Toxicity Evaluation of Pesticide Mixtures Through Oxidative Stress and Genotoxic Damage in Palaemon argentinus

GONZALEZ, M. F; BERTRAND, LIDWINA; AMÉ, MARÍA VALERIA

Montevideo

Congreso; Society of Environmental Toxicology and Chemistry (SETAC) Latin America 15th Biennial Meeting; 2023

SETAC LA

Aquatic organisms are exposed to multiple stressors, including the insecticide chlorantraniliprole (C), the fungicide epoxiconazole (E), and the herbicide metolachlor (M), which enter water bodies by drift or runoff. The risk associated with exposure to complex mixtures may be underestimated if only the individual toxicity of each of the stressors is taken into account without considering the possible interactions between them. The aim of this work was to expose the native decapod, Palaemon argentinus, to binary and ternary mixtures of C, E and M under laboratory conditions to evaluate the antioxidant activity through catalase activity (CAT), the oxidative damage through carbonylated proteins content (CP) in cephalothorax and abdomen, and establish genotoxic damage using a DNA damage index (DI) measured by comet assay in the decapod hepatopancreas. Individuals were exposed for 96 h (n=8 (CAT), n=6 (CP), n=15 (DI)) to two environmentally relevant concentration levels, low (LC) and high (HC), in equitoxic units: C: 0.002 and 0.04 μgL-1; E: 1.3 and 26.07 μgL-1; M: 3.5 and 70.5 μgL-1 and a control condition (CTL): 0 μgL-1. The results in cephalothorax showed a significant increase (p<0.05) with respect to CTL, for CAT: C+M at HC; CP: C+E and C+E+M at LC, as well as for the ID: E+M and C+E+M at HC. In addition, significant differences (p<0.05) were observed for CAT in C+M between HC and LC. The results in abdomen at LC presented a significant increase (p<0.05) with respect to the CTL for CAT: C+E and CP: E+M and C+E+M, and a significant decrease was observed at HC (p<0.05) with respect to the CTL for CP: C+E, E+M, C+E+M. In addition, significant differences (p<0.05) were observed for CAT between C+E and E+M at HC and LC. CAT was not affected by the LC and HC mixtures, with the exception of C+M (HC) and C+E (LC), suggesting an underlying mechanism for energy saving at the expense of protein and DNA structural and functional damage. Depending on the combination of pesticides, CP increased at LC, while the DI increased at HC, which can be related to a higher protection barrier for DNA.The interactions in the mixtures that showed the highest frequency at LC and HC were antagonism and potentiation, followed by additivity. These findings highlight the value of further research into the toxic effects of stressor complex mixtures on native aquatic organism when present at environmental concentrations.