Geochemical and stable isotopic evolution of the Guarani Aquifer System in the state of São Paulo, Brazil

Šráček, Ondra; Hirata, Ricardo

doi:10.1007/s10040-002-0222-8

Cited by 105 publications

(78 citation statements)

References 11 publications

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“…We compared the fluoride concentrations in these regions using nonparametric (19,23,30,31) ET/P groundwater chemistry Na-HCO 3 type of groundwater with elevated pH (19,(32)(33)(34) global database not available a Numbers indicate references. b Dist_Int_fel ) distance from intrusive felsic rocks, Dist-fault ) distance from normal faults, Dist_V_fel ) distance from volcanic felsic rocks, pH_s ) subsoil pH, and ET/P ) evapotranspiration/precipitation.…”

Section: Methodsmentioning

confidence: 99%

Statistical Modeling of Global Geogenic Fluoride Contamination in Groundwaters

Amini¹,

Mueller²,

Abbaspour³

et al. 2008

Environ. Sci. Technol.

423

164

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The use of groundwater with high fluoride concentrations poses a health threat to millions of people around the world. This study aims at providing a global overview of potentially fluoriderich groundwaters by modeling fluoride concentration. A large database of worldwide fluoride concentrations as well as available information on related environmental factors such as soil properties, geological settings, and climatic and topographical information on a global scale have all been used in the model. The modeling approach combines geochemical knowledge with statistical methods to devise a rule-based statistical procedure, which divides the world into 8 different "process regions". For each region a separate predictive model was constructed. The end result is a global probability map of fluoride concentration in the groundwater. Comparisons of the modeled and measured data indicate that 60-70% of the fluoride variation could be explained by the models in six process regions, while in two process regions only 30% of the variation in the measured data was explained. Furthermore, the global probability map corresponded well with fluorotic areas described in the international literature. Although the probability map should not replace fluoride testing, it can give a first indication of possible contamination and thus may support the planning process of new drinking water projects.

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Section: Methodsmentioning

confidence: 99%

Statistical Modeling of Global Geogenic Fluoride Contamination in Groundwaters

Amini¹,

Mueller²,

Abbaspour³

et al. 2008

Environ. Sci. Technol.

423

164

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“…The presence of sediments deposited under wetter conditions is generally associated with fluvial facies. The Botucatu Formation is comprised of well-sorted, very-fine to fine-grained Aeolian sandstones with cross stratifications of medium to great thickness (CAETANO-CHANG, 1997;SRACEK;HIRATA, 2002).…”

Section: Study Areamentioning

confidence: 99%

Analyses of Water Table Depths Variations in an Outcrop Area of the Guarani Aquifer System in Brotas/Sp-Brazil

Manzione

Soldera

Paes³

et al. 2015

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Several factors may influence variations in ground water levels. Some of these factors present static behavior while others present dynamic changes over time. The differences in management operations in agricultural sites, plant development and agricultural practices have direct impact on the unsaturated zone, as the levels of recharge and water tables can respond differently due to local conditions. Different information sources may be used and integrated in a statistical model to reveal the responses of ground water levels under certain conditions. Understanding these processes involves meeting a way of representing correlated variables together to form a new and smaller set of derived variables with minimum loss of information, removing redundancy or duplication. The objective of this study was to analyze the variations in water table depths using information from a groundwater monitoring network in an outcrop area of the Guarani Aquifer System (GAS) in Brotas, São Paulo, Brazil, associated with soil, vegetation and terrain variables, which possibly influence the groundwater dynamics. A factorial analysis was applied to identify the underlying factors which would explain this pattern of correlation within these sets of study variables. The main factors influencing the variations in water table over the monitoring period were as follows: sand particle size, terrain attributes, soil texture, soil and crop management and vegetation. This methodology can be useful for groundwater management, policy making and regulation of soil use in watersheds, and regional studies, for example, maximizing information in data analysis.Keywords: factorial analysis, statistical modeling, recharge, Brazil MANZIONE, R.L.; SOLDERA, B.C.; PAES, C.O.; WENDLAND, E. ANÁLISES DAS VARIAÇÕES DOS NÍVEIS FREÁTICOS EM UMA ÁREA DE AFLORAMENTO DO SISTEMA AQUÍFERO GUARANI EM BROTAS/SP-BRASIL RESUMODiversos fatores influenciam as variações de níveis freáticos. Alguns desses fatores apresentam comportamento estático enquanto outros apresentam mudanças dinâmicas ao longo do tempo. As diferenças nas operações de manejo do solo em áreas agrícolas, desenvolvimento de plantas e práticas agrícolas tem impactos diretos na zona não saturada uma vez que os níveis de recarga

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“…Diversos processos geoquímicos podem ser associados a essa evolução, como dissolução e precipitação de cimento calcífero, dissolução de silicatos, troca iônica e mistura com águas provenientes de unidades subjacentes nas proximidades do eixo central da Bacia do Paraná (Silva 1983, Meng & Maynard 2001, Sracek & Hirata 2002, Bonotto 2006, Gastmans et al 2010.…”

Section: Sistema Aquífero Guaraniunclassified

“…A evolução hidroquímica das águas do SAG, e que imprime a classificação hidroquímica mencionada, foi descrita por inúmeros autores (Silva 1983, Meng & Maynard 2001, Sracek & Hirata 2002, Gastmans et al 2010, Hirata et al 2011, dentre outros) e envolve os processos geoquímicos de troca iô-nica, que explicariam a passagem das águas bicarbonatadas cálcicas para sódicas, seguida pelo aumento das concentrações de cloreto e sulfato, associado à mistura de águas enriquecidas nesses sais advindas de aquíferos sotopostos.…”

Section: Figura 8 -Comparação Entre As Temperaturas Medidas Nos Poçosunclassified

Geotermometria das águas hipertermais do Sistema Aquífero Guarani no estado de São Paulo

Gastmans

Reis

Kiang

2012

Rev. bras. geociênc.

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Revista Brasileira de Geociências 42(Suppl 1): 208-225, dezembro de 2012 208Arquivo digital disponível on-line no site www.sbgeo.org.br ResumoInúmeros geotermômetros vêm sendo utilizados para a determinação das temperaturas esperadas nos reservatórios de águas subterrâneas, sendo a maior parte deles baseada no equilíbrio químico existente entre as águas termais e minerais constituintes do arcabouço do aquífero. Nesse sentido, águas subterrâneas do Sistema Aquífero Guarani com temperaturas acima de 38ºC, classificadas como hipertermais pelo Código de Águas Minerais, tiveram sua composição química avaliada com o objetivo de se determinar as temperaturas esperadas no reservatório com base na utilização de diversos geotermômetros. Essas águas são essencialmente do tipo Na-HCO 3 , passando a Na-HCO 3 -Cl-SO 4 devido ao aumento nas concentrações de sulfato e cloreto. Existe uma boa relação entre a temperatura e a profundidade em que se encontra o aquífero, indicando gradiente geotérmico médio de 27,7ºC/km. Uma faixa na região central da área de estudo apresenta os menores gradientes termais, abaixo de 25ºC/km, enquanto os maiores gradientes estão situados nas porções NE e W da área de estudo. Os geotermômetros de quartzo indicaram temperaturas acima das obtidas nas saídas dos poços, enquanto o geotermômetro de calcedônia avaliado mostrou temperaturas próximas das medidas em campo, com exceção de alguns poços em que os gradientes geotermais são menores. Os geotermômetros baseados no equilíbrio entre Na/K retornaram temperaturas muito distintas das medidas, enquanto o geotermômetro baseado no equilíbrio entre sódio/potássio/cálcio obteve temperaturas próximas às registradas nos poços com temperaturas inferiores a 50ºC, em função do equilíbrio termodinâmico dessas águas com feldspatos. Os geotermômetros apontam para a possibilidade da ocorrência de misturas de águas mais profundas, especialmente nos poços da porção SW da área.Palavras-chave: geotermômetros; hidroquímica; águas subterrâneas; Sistema Aquífero Guarani. Abstract Geothermometry of hyperthermal waters of Guarani Aquifer System of the state of São Paulo -Brazil.Several geothermometers have been employed to determine the expected temperature in the groundwater reservoirs, most part of them based on the chemical equilibrium between thermal groundwaters and minerals which constitute the aquifer framework. Based on this principle, groundwater from Guarani Aquifer System, which presents temperatures upon to 38ºC, classified as hyperthermal by the Brazilian Mineral Water Code, had their chemical composition evaluated with the main purpose to determine the expected temperatures in the reservoir based on the application of several geothermometers. These groundwaters can be classified as Na-HCO 3 type evolving to Na-HCO 3 -Cl-SO 4 type due the increase in sulphate and chloride concentrations. Measured groundwater temperatures show a good correlation with the depth of the aquifer, indicating an average geothermal gradient of 27.7ºC/km. The lowest geothermal gradients, be...

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Geochemical and stable isotopic evolution of the Guarani Aquifer System in the state of São Paulo, Brazil

Cited by 105 publications

References 11 publications

Statistical Modeling of Global Geogenic Fluoride Contamination in Groundwaters

Statistical Modeling of Global Geogenic Fluoride Contamination in Groundwaters

Analyses of Water Table Depths Variations in an Outcrop Area of the Guarani Aquifer System in Brotas/Sp-Brazil

Geotermometria das águas hipertermais do Sistema Aquífero Guarani no estado de São Paulo

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