ISÓTOPOS AMBIENTALES EN EL AGUA SUBTERRÁNEA EN EL NORESTE DE LA PROVINCIA DE LA PAMPA, ARGENTINA

CEBALLO LORENA; DAPEÑA, CRISTINA; SCHULZ, CARLOS J.

Actas del XI congreso Argentino de Hidrogeología: agua subterránea, el agua que no se ve

Ediuns

Lugar: Bahia Blanca; Año: 2022; p. 134 - 142

Groundwater in the northeast of the province of La Pampa is the only source of water supply for human consumption and domestic use; therefore, it is essential to know the behavior of the aquifer system. In this work, an isotopic characterization based on 42 groundwater samples from public supply wells from 21 localities is presented. The isotopic composition of precipitation was measured for 7 years at two stations located in Intendente Alvear and Quemú Quemú towns, and a regional meteorological water line was built. The isotopic composition of groundwater has an average value of δ18O = -5,5 ‰, δ2H = -32 ‰, while the overall isotopic composition varied between -6,4‰ and -4,3 ‰ for δ18O and -36 ‰ and - 24 ‰ for δ2H. The dispersion in the isotopic content of groundwater, on the one hand, responds to the isotopic composition of precipitation and, on the other, to the mechanisms that modify the isotopic content of the water, such as evaporation prior to infiltration and selective infiltration processes. In addition, two mechanisms of salinization have been identified: the dissolution of salts by transit, where the isotopic composition does not change, and evaporation processes that result in an isotopic enrichment with an increase in chloride concentration.