Receipts a large and little-known source of BPA: studies raise alarm about exposure to hormone mimic.
Two of the new studies also show that the BPA coating easily rubs off onto fingers. And one found evidence that BPA from receipts may penetrate skin.
The pollutant, which mimics the hormone estrogen and is used in the making of some plastics, has been tied to health risks from behavior problems in children to obesity and heart ailments. In animals, in utero exposures put moms and their offspring at risk for metabolic diseases.
Based on growing concern about possible risks from BPA exposure, especially in children, the federal government recently warned parents about where their families were most likely to encounter the chemical. Store receipt did not make the list although there have been hints for years that thermal receipt could be a rich source.
The BPA-receipts data offer "further evidence that bisphenol A, a dangerous chemical, has become all too prevalent in consumer products despite the fact that it is linked to harmful health effects in humans," says U.S. Sen. Dianne Feinstein of California. She notes that "industry is fighting against legislation that would restrict the use of BPA," including a bill that she coauthored.
Chemist John Warner learned about the chemistry of thermal- and pressure-sensitive papers while working for Polaroid years ago. Manufacturers lay a powdery coating containing BPA, a dye and a solvent onto one side of a piece of paper. When heat or pressure is applied, the coating's constituents merge to release the ink's color, he explains.
Warner largely forgot about the process until BPA hit the news, big time, about a decade ago. Wondering if thermal paper still used the chemical, he and his university students ran periodic assays--which invariably turned up receipts with substantial amounts.
On July 28, Warner and colleagues at the Warner Babcock Institute for Green Chemistry in Wilmington, Mass., formally published their data for the first time. Of 10 receipts recently collected in the Boston area, six contained 1.09 to 1.70 percent BPA by mass. Another two contained 0.30 to 0.83 percent BPA; the final pair had no measurable amounts. The findings appear online in Green Chemistry Letters and Reviews.
A Swiss study published online July 11 in Analytical and Bioanalytical Chemistry assayed 13 European sales receipts. Eleven contained BPA in quantities ranging from 0.8 to 1.7 percent of the paper's mass.
And that BPA rubbed off easily, notes study coauthor Koni Grob, an analytical chemist with the Official Food Control Authority of the Canton of Zurich. Just holding the receipt paper deposited substantial BPA onto dry fingers.
"The shocking thing" he says, "is what happened when I applied a bit of BPA onto my fingers with ethanol [alcohol]. After two hours it had disappeared. Totally." He believes the BPA probably penetrated deeply into the skin, perhaps as far as the bloodstream.
The Swiss team estimates that most people would not receive more than about 2.5 percent of the tolerable daily intake of BPA from handling a single receipt. But under a worst-case scenario--a pregnant cashier who wore hand cream that boosted BPA's permeability--someone might well sustain exposures that approached 50 micrograms per kilogram body weight, which is what European and U.S. regulatory agencies estimate as a tolerable intake.
"I think it's a scandal that you can have people touching thermal paper all day long," Grob says, since its surface coating could approach 10 percent BPA.
Frederick vom Saal of the University of Missouri in Columbia, who performed BPA assays for a recent study by the Washington, D.C.-based nonprofit Environmental Working Group, agrees.
"I won't touch receipts now," he says. The EWG study found BPA in 32 of 39 receipts collected from retailers in Washington, D.C., seven states and a city in Japan. Sixteen of the U.S. receipts contained substantial quantities of BPA, on average 1.9 percent by weight, the group reported July 27.
In follow-up studies, vom Saal has confirmed the same wet-versus-dry difference in transfer of BPA to fingers that was demonstrated by the Swiss group. Plus, vom Saal says, "we saw something they didn't report: that the longer you hold a thermal receipt, the greater BPA's transfer to your fingers."
Scientists at the National Institute of Environmental Health Sciences' National Toxicology Program have followed the emerging data on BPA in thermal paper. "We're exploring the feasibility of looking at how much [this paper] is contributing to exposures in people known to handle receipts frequently," says Kristina Thayer at NTP in Research Triangle Park, N.C. Such investigations might include testing to measure how well and how far BPA is absorbed through the skin and what conditions might influence that.
On July 15, the Environmental Protection Agency launched a BPA Alternatives in Thermal Paper Partnership. The program is recruiting paper companies, receipt-paper retailers, environmental groups, chemical companies and trade organizations to brainstorm ways to move "towards safer alternatives."
Appleton Papers of Appleton, Wis., switched to one of them--bisphenol sulfonate--in 2006, says company vice president Kent Willetts. EPA's new partnership program lists the sulfonate as a potentially acceptable substitute, he notes.
But, vom Saal observes, there's little way for a consumer to distinguish between receipts with and without BPA. They look identical.
"Frankly," Willetts says, "there hasn't been much awareness outside of the scientific and thermal-paper communities about this issue. So there was little outcry asking how to identify our paper."
The good news, Feinstein says, is that some paper companies have recognized the problem. "These companies should be commended, and it is my hope that consumers will demand that other companies voluntarily follow suit."
Here's your receipt In thermal paper receipts, a colorless dye is embedded in a solvent layer along with an activator--often BPA--that causes the dye to darken. Heating the solvent layer allows the reaction to occur.
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||STORY ONE|
|Date:||Aug 28, 2010|
|Next Article:||Back story: where to find BPA.|