This quest is not available in game.
Bring the Xavian Water Sample to Deino in Orgrimmar.
The fabled city of Xavian lies nestled deep within eastern Ashenvale, and tales of its ancient knowledge are well known among the learned. It is said that the waters of Xavian hold vast magical powers.
I would have a sample of those waters, from their source.
Take this flask and go to Xavian. Gather water from the bottom of its highest waterfall, and return to me. And use care as you move through that ancient city--satyrs now hold the ruins and do not like mages prying into their affairs.