Occupational exposure of cashiers to Bisphenol A via thermal paper. Urinary biomonitoring study

Publication

Purpose
As an essential component of polycarbonate plastics and epoxy resins, Bisphenol A (BPA) is found in numerous industrial and consumer products. BPA may cause adverse health effects because of its endocrine activity. General population exposure to this compound mainly through diet is well documented. Thermal paper was also identified as a source of BPA through dermal intake. In this study, we investigated whether frequent contact with thermal paper is associated with an increase in urinary BPA excretion.
Methods
We evaluated the exposure to BPA in cashiers and in non-occupationally exposed workers and from several workplaces. Urinary BPA was quantified in free (unconjugated) and total (unconjugated plus conjugated) forms in 24-h and spot urine samples using liquid chromatography tandem mass spectrometry (LC-MS/MS). BPA concentration in thermal paper was also measured from each workplace. In addition, participants provided information on job, food and drink, tobacco consumption, hands wash, adhesives and paints uses during the sampling period through a questionnaire. Descriptive and inferential statistical analyses were performed and a mixed linear regression model was used to test the effects of different factors on urinary BPA concentrations.
Results
We collected 390 urine samples from 90 cashiers and 195 urine samples from 44 controls. Free BPA and total were detected in 100 % of samples. The median urinary total BPA concentration was 3.54 µg/L (2.89 µg/g creatinine) for controls and 8.92 µg/L (6.76 µg/g creatinine) for cashiers. For the free BPA, the median urinary concentration was 0.20 µg/L (0.21 µg/g creatinine) for controls and 0.28 µg/L (0.22 µg/g creatinine) for cashiers. We did not find any correlation between the urinary concentration levels and the number of thermal receipts handled. Hand washes frequency, age, job length of service and tobacco consumption had also no effect on the BPA excretions.
Conclusion
A significant increase in urinary total BPA concentration was observed for cashiers handling daily thermal paper receipts. However, no significant increase was observed in urinary free BPA concentration. These findings are particularly interesting for risk assessment since all available data on occupational exposure to BPA through thermal paper were obtained from models or from simulated experiments.