Microplastics in surface sediments of the Santos (SP) Emissary region for methodological standardization

• Grant number: 24/11457-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2025
• End date: December 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Oceanography
• Principal Investigator: Décio Luis Semensatto Junior
• Grantee: Lívia Ortega Nishiyama
• Host Institution: Instituto de Ciências Ambientais, Químicas e Farmacêuticas (ICAQF). Universidade Federal de São Paulo (UNIFESP). Campus Diadema. Diadema , SP, Brazil

Abstract

Microplastics (MPs) are polymeric particles ranging in size from 0.001 to 5 mm. They are emerging pollutants with significant environmental concerns and have garnered increasing interest from the scientific community, not only due to the impacts they may cause but also as vectors for other chemical pollutants and microbiota. Despite the substantial number of studies, few countries have focused efforts on developing environmental regulations for these pollutants. One of the main challenges lies in the diversity of possible methodological approaches, which results in a lack of standardization in the collection, processing, and analysis of samples. Consequently, studies on MPs often lack direct comparability and reproducibility. Therefore, the aim of this project is to analyze a set of sediment samples to contribute to the joint effort between the Federal University of São Paulo (Unifesp) and the Environmental Company of the State of São Paulo (Cetesb) to standardize methods for analyzing MPs in sediment, enabling the incorporation of these pollutants into the Coastal Monitoring Network already managed by Cetesb. The project will focus on assessing the effects of using single, duplicate, and triplicate samples on quantitative and qualitative results for MPs. As a case study, surface sediment samples from four locations within the influence zone of the Santos Emissary in the Baixada Santista region, collected during Cetesb's regular coastal water monitoring, will be analyzed. Two dimensions of analysis will be considered: (i) each collection point individually, to assess how replicates at one site may influence results; and (ii) between collection points, to evaluate how replicates may affect the comparison between locations. The working hypothesis is that results produced from triplicate samples are significantly different from those obtained from single samples and composite samples (a combination of replicates to form a supposedly representative single sample of the whole set). Ultimately, this project will contribute to the development of environmental monitoring tools and public policies for controlling MPs in the coastal region of the State of São Paulo.