Termoanálises de matéria orgânica e vulnerabilidade à contaminação por metais pesados de solos do estado de Minas Gerais

• Autor(a) principal: Lima, Carlos Eduardo Pacheco
• Data de Publicação: 2010
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1610
• topic: Termodegradação de matéria orgânica; Solos tropicais; Metais pesados; Thermal degradation of organic matter; Tropical soils; Heavy metal; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::CIENCIA DO SOLO

The stability of organic matter and heavy metal pollution are two of the major environmental issues and sustainability of the soil, widely discussed in recent decades. Important issues such as maintenance of soil fertility levels, soil chemical quality, global climate change, among others, are closely linked to them. Although many studies have been conducted focusing on these issues, significant gaps still exist and the elucidation of these is necessary. Thus, they could be used more efficiently in conducting of environmental studies, such as impact assessment and development of diagnostics, or as tools for planning, management, use and occupation of lands. Accordingly, the present study sought to focus the relation between thermal stability of organic matter and physical, chemical and mineralogical aspects of soils of Minas Gerais, and to measure and map their vulnerability to contamination by six heavy metals (Cd, Cr, Cu, Ni, Pb and Zn). The results showed a strong relationship between thermal stability and the presence of oxides. In this sense, for the set of soils, the aluminum oxides (gibbsite) were highlighted. In relation to the vulnerability of soil contamination by heavy metals, the results showed that the clayey Ferralsols were those showing the lowest levels, especially the ferric. Then the clayey Acrisols, for the most part, had average rates for Cu, Pb and Cr and low for Cd, Ni and Zn. The Nitisols showed the same behavior that Acrisols and, ferric ones, showed the lowest rates. Sandy loam and sandy loam soils were always classified as medium or high vulnerability. The Cambisols showed high vulnerability. For Leptosols, Arenosols, Fluvisols and Gleysols were attributed high rates for three reasons: 1) Arenosols due to low retention capacity of soils with predominance of sand fraction, 2) Leptosols due to its small thickness, 3) and Fluvisols and Gleysols due to the constant change in the redox potential which, in turn, may allow the release of metal cations previously retained in the mineral and organic fractions. In addition, six maps, specific for each heavy metal, were also produced for the soils of Minas Gerais state.