I’ve looked up the possibility, but I’ve been told that mold or decomposition can happen. I don’t think this happens all the time, I would just rather not take the risk

I’m planning on lining the styrofoam with some sort of clear plastic film, I’m not sure of the brand or type - I just found it in my basement. There will be a hole with a stopper at the bottom - still trying to figure out how to seal the plastic to the pvc pipe that will run through the hole.