There's a new reason other than fear of germs to wash hands after handling paper money: It contains traces of bisphenol A, the estrogen-like chemical Health Canada has just declared toxic.
The discovery was made by a pair of U.S. environmental advocacy groups, which tested 22 U.S. dollar bills and detected BPA on 21 of them.
The only bill without any was relatively new, leading the groups to speculate that money is being contaminated in purses and wallets by BPA rubbing onto it from cash-register receipts, which are frequently coated with the chemical.
To test this theory, the groups also checked receipts and found that half contained BPA, sometimes in large amounts. "Given what we know, the likely source [of BPA on the bills] is the receipts," says Erika Schreder, staff scientist at Seattle-based Washington Toxics Coalition, which together with the Safer Chemicals, Healthy Families Coalition, is issuing a report Wednesday on the findings.
BPA on receipt paper is attracting new interest as a possible source of exposure to the chemical, which scientists consider a possible health hazard because it is able to mimic the body's naturally occurring estrogen.
Up until now, government health authorities have assumed that nearly all the BPA circulating in people's bodies has come from residues inadvertently ingested by eating canned food or drinking from polycarbonate plastic bottles. Nearly all cans contain a thin epoxy liner that's partly made from the chemical, and traces can leach off plastic into beverages.
But the groups found the chemical easily got onto people's hands when they touched receipts or crumpled them up. This opens up the possibility that it can be absorbed through the skin or ingested by touching food or having hand-to-mouth contact through habits like chewing fingernails.
BPA is added to the thermal paper used in many cash-register and ATM receipts, and is easy to identify because of its distinctive light sheen.
Health authorities play down the worries over paper containing bisphenol A.
"Health Canada does not consider that this use would be a significant source of exposure for the general population (non-occupational)," the federal agency said in a written response to a request for comment. Still, it didn't address the possible elevated risk for retail workers who have above-average contact with receipts.
The agency "continues to monitor the scientific literature on BPA, including studies related to thermal paper as a potential source of exposure, and will take further action to protect the health of Canadians, if required," it said.
To date, Health Canada has banned plastic BPA-containing baby bottles and wants canning companies to investigate alternative liners.
The report by the two environmental groups cited estimates that cashiers would have doses at the high end of what people would get from eating a lot of canned food, and said even typical shoppers handling five receipts a day would have noticeable amounts.
Ms. Schreder suggests simple steps to minimize exposure to BPA from receipts. She has an envelope in her purse into which she places receipts so that she doesn't touch them when looking for change. She's also taken to refusing receipts when she can.
She also recommends washing hands after handling receipts and money and advises parents not to give receipts to children to play with.
Not all receipts contain BPA. One major manufacturer, Wisconsin-based Appleton Papers Inc., stopped using the chemical in 2006. Consumers haven't been able to tell whether receipts contain BPA, but Appleton recently said it would be adding tiny red fibres to its papers to distinguish them.