Engineered nanoparticles (ENP) are increasingly used to functionalize textiles, for example, the antimicrobial activity of Ag-ENP or the UV-absorption of TiO₂-ENP are used. However, it still is unclear to which extent nanoparticles migrate from the textile into human sweat and are taken up by the skin, as no experiments with realistic exposure scenario have been performed.
Textiles in the EU are treated as articles, therefore, substances in them do not need to be listed on a product label or be evaluated according to their potential for consumer exposure. Also no registration is required in many EU countries.

Natalie von Götz, ETH Zurich, Switzerland, and colleagues constructed a realistic exposure scenario for measuring how much of the materials migrate into artificial sweat when wearing Ag- and TiO₂-ENP-containing commercially available textiles during sports activities.

On the basis of their experiments, the team calculated the external dermal exposure rates to Ag and TiO₂ for male and female adults per use. In comparison with other human exposure pathways, dermal exposure to nanoobjects and their aggregates and agglomerates (NOAA) from textiles can be considered comparably minor for TiO₂-NOA, but not for Ag-NOAA. However, due to their much smaller percutaneous uptake rates Ag-NOAA on the skin presumably cause much less internal exposure and thus have far less toxic potential than orally administered Ag-ENP in dietary supplements, the researchers say.

• Migration of Ag- and TiO₂-(nano)particles from textiles into artificial sweat under physical stress: Experiments and exposure modeling,
  Natalie von Götz, Christiane Lorenz, Lena Windler, Bernd Nowack, Manfred P. Heuberger, Konrad Hungerbuehler,
  Environ. Sci. Technol. 2013.
  DOI: 10.1021/es304329w