It doesn't need to have something visible it could be like in that... Magicraft..or smth when you purify crystals they pollutes environment (aura) so bat thins starts to happen to avoid it i usually build those filters which forms chimney like structures so power plants could become nice with filters on top, my idea in this post that it is quite possible without heavy changes just add pollution level var to every chunk, trees could reduce it (if not too high cause the pollution can kill even trees and hurt player) so for ex nuclear explosion could set that var really high, you wouldn't even need radiation it just be high pollution and while you are in chunk you are getting poison and stuff.. So go someone start making addon while ic team decides this idea.
ThaumCraft?