ucg and fish, page-4

0.1 to 0.2% is 1 to 2 litres of untreated UCG water per thousand litres of normal water.

That's a pretty high concentration. To achieve that a UCG company would have to be pumping untreated UCG condensate directly into watercourses, and I'd be in the lynch mob myself if they did that! (figuratively speaking of course)

But it does show the problems that could occur by losing control of the pressure gradient in the gasifier and letting this stuff loose into the aquifer, particularly in areas that use these aquifers for town drinking water.

Also the fact that ammonia was a major by-product suggests to me that this UCG was conducted with air injection rather than oxygen injection, because nitrogen is a very minor component of a coal seam. Oxygen injection would go a long way to eliminating nitrogen by-products like ammonia and the NH4 molecule would presumably stay as two H2 molecules (ie pay dirt!).

Not much you can do about the benzenes, phenols and other aromatics, though.