An anonymous reader quotes a report from Gizmodo: Plastic products that boast of being “BPA-free” aren’t necessarily any safer for us, suggests a new mouse study published Thursday in Current Biology. The chemicals used to replace BPA in these plastics can still leak out and affect the sperm and eggs of both male and female mice, it found. And these same effects could be happening in people. Bisphenol A, or BPA, is a chemical commonly used to create polycarbonate plastics and epoxy resins. These clear white plastics are themselves used in food and drink packaging, as well as consumer products and medical devices, while resins are used to coat metal products like canned foods. When these products degrade or are otherwise damaged (from being repeatedly heated in a microwave, for example), they can leach out BPA, exposing us to it. As a result, it’s estimated that 93 percent of Americans have some level of BPA in their system.
While working on another project, the authors began seeing some but not all of their control mice, both male and female, develop reproductive problems. Though the mice had kept in cages made of polysulfone, not polycarbonate, the researchers noticed a whitish residue in some of the cages, indicating they had been damaged and were leaching chemicals. When Patricia Hunt, a researcher at the Center for Reproductive Biology at Washington State University, and her team analyzed the chemical signature of the damaged cages, they found both BPA and BPS, a bisphenol that is widely replacing BPA. The cases were polysulfone plastic, which is partly made from BPA, but it’s advertised to be more heat and chemical resistant than polycarbonate and thus less likely to break down. Polysulfone isn’t thought to degrade into BPS, but Hunt’s team found that if certain chemical bonds in the plastic were broken in the right way, BPS could form. Following in the vein of their original experiments with BPA, Hunt’s team exposed more mice to low doses of BPS, and compared their reproductive health to mice exposed to BPA and mice raised in fresh new cages, presumably free of any BPA/BPS contamination. The BPS mice had more defects in their egg and sperm cells than did the control mice, but the level of damage was similar to that seen in mice they exposed to the same dose of BPA alone. “Though manufacturers have shied away from making explicit claims about BPA replacements being safer, Hunt noted, customers have certainly assumed that they are safer,” the report notes.
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