Avaliação da qualidade da água do Rio Verde, Ponta Grossa, PR, através de análise multivariada e aplicação de índices de qualidade

Abstract

The objective of this work was to evaluate and interpret the chemical and physical parameters related to the water quality of the Verde River, Ponta Grossa, Paraná State, expressing through the Trophic State Indexes (TSI), Water Quality Index for Protection of Aquatic Life, the Water Quality Index of CETESB (WQI), the Canadian Council of Ministers of the Environment (WQI-CCME) and submitting to the Multivariate Analysis. In this way, it is expected to identify the possible sources and pollutant loads of the surface waters of the Verde river watershed, to evaluate how the applied indices effectively express the impact. Samples were collected at 4 river points for 12 months. There was a tendency for eutrophication indicated by the TSI, with the concentration of phosphorus higher than the limit established by the legislation, which is decisive for this situation. The IQApva indicated "bad" water quality at the point downstream of the Sewage Treatment Station, where the impact is evident, projected by the fact that the effluent void is above the river capacity to receive delivery. The same evaluation was given by WQI-CETESB and WQI-CCME. In points 1 and 2 a water quality is shown as "good" according to WQI-CETESB, but only "marginal" by WQI-CCME. This index classified the water collected in Point 3 as "marginal", which for the WQI-CETESB still had "medium" quality. It was considered in this work that the WQI-CCME expressed in a more real way the state of conservation of the river. Through the multivariate analysis, it was possible to indicate that the impact caused in points 1 and 2 is practically only for the agricultural activities in the surroundings of the river, whereas in points 3 and 4, there is a great influence of the organic matter coming from urban sewage without adequate treatment and by the ETE.