Estudo hidroquímico das áreas úmidas na porção noroeste da Bacia do Rio Claro (Uberaba, MG)
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Data
2019-05-23
Autores
Quirino, Raquel Curtolo [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
As áreas úmidas são caracterizadas como ecossistemas da interface entre o ambiente terrestre e aquático, influenciada por inundações permanentes ou periódicas, possuindo floras e faunas típicas adaptadas a sua dinâmica hídrica distinta. Configuram como um dos ecossistemas mais frágeis e ameaçados do mundo, que devido a sua heterogeneidade e a falta de padrões específicos dificulta a criação e adoção de políticas públicas efetivas para a manutenção e conservação dessas áreas. A chapada sedimentar no Oeste de Minas Gerais abriga um importante sistema de áreas úmidas, que são essenciais na manutenção e no equilíbrio hídrico da região, atuando como área de recarga para os córregos, rios e aquíferos existentes. A ocorrência dessas áreas está associada a presença de dois níveis freáticos, sendo um superficial e outro profundo, alimentado pelo primeiro nos períodos de estiagem, relacionados com a arquitetura pedológica da região. O substrato consiste em um sistema latossolo-gleissolo, onde as áreas hidromorfizadas deprimidas topograficamente exibem um importante indicativo para a presença de argilas altamente aluminosas, explorada economicamente na região. Análises hidroquímicas foram realizadas a fim de determinar a composição das águas nessas áreas úmidas, além da observação de possíveis impactos relacionados às intensivas atividades agrícolas na área, a partir das concentrações de elementos traços presentes. A região apresentou um pH neutro, com grande variação nos valores de condutividade elétrica, relacionados às diferentes concentrações iônicas nos pontos amostrados. De maneira geral as águas foram classificadas em bicarbonatadas sódicas, influenciadas pela transformação do gás carbônico em bicarbonato, e pela baixa concentração dos cátions. As águas apresentaram certa semelhança com a composição pluvial, principalmente nos teores aniônicos, evidenciando a contribuição da chuva nas áreas úmidas. Fato que não ocorreu nos dados relacionados aos elementos traços, cujo enriquecimento no sistema ocorre por meio das trocas e complexações no solo e na solução de solo, alinhado principalmente a redução dos hidróxidos de ferro e manganês, típicos processos de ocorrência em áreas hidromorfizadas. Em relação à qualidade das águas, a maior parte dos pontos amostrados enquadrou-se nas diretrizes e parâmetros estabelecidos pelas legislações brasileiras e pela OMS.
The wetlands are characterized as ecosystems of the interface between terrestrial and aquatic environment, affected by permanent or periodic waterlogging, presenting typical flora and fauna, adapted to its distinct hydric dynamics. They represent one of the most fragile and endangered ecosystems of the world, which due its heterogeneity and absence of specific standards hinders the creation and implementation of effective public policies for preservation and conservation of these areas. The sedimentary plateau in Western Minas Gerais holds an important wetland system that is essential in the maintenance and hydric equilibrium of the region, acting as a recharge zone for present creeks, rivers and aquifers. The existence of these areas is associated to the presence of two groundwater levels, one superficial and the other deep, supplied by the first during drought season, related to the site pedological architecture. The substratum consists in a latosol-gleysol system, where the hidromorphized areas, topographically depressed, exhibit a leading indicator for the existence of highly aluminous clays, economically exploited in the area. Hydrochemical analysis were conducted to determine water composition in these wetlands, as well as monitoring the possible impacts related to the intensive agricultural activities in the area, from the trace element concentration. The studied region showed neutral pH, with great variation in the values of electrical conductivity, relative to the different ionic concentration in the sampled sites. Broadly the water was classified as sodium bicarbonated, influenced by the transformation of carbonic gas into bicarbonate and by the low concentration of cations. The waters presented certain similarity to the pluvial composition, especially in the anionic values, evidencing rainwater contribution in the wetlands. The same could not be said for the data related to trace elements, which enhances in the system by exchanges and complexation in the soil and in the soil solution, mostly aligned to reduction of the iron and manganese hydroxides, typical processes of hydromorphic areas. Regarding water quality, most of the sampled locations adhere to the guidelines and parameters established by Brazilian legislation and by WHO.
The wetlands are characterized as ecosystems of the interface between terrestrial and aquatic environment, affected by permanent or periodic waterlogging, presenting typical flora and fauna, adapted to its distinct hydric dynamics. They represent one of the most fragile and endangered ecosystems of the world, which due its heterogeneity and absence of specific standards hinders the creation and implementation of effective public policies for preservation and conservation of these areas. The sedimentary plateau in Western Minas Gerais holds an important wetland system that is essential in the maintenance and hydric equilibrium of the region, acting as a recharge zone for present creeks, rivers and aquifers. The existence of these areas is associated to the presence of two groundwater levels, one superficial and the other deep, supplied by the first during drought season, related to the site pedological architecture. The substratum consists in a latosol-gleysol system, where the hidromorphized areas, topographically depressed, exhibit a leading indicator for the existence of highly aluminous clays, economically exploited in the area. Hydrochemical analysis were conducted to determine water composition in these wetlands, as well as monitoring the possible impacts related to the intensive agricultural activities in the area, from the trace element concentration. The studied region showed neutral pH, with great variation in the values of electrical conductivity, relative to the different ionic concentration in the sampled sites. Broadly the water was classified as sodium bicarbonated, influenced by the transformation of carbonic gas into bicarbonate and by the low concentration of cations. The waters presented certain similarity to the pluvial composition, especially in the anionic values, evidencing rainwater contribution in the wetlands. The same could not be said for the data related to trace elements, which enhances in the system by exchanges and complexation in the soil and in the soil solution, mostly aligned to reduction of the iron and manganese hydroxides, typical processes of hydromorphic areas. Regarding water quality, most of the sampled locations adhere to the guidelines and parameters established by Brazilian legislation and by WHO.
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Palavras-chave
Área úmida, Hidroquímica, Uberaba, Wetland, Hydrochemistry, Brazil