Cl/Br ratios of Lake Kinneret, pore water and associated springs

The Cl/Br ratio (wt/wt) of port: water in a lake, having diverse saline inp uts, was used to distinguish among the influx of different water sources an d estimate their relative; contributions. Pore water concentration profiles obtained by a passive multi-layer sampler from bottom sediments of Lake Kinneret, Israel, depict Cl/Br ratios that v ary between 70 and 156 and are similar to ratios in nearby onshore springs - Hamei Tiberias and Fulya, respectively. The Cl/Br ratio of the lake (135) is strongly influenced by the Cl/Br fingerprint of Fulya-type water. Howev er, the discharge of the known Fulya springs can not provide the required B r- mass (about 648 tons/y) to maintain the Cl/Br ratio in the lake. Therefo re, diffusive and advective fluxes of port: water are additional important mechanisms by which Br- is added to lake water. Moreover, it is demonstrate d that a combination of Fulya and Hamei Tiberias-type waters (90 and 10%, r espectively) can explain the Cl/Br ratio of the lake. The areal distributio n of the Cl/Br ratio in pore water may be the result of dilution of an anci ent evaporated solution (Cl/Br approximate to 70) with fresh water from adj acent aquifers (Cl/Br greater than or equal to 150), followed by mixing wit h a saline solution having a high Cl/Br ratio (Cl/Br approximate to 300) Th e results of this work suggest that the Cl/Br ratio is a sensitive tool for the study of other similar environments. (C) 1999 Elsevier Science B.V. Al l rights reserved.