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Technical Note

Analytical and Bioanalytical Chemistry
September 2010, Volume 398, Issue 1, pp 571-576
First online: 11 July 2010
Transfer of bisphenol A from thermal printer paper to the skin

Abstract

Of 13 thermal printing papers analyzed, 11 contained 8–17 g/kg bisphenol A (BPA). When taking hold of a receipt consisting of thermal printing paper for 5 s, roughly 1 μg BPA (0.2–6 μg) was transferred to the forefinger and the middle finger if the skin was rather dry and about ten times more if these fingers were wet or very greasy. This amount transferred to dry skin was neither significantly increased when taking hold of the paper at up to 10 sites, nor reduced when BPA-free paper was contacted afterwards. After 60–90 min, BPA applied to the skin as a solution in ethanol was only partially or no longer at all extractable with ethanol, whereas BPA transferred to the skin by holding thermal printer paper remained largely extractable after 2 h. This suggests that penetration of the skin depends on the conditions. Extractability experiments did not enable us to conclude whether BPA passes through the skin, but indicated that it can enter the skin to such a depth that it can no longer be washed off. If this BPA ends up in the human metabolism, exposure of a person repeatedly touching thermal printer paper for 10 h/day, such as at a cash register, could reach 71 μg/day, which is 42 times less than the present tolerable daily intake (TDI). However, if more than just the finger pads contact the BPA-containing paper or a hand cream enhances permeability of the skin, this margin might be smaller.

The Missouri scientists found that the total mass of BPA on a receipt is 250 to 1,000 times greater than the amount of BPA typically found in a can of food or a can of baby formula, or that which leaches from a BPA-based plastic baby bottle into its contents. These data should not be interpreted to suggest that policymakers shift their focus from BPA contamination of food, which is widespread, to receipts. BPA exposure from food sources is ubiquitous and should remain the first priority of U.S. policymakers. However, a significant portion of the public may also be exposed to BPA by handling receipts. Since many retailers do not use BPA-laden thermal paper, this particular route of exposure is easy to correct.