Caracterización hidrogeoquímica básica en cuatro microcuencas de los distritos mineros: Bella Rica, San Gerardo, Nambija y Chinapintza.

Abstract

This study presents a basic surface water hydrogeochemical description and analysis, in four microwatersheds, in Southern Ecuador. They are located in the provinces of Guayas, Azuay, El Oro and Zamora Chinchipe, corresponding to the mining districts of Bella Rica, San Gerardo, Nambija and Chinapintza. The purpose of this study was to evaluate the water quality of the surface waters and to analyze their suitability as drinking water. For this study, fifty-eight water samples were collected in 2012, 2014 and 2019. Twenty-six were sampled during the rainy season and thirty-two, in the dry season. The physical-chemical analysis of temperature, electrical conductivity and pH indicated that the highest parts of the micro-watershed are characterized by lower temperature, lower electrical conductivity and neutral pH. Downstream of the micro-basin, the ions concentrations, temperature and electrical conductivity, increases. The water quality index (WQI) results for the two seasons (wet and dry), showed that twenty water samples were characterized as “good quality”, twenty-six as “medium quality” and eight as “bad quality". The samples physical-chemical parameters (OD, TDS, turbidity, pH, Ca2+, Mg2+, Na+, K+, Cl-, F- Mn2+, SO42-, NO3- y NO2-) were compared with national and international water quality norms for human consumption and domestic use, such as TULAS (2005) and WHO (2018). The results indicated that the concentrations of Na+, K+, Cl-, F-, are within the maximum permissible limits of water consumption. The water samples collected come from highly mineralized areas where there are anthropic activities such as mining and agriculture. Those are the main reasons for the low water quality in most of the samples, which made them, not suitability for human consumption.