Ecotoxicological Evaluation of Organic Sunscreens Used Worldwide, Alone and in Mixture, on Terrestrial Plants

The environmental hazards of sunscreens are discussed worldwide. However, there are few ecotoxicological studies on these compounds alone for edaphic organisms, and none for their mixtures. Avobenzone (1 and 10 ng/L), octocrylene (10 and 100 μg/L), and oxybenzone (2 and 20 μg/L), alone and in binary combinations (between the lowest and the highest concentrations), were evaluated for phytotoxicity to the roots of rustic varieties of Daucus carota and Solanum lycopersicum, and for cytotoxicity and genotoxicity in the roots of Allium cepa bulbs. In contrast to the higher concentrations, the lower concentrations of sunscreens, despite the increase in superoxide and hydroxyl radicals in the cells, did not cause changes in the length of the rootlets, since they did not affect cell elongation. In mixture, the lower concentrations caused a synergistic interaction in the roots, while the higher did not exceed the toxicity of the filters alone. In bulbs, the filters alone and in mixtures caused inhibition of cell division and mitotic spindle alterations in the meristems, mainly due to the accumulation of H2O2 in the cells, and the mixtures triggered a synergistic interaction in the roots. The mixtures were highly hazardous, especially avobenzone‐oxybenzone, the most absorbed by the roots and with the greatest phytotoxic and cytogenotoxic potential; however, of low environmental stability. Environmentally stable mixtures with octocrylene were the least absorbed but were highly harmful, inducing phytotoxicity and cytogenotoxicity in the plants. Therefore, the use of sewage sludge and wastewater on crop soils poses a risk to agricultural productivity and the environment.