Atmospheric Multiphase Oxidation of Bisphenol A and Its Alternatives: Transformations and Kinetics in Air

JIE YU, Yufeng Gong, Hui Peng, Jonathan Abbatt, John Liggio, University of Toronto

     Abstract Number: 97
     Working Group: Indoor Aerosols

Abstract
The industrial chemical bisphenol A is widely used in the production of polycarbonate and epoxy resins, flame retardants and many other plastic consumer products for decades. But it is also a well-known endocrine disruptor that is exposed to humans via multiple exposure pathways and has raised many health concerns. The use of bisphenol A is banned in baby products in the US, Canada and EU, and so a broad class of bisphenol A alternatives – structurally similar to BPA – has been developed and used in “BPA-free” products. Little research has been done on the safety of these alternatives, but some alternatives have shown indications of being endocrine disrupting. Given the ubiquitous presence of bisphenol A and its alternatives in ambient aerosol particles and dust samples, the potential to undergo heterogeneous oxidation with atmospheric oxidants is high. However, prior studies only looked at the fates of bisphenols in surface water during wastewater treatment. For other environmental compartments, their transformation pathways with the presence of various oxidants are largely unknown. Uncertainties remain in the loss kinetics of the parent chemicals, the transformation pathway of the oxidized products, and the associated health impacts of the products.

This is the first study to assess these uncertainties by performing both gas-surface and gas-aerosol phase oxidation of Bisphenol A and some alternatives under atmospherically-relevant oxidation conditions, with a focus on the kinetics and transformation mechanisms. Laboratory heterogeneous oxidation was conducted in oxidation flow reactors (OFR) with important atmospheric oxidants O3 and OH. Both thin films of the reactants and suspended particles were used with, respectively, offline analysis by LC-ESI-MS and online analysis by an extractive electrospray ionization MS (EESI-MS). The major transformation pathways are proposed for oxidation conditions. These preliminary results will be valuable in evaluation of the toxicity and human exposure level of these oxidation products.