Salt Leaching in the Newly Exposed Shores of the Dead Sea, Israel

Abstract

Surface samples were collected from three sections across the newly exposed shores of the Dead Sea. Analysis of the water content of the sediments as well as the Cl and SO 4 concentrations of the sediment solutions was conducted in order to check the effect of leaching by rain on the sediments. In all cross sections decrease in salinity and chlorinity with time of exposure was observed and was taken to represent the leaching effect of rain. High salinities near the shore reflect input of sea spray. Only the dssl0 cross section represents conditions unperturbed by the upwelling of groundwater and thus enables one to assess the effects of rain leaching only. The spray zone in the dss10 case dominates the sediment solutions up to 12 m from the shore line (equivalent to an exposure period of 3 years). From then on salinity decreases until constant salinities are reached at a distance of 27 m from the shore line corresponding to about 9 years of exposure, at a [Cl ^--] concentration of 0.3 eq/l. In the other cross sections (dss3, dss9) the effect of groundwater input (of saline/fresh type) was more significant than the effect of rain in adding/ removing salts from the sediments and therefore the pattern of decrease in salinity with time was perturbed. Relatively constant gypsum concentrations in the sediments in all cross sections indicate that the amount of rain that passed through the sediments in the last 50-60 years was not sufficient to cause a significant dissolution of gypsum.