# Personal Protective Equipment as a Potential Source of
## 4 Discussion  
### Phthalate Concentrations in Face Masks and Face Shields  
All of the tested face masks and face shields in this study contained quantifiable levels of at least two of the six target phthalates. Reusable cloth masks showed a high total phthalate contents compared with disposable masks. Total phthalate contents were in the range of 0.60-942.60 \(\upmu\)g/g. In total, three samples showed a high total phthalate content at the levels of 92.17 \(\upmu\)g/g, 503.48 \(\upmu\)g/g, and 942.60 \(\upmu\)g/g. One of these masks was commercialized for children's use; this mask contained a high level of phthalates, with a total content of 503.48 \(\upmu\)g/g, and DINP was the main plasticizer in this mask at a level of 503 \(\upmu\)g/g \(\pm\) 109 \(\upmu\)g/g. The other two masks were reusable masks for adults and contained DEHP as the main phthalate at the levels of 91.3 \(\upmu\)g/g \(\pm\) 111 \(\upmu\)g/g and 938 \(\upmu\)g/g \(\pm\) 826 \(\upmu\)g/g.  
Cloth masks with the highest levels of phthalates contained thick plastisol prints on the outer layer of the mask as decoration or with the brand's logo. The plastisol prints appeared to be the main source of the high phthalate content measured in these samples, particularly when noting the high SDs of the replicate measurements. Phthalates are a common constituent or contaminant of plastisol prints and represent a potential concern for textile manufacturers and retailers [37; 38]. DBP, DEHP, and DINP were the major phthalates detected in plastisol-printed fabric sections from five T-shirts analyzed for phthalate content [38]. These three phthalates were also found in the reusable cloth masks with plastisol prints in this study. Although the plastisol prints were on the outer layer of the mask, it is likely that they still contributed to the increasing exposure to phthalates, as phthalate compounds are semivolatile and not firmly bound to the plastic polymers. Phthalate compounds can easily leach out and migrate to the other layers of the face mask, reaching the inhalation path of the wearer. In addition to being derived from the plastisol prints, phthalates could also be present in the fabric itself. [PERSON] et al. [39] reported the prevalence of phthalates in preschool children's clothing. Total phthalate contents in the range of 2.92-223 \(\upmu\)g/g were found, with DEHP and DBP being among the most abundant phthalates. Infant cotton clothing was also reported to contain phthalates, with a total content in the range of 2.29-51.9 \(\upmu\)g/g and with DEHP being the dominant phthalate [40].  
A few recent studies [20; 31; 41; 42] have reported the levels and profiles of phthalates in disposable face masks comparable to those found in this study. DBP and DEHP were the most frequently detected phthalates in face masks, with concentrations ranging from <LOD to 4.78 \(\upmu\)g/g and from 0.037 \(\upmu\)g/g to 36.7 \(\upmu\)g/g, respectively [20; 31]. The main source of the reported phthalates was concluded to be the raw materials used to manufacture the disposable face masks. However, other potential sources were also reported, such as contamination during the production process [31] and packaging [42].  
The similarity in the results between the above studies might be related to the fact that the raw material composition and manufacturing process of face masks are similar around the world [31]. However, during the COVID-19 pandemic, there was a surge in the demand worldwide for commercial face masks, leading to a global shortage of face masks and associated raw materials. As a result, low-quality commercial masks appeared in the market, in addition to homemade masks produced from household materials such as cotton fabrics, clothing, and silk [43; 44].  
Notably, in addition to the six phthalates quantified in the face masks and face shields in this study, several other compounds were detected, including other phthalate plasticizers, flame retardants, and plastic additives, as discussed below.