Monitoramento e modelagem da qualidade da água e agrotóxicos em corpos hídricos no Baixo São Francisco sergipano

• Ano de defesa: 2015
• Autor(a) principal: Britto, Fábio Brandão
• Orientador(a): Aguiar Netto, Antenor de Oliveira
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Sergipe
• Programa de Pós-Graduação: Pós-Graduação em Desenvolvimento e Meio Ambiente
• País: Brasil
• Palavras-chave em Português: Meio ambiente; Controle de qualidade da água; Água; Qualidade da água; Produtos químicos agrícolas; Hidrologia; Agrotóxicos; Modelagem hidrológica
• Palavras-chave em Inglês: SWAT; Pesticide; Rice-growing
• Área do conhecimento CNPq: OUTROS
• Link de acesso: https://ri.ufs.br/handle/riufs/4043

The importance of monitoring studies in areas with man-made actions is related to the diagnosis of environmental impacts in water source regions, in the search of factors that show, in a simple way, the causes for degradation of multiple uses areas. In Sergipe, the presence of several Irrigated Perimeters in the riverbanks justifies the search of these changes. To this end, it was defined the study in the area of floodplains in Betume and in California’s nonirrigated area. It was performed 34 monitoring campagins from March 2013 to December 2014. It was analysed the physical-chemical parameters and turbidity rates, chlorophyll, DO, DBO and thermotolerant coliforms, both during the dry and wet periods, way more than the limits established by CONAMA/2005’s resolution, class 2. Besides the aforementioned water sources, others were attached to the study, among them: Jacaré River, Santo Antônio River, Pilões River, Papagaio River, Capivara River and Jacaré-Curituba Dam. The Water Quality Index (WQI) revealed a tendency of 54% compromising the quality of water of the Rivers mentioned before, due to the domestic effluent. On the other hand, the Trophic State Index (TSI), the compromising reached 82% of the water quality, through eutrophication of water sources. Besides, through multivariate analysis grouping type, it was demonstrated the relationship between the association of physical-chemical parameters. This association happened to Betume River with Santo Antônio River, Pilões River and São Francisco River. Similarly, during dry weather, Onça Creek with Betume's drainage; and Santo Antônio River with Pilões River, and all of them presented proximity. It can also be highlighted that the application of Factor Analysis to the variable group in the selection of three indicative aspects of water quality of the studied rivers. The Varimax rotation of factors showed that the variables of water quality are mainly related to mineral, nutritional, organic matter and degree of pollution content. Another factor was noticed regarding the handling of cultures in the irrigated perimeters which was the use of pesticides in order to control plagues, and to analyse this aspect, it was collected bimestral water, in 12 campaigns. The results detected active principles used in agricultural practices in the irrigated region, among them: chlorpyrifos, atrazine, ivermectin, cyproconazole, tetraconozole and tebuconazole. The rates presented were below the acceptable, when compared to patterns of acceptable daily ingestion (ADI) of ANVISA and EPA. However, according to European Community, the concentrations of tebuconazole and chlorpyrifos were elevated. Based on these results, it was used the SWAT model, an appropriate tool for modelling, which enables generating Scenarios to the use of these pesticides in rice-growing areas. The results demonstrated low mobility in water and the application of constant pesticide in order to fight rice blast showed a high potential of the transported Terbuconazone, when dissolved in water. The presence of chlorpyrifos occurred during rice inter-harvest, in low concentration, when compared to water movements, due to the mobility in water, and low soil retention. Thus, it was evidenced that the man-made actions referring to changes to the use of soil in hydrographical basins promote changes both in production and quality of water as well as the presence of pesticides in sediment and superficial water. These interferences in the habitat should promote public policies that manage systems of water quality monitoring applied to these regions, thus, preserving and protecting the water supply of possible contaminations of environment and inhabitants.