Journal of Environmental Hydrology
ISSN 1058-3912


Electronic Journal of the International Association for Environmental Hydrology

JEH Volume 14 (2006), Paper 16    Posted October 29, 2006
USE OF HYDROCHEMISTRY AND ENVIRONMENTAL ISOTOPES TO EVALUATE WATER QUALITY, LITANI RIVER, LEBANON

Zeinab Saad1,2
Véronique Kazpard1,2
Antoine G. El Samrani2,3
Kamal Slim1,2
Naïm Ouaini3

1Lebanese University, Faculty of Sciences, Hadath, Lebanon
2Lebanese Atomic Energy Commission, Beirut, Lebanon
3Holy Spirit University of Kaslik, Faculty of Sciences and Computer Engineering, Lebanon

ABSTRACT
The chemical and isotopic composition of water discharging from springs, surface and groundwater in the Litani river basin were studied. The data include field measurements of specific conductance, pH, total dissolved solids (TDS) and laboratory measurements of major element chemistry, stable 2H/1H and 18O/16O isotope ratios (d2H and d18O) of water. Water samples were collected during 2004 and 2005. Geochemical analysis indicates that sea spray influences the major ionic composition of the downstream river. Water quality changes over the course of the river in the central Bekaa plain near the Karaoun reservoir. This area drains percolated and infiltrated water that contains relatively elevated concentrations of nitrate originating from agricultural runoff. Isotopic results for d18O and d2H show that the river can be divided into three main parts relative to water quality. The upper part, near the headwaters, is directly influenced by precipitation input, while the mid course of the river is influenced by input from the Litani tributaries and the effluents from man's activities. The lower reaches of the river are exposed to high evaporation. In the Karaoun reservoir, isotope enrichment with respect to the Litani river is calculated to be more than 3‰ in d18O and 10‰ in d2H. The groundwater in Karaoun basin is recharged by direct river infiltration and infiltration from the reservoir. The percentage of reservoir recharge varies from 28.5% to 20.7% in the groundwater system.

Reference: Saad, Z., V. Kazpard, A.G. El Samrani, K. Slim, and N. Ouaini. 2006. Use of hydrochemistry and environmental isotopes to evaluate water quality, Litani River, Lebanon. Journal of Environmental Hydrology, Vol. 14, Paper 16.
CONTACT:
Zeinab Saad
Lebanese Atomic Energy Commission
CNRSL
PO Box 11-8281
Beirut, Lebanon


E-mail: zsaad@cnrs.edu.lb



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