Distribution of chemical elements in estuarine soils contaminated with mine tailings: a non-specific extraction system and chemometric procedures

• Grant number: 23/03756-0
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: September 01, 2023
• End date: August 31, 2024
• Field of knowledge: Physical Sciences and Mathematics - Geosciences
• Principal Investigator: Tiago Osório Ferreira
• Grantee: Alexys Giorgia Friol Boim
• Supervisor: Joanna Wragg
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Institution abroad: British Geological Survey (BGS), England
• Associated to the scholarship: 20/12823-5 - The impacts of Fe mine tailings in the oral bioaccessibility of potentially toxic elements: a study case on the world's largest mining disaster, BP.PD

Abstract

The chemical composition of the soil of the Rio Doce estuary was affected after the input of Fe-rich tailing from the Fundão dam burst in 2015. Since then, studies have been carried out on the role of Fe oxyhydroxides on the dynamics and bioavailability of potentially toxic elements (PTE) under a redox-active environment. The solid phase distribution of Fe and PTE has been determined using sequential extraction methods, but the information provided by these methods depends on the extraction response of the target phase to a given reagent, among other limitations. The use of the Chemometric Identification of Substrates and Element Distributions (CISED) methodology is proposed in this project as an alternative to the traditional sequential extraction methods. The method uses increasing concentrations of aqua regia to the solid matrix and the resulting data from each extraction are submitted to a chemometric mixture resolution algorithm to determine the number and composition of physical-chemical components in the soil. Although it has been well used in studies with different types of solid environmental matrices, the CISED method remains unexplored in the context of hydromorphic soils. In addition, there are also no works in the literature with the application of a chemometric analysis on data obtained from the traditional sequential extraction method for hydromorphic soils. Therefore, the objective is to evaluate the geochemical fractionation of Fe and PTE in soils from the Rio Doce estuary collected in 2021, 6 years after the Fundão dam collapse in Mariana, MG. Data obtained from the traditional sequential extraction for hydromorphic soils and the non-selective CISED extraction will be subject to a self-modelling mixture resolution algorithm (SMMR) and compared. (AU)