mass-effect-3
I picked up some "Turian Toxin Data" from a lab on the planet Gellix during the mission "Arrae: Ex-Cerberus Scientists." I'm assuming there's a quest out there in which someone actually wants this noxious stuff.
To whom do I bequeath my newly-acquired jar of Turian Toxin Data and where is said person located?
In laymen's terms, who wants this stuff and where are they?
A human doctor will be looking for the medi-gel formula you have in your possession following the completion of your mission on Palaven. You can find her in lobby of the Huerta Memorial Hospital on the Citadel, to your left when you walk in the door:
Outside of having completed the Palaven mission, there's nothing in particular that you need to do to trigger this mission beyond talking to her once in possession of the forumla. As Raven Dreamer notes in the comments, the doctor does have a side-conversation that would clue you into her need for the formula to begin with which you'll overheard as you approach her.
There is a group of Turians in the Purgatory bar that will accept the banner. Doing so will earn you the war asset of the Turian 7th fleet.
Best Answer
This is for an assignment on the Citadel - there's a doctor in Huerta Memorial Hospital who wants it. You should be able to complete it straight away. More details at the Mass Effect wiki.