It's pretty bad. They've pretty much wrecked the river trophic chain by either driving away any terrestrial anima and destroying the river bank, and by shitting so much the algae bloom kills local fish.

It's gotten to a point where the local government gave the army the order to kill one of the hippos because it was getting dangerously close to a really poor village, but the troops being troops just decided to turn it into a spectacle and now they can't even kill them without people getting riled up.