Cyanobacteria and Cyanotoxin in the Billings Reservoir (São Paulo, SP, Brazil)The Billings Complex and the Guarapiranga System are important strategic reservoirs for the city of São Paulo and surrounding areas because the water is used, among other things, for the public water supply. They produce 19,000 liters of water per second and supply water to 5.4 million people. Crude water is transferred from the Taquacetuba branch of the Billings Complex to the Guarapiranga Reservoir to regulate the water level of the reservoir. The objective of this study was to evaluate the water quality in the Taquacetuba branch, focusing on cyanobacteria and cyanotoxins. Surface water samples were collected in February (summer) and July (winter) of 2007. Analyses were conducted of physical, chemical, and biological variables of the water, cyanobacteria richness and density, and the presence of cyanotoxins. The water was classiſed as eutrophic-hypereutrophic. Cyanobacteria blooms were observed in both collection periods. The cyanobacteria bloom was most signiſcant in July, reƀecting lower water transparency and higher levels of total solids, suspended organic matter, chlorophyll-a, and cyanobacteria density in the surface water. Low richness and elevated dominance of the cyanobacteria were found in both periods. Cylindrospermopsis raciborskii was dominant in February, with 352 661.0 cel mL −1 , and Microcystis panniformis was dominant in July, with 1 866 725.0 cel mL −1 . Three variants of microcystin were found in February (MC-RR, MC-LR, MC-YR), as well as saxitoxin. The same variants of microcystin were found in July, but no saxitoxin was detected. Anatoxin-a and cylindropermopsin were not detected in either period. These ſndings are of great concern because the water in the Taquacetuba branch, which is transferred into the Guarapiranga Reservoir, is not treated nor managed. It is recommended that monitoring be intensiſed and more effective measures be taken by the responsible agencies to prevent the process of eutrophication and the consequent development of the cyanobacteria and their toxins.
The large population contingent and the precarious urban planning in the metropolitan region of São Paulo have resulted in uncontrolled growth in areas where springs exist, generating strong pressures on the reservoirs. Concomitantly, a lack of articulation between public and private policy has led to various socio-environmental conflicts in the Billings watershed. This spring, which is responsible for the direct and indirect supply of water to millions of people, represents an enormous challenge for water resource management. In this context, this study aimed to analyze the seasonal limnological conditions of the Billings Complex, in particular the Rio Grande and Taquacetuba branches, and discuss the implications for the management procedure applied in the branches. Physical (water temperature, pH, electrical conductivity, suspended material, organic and inorganic suspended material) chemical (dissolved oxygen, total phosphorus and nitrogen, nitrate, nitrite, ammonium and inorganic phosphorus) and biological (chlorophyll-a) variables of the water were analyzed and the Trophic State Index was calculated. The results indicate a hypertrophic state in the Taquacetuba branch. The Rio Grande branch presented a mesotrophic state which is, however, artificially maintained due to copper sulfate and hydrogen peroxide treatments. The results are also discussed in light of CONAMA Resolution 357/2005. Levels of chlorophyll-a and total phosphorous in the Taquacetuba branch do not conform to the proposed class of use, class I. In this branch, monitoring must be intensified and measures adopted to reduce the level of nutrients in the main body of the Billings complex.
A ação do homem tem provocado mudanças no meio ambiente, sendo a poluição urbana uma das consequências negativas aplicadas nesse ecossistema. Com o desenvolvimento tecnológico, novas perspectivas computacionais afloram para o monitoramento ambiental. Este artigo apresenta pontos chaves da fenomenologia ambiental que podem se beneficiar da evolução promovida pela computação aplicada nos estudos da poluição, assim como realiza um levantamento de pesquisas e tecnologias utilizadas nesse contexto.
Abstract:The Metropolitan Region of São Paulo presents several environmental liabilities, which could to compromise groundwater quality. This scenario demands research and remediation studies, as well as controls on land and groundwater use. One of the most important hydrodynamic parameters used to characterize aquifers is the hydraulic conductivity. This parameter can be obtained by permeability tests like Slug Test, one of the most common methods currently used in contaminated sites investigation, mainly in locations that are characterized with low capacity to groundwater circulation. This paper describes the application of this method, comparing those proposed by Hvorslev (1951) and Bouwer & Rice (1976) and using the software Aquifer Test Pro (version 2010.1) to interpretation of data from different hydrogeological layers of the contaminated site in Santo André-SP. Therefore, were selected 8 shallow wells (up to 7 m deep); and 11 deeper wells (up to 25.8 m deep). Among the 19 wells tested, Slug Test repetition was realized in 8 wells in order to obtain more representative results. The results were similar for both methods and was demonstrated that the soil characterized by landfill had the highest hydraulic conductivity, which average is 4.76 E -06 m.s-1, and the residual soil presented the lower hydraulic conductivity, averaging 9.03 E-07 m.s-1.Keywords: Slug Test. Hydraulic conductivity. Contaminated sites.Resumo: A Região Metropolitana de São Paulo possui inúmeros passivos ambientais que podem vir a comprometer a qualidade das águas subterrâneas. Essa situação demanda estudos de investigação, remediação e controle do uso do solo e da água subterrânea. Um dos parâmetros hidrodinâmicos mais importantes para a caracterização dos aquíferos é a condutividade hidráulica, podendo ser obtida por ensaios de permeabilidade do tipo Slug Test, um dos métodos mais utilizados atualmente na investigação de áreas contaminadas, notadamente naqueles locais caracterizados por baixa capacidade de circulação da água subterrânea. O presente artigo descreve a aplicação desse método, comparando-se aqueles propostos por Hvorslev (1951) e Bouwer & Rice (1976) e utilizando-se o software Aquifer Test Pro (versão 2010.1) para interpretação dos dados obtidos em ensaios de campo, nas diferentes camadas hidrogeológicas em uma área contaminada no município de Sa nto André-SP. Para isso, foram selecionados 8 poços rasos, de até 7 m de profundidade; e 11 poços mais profundos, de até 25,8 m de profundidade. Dentre os 19 poços ensaiados, realizou -se a repetição em 8 visando obter dados mais representativos. Os resultados foram semelhantes para ambos os métodos e demonstraram que o solo caracterizado por aterro apresentou maior condutividade hidráulica, com média de 4,76E -06 m.s-1, e o solo residual com a menor condutividade hidráulica, apresentou valor médio de 9,03E -07 m.s-1.Palavras-chave: Slug Test. Condutividade hidráulica. Área contaminada. _____________________________________________________________________________________ INTRODUÇÃ...
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