Spatial and Temporal Evaluation of Water Streams Using Quality Indexes: A Case Study

Abstract

The present study aimed to analyze the spatial–temporal variation of water streams using Quality Indexes of the Minas Gerais Institute of Water Management (WQI-IGAM), compared with physical–chemical and biological variables established by the CONAMA Resolution 357/2005 employed for water classification. A water stream in the city of Cachoeira-Alta, State of Goiás, Brazil was used as a case study. Four sampling points along the water course were planned; at each point, the variables of dissolved oxygen (DO), temperature (T) and hydrogen potential (pH) were analyzed, using portable equipment, and samples were collected for laboratory analyses of the variables total phosphorus (TP), biochemical oxygen demand (BOD), total nitrogen (TN), turbidity (Turb), total residues (TR) and thermotolerant coliforms (TC). The waters were classified as of poor quality in relation to the variables TP and TC. The water course was classified as class 3 for the results of TP, class 2 for the results of BOD and TC and class 1 for the results of the other variables, according to CONAMA Resolution 357/2005. It is expected that the watershed management bodies will have a greater concern in the supervision of these resources, requiring greater protection of riparian forests and adequate management of watersheds.

Atlantic Coast water quality in Santa Catarina (Southern Brazil): multivariate analysis and influence of land use and occupation

“…The thermotolerant coliform parameters and total phosphorus were responsible for the greatest variability in Principal Component 3 (F3) (accumulated variability of 70.8%). Thermotolerant coliform is a good indicator of water quality, especially in terms of pollution related to raw sewage disposal from domestic sources or even activities such as cattle and pig farming (Ramalho et al, 2022). In urban areas, the increase in phosphorus concentration in rivers is commonly related to sanitary sewage (Dębska; Rutkowska; Szulc, 2022).…”