DEGEO - Departamento de Geologia
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/8
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Resultados da Pesquisa
Item Arsenic in the groundwater of Ouro Preto (Brazil) : its temporal behavior as influenced by the hydric regime and hydrogeology.(2007) Gonçalves, José Augusto Costa; Lena, Jorge Carvalho de; Paiva, José Fernando de; Nalini Júnior, Hermínio Arias; Pereira, Janice CardosoIn the city of Ouro Preto (MG), water catchment for public supply originates from superficial drainage, springs, old abandoned mines and some driven wells. In the rocks of the region, As is originally found in gold-enriched sulphide-bearing mineral deposits. The weathering process introduces As into the hydrological system by dissolution of this element into the leachate. Measurement of the As content in the groundwater of some catchments was carried out during 1 year and these measurements demonstrated high As content—up to 224 lg L–1 of As(V)—during the rainy season (the maximum concentration limit according to World Health Organization is 10 lg L–1). Lower values were observed during the dry season and in some sampling stations, As was not even detected. The As concentration variability during 1 year shows a strict and direct relationship to seasonal and hydrological conditions. For city authorities, responsible for public water supply, it is necessary to perform a complete inventory of the water sources used and constantly monitor the As content in the water.Item Influência antrópica na geoquímica de água e sedimentos do rio Conceição, Quadrilátero Ferrífero, Minas Gerais, Brasil.(2007) Parra, Ronal Rafael; Roeser, Hubert Mathias Peter; Leite, Mariangela Garcia Praça; Nalini Júnior, Hermínio Arias; Guimarães, A. T. A.; Pereira, Janice Cardoso; Friese, KurtEstudaram-se 52 amostras de água e 50 amostras de sedimentos de fundo, coletadas ao longo do rio Conceição (Município de Santa Bárbara, Minas Gerais, Brasil). Realizou-se um monitoramento hidro-geoquímico sazonal dos parâmetros pH, Eh, condutividade elétrica, sólidos totais dissolvidos, turbidez e alcalinidade. Foram analisadas as concentrações de sulfatos, cloreto, e dos metais pesados na água. As composições químicas e mineralógicas dos sedimentos foram determinadas como também o background Local e o índice de Geoacumulação. Os resultados indicam que as variações na composição da água e dos sedimentos estão relacionadas com a litologia da área, assim como também com atividades antrópicas. A mineração da área é a principal responsável pelas variações nas características físico-químicas da água e pela poluição com elementos pesados como arsênio e chumbo.Item Distribuição, fracionamento e mobilidade de elementos-traço em sedimentos superficiais.(2007) Pereira, Janice Cardoso; Silva, Aline Kelly Guimarães; Nalini Júnior, Hermínio Arias; Silva, Érica Pacheco; Lena, Jorge Carvalho deThe gold and iron mining activities in the Velhas River yield considerable amounts of suspended solids as well as metals to the hydrological system of the region. The risks were assessed by sequential extraction procedures. They were carried out in sediment samples, aiming to evaluate the presence of Co, Cr, Cu, Ni, Zn and As. Although being at high levels in some parts of the river (e.g. As 527 mg g-1 and Cr 475 mg g-1) they are associated with the residual fraction. Mobility factors were also calculated and show that these species are enriched along the river, e.g. for As 0.02 at the spring and 0.33 at the high course of the river.