Caracterização física, química e mineralógica dos sedimentos do baixo rio doce, após o rompimento da barragem de Fundão/MG
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Data
2023-12-15
Autores
Martins, Marx Engel
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Universidade Federal do Espírito Santo
Resumo
The collapse of the Fundão dam in the municipality of Mariana, Minas Gerais, dumped a load of approximately 50 million m³ of iron mining waste into the Gualaxo do Norte River, a tributary of the Doce River, which received and continues to receive this material. Several dams along its course have held back some of the sediment in their reservoirs, but this material is still in the Rio Doce and continues to reach the Atlantic Ocean at its mouth in Regência, a district of Linhares-ES, especially during the summer, which is the period of highest flow. In this context, this work aims to characterize the waste from the dam and deposited in the river, as well as to verify changes in the geochemical aspects of river sediments in the short term, thus determining the degree of interaction between the sediments in situ and the waste. With this in mind, the grain size of the sediment and waste was determined by sieving and sedigraphy, respectively, as well as the morphology of the grains present by scanning electron microscopy (SEM). The chemical composition was determined using X-ray fluorescence (XRF) and the mineralogy of the sand, silt and clay fractions using X-ray diffractometry (XRD). SEM imaging of the sediments shows granular morphologies commonly found in fluvial sediments, such as rounded shapes and a high degree of reworking of the grains, while in the residues there are grains of laminar habit with associated microaggregates. The river sediments showed a large increase in the amount of silicon, while aluminum and iron decreased in proportion to previous studies, while the residues showed an increase in silicon content, and a decrease in iron and aluminum, which are the main components.
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Mineração de ferro , Geoquímica ambiental , Sedimentologia , Resíduos , Waste , Iron mining , Sedimentology , Environmental geochemistry , Fundão, Barragem de (MG) , Doce, Rio, Bacia (MG e ES)