Being a longtime firefighter, I've had plenty of experience with "trash" that people dump in waterways. We get called out to drag for bodies when people are assumed to be lost/drowned. Sadly, this does happen and will sometimes be out there for 12+hours dragging with hooks and prodding with polls trying for a recovery.
Being a gruesome job to begin with, when you actually hook "something" you almost don't want to pull it up but alast, you have a job to do. Luckily, I haven't hooked what we were looking for, but instead have found all kinds of wonderful stuff that people throw away in major waterways.
I've pulled up window air conditioning units, bicycles, lawn chairs, a couch, a Hard Rock Cafe leather jacket, dozens of tires, chains, car bumpers, a car door, radiators, televisions, and a sewing machine!
People will throw away ANYTHING if they can get away with it. MK is lucky that people can only carry in and hide small stuff!