Human Exposure Assessment for Textiles: Proposal for a Standard Test for Migration of Chemicals from Textiles into Artificial Sweat under Physical Stress

摘要

Functional textiles are very important in our daily life. They contain a number of different chemicals that support the functionality and are often worn in direct contact with the skin, thus implying a large potential for consumer exposure. Meanwhile, no standardized tests exist for the assessment of chemical migration from textiles into sweat, which latter can be supposed to be the relevant transport medium from textiles to human skin. In order to design a setup for simulating wearing of textiles, we adapted the experimental setup of two ISO methods that are used for the assessment of color fastness for dyes used in textiles. The advantage of this design over static migration into sweat, which can be assessed by simply submersing the textile for a defined time, is that it also simulates the physical stress that textiles experience during wearing (friction and stretching). A case study was carried out with two engineered nanoparticles (ENP) that are frequently added to textiles, for antimicrobial activity or UV protection, i.e. silver (Ag) and titania (TiO2). We used 9 different commercially available textiles, four of which contained silver and 6 contained titania, presumably as TiO2 (one textile contained both metals). The textiles are shirts, trousers, underwear and socks. For the migration experiment the textiles were washed in model washing machines at room temperature. As "washing solution" artificial sweat of either pH 5.5 or pH 8.0 was used. The textile samples were exposed to sweat inside the rotating washing machines for 30 min at 40°C. Two of the four textiles released Ag in dissolved and particulate form (mainly ＜450 nm, here referred to as nanoparticulate Ag); TiO2 was only released by one textile. Human exposure modeling showed that external exposure from functionalized clothing thus may go up to 1.3 mg/d for total Ag, and 0.6 mg/d for nanoparticulate Ag. In comparison to migration experiments without physical stress we observed a larger migration.