Spoil Sprawl has a nice ring to it. Personally I don't think it's going to cause too much confusion, if we're introduced to the element, then introduced to the area, most people will probably attribute the state of the toxic swamp to the nature of the toxic element. Sharing the same name would be weird if they had little to do with one another, but being a swamp there's a clear enough connection that people would see it and realize "Oh, this place is full of rot and blech and bad things I don't want to swim around in!"
Would the area itself as it might appear in-game be more navigating patches of dry land and avoiding pools of toxic swamp water, or would you be knee-deep in the swamp for the majority of the area? Just curious how the environment is going to be structured. Oh, while we're at it, might there be devices to cross the poisoned waters like giant lily pads in some of the Legend of Zelda games?
P.S. Hooray 500th post. XD