TiO_2-based nanoparticles released in water from commercialized sunscreens in a life-cycle perspective: Structures and quantities

摘要

This work investigates the physical-chemical evolution during artificial aging in water of four commercialized sunscreens containing TiC>2-based nanocomposites. Sunscreens were analyzed in terms of mineralogy and TiO_2 concentration. The residues formed after aging were characterized in size, shape, chemistry and surface properties. The results showed that a significant fraction of nano-TiO_2 residues was released from all sunscreens, despite their heterogeneous behaviors. A stable dispersion of sub-micronic aggregates of nanoparticles was generated, representing up to 38 w/w% of the amount of sunscreen, and containing up to 30% of the total nano-TiO_2 initially present in the creams. The stability of the dispersion was tested as a function of salt concentration, revealing that in seawater conditions, a major part of these nano-TiO_2 residues will aggregate and sediment. These results were put in perspective with consumption and life cycle of sunscreens to estimate the amount of nano-TiO_2 potentially released into AQUATIC environment.