CONICET | Buscador de Institutos y Recursos Humanos

La Ballenera lagoon is located in the Interserrana plain in Buenos Aires province, between the towns of Miramar and Mar del Sur. The lagoon is fed and discharged through the creek La Ballenera that finally flows into the Atlantic Ocean. The main objective of this work is obtaining hydrochemical and isotopic lagoon and creek characterization. Then distinguish the component of its flows. Some superficial point on the creek and one point on the lagoon was sampled at four occasions corresponding to each season of the year from 2013 to 2015. Thephysicochemical parameters of electrical conductivity, pH and temperature were determined in situ. The chemical analyzes of major ions, nitrate and fluorine were carried out by standard methods in the laboratory of the Hydrogeology Group of the University of Mar del Plata. The isotopic analyzes were carried out by LASER spectroscopy in the laboratories of the INGEIS and the University of Mar del Plata. The waters of the creek and the lagoon are sodium bicarbonate type with alkaline pH, average electrical conductivity of 1637 μS/cm. The isotopic composition indicates that the contributions to the lagoon are local rainfall, the waters of the La Ballenera stream and the groundwater. During the months of higher temperature, the waters are located along the evaporation line that intersects the local meteoric line at the average point where the groundwater is located, indicating a predominance of groundwater in its composition. The high values of the electrical conductivity, the ionic content and the isotopic composition are explained by a strong geomorphological and hydrogeochemical control.