It has often concerned me how ubiquitous PTFE ("teflon") is in plumbing. It's used to seal leaks between non-soldered pipe, such as brass or plastic compression fittings. PTFE tape even comes with some plumbing fittings.
For those that don't know, PTFE falls into a
class of compounds that have been nicknamed "forever chemicals". These chemicals are very resistant to breaking down in the environment and, as a result, tend to accumulate inside living organisms (an effect known as "bioaccumulation"). The extent of the damage that these compounds may cause is unknown (yet they are generally accepted to be carcinogenic and toxic - see the class action suit against DuPont) but there are regulations being put in place to limit human and animal exposure to them.
Talking to a plumber friend of mine, she mentioned that plumbers used to use hemp or
flax fiber with a sealing paste instead of modern tape or compounds. The effect is the same in that the filler material swells to fill any gaps and repels the
water, creating a seal.
You can still buy hemp and flax plumbing fiber and it seems to be a similar price to the alternatives.
Unfortunately, I looked at the sealing pastes that are sold with the natural fibers and these seem to be very nasty.
To take one brand at random, I looked up the safety sheet and found that it contained 9.9%
octamethylcyclotetrasiloxane. This chemical, which I had never before heard of, is listed as a "persistent, bioaccumulative and toxic substance" and is highly resistant to being broken down. Wiki describes it as having "low acute toxicity" but also that it readily bioaccumulates so chronic toxicity
should be an important consideration too.
All of this is to say, does anyone have any
experience or suggestion for functional, non-toxic sealing pastes that can be used for drinking-water or irrigation pipes alongside a hemp filler? I would love to move away from the toxic-ick that seems to be the normal choice.
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