I hate to be stupid, but how do we know salt is the good in the image?
Check your FReepmail.
The find is unsurprising, considering that all humans need at least some salt (with iodine) to remain in good health and for that matter, to survive. More is needed the hotter the climate.
Sidebar: during the colonial period the Euro militaries specified an hourly water ration for desert duty. Everyone had used that figure, including the locals after they regained sovereignty.
The Israelis studied it, found out it was one fourth the actual requirement, and that was one reason the IDF soldiers fought without running out of fight. Quite a number of the fleeing Egyptians during the 1967 retreat across Sinai, not surprisingly, died of thirst rather than enemy fire.