Comment by PeterHolzwarth | Hacker News Reader

Comment by PeterHolzwarth | Hacker News Reader

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I have no idea if this is true (and honestly can only barely remember the reference, which I read maybe a decade or two ago), but I believe I saw a comment that the interior of lead pipes eventually develop a "calcified" (don't know what else to call it) lining of the lead reacting to water, such that lead stops leeching into the water that passes through the pipes.

I believe this came up when reading something about how the trend of traditional historicity has always been to identify the Big Major Cause of the fall of the Roman empire, but that each explanation ultimately falls short. The followup point made by this, of course, is two-fold: that "falls" are often very complex and multi-faceted; and that the Roman empire never really "fell" in the Gibbons sense - it just slowly evolved, and eventually shifted east, finally becoming self-consciously retro-classically Hellenized, and just morphed to something new and lasted another thousand years -- but never actually fell during that time.

Anyone else have any thoughts or insight on the "lead pipes eventually line themselves with something non-lead-like" angle?

I haven't read it, but the book History of Toxicology and Environmental Health [0] would say that pipes were not a problem. Preparing food and wine in lead containers could have been a problem, but it wasn't until centuries after the Roman Empire "fell" that doctors even described the symptoms of lead poisoning.

And to throw in another quote from a scholarly source, "Water from the river Anio, which fed two of Rome's principal aqueducts, the Aqua Anio Vetus and Aqua Anio Novus, was particularly hard and conveyed high levels of dissolved calcium carbonate. Indeed, Frontinus complains in his treatise on the aqueducts of Rome, that "the accumulation of deposit, which sometimes hardens into a crust, contracts the channel of the water" (CXXII.1)." [1]

[0] https://www.sciencedirect.com/book/9780128153390/toxicology-...

[1] https://penelope.uchicago.edu/encyclopaedia_romana/wine/lead...

I hope I can be forgiven for replying to myself, but at this timestamp, I've got three excellent replies affirming the "lead pipes get gunked up and it stops being a notable problem" concept.

Thanks for the replies! Great stuff from all of you.

> would say that pipes were not a problem.

You obviously would prefer non-lead pipes, but running the water for a period before using flushes out any lead if the pipes are in the house. Like you say in your comment, it's when water sits in a container like a wine vat where leeching has time to accumulate.

That's a great reply, thanks, and seems to align with the "pipes just get clogged up" concept I read some time ago.

It's called mineralization, and happens so long as there are dissolved minerals in the water and PH is correct. Lead contamination happened in Flint, MI because additives to control the water PH were neglected to save cost, and slightly acidic water ate away at the mineralization layer in the pipes and began dissolving the lead again.

I don't know if I would call Flint's water just "slightly" acidic. It was acidic enough for the Flint hospital to complain about their stainless steel sinks rusting, for local automotive plants to dig their own wells because it was destroying parts they were washing, and turned their entire water supply system into swiss cheese that had to be replaced. It might be slightly acidic compared to highly concentrated acids, but in terms of potable water it seems extremely corrosive.

Of course you are right, and no offense meant. I grew up in Flint, and have family there to this day. My intention was more to communicate that even small changes in water PH can affect this mineralization layer.

What I rarely see talked about with regard to Flint's water supply is that Detroit was willing to give them water for free, which is documented, and the only explanation that makes sense as to why they weren't taken up on the offer is the state governor's cabinet connections to fracking and a pipeline intended to bring lakewater inland to facilitate fracking. They wanted the taxpayers of Flint to help foot the bill. See: http://banmichiganfracking.org/the-flint-water-connection-to...

Yes, the piping in my parents’ house is all lead, but not worth replacing due to the above. It’s pretty common in old houses in Britain

Very interesting. I recently found out the house I grew up in in the UK over 15+ years had lead pipes that were never replaced, and I always wondered why they were not replaced and if it had some cognitive impact. This lining effect likely explains the reason, and offers at least some reassurance.

If the water PH changes, the value in replacing those pipes might become more apparent.

But my sweet water!

I wonder how did you figure out this is the case, did you make any tests of the water?

I can hardly imagine living in a house with lead pipes. I mean even if water if provably safe today, what if tomorrow PH shifts to acidity.

I have some late-19th-century books on plumbing that mention the same passivation layer, and so clearly it was known, along with some of the toxic effects of lead, back when it was widely used for plumbing (which I must also mention that the 'plumb' comes from 'plumbum' - Latin for lead.)

Also when talking about downfall. I think it is also sensible question timeframe when these materials were first used. Was that during raise of empire or after it? As it feels wrong that something that had been used for generations during formation of empire would lead to downfall...

There must be something, as I grew in a house with lead pipes, and while I will not disclose my IQ or that of my siblings, they are high. Or maybe we were lucky? Of course only anecdotical data.

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