Effects of environmentally relevant concentrations of the sunscreen 2-ethylhexyl 4-methoxycinnamate (EHMC) on Oreochromis niloticus and Astyanax altiparanae.

2-Ethylhexyl-4-methoxycinnamate (EHMC), an organic ultraviolet filter used in sunscreens, has been detected in water and living organisms at concentrations on the order of ng⋅L⁻¹. To understand the ecotoxicological effects of EHMC at environmentally relevant concentrations, juvenile fish were separately exposed for 22 days to three concentrations (100, 500, and 1000ng⋅L⁻¹). Health assessment was performed using somatic, genetic, and biochemical biomarkers. At the end of the bioassays, condition factor, genotoxicity, neurotoxicity, and biotransformation did not show significant effects on the species. However, exposure to the highest concentration of EHMC induced an increase in the frequency of vacuolated nuclei in A. altiparanae and an increase in catalase activity in O. niloticus. It is concluded that environmentally relevant concentrations of EHMC, even with low toxicity to the studied species, cause specific toxic effects in the evaluated species, with antioxidant responses (in O. niloticus) and genotoxicity responses (in A. altiparanae), suggesting a specific vulnerability for each species.