Evaluation of the significance of UV filters from sunscreens in Swiss bathing lakes

In Lake Geschiner, the Ecotox Centre has detected UV filters in concentrations that in some cases were in the same order of magnitude as preliminary quality criteria for these substances, meaning that a risk to aquatic organisms cannot be ruled out. In order to assess the significance of UV filters from sunscreens for Swiss bathing lakes, five bathing lakes (Crestasee, Canovasee, Hüttnersee, Greifensee und Geschinersee) will be regularly sampled in summer 2024 and chemically analysed for the most common UV filters. Robust quality criteria are to be determined for selected substances that prove to be problematic, so that a risk assessment of these UV filters for aquatic organisms is possible. For the risk assessment for sediment organisms, the toxicity to sediment organisms will be determined in bioassays. In addition, bathing tests in test ponds are planned in order to track the flux of the UV filters from the skin into the water and the further fate of the substances.