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PVC vs Hydroponics and Rain water collection - a timely warning Answered

Hello one and all-
I've been interested in hydroponics for a very long time.  Now the time has come around that I should get out and get some form of it built and begin using it.  I began researching different styles and of course reading here on Instructables.
I read about all the different styles and methods.  I looked at kits, partial kits, and building my own design. 
I also began to think about moving away from the use of the well on my property.  I looked into rain water capture.  Here in the north east there's been no shortage of rain even in a "dry" year.
In nearly every tutorial or kit I've found them based on a PVC product or using PVC materials.  I remembered that there had been an issue with Lead (Pb) being in PVC.
I looked it up.  It appears that there are serious issues with the use of PVC and Lead is only one of them.
Here is a sampling of the links to the issue of Lead in PVC -
This is just a few links - there are a ton more.
It's an interesting read and should give everyone working with PVC cause for pause.   For example instead of using the PVC gutters I had planned on for the rainwater collection I've been thinking about making them from wood (Plywood) and coating the inside with Food Grade Shellac.  I will be using PVC pots for container vegetable gardening this year but I will rough up the interior of the container (taking precautions - respirator, gloves etc) and again using Food Grade Shellac to prevent the PVC coming into contact with the growth media or growing vegetables.

I was sort of surprised by this info and just thought I should share it just in case someone was unaware of the issue.  I would like to cross post this but am not likely to do so for concern of running afoul of some rule.  Feel free to share this info though.  In fact please share this widely-
Good luck with your projects,



6 years ago

If your reason to use rainwater is to handle water shortage maybe you should also look at aquaponic systems. It is a combination of aquaculture (fish farming) and hydroponics (growing plants in water) which eliminates the need for major filtering and water substitution. This type of system minimises wasted water and seems to be very popular in dryer regions (there are several videos of an aussie guy who builds these systems which really clarify how it works).


6 years ago

PVC pipe is pretty much inert at the moderate temperatures you would be exposing it to in this project. The problems come when it is heated excessively or burned. That is when the toxins can be released, like with most plastics.


6 years ago

Er, your first link provides data to show that lead in PVC pipe is no problem at all, except for traces being washed off the surface of brand new pipe in the first five days - nothing migrates from the pipe to the water in the pipe, nothing migrates into soil or landfill, and even when they assume the pipe fully decomposes (over a period of 100,000 years), the amount of lead released is a negligible increase on the natural levels of lead already in the soil.


6 years ago

Would one be more worried about acid rain you collect or the amount of leached chemicals that might be present? You are not directly drinking the collected water but what amount is absorbed by the vegetables? In that case, none of the world's food supply would be safe.