Sorption of the insecticide fipronil on polyethylene microplastics: toxicity effects on Chironomus sancticaroli and Daphnia similis

• Grant number: 24/01815-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2024
• End date: January 10, 2025
• Field of knowledge: Engineering - Sanitary Engineering - Water Resources
• Principal Investigator: Evaldo Luiz Gaeta Espindola
• Grantee: Matheus Dias Rezende
• 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 inappropriate production and disposal of plastics, associated with the widespread use of pesticides in the country, can present environmental consequences. Polyethylene and fipronil, respectively, are examples of those contaminants that have already been detected in water bodies and can cause damage to aquatic organisms, especially when combined. Based on this, the current research project aims to study the effects of the sorption of fipronil onto polyethylene microplastics to native freshwater species. For this purpose, the toxic effect of isolated polyethylene microplastics and their combination with fipronil will be assessed in chronic and acute toxicity assays with two representative freshwater species: the insect Chironomus sancticaroli and the microcrustacean Daphnia similis. Therefore, for the assays involving combined contaminants, microplastics contaminated with fipronil samples will be prepared through sorption tests in aqueous solution, considering two concentrations of fipronil (64 and 465 µg L-1) and three concentrations of microplastics (10, 20 and 40 mg L-1). The quantitative assessment will take place through chemical analysis of fipronil solution after the filtration of the submerged microplastics. In this way, it is expected to simulate the conditions of contamination of microplastics by pesticides in the environment, aiming to identify the lethal and sublethal adverse effects of the contaminants on the exposed organisms.