The pools of Imlad Balchorth are noxious pits of foul water. No one knows if the corruption stems from the Enemy's industry or from a more sinister source.
'Have you witnessed the foul waters that flow from Carn Dûm? In the past months, we have seen the waters from Urugarth become dark and rank with the smell of decay, but we cannot fathom the reason. Regardless of the cause, it is becoming ever more difficult to find drinkable water!
'We must learn more of these waters and the maladies that they cause as they flow into Imlad Balchorth. Here, take this phial and return to me with samples of the water. Please combine five drams of this foul water into a single phial.
'You should first draw water from the roiling patches in the pools in the eastern parts of Imlad Balchorth. The waters there cloud the minds and bind the tongues of those who come upon them.'
Imlad Balchorth's pools are to the west of Myrkworth.
The waters of the eastern Imlad Balchorth cause strange maladies, and Thorod wishes to determine the cause. He told you to take samples from the roiling patches in the pools.
Thorod is in Myrkworth, east of Imlad Balchorth.
Your phials are filled with water from the roiling pools of the Imlad Balchorth.