Water quality assessment of Pita river (Ecuador), implications for aquatic life preservation

Abstract

The present study corresponds to the evaluation of the water quality of the Pita river and its affluents located inside and outside the Cotopaxi National Park. Seven monitoring stations were set up, in which samples were collected upstream and downstream of each tributary, on April 2018 and April 2019. Physical-chemical parameters were measured in situ such as: pH, temperature and percentage of dissolved oxygen saturation (OD); the parameters established in the Ecuadorian environmental regulations were analyzed: Unified Text of the Secondary Legislation of the Ministry of the Environment, TULSMA, Annex 1, BookVI, table 2, applying methods of analysis according to the Standard Methods for the Examination of Water and Wastewater (APHA). The results indicate that the collected samples exceed the permissible limit for phenols (0.001 mg·dm-3) established in the TULSMA, with the exception of the Hualpaloma river, while for the case of iron, all the samples of the Pita riverbed and its affluents exceed the permissible limit (0.3 mg·dm-3). From the results obtained, the samples collected from the Pita river meet the water quality criteria established for the conservation of aquatic and wild life, despite crossing urban areas, where there are daily domestic and industrial discharges because it is an open channel. Finally, according to the Quality Index applied (ICA-NSF), the affluents located within the Cotopaxi National Park presented a “good quality”, while the affluents located outside the National Park presented an “average quality” related to the proximity to urban areas.