Hydrogeochemical and isotopic characterisation of groundwater in a sand-dune phreatic aquifer in the northeastern coast of the province of Buenos Aires. Argentina.

CARRETERO SILVINA; DAPEÑA CRISTINA; KRUSE EDUARDO

ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES

TAYLOR & FRANCIS LTD

Lugar: Londres; Año: 2013 vol. 49 p. 399 - 419

1025-6016

This contribution presents the hydrochemical and isotopic characterisation of the phreatic aquifer located in the Partido de la Costa, province of Buenos Aires, Argentina. In the sand-dune barrier geomorphological environment, groundwater is mainly a low-salinity Ca-HCO3 and Na- HCO3 type, being in general suitable for drinking water; whereas in the continental plain (silty clay sediments), groundwater is Na-Cl type with high salinity and unsuitable for human consumption. The general isotopic composition of the area ranges from -6.8 per thousand to -4.3 per thousand for Delta-oxigen-18 and from -39 per thousand to -21 per thousand for Delta-deuterium, showing that rainwater rapidly infiltrates into the sandy substrate and reaches the water table almost without significant modification in its isotopic composition. These analyses, combined with other chemical parameters, made it possible to corroborate that, in the eastern area of the phreatic aquifer there is no contamination from marine salt water.