Hidden costs of beauty: An in vitro study on the ecotoxicological impacts of ultraviolet filters and parabens on the bioindicator species Mytilus galloprovincialis.

Skincare is an increasing concern, as ultraviolet (UV) radiation causes skin diseases and photoaging, increasing demand for photoprotective personal care products (PCPs). PCPs contain UV filters, namely ecamsule (ECA), 2-ethylhexyl 4-methoxycinnamate (EHMC) and octocrylene (OC), and parabens, such as propylparaben (PPb) and methylparaben (MPb). These enter the environment, posing toxicity risks to marine species. Ecotoxicity screening of multiple contaminants is resource-intensive, making in vitro alternatives valuable. We assessed the toxicity of these chemicals (0, 50, 500, 5000 ng/L) using S9 subcellular fractions from Mytilus galloprovincialis digestive glands (DG) and gills (G) after acute (30 min) in vitro exposure. Antioxidant enzymes activities decreased after exposure to EHMC and both parabens. OC triggered an increase in glutathione peroxidase activity. Carboxylesterases activity was inhibited in G exposed to EHMC and both parabens, whereas higher ECA concentrations increased the activity in DG. An increase in glutathione-S-transferase activity occurred in G exposed to MPb and the highest PPb concentration. Neurotoxicity occurred in DG exposed to EHMC and ECA, and in G exposed to EHMC, PPb and MPb. EHMC and both parabens elicited the strongest responses in the antioxidant and biotransformation systems, cellular damages and neurotoxicity. This study demonstrates that exposure to environmentally relevant concentrations of cosmetic chemicals may lead to impairments within S9 subcellular fraction, which may compromise mussels' survival.