The most widely known of these chemicals are compounds called BPAs, or Bisphenol A, which have been widely criticized due to their estrogen-mimicking properties. Many plastic products are now marketed as BPA-free, though as a 2011 study notes, according to NPR, xenoestrogens in plastics are hardly limited to BPAs.
The study, which was co-authored by George Bittner, a professor of biology at the University of Texas, Austin, didn't limit itself to abstract testing: researchers actually utilized off-the-shelf plastic products, 450 of which were cut up and tested by CertiChem, a company founded by Bittner. When exposed to just saltwater or alcohol, an amazing 70% of those items released xenoestrogens. Bear in mind, that number reflects the tests conducted before real world conditions like sunlight, dishwashing and microwaving were tested. Under those more strenuous conditions, a full 95% of items released estrogenic compounds.
Just because consumer confusion is fun for the whole corporate family (or not), the team who tested the items actually focused on BPA-free items, and found that in some cases, BPA-free plastics actually released higher levels of xenoestrogens (which still sounds a lot like the monster in Alien, I know). This is largely due to the fact that in the rush to make their products BPA-free, many manufacturers have substituted other compounds, the effects of which are unknown.
While the study didn't focus on the health effects of xenoestrogens, it should be noted that estrogenic compounds do occur in our environment naturally. In fact, some plant species actually use archiestrogens as a form of self-defense against herbivores, controlling the male fertility of their predators (and you thought you were tough). Man-made estrogenics, however, have only been introduced into the environment over the course of the last 70 years, through industrial, agricultural and chemical companies and consumer usage of plastic products.
The social and environmental impacts of unrestricted waste-water contamination are far from fiction or questionable science. Just this past week, a toxic algal bloom in Lake Erie left half a million people in Toledo, Ohio without clean tapwater. While there were climate factors involved (think warm temperatures), the Microcystis type of algae feeds on phosphorus and nitrogen in order to grow. Phosphorus is commonly found in dish detergent and fertilizer, and is only partially regulated. Runoff sources such as these have contributed to the lake being loaded with phosphates, creating perfect growing conditions.
Sonya Lunder, a senior analyst at the Environmental Working Group, points out that fears about chemical contamination generally can't be solved by worried consumers, many of whom don't have reliable sources of information that are often scientifically dense and confusing. "Regulatory agencies need to study the effect of chemicals leaching out of plastic," she says, conceding that EPA programs so far have turned up few results.
So what can consumers do to avoid xenoestrogens? "We've long cautioned consumers to avoid extreme heat and cooling for plastics, to discard scratched and worn plastics," Lunder says. As the knowledge base builds around xenoestrogens, it seems that old adages and avoidance of plastic products, where possible, is still the best prescription.