USE OF ISOTOPES TECHNIQUES TO REVEAL THE ORIGIN OF WATER SALINITY IN AN ARID REGION OF CENTRAL-WESTERN ARGENTINA

GOMEZ, LAURA; ALVAREZ, AMILCAR; D'AMBROSIO, D. SABINA; ZALAZAR, GUALBERTO; ARAVENA, RAMON

SCIENCE OF THE TOTAL ENVIRONMENT

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2020 vol. 763

0048-9697

Groundwateris a strategic and vital resource for agriculture and oil production in the aridregion of Carrizal subbasin CSB in Argentina. Increasing groundwater salinityin some areas has created legal conflicts between water users over the sourceof the salinity. A multidisciplinary approach using hydrogeological chemicaland isotope tolos were used to evaluate the source of groundwater salinity inCSB. The Mendoza River is the main source of recharge to the CSB aquifer.Groundwater and surface water from the recharge area near the Mendoza River tothe discharge area of the CSB were analyzed for the study. The groundwatersalinity varies between 1,000 S cm in the north recharge area to 4000 Scm inthe central region. There is a clear correlation between high level of nitrateand the high salinity spots in the aquifer. These data and the stable isotopesdata suggests the source of groundwater salinity is associated with irrigationreturn flows from the agriculture areas. This is fully supported by the carbón isotopesdata that showed clearly the input of carbon from the irrigated agricultura areasin the aquifer. No evidence was found about the role of the oil industry in thesalinization of groundwater in the study area. However, a groundwater ofdifferent origin than the recharge from the Mendoza River was founddowngradient of the oil field which needs further investigation. The results ofthis study have implications for improving water management in agricultureareas in arid environments where water resources are under significant pressuredue to more demand by an increase in population and agriculture activitiesunder a scenario of a cycle of droughts and climate change.