Relationship between water quality parameters and land use of a small Amazonian catchment

The aim of this study was to verify the relationship between water quality parameters and land use in a small Amazonian catchment to evaluate the potential contamination considering seasonality. For this purpose, water samples were collected monthly in the period from April 2015 to October 2017. The variables influencing the water quality of the basin under study were identified through the use of a multivariate statistical analysis—factorial analysis/principal component analysis (FA/PCA). The analysis allowed the selection of three main components that accounted for 64.12% and 64.58% of the total data variation in the rainy and dry periods, respectively. For the rainy season, the three selected principal components (PCs) indicated surface runoff as the main determinant of the variables that compose them, and the organic contribution not associated with rainfall and the strong agricultural activity in the basin were suggestive of the variables of the dry period. It is also possible to observe the influence of the sediment load on the concentrations of nutrients/contaminants in the Prata catchment. This influence can be explained by the predominant type of land use in the small river basin.