Ecotoxicological effects of microplastics and pesticides, isolated and in mixture, on the native species Chironomus sancticaroli (Diptera) in freshwater aquatic ecosystems

• Grant number: 24/08039-8
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: October 01, 2024
• End date: September 30, 2026
• Field of knowledge: Biological Sciences - Ecology - Applied Ecology
• Principal Investigator: Evaldo Luiz Gaeta Espindola
• Grantee: Diego Ferreira Gomes
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 22/12104-4 - Fate and impacts of microplastics and pesticides in aquatic and terrestrial matrices in agricultural contexts, AP.TEM

Abstract

The occurrence of microplastics (MPs) in freshwater ecosystems, associated with pesticides from point and diffuse sources, has been described as a new concern in the agricultural scenario, as the ecotoxicological effects of this interaction are still unknown. Given this scenario, this proposal aims to assess the effects resulting from the interaction between MP particles and the pesticides imidacloprid (insecticide) and tebuconazole (fungicide), both individually and in mixture, on the invertebrate Chironomus sancticaroli, a representative species of the benthic community. The experiments will be conducted under laboratory and semi-field (mesocosm) conditions, evaluating acute (mortality) and chronic (survival, growth, biomass, and mentum deformities), as well as the analysis of different biomarkers of neurological effect, stress, and oxidative damage. In the laboratory, the species will be subjected to toxicity tests with different concentrations of pesticides and MPs, individually and in mixture, determining LC50, NOEC, and LOEC. Subsequently, toxicity tests with MPs and pesticide mixtures will be performed. In the mesocosms (1,500L water tanks), the same contaminants will be used, considering pesticides individually and in mixture with MP, with organisms exposed in test chambers within each experimental unit, assessing effects before and after contamination, at different time intervals. Besides, water and sediment samples will be taken for toxicity tests under controlled conditions. These samples will be analyzed for their physical and chemical characteristics, which will enable the realization of an Environmental Risk Assessment (ARA) in conjunction with toxicity tests. The results of this study have the potential to deepen understanding of the ecotoxicological effects resulting from the interaction between MPs and pesticides on aquatic organisms.