Estudio isotópico e hidroquímico de precipitación, agua superficial y subterránea de la microcuenca del río chibunga, en variaciones estacionales”

Abstract

The aim of the current research was to carry out an isotopic and hydrochemical study of precipitation, surface water and groundwater of Chibunga River micro-basin in seasonal variations. Twenty-nine samples for parameters related to pH, electrical conductivity (EC), total dissolved solids (TDS), anions and cations were analyzed, as well as 36 samples for oxygen 18 and deuterium, coded according to the sampling location. pH values of 5.65-9.17 in dry season and 5.15-8.33 in rainy season, EC of 41-320 µS/cm in dry season and 3.98-171 µS/cm in rainy season were obtained, while for TDS, values of 9.64 to 678.290 mg/L in dry season and 9.57 to 429.78 mg/L in rainy season were obtained. All these values were within the permissible limits. The Piper plot revealed the prevalence of calcium/magnesium/carbonate ions regarding groundwater and surface water hydrochemistry during the dry season and calcium/magnesium chloride/sulfate ions during the rainy season. On the other hand, the analysis of isotopic concentrations showed that regions near the river recharge reflected a lower abundance of stable isotopes related to the discharge regions, considering C9, C10 and H1 as the most representative points of the recharge zone during the two seasons. It was concluded that variations in hydrochemical concentrations are due to natural or anthropic processes caused by low phreatic levels and the buffering capacity of the water depending on the station. In addition, the recharge water comes from precipitation and snowmelt from the Chimborazo Volcano, which is transported to various points of the micro-basin through the evaporation and infiltration processes. It is proposed to determine the mixing and exchange processes of the Chibunga River micro-basin.