Bisphenol A in Disposable Face Masks: A Novel Human Exposure Pathway and Impact on the Aquatic Environment

We identified and quantified bisphenol A (BPA), a known estrogen-like endocrine disruptor, in disposable face mask samples collected in Hong Kong. Results revealed that BPA is a common contaminant in face masks, with concentrations reaching up to 2 μg/mask. Although polypropylene, the primary material used in mask production, is generally considered to be BPA-free, the contaminant likely originates from additives, such as flame retardants, added during manufacturing. With a dermal absorption coefficient of 0.59 for BPA, the data indicate that mask-borne BPA is readily absorbed by the skin. Notably, 8 of 85 samples could cause the user to exceed the tolerable daily BPA intake set by the European Food Safety Agency (0.0002 μg/kg body weight per day). Additionally, BPA dissolves completely in landfill leachate in less than 70 days, which poses previously unrecognized health and environmental hazards. Given the extensive use of face masks during the pandemic, their role as personal protective equipment for medical practitioners, and the fact that there are currently no regulations regarding BPA contents in masks, it is imperative to investigate the need for regulations in order to safeguard face mask users and the environment.