Comprehensive water quality assessment of surface sources in the city of Latacunga and the canton Pedro Vicente Maldonado in Ecuador

A study of the quality of drinking water sources - surface waters of the river systems of the city of Latacunga and the canton of Pedro Vicente Maldonado, Ecuador, was carried out during 2018 and 2019. The general sanitary water quality index (WQI) was calculated according to Russian methods, the water quality index of the National Sanitation Foundation (NSF-WQI) of the Ecuadorian water quality regulation. Results from parameterizing the water quality, obtained by WQI and NSF-WQI methods and combined into an overall scheme, were used to generate the rating scale for assessing the hydro-ecological status of aquatic ecosystems. When carrying out a qualitative and quantitative analysis of water from river reservoirs, the excess of the threshold limit values of such indicators as the biological oxygen demand and iron was determined. The calculations show that the WQI method and the NSF-WQI method lead to similar results when assessing the water quality of both reservoir of the city of Latacunga and canton of Pedro Vicente Maldonado. According to the WQI method, the hydrological state of the reservoir of the city of Latacunga was characterized in the range of a scale from “Crisis” to “Risk”, while according to the NSF-WQI method the state was assessed as “Risk”. The hydrological state of the reservoir of the canton of Pedro Vicente Maldonado, was assessed as “Risk” by both the WQI method and the NSF-WQI method. Furthermore, in none of the water bodies under study is the environmental “catastrophe” not recorded.