Qualidade das águas superficiais da porção mineira da Bacia do Rio Doce e sua relação com aspectos socioambientais

Abstract

Human activities have degraded the environment in many ways, especially the rivers. Therefore, monitoring surface water quality is indispensable to manage water resources in order to control pollution. The aim of this dissertation was to research monitoring data for surface water quality from a section of the Doce river basin in Minas Gerais, in order to assess water quality parameters, and the influence of environmental and social factors on the basin. Water quality monitoring generates a large amount of data, making it difficult to analyze and interpret, as a result multivariate statistical analyzes are an important support tool for the analysis and interpretation of this data. Cluster analysis and Factor analysis associated with non-parametric tests and violation analysis of the limits prescribed by legislation, identified parameters and the most impacted areas, especially the RD056 station in the city of Caratinga, which is strongly impacted by domestic sewage and agriculture. The dissertation also conducted a social and environmental study of various aspects that can be associated with the water quality data. Aspects such as environmental licensing, sanitation, reducing the flow of major watercourses, floods, economic impacts, extreme events and the impacts on the state of Espírito Santo were discussed. These aspects, with the analysis of the occupation of Doce river basin , highlighting the gold cycle, and the wood cycle that almost extinguished the native forest in the region, provided background to understand the social and environmental variables and their relationship with water quality. The main parameters responsible for the degradation of the basin were fecal coliforms, dissolved iron, total manganese, true color, solids (TSS, TDS, ST), turbidity, dissolved aluminum and total phosphorus. These parameters can be associated with the main problems of the basin, such as sanitation and low percentage of sewage treatment, steel activities and mining activities associated with pollutants such as iron and manganese, as well as extreme events such as dam structural failure. The situation is aggravated by problems related with environmental licensing, particularly in post-licensing. Emphasis should be given to high vulnerability of erosion to the basin, both from the main activities (agriculture and mining), causing deforestation and contributing for sediments in the water course and silting of rivers, consequently causing droughts and floods. So this integrated analysis was of upmost importance to interpret the basin, pointing out the main problems and providing knowledge for solutions.