Comparative physicochemical properties and toxicity of organic UV filters and their photocatalytic transformation products

• Published in: Environmental pollution (1987) 2021-10, Vol.286, p.117551-117551, Article 117551
• Main Authors: Law, Japhet Cheuk-Fung, Huang, Yanran, Chow, Chi-Hang, Lam, Tsz-Ki, Leung, Kelvin Sze-Yin
• Format: Article
• Language: English
• Subjects: Environmental fate; Micropollutants; Mobility; Persistence; Sunscreens; Transformation pathway
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2021.117551

Transformation products (TPs) of micropollutants contaminating our water resources have become an emerging issue due to the potential threats they pose to environmental and human health. This study investigated the transformation chemistry, toxicity, physicochemical properties and environmental behavior resulting from photocatalytic transformation of organic UV filters as model micropollutants. 3-Benzylidene camphor (3-BC), 4-hydroxybenzophenone (4-HB) and octocrylene (OC) were effectively degraded by UV-A/TiO2 treatment, with TPs identified and characterized with high resolution mass spectrometry. Nitrated-TPs were observed to be formed in the presence of nitrite and nitrate for 3-BC and 4-HB, suggesting that the transformation process could be altered by components in the water matrix. Vibrio fischeri bioluminescence inhibition assay revealed an increase in toxicity of TPs derived from photocatalytic treatment, with quantitative structure-activity relationship model (ECOSAR) predicted an enhanced toxicity of individual TPs' after transformation. Assessment of physicochemical properties and environmental behavior suggested that TPs as compared to parent organic UV filters, may represent even greater hazards due to their increased water solubility, persistence and mobility – in addition to retaining the parent organic UV filter's toxicity. The results provide important information relevant to the potential risks for the selected organic UV filters, and their corresponding transformation products. [Display omitted] •Transformation chemistry of selected organic UV filters was elucidated.•Transformation products were as toxic as, or more toxic than, parent UV filters.•TP-213P derived from 4-hydroxybenzophenone showed higher bioaccumulation potential.•Transformation products of 3-benzylidene camphor are toxic and more water soluble.•Transformation products of octocrylene are typically more persistent.