Silica particles won't disolve in water, it's like breathing broken glass, and that's the main problem not limited to silica, but breathing ANY particle that harms your organs.
Lots of things don’t dissolve in water but are still effectively contained by water. That said, I wonder what happens to the water being used for this purpose. If it isn’t treated/disposed of somehow, I could see it evaporating and allowing the dust to become airborne again. If this is in a permanent shop environment, it might explain the apparent lack of effectiveness of this solution.
