I have a liking for Gerostiener sparkling mineral water... there are a few brands that are naturally sparkling"fizz"... all others are ingected with Co2 to give fizz like the auquafina... Perrier is from a natural source,but contains trace amounts of arsnic as does Poland Springs...

it is on the label somewhere that it has Co2,but a sure way to test is if the sparkle lasts... if you get a bottle of Co2'ed and open then close it will go flat fast as where natural sparkle last for days...