It's not. PVC is used for water lines, drinking water and 1000 other things. Fuck, are you a troll or just really fucking retarded? Do you know how many hydro systems are made by drilling holes into PVC pipe? Long term, PVC probably isn't the greatest shit for the environment, but short-term, it's great, because it's near-indestructible, relatively cheap, inorganic (no mold), holds up to water, can be cut with a saw, lightweight, bought anywhere... Show me one plant that died because of PVC and I'll show you one grower who doesn't know what killed his plant.