RESEARCH TRIANGLE PARK — While you are standing in line, impatiently tapping your foot, that cashier painstakingly installing a fresh roll of paper in the cash register may be putting his or her health at risk.
Researchers at the National Institute of Environmental Health Sciences are recruiting cashiers willing to have blood and urine samples taken to be tested for a potentially toxic chemical - bisphenol A, or BPA for short - that is used to manufacture the slick receipt paper many cashiers handle on a daily basis.
"Receipts have very, very high levels of BPA," said John Bucher, associate director of the National Toxicology Program at the NIEHS.
BPA is a common ingredient in durable plastics, like those used to make hard plastic water bottles and to line food cans. Some types of thermal paper used in cash registers are coated with BPA, and the chemical easily rubs off onto your fingers when you touch them.
In recent years, scientists have become concerned that BPA could cause developmental problems in children and reproductive problems in adults, but the evidence is conflicting.
"The science surrounding BPA is complicated and controversial," Bucher acknowledged.
From mice to people
Different studies have found different levels of risk. Most studies use laboratory animals such as mice to test BPA's toxicity, and researchers can't always be sure that BPA will affect humans and mice in the same way.
In their new study, the NIEHS team will measure levels of BPA in the blood and urine of volunteer cashiers, said Stavros Garantziotis, who is directing the research.
Testing BPA levels before and after a cashier's shift will show how much BPA was absorbed into a cashier's body while he or she was working.
"I haven't noticed any unusual effects," said Jordan Denton, who works the register at Port City Java in downtown Raleigh. He then joked, though, that he has developed superpowers since he started handling receiptsevery day. "That's not that odd, is it?"
The staff at the Port City Java trade off working the cash register and say they would have never thought to worry about chemical exposure on the job.
"Exposure to some of the customers I encounter, yeah, but never to chemicals," quipped owner and manager Tanyen Kerr.
Earlier study too small
But it's not just idle speculation that suggests cashiers could be exposed to more BPA than the general population.
In a 2010 study, researchers in Cincinnati saw that cashiers had significantly higher levels of BPA in their urine than the study's other participants. There is no evidence that handling receipts poses a risk to consumers, or that these high levels are dangerous for cashiers.
The 2010 results were based on 17 cashiers, not enough to be convincing without more research. Garantziotis said he hopes to get 100 volunteers for the NIEHS study.
In addition to assessing the danger to cashiers from receipts, the NIEHS researchers hope their study will shed light on how well BPA is absorbed through the skin.
Scientists know that BPA can enter the bloodstream when people eat contaminated food and drink. They aren't sure if that can happen simply from touching items like receipts coated with BPA. The team also wants to investigate whether anything increases BPA's absorption, such as using hand cream.
Alternative paper on tap
In the midst of the BPA controversy, Garant ziotis noted, the industry that produces register paper has been responsive. There are alternatives on the market already, he said. One of the most common of these uses a BPA relative called bisphenol S.
But nobody knows very much about these alternatives either, he said.
"There are alternatives on the market, and although they are now being touted as innocuous, we do want to know ... what happens with those, so that we can essentially be ahead of the game," Garantziotis said.
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