Multivariate Tool for Biomonitoring of Water Quality: Upper Para?ba River Reservoirs

Factor Analysis is a multivariate statistical tool that considers the effects of multiple factors and aggregates individual measures. The development of this type of study is essential for data from biomonitoring where several variables are monitored with the objective of an environmental diagnosis. This work aimed to use the statistical tool for the treatment of limnological data in order to select factors that determine the water quality. To do so we used the database of limnological monitoring of the upper Paraíba River basin, which consists of 23 variables. The factor analysis showed differences in relation to the percentage of explanation for the three reservoirs, being 75%, 86% and 82% for Camalaú, Cordeiro and Poções, respectively. The variables related to nitrogen (e.g. total nitrogen, ammonia and nitrate) and phosphorus concentrations in the water were considered as the most relevant to explain the data of the environmental matrix in all reservoirs. The factor analysis is an excellent tool for the treatment of limnological data.