A review of environmental occurrence and toxicity of 2-ethylhexyl salicylate, homomenthyl salicylate and ethylhexyl methoxycinnamate.

2-Ethylhexyl salicylate (EHS), homomenthyl salicylate (HMS), and ethylhexyl methoxycinnamate (EHMC) are three commonly used organic ultraviolet filters (OUVFs) that exhibit environmental persistence and bioaccumulation potential. They are widely distributed in surface water, wastewater, sediment, soil, air, and dust, as well as in organisms. Their concentrations vary significantly across matrices, spatiotemporal scales, and species. In surface water, the concentrations of the three OUVFs are notably higher in industrial and tourist-influenced waters, with the mean concentration of HMS reaching 215.4 ng/L at Waikiki Beach and EHS averaging 203 ng/L along Romania's Black Sea coast. In wastewater, EHMC occurred at hundreds of ng/L in the dissolved phase, while its particulate-phase concentration peaked at 65,500 ng/g. Their atmospheric concentrations are predominantly in the pg/m3 range, with median values reaching hundreds of pg/m3. Moreover, OUVF concentrations in urban soils remain relatively elevated in soils of industrial areas. Their mean bioaccumulation factors (BAFs) were 1432 L/kg for EHS, 21,642 L/kg for HMS, and 447 L/kg for EHMC, with HMS posing the greatest ecological risk. These three OUVFs elicit diverse toxic effects (e.g., endocrine disruption, plant growth inhibition) and exert compound-specific toxicity through five core pathways: the hypothalamic-pituitary-thyroid (HPT) axis, hypothalamic-pituitary-gonadal (HPG) axis, oxidative stress, lipid metabolism, and apoptosis. Their environmental risks show distinct spatiotemporal and species-specific differences, with maximum exposure risk quotients (RQex) of 33 for EHS and 22 for HMS in summer along the western Mediterranean coast. Considerable uncertainties remain regarding their environmental occurrence, toxicological mechanisms and risk assessment. This paper aims to review the pollution characteristics, ecotoxicity and risk profiles of the three compounds to inform future studies and regulatory decision-making.