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Physic chemical and microbiological assessment of water quality in Machángara and Monjas rivers from Quito's metropolitan district

Abstract:

This study analyses the current condition of Machángara and Monjas rivers, by evaluating the quality of its waters. Physical and chemical parameters such as: Flow, pH, temperature, dissolved oxygen and ORP were evaluated by in situ monitoring, during the months of August to November 2014. Water samples were also taken for microbiological analysis (total coliforms TC and fecal coliforms FC) in laboratory, using the Multiple Tube Fermentation method, established by the Standard Methods. The analyzes show that both rivers far exceed the permissible limits established in TULSMA for total coliforms, fecal coliforms, temperature, and dissolved oxygen in the case of Monjas River. This prevents their use for wildlife preservation, and agricultural and livestock activities. A considerable increase in the flow of both rivers was also reflected on the results; in addition, the ORP value is in both, less than the 650mV optimum value. The obtained results confirm the poor water quality of the studied rivers, which are an important part of the DMQ's water network and run through areas of high population density, receiving domestic and industrial discharges, daily.