Ecotoxicological effects of the insecticide imidacloprid and the fungicide tebuconazole on the native species Allonais chelata (Oligochaeta) exposed in laboratory and mesocosms

• Grant number: 25/00115-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2025
• End date: March 31, 2026
• Field of knowledge: Biological Sciences - Ecology - Applied Ecology
• Principal Investigator: Diego Ferreira Gomes
• Grantee: Giovane Gomes Ferreira
• 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

Pesticides pose a significant threat to aquatic ecosystems due to their persistence and widespread use in agricultural areas, reaching these environments in various ways, resulting in adverse effects on non-target organisms. Given this scenario, ecotoxicological studies are often carried out to specifically analyze how pesticides of various categories, isolated or in mixtures, impact numerous aquatic species. Thus, the main objective of this proposal is to evaluate the effects of exposure to the pesticides Tebuconazole and Imidacloprid, isolated and in mixtures, on the native species Allonais chelata, exposed in the laboratory and mecososms, mainly evaluating the endpoints: survival, biomass (growth) and reproduction. The experiments will be conducted in laboratory and semi-field conditions (mesocosms), evaluating acute (mortality) and chronic (survival, growth and biomass) effects. In the laboratory, the species will be subjected to toxicity tests with different concentrations of pesticides, determining LC50, CEO and CENO. In the mesocosms (1,500L tanks), the same contaminants will be used, considering the isolated pesticides, and the organisms will be exposed in test chambers within each experimental unit, with evaluation of the effects before and after the application of contaminants, in different units of time. In the experimental units, water and sediment samples will be collected to carry out toxicity tests under controlled conditions. The results of this study have the potential to deepen the understanding of the ecotoxicological effects resulting from the interaction between pesticides and native aquatic species.