TY - JOUR
T1 - Groundwater ages and reaction rates during seawater circulation in the Dead Sea aquifer
AU - Kiro, Yael
AU - Weinstein, Yishai
AU - Starinsky, Abraham
AU - Yechieli, Yoseph
N1 - Funding Information:
We thank Y. Rosenberg for his code and help with calculating the activities of radium, calculations of saturation degrees, and for fruitful discussions. We thank M. Feldman, A. Abbo and H. Hauzer for their help with lab work (radium isotopes measurements). Thanks to H. Lutzky and H. Hemo for their help with the field work. We thank O. Yoffe and D. Stiber from the Geological Survey of Israel lab for the major and trace elements analysis. We thank the reviewers and the associated editor, S. Krishnaswami, for their many constructive comments that improved this paper significantly. We thank A. Katz, B. Lazar and Y. Kolodny for their advice. We thank the Hoffman Leadership and Responsibility Fellowship of the Hebrew University, the Rieger Foundation an the Wolf foundation for the support given while working on this study. We thank the Ministry of National Infrastructure for supporting this research.
PY - 2013/12/1
Y1 - 2013/12/1
N2 - The Dead Sea system provides a unique opportunity to study flow velocities and reaction rates during seawater circulation in the aquifer. We present here a novel application of calculating groundwater age and velocity along the flow path of the hypersaline water from the Dead Sea into the aquifer using the buildup rate of 228Ra in this water. The calculated circulation velocities are 1-10m/y, which is in agreement with estimates based on the Na/Cl ratios in this water (1.5-4m/y). The latter is unique to the Dead Sea-aquifer system, where the Na/Cl ratio has been decreasing during the past 50 years due to the precipitation of halite in the lake. The velocity estimates facilitated the calculation of the rates of water-rock interactions in the Dead Sea aquifer.SO4 is removed relatively fast (k = 0.8y-1) due to gypsum precipitation while barite or celestine precipitation removes 226Ra and Ba in a time scale of years (k = 0.22y-1). Similar rates were found for redox-driven reactions, such as U removal (k = 0.4y-1) and Fe and Mn contribution due to the dissolution of oxides (k = 0.15y-1). In the fresh-saline groundwater transition zone, gypsum which precipitated from hypersaline water in higher lake stands, is now being dissolved and enrich the water with SO4.
AB - The Dead Sea system provides a unique opportunity to study flow velocities and reaction rates during seawater circulation in the aquifer. We present here a novel application of calculating groundwater age and velocity along the flow path of the hypersaline water from the Dead Sea into the aquifer using the buildup rate of 228Ra in this water. The calculated circulation velocities are 1-10m/y, which is in agreement with estimates based on the Na/Cl ratios in this water (1.5-4m/y). The latter is unique to the Dead Sea-aquifer system, where the Na/Cl ratio has been decreasing during the past 50 years due to the precipitation of halite in the lake. The velocity estimates facilitated the calculation of the rates of water-rock interactions in the Dead Sea aquifer.SO4 is removed relatively fast (k = 0.8y-1) due to gypsum precipitation while barite or celestine precipitation removes 226Ra and Ba in a time scale of years (k = 0.22y-1). Similar rates were found for redox-driven reactions, such as U removal (k = 0.4y-1) and Fe and Mn contribution due to the dissolution of oxides (k = 0.15y-1). In the fresh-saline groundwater transition zone, gypsum which precipitated from hypersaline water in higher lake stands, is now being dissolved and enrich the water with SO4.
UR - http://www.scopus.com/inward/record.url?scp=84884378038&partnerID=8YFLogxK
U2 - 10.1016/j.gca.2013.08.005
DO - 10.1016/j.gca.2013.08.005
M3 - Article
AN - SCOPUS:84884378038
SN - 0016-7037
VL - 122
SP - 17
EP - 35
JO - Geochimica et Cosmochimica Acta
JF - Geochimica et Cosmochimica Acta
ER -