DEGEO - Departamento de Geologia

URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/8

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Autor: search.filters.author.Galvão, Paulo Henrique FerreiraAssunto: search.filters.subject.São Miguel watershed

Resultados da Pesquisa

Agora exibindo 1 - 2 de 2
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    Cadmium behavior in a karst environment hydrological cycle.
    (2020) Lucon, Thiago Nogueira; Costa, Adivane Terezinha; Galvão, Paulo Henrique Ferreira; Leite, Mariangela Garcia Praça
    Karst regions are important water providers, supplying approximately 25% of the world population. These areas present higher vulnerability to contamination due to hydrodynamics, which hampers the natural depuration of these waters until reaching the underground environment. High concentrations of cadmium (Cd) are observed in the São Miguel watershed, state of Minas Gerais, Brazil. This toxic element is generally and predominantly released into the atmosphere by burning materials that have Cd in their composition, potentially contaminating surface and groundwater. Therefore, the objective of the study is to map Cd concentrations in the hydrological cycle of the São Miguel karst watershed and, through natural background level values (NBL 90%) of rainwater, surface water and groundwater, to understand the seasonal behavior of this element, and to identify the most vulnerable areas to contamination. To achieve this goal, rainwater, surface, and groundwater seasonal monitoring were conducted in 87 sampling stations. A total of 335 samples were collected, distributed over a watershed area of 520 km2 . Concentrations of cadmium above 1 μg/L were found in 21.49% of samples during the rainy season. The origin and distribution of Cd were related to rainfall. For rainwater samples, 90% presented Cd concentration of 3.06 μg/L. When these waters precipitate, they contaminate surface waters (NBL 90% = 1.50 μg/L) and groundwater (NBL 90% = 2.81 μg/L). This study presented a hydrochemical cycle map and proposed NBL values of Cd for surface water and groundwater, helping to understand how the environment is contaminated by this element.
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    Natural background levels and seasonal influence on groundwater chemistry of the Upper São Francisco karst region, MG, Brazil.
    (2018) Lucon, Thiago Nogueira; Costa, Adivane Terezinha; Galvão, Paulo Henrique Ferreira
    Karst aquifers are large water reservoirs that supply approximately 25% of the world population. They are also extremely sensitive to contamination, demanding knowledge on groundwater quality regarding base level conditions for the main cations and anions. Knowing the Natural Background Level (NBL) values of these waters becomes an indispensable measure to understand aquifers and hydrochemical anomalies, either from anthropogenic or geogenic origin. This paper aimed to provide a hydrochemical characterization and to propose NBL 90% values for the little-studied groundwater of the São Miguel River watershed, Upper São Francisco River, MG, Brazil. NBL 90% values were estimated using statistical analyses followed by an analysis of seasonal influence on observed concentrations. The water was classified as calcium bicarbonate, with the highest NBL 90% values occurring during the rainy season for Ca2+, K+, HCO3 -, SO4 2-, Cl-, NO3 -, and As3+. On the other hand, Mg2+, Na+, PO4 3-, and Zn2+ presented reduction in concentration during this season. Nitrate, phosphate and chloride anomalies (values above NBL 90%) are directly related to human action. Thus, monitoring and proposing NBL 90% values were an essential tool to help in understanding the hydrochemical behavior of waters in this watershed.