Meadowlark's comments about the muck danger are right on.

Don't wear any shoes that you are not prepared to loose.

When I've had to tread into muck for whatever reasons, sometimes I place a wood pallet down to distribute my weight.

Excerpt from Robert Crais' "The Monkey's Raincoat:"
"She took another microscopic bite of her sandwich, then pushed it away. Maybe she absorbed nutrients from her surroundings."