The Bisphenol-A Effect

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BPA Bottle

Bisphenol-A, more commonly known as BPA, is an industrial chemical found in plastic, receipt paper and dental sealants that mimics estrogen and disrupts the hormones of many species of animals, including humans. We accidentally ingest BPA when the chemical makes its way into our foods from polycarbonate plastic bottles or the epoxy resin coatings that line canned food. It has been estimated that the average adult ingests an estimated 1 microgram of BPA for every kilogram (2.2 pounds) of body weight.

BPA, which is used to make plastic since it is a popular hardening agent, has become synonymous with danger in household across the world since studies have found that this chemical shows a potential cancer risk, amongst other troublesome findings. Researchers at University of Alabama at Birmingham found that a chronic low-level exposure to a compound could cause women to overproduce a protein linked with breast cancer, a ten-year study of subjects with higher urine concentrations of BPA found that they were more likely to later develop heart disease.

What’s more, BPA is especially dangerous for infants and toddlers since they have more exposure to the chemical: A National Health and Nutrition Examination Survey by the Centers for Disease Control and Prevention found detectable levels of BPA in 93 percent of urine samples collected from more than 2,500 adults and children over 6. Babies get exposed to BPA from the polycarbonate bottles and formula from cans. Studies have found that exposure to BPA in the womb is associated with behavior and emotional problems in young girls, may increase the propensity to develop breast cancer, increases the risk of Down Syndrome, and in addition to affecting the heart, brain and nervous system, bisphenol A (BPA), could affect a mammal’s ability to reproduce by altering the structure of the uterus.

A new study, published this week in the journal Evolutionary Applications, has found that BPA isn’t just problematic for our health–the chemical agent is responsible for interspecies sex that could upend ecosystems. Similar to how BPA disrupts our hormones, it disrupts hormones of a wide range of animals. BPA is a common pollutant in nature, and thus manages to make its way into our waters. Lead researcher Jessica Ward, an ecologist at the University of Minnesota, said in a press release that chemicals from household products and pharmaceuticals often end up in rivers, and thus, BPA is present in the aquatic ecosystem in the US.

The study looked at how BPA affected two fish found in rivers and streams in the U.S.–the blacktail shiners and red shiners–and collected samples from Georgia. They kept the species separate and exposed them to BPA, and finally put the fish in the same tank. The idea was to keep an eye out for physiological or behavioral changes such as size, color, courtship displays or mate choice. What did they find? The authors wrote: “Our research shows how the presence of these manmade chemicals leads to a greater likelihood of hybridization between species.”

The authors of the study reveal the ecological problems with BPA-induced interbreeding of species:

“This can have severe ecological and evolutionary consequences, including the potential for the decline of our native species. This process poses long-term ecological consequences, especially in areas threatened by the introduction of invasive species. BPA and other hormone-mimicking chemicals can escalate the loss of native biodiversity by breaking down species barriers and promoting the invader. Our results contribute to a growing body of evidence demonstrating that the effects of human-mediated environmental alteration can extend well beyond individual-level reproductive success with significant evolutionary consequences for populations and species.”