Probabilistic analysis of the occurrence of incompatibility of the water quality with the legal framework of aquatic systems - case study of Pariquera-Acu River (SP, Brazil)

Although relatively common in Brazil, water quality monitoring programs usually do not organize the results in a way that they are able to guide local authorities for reclamation of aquatic systems. Therefore, this research aimed to discuss the use of probabilistic curves of water quality incompatibility with Brazilian legal framework of water bodies as a complementary tool for monitoring. The incompatibility probabilities with CONAMA 357/05 (framework for Class 2) for Pariquera-Acu river (Sao Paulo, Brazil) were 35, 8, 44, 1, 0, 0 and 0%, respectively, for dissolved oxygen, turbidity, phosphorus, nitrogen-ammonia, nitrite, nitrate and chlorophyll-a. We concluded that the condensation level of information achieved by probabilistic curves represents an important contribution for management of quality of the water.