Assessment of availability and bioaccessibility of potentially toxic metals in residual soil

• Grant number: 17/15024-3
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: October 27, 2017
• End date: January 26, 2018
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Valéria Guimarães Silvestre Rodrigues
• Grantee: Jéssica Pelinsom Marques
• Supervisor: Eduardo Anselmo Ferreira da Silva
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Institution abroad: Universidade de Aveiro (UA), Portugal
• Associated to the scholarship: 16/17894-2 - Geological and geotechnical characterization of mixtures of residual soil from Eldorado Paulista (SP) with reactive organic materials, BP.MS

Abstract

Adsorption evaluation plays a fundamental role in the study of potentially toxic metals retention by geologic materials. The study of adsorption of Pb, Zn and Cd by natural residual soils and by mixtures of these soils with peat and organic compost is being carried out in the Master Project developed in Brazil. However, only the characterization of the adsorption behaviour and the determination of the total amount of metal that the soil is able to retain don't provide any information about the metal lability, the strength with wich they are retained in the soil and their potential remobilization. This type of information, as well as the metal bioavailability and bioaccessibility, is essential for the understanding of the future impacts that these elements can cause in the environment. It is also known that besides characteristics like clay content, organic matter content and soil pH, mineralogy also influences contaminant retention, including oxides and hydroxides, which may be common in tropical soils and should be studied in more detail. Thus, the research internship (BEPE), in the Department of Geosciences of the University of Aveiro, Portugal, under the guidance of Prof. Dr. Eduardo Anselmo Ferreira da Silva, will enable the realization of an analisys of greater depth of the mineralogy of the soil that has been studied in the master project, mainly with regard to the iron oxides. It will also allow a study concerning the forms of interaction of the adsorbed metals in the soil fractions through sequential extraction procedures, and the evaluation of the bioaccessibility of these metals, through an in vitro procedure. Thereby, this comes as a complement to the understanding of how Pb, Zn and Cd are retained in the soil (these metals were added to the soil in batch equilibrium tests carried out during the master project in Brazil, aiming to evaluate the retention capacity), its potential of remobilization after adsorbed, and the damages that this could come to cause. (AU)