Materials safety

[russell]

Is anyone on here concerned about leeching from plastics and other materials used in an AP system?

If so, what ideas do you have for minimising that?

I am thinking about old enamel bath tubs or steel water tanks for my first AP setup.... but what about the plumbing? Are there different grades of PVC or other piping available? Or other suggestions??

I find drinking water out of a PE bottle to taste yuck as it is. But if that water is cycled round and round, day in and day out, leeching more and more with every cycle... and then the nasties are possibly bioaccumulated in the fish for months and months... hmmm... doesn't tick too many boxes for me!

[Crusty]

Hi

There is a difference between what is used in water bottles (PET) polyethylene terephthalate, which is known to leach, they are not (PE) Polyethylene and I am not aware of PE leaching anything at all. Your enamel and steel tanks will do more harm than PE in my opinion. As for pipe, some of it does contain lead so you would have to choose the right one for your application. I suggest you talk with your PVC and Poly supplier about side effects of using those products in conjunction with water and food.

[russell]

There is a difference between what is used in water bottles (PET) polyethylene terephthalate, which is known to leach, they are not (PE) Polyethylene and I am not aware of PE leaching anything at all. Your enamel and steel tanks will do more harm than PE in my opinion.

I'm curious as to what you think the issue would be with enameled steel?

As for PE vs PET, it's definitely PE that gives off the worst taste to me-- most refillable water bottles are made from it and I haven't found one yet that doesn't taint the water. I'm not disputing what you're saying about known leeching and perhaps PET leeches more stuff that just happens not to taste as bad as the stuff that PE leeches... but at least if I can't taste it I can pretend it's not there

[Crusty]

I'm curious as to what you think the issue would be with enameled steel?

As for PE vs PET, it's definitely PE that gives off the worst taste to me-- most refillable water bottles are made from it and I haven't found one yet that doesn't taint the water. I'm not disputing what you're saying about known leeching and perhaps PET leeches more stuff that just happens not to taste as bad as the stuff that PE leeches... but at least if I can't taste it I can pretend it's not there

I was more concerned with using the enameled with gravel as it will chip and wear, thereby leaching the iron into the water. Same for the steel water tanks, unless they are stainless.

As for your drink bottle, I can not say as I do not know what it is made of. If it is HDPE or LDPE there is no risk known. If it is a hard plastic noted as recyclable number 7 and is not labeled as BPA free, that may be the problem.

[jet]

Old materials like bathtubs, even plastic troughs etc have done their reacting (until they chip and rust) so may not give off much.
No PVC uses lead anymore (I dont think), it used to be a lubricant during manufacture now they use Calcium based product. DWV and Storm pipe contains Titanium Dioxide as UV blocker.
Plastics "gas" off for a while when new but should stop. High temp can cause it too. All poly and PVC breaks down in sunlight in time.
Poly products are usually mixtures of High Density PE, and Low Density PE. Soft flexible types are mostly LDPE and harder stuff has high HDPE content. Harder leads to brittleness but stronger and more expensive.
The PE itself is not UV tolerant and will break down, they add UV blockers and platicisers to protect them and keep them flexible. Often carbon black used in pipes. These are the expensive part of the mix so beware of cheap stuff.
PE is highly recyclable although products made from recycled material contain sometimes unknown mixtures and is mostly used in low value, low performance stuff.
PET is different stuff altogether, used for human food packaging etc
A lecture if anyones interested?
PVC has a few differerent types, bit confusing as things and sizes change overseas.
Normal PVC and PVC M, rated for pressure ie PN6 = 60m head, M or modified which has some flexibility and can be thinner, Measured OD. Full range of sizes.
UPVC often used in Storm or Sewer (DWV) which has no pressure rating, cheapest and is mostly what you would use for AP Id guess. Measured OD, Strange mix of sizes in each type though.
ABS - like PVC but dark grey colour, very unreactive, UV stable, often used in greenhouses and serious setups more common overseas.
Metric or Aus Std PE pipe Measured OD, external compression fittings to ~110 mm then needs welding, availiable in high pressure ratings
Rural B PE pipe measured ID, internal barb/compression fittings, only a few sizes to 50mm
LDPE pipe, 13, 19, 25, 35mm only, barb fittings and clips, rated to 40mhd mostly. Measured ID in AUS, OD rest of world so theres plenty of different sized fittings and pipe around.

Probably more confusing than helpful but there you go.
Cheers
JR

[Privatteer]

One to be aware of is electrical conduit, especially orange. Last time I checked MSDS it still has lead.

[aquamagic]

Also ,orange eletrical conduit is not ultra violet proof.The grey electrical conduit is...

[Crusty]

No PVC uses lead anymore (I dont think)

None manufactured in AU but any from china still use lead in all PVC production.