Qualidade da água na bacia hidrográfica do Rio Tietê na Região Metropolitana de São Paulo – SP

Abstract

The monitoring of surface water quality aims to identify problems and look for solutions to improve quality of life and environmental health. This work aimed to evaluate the water quality in the Tietê River Basin in the metropolitan region of São Paulo (São Paulo state, Brazil). The data were obtained through the Inland Water Quality Report of the State of São Paulo of the Environmental Company of the State of São Paulo. Water samples were collected twice a month during 2018. Eight monitoring points were used located in the metropolitan region of São Paulo, which were identified as: P1 in Biritiba Mirim, P2 in Mogi das Cruzes, P3 downstream of Suzano Sewage Treatment Plant (ETE), P4 in Itaquaquecetuba, P5 in Guarulhos, P6 on the avenue bridge Aricanduva in São Paulo, P7 at Ponte das Bandeiras in São Paulo and P8 at Ponte dos Remédios in São Paulo. Nine variables of water quality were analyzed: dissolved oxygen, thermotolerant coliforms, hydrogenic potential, biochemical oxygen demand, water temperature, total nitrogen, total phosphorus, turbidity and total solids. The results obtained through the Inland Water Quality Report of the State of São Paulo of the Environmental Company of the State of São Paulo were used to calculate the Water Quality Index (AQI) at each monitoring point monthly and annual average. During the year, in points P1 and P2 of the Tietê River, water quality ranged from optimal to acceptable (AQI between 51 and 81). In the other points (P3 to P8) the quality varied between bad and poor (AQI between 13 and 30), which allows to infer that polluting load launched in the Tietê Basin is higher and the state of degradation is in the course located in urbanized regions. The water quality variables evaluated indicate that the study environment influences on anthropic action, represented by the release of domestic and industrial sewage without treatment into the water network of the basin. This requires measures to reduce the deterioration of the river as a result of sewage emissions. In order to the indicators can present results within the standards established by the legislation, they are necessary public policies associated with water management, such as greater investment in basic sanitation, control of sewage disposal in the watershed, and community engagement in water revitalization movements, in order to improve the water quality of the Tietê River and the sustainability of aquatic communities.