"1. Introduction
... Available characterizations of facemasks reveal the presence of chemicals like hydrocarbons, phthalates, organo phosphate ester compounds, amides, paraffins, olefins, polyethylene terephthalate oligomers and microplastics (Kutralam-Muniasamy et al., 2022; Li et al., 2021a; Liu et al., 2022a; Muensterman et al., 2022). It is known from environmental research that the COVID-19 pandemic was exacerbated by environmental pollution, entailing (or bringing about) increased concerns. A recent comprehensive review on uptake, toxicity, and molecular targets of microplastics and nanoplastics impacting human health significantly mentioned face masks as a source of inhalation risk (Khan and Jia, 2023). Also, numerous environmental toxicology reviews (Chen et al., 2022; Ganesapillai et al., 2022) derive an indirect (environmental) health risk from wearing face masks due to the release of chemical additives (Aerts et al., 2020; Raval and Sangani, 2021) and (micro)plastic fibers (Li et al., 2022; Morgana et al., 2021; Shen et al., 2021). Face masks released contaminants (microplastics/fibers/chemical compounds) disturbing several ecosystems and affecting their biota (Masud et al., 2023; Oliveira et al., 2023). Those contaminants can induce multi-organ toxicity on a wide range of aquatic and terrestrial organisms...
However, so far direct risks associated with using face masks and their repercussions on human health had only been explored from a scientific and not from a holistic perspective (Potluri and Needham, 2005). Potentially, face masks, that come into close contact with the consumer can pose an immediate threat to human health due to the release of toxicologically relevant substances and continuous exposure to them (Jin et al., 2021; Liu et al., 2022a). Humans inhale emissions from a mask at nearly zero distance and swallow water droplets originating from the moist dead space enriched with mask ingredients. In this regard – theoretically – wearing a mask may exert a higher risk of exposure than many other environmental sources (Chang et al., 2022)...
Chemical toxic additives used in the manufacturing processes of masks, including plasticizers, phthalates, UV stabilizers, and bisphenol A have already been shown to leach and cause adverse health effects in humans (De-la-Torre et al., 2021). Children with less developed protective/conjugative pathways (Faustman et al., 2000) are particularly vulnerable to many of the face mask emissions...
Inspired by scientific reports and the undisputed fact that masks are capable of causing inhalation of potentially toxic substances (Li et al., 2022; Mast et al., 2023; Masud et al., 2023; Palmieri et al., 2021) we decided to conduct a scoping review on this topic in order to evaluate reliable scientific data on toxic content and release from face masks. Moreover, we initially aimed for the assessment of the potential exceedances of toxin thresholds associated with face mask use...
4. Discussion
The results of our review show that ingredients of mask manufacture/production play a key role in their potential toxic properties. We also found clear evidence that values of certain contents/emissions are alarmingly high in all scrutinized mask types (N95, surgical, textile) and may – in worst case scenarios – pose a health risk to the wearer, who inhales the toxic substances at nearly zero distance. In the following subheadings we discuss the origin, the release and risks of particular toxics and compare our results of the contents and releases from masks to the threshold limit values of air- or textile concentrations, if available, from international organisations and institutions...
4.3. Specific organic compounds: organophosphate esters (OPEs) and Organophosphate flame retardants (OPFRs) ...
4.3.2. OPEs and OPFRs from masks – release/intake
All masks analyzed in the included studies presented an OPE [organophosphorus esters] contamination, with maximal values up to 27.7 µg/mask in the FFP3. The maximal OPE values for N95 masks was 20.4 µg and for surgical masks 0.717 µg (Fernández-Arribas et al., 2021). Interestingly, the higher OPE levels were found in N95 masks, while the lowest values were those of surgical masks...
4.3.4. OPEs and OPFRs– risks
OPEs are associated with asthma and allergies, some harbour cancer risks (US EPA, 2015b)."
© 2023 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/bync-nd/4.0/).