The toxicity of lithium is a reality. To monitor the level of toxicity you need to check the concentration level in the blood. If you start to distribute lithium in water, how can you ensure that the level of lithium remains below toxicity in the blood of each water drinker (even if you control the concentration as you don't control the quantity of water used by everyone)? Lithium is often a salt and what will be the effect of the concentration when cooking or taking a shower?
Even if lithium was added in 7up[1] before the fifties, it's not drinking water and you don't take your bath with 7up or cook your potatoes with it...
Even if lithium was added in 7up[1] before the fifties, it's not drinking water and you don't take your bath with 7up or cook your potatoes with it...
[1] http://en.wikipedia.org/wiki/Lithium_pharmacology