IDENTIFICATION, PHYSICOCHEMICAL CHARACTERISATION AND PRELIMINARY RISK ANALYSIS OF TITANIUM DIOXIDE PARTICLES IN FACE MASKS Intermediate report TiO2-Mask COVID-19 project September 2021

In situ analysis of titanium dioxide (TiO2) particles in face masks demonstrated the presence of agglomerated TiO2 (nano)particles in all examined face masks that contain polyester or polyamide (nylon) fibres, or that are made of non-woven, synthetic fabrics. These particles resemble fibre-grade TiO2 particles. Because there are no methods available for measuring exposure directly, the methodology that ANSES applied to determine the professional exposure limits to titanium dioxide in its nanoform, was applied for a scenario with intensive use of face masks. Our calculations show that a health risk cannot be excluded for most of the examined face masks when intensively used. The applied approach may overestimate the health risks because of the conservative inhalation exposure assumptions. However, for some face masks the amount of titanium dioxide is so high that a health risk cannot be excluded even when only a small fraction of the titanium dioxide particles are released and inhaled. Currently, we have no indications that TiO2 particles are released in amounts which might result in public health risks, but so far, research and publications of TiO2 particles in textiles, and particularly of their release, are limited. In view of EFSA’s conclusion that TiO2 cannot be considered any longer as safe to be used as a food additive because a concern for genotoxicity cannot be ruled out, it is advisable to issue precautionary standards to limit the presence of TiO2 particles in face&nbsp;masks.</p

Evaluation of the types, efficient use and health risks of application of silver-based biocides to provide antimicrobial properties to face masks applied during the Covid-19 crisis

In situ analysis of silver based biocides in face masks using electron microscopy and EDX, combined with total silver measurement using ICP-MS or ICP-OES demonstrated the presence of varying amounts and different types of silver-based biocides in a selection of face masks on the Belgian market and intended to be worn by the general public. Following types of silver-based biocides were demonstrated: (i) Ag+ ions, (ii) metallic Ag0 NP distributed in the matrix of the fibers, (iii) Ag NP and large silver particles at the surface of, or close to cotton fibres in face masks containing polycationic polymers binding Ag+ ions, and (iv) a coating consisting of metallic silver releasing Ag+ ions, Ag0 NP and large silver&nbsp;particles. For metallic and ionic silver, an acceptable exposure level (AELmask) of 25 µg per mask was established based on occupational exposure levels and assuming an intensive exposure scenario considering subchronic exposure of the general adult&nbsp;population. Comparison of the measured amount of total silver in the masks with this AELmask indicated that seven out of nine face masks, with a silver biocide based on Ag+ ions only, can be considered as safe. The two other face masks with a silver biocide based on Ag+ ions require a more refined risk&nbsp;evaluation. The amount of silver in the four masks that contain Ag0 NP, Ag+ ions, and/or non-nanoparticulate silver exceeded the AELmask. Per case an in depth risk analysis needs to be undertaken to account for the different forms of silver that are potentially released from face masks treated with the applied silver-based&nbsp;biocides.</p

Dietary intake of hexabromocyclododecane diastereoisomers (α-, β-, and γ-HBCD) in the Belgian adult population.

&lt;p&gt;A study was performed to assess exposure of the Belgian population to HBCD diastereoisomers. Measurements of HBCD were performed by UPLC-MS/MS, on 45 composite samples from 5 major food groups: dairy (products), meat (products), eggs, fish (products) and a group of &quot;other&quot; products. The medium bound estimated average daily intake (EDI) of ΣHBCD in the Belgian population was 0.99 ng kg(-1)bw d(-1). The diastereoisomer contribution to the mean EDI showed a predominance of γ-HBCD at 67%, followed by α-HBCD at 25% and 8% for β-HBCD. These results are consistent with the pattern found in the two food groups contributing the most to the EDI: meat (products) and the group of &quot;other&quot; products. Anyway, it has to be noted that diastereomeric distribution of HBCD can change due to bioisomerisation in biological material. Levels of HBCD diastereoisomers found in Belgian food samples of animal origin were low in comparison with those found in other EU countries and the resulting EDI was substantially below the proposed thresholds.&lt;/p&gt;</p

Titanium dioxide particles frequently present in face masks intended for general use require regulatory control

Although titanium dioxide (TiO(2)) is a suspected human carcinogen when inhaled, fiber-grade TiO(2) (nano)particles were demonstrated in synthetic textile fibers of face masks intended for the general public. STEM-EDX analysis on sections of a variety of single use and reusable face masks visualized agglomerated near-spherical TiO(2) particles in non-woven fabrics, polyester, polyamide and bi-component fibers. Median sizes of constituent particles ranged from 89 to 184 nm, implying an important fraction of nano-sized particles (< 100 nm). The total TiO(2) mass determined by ICP-OES ranged from 791 to 152,345 µg per mask. The estimated TiO(2) mass at the fiber surface ranged from 17 to 4394 µg, and systematically exceeded the acceptable exposure level to TiO(2) by inhalation (3.6 µg), determined based on a scenario where face masks are worn intensively. No assumptions were made about the likelihood of the release of TiO(2) particles itself, since direct measurement of release and inhalation uptake when face masks are worn could not be assessed. The importance of wearing face masks against COVID-19 is unquestionable. Even so, these results urge for in depth research of (nano)technology applications in textiles to avoid possible future consequences caused by a poorly regulated use and to implement regulatory standards phasing out or limiting the amount of TiO(2) particles, following the safe-by-design principle