will present recent research during posters and presentations.
The Red Herring of BPA Featured
Bisphenol A (BPA) is a monomer used to manufacture polycarbonate, a type of plastic used to make food containers and drinking bottles, as well as the resin lining in food cans and bottle tops. With an established reputation as a xenoestrogen (i.e., a “foreign” estrogen), BPA has been viewed as a reproductive and developmental toxicant by several scientific and public-interest organizations (e.g., the Environmental Working Group, Natural Resources Defense Council, and Plastic Pollution Coalition) because of research reporting sexual dimorphism, preneoplastic lesions in the prostate and mammary glands, altered prostate gland and urinary tract development, and early onset of puberty in laboratory animals at low doses (NTP, 2008, 2010). Because of studies such as these, coupled with the fact that BPA was detected in 93% of a sampled U.S. population, concern has been growing regarding the safety of this compound (Calafat et al., 2008).
Recent research indicates that previous studies showing that low dose BPA exposures caused reproductive and developmental effects in animals were, in fact, not low dose exposures comparable to those experienced by the human population. Teeguarden and Hanson-Drury, for example, found that “the ‘low-dose’ moniker describes exposures covering 8–12 orders of magnitude, the majority (91–99% of exposures) being greater than the upper bound of human exposure in the general infant, child and adult U.S. Population” (Teeguarden and Hanson-Drury, 2013, p. 935). New findings also demonstrate that BPA is metabolized and cleared from the human body considerably faster than in rodents, which were largely utilized for toxicity testing; this difference explains why effects are seen in test species, but also suggests that findings in animals bear little relevance for humans. In addition, blood levels resulting from typical human exposures have been determined to be too low to elicit any adverse effects (Teeguarden et al., 2013). In turn, the FDA maintains that “BPA is safe at the current levels occurring in foods,” and, although federal bans on BPA in baby bottles and infant formula packaging have recently been instituted, they were founded on the basis of “abandonment” (the prohibition of a chemical that has already been phased out of use by industry), rather than on evidence that dietary consumption of BPA may cause human health effects (U.S. FDA, 2013). Given the discrepancies between the scientifically established safety of BPA and its current public perception, it is important to conduct research of human relevance to ensure the safety of manufactured products and to avoid misinformation.