By Steve Milloy
November 4, 2010, GreenHellBlog.com
Radical environmentalists and unscrupulous profiteers have put together a perpetual junk science machine in hopes of driving the chemical bisphenol A (BPA) to extinction. That machine includes a gullible/sympathetic media that hopes to get away with telling the public only part of the story. Consider a Nov. 2 report by Science News’ Janet Raloff, “Skin is no barrier to BPA study shows; Finding suggests store receipts could be significant source of exposures.”
Raloff starts her story by quoting the University of Missouri-Columbia’s Frederick vom Saal (more on him later), who says that
“The new study [by Daniel Zalko et al. and published in Chemosphere] is now unequivocal in showing that yes, BPA can go through human skin.”
While no one disputes that some BPA can be absorbed through the skin, the question is how much and is this harmful?
As Zalko admits in his study, BPA is metabolized to highly water soluble metabolites that are known to be estrogen inactive. This downplayed fact is, of course, devastating to the underlying scare, which relies on the hypothesis that absorbed BPA acts like an estrogen.
To get around this problem, Raloff obliquely acknowledges it by stating,
“Though such transformations are often assumed to render a chemical nontoxic…”
She then offers a naked claim by Zalko in contradiction:
“’that would be a false assumption,’ Zalko says, ‘because any compound that has been conjugated can be deconjugated’.”
But while Zalko claims that these metabolites can be converted back into BPA in the body, this is pure speculation (wishful thinking?) on his part as there is no data to support the claim.
Raloff then tells us that,
The role of metabolites in BPA’s potential toxicity is complicated, vom Saal says, because the body can — and regularly does — conjugate and deconjugate compounds. “It’s well known,” for instance, “that the body is full of desulfating enzymes, which play a role regulating estrogen levels during pregnancy.”
There is no doubt that the body is full of many chemicals that have a variety of roles — but there remains no evidence that the body converts any non-estrogenic BPA metabolites back into BPA.
Raloff’s article then goes on to discuss another earlier Zalko study involving application of BPA to the ears of dead pigs. Zalko reports that after three days, more than half of the applied BPA diffused through the skins of the pig ears.
But who cares about how much BPA can be absorbed by the ears of dead pigs? We have data from real human beings. As pointed out on this blog earlier:
A June 2010 study published in the journal Annals of Bioanalysis and Chemistry by Swiss food regulators reported that a person repeatedly touching thermal printer paper for 10 hours/day, such as at a cash register, would absorb 42 times less BPA than permitted by current safety regulations, which already have a very significant margin of safety. No workers or consumers would normally be exposed to even such infinitesimal amounts.
A February 2010 study from the University of Zurich’s Centre for Xenobiotic Risk Research reported that, “Dermal absorption (that is, absorption through the skin), is therefore at most a secondary absorption route for bisphenol A. The primary absorption route is still dietary intake. For this route, daily total amounts of bisphenol A around 10,000 times higher are considered harmless for adults.”
Raloff relies heavily on vom Saal to validate Zalko’s claims and insinuations. But she omits mention of two salient facts about vom Saal:
- He is a long-time and reality-free advocate against BPA; and
- His scientific claims against BPA have not been replicated by independent scientists.
Raloff concludes her article by pointing out that Appleton Papers is poised to rush to market BPA-free receipt paper for the upcoming holiday season. No doubt Raloff’s Science News hatchet-job will accompany Appleton’s marketing pitches — a perfect accompaniment as it contains not a single skeptical or dissenting voice.
BPA may be targeted for extinction but here’s why the rest of us ought not let that happen.
BPA is the test case for the bogus theory of endocrine disrupters. If the radical greens get away with destroying BPA’s reputation based on that never-validated hypothesis, they will proceed to use that scam against a host of other chemicals. The battle for BPA is not really about BPA. It’s about whether we will use science or circuses to determine chemical safety.