Analysis of chemical variables in the water of the Córrego do Galante Watershed – SP

Resumo

Population growth accompanied by inefficiencies in the management of sanitary effluents has been triggering adversities in relation to water quality. In view of the above, this work aims to analyze the concentrations of dissolved oxygen and biochemical oxygen demand in the water of the Córrego do Galante Hydrographic Microbasin - SP. Six strategic points were selected to carry out the research, each with its own characteristic, totaling eight collections of water samples, between the months of December/2021 to July/2022. Taking into account the results of the work, it was necessary to carry out an analysis of two chemical variables, which followed specific methodologies. Regarding the Dissolved Oxygen (DO), it was determined by the spectrophotometry methodology of HANNA Instruments, as for the Biochemical Oxygen Demand (BOD), it followed the method described in the Standard Methods for Examination of Water and Wastewater. The lowest DO concentrations obtained were recorded in the Dec/2021 and Jan/2022 periods. In general, over the period studied, the BOD resulted, for the most part, in values ​​outside the limits established by legislation. The period Feb/2022 for point 1 – east – resulted in a concentration of 181 mg.L⁻¹. It is concluded that the Córrego do Galante Watershed is an example of an environment that has been supporting constant anthropogenic impacts, being able to confirm this state through the OD and BOD variables. Among the negative factors, those that most influence the variations in concentrations are the release of sanitary effluent and urban drainage.