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Our BPA problem might be even worse than we think, according to a new study out Thursday. Researchers say they’ve devised a new test to measure levels of the common industrial chemical in our bodies—levels that might be far higher than tests endorsed by the U.S. government and others suggest they are.


BPA, or bisphenol A, is a ubiquitous ingredient in plastic products and coating resins produced throughout the world. In recent years, however, there’s been growing concern about its potential health effects on people and wildlife.

In many species, BPA mimics naturally produced hormones like estrogen. And it’s thought this mimicry can disturb the endocrine system that regulates everything from fertility to brain development. What’s worse, BPA can easily seep into the environment from the many products that contain it, making exposure practically impossible to avoid.


“These measurements, which have been done for many years, are likely really, really dramatically underestimating levels.”

BPA exposure seems especially bad for sea life and smaller animals. But there’s some evidence that BPA can have subtle effects on human health, too, especially in a developing fetus and young children. Studies have linked higher levels of exposure to a greater risk of health conditions like obesity and type 2 diabetes, as well as lower fertility in both men and women.

The U.S. has banned BPA from being used in products like baby bottles. Overall, though, the Food and Drug Administration has so far concluded that “BPA is safe at the current levels occurring in foods.” But the authors of this new study argue that the tests used by the FDA and other agencies to measure BPA exposure in people are drastically underestimating these levels.

BPA tends to be quickly broken down by the body into byproducts called metabolites. In their study, published Thursday in Lancet Diabetes & Endocrinology, the authors detailed the creation of a new test meant to more accurately detect these metabolites. Then they compared their new test to a commonly used one that indirectly measures BPA by converting the metabolites back to BPA via an enzyme.


“The assumption has always been that you can use this method as a surrogate for measuring metabolites,” co-author Patricia Hunt, a BPA expert at Washington State University, told Gizmodo by phone. “But the chemist on this paper, Roy Gerona, developed a direct method, which is far preferable.”


In experiments with both synthetic urine as well as samples taken from people, including pregnant women, the team consistently found higher and widely varying BPA levels using their test. In some samples, levels were 44 times higher than the average exposure in people estimated by government data. Also concerning was that in samples with higher levels of the metabolites, the disparity between the two methods became wider.

At this point, Hunt said, it’s not entirely clear why these earlier tests seem to be so far off the mark, especially for people with potentially high exposure. But the implications are troubling. If they’re even more inaccurate for people with higher levels of BPA, she noted, it’s possible our screening programs are missing these higher risk groups completely. That invisibility in turn could make it harder for scientists to uncover the potential health impacts of BPA.


“What that means is that these measurements, which have been done for many years, are likely really, really dramatically underestimating levels,” Hunt said.

While it’s unclear just how impactful these higher levels could be to our health, they do throw into question the FDA’s assurances that there’s little to worry about, according to Hunt. Because similar tests have also been used to study BPA replacements and other suspected endocrine-disturbing chemicals in people, we may be underestimating the scale of these exposures as well.


“This is the way science works. Our methodology gets better and better and better over time. So whether it’s X-rays vs cat scans or whatever, we get more sensitive ,” Hunt said. “But we might need to start questioning some of the decisions we’ve made. And it’s not that they were wrong decisions, but that they’ve been based on flawed assumptions.”

She added, “I think we really need to go back and do population screens using this new method and get more accurate readings—and ultimately that’ll also help us better understand the risks posed by this chemical by being able to differentiate between individuals who are highly exposed and those who are not.”


There still needs to be confirmation that the test developed by Hunt and her team is accurate itself, including from other independent research teams. But if they’re right, then there’s not much we can do right now about reducing our exposure to BPA.

“Consumers always ask, what can we do? And you know, the answer is, you know, it’s everywhere. It’s in our air, our soil, our water, so I can’t give you a magic answer—that all you have to do is this and you’ll be safe from it,” Hunt said. “But what it really means is that we need to go back and reevaluate the safety of this chemical.”