Actually it does leaches; i mean it might not affect the chemistry in a method that is easy to measure but it does leach chemicals that can cause cancer (at least in people):PVC does not affect water chemistry.
I used this:What kind of glue did you use on the fern? Here in the US we use Super Glue Gel.
I had 1 tank "melt down" last year & most of my plants, including most java fern & some anubias leaves died. I was shocked! I don't know what happened but all the plants are slowly recovering. It may have been a tap water problem or ??? I've never had java ferns or most anubias do that & I've kept them for 40 years.
My ferns & anubias were just wedged in between rocks not glued or tied with thread...