Produção de mapas de vulnerabilidade de solos e aqüíferos à contaminação por metais pesados para o estado de Minas Gerais / Production of soils and aquifers vulnerability maps to heavy metals contamination for the State of Minas Gerais, Brazil

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The study of environmental vulnerability to chemicals nowadays is an important tool to make decisions refering to the use, occupation and management of soils and aquifers. In humid tropical systems where the weathered mantle is depth and well developed, the soil reactivity becomes more important than its permeability. In this way, it is being proposed in this work to consider soils vulnerability maps in analysis of final DRASTIC index of aquifer vulnerability. Corrections and improvements were accomplished in the soils vulnerability mapping to heavy metals contamination for the State of Minas Gerais and the aquifers vulnerability mapping were determined using DRASTIC modified by PISCOPO (2001). The mainly changes in the soil vulnerability map were: (1) increasing in registered profiles numbers of 178 for 329 and its latter utilization, generating larger results reliability, (2) changes in the less developed soils analysis methods, like the Leptosols (FAO classification) and (3) unique data base construction of Minas Gerais soils. The results show that soils with high amounts of Fe2O3 presented lowest vulnerabilities. It indicates that this soils oxide fraction were the main responsible for it. These soils concentrate in the south, centre and western of the state in regions called Sul de Minas, Quadrilátero Ferrífero e Triângulo Mineiro. However for aquifers vulnerability, the results show that porous and karts aquifers like Urucuia- Aerado (Cretaceous and Cenozoic), Bauru-Cauiá (Paleozoic) and Bambuí (Proterozoic) systems presented higher vulnerability. In the case of Bambuí aquifer system the results show that areas formed by pelitic and metapelitc rocks possess the lowest vulnerability while areas formed by karts possess the highest vulnerability. The aquifer system Escudo Oriental presented in the east the larger vulnerability due to high recharge associated, the average soils vulnerability to heavy metals contamination and the extremely fractured aquifer media formed by Achean granites and gneisses. In this aquifer system, the smallest vulnerability index were observed in very uneven relief areas, especially Quartizites areas, in Serra do Espinhaço, Serra da da Saudade and Serra da Canastra. The aquifer system Serra-Geral, of the Paleozoic, despite of the extremely fractured basalts, presented the smallest ulnerability index of all state due to extreme soils protection.

ASSUNTO(S)

ciencia do solo proctor densidade relativa relative density Índice hídrico ótimo proctor optimum hydric index

ACESSO AO ARTIGO

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