On December 4, 2014 the peer-reviewed scientific journal Environmental Health published a new study assessing the release of chemicals with estrogenic activity (EA) from thermoplastic resins. Polycarbonate (PC) resins based on bisphenol A (BPA), which exhibits EA, are nowadays commonly replaced to avoid the potentially harmful health effects of BPA exposure. Instead BPA-free thermoplastic resins are used to manufacture reusable hard and clear products including baby bottles and food containers. Bittner and colleagues used two in vitro cancer cell line assays to quantify the EA of chemicals that leached into ethanol or water/saline extracts of 14 BPA-free thermoplastic resins. The investigated resins were either unstressed or stressed by microwaving, autoclaving or exposure to ultraviolet radiation (UV) to mimic normal usage of plastic products in our daily lives. The scientists report that four tested resins leached chemicals with EA, including one polystyrene (PS), and three TritanTM resins, the latter labeled as EA-free. Especially UV radiation exposure resulted in increased release of EA from TritanTM resins. The additive triphenyl-phosphate (TPP), one of the ingredients of TritanTM, exhibited EA in both in vitro assays. However, the remaining ten glycol-modified polyethylene terephthalate (PETG), cyclic olefin polymer (COP) or copolymer (COC) thermoplastic resins did not release chemicals with detectable EA levels. Therefore, the current study shows that it is possible to manufacture PC-replacement plastic products from EA-free resins, given that EA-free additives are chosen. The first author of the study, George Bittner, has been previously involved in a law suit with Eastman Chemical concerning claims made about TritanTM manufactured by the company (previously reported on by the FPF).
Bittner, G.D. et al. (2014). “Chemicals having estrogenic activity can be released from some bisphenol a-free, hard and clear, thermoplastic resins.” Environmental Health (published online December 4, 2014)