Which pipe to use for irrigation, concerns using plastics, please help

Im stuck in the beginning phase of a 7 acre food forest design. Im located in north texas and the design im look at will be a keyline design. the external water supply will come from a meter on the highest point on the property, i want to design the swales to flow water from rain and or from flooding from the water meter, but i also want to run a pipe from the top of the property at the meter to a pond 1000ft away on the lowest point of the property, the pipe will serve two purposes, i will have supply water from the meter to the greenhouse next to the pond, and i will use the pipe to pump water from the pond up to the top of the property to flood the swales when the pond is full. My main concern is i do not want to use pvc, and possibly any plastic in the system at all if possible, i want to prevent any leaching of harmful chemicals into the water im using to irrigate with. What are my options for materials for plumbing that are the least toxic, and wont break the bank entirely. any advice is appreciated.

Here's an article about the toxicity of different plastics: http://io9.gizmodo.com/how-to-recognize-the-plastics-that-are-hazardous-to-you-461587850

thank you for the article, i have read a few articles that were quite similar to this one, but they still leave me wondering if there is any plumbing that will not leach harmful chemicals into the irrigation water. of course there is the option of copper but at 1000ft its just not in my budget, im wondering if iron or steel pipe of any kind would be better, i would rather have extra iron in my water than hormone disruptors, i want to build this system with a higher standard than what is common right now, we know plastic is causing many problems to our health and the world, so eliminating it from the irrigation water is my overall goal, i know we cant escape toxins entirely, but i is my goal to eliminate bringing them into my system.

One option might be to grow bamboo to link around pvc pipe. Bamboo isn't good for pressurized systems as pipe, but it works great to protect pvc from solar radiation and prevent it from breaking down and leaching chemicals.

If absolute control is the goal then copper pipe will be your best bet.(even copper has problems)  The problem with even steel pipe is trace heavy metals.  And because it is corroding faster it will expose more even though it likely has lower concentrations than the plastic to begin with.


Another answer would to accept a certain amount of problem and then work to moderate it.  For reasons of reliability I would choose black poly pipe.  The high cross linked one used for drinking water would probably be a better choice over time because the chemical bonds will have stuff tied up.  Flush it with an acid and a base before you start using(ie lye and vinegar) to get any trace heavy metals moving.  As for endocrine disrupters there are a number of articles on sewage treatment that look at them.  One of the common answers is a biological destruction mechanism like a marsh.  For small scale use would a sand biofilter get where it did the same thing over time?  Also remember dilution principles.  A pipe system flowing 5 gallons per minute steady for a year will have been flushed by 2.6 million gallons over the course of a year.  That means that if you have a full gallon of endocrine disrupter in your piping system that it would have been diluted in 2.6 million gallons of water.  Since it is likely way less you would likely be talking dilution of 10 million to 1.  And as the pipe gets leached out each progressive year will be less.  Bury the pipe to keep the temperature stable to reduce leaching as thermal cycling increases leaching because of mechanical stresses.