Transdermal BPA Exposure Confirmed

A pair of studies provides evidence that skin absorption is a key way by which humans are exposed to bisphenol A (BPA), an endocrine-disrupting chemical that is under scrutiny for potentially being harmful to people. BPA is used as a plasticizer that is bound in polymers for making plastic bottles and food can liners, from which nanograms of the chemical leach out. BPA is also used as a color developer that is coated as a free monomer in milligram quantities on thermal-imaging paper used to print credit-card and cash-register receipts. Daniel Zalko of the French National Institute for Agricultural Research, in Paris, led a team that measured the diffusion of ¹⁴C-labeled BPA through samples of pig skin and human skin. A significant amount of BPA diffused through both types of tissue and was metabolized to glucuronide and sulfate derivatives (Chemosphere, DOI: 10.1016/j.chemo sphere.2010.09.058). Separately, Harvard University’s Joe M. Braun and coworkers monitored the diets and analyzed BPA in urine samples of 389 pregnant women. Cashiers had the highest BPA concentrations in their urine; teachers and industrial workers had significantly lower concentrations (Environ. Health Perspect., DOI: 10.1289/ehp.1002366). The studies help confirm speculation that BPA can be absorbed through the skin and that people who constantly handle receipts are at risk for higher exposure. Aware of the BPA-receipt connection, many retailers are in the process of switching to BPA-free paper.