BPA in cash register receipts

Posted on: Sat, 06/12/2010 - 17:15 By: Tom Swiss

Following up on the topic of the endocrine disruptor bisphenol A (BPA), it seems that exposure from water bottles and other plastic food and beverage containers may be dwarfed by that caused by a surprising source: cash register receipts and other papers from thermal printers, and also carbonless copy papers. (Thanks Sean McCutcheon for the tip.)

These printing technologies rely on paper impregnated with zillions of microcapsules containing ink or dye; pressure or heat breaks the capsules and lets the ink out. (Fun fact: up until 1970, the dye was often made with polychlorinated biphenyls -- PCBs, delightfully toxic chemicals). In some methods, the paper has to be coated with a developer that reacts with the dye; that's where "phenolic resins" like BPA come in.

And unlike the polycarbonate -- a polymer that's a long string of BPA molecules -- that's in containers, which has to break apart to expose you, the BPA in paper is the raw stuff. Where exposure from a polycarbonate water bottle is measure in nanograms, a single cash register receipt can contain 60 to 100 milligrams of free BPA -- millions of times as much.

That is, it's the difference between .000000001 grams, and .06 to .10 grams.

Of course, you're probably not chewing on your receipt; but once on the fingers, BPA can be transferred to foods. And it is know that some And some hormones can be absorbed through the skin; it does not seem to be known if this applies to BPA or not.

As a result of this use, BPA derivatives have been found in effluent from paper recycling.