Hubert Mathias Peter Roeser

Métodos e técnicas aplicados na avaliação ambiental do aterro da BR-040 da Prefeitura Municipal de Belo Horizonte - MG

This work evaluated the level of heavy metals contamination of a sanitary landfill area in Belo Horizonte, Minas Gerais, Brazil. This landfill is situated at the edge of the BR-040 highway, and is close to the Belo Horizonte-Contagem borderline. Samples of free-of-waste soils and soils covered by urban waste of different ages were analyzed by physical and chemical means. The same analysis was performed on superficial and underground water samples, and leachate samples. The physical analyses included textural, mineralogical, and micro-morphological analyses. Chemical analyses determined the cationic change capacity of the different soils. Several ways of metal retention in the soils were investigated by sequencial extraction procedures in the following fractions: (1) total fraction, (2) exchanged fraction, (3) bound to organic matter fraction, (4) bound to Fe oxides fraction, and (5) bound to Mn oxides fraction using samples from 07 soil profiles, and 02 trenches that were opened in the waste pile. Nine samples were taken, including leachate samples for water analysis. Physical and chemical analyses of the soils allowed the understanding of the mobility of the heavy metals, and their dispersion in the profiles. The sanitary landfill area is essentially composed of young soils of acid pH, and clayey to clayey loamy sandy texture. The mineralogy of these soils is composed by minerals from acid rocks (gneiss) and basic rocks (gabbro and micro gabbro). Kaolinite is the main minerals of the clay fraction. These studies show that the superficial layers of soil retain part of the heavy metals that come from solid waste piles. In addition, superficial and underground waters in the sanitary landfill are contaminated by organic and inorganic compounds.

Estudo mineralógico do sedimento de manguezal da baía de Camamu-Ba

The Camamu Bay, an important fishing, mining and tourist site, is located at the South Coastal Region of the State of Bahia, Brazil. This large water body is surrounded by extensive mangrove forest and has been the object of many geo-environmental studies. The objective of this work is to present partial results of one of these studies, a mineralogical evaluation in the sediments of the Camamu Bays mangrove. This semi-quantitative study showed that in the stations next the mining zone the sediment is rich in quartz, barite and clays, with small percentage of pyrite and jarosite. However, for the majority of the stations, the mineralogy is predominantly: quartz and clays, with a variety of percentages of barite, pyrite and crude gypsum in some stations. The results obtained in this work indicated that, for this studied mangrove, the mineralogical composition of the sediments seems to be intimately related to the geologic processes occurring locally. The processes can be: either weathering processes in situ, or man made processes with posterior carriage; or through mineralogical modifications in situ, resulting from the physical-chemical conditions operating at the environment.

ADSORÇÃO DE As, Cu, Pb E Cr NA AVALIAÇÃO DA CAPACIDADE DE FIXAÇÃO DE METAIS POR RESÍDUO DE MINERADORAS DE FERRO

Two samples of residues from iron mining plants have been investigated for their retention capacity of As, Cu, Cr, and Pb. The sample with the higher content of iron oxides showed the highest capacity to retain metals. The adsorption affinity series changes from Pb>Cu>Cr»As to As>Pb>Cu>Cr or As>Cu>Cr>Pb, depending on the material and the concentration of the initial solution. In the competitive environment, the Pb adsorption decreases and the As, Cu and Cr adsorption increases. Sequential extraction procedures, carried out after adsorption batch experiments, showed that the most important adsorption process occurs in the oxide fraction and that the major part of the absorbed metal is remobilized from exchangeable and oxide fractions.

Application of a Multivariate Exploratory Analysis Technique in the Study of Dissolved Organic Matter and Metal Ions in Waters from the Eastern Quadrilátero Ferrífero, Brazil

Amostras de agua foram coletadas em 10 pontos em trechos do leste do Quadrilatero Ferrifero (QF), que e uma regiao mineira situada no sudeste do Brasil. Os objetivos deste estudo foram encontrar possiveis relacoes entre carbono orgânico dissolvido (COD), metais e outros parâmetros fisico-quimicos medidos utilizando a rede neural de Kohonen como ferramenta para analisar esses dados geoquimicos multivariados na area estudada. As analises fisico-quimicas foram feitas in situ e em laboratorio, onde as concentracoes de COD e varios ions metalicos foram determinadas. A rede de Kohonen permitiu a visualizacao e interpretacao mais amigaveis dos dados, alem de definir relacoes entre eles. Assim, para os dados analisados, foi verificada relacao entre COD e Fe e um possivel efeito da sazonalidade na distribuicao das amostras. Possiveis evidencias litologicas puderam ser detectadas pela analise exploratoria, especialmente se considerados os elementos Ca, Mg, Mn e Sr. Water samples were collected at 10 points in parts of the eastern Quadrilatero Ferrifero (QF), located in a mining region in the southeast of Brazil. The aims of this study were to find possible relationships among dissolved organic carbon (DOC), metals and other parameters measured in the region studied and evaluate the Kohonen neural network as a tool to analyse this geochemical multivariate data set. Physico-chemical analyses were performed in situ and in the laboratory, where concentrations of DOC and a suite of metal ions were determined. The Kohonen neural network allowed an easier visualisation and interpretation of the results and helped to define the relationships among them. In this way, a relationship between DOC and Fe and a possible effect of seasonality on the distribution of the samples were indicated. Signs of lithology were detected in the analyses, especially considering the elements Ca, Mg, Mn and Sr.