JUST how dangerous is bisphenol A, a chemical found in plastic containers and drinking bottles? Six months ago, the European Food Safety Authority (EFSA) concluded that, despite previous links to breast and prostate cancer and a range of developmental problems, human exposure to bisphenol A (BPA) was well within safety limits and posed no immediate health risks.
Now, a team of researchers has challenged this idea. It reviewed the same set of data and concluded that BPA is present in human tissues at concentrations 10 times as high as those considered safe by government agencies, and that the chemical can have damaging impacts on health at far lower concentrations than previously thought.
As 91av went to press, an expert panel convened by the US National Toxicology Program Center for the Evaluation of Risks to Human Reproduction was meeting in Alexandria, Virginia, to discuss the findings and decide whether to recommend a change in BPA policy.
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Precisely because human exposure to BPA is so widespread, the US Department of Health and other US government agencies asked Frederick vom Saal at the University of Missouri-Columbia and 37 other international researchers to review more than 700 scientific papers on BPA. The team’s conclusions suggest that BPA concentrations in human tissue are consistent with an exposure level of 0.5 milligrams per kilogram of body weight per day – 10 times the safe reference dose set by the US Environmental Protection Agency (Reproductive Toxicology, ).
“The team’s conclusions suggest that bisphenol A concentrations in human tissue are 10 times the safe reference dose”
The EFSA finding is the result of poor science, says vom Saal. “To draw the conclusion [that BPA exposure is within safe limits] you have to ignore the publications showing that there is extensive and continuous exposure of humans to BPA. It is unacceptable to pretend that this has not been demonstrated.”
Vom Saal also believes that BPA poses a health risk at concentrations far below those humans are exposed to, a conclusion again at odds with EFSA’s findings. A key reason for the discrepancy may be that EFSA dismissed much of the animal data relating to BPA’s toxicity because humans metabolise BPA much more quickly than animals. However, vom Saal says the animal data is relevant. “At the cellular level there is essentially no difference between the way mouse cells respond to BPA and humans do,” he says. And because BPA affects the hormonal system, it can have an effect at “staggeringly small concentrations”, he adds.
Vom Saal now plans to examine the scientific rationale behind the EFSA report to identify whether it could have been biased by commercial interests – an allegation EFSA strongly denies. “We trust both our scientists and the procedures in place to ensure the impartiality of our advice,” an EFSA spokeswoman said.
