From what I've seen in the Hydroponic world, plastic and pvc is necessarily used frequently and people get great results. Even Epcot at Disney has a huge exhibit of hydroponics and they use loads of the stuff. I think NASA does too, last I looked.
I think the plants themselves tend to be more sensitive to the chemicals. Like for instance, you can't use tap water with the plants because of the chlorine will kill them. You have to use well water or dissipate the chlorine from the tap water before you use it with a bubblier over a few days.
Seems to me that the plants would be the first to complain, but I don't know for sure.
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