SELF-DIFFUSION OF WATER IN A NATURAL HYPERSALINE SOLUTION (DEAD-SEA BRINE)

The self-diffusion of H-2 O-18 has been studied empirically in Dead Se a brine (TDS approximate to 340 g/l), a natural, very saline solution composed of mainly Mg and Na chlorides. Experiments were conducted in dialysis cells with O-18-depleted water at an ambient temperature of 2 2 +/- 1 degrees C. The selfdiffusion coefficient in DS water is 1.8 x 10(-5) cm(2)/sec, about 25% lower than the known self-diffusion coeffi cient in distilled water. Knowledge of the self-diffusion coefficient in hypersaline solutions is of importance for the determination of mas s transfer in brines, at sediment-water interfaces in lakes and in int erstitial solutions of saturated and unsaturated porous media in aquif ers.