Hydrochemical and isotopic characterization of the hydrological budget of a MAB Reserve: Mar Chiquita lagoon, province

BERNAVA GUSTAVO VICENTE; GLOK GALLI MELISA; DANIEL MARTINEZ; EDUARDO EMILIO KRUSE; SEBASTIAN GRONDONA; MARIA LOURDES LIMA

ENVIRONMENTAL EARTH SCIENCES

SPRINGER VERLAG

Año: 2014

1866-6280

Abstract Mar Chiquita is a coastal lagoon located in theArgentine Buenos Aires province in South America. Theaim of this study was to perform a hydrochemical andstable isotopes characterization in order to better theunderstanding of the hydrology of the Mar Chiquitalagoon’s catchment and its water budget. Groundwatersamples were taken from 144 wells and 21 samples frommain streams, and seven lagoon water samples were alsocollected. Chemical analyses were carried out using stan-dard laboratory methods, and isotopic determinations weremade through laser spectroscopy using a DLT-100 liquid–water isotope analyzer. Hydrochemical analysis permits ageneral classification of groundwater and streamwater assodium bicarbonate waters, while the lagoon chemicalcomposition shows an evolution toward seawater compo-sition, from the north to its mouth, which is locatedsoutherly. Isotopic data show a source of aquifer rechargefrom rainfall and a groundwater domain into the streams’flow. Three main components can be recognized as endmembers in a plot of electrical conductivity (EC) versusd18O: seawater, streamwater and groundwater. ObtainedEC values for groundwater in the discharge zone (ECaverage value = 3,516 lS/cm) allow minimizing its directcontribution and to take into consideration two dominatingend members: streamwater and seawater. Mar Chiquitalagoon’s water falls close to the line between streamwaterand seawater end members according to its EC and d18O.The obtained seawater proportion for these samples rangesfrom 84 % in the la EN ESTE ARTICULO SE ME AGRADECE LA COLABORACION