There is plenty of info on-line here are some;
six sources of bottled natural spring water were purchased and analyzed for silver, arsenic, barium, beryllium, cadmium, cobalt, chromium, copper, mercury, molybdenum, nickel, lead, antimony, selenium, thallium, vanadium, and zinc. All of these metals except beryllium, mercury, and thallium were detected in at least one of the bottled natural spring water sources.
My choices would be 1) Distilled 2) RO 3) Rain (I am in a remote area) 4) Bottled... YMMV