Release of Titanium Dioxide from Textiles during Washing L. Windler, † C. Lorenz, †,‡ N. von Goetz, ‡ K. Hungerbü hler, ‡ M. Amberg, § M. Heuberger, § and B. Nowack †, * † EmpaSwiss Federal Laboratories for Materials Science and Technology, Technology and Society Laboratory, 9014 St. Gallen, Switzerland ‡ ETH Zü rich, Institute for Chemical and Bioengineering, 8093 Zü rich, Switzerland § EmpaSwiss Federal Laboratories for Materials Science and Technology, Laboratory for Advanced Fibers, 9014 St. Gallen, Switzerland * S Supporting Information ABSTRACT: Nano-TiO 2 has the highest production of all nanomaterials, and pigment-TiO 2 is a commodity used on the million tons/year scale. Information on the release of TiO 2 from consumer products is therefore an important part of analyzing the potential environmental exposure to TiO 2 . For this study, we investigated the release of TiO 2 from six different functional textiles during washing. TiO 2 is used in textiles because of its UV-absorbing properties and as pigment. Analysis of fiber cross sections showed that the TiO 2 was contained in the fiber matrix. The sun-protection textiles had Ultraviolet Protection Factors that were between 58 and 6100 after washing and therefore above the labeled factor of 50+. Five of the textiles (sun-protection clothes) released low amounts of Ti (0.01 to 0.06 wt % of total Ti) in one wash cycle. One textile (with antimicrobial functionality) released much higher amounts of Ti (5 mg/L, corresponding to 3.4 wt % of total Ti in one wash cycle). Size fractionation showed that about equal amounts were released as particles below and above 0.45 μm. After 10 washings, only in two textiles significantly lower Ti contents were measured. Electron microscopy showed that the TiO 2 particles released into washing solution had a roundish appearance with primary particle sizes between 60 and 350 nm that formed small aggregates with up to 20 particles. The results indicate that functional textiles release some TiO 2 particles, but that the amounts are relatively low and mostly not in the nanoparticulate range. ■ INTRODUCTION Nano-TiO 2 is of all engineered nanomaterials (ENM) the one with the highest production amount; 1 it has an estimated yearly production of 7800-38 000 tons in the U.S. 2 The main uses of nano-TiO 2 are as a UV-absorber in sunscreens 3 and as photocatalytic coatings. 4 The incorporation of nano-TiO 2 into textiles increases their UV-protection factors 5 and has also been proposed as a promoter of antimicrobial activity. 6 Modeling studies have shown that nano-TiO 2 is the ENM with the highest expected environmental concentration in water, soil and sediments. 7-9 The transfer into wastewater treatment plants is the most important flow of nano-TiO 2 into the environment; caused by applications such as sunscreens that have direct contact with water. There is almost no information available on the release of TiO 2 or nano-TiO 2 from products. 10,11 Nanosized TiO 2 was found to have been released from painted facades and was detected subsequently in natural waters. 12 Nano-TiO 2 is released from sunscreens, but only a fraction of the released material is present in the nanorange, whereas the largest part forms large agglomerates. 13 Conventional TiO 2 is used in numerous consumer and industrial applications as pigment to increase their whiteness or opacity, such as paints, coatings, plastics, paper, food, personal care products, including sunscreens. 4 In textiles, pigment TiO 2 is incorporated in most synthetic fibers as delustrant. 14 The estimated worldwide production of TiO 2 is 4 million tons. 15 TiO 2 found in the environment can have either natural or anthropogenic origins. 16 Natural TiO 2 nanocrystals have been found occurring in river water impacted by mining activities. 17,18 Kiser et al. 19 reported the occurrence, character- ization, and removal of nano- and larger-sized TiO 2 in wastewater treatment plants. The influent into the investigated treatment plants was found to contain between 181 and 1233 μg/L Ti 20 (which was considered to be present in the form of TiO 2 ). The size fraction larger than 0.7 μm accounted for the majority of the Ti in the influent, and 95% of this fraction was Received: April 24, 2012 Revised: June 27, 2012 Accepted: June 29, 2012 Published: July 2, 2012 Article pubs.acs.org/est © 2012 American Chemical Society 8181 dx.doi.org/10.1021/es301633b | Environ. Sci. Technol. 2012, 46, 8181-8188