I didn't know that either, however if you bury it, it will still get into the water; won't it? especially with wells? I can put it in the pail it comes in and put with trash.
Surface runoff into standing bodies of water is the biggest risk to wildlife. Or them eating the stools, disgusting as that sounds.
If buried it could get into the groundwater, which is primarily an issue if too near a well (surface runoff can also contaminate wells), that is why there are strict regulations about having livestock housed too near wells.