Avaliação da toxicidade do fotoprotetor 2-etilhexil 4-metoxicinamato em Oreochromis niloticus e Astyanax altiparanae

Abstract

2-Ethylhexyl 4-methoxycinnamate (EHMC) is an organic ultraviolet filter widely used in the formulations of personal care products and industrial products for photoprotection. Due to its heavy use, a significant level of the filter has been detected in the water and biological communities, resulting in concerns about potential ecotoxicological effects. The present study aimed to evaluate the toxicity of EHMC in Oreochromis niloticus and Astyanax altiparanae after 22 days of subchronic exposure. The bioassays with the two species were conducted separately, under similar experimental conditions. The individuals were exposed to three environmentally relevant concentrations of EHMC (100, 500, and 1000 ng·L-1) in a semi-static system with daily renewal of ¾ of the water and the contaminant, for later evaluation of the health of the fish (Fulton’s condition factor – K), genotoxicity (comet assay), mutagenicity (piscine micronucleus test) and biochemical parameters (AchE, GST, CAT, and LPO). At the end of the bioassays, Fulton’s condition factor indicated that the sunscreen did not affect the physiological and nutritional status of the fish. In both species, the comet assay results with erythrocytes and kidney tissue showed that exposure did not cause genotoxic effects. Despite that, EHMC was able to induce the formation of vacuolated nuclear morphological changes in A. altiparanae exposed to the highest concentration studied. Acetylcholinesterase (AchE) and glutathione S-transferase (GST) activity did not show statistically significant differences for the two species studied. The responses of oxidative stress biomarkers show that only in individuals of the species O. Niloticus exposed to higher EHMC concentration, an increase in catalase (CAT) activity was observed; however, this change does not extend to other oxidative stress responses, such as lipoperoxidation (LPO). Thus, it can be concluded that the highest environmental concentration of EHMC studied showed only a potential genotoxic effect on A. altiparanae and alteration in the activity of the antioxidant defense enzyme CAT of O. Niloticus, suggesting that, under these experimental conditions, EHMC was not proved toxic.