Here we go again. *anything* can be toxic if you have enough of it.

From the EPA: http://www.epa.gov/ttnatw01/hlthef/antimony.html
"...the average concentration of antimony in meats, vegetables, and seafood is 0.2 to 1.1 parts per billion (ppb)."

And the "staggering 700ppt" in your bottled water would be 0.7 ppb, in other words, about the same as in your food. Relax.

On the other hand, virtually all bottled water DOES contain potentially deadly amounts of DHMO. Among other nasty aspects, DHMO contains hydrogen, the chemical widely thought to be the cause of the Hindenburg disaster.