MedicalResarch.com Interview with:
Julia A. Taylor, Ph.D.
Assistant Research Professor
Division of Biological Sciences
University of Missouri Columbia, MO 65211
Medical Research: What is the background for this study? What are the main findings?
Dr. Taylor: Bisphenol A (BPA) is an industrial chemical present in a large number of consumer products, including polycarbonate plastics, food can linings, resins and thermal paper. A 2008 study of BPA levels in human urine concluded that over 90% of the U.S. population is exposed to BPA. BPA is an endocrine disrupter; its estrogenic properties were first described long before its commercial use, but today it is known that it not only acts like an estrogen but also interferes with thyroid hormone, androgen and insulin action. In population-based studies, higher urinary levels of BPA have been linked to a number of human health issues. For example, higher BPA concentrations have been associated with obesity and aggressive and hyperactive behaviors in children, and with cardiovascular disease and diabetes, altered liver and kidney function, and immune and reproductive disorders in adults.
It was at one time thought that almost all human exposure occurs via food and drink, but calculations of exposure from these sources do not adequately account for the sometimes high amounts measured in urine, and the fact that BPA concentrations in population-based studies are not lower with increasing fasting time suggests that some other form of ongoing exposure. Our interest here was in thermal paper. BPA has been used as a color developer in thermal paper for many years and can be present in milligram amounts in the paper coating. Because thermal printing is widely used for items such as sales and ATM receipts, airline tickets and luggage labels, thermal paper may represent an important high-concentration source of exposure.
We screened thermal paper receipts from 50 in-state vendors and found that 44% used BPA as the color developer, but 52% used another chemical called BPS (bisphenol S) which was present in similar quantities to BPA. Two receipts contained neither BPA nor BPS, and so presumably used an alternative (unidentified) chemical.
In preliminary work we measured the transfer of BPA from thermal paper to the hands, and found much higher transfer to hands that were pre-wet using hand sanitizer. We also determined that BPA transferred to hands could then be transferred to food. In our study we asked men and women to first wet their hands with sanitizer before holding the receipts for a few minutes, and then with the same hands pick up french fries and hold them briefly before eating them. We then cleaned one hand but allowed the other to remain “contaminated”. We took blood samples over the next 90 minutes, either from the arm linked to the clean hand or the arm linked to the dirty hand, and collected a urine sample at the end.