Identificação dos corpos dágua mais impactados das bacias dos rios Piracicaba e Paraopeba e cálculo do risco relativo de violação aos limites preconizados pela legislação ambiental

Abstract

This research used multivariate statistical techniques to evaluate the quality of the surface waters of the Piracicaba river basin and the Paraopeba river basin and a risk analysis related to the water bodies of the basins violate the legal limits recommended in the COPAM / CERH-MG 01/2008 in order to compare the two basins. The Cluster and Factorial Analysis, associated to non - parametric tests, allowed the identification of the more degraded water bodies of the Piracicaba and Paraopeba River basins. The parameters microbiological indicator, total manganese and dissolved iron are the most relevant for the characterization of the quality of the basins and Peixe river in Nova Era and Pedras stream in Betim were considered as most affected in the basin The Piracicaba River and the Paraopeba River, respectively. The analysis of violations and the use of relative risk confirmed the impacts that both basins suffer because of economic activities. When compared using relative risk, the Paraopeba river basin presents the highest risk for the parameter of dissolved aluminum, total lead, true color, BOD, total manganese, total suspended solids and turbidity meanwhile the basin of the Piracicaba river presents highest risk for dissolved copper and biological indicator. The release of domestic sewage and industrial effluents, mineral activities and diffuse pollution by agriculture and pasture areas were responsible for the deterioration of surface water quality in these basins. Therefore, investments in basic sanitation, improvement in the efficiency of the treatment of industrial effluents, proper management of soil, preservation of marginal vegetation and environmental education actions are required