Water quality assessment of the Educandos basin in Manaus, Brazil: use of the water quality index and multivariate statistical techniques.

Abstract

The city of Manaus has undergone an industrialization process that has negatively influenced the wastewater that makes up the urban part of the city. Monitoring water quality parameters and seasonal changes are essential for decision-making for the recovery of the basin's waters. The study evaluated, through the Water Quality Index (WQI) and multivariate statistical techniques, the seasonal and spatial variation in water quality in the Educandos basin, Manaus. The 14 sampling points were selected in the years 2020, 2021 and 2022. The analyzes followed the recommendations of the Stantard Methods for the Examination of Water and Wastewater. The IQA showed that seasonality has not been enough to cause an improvement in water quality. Cluster analysis ranked similar sample points in relation to water quality. The main component showed that turbidity, total solids and biological oxygen demand are the most relevant parameters for PC1, while for PC2 they were Total Coliforms, Total Nitrogen and pH. The multivariate analysis proved to be efficient for monitoring the basin, considering the process of environmental deterioration, resulting from the receipt of waste of mixed domestic and industrial origin.