I had a flood a couple years ago and the restoration company replaced a shower stall...with a new shower pan and plastic wall surround. The pan has about a 1-2" lip around the outside edge, and the wall portion goes over top of this.
Lately there has been some black mould particles washing out from under the plastic wall portion.
I'm thinking that the wall portion wasn't sealed to the pan.
Would a good solution be to pull the wall portion away from the wall a little bit and then run a line of caulk along the pan lip...which would then prevent any water from getting onto the drywall behind the plastic wall and therefore prevent any more mould?