L Windler (2011) Ag and TiO2 particles in apparel textiles: particle characterization and quantification of release during use ETH Zurich Abstract: Nanoparticles are used to impart industrial textiles with specific functions. Silver (Ag) is used for its antibacterial property in T-Shirts, socks and other nanoproducts. Titanium dioxide (TiO2), in contrast, is widely used as a pigment in synthetic fibers. It is also used to make textiles such as T-Shirts and swimwear UV absorbent. The size of the applied TiO2 particles ranges from nanometers to micrometers. To assess the risks of nanoparticles that are released to the environment through consumer products, it is essential to quantify and characterize the release during a products life cycle. During use, a nanoproduct can release particles through abrasion, through the exposure to perspiration or through washing.
This study investigates the release of Ag and TiO2 from 13 commercially available textiles which were either antibacterial or UV protective. The release was investigated during a standardized washing procedure and during the exposure to perspiration. The released particles were then separated into different size classes and, additionally, characterized by microscopy. Also Ultraviolet Protection Factors (UPF) were determined and tracked along the washing experiments to investigate if UV protection is affected by washing.
The Ag content of the textiles ranged from 0 to 2925 μg/g and the Ti content of the textiles was between 2153 and 8543 μg/g. Four out of seven Ag containing textiles leached detectable amounts of Ag during washing. The amount of Ag leached varied remarkably amongst those samples (6.7mg/l - 688mg/l). This corresponds to an Ag release of 14 to 24% of total Ag content. In the washing as well as in the perspiration experiments five out of six TiO2 containing textiles leached less than 0.1% Ti, close or below the detection limit. One TiO2 containing textile leached up to 4.7mg Ti/l titanium into the washing solution and up to 6.3mg Ti/l into the artificial sweat (pH 5.5). This corresponds to 3.3% of the total Ti content, and 4.3% respectively. Electron microscopy provided evidence that Ag is released in different forms, i.e. as metallic Ag, AgCl, Ag2S and possibly as TiO2/AgCl or TiO2/Ag and that TiO2 is mostly released in the form of aggregates.
The results showed different release characteristics among the textiles, in terms of amount as well as in the form of the released particles. Depending on the textile the nano-sized fraction was more or less important. This clarifies that the release depends not only on the amount of Ag or TiO2 in a textile, but also on the particle form and incorporation technique. This study expands the available data on nanoparticle release from commercially available products and will serve as an input for future studies that address the risks of nanotechnology. Based on the results of this study, future research in environmental modeling should also include the different forms of Ag and TiO2 that are released from consumer products.
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