I often find myself gravitating towards products that have labels such as “organic”, “cruelty-free”, “free-range”, etc. stuck to their packaging. It’s comforting to know I am opting for a product that is beneficial to either my health, the environment, or both. That’s why when I’m faced with the option to purchase a water bottle that is BPA-free, versus one that is not, 10 times out of 10 I buy the former. For years now I believed this choice was protecting me from the harmful effects of bisphenol A, a chemical known to disrupt reproduction in mice. Much to my surprise, this belief was shattered by a recent article in Current Biology that revealed that the replacement bisphenols are potentially just as harmful.
BPA-free plastic water bottles – photo from Pixabay
Patricia Hunt, a biologist at Washington State University who first discovered the damaging effects of BPA 20 years ago, has uncovered data that mirrors those findings. This new study shows that BPS, a replacement bisphenol, is causing abnormalities in the eggs and sperm of mice. Essentially, BPA-free plastics could still be causing the same adverse effects in humans that led us to ban BPA so many years ago.
The findings were uncovered much in the same way as the BPA discovery decades ago. While conducting unrelated research, Hunt noticed changes in the data collected from her lab mice. Specifically, she found abnormalities in their eggs and low sperm counts. “Given our previous experience with BPA leaching from polycarbonate cages and water bottles,” states Hunt, “damaged materials were an obvious suspect”.
Upon analysis of the plastic cages that the mice were being kept in, Hunt and her team discovered that the inner surfaces to which the mice were being exposed had traces of BPS. The compound, which has replaced BPA in many household items, was being released from the plastic from everyday wear and tear. Notice the similarities between the two chemicals in the images below.
Chemical structure of BPA – photo from Wikimedia Commons
Chemical structure of BPS – photo from Wikimedia Commons
To further investigate the issue, Hunt designed experimental studies in which mice were exposed to several replacement bisphenols. The effects were observed by looking at the number of DNA points where chromosomes had been reshuffled, known as MLH1 foci. This data was telling as MLH1 foci is indicative of the degree of abnormality. Females who were found to have high numbers of MLH1 foci were producing abnormal eggs. On the other hand, males who had low numbers experienced an increase in cell death during sperm creation.
The thought that plastic, a material that we use daily, could be affecting our reproductive health is extremely concerning. The results from Hunt’s most recent studies are remarkably similar to those seen years ago with BPA and raise the question if bisphenols as a class should be eliminated. I hope an alternative replacement in plastics will soon be discovered so that we can still enjoy the diverse benefits of this material.
