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Rupert Pupkin's avatar

Everything in this article sounds right to me and it would be great to get rid of lead pipes, but it's not like lead pipes turn water into a nerve agent.

The linings of lead pipes are oxidized to form a coating that keeps water out of chemical contact with elemental lead. For comparison, aluminum is a strong enough reducing agent that it reacts spontaneously with water (to produce hydrogen) and oxygen (if you don't know about aluminum air batteries, look it up, it's a fascinating story). However, it forms a self-limiting layer of aluminum oxide that keeps, for example, the contents of a can of soda pop from dissolving the thin walls of an aluminum can. Also many boats are made of aluminum. This is less of an issue now, but you cannot bring mercury thermometers on airplanes because mercury dissolves aluminum oxide and, in theory, a broken thermometer could compromise the structural integrity of the plane. If you've never seen what mercury does to aluminum, go have some fun on YouTube.

What Matt was describing in DC is essentially the same thing that happened in Flint. If the pH gets off (and/or certain ions are introduced to the water) the protective layer dissolves. In the case of DC it was caused by switching chemical treatments, in Flint it was switching the water source and the story about why they didn't check for that is scandalous.

The point is, lead pipes are perfectly safe if used properly. Nowadays you can easily replace them with copper, plastic (which can also leach toxic chemicals), ceramics, etc. But that wasn't always true. There was a time when expanding indoor plumbing and bringing fresh water into houses meant using lead because plastics and ceramics didn't exist, copper was too expensive and, unlike lead, iron oxides (rust) are brittle and flake off, meaning the pipes don't last. So, surely there was a point at which Big Lead was pushing its products needlessly, like leaded gasoline or continuing to use lead paint and lead pipes when better alternatives existed, but there was a time when there were legitimate reasons to build out infrastructure with lead pipes.

Tetraehtyl lead was really horrible because it volatilized the lead and spread it around. And since lead is an element, it cannot be broken down and instead enters the food chain. Besides the horrors of particular emissions, coal-fired electricity plants are horrible because they volatilize mercury, which is also and element and also a neurotoxin. Ditto for burning waste electronics, which are full of toxic elements.

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Richard Weinberg's avatar

Your title says it precisely; well-done.

As a minor cavil, there might be no lower limit to a damaging level of lead (the issue is probably untestable), but a true zero lead level is not possible. Measuring the level of a toxicant depends on the measurement technology, which has improved vastly over the past 50 years. Supposing that one molecule of lead in a glass of water is dangerous might have a certain logical appeal but is unrealistic at multiple levels.

Lead is also bad in soil, but the problem might resemble that of asbestos in walls. The technical issue is beyond my knowledge, but the surface of undisturbed soil becomes less hazardous over time (if lead is no longer emitted), and besides the cost, it might actually be less dangerous to leave the soil alone than to try to remove it. Probably there are some sites so contaminated that it would be wise to remediate, but it's a non-trivial task to figure that out.

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