As I saw today the Buffaloos bathing in the Pond and the Wildebees did drink out of it, I came to following factors:

The Pond is about 1,2 Meter deep (ca. 4 feet) at the deepest. Its, 8 x 13 Meters. This makes roughly, (cos Pond is round, different depth)
8000 liters of Water.(Which is not much)

As I said, the Buffaloes were in there, Hyenas, Elephants are the bathing fraction. Egypt and Tian are doing their part to it. Turtles, Frogs, Reptiles as well.

All is standing in an Ambient Temp. of 30 Celcius, by means the Water temp might be about 25 Celcius.

The Coli Bacteria must be boiling in there. I assume, that the self cleaning abbilities of the Pond, to stabilize the Water Quality, are next to nothing.
(Putting the 8000 Liter and Frequence of Visitors in Consideration.)

If an average Human would drink a Handfull unfiltered, unboiled water out of there now, I guess the Diarriha would dehydrate him, or he dies instandly of a Coli Intoxication.

My Question, when is the point of pollution reached, that even the Animals will not drink this water anymore ?

I mean Ponds , artificial or not, are over years in the Parks. What is the experience with this ?