Is the Pipe Poisonous?
Many ask the question about PVC pipe, should I use it in my home or commercial project.
Most folk use PVC mostly because at this time there is not much else readily available. Some folk really worry about PVC. There is a load of info out there on this kind of subject but, we need to remember, "the road to better, purer food is a journey, not a destination" In other words, we need to use the best materials that are available to us today. Don't stop the journey because of a small difficulty. It is far, far better to go ahead and produce clean carefully grown food. Keep moving forward on the journey.
The plasticizers in PVC that some worry about, and in other types of plastics need to be fairly warm before they start to gas off. Additionally, the inside of the pipe work will be very quickly coated with a layer of biofilm thereby effectively sealing off the PVC from direct contact with the system water. I realise this is an emotive issue with some folk but we need to achieve a balance and use the very best materials we can secure for our project. Some folk who will just not use PVC because of the perceived problems still commute to work in their plastic car, ride in plastic lined aircraft, work in a plastic office, sit on chairs filled with very dangerous plastics and so on. In short, we are surrounded by plastic of one kind or another. The exposure of the Aquaponics system water to any danger, real or otherwise is so small by comparison to other plastic products.
Aquaponically grown produce is way, way better than anything on the supermarket shelf, even if we do have some materials to deal with that may be slightly less than our ideal.
The ideal material at this time is HDPE. There is plenty of HDPE pipe, but the fittings are extraordinarily expensive. HDPE pipe can be obtained at most irrigation supply stores. You will not usually find it in plumbing stores or hardware stores. HDPE stands for High-Density Poly Ethylene. Poly Ethylene is said to be the only real food safe plastic material along with common old fibreglass made from properly cured polyester resin.
So, the important thing to do is get started, be prepared to use better materials when they become available, but....get on the road to better, more sustainable, nutritionally dense food for you and your loved ones.
Posted By Murray Hallam on Friday 31st July 2015 @ 02:33:49
Updated : Friday 1st September 2017 @ 13:43:23 | Words : 429 | Views : 52 | Comments : 21
Posted By Murray on Thursday 23rd August 2018 @ 04:06:57
Bisphenol A (BPA) is the main chemical when concerned with plastics contaminating food products. BPAs are used as an antioxidant when constructing soft grade PVC, but they are not used to manufacture rigid PVC (which is typically used for pipes)
Posted By Steve Goyne on Monday 28th May 2018 @ 10:06:55
Hi Mat, Thanks for your very informative comment. I shall explore the website you have give the link to.
Posted By Murray on Thursday 1st October 2015 @ 13:40:15
First of all thank you Murray for your inspirational and enthusiastic contribution to the modern aquaponics movement. You as well as others have inspired me to take the step from traditional gardening of shoveling manure and sea grass around to a more automated aquaponics food production system.
I am in the design / component purchasing stages of my Aquaponics build and I too have had concerns about leaching plastic materials, however as Murray suggests I plan to use what is available, practical and affordable until alternative solutions are available.
As background information I am a designer / engineer based in NZ. Most of my working career has been in technical apparel and equipment design for the outdoor industry which observes many step change developments with regards to plastics, chemical management and so forth. Although this is not the same technical field as aquaponics and pipe plastics, there are similarities in the base materials mentioned.
The suggestion that HDPE / PE / LDPE is the best plastic to use for a system is correct as PE is considered a stable inert plastic. Unfortunately HDPE is often only supplied in roll form here in NZ making it hard to build a system due to the pipes precurve, HDPE fittings are hugely expensive and straight extruded HDPE is vary rare in NZ and really only available in large commercial diameter sizes. Stainless steel is just not viable due to costs and complexity. Therefore I plan to use HDPE / PE where I can (tanks & growbeds) and UPVC for all pipework and fittings.
The U in UPVC stands for Un-plastersied. Plasticisers are additive agents in PVC that allow PVC to become soft and flexible. 90% of the worlds plastercisers are used in PVC production and they have a tendency to leach by evaporating as a gas. When you walk into a cheap shoe store or pull a new kids PVC paddling pool out of its packet you often smell that really strong plastic smell which is the gas build up of plastercisers. An example of a PVC that has leached its plastercisers is a garden hose that has gone stiff and brittle, my experience is that cheaper garden hoses leach faster than quality garden hoses.
As mentioned, UPVC or sometimes called PVCU is a PVC with no plasterciser in it, the material is stiff, but should be much safer than just PVC. We get UPVC here in NZ in the form of pipe and fittings. I plan to get my pipe form NZ but my UPVC fittings from:
If you contact this company direct and buy all your fittings direct in one go then they give you bulk rate prices. As an example they have quoted US$ 0.23 for a high pressure 25mm 90 degree elbow. My initial Aquaponics plan had 288 fittings and they quoted US$ 143.10 for all the parts and US$ 146.00 for shipping (Total US$ 289.10) which is pretty good considering a high pressure 20mm 90 degree elbow is approx NZ$ 4.00 at my local plumbing supplier.
All in all, the Aquaponic PVC situation in not ideal... but as some have indicated it is highly conceivable that smelling petrol fumes at the local gas station while filling your cars fuel tank or gently breathing in the off gassed plastercisers from my laptops power cord while I write this reply is probably much worse for ones health. It is down to the individual how they interpret information and manage plastics / chemicals in their life.
I hope this information helps, I look forward to your reply.
Kind regards, Mat
Posted By mat mat on Thursday 1st October 2015 @ 10:53:30
Cannot give an opinion on that as we do not have it here in Australia that I have seen to date. Sounds like it might be a move in the right direction. I will investigate more from my end and if it is better I will move to it immediately.
Thanks for the heads-up.
Posted By Murray on Wednesday 5th August 2015 @ 00:20:01
What about PVC-U? Is this better than standard PVC? I though was for potable water and is better than standard PVC. Can someone confirm this?
Thanks in advance. Love your articles.
Posted By Emilio on Tuesday 4th August 2015 @ 23:53:43
HDPE is available all over Florida in irrigation supply houses, there are usually at least 2 in each city. [Kissimmee has 3 that I know of with out running a goggle search.
Posted By Neil Orris on Sunday 2nd August 2015 @ 20:07:02
Good article Pete, but careful reading will show that the exposure to the not-so-good aspects of PVC is miniscule in an Aquaponics system, very possibly unmeasurable. Let's move forward asap and use better materials.
Your question about PEX pipe, yes, it is available in Australia. Last time I looked it was very expensive. Thanks for bringing the up, I must investigate again and see how things are there.
Your question about PVC in Australia. Lead has been removed from PVC pipe here and there is a deadline for the removal of lead from the joiners etc.
Posted By Murray on Sunday 2nd August 2015 @ 19:51:31
Murry, I appreciate this discussion, since I am very interested in hydroponics and think your system is the best solution created. Since I realize the system you have developed is based upon resources in Australia (though easily adaptable to local resources) I am curious as to several points. Further reading I noticed comments regarding PVC developed to "Australian" standards. From my observations, Australia seems to be more concerned about the general well being of people than corporate influence govt regulations in USA. Does the PVC in Australia have different standards?
In addition, how available is PEX pipe in Australia? 5 years ago in Florida, it was only available to plumbers. Now it is on every shelf for the "big box" home improvement shelves.
Posted By Pete on Sunday 2nd August 2015 @ 13:39:07
Hey Rich, my concern is whether the tilapia fish species would be a good measure of the carcinogenic/health hazards to humans. "Canary in the coal mine" is a good idea, but I would also point out the resistance sharks have to cancer. I would suggest not reading this link
Posted By Pete on Sunday 2nd August 2015 @ 13:26:46
Hey Rich, I have been looking for the information you are curious about, but have never seen research done. Other solutions would be some sort of filter system, though this may create more daily/weekly maintenance.
Posted By Pete on Sunday 2nd August 2015 @ 13:22:24
Neil, I think this is a great idea with safe alternatives to PVC.
Posted By Pete on Sunday 2nd August 2015 @ 13:03:38
Thanks for tackling this problem. I have been interested in it since I started with Aquaponics after seeing your first videos. After three year of growing talapia I have observed no ill effects in my fish and I think that if the pvc was really bad I would have seen something in the fish. My fish breed very well, well like fish. I don't even have to try to breed them in my one thousand gallon tanks, I just harvest and there are always plenty of young to fill in for the big ones we eat. I have seen NO abnormaities, and there is an abundance of fish in my tanks. I do hope you keep this format going because it is really important.
Posted By Rich on Sunday 2nd August 2015 @ 03:20:15
Hi all, I agree with Murray. Jumping into a car on a hot day once, will most likely expose you to more toxins than you would ever have leach into your system.
Posted By greg on Saturday 1st August 2015 @ 00:31:17
No, I have not seen any such reports or indications. The thing is, we need to minimise our exposure to dangerous plastics. PVC pipe in our AP system is possibly the least of our concerns. But....when better materials come along we should move to them ASAP.
Posted By Murray on Friday 31st July 2015 @ 17:19:07
All good points. Evidently there is a new product recently released in Germany. I am trying to get info on it. As time goes by, we can just hope materials available will get better, and as soon as they do I for one will leave PVC far behind.
Posted By Murray on Friday 31st July 2015 @ 17:16:05
Fiberglass [PROPERLY APPLIED AND CURED] over bamboo might be an excellent answer, and provide for joints ... after drilling out the internal cell barriers at each growth ring of the bamboo, miter the bamboo as needed then wrap the joint with glass tada a bamboo lined fiberglass pipe
Posted By Neil Orris on Friday 31st July 2015 @ 16:57:11
I agree with your conclusion but I was also wondering if the plant itself can filter out or avoid drawing PVC by products. Do you of any reports on the amount of negative chemicals in the water and plants? I guess what I am thinking is that there are probably only low PPM in the water and even lower in what the plant actually draws into itself.
Posted By Rich on Friday 31st July 2015 @ 15:45:25
I can appreciate the point made by this article regarding PVC, but I would disagree. Yes, we are surrounded by plastics on a daily basis. However, there are proven carcinogens in PVC which are released over time in water. I have confirmed this though Internet research (search for MSDS PVC). I have also spoke with 2 certified plumbers and a home inspector, all three cautioning me on the hazards of using PVC for potable water.
I would suggest some other alternatives than HDPE. The first is "CPVC". This solution is older, but effective. CPVC is approved for potable water. Down side of this, is that it does not handle UV light and will degrade and become brittle (in Florida, give it about a year). A second alternative is the newer "PEX" pipe. Very easy to work with, approved for potable water and weather resistant. Downside is that it is more expensive than PVC and there has been some research that has indicted that if buried, a few insects will bore through the pipe over time (though the current industry seems resistance to these research conclusions).
Posted By Pete on Friday 31st July 2015 @ 13:45:09
Just last week when I was in Oregon I saw bamboo pipe pieces being used and it would appear that it lasts a couple of years. Splitting appeared to be the main problem. Go for it I reckon. Give it a try.
Posted By Murray on Friday 31st July 2015 @ 06:51:48
Silly as this may sound, what about Bamboo? Will it get "soggy" after a while? I'll be moving back to Indonesia in about a year and want to go a bit Gilligan's Island and there's plenty of natural stuff there. PVC for when I get serious.
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