I use PVC, and I'm assuming that most of you do as well, but there are rumblings out there about it leaching carcinogenic nasties into the water. My understanding is that this happens mainly when the pipe is heated, but that is exactly what we have in the summer.
Is anyone using an alternative in a bigger system? We've used some flexible vinyl tubing...but I sure prefer PVC. Thoughts?
Thanks again, everyone. Lots of great points being made!
I happened to come across insulation for pipes at a recycling center, I will try to find out the specifics but I would assume a plumbing or building supply would be able to get them (if they didn't already stock them). Insulated pipes would also keep pipes warm in winter.
Cheers, Nick Grow It Right Aquaponics
The best article anyone can read as of now.
good article claiming for both sides...
let's all take it upon ourselves to start condcuting tests to see if dioxin and bisphenol a are leaching into our fish and veggies. i will let you know what i find and hope that you do the same. the best way to go about this would be to start connecting with your local university that has labs that can test for this kin dof stuff... i'm sure students would love the opportunity! maybe they can even make this their thesis!
While I hate that the manufacture and disposal of PVC piping can be bad for the environment, the alternatives are not all that easy to come by.
The dioxin is released if the PVC is burned and since we are not burning the PVC to power our AP systems, I'm not too worried about that coming from Ridgid pvc pipe or plastic used in the AP systems.
However, I will say, I don't want to use Flexible PVC in my AP systems. Flexible vinyl liners or other flexible PVC are the ones more likely to leach less desirable things into our food and are therefore the type of PVC I will work to avoid. The chemicals used to make them flexible and to help them remain flexible even under UV radiation are the ones that worry me.
I am not worried about what the PVC or other petro-based parts of the systems can leach. But I think some thought should be put towards coming up with natural sources for the parts we use in are systems. not only for eco friendly production but to also insure that future generations will have the resources to build systems.
I am new to aquaponics, having just attended the Green Acre's course, and I am getting a mailshot from another source now which is again questioning the safety of PVC in aquaponic systems. As far as I can tell there isn't any new evidence about PVC, but some are switching to HDPE to be on the "safe" side. Does anyone know of any NEW evidence against PVC in AP systems? I ask because we are about to set up a backyard system, and to be honest whilst don't feel overly concerned and will probably use PVC in the first instance, I am concerned that this sort of adverse publicity could damage commercial aquaponics in the future if we don't get it right now.
I do agree with Jason that we should be looking towards more eco-friendly materials, as even if PVC is confirmed safe in AP systems it is a bitch to recycle or destroy, causing all sorts of unpleasant waste products. Probably if I was looking to set up commercial now I would be looking hard at HDPE but I have no experience in the plumbing aspect and how difficult it would be.
Any ideas or new info?
Just realize that almost all commercial hydroponics is heavily using PVC.
Almost all the "bad" things about PVC have to do with either the Flexible kinds (the nasty hormone mimicking plasticizers) or with the rigid pvc it is the manufacturing and disposal that are bad, not the use of it. So don't be burning PVC to heat your greenhouse since that would release dioxin unless burned at just the perfect temperature.
Now HDPE pipe is more eco friendly, however it is more $$ and more difficult to join since glues or cements don't work on HDPE and you have to either heat fuze the connections or you have to use compression fittings.
I have been using recycled HDPE here for some time. I like it because of its flexibility. It will make long radius bends with ease. I have been using standard PVC fittings when needed and gluing them to the HDPE with polyurethane sealant. The polyurethane is an excellent adhesive as well as sealant which remains flexible when cured. Since it remains flexible it will handle the expansion and contraction of the HDPE without breaking the seal. I sand the sealing surfaces it ensure good bonding. This will only work in no pressure or very low pressure situations which is the case in most aquaponic systems.
The crux of what I learned while looking into it recently: If you're going to use PVC, what you'd want to use is UPVC, Unplastified PVC. In my area that's not what you find in the hardware store meant for drains, as that's often plastified, i.e. containing bad stuff that will leak, and not food safe. PVC meant for plumbing water supply is normally UPVC and would be good to use.
Aside from that, yes, there are apparently other reasons PVC isn't the greatest thing in the world. Here's an informative overview of better or worse plastics: http://archive.greenpeace.org/toxics/pvcdatabase/bad.html Yeah, HDPE would pretty much be the best thing to use all around.
If PVC is heated due to extreme temps in order to leach poisons into the wate, then it will be a constant boil and you need not cook your fish, Nature will do it for you. Since the water is constantly flowing and in an even temp, I doubt it will be a danger to use PVC. Just my thoughts
keep in mind... no matter what your AP system is plumbed with, your water still came from a PVC or Copper pipe inside your house.