MONITORAMENTO DA QUALIDADE DA ÁGUA E AVALIAÇÃO DA CAPACIDADE DE AUTODEPURAÇÃO DO RIO LIGEIRO NO MUNICÍPIO E PATO BRANCO - PR

The objective of this study was to monitor the water quality and evaluate the self-purification capacity of the Ligeiro River, from one of the sources to the confluence with the Chopim River. Six monitoring points (PM01 to PM06) were established along the route. Water samples were collected in the different seasons of the year 2017 for analysis of dissolved oxygen (DO), biochemical oxygen demand (BOD) and temperature determination. In addition, hydrological measurements were performed on all PMs. Based on the results of the laboratory analysis, the calibration of the QUAL-UFMG model was carried out for the evaluation of the self-purification capacity. The water quality modeling, in the winter season, presented the highest degree of water quality deterioration, with low OD levels and high BOD concentration, indicating that in the dry season the dilution capacity is reduced to effluent discharges. It is concluded that the Ligeiro River has deteriorated from the source and that its capacity of self-purification presents critical conditions in the period of lower flow.