ANÁLISE DA QUALIDADE DA ÁGUA DE RIOS URBANOS NO MUNICÍPIO DE CAXIAS DO SUL-RS UTILIZANDO ESTATÍSTICA MULTIVARIADA

Understanding the evolution of water quality in time and space is an indispensable tool in a world dependent on water in good quality and quantity. In this sense, the study aimed to analyze the water quality in urban rivers in the municipality of Caxias do Sul, using multivariate statistical techniques. Twelve points distributed in the Faxinal, Maestra, Belo, Piaí, and Pinhal sub-basins, in the urban area of the municipality, were analyzed. For water quality analysis, twenty-one physical, chemical, and biological parameters collected in two periods (2012 to 2014 and 2022) were analyzed. The Principal Components Analysis (PCA) identified three components that together explained 63.1% of the data variability. Cluster analysis (AA) separated the analyzed periods into two groups. One of the groups was formed by all the points present in the Tega sub-basin, which is the most urbanized basin in the municipality. The PCA and AA pointed out that the main sources of water quality degradation in the municipality come from the discharge of domestic and industrial effluents into water bodies. This result demonstrates the importance of studies of this nature to support public power in managing water in their territory.