Saturday, May 24, 2008

Bisphenol A (BPA)

Last night (Friday May 23) Bill Moyers aired a segment on the investigation of the dangers of BPA by journalists for the Milwaukee Journal Sentinel. It was sobering for many reasons. To begin with, here was a textbook case about why we still need newspaper journalism. The lead reporter, Susanne Rust, demonstrated both the persistence and expertise required for good journalism: she had studied endocrine disruptors in graduate school before becoming a journalist, and so was able to personally review hundreds of scientific articles to report firsthand on what they said. Needless to say, what she uncovered differed dramatically from what industry and government representatives were saying in response to the controversy. Second, the Journal Sentinel assigned no less than three reporters to this story, and gave them ample time—not hours or days but months—to thoroughly research the story. No television station would, these days, allow that much time for a story; it’s far cheaper to cover the latest murder or sex scandal.

Aside from this demonstration about the value of true journalism, the report was sobering in what it revealed about the possible dangers of Bisphenol A, and the criminal negligence of government agencies in downplaying those dangers. The internet is today full of reports about this, but one in particular provides ample reasons for anyone interested in his/her own health, and even more, the health of children or grandchildren, to be concerned. I am referring to a report by two scientists, F vom Saal (shown on the Moyers report) and C Hughes, titled “An Extensive New Literature Concerning Low-Dose Effects of Bisphenol A Shows the Need for a New Risk Assessment” (Environmental Health Perspectives, 2005). The article, which can be found on the website, (itself the name of a book by Colborn, Dumanosk, & Meyers), represents an overview of the scientific literature, and on that basis concludes that health standards for BPA “should be strengthened dramatically to protect public health.”

First, we should be clear about what BPA is. Though first synthesized in 1891, it was not used until 1931, when it was synthesized for use as an estrogen (only to be replaced by the infamous diethylstilbestrol (DES), because of the latter’s greater effect.) This initial intent is important because of the dangers BPA poses as an endocrine disruptor. In any case, chemists soon discovered BPA’s current use—its ability to polymerize, or form large chains, to become polycarbonate plastic. All well and good: polycarbonate plastic is hard and clear and widely useful. The fly in the ointment turned out to be that the bond linking BPA’s monomers to one another is not stable; it decays with time, releasing BPA into the materials it contacts, such as food or water. By now, many people have been alerted to the problem BPA poses in water bottles and food containers (it is used widely to line the inside of the metal cans containing foods of all kinds). But BPA is also used in making a host of other plastics, resins, fungicides, flame retardants, and even the plastic coating for children’s teeth to prevent cavities! It is ubiquitous in our plastic-drenched lives, and thereby in the environment (rivers and estuaries and our water supply) we have contaminated as well.

The government agency charged with protecting Americans from toxic dangers such as this, the EPA, has not conducted a new risk assessment for Bisphenol A in 15 years. It has essentially taken the word of the chemical industry that scientific studies (financed by the industry, of course) have shown that BPA is safe. vom Saal and Hughes, however, found a dramatically different story. First, they compared industry-funded studies with government-funded studies and found that of 115 relevant studies (11 by the chemical industry; 94 by government-funded research), “none of the 11 funded by industry reported adverse effects at low level, whereas 94 of 104 government-funded studies (from Japan, Europe, and the U.S.) found effects.” Now if you were the EPA, whom would you trust—the industry-funded studies? Or government-funded studies? Needless to say, EPA went with the industry studies.

vom Saal and Huges, however, clearly found the government-funded studies both more numerous and more convincing. They state: “the literature now provides overwhelming evidence that Bisphenol A alters cellular signaling, fetal development and adult physiology and reproduction in animals at doses far beneath the current ‘safe exposure’ level established by the U.S., 50 ppb (parts per billion).” In fact, vom Saal’s own first study reported “effects at 2 ppb, when male mice exposed in the womb (to BPA) grew up with enlarged prostates.” Not surprisingly, vom Saal’s study was severely criticized by chemical industry scientists, who said his results could not be duplicated. This must have been one reason for vom Saal and Hughes to conduct their review. Be that as it may, they found, first, that vom Saal’s results regarding the danger of even low levels of BPA had been duplicated numerous times in numerous labs. More important, more recent studies indicated that Bisphenol A, via its interaction with estrogen receptors within the cell nucleus, not only “alters expression of many genes dependent upon estrogen signaling,” but also “stimulates calcium influx into the cell,” a key process which also “alters the expression of genes involved in many different physiological processes, including brain growth, memory formation, the creation of fat cells, and reproductive development.” Indeed, in provoking these critical reactions, Bisphenol A has been found to be “more powerful” than diethylstilbestrol (DES)!

The conclusion reached by vom Saal and Hughes would seem to be a no-brainer: given its ability to alter such basic physiological functions, BPA may be involved in such diseases (all indicated by the studies reviewed) as: “obesity in adults, early puberty, reduced sperm count, breast cancer, impaired immune function, changes in brain chemistry, and changes in behavior—hyperactivity, increased aggressiveness, impaired learning, altered sexual behavior.” While all these indications come from animal studies since the relevant human research has not yet been done (indeed, it may be almost impossible to find control groups among humans who have NOT been exposed to BPA), it seems prudent to conclude that, given the widespread exposure of humans to BPA from so many sources, every individual should err on the side of caution. (Unless, that is, most of us have been so de-sensitized to chemical dangers by TV’s constant drug commercials running through their weirdly cheerful disclaimers—‘may cause headaches, stomach cramps, liver failure, heart attacks, blood clots, brain hemorrhaging, and sudden infant death syndrome’—that we’re too dumbed out to worry.)

The final conclusion of vom Saal and Hughes, however, indicates that even individual action, while prudent, will not be enough. This is because the ubiquity of BPA, most of it in unlabeled products, all leaching enormous quantities into the entire world’s water systems, means that we will all continue to be contaminated by Bisphenol A no matter what we do as individuals. As with global warming, it is governments—especially the U. S. government’s Environmental Protection Agency—which must act both nationally and globally to reduce the danger. And in order get them to do that, governments must no longer be allowed to dismiss the dangers of such a universally distributed substance. They must be deluged, starting with our own representatives, with demands for an outright ban on Bisphenol A. Whether they should subsequently be held accountable for the as yet uncalculated harm their negligence (or should we call it willful ignorance) has already caused is an open question.

Lawrence DiStasi

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