Environment Recycling & Waste Synthetic Estrogen Contaminating Popular Plastic Packaging: Study By Kimberley Mok Writer McGill University Cornell University Kimberley Mok is a former architect who covered architecture and the arts for Treehugger starting in 2007. our editorial process Twitter Twitter Kimberley Mok Updated October 11, 2018 Migrated Image Share Twitter Pinterest Email Recycling & Waste Plastics Zero Waste Image: Plastic Bottles (2007) by photographic artist Chris Jordan Not only is plastic the ubiquitous bane of modern consumerist lifestyles, it's also increasingly seen as a potential health hazard. Fact: we now know that hard plastic polycarbonate water bottles, canned food and soda pop linings contain the "genderbender" chemical bisphenol A, which hormonally mimics estrogen. Now German researchers have found another unknown estrogenic chemical leaching from a widely-used plastic packaging material. The study, published online in Environmental Science and Pollution Research, is the first to discover that certain types of packaging are consistently leaching a hormonally active chemical into bottled water. Read on to find out which packaging to steer clear of.Scientists at Johann Wolfgang Goethe University in Frankfurt detected "estrogenic activity" in 78 percent of the water samples bottled by polyethylene terephthalate (PET) plastic — identifiable by the number "1" encased by the triangular arrows of the recycling symbol. Potential health risks?The exact health risks of PET are unknown, but we know that increased exposure to synthetic estrogens (like the case of BPA) are being linked to reduced sperm counts, increased rates of obesity, cancere and diabetes. In live animal sampling, the study also found that mud snails raised in the plastic mineral water bottles had increased embryo production. Though the scientists have yet to identify the substance(s) causing the estrogenic activity, they've ruled out bisphenol A (BPA) and phthalates for the moment, but they do know that PET does contain small amounts of antimony, another estrogenic compound. Not all PET equalHowever, not all the samples tested positive for estrogenic activity, suggesting that the chemical composition of PET differs from manufacturer to manufacturer. A bigger problemFor consumers however, the findings may have serious implications of "a bigger problem [because] if you go to the supermarket, everything is packed in plastic," says Martin Wagner, a PhD student in aquatic toxicology at the university. So now not only are polycarbonates implicated in a chemical genderbending phenomenon on a scale of which we can only guess at - apparently, we might have to ditch PET plastic packaging too (which is probably a good thing).