The slain elemental has produced an intensely glowing globe of water. The contents of the globe are, at best, disgusting. It would be safe to assume that whatever has befouled the water of Mystral Lake is most likely present in the water of the globe.
It's not exactly common knowledge who might be interested in such a find; perhaps Mastok Wrilehiss at Splintertree Post, might have an idea.
Yeah, what do you need?
You find a nasty ball of water and decide to bring it to me? Who am I, the Earthen Ring or something?
Actually, that does give me an idea... perhaps you do need the Earthen Ring for this. I mean, if it helps clear up the situation at the lake for good, then I'm all for it.
You know who the Earthen Ring are, <name>?
Upon completion of this quest you will gain: