Quantification of trace elements in surgical and KN95 face masks widely used during the SARS-COVID-19 pandemic

During the current coronavirus disease (COVID-19) pandemic, face masks have been the single most important protective equipment against the threat of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). While masks are worn, both the nose and the mouth of the user come in contact with the mask material, and as the latter mediates the inhaled air and may interfere with the swallowed saliva, it is of paramount importance to assure that the mask is free of toxic substances. As there are currently no studies on the total amount of trace elements in masks, the present study fills the void and investigates 24 surgical and KN95 face masks. Specifically, mask samples were analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to determine the total concentrations of trace elements as well as to assess the possibility that any detected of the elements present could transfer into the human body, based on saliva leaching and breathing experiments. Accordingly, it is reported herein that although most masks analyzed in this study contain trace elements below their corresponding detection limits, a few masks did contain detectable levels of trace elements. In particular, the maximum values that were determined in certain analyzed samples were: Pb (13.33 μg g^-1), Cu (410 μg g^-1), Zn (56.80 μg g^-1), and Sb (90.18 μg g^-1). Finally, in the masks that Pb was present, it easily leached out (58% transfer during a 6-h exposure) during the saliva simulation experiments.