Depressing news for those of us who've gone out of our way to purchase BPA-free containers. In 2010 BPA was shown to be
possibly harmful to fetuses, babies and children,
which led to a wave of BPA-free merchandise that hit the market. But it turns out the replacement for BPA, BPS, is now looking to be likely equally harmful as BPA itself.
BPA is the starting material for making polycarbonate plastics. Any leftover BPA that is not consumed in the reaction used to make a plastic container can leach into its contents. From there it can enter the body. BPS was a favored replacement because it was thought to be more resistant to leaching. If people consumed less of the chemical, the idea went, it would not cause any or only minimal harm.
Yet BPS is getting out. Nearly 81 percent of Americans have detectable levels of BPS in their urine. And once it enters the body it can affect cells in ways that parallel BPA. A 2013 study by Cheryl Watson at The University of Texas Medical Branch at Galveston found that even picomolar concentrations (less than one part per trillion) of BPS can disrupt a cell’s normal functioning, which could potentially lead to metabolic disorders such as diabetes and obesity, asthma, birth defects or even cancer. “[Manufacturers] put ‘BPA-free’ on the label, which is true. The thing they neglected to tell you is that what they’ve substituted for BPA has not been tested for the same kinds of problems that BPA has been shown to cause. That’s a little bit sneaky,” Watson says.
Scientists at the University of Calgary studied the effects of BPS on zebra fish and found alarming results about the effects of these chemicals on brain development.
When the fish were dosed with BPS in similar concentrations to that found in a nearby river, neuronal growth exploded, rising 170 percent for fish exposed to BPA and a whopping 240 percent for those exposed to BPS. As the fish aged they began zipping around their tank much faster and more erratically than the unexposed fish. The researchers concluded that increased neural growth likely lead to hyperactivity. “Part of the problem with endocrine disruptors is they usually have a U-shaped dose response profile,” Kurrasch says. “At very low doses they have activity and then as you increase the dose it drops in activity. Then at higher doses it has activity again.” She found a very low dose—1,000-fold lower than the daily recommended amount for humans—can affect neural growth in zebra fish.
In a separate study, both BPA and BPS were also proven to cause heart arrhythmias in lab rats.
As with so many things, the problem comes down to a lack of regulation.
Currently, no federal agency tests the toxicity of new materials before they are allowed on the market. “We’re paying a premium for a ‘safer’ product that isn’t even safer,” Kurrasch says. There are many types of bisphenols out there, so part of the public’s responsibility “is making sure [manufacturers] don’t just go from BPA to BPS to BPF or whatever the next one is.”
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