Avaliação da vulnerabilidade de solos representativos de Minas Gerais à contaminação por metais pesados, baseada em estudos de adsorção e processos de extração

Abstract

Among the processes used in the assessment of soil vulnerability to contamination by heavy metals, those related to metal adsorption and recovery are of great importance. In the last part of the work, it was proposed a simplified method for the assessment of soil vulnerability to metal contamination and classification according to vulnerability levels. The relationships between maximum adsorption capacity, binding energy, pH, and element distribution in fraction F1 resulted in four classes of vulnerability, namely, very low, low, medium and high. In general, soils classified as highly vulnerable are most probably unsuitable for activities that can incorporate heavy metals into soil, since the metals would be readily available. These soils were classified as highly vulnerable because of their high acidity, low organic matter and oxides, sandy texture, and other properties. In this study, this type of soilwas mostly micaschist, presenting soils developed on quartzites and influenced by soils with source material from tertiary and quaternary roofs associated with Urucuia sandstone (Haplic Cambisol Tb typical dystrophic and Neossol orthic latosol). The soils classified as little vulnerable are located in the regions of Italva and Pedro Leopoldo and developed on limestone, consisting of migmatites associated with charnockitic rocks (Chernosol Argiluvic carbonate saprolite and Haplic Cambisol Eutric latosol Tb). The main distinctive characteristics of these soils were their high clay contents, and high values of pH and maximum adsorption (b) and strength retention (k). Another level of vulnerability wasattributed to weathered soils (Oxisols and Ultisol) in which mostly showed variations in average levels of vulnerability.