Influence of degradation on the toxicity of microplastics to aquatic species: a comparative study between pristine and degraded polyethylene

• Grant number: 24/08669-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2024
• End date: October 31, 2025
• Field of knowledge: Biological Sciences - Ecology - Applied Ecology
• Principal Investigator: Evaldo Luiz Gaeta Espindola
• Grantee: Natália Ruggero Vassalo
• 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

With the increase in population and the need to meet the technological demands of materials in terms of durability and versatility, plastic emerged, currently characterized as one of the most complex environmental problems. For decades, it has been found abundantly in different environmental compartments, compounded by its difficult degradation and long persistence, which enhances negative impacts on biodiversity. In this context, microplastics (MPs) arise from different degradation processes, which can alter not only the size of the particles but also their toxicity. In this study, we will evaluate the toxic effect of pristine and degraded polyethylene MPs through chronic assays with two freshwater species: the oligochaete Allonais chelata and the gastropod Physa acuta. Pristine polyethylene MPs (with a diameter of 34-50 µm) will be photodegraded (constant exposure to UV-C radiation) at two different times. The degree of degradation will be assessed through physical and chemical analyses of the particles. Subsequently, chronic toxicity tests will be conducted with pristine and degraded MPs, evaluating effects on the reproduction and biomass of A. chelata (10-day exposure) and the survival, growth, behavior, and reproduction of P. acuta (14-day exposure). At the end of the experiments, we aim to discuss whether different levels of polyethylene MP degradation alter their toxicity and the potential risks to aquatic species.