Chemical and Engineering News
March 4, 2011
Study finds that even BPA-free products leach potentially problematic compounds
From plastic bags to water bottles, most plastic products—even those that don’t contain the estrogen mimic bisphenol A—leach chemicals that trigger a bioassay for estrogenic activity, according to an analysis of more than 450 common plastic products (Environ. Health Perspect., DOI: 10.1289/ehp.1003220). The researchers who carried out the study, which only tested for estrogenic activity and did not identify any specific chemicals, suggest that this ubiquitous estrogenic activity could be eliminated by carefully reformulating plastics.
The study didn’t center on BPA, but instead focused on quantifying the biological effect of estrogenic activity, irrespective of the chemical causes, explains neurobiologist George D. Bittner of the University of Texas, Austin, who led the study. “Although BPA is the most notorious chemical with estrogenic activity used in plastics, it is not the only one, nor does it have the highest biological effect,” Bittner says.
The research was carried out by a team including researchers at CertiChem and PlastiPure, two contract firms founded by Bittner. CertiChem uses its estrogenic activity assays to test plastics, foods, chemicals, and packaging for clients. PlastiPure is a technology company that works with clients to design plastic formulations so that products can be certified to be free of estrogenic activity. The study was funded in part by the National Institute of Environmental Health Sciences, which publishes Environmental Health Perspectives.
The scientists extracted small pieces of plastic with saline or with ethanol, then added MCF-7 human breast cancer cells to samples of the extracts. After an incubation period, the researchers used ultraviolet spectroscopy to quantify the amount of DNA produced by the cells, which proliferate in response to estrogenic chemicals.
Bittner’s team found that about 70% of the plastic items tested positive for estrogenic activity. But when the researchers stressed the materials under “real world” conditions of simulated sunlight, microwaving, and dishwashing, about 95% of the products tested positive, including products labeled as BPA-free.