High levels of possible carcinogens found in face masks

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Although titanium dioxide (TiO2) is a probable human carcinogen when inhaled, fiber-grade TiO2 nanoscale particles have been found in the man-made textile fibers of face masks for public use, as reported in an article published in the journal Scientific reports.

Study: Titanium dioxide particles frequently found in general purpose face masks require regulatory control. Image Credit: evrymmnt/Shutterstock.com

TiO2 in Face Masks

Face masks are a crucial and frequently used public protection strategy in the fight against the SARS-CoV-2 (COVID-19) virus.

In a recently conducted study that tested many sets of face masks intended to be sold as personal protective equipment (PPE), it was found that TiO2 was present in amounts ranging from 100 to 2000 mg kg-1.

TiO2 is widely used in face mask materials, as well as a wide range of other fabrics, for example, to increase UV light stability, as a bleaching agent or as a matting material. Additionally, fabric companies are fusing particular nanofiber, nanocomposite, and nanoparticle technologies into face masks to provide new answers to issues related to the COVID-19 outbreak.

Antimicrobial screens made from nanofibers containing TiO2 nanoparticles, as well as graphene and silver, have been developed. TiO2 layers of nanoparticles on cotton fabrics have been used to enhance self-cleaning and antimicrobial qualities.

HAADF-STEM images of sections of different fiber types seen in face masks, with (a) polyester, (b) polyamide, (c) two-component microfiber, (d) cotton, (e) heat-bonded nonwoven fiber, ( f) melt blown nonwoven fabric.  TiO2 particles are visible as bright white dots.

Figure 1. HAADF-STEM images of sections of different types of fibers seen in face masks, with (a) polyester, (b) polyamide, (vs) two-component microfiber, (D) cotton, (and) heat-bonded nonwoven fiber, (F) melt blown nonwoven fabric. TiO2 the particles are visible as bright white dots. © Verleysen, E., Ledecq, M., et al. (2022).

Why is this a bad thing?

There is growing concern about the potential long-term implications of insufficiently controlled use of nanomaterials in fabrics to improve the effectiveness of PPE.

Toxicities have been observed in animal studies when TiO2 the nanoparticles were breathed in as well as taken orally. In 2017, the Committee for Risk Assessment (RAC) of the European Chemicals Agency (ECHA) considered the carcinogenic potential of TiO2 and suggested classifying it as Carc. 2, H351 (suspected human carcinogen) via the respiratory route. TiO2 has been assigned this CLP categorization.

How the research was conducted

To determine whether titanium dioxide nanoparticles in PPE masks pose a health concern, their quantities, physicochemical qualities, and location were examined in a variety of face masks. Based on these observations, the amount of TiO2 at the face of the mask, the fibers were determined and compared to the permissible respiratory levels of exposure to TiO2given by mask (AELmask).

Important takeaways from the study

In this study, the team found many important issues related to the characterization, evaluation and risk assessment of TiO2 in PPE masks that are outside the scope of the research.

Generally, there is little research data on the existence of nanomaterials in face masks, their properties, exposure and risks to the public. TiO analysis methods2 nanoparticles in PPE masks are time-consuming and expensive.

Despite the fact that this research focused on PPE masks intended for the general population, TiO2 nanoparticles can be found in other types of masks using artificial fibers, such as surgical masks, even if they are approved.

STEM-EDX analysis of particles (a) in a polyester fiber, (b) at the edge of a polyester fiber, (c) in a bicomponent microfiber and (d) in a nonwoven fabric.  (first column) Low magnification HAADF-STEM images show cross-sections of fibers containing the analyzed particles (white arrows) shown in higher magnification HAADF-STEM images (second column).  (third column) The spectral images of Ti (green) obtained by EDX show that the measured Ti signal coincides with the position of the particles shown in the STEM image, and (fourth column) the EDX spectra of the area indicated in the image STEM display Ti signal.

Figure 2. STEM-EDX analysis of particles (a) in a polyester fiber, (b) bordering a polyester fiber, (vs) in a two-component microfiber and (D) in a non-woven fabric. (first column) Low magnification HAADF-STEM images show cross-sections of fibers containing the analyzed particles (white arrows) shown in higher magnification HAADF-STEM images (second column). (third column) The spectral images of Ti (green) obtained by EDX show that the measured Ti signal coincides with the position of the particles shown in the STEM image, and (fourth column) the EDX spectra of the area indicated in the image STEM display Ti signal. © Verleysen, E., Ledecq, M., et al. (2022).

The current investigation into face masks for the ordinary person should be expanded to investigate possible health concerns related to the incorporation of titanium dioxide nanoparticles into surgical masks and PPE, as well as on-site exposure. resulting work.

The destination and procedures for discharging nanoparticles from face masks are still unclear; for example, nanoparticles can be released as individual particles, aggregates, aggregate-bearing fiber fragments, or a mixture thereof.

Aggregates are hypersensitive to environmental variables such as acidity, protein content, ionic strength, and movement through the carrier medium, and can disaggregate or aggregate further depending on environmental conditions.

Although this results in complicated particle behavior in contact situations as well as tissue uptake and biodistribution, the impact on cytotoxicity or biological reactions remains unknown.

Hazard data (respiratory toxicity threshold) of individual TiO2 nanoparticles included in PPE masks must be obtained through rigorous and repetitive dose inhalation research using fiber-grade TiO2 nanoparticles. In addition, further toxicological and epidemiological studies are needed to determine the hazard of susceptible groups, especially children.

The need to use face masks while battling COVID-19 cannot be overstated. Nevertheless, these results call for further investigation of nanomaterials in tissues to avoid potential future implications of unregulated use and to enforce regulatory requirements to phase out or restrict the percentage of TiO.2 nanoparticles, in accordance with the concept of safety by design.

Reference

Verleysen, E., Ledecq, M., et al. (2022). Titanium dioxide particles frequently found in general purpose face masks require regulatory control. Scientific reports, 12. Available at: https://www.nature.com/articles/s41598-022-06605-w

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