The Phreatic Aquifer In The Coastal Dunes Of Southwestern Buenos Aires Province, Argentina. Factors Conditioning Groundwater Quality

In the southwest of the province of Buenos Aires, a chain of coastal dunes contains a phreatic aquifer, which is the only source of drinking water in most of the seaside cities. The objective of this study is to analyze the geological, hydrogeological and anthropic activities that affect the quality of groundwater for human consumption, between the cities of Monte Hermoso and Punta Alta. Methodologically, the research is developed based on the study of antecedent information, field recognition, well census, cutting analysis, interpretation of electrical tomography and hydrochemical data. The results relate the quality of the groundwater with the lithological and stratigraphic characteristics of the area, recognizing the natural presence of trace elements such as F, As, Fe and Mn as well as undesirable organoleptic characteristics (smell, color and taste). In addition, the occupation of the land with potentially contaminating anthropic actions (cesspool or absorbent wells, farmyards, open-air dumps, etc.) is observed. This research aims to contribute to hydrogeological knowledge, providing the conceptual basis for the exploitation and management of the aquifer, in an area where water supply is entirely based on the groundwater resource.