Transfer of bisphenol A from thermal printer paper to the skin

Sandra Biedermann, Patrik Tschudin, Koni Grob

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 microg BPA (0.2-6 microg) 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 microg/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.