SORPTION AND DESORPTION PROCESS OF S-METOLACHLOR AND HEXAZINONE IN SOILS MODIFIED WITH AGED MICROPLASTICS

• Grant number: 25/06446-8
• Support Opportunities: Scholarships in Brazil - Master
• Start date: June 01, 2025
• End date: May 31, 2027
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Kassio Ferreira Mendes
• Grantee: Carlos Humberto Trujillo Samboni
• Host Institution: Centro de Energia Nuclear na Agricultura (CENA). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated research grant: 24/08299-0 - TRACEABILITY OF MICROPLASTICS IN AGRICULTURAL SOILS AND INTERACTIONS WITH RESIDUAL HERBICIDES, AP.R

Abstract

This project will investigate how the presence of aged microplastics in soils affects the sorption (retention) and desorption (release) processes of two herbicides, S-metolachlor and hexazinone. The soil will be collected from a non-agricultural area with no history of herbicide use, amended with 10% aged microplastics, and tested for its capacity to sorb and release these herbicides. The herbicides will be prepared at different concentrations and added to the soil following a batch equilibrium method. After shaking and centrifugation, the samples will be analyzed by high-performance liquid chromatography (HPLC) to quantify the amount of herbicide sorbed and desorbed. The data obtained will be fitted to linear and Freundlich isotherm models to understand the sorption and desorption behavior. The hysteresis coefficient (H) will also be calculated to measure the difference between the sorption and desorption processes. The aim of this project is to understand how aged microplastics alter the behavior of herbicides in soil. (AU)