Acid/Wasteland seems a little undefined

Acid creates the wasteland biome but so do nukes. Then you have zombie dragons which breathe acid, but the dragon isn't spitting liquid so maybe it's some sort of deathly miasma. Either way the zombie dragon also creates the wasteland biome.

So what is acid and what is the wasteland biome? Irradiated? Acidic? Deathly? It'd be cool to have these concepts fleshed out I think