Long-term trends and patterns of legacy and emerging cosmetic UV filters in German waters

Organic UV filters contained in sunscreens and other cosmetics can potentially end up in the aquatic environment. Various studies have demonstrated that UV filters are widespread in water bodies, yet there is a lack of comprehensive understanding of their spatial and temporal distribution in Germany. The objective of this study is to investigate the occurrence of this group of substances in suspended particulate matter (SPM) and water samples, and to explore potential links to market changes reported in the literature. We developed an analytical target method in which SPM was extracted using accelerated solvent extraction (ASE), the extracts were purified, and then analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with a quadrupole time-of-flight (Q-TOF) mass analyzer. The method detected 10 of 12 organic UV filters in SPM samples from the German Environmental Specimen Bank (ESB). Avobenzone (BMDBM) and iscotrizinol (DBT) showed average concentrations of 105 ng/g dry weight (dw) and 34 ng/g dw, respectively, in 2022. DBT showed a comprehensive significant upward trend at all Rhine stations monitored between 2005 and 2022. Diethylaminohydroxybenzoylhexyl benzoate (DHHB) also showed a clear and statistically significant upward trend at these stations, with a notable increase since 2017 at the Koblenz station. High-resolution mass spectrometry (HRMS) non-target screening (NTS) data confirmed the presence of additional polar organic UV filters in SPM and water samples, specifically camphor benzalkonium methosulfate (CBM), 4-aminobenzoic acid (PABA), ensulizole (PBSA), and sulisobenzone (BP-4). We recommend using a combination of target and NTS methods to achieve a comprehensive assessment of water pollution.