Evaluation of environmental exposure to nanoparticulate TiO2 UV-filters used in sunscreens
Résumé
The impacts of sunscreens on both human and environmental health remain of concern as widespread use continues and new formulations are developed. While titanium dioxide (TiO2) nanoparticle UV-filters may offer a safer alternative to organic filters, their fate and impact are not fully understood and resulting regulation is still under consideration due to their potential risk to consumers and the environment.
After leaving the skin either through swimming or everyday use and subsequent washing, the TiO2 nanomaterials contained in the sunscreen can be released into rivers, lakes, sea shores, and/or sewage treatment plants. Their fate and impact in these different systems is largely determined by their surface properties (e.g., coating type and life-time). Consequently, every stage of the sunscreen life-cycle must be considered, from manufacturing and consumer use to end-of-life and impact on the exposed environment. In this work, both field and laboratory studies were developed to assess environmental exposure to UV-filters from sunscreen.
For the field campaign, sea water samples were collected from three French beaches before and during the height of summer recreational activities. The quantity of sunscreen used at each beach was estimated using attendance numbers and responses from a social survey, while the actual concentrations of UV filters (organic and mineral) recovered in the waters were determined at different depths and distances from the shore. In this way, both UV-filter release and exposure in a littoral zone could be evaluated.
Additionally, sunscreens were formulated in the laboratory and studies conducted to investigate risk to the direct aquatic environment as well as risk related to product end-of-life. These insights will help guide regulations, provide better information for consumers, and assist manufacturers in incorporating an eco-design approach in consumer product development.