The next plastic water bottle you buy won’t have bisphenol A in it, but the receipt might. A series of recent studies have found high levels of the toxin in an unlikely but ubiquitous place: cash register receipts.
One study found that touching a receipt for five seconds with a single fingertip wiped off up to 23 micrograms of bisphenol A (BPA). The chemical could then find its way onto food and be ingested. The amount wiped off increases tenfold when all fingers contact the paper and “by an order of magnitude,’ scientists say, when the paper is crumpled in one’s palm.
The full article appears in the September issue of Analytical and Bioanalytical Chemistry, a German scientific journal.
BPA has been in the news since 2007 when some retailers pulled hard plastic bottles from their shelves. There was concern that trace amounts of the chemical were seeping into the water. A year later the federal government announced that Canada would be the first country to ban BPA from plastic food containers.
All calculations that deal with BPA levels are intangibly small, measured in micrograms and parts-per-billion. Health Canada says it is dangerous to consume more than 25 micrograms per kilogram of body mass per day. But levels even lower than that may be too much. A 2009 research group found “long-term adverse reproductive and carcinogenic effects’ in mice given only one microgram per kilogram of body mass.
There is much discussion on the effect of BPA on humans, but no conclusive testing has been done to support or rebut detrimental claims. One certainty is that there is a lot of BPA in cash receipts.
Receipts, and theatre and concert tickets are all printed on thermal paper. The dye is already part of the paper, which makes for an inexpensive and reliable printing process. When heat is applied, a solvent in the paper melts and allows dye to mix with BPA and darken, which produces the desired text.
Scientists in Boston have analysed the chemicals in thermal paper. In July, researchers from the Warner Babcock Institute took receipts from 10 businesses and extracted all the BPA. They found between 3,000 and 19,000 micrograms in the 30-centimetre strips.
That much BPA is more than 12 times Health Canada’s limit for a 60-kilogram person, although it’s unlikely that the entire amount would wipe off in normal use.
“Ideally, there wouldn’t be any at all,’ said Janelle Witzel of Environmental Defence, a group lobbying against harmful chemicals.
“One of our main concerns is potential ingestion,’ she said. “After handling a receipt or before a meal, like everything else, just be sure to wash your hands.’
Other suggestions include keeping receipts away from children and toddlers, and separate from unpackaged foods in grocery bags.
It’s difficult to avoid BPA in receipts.
“Anywhere you go now, minus a few mom-and-pop stores, you look at your receipt and it’s thermal paper,’ said Jesse Gonzalez, an employee at Wedge Paper Products.
The Mississauga, Ont.-based company distributes cash register paper rolls to businesses across North America. “The quickest way to tell is by taking your fingernail and scratching it. It’ll leave a mark and that’s how you can tell it’s thermal paper.’
Gonzalez said BPA-free thermal paper is more expensive to produce.
However, he said right now about half of his company’s shipments are BPA- free, because customers are requesting it.
Prior to the receipt studies, scientists had focused on BPA exposure from food packaging.
In 2009, Health Canada measured the amount of BPA that seeped into canned soft drinks from the cans’ inner lining. On average, 0.2 micrograms of BPA were ingested with each soft drink – a fraction of the amount wiped off a receipt.
In animal tests, BPA has been linked to ovarian and prostate cancer, obesity and diabetes, among other illnesses. Earlier this month, Statistics Canada released a study estimating that 91 per cent of Canadians had measurable levels of BPA in their urine.