ABSTRACT The aim of this study was to evaluate the water quality and identify groups of pollution in the Middle Pomba River through multivariate statistical technique. There were two campaigns from Oct/2008 to Jan/2009 in nine geo-referenced points along the Middle Pomba River including the analysis of 18 variables of water quality. The multivariate statistical technique, through the application of factor analysis/principal component analysis, caused a decrease in the number of variables of water quality, since the best performance of the variables occurred with the inclusion of 15 of the 18 variables. By the use of factor analysis/principal components analysis, it was found that the best behavior of the variables of the water quality of the Middle Pomba River waters was the one composed of three factors, explaining 74.30% of the total variance. Changes in water quality of the Middle Pomba River were defined by a group of nutrients associated with sewage and diffused pollution; for an organic group, caused by untreated sewage in the water stream, and by a group of suspended solids, expressing the process of water erosion in the basin.
multivariate analysis; limnological aspects; factor analysis; principal component analysis; river water quality
