Apparently, you can’t rest easy with your BPA-free plastic bottles and containers. As indicated by a study published last week, commercial plastic packaging in the form of bottles, containers, and wraps release chemicals with estrogenic activity. Estrogen molecules are female hormones that can disrupt sex development in animals if not regulated in the environment.
Bisphenol-A (BPA) is one of the chemicals used in plastics that mimics the effects of estrogen molecules. Manufacturers have removed BPA from their products after concerns grew over its effects. Countries like Canada have listed it as a toxic compound.
The study, published inÂ Environmental Health Perspectives,Â didn’t focus on BPA but instead measured total estrogenic activity, irrespective of the chemical causes, in plastics. Â The plastics analysis was led by neurologistÂ Dr. George Bittner at the University of Texas at Austin and colleagues. Some of the team members came fromÂ CertiChem andÂ PlastiPure, two companies founded by Bittner. The National Institute of Environmental Health Sciences, which publishesÂ Environmental Health Perspectives, and the National Science Foundation partly funded the work.
The researchers bought more than 450 plastic items from Walmart, Whole Foods, and other stores, choosing products that came into contact with food, such as baby bottles and deli packaging.Â The researchers soaked pieces of the products in saltwater or alcohol, then added samples of the extracts to MCF-7 human breast cancer cells. Next, the researchers measured the amount of DNA produced by the cells, which rapidly multiply when exposed to estrogenic molecules.
The plastics analysis revealed that more than 70% of the products released chemicals that mimicked estrogen. The researchers repeated the experiment after subjecting the plastics to real-world conditions: simulated sunlight, dishwashing, and microwaving. Under those conditions, about 95% of the products tested positive for estogenic activity, including most of the products labeled as BPA-free. Because of the nature of the experiments, the researchers weren’t able to identify the molecules being released by the plastics.
Early reaction to the study was mixed. Some scientists wondered about the test’s reliability. Others noted that wine and many vegetables also can act like estrogen. And a few observed that Bittner has a financial interest in the testing lab and in a company involved in making plastic products that don’t release estrogenic chemicals.
On the other hand, groups that have warned about the potential dangers of BPA in the past seemed to welcome the new research.
For now, manufacturers who have gone BPA-free have switched from polycarbonates and epoxy resins to different base polymer systems, notably glycol-modified polyethylene terephthalate and clarified polypropylene, Bittner notes. “As our data show, the switch to new materials has not ameliorated the estrogenic activity,” he says. But it’s encouraging that some plastics don’t have estrogenic activity, Bittner adds, and he believes that chemists have the capability to broadly design affordable products with properties comparable to today’s plastics that don’t release detectable estrogenic chemicals
Source: “Most Plastics Release Estrogenic Chemicals,” Chemical and Engineering News, 03/04/2011
Source: “Most Plastic Products Release Estrogenic Chemicals: A Potential Health Problem That Can Be Solved,” Environmental Health Perspectives, 03/02/2011
Source: “Study: Most Plastics Leach Hormone-Like Chemicals,” NPR, 03/02/2011
Source: “Most Plastics Leak Harmful Chemicals Into Food, Study Finds,”Â LA Weekly‘sÂ Squid Ink blog, 03/03/2011
Image by nerissa’s ring, used under its Creative Commons license.
Rajendrani "Raj" Mukhopadhyay is a science writer and editor who contributes news stories and feature articles on scientific advances to a variety of magazines. Raj holds Ph.D. in biophysics from Johns Hopkins University.