Detection of bisphenol A in thermal paper receipts and assessment of human exposure: A case study from Sharjah, United Arab Emirates

**Background:** Bisphenol A (BPA) is a synthetic xenoestrogen used as a color developer in thermal paper receipts. It is an endocrine disruptor that can enter the body via dermal contact, with the unconjugated form binding to estrogen receptors. Thermal paper handling is a major source of dermal BPA exposure, and sanitizers can increase dermal penetration up to 100-fold. The EU set a limit of <0.02% by weight (200 ng/mg) for BPA in thermal papers, effective January 2020. This study is the first to investigate BPA concentrations in thermal paper receipts in the UAE.

**Methods:** Thirty thermal paper receipt samples were randomly collected from supermarkets (n=11), restaurants (n=6), ATMs (n=6), and other locations (n=7) in Sharjah, UAE. Samples (25 mg each) were extracted in 50 ml distilled water for 60 minutes at room temperature and analyzed using HPLC-MS with an Acquity UPLC connected to ESI Xevo TQD. The mobile phase consisted of water and methanol at 0.3 mL/min. BPA was detected in negative ion mode MRM (227.1→211 quantitative, 227.1→133 qualitative). Weight-adjusted estimated daily intakes (EDI) were calculated using the formula: EDI = (k × C × HF × HT × AF) / BW, where k (paper-to-skin transfer coefficient) was 1072, 1838, or 21522 ng/s; C was BPA concentration (μg/g); HF was handling frequency (2 times/day for general population, 96 times/day for cashiers); HT was handling time (5 seconds for general population, 10 seconds for cashiers); AF was absorption fraction (2.3%, 8.6%, or 27%); and BW was 60 kg for females and 70 kg for males.

**Key Results:** BPA concentrations ranged from <0.02 ng/mg to 978.2 ng/mg. Sixty percent (60%) of samples exceeded the EU limit of 200 ng/mg: 54.6% of supermarket receipts, 50% of restaurant receipts, 83.3% of ATM receipts, and 57.1% of other receipts. Forty percent (40%) of samples had BPA levels below 0.02 ng/mg. Maximum concentrations were highest in restaurant receipts (978.2 ng/mg) and lowest in ATM receipts (776.2 ng/mg). For the general population, EDIs ranged from 8.22×10⁻¹¹ to 0.000812 μg/kg bw/day, with the highest from restaurant receipts. For cashiers, EDIs ranged from 7.89×10⁻⁹ to 0.0681 μg/kg bw/day. All EDIs were below the EFSA TDI of 4 μg/kg bw/day and Health Canada's provisional TDI of 25 μg/kg bw/day. However, cashier EDIs under the most aggressive scenario (k=21,522, AF=27%) exceeded California's proposed MADL of 0.052 μg/kg bw/day for females and 0.043 μg/kg bw/day for males. Females had higher EDIs than males in all scenarios.

**Clinical Implications:** Although all calculated EDIs were below established tolerable daily intakes, 60% of receipts exceeded the EU regulatory limit, indicating widespread non-compliance. The potential for co-exposure from dietary and non-dietary sources, combined with increased sanitizer use (which can enhance dermal penetration up to 100-fold), warrants continued monitoring. Cashiers are at highest risk due to frequent and prolonged handling. The study recommends policies promoting BPA-free paper, electronic receipts, glove use, hand washing after handling receipts, and avoiding children's contact with receipts.