Índice de Qualidade de Água (IQA) para ambientes amazônicos usando Estatística Multivariada

Abstract

The present work aimed to propose a WQI for the acidic waters of Manaus using multivariate statistics. A location isolated from large urban centers was chosen to serve as the region's natural background. Monthly water collections were carried out in this stream between January and July 2022 in order to establish naturalness environmental markers. 22 environmental variables were analyzed, and then Principal Component Analysis –PCA was used to establish the most important variables of the data set. The results showed that the variables that stood out the most were Ntotal, Cl-, Na+and electrical conductivity. The PCA also identified a moderate influence of the variables NH4+, K+, PO43-and fecal coliforms on the water composition. Water categories were createdbased on exponential and logarithmic equations that emerged from the measurements taken. Finally, the equations and curves were applied to 12 bodies of water distributed in the urban area of Manaus and demonstrated that 75% of the evaluated samples were in a very poor condition.