Avaliação da qualidade da água do rio Formoso, Buritizeiro, MG

Abstract

The present study evaluated the seasonal monitoring of the water quality of the Formoso River, located in Buritizeiro, Northern Minas Gerais, through the analysis of physical, chemical, and biological parameters. Descriptive statistics were used, including the Mann-Whitney and Kruskal-Wallis tests. Pearson correlation analysis and Canonical Correlation Analysis (CCA) were also performed. Additionally, the percentage of parameter violations in relation to Normative Deliberation nº 08/2022 and the Water Quality Index of the National Sanitation Foundation (WQI-NSF) were calculated to assess the suitability of the water quality for different treatment levels. Samples were collected from seven monitoring stations, covering eleven variables: water temperature (Twater°C), dissolved oxygen (DO), Escherichia coli (E. coli), biochemical oxygen demand (BOD), nitrate (NO3 -), phosphate (PO4 3-), chloride (Cl⁻), turbidity (Turb), total solids (TS), and chlorophyll-α (Chl/α). Results compared to Normative Deliberation nº 08/2022 revealed significant differences between the rainy and dry periods for eight variables. In the violation analysis, seven parameters showed violations of the established limits: Escherichia coli, dissolved oxygen, biochemical oxygen demand, pH, total phosphorus, turbidity, and total solids. The WQI indicated a predominance of water with good quality (Good WQI) during the monitoring period. CCA demonstrated that the first two canonical variable axes explained more than 95% of the variability in water quality. In the rainy season, variables related to organic, microbiological, and physicochemical pollution were highlighted. In the dry season, variables associated with the self-purification process were evident. It is emphasized that the water quality of the Formoso River can be improved through the restoration of riparian zones and the implementation of soil conservation practices, based on edaphoclimatic aspects and vegetation data obtained using Geographic Information Systems (GIS)